DenitrificationinanaerobicdigestersPossibilitiesan

Thisarticlewasdownloadedby:[TongjiUniversity]On:30January2015,At:00:47Publisher:Taylor&FrancisInformaLtdRegisteredinEnglandandWalesRegisteredNumber:1072954Registeredoffice:MortimerHouse,37-41MortimerStreet,LondonW1T3JH,UKEnvironmentalTechnologyPublicationdetails,includinginstructionsforauthorsandsubscriptioninformation::PossibilitiesandinfluenceofwastewaterCOD/N‐NOXratioJ.C.Akunnaa,C.Bizeaua&R.MolettaaaLaboratoiredeBiotechnologiedel'EnvironnementdesIndustriesAgro‐Alimentaires(LBEIAA),InstitutNationaldelaRechercheAgronomique,BoulevardGénéraldeGaulle,Narbonne,11100,FrancePublishedonline:17Dec2008.Tocitethisarticle:J.C.Akunna,C.Bizeau&R.Moletta(1992)Denitrificationinanaerobicdigesters:PossibilitiesandinfluenceofwastewaterCOD/N‐NOXratio,EnvironmentalTechnology,13:9,825-836,DOI:10.1080/09593339209385217Tolinktothisarticle:(the“Content”)containedinthepublicationsonourplatform.However,Taylor&Francis,ouragents,andourlicensorsmakenorepresentationsorwarrantieswhatsoeverastotheaccuracy,completeness,orsuitabilityforanypurposeoftheContent.Anyopinionsandviewsexpressedinthispublicationaretheopinionsandviewsoftheauthors,andarenottheviewsoforendorsedbyTaylor&Francis.TheaccuracyoftheContentshouldnotberelieduponandshouldbeindependentlyverifiedwithprimarysourcesofinformation.TaylorandFrancisshallnotbeliableforanylosses,actions,claims,proceedings,demands,costs,expenses,damages,andotherliabilitieswhatsoeverorhowsoevercausedarisingdirectlyorindirectlyinconnectionwith,inrelationtoorarisingoutoftheuseoftheContent.Thisarticlemaybeusedforresearch,teaching,andprivatestudypurposes.Anysubstantialorsystematicreproduction,redistribution,reselling,loan,sub-licensing,systematicsupply,ordistributioninanyformtoanyoneisexpresslyforbidden.Terms&Conditionsofaccessandusecanbefoundat©PublicationsDivision,SelperLtd.1992DEMTRIFICATIONINANAEROBICDIGESTERS:POSSIBILITIESANDINFLUENCEOFWASTEWATERCOD/N-NOxRATIOJ.C.AKUNNA,C.BIZEAU*ANDR..MOLETTAInstitutNationaldelaRechercheAgronomique,LaboratoiredeBiotechnologiedel'EnvironnementdesIndustriesAgro-Alimentaires(LBEIAA),BoulevardGénéraldeGaulle,11100Narbonne,France(Received10October1991;Accepted10April1992)ABSTRACTLaboratory-scalecompletely-stirredanaerobicdigesterswerefedwithsyntheticwastewaterscontainingnitrateandnitriteandwithglucoseastheonlysourceoforganiccarboninordertoinvestigateandcomparethedenitrificationpotentialsofanaerobicdigestersinthepresenceofnitrateandnitrite.VaryingtheinputnitrateandnitriteconcentrationatfixedCODandHRT,methaneproductionwithoutdenitrificationoccurredatCOD/N-NOx53;denitrificationandmethaneproductionat8.86COD/N-NOx53andonlydenitrificationatCOD/N-NOx8.86.AtCOD/N-NOx53,ammonificationappearedtobethemainnitrateandnitritereductionpathway.Thesuccessfulcompetitionofammoniaformersoverthetruedenitrifiersathighratioswasattributedtothelowinitialnitrateandnitriteconcentrations.Keywords:Anaerobicdigestion,denitrification,ammonification,methane,CODINTRODUCTIONAnaerobicdigestionofwastewaterstoproducemethaneandespeciallytobiodegradethewasteiswidelyemployedinthetreatmentofagriculturalwastewaters.Inmostcases,themethaneisnotalwaysrecoveredandutilised.Theby-productsofthismethodoftreatmentarethebiomass,methane,ammonia,carbondioxideandhydrogensulphide.Sinceammoniaistheresultofproteindigestion,highammoniaconcentrationsareoftenfoundinthetreatedeffluentsoffoodprocessingwastewaters.Beyond1500-3000mgN-NH3I'1ammoniahasbeenfoundtoinhibitmethanogenesisathighpHvalues(1,2).Themostwidelyusedmethodforammoniaremovalisthebiologicalmethodwhichconsistsofnitrificationanddenitrification.Innitrification,thenitrifyingbacteriaoftypesNitrosomonasandNitrobacterconverttheammoniatonitrateandnitriteunderaerobicconditions.Thebiologicalnitratereductioncanbeeitherassimilatoryordissimilatory.Assimilatorynitratereductioninvolvesthereductionofnitratetonitriteandthentoammoniaforcellsynthesis.Thisreductioniscontrolledbythequantityofammoniainthemedium(3)andiscommonincaseswherenitrateistheonlynitrogensource.Plants,fungi,algaeandsomefacultativebacteriaaresomeorganismscapableofcarryingoutthisprocess.Nitratereductionunderanaerobicconditionswherebysomebacteriautilisenitrateinsteadofoxygenasaterminalelectronacceptoristermeddissimilatory.Twotypesofreactionscharacterisethisprocess:Inthefirstreaction,nitrateisreducedtonitritewhichisfurtherreducedtogaseousproductssuchasnitrogenornitrousoxide,aprocesscallednitraterespirationordenitrification.Thesecondreactioninvolvesthereductionofnitratetoammoniavianitrite,aprocessknownasammonification.Denitrificationisapropertyoffacultativeorstrictanaerobicbacteria.Pseudomonas,Achromobacter,Bacillusaresomeofthebacteriawithhighdenitrifyingcapabilities(4).825Downloadedby[TongjiUniversity]at00:4730January2015HIGHMWPOLYM