AO工艺与分段进水两种生物脱氮工艺的比较研究英文

JournalofSoutheastUniversity(EnglishEdition)Vo.l24,No.4,pp.528-531Dec.2008ISSN10037985Comparativestudyoftwobiologicalnitrogenremovalprocesses:A/OprocessandstepfeedingprocessZhuGuibing1,2PengYongzhen1,3WangShuying3MaBin1(1SchoolofMunicipalandEnvironmentalEngineering,HarbinInstituteofTechnology,Harbin150090,China)(2StateKeyLaboratoryofEnvironmentalAquaticChemistry,ResearchCenterforEcoEnvironmentalSciences,ChineseAcademyofSciences,Beijing100085,China)(3KeyLaboratoryofBeijingWaterQualityScienceandWaterEnvironmentRecoveryEngineering,BeijingUniversityofTechnology,Beijing100022,China)Abstract:Twobiologicalnitrogenremovalprocessesarecomparedintheaspectofnitrogenremova,lprocessoperationandenergysaving.Resultsshowthatwhenthereturnedsludgeratiois50%oftheinflowrate,thestepfeedingprocessachievesover80%totalnitrogen(TN)removalefficiency,buttheTNremovalefficiencyoftheA/Oprocessisonly40%.Moreover,filamentoussludgebulkingcanbewellrestrainedinthestepfeedingprocess.Giventheconditionsofareturnedsludgeratioof100%andanitrifyingliquorrecycleratioof200%,theTNremovalefficiencyis7832%intheA/Oprocess,butthesludgevolumeindex(SVI)valueincreasesto143mL/g.Inthestepfeedingprocess,theSVIisonly944mL/gwhentheTNremovalefficiencyreaches811%.ThestepfeedingprocesshasdistinctadvantagesovertheA/Oprocessintheaspectsofpracticability,nitrogenremovalandoperatingstability.Keywords:activatedsludge;biologicalnitrogenremova;lA/Oprocess;stepfeedingprocess;efficiencyReceived20080226.Biographies:ZhuGuibing(1979),male,doctor;PengYongzhen(correspondingauthor),male,doctor,professor,[e-mail]:TheProjectofScientificResearchBaseandScientificInnovationPlatformofBeijingMunicipalEducationCommission(No.PXM2008-014204-050843),theProjectofBeijingScienceandTechnologyCommittee(No.D07050601500000),theKnowledgeInnovationProgramoftheChineseAcademyofSciences(No.RCEESQN200706),theSpecialFundsforYoungScholarsofRCEES,CAS.Citation:ZhuGuibing,PengYongzhen,WangShuying,eta.lComparativestudyoftwobiologicalnitrogenremovalprocesses:A/Oprocessandstepfeedingprocess[J].JournalofSoutheastUniversity(EnglishEdition),2008,24(4):528531.Thenitrogenandphosphorusremovaltechnologyamiedateutrophicationcontrolhasbeenthefocusinthefieldofbiologicalwastewatertreatment.Phosphorusinthewastewatercanberemovedbyconventionalbiologicalphosphorusremovalprocessescombinedwithchemicalsedmientation,whilenitrogencanonlyberemovedeffectivelyandeconomicallywithbiologicalmethods[1].Nowadays,inmostcountries,especiallyinChina,about70percentofthewastewatertreatmentplantsuseanA/Oprocessforbiologicalnitrogenremoval[2].IntheA/Oprocess,theinfluentfirstentersananoxicdenitrificationzonetodenitrify,miprovingthenitrogenremovalefficiency.Moreover,mostorganiccarbonintheinfluentisbiodegradedbydenitrificationbacteria,whichcanshortentheaerobicdurationtmie.ButbecauseofconstructionoftheA/Oprocess,theNOXNconcentrationintheeffluentequalsthatinnitrifyingliquorrecycling,whichexplainsthatthetotalnitrogen(TN)removalefficiencyoftheA/Oprocesscannotbehigh.Astepfeedingactivatedsludgeprocesswasdevelopedasameansofcircumventingsomeoftheproblemsoftheplugflowreactor.Itisafactthatinthestepfeedingprocesssomestagesofdenitrificationnitrificationreactorsoperateinseries.Thismodificationhasthefollowingadvantages:1)Regardingprocessoperation,itelmiinatestheinternalnitrifyingliquorrecycle.Nitrifyingliquorineveryaerobiczonedirectlyentersthenextanoxiczone;2)Regardingtreatmentefficiency,itmiprovestheTNremovalefficiency.Ifthenitrificationanddenitrificationperformcompletelyateachstage,theTNconcentrationisonlydeterminedbythenitrateconcentrationproducedinthepreviousstage;3)Regardingreactionrate,theorganicsubstancesdistributealongthereactors,whichlessensthedifferencesbetweentheoxygensupplyratesandoxygenconsumptionrates;4)Regardingactivatedsludgeloading,theprmiaryeffluentisintroducedbystepfeedandthereturnedsludgeenterstheheadofthereactor,whichgivesrisetoasuspendedsolidsgradientalongthereactorandmiprovesthetreatmentcapacityofthesystem.SeveralwastewatertreatmentplantsinAmericaandJapanhavebeenextended,renewedorretrofittedasstepfeedingprocessessoastoenhancenitrogenremova.lHowever,moststudieshaveconcentratedontheoreticalanalysisandcomputersmiulation[34].Somepracticalexperiencesaredrawnfromoperationsofanextended,renewedorretrofittedconventionalactivatedsludgeprocess[57].Butseldomhastheliteraturereportedaboutextending,renewingandretrofitting.ThereisnoresearchaboutthecomparisonbetweentheA/Oprocessandthestepfeedingprocess.1MaterialandMethods11PilotplantTheprocessstudiedisabiologicalwastewatertreatmentplantbasedonanA/Oandastepfeedingprocess,asshowninFig.1.Thetwochannelcuboidreactorhasadmiensionof800mm220mm500mmmadeofplexiglass.Thetypeoffinalclarifierisuprightwithaworkingvolumeof30L.Theflowratesofinfluent,internalcycleandretunedsludgearecontrolledbyperistalticpumps(LangeZ2515300M),respectively.Forthepurposeofmaintainingplugflowandconcentrationgradient,theaerobicandanoxiczonesineachstageareseparatedbyclapboardsasdifferentjointcompartments.Thevolumeratioofthean