Engineeredbiofiltrationfortheremovalofdisinf

See discussions, stats, and author profiles for this publication at: Biofiltration for the Removal ofDisinfection By-Product Precursors andGenotoxicityArticle in Water Research · September 2015DOI: 10.1016/j.watres.2015.05.034CITATIONS3READS1494 authors, including:Liz Taylor-EdmondsUniversity of Toronto12 PUBLICATIONS 72 CITATIONS SEE PROFILESusan AndrewsUniversity of Toronto55 PUBLICATIONS 597 CITATIONS SEE PROFILERobert C. AndrewsUniversity of Toronto101 PUBLICATIONS 1,352 CITATIONS SEE PROFILEAll content following this page was uploaded by Liz Taylor-Edmonds on 25 September 2015.The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original documentand are linked to publications on ResearchGate, letting you access and read them immediately.Engineeredbiofiltrationfortheremovalofdisinfectionby-productprecursorsandgenotoxicityMichaelJ.McKie*,LizTaylor-Edmonds,SusanA.Andrews,RobertC.AndrewsDepartmentofCivilEngineering,UniversityofToronto,35St.GeorgeStreet,Toronto,OntarioM5S1A4,CanadaarticleinfoArticlehistory:Received21January2015Receivedinrevisedform18April2015Accepted18May2015Availableonline28May2015Keywords:EngineeredbiofiltrationDisinfectionby-products(DBPs)Naturalorganicmatter(NOM)HalogenatedfuranonesGenotoxicityDrinkingwaterabstractDisinfectionby-products(DBPs)areformedwhennaturallyoccurringorganicmatterreactswithchlo-rineusedindrinkingwatertreatment,andDBPsformedinchlorinateddrinkingwatersampleshavebeenshowntocauseagenotoxicresponse.TheobjectiveofthecurrentstudywastofurtherunderstandtheprinciplesofbiofiltrationandtheresultingimpactsontheformationofDBPsandgenotoxicity.Pilot-scalesystemswereutilizedtoassesstheperformanceofengineeredbiofiltersenhancedwithhydrogenperoxide,in-linecoagulants,andnutrientswhencomparedtopassivelyoperatedbiofiltersandcon-ventionaltreatment(coagulation,flocculation,sedimentation,non-biologicalfiltration).Organicfrac-tionationwascompletedusingliquidchromatography-organiccarbondetection(LC-OCD).Watersampleswerechlorinatedaftercollectionandexaminedfortheremovaloftrihalomethane(THM),haloaceticacid(HAA),andadsorbableorganichalide(AOX)precursors.Additionally,theformationpo-tentialoftwohalogenatedfuranones,3-chloro-4(dichloromethyl)-2(5H)-furanone(MX)andmucochloricacid(MCA),andgenotoxicitywasdetermined.BiofiltrationwasshowntopreferentiallyremovemoreDBPprecursorsthandissolvedorganiccarbon(DOC).Formationpotentialoftheunregu-latedDBPs,includingMXandMCA,andgenotoxicresponsewasshowntobecorrelatedtoTHMfor-mation.TheseresultsinferthatmonitoringforTHMsandHAAsprovideinsighttotheformationofmoremutagenicDBPssuchashalogenatedfuranones,andthatbiofiltrationmaypreferentiallyremovepre-cursorstoDBPsatarateexceedingtheremovalofDOC.©2015ElsevierLtd.Allrightsreserved.1.IntroductionNaturalorganicmatter(NOM)representsamixtureofchemicalsfoundinwatersystems.AlthoughNOMitselfisnotregardedasahealthhazard,whencombinedwithchlorineusedfordisinfectionduringdrinkingwatertreatmentawiderangeofdisinfectionby-products(DBPs)areformed.TheseDBPsincludecommonlyregu-latedgroupsofcompoundssuchastrihalomethanes(THMs),andhaloaceticacids(HAAs),aswellaslesscommonandunregulatedcompoundsofhealthconcernsuchasthehalogenatedfuranones:3-chloro-4(dichloromethyl)-2(5H)-furanone(MX)andmucochloricacid(MCA)(Krasneretal.,2006).TheUSEPAhassetregulatorylimitsforTHMs(80mg/L)andthefivemostcommonHAAs(HAA5)(60mg/L)whileHealthCanadahassetguidelinesfortheconcentrationofTHMsandHAA5at100mg/Land80mg/L,respectively(USEPA,2012;HealthCanada,2008;2009).Whenpresentindrinkingwaterthesecompoundsmaycreateagenotoxicorcarcinogenicresponse(Richardsonetal.,2007).Assuch,itisimportanttominimizeNOMtolimitDBPformation.Biologicallyactivefiltration(biofiltration)representsanimportantwatertreatmentoptionbecauseofitsabilitytoreducebiodegradableorganicmatter(LeChevallieretal.,1992),anddisinfectionby-productprecursors(Onstadetal.,2008),whileachievingaccept-ablefiltrationperformancewithrespecttoparticleremoval(Emelkoetal.,2006).However,untilrecentlybiofiltrationhasbeenoperatedinapassivemannerwithoutanthropogenicinfluences.Lauderdaleetal.(2012)introducedtheconceptofengineeredbiofiltrationwherebyphosphorusandnitrogenwereaddedtoin-creasebiofilmgrowthandactivitytoincreasereductionofDOC.ThisstudyreportedDOCremovalincreasesfrom0.4mg/Lto0.75mg/LwithaninfluentDOCofapproximately3.0mg/L.Hydrogenperoxidewasintroducedtolimitheadlossresultingfromextracellularpolymericsubstance(EPS)formationbyupto66%withoutimpactingDOCremoval.Azzehetal.(2015)furtheredthistypeofresearchbyexaminingtheremovalofbiopolymersaspo-tentialultrafiltrationmembranefoulantsandprecursorstoTHM,*Correspondingauthor.E-mailaddress:[e-mail](M.J.McKie).ContentslistsavailableatScienceDirectWaterResearchjournalhomepage:://dx.doi.org/10.1016/j.watres.2015.05.0340043-1354/©2015ElsevierLtd.Allrightsreserved.WaterResearch81(2015)196e207HAAandAOXformation.However,pr