GuidelinesforCarbonAccountingandEmissionReductionIntheUrbanWaterSectorOrganizedbytheChinaUrbanWaterAssociationEditedandtranslatedbyXiaodiHaoandRanbinLiuDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorOrganizedbytheChinaUrbanWaterAssociationEditedbyXiaodiHaoandRanbinLiuDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPublishedbyIWAPublishingUnit104–105,ExportBuilding1CloveCrescentLondonE142BA,UKTelephone:+44(0)2076545500Fax:+44(0)2076545555Email:publications@iwap.co.ukWeb:www.iwapublishing.comFirstpublished2024©2024IWAPublishingApartfromanyfairdealingforthepurposesofresearchorprivatestudy,orcriticismorreview,aspermittedundertheUKCopyright,DesignsandPatentsAct(1998),nopartofthispublicationmaybereproduced,storedortransmittedinanyformorbyanymeans,withoutthepriorpermissioninwritingofthepublisher,or,inthecaseofphotographicreproduction,inaccordancewiththetermsoflicensesissuedbytheCopyrightLicensingAgencyintheUK,orinaccordancewiththetermsoflicensesissuedbytheappropriatereproductionrightsorganizationoutsidetheUK.EnquiriesconcerningreproductionoutsidethetermsstatedhereshouldbesenttoIWAPublishingattheaddressprintedabove.Thepublishermakesnorepresentation,expressorimplied,withregardtotheaccuracyoftheinformationcontainedinthisbookandcannotacceptanylegalresponsibilityorliabilityforerrorsoromissionsthatmaybemade.DisclaimerTheinformationprovidedandtheopinionsgiveninthispublicationarenotnecessarilythoseofIWAandshouldnotbeacteduponwithoutindependentconsiderationandprofessionaladvice.IWAandtheEditorsandAuthorswillnotacceptresponsibilityforanylossordamagesufferedbyanypersonactingorrefrainingfromactinguponanymaterialcontainedinthispublication.BritishLibraryCataloguinginPublicationDataACIPcataloguerecordforthisbookisavailablefromtheBritishLibraryISBN:9781789064223(eBook)Doi:10.2166/9781789064223ThiseBookwasmadeOpenAccessinFebruary2024.©2024IWAPThisisanOpenAccessbookdistributedunderthetermsoftheCreativeCommonsAttributionLicence(CCBY-NC-ND4.0),whichpermitscopyingandredistributionfornon-commercialpurposeswithnoderivatives,providedtheoriginalworkisproperlycited(https://creativecommons.org/licenses/by-nc-nd/4.0/).Thisdoesnotaffecttherightslicensedorassignedfromanythirdpartyinthisbook.Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestContentsListofContributors...........................................................................................................ixForeword.........................................................................................................................xiPreface..........................................................................................................................xiiiAcknowledgements.........................................................................................................xvChapter1Generalprinciples.............................................................................................11.1Purposes....................................................................................................................11.2Applicationscope........................................................................................................1Chapter2Urbanwatersectorsandtheircarbonemissions.................................................32.1Urbanwatersectors....................................................................................................32.2Carbonemissionsofurbanwatersectors.....................................................................42.2.1Greenhousegasesandglobalwarmingpotential..............................................42.2.2Reportingboundariesandemissionactivities....................................................4Chapter3Carbonaccountingprinciplesandmethodologies...............................................113.1Basicprinciples..........................................................................................................113.2Accountingprocedures...............................................................................................113.2.1Generalintroduction.......................................................................................113.2.2Watercompanies..........................................................................................123.2.3Watersectorassociations..............................................................................133.2.4Waterdepartments........................................................................................133.3Accountingmethodologies.........................................................................................133.3.1Generalintroduction......................................................................................133.3.2Watercompanies..........................................................................................153.3.3Watersectorassociations..............................................................................213.3.4Waterdepartments........................................................................................21Chapter4Planningandconstruction................................................................................234.1Overview..................................................................................................................23Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector4.2Directemissionsoffossilfuel.....................................................................................234.3Indirectemissionsfromelectricityconsumption...........................................................244.4Indirectemissionsfrommaterialconsumption.............................................................244.5Indirectemissionsfromtransportation........................................................................244.6Overallestimationasawhole.....................................................................................254.6.1Estimationbasedonwatervolumehandled....................................................254.6.2Estimationbasedoninvestment.....................................................................31Chapter5Operationandmaintenance.............................................................................355.1Overview..................................................................................................................355.2Generalprovisions....................................................................................................355.2.1Directemissionsoffossilfuel.........................................................................355.2.2Indirectemissionsfromelectricityconsumption...............................................355.2.3Indirectemissionsofmaterialconsumption.....................................................365.2.4Indirectemissionsoftransportation................................................................365.3Watersupplysystems................................................................................................375.3.1Accountingboundary.....................................................................................375.3.2Waterabstractionfacilities.............................................................................405.3.3Watertreatmentplants..................................................................................405.3.4Desalinationplants........................................................................................415.3.5Waterdistributionnetwork.............................................................................425.3.6Long-distancewatertransfer..........................................................................425.4Wastewatermanagementsystems.............................................................................435.4.1Accountingboundary.....................................................................................435.4.2Wastewatercollectionnetworks.....................................................................465.4.3Wastewatertreatmentplants.........................................................................505.4.4Sludgetreatmentanddisposal.......................................................................575.5Waterreclamationsystems........................................................................................615.5.1Accountingboundary.....................................................................................615.5.2Advancedtreatmentplants............................................................................635.5.3Waterdistributionnetwork.............................................................................635.6Stormwatersystems..................................................................................................635.6.1Accountingboundary.....................................................................................635.6.2Stormwatersewers.......................................................................................665.6.3Stormwatercontrolfacilities...........................................................................67Chapter6Assetreplacementanddemolition....................................................................716.1Overview..................................................................................................................716.2Directemissionsoffossilfuel.....................................................................................71viDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestContents6.3Indirectemissionsfromelectricityconsumption...........................................................726.4Indirectemissionsoftransportation............................................................................726.5Carbonoffsetviamaterialrecovery............................................................................73Chapter7Carbonreductionpathwaysinurbanwatersectors............................................757.1Overview..................................................................................................................757.2Synergyofsubsystems’carbonemissionreductioninurbanwatersectors...................817.3Planningandconstructionandassetreplacementanddemolition................................847.3.1Overview......................................................................................................847.3.2Carbonreductionpathways...........................................................................887.3.3Carbonreplacementpathways.......................................................................907.4Watersupplyandwaterreclamationsystems..............................................................907.4.1Overview......................................................................................................907.4.2Carbonreductionpathways...........................................................................947.4.3Carbonreplacementpathways.......................................................................947.5Wastewatermanagementsystems.............................................................................957.5.1Overview......................................................................................................957.5.2Carbonreductionpathways..........................................................................1007.5.3Carbonreplacementpathways......................................................................1027.6Stormwatersystems.................................................................................................1037.6.1Overview.....................................................................................................1037.6.2Carbonreductionpathways..........................................................................1077.6.3Carbonreplacementpathways......................................................................1087.6.4Carbonremovalpathways............................................................................109Chapter8Dataacquisitionandmanagement..................................................................1118.1Overview.................................................................................................................1118.2Activitydataacquisition.............................................................................................1118.3Emissionfactorsacquisition......................................................................................1228.3.1Generalemissionfactors..............................................................................1228.3.2CH4andN2Oemissionfactorsinwastewatermanagementsystems...............124Chapter9Resultinterpretatonandreporting...................................................................1319.1Resultinterpretation.................................................................................................1319.1.1Keyinformationanalyzed.............................................................................1329.1.2Analyzingmethodologies..............................................................................1339.2Reportingprotocol....................................................................................................1379.2.1Informationofreportingentity.......................................................................1379.2.2Datasources...............................................................................................1379.2.3Emissionfactors..........................................................................................137viiDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector9.2.4Carbonemissions........................................................................................137AppendixATermsandsymbols......................................................................................139AppendixBEmissionfactors..........................................................................................143AppendixCConstructioninventoryandintegratedemissionfactorformulation..................159AppendixDCarbonaccounting:casestudies..................................................................195AppendixECarbonemissionreductionpotentialoftypicaltechnologies............................221AppendixFReportingprotocol........................................................................................231References....................................................................................................................237viiiDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestListofcontributorsEditor-in-ChiefXiaodiHaoisafullprofessorinthefacultyofEnvironmentandEnergyEngineeringatBeijingUniversityofCivilEngineeringandArchitecture/China.HeacquiredhisPhDdegreefromDelftUniversityofTechnology(TUDelft)intheNetherlands.Dr.HaoleadstheSino-DutchRandDCentreforFutureWastewaterTreatmentTechnologies,focusingonbiologicaltreatmentandresource/energyrecoveryfromwastewater.Dr.HaoworkedintheNetherlands(TUDelftandTNO),France(CEMAGREF),HongKong(Poly-UandUST),UnitedStates(AuburnUniversity),Japan(GifuUniversity)for7years.HeisaneditorofWaterResearch.RanbinLiuisanassociateprofessorinthefacultyofenvironmentandenergyengineeringatBeijingUniversityofCivilEngineeringandArchitecture,China.HeobtainedhisPhDdegreefromUniversityCollegeDublin,Irelandandiscurrentlyworkingonoptimizationofbiologicalphosphorusremoval,decarbonizationofthewatersector,andalgae-basedwastewatertreatments.AssociateEditorEditingMembers:HuiminLi1ShuangLi2JianxinZhang3QingyuanTong4WenboYu1XiuhengWang6ShiheZhang7FujingLi2JunqiLi1HeqingZhang4DaqiCao1ShanshanHe5ZhengshuWang2JunZhang5JinqiYu4RanCai2DaweiYao3YuanyuanWu2YuBai3YaoLiu3EditingOrganizations:1.BeijingUniversityofCivilEngineeringandArchitecture2.BeijingCapitalEco-EnvironmentalProtectionGroupCo.,Ltd.ixDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector3.BeijingUrbanDrainageGroupCo.,Ltd.4.CSCECSCIMEESci.andTech.Co.,Ltd.5.CentralandSouthernChinaMunicipalEngineeringDesignandResearchInstituteCo.,Ltd.6.HarbinInstituteofTechnology7.ChinaUrbanWaterAssociationxDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestForewordInSeptember2020,atthe75thsessionoftheUnitedNationsGeneralAssembly,PresidentXiJinpingsolemnlypledgedthatChinawillstrivetopeakcarbondioxideemissionsbefore2030andachievecarbonneutralitybefore2060,i.e.dualcarbongoals.Thismajorstrategicdecisionwasbasedonoursenseofresponsibilityinbuildingacommunitywithasharedfutureformankindandourownneedtosecuresustainabledevelopment.TheCentralCommitteeoftheCommunistPartyofChinaandtheStateCouncilreleasedadocumenttitled"WorkingGuidanceforCarbonDioxidePeakingandCarbonNeutralityinFullandFaithfulImplementationoftheNewDevelopmentPhilosophy".Togetherwiththe“ActionPlanforCarbonDioxidePeakingBefore2030”and“ImplementationPlanforSynergizingtheReductionofPollutionandCarbonEmission”,Chinaformulateda“1+N”policyframeworktoguidethesedualcarbongoals.Fromtheperspectiveoftop-leveldesign,thedualcarbongoalshavebeenbrokendownonebyone,anddirectionshavebeenestablishedforthedevelopmentandtransformationofallindustriesandcarbonemissionreductionactions.Asanimportantpartofurbaninfrastructure,ensuringthenormallifeofresidentsandthehealthydevelopmentoftheeconomy,urbanwatersectorsareakeyfactorinthesustainabledevelopmentofChinesecities.Sincetheimplementationofreformandopeningup,China'surbanwatersupplyhascontinuedtogrowanddevelop,withtheconstructionandservicecapabilitiesofwatersupplyanddrainagefacilitieshavingimprovedyearbyyear,andtheproductioncapacityandutilizationofreclaimedwaterreachingarecordhigh.Inresponsetotheextremerainfallbroughtaboutbyclimatechange,Chinaisalsoactivelypromoting“spongecities”andimprovingtheplanningandconstructionofurbanwaterloggingpreventionandcontrolfacilities.However,China'surbanwatersectorsarealsofacingthehugechallengesofbeinglabeledaslargeenergyconsumers.Accordingtopreliminarystatisticsandestimates,thepowerconsumptionoftheurbanwatersupplysystemaloneaccountsforabout1.5%ofthewholestate'spowerconsumption.Moreover,duetothelowefficiencyofurbansewagetreatmentsystems,effluentqualityisonlyabletomeetthedischargingstandardatthecostoftheconsumptionofenergyandchemicals.Consequently,theaboveactivitiescausegreatlyincreasedgreenhousegasemissions.WiththecontinuousurbanizationofChinaleadingtourbanwatersupplyanddrainagecapacitiesincreasingyearbyyear,coupledwithincreasingstressontheecologicalenvironment,itisforeseeablethattheenergyconsumptionandcarbonemissionsoftheurbanwatersectorwillinevitablyincreaseunlesseffectivestepsaretakenswiftly.Underthepressureofdualcarbongoals,theurbanwaterxiDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorsectorsarefacingenormouschallengesintermsoftechnologicalinnovationandupgrading.However,thesechallengesmayalsoprovideopportunities.Drivenbythemultiplegoalsofimprovingtheecologyoftheurbanwatersector,environment,resourcesandsafety,theurbanwatersectormustreducepollutionandcarbonemissions,leveragetheirsynergytoachievelow-carbonandgreen,andsetitselfonamoresustainablecourse.Recently,sevenministriesofthePRC,includingtheMinistryofEcologicalEnvironment,jointlyissuedthe“ImplementationPlanforSynergizingtheReductionofPollutionandCarbonEmission”.Init,theyproposedto"carryoutcarbonemissionmeasurementforurbansewagetreatmentandresourceutilization,andoptimizetheenergyconsumptionandcarbonemissionmanagementofsewagetreatmentfacilities".ThisshowsthatChina'sreductionincarbonaccountingandemissionshasgraduallyevolvedfromheavyindustrieswithhighcarbonemissionstoroutinelifeandservicebusinesses.Citiesandtownshavebeenincludedinthestruggletoreducepollutionandcarbonemissions.Therefore,theurbanwatersectorcannotbeexcluded;indeed,itisimperativethatChinatakesswiftactiontoreducecarbonemissionsandachievelow-carbondevelopment.Carbonaccountingisthefirststepfortheindustrytocarryoutlow-carbondevelopmentandclarifytheentanglementbetweencarbonemissionandprofits,i.e.,high-carboncoupledwithadeficit,low-carbonreversingdeficit,andcarbonnegativeleadingtoprofits.Thereisawiderangeofcomplexcarbonemissionactivitiesintheurbanwatersector,andthereisnogeneralagreementonastandarddefinitionoftheiraccountingboundaries.Inparticular,theunclearidentificationofgreenhousegasemissionactivitiesleadstoomission,overcalculation,andmiscalculation,whichisnotconducivetotherecognitionandconsensusoncarbonemissionintheurbanwatersectors,aswellastoidentifyingthekeypointstoreducecarbonemissions.Basedonthis,theChinaUrbanWaterAssociationorganizedthecompilationoftheGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector(hereinafterreferredtoastheGuidelines).ThisGuidelinesfocusesonclarifyingtheboundariesandmethodsofcarbonaccountingofurbanwatersectorsunderthedualcarbongoals,analyzingandcategorizingcarbonemissionpathsandstrategies.ItisbelievedthatthereleaseoftheGuidelineswilldefinitelypromotethepracticeofthedualcarbongoalsactionintheurbanwatersectors,helptomeettheresponsibilitiesandobligationsoftheindustryandmakecontributionstothedevelopmentofChinaasagreenandlow-carbonsystem.LinweiZhangPresidentofChinaUrbanWaterAssociationxiiDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPrefaceChina'sstrivingtoachievecarbonpeakingby2030andcarbonneutralityby2060arecriticalstrategicdecisionsmadebytheCentralCommitteeoftheCommunistPartyofChina.TheyarerelatedtothesustainabledevelopmentofChinaaswellastothebuildingofaCommunityofSharedFutureforhumanity.TheyalsodemonstrateChina'sfirmdeterminationtoactivelyrespondtoclimatechangeandtakethehigh-qualitydevelopmentpathofprioritizingtheecology,greentransformation,andlowcarbonemissions.TheCentralCommitteeoftheCommunistPartyofChinaandtheStateCouncilsuccessivelyissued“WorkingGuidanceforCarbonDioxidePeakingandCarbonNeutralityinFullandFaithfulImplementationoftheNewDevelopmentPhilosophy”,“ActionPlanforCarbonDioxidePeakingBefore2030”,and“ImplementationPlanforSynergizingtheReductionofPollutionandCarbonEmission”.ThesedocumentswillhelpChinaachieveacomprehensivegreentransformationofeconomicandsocialdevelopmentthroughthedualcarbongoalsbyindicatingthedirectiontotakeandprovidingablueprintforsuccessfuldevelopment.Toensuretherealizationofthesedualcarbongoals,"establishingaunifiedandstandardizedcarbonemissionaccountingsystem"hasbeenlistedasanimportanttask.The“ActionPlanforCarbonDioxidePeakingBefore2030”clearlyhighlightsthat"strengtheningthecapacity-buildingofcarbonemissionstatisticalaccounting,deepeningtheresearchonaccountingmethods,acceleratingtheestablishmentofaunifiedandstandardizedcarbonemissionstatisticalaccountingsystem,supportingindustriesandenterprisestocarryoutcarbonemissionandalgorithmmethodologyresearchaccordingtotheircharacteristics,andestablishingthecarbonemissionmeasurementsystem".Theurbanwatersectoristhebasicfoundationofdailylifeforurbanresidents,andthelifelinetomaintainingurbanrunning.Italsointersectswithmanyotherareasofthenationaleconomy,whichmakescarbonemissionactivitiescomplex.Inrecentyears,agreatdealofresearchhasbeencarriedoutonthecarbonemissionsofurbanwatersectors,providingimportantsupportforthedevelopmentoflow-carbonpractices.Toalignwiththe“WorkingGuidanceforCarbonDioxidePeakingandCarbonNeutralityinFullandFaithfulImplementationoftheNewDevelopmentPhilosophy”andthe“ActionPlanforCarbonDioxidePeakingBefore2030”,takealeadingroleinindustryassociations,andacceleratetheestablishmentofaunifiedandstandardizedcarbonemissionaccountingsystem,theChinaUrbanWaterAssociationorganizedthepreparationoftheGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectors(hereinafterreferredtoastheGuidelines)toguidethesectorsincarryingoutcarbonemissionreduction.TheGuidelinesconsistsof10chapters,includinggeneralprinciples,urbanwatersectorsandcarbonemissions,carbonaccountingprinciplesandmethodologies,planningandconstruction,operationandmaintenance,assetreplacementanddemolition,carbonemissionreductionpathwaysofurbanwaterxiiiDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorsectors,dataacquisitionandmanagement,interpretationofresultandreporting,andtheappendices.TheGuidelinesregulatesthecarbonemissionaccountingmethodsinawholelifecyclebydividingtheurbanwatersectorsintofoursubsectors:watersupplysector,sewagesector,reclaimedwatersector,andrainwatermanagementsector.TheGuidelinesbeginsbyclarifyingthecarbonemissionactivitiesofeachsubsector,thenunifiesthecarbonemissionaccountingboundary,givestransparentcarbonemissionfactorsandfinallyunifiesthecarbonemissionaccountingandreportingtemplate.Toguidecarbonemissionreductionintheurbanwatersector,theGuidelinesproposesstrategiesforcarbonemissionreductioninurbanwatersystemsinthefollowingfiveareas:sourcecontrol,processoptimization,technologyupgrades,renewableenergy,andcarbonsinks.Overall,theGuidelineshighlightsthefollowingfeatures:Scientificity.Theaccountingprinciples,accountingframework,andaccountingmethodsfollowtheestablishedgreenhousegasaccountingsystem,i.e.,“GreenhouseGasProtocol”and“Greenhousegases—Part1:Specificationwithguidanceattheorganizationlevelforquantificationandreportingofgreenhousegasemissionsandremovals(ISO14064-1:2018)”,reflectingthescientificconsensus.Consistency.Carbonemissionfactorscomefromgovernmentalopen-accessdataand/orscientificliterature,particularlylocaldocuments,andreflectthetransparencyoftheaccountingprocessandtheaccuracyoftheaccountingresults.Modularization.TheGuidelinesprovidesaccountingmethodsintermsoffoursubsectors–thewatersupplysector,thesewagesector,thereclaimedwatersector,andtherainwatermanagementsector–aswellasthreelifecyclestages(planningandconstruction,operationandmaintenance,andassetreplacementanddemolition)withatotalof12modules.Thesecanbeflexiblyappliedtocarbonemissionaccountingfordifferentpurposes.Comprehensiveness.TheGuidelinescoversallcarbonemissionactivitiesthroughoutthelifecycleoftheurbanwatersectors.Italsoprovidescarbonemissionreductionpathwaysofdifferentsubsectors,whichcanbeusedforcarbonemissionaccountingbydifferentoperatingentitiesaswellasforcarbonemissionreductionpathwayanalysis.Hierarchy.TheGuidelinesprovidesvariousaccountingmethodsandemissionfactorsbasedontheavailabilityofdata,whichcanbeflexiblyselectedaccordingtoaccountingpurposes.Guidance.TheGuidelinesstandardizesthecarbonemissionaccountingprocess,outlinestheemissionreductiontechnologyandstrategyofeachsubsector,unifiesthecarbonemissionaccountingreport,andillustratestheguidanceroleoftheindustryassociationonthedevelopmentofthewatersector.ThecompilationoftheGuidelineswasledbytheBeijingUniversityofCivilEngineeringandArchitecture,togetherwithBeijingCapitalEco-EnvironmentalProtectionGroupCo.,Ltd.,BeijingUrbanDrainageGroupCo.,Ltd.,CSCECSCIMEESci.andTech.Co.,Ltd.,CentralandSouthernChinaMunicipalEngineeringDesignandResearchInstituteCo.,Ltd.,andHarbinInstituteofTechnology.InthepreparationoftheGuidelines,theChinaUrbanWaterAssociationheldseveralexpertconsultationmeetingstosolicitopinionsfromvariousparties.Onthisbasis,thefirsttechnicalguidelinesforcarbonaccountingandemissionreductionpathwaysoftheurbanwatersectorwereoutlined.IfanyfurtherstrategiesorinformationaredevelopedordeemednoteworthyforthepurposesofcorrectingorenhancingtheGuidelines,pleasedonothesitatetocontactussothatthecompilationgroupmayupdateandimprovetheirinformation.Guidelines’editingteamJuly2022xivDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAcknowledgementsWewouldliketoexpressoursincerethankstoallthereviewerslistedbelowfortheirtimeandeffortsinreviewingthisbook.JiuhuiQu(AcademicianofChineseAcademyofEngineering),TsinghuaUniversityNanqiRen(AcademicianofChineseAcademyofEngineering),HarbinInstituteofTechnologyLi’anHou(AcademicianofChineseAcademyofEngineering),TheHJJUniversityofEngineeringYongzhenPeng(AcademicianofChineseAcademyofEngineering),BeijingUniversityofTechnologyJunMa(AcademicianofChineseAcademyofEngineering),HarbinInstituteofTechnologyZuxinXu(AcademicianofChineseAcademyofEngineering),TongjiUniversityHongchunZhou,DevelopmentResearchCenteroftheStateCouncilofChinaYiLi,BeijingGeneralMunicipalEngineeringDesignandResearchInstituteCo.,Ltd.ShuyuanLi,CentralandSouthernChinaMunicipalEngineeringDesignandResearchInstituteCo.,Ltd.XiaojiaHuang,ChinaIPPRInternationalEngineeringCo.,Ltd.JinsongZhang,ShenzhenWater(Group)Co.,Ltd.SpecialthanksaregiventoProf.MarkvanLoosdrechtforhispromotionoftheEnglishversionofthisbookandalsotoMr.RowanKohllforpolishingouruseofEnglishgrammarandwritingstyle.ThisworkwaspartlysupportedbytheNationalNatureScienceFoundationofChina(52170018).xvDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter1Generalprinciples1.1PURPOSESTheobjectivesoftheseGuidelinesaretoclarifycarbon(orgreenhousegas,GHG)accountingboundaries,carbonemissionactivitiesandcarbonemissioncategoriesintheurbanwatersector.Theyalsoservetostandardizedataacquisitionandcarbonaccountingmethodologies;tohelpnavigateaccountingimplementationinascientificmanner;andtoregulatecarbonemissionreporting.Inaddition,theGuidelinessummarizethestrategiesandactionsthatcanachievecarbonreductioninthewatersector;promotetheroleofcarbonaccountingandreductioninleveragingsustainablemanagementoftheurbanwatersector;andstrengthentop-leveldesigntoguidethemovetowardslowcarbondevelopmentofthewatersector.1.2APPLICATIONSCOPEGuidelinesisapplicabletothecarbonaccountingandreportingofurbanwatersectorsinChina,andcanalsobereferredtowhenformulatingandimplementingcarbonreductionplansandactions,whichcaninclude:Guidingthewaterutilitiestorecognizeandclarifytheirboundaries,activitiesandcategoriesofcarbonemissions,andservingasabasicframeworkforformulatingcomprehensivepoliciesand/orplansforcarbonmanagement;Instructingurbanwatersectorstoimplementcarbonaccountingoverthecourseofalifecycle(planningandconstruction,operationandmaintenance,andassetreplacementanddemolition)and/orforspecificemissionactivities;Guidingtheurbanwatersectorstoanalyzecarbonaccountingresultsand,basedontheseresults,carryingouttop-leveldesignofcarbonreductionactions,programdevelopment,strategyimplementation,evaluationfeedback,andinterdepartmentalcollaboration.1Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter2Urbanwatersectorsandtheircarbonemissions2.1URBANWATERSECTORSTheseGuidelinesaimaturbanwatersectorsforcarbonaccountingfocusingonfourmainsystems–watersupplysystems,wastewatermanagementsystems,waterreclamationsystemsandstormwatermanagementsystemsasshowninFigure2.1.Watersupplysystemsconsistoffivemodules:waterabstraction,watertreatmentplants,seawaterdesalinationplants,waterdistributionnetworks,andlong-distancewaterconveyance.Wastewatermanagementsystemsconsistsofthreemodules,wastewatercollectionnetworks(includingseptictanks),wastewatertreatmentplants,andsludgetreatmentanddisposalfacilities.Waterreclamationsystemsconsistsoftwomodules:advancedtreatmentplantsandwaterdistributionnetworks.Stormwatersystemsconsistsoftwomodulesofstormwatersewersandstormwatercontrolfacilitiesthatstore,infiltrate,orreusestormwaterandreduceflowstosewersystemsortosurfacewaters.3Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure2.1SchematicdiagramofurbanwatersectorstargetedintheseGuidelines.2.2CARBONEMISSIONSOFURBANWATERSECTORS2.2.1GreenhousegasesandglobalwarmingpotentialThetypesofgreenhousegases(GHG)consideredinGuidelinesincludecarbondioxide(CO2),methane(CH4),andnitrousoxide(N2O).AccordingtotheInternationalstandardofISO14064-1:2018(ISO,2018),GHGemissionaccountingisthoughttoutilizeGlobalWarmingPotential(GWP)with100-yeartimesspanasshowninthereferencestandard(Table2.1).Table2.1Globalwarmingpotential(GWP)valuesrelativetoCO2(IPCC,2013).GHGGWP100CH428N2O2652.2.2ReportingboundariesandemissionactivitiesThewatersectorsshouldestablishanddocumenttheiraccountingboundaries(reportingboundaries)toensuretheaccuracyandrepresentativenessofcarbonaccountingresults.Thisisalsoimportantforresult4Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestUrbanwatersectorsandtheircarbonemissioninterpretationandcomparisonanalysis.Besides,accountingboundariesconsistofmultipledimensionswhichisalsoadetrimentalfactorfortheemissionquantificationresults.Thus,inthisGuidelines,timerange(temporaldimension)andtheinteractionboundarybetweensystemandnature(spatialdimension)arethemostbasictwodimensionswithinwhichthecarbonemissionaccountingmethodofurbanwatersectorsaredeveloped.Intermsoftimerange,carbonemissionoccursinassociationwiththelifecycleoftheconstruction,operation,anddemolitionofstructuresandbuildingsinthewatersectors.Fromtheperspectiveofcarbonreduction,agreatdealofworkcanbedoneateverystageofthelifecycleinordertoachievecarbonreduction.Thus,thecarbonaccountingandreductionintheurbanwatersectorissupposedtoconsideritswholelifecyclefromcradletograve(Figure2.2),namely:1)planningandconstruction,thewholeprocessprecedingtheformaloperationofthefacility;2)operationandmaintenance,theentireprocessfromtheformaloperationtoend-of-run;3)assetreplacementanddemolition,theentireprocessofusingthefacilityforotherpurposesorcompletelyremovingitaftertheendofitsoperationallifespan.Intermsofthespatialboundary,carbonaccountinginurbanwatersectorsincludesnotonlyGHGemissionwithintheorganizationalboundaryoftheurbanwatersector,butalsorelatedmaterialflowandotheractivities,suchasenergyinput,effluentdischargeandsludgedisposal,allofwhichareaddressedbelowindetail.Figure2.2Temporalboundaryofcarbonemissionaccountinginurbanwatersector.Toensuretheresultsareeasytoreadandinterpret,thereportingboundariesareinlinewiththeinternationalstandardsoftheGreenhouseGasProtocol(WBCSD/WRI,2004)andGreenhousegas-Part1:Specificationwithguidanceattheorganizationlevelforquantificationandreportingofgreenhousegasemissionsandremovals(ISO14064-1:2018)(ISO,2018).IntheGreenhouseGasProtocol,theGHGemissionsareclassifiedintothreescopes(Table2.2):Scope1:directGHGemissionsproducedatfacilitiesand/orassetsownedbythewatersectors;Scope2:indirectGHGemissionsincurredbyanenergyproviderwhenproducingtheenergypurchasedbythewatersectors;Scope3:otherindirectGHGemissionsnotattributabletoenergy,includingemissionsgeneratedbytheproductionsofgoods,transportation.Bycontrast,ISO14064-1:2018standarddividesthreescopesintosixcategories,whichare:1)directGHGemissionsandremovals;2)indirectGHGemissionsfromimportedenergy;3)indirectGHGemissionsfromtransportation;4)indirectGHGemissionsfromproductsusedbytheorganization;5)indirectGHGemissionsassociatedwiththeuseofproductsfromtheorganizations;6)indirectGHGemissionsfromothersources.AssummarizedinTable2.2,thesetwokindsofclassificationsare5Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorconsistent.Next,accordingtotheabove-mentionedclassificationmethods,theGHGemissionactivitiesofurbanwatersectorsaresummarizedinto5groups(Table2.2):Emissionfromtheconsumptionoffossilfuelswithintheorganizationalboundariesandemissionintheproductionoftheimportedenergyinawholelifecycle;Emissionsfromtheproductionofgoodsconsumedbythewatersectorsinthewholelifecycle,suchasbuildingmaterialsandchemicals;Emissionsfromthetransportationforbuildingmaterials,chemicals,byproductsexported,andbuildingwasteinassetreplacementanddemolition;Emissionsfromthebiologicalprocessesoccuringinwastewatercollection,treatmentorsludgetreatmentanddisposalandinCSOeventsandeffluentdischarge;Carboncreditsfromresourcesrecovery,renewables,andvegetationsequestrations.ItisnoteworthythatseveralsourcesofGHGemissionsintheurbanwatersectorspecifiedinthisGuidelinesareexplicitlyexcluded,including:BiogenicCO2Accordingtodifferentsourcesoforganicmatter,theCO2canbedividedintobiogeniccarbon(BC)andfossilcarbon(FC)(Isaksen,2012).Fromtheperspectiveofthecarboncycle,iftheycanbetracedtotheorganicmattergeneratedbyplantphotosynthesis,theyarereferredtoasbiogenicCO2.Becausetheycomefromtheatmosphericcarbonpool,whichtheyalsoeventuallyreturnto,andbecausetheyareintheearth'sshort-termcarboncycle.Therefore,biogenicCO2doesnotresultinanetincreaseofthetotalamountofCO2intheatmosphere.Ontheotherhand,iftheorganicmatterisultimatelytracedbacktofossilfuelsortheirconvertedproducts,theproducedCO2isdefinedasfossilCO2(ornon-biogeniccarbon).sinceitbelongstothelong-termcarboncyclerepresentedbyfossilfuels.Intermsofwastewatermanagementsystem,asmallfractionofcarboncomesfromfossilsources(i.e.,somecomponentsofcosmeticsandskincareproducts).Therefore,thefossil(ornon-biogenic)CO2iscountedintheaccountingboundaries.ItshouldbeemphasizedthattheCH4producedbyincompletemineralizationofbiogeniccarbonshouldalsobeincludedincarbonemissionaccounting.GHGemissionsfromindustrialwastewatertreatmentfacilitiesbeforedischargeintourbansewagesystemsIndustrialwastewater,isrequiredtomeetqualitystandardsbeforebeingdischargedintourbanwastewatercollectionsystemsasindicatedbytheWaterQualityStandardsforDischargeofSewageintoUrbanSewers(GB/T31962-2015)(GB/T31962-2015,2015).TreatmentfacilitiesaregenerallybuiltandoperatedbyindustriesthemselvesandnotincludedintheorganizationalboundariesofthewatersectorsinthisGuidelines.Besides,industrialwastewaterisdifferentfromdomesticwastewaterintermsofbothcompositionandtreatmentprocesses.Thecarbonemissionaccountingmethodsusedfordomesticwastewatercannotbeadopteddirectlyforindustrialwastewater.Therefore,thecarbonemissionsfromindustrialwastewatertreatmentfacilitiesarenotincludedinthisGuidelines.6Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestUrbanwatersectorsandtheircarbonemissionSecondarywatersupplystationsInthewatersupplysystem,waterdistributionnetworksareisdesignedtoconveyenoughwatervolumeandpressureforconsumersbypumps.Insomecases,thepressureprovidedbythemunicipallevelpublicwatersupplycannotmeetthedemandofsomehigh-risingbuildings.Thus,asecondarywatersupplystationisoftenadoptedwithboosterpumpswhichleadtoanincreaseofenergyconsumptionandGHGemissions.Atpresent,thesecondarywatersupplystationisgenerallychargedbycertifiedproperties.Overall,theGHGemissionsofsecondarywatersupplystationsareexcludedinthisGuidelines.Itshouldbenotedthatifthejurisdictionofthesecondarywatersupplystationschanges,theirinclusioninthereportingboundariesofurbanwatersectorswillneedtobereconsidered.7Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable2.2SummaryofGHGemissionactivitiesoftheurbanwatersector.Scope(GHGCategory(ISO14064-1:WaterWastewatermanagementsystemWaterStormwaterProtocol)2018)supplyreclamationsystemsystemDirectGHGDirectGHGemissionsorsystememissionsfromcarbonsinksactivitieswithintheGHGemissionscausedbyoil,coal,andgasenergyconsumedonsiteateachstageofthefulllifecyclemanagementboundaryoftheNon-biogenicCO2,CH4andN2OproducedbybiochemicalGHGemissionsaccountingentityfromstormwater—reactionsinsewagecollection,in-planttreatmentorsludge—IndirectGHGemissionsduetoin-planttreatmentwetlandunitselectricity,steam,heating/coolingGreensourcesOtherindirectGHG—Carboncompensationintheformofresourceandenergy—stormwateremissionscausedbyrecoveryfacilitycarbontheactivitiesoftheaccountingsubjectsinkbutoutsidethemanagementIndirectGHGemissions-GHGemissionscausedbyelectricityandthermalenergyconsumedonsiteateachstageofthelifecycleelectricityandheatconsumptionIndirectGHGemissions-GHGemissionsateachstageofthelifecycleduetothematerialsusedandthemeansoftransportationusedtransportforoff-sitedisposalofwasteIndirectGHGemissions-materialinputsandservicesGHGemissionsfrompurchasedandconsumedmaterialsateachstageofthelifecycleIndirectGHGemissions-assetandBy-Productdisposal1GHGemissionsgeneratedduringoff-sitedisposalofmuddywaterorsludgegenerated—duringwaterqualitytreatmentContinued8Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestUrbanwatersectorsandtheircarbonemissionScope(GHGCategory(ISO14064-1:WaterWastewatermanagementsystemWaterStormwaterProtocol)2018)supplyreclamationsystemsystemsystemboundaryoftheCO2,CH4andN2Oproducedbycombinedsystemoverflowaccountingsubject,—(CSO)pollutionandeffluentdischargedintothereceiving——suchaspurchasedwaterbodybiochemicallyconsumables,wasteIndirectGHGemissions-other————disposal1.ItmainlycoverstheGHGemissionscausedbythereactionofcarbonandnitrogencontainedintheby-productsthemselveswhentheseby-productsproducedbyeachsystem(forexample,sludge)aretransportedtotheoutsideofthemanagementboundaryfordisposal.However,emissionsfromnormalactivitiesofotheroperatingentitiesmainlyengagedinwastetreatmentarenotincluded.Forexample,theresidualsludgeofasewagetreatmentplantistransportedtoalandfillafterin-planttreatment(stabilizeddehydration,etc.),andthecarbonbiochemicalreactioncontainedinthegeneratedCH4shouldbecountedbuttheGHGgeneratedbynormaloperationssuchaslandfillsarenotcounted.9Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter3Carbonaccountingprinciplesandmethodologies3.1BASICPRINCIPLESTheapplicationofprinciplesisthekeytoensuretrueandfairofaccounting,aswellasbeingimportantininterpretingandanalyzingtheresults.Theprincipleswhicharethebasisformakinganaccountingplanandimplementingaccountingpracticeswhichare(ISO,2018):•Correlation:Allactivitiesrelatedtogreenhousegas(GHG)emissionsintheurbanwatersectorshouldbeincludedintheaccountingboundarytoensurethattheaccountingresultstrulyrepresentthelevelofGHGemissions.•Integrity:Allemissionactivitieswithinthereportingboundariesshouldbeaccountedforandanyexemptionsshouldbeexplicitlystatedandexplained.•Consistency:Theaccountingschemes,boundaries,andmethodsinaninventoryperiodshouldbeconsistent,andanyrevisionsandadjustmentsthatmayaffecttheaccuracyofresultsshouldbeclearlyrecordedandmarked.•Transparency:Datasources,accountingequationsandfactors,andanyassumptionsmademustbeclearlyintroducedanddisplayed.•Accuracy:Measuresshouldbetakentoavoidfoundationaland/orsubjectiveerrorsinaccountingpractices,toreduceuncertainty,andtoensureaccuracy.3.2ACCOUNTINGPROCEDURES3.2.1GeneralintroductionTheoperationandmanagementoftheurbanwatersectorsinvolvemultipleentities,includingthewatercompaniesresponsiblefortheoperationandmaintenanceandthewaterdepartmentsresponsiblefortheregulationsandsupervision.Inaddition,watersectorassociationsalsoplayacriticalroleingroupingcompanies,datacollectionandsharing,formulatinggroupstandards,andensuringthehealthydevelopmentoftheurbanwatersector.Thesectorassociationsnotonlyplaytheroleincollaborationbetweenthewatercompanies,butalsoformabridgebetweenwatercompaniesandthewaterdepartments.Intermsoftheirrolesincarbonaccountingofwatersectors,thesethreeentitiesvaryalotinaccountingboundaries,accountingpurposes,andaccuracyrequirements.AsdepictedinFigure3.1,watercompaniesarethesmallestunitimplementingcarbonaccountingindependently.Insomecases,theaccountingboundariesadoptedbydifferentwatercompaniesareprobablynotconsistent,whichwillinducedifficultiesfortheresultsinterpretationandcomparativeanalysis.Herein,watersector11Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorassociationsandwaterdepartmentscoulddomorebydefiningtheaccountingboundaryandguidingtheaccountingpractice.Then,theaccountingresultsofwatercompaniescanbecollectedandeasytocompilebywatersectorassociationstopresenttheGHGemissionofthewholewatersectorswherebywaterdepartmentsthencouldformulaterelevantpolicymorescientifically.Figure3.1Correlationandrolesofwaterutilities,sectorassociations,andwaterdepartmentsinwatersectorcarbonaccounting.3.2.2WatercompaniesWatercompaniesaretheexecutorsofcarbonaccountingoftheirownedfacilitiesastheyhavethedirectaccesstotheemissionactivitydata.Thekeyissuesforthewatercompaniesaretoensurethedataquality,scientificdeterminationofaccountingboundaries,andrationalityoftheaccountingmethodsasdiscussedabove.Thereinto,sectorassociationsand/orwaterdepartmentscouldplayrolesandprovidethebasicframeworksandguidance.Overall,tomaketheaccountingresultsmoreaccurateandconvincing,watercompaniesarerecommendedtofollowastandardizedprocedureassummarizedbelow.•DeterminetheaccountingboundaryandclarifytheemissionactivitiesandcategoriesofGHGemissions;•Determinetheaccountingmethodsintermsofeachemissionactivityandtherequiredaccountingaccuracy;•Collectandobtaintherequiredactivitydataandemissionfactors,anddoon-sitemonitoringifnecessary;•Implementcarbonaccounting,summarizeandorganizetheaccountingresults,andcalculatethetotalcarbonemissionsandcarbonemissionintensityatthecompanylevel;•Compileandarchivecarbonaccountingreports;•Reporttheresultstothesectorassociationsorwaterdepartments.12Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccountingprinciplesandmethodologies3.2.3WatersectorassociationsTherolesofthewatersectorassociationsincarbonaccountinglieintwoaspects.Oneistoinstructwatercompaniestoimplementaccountingtoavoidinterpretationbias.Theotheristosummarizeandanalyzetheresultssubmittedbywatercompanieswherebythewatersectorassociationscancalculatethetotalemissionandintensityatthesectorlevel.Toensurethequalityandaccuracyofaccountingresultsfromwatercompanies,watersectorassociationsshouldtaketheirroleasfollows:•Coordinatethemembersofwatercompaniestoimplementcarbonaccounting;•Frameaunifiedaccountingboundary,accountingmethod,emissionfactors,etc.;•Guidememberstoobtainactivitydataandtoimplementaccounting•Summarizeandanalyzetheaccountingresultsfrommemberstocalculatetotalcarbonemissionandemissionintensityatsectorlevel(SeeSection3.3.3);•Compileandarchivecarbonaccountingreports;•Sharetheresultswiththewaterdepartments.3.2.4WaterdepartmentsWaterdepartmentsaretakingtheresponsibilityofguidingthewatercompaniestoprovidequalifiedwaterand/orwastewaterservicestoresidents.Besides,itisalsothedutyofwaterdepartmentstopromotethelowcarbondevelopmentofwatercompanies.Assuch,therearealsotworoleswaterdepartmentscouldplayincarbonaccountingofwatersectors.Ontheonehand,waterdepartmentscouldguidewatercompaniestoproceedcarbonaccountingassectorassociationdoes(SeeSection3.2.3).Ontheotherhand,waterdepartmentsalsodocarbonaccountingbythemselvesatacity-leveltosupportgovernmentstodowatersectorplanning.Inmostcases,thelaterscenarioisintheplanninganddecisionmakingstage,andthedatanecessaryforcarbonaccountingshouldbeprovidedbywatercompanies,suchasaverageactivitydataand/oremissionfactors.Overall,watercompaniescanimplementthesecondscenariowiththefollowingsteps:•Mapthewaterflowandbalanceofthewatersectorundervariousplanningschemes,andobtainthenecessaryemissionactivitydata;•Obtainandsummarizetheemissionfactorsforcarbonaccountingbasedontheresultsprovidedbywatersectorassociationsorwatercompanies;•Implementcarbonaccountingandsupportplanningdecisionmaking(SeeSection3.3.4);•Compileandarchivecarbonaccountingreports;3.3ACCOUNTINGMETHODOLOGIES3.3.1GeneralintroductionAsstatedabove,theobtainingofemissionactivitydataisvitallyimportanttotheaccuracyofcarbonaccounting.IntheseGuidelines,avarietyofactivitydataandsourcesareconsidered.Ifthedirectactivitydata(suchaselectricityorfuelconsumption)canbeobtained,carbonaccountingcanbeimplementedbymultiplyingtheactivitydataandtheemissionfactors(Figure3.2,Method1).However,itmaybechallengingtoobtaindirectactivitydatainsomecases,thoughsomeotherrelatedactivitydatacanbeobtainedwhichcanthenbeusedtoobtainthedirectactivitydataandsotocompletethecarbonaccounting-namely,Method2andMethod3(Figure3.2).Itisworthnotingthattheaccuracyofthree13Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectormethodsdiffers,andthatMethod3isconsideredgoodpracticewhileMethod1isthemostaccuratemethodandshouldbegivenpriority.Figure3.2Schematicdiagramofcarbonemissionaccountingmethodsandtheiraccountingaccuracylevels.TheaccountingresultsofGHGemissionsarepresentedasCO2equivalent(CO2-eq)intheseGuidelines.Forcarbonaccountingintheplanningandconstructionandassetreplacementanddemolitionstages,thetotalcarbonemissionsarecalculated.Intheoperationandmaintenancestage,carbonemissionintensityiscalculated.Intermsofcarbonemissionintensity,thewatersupplysystem,wastewatermanagementsystem,andwaterreclamationsystemarecalculatedbasedonthewatervolumehandledintheinventoryyear(plantsarebasedonthetreatmentcapacityandpipenetworksarebasedonwatervolumeconveyed).Regardingthestormwatermanagementsystem,emissionintensityiscalculatedbasedonthevolumeofstormwaterhandledbythemanagementfacilities.ThecarbonemissionandcarbonemissionintensitycanbeconvertedbetweeneachotherasshowninEquation(3.1-3.2):𝐶𝐸=𝐶𝐸𝑆×𝑄×365(3.1)14Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccountingprinciplesandmethodologies𝐶𝐸𝐶𝐸𝑆=𝑄×365(3.2)Where:Totalcarbonemissionsintheinventoryyear,kgCO2-eq𝐶𝐸—Carbonemissionintensityntheinventoryyear,kgCO2-eq/m3𝐶𝐸𝑆—Averagedailytreatedwatervolume,m³/d,watersupplyandsewagetreatmentplants𝑄—aremeasuredbywaterqualitytothestandard,waterdistributionnetworksandsewagepipelinesaremeasuredbytotalwaterconveyancevolumeandrainwater365—sectorsaremeasuredbyconveyanceandmanagementwatervolume365days/year3.3.2WatercompaniesTheemissionactivitiesofwatersectorsandthecorrespondingaccountingmethodindexaresummarizedanddepictedinFigure3.3~Figure3.7.15Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure3.3Relationshiptreeandaccountingindextreeofcarbonemissionactivitiesinthewholelifecycleofwatersupplysystem.16Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccountingprinciplesandmethodologiesFigure3.4Relationshiptreeandaccountingindextreeofcarbonemissionactivitiesinthewholelifecycleofwastewatercollectionnetworks.17Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure3.5Relationshiptreeandaccountingindextreeofcarbonemissionactivitiesinthewholelifecycleofwastewatertreatmentplants.18Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccountingprinciplesandmethodologiesFigure3.6Relationshiptreeandaccountingindextreeofcarbonemissionactivitiesinthewholelifecycleofwastewaterreclamationsystem.19Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure3.7Relationshiptreeandaccountingindextreeofcarbonemissionactivitiesinthewholelifecycleofstormwatermanagementsystem.20Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccountingprinciplesandmethodologies3.3.3WatersectorassociationsAsstatedabove,watersectorassociationscollecttheaccountingresultsfromwatercompaniesandprovideintellectualsupport,e.g.,emissionfactors,forwatersectorplanning.Intermsofthecarbonemissionintensity,itishighlyrelatedtothefacilityscale,treatmentmethod(suchasthemainbiologicaltreatmentunitofsewagetreatmentplant),influentandeffluentwaterquality,etc.Thus,whencalculatingthecarbonemissionintensityfactor,itisrecommendedtoconsidertheabovefactorsifpossible.Iftheresultscannotbegroupedduetoalackofdata,oneemissionfactorcanbecalculatedforeachsystemfollowingEquation(3.3)and(3.4).̅𝐶̅𝐸̅̅𝑆̅=∑𝑛𝑖=1𝐶𝐸𝑖(3.3)∑𝑛𝑄𝑖×365(3.4)𝑖=1̅𝐶̅𝐸̅̅𝑆̅=∑𝑛𝑖=1(𝐶𝐸𝑆𝑖×𝑄𝑖)∑𝑛𝑖=1𝑄𝑖Where:Systemweightedaveragecarbonemissionintensity,kgCO2-eq/m3̅𝐶̅𝐸̅̅𝑆̅—Thefirst𝑖operatingcompany,kgCO2-eq𝐶𝐸𝑖—Ofthefirst𝑖operatingcompany,kgCO2-eq/m3𝐶𝐸𝑆𝑖—Thefirst𝑖operatingenterprise,m3/d,thereferencewaterqualityandvolumeof𝑄𝑖—watersupplyandsewagetreatmentplants,thereferencewatertransfervolumeofwatersupplypipenetworkandsewagepipes,andthereferencetransferandmanagementwatervolumeofrainwatersystem𝑛—Thegroup𝑙runsthebusinesstogetherThepipenetworkisrecommendedtobeclassifiedaccordingtomaterialandpipediameter.Forwatertreatmentplantsandwastewatertreatmentplants,itisrecommendedtogrouptheresultstocalculatespecificemissionfactorasfollows:•Classificationofwatertreatmentplants:scale(<50,000m3/d;5~100,000m3/d;>100,000m3/d)andtreatmentmethods(conventionalmethod;pretreatment+conventional;pretreatment+conventional+advancedtreatment).•Classificationofwastewatertreatmentplants:scale(<10,000m3/d;1~100,000m3/d;>100,000m3/d)andprocess(AAO;AO;oxidationditch;SBR;commonaerationtank).3.3.4WaterdepartmentsTheaccountingworktakenbywaterdepartmentsisdifferentfromthatofwatercompaniesandwatersectorassociations.Intermsofaccountingprocedures,itcanbedividedintotwosteps.Thefirststepistoestablishthewaterflowandbalanceamongdifferentsystemswithintheorganizationalboundaries.Thesecondstepistoconductcarbonemissionaccountingbasedonthewaterflowandbalanceandtheemissionfactorsprovidedbywatersectorassociations.Ifthecarbonemissionaccountingresultsofallwatercompanieswithintheboundariesareavailable,thetotalcarbonemissioniscalculatedbasedonEquation(3.5).Inaddition,anothertotalcarbonemissioncanbeobtainedwithwaterbalancebasedonEquation(3.6)whichcanbeusedtochecktheintegrityofcarbonaccountingbythewatercompanies.Forsomeplanningareas,ifitisdifficulttoobtaintheaccountingresultsfromwatercompaniesdirectly,thetotalcarbonemissioncanonlybecalculatedaccordingtoEquation(3.6).21Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝑛(3.5)𝐶𝐸=∑𝐶𝐸𝑖𝑖=1Where:Totalcarbonemissionsofthecity,kgCO2-eq𝐶𝐸—Thefirst𝑖enterpriseorgroup,kgCO2-eq𝐶𝐸𝑖—𝑛(3.6)𝐶𝐸=∑𝐶𝐸𝑆𝑖×𝑄𝑖𝑖=1Where:Totalannualcarbonemissionsofthecity,kgCO2-eqThefirst𝑖watersystem,kgCO2-eq/m3𝐶𝐸—Thefirst𝑖wateraffairssystem,m3,watersupplyandsewagetreatmentplants𝐶𝐸𝑆𝑖—aremeasuredbythewaterqualitytothestandard,thewatertransmissionanddistributionnetworkandsewagepipelinesaremeasuredbythetotaltransfer𝑄𝑖—watervolume,andtherainwatersystemismeasuredbythetransferandmanagementwatervolume22Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter4Planningandconstruction4.1OVERVIEWThemainemissionactivitiesintheplanningandconstructionstageofwatersectorsinclude:i)directcarbonemissiongeneratedbyburningfossilfuels;ii)indirectcarbonemissionfromthegenerationofimportedelectricity;iii)indirectcarbonemissionfromtheproductionoftheconstructionmaterialsconsumed;iv)indirectcarbonemissionfromthetransportationofvariousgoods.Astheactivitiesinplanningandconstructionfordifferentsystemsareconsistent,theaccountingequationsprovidedinthischapterareapplicabletoanysystemsofurbanwatersectors.Accordingtothecompletenessandaccessibilityofthematerialandenergyinventoryoftheplanningandconstruction,twoaccountingmethodsareprovidedforemissionactivitiesinthischapter:i)iftheinventorycanbeobtained,theactivitydataandcorrespondingemissionfactors(EFs)areusedforaccounting(Sections4.2to4.4),whichhasarelativelyhighaccuracyandshouldbegivenpriority;ii)ifitisdifficulttoobtaintheinventory,thetotalcarbonemissioncanberoughlyestimatedaccordingtotheprocessingcapacityorinvestmentofthefacilitiesbyleveragingtheprefabricatedcalculationdiagramand/orthequickreferencetables(Section4.5).4.2DIRECTEMISSIONSOFFOSSILFUELThedirectemissionoffossilfuelmainlyreferstocarbonemissionscausedbytheon-siteconsumptionoffossilfuels(coal,oil,naturalgasandtheirderivativefuels)forconstructionmachinery.Accordingtotheavailableconstructioninventory,carbonemissionoffossilfuelconsumptioncanbecalculatedusingthefollowingtwomethods:i)ifthetypesoffossilfuelsandthecorrespondingconsumptioncanbeobtained,Method1isrecommendedforcalculatingthecarbonemissions(Equation(4.1)),andtheaccuracyoftheresultsisrelativelyhigh;ii)ifthedetailsoffossilfuelconsumptionarenotavailable,itcanbecalculatedaccordingtothenumberofmachineshifts(Method2,Equation(4.2)),thoughtheaccuracyoftheresultisquitelow.Method1:(4.1)𝑛𝐶𝐸𝑟𝑙=∑(𝑀𝑟𝑙,𝑖×𝐸𝐹𝑟𝑙,𝑖)𝑖=1Where:Carbonemissionsoffossilfuel,kgCO2-eq𝐶𝐸𝑟𝑙—Totalamountofthefossilfuel𝑖consumed,kgorm3𝑀𝑟𝑙,𝑖—TheEFsoffossilfuel𝑖,kgCO2-eq/kgorkgCO2-eq/m3.SeeAppendixB.1𝐸𝐹𝑟𝑙,𝑖—Totalnumberoffossilfuelsused𝑛—23Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorMethod2:𝑛(4.2)𝐶𝐸𝑟𝑙=∑(𝑇𝑖×𝑆𝑖×𝐸𝐹𝑟𝑙,𝑖)𝑖=1Where:Carbonemissionsoffossilfuel,kgCO2-eq𝐶𝐸𝑟𝑙—𝑇𝑖—Thenumberofshiftsofmachine𝑖𝑆𝑖—Thefossilfuelconsumptionpershiftofmachine𝑖.SeeBuildingCarbonEmission𝐸𝐹𝑟𝑙,𝑖—CalculationStandard(GB/T51366-2019)𝑛—TheEFsoffossilfuelformachine𝑖,kgCO2-eq/kgorkgCO2-eq/m3.SeeAppendixB.1Thenumberofmachinetypesused4.3INDIRECTEMISSIONSFROMELECTRICITYCONSUMPTIONTheelectricityconsumptionintheconstructionperiodalsocontributedasignificantportionofthetotalgreenhousegas(GHG)emissionwhichiscalculatedasshowninEquation(4.3).𝐶𝐸𝑑=𝐸𝑑×𝐸𝐹𝑑(4.3)Where:𝐶𝐸𝑑—Carbonemissionofelectricityconsumption,kgCO2-eq𝐸𝑑—Totalconsumptionofelectricity,kWhTheEFsspecificfortheimportedelectricity,kgCO2-eq/kWh.SeeAppendixB.2𝐸𝐹𝑑—4.4INDIRECTEMISSIONSFROMMATERIALCONSUMPTIONTheindirectemissionfromtheproductionprocessesofvariousmaterialsusedintheplanningandconstructionstagecanbecalculatedasshowninEquation(4.4).𝑛(4.4)𝐶𝐸𝑐𝑙=∑(𝑀𝑐𝑙,𝑖×𝐸𝐹𝑐𝑙,𝑖)𝑖=1Where:Carbonemissionintheproductionprocessofconsumedmaterials,kgCO2-eq𝐶𝐸𝑐𝑙—Theamountofmaterialusedbytype𝑖,torm3𝑀𝑐𝑙,𝑖—TheEFsofmaterial𝑖,kgCO2-eq/m3orkgCO2-eq/t.SeeAppendixB.3𝐸𝐹𝑐𝑙,𝑖—Totalnumberofconstructionmaterialsused𝑛—4.5INDIRECTEMISSIONSFROMTRANSPORTATIONTheconstructionmaterialsand/orservicesconsumedduringtheplanningandconstructionstagerequiretransportationwhichwillgenerateacertainamountofGHGemissions.TheaccountingcanrefertoEquation(4.5).24Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPlanningandconstruction𝑛,𝑙(4.5)𝐶𝐸𝑦𝑠=∑(𝑀𝑦𝑠,𝑖,𝑗×𝐿𝑦𝑠,𝑖,𝑗×𝐸𝐹𝑦𝑠,𝑗)𝑖=1,𝑗=1Where:Carbonemissionofmaterialtransportation,kgCO2-eq𝐶𝐸𝑦𝑠—Thetotalamountofmaterialstransportedbythetransportationtype𝑗inthe𝑀𝑦𝑠,𝑖,𝑗—procurement𝑖,tThedistanceofmaterialstransportedbythetransportation𝑗intheprocurement𝑖,𝐿𝑦𝑠,𝑖,𝑗—kmTheEFsoftransportation𝑗,kgCO2-eq/(t·km).SeeAppendixB.4𝐸𝐹𝑦𝑠,𝑗—Thenumberofprocurementactivities𝑛—Thenumberoftransportationsinoneprocurementactivity𝑙—4.6OVERALLESTIMATIONASAWHOLE4.6.1EstimationbasedonwatervolumehandledInsomecases,thedetailedinventoryaboutmaterialsand/orenergyconsumptionisnotavailableandtheabovemethodsarenolongerapplicable.Alternatively,theGHGemissionoftheconstructionofaspecificfacilitycouldbequantifiedbyregardingthefacility’semissionasawhole.Thereinto,theemissionactivitiesaretheamountsofwaterthefacilityhandles,i.e.,treatmentcapacityforwatertreatmentplants,wastewatertreatmentplants,andwastewaterreclamationplants;watervolumeconveyedbypipenetworks.Then,thecorrespondingemissionintensitieswereformulatedbysummarizingandanalyzingdozensofcasestudiesasshowninTable4.1~4.4(SeeAppendixC.1-C.5fordetails).Overall,themethodsfordifferentfacilitiesrefertoEquation(4.6~4.9)aslistedbelow.𝐶𝐸𝑗𝑠=𝐶𝐸𝑆×𝑄(4.6)Where:𝐶𝐸𝑗𝑠—Carbonemissionofawatertreatmentplantorawastewatertreatmentplant,tCO2-eq𝐶𝐸𝑆—Emissionintensities,tCO2-eq/(10,000m3/d).SeeTable4.2andTable4.4𝑄—Treatmentcapacity,m3/d𝐶𝐸𝑗𝑠=𝐶𝐸𝑆×𝐿(4.7)Where:𝐶𝐸𝑗𝑠—Carbonemissionofpipenetworks,tCO2-eq𝐶𝐸𝑆—Emissionintensities,tCO2-eq/km.SeeTable4-1andTable4-3𝐿—Pipelengthwithdifferentdiameters,km𝑛,𝑙CEgh=∑(CESi×Si+CESj×L)(4.8)𝑖=1,𝑗=1Where:Carbonemissionsofstormwatermanagementsystem,104tCO2-eqCEgh—Emissionintensitiesoffacility𝑖,kgCO2-eq/m2.SeeAppendixC.5CESi—25Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝑆i—Thefootprintofgreenfacility𝑖,m2CESj—Emissionintensityofstormwatersewer𝑗,kgCO2-eq/m2Thelengthofthestormwatersewer,m.IfthelengthofstormwatersewerisnotL—available,Equation(4.9)canbeappliedThenumberoffacilitiestypesusedn—Thenumberofrainwaterpipestypesusedl—L=S×D×103(4.9)Where:S—Areaoforganizationalboundary,km2D—Densityofstormwatersewer,km/km2Table4.1SummaryofEFsofpipesbymaterialsanddiametersforwaterdistributionnetwork.DiameterEmissionfactor(tCO2-eq/km)1DuctileironpipesSteelpipeDN300105.1181.3DN400155.4228.6DN500214.0287.2DN600280.7345.4DN700356.1403.4DN800440.9461.9DN900532.3519.9DN1000630.5578.1DN1200856.0694.41.Thedepthofcoveris0.7m.Table4.2SummaryofEFsofwatertreatmentplantsbydifferentprocessesandtreatmentcapacity.Emissionfactor(tCO2-eq/10,000m3)Processes<50,000m3/d50,000m3/d-100,000m3/≥100,000m3/ddConventionaltreatment1,209.51,070.8833.1Pretreatment+1,445.91,300.71,011.1conventionaltreatmentPretreatment+conventionaltreatment+1,942.81,785.51,437.5advancedteatmentWaterdistributionpump389.6339.4266.8station26Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPlanningandconstructionTable4.3Summaryofcarbonemissionfactorsofwastewatercollectionspipesbymaterialsanddiametersfordrainagepipelines.ReinforcedconcretepipesHDPEpipesDiameterEFs1DiameterEFs1(tCO2-eq/km)(tCO2-eq/km)dn60052.4DN60017.9dn80086.7DN80020.8dn1000126.7DN100024.4dn1200178.8DN120029.9dn1400263.5DN140036.1dn1600346.4DN160044.1dn1800414.9DN180049.6dn2000536.5DN200055.11.Thedepthofcoveris0.7m.Table4.4Summaryofcarbonemissionfactorsofwastewatertreatmentplantsbydifferentprocessesandtreatmentcapacity.Emissionfactor(tCO2-eq/10,000m3)Processes<10,00010,000m3/d-100,000≥100,000m3/dm3/dm3/dWastewatertreatmentplantmeetingDischargeStandard3,275.02,239.91,575.3ClassI-B(excludingsludgedigestion)WastewatertreatmentplantmeetingDischargeStandard4,226.42,543.82,022.9ClassI-B(includingsludgedigestion)WastewatertreatmentplantmeetingDischargeStandard4,748.92,919.82,293.1ClassI-A(nosludgedigestion)WastewatertreatmentplantmeetingDischargeStandard5,657.72,5032,750.8ClassI-A(includingsludgedigestion)UpgradingandtransformingtoawastewatertreatmentplantmeetingDischarge1,602.31,037.6794.1StandardClassI-A(excludingsludgedigestion)27Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorUpgradingandtransformingtoawastewatertreatmentplantmeetingDischarge2421.21,369.51,054.7StandardClassquasi-IV(excludingsludgedigestion)1.TheinfluentCODisassumedtobe350mg/L(BOD=170mg/L).Carbonemissionscanalsobedirectlydeterminedthroughthecarbonemissioncalculationdiagramofplanningandconstruction(Figure4.1~Figure4.4)whicharevisualizedfromTable4.1~4.4.Figure4.1Carbonemissioncalculationdiagramofwaterdistributionnetworkconstructionwithdifferentmaterials(a.Ductileironpipes;b.Steelpipes)(withasoilcoverdepthof0.7m).28Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPlanningandconstructionFigure4.2Carbonemissioncalculationdiagramforconstructionofwatertreatmentplantsandpumpingstations.29Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure4.3Carbonemissioncalculationdiagramofsewagepipeconstructionwithdifferentmaterials(a.Reinforcedconcretepipes;b.HDPEpipes)(withasoilcoverdepthof0.7m).30Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPlanningandconstructionFigure4.4Calculationdiagramofcarbonemissioninconstructionofwastewatertreatmentplantwithdifferenteffluentdischargestandards.4.6.2EstimationbasedoninvestmentInviewofthecapitalcostembodiedinthematerialsusedinconstruction,carbonemissionscanalsoberoughlycalculatedaccordingtoinvestmentasshowninEquation(4.10):𝐶𝐸𝑗𝑠=𝐶𝐸𝑆𝑡𝑧×𝑇𝑍(4.10)Where:𝐶𝐸𝑗𝑠—Carbonemissionsofplanningandconstruction,104tCO2-eq𝐶𝐸𝑆𝑡𝑧—Carbonemissionintensity,104tCO2-eq/104CNY.SeeTable4.5~4.9𝑇𝑍—Thetotalinvestment,104CNYTable4.5Summaryofinvestmentcarbonemissionfactorsofwaterdistributionpipesbydifferentmaterialsanddiameters.DiameterEmissionfactor(tCO2-eq/104CNY)DuctileIronPipesSteelpipeDN3001.331.88DN4001.541.99DN5001.601.90DN6002.122.40DN7002.422.68DN8002.912.98DN9003.132.91DN10003.402.98DN12004.053.1631Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable4.6Summaryofinvestmentcarbonemissionfactorsofwatertreatmentplantsbydifferenttreatmentprocessesandcapacities.Emissionfactor(tCO2-eq/104CNY)Processes<50,000m3/d50,000m3/d-100,000≥100,000m3/dm3/dConventionaltreatment1.031.021.00Pretreatment+1.031.041.01conventionaltreatmentPretreatment+conventionaltreatment+1.001.011.00advancedtreatmentWaterdistributionpump1.000.980.99stationTable4.7Summaryofinvestmentcarbonemissionfactorsofwatertreatmentplantsbydifferenttreatmentprocessesandcapacities.ReinforcedconcretepipesHDPEpipeDiameterEFsDiameterEFs(tCO2-eq/104CNY)(tCO2-eq/104CNY)DN6003.1DN6000.5DN8004.3DN8000.5DN10005.2DN10000.5DN12006.1DN12000.5DN14008.1DN14000.5DN16008.8DN16000.5DN18009.2DN18000.5DN200010.7DN20000.5Table4.8SummaryofinvestmentEFsofwastewatertreatmentplantsbydifferenteffluentstandardsandtreatmentcapacity.EFs(tCO2-eq/104CNY)Processes<10,00010,000m3/d-100,000≥100,000m3/dm3/dm3/dWastewatertreatmentplantmeetingDischargeStandard1.31.31.1ClassI-B(excludingsludgedigestion)WastewatertreatmentplantmeetingDischargeStandard1.31.21.2ClassI-B(includingsludgedigestion)WastewatertreatmentplantmeetingDischargeStandard1.31.21.2ClassI-A(nosludgedigestion)32Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestPlanningandconstructionEFs(tCO2-eq/104CNY)Processes<10,00010,000m3/d-100,000≥100,000m3/dm3/dm3/dWastewatertreatmentplant1.3meetingDischargeStandard0.91.2ClassI-A(includingsludge1.31.21.2digestion)1.3Upgradingandtransformingto11awastewatertreatmentplantmeetingDischargeStandardClassI-A(excludingsludgedigestion)UpgradingandtransformingtoawastewatertreatmentplantmeetingDischargeStandardClassquasi-IV(excludingsludgedigestion)Table4.9SummaryofinvestmentEFsofgreenfacilities.StormwatercontrolfacilitiesTotalemissionintensity(tCO2-eq/104CNY)GrassedswalesTransfertypedrygrassplanting0.422.81ditchPermeabledrygrassditch0.996.59Wetgrassditch1.8312.22PermeableSidewalk1.896.32pavementDrivingload≤5t4.0113.37Drivingload=5-8t5.2017.34Drivingload=8-13t6.0019.99BioretentionBioretentionzone0.191.03facilityRaingarden0.552.92(takingpurificationraingardenasanexample)Simpleecologicaltreepool2.0711.06Purifyingecologicaltreepool1.9510.39Highflowerbeds2.8715.31(takingthestagnanthighflowerbedsasanexample)Lowelevationgreenbelt2.623.27GreenroofSimple2.858.56Gardenstyle6.5819.74Cistern4.386.57Pondwetland0.140.2233Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter5Operationandmaintenance5.1OVERVIEWThemainemissionactivitiesoftheurbanwatersectorinoperationandmaintenancestageinclude:i)directcarbonemissionsfrombiochemicalprocesses,particularlyinwastewatermanagementsystem;ii)directcarbonemissionsgeneratedbyburningfossilfuel;iii)indirectcarbonemissionsfromtheconsumptionofimportedelectricity;iv)indirectcarbonemissionsfromtheproductionofchemicalsand/ormaterialsconsumed;v)indirectcarbonemissionsfromthetransportationofgoods.ItisworthnotingthatsomefacilitiesoftheurbanwatersectorcanfixCO2andachieveGHGremovalsthroughplantssequestration.Besides,energyandresourcerecoveryandimportationalsoproducecarboncredits,afactorwhichisalsoconsidered.TheaccountingmethodsforsomecommonemissionactivitiesamongvarioussystemsaresummarizedinSection5.2,andtheotherexclusiveactivitiesforspecificsystemarepresentedinSections5.3~5.6,respectively.5.2GENERALPROVISIONS5.2.1DirectemissionsoffossilfuelThedirectemissionoffossilfuelsmainlyreferstocarbonemissionscausedbytheon-siteconsumptionoffossilfuels(coal,oil,naturalgasandtheirderivativefuels)bysomemechanicalpiecesofequipment.ThisiscalculatedbyEquation(5.1).n(5.1)CESrl=∑(Mrl,i×EFrl,i)/Qi=1Where:𝐶𝐸𝑆𝑟𝑙—Carbonemissionintensityoffossilfuel,kgCO2-eq/m3𝑀𝑟𝑙,𝑖—Totalamountoffossilfuel𝑖consumedintheinventoryyear,kg/aorm3/a𝐸𝐹𝑟𝑙,𝑖—Theemissionfactors(EFs)offossilfuel𝑖,kgCO2-eq/kgorkgCO2-eq/m3.SeeAppendixB.1𝑄—Thevolumeofwaterhandledbythetargetedsystemsand/orfacilitiesintheinventoryyear,m3/a.SeeSection3.3.1𝑛—Totalnumberoffossilfuelused5.2.2IndirectemissionsfromelectricityconsumptionThecalculationofcarbonemissionscausedbyelectricityconsumptionintheoperationandmaintenancestagecanbeimplementedbythefollowingmethods:i)whenelectricityconsumptiondataisavailable,Method1canbeapplied(Equation(5.2));ii)intermsofpumps,iftheelectricityconsumptiondatais35Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectornotavailable,Method2isrecommendedbyleveragingthepumpworkingparametersandliftingheightinformation(Equation(5.3)).Method1:𝐶𝐸𝑆𝑑=(𝐸𝑑×𝐸𝐹𝑑)/𝑄（5.2）Where:𝐶𝐸𝑆𝑑—Carbonemissionintensityofelectricityconsumption,kgCO2-eq/m3𝐸𝑑—Thetotalimportedelectricityconsumptionintheinventoryyear,kWh/a𝐸𝐹𝑑—TheEFsspecificfortheimportedelectricity,kgCO2-eq/kWh.SeeAppendixB𝑄—Thevolumeofwaterhandledbythetargetedsystemsand/orfacilitiesintheinventoryyear,m3/a.SeeSection3.3.1Method2:𝑛𝑔×𝑙×𝜌×𝐸𝐹𝑑（5.3）𝐶𝐸𝑆𝑑=∑𝑖=1(3.6×106×𝜂𝑖)Where:𝐶𝐸𝑆𝑑—Carbonemissionintensityofelectricityconsumption,kgCO2-eq/m3𝑔—Gravityacceleration,9.8m/s2𝑙—Elevationheight,mρ—Densityofwater,kg/m3.Defaultis1000kg/m3𝐸𝐹𝑑—TheEFsspecificfortheimportedelectricity,kgCO2-eq/kWh.SeeAppendixB.2𝜂𝑖—Theworkingefficiencyofthepumpbytype𝑖𝑛—Totalnumberofpumptypesused5.2.3IndirectemissionsofmaterialconsumptionIndirectemissionfromtheproductionprocessesofvariouschemicalsormaterialsusedintheoperationandmaintenancestagecanbecalculatedasshowninEquation(5.4).𝑛(5.4)𝐶𝐸𝑆𝑐𝑙=∑(𝑀𝑐𝑙,𝑖×𝐸𝐹𝑐𝑙,𝑖)/𝑄𝑖=1Where:𝐶𝐸𝑆𝑐𝑙—Carbonemissionintensityofchemicalsand/ormaterialsconsumption,kgCO2-eq/m3𝑀𝑐𝑙,𝑖—Theamountofmaterialusedbytype𝑖intheinventoryyear,kg/a𝐸𝐹𝑐𝑙,𝑖—TheEFsofmaterialsorchemicalsconsumedbytype𝑖,kgCO2-eq/kg.SeeAppendixB.5𝑛—Totalnumberofconstructionmaterialtypesused𝑄—Thevolumeofwaterhandledbythetargetedsystemsand/orfacilitiesintheinventoryyear,m3/a.SeeSection3.3.15.2.4IndirectemissionsoftransportationTheconstructionmaterialsand/orchemicalsconsumedduringtheplanningandconstructionstagerequiretransportationswhichwillgenerateacertainamountofGHGemissions.Theaccountingcanrefer36Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenancetoEquation(5.5).𝑛,𝑙(5.5)𝐶𝐸𝑆𝑦𝑠=∑(𝑀𝑦𝑠,𝑖,𝑗×𝐿𝑦𝑠,𝑖,𝑗×𝐸𝐹𝑦𝑠,𝑗)/𝑄𝑖=1,𝑗=1Where:𝐶𝐸𝑆𝑦𝑠—Carbonemissionintensityofmaterialorchemicaltransportation,kgCO2-eq/m3𝑀𝑦𝑠,𝑖,𝑗—Thetotalamountofmaterialstransportedbythetransportationoftype𝑗intheithprocurementintheinventoryyear,t/a𝐿𝑦𝑠,𝑖,𝑗—Thedistanceofmaterialsorchemicalstransportedbythetransportationof𝑗intheithprocurementintheinventoryyear,km𝐸𝐹𝑦𝑠,𝑗—TheEFsoftransportationof𝑗,kgCO2-eq/(t·km).SeeAppendixB.4𝑛—Thenumberofprocurementactivities𝑙—Thenumberoftransportationtypesintheithprocurementactivity𝑄—Thevolumeofwaterhandledbythetargetedsystemsand/orfacilitiesintheinventoryyear,m3/a.SeeSection3.3.15.3WATERSUPPLYSYSTEMS5.3.1AccountingboundaryAwatersupplysystemiscomposedofwaterabstractionfacilities,watertreatmentplants,andwaterdistributionnetworks.Thesemodulesworktogethertoserveresidentswithqualifiedandsafewaterinasequentandsynergicway.Accordingtothetypeofwatersources,watertreatmentfacilitiescanbedividedintoconventionalwatertreatmentplantsusingsurfacewaterandgroundwaterassources,aswellasdesalinationplantsthatmakeuseofseawater.Inaddition,long-distancewatertransfercanalleviatetheshortageofwatersupplyforsomecities,andsohasalsobeenincludedaspartofthewatersupplysysteminthisGuidelines.AsshowninFigure5.1,theorganizationalboundaryofthewatersupplysystemcoversallfacilitiesfromwatersourcetousers,includinglong-distancewatertransferpipelinesandpumpingstations,waterabstractionpipelinesandpumpingstations,watertreatmentplants,andwaterdistributionpumpsandnetworks.ThespecificcarbonemissionactivitiesandemissioncategoriesaresummarizedinTable5.1.37Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure5.1Schematicdiagramoftheorganizationalboundaryofwatersupplysystems.38Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenanceTable5.1Summaryofcarbonemissionactivitiesofwatersupplysystems.Scope(GHGCategory(ISO14064-1:WaterabstractionConventionalwaterDesalinationplantLong-distanceprotocol)2018)facilitiesandtreatmentplantwatertransferdistributionnetworkDirectGHGemissionsproducedatfacilitiesDirectGHGemissionsandFossilfuelconsumptionand/orassetsownedbyremovalswatersectorsIndirectGHGemissionsElectricityElectricityincurredbyanenergyIndirectGHGemissionsElectricityconsumptionbyElectricityconsumptiondueconsumptionbyconsumptionforproviderwhenproducingfromimportedenergywaterabstractionand/ortobackwashing,mechanicalvacuumpumpsandpumpsenergypurchasedbydistributionpumpsmixer,etc.filterpresseswatersectorsIndirectGHGemissionsTransportationformaterials,chemicalsinput,by-productsoutput,etc.fromtransportationIndirectGHGemissionsMaterialandchemicalMaterialandchemicalMaterialandchemicalsMaterialfromproductsusedbyconsumptionconsumptionconsumptionconsumptionOtherindirectGHGorganizationemissionsnotIndirectGHGemissionsattributabletoenergyassociatedwiththeuseof-Disposalofsludge--productsfromtheorganizationsIndirectGHGemissions—---fromothersources39Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector5.3.2WaterabstractionfacilitiesWaterabstractionfacilitiesarecomprisedofpipesandpumpswhichworktogethertocollectrawwaterfromasource,e.g.,groundwaterorsurfacewater,andconveyittoadistributionnetworkoratreatmentplant.ThemainGHGemissioncomesfromelectricityconsumptionbypumpsofwhichtheaccountingmethodisshowninEquation(5.2)andEquation(5.3).Whenelectricityconsumptiondataaredifficulttoobtain,thefollowingmethodscanbereferredto,buttheaccuracyoftheresultsispoor.ThecalculationisasshowninEquation(5.6).𝐶𝐸𝑆𝑑=𝐸𝐼×𝐸𝐹𝑑(5.6)Where:𝐶𝐸𝑆𝑑—Carbonemissionintensityofelectricityconsumption,kgCO2-eq/m3𝐸𝐼—Electricityintensityofabstractinggroundwaterorsurfacewaterinspecificarea,kWh/m3.SeeTable5.2𝐸𝐹𝑑—TheEFsspecificfortheimportedelectricity,kgCO2-eq/kWh.SeeAppendixB.2Table5.2Electricityintensityofwaterabstractionbyregion(Xiang,2019).SurfacewaterGroundwaterElectricityintensityProvinceElectricityintensityProvinceElectricityintensitykWh/m3kWh/m3kWh/m30.2(nationalHebei0.53Jiangsu0.36average)Henan0.30Zhejiang0.43Shaanxi0.64Anhui0.32Shanxi0.62Fujian0.40InnerJiangxi0.370.30MongoliaLiaoning0.21Guangdong0.41Ningxia0.27Guangxi0.34Gansu0.50Hainan0.41Hubei0.22Chongqing0.57Hunan0.40Sichuan0.30Shandong0.47Guizhou0.36Beijing0.44Yunnan0.45Tianjin0.66Tibet0.29Jilin0.35Qinghai0.52Heilongjiang0.43Xinjiang0.60Shanghai0.395.3.3Watertreatmentplants5.3.3.1IndirectemissionofelectricityconsumptionForcarbonemissionfromimportedelectricityconsumptionforoperationandmaintenanceofwatertreatmentplants,refertoEquation(5.2).40Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance5.3.3.2IndirectemissionofmaterialconsumptionTheindirectcarbonemissionofthematerialsconsumptionforoperationandmaintenanceofwatertreatmentplantscanrefertoEquation(5.4).5.3.3.3IndirectemissionsoftransportationTheindirectcarbonemissionfromthetransportationofchemicalimportorsludgeexportinthewatertreatmentplantcanrefertoEquation(5.5).5.3.3.4WatertreatmentsludgedisposalAllwatertreatmentplantsproducewaste/residueknownaswatertreatmentsludge(WTS)fromthesedimentationprocessand/orbackwashingoffiltration.WTSismainlycomposedofinorganicparticlessuchasfinesandandsediment,alongwithverysmallamountsoforganiccomponents.Afterconditioninganddewatering,WTSistransportedoutsideplantsanddisposedofinlandfilling.GiventheminoramountsoforganiccontentinWTS,theGHGemissionduetotheorganicdegradationisusuallynotconsidered.IftheorganiccontentinWTSisrelativelylarge,CH4canbeproducedbytheanaerobicfermentationoforganicmatterwhichcanbecalculatedbyEquation(5.7).𝐶𝐸𝑆𝐶𝐻4−𝑠𝑙=𝑀𝑠𝑠×𝐷𝑂𝐶×𝐷𝑂𝐶𝑓×𝑀𝐶𝐹×𝐹×(1−𝑂𝑋)×16/12/𝑄×28(5.7)Where:𝐶𝐸𝑆𝐶𝐻4−𝑠𝑙—CH4emissionintensityofWTSlandfilling,kgCO2-eq/m3𝑀𝑠𝑠—TotaldrysolidofWTSintheinventoryyear,kgTS/a𝐷𝑂𝐶—Degradableorganiccarboncontent,kgC/kgTS𝐷𝑂𝐶𝑓—FractionofDOCdecomposed,%.Defaultis50%𝑀𝐶𝐹—CH4correctionfactor.Defaultis1.0𝐹—ProportionofCH4inreleasedgas,%.Defaultis50%𝑂𝑋—TheratioofCH4beingoxidizedbeforeescapingintoatmosphere.Defaultis0.1(whenwellmanagedandcoveredwithbreathablematerial))or0(whennothandledproperly)(IPCC,2019)16/12—MolecularmassratioofCH4andC𝑄—Thetotalamountofwatertreatedintreatmentplantintheinventoryyear,m3/a28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH45.3.4Desalinationplants5.3.4.1DirectcarbonemissionsoffossilfuelsThedirectemissionsoffossilfuelmainlyrefertocarbonemissioncausedbytheon-siteconsumptionoffossilfuels(coal,oil,naturalgasandtheirderivativefuels)tosupport,forexample,thedistillationprocess.CarbonemissionintensityiscalculatedaccordingtoEquation(5.8).𝑛(5.8)𝐶𝐸𝑆𝑟𝑙=∑(𝐴×𝐸𝐹𝑟𝑙,𝑖×𝑅𝑖)𝑖=1Where:𝐶𝐸𝑆𝑟𝑙—Carbonemissionintensityoffossilfuelconsumption,kgCO2-eq/m341Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝐴—Thermalenergyintensityofdesalinationunit,GJ/m3,providedbytheequipmentmanufacturer𝐸𝐹𝑟𝑙,𝑖—TheEFsoffossilfuelbytype𝑖,kgCO2-eq/GJ.SeeAppendixB.1𝑅𝑖—Theproportionoffuelbytype𝑖used𝑛—totalnumberoffossilfuelused5.3.4.2IndirectcarbonemissionofelectricityconsumptionThecarbonemissionfromimportedelectricityconsumptionforoperationandmaintenanceofdesalinationplantscanrefertoEquation(5.2).5.3.4.3IndirectcarbonemissionofmaterialconsumptionTheindirectcarbonemissionofthematerialsconsumptionforoperationandmaintenanceofdesalinationplantscanrefertoEquation(5.4).5.3.4.4IndirectcarbonemissionoftransportationTheindirectcarbonemissionfromthetransportationofchemicalorothergoodsimportinthedesalinationplantcanrefertoEquation(5.5).5.3.5WaterdistributionnetworkThecarbonemissionfromimportedelectricityconsumptionforoperationandmaintenanceofwaterdistributionnetworkcanrefertoEquation(5.2)and(5.3).5.3.6Long-distancewatertransferLong-distancewatertransferisthemovingofwaterfromawatershedwithasurplus(donorbasin)toawatershedsufferingfromashortage(recipientbasin).Thewateristransferredprimarilytoalleviatewaterscarcityintherecipientbasinandtravelslongdistancesviacomplexpipelineandcanalsystems.Theindirectcarbonemissionsfromimportedelectricityconsumption(mainlybypumps)canbecalculatedaccordingtoEquation(5.2)and(5.3).Whentheelectricityconsumptiondataarenotavailable,thefollowingmethodscanbereferredto,ontheonehand,thewaterliftingheightandtransferdistancecanbeusedtoestimatecarbonemissionintensity(Method1,Equation(5.9)).Ontheotherhand,aquickcalculationdiagram(Figure5.2)ispreparedfordirectlyreadingemissionintensitybasedonwaterliftingheightandtransferdistance(Method2).Itshouldbenotedthattheentirewatertransferlinecanbedividedintoseveralsectionsbasedonslopewhichthenarecalculatedseparately,andfinallysummedup.Method1:𝑛𝑔×ℎ𝑖×𝜌𝐶𝐸𝑆𝑑=∑𝑖(𝐸𝐼×𝑙𝑖+3.6×106×𝜂𝑖)×𝐸𝐹𝑑(5.9)Where:𝐶𝐸𝑆𝑑—Carbonemissionintensityoflong-distancewatertransfer,kgCO2-eq/m3𝐸𝐼—Energyintensityoflong-distancewatertransfer,kWh/(m3·km).Defaultis9.73×10-6kWh/(m3km)(Xiang,2019)𝐸𝐹𝑑—TheEFsspecificfortheimportedelectricity,kgCO2-eq/kWh.SeeAppendixB-2𝑙𝑖—Thelengthofsection𝑖bydividingtheentiretransferlineintonsections,km42Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance𝑔—Gravityacceleration,9.8m/s2ℎ𝑖—Theliftingheightofthesection𝑖,mρ—Thedensityofwater,kg/m3.Defaultis1,000kg/m3𝜂𝑖—Theworkingefficiencyofthepumpunitinthesection𝑖.Defaultis75%-80%Method2:Figure5.2Quickcalculationdiagramofcarbonemissionintensityoflong-distancewatertransfer.5.4WASTEWATERMANAGEMENTSYSTEMS5.4.1AccountingboundaryWastewatermanagementsystemreferstoallthefacilitiesforwastewatercollection,conveyance,treatment,discharge,andassociatedby-productdisposal.Accordingtospecificfunctionsandworkingsequence,wastewatermanagementsystemcanbedividedfurtherintothreemodules:wastewatercollectionnetwork,wastewatertreatmentplants,andsludgetreatmentanddisposalfacilities.Thecarbonemissionactivitiesofwastewatermanagementsystemsarecomplicated,withtheirownexclusivefeaturesbecauseofthehighconcentrationoforganicmatter/kjeldahlnitrogenloadedinwastewater.Facilitieswithorganicmatter/nitrogenflowingthroughthemareallpotentialsitesofGHGemissionsandshouldbeincludedintheaccountingboundary.AsdepictedinFigure5.3,theorganizationalboundaryofthewastewatermanagementsystemcoversalltreatmentunitsfromthebeginningpointsofthecommunityseptictankorwastewaterbeingdischargedintothecollectionnetworktothepointofthetreatedwastewaterbeingdischargedintothereceivingwaterbody.TheaccountingboundaryandemissionactivitiesaresummarizedinTable5.3indetail.43Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure5.3Schematicdiagramoftheorganizationalboundaryofthewastewatermanagementsystem.44Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenanceTable5.3Summaryofthecarbonemissionactivitiesofthewastewatermanagementsystem.Scope(GHGCategory(ISO14064-1:WastewatercollectionWastewatertreatmentplantSludgetreatmentandProtocol)2018)networkdisposalDirectGHGDirectGHGemissionsandEmissionsfrombiochemicalEmissionsfrombiochemicalEmissionsfrombiochemicalemissionsproducedremovalsprocessesinseptictanksandprocessesinwastewatertreatmentprocessesinsludgetreatmentunitatfacilitiesand/orassetsownedbythedrainagepipesunitFossilfuelconsumptionwatersectorsCarbonremovalsbyresourceandenergyrecovery(electricity,heat,phosphorus,etc.)IndirectGHGemissionsincurredbyIndirectGHGemissionsfromElectricityconsumptionbysepticElectricityconsumptionbyElectricityconsumptionbyanenergyproviderimportedenergytankcleaning,pumpingstations,mechanicalequipment,suchaspumps,heating,mixers,etc.whenproducingthewaterpumps,mixers,andaeratorsenergypurchasedbyetc.thewatersectorsIndirectGHGemissionsfromTransportationforvariousmaterials,chemicalsinput,andsludgeoutput,etc.transportationOtherindirectGHGIndirectGHGemissionsfromMaterialand/orchemicalconsumption,suchasphosphorusremovalagents,coagulants,disinfectants,etc.productsusedbyorganizationemissionsnotIndirectGHGemissionsEmissionsfrombiochemicalEmissionsfrombiochemicalprocessesduetosludgedisposalattributabletoenergyassociatedwiththeuseofprocessesduetocombinedsewer—productsfromtheorganizationsoverflow(CSO)IndirectGHGemissionsfrom———othersources45Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector5.4.2Wastewatercollectionnetworks5.4.2.1FossilCO2emissionsTheorganicmatterinwastewaterispartlyattributedtotheusageofchemicalproducts,e.g.,detergents,PPCPs,whichhaveingredientssourcedfromfossilfuels.Assuch,theproducedCO2fromthedegradationofthispartoforganicmattershouldbeclassifiedasabiogenicandincludedintheaccountingboundary.5.4.2.1.1Septictanks/drainagesystemsThequantificationoffossilCO2fromseptictanks/drainagesystemsisbasedontheproportionoffossilorganicmatterinthetotalorganicmatterinwastewateraswellastotalCO2produced.ThequantificationcanbecalculatedasEquation(5.10)and(5.11)(Topark,1995).1(5.10)𝐶𝐸𝑆𝐶𝑂2−ℎ𝑔=𝐹𝐶𝐹×𝐸𝐹𝐶𝑂2×𝐶𝑂𝐷×(1−1+𝜂𝑇×𝑡)(5.11)𝜂𝑇=𝜂20∙𝜀𝑇−20Where:𝐶𝐸𝑆𝐶𝑂2−ℎ𝑔—EmissionintensityoffossilCO2fromseptictanks/drainagesystem,kgCO2-eq/m3𝐹𝐶𝐹—Proportionoffossilorganicmatterintotalorganicmatterinwastewater,%.5%~20%ingeneraland10%recommendedprovidednodata𝐸𝐹𝐶𝑂2—MaximumCO2producingcapacityunderanaerobiccondition,kgCO2/kgCOD.Defaultis1.47(IPCC,2006)𝐶𝑂𝐷—Totalorganicallydegradablematteronaverageinwastewaterflowingtoseptictanks/drainagesystem,kgCOD/m3𝜂𝑇—Degradationfractionoforganicmatterinseptictanks/drainagesystem,SeeEquation(5.11)𝑡—Hydraulicretentiontimeofseptictanks/drainagesystem,d𝜂20—Degradationfractionoforganicmatterat20°C.Defaultis0.221𝜀—Correctionfactor.Defaultis1.117𝑇—Theannualaveragetemperatureofthewastewaterinseptictanks/drainagesystem,℃5.4.2.2CH4emissionsInthewastewatercollectionsystem,duetotheexistenceofananaerobicenvironment,CH4maybeproducedfromtheanaerobicdegradationoforganicmatterinwastewater.5.4.2.2.1SeptictanksSeptictanksgenerallyoperateinanaerobicenvironments,underwhichconditionsorganicmatterisconvertedintoCH4.Twoaccountingmethodsareprovidedasfollows:1)whentheinfluentCODconcentrationoftheseptictankisavailable,itisrecommendedtoapplytheemissionfactormethod(IPCC,2019)(Method1);or2)thepopulationequivalentmethod,whichcanbeusedtoestimateCH4emission(Method2)(Leverenz,2011).Method1ismoreaccuratethanMethod2.TheequationsfortwomethodsarelistedasEquation(5.12-5.13).46Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenanceMethod1:𝑛1𝐶𝐸𝑆ℎ𝑓𝑐=∑𝑖=1[𝐶𝑂𝐷𝑖×(1−1+𝜂𝑇,𝑖𝑡𝑖)×𝑄ℎ𝑓𝑐,𝑖]×𝐸𝐹𝐶𝐻4/𝑄𝑦×28(5.12)Where:𝐶𝐸𝑆ℎ𝑓𝑐—EmissionintensityofCH4fromseptictanks,kgCO2-eq/m3𝐶𝑂𝐷𝑖—Organicallydegradablematteronaverageinwastewaterflowingtoseptictanki,kgCOD/m3𝜂𝑇,𝑖—Degradationfractionoforganicmatterinseptictanki.SeeEquation(5.11)𝑡𝑖—Hydraulicretentiontimeofseptictanki,d𝑄ℎ𝑓𝑐,𝑖—Totalwastewaterinfluentvolumeofseptictankiintheinventoryyear,m3/a𝐸𝐹𝐶𝐻4—Emissionfactor,kgCH4/kgCOD.Defaultis0.25(IPCC,2019)𝑄𝑦—Totalwastewaterconveyancevolumeofthedrainagesystemintheinventoryyear,m3/a𝑛—Thenumberofseptictanksintheaccountingboundary28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4Method2:𝐸𝐹𝑃𝐸(5.13)𝐶𝐸𝑆ℎ𝑓𝑐=𝑄𝑃𝐸×365Where:𝐶𝐸𝑆ℎ𝑓𝑐—EmissionintensityofCH4fromseptictanks,kgCO2-eq/m3𝐸𝐹𝑃𝐸—CH4emissionpercapitaforatypicalseptictank,kgCO2-eq/(caa).Defaultis8.5(Leverenz,2010)𝑄𝑃𝐸—Wastewaterproductionpercapita,m3/(caa)5.4.2.2.2WastewatersewersTwoaccountingmethodsareprovidedasfollows:1)whenthehydraulicparametersofeachsewersectioncanbeobtained,itisrecommendedtoapplyMethod1(Willis,2018)bycalculatingthecarbonemissionofeachsectionrespectivelyofwhichtheaccountingaccuracyishigh;2)iftheorganicmattercontentofwastewaterisavailable,Method2(Topark,1995),basedonEFs,canalsobeapplied,althoughitsaccuracyislowerthanmethod1.TheequationsforthetwomethodsarelistedasEquation(5.14-5.16).Method1:𝑛𝑄𝑖−0.74𝐶𝐸𝑆𝐶𝐻4=0.419×1.05𝑇−20×∑[(3600×24)0.26×𝐷𝑖0.28×𝑆𝑖−0.138×𝐿𝑖]×28()(5.14)𝑖=1Where:𝐶𝐸𝑆𝐶𝐻4—EmissionintensityofCH4fromsewer,kgCO2-eq/m3𝑇—Temperatureofwastewateronaverageinsewer,℃𝑄𝑖—Wastewaterflowinsewerofsectioni,m3/d𝐷𝑖—Thediameterofsewersectioni,m47Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝑆𝑖—Theslopeofsewersectioni𝐿𝑖—Thelengthofsewersectioni,m28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4𝑛—ThenumberofsegmentssewerisdividedMethod2:1(5.15)𝐶𝐸𝑆𝐶𝐻4=𝐸𝐹𝐶𝐻4×𝐶𝑂𝐷×(1−1+𝜂𝑇∙𝑡)×28(5.16)𝜂𝑇=𝜂20𝜀𝑇−20Where:𝐶𝐸𝑆𝐶𝐻4—EmissionintensityofCH4fromsewer,kgCO2-eq/m3𝐸𝐹𝐶𝐻4—Emissionfactor,kgCH4/kgCOD.Defaultis0.25(IPCC,2006)𝐶𝑂𝐷—Totalorganicallydegradablematteronaverageinwastewaterflowingtosewer,kgCOD/m3𝜂𝑇—Degradationfractionoforganicmatterinsewer.SeeEquation(5.16)𝑡—Hydraulicretentiontimeofseweronaverage,d28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4𝜂20—Degradationfractionoforganicmatterat20°C.Defaultis0.221𝜀—Correctionfactor,1.117𝑇—Theannualaveragetemperatureofthewastewaterinsewer,℃5.4.2.2.3CombinedseweroverflowCombinedSewerOverflow(CSO)isatermusedtodescribewhathappenswhencombinedsewersystemsbecomeoverwhelmedbyexcessstormwaterandoverflowintonearbystreamsandrivers.Sincetheoverflowedwastewaterisuntreated,oronlypartiallytreated,theresidualorganicmatterand/ornitrogenwillinducetheproductionofgreenhousegasesinstreamsandrivers.TheCH4emissionintensityofCSOiscalculatedasEquation(5.17).𝑛(5.17)𝐶𝐸𝑆𝐶𝐻4−𝐶𝑆𝑂=∑(𝑀𝑂,𝑖×Q𝐶𝑆𝑂,𝑖)×𝐸𝐹𝐶𝐻4−𝐶𝑆𝑂×28/𝑄𝑦𝑖=1Where:𝐶𝐸𝑆𝐶𝐻4−𝐶𝑆𝑂—EmissionintensityofCH4fromCSOevents,kgCO2-eq/m3𝑀𝑂,𝑖—Theorganicallydegradablemattercontentofoverflowedwastewateronaverageineventi,kgCOD/m3orkgBOD/m3Q𝐶𝑆𝑂,𝑖—Theoverflowvolumeofwastewaterineventi,m3𝐸𝐹𝐶𝐻4−𝐶𝑆𝑂—EmissionfactorofCH4,kgCH4/kgCODorkgCH4/kgBOD.SeeTable5.428—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4𝑄𝑦—Totalwastewaterconveyancevolumeofthedrainagesystemintheinventoryyear,m3/a𝑛—ThenumberofCSOeventintheinventoryyear48Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenanceTable5.4SummaryofCH4EFsofwastewaterbydischargepathway(IPCC,2019).DischargepathwayCH4EFs2kgCH4/kgBOD5kgCH4/kgCODDischargetoaquaticenvironments10.068(0.0024~0.028(0.001~0.16)0.068)Dischargetoreservoirs,lakes,estuaries0.114(0.048~0.16)0.048(0.02~0.068)Dischargetonon-reservoirs,rivers,estuaries0.021(0.0024~0.009(0.001~0.036)0.015)1.Whenthereisnoinformationaboutdischargepathway,thiscanbereferredto.2.Forvalueprovidedarange,thevaluecanbetakenbasedonthewaterqualityofreceivingbody.Alowervalueisusedforhigh-qualitywater,andviceversa.5.4.2.3N2OemissionsInwastewatercollectionsystem,thebiologicaltransformationofnitrogencompounds,i.e.,nitrificationanddenitrification,canleadtotheproductionofN2O.5.4.2.3.1WastewatersewersTwoaccountingmethodsareprovidedasfollows:1)whenthenitrogencontentofwastewaterflowingintosewerisavailable,itisrecommendedthattheemissionfactormethodbeapplied(Method1)or2)thepopulationequivalentmethodcanbeusedtoestimateN2Oemission(Method2).Method1ismoreaccuratethanMethod2.TheequationsforthetwomethodsarelistedasEquation(5.18)andEquation(5.19).Method1:44(5.18)𝐶𝐸𝑆𝑁2𝑂=𝐸𝐹𝑁2𝑂×（𝑇𝑁𝑜−𝑇𝑁𝑒）×28×265Where:𝐶𝐸𝑆𝑁2𝑂—EmissionintensityofN2Ofromsewer,kgCO2-eq/m3𝐸𝐹𝑁2𝑂—Emissionfactor,kgN2O/kgN.Defaultis0.005(IPCC,2006)𝑇𝑁𝑜—Theaveragenitrogenconcentrationofwastewateratthebeginningofsewer,kgN/m3𝑇𝑁𝑒—Theaveragenitrogenconcentrationofwastewaterattheendofsewer,kgN/m3265—GlobalwarmingpotentialofN2O,265kgCO2-eq/kgN2O4248—TheconversionofkgN2O-NintokgN2OMethod2:𝐸𝐹𝑁2𝑂,𝑃𝐸(5.19)𝐶𝐸𝑆𝑁2𝑂=𝑄𝑃𝐸×365×265Where:𝐶𝐸𝑆𝑁2𝑂—EmissionintensityofN2Ofromsewer,kgCO2-eq/m3𝐸𝐹𝑁2𝑂，𝑃𝐸—N2Oemissionpercapita,kgN2O/(caa).Defaultis1.5~3.5×10-3(Elena,2015)49Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝑄𝑃𝐸—Wastewaterproductionpercapita,m3/(caa)265—GlobalwarmingpotentialofN2O,265kgCO2-eq/kgN2O5.4.2.3.2CSOTheN2OemissionintensityofCSOiscalculatedasEquation(5.20).𝑛44𝐶𝐸𝑆𝑁2𝑂−𝐶𝑆𝑂=∑(TN𝑂,𝑖×Q𝐶𝑆𝑂,𝑖)×𝐸𝐹𝑁2𝑂−𝐶𝑆𝑂×28×265/𝑄𝑦(5.20)𝑖=1Where:EmissionintensityofN2OfromCSOevents,kgCO2-eq/m3𝐶𝐸𝑆𝑁2𝑂−𝐶𝑆𝑂—Thenitrogencontentofoverflowedwastewateronaverageineventi,kgN/m3Theoverflowvolumeofwastewaterineventi,m3𝑇𝑁𝑂,𝑖—EmissionfactorofN2O,kgN2O-N/kgN.SeeTable5.5Q𝐶𝑆𝑂,𝑖—TheconversionofkgN2O-NintokgN2O𝐸𝐹𝑁2𝑂−𝐶𝑆𝑂—GlobalwarmingpotentialofN2O,265kgCO2-eq/kgN2O44/28—Totalwastewaterconveyancevolumeofthedrainagesystemintheinventoryyear,m3/a265—ThenumberofCSOeventintheinventoryyear—𝑄𝑦𝑛—Table5.5SummaryofN2OEFsofwastewaterbydischargepathway(IPCC,2019).DischargewaterbodyN2OEF(kgN2O-N/kgN)2Dischargetolakes,oceansandothernaturalwater0.005bodies1(0.0005~0.075)Dischargetonaturalwaterbodieswithexcess0.019nutrientsoroxygendeficiency(0.0041~0.091)1.Whenthereisnoinformationaboutdischargepathway,thiscanbereferredto.2.Forvalueprovidedarange,thevaluecanbetakenbasedonthewaterqualityofreceivingbody.Alowervalueisusedforhigh-qualitywater,andviceversa.5.4.2.4OtheremissionactivitiesInwastewatercollectionnetworks,iftherearesomewastewaterliftingpumpingstations,thecarbonemissionofpowerconsumptionshouldbeconsideredaswell,andtheaccountingmethodstorefertoareEquation(5.2)andEquation(5.3).5.4.3Wastewatertreatmentplants5.4.3.1FossilCO2emissions5.4.3.1.1WastewatertreatmentThebiotreatmentofwastewaterisperformedthroughthreeprocesses:endogenousdecay,BODoxidation,andnitrogenremoval.Inthesethreeprocesses,CO2isproducedandconsumed.Forexample,intheprocessofbiologicalammoniaremoval(nitrification),CO2isconsumedleadingtoaCO2credit.ItshouldbenotedthatonlyfossilCO2isincludedininventory.Inaddition,ifexternalcarbonsourceisdosedinthebiotreatmentofwastewater,theresultantCO2isincludedinfossilCO2.ThefossilCO2productioniscalculatedasEquation(5.21)–(5.23).50Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance𝐶𝐸𝑆𝑤𝑤=𝑀𝐹𝐶𝐹×{[1.1×(𝐵𝑂𝐷5𝑖𝑛+𝐵𝑂𝐷5𝑒𝑥−𝐵𝑂𝐷5𝑒𝑓𝑓)0.67(1.947𝐾𝑑)×(1.47−1.42×1+𝐾)]+×𝐻𝑅𝑇×𝑀𝐿𝑉𝑆𝑆××𝑆𝑅𝑇𝑑−4.49(5.21)×[(𝑇𝐾𝑁𝑖𝑛−𝑇𝐾𝑁𝑒𝑓𝑓)−（𝐵𝑂𝐷5𝑖𝑛+𝐵𝑂𝐷5𝑒𝑥0.67−𝐵𝑂𝐷5𝑒𝑓𝑓）×（1+𝐾×𝑆𝑅𝑇）×0.124]}×10−3𝑑𝑀𝐹𝐶𝐹=𝐹𝐶𝐹×𝐵𝑂𝐷5𝑖𝑛+𝐵𝑂𝐷5𝑒𝑥(5.22)𝐵𝑂𝐷5𝑖𝑛+𝐵𝑂𝐷5𝑒𝑥𝐾𝑑=0.05×1.04𝑇𝑏−20(5.23)Where:𝐶𝐸𝑆𝑤𝑤—EmissionintensityoffossilCO2inwastewatertreatmentplant,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicmatterinwastewater,%.SeeEquation(5.22)1.1—ConversionfactorofkgCODmineralizationtoCO2𝐵𝑂𝐷5𝑖𝑛—AverageinfluentBOD5concentrationofwastewatertreatmentplant,mgBOD5/L𝐵𝑂𝐷5𝑒𝑥—Dosagequantityofexternalcarbonsource,mgBOD5/L𝐵𝑂𝐷5𝑒𝑓𝑓—AverageeffluentBOD5concentrationofwastewatertreatmentplant,mgBOD5/LConversionfactorofBOD5toBOD1.47—ConversionfactorofkgbiomasstokgBOD,kgBOD/kgMLVSS1.42—Biomassyieldcoefficient,kgMLVSS/kgBOD50.67—Endogenousdecaycoefficient,d-1.SeeEquation(5.23)Sludgeretentiontime,d𝐾𝑑—ConversionfactorofdecayofkgbiomasstoCO2,kgCO2/kgMLVSS𝑆𝑅𝑇—Hydraulicretentiontime,d1.947—Concentrationofmixedliquidvolatilesuspendedsolids,mgMLVSS/L𝐻𝑅𝑇—kgCO2fixedbythenitrificationprocessofkgammonianitrogen,kgCO2/kgNH+4𝑀𝐿𝑉𝑆𝑆—4.49—-N𝑇𝐾𝑁𝑖𝑛—Averageinfluentkjeldahlnitrogenconcentrationofwastewatertreatmentplants,mgN/L𝑇𝐾𝑁𝑒𝑓𝑓—Averageeffluentkjeldahlnitrogenconcentrationofwastewatertreatmentplants,mgN/L0.124—Theamountofnitrogeninthebiomass,kgN/kgMLVSS𝐹𝐶𝐹—Proportionoffossilorganicmatterintotalorganicmatterinwastewater,%.5%~20%ingeneraland10%recommendedprovidednodata𝑇𝑏—Wastewatertemperature,°C5.4.3.1.2ConstructedwetlandsConstructedwetlandsaretreatmentsystemsthatusenaturalprocessesinvolvingwetlandvegetation,soils,andtheirassociatedmicrobialassemblagestoimprovewaterquality.Theyaregenerallyappliedforadvancedtreatmentofthesecondaryeffluentofwastewatertreatmentplantsandinevitably,greenhousegasisproducedandemitted.FossilCO2iscalculatedasEquation(5.24).51Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector1.1×𝐵𝑂𝐷5′𝑖𝑛𝐶𝐸𝑆𝐶𝐻4−𝑤𝑙(5.24)𝐶𝐸𝑆𝑤𝑙=𝑀𝐹𝐶𝐹×(44×103−28×16)×44Where:𝐶𝐸𝑆𝑤𝑙—EmissionintensityoffossilCO2inconstructedwetland,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicmatterinwastewater,%.SeeEquation(5.22)1.1—ConversionfactorofkgCODmineralizationtoCO2𝐵𝑂𝐷5′𝑖𝑛—AverageinfluentBOD5concentrationofconstructedwetland,mgBOD5/L44—ThemolecularmassofCO2,44g/mol28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH416—ThemolecularmassofCH4,16g/mol𝐶𝐸𝑆𝐶𝐻4−𝑤𝑙—EmissionintensityofCH4inconstructedwetland,kgCO2-eq/m3.SeeEquation(5.26)5.4.3.2CH4emissions5.4.3.2.1WastewatertreatmentInatypicalwastewatertreatmentplant,despitetheengineeredCH4productionpointssuchassludgeanaerobicdigestor,therearealsomanynaturalCH4productionpointsduetotheprevailinganaerobicconditionsincludingscreens,gritchambers,theprimaryclarifier,biologicaltreatmentunits,secondarysedimentationtanks,andsomeadvancedtreatmentunits.TheemissionfactormethodgenerallyusedtocalculatetheCH4emissionofthewastewatertreatmentplantisprovidedbythe2019Refinementtothe2006IPCCGuidelinesforNationalGreenhouseGasInventories(IPCC,2019).Meanwhile,aseriesofEFsareprovidedbasedonliteraturereviews.However,thereweresomeerrorsinprocessingthereferreddata,whichcompromisedtheaccuracyofEFsandthematchtoequation(seeAppendixB.6fordetails).Therefore,thisguidelinerevisestheequationandupdatestheassociatedemissionfactors.ItshouldbenotedthattheequationprovidedbyIPCCismorescientific(seeAppendixB.6fordetails)andisrecommendedonceEFshavebeenmodifiedandupdated.ThisguidelinerecommendstheEquation(5.25)(excludingtheleakageofCH4fromanaerobicdigestionofsludgetanks):𝐶𝐸𝑆𝐶𝐻4−𝑤𝑤=(𝐵𝑂𝐷5𝑖𝑛×𝐸𝐹𝐶𝐻4−𝑤𝑤−𝑀𝐶𝐻4−𝑇)×28×10−3(5.25)Where:𝐶𝐸𝑆𝐶𝐻4−𝑤𝑤—EmissionintensityofCH4inwastewatertreatmentplant,kgCO2-eq/m3𝐵𝑂𝐷—AverageinfluentBOD5concentrationofwastewatertreatmentplant,mg5𝑖𝑛BOD5/L𝐸𝐹𝐶𝐻4−𝑤𝑤—Emissionfactor,kgCH4/kgBOD5.SeeTable5.6𝑀𝐶𝐻4−𝑇—RecoveredorremovedamountofCH4,kgCH4/m328—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4Table5.6SummaryofCH4emissionfactorsbywastewatertreatmentprocess.TreatmentprocessCH4EFs(kgCH4/kgBOD5)IntegratedEmissionFactorCentralized,aerobictreatmentplant10.0121(0.000336~0.048)(General)0.0036(0.000336~0.0177)(Chinaspecific)52Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenanceAnaerobicreactor(suchasupflowanaerobic0.48sludgeblanketdigestion)2Anaerobicdeeplagoon0.5Anaerobicshallowlagoon0.125Aeratedaerobicpond0.018EmissionfactorsbydifferentprocessesAAO0.0142(7)3AO0.0083(7)Oxidationditch0.0096(4)SBR0.0100(3)Aerobictank0.0152(6)1.SeeAppendixB.6fordetails2.CitationfromIPCC(2019)3.Thenumbersinbracketsindicatetheamountofreferencedata,seeAppendixB.6fordetails5.4.3.2.2ConstructedwetlandCH4emissionfromconstructedwetlandiscalculatedasEquation(5.26).𝐶𝐸𝑆𝐶𝐻4−𝑤𝑙=𝐵𝑂𝐷5′𝑖𝑛×𝐸𝐹𝐶𝐻4−𝑤𝑙×28×10−3(5.26)Where:𝐶𝐸𝑆𝐶𝐻4−𝑤𝑙—EmissionintensityofCH4inconstructedwetland,kgCO2-eq/m3𝐵𝑂𝐷5′𝑖𝑛—AverageinfluentBOD5concentrationofconstructedwetland,mgBOD5/L𝐸𝐹𝐶𝐻4−𝑤𝑙—Emissionfactor,kgCH4/kgBOD5.SeeTable5.728—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4Table5.7SummaryofCH4EFsbydifferenttypeofconstructedwetland(IPCC,2019)CH4EFsTypekgCH4/kgBOD5kgCH4/kgCODDefaultsRangeDefaultsRangeSurfaceflowconstructed0.240.048~0.420.10.02~0.175wetlandHorizontalsubsurface0.060.042~0.0780.0250.0175~0.0325constructedwetlandVerticalsubsurface0.0060.0024~0.00960.00250.001~0.004constructedwetland5.4.3.2.3ReceivingwaterbodiesTheeffluentdischargedtoreceivingwaterbodiesstillcontainsasmallamountoforganicmatterwhichhasthepotentialtoproduceCH4.TheemissionfactormethodcanbeappliedtocalculateCH4emissionsasshowninEquation(5.27).𝐶𝐸𝑆𝐶𝐻4−𝑟𝑒=𝐵𝑂𝐷5′′𝑖𝑛×𝐸𝐹𝐶𝐻4−𝑟𝑒×28×10−3(5.27)Where:53Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝐶𝐸𝑆𝐶𝐻4−𝑟𝑒—EmissionintensityofCH4inreceivingwaterbody,kgCO2-eq/m3𝐵𝑂𝐷5′′𝑖𝑛—AverageBOD5concentrationofwastewaterdischargetoreceivingwaterbody,mgBOD5/L𝐸𝐹𝐶𝐻4−𝑟𝑒—Emissionfactor,kgCH4/kgBOD5.SeeTable5.4;28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH45.4.3.3N2Oemissions5.4.3.3.1WastewatertreatmentplantsInwastewatertreatmentplants,nitrogenremovalisacommontargetandachievedbythebiologicalnitrogenremovalprocess.Inthisprocess,N2Oisproducedfrommicrobialmediatednitrificationanddenitrificationwhichhavebeencategorizedintofourpathways.TheN2OemissionfromwastewatertreatmentplantsiscalculatedasEquation(5.28).𝐶𝐸𝑆𝑁2𝑂−𝑤𝑤=(𝑇𝑁𝑖𝑛×𝐸𝐹𝑁2𝑂−𝑤𝑤×44/28×10−3−𝑀𝑁2𝑂−𝑇)×265(5.28)Where:𝐶𝐸𝑆𝑁2𝑂−𝑤𝑤—EmissionintensityofN2Oinwastewatertreatmentplant,kgCO2-eq/m3𝑇𝑁𝑖𝑛—Averageinfluentkjeldahlnitrogenconcentrationofwastewatertreatmentplants,mgN/L𝐸𝐹𝑁2𝑂−𝑤𝑤—Emissionfactor,kgN2O-N/kgN.SeeTable5.8𝑀𝑁2𝑂−𝑇—RecoveredorremovedamountofN2O,kgN2O/m344/28—TheconversionofkgN2O-NintokgN2O265—GlobalwarmingpotentialofN2O,kgCO2-eq/kgN2OTable5.8SummaryofN2OEFsbywastewatertreatmentprocessTreatmentprocessN2OEFs(kgN2O-N/kgN)IntegratedEmissionFactorCentralized,aerobictreatmentplant10.0093(General)0.0106(Chinaspecific)Anaerobicreactor(suchasupflowanaerobic0sludgeblanketdigestion)2Anaerobicdeeplagoon0Anaerobicshallowlagoon00.001Aeratedaerobicpond200.001EmissionfactorsbydifferentprocessesAAO0.00466(9)3AO0.00680(27)Oxidationditch0.00641(13)SBR0.02020(11)Aerationtank0.00166(10)Short-cutnitrification-ANAMMOX0.02000(1)AerobicGranularSludge0.00330(1)1.SeeAppendixB.7fordetails54Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance2.CitationfromIPCC,20193.Thenumbersinbracketsindicatetheamountofreferencedata,andseeAppendixB.7fordetails5.4.3.3.2ConstructedwetlandN2OemissionfromconstructedwetlandiscalculatedasEquation(5.29).𝐶𝐸𝑆𝑁2𝑂−𝑤𝑙=𝑇𝑁𝑒′𝑓𝑓×𝐸𝐹𝑁2𝑂−𝑤𝑙×44/28×265×10−3(5.29)Where:𝐶𝐸𝑆𝑁2𝑂−𝑤𝑙—EmissionintensityofN2Oinconstructedwetland,kgCO2-eq/m3𝑇𝑁𝑒′𝑓𝑓—Averageinfluentnitrogenconcentrationofconstructedwetland,mgN/L𝐸𝐹𝑁2𝑂−𝑤𝑙—Emissionfactor,kgN2O-N/kgN.SeeTable5.944/28—TheconversionofkgN2O-NintokgN2O265—GlobalwarmingpotentialofN2O,kgCO2-eq/kgN2OTable5.9SummaryofN2OEFsbydifferenttypeofconstructedwetland(IPCC,2019)TypeN2OEFs(kgN2O-N/kgN)Surfaceflowconstructedwetland0.0013Horizontalsubsurfaceconstructedwetland0.0079Verticalsubsurfaceconstructedwetland0.000235.4.3.3.3ReceivingwaterbodyEmissionfactormethodcanbeappliedtocalculateN2OemissionasEquation(5.30).𝐶𝐸𝑆𝑁2O−𝑟𝑒=𝑇𝑁𝑒′𝑓′𝑓×𝐸𝐹𝑁2O−𝑟𝑒×44/28×265×10−3(5.30)Where:𝐶𝐸𝑆𝑁2O−𝑟𝑒—EmissionintensityofN2Oinreceivingwaterbody,kgCO2-eq/m3𝑇𝑁𝑒′𝑓′𝑓—Averagenitrogenconcentrationofwastewaterdischargetoreceivingwaterbody,mgN/L𝐸𝐹𝑁2O−𝑟𝑒—EFs,kgN2O-N/kgN.SeeTable5.544/28—TheconversionofkgN2O-NintokgN2O265—GlobalwarmingpotentialofN2O,kgCO2-eq/kgN2O5.4.3.4OtheremissionsTheGHGemissionsfromfossilfuel,electricity,material/chemicalconsumption,andtransportationforchemicalsand/orsludgedisposalarecalculatedaccordingtoSection5.2.5.4.3.5Carbonreductionbyresource/energyrecovery5.4.3.5.1CarbonoffsetbyenergyrecoveryWastewaterisrichinchemicalandthermalenergywhichcanberecoveredbyanaerobicdigestion-CHPandheatpumpstooffsetcarbonemissionsofthewastewatermanagementsystem.Whentherecoveredenergyisexported,thecarbonoffsetshouldbeconsideredandcalculatedwithEquation(5.31)and(5.32).55Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝐶𝑆𝑆𝑒=𝐸𝑐𝑠−𝑑×𝐸𝐹𝑑/𝑄𝑖𝑛(5.31)Where:𝐶𝑆𝑆𝑒—Carbonoffsetofelectricityproduction,kgCO2-eq/m3𝐸𝑐𝑠−𝑑—Thetotalelectricityexportedintheinventoryyear,kWh/a𝐸𝐹𝑑—TheEFsofelectricityreplacedbytheexportedelectricity,kgCO2-eq/kWh.SeeAppendixB.2;𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a𝐶𝑆𝑆ℎ=𝐸𝑐𝑠−ℎ×𝐸𝐹ℎ/𝑄𝑖𝑛(5.32)Where:𝐶𝑆𝑆ℎ—Carbonoffsetforheatrecovery,kgCO2-eq/m3𝐸𝑐𝑠−ℎ—Thetotalthermalenergyexportedintheinventoryyear,GJ/a𝐸𝐹ℎ—EFsofheatreplacedbytheexportedheat,kgCO2/GJ.SeeAppendixB.1𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a5.4.3.5.2CarbonoffsetfromresourcerecoveryThereareabundantresourcesinwastewaterandmanytechnologieshavebeenproposedandpracticedinfull-scaleprojectstorecoveravarietyofproducts.Forexample,phosphorusinwastewatercanberecoveredviastruviteorvivianite,whichareatypeoffertilizerandahighvalue-addedmaterial,respectively.TheseproductscanbesubstitutedforindustrialproductstoinducecarbonoffsetandcanbecalculatedwithEquation(5.33).𝑛(5.33)𝐶𝑆𝑆𝑟𝑒=∑𝑀𝑟𝑒,𝑖×𝐸𝐹𝑟𝑒,𝑖/𝑄𝑖𝑛𝑖=1Where:𝐶𝑆𝑆𝑟𝑒𝑠—Carbonoffsetofresourcerecovery,kgCO2-eq/m3𝑛—Thenumberofproducttypesrecoveredintheinventoryyear𝑀𝑟𝑒,𝑖—Theindustrialproductequivalentoftherecoveredproductiintheinventoryyear,kg/kg𝐸𝐹𝑟𝑒,𝑖—EFsoftheindustrialproductreplacedbyrecoveredproducti,kgCO2/kg𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a5.4.3.5.3OthercarbonsinkWhenconstructedwetlandsareappliedforadvancedpurificationofeffluent,thevegetationand/orplantscanbecarbonsinks.TheresultingcarboncreditcanbecalculatedwithEquation(5.34).𝐶𝑆𝑆𝑧𝑏=𝐸𝐹𝑧𝑏×𝑆𝑧𝑏(5.34)Where:𝐶𝑆𝑆𝑧𝑏—Carbonsinkofplantcarbonsequestration,kgCO2-eq𝐸𝐹𝑧𝑏—Carbonfixationcapacityofplants,kgCO2-eq/m2.SeeAppendixB.8𝑆𝑧𝑏—Plantcoveragearea,m256Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance5.4.4SludgeTreatmentandDisposal5.4.4.1FossilCO2emission5.4.4.1.1AnaerobicdigestionTheanaerobicdigestionprocessiswidelyappliedinwastewatertreatmentplanttostabilizeandvalorizewastesludge.Inthisprocess,CH4-richbiogasisproducedandfuelsthecombinedheatandpower(CHP)neededforelectricitygeneration.ItmeansthegreenhousegasemittedfromanaerobicdigestionisintheformofCO2releasedintotheatmosphere.Asmentionedabove,partoftheorganicmatterininfluentisfossilorganicmatterandpartoftheCO2releasedwillbeabiogenic.TheGuidelinesprovidestwoaccountingmethodsforfossilCO2quantification.Method1isbasedonmassbalanceandmethod2assumesthatthevolumeofbiogasisavailable.TheequationsforthetwomethodsarelistedasshowninEquation(5.35-5.36):Method1:𝐶𝐸𝑆=𝑀𝐹𝐶𝐹×[(1−P)×44×𝐹𝐶𝐻4+44−44×𝐹𝐶𝐻4]×𝑄𝑎𝑑44−28×𝐹𝐶𝐻444−28×𝐹𝐶𝐻4𝑠𝑠(5.35)×(𝑉𝑆𝑆𝑜−𝑎𝑑−𝑉𝑆𝑆𝑒−𝑎𝑑)/𝑄𝑖𝑛Where:𝐶𝐸𝑆𝑎𝑑—emissionintensityoffossilCO2inanaerobicdigestion,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicmatterinwastewater,%.SeeEquation(5.22)𝑃—Theproportionofbiogasleakage,%.SeeTable5.1044—themolecularmassofCO2,44g/mol𝐹𝐶𝐻4—ProportionofCH4inbiogas,%28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH4𝑄𝑠𝑠—thevolumeofwastesludgeenteringanaerobicdigestorintheinventoryyear,m3/a𝑉𝑆𝑆𝑜−𝑎𝑑—theamountofvolatilesuspendedsolidintheinfluent,kgVSS/m3𝑉𝑆𝑆𝑒−𝑎𝑑—theamountofvolatilesuspendedsolidintheeffluent,kgVSS/m3𝑄𝑖𝑛—thetotalamountofwastewatertreatedintheinventoryyear,m3/aMethod2:𝑀𝐹𝐶𝐹×𝑀𝑧𝑞(5.36)𝐶𝐸𝑆𝑎𝑑=(1−P)×22.4×𝑄𝑖𝑛×44Where:𝐶𝐸𝑆𝐶𝐻4−𝑎𝑑—EmissionintensityoffossilCO2inanaerobicdigestion,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicmatterinwastewater,%.SeeEquation(5.22)𝑀𝑧𝑞—Theamountofbiogascollectedintheinventoryyear,m3/a𝐹𝐶𝐻4—ProportionofCH4inbiogas,%22.4—ThevolumeofonemoleofagasatSTP𝑃—Theproportionofbiogasleakage,%.SeeTable5.10𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a44—ThemolecularmassofCO2,44g/mol57Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable5.10Summaryofbiogasleakageratiobydifferentconditionsofanaerobicdigester(IPCC,2019).QualityofdigesterConditionsforClimatezonestorageCooltemperateWarmtemperateHighgastight1.00%1.00%highqualityPoorgastight1.41%1.41%average1.99%2.27%Highgastight9.59%9.59%lowqualityPoorgastight10.00%10.00%average10.58%10.85%5.4.4.1.2AerobiccompostingIntheprocessofaerobiccompostingofwastesludge,organicmattercanbemineralizedtoCO2partofwhichisfossilCO2.ItcanbecalculatedasEquation(5.37).𝐶𝐸𝑆𝑐=𝑀𝐹𝐶𝐹×𝑀𝑠𝑠×𝐷𝑂𝐶×𝐷𝑂𝐶𝑓−𝑐×44/12/𝑄𝑖𝑛(5.37)Where:𝐶𝐸𝑆𝑐—EmissionintensityoffossilCO2inaerobiccomposting,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicmatterinwastewater,%.SeeEquation(5.22)𝑀𝑠𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝐷𝑂𝐶—Degradableorganiccarbon,kgC/kgTS𝐷𝑂𝐶𝑓−𝑐—FractionofDOCthatdecompose,%44/12—MolecularmassratioofCO2andC𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a5.4.4.1.3LandfillWhensludgeisdisposedinalandfill,CO2andCH4canbeproduced.TheequationforfossilCO2calculationislistedasEquation(5.38).𝐶𝐸𝑆𝑠𝑙=𝑀𝐹𝐶𝐹×𝑀𝑠𝑠×𝐷𝑂𝐶×𝐷𝑂𝐶𝑓×（1−𝑀𝐶𝐹×𝐹）×44/12/𝑄𝑖𝑛(5.38)Where:matterin𝐶𝐸𝑆𝑠𝑙—EmissionintensityoffossilCO2inlandfill,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicwastewater,%.SeeEquation(5.22)𝑀𝑠𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝐷𝑂𝐶—Degradableorganiccarbon,kgC/kgTS𝐷𝑂𝐶𝑓—FractionofDOCthatdecompose,%𝑀𝐶𝐹—Correctionfactor.Defaultis1𝐹—ProportionofCH4inreleasedgas,%.Defaultis50%44/12—MolecularmassratioofCO2andC𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a58Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance5.4.4.1.4SludgeincinerationTheequationforfossilCO2calculationfromsludgeincinerationislistedasEquation(5.39).𝐶𝐸𝑆𝑖𝑛=𝑀𝐹𝐶𝐹×𝑀𝑠𝑠×𝐶𝐹×𝑂𝐹×44/12/𝑄𝑖𝑛(5.39)matterinWhere:𝐶𝐸𝑆𝑖𝑛—EmissionintensityoffossilCO2inincineration,kgCO2-eq/m3𝑀𝐹𝐶𝐹—Modifiedproportionoffossilorganicmatterintotalorganicwastewater,%.SeeEquation(5.22)𝑀𝑠𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝐶𝐹—Totalcarboncontentpercentage,%𝑂𝐹—Defaultis100%inawell-managedincinerator44/12—MolecularmassratioofCO2andC𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a5.4.4.2CH4emissions5.4.4.2.1AnaerobicdigestionIntheanaerobicdigestionprocess,asmallquantityofCH4mayescapethereactorduetothequalityofgastightconditions.TheGuidelinesprovidestwoaccountingmethodsofaccountingfortheCH4leakage.Method1isbasedonmassbalanceandMethod2assumesthatthevolumeofbiogasisavailable.TheequationsforthetwomethodsarelistedasEquation(5.40)andEquation(5.41).Method1:𝐶𝐸𝑆𝐶𝐻4−𝑎𝑑=𝑃×[𝑄×(𝑉𝑆𝑆−𝑉𝑆𝑆)×16×𝐹𝐶𝐻4]/𝑄×28(5.40)𝑠𝑠𝑜−𝑎𝑑𝑒−𝑎𝑑44−28×𝐹𝐶𝐻4𝑖𝑛Where:𝐶𝐸𝑆𝐶𝐻4−𝑎𝑑—EmissionintensityofCH4leakageinanaerobicdigestion,kgCO2-eq/m3𝑃—Theproportionofbiogasleakage,%.SeeTable5.10𝑄𝑠𝑠—Thevolumeofwastesludgeenteringanaerobicdigestorintheinventoryyear,m3/a𝑉𝑆𝑆𝑜−𝑎𝑑—Theamountofvolatilesuspendedsolidsintheinfluent,kgVSS/m3𝑉𝑆𝑆𝑒−𝑎𝑑—Theamountofvolatilesuspendedsolidsintheeffluent,kgVSS/m344—ThemolecularmassofCO2,44g/mol28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH416—ThemolecularmassofCH4,16g/mol𝐹𝐶𝐻4—ProportionofCH4inbiogas,%𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/aMethod2:𝐶𝐸𝑆𝐶𝐻4−𝑎𝑑=𝑀𝑧𝑞×𝐹𝐶𝐻4/22.4×P/(1−P)/𝑄𝑖𝑛×16×28(5.41)Where:𝐶𝐸𝑆𝐶𝐻4−𝑎𝑑—EmissionintensityofCH4leakageinanaerobicdigestion,kgCO2-eq/m3𝑀𝑧𝑞—Theamountofbiogascollectedintheinventoryyear,m3/a𝐹𝐶𝐻4—ProportionofCH4inbiogas,%22.4—ThevolumeofonemoleofagasatSTP𝑃—Theproportionofbiogasleakage,%.SeeTable5.1059Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a16—ThemolecularmassofCH4,16g/mol28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH45.4.4.2.2LandfillTheequationforCH4emissionfromlandfillislistedasEquation(5.42).𝐶𝐸𝑆𝐶𝐻4−𝑠𝑙=𝑀𝑠𝑠×𝐷𝑂𝐶×𝐷𝑂𝐶𝑓×𝑀𝐶𝐹×𝐹×(1−𝑂𝑋)×16/12/𝑄𝑖𝑛×28(5.42)Where:𝐶𝐸𝑆𝐶𝐻4−𝑠𝑙—EmissionintensityofCH4inlandfill,kgCO2-eq/m3𝑀𝑠𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝐷𝑂𝐶—Degradableorganiccarbon,kgC/kgTS𝐷𝑂𝐶𝑓−𝑐—FractionofDOCthatdecompose,%𝑀𝐶𝐹—Correctionfactor.Defaultis1𝐹—ProportionofCH4inreleasedgas,%.Defaultis50%𝑂𝑋—TheratioofCH4beingoxidizedbeforeescapingintotheatmosphere.Defaultvalue(whenwellmanagedandcoveredwithbreathablematerial)is0.1,or(whennothandledproperly)0(IPCC,2019)16/12—MolecularmassratioofCH4andC𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH45.4.4.2.3LandapplicationEmissionsofCH4canoccurfromthedisposalofsludgetolandandcanbecalculatedbyEquation(5.43).𝐶𝐸𝑆𝐶𝐻4−𝑙𝑎=𝐸𝐹𝐶𝐻4−𝑙𝑎×𝑀𝑠𝑠/𝑄𝑖𝑛×28(5.43)Where:𝐶𝐸𝑆𝐶𝐻4−𝑙𝑎—EmissionintensityofCH4inlandapplication,kgCO2-eq/m3𝐸𝐹𝐶𝐻4−𝑙𝑎—Emissionfactor,kgCH4/kgTS.Defaultis0.00318(IPCC,2019)𝑀𝑠𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a28—GlobalwarmingpotentialofCH4,28kgCO2-eq/kgCH45.4.4.3N2Oemissions5.4.4.3.1AerobiccompostingEmissionsofN2OcanoccurfromtheaerobiccompostingofsludgeduetothebiochemicaltransformationofnitrogencompoundsandcanbecalculatedbyEquation(5.44).𝐶𝐸𝑆𝑁2𝑂−𝑐=𝑀𝑠′𝑠×𝐸𝐹𝑁2𝑂−𝑐/𝑄𝑖𝑛×265(5.44)Where:𝐶𝐸𝑆𝑁2𝑂−𝑐—EmissionintensityoffossilCO2inaerobiccomposting,kgCO2-eq/m3𝑀𝑠′𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝐸𝐹𝑁2𝑂−𝑐—EFs,kgN2O/kgTS.Defaultis0.2~1.6×10-3kgN2O/kgTS(IPCC,2019)𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a265—GlobalwarmingpotentialofN2O,kgCO2-eq/kgN2O60Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance5.4.4.3.2SludgeincinerationThecalculationforN2OproductionintheincinerationprocessislistedasEquation(5.45).𝐶𝐸𝑆𝑁2𝑂−𝑖𝑛=𝑀𝑠𝑠×𝐸𝐹𝑁2𝑂−𝑖𝑛/𝑄𝑖𝑛×265×10−3(5.45)Where:𝐶𝐸𝑆𝑁2𝑂−𝑖𝑛—EmissionintensityofN2Oinincineration,kgCO2-eq/m3𝑀𝑠𝑠—Totaldrysolidofwastesludgeintheinventoryyear,kgTS/a𝐸𝐹𝑁2𝑂−𝑖𝑛—EFs,kgN2O/tTS.Defaultis0.99kgN2O/tTS(IPCC,2019)𝑄𝑖𝑛—Thetotalamountofwastewatertreatedintheinventoryyear,m3/a265—GlobalwarmingpotentialofN2O,kgCO2-eq/kgN2O5.5WATERRECLAMATIONSYSTEMS5.5.1AccountingboundaryThewaterreclamationsystemisaprocessofreclaimingandpurifyingwastewaterintoareusableform.AsshowninFigure5.4,theorganizationalboundaryofthewaterreclamationsystemcoversallrelevantfacilitiesfromtheoutletofthewastewatertreatmentplanttotheuser,includingtreatmentfacilitiesanddistributionnetwork.ThecarbonemissionactivitiesandemissiontypesaresummarizedinTable5.11.Figure5.4Schematicdiagramoftheorganizationalboundaryofwaterreclamationsystems.61Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable5.11Carbonemissionactivitiesofwaterreclamationsystem.Scope(carbonemissionType(ISO14064-1:2018)AdvancedtreatmentplantWaterdistributionnetworkprotocol)DirectGHGemissionsproducedatfacilitiesand/orDirectGHGemissionsandFossilfuelconsumptionassetsownedbythewaterremovalssectorsIndirectGHGemissionsincurredbyanenergyIndirectGHGemissionsfromElectricityconsumptionbytreatmentunitsElectricityconsumptionbydistributionpumpsproviderwhenproducingtheimportedenergyenergypurchasedbythewatersectorsIndirectGHGemissionsfromTransportationformaterials,chemicalsinput,by-productsoutput,etc.transportationIndirectGHGemissionsfromMaterialandchemicalconsumptionMaterialandchemicalconsumptionOtherindirectGHGproductsusedbyorganizationemissionsnotattributabletoIndirectGHGemissionsenergyassociatedwiththeuseofDisposalofsludge-productsfromtheorganizationsIndirectGHGemissionsfrom--othersources62Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance5.5.2AdvancedtreatmentplantsAdvancedtreatmentplantsmainlyreceivesecondaryeffluentofwastewatertreatmentplantsandpurifytheeffluentfurtherforgroundwaterrecharging,industrialandagriculturalreuse,andlandscapeirrigation.Generally,aflexiblecombinationoftreatmentprocessescanbeexclusivelydesignedaccordingtothereusepurpose,includingcoagulation,precipitation,andfiltration.Inaddition,advancedtreatmentunits,suchasmembraneseparationandadvancedoxidation,canalsobeaddedtoachievehighwaterqualitystandard.Thecarbonemissionactivitiesofwaterreclamationsystemaresimilartothoseofwatersupplysystems,primarilyincludingelectricityconsumption,chemicalusage,andtransportation.5.5.2.1IndirectcarbonemissionofelectricityconsumptionThecarbonemissionfromimportedelectricityconsumptionforadvancedtreatmentplantcanrefertoEquation(5.2)and(5.3).5.5.2.2IndirectcarbonemissionofmaterialconsumptionTheindirectcarbonemissionofthematerialsconsumptionforadvancedtreatmentplantcanrefertoEquation(5.4).5.5.2.3IndirectcarbonemissionoftransportationTheindirectcarbonemissionfromthetransportationofchemicalimportorsludgeexportintheadvancedtreatmentplantcanrefertoEquation(5.5).5.5.2.4SludgedisposalIftheorganiccontentinsludgeproducedfromtheadvancedtreatmentprocessesisrelativelylarge,CH4canbeproducedbytheanaerobicfermentationoforganicmatterwhichcanbecalculatedbyEquation(5.7).5.5.3WaterdistributionnetworkThecarbonemissionfromtheconsumptionofimportedelectricityforvarioustreatmentprocessescanbecalculatedaccordingtoEquation(5.2)and(5.3).5.6STORMWATERSYSTEMS5.6.1AccountingboundaryThestormwatersystemisanurbanconstructionmodeltoabsorbrainandpreventflooding.Itiscomposedofavarietyoffacilitiesandmodulestakingthefunctionsofstormwaterinfiltration,transmission,retentionanddetention,storage,pollutioninterception,purificationandutilization,respectively.Itcanbedividedintotwomodules,stormwatersewersandstormwatercontrolfacilities.Thereinto,stormwatersewersincludeconventionaldrainagepipesandplantedditches/infiltrationpipes.Stormwatercontrolfacilitiescanbedividedintofivecategories,includingdetentionandretentionfacilities,harvestingandutilizationfacilities,detentionandstoragefacilities,interceptionandpurificationfacilitiesandothertechnicalfacilities.AsshowninFigure5.5,theorganizationalboundaryofcarbonemissionofthestormwatersystemcoversallfacilityunitsfromthedischargeofrainwatersourcetothedischargeintonaturalwaterbodies,includingdrainagepipes,pumpingstationsandothertransferfacilitiesinstormwaterpipefacilities,andgreenandgrayinfrastructuresinstormwatercontrolfacilities.ThespecificcarbonemissionactivitiesandemissioncategoriesaresummarizedinTable5.12.63Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure5.5Schematicdiagramofthecarbonemissionaccountingboundaryofthestormwatersystem.64Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenanceTable5.12Summaryofcarbonemissionsactivitiesofstormwatersystem.Scope(carbonCategory(ISO14064-1:StormwatersewersStormwatercontrolfacilitiesemissionaccounting2018)system)DirectGHGemissionsFossilfuelconsumptionproducedatfacilitiesand/orassetsownedbytheDirectGHGemissionsandwatersectorsremovalsIndirectGHGemissionsIndirectGHGemissionsfrom-CH4emissionfromstormwaterwetland,storagepond,bioretentionsystem.Besides,carbonremovalincurredbyanenergyimportedenergybyplantsequestrationproviderwhenproducingtheenergypurchasedbythewatersectorsOtherindirectGHGIndirectGHGemissionsfromElectricconsumptionbypumpsorirrigationElectricityconsumptionbypurificationandemissionsnotattributabletransportationhydraulicgiantutilizationfacilitiestoenergyOtherindirectgreenhouseIndirectGHGemissionsfromtransportationformaterials,chemicalsinput,by-productsoutput,etc.gasemissionscausedbyproductsusedbyorganizationtheactivitiesoftheIndirectGHGemissionsaccountingsubjectbutassociatedwiththeuseofMaterialconsumptionoutsideitsaccountingproductsfromtheorganizationsboundaryIndirectGHGemissionsfrom--DirectGHGemissionsothersourcesproducedatfacilitiesDirectGHGemissionsandand/orassetsownedbytheremovals--watersectors65Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector5.6.2Stormwatersewers5.6.2.1Drainagepipesandancillarystructure5.6.2.1.1DirectcarbonemissionoffossilfuelInstormwaterdrainagepipesandancillarystructures(pumpingstations,etc.),somemechanicalequipmentconsumesgasolineanddieselfossilfuelsduringoperation,thusgeneratingacertainamountofdirectcarbonemission.ThecalculationcanrefertoEquation(5.1).Intermsofstormwaterpumpingstations,carbonemissionsduetotheconsumptionoffossilfuelscanbecalculatedaccordingtoEquation(5.46)–(5.48).𝐶𝐸𝑆𝑟𝑙=𝑊𝑟𝑙×𝐸𝐹𝑟𝑙×10−9(5.46)𝑛𝜌𝑔（𝐻𝑛𝑒𝑡+𝐻𝑙𝑜𝑠𝑠)(5.47)𝑊𝑟𝑙=∑𝑖=1𝜂𝑖𝑣2(5.48)𝐻𝑙𝑜𝑠𝑠=0.00124×𝑑1.33×𝐿Where:𝐶𝐸𝑟𝑙—Carbonemissionintensityoffossilfuelconsumptionforwaterliftingordelivery,kgCO2-eq/m3𝑊𝑟𝑙—Energyconsumptionofusingoilpumpstotransportstormwatertonaturalwaterbodiesorsewagetreatmentplants,J/m3𝐸𝐹𝑟𝑙—TheEFsoffossilfuel,kgCO2-eq/GJ.SeeAppendixB.1𝜌—Rainwaterdensity,kg/m3.Defaultis1,000kg/m3𝑔—Accelerationofgravity.Defaultis9.8m/s2𝐻𝑛𝑒𝑡—Elevationdifferencebetweenthestartandendpointsofwaterdelivery,m𝐻𝑙𝑜𝑠𝑠—Thehydrauliclossalongthepipenetwork,m𝜂𝑖—Unitefficiencyoftypeipump,%𝑛—Atotalofpumpunitswithdifferentworkingefficiencyareused𝑣—Velocity,m/s𝑑—Waterpipelinediameter,m𝐿—Thelengthofthewaterpipeline,m5.6.2.1.2IndirectcarbonemissionofelectricityconsumptionTheelectricityconsumptioninthewaterpumpingprocessand/orfromlandscapelightingalsoleadstocarbonemission,whichcanbecalculatedbyuseofMethod1(Equation(5.49)).Intheabsenceoftotalelectricityconsumptiondata,carbonemissionscanbecalculatedaccordingtoMethod2(Equation(5.50)and(5.51)).Method1:𝐶𝐸d=𝐸𝐻×𝐸𝐹𝑑/𝑄(5.49)Where:𝐶𝐸d—Carbonemissionintensityofthestormwatersystempurchasedelectricity,kgCO2-eq/m3𝐸𝐻—Theannualpowerconsumptionofpumpingstationsystemoftherainwaterpipenetwork,kWh/a66Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance𝐸𝐹𝑑—EFsofelectricity,kgCO2-eq/kWh.SeeAppendixB.2𝑄—Thetotalamountofrainwatertransportedduringtheyear,m3/aMethod2:(5.50)𝐶𝐸𝑑=𝐸𝑑×𝐸𝐹𝑑(5.51)𝑛𝜌𝑔（𝐻𝑛𝑒𝑡+𝐻𝑙𝑜𝑠𝑠)𝐸𝑑=∑𝑖=13.6×106×𝜂𝑖Where:𝐶𝐸𝑑—Carbonemissionintensityofelectricityconsumptionforwaterfetchingorwaterdelivery,kgCO2-eq/m3𝐸𝑑—Energyconsumptiongeneratedbyusingelectricpumpstotransportunitwatertonaturalwaterbodiesorsewagetreatmentplants,kWh/m3𝐸𝐹𝑑—EFsofelectricity,kgCO2-eq/kWh.SeeAppendixB.2𝑀𝑟𝑙,𝑖—Evaluatethetotalamountoffossilfuel𝑖consumedduringtheyear,kg/aorm3/a𝜌—TheEFsoffossilfuel𝑖,kgCO2-eq/kgorkgCO2-eq/m3.SeeAppendixB.1𝑔—Accelerationofgravity,9.8m/s2𝐻𝑛𝑒𝑡—Elevationdifferencebetweenthestartandendpointsofwaterdelivery,m𝐻𝑙𝑜𝑠𝑠—Thehydrauliclossalongthepipenetwork,m,whichcanbecalculatedbyEquation(5.48)𝜂𝑖—Unitefficiencyoftypeipump,%𝑛—Atotalofpumpunitswithdifferentworkingefficiencyareused5.6.2.2Othertransferfacilities5.6.2.2.1IndirectcarbonemissionofelectricityconsumptionThecalculationofcarbonemissionsfromelectricityconsumptionbyothergreenconveyancefacilitiescanrefertoEquation(5.46)–(5.48).5.6.2.2.2CarbonremovalbygreeninfrastructuresPlantsandsoilsingreeninfrastructurescansequesterGHG,suchasgreenroofs,raingardens,lowelevationgreenbeltandothervegetation-containingfacilities.TheamountofcarboncreditbyvegetationiscalculatedbyEquation(5.52).𝐶𝑆zb=𝐸𝐹zb×𝑆zb(5.52)Where:𝐶𝑆zb—Carbonsinkcapacityofvegetation,kgCO2-eq𝐸𝐹zb—Vegetationcarbonsequestrationfactor,kgCO2-eq/m2.SeeAppendixB.8Vegetationarea,m2𝑆zb—5.6.3Stormwatercontrolfacilities5.6.3.1DetentionandretentionfacilitiesCarbonemissionsfromtheoperationandmaintenanceofdetentionandretentionfacilitiesincludeindirectemissionsfromimportedelectricityandcarbonsinksofvegetationingreeninfrastructureswhicharecalculatedaccordingtoSection5.6.2.2.67Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector5.6.3.2HarvestingandutilizationfacilitiesCarbonemissionfromharvestingandutilizationfacilitiesincludesindirectemissionsfromimportedelectricitywhichiscalculatedbyEquation(5.2)and(5.3).5.6.3.3DetentionandstoragefacilitiesCarbonemissionsfromthedetentionandstoragefacilitiesincludeindirectemissionsfromimportedelectricity,carbonremovalbyvegetationingreeninfrastructures,anddirectgreenhousegasemissionsfromstormwaterwetlandswhicharecalculatedaccordingtoSection5.6.2.2.Inaddition,asanimportantfacilityforimprovingwaterqualityinstormwatercontrolsystem,stormwaterwetlandprobablyproducesCH4andN2Oemissions.Thecarbonemissionmechanismofstormwaterwetlandsarecomplex,andtheemissionrateandamountareaffectedbyvariousfactorssuchasstability,plants,soilbackgroundvalue,andwaterflowmode(Table5.13).Forsimplicity,thisGuidelinesonlyconsidersthecarbonemissionsproducedbywetlandsduetoreceivingstormwater.Table5.13FactorsaffectingCH4andN2Oemissionsinstormwaterwetland.Factor/processCH4N2OIncreaseoftemperatureofIncreaseinalmostallcasesNorelationshipwater/soil/airElevatedmoistureinthesoilorfiltermaterialObviousincreaseReduction(increasedsoilporewatercontent)IncreasedrunoffofcollectedrainwaterIncreaseIncreasePlantswithaeratedleavesAsthecasemaybeAsthecasemaybeFluctuatinghydrologicalregimeSignificantreductionAsthecasemaybe(intermittentloading)GroundwaterleveldeepeninginReductionIncreasehorizontalflowconstructedwetlands5.6.3.3.1CH4emissionCH4emissionfromstormwaterwetlandsiscalculatedbyEquation(5.53)and(5.54).𝑛(5.53)𝐶𝐸𝐶𝐻4=∑(𝑇𝑂𝑊𝑖×𝐸𝐹𝐶𝐻4𝑖)×28𝑖=1𝑇𝑂𝑊i=𝐶𝑂𝐷i𝑊i365(5.54)Where:𝐶𝐸CH4—AnnualcarbonemissionofCH4convertedintoCO2equivalentfromstormwaterwetlands,kgCO2-eq/a𝑇𝑂𝑊i—TotalCODofrainwaterenteringtype𝑖stormwaterwetlandeachyear,kgCOD/a.CalculatedbyEquation(5.55)𝐸𝐹CH4—EmissionfactorofCH4inthestormwaterwetland𝑖,kgCH4/kgCOD.SeeTable5.7𝑖—Stormwaterwetlandtype28—GlobalwarmingpotentialconstantofCH4,28kgCO2-eq/kgCH468Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestOperationandmaintenance𝐶𝑂𝐷i—TheaverageCODconcentrationofrainwaterenteringtype𝑖stormwaterwetlandeachyear,kgCOD/m3𝑊i𝑖—Thedailystormwatercapacityoftype𝑖stormwaterwetland,m3/d—Stormwaterwetlandtype5.6.3.3.2N2OemissionN2OemissionfromstormwaterwetlandarecalculatedbyEquation(5.55).n(5.55)𝐶𝐸N2O=∑(𝑁i×𝐸𝐹N2O×44/28)×265i=1Where:𝐶𝐸N2O—AnnualcarbonemissionsofN2OconvertedintoCO2equivalentfromstormwaterwetlands,kgCO2-eq/a𝑁i—Totalnitrogenofrainwaterenteringtype𝑖stormwaterwetlandeachyear,kgN/a𝐸𝐹N2O—EmissionfactorsofN2Ointhestormwaterwetland𝑖,kgN2O-N/kgN.SeeTable5.9𝑖—Stormwaterwetlandtype265—GlobalwarmingpotentialconstantofN2O,265kgCO2-eq/kgN2O44/28—TheconversionofkgN2O-NintokgN2O5.6.3.4InterceptionandpurificationfacilitiesCarbonemissionsfromtheinterceptionandpurificationfacilitiesincludeindirectemissionsfromimportedelectricity,andcarbonremovalfromvegetationingreeninfrastructureswhicharecalculatedaccordingtoSection5.6.2-5.6.3.5.6.3.5OthergreenfacilitiesTheaccountingmethodofcarbonemissionsfromtheothergreeninfrastructurescanrefertoSection5.6.2-5.6.3.69Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter6Assetreplacementanddemolition6.1OVERVIEWThemaincarbonemissionactivitiesoftheurbanwatersectorintheassetreplacementanddemolitionstageinclude:i)directcarbonemissionsgeneratedbyburningfossilfuels;ii)indirectcarbonemissionsfromtheconsumptionofimportedelectricity;iii)indirectcarbonemissionsfromthetransportationofbuildingwaste.Inaddition,buildingwasteproducedintheassetreplacementanddemolitionstagecanberecycledandreused(suchassteelbars,etc.)whichcanthenproducecarboncreditandoffsetcarbonemissions.Astheactivitiesinplanningandconstructionfordifferentsystemsareconsistent,theaccountingequationsprovidedinthissectionareapplicabletoanysystemintheurbanwatersectors.6.2DIRECTEMISSIONSOFFOSSILFUELSThedirectemissionsoffossilfuelsaremainlycarbonemissionscausedbytheon-siteconsumptionoffossilfuels(coal,oil,naturalgasandtheirderivativefuels)byconstructionmachinery.Accordingtoavailableconstructioninventory,carbonemissionsoffossilfuelconsumptioncanbecalculatedusingthefollowingtwomethods:i)ifthetypesoffossilfuelsandthecorrespondingconsumptioncanbeobtained,Method1isrecommendedforcalculatingcarbonemissions(Equation(6.1),withrelativelyhighaccuracyofresults;ii)ifthedetailsoffossilfuelconsumptionarenotavailable,emissionscanbecalculatedaccordingtothenumberofmachineshifts(Method2,(Equation(6.2),thoughtheaccuracyoftheresultsofthismethodarelow.Method1:𝑛(6.1)𝐶𝐸𝑟𝑙=∑(𝑀𝑟𝑙,𝑖×𝐸𝐹𝑟𝑙,𝑖)𝑖Where:—Carbonemissionsoffossilfuel,kgCO2-eq𝐶𝐸𝑟𝑙—Totalamountofthefossilfueliconsumed,,kg,m3𝑀𝑟𝑙,𝑖Theemissionfactoroffossilfueli,,kgCO2-eq/kgorkgCO2-eq/m3.See𝐸𝐹𝑟𝑙,𝑖—𝑛AppendixB.1—Totalnumberoffossilfuelsused71Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorMethod2:𝑛(6.2)𝐶𝐸𝑟𝑙=∑(𝑇𝑖×𝑆𝑖×𝐸𝐹𝑟𝑙,𝑖)𝑖Where:𝐶𝐸𝑟𝑙—Carbonemissionsiffossilfuel,kgCO2-eq𝑇𝑖—Thenumberofshiftsofmachinei𝑆𝑖—Thefossilfuelconsumptionpershiftofmachine𝑖.SeeBuildingCarbonEmissionCalculationStandard(GB/T51366-2019)𝐸𝐹𝑟𝑙,𝑖Theemissionfactoroffossilfuelformachine𝑖,kgCO2-eq/kgorkgCO2-—eq/m3,seeAppendixB.1𝑛—Totalnumberofmachinetypesused6.3INDIRECTEMISSIONSFROMELECTRICITYCONSUMPTIONTheelectricalconsumptionintheassetreplacementanddemolitionstagealsocontributesasignificantportionofthetotalGHGemissions,andiscalculatedasshowninEquation(6.3).𝐶𝐸𝑑=𝐸𝑑×𝐸𝐹𝑑(6.3)Where:Carbonemissionsofelectricalconsumption,kgCO2-eqTotalconsumptionofelectricity,kW·h𝐶𝐸𝑑—Theemissionfactorspecificfortheimportedelectricity,kgCO2-eq/kW·h.SeeAppendixB.2𝐸𝑑—𝐸𝐹𝑑—6.4INDIRECTEMISSIONSOFTRANSPORTATIONThebuildingwasteproducedintheassetreplacementanddemolitionstagerequirestransportationfordisposalorrecyclingandreuse,whichwillgenerateacertainamountofGHGemissions.TheaccountingmethodcanrefertoEquation(6.4).𝑛,𝑙(6.4)𝐶𝐸𝑦𝑠=∑(𝑀𝑦𝑠,𝑖,𝑗×𝐿𝑦𝑠,𝑖,𝑗×𝐸𝐹𝑦𝑠,𝑗)𝑖,𝑗Where:—Carbonemissionoftransportationforwasteorotherservice,kgCO2-eq𝐶𝐸𝑦𝑠𝑀𝑦𝑠,𝑖,𝑗Thetotalamountofwastetransportedbythetransportationtypejinthe—activityi,t𝐿𝑦𝑠,𝑖,𝑗:—Thedistanceofwastetransportedbythetransportationjintheactivityi,,km𝐸𝐹𝑦𝑠,𝑗Theemissionfactoroftransportationj,,kgCO2-eq/(t·km),seeAppendix—B.4𝑛—Thenumberoftransportationactivities𝑙—Thenumberoftransportationsinoneactivity72Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAssetreplacementanddemolition6.5CARBONOFFSETVIAMATERIALRECOVERYThecarboncreditbywasterecyclingandreusecanbecalculatedbyEquation(6.5).𝑛(6.5)𝐶𝑆𝑐𝑙=∑(𝑀𝑐𝑙,𝑖×𝐸𝐹𝑐𝑙,𝑖)𝑖Where:Carboncreditofwasterecyclingandreuse,kgCO2-eq𝐶𝑆𝑐𝑙—Theindustrialproductequivalentoftherecoveredwastebytypei,kg,m3𝑀𝑐𝑙,𝑖—Emissionfactoroftheindustrialproductreplacedbyrecoveredwastei,,kgCO2-eq/m3orkgCO2-eq/t,seeAppendixB.3𝐸𝐹𝑐𝑙,𝑖—Thenumberofwastetypesrecovered𝑛—73Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter7Carbonreductionpathwaysinurbanwatersectors7.1OVERVIEWOnOctober24,2021,theStateCouncilofChinaissuedtheActionPlanforCarbonDioxidePeakingBefore2030(NDRCofChina,2021)tosteertowardspathwaysofreachingcarbonemissionpeakby2030.Thisplansetsouttenactionstoachievepeakcarbonemissionsthroughoutthewholeprocessesandeconomicandsocialdevelopment,andhighlightstheimportanceofreachingtargetsinanintegratedmanner.Asexplicitlystatedinthisplan,oneofthegoalsofattainingpeakcarbonemissionistheformationofalow-carbondevelopmentmodelforwholesociety.OnJune13,2022,theStateCouncilissuedanotherguidenamedImplementationPlanforSynergizingtheReductionofPollutionandCarbonEmission(TheStateCouncilofChina,2022).Thisplanclearlydefinesthecontributionofwastewaterresourceutilizationtocarbonreduction,encourageswastewatertreatmentplantstoactivelyimplementenergysavingandcleanenergyutilization,promotesthecarbonaccountingofurbanwastewatertreatmentandresourceutilization,optimizesthemanagementofenergyconsumption,andcarbonemissionofwastewatertreatmentfacilities.ForChina’surbanwatersector,waterconsumptionandwastewaterproductionwillcontinuetogrowasthepopulationgrowsandlivingstandardsimprove(Huangetal.,2023).Inaddition,theburdenofurbanstormwatersystemisbecomingheavierduetoincreasingextremerainfallevents(Maetal.,2022).Assuch,thecarbonintensityoftheurbanwatersectorshouldbereducedtooffsetthecontinuousincreaseofhandledwatertoachievepeakcarbonemissions.Inotherwords,carbonaccountingisnotthegoalandendpoint,butratherenhancingthesynergyofpollutionreductionandcarbonreductionofwatersectoris,topromotethesustainabledevelopment,toguidethedevelopmentandevaluationofcarbonreductionplan,toassistintheoptimizationoftechnologyselection,energysaving,andfinallycarbonreduction.AsdepictedinFigure7.1,carbonaccountinggoesthroughthewholeprocessofcarbonreductionactionsintheurbanwatersector.Carbonaccountingcanclarifycarbonemissionsourcesandcontributions,whichcaninturnguideandtargetcarbonreductionmorespecifically.Moreover,carbonaccountingcanhelpchooseoptimaltechnologiesbyclarifyingtheircarbonfootprint.75Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure7.1Schematicdiagramoftheinteractionbetweencarbonaccountingworkandcarbonemissionreductionactions.Fromtheperspectiveofthewholelifecycleoftheurbanwatersector,carbonemissionsareassociatedwithplanningandconstructionandoperationandmaintenance,aswellasassetreplacementanddemolition.Thus,thecarbonaccountingandreductionoftheurbanwatersectorshouldnotbelimitedtotheoperationandmaintenancestagebutitswholelifecycleoffromcradletograve(Seyedabadietal.,2023).Theplanningandconstructionanddemolitionprocessbelongstothegeneralconstructionindustry,whichisoneofthetraditionalhighcarbonemissionindustries.Thus,carbonemissionfromplanningandconstructionisreferredtoashiddencarbonandshouldbetakenintoconsiderationinthewatersector.Intermsofthecontributionofplanningandconstructiontototalcarbonemissionsofthewatersector,hiddencarboniscloselyrelatedtotheoperatinglifeofthestructure.AsshowninFigure7.2,whenthestructurelifeis20-30years,thecarbonemissionsfromplanningandconstructionaccountedforabout10%ofthetotalcarbonemissionsofthewatersupplysystemwhilethecontributionforwastewatersystemsaccountedforabout3%-5%(NEEP,2023).Intermstheofdemolitionstage,thepropermanagementandrecyclingofbuildingwasteisgenerallyabletooffsetthecarbonemissionsofdemolitionoperations.Overall,withinthelifecycleoftheurbanwatersector,theoperationandmaintenancephaseisthelargestcontributorofcarbonemissionsandshouldbethekeyfocalpointofcarbonemissionreduction–althoughthecarbonemissionofplanningandconstructionshouldalsonotbeunderestimated.76Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorFigure7.2CompositionofCarbonEmissionsfromChina’sUrbanWaterAffairsSystem(Relatedresearchisextremelylimited,andtheresultsvarywidely.ThisFigureisonlyforreference).Theoperationandmaintenancephaseoftheurbanwatersectoraccountsforabout6.1%oftheworld’stotalelectricityconsumption(TheWorldBank,2019).Withinthewatersector,thewatersupplysystemaccountsforabout42%oftotalelectricityconsumptionwhiletheseawaterdesalinationandreclaimedwatertreatmentaccountsforabout26%(Salas,2023).Inaddition,wastewaterandsludgetreatment,buildingplumbingsystem,andlong-distancewaterdeliverycontribute14%,13%,and5%,respectively(Salas,2023).IntermsofthecarbonemissionofthewatersectorinChina,informationisverylimitedandsomeoftheresultsavailablefromdifferentstudiesvarygreatly.Assuch,basedonChina’sUrbanandRuralConstructionStatisticalYearbook(MHURDofChina,2020)andUrbanDrainageStatisticalYearbook(CUWA,2018),theseGuidelinesfirstlycalculatestheenergyconsumptionandcompositionofChina’surbanwatersector.Theresultsshowthattheannualpowerconsumption(waterproductionandwatersupply)ofChina’swatersupplysystem(excludinglong-distancewatertransfer)isabout4.75×1010kWh/a,andwastewatertreatmentfacilities(includingreclaimedwaterplantsbutexcludingwastewaterdrainagesystem)consumesabout1.69×1010kWh/a(CUWA,2018).Intermsofstormwatermanagementsystems,electricityconsumptionstatisticsarelacking.Accordingtopreviousstudies,themajorcarbonemissionactivityofthewatersupplysystem,waterreclamationsystem,andstormwatersystemiselectricityconsumption.Bycontrast,wastewatermanagementsystemspresentsomedifferencesduetotheexistenceofbiologicalprocessesindrainagesystemsandwastewatertreatmentplants,andleadtoCH4andN2Oemissionwhicharedenotedasdirectemissions.Thispartofcarbonemissionsisaboutthreetimesthatofthepowerconsumptionbywastewatersystems.Byextrapolatingtothewholewatersector,thepercentagesofcarbonemissionsfromelectricityconsumptionofwatersupplysystems,electricityconsumptionofwastewatermanagementsystem,andbiologicalprocessesofwastewatermanagementsystemareabout30%,10%,and30%,respectively(Figure7.2).Thesumofthesethreepartsaccountsformorethan80%ofthetotalcarbonemissionsofthewholeurbanwatersector.Next,thecarbonemissionsofChina’swatersectorareestimatedroughly.Atypicalcarbonemissionintensityofthewatersectorisobtainedfromaliteraturereview(Huangetal.,2023;Xietal.,2023).TheactivitydataincludingthequantityofwaterconsumptionandwastewaterproductionofChinaisreferred77Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectortotheUrbanConstructionStatisticalYearbook(MHURDofChina,2020).AsdepictedinFigure7.3,thetotalcarbonemissionsofthewatersectorin2022wasabout114.88milliontCO2-eq,accountingfor0.82%ofthetotalcarbonemissionofChina.Also,wastewatermanagementsystemsarethelargestemissioncontributorofwatersector.Itseemsthateveniftheurbanwatersectorachievescarbonneutrality,itscontributiontothecarbonneutralityofsocietyasawholewillbeverylimited.However,waterasaproductiscloselyrelatedtootherindustries.Therefore,carbonreductioninthewatersectorcanbeofgreatbenefit,helpingotherindustriestoreducetheircarbonemissions.Inaddition,climatechangehasbroughtnewchallengestotheoperationandmanagementoftheurbanwatersector(Winchell,2021).Mostimportantly,theintroductionofcarbonneutralitytotheurbanwatersectorisalsoconducivetotheirownsustainableimprovementandoptimization,andstrengthensresilience.Therefore,theurbanwatersectorshouldtaketheinitiativeinincorporatingcarbonreductionintooperations,development,evaluation,etc.Fromtheperspectiveoftheimplementationrouteofcarbonreductioninurbanwatersectors,alignmentwiththenational30and60dualcarbongoalscanbeconsideredasthemostbasictimepoint.Toprovideaclearpictureofthecarbonreductiontargetsthatneedtobeachievedateachstageoftheurbanwatersector,theseGuidelineshavesimulatedthetrendsintotalcarbonemissionsofthewatersectorinChinaunderdifferentscenariosbasedonliteraturedata(Figure7.3).Giventhecontinuedriseinurbanizationlevels,populationgrowth,andinfrastructurecoverage,theamountofwaterhandledbywatersectorsisboundtoincrease.Theexpectationsforimprovedwaterqualityandstringentwastewaterdischargestandardswillalsoneedmoreelectricityandmaterialinput.Therefore,basedonthebaselinevalueofcarbonemissionsin2022,ifthewaterindustrydoesnotactivelyadoptcarbonreductionmeasures,itstotalcarbonemissionswillreach198.53milliontCO2-eqby2060,whichisnearlytwicethatofthecurrentlevelofcarbonemissions.Admittedly,carbonreductionwillnothappenovernight.Ifcarbonpeakingistobeachievedby2030,urbanwatersectorwillneedtostartreducingcarbonemissionsimmediately.Byreducingthecarbonintensityofthewatersectorinordertooffsettheincreaseincarbonemissionscausedbyincreasedwateruse.Itcanbeestimatedthattoachievecarbonneutralitytargetby2060,continuedandincreasedreductionswillberequiredbetween2030and2060tooffsettheremaining128.9MtCO2-eqofcarbonemissions(Figure7.3).FromthecompositionofcarbonemissionsinChina’surbanwatersectors,itisclearthatthefocusofcarbonreductionshouldbeonelectricityconsumptioninwatersupplysystems,stormwatermanagementsystems(liftpumps),wastewatermanagementsystems(liftpumpsandaerationpumps),andbiologicalprocessesproducingCH4andN2Oinwastewatermanagementsystems(septictanks,wastewatercollectionnetworks,andwastewatertreatmentplants)(Sunetal.,2018;Shortetal.,2017).Inordertoreducecarbonemissionfromelectricityconsumption,itisnecessarytorelyonpowercompaniestogreentheirelectricitygeneration.However,urbanwatersectorsshouldalsoworkhardtoreduceelectricaluseasmuchaspossibletooffsetthecontinuedincreaseinwaterandwastewatervolumes.Thispathwaywillnotonlyachievecarbonreductionbutalsoreduceoperatingcostsinthewatersector.Thisisparticularlyimportantforstormwatermanagementsystemsasforceddrainagesystemsrequirepumpingstationsandresultantelectricityconsumption.Thus,optimizingthedesignofstormwaterrunoffandreducingdeeptunnelingarekeytoreducingtheelectricityconsumptionofstormwatersystems.78Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorFigure7.3CarbonemissionreductionintensityandroadmapofChina’surbanwateraffairssystem(Δindicatesthetotalcarbonemissionsofthewastewatermanagementsysteminsomeliterature.Datasource:MinistryofHousingandUrban-RuralDevelopmentofthePeople’sRepublicofChina.Somedataand/orassumptionsadoptedasfollows:i)totalurbanwatersupplyof89.38billiontandwastewatertreatedof69.36billiontin2020,ii)wastewatercompositionofCOD=350mg/LandNH+4-N=50mg/L,iii)anetpopulationgrowthrateof1.45%annually,iv)theenergyintensityofwatersupplysystemis0.53kWh/m3andthewastewatertreatmentplantsis0.24kWh/m3,whilesludgelandfillingisthedisposalmethod,v)fossilcarboncontentinwastewateris10%,vi)emissionfactorsofCH4andN2Oare3.6kgCO2/tBOD5and10.6kgN2O-N/tN.).Basedontheprinciplesofcarbonreduction,carbonreductiontechnologiescanbeinternationallyclassifiedintothreecategories–namely,carbonreduction,renewableenergy,andcarbonsinks(Lietal.,2023).Carbonreductionreferstothereductionoffossilfuelconsumptionordirectcarbonemissionsthroughtheoptimizationorinnovationofexistingprocessesandtechnologies.Renewableenergyreferstothereplacementoffossilfuelswithcleanenergytoachieveemissionreductions.Carbonsinksreferstotheabsorptionandfixationofgreenhousegasesintheatmospherethroughtreeplantingandothermeans.Specifically,forurbanwatersectors,thecomplexcompositionofcarbonemissionsandcarbonemissionactivitiesdictatethattherearemanycorrespondingtechnologiesthatcanbeusedtoreducecarbonemissions.TheseGuidelineshavefurthersubdividedthesethreecategoriesintofivetypesofactionstrategies.AsshowninFigure7.4.•Sourcecontrol:targetingthefundamentalsourceofcarbonemissionsbyreducingtheamountofwaterand/orpollutantsthattheurbanwatersectorneedstohandle,reducingenergyandmaterialconsumptionanddirectgreenhousegasproduction;•Processoptimization:optimizingequipment,reactor,andoperationalcontrolstrategiesinurbanwatersectorstoimproveoperationalefficiency,reduceenergyandmaterialconsumptionintensity,andcontrolenvironmentalconditionsthatleadtodirectgreenhousegasgeneration;79Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector•Technologyupgrading:developingnewlow-energy,low-carbon-emissionprocessesandsystemstoreplacehigh-energy,high-carbon-emissiontraditionalprocessesandsystems;•Low-carbonenergy:tappingandrecoveringtheenergycontainedwithinurbanwatersectors,supplementedusingothercleanenergysources(wind,solar,organicmatter,wasteheat,etc.)toreducefossilfuelconsumption;•CO2sequestration:sequestratingCO2fromtheatmospherethroughmeasuressuchasafforestationandrevegetation.Figure7.4Actionplanroadmapforcarbonemissionreductioninurbanwatersectors.AssummarizedinFigure7.4,sourcecontrol,processoptimizationandtechnologyupgradingactionstrategiesbelongtothecarbonreductioncategory,whilelowcarbonenergystrategiesbelongtotherenewableenergycategory.Generally,carbonreductionstrategiesarebasedonexistingprocesstechnologies,arequicktoimplementandaresmallinscaleintermsofengineeringandinvestment,andshouldbethefirstchoicefordevelopingcarbonreductionplansforurbanwatersectors.However,itisnotpossibletoachievecarbonneutralitybyrelyingoncarbonreductionstrategiesalone,andlow-carbonenergyisthewaytogo.Thelow-carbonenergyactionstrategyfocusesontherecoveryofenergywithinthewatersector(e.g.chemicalandthermalenergy)(Meerburg,etal.,2015;CipollaandMaglionico,2014).Asenergyrecoveryfacilitiesinwatersectors(e.g.,anaerobicdigestion)arecurrentlynotcommoninChina,theimplementationofthisstrategywillinevitablyinvolveahugeinvestment.However,the80Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorcarbonreductionpotentialishuge,asnotonlywillthewatersystemitselfbecomecarbonneutral,butitisalsoexpectedtoexportcleanenergytosocietyand/ortobeusedforcarbontrading(Haoetal.,2019a).TheCO2sequestrationstrategyfocusesonplantsinkenhancementandcarbonsequestrationbygreenfacilities.Stormwatermanagementsystemsinvolveawiderangeofspacessuchasgreenroofs,permeablepavements,bioretentionareas,andvegetatedfilterstrips,andarenaturallycoupledwithurbanecosystems(Pelorossoetal.,2017).Greeninfrastructuresarewidelyadoptedintheplanningandconstructionofstormwatermanagementsystemsandhavemultiplebenefits,enhancingstormwaterrunoffcontrolandcarbonsequestrationinecosystems.Moreover,theirlowimplementationcostcanbewidelypromotedinurbanwatersectors.Ofcourse,therealizationofcarbonneutralityinurbanwatersectorsdoesnotdependsolelyontechnologicalprogress,butrequiresahighlevelofforesightandunifiedplanningfromthemanagement,formingacarbonreductionapproachofpolicytraction,normativeconstraints,andtechnologicalimpetus.Thischapterfirstlyanalysesthefocusofcarbonemissionreductionandthecollaborationbetweendifferentsub-systemsfromtheurbanwatersectorsasawhole,andthenfurtherrefinesandsummarizesthefivetypesofactionstrategies.Basedonthecharacteristicsofcarbonemissionsatdifferentstagesofthelifecycle,theemissionactivitiesofplanningandconstructionandassetreplacementanddemolitionareanalyzed,withanemphasisontheemissionreductionpathwaysintheoperationandmaintenancephaseofwatersectors.Thetechnicalchoices,actionstrategies,andplanningimplementationcateringforcarbonemissionreductionofsub-systemareanalyzedseparately,withaviewtoprovidingreferenceforthedevelopmentofcarbonemissionreductionplansforurbanwatersectorsinChina.Fromtheperspectiveofcarbonreduction,thewaterreclamationsystemisveryclosetothewatersupplysystem.Therefore,thetwosub-systemsareanalyzedinthesamesection.7.2SYNERGYOFSUBSYSTEMS’CARBONEMISSIONREDUCTIONINURBANWATERSECTORSAlthoughthewatersupplysystem,wastewatermanagementsystem,waterreclamationsystemandstormwatersystemhavedifferentoperatingentities,asanintegralpartoftheurbanwatersector,thesedifferentsubsystemsareinterlinkedandaffecteachother.Therefore,whenformulatingcarbonreductionplansforurbanwatersectors,fullconsiderationshouldbegiventothesynergybetweenthedifferentsubsystems.Inotherwords,thecarbonreductionstrategiesofonesubsystemshouldbelinkedtotheothersubsystems.Becauseofthis,theinterlinkandassociatedactionstrategiesaresummarizedinTable7.1.Waterauthoritiesorindustryassociationsshouldstrengthenthelinksbetweendifferentsubsystemoperatorsandprioritizethepromotionofsuchactionstrategiesinordertoachievemoreeffectivecarbonreductionwithlesseffort.81Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable7.1Summaryofsynergiesofactionstrategiesamongvarioussubsystemsinurbanwatersectorforcarbonreduction.WatersupplysystemWastewatermanagementsystemWaterreclamationsystemStormwatersystemWaterconservation,ortieredTheimplementationofwaterpricingfordifferentvolumesandareasofwateruse,willconservationcampaignsandWaterconservation,ortieredpricingforpromotethereuseofstormwater,reducetheloadonenforceablemeteringwillnotonlydifferentvolumesandareasofwaterstormwaterdrainagesystems,andachievecarbonreductionWatersupplyreducetheloadonthewatersupplyuse,willnotonlysavewater,butalso\systemsystem,butalsoreducetheloadonprovideacostincentiveforsomeareaswastewatercollectionandtreatmenttoadoptrecycledwaterandreducefacilitiessoastoachievecarboncarbonemissions.reductionWhentheeffluentfromawastewatertreatmentplantisdischargedupstreamofthewatersource,strictdischargestandardscanreducewaterWhentheeffluentofwastewaterWastewaterpurificationcostsbutincreasetreatmentplantissubsequentlyreused,managementenergyandchemicalconsumptionthetreatmentprocessesshouldbesystemforwastewatertreatment.Thedesignedinaccordancewiththereuseadoptionofaseparatedrainagepurposetoavoidover-processingandsystemcanreducetheadverseunnecessaryenergyinput.impactofCSOonwatersources,reducewaterpurificationcost,andachievecarbonemissions.Continued82Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorWatersupplysystemWastewatermanagementsystemWaterreclamationsystemStormwatersystem\Intownswherelocalwaterresourcesarescarce,theconstructionofrecycledwatersystemsandthereuseThewastewatertreatmentprocessesWaterofeffluentshouldbepromotedinshouldbedesignedinaccordancereclamationsystemaccordancewithlocalconditions,withthereusepurposetoavoidover-Stormwaterwhichcansaveenergyconsumptionprocessingandunnecessaryenergysysteminwatersupplysystemsoverlonginput.distancesandachievecarbonemissionreduction.SeparatedrainagesystemsorstormwatercontrolfacilitiesareadoptedtoreducetheamountofStormwaterreusecanreducethestormwaterenteringthewastewaterloadonthewatersupplysystemand\drainagesystem,reducetheloadofachievecarbonemissionreductionwastewaterconveyanceandtreatment,andachievecarbonemissionreduction83Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector7.3PLANNINGANDCONSTRUCTIONANDASSETREPLACEMENTANDDEMOLITION7.3.1OverviewFromthecarbonemissionactivitiesofthewatersector,wecantellthattheselectionofwatersourcesinthewatersupplysystemwillaffectthepowerconsumptionofwaterintakefacilities.Thelocationofwatertreatmentplants,andtheirdistancefromwateruserswillaffectthepowerconsumptionofthewatersupplysystem.Inthewastewatermanagementsystem,thegravitydrainagepipenetworkandthedistributionofwastewatertreatmentplantsdeterminesthedepthatwhichpipesareburiedwhich,inturn,affectsthenumberofliftpumpsandliftingheight,aswellastheassociatedpowerconsumption.Inaddition,thedifferentwastewatertreatmentprocessesandtherequiredeffluentdischargestandardwillalsoleadtodifferencesincarbonemissions.Inastormwatermanagementsystem,theadoptionofstormwatercontrolfacilitiesordrainagenetworkwillresultinadifferenceincarbonemissionsaswell.Fromtheperspectiveofthelifecycleofthewatersectors,theaboveaspectsaredeterminedintheplanninganddesignstage,andarenoteasytochangeandoptimizeafterconstructionandoperationbegins.Therefore,theimpactofplanninganddesignonthecarbonemissionsofthewatersectorsisdecisive,astheresultscannotbecompletelyreversedthroughoptimizationofoperationandmaintenance(Zhouetal.,2023;Sunetal.,2023).Inaddition,althoughconstructionisnotdirectlycontrolledbythewatersectors,carbonemissionsareincludedintheaccountingboundary.Assuch,planningandconstruction,asthebeginningofthelifecycleofthewatersector,isalsotheprimarypointforimplementingcarbonreduction.Ingeneral,97%ofcarbonemissionsintheplanningandconstructionstagecomefromtheuseofvariousbuildingmaterialssuchassteelandconcrete(Hongetal.,2015).Therefore,thecarbonemissionsintheconstructionstagecanbereducedbysavingbuildingmaterialconsumptionwhilemaintainingbuildingstrength,orusinglow-carbonbuildingmaterials.Prefabricatedcomponentsareusuallyuniformlydesignedandproduced,andneedlessenergyandrawmaterialsintheirmanufacture.Greenmaterialsandrecycledmaterialsarehighlyrecommendedforreducingcarbonemissionsintheconstructionstage(Zhaoetal.,2023).Duringbuildingdemolition,carbonemissionsfromthedemolitionoperationaccountforapproximately70%oftotalemissions,withtherestcomingfromthetransportationanddisposalofdemolitionwaste(Wangetal.,2018).Throughtheprocessofsorting,shreddingandscreeningofwaste,recyclingandreusecanbeachieved,whichisapathwaytooffsettingacertainamountofcarbonemissions.84Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorTable7.2Summaryofactionstrategiesforcarbonreductioninplanningandconstructionandassetreplacementanddemolition.StageStrategyAuthorityTechnicalrecommendationImplementationnotesTakingwastewatertreatmentplantsasanexample,wecanseeSelectionofwatersources;spatiallocationandthatcarbonemissionintensitycausedbyelectricityconsumptiondesigncapacityofwatertreatmentplants;pressureisassociatedwiththedesigncapacity.Generally,thelargertheRegimeandzone-basedwaterdistribution;regimeofscale,thelowertheelectricityconsumptionintensityis.spatiallayoutofwastewaterdrainagesystem;treatmentcapacity,Moreover,differentprocessesalsoleadtodifferentlevelsofurbanwatertechnologyselection,andeffluentdischargecarbonemissionintensity.Forexample,theSBRprocessissectorstandardsofwastewatertreatmentplants;sludgesuitableforsmallwastewatertreatmentplantstoobtainalowdisposalpathway;stormwatermanagementelectricityconsumptionintensity,whiletheoxidationditchandsystems,etc.AAOprocessesaremoresuitableforlarge-scalewastewatertreatmentplants.PlanningandHigh-efficiencyPlanningChoosemechanicalequipmentwithhighenergyReasonableandappropriateselectionandoperationofconstructionequipmentanddesignefficiency,longservicelife,andlowfailureratemechanicalequipmentcanreduceenergyconsumptionanddepartmentcarbonemissionsinfutureoperations,andpreventadditionalemissionscausedbyfrequentmaintenance.AppropriatepressuremanagementcanavoidpressurewastePressureThewaterdistributionnetworkisseparatedintowhereby,throughelectricityconsumptionandresultantcarbonmanagementofpressurezoneswhichare,inturn,separatedbyemission,waterleakagecanbedecreased.Thekeytowatermeansofpressurereducingstations,gatevalvesandimplementationpressuremanagementistoobtainascientificdistributioncheckvalvespressurezone.Thisshowsthatpressuremanagementcanreducesystemleakagelossby6.2m3/km,equivalenttoreducing68tCO2-eq/kmemissions.OptimizationofConsideringtheconstructionofwastewaterTheprocessofadjustingandoptimizingdrainagesystemiswastewaterdrainageandtreatmentplantsinanintegratedcomplexandrequiresconsiderationoffactorssuchasurbanContinued85Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorStageStrategyAuthorityTechnicalrecommendationImplementationnotesdrainagesystemmanneraccordingtolocalconditions,reducingtheconstructionandthedegreeofsophisticationofsupportingamountofwastewaterthatdoesnothavetoenterfacilities.Ifaseparatedrainagesystemisadopted,initialNewdrainagethetreatmentplantasfaraspossible,optimizingthestormwaterrunoffpollutionshouldbeconsideredtoavoidsystemdesignofdrainagesystemsandreducingthepollutingthereceivingwaterbodies.Overall,optimizationoftheformationofalong-termanaerobicenvironmentindrainagesystemrequiresalongperiodofexplorationandAdoptingthedrainagepipes,e.g.byadoptingaseparateexperienceaccumulation,aswellascorrespondingtop-levelstormwaterdrainagesystem,maintainingpipestoreducedesignandpolicyguidancetreatmentplantsinfiltrationofexternalwater,optimizingthesettinganddeepofseptictanksTheinnovationandapplicationofthenewdrainagesystemtunnelsforrequirestop-leveldesignandpolicyguidance.ThevacuumcautionInnovationindrainagesystemswithlowcarbondrainagesystemusesnegativepressuresuction,andinvestmentAdoptingfootprintsolutions,e.g.,vacuumdrainagesystemsandoperationenergyconsumptionanalysisshouldbecarriedoutprefabricatedtoreducetheresidencetimeofwastewaterinthetoavoidthetransferofcarbonemissions.Typically,vacuumpipes,reducingtheformationofananaerobicdrainagesystemscanreducetheconsumptionofflushingwaterenvironmentandgreenhousegasgeneration.by40%.Large-scalecentralizedgrayfacilitiesofstormwaterReducingenergyinputtreatmentplantsanddeeptunnelprojectswillgeneratealotofenergyconsumptionandcarbonPrefabricatedcomponentshaveafixedproductionprocess,emissionsduringconstructionandoperation.Greenwhichismoreefficientandsavesmaterialandenergystormwatermanagementfacilitiescouldbealternatives.ContinuedUseofuniformlydesignedandproducedprefabricatedcomponentsforassemblyconstruction86Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorStageStrategyAuthorityTechnicalrecommendationImplementationnotescomponentsandmethodstoreducetheamountofon-siteconsumptioninproduction;theassemblyprocesshasstandardAssetprefabricatedconstructionoperatingmethods,whichimprovesconstructionefficiencyandreplacementconstructiongenerallyreducescarbonemissionsby3-7kgCO2-eq/m2.andConstructionUseofconstructionmaterialswithrenewableorHowever,inpractice,therearealsospatialconstraintsondemolitionGreenbuildingdepartmentrecyclableproperties,andlocalbuildingmaterialsfactorysites,whichmayrequirelongertransportdistances.materialstoreducetransportemissionsRenewablebuildingmaterialssuchaswood,andrecyclablebuildingmaterialssuchasrecycledaggregatesaregreenbuildingScreen,processConstructionConstructionwastecannotbeburied,butshouldbematerialswithlowcarbonemissions.Fornon-load-bearingandrecycledepartmentproperlyscreenedandprocessedintorecycledstructuresinbuildings,theuseofgreenbuildingmaterialstoconstructionbuildingmaterialsaccordingtoactualconditionstoreplacetraditionalhigh-carbon-emittingmaterialscanreducethewasteoffsetcarbonemissionscarbonemissionsofbuildingmaterials.Long-lifebuildingmaterialsshouldbeconsidered.Therecyclingofconstructionwastecangeneratemorecarbonoffsets.Ifitisproperlytreated,itcangenerallycompletelyoffsetthecarbonemissionsofassetreplacementanddemolition87Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector7.3.2Carbonreductionpathways7.3.2.1PrefabricatedbuildingAprefabricatedbuildingisabuildingthatismanufacturedandconstructedusingprefabrication.Itconsistsoffactory-madecomponentsorunitsthataretransportedandassembledon-sitetoformthecompletebuildingwhilecast-in-placebuildingsarepouredandconstructedontheconstructionsite.Intermsofcarbonemissions,themaincontributorsinprefabricatedbuildingarethefactory-madestageandtransportationwhicharehigherthancast-in-placebuilding.However,lessenergyinputisneededintheconstructionstageforprefabricatedbuildingcomparedtocast-in-placebuilding,whichleadstolesscarbonemissionsoverall.Inshort,prefabricatedbuildingcanreducecarbonemissionby3-7kgCO2-eq/m2comparedwithcast-in-placebuilding(Caietal.,2023).Inaddition,thereislessconstructionwaste,noise,anddustpollutiongeneratedduringtheconstructionofprefabricatedbuildings,thusmakingthemagreenerandmoreenvironmentallyfriendlyoption.CarbonemissionsfromthelivesofconstructionworkersareunavoidableandarenotincludedinthecarbonaccountingaccordingtotheaccountingprinciplesproposedinthisGuidelines.However,theuseofmanypeopleinsteadofmachinerycanleadtoasignificantreductioninworkefficiency,longerconstructionperiods,andasurgeininvestmentcosts.Therefore,itisimportanttochoosethebestresultsforemployingconstructionmanpowerbasedontheactualsituationandweshouldnotabandonmachineryforfearofcarbonemissions.7.3.2.2OptimizationoflightingandventilationdesignLightandventilationisoneofthekeydesignpriorities,notonlyinrelationtotheenergyconsumptionandcarbonemissionsoftheequipmentinoperation,butalsoinrelationtothehealthofthepeoplewhoworkandlivethere.Forwatersectors,therearesomefacilitiesplacedindoorswherethelightandventilationssystemshouldbepaidattentionto,soastoavoidtoomuchelectricityconsumption.Forexample,doorsandwindowsinthebuildingshouldbeappropriatelyexpandedtoenhancethenaturallightingcapacityofthebuilding,thusreducingtheenergyconsumptionandcarbonemissions.Thedirectionofthebuildingdoorsandwindowsshouldbereasonablydesignedtoleveragethenaturalwindflowforindoorventilation,whichcouldalsoreduceindoorodorandheatdissipation,thuscarbonemission.7.3.2.3OptimizationofequipmentselectionThenormaloperationofwatersectorscannotbeachievedwithoutalargeamountofmechanicalequipment,includingpumps,agitators,aerationequipment,etc.(Aghabalaeietal.,2023;Guetal.,2023).Theelectricityconsumptionthismechanicalequipmentisacarbonemissionactivitythatcannotbeignoredinwatersystems.Improvingtheefficiencyofmachineryandequipment,andsubsequentlyreducingelectricityconsumption,isthemainroutetoachievingareductionincarbonemissions.Forexample,theoptimumenergyefficiencyofapumpshouldkeepitoperatinginthehighefficiency,i.e.thewatervolumeshouldbekeptasclosetothedesignvolumeaspossible.However,watervolumesinwatersystemsoftenfluctuatewidely,leadingtoincreasedelectricityconsumption.Inthisregard,variablefrequencypumpscandynamicallyadjustwithfluctuationsinwatervolumeandcanalwaysbekeptoperatinginthehighefficiencyzone,ensuringthelowestcarbonfootprintpossible.Inaddition,aerationequipmentinwastewatertreatmentplantsisoneofthemainelectricityconsumingactivities,whichisattributedtotheloweroxygenationefficiencyoftheaerationequipment.This,inturn,canbeimprovedbyareasonablechoiceofaerationunitstoreduceelectricityconsumption.Inaddition,thechoiceof88Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectormachineryandequipmentshouldtakefullaccountoftherealitiesofthesituation.Foreffluentswithahighgritcontent,screensandtheircleaningequipmentthatareeasytoclearandnoteasilyblockedshouldbeselected.Equipmentwithalong-lifecycleshouldbeselectedinordertoavoidcarbonemissioncausedbyfrequentreplacementofequipment.7.3.2.4PressuremanagementofwaterdistributionInwaterdistributionsystems,pumpsaregenerallyselectedinaccordancewiththehighesthourlyflowrate,andthereforedeviatefromtheoptimumratedworkingconditionsmostofthetime.Inpractice,pressurecontrolisoftenimplementedbyreducingthevalve,whichresultsinwastedenergyandreducesitsservicelife.Inaddition,forsomehigh-risebuildings,secondarypressurizationisneeded,whichcannotleveragethepressurethewaterdistributionandresultsinpressurewaste.Waterleakageduetoexcessivepressureinthedistributionnetworkisalsoachallenge.Oneofthesolutionsforpressuremanagementistodividetheserviceareaintoseveralpressure-specificzoneswhichhavetheirowndistributionsystemwithdifferentdistributionpressures.Onestudyindicatedthata5.6mheadreductionintheinletpressureofBeijing’swaterdistributionnetworkcouldreduceleakageby6.2m3perkmofpipe,equivalenttoa68tCO2-eq/kmreductioninemissions.Itcanbeseenthatoptimizingpumpingconditionsorpressurezone-baseddistributioncanhelptosavewaterandreduceelectricityconsumptionsimultaneously.7.3.2.5DrainagesystemupgradeConventionalsewerscollectandconveywastewatertothewastewatertreatmentplantbygravityflow.Consideringtheamountofconstructionandthedifficultyofsubsequentmaintenance,sewersgenerallycontrolslopeandburialdepth.Inconventionalgravitydrainagesystems,theflowrateofwastewaterisslow.Forlargerurbandrainagesystems,wastewateratthebeginningtakes1to2daystogettothetreatmentplant.Suchalongresidencetimecanleadtoananaerobicenvironmentinthepipes,whichinturnleadstotheproductionandemissionoflargeamountsofgreenhousegases.Upgradingandoptimizingthedrainagesystemandimprovingtheenvironmentinsidethepipesisthereforeaneffectivemeansofreducinggreenhousegasproduction.Inthisregard,vacuumdrainagesystemsoffersignificantadvantages(Islam,2017;Miszta-Kruk,2016).Undernegativevacuumpressure,thewastewatercanbeliftedverticallyandtransportedtothetrunksewerortoawastewatertreatmentplant.Theshallowdepthofthevacuumdrainagesystem,themoreflexiblearrangementofthepipes,andthefasterflowrateofthewastewatermakeitlesspronetoblockagesandleaks,whichcangreatlyreducetheproductionofgreenhousegasesinthepipes.Again,theadoptionofseparatedrainagesystemscanpreventstormwaterandsewagefrommixing,avoidingpumpingstationsinthesewertopumpstormwater,reducingtheamountofwaterenteringthetreatmentplant,toachievethepurposeofreducingtheenergyconsumptionofpumpingstationsandtreatmentplants.Atthesametime,itcanalsopreventCSOpollution.7.3.2.6OptimizingthesettingofseptictanksaccordingtolocalconditionsBeforetheadoptionofcentralizedwastewatertreatmentsystems,septictanksservedasasimple,decentralizedwastewatertreatmentdevicethatdegradedorganicmatterandhadalimitedroleinwaterenvironmentalprotection.However,withcentralizedtreatmentbecomingprevalent,thedisadvantagesandhiddendangersofseptictanksarebecomingincreasinglyapparent.Firstly,septictanksaresourcesofhighcarbonemissions.InChina,thetotalannualCH4emissionfromseptictanksisashighas3×10789Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectortCO2-eq/a,whichisequivalenttothedirectcarbonemissionsfromwastewatertreatmentplants.Inaddition,septictankscanremovepart(30%)oftheCODresultingininsufficientcarbonsourcesforbiologicalnutrientremovalinwastewatertreatmentplants.Moreover,septictanksoccupyundergroundspaceandposeasafetyhazardbecauseoftheCH4accumulation.andover95%ofseptictanksarelikelytoleakafter1-2yearsofuse,notonlypollutinggroundwaterandcorrodingpipes,butalsosofteningthefoundationsofbuildings(Somlaietal.,2019;Withersetal.,2011).ItisworthnotingthatsomecitiesinChinahavestartedtoplanfortheeliminationofseptictanks.7.3.2.7CarefullyconsiderdeeptunnelprojectsAccordingtothedifferentobjectivesofstormwatercontrol,deeptunnelsincludevolumecontrol,stormwaterrunoffstorage,CSOstorage,stormwatertransfer,etc.Taketheanalysisofthecombinedflowsystemoverflowcontroltargetofthestoragetunnelasanexample:whenitrainsstormwaterisstoredinthedeeptunnel;andthen,afterwards,therainisliftedtotheshallowpipedrainagesystemthroughthetail-endpumpingstation,reducingthenumberoftimesthegatesareopenedinthewatershed,whichcanreducepollutionofthecombinedflowsewageandinitialstormwaterinthenearbywatershedduringtherainyseason,aswellasreducingtheappearanceofblacksmellywaterbodiesinthewatershedandimprovingthequalityofthewaterenvironmentinthewatershed,thusfurtherreducingcarbonemissionsgeneratedbyfossilenergyconsumption(Luoetal.,2021).However,thedeeptunnelprojectisalargeproject,anditsconstructionboostscarbonemissionsbymorethan50%comparedtoshallowsurfacepipelinesystems.Moreover,deeptunnelsrequirethedeploymentofsewageliftpumpingstations,whichincreasetheirenergyconsumptionbyaround10.40kWh/103m3.Deeptunnelsaregenerallylongindistanceandpronetosiltationinthetunnels,aswellasgeneratingsignificantcarbonemissionsintermsofoperationandmaintenance,soothergreenstormwaterfacilitiesshouldbeusedinthestormwatersysteminsteadwherepossible.7.3.3CarbonreplacementpathwaysAttheendofthelifecycleofbuildingsandstructuresinwatersectors,alargequantityofconstructionwastewillbeproducedafterdemolition.Insteadoflandfillingthewaste,recyclingandreusingitishighlyrecommendedasasustainablesolutionthroughthereasonableprocessingThisapproachcouldextendthelifecycleofmaterialsandproducecarboncredit.7.4WATERSUPPLYANDWATERRECLAMATIONSYSTEMS7.4.1OverviewBasedonthecompositionofcarbonemissionsofthewatersupplysystem,themaincontributorintheoperationandmaintenancestageiselectricityconsumption.Othersourcesincludechemicaland/orvariousmaterialsinput.Alltheseemissionactivitiesareclassifiedasindirectemission.Specifically,nearly100%oftheGHGemissionsinthelong-distancewatertransmissionfacilities,waterintakefacilities,andwaterdistributionsystemcomefromelectricityconsumptionofpumps.Intermsofwatertreatmentplantsandseawaterdesalinationplants,electricityconsumptionalsoaccountedfor95%,82%,and98%GHGemission(Tanetal.,2023;Maetal.,2022).Therefore,thekeytoformulatingcarbonemissionreductionplansforwatersupplysystemsistoimprovemanagementlevelsandoptimizetreatmenttechnologiestoreduceelectricityconsumption.AseriesofavailableemissionreductionpathwaysandsolutionsforwatersupplysystemsaresummarizedinFigure7.5andTable7.2.90Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorIntheaspectofsourcecontrol,measuressuchaswaterconservationbyusers,strengtheningwaterconsumptionmeasurement,gradientpricing,andwatersourceprotectioncanallreducewaterdemandandtherebytheworkloadingandcarbonemissionsofwaterintakefacilities,waterdistributionnetwork,andwatertreatment.Infact,waterreclamationsystemcanreducetheinputofexternalwater,whichisprobablyachievedbylong-distancewaterdeliveryandwaterintakefacilities.Thus,thereuseofwastewaterforcropirrigation,greenareawateringortoiletflushingcoulddecreaseelectricityconsumption.Intermsofprocessoptimization,watersupplysystemoperatorscanalsotakevarioustechnicalmeasurestoreducecarbonemissions,mainlyfocusingonimprovingtheoperationalefficiencyofpumpsandwateruseefficiency,includingtheapplicationoftechnologiessuchasnetworkleakagedetection,variablefrequencyspeedregulatingpumpsandfilterbackwashoptimization.Regardingtechnologyupgrading,newwatersupplysystemsandefficienttreatmenttechnologiesshouldbeactivelydeveloped,suchaspressuremanagementmodelsandlow-energyseawaterdesalinationwhichcansignificantlyreduceenergyconsumptionandcarbonemissions.Fromtheperspectiveoflow-carbonenergy,thewatersupplysystemcanalsoproducerenewableenergy,includingthermalenergyextractionandpotentialelectricitygeneration.However,itshouldbenotedthattheimplementationofenergyrecoveryfromwatersupplysystemsshouldavoidaffectingthewaterqualityandwaterpressuredesignedforusers.ThespecificactionstrategiesaresummarizedinTable7.3.Figure7.5Carbonreductionroadmapforwatersupplysystem.91Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable7.3Summaryofactionstrategiesforcarbonemissionreductioninoperationandmaintenanceofwatersupplysystem.TypeStrategyAuthorityTechnicalrecommendationImplementationnotesThecostofthesestrategiesislowbuteffectiveSourceCompulsorywaterManagementWatermeteringshouldbepromotedtostrengthensupervisionandlong-termwater-savingadvocacyaremetering/tieredwatermonitoring.Waterutilizationefficiencyshouldnecessary.Ithasbeenshownthatmandatorywaterpricing/water-bebenchmarkedandformulatedforvariousbuildingsmeteringcanreducewaterconsumptionby6Lperpersonsavingadvocacytoenhancewater-savingalongwithgradientpricingperday(refertotheNationalMatureandApplicableschemesandadvocacy.Water-savingTechnologyPromotionCatalogofthecontroldepartmentMinistryofWaterResources)WatersourceByprotectingthewatersourceandreducingtheinputWatersourceprotectionisasystematicprojectinvolvingprotectionofpollutants,thepollutantremovalloadingofthemulti-sectoraljointactions,andwiththeincreaseofwatertreatmentplantcanbereduced,therebyreducingclimatechangeandextremeweather,protectionwilltheconsumptionofelectricityorchemicals,andbecomemorechallengingachievingcarbonemissionreductionIthasbeenshownthatcomparedwithtraditionalwaterPumpoptimizationAdoptionofVFDpumpspumps,VFDpumpscanreduceenergyconsumptionandcarbonemissionsbyabout50%ProcessWaterleakageOperationByinstallingsensorsatspecificsitesofthepipe,theWaterleakagedetectionhasbeenpracticedmoreandoptimizationdetectiondepartmentinformationofflowrate,pressure,andotherindicatorsmore,andithasbeendemonstratedthatabout40%ofofthepipenetworkcanbecollectedandleveragedtowaterleakageinthepipenetworkcanbereducedquicklylocateabnormalpipesectionsWatertreatmentInwatertreatmentplantsandseawaterdesalinationTheadjustmentandoptimizationoftheprocesshasalotprocessplants,agreatdealofworkcanbedonetoreducetodowiththequalityofthetreatedwater–thatis,theoptimizationelectricityconsumptionandcarbonemission,suchasoptimizationdependsonthefeedbackofreal-timeoptimizationofbackwashingfrequencyandincreasinginformationmembranepretreatmentprocessesTechnologyNewSeawaterDesignandChoosenewequipmentwithhigherefficiencyandlessApplicabletowatersupplysystemsincoastalcitiesupgradingDesalinationplanningenergyconsumptionSystemdepartmentContinued92Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorTypeStrategyAuthorityTechnicalrecommendationImplementationnotesMicroturbinesforTherecoveryofpotentialenergyandthesizeofheadlossLowcarbonelectricityOperationAdoptionofmicroturbinestorecoverexcessiveenergyshouldbebalancedenergygenerationdepartmentinpipenetworkstogenerateelectricityThermalenergyextractionshouldnotdeterioratetheUtilizationofwaterqualitythermalenergyUsingHeatExchangersinPipelinestorecoverthermalSeawaterenergytoreplacefossilfuelenergyWideapplicabilitywithoutanycarbonemissionsdesalinationwithrenewableenergyCompletelyusecleanenergytorealizethedesalinationMakefulluseofthespaceofwatersectorsfornewenergyApplicationofprocessofseawaterpowergenerationtoreplacefossilenergyconsumptionrenewableenergyApplicationofcleanenergysuchaswindenergyandsolarenergy93Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector7.4.2Carbonreductionpathways7.4.2.1PipeleakdetectionAccordingtorelevantstandardsandregulationsofChina,theaveragewaterlossofurbanwatersupplypipelinesshouldnotbehigherthan10%.AccordingtotheChinaUrbanandRuralConstructionStatisticalYearbook(MHURDofChina,2020),thestateaveragewaterlossin2020is13.26%.Insomecities,thewaterlossevenexceeds25%.Thisnotonlycausesahugewasteofwaterresources,butalsoincreasedenergyconsumptionandcarbonemissionsinwatersupplysystems.Undoubtedly,theimplementationofleakdetectionwillhelptomonitor,locate,andrepairwaterlosspointsinatimelymanner,wherebycarbonemissionintensityofthewatersupplysystemcanbereduced.Infact,theexplorationanddevelopmentofleakdetectionhasalwaysbeenanimportanttopicinthewaterindustry.Forexample,theadvancementofsensorsandwirelesstransmissiontechnologyenablesthereal-timemonitoringofwaterpressureandflowbasedonwhichwaterlosscanbedeterminedandthensolvedinwaterdistributionsystems.Inafull-scaleproject,aleakdetectionsystemwasbuiltforawaterdistributionsystemservingapopulationof150,000.Theresultsshownthatthesystemhelpedtoavoid2.0×108m³waterleakageand104tCO2-eqemissionsover12years’running.7.4.2.2NewseawaterdesalinationtechnologyDesalinationisanimportanttechnologicalsolutiontourbanwatershortages.However,fromatechnicalpointofview,theproductionprocess,whetherdistillationorreverseosmosis,oftenrequireslargeamountsofelectricityorfossilfuelssuchascoal,whichresultsinhighlevelsofcarbonemissions(Ayazetal.,2022).Forthisreason,anumberofnewdesalinationtechnologiesaregraduallybeingdevelopedthatconsumelessenergyandhavelowertotalcarbonemissions,suchasthedeep-seadesalinationtechnologyandthehigh-efficiencyabsorptionvaporcompressionsystemprocess(Fasanoetal.,2021;Wangetal.,2020).Theformerisadesalinationunitsubmergedontheseabed,usingnaturalhydrostaticpressureasthe“pre-membranepressure”,andthedesalinationunitisconnectedtothecoastthroughacorridorthatconnectselectricity,communicationcablesandtreateddesalinatedwater,reducingcarbonemissionsby40%comparedtoconventionaldesalinationprocesses.Thelatterreducestheneedforexternalheatingsteambyreusingthefinalsteamgenerated,therebyreducingcoalconsumptionandreducingindirectcarbonemissionsfromoperationandmaintenancebyapproximately73%.7.4.3Carbonreplacementpathways7.4.3.1WaterenergyrecoveryAsanenergycarrier,watercontainsmanyformsofusableenergy,includingpotentialenergyfrompressurizationanditsownthermalenergy.Ifthisenergycanbepotentiallyrecoveredthroughavailabletechnologies,itcanfeedbackintotheenergyconsumptionofthewatersupplysystem,therebyreducingfossilfuelconsumptionandaccomplishingcarbonreduction.Theexcessenergy(waterhead)ofthewaterinthenetworkcanberecoveredusingmicroturbinepowergenerationtechnology,which,basedonthecurrentlevelofoperationofthewatersupplynetwork,cangenerateuptomillionsofkWhperyearwithoutaffectingtheeffectivewaterheadinthenetwork,andcanbeusedasapowersourceforintelligentmonitoringdevicesinthenetworksystem(Amjadietal.,2020).Inaddition,thelowandmoreconstanttemperatureofthewaterinthenetworkcanbeusedasacoolingsourceforwatersourceheatpumpsforbuildingcooling.Moreover,urbancivilbuildingsareconnectedtoanetworkofdistributionpipesandcanguaranteea24hsupply,ensuringthestabilityofwaterasacoolingsource.Thus,approachescouldproducecarboncredittooffsetthecarbonemissionofwatersectors(MeggersandLeibundgut,2011).94Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersector7.4.3.2NewseawaterdesalinationtechnologyCleanenergycanalsobeleveragedtosupportwatersupplysystems,particularlyforseawaterdesalination.Anumberofnewdesalinationtechnologiesusingcleanenergyarecurrentlybeingdeveloped,avoidingasignificantportionofthecarbonfootprintasfossilfuelsarenotrequired.Forexample,largeconcentratingsolardesalinationtechnologies,whichboilseawaterbybuildinghugeglassdomestoconcentratelightandheatthewater.Theinstallationcomeswithenergystorage(over4GWofenergystorage)fornightorcloudydayproduction(Ahmedetal.,2022).7.5WASTEWATERMANAGEMENTSYSTEMS7.5.1OverviewDuetothehighconcentrationoforganicmattersandnitrogencompoundsinwastewater,carbonemissionofthewastewatermanagementsystemintheoperationandmaintenancestagearedifferentfromothersystems.Morespecifically,thereareconsiderableamountsofCH4andN2Oemissions(directcarbonemissions).Accordingtotheabovecarbonaccountingandliteraturereview,thedirectcarbonemissionsourcesofthewastewatermanagementsystemincludeseptictanks,wastewatersewers,combinedsewageoverflow(CSO),biologicalwastewatertreatment,andfacilitiesforsludgetreatmentanddisposal.ItisestimatedthattheannualtotalamountofCH4producedbyurbanseptictanksinChinaisashighas3×107tCO2-eq/a(Haoetal.,2017),whichisatthesamelevelasthetotalcarbonemissionfromwastewatertreatmentplants(WWTPs),andisnecessarilythekeygoalofdevelopingcarbonemissionreductionplansforwastewatercollectionnetworks.Forwastewatertreatmentplants,thedirectcarbonemissionscausedbywastewaterandsludgetreatmentunitsaccountforabout35%to65%(Gallego-SchmidandTarpan,2019),whichisrelatedtoinfluentcompositionandoperationparameters.Thus,directcarbonemissionisthefocusforcarbonemissionreductioninwastewatertreatmentplants.Overall,intermsofcarbonemissionreductionpathwaysinwastewatermanagementsystem,thesituationcanbeconsideredandanalyzedfromtheperspectiveoffourtypesofactionstrategiesasdepictedinFigure7.6.Intermsofsourcecontrol,reducingtheamountofwastewaterandthetotalamountofpollutantsenteringwastewatersewersandwastewatertreatmentplantswillundoubtedlyreducetheenergyconsumption,materialinputanddirectcarbonemissionsrequiredforliftingortreatingwastewater.Possibleactionstrategiesincludetheimplementationofseparateddrainagesystems,sourceseparationtechnology,etc.Sourcecontrolalsohasitsownuniqueaspect,thatis,toformulatethedischargestandardsofwastewatertreatmenteffluent.Thedischargestandardshouldbeadoptedspecificallyandflexiblyaccordingtotheconditionofthereceivingwaterbodyinsteadofone-size-fits-allstandardwherebytheenergyconsumptionforwastewatertreatmentcanbeoptimizedtoachievecarbonemissionreduction(Buonocoreetal.,2016).Intermsofprocessoptimization,arangeofmeasurescanstillbetakenbywastewatermanagementsystems,withthepotentialtoreducecarbonemissions.Forexample,thecross-sectionandslopeofwastewaterpipescanbeoptimizedtoreducetheformationofanaerobicenvironmentandthusreducethegenerationofCH4.TheoperationparametersofbiologicaltreatmentprocessescanbeanotherhotspotinfluencingtheemissionsofCH4andN2O(Haoetal.,2019b).Moreover,aerationoptimizationcombinedwithwaterpumpoptimizationcanalsoreduceelectricityconsumption,therebyreducingindirectcarbonemissions.Intermsofthetechnologyupgradingstrategy,theresearchanddevelopmentofnew,low-energy,low-carbon,high-efficiencywastewatertreatmenttechnologyhasalwaysbeenahotspotinthewatersector.Inrecentyears,withtheproposalandapplicationofcompactandefficientnitrogenremoval95Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorprocesses,ithasbecomepossibletoachievecarbonemissionreductionthroughtheupgradingofnewtreatmentprocesses.Intermsoflow-carbonenergy,thewastewatermanagementsystemalsohasitsownadvantagesaswastewatercontainschemicalenergyaswellashugeamountsofthermalenergy.Typically,thethermalenergyembodiedinwastewateraccountsfor40%ofthetotalwasteheatofacity,andninetimesthatofthechemicalenergyinwastewater(Haoetal.,2019a).Relyingonanaerobicdigestionandwatersourceheatpumptechnology,theenergyinwastewatercanberecoveredandsupporttheoperationofwastewatertreatmentplantsorevenexportoutside.Allthesepracticescouldhelpthewatersectorachievecarbonreduction.Overall,thespecificcarbonreductionactionstrategiesforwastewatermanagementsystemsaresummarizedinTable7.4.Figure7.6Carbonreductionroadmapforwastewatermanagementsystems.96Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorTable7.4Summaryofactionstrategiesforcarbonemissionreductioninwastewatermanagementsystem.TypeStrategyAuthorityTechnicalrecommendationImplementationnotesUnnecessarilystringenteffluentdischargestandardscouldleadPlant-specificManagementItisnotnecessarytoadoptaone-size-fit-alldischargetomoreelectricityandchemicalinputinWWTPsandresultineffluentstandardforeachWWTP.Instead,plant-specificmorecarbonemissions.ItisnecessarytoestablisharegulardischargeOperationstandardishighlyrecommended,onesthatconsidermonitoringofthereceivingwaterbodyqualityandadjustthestandardsdepartmenttheenvironmentalcapacityofthereceivingbodyanddischargestandardsaccordingly.Alow-pollutedwaterbodyeffluentreusepurpose.couldacceptmorepollutantsandreducethetreatmentburdenSourceStrengtheningofWWTPs,therebyreducingcarbonemissions.ItisalsoworthcontrolindustrialThequalitystandardofindustrialwastewaternotingthattheimprovementofthequalityofthereceivingwastewaterdischargingintowastewatercollectionnetworkbodyreliesonthesynergicactionsandeffortsofothermanagementshouldbescientificallyformulatedtoavoidinputofindustriesordepartments.toxiccompoundsorwastewaterwithunbalancedPromotionoforganictonutrientratios.ItisnecessarytoestablishregularsupervisionoftheindustrialsourceBlackwaterandurinecanbecollected,conveyed,wastewaterqualitydischargedtothecollectionnetwork.separationandhandledseparatelytorecovernutrients,savetechnologywaterdemand,andreducethepollutantinputtoSanitaryappliancesarenotwithintheorganizationalboundaryWWTPs,therebyreducingcarbonemission.ofwastewatermanagementsystem,buttheydobenefitProcessCurbingCH4Moreover,nutrientsrecoveryandreusecouldproduceWWTPs.Investmentanalysisisrequired,andpolicy&carboncredits.regulationsarenecessarytoenhancetheattractivenessofthisoptimizationgenerationintechnology.Typically,withsourceseparationappliances,47-Effortsshouldbeallocatedtoavoidformationof95kgCO2-eq/(ca·a)carbonemissionsofwastewatertreatmentanaerobicenvironmentanddeadzoneinsewersbyplantscanbeachieved(Haoetal.,2016).Chemicaldosingandforcedventilationrequirecosts,energyconsumption,andcarbonemissionanalysisinordertoavoidContinued97Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTypeStrategyAuthorityTechnicalrecommendationImplementationnoteswastewaterchemicaldosing,flowoptimization,andforcedthetrade-offofcarbonemission.sewersventilation,therebyreducingtheproductionofCH4.ElectricalconsumptionismainlyduetotheliftingInvestmentanalysisshouldbedonebeforeadoptingtechnologyReductionofpumpandaerationsystem.Byupdatingandupgradingorprocessoptimizationtoincreasetheeconomicpowerupgradingequipment,oroptimizingtheoperation,thefeasibility.Itisworthnothingthatthepotentialoftheseconsumptionworkingefficiencyofpumpscanbeimprovedandapproachesforcarbonreductionishighlyplant-specific.TheelectricalconsumptionandcarbonemissionscanbeoptimizationofaerationsystemsshouldconsiderdirectReductionofreduced.Specifically,variablefrequencypump,highgreenhousegas(GHG)emissionssimultaneously.Typically,bydirectcarbonefficiencyaerationsystems,micro-bubbleaerationimplementingthesemeasures,energyconsumptioncanbeemissionsfromheads,andforwardfeedbackorpost-feedbackreducedby20%to50%(Lundinetal.,2000).wastewateraerationoptimizationcontroltechnologyaretreatmentunitsrecommended.Thisdigitaltechnologyhasbeenalreadyappliedinfull-scaleTheoperationofbiologicaltreatmentunitscanbeprojects(Limetal.,2012),butitsapplicationinGHGemissionOptimizationofoptimizedintermsofparameters,aeration,andothercontroldependsonthedevelopmentofsensors,controlexcesssludgemeasurestoreduceCH4andN2Oproduction.electricalequipment,etc.treatmentSpecifically,mathematicalmodelsordigitaltwinscanbeappliedtoguideoperationaladjustmentstoSystemsshouldbeconsideredanddesignedinconjunctionminimizeCH4andN2Oemissions(Manninaetal.,withenergyrecoveryfromsludge.2016).Wastesludgeshouldbeprocessedinatimelymannerandavoidlong-termstackingintheplants.Sludgevolumeshouldbereducedasmuchaspossiblepriortotransportationtolandfilling,therebyreducingcarbonemission.Continued98Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorTypeStrategyAuthorityTechnicalrecommendationImplementationnotesSomeinnovativetreatmenttechnologies,suchasItisnoteworthythatsomenoveltechnologiesrequirealargeTechnologyLow-carbonDesigncompactnitrogenremovalprocessand/oraerobicinvestmentandareprobablynotsuitableforupgradingexistingupgradingwastewaterplanninggranularsludge,canbeappliedtoreduceelectricityplants.Besides,althoughsomenewtechnologiescanreducetreatmentdepartmentandchemicalconsumption,therebyreducingcarbonpowerorchemicalconsumption,theyprobablyproducemoretechnology&emissions.directcarbonemissions,suchasCH4andN2O.managementResourcerecoveryfromwastewater,suchasPolicyandregulationsshouldbeformulatedtopromotePromotionofdepartmentnutrients,cellulose,etc.,shouldbegivenprioritytoresourcerecoveryandrecycling.Investmentanalysisshouldberesourceproducecarboncredit(Haoetal.,2022).donepriortoimplementation.recoveryManagementTherecoveryofchemicalenergyandthermalenergy&containedinwastewatercanfueltheoperationofTheinvestmentofsludgeanaerobicdigestionfacilitiesishugeLowcarbonStrengtheningoperationWWTPsandreducetheconsumptionoffossilfuelviaandneedsthesubsidysupportfromgovernment(Ashrafi,etenergywastewaterdepartmentanaerobicdigestiontechnology(supplementedbyal.,2014).Therecoverypotentialofthermalenergyislarge,energyrecoverythermalhydrolysispretreatmentorhighsolidbuttherecoverypointsandapplicationscenariosshouldbe&useofcleanconcentration)andwatersourceheatpumpbalancedanddeveloped.Thegovernmentshouldformulateenergytechnology(Haoetal.,2019a).Inaddition,solarandpolicyorientationtoallowthegeneratedCH4andthermalwindenergycanalsobeleveragedtofueltheenergytoenterthegrid.Also,thephotovoltaicpoweroperationofWWTPs(MoandZhang,2013).generationcapacityofaplantislimited.99Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector7.5.2Carbonreductionpathways7.5.2.1SourcecontrolThewastewatertreatmentfacilitiesinWWTPs(e.g.,aerationandmixing)consumeagreatdealofenergyandchemicalstoremove/destroypollutants,whichleadstotheproductionofindirectGHGemissions.Indeed,thebiochemicalprocessesofpollutantsalsoemitCH4andN2Odirectly.ThismeansthattheWWTPsmeettheeffluentdischargestandardatthecostofincreasedGHGemissions.Therefore,tryingtoreducethepollutantloadingofWWTPscouldreducethetotalcarbonemission,whichisclassifiedasasourcecontrolpathway.OneofthemeasuresthatcanbetakentoreducethepollutantsinwastewaterfromflowingintoWWTPsissourceseparation.Theessenceofsourceseparationtechnologyistocollectandprocessblackwaterandurineseparately(BisinelladeFaria,etal.,2015).Inthisway,thenutrientscontainedinurinecaneasilybecapturedandrecycledwhichmeanstheycouldthenbeusedinagriculturalproduction.Atthesametime,sourceseparationreducestheamountsofpollutants,particularlynutrients,enteringtoWWTPs.Assuch,electricalandchemicalconsumptioncanbeminimized,therebyreducingthecarbonemissionintensityofwastewatertreatment.Itisestimatedthattheapplicationofsourceseparationcanreducecarbonemissionsbyabout47-95kgCO2-eq/(ca·a)(Haoetal.,2016).Asstatedabove,WWTPsachievepollutantremovalatthecostofGHGemissions.Stringenteffluentdischargestandardcanreducethepollutantinputtothewaterbodiesandavoidenvironmentalproblemsofblackandodorouswaterbodiesandeutrophication,andanevenmorestringentdischargestandardusuallyonlymeansmoreGHGemission.Indeed,forsomeWWTPs,aone-size-fit-allstringentdischargestandardisnotnecessaryprobablyduetothelargeenvironmentalcapacity.Therefore,aplant-specificdischargestandardisrecommendedtobalanceeffluentqualityandcarbonemissions.SinceChinahasalargeareacoveringarangeofclimatezones,wastewatercharacteristicpresentsdifferences.Therefore,alocaldischargestandardshouldbescientificallyformulated(MoandZhang,2013).Ingeneral,industrialwastewatercanbedischargedintomunicipalwastewatersewersaftertreatmentandmeetingqualityrequirements.However,therearealwayssomecompaniesillegallydischarginguntreatedindustrialwastewaterintosewers.ThearbitrarydischargeofindustrialwastewaterwillincreasethepollutantloadingofWWTPs.Moreover,toxicandharmfulsubstancesinindustrialwastewaterwillaffectbiologicaltreatmentperformance.Thus,itisnecessaryforthewaterdepartmenttoimplementstrictsupervisiontoreduceunnecessarycarbonemissionfromWWTPs.7.5.2.2DigitaltransformationofwastewatertreatmentRelyingonthedevelopmentofdigitaltools,WWTPscanuseavarietyofsensorstocollectdetailedinformationandusemathematicalmodelandcontrolstomakedecisionsandoptimizetheefficiencyofwastewatertreatment.Thecoreofadigitaloperationisascientific,reliableandaccuratemathematicalmodelrepresentingthephysicalassetsoftreatmentunits(Chengetal.,2023).Themodelisrunningbasedonalargenumberofoperationaldataandcansimulateandpredicttheinfluenceofchangingparametersonperformance.Then,themodelcanalsoproposesolutionstooptimizetheoperationofwastewatertreatmentprocesses,suchastheaerationintensity,flowcontrol,chemicaldosage(Therrienetal.,2020).Then,energyandchemicalinputcouldbeminimized,therebyreducingcarbonemissions.Onehighlightedapplicationofthedigitaltoolsistheaccurateaerationinbiologicalwastewatertreatmentunits.Typically,aerationinwastewatertreatmentaccountsforapproximately50%ofthetotalenergyconsumptioninwastewatertreatmentplants(Sweetappleetal.,2014).Iftheaerationintensityisinsufficient,itwillaffectthemicrobialbiochemicalreaction,therebyimpairingthepollutantremoval100Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorperformance.Assuch,aerationintensityisusuallycontrolledatasurplusandconstantlevelwhichisindependentofwastewaterorpollutantfluctuations.Asaresult,itwillleadtohighenergyconsumptionandcarbonemissions.Assuch,digitaltoolsenableoptimalcontroloftheaerationprocessbyadvancedmonitoringofdissolvedoxygen(DO),NH+4-N,andevensuspendedsolids(Haimietal.,2013).Thecontrollerbasedonmathematicalmodels,cangivefeedbacktotheblowersandadjustaerationintensityinrealtime.Assuch,electricityconsumptioncanbeminimizedwithoutexacerbatingthetreatmentperformance.Itisworthnotingthattheperformanceofdigitaltoolsinaerationcontrolishighlydependentonthedevelopmentofinstruments,e.g.,sensors(Therrienetal.,2020).Pumpoptimizationwithdigitaltoolsisalsooneofthemostimportantapproachestoreducingelectricalconsumptionandcarbonemissions(Fanetal.,2018).Withtheoperationofpumps,theworkingefficiencyisnotalwaysashighasitisdesignedtobe,andmaybecompromisedthroughlong-termuse.Therearetworeasonsforthis:firstly,componentsmaybecomedamagedaftercontinuousoperation,resultinginagradualdecreaseandlossofpumpefficiency.Inaddition,pumpsdonotalwaysworkatpeakefficiencyduetothefluctuationsinwastewaterflow.Asaresult,unnecessaryelectricalconsumptionleadstofurthercarbonemissions.Intermsofsolutions,existingpumpscouldbeswitchedtosmartpumpingbyleveragingdigitaltools.Theemergenceofpumpswithembeddedintelligenceisacriticalstepforwardintheevolutionofperformancemanagementandpumpsystemoptimization.Intelligentpumpcontrollerscanautomaticallyconfigureasystemwiththeoptimalsettingsfortheirapplication,takingtheguessworkoutoftheprocess.Systemscanbecustomizedwithpumpprotectionsandformultiplepumpoperations.Curvecontroltechnologyreliesonpump-specificalgorithms,whichcanaccuratelypredictwhereapumpoperatesonitscurve.Usingspeed,torqueandpowerdatatoknowwherethepumpoperatesonthecurve,sensorlesspumpcontrollerscanbesetuptotakeactionsbasedonthosefactors.Overall,therearemanycasestudiesofcompaniesprovidingthisservicetooptimizetheirpumps,therebyreducingcarbonemissions.7.5.2.3CompactwastewatertreatmentprocessesCurrently,conventionalactivatedsludgeiswidelyappliedinWWTPs.However,oneofthedisadvantagesofconventionalactivatedsludgeisthelowbiomasscontentinthereactors.Asaresult,thefootprintofbiologicalreactorsisusuallylarge,whichmeanthatmoreconstructionandbuildingmaterialsareneeded,whichinturngenerategreatercarbonemissions.Inaddition,thelargevolumeofthereactorsneedsmoremixerswhichresultsintheirusingmoreelectricity.Thisshowsthenecessityofmorecompactwastewatertreatmenttechnologies.Aerobicgranularsludgetechnologyisaninnovativewastewatertreatmenttechnologythatprovidesadvancedbiologicaltreatmentusingtheuniquefeaturesofaerobicgranularbiomass.Thesetechnologicalfeaturestranslateintoaflexibleandcompactprocessthatoffersenergyefficiencyandsignificantlylowerchemicalconsumption.Thereactorfootprintofaerobicgranularsludgesystemisusuallyonly1/4thatofconventionalactivatedsludgesystems(Bengtssonetal.,2019).Moreover,thistechnologyreducesenergyconsumptionby30%to50%(Hamzaetal.,2022).7.5.2.4EfficientdenitrificationtechnologyThebiologicalnitrogenremovalprocessiscomposedofanaerobicenvironmentandananoxicenvironmentwhereoxygenandacarbonsourcearerequired,respectively.Forwastewaterwithalowcarbontonitrogen(C/N)ratio,anexternalcarbonsourceshouldbesupplementedtoachieveeffluentstandard.Allthesefeaturesleadtocarbonemissionduetoelectricalandchemicalconsumption.Since,101Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorthisprocessisalsothemaincontributortoN2Oemission,itshouldreceivethegreatestattention.Somenovelnitrogenremovalprocesseshavebeenproposedandevenappliedinfull-scaleprojects,suchaspartialnitrification-denitrificationprocessandANAMMOXprocess.Theoxygendemandandcarbonsourcesinthesenovelprocessesisreducedcomparedtotheconventionalprosses,asaresult,carbonemissionsareminimized.ItisworthnotingthatN2Oemissionsinthesenovelprocessesneedmoremonitoringtoconfirmtheirpreciselevels(Vasilakietal.,2019).7.5.2.5ResourcerecoveryfromwastewaterItisaconsensusthatwastewateristhecarrierofvariousresources(Haoetal.,2022),suchasphosphorus,nitrogen,cellulose,EPS,etc.Theycanberecovered,andbringcertaineconomicbenefitsandcarboncreditsbyreplacingtheminingandproductionprocessoftheindustrialproducts,andtherebyreducingcarbonemissions.Phosphorusrecoveryfromwastewaterhasbeenahotspot,astheconservationofphosphaterockislimitedandphosphorusisanecessaryelementforlifeandmodernagriculture.Atpresent,phosphorusrecoverytechnologycanbedividedintothreecategories:i)recoveryfromthemainstreamtreatmentline,i.e.,thesupernatantoftheanaerobictankrichinphosphoruswitharecoveryefficiencyof40%-50%(Juppetal.,2021);ii)recoveryfromsludgetreatmentline,i.e.,theside-streamliquidfromtheanaerobicdigestionand/ordewateringunits;iii)recoveryfromtheashaftersludgeincinerationwitharecoveryefficiencyof90%(Wangetal.,2023).Anotherexampleistherecoveryofhigh-valuedalginate-likeexopolymer(ALE)fromwastesludge.ALEisamixtureofbiopolymersextractedfromtheextracellularpolymericsubstancematrixofbacterialaggregate(Lietal.,2021).ALErecoveredfromwastesludgecanbeusedtoproduceflameretardants,absorbinggels,inkthickeners,gluingagentsforfertilizerpellets,corrosioninhibitors,coatingsforimprovingthewaterresistanceofpaper,orfire-resistantboards(Lietal.,2022).Overall,manyresourcerecoverytechnologieshavebeenappliedinfull-scaleprojectsandshouldbepromotedtoreducethecarbonemissionofWWTPs.7.5.3Carbonreplacementpathways7.5.3.1ChemicalenergyrecoveryWastewatercontainsalargeamountoforganicmatter,whichcanberecoveredandconvertedintobiogasthroughananaerobicdigestionprocess,andthenconvertedintoheatorelectricitythroughcombinedheatandpower(CHP)(Haoetal.,2020).Theelectricityandheatrecoveredcanbeusedwithintheplantstoreduceelectricityimportandcarbonemissions,suchasfuelingaerators,pumps,andanaerobicdigestion.Besides,thesurplusenergycanalsobeexportedtothegridandgeneratecarboncredits.Currently,afewWWTPsgloballyhaveachievedenergyneutralityrelyingananaerobicdigestionprocessorco-digestionwithfoodwaste(Camposetal.,2016).Itisworthnotingthattheenergyrecoverypotentialofanaerobicdigestionishighlyassociatedwithinfluentorganiccontent.InChina,anaerobicdigestionisnotwidelyusedinWWTPs,partlyduetotheloworganiccontentininfluentaswellasthehighcontentofinorganicmatterinsludge.Asaresult,biogasproductionefficiencyislowandnotattractive.Evenifanaerobicdigestionispromoted,thecapitalcostwillbringaheavyeconomicburdentoWWTPs(Chaietal.,2015).IncinerationofsludgeafterdewateringhasbeenproposedasanalternativetoanaerobicdigestionandamoresuitablepathwayforChina.Throughincineration,theorganicenergycontainedinthesludgecanbemorecompletelyreleased,andconvertedintoelectricityandheatviaCHP(Haoetal.,2020).Moreover,theashfromincinerationcouldbeusedforphosphorusrecovery(Wangetal.,2023).102Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersector7.5.3.2ThermalenergyrecoveryIntermsofthesourcesofwastewater,partofthemcomesfromkitchensandbathroomwherethehotwaterissupplied.Assuch,thewastewaterdischargedintothedrainagepipeshasastabletemperature.Giventhestableflow,wastewatercanbeahigh-qualityheatsourcewhichcanbeutilizedbythewatersourceheatpump(WSHP)technology.Therearetwopointswherethethermalenergyinwastewatercanbeutilized:drainagepipesandtheeffluentofWWTPs.Energyextractionatthedrainagepipesprobablyhasanadverseimpactonthefollowingtreatmentprocessesandhascorrosiveproblems.Thus,thermalenergyrecoveryfromtheeffluentofWWTPsispreferable.Itshouldbenotedisthattheheatextractedfromwastewaterisakindoflow-gradeenergy(40-80℃),whichisdifficulttousedirectlyforpowergeneration(Haoetal.,2019a).Thus,theheatcouldbeutilizedwithintheplant,forexample,foranaerobicdigestionwarmingorsludgedrying.Then,thesurplushearcouldbeexportedtoresidentswithinaneconomicdistanceof3-5km(Haoetal.,2019a).Intermsofthermalenergyrecoverypotential,Haoetal.(2019a)presentedadetailedcalculationandcomparison.Whenenergyisextractedby4℃,thetheoreticalthermalenergyis4.64kWh/m3(Haoetal.,2019a).TheachievablethermalenergycapacitysuppliedbyWSHPcanbecalculatedthroughthecoefficientofperformance(COP,thetypicalvalueofwhichisintherangeof3~5).Forheatingpurposes,thenetelectricalequivalentis1.77kWh/m3(38%ofthetheoreticalthermalenergy,COP=3.5).Whenusedforcooling,thenetelectricalequivalentis1.18kWh/m3(25%ofthetheoreticalthermalenergy,COP=4.8)(Haoetal.,2019a).Theamountofthermalenergythatcanberecoveredis6~8timeslargerthantheamountofchemicalenergy.7.6STORMWATERSYSTEMS7.6.1OverviewCarbonemissionsofstormwatermanagementsystemsmainlycomefromtheplanningandconstructionstage.Intheoperationandmaintenancestage,thepumpingstationinthestormwatersewersalsomakecontributionstocarbonemissions.Assuch,toreducecarbonemissionsfromstormwatermanagementsystems(Figure7.7),planningandconstructionshouldbethefirstconcern,andgreeninfrastructuresandgreenbuildingmaterialsshouldbegivenpriority.Intheoperationstage,thecarbonemissionamountisassociatedwiththeamountofstormwaterhandledbythesystem,particularlyforthepumpingstationsinstormwatersewers.Thus,sourcereductionviagreeninfrastructuresand/orseparateddrainagesystemsshouldbepromotedandgravityflowdrainageispreferable.Besides,theintegrationofthestormwatersystemandtheurbanecosystemhasgreatpotentialtoachievecarbonemissionreductionbyrainwaterrecycling,beingheatsinks,andCO2sinksofvegetation.Intermsofsourcecontrol,reducingtheamountofstormwaterintothedrainagesystemisakeysolution.Priorityisgiventotheleverageofgreeninfrastructurestoachievesourcereduction.Assuch,naturalstorage,infiltration,purificationandsustainablewatercirculationofrainwatercanbeachieved,whichcanalsoeffectivelyachievemultiplegoalssuchaswaterloggingmitigationandwaterenvironmentimprovement.Intheplanningandconstructionofstormwatersystems,givingprioritytotheuseofgreenfacilitiesandgreenbuildingmaterialscangreatlyreducecarbonemissions.Intermsofprocessoptimization,thekeyistogiveprioritytogravityflowdrainagesystemsandimplementseparateddrainagesystems.Theformerapproachcangreatlyreducetheelectricalconsumptionofpumpingstations,andthelattersolutionisnotonlyconducivetosubsequentrainwaterreuseandreductionofCSOpollution,butalsoconducivetocarbonemissionreductioninthewastewatermanagementsystem.Besides,stormwatertreatmentplantsanddeeptunnelprojectsaremainlylarge-103Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorscalegrayfacilities,withhugecarbonemissionsfromplanningandconstruction,andoperationandmaintenancealsoinevitablyleadtocarbonemissionfromthepumpingstation.Thus,thesegreyfacilitiesshouldbethefinalsolutiontocaterfor.Intermsoftechnologyupgrading,thekeyismaximumutilizationofrainwaterinsteadofdrainage.Rainwaterisanimportantnon-traditionalwatersource,asitcannotonlysavewaterresources,butalsoeffectivelyreducethecarbonemissionofthewatersupplysystem.Atthesametime,thestormwatermanagementsystemandtheurbanecosystemareintegratedwitheachother,andcanprovidecoldsourceandspaceresources.Thus,thecoolingenergyconsumptionofthebuiltenvironmentcanbeminimized.Besides,stormwatermanagementsystemscanalsoprovidelargespacestodeveloprenewableenergysourcessuchasphotovoltaics.Intermsofcarbonremoval,greenfacilitiesarethekey.Theuseofgreenfacilitiesinthestormwatermanagementsystem,suchasgreenroofs,raingardens,grassditches,bioretentionponds,etc.,canachievethegoalofrainwaterrunoffcontrolandimprovethelivingenvironment,aswellashavingabettercarbonsinkcapacity.ThespecificactionstrategiesforstormwatermanagementsystemsareshowninTable7.5.Figure7.7Carbonreductionroadmapforstormwatersystem.104Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersectorTable7.5Summaryofactionstrategiesforcarbonemissionreductioninstormwatermanagementsystems.TypeStrategyAuthorityTechnicalrecommendationImplementationnotesTheurbanizationandgreybuildingdensityshouldbeThenecessaryurbanhydrologicalcycleshouldbeensuredtoimprovetheinfiltration,retentionandbalancedwiththenaturalandecologicallandtokeepthestorage,purification,utilizationanddischargecapacityofrunoff.SourceSourcereductionDesignandnecessaryproportionofimperviousareas,andtominimizecontrolplanningdamagetotheoriginalwaterecologicalenvironmentoftheToreduceoperationenergyconsumptionandcost.departmentcity.Atthesametime,rivers,lakesandditchesshouldbeappropriatelyexcavatedtoincreasethewatershedarea,andWaterpollutioncanbecontrolled,andwaterloadingofWWTPsandstormwatermanagementthecapacityofrainwaterretention,infiltrationandsystemscanbereduced.Rainwaterharvestingcanincreasetheamountofpurification.availablewaterresources.ToadjustandoptimizetheoperationmodeofthepumpingGreenfacilitiescanimprovetheresilienceofcities.ProcessGravityflowDesignandstationaccordingtothewatervolume,determinethebestFlexibletoimplement,effectiveenergysaving,managementRainandplanningpumpingscheme,usegravityflow,reducetheuseofcarbonemissionreduction.departmentpumpingsystem,andsaveenergyconsumption.ContinuedwastewaterToimplementseparateddrainagesystems1diversionUtilizationofRainwatercollection,purification,storage,andreuseforrainwaterirrigation,toiletflushing,carwashing,alternativewaterresourcessources,etc.ResourceUtilizationofcoldOperationGreenfacilitiesshouldbegivenprioritytosequestrateCO2utilizationsourcesforgreendepartmentandreducebuildingenergyconsumptionandsavewaterfacilitiesconsumption.UtilizationofGreenspacecanbeusedtodevelopandbuildphotovoltaicgreenfacilitypowerstations.space105Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTypeStrategyAuthorityTechnicalrecommendationImplementationnotesPlantsinkAdoptgreenfacilitiesinthestormwatermanagementsystem,IthasagoodcarbonsinkfunctionwhilerealizingPlantsinksuchasgreenroofs,raingardens,grassditch,bioretentionthetargetofstormwaterrunoffcontrolandtechnologyponds,etc.improvingthelivingenvironment.106Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersector7.6.2Carbonreductionpathways7.6.2.1SourcereductionTheessenceofsourcereductionistobuildstormwatercontrolfacilitiestoleveragenaturalsystemstoreducestormwaterrunoffthroughdecentralizedfacilities.Thereductionofthetotalamountofrainwaterrunoffcaneffectivelyreducethecarbonemissionsofstormwatermanagementsystems.Typically,thetotalannualrunoffcontrolrateof60%canbeachievedbysourcereduction(Linetal.,2018).Withreferencetooperationenergyconsumptionofthepumpingstation,powerconsumptionperunitflowforsinglepumpandthedoublepumprunningatfullspeedis45.50-54.40kWh/103m3(Suetal.,2022).Thus,inthecaseofdrainagebyapumpingstation,totalrainwaterrunoffcontrolcanreduceCO2emissionsby26.57-31.76kg/103m3duringoperationandmaintenance(Linetal.,2018).7.6.2.2GreeninfrastructuresTheuseofgreenfacilitiesintheplanningandconstructionstagetoreplacereinforcedconcretefacilitiescansignificantlyreduceGHGemissions.Forexample,withthesamerainwatercontrolrate,thecarbonemissionintensityofreinforcedconcreterainwaterstoragetanksis513.32kgCO2-eq/m3(calculatedbywaterstoragecapacity),whilethecarbonemissionintensityofmostgreenfacilitiesisbelow200kgCO2-eq/m2,orevenbelow100kgCO2-eq/m2,withanemissionreductionrateofover80%(Suetal.,2022).Besides,thecarbonemissionofconcretelinedditchconstructionisabout50%ofthatofreinforcedconcretepipes,andthecarbonemissionofgrassditchconstructionisalmostzero(Linetal.,2018).Greeninfrastructurecanreducetheuseofnon-renewablematerials,reducetheamountofearthworkintheconstructionprocess,andhavealongerservicelifethangrayfacilitiesundernormalmaintenanceconditions.Attheendofservicelife,greeninfrastructurehasasmallquantityofbuildingwastetobedisposedof,whichgreatlyreducesthecarbonemissionsaswell.Inaddition,becausethelowinfiltrationcapacityofthegrayfacilities,thegrayfacilitiesoftenneedtobebuiltlargerandconsumemorebuildingmaterialstoachievethesamerainwatercontrolrate.Besides,theplantsinthegreenfacilitiescanactascarbonsinks.Therefore,inthecaseofmeetingthedesignneeds,itispossibletoconsidertheuseofgreeninfrastructuretoreplacethegreyfacilities,suchasecologicalditchesinsteadofgreyopenchannels.7.6.2.3GravityflowdrainagesystemThecarbonemissionsofthestormwatersewermainlycomefromthepumpingstation.Referringtotheoperationenergyconsumptionofthepumpingstation,thepowerconsumptionperunitflowusedbysinglepumpandadoublepumpinfullspeedoperationis26.57-31.75kgCO2-eq/103m3,andcarbonemissionsaccountforarelativelylargeproportion(Camposetal.,2016).Inthedesignofstormwaterpipelines,theminimumslopeandminimumflowrateshouldbeensuredbyconsideringthelocalgroundwaterlevel,theburydepthofthepipeline,andthedistancefromthedischargepoint.Overall,gravityflowdrainagesystemsshouldbegivenprioritywithnoorlessliftingpumpstations.7.6.2.4SeparateddrainagesystemThecombineddrainagesystemisasystemthatmixesdomesticwastewater,industrialwastewaterandrainwaterinthesamecanal.Theseparateddrainagesystemdischargesdomesticwastewater,industrialwastewaterandrainwaterintwoormoreindependentpipes.Inascenarioofacombineddrainagesystem,rainwateranddomesticwastewateraremixedintothesamepipelines.Whentheyenterthegreenfacilitiessuchasrainwaterwetlands,thetreatmentloadingofthefacilitiesincreasesduetothehigh107Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorconcentrationofpollutantsandpoorwaterquality,andthemicroorganismsandmoreorganicmatterinthemixedwateralsoincreasethecarbonemissionsofrainwaterwetlands.Thisproblemwillbeavoidedifaseparateddrainagesystemisadoptedtoensurelesspollutantsconcentrationandrelativelycleanwaterquality.Inaddition,rainwatercollectedbyseparateddrainagesystemscaneasilybereusedon-siteaftersimplesedimentationanddisinfection.Moreover,thecombineddrainagesystemconveysmorewastewatertoWWTPs,whichwillleadtomoreelectricalconsumptionandcarbonemissioninWWTPs.Besides,aseparateddrainagesystemcanreduceCSOpollutionand70%-80%ofwaterpollution(Camposetal.,2016).7.6.3Carbonreplacementpathways7.6.3.1UtilizationofrainwaterresourcesRainwaterhasthecharacteristicsofslightpollution,neutralpH,littlesaltcontent,andverylowwaterhardness,sothereisnoneedtosoftenit.Collectedrainwatercanbeusedfornon-drinkingpurposesaftersimpletreatment,andcanbedirectlyusedforwatering,flushing,carwashing,etc.Sincetherainwaterdoesnotentertheurbanrainwaterpipenetwork,itcanalsoreduceloadingoftheurbanfloodcontroldrainageandtreatmentsystematthesametime.Inareasofseverewatershortage,rainwatercanbeusedtoproducedrinkingwater.Theproductionofdrinkingwaterfromrainwaterisveryeconomical,andtheoperatingcostisestimatedtobe1.5-2.5CNY/m3(Duetal.,2019).7.6.3.2UtilizationofcoldsourcesforgreenfacilitiesGreeninfrastructurecannotonlyeffectivelyrespondtoclimatechangethroughitsownresilience,butcanalsouseitsowncharacteristicstoenhancetheresilienceofcitiesinthefaceofclimatechange.Greenfacilitiescangreatlyincreasethegreenareabyecologicalretentionfacilities,sunkengreenspaces,andgreenroofs.Theimprovementofgreenlandcoveragecansignificantlyimproveurbanclimateenvironments.First,plantscanabsorbalargeamountofheatthroughtranspiration.Greenvegetationitselfhasthefunctionofcarbonfixation.ItusesphotosynthesistoabsorbCO2,therebyreducingtheconcentrationofCO2intheatmosphere,inhibitingthegreenhouseeffect,andreleasingO2,whichresultsincoolingeffect.Secondly,thespecificheatcapacityofwateringreenspaceisconsiderable,andcancontroltherapidriseoftemperature.Finally,plantscanretaindustintheatmosphere,reducesolarradiationheatabsorption,andfurtherplayaroleinreducingtheheatislandeffect.Studieshaveshownthattheuseofgreeninfrastructurewillreducetheambienttemperatureby7-8℃.Byintegratingwiththeenvironment,greenfacilitiescaneffectivelyreducetheurbanheatislandeffect,therebyreducingbuildingcoolingenergyconsumption.Atthesametime,ithasapositiveimpactonthelivesandhealthoftheresidents.Themitigationoftheheatislandeffectprovidesresidentswithamorecomfortablelivingenvironmentandbetterindooraircirculation,whichreducestheincidenceofdiseasescausedbytheheatislandeffect.This,inturn,resultsina30%reductioninneurologicalmorbidity(Suetal.,2022).Theusetimeoftherefrigerationsysteminbuildingsisgreatlyreduced,savingalotofpowerconsumptionandindirectlyreducingCO2emissions.Takingthegreenroofasanexample,throughthetranspirationofplantsandlargeareasofshading,thusavoidingdirectsunlight,itcansignificantlyreducethetemperatureoftheroofsurfaceandthesurroundingambientair,therebyreducingtheenergyconsumptionofthebuildinginwhichitislocated.Studiesshowthatthesimplegreenroofgreeningsystemcansave6.31kWh/m2airconditioningofenergyconsumptionandreduceCO2emissionsby10.00kgCO2-eq/(m2a)peryear(Suetal.,2022).108Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonreductionpathwaysinwatersector7.6.3.3UtilizationofgreenfacilityspaceSolarenergyisacleanandrenewableenergysuitableforlocalandnearbydevelopmentandutilization.Thelargespaceofgreenfacilitiescanbeleveragedtoinstallphotovoltaicpaneltoproduceelectricityandachievecarbonreduction.Forexample,greenfacilitiessuchasgreenroofscantakeadvantageoftheirspacetoinstalldistributedphotovoltaicpowergenerationfacilities.Rainwatergardensatthebottomoftheplanecanmakefulluseofitssunnysidetoinstallsmallareaphotovoltaicpowergenerationfacilities,whiletheecologicalenvironmentofgreenfacilitiescanalsokeepthetemperatureofphotovoltaicmodulesinalowerrangetohelpimprovephotovoltaicpowergeneration,thusprovidingmoregreenenergyfortherainwatersystem.Aftertheuseofphotovoltaicfacilitiestogenerateelectricity,theenergyusedbygreenfacilitieswillshiftfromtraditionalenergytolow-carbonenergy.Forexample,photovoltaicpowergenerationfacilitiescanusesolarpowertoreplacetraditionalconventionalenergyusedonliftpumpsinstormsewersystems.Inaddition,photovoltaicpowergenerationfacilitiescanalsobeappliedtotheautomatedrainwaterirrigationdevicesforlandscaperainwatercontrolfacilitiessuchasraingardensorthepowersupplyofpubliclightingsystemssuchasgroundlights.7.6.4CarbonremovalpathwaysCarbonsequestrationreferstothelong-termstorageofatmosphericCO2asorganicmatterinplantsandsoils.Theareacoveredbygreenvegetationisthemainareatoproducecarbonsinks.Thesearedifferentfromotherwatersystems,inthatthegreenfacilitiesinthestormwatermanagementsystemcannotonlyachievethegoalofcontrollingthesourceofrainwaterrunoffandimprovethequalityofthelivingenvironment,butalsohavedifferentdegreesofcarbonsinkpotentialinthegreenspaceformedbythecombinationoffacilities.Inaddition,thegreenspaceoftherainwatersystemrelatestoothergreenareasinthecitytoformanurbangreennetworkcombiningpoint-line-surface,whichprovidesgreensupportforthecarbonneutralityofthewatersystem.Ecosystemswithhighbiodiversitycanabsorbandstoremorecarbonthanthosewithlowbiodiversity,andgreenspacescomposedofgreenfacilitieshavesignificantdifferencesintheircarbonsinkcapacityduringtheirlifecycle.Studieshaveshown(Table7.6)thatthecarbonsequestrationcapacityofthebioretentionfacilities,thevegetationfilterzoneandtherainwatergardenovera30-yearlifecycleisabout44.2±35.8kgCO2-eq/m2,2.3kgCO2-eq/m2,and75.5±68.4kgCO2-eq/m2,respectively(ZhouandLi,2009).Thecarbonsequestrationcapacityofagreenroofwitha40-yearlifecycleisabout58.4±24.7kgCO2-eq/m2(Suetal.,2022).Amongthemanygreenfacilities,vegetationbufferstrips,bioretentionfacilities,raingardens,andgreenroofsdemonstratesignificantcarbonsequestration.Therefore,accordingtoplannedregionalconditions,theproportionofgreenfacilitieswithsignificantcarbonsequestrationsuchasgreenroofsandraingardenscanbeappropriatelyincreased.Accordingtoregionalenvironmentalconditions,plantswithhighcarbonsequestrationcoefficientscanbeselectedasthemainvegetationingreenspaces.Forthespecificcarbonsinkpotentialofdifferentfacilities,fieldmeasurementsareneededtoobtainmoreaccuratedata.Inpracticalapplications,variousfactorsshouldbeconsideredcomprehensively,andconstructionshouldbeplannedandconstructedreasonablyaccordingtolocalconditions.109Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable7.6CarbonsequestrationamountoftypicalgreenfacilitiesforrainwatercontrolGreenfacilityBioretentionVegetationRaingardenGreenfacilityfilterstrip30roofLifecycle(a)3040Carbonfixationcapacity3075.5±68.444.2±35.858.4±24.7(kgCO2-eq/m2)8.57±2.3Intheactualplanningandconstructionapplications,factorssuchasgeographicallocation,climaticconditions,plantdiversity,andgrowthstatusshouldbeconsideredcarefully,andthespatiallayoutshouldbeoptimizedaccordingtolocalconditions,soastoimprovetheurbangreenspacesystemandachieveconsiderable“carbonrecovery”benefits.110Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter8Dataacquisitionandmanagement8.1OVERVIEWTheurbanwatersectorsencompassvarioustypesofsystemmodulesandcorrespondinglyinvolvemultiplecarbonemissionactivities.Therequireddatatypesandquantitiesforcarbonemissionaccountingdifferfordifferentsubsystemsandcarbonemissionactivities.Thedatarequiredforcarbonemissionaccountingofurbanwatersectorsmainlyconsistsoftwocategories,i.e.,activitydataandemissionfactors.Toenhancetheaccuracyandrepresentativenessofthedataandensuretheaccuracyofitsaccountingresults,thischaptersummarizesandstandardizesdatatypesandacquisitionsduringtheplanningandconstruction,operationandmaintenance,andassetreplacementanddemolitionstagesoftheurbanwatersectors.Fordatathatneedson-sitecollectionordetection,theexistingtechnicalstandardsorspecificationsarerecommendedandpreferred.Intheabsenceofcorrespondingtechnicalspecifications,thischapterprovidesliteraturereferencestoguidedatacollection.Itisnoteworthythatthroughouttheentireprocessofcarbonemissionaccounting,thereportingentityshouldstrengthenthemanagementofcarbonemissiondatacollectionandacquisition,including:•Establishcarbonemissionaccountingandreportingregulations,includingresponsibleinstitutionsandpersonnel,workflowandcontent,workcyclesandtimeframes,etc.Appointdedicatedpersonneltoberesponsibleforcarbonemissionaccountingandreporting.•Establishtheinventoryofcarbonemissionactivities,andidentifythekeyandmorecomplicatedactivitiesonwhichspecialattentionaboutdataandemissionfactorsshouldbeplaced.•Assessexistingmonitoringconditions,continuouslyimprovethemonitoringcapabilities,andformulatecorrespondingmonitoringplansofbothactivitydataandemissionfactors,etc.•Establishdatarecordingandreportingregulationandregularlymanageandmaintainmeasuringinstruments,equipmentoronlinemonitoringdevices.•Establishaninternalreviewsystemforcarbonemissionreporting.Conductregularcross-verificationofcarbonemissiondata,identifypotentialrisksofdataerrors,andproposecorrespondingsolutions.8.2ACTIVITYDATAACQUISITIONThecarbonemissionaccountingofthewatersupplysystemmainlyinvolvestheacquisitionofelectricalandmaterialconsumptiondata,whicharesummarizedinTable8.1.Forthewastewatermanagementsystem,inadditiontotheelectricityandmaterialconsumption,italsoinvolvesdataassociatedwithdirectcarbonemissionsduetobiochemicalprocesses.Thus,thedatarequirementsforcarbonemissionaccountinginwastewatermanagementsystemsaremorecomplex,assummarizedinTable8.2.Forwaterreclamationsystemsandstormwatermanagementsystems,therequiredactivitydataforcarbonemissionaccountingareshowninTable8.3andTable8.4,respectively.111Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable8.1Summaryofthesourceandacquisitionofdatarequiredforcarbonemissionaccountingofwatersupplysystem.StageActivitydataAssociatedDatarequirementsSources,referencespecificationsormethodsaccountingObtainedfromtheconstructioncompany’sledgerPlanningandTypesandamountsoffossilMonitoringtheentireObtainedfromtheconstructioncompany’sledgerconstruction1fuelconsumptionequationconstructionperiod2Obtainedfromtheconstructioncompany’sledgerTypesandamountsof(4-1)MonitoringtheentireObtainedfromtheconstructioncompany’sledgerOperationandmachineshifts3(4-2)constructionperiodmaintenance(4-3)MonitoringtheentireObtainedfromtheconstructioncompany’sledgerandelectricityconsumption(4-4)constructionperiodMonitoringtheentireOperationledgerorelectricitybillreceiptTypesandconsumptionof(4-5)constructionperiodconstructionmaterialsOperationledgerortheprocurementcontractAmountsofmaterials(5-2)Monitoringtheentiretransportedandcorresponding(5-3)constructionperiodMonitoringaccordingtoTechnicalspecificationsforwatertransportationtypeand(5-4)resources(Watervolume)monitoring(DB37/T3858-2020)distanceContinuousmonitoringMonitoringaccordingtoTechnicalspecificationsforwater(5-5)fortheinventoryyear4ElectricityconsumptionContinuedContinuousmonitoringTypesandconsumptionofintheinventoryyearmaterialsand/orchemicalsAmountsofmaterialsContinuousmonitoringtransportedandcorrespondingintheinventoryyeartransportationtypeandDailymonitoringinthedistanceWatervolumetreatedTurbidity,colorofrawwater112Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementAssociatedStageActivitydataaccountingDatarequirementsSources,referencespecificationsormethodsequationSuspendedsolidcontentofinventoryyearresources(Watervolume)monitoring(DB37/T3858-2020)sludgeTypesandamountsoffossil(6-1)MonitoringtheentireObtainedfromtheconstructioncompany’sledgerfuelconsumptiondemolitionperiodTypesandquantityofmachineMonitoringtheentireObtainedfromtheconstructioncompany’sledger(6-2)demolitionperiodshiftsAssetreplacementandPowerconsumption(6-3)MonitoringtheentireObtainedfromtheconstructioncompany’sledgerdemolitionperioddemolitionAmountsofbuildingwastetransportedandcorrespondingMonitoringtheentireObtainedfromtheconstructioncompany’sledger(6-4)demolitionperiodtransportationtypeanddistanceCarbonoffsetgeneratedfrom(6-5)MonitoringtheentireObtainedfromtheconstructioncompany’sledgerrecoveredmaterialsdemolitionperiod1.Whenitisdifficulttoobtainthedataofplanningandconstructionactivities,thedesignscaleortotalconstructioninvestmentcanbeusedtomakearoughestimationincombinationwiththechartinSection4.5.2.Theconstructionperiodreferstothewholedurationoftheplanningandconstructionprojectfromthestartoftheformalprojecttothetimewhenitisfullyputintoservice.3.Non-essentialdatacollected.Whenitisdifficulttoobtaintheexacttypesandconsumptionoffossilfuels,thisdatacanbeusedasanalternativemethod.4.Theelectricityconsumptionintheinventoryyearreferstothelevelafteroperationgettingstable.113Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable8.2Summaryofthesourceandacquisitionofdatarequiredforcarbonemissionaccountingofwastewatermanagementsystem.StageActivitydataAssociatedDatarequirementsSources,referencespecificationsPlanningandconstruction5accountingormethodsOperationandmaintenanceequationTypesandamountsoffossilfuelconsumption(4-1)MonitoringtheentireconstructionperiodObtainedfromtheconstructioncompany’sledger1Typesandquantityofmachineshifts2MonitoringtheentireconstructionObtainedfromtheconstruction(4-2)periodcompany’sledgerElectricityconsumption(4-3)MonitoringtheentireconstructionObtainedfromtheconstruction(4.4-1)Typesandamountsofconstructionmaterial(4.5-1)periodcompany’sledgerconsumptionAmountsofmaterialstransportedandMonitoringtheentireconstructionObtainedfromtheconstructioncorrespondingtransportationtypeanddistanceperiodcompany’sledgerMonitoringtheentireconstructionObtainedfromtheconstructionperiodcompany’sledgerElectricityconsumption(5-2)MonitoringfortheinventoryyearOperationledger/canbeobtainedbyMonitoringfortheinventoryyearreadingtheelectricitymeter,takingtheTypesandamountsofmaterialandchemicaldifferencebetweentheelectricitymeter(5-3)readingsattheendoftheyear(December31st)andthebeginningoftheyearconsumption(January1st).ItcanalsobebasedonthesettlementvoucherfromtheelectricitysupplydepartmentOperationledger/canbeobtainedaccordingtothestatisticalrecordsoftheContinued114Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementStageActivitydataAssociatedDatarequirementsSources,referencespecificationsaccountingormethodsAmountsofmaterialstransportedandcorrespondingtransportationtypeandequationwatersupplysystemoperatingunitsordistance(5-4)thepurchasecontractfromthesupplySewagesewerfacilitiesenterprises(5-10)InfluentvolumeandCODconcentrationof(5-12)Monitoringallseptictankswithin4timespermonthfortheinventoryseptictank(5-13)theorganizationalboundaryyear4/24hoursequalproportionmixed(5-14)-sampling/TechnicalspecificationsforThepopulationservedbytheseptictank3wastewatermonitoring(HJ91.1-2019)Diameter,slopeandlengthofwastewater(5-15~16)MonitoringallwastewatersewersDesigndatasewersandtheconveyedwastewater(5-18)withintheorganizationalboundaryDesigndata/monitoring4timespertemperatureandvolumemonthfortheinventoryyear//TechnicalMonitoringeachCSOeventinthespecificationsforwastewaterTheaverageorganicmatterandTNinventoryyearwithinthemonitoring”(HJ91.1-2019),“Methodsconcentrationofwastewaterinsewersorganizationalboundaryfortheexaminationofmunicipalsewage-(CJ/T51-2018)ThewatervolumeandCOD/TNconcentration(5-17)TechnicalspecificationsforwastewaterinCSOevent(5-20)monitoring(HJ91.1-2019)/MethodsfortheexaminationofmunicipalsewageTheworkingheadandefficiencyof(CJ/T51-2018)(5-3)DesigndatawastewaterliftingpumpWastewatertreatmentplantContinued115Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorStageActivitydataAssociatedDatarequirementsSources,referencespecificationsaccountingAveragemonitoringdataintheormethodsVolumeofwastewaterhandledinventoryyearBOD5/TNconcentrationininfluentandequationMonitoringeffluent(5-31~34)(5-AveragemonitoringdataintheHRT,watertemperature,MLVSS35~45)inventoryyearMethodsfortheexaminationofmunicipalconcentrationofbiologicaltreatmentunitssewage(CJ/T51-2018)Productionofwastesludge(5-21~30)VSSconcentrationofsludgebeforeandafterDeterminationmethodformunicipalanaerobicdigestion(5-21~23)sludgeinwastewatertreatmentplantVolumeofbiogasproduction(CJ/T221-2005)(5-35~36)(5-Dryweightofsludge40~41)Soil-Determinationoforganiccarbon-(5-35)Potassiumdichromateoxidation(5-40)spectrophotometricmethod(HJ615-(5-36)2011)(5-41)Soil-Determinationoforganiccarbon-(5-37~39)(5-Combustionoxidation-titrationmethod40~43)(HJ658-2013)Soil-Determinationoforganiccarbon-TOCofwastesludge(5-37~39)(5-42)CombustionoxidationnondispersiveContinued116Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementStageActivitydataAssociatedDatarequirementsSources,referencespecificationsaccountingormethodsequationinfraredabsorptionmethod(HJ695-2014)DOCofwastesludge(5-37~39)(5-42)-Theamountsofenergyexported(if(5-31~32)MonitoringfortheinventoryyearOperationledgerapplicable)(5-33)MonitoringfortheinventoryyearTheamountsofresourcesexported(ifapplicable)Typesandamountsoffossilfuelconsumption(6-1)MonitoringtheentiredemolitionObtainedfromtheconstructionperiodcompany’sledgerTypesandquantityofmachineshifts(6-2)MonitoringtheentiredemolitionObtainedfromtheconstructionperiodcompany’sledgerAssetreplacementandElectricityconsumption(6-3)MonitoringtheentiredemolitionObtainedfromtheconstructiondemolitionperiodcompany’sledgerAmountsofbuildingwastetransportedandMonitoringtheentiredemolitionObtainedfromtheconstructionperiodcompany’sledgercorrespondingtransportationtypeand(6-4)distanceTheamountsofbuildingwasterecycled(6-5)MonitoringtheentireconstructionObtainedfromtheconstructionperiodcompany’sledger1.Theconstructionperiodreferstothewholedurationoftheplanningandconstructionprojectfromthestartoftheformalprojecttothetimewhenitisfullyputintoservice.2.Non-essentialdatacollected.Whenitisdifficulttoobtaintheexacttypesandconsumptionoffossilfuels,thisdatacanbeusedasanalternativemethod.3.Non-essentialdata.Whenthedataofseptictankinfluentvolumeandwaterqualityarenotavailable,thisdatacanbeusedasanalternativemethod.4.Theelectricityconsumptionintheinventoryyearreferstothelevelafteroperationgettingstable.5.Whenitisdifficulttoobtainthedataofplanningandconstructionactivities,thedesignscaleortotalconstructioninvestmentcanbeusedtomakearoughestimationincombinationwiththechartinSection4.5.117Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable8.3Summaryofthesourceandacquisitionofdatarequiredforcarbonemissionaccountingofwaterreclamationsystem.StageActivitydataAssociatedDatarequirementsandSources,referencespecificationsoraccountingrecommendationsmethodsPlanningandTypesandamountsoffossilfuelconstruction5consumptionequationMonitoringtheentireconstructionObtainedfromtheconstructioncompany’sledgerTypesandquantityofmachine(4-1)periodOperationandshifts2(4-2)MonitoringtheentireconstructionObtainedfromtheconstructioncompany’sledgermaintenance(4-3)periodElectricityconsumptionMonitoringtheentireconstructionObtainedfromtheconstructioncompany’sledger(4-4)periodTypesandamountsofObtainedfromtheconstructioncompany’sledgerconstructionmaterial(4-5)MonitoringtheentireconstructionconsumptionperiodObtainedfromtheconstructioncompany’sledgerAmountsofmaterialstransportedandcorrespondingMonitoringtheentireconstructionOperationledger/canbeobtainedbyreadingthetransportationtypeanddistanceperiodelectricitymeter,takingthedifferencebetweentheelectricitymeterreadingsattheendoftheyearElectricityconsumption(5-2)Continuousmonitoringforthe(December31st)andthebeginningoftheyear(5-3)inventoryyear(January1st).ItcanalsobebasedonthesettlementvoucherfromtheelectricitysupplydepartmentTypesandamountsofmaterial(5-4)ContinuousmonitoringfortheOperationledger/canbeobtainedaccordingtotheandchemicalconsumptioninventoryyearstatisticalrecordsofthewatersupplysystemoperatingunitsorthepurchasecontractfromtheAmountsofmaterialsand(5-5)ContinuousmonitoringforthesupplyenterpriseschemicalstransportedandinventoryyearOperationledger/canbeobtainedaccordingtothestatisticalrecordsofthewatersupplysystemContinued118Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementStageActivitydataAssociatedDatarequirementsandSources,referencespecificationsoraccountingrecommendationsmethodsequationcorrespondingtransportationoperatingunitsorthepurchasecontractfromthetypeanddistancesupplyenterprisesWatervolumetreatedContinuousmonitoringfortheMonitoring/Technicalspecificationsforwaterinventoryyearresources(Watervolume)monitoring(DB37/T3858-2020)Typesandamountsoffossilfuel(6-1)MonitoringtheentireconstructionObtainedfromtheconstructioncompany’sledgerconsumption(6-2)periodObtainedfromtheconstructioncompany’sledgerTypesandquantityofmachineMonitoringtheentireconstructionshiftsperiodAssetreplacementElectricityconsumption(6-3)MonitoringtheentireconstructionObtainedfromtheconstructioncompany’sledgeranddemolitionperiodObtainedfromtheconstructioncompany’sledgerAmountsofbuildingwastetransportedandcorresponding(6-4)MonitoringtheentireconstructiontransportationtypeanddistanceperiodCarbonoffsetgeneratedfrom(6-5)MonitoringtheentireconstructionObtainedfromtheconstructioncompany’sledgerrecoveredmaterialsperiod1.Theconstructionperiodreferstothewholedurationoftheplanningandconstructionprojectfromthestartoftheformalprojecttothetimewhenitisfullyputintoservice.2.Non-essentialdatacollected.Whenitisdifficulttoobtaintheexacttypesandconsumptionoffossilfuels,thisdatacanbeusedasanalternativemethod.3.Theelectricityconsumptionintheinventoryyearreferstothelevelafteroperationgettingstable.4.Whenitisdifficulttoobtainthedataofplanningandconstructionactivities,thedesignscaleortotalconstructioninvestmentcanbeusedtomakearoughestimationincombinationwiththechartinSection4.5.119Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable8.4Summaryofstatisticalandmonitoringdatarequiredforcarbonemissionaccountingofrainwatermanagementsectors.StageActivitydataAssociatedDatarequirementsandSources,referencespecificationsaccountingrecommendationsormethodsPlanningandTypesandamountsoffossilconstruction5fuelconsumptionequationMonitoringtheentireconstructionperiodObtainedfromtheconstructionTypesandquantityofmachine(4-1)Monitoringtheentireconstructionperiodcompany’sledgerOperationandshifts2MonitoringtheentireconstructionperiodObtainedfromtheconstructionmaintenance(4-2)company’sledgerMonitoringtheentireconstructionperiodObtainedfromtheconstructionElectricityconsumption(4-3)company’sledgerTypesandamountsof(4-4)Obtainedfromtheconstructionconstructionmaterialcompany’sledgerconsumption(4-5)Amountsofmaterials(5-1)MonitoringtheentireconstructionperiodObtainedfromtheconstructiontransportedandcorresponding(5-46~48)Monitoringtheentireconstructionperiodcompany’sledgertransportationtypeanddistanceTypesandamountsoffossilContinuousmonitoringfor1calendaryear3Obtainedfromtheconstructionfuelconsumptioncompany’sledgerOperationledgercanbeobtainedbyElectricityconsumption(5-2~3)readingtheelectricitymeter,takingthe(5-49~51)differencebetweentheelectricitymeterreadingsattheendoftheyear(December31st)andthebeginningoftheyear(January1st).ItcanalsobebasedonthesettlementvoucherfromtheelectricitysupplydepartmentContinued120Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementStageActivitydataAssociatedDatarequirementsandSources,referencespecificationsaccountingrecommendationsormethodsAssetreplacementVegetationcoveringareaofanddemolitiongreenfacilitiesequationThewholeoperationandmaintenancestageObtainedbyqueryingthevegetationRainwatercontrollingfacilitiescarbonsequestrationcoefficient(5.6.2-7)InfluentCOD/TNconcentrationContinuousmonitoringofCOD,TNandotherObtainedfromtheconstruction(5-53~55)dataintherainwaterenteringthewetlandforcompany’sledgertheinventoryyearenteringtowetlandMonitoringtheentiredemolitionperiodObtainedfromtheconstructioncompany’sledgerTypesandamountsoffossil(6-1)MonitoringtheentiredemolitionperiodObtainedfromtheconstructionfuelconsumption(6-2)company’sledgerTypesandquantityofmachineMonitoringtheentiredemolitionperiodObtainedfromtheconstructionshiftscompany’sledgerElectricityconsumption(6-3)Amountsofbuildingwaste(6-4)MonitoringtheentiredemolitionperiodObtainedfromtheconstructiontransportedandcorrespondingcompany’sledgertransportationtypeanddistanceTheamountsofrecoveredand(6-5)MonitoringtheentiredemolitionperiodObtainedfromtheconstructionexportedmaterialscompany’sledger1.Theconstructionperiodreferstothewholedurationoftheplanningandconstructionprojectfromthestartoftheformalprojecttothetimewhenitisfullyputintoservice.2.Non-essentialdatacollected.Whenitisdifficulttoobtaintheexacttypesandconsumptionoffossilfuels,thisdatacanbeusedasanalternativemethod.3.Theelectricityconsumptionintheinventoryyearreferstothelevelafteroperationgettingstable.4.Whenitisdifficulttoobtainthedataofplanningandconstructionactivities,thedesignscaleortotalconstructioninvestmentcanbeusedtomakearoughestimationincombinationwiththechartinSection4.5.121Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector8.3EMISSIONFACTORSACQUISITION8.3.1GeneralemissionfactorsTheemissionfactorsrequiredforcarbonaccountingofurbanwatersectorscanberoughlydividedintotwocategories,namely,indirectemissionfactorsanddirectemissionfactors.Theindirectemissionfactorsaremainlyusedtoaccountforemissionactivities,includingelectricityconsumptionandmaterialconsumption.Theydependontheoptimizationandprogressofsocialenergystructuresandindustriallevels,respectively,andarenotcontrolledbyurbanwatersectors.Theyaremainlycalculatedandupdatedbyothersectorsandaresuitableforeachsystemofurbanwatersector.Therefore,theyarealsocalledgeneralemissionfactorsofwhichthevalues,sourcesandupdatingmethodsusedinthisGuidelinesaresummarizedinTable8.5.Table8.5Summaryofgeneralemissionfactorsandtheirsources.SystemsTargetedSourcesLinksNotesGeneralactivitiesAppendixB.1FossilfuelsThePeople’sRepublicofChinaAppendixB.2OfficialnationalgreenhousegasAppendixB.3websitesElectricityinventory(NDRCofChina,AppendixB.4Buildingmaterials2007)DatalacksTransportationProvincialgreenhousegasAppendixB.5updatesandinventoryguidelines(trial)maynotChemicalsChinaenergystatisticalmatchtheyearbook2011(NationalcurrentBureauofStatistics,2011)situationMinistryofEcologyandwellEnvironmentofthePeople'sContinuedRepublicofChina,2020Standardforbuildingcarbonemissioncalculation(GB/T51366-2019)(MHURDofChina,2019)Standardforbuildingcarbonemissioncalculation(GB/T51366-2019)(MHURDofChina,2019)Winnipeg.(2012)EmissionfactorsinkgCO2-equivalentperunit.AlexisA.(2021)CarbonFootprintofFinnishWastewaterTreatmentPlants.Finland:AaltoUniversity.JohnstonAHandKaranfilT.(2013).Calculatingthe122Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementSystemsTargetedSourcesLinksNotesactivities-WatergreenhousegasemissionsofAppendixB.8-supplyCarbonwaterutilities.Journal-AppendixC.1systemsequestrationbyAmericanWaterWorksAppendixC.2vegetationAssociation,105(7),E363-AppendixC.3Waste-E371.AppendixC.4waterConstructionofIncopa.(2014)LifeCyclemanage-watertreatmentAnalysisofLeadingmentplantsCoagulants:ExecutivesystemConstructionofSummary.Karlsruhe:.Storm-waterdistributionIPCC.(2006)Emissionfactorwaternetworksdatabase.systemConstructionofCLCD.(2011)ChineseLifewastewatersewerCycleDatabase.CuiPengfei.(2019)ResearchonConstructionofstagedemissionreductionwastewaterstrategyofconstructionindustrytreatmentplantsbasedonmeasurementoflifeConstructionofcyclecarbonemissions.TaiyuanstormwaterUniversityofTechnology.systemPreparedbyanalyzing12waterConstructiontreatmentplantprojectswithinformationvarioustreatmentcapacityandprocesses.Preparedbyanalyzing18waterdistributionnetworkprojectswithvariousdimetersandmaterials.Preparedbyanalyzing32wastewatersewerprojectswithvariousdiameterandmaterials.Preparedbyanalyzing20wastewatertreatmentplantprojectswithvarioustreatmentcapacity,processes,andeffluentstandards.AppendixC.5123Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector8.3.2CH4andN2OemissionfactorsinwastewatermanagementsystemsSomeofthewastewatermanagementfacilitiesproduceandemitCH4andN2Oduetothebiochemicalprocessesoforganicandnitrogencompoundsinwastewater.Ingeneral,theaccountingmethodsofCH4andN2Oemissionsaremostlybasedonemissionfactorswhicharedeterminedinadvanceandalsocloselyrelatedtotheprocesstype,managementandoperationlevel,andregionalclimate.Currently,therearenouniformvaluesforCH4andN2Oemissionfactorsgloballyduetotheirfluctuationsanduncertainty.IPCCrecommendedtypicalvaluesforCH4andN2Oemissionfactorsintheirreportbyreviewingliteraturewhichisusuallyadoptedincarbonaccountingpractices.Besides,afewcountrieshavealsoformulatedtheirowncountry-specificemissionfactors.Forexample,NewZealandpublishedacarbonaccountingguidelineforwastewatertreatmentin2021inwhichtheemissionfactorsofCH4andN2Oweremodified.Inaddition,Australia,Denmark,andtheUnitedKingdomalsohavetheirownspecificemissionfactors.InviewofthefactthatmonitoringworksandinformationaboutCH4andN2OemissionfactorsinwastewatermanagementsystemsinChinaarelimited,thisGuidelinespresentsupdatedemissionfactorsbyreferringtoliteraturebasedonIPCC’soriginaldata,whicharesummarizedinTable8.6.Inaddition,thisGuidelinessummarizesthemonitoringmethodsfordeterminingemissionfactorsinwastewatermanagementsystems.Withsufficientlocalmonitoringresults,country-specificemissionfactorsforChinacanbeobtained.124Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementTable8.6SummaryofsourcesofCH4andN2Oemissionfactorsinwastewatermanagementsystem.ModulesFacilitiesSourcesLinksNotesInternationalWaterSepticAssociationEvaluationSection5.3.2On-sitetestingCH4ofGreenhouseGasresultsaretheEmissionsfromSepticTable5.4mostaccurate,tankSystemsTable5.5andlocal2019RefinementtothemonitoringworkCH42006IPCCGuidelinessamplesareforNationalGreenhouselimited.SewageWaste-GasInventoriessewerwater(IPCC,2019)Thewaterfacilitiesdrain-2019Refinementtothequalityoftheage2006IPCCGuidelinesreceivingwaterforNationalGreenhousebodyshouldbeN2OGasInventoriestakeninto(IPCC,2019)accountwhenCH4TemperatureandcarryingoutCSOOrganicLoadingDependencyofMethaneN2OandCarbonDioxideEmissionRatesofaFull-ScaleAnaerobicWasteStabilizationPondDOI:10.1016/0043-1354(94)00251-2IPCCGuidelinesforNationalGreenhouseGasInventoriesMunicipalSewerNetworksasSourcesofNitrousOxide,MethaneandHydrogenSulphideEmissions:AReviewandCaseStudiesDOI:10.1016/j.jece.2015.07.006.2019Refinementtothe2006IPCCGuidelinesforNationalGreenhouseGasInventories(IPCC,2019)Continued125Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorModulesFacilitiesSourcesLinksNotesAppendixB.6actualCH4TwotypesofemissionAppendixB.7monitoringtofactors,internationalandSection5.3.3determinetheWastewaterWaste-domestic,areprovidedemissionfactorstreatmentwaterrespectively,whichareplantstreat-derivedfromtheCH4andN2Omentcollationofliteratureemissionsplantsdata.Thisguidelineismonitoringbasedonthe2019worksinactualN2ORefinementtothe2006wastewaterIPCCGuidelinesfortreatmentplantsSludgedisposalNationalGreenhousearerare,andGasInventoriesthereisacorrecting14piecesofsignificantdata,extending18piecesvariationinofdatatoupdatetheemissionsemissionfactorsbetweenTwotypesofemissiondifferentfactors,internationalandwastewaterdomestic,areprovidedtreatmentplants.respectively,whichareWhentherearederivedfromtheenoughsamples,collationofliteraturetheemissiondata.Thisguidelineisfactorsthatarebasedonthe2019moresuitableRefinementtothe2006forChina'sIPCCGuidelinesforwastewaterNationalGreenhousetreatmentplantsGasInventoriescanbesortedcorrecting30piecesofout.Thedata,extending46piecesmonitoringandofdatatoupdatethedeterminationemissionfactorsmethodsaresummarizedin2019Refinementtothethearticle.2006IPCCGuidelinesforNationalGreenhouseOn-sitetestingGasInventoriesresultsarethemostaccurate,andlocalmonitoringworksamplesarelimited.126Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagementItisworthnotingthat,withregardtothecalculationofCH4emissionsfromwastewatertreatmentplants,thisGuidelinesmodifiedtheequationsrecommendedbytheIPCCtomatchcurrentemissionfactorsEquation(5.25).Inotherwords,theactivitydataofEquation(5.25)isinfluentBOD5insteadofBOD5removed.However,itshouldbenotedthattheaccountingequationsprovidedbyIPCCismorescientific.Ifthecorrespondingemissionfactorisavailable,IPCC’sequationisrecommendedandaccurate.Therefore,themonitoringanddeterminationofCH4emissionfactorsinwastewatertreatmentplantsshouldbeconsistentwiththeequationsadopted.IntermsofthecalculationofN2Oemissions,therearetwoaccountingmethodsavailableinwhichtheactivitydataisinfluentTNandTNremoval,respectively.Thesetwomethodshavetheirownadvantagesanddisadvantages,asdiscussedindetailbydeHassetal.(2022).Inaddition,studiesshownthatN2OemissionintensityisassociatedwiththeTNremovalefficiency.Therefore,adynamicemissionfactorbyconsideringthiscorrelationissuggestedasafocusoffutureresearch.Overall,on-sitemonitoringshouldberecommendedandshouldbepromotedinordertoensuretheaccuracyofcarbonaccountingand/orformulateamorerepresentativelocalemissionfactor.Ifthemonitoringresultsareusedtoobtainemissionfactor,somesuggestionsarelistedtoguidethemonitoringpractices.•Themonitoringshouldbeconductedinfull-scalecentralizedWWTPsthatprimarilyreceivemunicipalwastewaterordomesticwastewater.•CH4/N2OemissionmonitoringsitesshouldcoverallfacilitiesthatmaygenerateCH4/N2OintheWWTPs,includingpumpingstations,gritchambers,sedimentationtanks,biologicaltanks,sludgestoragetanks,sludgethickeninganddewateringrooms,mudcakestackingareas(ifsludgeistransportedoutoftheplanttimely,itmaynotbeconsidered),etc.,butdoesnotincludeanaerobicdigestiontanks.•Themonitoringactivityshouldlastforaninventoryyear.Currently,themostcommonlyusedmethodsformonitoringCH4/N2OemissionsinWWTPsincludethefluxchambermethodandthetracergasdispersionmethod.Theprinciples,equipment,andimplementationproceduresofthesetwomethodscanbefoundinpublishedarticles.Inaddition,forWWTPsortreatmentunitswithenclosedcovers,itisrecommendedthatoffgasvolumeandCH4/N2Oconcentrationshouldbemonitoredtodetermineemissionintensity.ThisGuidelinesalsosummarizestherequirementsandapplicablescenarioofvariousmethodsinTable8.7,andthecalculationofCH4/N2OemissionfactorscanbedoneusingEquation(8.1)to(8.8).127Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTable8.7SummaryofmonitoringrequirementsofvariousmethodsforCH4andN2OemissionfactorsinWWTPs.MethodsScenarioGasmonitoringWaterqualityNotesDatadataThemostNon-aeratedcommonlyfacilityFluxchamberInfluentandusedmethod,volumeV,coverageeffluentvolumeQ,differentFluxchamberareaA,facilityareaBOD5andTNfacilityunitsmethodAt,targetgasconcentration,candetermineconcentrationinaoutboundsludgethenumberofAerationfacilitycertaintimeintervalvolumeW,VSSmonitoringintheboxCconcentrationsitesTracergasInfluentandaccordingtoGasfluxM,effluentvolumeQ,thedissolveddispersion\coverageareaA,BOD5andTNoxygentargetgasconcentration,concentrationmethodconcentrationintheoutboundsludgeorORPboxaftermonitoringvolumeW,VSSClosedCconcentrationCommonlywastewaterusesContinuousInfluentandacetyleneas\measurementofeffluentvolumeQ,tracergastreatmenttracergasandtargetBOD5andTNplantsgasconcentrationsatconcentration,\thedownwindoutletoutboundsludgeCtr/Ctg,backgroundvolumeW,VSSconcentration(tracerconcentrationgasandtargetgasintheatmosphere)Ctr-Influentandb/Ctg-b,tracergaseffluentvolumeQ,releaserateQtrBOD5andTNconcentration,TailgasemissionM,outboundsludgetargetgasvolumeW,VSSconcentrationintailconcentrationgasC𝐸𝑔=∑(𝑉/𝐴)𝜌(𝑑𝐶/𝑑𝑡)∙𝐴𝑡(8.1)𝐸𝑔=∑(𝑀𝜌𝐶/𝐴)∙𝐴𝑡(8.2)128Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDataacquisitionandmanagement∫(𝐶𝑡𝑔−𝐶𝑡𝑔−𝑏)𝑑𝑥∙𝑀𝑊𝑡𝑔𝐸𝑔=𝑄𝑡𝑟∙∫(𝐶−𝐶)𝑑𝑥∙𝑀𝑊(8.3)𝑡𝑟𝑡𝑟−𝑏𝑡𝑟𝐸𝑔=M∙𝐶(8.4)𝐸𝐶𝐻4−1=𝐸𝑔/(𝑄∙𝐵𝑂𝐷𝑖𝑛)(8.5)𝐸𝐶𝐻4−2=𝐸𝑔/(𝑄∙𝐵𝑂𝐷𝑖𝑛−𝑄∙𝐵𝑂𝐷𝑒𝑓𝑓−𝑊∙𝑉𝑆𝑆∙𝐾𝐵𝑂𝐷)(8.6)𝐸𝑁2𝑂−1=𝐸𝑔/(𝑄∙𝑇𝑁𝑖𝑛)(8.7)𝐸𝑁2𝑂−2=𝐸𝑔/(𝑄∙𝑇𝑁𝑖𝑛−𝑄∙𝑇𝑁𝑒𝑓𝑓−𝑊∙𝑉𝑆𝑆∙𝐾𝑁)(8.8)Where:𝐸𝑔—Thetargetgasemissionofthewastewatertreatmentplantforacertainperiodoftime𝐸𝐶𝐻4−1/𝐸𝑁2𝑂−1—EmissionfactorsbasedoninfluentBOD5orTNloading(applicabletothisguideline)𝐸𝐶𝐻4−2/𝐸𝑁2𝑂−2—EmissionfactorsbasedonBOD5orTNremovalload𝜌—Thedensityofthetargetgasatthecorrespondingtemperature𝑀𝑊𝑡𝑔/𝑀𝑊𝑡𝑟—Relativemolecularmassoftargetgasandtracergas𝐾𝐵𝑂𝐷—Equivalentofsludge𝐾𝑁—Nequivalentofsludge129Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestChapter9Resultinterpretationandreporting9.1RESULTINTERPRETATIONThepurposeofcarbonemissionaccountingistoserveasatoolforguidingtheplanning,implementation,andachievementofcarbonemissionreductionforurbanwatersectors.Therearetwotimepointsinthelifecycleofurbanwatersectortofulfillcarbonemissionreduction,i.e.,theplanningandconstructionstageandoperationandmaintenancestage.Fortheexistingfacilitiesofurbanwatersectorsunderservice,intheoperationandmaintenancestageisthefocus.Asstatedabove,watercompanies,watersectorassociations,andwaterauthoritieshavetheirspecificrolesinpromotingthecarbonaccountingandcarbonemissionreductionofurbanwatersector.Tomakebetteruseofthecarbonaccountingresults,thisGuidelinesbrieflyprovidesometipsforinterpretingandanalyzingtheresults,facilitatingtheformulationofpolicyandregulations,guidingtheroleofdifferententitiesincarbonemissionreduction(Figure9.1).Overall,watercompany,watersectorassociation,andwaterauthorityshouldtaketheirexclusiveroleassummarized:•Watercompany:Basedontheaccountingresults,watercompanyanalyzesandidentifiesthecontributionofeachemissionactivityandthekeyactivities,thenformulatetheplanandtheclusterofstrategiesforcarbonreduction.Regularquantificationofthecarbonemissionistoprovidefeedbackontheefficiencyandadjustmentsofemissionreductionmeasures.•Watersectorassociation:Watersectorassociationhastheadvantagesoflinkswithmorewatercompaniesandaccountingresults.Thus,theycouldguidewatercompaniestoimplementcarbonreductioninamoresystematicpathwaybyestablishabenchmarkevaluationsystemandasectoraveragecarbonemissionlevel.Besides,theycanalsocollectandcompileaworkbookofefficientreductiontechnologiesandroadmapstoprovidedirectionforwatercompaniestocarryoutcarbonemissionreductionpractices.•Waterauthority:Waterauthoritiesmainlytaketheresponsibilityofpolicyandregulationestablishmenttohelpwatercompaniesimplementcarbonreductionmoreactively,scientifically,andeconomically.Forexample,waterauthoritiesshouldactivelydiscusswithothergovernmentsectorstopromotetheacceptanceofresourcesfromwastewaterwhichwillundoubtedlypromotetherecoveryenthusiasmofwatercompanies.Besides,waterauthoritiescanalsopromotethewatersectorsinbeincludedincarbontradingmarket,therebyenhancingthemotivationofwatercompaniestoimplementcarbonreduction.Additionally,relevanttaxreductionandsubsidypoliciesshouldbeformulatedtoguideandsupportthetransformationoflow-carbondevelopment.131Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure9.1Therolesandrelationshipamongdifferententitieswithintheurbanwatersectorsintheanalysisofcarbonemissionaccountingresults.Basedontheresultsofcarbonemissionaccountingresultsofurbanwatersectors,thissectionputsforwardseveralfeasibleanalysisideasandmethodsforreference,aimingatcondensingandsublimatingthekeylinkshiddenundertheaccountingresults,andassistingentitiestoformulateeffectivecarbonemissionreductionstrategies,helpingpromotethenovelcarbonemissionreductiontechnologiesandpolicies.9.1.1KeyinformationanalyzedTheanalysisofcarbonaccountingresultsthatcanbeconductedaccordingtoTable9.1.Table9.1Summaryofthekeyinformationextractedfromtheaccountingresults.EntityAnalysisDataToolsinformationParetoEstablishthebaselinediagram/CharacteristicdiagramIdentifykeycarbonCarbonemissionParetodiagramemissionactivitiesaccountingresultsParetodiagramPredictthefuturetrendWatercompanySummarizethelow-carbonoperationScatterdiagramparametersCarbonemissionCarbonemissionaccountingresultsHistogramcomparisonfromvariousprojectsContinued132Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestResultinterpretationandreportingEntityAnalysisDataToolsWatersectorinformation-associationCarbonemissionCarbonemissionaccountingresults-WaterauthorityintensityandbenchmarkingofwatercompaniesRelationshipbetweenAccountingresultscarbonemissionandofallorpolicyrepresentativeoperatingenterprisesandindustryassociationsinthejurisdictionoraccountingresultsofsimilarcities9.1.2Analyzingmethodologies9.1.2.1ParetodiagramTheParetodiagram(Figure9.2)aimstoidentifythemostsignificantcarbonemissionactivitiestoaddresstheissuemosteffectively.Byrankingthecarbonemissions(intensity)ofallactivities,theemissionactivitiesareclassifiedintomajoractivities,minoractivities,andgeneralactivities.Themajoractivitiesaretheprimarytargetsonwhichcarbonreductionmeasuresshouldbeprioritized.Itiseasierandmoreeffectivetoreducethecarbonemissions(intensity)focusingonmajoractivitiesinsteadoftheminororgeneralfactorsattheverybeginning.ByanalyzingtheresultsoftheParetodiagram,emissionreductionstrategiescanbedeveloped.ThestepstousetheParetodiagramareasfollows:•Collatetherequireddataofcarbonaccountingresults.•Arrangecarbonemissions(intensity)dataindescendingorderbasedonemissionintensityandcalculatethecumulativeemissionratio.•Plotthediagramwithemissionactivitiesonthehorizontalaxis,carbonemissions(intensity)ontheleftverticalaxis,andcumulativeemissions(intensity)ratioontherightverticalaxis.•Dividetheemissionactivitiesinthe0%~80%rangebasedonthecumulativeratiointomajoractivities.Dividetheemissionactivitiesinthe80%~90%rangeintominoractivities.Dividetheemissionactivitiesinthe90%~100%rangeintogeneralactivities.133Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure9.2Paretodiagramindicatingcarbonemissions(intensity).9.1.2.2CharacteristicdiagramThecharacteristicdiagram,alsoknownasthefishbonediagram(Figure9.3),isamethodtoanalyzeandfindoutthekeyreasonsforacertainproblem.Thecharacteristicfactordiagramcanbeusedtofindoutthemajorinfluencingfactorsaffectingthetargetemissionactivitiesthroughanalysis,soastoaccuratelyadoptcorrespondingemissionreductiontechnologiesandmeasures.Thestepstousethecharacteristicdiagramareasfollows:•Takingthekeyfactorsinfluencingthetargetedcarbonemissionasthemainreasonand“mainbone”whichisrepresentedbyahorizontalline.•Dissectandlistthesecond-levelfactorsthatmayaffectthemainreason,anddrawthecorresponding“middlebone”onthe“mainbone”.•Dissectandlistthethird-levelfactorsthatmayaffectthesecond-levelfactors,anddrawthecorresponding“smallbones”onthe“middlebone”.Iftherearefurthersubfactors,itcanbededucedinthiswayuntiltheanalysisreachesthelevelwherecorrespondingemissionreductionmeasurescanbetaken.•Accordingtotheimportanceofinfluencingfactorsateachlevel,thefactorsthatareconsideredtohaveasignificantimpactoncarbonemissions(intensity)aremarked.134Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestResultinterpretationandreportingFigure9.3Primaryandsecondaryfishbonediagramofcarbonemissions.9.1.2.3HistogramForunitsusingthesametreatmentprocessandoperatingmode,thecarbonemissionlevelscannotbethesame,butalwaysfluctuatewithinacertainrange.Thehistogramcanbeusedtoshowitsstatisticalregularity,presentthedesignandoperationleveldistribution,andevenestimatethecarbonemissionlevelofthelargergroup(Figure9.4).Thestepstousethehistogramareasfollows:•Collatethecarbonemissions(intensity)dataofmanyfacilities(numberisn)usingthesametreatmentprocessand/oroperatingmode.•Identifythefacilitywiththemaximum(Max)andminimum(Min)emissions(intensity).Calculatethenumberofgroups:k=√n,theclassinterval:h=(max−min)/k(theresultistakenasaninteger).•Dividethecarbonemissionintensitydataintogroupsbasedoninterval.Thefirstgroupwillincludedatarangingfrommin~min+h,thesecondgroupwillincludedatarangingfrommin+k~min+2k,andsoon,untilthelastgroupincludesdatarangingfrommax-h~max.Allthedatashouldbeassignedtotheirrespectivegroups.•Calculatethenumbersofdataineachgroup.•Drawthehistogramwitheachcarbonemissions(intensity)datagroupasthehorizontalaxisandthenumberofdataineachgroupastheverticalaxis.•Analyzetheshapeofthehistogram.Whenthegraphshowsapeakshapetotheleft,itindicatesthattheoveralloperationleveloftheprocessisrelativelyhighandthecarbonemissionsislow.Whenthegraphappearstobepeak-shapedtotheright,itisreversed.•Performhistogramanalysisonmultipletreatmentprocessesandoperatingmodes,comparingthecarbonemissionlevelsandtechnologicalmaturitybetweendifferentprocesses.Basedonthisanalysis,providerecommendationsforpromotingandadoptinglower-carbonoperatingprocesses.135Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigure9.4Histogramindicatingcarbonemissions(intensity).9.1.2.4CorrelationscatterdiagramDuringtheoperationoftheurbanwatersectors,theremaybesomeunknowncorrelationsbetweensomeinfluencingfactorsandcarbonemissions(intensity).Thecorrelativerelationshipcanbedisplayedthroughthescatterdiagramanalysisprocess(Figure9.5),soastopredictandfindoutthemostsuitablelow-carbonoperatingparameters.Thestepstousethescatterdiagramareasfollows:•Identifyinfluencingfactorsrelatedtocarbonemissions(intensity).•Collatedataoncarbonemissions(intensity)andinfluencingfactors.•Takethedataofinfluencingfactorsasthehorizontalaxisandthecarbonemissions(intensity)astheverticalaxistodraweachdatapoint.•Analyzethecorrelogramtofindthecorrelationsinit.Figure9.5Scatterdiagramindicatingcarbonemissions(intensity).136Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestResultinterpretationandreporting9.2REPORTINGPROTOCOLThereportformatshouldrefertoAppendixG,andthereportingcontentshouldincludethefollowinginformation.9.2.1InformationofreportingentityThereportingentityshouldbetherelevantenterpriseorunitresponsibleforoperatingtheaccountingobject.Thereportshouldincludethenameandthenatureoftheentity,inventoryyear,industrysector,unifiedsocialcreditcode,legalrepresentative,accountingmanager,andcontactinformation.Detailedinformationshouldbeprovidedontheprocessflow,divisionofaccountingunitsandemissionsources.Tablesorgraphscanbeusedifnecessary.9.2.2DatasourcesThereportingentityshouldreportthevariousdatasourcerequiredfortheaccountingprocessaccordingtotheidentificationoftheemissionactivities.Forthedataofindirectemissionactivities,effortsshouldbemadetodifferentiatethecarbonemissiongeneratedbyvariousactivitiesandfunctions,soastoenhancethecomparabilityoftheaccountingresults.Thedatasourcesorcredentials,acquisitionormonitoringmethods,recordingfrequencyandotherdatashouldbespecified.9.2.3EmissionfactorsThereportingentityshouldreporttheemissionfactorsorothernecessarycalculationparameterscorrespondingtoeachdataset,andexplaintheirdatasources,referencesources,relevantassumptionsandreasons,etc.9.2.4CarbonemissionsThereportingentityshoulddescribekeyinformationsuchasaccountingboundariesandemissionactivities.Then,theemissionsofeachactivitiesshouldbereported,alongwiththecarbonemissionsofelectricityorheatconsumedbyeachactivities/function,thecarbonemissionsofmaterialsconsumedbyeachactivities/function,theamountofoutputcarboncompensation,etc.Finally,thetotalcarbonemissionsduringtheaccountingperiodispresented.137Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixATermsandsymbolsGreenhousegasThenaturallyoranthropogenicgasesintheatmospherethatabsorbandre-emitinfraredradiation.AccordingtothecategorizationofIPCC(IPCC,2006),thereare7majorgreenhousegases:carbondioxide(CO2),methane(CH4),nitrousoxide(N2O),hydrofluorocarbons(HFCs),perfluorocarbons(PFCs),sulfurhexafluoride(SF6)andnitrogentrifluoride(NF3).CO2,CH4andN2Oareprimarilyconsideredinthisguideline.CarbonemissionfromurbanwatersectorThetotalgreenhousegasemissions,expressedinCO2equivalent,resultingfromvariousactivitiesrelatedtourbanwatersector(includingwatersupplysystem,wastewatermanagementsystem,waterreclamationsystemandstormwatersystem)inplanning&construction,operation&maintenance,andassetreplacement&demolition.ReportingboundaryToavoidduplicationsoromissions,theidentifiedanddeterminedcollectionofallcarbonemissionactivitiesassociatedwiththeaccountingsystemwhichisthefocus.EmissionactivityAllunitsandprocessesdirectlyorindirectlyassociatedwiththeaccountingsystemthatresultingreenhousegasemissions,suchaselectricenergyconsumption,chemicalsconsumptionandbiologicalwastewatertreatment.CarbonemissionintensityThetotalcarbonemissionsgeneratedbytheaccountingentityduringtheproductionof1unitofproduct.DirectcarbonemissionTheGHGemissiongeneratedfromthesourcesownedorcontrolledbytheorganization.IndirectcarbonemissionTheGHGemissionsthatisaconsequenceofanorganization’soperationsandactivities,butthatarisesfromGHGsourcesthatarenotownedorcontrolledbytheorganization.139Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorGlobalwarmingpotential(GWP)Index,basedonradiativepropertiesofGHGs,relativetothatofCO2.CarbondioxideequivalentAcommonunitforcomparingtheradiativeforcingofaGHGtothatCO2,whichcanbewrittenasCO2-eq.ActivitydataQuantitativemeasureofactivitythatresultsinaGHGemissionorGHGremoval.CarbonemissionfactorThecoefficientrepresentstheemissionsofgreenhousegasesassociatedwithactivities.CarbonreductionTheactivitiesinwhichenterprisesreducetheintensityofgreenhousegasemissions,andthusdecreasethetotalcarbonemissions,throughtechnologicaladjustments,processoptimization,andothermeans.RenewablealternativestocarbonTheactivityinwhichenterprisesreducetheirtotalcarbonemissionsduringtheproductionprocessbyreplacingfossilfuelswithcleanenergy.CarbonsinkTheresourcesorenergyproducedintheproductionprocessoftheenterprisecanbeexportedexternally,i.e.,creatingthecorrespondingcarbonsink.EmissionpointThelocationsandprocesseswithinwatersectorfacilitiesandstructuresthatcontributetogreenhousegasemissions.Assetreset&demolitionTheprocessofrecycling,renewing,orrepurposingwatersectorfacilitiesorstructurestoreintroducethemforusewhentheyreachtheendoftheirlifecycle.GrayinfrastructureConventionalmunicipalinfrastructureconstructedbyhumans,suchasdams,pipelines,channels,etc.Itsbasicfunctionistorealizethedischarge,transferandtreatmentofwaterandpollutantsincities.GreeninfrastructureMunicipalinfrastructureconstructedutilizingnaturalspeciesandtheenvironment.Itsbasicfunctionistoregulatethewaterqualityandquantityinthecities,andenhancetheresilienceofcitiesagainstextremeevents.140Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestTermsandsymbolsUnitsymbola——yearL——literCelsiusm——meter℃——personmg——milligrammm——millimeterca——daymol——molegramMWh——megawatt-hourd——gigajoulem2——squaremeterhectarem3——cubicmeterg——joules——secondkilogramt——tonneGJ——kilometerkilowatt-hourhm2——J——kg——km——kWh——141Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixBEmissionfactorsB.1FOSSILFUELEMISSIONFACTORSTableB.1Summaryofemissionfactorsandcarbonoxidationratesbydifferentfossilfuel.EmissionfactorFossilfuelkgCO2/kg(solidandCarbonoxidationliquidfuel)/kgCO2ratekgCO2/GJ/m3(gaseousfuel)Anthracite98.081.9797.3%Generalbituminouscoal93.111.8697.0%Lignite98.562.0696%Washedcoal89.412.4596%Othercoalwashing89.410.7896%Coalproducts110.881.1790%Coke100.252.8593%Cokeovengas49.370.0008999%Othergas44.290.0001799%Crude72.233.0298%Fueloil75.823.1798%Gasoline67.912.9298%Dieselfuel72.593.1098%Jetkerosene70.073.0398%Generalkerosene70.433.0398%Liquefiedpetroleumgas61.813.1098%RefineryDryGas65.403.0498%Naphtha71.873.2698%Petroleumcoke98.824.1498%Otheroil71.873.2698%Naturalgas55.540.002299%1.ThedataofanthraciteandgeneralbituminouscoalcomefromResearchonChina'sGreenhouseGasInventory(NDRCofChina,2007)andGuidelinesforProvincialGreenhouseGasInventory(Trial)(NDRCofChina,2011).143Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector2.Thedataofwashedcleancoal,otherwashedcoal,andothergascomefromChinaEnergyStatisticalYearbook2011(NationalBureauofStatistics,2011),thedataofpetroleumcokeandotheroilproductscomefromEnergyUtilizationStatusofTenThousandEnterprises.B.2ELECTRICITYEMISSIONFACTORSOFCHINATableB.2SummaryofelectricityemissionfactorsofChinabyregions.RegionEmissionfactor(kgCO2-eq/kWh)NorthChina0.9419Northeast1.0826EastChina0.7921CentralChina0.8587Northwest0.8922SouthChina0.8042B.3BUILDINGMATERIALEMISSIONFACTORSTableB.3Summaryofemissionfactorsbybuildingmaterial.MaterialCarbonemissionfactorPebble11.29kgCO2/m3Plantingsoil0.024kgCO2/tClaysoil2.69kgCO2/tSandysoil2.51kgCO2/tGravel6.05kgCO2/tHerbs0.024kgCO2/tShalerock5.08kgCO2/tGravel2.18kgCO2/tBoulder2.18kgCO2/tRocks2.18kgCO2/tGradedcrushedstone52.8kgCO2/m3Middlesand2.51kgCO2/tGabion11.36kgCO2/tShalesolidbrick292kgCO2/m2Sand-freeconcretepermeablebrick336kgCO2/m3Sand2.51kgCO2/kgSinteredstandardbrick134kgCO2/m3Grassbrick336kgCO2/m3Permeablebrick2.21kgCO2/m3Woodpile144.5kgCO2/m3144ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorMaterialCarbonemissionfactor1:2cementmortar531.52kgCO2/m³1:2.5cementmortar158.75kgCO2/m³1:3cementmortar393.65kgCO2/m31:6cementmortar140.16kgCO2/m3735kgCO2/tCement186.43kgCO2/m³C15Concrete239.19kgCO2/m3C20Concrete289.44kgCO2/m3C25Concrete295kgCO2/m3C30Concrete355kgCO2/m3Finestoneconcrete2340kgCO2/t3150kgCO2/tRebar2170kgCO2/tSeamlesssteelpipe228.03kgCO2/m3315.39kgCO2/m3FRP7.93kg/kgMasonryMortarDM5.0-HR144.5kgCO2/kgMasonryMortarDM10-HR1.46kgCO2/kgUPVCperforatedcollectiontube10.28kgCO2/kg4.46kgCO2/kgPlantfiberblanket2.37kgCO2/m2Bentonitewaterproofblanket10280kgCO2/t2620kgCO2/tHDPEgeomembrane2.37kgCO2/m2Compositewaterproofmembrane10.28kgCO2/kg1765kgCO2/tSBScoil2620kgCO2/tPermeablegeotextile1939kgCO2/tHDPEcompositefilmSBSmodifiedbitumenwaterproofmembranePolyesternon-wovenfabricPVCrow(storage)waterboardPolyethylenegeomembranePPPolypropyleneB.4EMISSIONFACTORSFORVARIOUSMODESOFTRANSPORTATIONTableB.4Summaryofemissionfactorsfortransportationbyload.ModeoftransportationEmissionfactor(kgCO2-eq/(tkm))Gasolinetruck(2t)0.334Gasolinetruck(8t)0.115Gasolinetruck(10t)0.104Gasolinetruck(18t)0.104Dieseltruck(load2t)0.286Dieseltruck(8tload)0.179145Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorDieseltruck(load10t)0.162Dieseltruck(load18t)0.129Dieseltruck(load30t)0.078Dieseltruck(load46t)0.0570.010Electriclocomotive0.011Diesellocomotive0.010Railway(onaverageinChina)0.019Tankertransportation(load2000t)0.015Drybulkcarrier(capacity2500t)0.012Containership(200TEUload)B.5EMISSIONFACTORSOFVARIOUSCHEMICALSTableB.5Summaryofemissionfactorbychemicals.ChemicalEmissionfactorChemicalEmissionfactor(kgCO2-eq/kg)(kgCO2-eq/kg)8.010.660.462Ozone14.70.37511.36±3.3510.985Methanol0.61±0.27Aceticacid0.8520.018Sodiumacetate0.6230.029Sulfuricacid0.14Diammoniumhydrogen0.0380.182phosphate0.03±0.000.180.16±0.02Ferroussulfate0.3950.077Hydrochloricacid1.200.3950.26±0.140.61.080.78PAC0.4550.93±0.150.537Ferricchloride0.31.260.53±0.061.741.10±0.600.921.480.16Sodiumhypochlorite1.0650.99±0.07Liquidchlorine0.41Oxygen0.2260.32±0.09Lime0.59Sodiumcarbonate1.84Polyacrylamide0.4150.95±0.63Aluminumsulfate1.Thedatainboldinthetableistheaverageemissionfactor.146Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorB.6CH4EMISSIONFACTORSFORCENTRALIZEDWASTEWATERTREATMENTInthewastewatertreatmentplantsthatreceivingdomesticwastewater,alargequantityofCH4andN2Oisproducedduetothebiologicalprocesses.Thispartofcarbonemissionisdenotedasdirectemissionofthewatersectorandcannotbeexcludedoutoftheboundary.Byfar,theaccountingmethodsforthesetwogasesincludesemissionfactormethodandmodel-basedmethod(Huietal.,2022;Katietal.,2018).Thereinto,emissionfactormethodistheonemostwidelyappliedinwhichthekeyistoobtainaspecificemissionfactor.Inthe2019Refinementtothe2006IPCCGuidelinesforNationalGreenhouseGasInventories(IPCC,2019)released,IPCCprovidedintegratedemissionfactorsforCH4andN2OaccountingwhicharewidelyconvincingandgenerallycitedforCH4andN2Oquantification.Equation(B.1)and(B.3)aretheequationsprovidedintheIPCC’sguidelines.𝐶𝐻4𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑗=(𝑇𝑂𝑊𝑗−𝑆𝑗)×𝐸𝐹𝑗−𝑅𝑗(B.1)𝑆𝑗=𝑆𝑚𝑎𝑠𝑠∙𝐾𝑟𝑒𝑚∙1000(B.2)𝐸𝐹𝑗=𝐵0∙𝑀𝐶𝐹𝑗(B.3)Where:𝐶𝐻4𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑗—CH4emissionsfromwastewatertreatmentininventoryyear,kgCH4/a𝑇𝑂𝑊𝑗—Influentorganicsofwastewatertreatmentplantininventoryyear,kgBOD5/a𝑆𝑗—Organicmatterremovedfromwastewatertreatmentintheformofsludgeininventoryyear,kgBOD5/a.SeeEquation(B.2)𝐸𝐹𝑗—CH4emissionfactor,kgCH4/kgBOD5.SeeEquation(B.3)𝐵0—MaximumCH4productioncapacity,kgCH4/kgBOD5.Defaultis0.6𝑀𝐶𝐹𝑗—CH4correctionfactor.SeeTableB.6𝑆𝑚𝑎𝑠𝑠—Amountofrawsludgeremovedasdrymass,t/a𝐾𝑟𝑒𝑚—Sludgefactor,kgBOD5/kgsludge.SeeTableB.7—AmountofCH4recoveredfromtreatmentininventoryyear,kgCH4/a.Default𝑅𝑗is0TableB.6DefaultMCFvaluesbytreatmentprocess.MCFTreatmentprocess0.030.8Centralized,aerobictreatmentplant0.2Anaerobicreactor(e.g.,UASB)0.8AnaerobicshallowlagoonandfacultativelagoonsAnaerobicdeeplagoonTableB.7Removaloforganiccomponentfromwastewaterassludge(Krem).TreatmenttypeKrem(kgBOD5/kgdrysludge)DefaultsRangeMechanicaltreatmentplants0.50.4~0.6Aerobicwastewatertreatmentplantswithout1.0~1.51.16separateprimarytreatment147Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorAerobictreatmentplantswithprimarytreatment0.80.65~0.950.8~1.2Aerobictreatmentplantswithprimarytreatment1.0andanaerobicsludgedigestionTheemissionfactorsforCH4accountingprovidedbyIPCCisbasedonthedatafrom14wastewatertreatmentplantsbyliteraturereview.AssummarizedinTable(B.8),acollectionof7scientificstudieswereselectedaccordingtothecriteriaofbeingfull-scalewastewatertreatmentplantandprovidingkeyinformation.Overall,anMCFof0.03wascalculatedforaerobicwastewatertreatmentplantsandthecorrespondingemissionfactorofCH4is0.018kgCH4/kgBOD.AccordingtoEquation(B.1),theactivitydataistheorganicmatterwhichisobtainedbyexcludingthatintheformofsludge.Thus,theemissionfactorshouldbecalculatedtomatchtheequation.However,bygoingthroughthe7scientificarticles,itshowsthattheemissionfactorsofsomestudieswerecalculatedwithoutsubtractingtheBODdischargedintheformofsludge.Inotherwords,theemissionfactorprovidedbyIPCCdoesnotmatchtheequationprovided.Besides,someerrorsofcitingdatawerefoundinIPCC’sguidelines.Therefore,thisguidelineoptimizestheequationforaccountingforCH4emission.Meanwhile,theguidelinecorrectsandupdatestheemissionfactorbyincludingmorelateststudies(Table(B.8)).TheupdatedCH4emissionfactorofurbanwastewatertreatmentplantsis0.0121kgCH4/kgBOD-influent.Besides,alocalemissionfactorof0.0036kgCH4/kgBOD-influentiscalculatedforChinaspecifically.TodistinguishthedifferencesinCH4emissionsbydifferenttreatmentprocesses,emissionfactorsforAAO,AO,SBR,oxidationditch(OD),andaerobictreatmentprocessarecalculatedrespectively(Figure(B.1))ItisworthnotingthattheequationprovidedbyIPCismorescientificbecausetheproductionofCH4canonlycomefromthemineralizedportionofBOD.Therefore,theon-situmonitoringofCH4emissionsinfull-scalewastewatertreatmentplantsshouldbepromotedandencouragedtoobtainmoreaccurateCH4emissionfactor.FigureB.1CH4emissionfactorsofdifferentwastewatertreatmentprocesses(numbersinthefigureareaveragevalues).148Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorTableB.8CH4emissionfactorbasedonmeasurementinfull-scalewastewatertreatmentplants1.TypeoftreatmentReferenceMCFEF(kgCH4/kgEF(kgCH4/kgprocessBOD-influent)COD-influent)StudiesreferredbyIPCCActivatedsludge(Stickney)Belluccietal.,20100.0170.0121\ActivatedsludgeBelluccietal.,20100.0040.00251\(Northside)\\Activatedsludge(Egan)Belluccietal.,20100.0140.008260.01ActivatedsludgeCzepieletal.,19930.0130.001650.0053Biologicalnutrientremoval0.0240.0087Daelmanetal.,20130.030.0098(Kralingseveer)0.01270.004Biologicalnutrientremoval0.01272Daelmanetal.,20130.020.0028\(Kortenoord)\Biologicalnutrientremoval0.020880.00078Daelmanetal.,20130.040.0173(Papendrecht)0.0041SequencingbatchreactorDelreetal.,20170.0380.02352\(Holbæk)\\Activatedsludge(Källby)Delreetal.,20170.0480.03048\\BiologicalnutrientremovalDelreetal.,20170.0140.0096\(Lundtofte)\\BiologicalnutrientremovalDelreetal.,20170.0150.00672\(Lynetten)0.003060.0014ActivatedsludgeKozaketal.,20090.090.01240.00077FivesectionsofbardenphoKyungetal.,20150.070.042Anaerobic/Anoxic/AerobicWangetal.,2011a0.0030.00186(A2O)processStudiesfurtherincludedinthisguidelineMBBRprocess3Delreetal.,20170.04152PushstreamRibera-Guardiaet0.000984al.,2019A2OHwangetal.,20160.0077AeratedactivatedsludgeNoyolaetal.,20180.036Anaerobic/aerationtankNoyolaetal.,20180.048OxidationditchMasudaetal.,20180.0032AOMasudaetal.,20180.0024AOMasudaetal.,20180.00075OxidationditchRenetal.,20130.00704A2ORenetal.,20130.0177invertedA2ORenetal.,20130.0014OxidationditchYanetal.,20190.0007344A2OYanetal.,20190.000336invertedA2OYanetal.,20190.001848149ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTypeoftreatmentReferenceMCFEF(kgCH4/kgEF(kgCH4/kgprocessLiuetal.,2014BOD-influent)COD-influent)A2O0.00110.00045SBRLiuetal.,20140.00220.000914AOBaoetal.,20160.0014160.00059SBRBaoetal.,20160.0043680.00182Mean(International)20.0121±0.0140\Mean(domestic)30.0036±0.0050\1.TheitalicvalueiscalculatedbasedtheoriginaldataandtheunderlinedvalueisbasedonmeasurementsinChina.2.Thisemissionfactoriscalculatedbasedonallthevaluesinthetable.3.ThisemissionfactoriscalculatedbasedonthemeasurementsinChina.B.7N2OEMISSIONFACTORSFORCENTRALIZEDWASTEWATERTREATMENTN2OisanotherpotentGHGofwhichtheglobalwarmingpotentialisthreehundredtimesofthatofCO2.Duetotheexistenceofnitrogencompoundsinwastewater,N2Oisproducedinthebiologicalnitrogenremovalprocessesandshouldbeaccountedinsewagesystem.Atpresent,thequantificationofN2Oemissionalsowidelyadoptstheemissionfactormethod(Equation(5.28))inwhichtheaccuracyandrepresentativenessofemissionfactorisvitalimportant.Currently,themostacceptedemissionfactorofN2OforwastewatertreatmentplantsisprovidedbyIPCC.SimilartoCH4emissionfactor,emissionresultswerecollectedfrom13scientificliteratureassummarizedinTable(B.9).BycorrelatingtheN2Oemissionandinfluentnitrogenload(Figure(B.2)),theslopeistheintegratedemissionfactor,i.e.,1.6%(0.016kgN2O-N/kgN-influent).150Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorFigureB.2CorrelationbetweeninfluenttotalnitrogenloadingandN2Oemissions(a.datafromIPCC;b.correcteddatafromIPCC).NoteworthyisthatsomeerrorswerefoundinthedataprocessingforformulatingN2OemissionfactorbyIPCC.Thus,forthefirststep,thedatacitedinFigure(B.2(a))wasdouble-checkedandcorrectedtoobtainanupdatedemissionfactorofN2OwhicharesummarizedinTable(B.9).Bycorrelatingthereviseddata,anewemissionfactorof0.9%(0.009kgN2O-N/kgN-influent)isobtained(Figure(B.2b))whichissignificantlysmallerthanthevaluecalculatedbytheIPCC.Then,thisguidelinedidanotherliteraturereviewwithafocusonstudiesafter2018,and16scientificpaperswereidentifiedandsummarizedinTable(B.9).Then,anupdatedN2Oemissionfactorof0.93%(0.0093kgN2O-N/kgN-influent)wasobtainedwithallthedatainTable(B.9).Besides,thisguidelinealsoprovidesspecificN2Oemissionfactorsfordifferenttreatmentprocesses(Figure(B.4)).151Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorInaddition,thisguidelineexclusivelyanalyzestheN2OemissionfactorofwastewatertreatmentplantsinChina,asshowninFigure(B.3b).Anemissionfactorof1.06%(0.0106kgN2O-N/kgN-influent)isobtainedreferringto6studies.However,thecorrelationcoefficientwaslow,whichindicatedthattheon-sitemonitoringofN2Oinfull-scalewastewatertreatmentplantsinChinaislimitedandshouldbeencouraged.FigureB.3CorrelationbetweeninfluenttotalnitrogenloadingandN2Oemissions(a.basedonglobal-widecasestudies;b.basedonChinaspecificcasestudies).152Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorFigureB.4N2Oemissionfactorsofdifferentwastewatertreatmentprocesses(numbersinthefigureareaveragevalues).TableB.9N2Oemissionfactorbasedonmeasurementinfull-scalewastewatertreatmentplants.TypeofCategoryReferenceOriginaldatainCorrectedtreatmentIPCCguidelinedataintheprocesspresentguidelinekgN2O-N/kgN-influentStudiesreferredtobyIPCCAOBNRDaelmanetal.,20150.0280.028AOBNRFoleyetal.,20100.0210.01321AOBNRFoleyetal.,20100.0450.03A2OBNRFoleyetal.,20100.0130.00562SBRBNRFoleyetal.,20100.0230.0176OxidationditchBNRFoleyetal.,20100.0080.00571EABNRFoleyetal.,20100.0150.0115IntermittentBNRKimochietal.,19980.00050.0005aerationA2OBNRWangetal.,20160.0130.0129ConventionalBNRAboobakaretal.,20130.000360.00036activatedsludge153Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorCorrectedTypeofCategoryReferenceOriginaldataindatainthetreatmentIPCCguidelinepresentprocessBNRRodriguez-CaballeroetBNRal.,2014guidelineAOBNRBNRMasudaetal.,2018kgN2O-N/kgN-influentOxidationditchMasudaetal.,2018AOMasudaetal.,20180.120.00116AO0.000160.000142Biological0.00130.0012nitrogenand0.00490.0037phosphorusBNRAhnetal.,20100.000190.0001273removalBardenphoBNRAhnetal.,20100.00360.00242BiologicalnitrogenandBNRAhnetal.,20100.0110.00706phosphorusremovalbyBNRAhnetal.,20100.00070.000445multi-pointBNRAhnetal.,20100.00060.000382waterinletBNRAhnetal.,20100.00030.0001910.015MLEBNRAhnetal.,20100.00954MLE0.019ContinuedOxidationditchBNRNietal.,20150.029Biological0.0380.019nitrogenandBNRBaoetal.,20160.0040.019phosphorusBNRRodriguez-Caballeroet0.00620.038removalbyNon-BNR0.00180.00226multi-pointNon-BNRal.,20150.0230.00258waterinletAhnetal.,20100.0063Multi-pointAhnetal.,20100.00002299waterinletplugflowreactorNon-BNRAhnetal.,2010SBRNon-BNRMasudaetal.,2015SBRPushstreamPushstreamMulti-pointwaterinletaerationtankPushstream154Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorCorrectedTypeofCategoryReferenceOriginaldataindatainthetreatmentNon-BNRBaoetal.,2016IPCCguidelinepresentprocessguidelineAOIntermittentkgN2O-N/kgN-influentaeration0.0130.009IntermittentNon-BNRdeMelloetal.,20130.00160.0016aerationStudiesfurtherincludedinthisGuidelinesIntermittentaerationBNRKimochietal.,19980.0008AeratedBNRKimochietal.,19980.0001biologicalpoolA2OBNRBrottoetal.,20100.0014SBRBNRWangetal.,2011b0.00068BiologicalBNRDelreetal.,20170.00133nitrogenandphosphorusBNRDelreetal.,20170.0024removalBNRDelreetal.,20170.0004ConventionalBNRDelreetal.,20170.00277activatedsludgeBNRDelreetal.,20170.00074Non-BNRCzepieletal.,19950.00022MBBRBardenphoBNRGruberetal.,20200.018AeratedBNRGruberetal.,20200.01biologicalpoolBNRGruberetal.,20200.024ConventionalBNRTumendelgeretal.,0.00008activatedsludgeBNR20190.00001IntermittentTumendelgeretal.,aerationBNR0.001SBRBNR20190.00228BNRValkovaetal.,20210.00007ConventionalBNRValkovaetal.,20210.01198activatedsludgeValkovaetal.,2021Valkovaetal.,2021MLEIntermittentaerationSBRIntermittentaerationMultistage155Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorCorrectedTypeofCategoryReferenceOriginaldataindatainthetreatmentIPCCguidelinepresentprocessguidelinekgN2O-N/kgN-influentactivatedsludgeBNRValkovaetal.,20210.01184ConventionalBNRValkovaetal.,20210.000295activatedsludgeBNRValkovaetal.,20210.00005PushstreamCSTRBNRValkovaetal.,20210.00516ConventionalBNRValkovaetal.,20210.0085activatedsludgeConventionalBNRValkovaetal.,20210.013activatedsludgeBNRBlombergetal.,20180.0134ConventionalBNRSunetal.,2013a0.056BNRSunetal.,20170.016activatedsludgeBNRSunetal.,2013b0.0186AOBNRSunetal.,2013b0.0625SBRBNRVieiraetal.,20190.000055AONon-BNRVieiraetal.,20190.00143A2OBNRVieiraetal.,20190.000025SBRBNRVieiraetal.,20190.000089A2OBNRVieiraetal.,20190.00051PushstreamBNRCastro-Barrosetal.,0.02MLE2015MLEBNR0.00173MLEBNRYanetal.,20140.00064BNRYanetal.,20140.00055Short-courseBNRYanetal.,20140.000899digestion-BNRRenetal.,20130.000969anammoxBNRRenetal.,20130.000712BNRRenetal.,20130.0105OxidationditchBNRChenetal.,20190.00012InvertedA2OBellandietal.,2018A2ONon-BNR0.0004Bellandietal.,2018OxidationditchBNR0.0005A2OBellandietal.,2018BNR0.0033InvertedA2OvanDijketal.,2021AOAOConventionalactivatedsludgeUCTAerobicgranularsludge156Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestEmissionfactorB.8CARBONSEQUESTRATIONCAPACITYOFDIFFERENTVEGETATIONTableB.10Carbonsequestrationcapacitybydifferentvegetation.VegetationtypesSequestrationfactor[kgCO2-eq/(m2a)]Mixedplantingoftrees,shrubs,flowersand27.5plantsMixedplantingoflargeandsmalltrees22.5Deciduoustree20.2Deciduoussmalltrees,conifers,thin-leaved13.4treesAbout1.25mhighdenselyplantedshrubs10.3Highabout0.85mdenselyplantedshrubs8.2Highabout0.55mdenselyplantedshrubs5.2High1mwildgrass1.2High0.25mlowstemweeds0.4Artificialturf0.0157Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixCConstructioninventoryandintegratedemissionfactorformulationC.1CONSTRUCTIONINVENTORYOFWATERSUPPLYSYSTEMTableC.1Summaryofconstructioninventoryandemissionintensityofwatertreatmentplants.TreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsenergymaterial(tCO2-eq/10000factorfactorconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000m3)yuan)000m3)000m3)1.027ConventionaltreatmentSmall-scaleCement607.680t/10000-446.6450.693447.338plantWood144.000m30.16420.972-20.808(<50000m3/10000m3/d)m3Continued159Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsMedium-energymaterial(tCO2-eq/10000factorfactorscaleplantconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(50000m3)yuan)m3/d~100000m3)000m3)000m3/d)Rebar194.418t/10000-454.9380.222455.160m3Sand313.600-1.1020.3581.459Gravel2352.000m3/10000-7.6912.68110.372Steelpipeandfittingsm3-96.1910.04396.23438.020m3/m376.392Dieselfuel25.212t/10000101.564-0.02976.421Electricity17.394177.956--101.564Totalm31027.3751209.520Cement540.956t/10000-397.6034.189398.2190.617m3-Wood99.000kWh/m314.3060.11314.4181.018-Rebar173.266t/10000405.4420.198405.640m3m3/10000m3t/10000m3Continued160Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsLarge-scaleenergymaterial(tCO2-eq/10000factorfactorplantconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(≥100000m3)yuan)m3/d)000m3)000m3)Sand137.900m3/10000-0.0480.1570.206Gravel1969.000m3-Steelpipeandfittings-6.4392.2458.68333.207m3/m3t/1000068.49084.0140.03884.05291.053Dieselfuel22.604m3159.543-0.02668.516Electricity15.594t/10000--91.053Total-907.8521070.787Cement416.907m3306.4263.393306.902kWh/m3-0.475Wood76.125t/10000-8.71630.0878.803m3311.0340.152311.185Rebar132.920-0.996m3/10000-Sand648.925m32.2800.7403.020Gravel1611.2501615.2691.8377.106t/10000m3m3/10000m3m3/m3ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsSmall-scaleenergymaterial(tCO2-eq/10000factorfactorplantconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(<50000m3)yuan)m3/d)000m3)000m3)1.027Steelpipeandfittings27.151t/1000068.6930.03168.724-0.02154.682m3-72.666833.087Dieselfuel18.040t/1000054.661-3.342Electricity12.445m3TotalkWh/m372.666-127.327702.4183Pretreatment+conventionaltreatmentCement743.748t/10000546.6550.848547.503-0.15619.9530.266546.989m30.4321.7622.99511.585Wood137.000m3/1000019.7970.04497.170m3-Rebar233.642t/10000546.722-m3Sand378.600m3/100001.330Gravel2627.000m3-Steelpipeandfittings38.390m3/m3-8.590t/1000097.127-m3Continued162Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsMedium-energymaterial(tCO2-eq/10000factorfactorscaleplantconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(50000m3)yuan)m3/d~100000m3)000m3)000m3/d)Dieselfuel31.298t/1000094.833-0.03694.869Electricity21.592m3126.076Total220.909--126.076Cement672.116kWh/m31220.2214.7761445.906-t/10000494.0050.766494.771m3-Wood12718.3520.14518.496m3/10000-Rebar211.176m3494.1520.241494.393-Sand171t/10000-0.0600.1950.2551.036Gravel2443m3-7.9892.78510.774Steelpipeandfittings33.83985.6130.03985.651m3/1000084.298Dieselfuel27.821m3112.0620.03284.329Electricity19.192m3/m3163--112.062t/10000m3t/10000m3kWh/m3ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsLarge-scaleenergymaterial(tCO2-eq/10000factorfactorplantconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(≥100000m3)yuan)m3/d)000m3)000m3)1.006Total196.361100.1714.2021300.7320.583376.151Cement510.978t/10000-375.568Wood10.9780.10911.087m30.188387.05895.875m3/10000-0.9173.742m32.0477.9170.03270.946Rebar165.329t/10000-386.870Sand2.8260.02566.211m3-87.9881011.100804.075m3/10000-3.900m3Gravel1795.250m3/m3-5.870Steelpipeandfittings28.029t/10000-70.914m3Dieselfuel21.844t/1000066.186-m3Electricity15.069kWh/m387.988-Total154.174853.026Pretreatment+conventionaltreatment+advancedtreatmentContinued164Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsSmall-scaleenergymaterial(tCO2-eq/10000factorfactorplantconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(<50000m3)yuan)m3/d)000m3)000m3)Medium-Cement1014.540t/10000-745.6871.157746.843scaleplantm3Wood174.000-25.1430.19825.341m3/10000Rebar311.392m3-728.6570.355729.012Sand463.000t/10000-1.6270.5282.1550.994Gravel3432.000m3-11.2233.91215.135Steelpipeandfittings-129.7080.058129.76651.268m3/10000m3126.448Dieselfuel41.732168.093-0.048126.4961.008Electricity28.788m3/m3294.541--168.093Totalt/100001642.0451942.842Cement934.611-686.9396.256688.005m31.065t/10000m3kWh/m3t/10000m3Continued165Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissions(50000energymaterial(tCO2-eq/10000factorfactorm3/d~100consumptionconsumptionm3)(tCO2-eq/10000(tCO2-000m3/d)(tCO2-eq/10(tCO2-eq/10eq/10000m3)yuan)Large-scale000m3)000m3)plantWood153.000m3/10000-22.1090.17422.283(≥100000m3m3/d)Rebar284.550-665.8470.324666.171t/10000Sand211.300m3-0.0740.2410.315Gravel3116.000-10.1893.55213.742Steelpipeandfittingsm3/10000-118.7580.054118.81246.940m3118.543Dieselfuel39.123m3/m3157.589-0.045118.587Electricity26.989t/10000276.132--157.589Total1503.9161785.503Cement754.789m3-554.7705.455555.630t/100000.860-13.88314.0210.993m30.138Wood121.250kWh/m3t/10000m3m3/10000m3Continued166Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsSmall-scaleenergymaterial(tCO2-eq/10000factorfactor(<50000consumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000m3/d)m3)yuan)000m3)000m3)1.004Rebar227.828t/10000533.1180.260533.377-1.1974.888m32.84811.0190.04496.808Sand1050.213m3/100003.690Gravel2498.625-0.03695.199Steelpipeandfittings-126.51038.247m31437.4535.383m3/m3-8.171t/1000096.765-m3Dieselfuel31.407t/1000095.164-Electricity21.666m3TotalkWh/m3126.510-221.6741210.397WaterdistributionpumpstationCement193.636t/10000142.3220.221142.543Wood36.000-5.2020.0415.243Rebar61.9180.071m3144.959m3/10000-m3t/10000144.888-m3Continued167Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsMedium-energymaterial(tCO2-eq/10000factorfactorscaleconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000(50000m3)yuan)m3/d~100000m3)000m3)000m3/d)Sand96.800m3/10000-0.3400.1100.451Gravel727.000m3Steelpipeandfittings-2.3770.8293.2064.372m3/m3t/10000-11.0610.01411.075Dieselfuel12.024m336.433-0.00936.442Electricity7.824t/1000045.684--45.684Total82.117306.191389.602Cement174.017m3127.9021.294130.083kWh/m3-2.180Wood31.000t/10000-4.4800.1984.678m30.035129.8470.975m3/10000Rebar55.475m3-129.812Sand44.400t/10000-0.0160.0630.079Gravel634.000m30.0512.124-2.073m3/10000m3m3/m3Continued168Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionsEmissionsintensityIntegratedCapital-capacityintensityofintensityofoftransportation1emissionsbasedemissionsenergymaterial(tCO2-eq/10000factorfactorconsumptionconsumptionm3)(tCO2-eq/10000(tCO2-(tCO2-eq/10(tCO2-eq/10eq/10000m3)yuan)000m3)000m3)0.989Steelpipeandfittings10.305t/10000-26.0720.72326.794m30.01221.085Dieselfuel6.955t/1000021.074-0.00828.023-339.443m396.6790.150Electricity4.798kWh/m328.016-0.0282.8620.04898.157Total49.090290.3550.2420.9870.5942.296Cement131.333-t/10000m396.5300.0108.0710.00625.360Wood24.750-m3/10000m32.83432.362-266.774Rebar41.927-t/10000m398.1091.077Large-scaleSand212.063-m3/10000m30.745(≥100000Gravel520.625-m3/m31.702m3/d)Steelpipeandfittings3.186-t/10000m38.061Dieselfuel8.36825.354t/10000m3-Electricity5.54232.362kWh/m3-Total57.716207.9811.Calculatedwith20kilometerstransportedbyheavy-dutydieseltrucks(withaloadcapacityof46tons).Continued169Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorC.2CONSTRUCTIONINVENTORYOFWATERDISTRIBUTIONNETWORKSTableC.2Summaryofconstructioninventoryandemissionintensityofwaterdistributionnetworks.PipesDiameterEmissionintensityEmissionintensityofEmissionintensityofIntegratedemissionCapital-basedofmaterialconstructionoperation(pertransportation1factoremissionfactormeterburieddepth)(tCO2-(tCO2-eq/10000yuan)consumption(tCO2-eq/km)(20km)(tCO2-eq/km)(tCO2-eq/km)eq/(kmm))1.331.54DN300103.282.470.05105.071.602.12DN400153.442.700.08155.412.422.91DN500211.583.270.11213.983.133.40DuctileDN600278.163.390.14280.674.051.88ironDN700353.403.620.18356.111.991.90pipeDN800437.764.120.22440.872.402.68DN900528.964.350.26532.272.982.91DN1000627.004.580.31630.522.983.16DN1200852.045.020.43855.97DN300179.532.470.08181.34DN400226.652.680.11228.63DN500284.803.250.13287.21DN600342.873.400.16345.41SteelDN700400.713.590.19403.41pipeDN800458.784.070.22461.85DN900516.624.290.24519.86DN1000574.704.500.27578.11DN1200690.614.930.32694.381.Calculatedwith20kilometerstransportedbyheavy-dutydieseltrucks(withaloadcapacityof46tons).170Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationC.3CONSTRUCTIONINVENTORYOFWASTEWATERSEWERTableC.3Summaryofconstructioninventoryandemissionintensityofwastewatersewer.PipesDiameterEmissionintensityofEmissionintensityofEmissionsIntegratedCapital-basedmaterialconsumptionconstructionoperation(perintensityofemissionfactor2emissionfactor(tCO2-eq/km)meterburieddepth)transportation1(tCO2-eq/km)(tCO2-eq/10000(tCO2-eq/(kmm))(tCO2-eq/km)yuan)52.43.1Reinforceddn600341.315.50.2986.74.3126.75.2concretedn80070.921.80.50178.86.1263.58.1pipedn1000106.228.30.72346.48.8414.99.2dn1200152.136.61.03536.510.717.90.5dn1400234.539.21.5920.80.524.40.5dn1600309.549.72.1029.90.536.10.5dn1800373.555.62.4344.10.549.60.5dn2000491.560.02.9955.10.5HDPEDN6004172.618.20.002pipeDN800292.218.50.003DN1000455.919.20.005DN1200547.821.00.007DN1400596.721.60.009DN1600656.421.90.013DN1800716.122.20.015DN2000835.422.50.0171.Calculatedwith20kilometerstransportedbyheavy-dutydieseltrucks(withaloadcapacityof46tons).Continued171Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector2.Constructionemissionintensityinthetotalemissionintensityiscalculatedwithadepthofcoverof0.7m(accordingto“GB50014-2021(2021Edition)Standardfordesignofoutdoorwastewaterengineering”theminimumburialdepthofthepipetopundertheroadwayshouldbe0.7m).3.Thediameterofconcretepipesandotherpipesisrepresentedbytheinnerdiameterofthepipe,denotedas“dn”.4.Thepipediameterisrepresentedbythenominaldiameter“DN”,whichistheaverageoftheouterdiameterandinnerdiameterofthepipe.C.4CONSTRUCTIONINVENTORYOFWASTEWATERTREATMENTPLANTSTableC.4Summaryofconstructioninventoryandemissionintensityofwastewatertreatmentplants.TreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.3m3)m3)ContinuedWastewatertreatmentplants(excludingsludgedigestion)withClassBdischargestandardsCement1953.2t/10000-1435.62.21437.8m3Small-scaleWood247.0m3/10-0.00.30.3plant000m3(<10000Rebar421.2t/10000-985.60.5986.1m3/d)m3m3/10Sand4771.0000m3-16.85.422.2Gravel7787.0m3/m3-24.68.933.5172Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.3m3)m3)ContinuedSteelpipe89.6t/10000-226.70.1226.8andm379.7247.10.00.1247.2fittings550.0t/10000DieselTotalm3321.10.0-321.1fuel1176.5568.2Electricity150.0MWh/102689.317.53275.0317.1000m3-Cement3375.0864.71.3866.14690.0t/10000-Medium-Woodm30.00.20.2scaleplant-Rebarm3/10742.00.4742.4(10000000m3-m3/d~100Sandt/10000-11.93.815.7000m3/d)Gravelm3m3/1014.85.320.2000m3m3/m3173Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.1m3)m3)ContinuedSteelpipe54.0t/10000-136.60.1136.7andm364.3199.3-0.1199.4fittings444.0t/10000DieselTotalm3259.3--259.3fuel951.0458.6120.0MWh/10Electricity241.4000m3-2663.33800t/10000-1770.111.22239.9m3Cement-699.01.1700.1m3/10Large-scaleWood000m3-0.00.10.2plantRebart/10000-Sand564.90.3565.2(≥100000Gravelm3m3/d)m3/10000m3m3/m39.43.012.412.04.316.3174Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactorSteelpipetransportation1(tCO2-eq/10000(tCO2-eq/10000Smallandenergymaterial(tCO2-eq/10000factoryconsumptionconsumptionm3)yuan)(<10000fittings(tCO2-eq/10000(tCO2-eq/10000m3)m3/d)Diesel1.3fuelm3)m3)ContinuedElectricity43.7t/10000-110.60.0110.6CementWoodm3RebarSand55.0t/10000170.5-0.1170.6Gravel380.0Totalm32519.6MWh/100.0--0.0319.0543.4000m36155.010045.0170.51395.89.01575.3Wastewatertreatmentplants(includingsludgedigestion)withClassBdischargestandardst/100001851.92.91854.8-m3m3/100.10.40.4-000m3t/100001271.60.61272.2-m3m3/1021.67.028.6000m3-m3/m3-31.811.543.2175Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe115.6t/10000-292.50.1292.6andm3103.0319.3-0.1319.4fittings711.0t/10000DieselTotalm3415.2--415.2fuel1446.1734.5Electricity184.6MWh/103469.422.64226.4311.9000m3-Cement3534.01062.91.61064.55765.0t/10000-Medium-Woodm30.00.20.2scaleplant-Rebarm3/10729.80.4730.2(10000000m3-m3/d~100Sandt/10000-12.44.016.4000m3/d)Gravelm3m3/1018.26.624.8000m3m3/m3176Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe66.4t/10000-168.00.1168.1andm375.7234.7-0.1234.8fittings522.0t/10000DieselTotalm3304.8--304.8fuel1131.4539.5140.0MWh/10Electricity243.2000m3-2766.54515.5t/10000-1991.413.02543.8m3Cement-831.61.3832.9m3/10Large-scaleWood000m3-0.00.20.2plantRebart/10000-Sand569.10.3569.4(≥100000Gravelm3m3/d)m3/10000m3m3/m39.73.212.914.35.119.4177Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactorSteelpipetransportation1(tCO2-eq/10000(tCO2-eq/10000Small-scaleandenergymaterial(tCO2-eq/10000plantconsumptionconsumptionm3)yuan)fittings(tCO2-eq/10000(tCO2-eq/10000m3)(<10000Diesel1.3m3/d)fuelm3)m3)ElectricityContinued51.9t/10000-131.30.1131.4CementWoodm3RebarSand64.1t/10000198.7-0.1198.8Gravel442.0Totalm32832.1MWh/10258.1--258.1358.0610.8000m36918.011291.0456.81556.010.22022.9Wastewatertreatmentplants(excludingsludgedigestion)withClassAdischargestandardst/100002081.63.22084.8-m3m3/100.10.40.5-000m3t/100001429.30.71430.0-m3m3/1024.37.932.2000m3-m3/m3-35.712.948.6178Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe130.0t/10000-328.90.1329.0andm3115.6358.4-0.1358.5fittings797.0t/10000DieselTotalm3465.4--465.4fuel1658.8823.7Electricity211.5MWh/103899.825.44748.9357.7000m3-Cement4053.81219.21.91221.16612.9t/10000-Medium-Woodm30.00.20.3scaleplant-Rebarm3/10837.00.4837.4(10000000m3-m3/d~100Sandt/10000-14.24.618.9000m3/d)Gravelm3m3/1020.97.528.4000m3m3/m3179Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe76.1t/10000-192.50.1192.6andm387.1270.0-0.1270.1fittings601.0t/10000DieselTotalm3350.9--350.9fuel1282.5620.9158.5MWh/10Electricity275.7000m3-3136.05119.0t/10000-2284.014.92919.8m3Cement-942.61.5944.1m3/10Large-scaleWood000m3-0.00.20.2plantRebart/10000-Sand645.10.3645.5(≥100000Gravelm3m3/d)m3/10000m3m3/m311.03.614.616.25.822.0180Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactorSteelpipetransportation1(tCO2-eq/10000(tCO2-eq/10000Small-scaleandenergymaterial(tCO2-eq/10000plantconsumptionconsumptionm3)yuan)fittings(tCO2-eq/10000(tCO2-eq/10000m3)(<10000Diesel1.3m3/d)fuelm3)m3)ContinuedElectricity58.9t/10000-149.00.1149.1CementWoodm3RebarSand72.6t/10000225.1-0.1225.1Gravel501.0Totalm33379.0MWh/10292.5--292.5427.0728.7000m38254.013472.0517.61764.011.52293.1Wastewatertreatmentplants(includingsludgedigestion)withClassAdischargestandardst/100002483.63.92487.4-m3m3/100.10.50.6-000m3t/100001705.20.81706.0-m3m3/1029.09.438.4000m3-m3/m3-42.615.457.9181Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)0.9m3)m3)ContinuedSteelpipe153.9t/10000-389.40.2389.5andm3137.2425.3-0.2425.5fittings946.0t/10000DieselTotalm3552.4--552.4fuel1419.0977.7Electricity181.9MWh/104649.830.35657.7306.0000m3-Cement3468.61043.01.61044.65655.7t/10000-Medium-Woodm30.00.20.2scaleplant-Rebarm3/10716.00.3716.4(10000000m3-m3/d~100Sandt/10000-12.24.016.1000m3/d)Gravelm3m3/1017.96.424.3000m3m3/m3182Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe65.1t/10000-164.70.1164.8andm375.3233.4-0.1233.5fittings519.0t/10000DieselTotalm3303.0--303.0fuel1538.6536.4190.5MWh/10Electricity330.7000m3-3763.06141.5t/10000-1953.812.72503.0m3Cement-1130.91.81132.6m3/10Large-scaleWood000m3-0.00.20.3plantRebart/10000-Sand773.80.4774.2(≥100000Gravelm3m3/d)m3/10000m3m3/m313.24.317.519.47.026.4183Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000Small-scaleenergymaterial(tCO2-eq/10000plantconsumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)(<100001.3m3/d)m3)m3)ContinuedSteelpipet/10000and70.6m3-178.60.1178.7fittingsDiesel87.1t/10000270.0-0.1270.1fuelm3Electricity601.0MWh/10350.9--350.9000m3Total620.92116.013.82750.8Upgradingandtransformingofwastewatertreatmentplants(excludingsludgedigestion)toClassAdischargestandardsCement957.1t/10000-703.51.1704.6m3Wood121.0m3/10-0.00.10.2000m3Rebar206.4t/10000-483.00.2483.2m3m3/108.22.710.9Sand2338.0000m3-Gravel3816.0m3/m3-12.14.416.4184Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe43.9t/10000-111.10.1111.1andm338.7120.0-0.0120.0fittings267.0t/10000DieselTotalm3155.9--155.9fuel589.2275.9Electricity75.1MWh/101317.88.61602.3127.1000m3-Cement1439.9433.10.7433.72348.9t/10000-Medium-Woodm30.00.10.1scaleplant-Rebarm3/10297.40.1297.6(10000000m3-m3/d~100Sandt/10000-5.11.66.7000m3/d)Gravelm3m3/107.42.710.1000m3m3/m3185Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.2m3)m3)ContinuedSteelpipe27.0t/10000-68.30.068.3andm331.096.1-0.096.1fittings214.0t/10000-DieselTotalm3125.0811.3-125.0fuel444.7221.1326.955.0MWh/100.0Electricity95.6000m3-223.71087.53.81775.0t/10000-5.65.31037.6m3Cement-0.5327.4m3/10Large-scaleWood000m3-0.10.1plantRebart/10000-Sand0.1223.8(≥100000Gravelm3m3/d)m3/10000m3m3/m31.25.12.07.6186Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000Small-scaleenergymaterial(tCO2-eq/10000plantconsumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)(<10000m3/d)m3)m3)Steelpipet/10000and20.4m3-51.60.051.6fittingsDiesel25.0t/1000077.5-0.077.5fuelm3Electricity173.0MWh/10101.0--101.0000m3Total178.5611.64.0794.1Upgradingandtransformingofwastewatertreatmentplants(excludingsludgedigestion)topseudoClassIVdischargestandardsCement1445.3t/10000-1062.31.61063.91.3m3Wood183.0m3/10-0.00.20.2000m3Rebar311.7t/10000-729.40.4729.7m3m3/1012.44.016.4Sand3531.0000m3-Gravel5762.0m3/m3-18.26.624.8Continued187Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.0m3)m3)ContinuedSteelpipe66.3t/10000-167.70.1167.8andm358.6181.7-0.1181.7fittings405.0t/10000DieselTotalm3236.5--236.5fuel884.3418.1Electricity112.7MWh/101990.112.92421.2190.7000m3-Cement2160.9650.01.0651.03525.5t/10000-Medium-Woodm30.00.10.1scaleplant-Rebarm3/10446.20.2446.5(10000000m3-m3/d~100Sandt/10000-7.62.510.1000m3/d)Gravelm3m3/1011.14.015.2000m3m3/m3188Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)1.0m3)m3)ContinuedSteelpipe40.6t/10000-102.70.0102.8andm346.4143.8-0.1143.9fittings320.0t/10000DieselTotalm30.0--0.0fuel675.9143.983.5MWh/10Electricity145.3000m3-1653.02698.0t/10000-1217.77.91369.5m3Cement-496.80.8497.6m3/10Large-scaleWood000m3-0.00.10.1plantRebart/10000-Sand340.00.2340.2(≥100000Gravelm3m3/d)m3/10000m3m3/m35.81.97.78.53.111.6189Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTreatmentMaterialsConsumptionEmissionEmissionEmissionIntegratedCapital-basedcapacityintensityofintensityofintensityofemissionfactoremissionfactortransportation1(tCO2-eq/10000(tCO2-eq/10000energymaterial(tCO2-eq/10000consumptionconsumptionm3)yuan)(tCO2-eq/10000(tCO2-eq/10000m3)78.5m3)m3)119.1Steelpipe31.0t/10000-78.40.0andm30.038.4119.0-0.01054.7fittings265.0t/10000DieselTotalm30.0--fuel119.1MWh/10Electricity000m3929.66.11.Calculatedwith20kilometerstransportedbyheavy-dutydieseltrucks(withaloadcapacityof46tons).C.5CONSTRUCTIONINVENTORYOFSTORMWATERSYSTEMTableC.5Summaryofconstructioninventoryandemissionintensityofstormwatersystem.CategoryFacilityEmissionintensityEmissionEmissionIntegratedUnitofmaterialintensityofintensityofemissionfactorkgCO2-eq/mconstructiontransportationconsumptionoperation12.758Continued11.933PEtube0.6640.161190Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationCategoryFacilityEmissionintensityEmissionEmissionIntegratedUnitofmaterialintensityofintensityofemissionfactorStormwaterconstructiontransportationkgCO2-eq/m3pipelineconsumptionoperation28.747kgCO2-eq/m3facilities8.04486.578kgCO2-eq/mPipelineSeepagepipe20.3070.3968.416140.282Stormwaterstructures77.7650.3976.262controllingSeepagechannel133.6180.402facilitiesOthertransfer4.880facilitiesDiversionchannel0.40917.220OsmoticTransfertype0.657facilities25.367drygrass17.6790.7783.1418.430kgCO2-eq/m39.9370.194swale51.8280.3340.373GrassPermeable59.7550.420swalesdrygrass11.6845.70919.757kgCO2-eq/m0.130swale11.74636.651kgCO2-eq/m17.68037.891kgCO2-eq/m2Wetgrass39.94080.211kgCO2-eq/m251.830104.031kgCO2-eq/m2swalePermeablSidewalkeDrivingloadpavemen≤5tt(takingDrivingloadpermeabl5~8tecementconcreteDrivingload59.750119.925kgCO2-eq/m23.66615.480kgCO2-eq/m2asan8~13texample)Bioretentionzone191ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorEmissionintensityEmissionEmissionIntegratedofmaterialintensityofCategoryFacilityconstructionintensityofemissionfactorUnitconsumptionoperationtransportation0.662Raingarden35.1148.07443.850kgCO2-eq/m2(Takethepurification0.593151.6660.81613.684165.943kgCO2-eq/m2raingardenasan142.98212.039155.837kgCO2-eq/m2example)0.520Collectionand184.01045.082229.612kgCO2-eq/m2utilizationSimpleecologicaltree0.207facilitiespool10.6084.3722.28113.096kgCO2-eq/m277.86571.4453.35185.588kgCO2-eq/m2Purifyingecologicaltree113.2890.40812.675197.409kgCO2-eq/m2pool7.4409.1503.45811.084kgCO2-eq/m2183.2341.97135.197227.580kgCO2-eq/m3Highflowerbed506.635(Takethelingeringhigh73.9821.93216.786525.392kgCO2-eq/m3flowerbedasan2.34678.260kgCO2-eq/m3example)SunkengreenspaceSimplegreenroofGardentypegreenroofInfiltrationpondSeepagewellReservoir(calculatedaccordingtowaterstoragecapacity)Rainwatertank(PE)192ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestConstructioninventoryandintegratedemissionfactorformulationEmissionintensityEmissionEmissionIntegratedofmaterialintensityofCategoryFacilityconstructionintensityofemissionfactorUnitconsumptionoperationtransportation1.932Rainwatertank62.6232.45067.005kgCO2-eq/m3(fiberglass)0.4900.5187.6888.696kgCO2-eq/m3WetpondDetentionand493.9372.31917.064513.320kgCO2-eq/m3retentionReinforcedconcretefacilitiesrainwaterstoragetank261.6182.33411.530275.482kgCO2-eq/m3(calculatedaccordingtoInterceptionwaterstoragecapacity)117.8142.333Referenceplantingditch135.037kgCO2-eq/mandRainwaterstoragetank197.7786.64514.890291.142kgCO2-eq/m408.9081.95586.72452.435kgCO2-eq/mpurification(module)144.6392.29941.572163.877kgCO2-eq/mfacilitiesVegetationbufferzone48.75416.93977.366kgCO2-eq/mPilerevetment2.58726.025337.265kgCO2-eq/m3GabionrevetmentGrassbrickrevetmentReferencewetpondStonerevetment11.368EcologicalblockrevetmentRainwetlandSedimentationtank325.897Manualconstruction,ignore193Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixDCarbonaccounting:casestudiesD.1CARBONEMISSIONOFWATERSUPPLYSYSTEMAwatertreatmentplantinBeijingwasdesignedwithatotalcapacityof500,000m³/d,whichwouldbeconstructedinthreephases.Currently,thefirstphaseprojectwithacapacityof100,000m³/dhasalreadybeenputintooperation.Therawwateristakenfromanearbyreservoiratarelativelowelevationof40m.Theturbidityisbelow15NTUandthesuspendedsolids(SS)concentrationis10mg/Lonaverage.Acombinationoffour350S75Apumps,eachwithaworkingefficiencyof70%,wasdesignedforthewaterabstractionwiththreepumpsoperatingandoneservingasabackup.Thewateristhentransportedtothewatertreatmentplantandstoredinthetanks.Thefirstphaseoftheprojectincludesfollowingprocess:waterabstraction-coagulation-flocculation-sedimentation-filtration-adsorption-disinfection-waterdistribution.Thecoagulantusedispolyaluminumchloride(PAC),withadosageof20mg/L.Thedisinfectionchemicalisprovidedbytheon-sitechlorinedioxidegenerator,withadosageof1mg/L.Themonthlyelectricityconsumptionis15,000kWh.Theprocurementofchemicalsissourcedwithina20kmradiusoftheprojectsite.Thewastesludgeproducedbythewatertreatmentis4,000m³/d.AndlimeisaddedtoadjustthepH,withadosagebasedon10%ofSS.Thesludgefromwatertreatmentisexportedandtransportedtolandfillsitewith20kmawayforlandfillingdisposalafterconditioning(pre-treatment)anddewatering.Alltransportationusesmedium-sizeddieseltruckswithaloadof8t.Waterpumps(3operatingand1backup)areworkingtodistributethewatertousersatanaveragerelativeelevationof20m.D.1.1ReportingboundariesThereportingboundaryincludesallthecarbonemissionsgeneratedbywaterabstractionstations,treatment,anddistribution.Thepresentcarbonaccountingonlyfocusesontheoperationandmaintenancestage.Themaincarbonemissionactivitiesofthewatersupplysysteminclude:•Indirectcarbonemissionsfromelectricity:Indirectcarbonemissionscausedbytheelectricityconsumptionbytheoperationofwatertreatmentequipmentsuchaswaterabstractionanddistributionpumpsoperationandstirring.•Indirectcarbonemissionsfrommaterials:Mainlyreferstothechemicalsusedinthewatertreatmentandtheirtransportation.IndirectcarbonemissionsaregeneratedbythePACforcoagulation,thechlorinedioxideagentfordisinfection,andthelimeforthesludgeconditioning.Andtheindirectcarbonemissionsfromthetransportationofchemicalsarecausedbyuseofmedium-sizeddieseltrucks.•Indirectcarbonemissionsfromsludgedisposal:Indirectcarbonemissionsfromtransportationofsludgefordisposal.195Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorD.1.2AccountingmethodTheaccountingmethodsfortheemissionactivitiesarereferredtothisGuidelines,andtheequationindexaresummarizedinTableD.1.TableD.1Summaryofaccountingequations.ActivitiesAccountingequationsDataElectricityconsumptionWaterintakeSection5.2:Equationstations(5.2~3)(kWh/d)Actualliftinghead(m)Section5.3:Equation(5.6)ParametersofpumpssuchasElectricityWatertreatmentSection5.2:Equation(5.2)type/efficiency(%)consumptionElectricityconsumptionDistributionSection5.2:Equation(kWh/d)(5.2~3)ElectricityconsumptionChemicalsChemicalsSection5.2:Equation(5.4)(kWh/d)consumptionconsumptionSection5.2:Equation(5.5)Actualliftinghead(m)ParametersofpumpssuchasTransportationtype/efficiency(%)Chemicalsconsumption(kg/d)Transportationload(t),Distance(km)D.1.3DataacquisitionandcollectionAccordingtotheequationssummarizedinTableD.1,theactivitydatarequiredaresummarizedinTableD.2.TableD.2Summaryoftheactivitydata.IndexValueIndexValueChemicaltransport20kmWaterintakehead40mdistance15kmPumpefficiency70%SludgetransportationMedium-sizeddieselWatertreatment500kWh/ddistancetruck(8tload)electricity20m2,000kg/dModeoftransport4.1t/dconsumption100kg/dPACconsumption100kg/dWaterheadClO2consumptionSludgeproductionLimeD.1.4AccountingresultsTheaccountingresultsareshowninTableD.3.196Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesTableD.3Summaryofemissionaccountingresultsofthewatersupplysystem.ActivitiesEmissionintensityAnnualtotalProportionemissions56.7%(kgCO2-eq/m3)(tCO2-eq)1.9%ElectricityWaterintake0.1475,365.528.5%station12.8%0.03%consumptionWatertreatment0.005182.50.057%Distribution0.0742,701-MaterialChemicals0.0331,204.5consumptionTransportation7.59×10-52.78SludgedisposalTransportation1.47×10-45.37Total0.269,462AccordingtoTableD.3,thecarbonemissionsfromtheelectricityconsumptionofpumpstationsandtheuseofchemicalsaccountfor98%ofthetotalcarbonemissionamountinthewatersector.Amongthem,thecarbonemissionscausedbywaterabstractionanddistributionpumpingstationsarethemostsignificantcontributors.Therefore,toreducethecarbonemissionfromtheoperationandmaintenanceinwatersupplysystem,itisnecessarytosignificantlyreducetheelectricityconsumptionofpumpstationsandchemicalsdosage.Inthisproject,thewaterabstractionanddistributionpumpstationsallusethesametypeofpumps,whichisoverlystandardizedandmayresultinpressurewaste.Itisrecommendedtouseacombinationofmultiplevariablefrequencypumpstobettermatchthewaterusageconditionsofusers.Additionally,pressurezoningandwaterdistributioncanbeimplemented.Toreducethechemicalsconsumptionofwatertreatment,therecoveryofsludgecoagulantandestablishmentreal-timedynamicchemicaldosingthroughhydraulicmodellingcanbeconsidered.D.2CARBONEMISSIONOFSEAWATERDESALINATIONPLANTAseawaterdesalinationplantislocatedatTianjinCity,withacapacityof3,000m3/d.Theplantemploysahigh-temperaturebrine-recirculationlong-tubemulti-stageflash(MSF)seawaterdesalinationfacilities,whichproduces18kgfreshwaterper4,681.8Jheatconsumed.Anthraciteisutilizedtoprovidethermalenergyrequired,andthetotaldailyelectricityconsumptionis1,000kWh.D.2.1ReportingboundariesTheorganizationalboundaryoftheseawaterdesalinationcoversentireprocessesfromwaterinflowtooutflowwithintheplantarea.Thereportingboundaryincludesenergyandresourceconsumption,andcarbonemissionassociatedwithmaterialtransportationfromotherenterprises.Theemissionaccountingfocusedontheoperationandmaintenancestage.ThemainGHGemissionactivitiesofthedesalinationplantinclude:•Directemissionfromdesalination:ThisseawaterdesalinationplantusesMSFtechnology.Intheprocessofdesalination,duetothecombustionoffossilfuels,fossilsourceCO2isproduced,resultingindirectemissions.•Indirectemissionsfromresourceandenergyconsumption:Theseawaterdesalinationplantconsumeselectricityandthusindirectemissions.197Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorD.2.2AccountingmethodAccordingtotheGuidelines,thecarbonemissionscalculationmethodsaresummarizedinTableD.4.TableD.4Summaryofaccountingequations.ActivitiesAccountingequationsDataThermalenergyconsumedbyCarbonFossilCO2Section5.3.4Equationdesalinatingunitvolumeofseawateremissions(5.8)Electricity(GJ/m3)fromconsumptionSection5.2.2EquationProportionofeachtypeoffuel(%)desalination(5.2)Dailyelectricityconsumption(kWh/d)plantsDailytreatedwateryield(m³/d)D.2.3DataacquisitionandcollectionAccordingtotheequationssummarizedinTableD.4,theactivitydatarequiredaresummarizedinTableD.5.TableD.5Summaryoftheactivitydata.ValueIndexHeatconsumedbydesalinateaunitvolumeof2.6×106GJ/m3seawaterEmissionfactorofthei-thfuel98.08kgCO2-eq/GJProportionofi-thfuel100%Atotalofntypesoffossilfuelsused1typeDailyelectricityconsumption1,000kWh/dEmissionfactorofelectricityintheregion0.9419kgCO2-eq/kWhDailytreatedwateryield3,000m³/dD.2.4AccountingresultsTheaccountingresultsareshowninTableD.6.TableD.6Summaryofaccountingresultsoftheseawaterdesalinationplant.EmissionintensityAnnualtotalemissionsActivityProportion(kgCO2-eq/m3)(10,000tCO2-eq)7.6%92.4%FossilCO22.55×10-22.79-Electricity0.31kgCO2-eq/m333.9consumptionTotal0.3355kgCO2-eq/m336.74198Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesD.3CARBONEMISSIONOFWASTEWATERTREATMENTPLANTSAwastewatertreatmentplantislocatedatShenzhenCity,GuangdongProvince,withatreatmentcapacityof125,000m3/d.Themainsourceofwastewaterisdomesticwastewater.TheplantemploystheAAOprocess,andproducesabout150tofexcesssludge(withamoisturecontentof80%)everyday.Thesludgeistransportedtoadisposalsite40kmawayforcentralizedincinerationtreatment.D.3.1ReportingboundariesTheorganizationalboundaryofthewastewatertreatmentplantshouldcovertheentireprocessfromtheinfluenttotheeffluent,includingallwastewaterandexcesssludgetreatmentstructures.Thepresentaccountingonlyfocusesontheoperationandmaintenancestage.ThemainGHGemissionactivitiesofthewastewatertreatmentplantinclude:•Directemissionsformwastewatersludgetreatmentprocesses:GHGisproducedfromthemicrobialbiochemicalreactionsdegradingthepollutantsinthewastewater.•Indirectemissionsfromexcesssludgedisposal:ThetreatmentplantadoptsincinerationforthedisposeofexcesssludgeinwhichfossilCO2andN2Owillbeproduced.•Indirectemissionsfromresourceandenergyconsumption:Thetreatmentplantconsumeselectricityforoperation,resultingingeneratingindirectemissions.Polyaluminumchloridewasusedforphosphorusremovalandpolyacrylamidewasusedascoagulant,resultingingeneratingindirectemissions.Additionally,thetransportationofexcesssludgeandchemicalsbetweentheplantandotherenterprises,resultingingeneratingindirectemissions.D.3.2AccountingmethodTheaccountingmethodsfortheemissionactivitiesarereferredtothisGuidelines,andtheequationindexaresummarizedinTableD.7.TableD.7SummaryofaccountingequationsActivitiesAccountingDataequationsBOD5concentrationofinfluentFossilCO2Section5.4.3:Equationandeffluent(mg/L)(5.21~23)TNconcentrationofinfluentandDirectemissionseffluent(mg/L)fromwastewaterSection5.4.3:EquationSludgeretentiontime(SRT)(d)treatment(5.25)Hydraulicretentiontime(HRT)(d)Section5.4.3:EquationMixedliquidvolatilesuspendedCH4(5.28)solidconcentration(mg/L)Watertemperature(°C)N2OSection5.4.3:EquationBOD5concentrationofinfluent(5-39)(mg/L)IndirectemissionsTNconcentrationofinfluent(mg/L)fromsludgeFossilCO2Excesssludgedryweight(kg/d)Excesssludgecarboncontent(%)disposalWastewaterflow(m3/d)199ContinuedDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorActivitiesAccountingDataequationsN2OSection5.4.3:Excesssludgedryweight(kg/d)Equation(5.45)5.2.2:Wastewaterflow(m3/d)IndirectemissionsElectricitySection5.2.3:Electricconsumption(kWh/d)fromresourceandconsumptionEquation(5.2)Wastewaterflow(m3/d)energyChemicalsSectionChemicalsconsumption(kg/d)consumptionconsumptionEquation(5.4)Wastewaterflow(m3/d)Transportationvolume(kg)andTransportationSection5.2.4:distance(km)Equation(5.5)Wastewaterflow(m3/d)D.3.3DatacollectionandacquisitionAccordingtotheequationssummarizedinTableD.7,theactivitydatarequiredaresummarizedinTableD.8.TableD.8Summaryofactivitydata.IndexValueIndexValueWastewaterflow125,000m3/dExcesssludgedryweight30,000kg/dBOD5concentrationofBOD5concentrationof97.13mg/L0.73mg/LinfluenteffluentTNconcentrationof15mg/LFossilCratio1%effluent3,074mg/LTNconcentrationofinfluent37.1mg/LMLVSSconcentration23dWatertemperature23.78℃HRTSRT42,318kWh/d0.42dElectricityconsumption144,80kg/dCcontentofexcesssludge1.2%PolyacrylamideConsumption85kg/dPACConsumptionD.3.4AccountingresultsandanalysisTheaccountingresultsareshowninTableD.9.TableD.9Summaryofaccountingresultsofthewastewatertreatmentplant.AnnualEmissiontotalActivityintensityemissionProportiosn(kgCO2-(10,000t5.08%eq/m3)CO2-eq)1.46%15.53%DirectemissionsfromFossilCO20.0350.157wastewatertreatmentCH40.0100.045N2O0.1040.48Continued200Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesActivityEmissionAnnualProportionintensitytotalIndirectemissionsfromFossilCO20.10%(kgCO2-emissions9.39%sludgedisposalN2Oeq/m3)(10,000t40.13%0.0006CO2-eq)27.83%Electricityconsumption0.0630.2720.003IndirectemissionsfromChemicalsPAC0.1880.29resourceandenergyConsumptionpolyacryl1.24consumption0.0010.86amide0.0030.0050.16%0.6716Transportation0.010.33%Total3.09-FigureD.1Arrangementchartofaccountingresultsofthecasesewagetreatmentplant.TheemissionoffossilCO2fromthewastewatertreatmentprocessisdeterminedbythecompositionofinfluent,andisbeyondthecontrolofwastewatertreatmentplant.TheemissionprofilesofothercarbonemissionactivitiesareshowninFigureD.1.Themainfactorscontributingtocarbonemissionsfromthewastewatertreatmentplantare:(1)indirectcarbonemissionsfromelectricityconsumption;(2)indirectemissionsfrompolyaluminumchlorideconsumedduringthetreatmentprocess.SecondaryfactorisdirectemissionofN2Ogeneratedinwastewatertreatment.Otherfactorsare:(a)N2Oemissionsfromsludgeincineration;(b)CH4emissionsfromwastewatertreatment;(c)fossilCO2emissionsfromsludge201Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorincineration;(d)carbonemissionsfromtransportation;(e)indirectemissionsfromconsumptionofpolyacrylamide.Therefore,inordertoreducethecarbonemissionamountandintensityofthecasewastewatertreatmentplant,effortsshouldprimarybefocusedonreducingthecarbonemissionintensityofthemainfactors,followedbyreducingthecarbonemissionintensityofthesecondaryfactor,andfinallytrytoreducethecarbonemissionintensityofotherfactors.D.3.5DevelopastrategytoreduceemissionsBasedonthecarbonemissionreductionpathwaysofthewastewatertreatmentplantinsection7.5ofthisGuidelines,thefollowingemissionreductionstrategiesareproposedforthecasewastewatertreatmentplant.D.3.5.1CarbonreductionpathwaysofreducingelectricityconsumptionIndirectemissionsfromelectricityconsumptionisthemainfactorofthiswastewatertreatmentplant.Therefore,optimizingtheenergyefficiencyofmechanicalequipmentandreducingelectricityconsumptionareimportantstrategiesforemissionreduction.Thewastewatertreatmentplantshouldconductadetailedanalysisoftheproportionofelectricityconsumption,andsubsequentlyoptimizeandupdateaccordingly.Fortheaerationprocess,thefollowingmeasurescanbetaken:1)adoptingnewequipmentandtechniquestoimproveaerationefficiency,suchasreplacingwithnewhigh-efficiencyequipment,usingmicrobubbleaeration,etc.2)employingpre-feedbackorpost-feedbackaerationoptimizationcontroltechnologytoadjusttheaerationratespromptlytoavoidtheexcessiveaerationandelectricitylosses.3)combiningthebiologicalmodelsandautomaticcontroltechnologytopreciselycontroltheaerationflowrate,therebymaximizingtheelectricityefficiencyoftheaerationsystem.Forwaterpumpunits,thefollowingmeasurescanbetaken:1)maintainingworn-outorcorrodedequipmentintime,andupgradingtonewhigh-efficiencyequipment.2)optimizingtheoperationschemesofwaterpumpunits,includingtheiroperatingstatusandtiming,toavoidinefficientorineffectiveoperation;3)addingfrequencyconversionfunctionalitytothewaterpumpunits,enablingelectricityreductionduringlowflowratetopreventidlingandwastingelectricity.Inaddition,thewastewatertreatmentprocessoftheplantcanalsobemodifiedbyadoptingefficientandlow-carbonprocesses,suchascompactwastewatertreatmentprocess,high-efficiencydenitrificationprocess,etc.,toreducetheelectricityconsumption.D.3.5.2CarbonreductionpathwayofreducingchemicalsconsumptionThepoorwastewatertreatmentperformancerequiresadditionaldosingofpolyaluminumchlorideforchemicalphosphorusremoval,whichisanothermainfactorforthecarbonemissions.Basedonthis,theplantshouldimprovewastewatertreatment,enhancebiologicaltreatmentcapacity,andreducetheconsumptionofpolyaluminumchloridetoeffectivelyreduceitscarbonemissionintensity.D.3.5.3RenewableenergypathwaysInadditiontothecarbonreductionstrategy,theplantcanalsoadopttherenewableenergypathwaystooffsetpartofitscarbonemissionsbyrecyclingresourcesandenergy.Forexample,theashesofsludgeincinerationcanberecycledandprocessedintophosphatefertilizerproductstoreplaceorephosphatefertilizers.Theplantcanalsousewatersourceheatpumptechnologytorecovertheresidualheatinwastewaterandprovidecoolingorheatingforsurroundingareas,replacingtraditionalfireheating,therebyreducingcarbonemissions.202Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesD.4CARBONEMISSIONOFWATERRECLAMATIONPLANTAwaterreclamationplantlocatedatBeijingservesastheupgradingprojectofawastewatertreatmentplant.Halfoftheeffluentwhichis100,000m³/dofthewastewatertreatmentplantisusedasthesourceofthereclaimedwater.TheeffluentiscomposedofBOD5=8mg/L,COD=30mg/L,TN=7mg/L,TP=0.1mg/L,ammonianitrogen=4mg/L,SS=6mg/L,pH=7.5,respectively.Thetreatmentlineinvolvesmicro-flocculation,mediafiltration,disinfection,waterpumpingstationfornon-portableutilization.Thesludgeproducedinreclamationplantishandledwiththesludgefromwastewatertreatmentplant.ThecoagulantusedisPACwithadosageof6mg/L.Thedisinfectionismadebytheon-sitechlorinedioxidegenerator,withadosageof1mg/L.Themonthlyelectricityconsumptionofreclaimedwatertreatmentis10,000kWh.Theprocurementofchemicalsissourcedwithina20kmradiusoftheprojectsite.Alltransportationusesmedium-sizeddieseltruckswithaloadof8t.Centrifugalwaterpumps(3operatingand1backup)areusedtosupplytouserslocatedatrelativeelevationof18m.D.4.1ReportingboundariesTheorganizationalboundaryofthewaterreclamationplantcoversthetreatmentfacilitiesanddistributionpumpingstations.Theemissionaccountingfocusedontheoperationandmaintenancestage.ThemainGHGemissionactivitiesofthewaterreclamationplantinclude:•Indirectcarbonemissionsfromelectricityconsumedbytheoperationofwaterpumpingstationsandtreatmentfacilities.•Indirectcarbonemissionsfrommaterialsandchemicalconsumption,aswellastheirassociatedtransportation,includingPACforcoagulation,thechlorinedioxideagentfordisinfection.D.4.2AccountingmethodTheaccountingmethodsfortheemissionactivitiesarereferredtothisGuidelines,andtheequationsindexaresummarizedinTableD.10.TableD.10Summaryofaccountingequations.ActivitiesAccountingequationsDataElectricityWaterSection5.2:EquationElectricityconsumption(kWh)consumptionpurification(5.2~3)Electricityconsumption(kWh)DistributionSection5.2:EquationActualliftinghead(m)(5.2~3)Parametersofpumpssuchastype/efficiency(%)ChemicalsChemicalsSection5.2:Equation(5.4)Chemicalsconsumption(kg/d)consumptionconsumptionTransportationload(t),DistanceTransportationSection5.2:Equation(5.5)(km)D.4.3DataacquisitionandcollectionAccordingtotheequationssummarizedinTableD.10,theactivitydatarequiredaresummarizedinTableD.11.203Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTableD.11Summaryoftheactivitydata.IndexValueIndexValueModeoftransportMedium-sizeddieselElectricityconsumption333.34kWh/dWaterheadtruck(8tload)PACconsumption600kg/dPumpefficiency18mClO2consumption100kg/d70%Chemicalstransport20kmdistanceD.4.4AccountingresultsTheaccountingresultsareshowninTableD.12.TableD.12Summaryofemissionaccountingresultsofthewaterreclamationplant.EmissionAnnualtotalProportionActivityintensityemissions3.8%(kgCO2-eq/m3)(tCO2-eq)83.52%12.65%ElectricityWaterpurification0.003109.50.03%consumptionDistribution0.0662,409-MaterialChemicals0.01365consumptionTransportation2.5×10-50.9Total0.08kg2,884.4AccordingtoTableD.12,thecarbonemissionsfromtheelectricityconsumptionofthedistributionandtheuseofchemicalsaccountfor96.17%ofthetotalcarbonemissionamountinthewaterreclamationplant.Therefore,toreducethecarbonemissionfromtheoperationandmaintenanceinreclaimedwatersector,itisnecessarytosignificantlyreducetheelectricityconsumptionofdistributionandchemicalsdosage,forexample,adoptingacombinationofmultiplevariablefrequencypumpstobettermatchthewaterusageconditionsofusers.D.5CARBONEMISSIONOFSTORMWATERSYSTEMAcentralurbanareaistakenastheresearchcasewithacatchmentareaof660km2,andacomprehensiverunoffcoefficientof0.7.Theannualrunoffvolumeinthestudyareais4.90×108m3.Basedonfieldmonitoringdataanddrainagestatisticalyearbookdata,thecarbonemissionsfromtheoperationandmaintenanceofthestormwatersystemonlyreferstotheconventionalstormwatercontrolfacilities(i.e.,thedrainagepipenetwork).D.5.1ReportingboundaryThereportingboundarycoversfromthestormwaterpumpingstationtothenaturalwaterbodies,includingallcarbonemissionsgeneratedbythewaterliftingprocess.Thepresentcarbonaccountingonlyfocusesontheoperationandmaintenancestage.Themaincarbonemissionactivitiesinclude:•Directcarbonemissionsfromfossilfuelsforpumpsystemsforrapidstormwaterremovalduringemergencyurbanflooding,resultinginthecarbonemissionsfromthecombustionoffossilfuelfuels.•Indirectcarbonemissionsfromelectricity:Indirectcarbonemissionsfromtheelectricityconsumptionintheoperationofthewaterpumps.204Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesD.5.2AccountingmethodTheaccountingmethodsfortheemissionactivitiesarereferredtothisGuidelines,andtheequationindexaresummarizedinTableD.13.TableD.13Summaryofaccountingequations.ActivitiesAccountingDataequationsActualliftinghead(m)Section5.6:EquationParametersofpumpssuchastype/efficiency(5.46)(%)Parametersofpipesuchasdiameter(mm),FossilfuelsSection5.6:Equationlength(m),flowvelocity(m/s)andsoonconsumption(5.47)Electricityconsumption(kWh/a)Actualliftinghead,headloss(m),ParametersSection5.6:Equationofpumpssuchastype/efficiency(%)(5.48)Section5.6:EquationElectricity(5.49)consumptionSection5.2:Equation(5.2~3)D.5.3DataacquisitionandcollectionAccordingtotheequationssummarizedinTableD.14,theactivitydatarequiredaresummarizedinTableD.14.TableD.14Summaryoftheactivitydata.IndexValueIndexValueAccelerationof9.8m/s2Liftinghead8m1,000kg/m³gravityOilpumpsystemRainwaterdensity5km60%PipelengthefficiencyElectricpumpsystem60%efficiencyD.5.4AccountingresultsAccordingtothecalculationmethodprovidedinthisGuidelines,thecalculationandstatisticalresultsareshownbelow.D.5.4.1CarbonemissionfromstormwaterpressuresewersAseparateddrainagesystemwasappliedinthearea,andliftingpumpsarerequiredtotransferthestormwaterofwhichtheheadlossofpipelinenetworkiscalculatedasfollows.v29Hloss=0.00124×d1.33×L=0.00124×0.31.33×5000=277mWhere:𝑣——theflowvelocity(m/s)𝑑——thediameter(m)ofthepipelines205Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSector𝐿——thelength(m)ofthepipelinesConsideringonlythetreatmentcapacityofstormwaterpipelines,theheadlossofpipelinenetworkcanbecalculatedtobe277m.D.5.4.1.1OilpumpsystemIfthepumpsysteminthestudyareausesdieselwithanemissionfactorof72.59tCO2/TJ(AppendixB.1),thecarbonemissioniscalculatedtobe2.58×105tCO2.n1000×9.8×(8+277)×4.90×108×0.7=3548.1TJρg(Hnet+Hloss)Wrl=∑×Q=ηi0.27i=1CErl=Wrl×EFrl=3548.1×72.59=2.58×105tCO2D.5.4.1.2ElectricpumpsystemIfelectricpumpsareadopted,thecarbonemissioniscalculatedtobe2.57×105tCO2.n1000×9.8×(8+277)×4.90×108×0.7=4.435×108kWhρg(Hnet+Hloss)Ed=∑6×Q=i=13.6×10×ηi3.6×10×0.66CEd=Ed×EFd=4.435×108×0.5810=2.57×105tCO2D.5.4.2CarbonemissionfromstormwatergravitysewersBasedonstormwaterpressuresewersusingelectricpumpsystem,withoutconsideringchangesinflowvelocity,pipediameter,pipelength,pumpefficiency,etc.,onlyapartofthepumpsystemwasredesignedandconvertedtoagravityflowsystem,asshowninTableD.15.TableD.15Carbonemissionsofstormwatersewersunderdifferentgravityflowandpressureflowratioscenarios.SceneGravityPressurePumpstationCarbonflow/%flow/%capacityemissions/10,000t/105m3CO2Conventionaldrainage01003,43025.95(fullpumpdrainage)Scenarioone10903,08723.35Scenariotwo20802,74420.76ScenarioThree30702,40118.16ScenarioFour40602,05815.57Scenariofive50501,71512.97Scenariosix60401,37210.38Scenarioseven70301,0297.78Scenarioeight80206865.19Scenarionine90103432.59Scenarioten(full100000gravityflow)206Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesD.5.4.3CarbonemissionsofstormwatersewerswithsourcereductionAsstatedabove,thesourcereductionofstormwaterisrelyingonthereconstructionofthelow-impactdevelopmentfacilitiesandthedecreaseofurbanrunoff.Itprioritizestheapplicationofnaturaldrainagesystems,andconstructionofecologicaldrainagefacilities,fullyutilizingurbangreenspaces,roads,watersystems,andotherelementsfortheabsorption,retention,andattenuationofstormwater.Itisdesignedthatthetotalannualrunoffcontrolrateinthestudyareais85%,andtheintegratedrunoffcoefficientis0.15withaflowvelocityof2m/s.Withotherdataunchanged,theannualrunoffinthestudyareareducedto7.35×107m3andtheheadlossisthenreduced.v24Hloss=0.00124×d1.33×L=0.00124×0.31.33×5000=124mBasedoncalculations,theheadlossalongthepipelinenetworkis124m.Thecarbonemissionsoftheoilandtheelectricpumpsystemarecalculatedasfollows.D.5.4.3.1OilpumpsystemnWrl=∑ρg(Hneηt+Hloss)×Q=1000×90.8.2×7(8+124)×7.35×107=352.1TJi=1iCErl=Wrl×EFrl=352.1×72.59=2.56×104tCO2D.5.4.3.2ElectricpumpsystemnEd=∑ρg3(.6H×n1et0+6H×loηss)×Q=10030.6××91.80×6(×80+.1624)×7.35×107=4.4×107kWhi=1iCEd=Ed×EFd=4.4×107×0.5810==2.56×104tCO2TableD.16Comparisonofcarbonemissionsfrompressuresewersandsewerswithsourcereductionfacilities.ScenarioIntegratedDiameterAnnualOilpumpsElectricrunoffspeedrunoff/tCO2pumps/tcoefficient/m/m3CO2Pressure0.34.902.57×1052.59×1050.73m/s108sewersPressuresewers0.37.352.56×1042.56×1040.152m/s107withsourcereductionD.6AccountingcasesforwatersectorassociationAlocalwatersectorassociationconsistsof10wastewatertreatmentcompanies,withatotaltreatmentcapacityof150,000m3/d.AccordingtotheproceduresinSection3.3.3,theassociationorganizedandguidedmembercompaniestocarryoutcarbonemissionaccountingwork.207Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorD.6.1AccountingplanThewatersectorassociationformulatedandunifiedtheaccountingplanasfollows.•Accountingboundary:Theorganizationalboundaryshouldcovertheentireprocessesfromtheinfluenttotheeffluent,includingallwastewaterandsludgetreatmentfacilities.Thecarbonaccountingonlyincludesoperationandmaintenancestage.ThemainGHGemissionactivitiesinclude:(I)directemissionsfromwastewatertreatment,(II)directemissionsfromsludgetreatment,(III)indirectemissionsfromresourceandenergyconsumption,andtransportation.•Accountingmethods:TheequationsofSection5.3arereferredinthisGuidelines.•Dataacquisitionandemissionfactors:AccordingtotheprovisionsofChapter8,memberenterpriseshaveagreedonthesameactivitydatamonitoringmethodandselectedthesameemissionfactors.D.6.2AccountingimplementationAccordingtotheaccountingplan,theassociationtakestherolesasfollows.•Supervisingthedataacquisitionworktoensurethequalityofactivitydata.•Providingguidancefortheprocessoftheaccountingworkineachmemberenterprisetoensuretheaccuracyoftheaccountingresults.•SummarizingtheaccountingresultsinTableD.17.TableD.17Summaryofthemembers’carbonemissionaccountingresults.NumberTreatmentTreatmentcapacityCarbonintensityprocess(m3/d)(kgCO2-eq/m3)WastewaterSludgetreatmenttreatment1AAO10,0000.5750.2062AAO20,0000.5970.1813OD20,0000.6380.1114SBR5,0000.6870.1145AAO30,0000.5640.2096Multi-segmentAO10,0000.7630.2257OD10,0000.6520.1218SBR5,0000.5600.1899SBR10,0000.5520.19610AAO30,0000.5420.211Basedontheaccountingresults,theaveragecarbonemissionintensityofwastewatertreatmentiscalculatedasfollows(EquationD.1).C̅̅̅E̅̅S̅∑10(CESi×Qi)=i=1(D.1)∑10Qii=1Where:̅𝐶̅𝐸̅̅𝑆̅—Theaveragecarbonemissionintensityofassociation,kgCO2-eq/m3208Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:Casestudies𝐶𝐸𝑆𝑖—Thecarbonemissionintensityof𝑖-thwastewatertreatmentplant,kgCO2-𝑄𝑖—eq/m3Thedailywatertreatmentvolumeof𝑖-thwastewatertreatmentplant,m3/dTheaveragecarbonemissionintensityoftheassociationmembercompaniesisabout0.78kgCO2-eq/m3.D.6.3FormulatingreportAreportispreparedandsubmittedtotherelevantmanagementdepartment.D.7CarbonemissionofstormwatertreatmentThecarbonemissionsofstormwatertreatmentinacityorregioncanbeestimatedbythefollowingequation(EquationD.2).CECL=5693.8×P×S×n×[0.1a+(1-a)k]+(1-n)×[0.1(1-φ)+k×φ]×(Hnet+Hloss)(D.2)3.6×106ηWhere:𝐶𝐸𝐶𝐿—Carbonemissionsfromstormwatertreatment,kgCO2-eq/a𝑃—Averageannualprecipitation,m𝑛—Spongebuilt-uparearatio𝑆—Areaofbuilt-up,m2𝑎—Totalstormwaterrunoffcontrolratio𝑘—Theproportionofrunoffhandledbypressuresewerintheareaφ—Theintegratedstormwaterrunoffcoefficientsinundevelopedareas.SeeTechnicalGuidelinesforSpongeCityConstruction𝐻𝑛𝑒𝑡—Elevationdifferencebetweenthestartandendpointsofsewer,m𝐻𝑙𝑜𝑠𝑠—Headlossalongthesewer,m,SeeEquation(5.48)𝜂—Pumpsefficiency,%Thetargetedareais1,400km2with21%coveragebyspongefacilitiestoachieve85%totalrunoffcontrolrate.Theproportionofthepressuresewersisk=0.2.Theaverageannualprecipitationis560mm.Theelevationdifferencebetweenthestartingandendingpointsis8m.Theoperatingefficiencyofthepumpstationis0.9.Thestormwaterrunoffcoefficientofthetraditionalundevelopedareaφis0.7.Theheadlossalongthewayiscalculatedtobeabout74.7m.Thecarbonemissionofthestormwatertreatmentoperationiscalculatedasfollows.CECL=5693.8P×S(Hnet+Hloss)=5693.8×P×S××(Hnet+Hloss)×n×[0.1a+(1-a)k]+(1-n)×[0.1(1-φ)+k×φ]=5693.8×1400×560×(8+74.7)×3.6×106η0.21×[0.1×0.85+0.15×0.2]+0.79×[0.1(1-0.7)+0.2×0.7]=2.08×104tCO2-eq3.6×103×0.9209Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorD.8CarbonemissionofthewatersectorinacityAcityislocatedattheNorthChinaPlain,withapermanentpopulationof21million.Thecity'scurrentwaterresourcereservationisabout4.011billionm3/a,ofwhichsurfacewater(excludingevaporativeseepage)reservationis665millionm3/a,riverinflowwateris661millionm3/a,long-distancewaterconveyanceis934millionm3/a,andthegroundwaterstorageis1.751billionm3/a.Thewatermanagementdepartmentofthecityorganizedacarbonemissionaccountingworkregardingthewholewatersector.D.8.1Guidingcompany’saccountingplanThewatermanagementdepartmentofthecityformulatestheaccountingplanforwaterassociationandcompanies.D.8.1.1Determiningtheaccountingboundary:•Watersupplysystem:waterabstractionfacilities,watertreatmentplants,anddistribution•Waterreclamationsystem:watertreatment,anddistribution;•Wastewatertreatmentplants:wastewaterandsludgetreatmentfacilities;•Stormwatersystem:pumpingstationandsourcecontrolfacilities.D.8.1.2UnifyingaccountingmethodsTheaccountingmethodsandequationsrefertoChapter5inthisGuidelines.D.8.1.3SupervisingdataacquisitionThedataacquisitionisaccordingtoChapter8ofthisGuidelines.D.8.1.4SummarizingtheaccountingresultsTheaccountingresultsshouldbesummarizedandanalyzed.D.8.2CarbonaccountingimplementationBasedontheaccountingresultsfromwatersectorassociationsandcompanies,thewatermanagementdepartmentconductedaccountingworkintermsofthewholewatersector.D.8.2.1AnalyzingwaterbalanceThebasicoperationinformationofwatersectorissummarizedbelow.•Watersupplysystem:Therearecurrently130watertreatmentplantsinthecity,withanannualproductionanddistribution(includingleakageloss)capacityof4.06billionm3/a.Amongthisamount,1.70billionm3/aisallocatedfordomesticuse,1.74billionm3/aforecologicaluse,300millionm3/aforindustrialuse,and320millionm3/aforagriculturaluse.Thewatersourcestructureincludes0.85billionm3/aofsurfacewater,1.35billionm3/aofgroundwater,1.20billionm3/aofreclaimedwater,and0.66billionm3/aoflong-distancewaterconveyance.•Wastewatermanagementsystem:Thecityhasanannualwastewaterdischargeof2billionm3/a.Thereisatotallengthof10,000kmofconcretesewagepipelinesinthecity,withaminimumflowrateof0.6m/s.Currently,thereare70wastewatertreatmentplantswithacombinedcapacity210Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:Casestudiesof7millionm3/d,achievingawastewatertreatmentratioof97%.•Waterreclamationsystem:Thereare30waterreclamationplantsinthecity,whichusetheeffluentofwastewatertreatmentplantsaswatersources.Theseplantshaveacapacitytoproduce1.20billionm3/aofreclaimedwaterforindustry,landscapeoragriculture.•Stormwatersystem:Theaverageannualprecipitationinthecityis585mm,withanaverageprecipitationof488mmduringthefloodseason(JunetoSeptember)and97mmduringthenon-floodseason.ThewaterbalanceofthecityisshowninFigureD.2.FigureD.2Waterresourcesinacity'swateraffairssystem.D.8.2.2DeterminationofaverageemissionintensityBasedonthecarbonemissionaccountingresultsofcompanies,appropriateaveragecarbonemissionintensitiesareshowninTableD.18.TableD.18AccountingparametersandsourcesofthecasecityAverageEmissionsitescarbonSourceintensityAverageofintakingcalculation(kgCO2-eq/m3)resultsof20watertreatmentplantsSurfacewaterintaking0.147Averageofintakingcalculationresultsof10watertreatmentplantsWaterGroundwaterintaking1.159supplyLong-distancewater5.93Accountingresultsof1watersectors0.038conservancyprojectconveyanceWatertreatmentAverageofaccountingresultsof30watertreatmentplantsContinued211Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorEmissionsitesAverageSourcecarbonDistributionintensityAverageofaccountingresultsof5(kgCO2-eq/m3)watersupplyenterprisesGravityflowsewer0.074Averageofaccountingresultsof1-WastewaterUntreatedwastewater0.72kmsewagesectorspollution0.427EstimatedvaluebasedonwastewaterReclaimedWastewaterandwaterqualitywatersectorssludgetreatment0.8AnaerobicdigestionAverageofaccountingresultsof20Rainwater-0.32wastewatertreatmentplantssectorsrecoveryReclaimedwater0.08Averageofaccountingresultsof20wastewatertreatmentplantstreatment0.145AverageoftheaccountingresultsofRainwatertreatment10reclaimedwaterplantsAccountingresults1,000-km2spongebuilt-upareaD.8.2.3CarbonemissionofthewholewatersectorAccordingtothewaterbalanceandemissionintensity,thecarbonemissionofthewholewatersectorsiscalculated,andtheresultsareshowninTableD.19.TableD.19Summaryofcarbonemissionsofthewholewatersector.AverageCarbonemissionSystemcarbonAmountofwater(10,000tintensity(100millionm3/a)(kgCO2-CO2)eq/m3)12.50Surfacewater0.1478.5156.47abstraction391.38Groundwater1.15913.510.8730.04Watersupplyabstraction147.022.52systemLong-distancewater5.936.6155.28conveyance-32.00Watertreatmentplant0.03828.6ContinuedDistribution0.07440.6gravityflowsewer0.7220Untreatedwastewater0.4270.59WastewaterpollutionmanagementWastewaterand0.819.41systemsludgetreatmentEnergyrecoveryvia-0.3210anaerobicdigestion212Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesSystemAverageAmountofwaterCarboncarbon(100millionm3/a)emissionintensity(10,000t(kgCO2-eq/m3)CO2)WaterWaterreclamation0.08129.60_reclamationtreatment0.1458.2311.93systemStormwatertreatment-Stormwater-895.61systemTotalThecarbonemissionaccountingresultsofthecity'swatersectorsshowthatthetotalcarbonemissionofthewatersupplysystemis6,012,600tCO2-eq.Thetotalcarbonemissionsofthewastewatermanagementsystem,waterreclamationsystem,andstormwatersystemare2,728,200tCO2-eq,96,000tCO2-eq,and119,300tCO2-eq,respectively.Thetotalcarbonemissionofthewholewatersectoris8,956,100tCO2-eqwithapercapitacarbonemissionofabout426kgCO2-eq.D.8.3EmissionreductionpathwayanalysisBasedontheanalysisofthetotalamountandcompositionofcarbonemissionsofthecity'swatersector,thewatermanagementdepartmentproposedsomecarbonemissionreductionpathwaysassummarizedbelow.D.8.3.1WatersavingTheannualpercapitawaterresourcesinthiscityisapproximately191m3,indicatingarelativelyscarcewaterresourcessituation.AccordingtotheStandardforUrbanDomesticWaterConsumption,theminimumwaterconsumptionforresidents'dailylifeshouldbeabove100L/(cad),andthereasonablewaterrequirementforimprovinglivingconditionsshouldbeabove150L/(cad).Currently,thecity'stotalresidentialdomesticwaterconsumptionis1.70billionm3/a,whichisabout221.8L/(cad),farexceedingtheabove-mentionedwaterconsumptionquotas.Itindicatesthatthereissignificantpotentialforwatersavinginthecity.Bysavingresidents'domesticwaterconsumption,theoperationburdenofthewatersupplysystemcanbereduced,leadingtoadecreaseinthetotalcarbonemissions.Additionally,optimizingthestructureofwatersourcesandprioritizingthereductionofhighcarbon-intensitywaterresourcecaneffectivelyreducecarbonemissions.Underscenarioofdifferentwater-savingpolicies,thecarbonemissionsofwatersupplyandwaterreclamationsystemareestimatedinaccordancewithChapter5,andtheresultsareshowninFigureD.3.213Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigureD.3Changesincarbonemissionsofwatersupplyandwaterreclamationsystemsunderdifferentwater-savingscenariosAccordingtoFigureD.3,awaterquotaof150L/(cad)ismorereasonableandcannotonlyeffectivelyreducethetotalcarbonemissionsofwatersupplyandreclaimedwatersystem,butalsomeettheneedsofresidentstoimprovelivingconditions.D.8.3.2Developmentofnon-traditionalwatersourcesForalongtime,thelocalsurfacewaterandgroundwaterresourcesofthecityhasbeenoverexploitedandexceededthesustainablelimits.Thecurrentsurfacewaterresourcereservationis665millionm3,whichisfarlowerthanthelong-termaveragereservationof1.772billionm3.Thegroundwaterresourcereservationis1.751billionm3,anddecreasedby5.2billionm3comparedwiththatinlastcentury,withawaterleveldeclineby10m.Ifnosolutionsareproposed,waterresourceswillbecomeanimportantconstraintontheurbandevelopment.Currently,thecityhasadoptedlong-distancewaterconveyanceandwastewaterreclamationtoobtainandsupplementlocalwaterresources.D.8.3.2.1WastewaterreclamationWastewaterreclamationreferstotheadvancedtreatmentofthesecondaryeffluentproducedbythewastewatertreatmentplants,whichundergoesfurthertreatmenteitheron-siteoroff-sitetoenhancethewaterqualityforrecyclingpurpose(Yietal.,2011).Generally,reclaimedwaterisnotrecommendedforportableuse,butitcanbeutilizedforindustrial,ecological,andagriculturalpurposes(Chenetal.,2013).Currently,therecoveryratioofrecycledwaterinthecityisapproximately62%.Increasingtherecoveryandutilizationofreclaimedwatercanalleviatetheproblemofwatershortageinthecity.Atthesametime,itcanalsooptimizethestructureofwatersupplysources,reducetheuseofhighcarbon-intensitywatersources,andeffectivelydecreasecarbonemissions.Basedondifferentscenariosofreclaimedwaterreuse,thecarbonemissionsofwatersupplyandwaterreclamationsystemareestimatedaccordingtoChapter5,andtheresultsareshowninFigureD.4.Itcanbeobservedthatawastewaterrecoveryratio214Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:Casestudiesof90%yieldsamorecost-effectiveandefficientcarbonemissionreduction,makingitmoreconducivetoachievingsustainabilitygoals.FigureD.4Changesintotalcarbonemissionsofwatersupplyandreclaimedwatersystemsunderdifferentreclaimedwaterrecoveryratesinacity.D.8.3.2.2RainwaterreuseRainwaterreusereferstothecollectionandtreatmentofrainwaterfortoiletflushing,greenirrigation,roadflushing,landscapewater(Leongetal.,2017),etc.Itcaneffectivelysolvethecurrentsevereproblemsofwaterresourceshortageandwaterenvironmentalpollution.Currently,thecity'sannualrainwaterutilizationisabout3×108m3,andtherainwaterreuserateisabout36.45%.Byreusingpartoftherainwater,thedrainagepressureofthewatersupplysystemandthestormwatersystemcanbereduced,leadingtoadecreaseincarbonemissions.Basedondifferentscenariosofrainwaterreuse,thecarbonemissionsofstormwatersystemareestimatedaccordingtoChapter5,andtheresultsareshowninFigureD.5.Withtheincreaseofthecity'srainwaterreuserate,thecarbonemissionreductionalsoincreases.215Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigureD.5Changesincarbonemissionsofrainwatersystemsunderdifferentrainwaterreuseratesinacity.D.8.3.2.3SeawaterdesalinationThecityislocatedatanareaapproximately300kmfarawayfromthenearestcoastline,whichprovidesaccesstoseawaterresourcesfordesalinationandsupplementingfreshwaterresources.Thecarbonemissionintensityofseawaterdesalinationisapproximately0.336kgCO2-eq/m3.Currently,thecityhasnotyetutilizedseawaterdesalinationasasourceoffreshwater.Byusingseawaterdesalination,localwaterresourceshortagecanbealleviated.Atthesametime,itcanalsooptimizethestructureofwatersupplysources,reducetheuseofhighcarbon-intensitywatersources,andeffectivelydecreasecarbonemissions.Basedondifferentscenariosofutilizingseawaterdesalinationtoprovidewatersource,thecarbonemissionsofthewatersupplyandwaterreclamationsystemcanbeestimated,andtheresultsareshowninFigureD.6.216Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesFigureD.6Changesincarbonemissionsofwatersupplyandreclaimedwatersystemsunderdifferentdesalinationwaterconsumptioninacity.Thecarbonemissionintensityofseawaterdesalinationanddistributionisslightlyhigherthanthatofgeneralsurfacewaterintakeandtreatment,especiallywhenthecityisfarawayfromcoastline(Martinez-Mateetal.,2018).Therefore,consideringthespecificgeographicalconditionsofacity,seawaterdesalinationshouldbeadoptedappropriately,anditsuseshouldbetargetedtowardsreducingthecarbonintensityofhigher-emissionwatersources,leadingtoanoptimizationofthewatersourcesstructure.D.8.3.3EnergyrecoveryfromwastewaterDomesticWastewaterisrichinenergysuchaschemicalandthermalenergytherecoveryofwhichcaneffectivelyoffsetthecarbonemissionsgeneratedintheprocessofwastewaterandsludgetreatment(Haoetal.,2015).D.8.3.3.1AnaerobicdigestionInthewastewatertreatmentplant,approximately50%ofthewastesludgeistreatedwithanaerobicdigestion,whiletherestisdirectlydisposedofinlandfills.Byincreasingtheanaerobicdigestionrateandrecoveringenergythroughdigestion,etc.,itispossibletooffsetapartofthecarbonemissionsofwastewatertreatment,andtheresultsareshowninFigureD.7.217Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigureD.7Changesintotalcarbonemissionsofsewagetreatmentplantsunderdifferentanaerobicdigestionratesinacity.D.8.3.3.2RecoveryofthermalenergyInthecity,theaverageoutdoortemperatureduringwinter(JanuarytoFebruarynextyear)is0℃,andtheindoorheatingstandardissetat18℃.Currently,naturalgasiswidelyusedforheating,withanaverageconsumptionofapproximately6.6m3/(m2d).However,wastewaterthermalenergyhasnotbeenusedforheatingpurpose.Theaveragetemperatureoftheeffluenttreatedbythecity'swastewatertreatmentplantsduringwinterisabout14℃.Byrecoveringthethermalenergyfromwastewater,itcanprovideheatingfornearbybuildings,therebyoffsettingthecarbonemissionsfromwastewatertreatment.Basedonotherengineeringcaseforwastewaterheatrecovery,theemissionreductionof1.76kgCO2-eq/m3ofwastewatercanbeachieved.Thus,underthescenarioofdifferentwastewatertemperatureheatenergyrecoveryratiosforheatingduringwinter,thecarbonemissionsareshowninFigureD.8:218Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestCarbonaccounting:CasestudiesFigureD.8Changesincarbonemissionsofsewagetreatmentplantsunderdifferentheatingratiosofrecycledsewageheatinacityinwinter.Itcanbeobservedthatbyutilizingwastewaterthermalenergyforheatingduringwinter,itispossibletooffsetuptonearly70%ofthetotalannualcarbonemissions,demonstratingitssignificantemissionreductionpotential.Furthermore,thewastewaterheatenergycanalsobeusedforcoolingduringsummer.Therefore,itcanfurtheroffsetthecarbonemissionsgeneratedbywastewatertreatmenttoachievea"carbonneutral"orevena"carbonnegative"state(Haoetal.,2019a).D.8.3.4CarbonsinkfromgreenstormwaterspaceBothplantsandsoilinthegreenspacecansequestercarbondioxide(Lessmannetal.,2022).Assumingatotalareaof100m2forthegreenfacility,theunitcarbonsequestrationraterangesfromapproximately1.60to2.23kgCO2-eq/(m2a).Therefore,thecarbonsequestrationtotalofthespongecity’sgreenfacilityisapproximately160.2to222.6kgCO2-eq/(100m2a).219Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixECarbonemissionreductionpotentialoftypicaltechnologiesE.1EMISSIONREDUCTIONPOTENTIALOFWASTEWATERTHERMALENERGYRECOVERYAwastewatertreatmentplantislocatedatShanghai,withatreatmentcapacityof28,800m3/d.Itadoptswatersourceheatpumptechnologywiththeeffluentastheheatsource.Theextractedandrecoveredheatenergyisprovidednearbyresidentsheatingduringwinterandcoolingduringsummerforanareacovering1,800m2.Thesystemcanreplacetraditionalcoal-firedorelectricity-consumingheatingandcoolingmode,resultinginareductionincarbonemissions.TheheatingoperationtakesplacefromDecembertonextFebruary,andthecoolingoperationoccursfromJulytoSeptember.ThespecificoperationmodeandparametersareshowninFigureE.1.FigureE.1Operationparametersofwastetemperatureheatenergyrecoveryinthecasesewagetreatmentplant.221Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorThetheoreticalextractionpotentialofwastewaterthermalenergyinthecaseplantusingawatersourceheatpumpiscalculatedasfollows.𝐴=𝑄×𝑐×∆𝑇(E.1)𝐴(E.2)𝐴𝐻=𝐴+𝐶𝑂𝑃−1𝐻𝐴(E.3)𝐴𝐶=𝐴−𝐶𝑂𝑃+1𝐶𝛿−𝛼(E.4)𝑀𝐶𝑂2,𝐻=𝐴×(1+𝛼∙𝐶𝑂𝑃)×𝐸𝐹×10−6(E.5)𝐻𝐴𝐴𝑀𝐶𝑂2,𝐶=𝐶𝑂𝑃−𝐶𝑂𝑃/3600×𝐸𝐹𝐷𝐶,𝐴𝐶Where,𝐴—Heatenergyextractedfromwastewater,kJ𝑄—Wastewaterflow,m3𝑐—Specificheatcapacityofwater,4.2×103kJ/m3∆𝑇—Extractheatenergytemperaturedifference,℃𝐴𝐻—Thetheoreticalheatthatcanbeobtainedwhenheatenergyisextractedfromwastewaterforheating,kJ𝐶𝑂𝑃𝐻—Theenergyefficiencyratioofthewatersourceheatpumpduringheatingisusually1.77~10.63,generally3.5𝐴𝐶—Thecoolingcapacitythatcanbeobtainedwhenextractingheatenergytowastewaterforcooling,kJ𝐶𝑂𝑃𝐶—Theenergyefficiencyratioofthewatersourceheatpumpduringcoolingisusually2.23~5.35,generally4.8𝑀𝐶𝑂2,𝐻—Thecarbonemissionreductionamountfromexternalheating,kgCO2-eq𝛼—Energyefficiencyofcoal-firedheating,55%~70%,generally60%𝛿—Energyefficiencyofcoal-firedthermalpowergeneration,theaveragelevelis33%𝐸𝐹—Coalcombustionemissionfactor,96.10kgCO2-eq/GJ𝑀𝐶𝑂2,𝐶—Thecarbonemissionreductionamountfromexternalcooling,kgCO2-eq𝐶𝑂𝑃𝐶,𝐴—Energyefficiencyratioofairsourceheatpumprefrigeration,3.4𝐸𝐹𝐷—Emissionfactorofelectricity,kgCO2-eq/kWh3600—1kWh=3,600kJThecalculationsshowthatinthecasewastewatertreatmentplant,thetheoreticalheatenergyextractioninwinteris604.8GJ/d,resultinginacarbonemissionreductionof50.65tCO2/d.Theemissionreductionintensityis1.76kgCO2-eq/m3ofwastewater,leadingtoatotalreductionof4,558.4tCO2-eqduringwinter.Insummer,thewastewatercouldaccept846.72GJ/denergytocooltheoffice,resultinginacarbonemissionreductionof13.43tCO2-eq/d.Thecarbonemissionintensityis0.47kgCO2-eq/m3ofwastewater,yieldingacarbonemissionreductionof1,208.6tCO2-eqduringsummer.Infull-scaleproject,duetoheatlossinpipelinetransmissionandmultipleheatpumpconversionsintheenergydistributionofheating/coolingareas,theactualannualenergyrecoveryis15,582GJ.Theannualcarbonreductionisabout1,109tCO2-eq,reducingthecoalconsumptionof423.28t.222Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestItisevidentthatthethermalenergyrecoverypotentialofwastewaterforheatingishigherthanthatforcooling(Brunoetal.,2009).Itcanbeexplainedbythecurrentheatingandcoolingmethods.Ontheonehand,thereisasignificanttemperaturedifferencebetweentheindoorandoutdoorenvironmentinwinter,andtheefficiencyofairsourceheatpumpsisrelativelylow.Therefore,coalburningordirectconversionofelectricityisgenerallyusedtoobtainheatenergy.Insummer,thetemperaturedifferencebetweenindoorandoutdoorenvironmentisrelativelysmall,andtheenergyefficiencyofairsourceheatpumpforcoolingishigher.Consequently,extractingthermalenergyforheatingpurposeyieldsmorecarbonemissionreduction.Chinageneratedatotalof57.14billiontonsofdomesticwastewaterin2020.Basedontheabovecalculation,ifwatersourceheatpumpsarewidelyimplementedthroughoutsociety,3.0×108GJofheatenergycanbegenerated,equivalenttoareductionofabout25.1416milliontCO2-eq.Andduringthecoolingperiod(calculatedas3months),4.2×108GJcoolingenergycanbegenerated,equivalenttoareductionofabout67.1395milliontCO2-eq.Intermsofeconomicbenefits,wastewatersourceheatpumpsalsohaveadvantages.TakeawastewatertreatmentplantinQingdaoasanexample,theplantprovidesheatingtothe40,000m2ofsurroundingresidentialbuildingsduringwinterheatingperiod,whichlastsabout140dayseachyear.Theplanthasatreatmentcapacityof200,000m3/d,andtheaveragewastewatertemperatureinwinteris13°C.Afterheatexchangebytheheatpump,thehotwaterwithanaveragetemperatureof46°Cisobtained,whichisthendeliveredtotheendoftheusers.Theinitialinvestmentfortheentirewastewatersourceheatpumpsystem,includingtheequipment,pumpstations,andpipelinenetwork,is14.8millionyuan.Incomparison,thetraditionalcoal-firedboilersystemcost11.6millionyuanforinitialinvestment.However,duringtheoperationforheating,theactualannualoperatingcostofthewastewatersourceheatpumpisabout420,000yuan,whiletheactualannualoperatingcostofthecoal-firedsystemisabout1.3millionyuan.Itisevidentthatalthoughtheinitialinvestmentofthewastewatersourceheatpumpishigh,theoperatingcostislow.Afterabout4years,theinvestmentofheatpumpsystemcanberecoveredandhigherincomecanbeobtainedthereafter.Noteworthyisthattherearemanychallengesintheimplementationprocessofthewastewatersourceheatpumpproject,suchashigherinitialinvestmentcost,whichposesdifficultiesinfundraisingandobtainingloansforeconomicactivities.ThereisalackofpolicysupportforconnectingthewastewatersourceheatpumptothemunicipalheatingpipenetworkinChina,resultinginalackofproperutilizationofrecoveredheatenergy.Therefore,thewastewatersourceheatpumpprojectstillneedstoovercomethesechallenges.E.2EMISSIONREDUCTIONPOTENTIALOFSOLARPOWERGENERATIONIn2013,theStateCouncilofChinaissuedSeveralOpinionsoftheStateCouncilonPromotingtheHealthyDevelopmentofthePhotovoltaicIndustry(StateCouncilofChina，2013),whichclarifiedtheactionplantovigorouslydevelopthedistributedphotovoltaicpowergenerationmarket.Theplanaimedtofullydevelopthesurfacespaceofthevariousbuildingsandstructuresindifferentindustriesandsupporttheinstallationofsmall-scaledistributedphotovoltaicspowersystem.Withtheadoptionofeconomicsubsidies,theinstalledcapacityofdistributedphotovoltaicpowergenerationinChinahasgreatlyincreased.Forwastewatertreatmentplants,therearemultiplestructureswithalargespace.Andtheyaregenerallylocatedatthesuburbareawithouthigh-risebuildings,withgoodsunlightcondition,whichmakeswastewatertreatmentplantsgoodconditionsforinstallingphotovoltaicequipment.Sincethepioneeringinstallationofphotovoltaicpanelinwastewatertreatmentplantsin2014,atotalof22223Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorplants(20wastewatertreatmentplantsand2watertreatmentplants)havecompletedtheinstallationofphotovoltaicpanelsandstartedtoself-generateelectricity.Toclearlydemonstratethepotentialofphotovoltaicpowergenerationtechnologyincarbonemissionreductionofurbanwatersectors,thissectionpresentsananalysisofthecurrentfull-scaleprojectsinChina.AsshowninTableE.1,thetreatmentcapacityofwastewatertreatmentplantsadoptingphotovoltaicpowergenerationisbetween0.6and1.7milliont/d.Theinstalledphotovoltaicpanelsaredistributedontheheadspaceofsecondarysedimentationtanksandthebiologicaltanks,withanannualpowergenerationcapacitybetween6and22millionkWh.Sincethefootprintsofthecasewastewatertreatmentplantsarenotavailable,consideringthecorrelationbetweenthetreatmentcapacityandthefootprint,theannualsolarpowergenerationisnormalizedtothetreatmentcapacity.TheresultsshowthatthepotentialelectricitygenerationperunitoftreatedwaterinChinaisapproximately21.31kWh/m3(FigureE.2).Itcanbeappliedfordeterminationofthephotovoltaicpowergenerationprojectsinotherwastewatertreatmentplants.Combiningwiththeelectricityconsumptiondataofthecasewastewatertreatmentplants,thephotovoltaicpowergenerationcancoverabout4%to37%oftheelectricityconsumption(FigureE.3),withanaverageofapproximately15%.Intermsofthecarbonemissionreduction,photovoltaicpowergenerationcanreducecarbonemissionsbyanaverageofabout9.7%bysavingexternalelectricityconsumption(baseemissionincludingelectricityconsumptionofwastewatertreatmentplantsanddirectCH4andCO2emissions,excludingchemicalsconsumption,fossilcarbonemissionsandtransportationemissions,FigureE.4).Amongthese,WangxiaoyingWastewaterTreatmentPlantcanachieveacarbonemissionsreductionofabout25.8%throughphotovoltaicpowergeneration,whilesomeindividualwastewatertreatmentplantscanonlyreducecarbonemissionsby1.7%.Intermofreturnoninvestment(themagnitudeoftheannualreturnoninvestment),theapplicationofphotovoltaictechnologyinallwastewatertreatmentplantscanreduceelectricityandcosts,andcanachieveaninvestmentreturnofapproximately1.3%to7.9%.Inaddition,thelasttwocasesinTableE.1representtheapplicationofphotovoltaicpanelsinwatertreatmentplants,whichcancontributetoabout17%to19%ofenergyconsumption.Itisimportanttoemphasizethat,asshowninFigureE.2,theelectricitygenerationintensity(electricitygenerationperunitofwater)ofwastewatertreatmentplantswithinstalledphotovoltaicpanelsisrelatedtothecapacityofwastewatertreatmentplants.FigureE.2showsthatthesolarpowergenerationintensityofrelativelysmall-scalewastewatertreatmentplantsissignificantlylowerthantheaveragelevel.Consideringthattheelectricityconsumptionintensityofsmall-scalewastewatertreatmentplantsisoftenhigherthantheaverage,theapplicationofphotovoltaicpanelsshouldconsidertherelationshipbetweenemissionreductionandinvestment.224Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestFigureE.2Correlationbetweenpowergenerationandsewagetreatmentcapacityofphotovoltaicpowergenerationequipmentthatcanbeinstalledinsewagetreatmentplants(dataareobtainedfromcases1to18inTableE.1).FigureE.3Annualphotovoltaicpowergeneration,totalpowerconsumption,back-feedingpowerratioandcarbonemissionreductionratioofthecasesewagetreatmentplant.225Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorFigureE.4Investmentcost,costsavingandinvestmentreturnratioofphotovoltaicpowergenerationequipmentinsewagetreatmentplant.226Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestTableE.1Photovoltaicpowergenerationcaseofwastewatertreatmentplant.SerialDesignAreaofElectricityElectricityInvestmentCostCarbonTotalcarbonCarbonnumbertreatmentphotovoltaicgenerationconsumptioncost1savings2emissionemissions3emissioncapacitypanel(10,000(10,000kWh/a)(10,000kWh/a)(10,000(10,000reduction(10,000tCO2-reduction(10,000m3/d)yuan)(10,000tCO2-eq)potential(%)m2)yuan)eq)130111,200.003,197.406,285.612,686.40237,630.00922,611.4125.7628018.172,200.008,526.4013,809.463238,880.54472,285.002,691,874.2717.54360151,900.006,394.809,89412,763.50407,882.502,433,636.9516.76472.26143.82746.061,047.61,245.2530,874.56224,287.7413.765121136.731,278.96878.821,300.9929,352.51412,473.257.12633.5\174.923,570.431,112.41,653.0834,638.531,100,128.663.157362.42400.003,836.882,421.123,955.8885,870.001,173,975.537.3185\94.24532.90582894.7418,661.88168,613.2111.07991127.00959.22672.211,317.8825,149.18281,091.048.951025\532.902,664.502,554.985,896.81105,527.52957,579.1011.021130\160.143,197.401,396.82,164.3131,711.721,067,142.382.971240\120.104,263.201,047.61,623.1223,782.801,422,856.511.671315\86.751,598.70756.61,172.5017,178.67539,572.473.181425\323.532,664.502,121.393,036.4869,453.80903,468.307.69156\119.84639.48774.061,120.6123,731.31212,931.6211.141620\62.252,131.60407.4533.0413,363.51677,797.521.9717263.28359.142,771.081,908.963,718.7671,118.69790,592.568.9918205.94649.862,700.003,454.176,729.13128,688.52833,643.5615.4419170\1,284.0018,118.607,886.112,529.50254,264.10\\2015\85.701,598.7001,409.7620,180.21\\2120\411.412,117.002,677.23,538.1788,319.44\\221004.4511.103,000.002,677.25,331.737101,210.58\\1Consideringcostandoperationandmaintenanceinvestment(operationandmaintenanceinvestmentiscalculatedas20%ofcostinvestment);2Consideringthegovernment'ssubsidies;3Consideringthecarbonemissionsofelectricityconsumptionofwastewatertreatmentplants,andthetotaldirectcarbonemissionsofCH4andN2Oinwastewatertreatmentplants;41~20casesarewastewatertreatmentplants,21~22casesarewatersupplytreatmentplants.227Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorE.3COMPARISONOFCARBONEMISSIONSBETWEENVACULUMDRAINAGESYSTEMANDGRAVITYDRAINAGESYSTEMAsmallvillageislocatedatNorthwestofChina,withanareaofapproximately86hm2andapopulationof1,137people.Thevillageissituatednearimportantculturalrelicssites.Toprotectculturalrelics,theexcavationdepthofpipesislimitedtonomorethan30cm.Ifthetraditionalgravitydrainagesystemisused,thepipeslopecanonlyfollowthenaturalroadslopeandadopttheminimumgradient,resultinginpoorhydraulicconditionsinthepipeandincreasedchangesofblockageandcarbonemission.Asanalternativesolution,thevacuumdrainagesystemisnotrestrictedbytheterrainanddoesnotrequireahighexcavationdepth,makingitsuitableforareaswithculturalheritagepreservation(Milsometal,.1979).Finally,thevillageadoptsavacuumdrainagesystem.TableE.2Summaryofparametersoftwodrainagesystems.ProjectValueProjectValueServingpopulation1000mWastewaterflow600peoplePipelinelength30mg/LWastewaterCOD350m3/dTN0.003Diameter26minutes200mg/LFlowrate4m/sGravitydrainagesystem3kWh/dDailyelectricityconsumptionDN200SlopeDiameter0.65m/sHydraulicretentionHydraulicretentiontimetime1.5kWh/dVacuumdrainagesystemDN150Flowrate4.2minDailyelectricityconsumptionTheCH4emissionintensityofthevacuumdrainagesystemisaccordingtoEquation(E.6).𝐴(E.6)𝐶𝐸𝑆𝐶𝐻4=𝛾×[𝑉]×𝐻𝑅𝑇×28Where𝐶𝐸𝑆𝐶𝐻4—CH4emissionintensityofvacuumdrainagesystem,kgCO2-eq/m3𝛾—SpecificCH4releaserate,kg/m2h,defaultis5.24×10-5HRT—Theresidencetimeofwastewaterinthesewer,h28—GlobalwarmingpotentialofCH4,defaultis28kgCO2-eq/kgCH4AccordingtothecalculationmethodprovidedinthisGuidelines,thecarbonemissionsgeneratedfromthetwodrainagesystemsimplementedinthevillagewerecalculatedandsummarizedinTableE.3.228Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestTableE.3Comparisonofcarbonemissionaccountingresultsoftwodrainagesystems.EmissionDailyEmissionactivitiesAccountingintensityemissionsProportionMethods(kgCO2-(kgCO2-0.22%eq/m3)eq/d)39.91%37.63%GravityDrainageSystem22.24%DirectFossilCO2Equation(5-10~11)3.8×10-50.01-dischargeCH4Equation(5-14~16)0.0072.430.05%21.94%N2OEquation(5-18~19)0.00662.2915.44%62.57%IndirectElectricityEquation(5-2)0.00391.35-emissionsconsumptionTotal-0.0176.09VacuumDrainageSystemDirectFossilCO2Equation(5-10~11)6.2×10-60.01dischargeCH4Equation(E-6)0.00270.94N2OEquation(5-18~19)0.00190.66IndirectElectricityEquation(5-2)0.00772.67emissionsconsumptionTotal-0.01234.28Basedonthecalculationresults,itcanbeobservedthatthemainsourceofcarbonemissionsfromthegravitydrainagesystemisdirectemissions(77.76%),andthemainsourceofcarbonemissionsfromthevacuumdrainagesystemisindirectemissionsfromelectricityconsumption(62.57%).Despitethehigherelectricityconsumptionofthevacuumdrainagesystemcomparedtothegravitydrainagesystem,thedirectcarbonemissionsthegreenhousegasaresignificantlyreduced.Therefore,thecarbonemissionsofthevacuumdrainagesystemarelowerthanthoseofthetraditionalgravitydrainagesystem,makingitaviablecarbonemissionreductiontechnologyforwastewatercollectionsystem.Inadditiontothecarbonreductionpotential,thevacuumdrainagesystemsalsohaveseveraladvantagesinvariousaspects.Comprehensiveevaluationandratingswereconductedforbothgravitydrainagesystemandvacuumdrainagesystemsintermsofregionalplanning,technology,environment,socialfactorsandeconomicinvestment,respectively,asfollows.•Intermsofregionalregulations,considerationsareprimarilygiventothetopographicalstructure,landuseconditions,andtransportationissues,etc.Additionally,priorityisplacedonthepreservationofarchaeologicaldiscoveries.•Intermsoftechnicalaspects,considerationsareprimarilygiventoflexibilityintheconstructionphase,systemperformance(consideringpossiblechangesinthefuture),processcomplexity,professionalknowledgerequirements,andoperationalsafety.•Intermsoftheenvironmentalimpacts,considerationsaregiventothegeologicalconditionsofthearea,andthecompatibilitywiththelocalecosystem.•Intermsofthesocialdimension,considerationsincludepublicacceptance,publichealthconcerns,anduserengagementduringsystemoperation.•Intermsoftheeconomicstandard,considerationsincludeinstallationcosts,operationcostsandmaintenancecosts.229Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorTheevaluationresultsareshowninTableE.4.Thevacuumdrainagesystemisbetterthanthatofthegravitydrainagesystemforthefollowingreasons:i)theareahasaflatterrain,whichissuitableforvacuumconveyance.b)thecostsofthevacuumdrainagesystemaremuchlowerthanthoseoftraditionalgravitydrainagesystem.c)therearestillmanyancientculturalrelicsthathavenotbeenexcavatedinthearea,requiringflexiblehandlingduringexcavatingwork.Overall,thevacuumdrainagesystemissuitableforacomplexundergroundsituationwithouttheneedfordeepexcavation.TableE.4Comprehensiveevaluationresultsofgravityandvacuumdrainagesystem.StandardGravitydrainageVacuumdrainagesystemsystemRegionalPlanning26.0331.35Non-economicTechnology22.0825.42criteria(inscore)Environment24.130.3116.622.7Societytotalscore88.81109.78EconomicStandardInstallationcost5.38×1063.66×106(inEuros)Operatingcosts1.65×1052.92×104Maintenancecost7.41×1043.88×104Comprehensivescore0.791.00230Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixFReportingprotocolXXCarbonemissionsaccountingreportReportingentity(seal):YearmonthdayReportingyear:Prepareddate:231Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorReportingutilityinformationUtilitynameIndustryOrganizationcodecodeIndustryTelephoneFaxAddressTelephonePostcodeLegalrepresentativeFaxMailaddressBranchleadersTelephoneFaxCarbonemissionTelephoneFaxmanagementPostcodedepartmentNeworexpandedfacilities(comparedtothepreviousyear):DirectorReducedordownsizedfacilities(comparedtopreviousyear):E-mailLiaisonE-mailMailaddressThemainproductorserviceAccountingandreportingboundary232Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestReportingprotocolCarbonemissionsreportScope(IPCC(2Type(ISO14064-1:CarbonCarbonTotalannual019)2018)emissionemissionscarbonactivities(tCO2-eq)emissions(tCO2-eq)DirectgreenhouseDirectgreenhousegasemissionsfromgasemissionsactivitieswithinthe……managementboundaryoftheCarbonsinkaccountingentity……IndirectGHGIndirectGreenhouseemissionsduetoGasEmissions-electricity,steam,ElectricityandHeatheating/coolingConsumptionsources……IndirectGreenhouseOtherindirectGasEmissions-greenhousegasTransportemissionscausedIndirectGreenhousebytheactivitiesofGasEmissions-theaccountingMaterialInputsand…subjectbutoutsideServices…themanagementIndirectGreenhouseboundaryoftheGasEmissions-accountingsubject,AssetandBy-…suchaspurchasedProductDisposal1…consumables,wasteIndirectGreenhousedisposalGasEmissions-Other……Total:Carbonemissionsintensity(tCO2-eq/m3):233Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorWastewatertreatmentplant-directemissionreportingMonthWaterWastewatertreatmentSludgetreatment(treatmentmethod:)volume/m3WaterqualityindexEmissionfactorGreenhousegasSludgeindexEmissionfactorGreenhousegasemissionsemissionsBOD5FossilTotalSludgesourceCO2FossilsludgefossilFossilsourcesourcesourceratioCO2SludgeCO2CO2TOCratioTNN2ON2ON2OCH4SludgeindexN2OCH4TOCCH4TotalTotalGreenhousegasTotalCH4GreenhousegasWaterqualityindexEmissionfactorsludgeemissionsEmissionfactoremissionsBOD5FossilSludgesourceCO2FossilTOCSludgeFossilsourcefossilsourceratioCO2sourceCO2CO2TNN2ON2ORatioN2OCH4CH4TOCCH4TotalN2OTotalCH4234Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestAppendixFReportFormatTemplateMaterialinventoryinducingindirectemissionABCDE.S/NMaterialAnnualconsumption(t,Emissionfactor(kgIndirectemissionstypetenthousandm3,MWh)CO2/t)(tCO2)235Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestDownloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestReferencesAghabalaeiV.,NayebH.,MardaniS.,TabeshniaM.andBaghdadiM.(2023).Minimizinggreenhousegasesemissionsandenergyconsumptionfromwastewatertreatmentplantsviarationaldesignandengineeringstrategies,AcasestudyinMashhad,Iran.EnergyReports,9,2310-2320.AhmedF.,SharizalA.A.M.,PalaniandyP.andShaikF.(2022).Areviewonapplicationofrenewableenergyfordesalinationtechnologieswithemphasisonconcentratedsolarpower.SustainableEnergyTechnologiesandAssessments,53,102772.AhnJ.H.,KimS.,ParkH.,RahmB.,PagillaK.andChandranK.(2010).N2Oemissionsfromactivatedsludgeprocesses,2008-2009,resultsofanationalmonitoringsurveyintheUnitedStates.EnvironmentalScience&Technology,44,4505–11.AlexisA.(2021).CarbonfootprintofFinnishwastewatertreatmentplants.AaltoUniversity.AmjadiH.,KhashehchiM.andSoltaniJ.(2020).Experimentalinvestigationandnumericalsimulationofaninlinelow-headmicrohydroturbineforapplicationsinwaterpipelines.IETRenewablePowerGeneration,14,3209-3219.AshrafiO.,YerushalmiL.andHaghighatF.(2014).Greenhousegasemissionandenergyconsumptioninwastewatertreatmentplants,impactofoperatingparameters.Water,42(3),207-220.AyazM.,NamaziM.A.,DinM.A.u.,ErshathM.I.M.,MansourA.andAggounee.-H.M.(2022).Sustainableseawaterdesalination,Currentstatus,environmentalimplicationsandfutureexpectations.Desalination,540,116022.BaoZ.,SunS.andSunD.(2016).AssessmentofgreenhousegasemissionfromA/OandSBRwastewatertreatmentplantsinBeijing,China.InternationalBiodeterioration&Biodegradation,108,108-114.BellandiG.,PorroJ.,SenesiE.,CarettiC.,CaffazS.,WeijersS.,NopensI.andGoriR.(2018).Multi-pointmonitoringofnitrousoxideemissionsinthreefull-scaleconventionalactivatedsludgetanksinEurope.WaterScience&Technology,3-4,880-890.BellucciF.(2011).GreenhouseGasEmissionsfromThreeFull-ScaleMetropolitanWastewaterReclamationPlants.UniversityofIllinoisatChicago.BengtssonS.,BloisM.,WilénB.M.andGustavssonD(2019).Acomparisonofaerobicgranularsludgewithconventionalandcompactbiologicaltreatmenttechnologies.EnvironmentalTechnology,40(21),2769–2778.BisinelladeFariaA.B.,SpérandioM.,AhmadiA.andTiruta-BarnaL.(2015).Evaluationofnewalternativesinwastewatertreatmentplantsbasedondynamicmodellingandlifecycleassessment.WaterResearch,84,99-111.237Downloadedfromhttp://iwaponline.com/ebooks/book-pdf/1367724/wio9781789064223.pdfbyguestGuidelinesforCarbonAccountingandEmissionReductionintheUrbanWaterSectorBlombergK.,KosseP.,MikolaA.,KuokkanenA.,FredT.,HeinonenM.,MulasM.,LübkenM.,WichernM.andVahalaR.(2018).DevelopmentofanExtendedASM3ModelforPredictingtheNitrousOxideEmissionsinaFull-ScaleWastewaterTreatmentPlant.EnvironmentalScience&Technology,52(10),5803-5811.BrottoA.C.,KligermanD.C.,deSouzaPiccoliA.anddeMelloW.Z.(2010).Emissaodeoxidonitrosodeestacaodetratamentodeesgotodelimosativadosporaeracaoprolongada-estudopreliminar.Quimicanova,33(3),618-623.BrunoJ.C.,Ortega-LópezV.andCoronasA.(2009).Integrationofabsorptioncoolingsystemsintomicrogasturbinetrigenerationsystemsusingbiogas,Casestudyofasewagetreatmentplant.Appliedenergy,86(6),837-847.BuonocoreE.,MellinoS.,DeAngelisG.,Liu,G.andUlgiati,S.(2016).Lifecycleassessmentindicatorsofurbanwastewaterandsewagesludgetreatment.EcologicalIndicators,94,13-23.CaiK.,WangH.,WangJ.,BaiJ.,ZuoJ.,ChanK.,LaiK.andSongQ.(2023).MitigatinglifecycleGHGemissionsofbuildingsectorthroughprefabricatedlight-steelbuildingsincomparisonwithtraditionalcast-in-placebuildings.Resources,ConservationandRecycling,194,107007.CamposJ.L.,Valenzuela-HerediaD.,PedrousoA.,ValdelRíoA.,BelmonteM.andMosquera-CorralA.(2016).Greenhousegasesemissionsfromwastewatertreatmentplants,minimization,treatment,andprevention.JournalofChemistry,2016,3796352.ChaiC.,ZhangD.,YuY.,FengY.andWongM.S.(2015).CarbonfootprintanalysesofmainstreamwastewatertreatmenttechnologiesunderdifferentsludgetreatmentscenariosinChina.Water,7(3),918-938.ChenW.,LuS,JiaoW.,WangM.andChangA.C.(2013).Reclaimedwater,Asafeirrigationwatersource?EnvironmentalDevelopment,8,74-83.ChenX.M.,MielczarekA.T.,HabichtK.,AndersenM.H.,ThornbergD.andSinG.(2019).AssessmentofFull-ScaleN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