Effect-of-prefermentation-on-denitrifying-phosphorus-removal

EffectofprefermentationondenitrifyingphosphorusremovalinslaughterhousewastewaterM.Merzoukia,b,N.Berneta,*,J.P.Delgene`sa,M.BenlemlihbaInstitutNationaldelaRechercheAgronomique,LaboratoiredeBiotechnologiedel�Environnement,AvenuedesEtangs,11100Narbonne,FrancebLaboratoiredeMicrobiologiedel�Environnement,Faculte´desSciencesDharMehraz,B.P.1796,Fe´s,MoroccoReceivedinrevisedform3November2004;accepted23November2004Availableonline20January2005AbstractAnanaerobic–anoxicsequencingbatchreactor(A2SBR)coupledwithafixed-bednitrificationreactorforsimultaneouscarbon,nitrogenandphosphorusremovalwasevaluatedusingslaughterhousewastewater.Whereasthetreatmentcouldnotbesuccessfullycarriedoutontherawwastewater,theprocessshowedverygoodnutrientremovalperformancesafterprefermentation.Therem-ovalsofCOD,N-NH4andP-PO4achievedwere99%,85%and99%,respectively.Theincreaseinvolatilefattyacid(VFA)andphosphateconcentrationsintheeffluentafterprefermentationmayexplainthehighlevelsofbiologicalcarbon,nitrogenandphos-phorusremovalobserved.Asimpleprefermentationis,therefore,necessarybutsufficienttoensuregoodperformancesoftheden-itrifyingenhancedbiologicalphosphorusremoval(EBPR)process.�2004ElsevierLtd.Allrightsreserved.Keywords:Anoxicphosphorusremoval;Enhancedbiologicalphosphorusremoval(EBPR);Sequencingbatchreactor(SBR);Fixed-bednitrification;Prefermentation;Slaughterhousewastewater;Volatilefattyacids(VFA)1.IntroductionEnhancedbiologicalphosphorusremoval(EBPR)isbasedontheselectiveenrichmentofbacteriaaccumulat-ingpolyphosphate,obtainedinaprocesswithacycleofalternatinganaerobicandaerobicphases.Asanalterna-tivetothisprocessforbiologicalphosphorusremoval,theanaerobic–anoxicsequencingbatchreactor(A2SBR)processhasbeenrecentlyproposedbydifferentresearchers(Vlekkeetal.,1988;Wanneretal.,1992;Kubaetal.,1993;Bortoneetal.,1994;Sormetal.,1996).TheA2SBRisanattractiveprocessbecauseofthesavingoforganicmatterandenergyascribedtoaerationandlowsludgeproductionforcompletephosphorusandnitrogenremoval(Kubaetal.,1993,1994,1996).Dur-i