modern wwtp design a conventional wwtp (cas/sbr) the aeration system of the activated sludge system...

2018

ModernWWTPDesignSLUDGEPRODUCTION&ENERGYEFFICIENCYMATHIASBLANCHE(WWW.BLANCHE-WATERENGINEERING.DE)

WORKING PAPER ON WASTEWATER TREATMENT PLANT DESIGN – BCM2018

©AllrightsreservedbyBLANCHEWATERENGINEERING-BCM•www.blanche-waterengineering.de 2

TableofContent

1 FUTUREREQUIREMENTSFORWASTEWATERTREATMENTPLANTDESIGN............................3

1.1 ReduceSludgeProduction................................................................................................3

1.2 PhosphorousRecovery.....................................................................................................5

1.3 EnergyEfficiencyandOPEX...............................................................................................7

2 WASTEWATERTREATMENTPLANTOFTHEFUTURE.............................................................11

2.1 RequirementsforWWTPDesign.....................................................................................13

FiguresandTables

Fig.1-1FlowchartforCASforBNRinaccordanceDWA-A131.............................................................4Fig.1-2Flowchartformulti-stageprocessforBNRandIFASprocess...................................................4Fig.1-3Recommendedapplicationsforsewagesludgestabilization,acc.DWA-M368........................5Fig.1-4Potentialreclamationsources...................................................................................................6Fig.1-5OPEXDistribution......................................................................................................................7Fig.1-6SSOTR(Supratec).......................................................................................................................7Fig.1-7Averagepowerdemandforwastewatertreatmentandspecificpowerconsumption.............8Fig.1-8Dropofannualpowerconsumptionandsludgecakeproductionafterchangefromaerobictoanaerobicdigestionfor28.800P.E.designcapacity,acc.DWAT1/2015,A.1.......................................9Fig.1-9Anaerobicdigesterwithintegratedgasholder(www.lipp-system.de/www.mifratis.de).........9Fig.1-10LayoutWWTP10.000P.E.withseparateanaerobicdigestion.............................................10Fig.1-11Compactdigestersystemdesign(Source:www.zwt.de)......................................................10Fig.2-1Massbalanceforconventionalsludgetreatment(Pinnekamp,KA2018(65),Nr.3)..............12Fig.2-2Grossmassbalanceforoptimizedsludgetreatment(Pinnekamp,KA2018(65),Nr.3).........12Fig.2-3OverviewWWTPdesignrequirements,acc.NSMS.................................................................16



1 FutureRequirementsforWastewaterTreatmentPlantDesign

TheenforcedimplementationofCouncilDirective91/271/EECforUrbanWasteWaterTreatment(UWWTD)setsoutadditionalrequirementsforfutureWWTPdesigninordertocomplywithstateoftheartprocesstechnology,regarding:

• Advancedsludgetreatmentforreducedsludgeproduction;

• Phosphorousrecovery;

• Energyefficiency.

Itshouldbenotedthattheserequirementsarecloselyrelatedandmayberealizedstepbystepduringthelife-cycleofnewlydesignedandcompletedWWTP’sandshallbeconsideredforup-gradeandrehabilitationofexistingWWTP’s.

1.1 ReduceSludgeProduction

Sludgeproduction(primarysludge+wasteactivatedsludge)ischieflydependantontheadoptedwastewaterandsludgetreatmentprocesstechnologyofaWWTP.

• Primary sludge (PS) production depends on the required wastewater treatment effi-ciency, i.e.whether primary treatment is applied for secondary treatment or tertiarytreatmentatbigWWP’s;

• SecondaryorWASproductiondependsonthebiologicaltreatmentprocess,i.e.applica-tionoftheattachedgrowthorsuspendedgrowthprocess,orcombinationsthereof;

• Digestedsludgeproductiondependsonthedegradationefficiencyofthesludgestabili-zationprocessandpotentialprocessoptimisations.

Forthepurposeofminimizedprimarysludgeproductionprimarysedimentation(PS)shallbeap-pliedonlyincaseanaerobicdigestionisplannedforsludgetreatment.Insuchcaseitshouldbeplannedformaximizedseparationefficiency(SRT≥2,5h)incaseofsecondarytreatmentandascoarseSedimentation(SRT≤0,5h)orCOD-exfiltration1incaseoftertiarywastewatertreatmentinordertomaintainthereadily,solubleCODfractionforbiologicaltreatment.

Reductionofsecondary&tertiarysludgeproduction(WAS)canbeachievedbyconsiderationoftheattachedgrowthprocessforsecondarywastewatertreatment(TF2,RBC3)andbycombina-tionsofthesuspendedgrowthprocess(suchasCAS4)withtheattachedgrowthprocessincaseoftertiarywastewatertreatment.

SuchcombinationsincludeadvancedwastewatertreatmentprocessvariantsofMBBR5,IFAS6orNereda7.Inaddition,itshouldbehighlightedthatmulti-stagetreatmentprocesses,suchasstep-

1Exfiltrationoftheinert,non-dissolvedCOD-fractionbymicro-sieves(http://www.huber.de/hu-ber-report/ablage-berichte/screens/huber-supplies-a-process-system-as-replacement-for-the-primary-settling-tank.html)

2TF=TricklingFilter3RBC=RotationBiologicalContactors4CAS=ConventionalActivatedSludge(System)5MBBR=MovingBedBiofilmReactor6IFAS=IntegratedFixed-FilmActivatedSludge(CAS+MBBR)7Nereda®=modifiedCASbasedonaerobicgranulation,MarkvanLoosdrechtofDelft,University



feed(cascade)orthemodifiedmultiplestepBardenphoprocessaremoreefficientatlowerWASproduction,comparedwithCAS,duetothecascadeeffect.

Reviewofmanyfeasibilitystudiesforon-goingWWTPdesignsshowsthatinmanycasesthesimpleprocessofconventional,single stage activated sludge (CAS) forBNR,inacc.withthe“plugflow”orA2OprocessorSBRprocess,areadoptedforBNR (biological nutrient removal, acc.Art.4oftheUWWD).

Fig.1-1FlowchartforCASforBNRinaccordanceDWA-A131

Moreadvancedwastewater-treatmentoptions for reducedWAS-productionarepresentedbythe following flow-charts, based on the activated sludge process or combinations of the sus-pendedgrowthandattachedgrowthprocessapplications.

Fig.1-2Flowchartformulti-stageprocessforBNRandIFASprocess

ThespecificWASproductionwillbereducedduetotheadaptedbiocenosisofmulti-stagetreat-mentprocessesorduetoattachedgrowthatMBBRandIFAS.Comparedwithsingle-stageCASanoverallreductionoftheWASproductioninarangeof5-20%canbeassumed8,dependingontheadoptedprocessvariant.

TheprinciplesfordigestedsludgereductionaremainlytargetingondisintegrationofWASand/orDS(digestedsludge)inordertoenhancehydrolysisofnutrientsandorganiccarbon(COD)whichareenclosedinthecellmembranesoftheorganicmatter(VDS).Thus,increasingtheefficiencyofVDS-decompositionbysome10-30%whichresultsinreducedSRT(HRT,digestiontime)and

8https://www.iwapublishing.com/news/reduction-sludge-production-wastewater-treatment-plants



increaseddigestergasproduction.However,sludgedisintegrationmayincreasethepowerde-mandoftheactivatedsludgesystemduetoincreasedback-chargefromsludgewaterandsuper-natantwhichisbalancedbytheincreaseddigestergasproduction.

Moreadvancedprocessesoptionsmayconsiderhydrothermaloxidation(HTC)orcombinationsofmesophilanaerobicdigestionwiththermophilicaerobicdigestionaswellas2-phase(high-rate)anaerobicdigestion.

Inaddition,thefinalsludgequantitycouldbereducedbypost-degradationofresidualorganicmatterbysludgehumificationandcomposting.Sludgehumificationinreedbedsshallbeconsid-eredasadditionalprocessstageforsmallWWTP’sbecauselong-termstoragewillfurthermorereducetheorganicmatterofdigestedsludgeandsignificantlyreducethesludgevolume.

Thereductionpotentialoftheoverallspecificdigestedsludgeproductionbyapplicationofmod-ern,commonlyapprovedprocesstechnologycanbeachievedbycombinationsoftheattached&suspendedgrowthprocessvariantsforbiologicalwastewatertreatmentaswellasfarreachingapplicationofanaerobicsludgedigestioncombinedwithsludgedisintegration.

Thefollowinggraphillustratestherecommendedrangeofapplicationofdifferentsludgetreat-menttechnologies:

Anaerob,mesophilorthermophiledigestion

Dualstabilization

Aerobic-thermophilestabilization

Simultaneousaerobicstabilization

Composting

Fig.1-3Recommendedapplicationsforsewagesludgestabilization,acc.DWA-M3689

ThereviewmanyfeasibilitystudiesforongoingWWTPdesignsshowsthatmainlyconventionalsludgetreatmentprocessoptionsforsimultaneousaerobicsludgestabilizationbyextendedaer-ationandsingle-stageanaerobicsludgedigestion(withbiogasutilizationbyCHP)areadopted.

Consultantsanddesignersshallbeencouragedtoconsidermodern,stateoftheartprocesstech-nologiesforboth,wastewaterandsludgetreatmentinordertoreducethespecificsludgeproduc-tionasfaraspossible.

1.2 PhosphorousRecovery

ThemainpotentialsourcesforP-reclamationfromseweragesludgearerawsecondary&tertiarysludge(WAS),digestedliquidsludge(DS),dewateredsludgeanditssupernatantaswellasdrysludgeandsludge-ash(incaseofmono-incineration).

9AdvisoryleafletDWA-M368„BiologicalStabilisationofSewageSludge“,2014•DWADeutscheVereinigungfürWasserwirtschaft,AbwasserundAbfalle.V.•D53773Hennef•ISBN:978-3-944328-60-7



Fig.1-4Potentialreclamationsources

Variousprocess technologieshavebeenevolved in recent yearswhichare in the commercialphase,now.Twomaintechnologiesareavailable:

• P-extractionfromtheliquidphase,and

• P-recyclingfromsludgeash.

PhosphorusrecoveryshallbeincludedinWWTPdesignshallbeduetothefactthattheaccesstothisresource,whichismostessentialforfutureagriculturalproduction,mustbeassuredforthenextgeneration!

• ThewastewatertreatmentprocessoptionsshallconsiderP-removal(EBPR+CPR);

• Sludge treatment shall consider future process options for P-reclamation from liquidsludge(i.e.spacereservationsandpossibilitytobeincludedintotheprocess);

• SludgemanagementanddisposalshallavoidthelossofPhosphorousrequiringmono-landfillofdriedsludgeorsludgeash;

• Inter-regional (inter-communal)sludge incinerationfacilitieswithP-recovery fromashshallbeconsideredonthelongterm.

PhosphorousrecoveryattheWWTPwillreducethefinalsludgequantitiesaccordingly(bysome5%)andisultimatelyrequiredforthenextgenerationinordertomakesuretodayscroprates!

© Fraunhofer

ABWASSERBEHANDLUNG UND P-ELIMINATION

Zulauf

P-Vorfällung P-Simultanfällung P-Nachfällung

Belebungsbecken Nachklärung Sand-/Fettfang

Vorklärung

Maschinelle Entwässerung Faulturm

Abgabe in Vorfluter

Verbrennung

PS RS

ÜS

SW

FS



1.3 EnergyEfficiencyandOPEX

PowerconsumptionforwastewaterandsludgetreatmentaswellassludgedisposalcostsarethedrivingcostfactorsofOPEXforindividualWWTP’s.

Inmostcasestheannualcostsforsludgedisposal are almost equal to annualpowercostsandmayreach50-60%ofthetotalWWTP-Opex.

(Example235.000P.E.:CASwithanaero-bic digestion and CCHP; dewateredsludge to mono-incineration at WWTPwithash-disposaltolandfill).

Fig.1-5OPEXDistribution

Powercostsaredependingonthespecificpowerconsumptionofthewastewatertreatmentpro-cesswhereassludgetreatmentanddisposalcostsaredependingonthespecificsludgeproduc-tionoftheindividualWWTP.

InmanyEUaccessionstates,thepowermarkethasbeenfullyliberalizedbutfutureprivatizationshouldbetakenintoconsiderationwithregardontheenormousinvestmentsnecessaryfornet-workmodernizationandreplacementofoutdatedpowerplants.OnEUaveragetheaveragein-dustrialpowercostsincreasedbyapprox.20%dduringan8-yearhorizon.

It canbeassumed that inmanySouth-EasternEUMemberStatesandWesternBalkanStatescurrentpowertariffsforbothprivatehouseholdsandindustrialconsumerswillincreaseaccord-ingly,whichjustifiesconsiderationofenergyefficiencymeasuresforWWTPdesign.

Improvementofenergyefficiencytargetsontheefficiencyoftheaerationsystemsaswellasonthebenefitofself-generated(electrical)powerafteranaerobic,mesophilicsludgedigestion.

AtaconventionalWWTP(CAS/SBR)theaerationsystemoftheactivatedsludgesystem(blowerswithmembraneaeratorsorsurfaceaerators)isthebiggestconsumerwhichcausesapprox.60-70%ofthetotalpowerconsumption.

Optimization shall consider multiplestageprocessvariantsandapplicationofhighefficientaerationsystems(OTE≥3,5-4,2kgO2/kWh).Plate-typeaeratorswithaspecificoxygenintake capacity of SSOTR ≥ 22-25 gO2/m3

NxmET [at4-8m3N/h/ea.)shallbe

appliedinordertoincreasetheefficiencyoftheaerationsystem.

Fig.1-6SSOTR(Supratec)



Optimisedspecificdigestergasproduction(gasyield)isrequiredforhighefficientutilizationofdigestergasreuseforenergy&heatrecoverybyCHP/CCHP10.Theaveragespecificpowerpoten-tial forconventionalbiogasreuse isapprox.15kWh/P.E./yr. forconventionalsludgedigestionplantsandupto22,5kWh/P.E./yr.forfuture,optimizedconceptionofWWTP’s.

Asanexample,itshouldbenotedthatduringsummermonthexcessheat,whichisneitherusedforrawsludgeheatingorthermalsludgedrying,andwhichisusuallywastedbytheemergencycoolersoftheCHP-engines,mightbeutilizedforcoldproductionbyabsorptionchillers(CCHP,trigeneration) inorder toprovidecoolingenergy for theentireair-conditioning systemof theWWTP(PLC/MCC’Sandbuildings).

Thefollowinggraphillustratestheaveragepowerdemandforwastewatertreatmentandpro-videsanoverviewaboutthespecificpowerconsumptionbasedonDWA-benchmarking.

Fig.1-7Averagepowerdemandforwastewatertreatmentandspecificpowerconsumption

ThespecificpowerdemandfornewWWTP’sshalltargetonlessthan25-30kWh/P.E./yr.(Ger-many≤23,5kWh/P.E./yr.).

Currentdevelopmentsintheprocessengineeringindustrypromotetheapplicationofseparateanaerobicdigestionmorewidely,alsoforsmallWWTP’s(≥10.000P.E.).TheDWAthemededitionT1/201511providesindeeptechnologicalandeconomicassessmentofthetopicaswellascasestudiesfromrecentyears.

BesidesincreasedtreatmentperformanceandoptimizedenergyefficiencyOPEXaresignificantlyreduced,furthermorethecarbonfootprintofwastewatertreatmentcouldbeminimized.Incom-parisonwith theprocessofanaerobicdigestion theprocessofaerobicsludgestabilizationre-quiresahighersludgeage12andadditionalaerationcapacity13forseparateorsimultaneousaer-obicsludgestabilization.Byapplicationofanaerobicdigestion,thebioreactorvolumeandpowerconsumption(foraeration)willbesignificantlyreduced.

Self-generatedpowerfromdigestergasutilization(CHP/CCHP)mightreducetheoverallspecificpowerdemandfromsome60kWh/P.E./yr.tolessthan30kWh/P.E./yr.

10CCHP-Trigeneration(https://www.clarke-energy.com/gas-engines/trigeneration)11DWAT1/2015SludgeDigestionorSimultaneousStabilizationforSmall&MiddleSizedWWTP’s12SRTaerob=22-25daysinsteadofSRTanaerob=10-15days13BODLoadappr.2,5kgDO/kgBOD5insteadof1,2kgDO/kgBOD5

DARKHAN WASTEWATER MANAGEMENT PROJECT

B. Design Considerations – Consultants Assessment

Benchmarking of Specific Power Demand

Approx. 60 - 70 % Power Demand for Aeration System

Average Distribution of Power Demand for WWTP‘s

Target Value for the Specific Power Demand below 30 kWh/P.E./yr. ç High Efficient Aeration Systemç Sludge Digestion & CCHP

� Process Design Target: Energy Efficiency = Low Operation Cost (OPEX)

Ø State of the Art Development's (Energy Efficiency)

Target ≤ 30 kWh/P.E./yr.

Best Practice and Consultants Recommendation



Fig.1-8Dropofannualpowerconsumptionandsludgecakeproductionafterchangefromaerobictoanaerobicdigestionfor28.800P.E.designcapacity,acc.DWAT1/2015,A.1.

ForcasestudyA.2fromDWAT1/2015thetotalpowerdemandcouldbereducedbymorethan50%aftertheprocessmodificationsin2010.

Thespec.sludgeproductiondecreasedfrom70gDS/P.E./dto45gDS/P.E./dimprovingthede-waterabilityofthedigestedsludgeatreducedflocculationaidconsumption,reducingthetrans-portationanddisposalcosts,accordingly.

Thefollowingpicturesareshowingcompactsolutionscomprisingready-madedigesterswithin-tegratedgas-storage:

Fig.1-9Anaerobicdigesterwithintegratedgasholder(www.lipp-system.de/www.mifratis.de)

WWTPdesign fornewwastewater treatmentplantsor refurbishmentandupgradeofexistingfacilitiesshallconsiderapplicationofanaerobicdigestionwithdigestergasutilizationfordesigncapacitiesabove20.000P.E.Commonlyapprovedtechnologyisavailableatcompetitivemarketprice.



ThefollowingpresentsanexampleofamodernWWTP(10.000P.E.)designedfortertiarywaste-watertreatment,usingthewell-establishedBiocos®process14(modifiedSBR)andseparatean-aerobicsludgedigestionwithdigestergasstorageandpowerrecoverybyCHP.

AnimationofaBiocos®WWTPdesignproposal.

Fig.1-10LayoutWWTP10.000P.E.withseparateanaerobicdi-gestion

Theoperationbuilding,comprisingadministrativeareas,mechanicaltreatmentandsludgede-wateringwithlateralsludgestorageareacanbeseenintheforeground.Theblowerhousewithgeneratorroomandtheanaerobicsludgedigesterwithgasholderareseenintheupperback-ground,whereastheBiocos®bioreactorswithsludgestorage,intermediatepumpingstationandbatchoperatedclarifiersareseeninthecenterbackground.

Anaerobic digester with twin-chamber, slow motion mixersandthermalwallcomponentac-tivationfordigesterheating.

Fig.1-11Compactdigestersystemdesign(Source:www.zwt.de)

ThespecificpowerconsumptionoftheWWTPiscalculatedwithlessthan20kWh/P.E./yr.andthespecificdigestedsludgeproductionisapprox.45gDS/P.E./d.

14http://www.zwt.deandhttp://www.hafi-group.com/en/technologies/overview.html



2 WastewaterTreatmentPlantoftheFuture

Thecarbonfootprint(GHG)ofwastewaterandsludgetreatmentcanbeminimizedbereductionofthespecificpowerconsumptionwhichrequiresfarreachingself-supplyofelectricityandheatproducedbyCHPand/orCCHPfromdigestergasutilization.

Besidesvariousoptionsforwastewatertreatmentprocessoptimizationconcerningrawsludgeproductionandfarreachingapplicationofanaerobicsludgetreatmentprocessesanadditionalprocessforpre-treatmentoffeedsludgeorrecirculationsludgebysludgedisintegrationshallbeappliedformiddlesizedandbigWWTP’s.SuchtypeofWWTP’swillhaveahigherpowerdemandduetofuturesludgedryingrequirements.

CurrentresearchforfutureandadvancedWWTPconception15targetsondigestergasyieldopti-mizationduetosidestreamrejectwater(supernatant)treatmentbydeammonification16withMAP17precipitation,or strippingofAmmonia (NH3)which significantly reduces thepower re-quirementofbiologicalwastewatertreatment.OngoingresearchconcernssubstitutionofAm-moniaremovalfromtheconventionalprocessofNitrification/DenitrificationwiththeprocessofDeammonificationinordertominimizetheWWTPfootprint,overallpowerconsumptionatre-ducedWASproduction(IFAS,MBBR,Nereda)butincreaseddigestergasproductionforhighen-ergyrecovery.However,full-scaleimplementationofsuchadvancedprocessvariantsisnotex-pectedinthenearfuturebutshouldbetakenintoconsiderationforbigWWTP’swhichmightbesubjecttophasedimplementation.

ThefollowingshallbeconsideredforfutureWWTPdesign:

• AnaerobicselectorforWASsludgefeed(digester)plusseparateWASthickening;

• Intensified, anaerobic,mesophil sludgedigestion forWWTP’s ≥ 20.00018 P.E.withdi-gestergasutilizationbyCHP;

• Intensified, anaerobic, mesophil (or thermophile) sludge digestion for WWTP’s ≥60.00018P.E.withsludgedisintegration(ultrasound)anddigestergasutilizationbyCCHP;

• SludgedisintegrationforWWTP’s≥100.00018P.E.byultrasound,thermaldisintegrationorthermalhydrolysisandincasesludgedisinfectionisrequired;

• Multi-stage, intensified, anaerobic, mesophil (or thermophile) sludge digestion forWWTP’s≥250.00018P.E.withsludgedisintegrationandseparatesupernatanttreatment(Anammox19)afterCOD-exfiltration,withdigestergasutilizationbyCCHP.

ThefollowinggraphspresenttheCODandmassbalanceofsludgetreatmentwhichillustratestheoptimizationpotential for futureWWTPdesign that shall be considered for thedesignof bigWWTP’s≥250.000P.E.:

15FinalReport"WastewaterTreatmentPlantoftheFuture",TUMünchen,200916https://www.essde.com/en/demon/demon-process17MAP=Magnesia-Ammonium-Phosphate(NH4MgPO4·6H2O)=Struvite18Proposeddesigncapacitiesaresubjecttoadditionalleastcostanalysis19De-Ammonification:https://www.sswm.info/water-nutrient-cycle/wastewater-treat-ment/hardwares/semi-centralised-wastewater-treatments/anammox



Fig.2-1Massbalanceforconventionalsludgetreatment(Pinnekamp,KA2018(65),Nr.3)

Fig.2-2Grossmassbalanceforoptimizedsludgetreatment(Pinnekamp,KA2018(65),Nr.3)



2.1 RequirementsforWWTPDesign

NewlydesignedWWTP’sorupgradeofexistingWWTP’sshallconsiderstateoftheartprocesstechnology and latest developments and tendencies concerning sludge treatment and sludgemanagementinmarketleadingEU-MemberStates,whicharesummarizedasfollows:

Secondarywastewatertreatment(≤10.000P.E.):

• Conservativedeterminationofthedesigncapacity;

• Analyse wastewater composition (long-term) for inhibiting substances/heavy met-als/contaminantsforsludgequalitydeterminationduringWWTPconstruction;

• Primarysedimentationincaseofattachedgrowthwithanaerobicdigestion;

• AttachedgrowthorMBBRforsecondarywastewatertreatmentinmulti-laneapplication;

• Highefficientaerationsystems(platetypediffusers,SOTE>3,5-4,2kgO2/kWh)fortheactivatedsludgeprocess;

• ITbasedmonitoringofpowerconsumptionofindividualprocesssteps(energyefficiency,set-pointcontrol);

• Disinfectionofpurifiedeffluent(seemulti-resistant-germs);

• Rejectaerobicsludgestabilization(separateorextendedaeration)≥10.000P.E.

• Anaerobic,mesophilicsludgedigestionwithdigestergasutilizationbyCHP(simplecom-mercialsystemsolutions)incaseofattachedgrowth(withpre-sedimentation);

• Highefficientthermalinsulationofdigester(highdensitypolyurethanefoam,PUR)foroptimizedheattransitioncoefficients(slap≤0,25W/m2K;wall/roof≤0,16W/m2K)andminimizedemissionlosses;

• Extendedaerationforsimultaneoussludgestabilization(incaseofactivatedsludge);

• Sludgethickeningandposttreatmentinreedbeds,iflandisavailable;

• Liquid sludge transport to inter-communalSTC20 for sludgedewateringandadvancedsludgetreatment(≤5.000P.E.);

• Sludgedewateringandtransporttointer-communalSTCforadvancedsludgetreatment(sludgedrying,etc.).

Tertiarywastewatertreatment(>10.000P.E.):

• Conservativedeterminationofthedesigncapacity;

• Analyse wastewater composition (long-term) for inhibiting substances/heavy met-als/contaminantsforsludgequalitydeterminationduringWWTPconstruction;

• PrimarysedimentationorCOD-exfiltrationfortertiarytreatment(BNR);

• Bio-P(EBPR),pre-applied(plusCPR);

• Anaerobicselectorforreturnsludge(RAS)feed;

• Multi-lane and multi-stage (step-feed) process for biological wastewater treatment(BNR)bytheactivatedsludgeprocess;

20STC-SludgeTreatmentCenterprovidingsludgedryingpluspyrolysisormono-incineration.



• OptionalupgradeforcapacityextensionbyIFAS/MMBR(approx.+30%P.E.);

• Highefficientaerationsystems(platetypediffusers,SOTE>3,5kgO2/kWh)withfuzzylogicprocesscontrol;

• ITbasedmonitoringofpowerconsumptionofindividualprocesssteps(energyefficiency,set-pointcontrol);

• Disinfectionofpurifiedeffluent(multi-resistant-germs);

• AnaerobicselectorforWASsludgefeed(digester)plusseparateWASthickening;

• Extendedaerationforsimultaneoussludgestabilizationfordesigncapacities<10.000P.E.only;withsludgereedbedsforlong-termstorage(andpost-degradation),eventuallysludgedewateringandtransporttointer-communalSTCforadvancedsludgetreatment;

• Intensified,anaerobic,mesophil sludgedigestion forWWTP’s≥20.00018P.E.withdi-gestergasutilizationbyCHPatgross-powerdemandoftheWWTP≤30kWh/P.E./yr.andspec.sludgeproduction≤50g/P.E./d;

• Highefficientthermalinsulationofdigester(highdensitypolyurethanefoam,PUR)foroptimizedheattransitioncoefficients(slap≤0,25W/m2K;wall/roof≤0,16W/m2K)andminimizedemissionlosses;

• Intensified, anaerobic, mesophil (or thermophile) sludge digestion for WWTP’s ≥60.00018 P.E. with sludge disintegration (ultrasound) and digester gas utilization byCCHP21;

• SludgedisintegrationforWWTP’s≥150.00018P.E.byultrasound,thermaldisintegrationorthermalhydrolysisandincasesludgedisinfectionisrequiredatgross-powerdemandoftheWWTP≤25kWh/P.E./yr.andspec.sludgeproduction≤50g/P.E./d(85%-percen-tile);

• SolarorthermalsludgedryingdependingonWWTPdesigncapacityandheatbalanceforWWTP’s≥30.000P.E.(consideredasSTC);

• Multi-stage, intensified, anaerobic, mesophil (or thermophile) sludge digestion forWWTP’s≥250.000P.E.with(thermal)sludgedisintegrationandseparatesupernatanttreatment(Anammox22)afterCOD-exfiltration,withdigestergasutilizationbyCCHPatgross-powerdemandoftheWWTP≤25kWh/P.E./yr.andspec.sludgeproduction≤45g/P.E./d(85%-percentile);

• Advanced sludge treatment by dewatered sludge pyrolysis (or similar) forWWTP’s ≥60.00018P.E.withwastegasandwasteheatutilizationforsludgedrying(STC),granulardisposalatmono-landfill(eventuallydirectside-streamfertilizerapplication);

• Advancedsludgetreatmentfordrysludgemono-incinerationforWWTP’s≥250.000P.E.withwastegasandwasteheatutilizationforsludgedrying(STC),ashdisposalatmono-landfill;

• Drysludgeorashdisposalonlytomono-landfillforfutureP-reclamationbyurbanmin-ing.

21CCHP-Trigeneration(https://www.clarke-energy.com/gas-engines/trigeneration)22De-Ammonification:https://www.sswm.info/water-nutrient-cycle/wastewater-treat-ment/hardwares/semi-centralised-wastewater-treatments/anammox



Theaforementionedrequirementsaretargetingonreducedsludgeproduction,andaresumma-rizedinthefollowingtableconsideringthedifferentcategoriesandWWTPdesigncapacities:

Cat. Capacity[P.E.]

WastewaterTreatment

SludgeTreatment PowerConsumption

SludgeDisposal

a ≤2.000 SecondaryTreatmentPrimarysedimentation(Im-hofftank);Attachedgrowth(TF/RBC);Constructedwetland/reed.

Psychrophilicdigestion(Im-hofftank)

≤15-20kWh/P.E./yr.

LiquidsludgetransporttoSTC;Sludgereedbed.

b ≤10.000 SecondaryTreatmentPrimarysedimentationincaseofattachedgrowth;Attachedgrowth(TF/RBC);CASorMBBRwithextendedaeration/withoutpre-sedi-mentation.

Mesophilicanaerobicdiges-tion(attachedgrowth)withCHP;Simultaneousaerobicstabi-lization.

≤35-60kWh/P.E./yr.

LiquidsludgetransporttoSTC;Sludgereedbedforpost-stabiliza-tion.

c ≤50.000 SecondaryTreatmentPrimarysedimentation;Attachedgrowth(TF);CASorMBBR.

Mesophilicanaerobicdiges-tionwithCHP;Mechanicalsludgedewater-ing.

≤35-40kWh/P.E./yr.

DewateredsludgetransporttoSTC;Sludgereedbedforpost-stabiliza-tion.

TertiaryTreatmentCoarseSedimentation;Bio-P(EBPR)withanaerobicselector(plusCPR);AnaerobicselectorRASCASinmulti-laneandsin-gle-stageprocess;ConsiderIFAS/MMBR.

AnaerobicselectorWAS+mechanicalWASthickening;Intensified,anaerobic,mes-ophilicsludgedigestionforWWTP’s≥30.000P.E.withdigestergasutilizationbyCHP;Mechanicalsludgedewater-ing.

≤30kWh/P.E./yr.

DewateredsludgetransporttoSTC;

de

≤100.000≤150.000

CoarseSedimentationorCOD-exfiltration;Bio-P(EBPR)withanaerobicselector(plusCPR);AnaerobicselectorRASCASinmulti-laneandmulti-stageprocess;ConsiderIFAS/MMBR;ConsiderMBR;Effluentdisinfection.

AnaerobicselectorWAS+mechanicalWASthickening;Intensified,anaerobic,mes-ophilsludgedigestionwithdigestergasutilizationbyCCHP;Sludgedisintegration(≥100.000P.E.);Mechanicalsludgedewater-ing;Solarorthermalsludgedry-ing;Sludgepyrolysis(orsimilar).

≤25kWh/P.E./yr.

STCDrysludgedis-posaltomono-landfill;Granularutiliza-tionasfertilizer.

f ≤250.000 CoarseSedimentationorCOD-exfiltration;Bio-P(EBPR)withanaerobicselector(plusCPR);AnaerobicselectorRASCASinmulti-laneandmulti-stageprocess;ConsiderIFAS/MMBR;ConsiderMBR;Effluentdisinfection;MAPprecipitation;Separatesupernatanttreat-mentbyAnnamox.

AnaerobicselectorWAS+mechanicalWASthickening;Intensified,anaerobic,mes-ophilsludgedigestionwithdigestergasutilizationbyCCHP;Thermalsludgedisintegra-tionorthermalhydrolysis;Mechanicalsludgedewater-ing;Solarorthermalsludgedry-ing.

≤25kWh/P.E./yr.

STC/SMCDrysludgedis-posaltomono-landfill;Drysludgetomono-incinera-tion;Granularutiliza-tionasfertilizer.

g ≥250.000 CoarseSedimentationorCOD-exfiltration

AnaerobicselectorWAS+mechanicalWASthickening;

≤25kWh/P.E./yr.

STC/SMC



Cat. Capacity[P.E.]

WastewaterTreatment

SludgeTreatment PowerConsumption

SludgeDisposal

Bio-P(EBPR)withanaerobicselector(plusCPR);AnaerobicselectorRASCASinmulti-laneandmulti-stageprocess;ConsiderIFAS/MMBR;ConsiderMBR;Effluentdisinfection;MAPprecipitation;Separatesupernatanttreat-mentbyAnnamox.

SludgedisintegrationforWWTP’s≥100.000P.E.Multi-stage,intensified,an-aerobic,mesophilsludgedi-gestionwithdigestergasutilizationbyCCHP;Mechanicalsludgedewater-ing;Thermalsludgedrying;Drysludgemono-incinera-tion.

Ashdisposaltomono-landfill.

Fig.2-3OverviewWWTPdesignrequirements,acc.NSMS

ConsultantsandContractorsworkingondesignfornewWWTP’sorupgradeandrefurbishmentofexistingWWTP’sshallbeencouragedtoconsidermodern,stateoftheartprocesstechnologyforboth,wastewaterandsludgetreatmentinordertoreducethespecificsludgeproductionandenergyconsumptionoftheWWTPunderconsiderationofprovisionsforfuturePhosphorousrec-lamation.

modern wwtp design a conventional wwtp (cas/sbr) the aeration system of the activated sludge system...

Documents