NitrifyingMovingBedBiofilmReactorBiofilmandBiomass

AcceptedManuscriptNitrifyingMovingBedBiofilmReactor(MBBR)BiofilmandBiomassResponsetoLongTermExposureto1oCV.Hoang,R.Delatolla,T.Abujamel,W.Mottawea,A.Gadbois,E.Laflamme,A.StintziPII:S0043-1354(13)00929-9DOI:10.1016/j.watres.2013.11.018Reference:WR10328Toappearin:WaterResearchReceivedDate:1August2013RevisedDate:4November2013AcceptedDate:12November2013Pleasecitethisarticleas:Hoang,V.,Delatolla,R.,Abujamel,T.,Mottawea,W.,Gadbois,A.,Laflamme,E.,Stintzi,A.,NitrifyingMovingBedBiofilmReactor(MBBR)BiofilmandBiomassResponsetoLongTermExposureto1oC,WaterResearch(2013),doi:10.1016/j.watres.2013.11.018.ThisisaPDFfileofanuneditedmanuscriptthathasbeenacceptedforpublication.Asaservicetoourcustomersweareprovidingthisearlyversionofthemanuscript.Themanuscriptwillundergocopyediting,typesetting,andreviewoftheresultingproofbeforeitispublishedinitsfinalform.Pleasenotethatduringtheproductionprocesserrorsmaybediscoveredwhichcouldaffectthecontent,andalllegaldisclaimersthatapplytothejournalpertain.MANUSCRIPTACCEPTEDACCEPTEDMANUSCRIPTGraphicalAbstractAirMorphology&ThicknessofMBBRCarriersMixingPatternViabilityofBiomassatdepth,Live(green)&Dead(red)MixingPatternMANUSCRIPTACCEPTEDACCEPTEDMANUSCRIPT1Title:NitrifyingMovingBedBiofilmReactor(MBBR)BiofilmandBiomass1ResponsetoLongTermExposureto1oC2V.Hoanga,R.Delatolla*a,T.Abujamelb,W.Mottaweab,A.Gadboisc,E.Laflammec,A.3Stintzib4aDepartmentofCivilEngineering,UniversityofOttawa,Ottawa,Ontario,K1N6N55bOttawaInstituteofSystemsBiology,DepartmentofBiochemistry,Microbiology,and6Immunology,UniversityofOttawa,Ontario,K1H8M57cJohnMeunierInc.,Montreal,Quebec,H4S2B38*Correspondingauthor:DepartmentofCivilEngineering,UniversityofOttawa,Ottawa,9ON,161LouisPasteur,K1N6N5;E-mail:[e-mail],Phone:[phone]ext.267711MANUSCRIPTACCEPTEDACCEPTEDMANUSCRIPT212ABSTRACT13Thisstudyaimstoinvestigatemovingbedbiofilmreactor(MBBR)nitrificationrates,14nitrifyingbiofilmmorphology,biomassviabilityaswellasbacterialcommunityshifts15duringlong-termexposureto1oC.Long-termexposureto1oCisthekeyoperational16conditionforpotentialammoniaremovalupgradeunitstonumerousnorthernregion17treatmentsystems.TheaveragelaboratoryMBBRammoniaremovalrateafterlong-term18exposureto1oCwasmeasuredtobe18±5.1%ascomparedtotheaverageremovalrate19at20oC.Biofilmmorphologyandspecificallythethicknessalongwithbiomassviability20atvariousdepthsinthebiofilmwereinvestigatedusingvariablepressureelectron21scanningmicroscope(VPSEM)imagingandconfocallaserscanningmicroscope22(CLSM)imagingincombinationwithviabilitylive/deadstaining.Thebiofilmthickness23alongwiththenumberofviablecellsshowedsignificantincreasesafterlong-term24exposureto1oC.Hence,thisstudyobservednitrifyingbacteriawithhigheractivitiesat25warmtemperaturesandaslightlygreaterquantityofnitrifyingbacteriawithlower26activitiesatcoldtemperaturesinnitrifyingMBBRbiofilms.UsingDNAsequencing27analysis,NitrosomonasandNitrosospira(ammoniaoxidizers)aswellasNitrospira28(nitriteoxidizer)wereidentifiedandnopopulationshiftwasobservedbetween20oCand29afterlong-termexposureto1oC.30KeyWords:Nitrification;coldtemperature;MBBR;biofilmmorphology;biomass31viability;bacterialpopulationanalysis321.Introduction33MANUSCRIPTACCEPTEDACCEPTEDMANUSCRIPT3Ammoniadischargedfromwastewatereffluentisresponsibleforthetoxicityofnatural34wateraroundtheworldandparticularlyinnorthernregions(CanadaGazette,2012).The35processofnitrificationisthemosteconomicalmeansofammoniaremoval(Metcalfand36Eddy,2003),andassuchammoniaremovalincoldclimatesoftenbecomesextensively37limitedornon-existentduetothetemperaturesensitivityofnitrifiers(SharmaandAhlert,381977;PainterandLoveless,1983).Contrarytoconventionalsuspendedgrowth39processes,attachedgrowthprocessesandspecificallythemovingbedbiofilmreactor40(MBBR)haveshownanabilitytoachieveandmaintainlowertemperaturenitrification41(WessmanandJohnson,2006;Houwelingetal.2007;Delatollaetal.2011;DiTrapaniet42al.2013;Zhangetal.2013).Hence,MBBRsystemshavedemonstratedpromiseasa43potentialupgradeorreplacementtechnologyforlowtemperatureammoniaremoval.44Passivewastewatertreatmentsystemssuchaswetlandsandlagoonsarecommonin45northernregionsduetoavailabilityofland.Forexample,therearecurrentlyover100046lagoonsystemsoperatingaswastewatertreatmentfacilitiesinCanadaaloneanddueto47recentammoniaeffluentdischargeregulationsmanyoftheseexistingtreatmentlagoons48willrequireupgradinginthenearfuture(CanadaGazette,2012).Todate,MBBR49upgradeunitsthathavedemonstratedtheabilitytonitrifyatlowtemperatureshavebeen50investigatedandimplementedtotreattheeffluentfromthefirstormiddlelagoonofa51multiplelagoontreatmentsystems;wheretemperaturedropsarelimitedandthe52carbon/nitrogen(C/N)ratioishigherthanthedownstreamponds(Delatollaetal.2011).53HigherC/Nratios,specificallythepresenceofinfluentreadilydegradablecarbon,54increasesthequantityofheterotrophicgrowthinthesystem.Theheterotrophs55outcompetethenitrifiersforoxygenandmaysignificantlyaltertheactivityofthe56MANUSCRIPTACCEPTEDACCEPTEDMANUSCRIPT4nitrifyingcommunitiesandtheabilityofthesystemtoremoveamm