传统的和倒置A2O工艺的比较外文翻译

ComparisonofconventionalandinvertedA²/Oprocesses:PhosphorusreleaseanduptakebehaviorsAbstractTwofull-scalesystemsoperatedinparallel,aconventionalA2/Osystemconsistingofanaerobic,anoxicandoxiccompartmentsinsuccessionandaninvertedsystemconsistingofanoxic,anaerobicandanoxiccompartmentswithoutinternalrecycle,werecomparedintermsoftheirphosphorusremovalperformance,withanemphasisonphosphate(P)releasebehaviors,usingbothoperationaldataandsimulationresults.Theinvertedsystemexhibitedbetterlong-termphosphorusremovalperformance(0.2±0.3vs.0.7±0.7mg/L),whichshouldbeattributedtothehigherPreleaserate(0.79vs.0.60kgP/(kgMLSS·day))inthenon-aeratedcompartments.ThePreleaseoccurredinboththeanoxicandanaerobiccompartmentsoftheinvertedsystem,resultinginmoreefficientPrelease.Althoughtheabundancesofthe‘CandidatusAccumulibacterphosphatis’populationinthetwosystemswerequitesimilar((19.1±3.27)%and(18.4±4.15)%ofthetotalmicrobe(DAPIstainedparticles)populationintheinvertedandconventionalsystems,respectively,byfluorescenceinsituhybridization(FISH)),thehigh-concentrationDAPIstainingresultsshowthattheabundancesofthewholepolyphosphateaccumulatingorganisms(PAOs)intheaerobicendswerequitedifferent(theaverageratiosofthepoly-Pgranulestototalmicrobes(DAPIstainedparticles)were(45±4.18)%and(35±5.39)%.BoththeoperationaldataandsimulationresultsshowedthattheinvertedsystemretainedmoreabundantPAOpopulationsduetoitsspecialconfiguration,whichpermittedefficientPreleaseinthenon-aeratedcompartmentandbetterPremoval.1Materialsandmethods1.1TargetedsystemsandwatersamplinghesewagetreatmentplantstudiedconsistsofaconventionalandinvertedA2/Osystem,respectively,eachofwhichhasatreatmentcapacityof200,000m3/day.TheinfluentdistributionratiooftheinvertedA2/Owasstable(30%totheanoxictankand70%totheanaerobicone).Thesludgereturnratiowasapproximately100%forbothsystemsduringthesamplingperiod.ThedetaileddescriptionsofthetwosystemsareshowninFig.1andTable1.AsshowninTable1,theconventionalsystemwasalittlelargerthantheinvertedone.FromFebruarytoJuly2009,mixedliquorsamplesweretakenweeklyfromthetwoendsandthemiddleofeachunitforwaterqualitymonitoring,andactivatedsludgewascharacterizedmonthlybytakingsamplesfromtheendsoftheaerobicandanaerobicunits.Aftersampling,sampleswereimmediatelytransportedtothelaboratoryforanalysis.ThedeterminationofCOD,biologicaloxygendemand(BOD),mixedliquorsuspendedsolids(MLSS)andphosphatespeciesfollowedstandardprocedures(APHA,1998).Routinedataduring20072009werekindlyprovidedbytheplant.Theoperatingconditions,suchassludgeretentiontime(SRT)andinfluentdistributionwerealsomonitored.1.2FISHanalysisandhigh-concentrationDAPIstaining.TheFISHanalysiswasconductedaccordingtoAmannetal.(1995).riefly,activatedsludgesampleswaterfixedfor3hrwith4%paraformaldehydeat4°Candstoredina1:1(V/V)mixtureofphosphate-bufferedsaline(PBS,pH7.4)andethanolat–20°C.Followingson-(PBS,pH7.4)andethanolat–20°C.Followingsonicationoniceforabout3min,a3-μLsamplewasicationoniceforabout3min,a3-μLsamplewasplacedinthewellsofaslideandimmobilizedfor3hr.Theslideswerethendehydratedfor5minusing50%,80%and98%ethanol,respectively.1.3ActivatedsludgemodelThefull-scaleplantmathematicmodelwasconstructedbyAQUASIMsoftware(EAWAG,licensenumber:251basedonASM2d(Henzeetal.,2000).WholebiologicaltankswereconsideredasCSTR,whilethesettlingcompartmentwassetasanideallocationforsolid-liquidseparationwithoutbiochemicalreaction.ASM2dwithoutchemicalprecipitationofphosphatewasemployedtomodelthebiochemicalreactionsinbothsystems.Sensitivitythebiochemicalreactionsinbothsystems.Sensitivityanalysiswasusedforparametersestimation.TheeffluentfromtheaeratedgritchamberwasanalyzedaccordingtothestandardDutchSTOWAguidelinesforwastewatercharacterization(RoeleveldandvanLoosdrecht,2002).ThesolubleCODfractionwasmeasuredafterflocculationwithZn(OH)2andfiltrationwitha0.45μmfiltermembrane(Millipore,USA)asrecommendedintheSTOWAprotocol.TheweeklymeasuredtotalCODwasfractionatedintomodelcomponentsasshowninTable22.PreleaseanduptakebehavioursVariationsofPconcentrationsalongthereactorlengthsweredeterminedfromFebruarytoJuly,2009,andtheresultsareshowninFig.2.Becausethetwosystemsaredifferentinsizes,thelengthpercentage(theratioofthedistancebetweentheinletandthesamplingpointtothetotallengthofthesystem)wasusedtorepresentthereactorlength.AsshowninFig.2,thePreleaseoccurredintheanoxiccompartment(average,(21.9±8.2)Pmg/L),andcontinuedintheanaerobicone(average,(20.2±9.1)Pmg/L)oftheinvertedA2/Osystemtakingintoconsiderationthedilutionratiosinthetworeactors(dilutionratio:1.3intheanoxiccompartmentand2.0intheanaerobicone).ThenthePuptakeoccurredalongtheaerobiccompartment.Ontheotherhand,thePreleaseoccurredmainlyintheanaerobiccompartmentintheconventionalsystem,withaPconcentrationof(19.02±0.96)Pmg/L.ThePconcentrationintheanoxicunitwasalmostconstantat(4.61±0.96)Pmg/L,whichwaslowerthanthatintheanaerobiccompartmenttakingintoconsiderationthedilutionfactorof2.5.ThusthePreleasestoppedinthisreactor.3ConclusionsThephosphorusremovalperformanceofafull-scaleinvertedandaconventionalA2/Osystemreceivingthesamemunicipalwastewaterw