sdarticle(3)

Wat.Res.Vol.35,No.16,pp.3968–3976,2001#2001ElsevierScienceLtd.AllrightsreservedPrintedinGreatBritain0043-1354/01/$-seefrontmatterPII:S0043-1354(01)00132-4BIOLOGICALNITROGENREMOVALWITHENHANCEDPHOSPHATEUPTAKEINASEQUENCINGBATCHREACTORUSINGSINGLESLUDGESYSTEMDAESUNGLEE1,CHEOKJEON1andJONGMOONPARK2*1LaboratoryofEnvironmentalBiotechnology,SchoolofEnvironmentalEngineering,PohangUniversityofScienceandTechnology(POSTECH),San31,Hyoja-dong,Pohang,Kyungbuk,790-784SouthKoreaand2LaboratoryofEnvironmentalBiotechnology,DepartmentofChemicalEngineering,DigitalInformationCenterforEnvironmentResearch,PohangUniversityofScienceandTechnology(POSTECH),San31,Hyoja-dong,Pohang,Kyungbuk,790-784SouthKorea(Firstreceived28January2000;acceptedinrevisedform28February2001)Abstract}Simultaneousbiologicalphosphorusandnitrogenremovalwithenhancedanoxicphosphateuptakewasinvestigatedinananaerobic–aerobic–anoxic–aerobicsequencingbatchreactor((AO)2SBR).Significantamountsofphosphorus-accumulationorganisms(PAOs)capableofdenitrificationcouldbeaccumulatedinasinglesludgesystemcoexistingwithnitrifiers.Theratiooftheanoxicphosphateuptaketotheaerobicphosphateuptakecapacitywasincreasedfrom11%to64%byintroducingananoxicphaseinananaerobic–aerobicSBR.The(AO)2SBRsystemshowedstablephosphorusandnitrogenremovalperformance.AverageremovalefficienciesofTOC,totalnitrogen,andphosphoruswere92%,88%,and100%,respectively.Itwasfoundthatnitrite(upto10mgNO2�–N/l)wasnotdetrimentaltotheanoxicphosphateuptakeandcouldserveasanelectronacceptorlikenitrate.Infact,thephosphateuptakeratewasevenfasterinthepresenceofnitriteasanelectronacceptorcomparedtothepresenceofnitrate.Itwasfoundthaton-linesensorvaluesofpH,ORP,andDOweresomehowrelatedwiththedynamicbehavioursofnutrientconcentrations(NH4+,NO3�,andPO43�)intheSBR.Theseon-linesensorvalueswereusedasreal-timecontrolparameterstoadjustthedurationofeachoperationalphaseinthe(AO)2SBR.Thereal-timecontrolledSBRexhibitedbetterperformanceintheremovalofphosphorusandnitrogenthantheSBRwithfixed-timeoperation.#2001E