Modeling-the-PAO–GAO-competition

ModelingthePAO–GAOcompetition:Effectsofcarbonsource,pHandtemperatureCarlosM.Lopez-Vazqueza,f,AdrianOehmenb,ChristineM.Hooijmansa,DamirBrdjanovicc,HuubJ.Gijzena,d,ZhiguoYuane,MarkC.M.vanLoosdrechtf,*aDepartmentofEnvironmentalResources,UNESCO-IHEInstituteforWaterEducation,Wesvest7,2611AXDelft,TheNetherlandsbCQFB/REQUIMTE,ChemistryDepartment,FaculdadedeCieˆnciaseTecnologia,UniversidadeNovadeLisboa,2829-516Caparica,PortugalcDepartmentofUrbanWaterandSanitation,UNESCO-IHEInstituteforWaterEducation,Wesvest7,2611AXDelft,TheNetherlandsdUNESCOOffice,Jakarta,UNESCOHouse,Jl.Galuh(II)No.5,KebayoranBaru,Jakarta12110,IndonesiaeAdvancedWastewaterManagementCentre(AWMC),TheUniversityofQueensland,St.Lucia,Queensland4072,AustraliafDepartmentofBiotechnology,DelftUniversityofTechnology,Julianalaan67,2628BCDelft,TheNetherlandsarticleinfoArticlehistory:Received13July2008Receivedinrevisedform6October2008Accepted7October2008Publishedonline1November2008Keywords:Enhancedbiologicalphosphorusremoval(EBPR)MetabolicmodelingMicrobialcompetitionVolatilefattyacids(VFA)Poly-b-hydroxyalkanoates(PHA)DefluviicoccusvanusabstractTheinfluenceofdifferentcarbonsources(acetatetopropionateratios),temperatureandpHlevelsonthecompetitionbetweenpolyphosphate-andglycogen-accumulatingorganisms(PAOandGAO,respectively)wasevaluatedusingametabolicmodelthatincorporatedthecarbonsource,temperatureandpHdependencesofthesemicroorgan-isms.ThemodelsatisfactorilydescribedthebacterialactivityofPAO(Accumulibacter)andGAO(CompetibacterandAlphaproteobacteria-GAO)laboratory-enrichedculturescultivatedonpropionate(HPr)andacetate(HAc)atstandardconditions(20�CandpH7.0).Usingthecalibratedmodel,theeffectsofdifferentinfluentHActoHPrratios(100–0,75–25,50–50and0–100%),temperatures(10,20and30�C)andpHlevels(6.0,7.0and7.5)onthecompetitionamongAccumulibacter,CompetibacterandAlphaproteobacteria-GAOwereevaluated.ThemainaimwastoassesswhichconditionswerefavorablefortheexistenceofPAOand,therefore,beneficialforthebiologicalphosphorusremovalprocessinsewag