Effects of ammonium ions from the anolyte within bio-cathode mfc on nitrate reduction and current

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Effectsofammoniumionsfromtheanolytewithinbio-cathode

microbialfuelcellsonnitratereductionandcurrentdensity

JiyeonKima,*,ByunggoonKima,HongsuckKima,ZuwhanYunb

aWaterResearchCenter,K-waterInstitute,125,1689thGil,Yuseong-daero,Daejeon305-730,RepublicofKoreabPrograminEnvironmentalTechnologyandPolicy,KoreaUniversity,Anam-dong,Seongbuk-ku,Seoul136-701,RepublicofKorea

articleinfo

Articlehistory:Received14January2014Receivedinrevisedform21April2014Accepted21April2014Availableonline16May2014

Keywords:AmmoniumtransfereffectMicrobialfuelcellsNitrateremovalTwo-chamberbio-cathodemicrobialfuelcellWastewatertreatmentabstract

Thisstudywastodeterminetheeffectsoftheammoniumionintheanolyteofthetwo-chamberbio-cathodeMFC,whichusesnitrateionsasthefinalelectronacceptor,onthenitratereductionandthecurrentdensity.Theammoniumnitrogenmasstransfercoefficientwas3Â10À6cm/sandthediffusivitywas6Â10À8cm2/sthroughNafion117underabioticconditions,withthecircuitdisconnected.WhentheTCBC-MFCwasoperatedat96.6Æ11.2mg/LofSCODcrintheanodechamberand37.9Æ2.8mg/Lofnitratenitrogeninthecathodechamberatanexternalresistance100U,theanalyticaldenitrificationratewasbeing7.89Æ0.78g/m3dinthepresenceofammoniumionsand3.07Æ0.26g/m3dintheabsenceofammoniumions.Thecurrentdensitywas176.1Æ31.7mA/m2whenNH4þ-Nwaspresentintheanolyteand28.2Æ19.4mA/m2withoutNH4þ-N.Thus,itwasdeterminedthattheammoniumionsintheanolytewerepromotedelectronmovement,whichincreasedthedenitrificationratetotwicethatintheammonium-freesystem.Ó2014ElsevierLtd.Allrightsreserved.

1.Introduction

Nitrogenremovalmethodsaretypicallyclassifiedaseither

abioticorbiological.Someabioticmethodsthatarecommonlyused

toremovenitratesfromwaterarereverseosmosis,ion-exchange,

electroadsorption,andnanofiltration(SchoemanandSteyn,2003;

HanandChang,2013).However,thesemethodssufferfrom

variousdrawbackssuchastheproductionofbrineorotherby-

products(Ghafarietal.,2008).Biologicalmethodscanbe

employedtoreducenitratestonitrogengasbyusingheterotrophic

andautotrophicdenitrifiers.Heterotrophicdenitrificationisa

removalmethodthatcombinesbiologicalnitrificationanddeni-

trification,withorganiccarbonasanelectrondonor,whileauto-

trophicdenitrificationutilizeshydrogenandsulfuraselectron

donors(Changetal.,1999;Zhaoetal.,2011).Moreover,autotrophic

denitrificationusingbio-electrochemicalsystemshasrecentlybeen

studied(Parketal.,2005;Jeremiasseetal.,2010).

Microbialfuelcells(MFCs)haverecentlybeenemployedasa

noveltechnologyforwastewatertreatmentsincetheyarecapable

ofremovingorganicmatterandgeneratingelectricalpower(Loganetal.,2006).Furthermore,manyresearchershavedevelopedMFCs

fornitrogenremovalandrecovery(Gregoryetal.,2004;Ohand

Logan,2005;Heijneetal.,2010;Fangetal.,2011).

Clauwaertetal.(2007)initiallyexaminedthesimultaneous

removalofanorganicsubstrate,powerproduction,anddenitrifi-

cationbyusinganMFCwithoutrelyingontheformationofH2oran

externalpowersource,undertheassumptionoftheconversionof

NH4þ-NintoNO3À-N.Modifiedprocessesforthetotalremovalof

organicsubstratesandnitrogeninwastewaterbasedonbio-

cathodeMFCshavebeenpreviouslyreported.Virdisetal.(2008)

demonstratedtheoperationofabio-cathodeMFCusingasepa-

ratenitrificationtank,whileZhangandHe(2012)attemptedto

integratethenitrificationanddenitrificationprocesseswithina

singleMFCbyusingtwoaerobicandanoxiccathodes.

DuringwastewatertreatmentwithMFCs,NH4þ-Nwithinthe

wastewaterdiffusesthroughthemembraneandreachesthecath-

odechamber(Logan,1999),subsequentlymaintainingthecharge

balance(Rozendaletal.,2006).Whenthewastewaterwastreated

withthetwo-chamberMFC,theammoniumionsweredetectedin

higherconcentrationswithinthecathodeeffluentasaresultofthe

movementoftheseions(Virdisetal.,2008).Previousstudies

involvingthelossofammoniumionsinsingle-andtwo-chamber

MFCsreportedthattheammoniumtransportrateincreasedas

thegenerationofelectricityincreased,andthattheNH4þ-Nwasnot

necessaryfortheproductionofelectricity(Kimetal.,2008

).*Correspondingauthor.E-mailaddresses:jy.kim@kwater.or.kr(J.Kim),bgkim@kwater.or.kr(B.Kim),waterkim@kwater.or.kr(H.Kim),envzyun@korea.ac.kr(Z.

Yun).ContentslistsavailableatScienceDirect

InternationalBiodeterioration&Biodegradation

journalhomepage:www.elsevier.com/locat

e/ibiod

http://dx.doi.org/10.1016/j.ibiod.2014.04.0150964-8305/Ó2014ElsevierLtd.Allrights

reserved.InternationalBiodeterioration&Biodegradation95(2014)122e126Theaimofthisinvestigationwastodeterminetheeffectsof

theammoniumionintheanolyteofthetwo-chamberbio-

cathodeMFC(TCBC-MFC),whichusesnitrateionsasthefinal

electronacceptor,onthenitratereductionandthecurrent

density.

2.Materialsandmethods

2.1.TCBC-MFCsetupandoperation

Inthisstudy,atwo-chamberbio-cathodeMFC(TCBC-MFC)was

constructedusingabench-scalereactortoremovetheorganic

matterandnitrateionsinthewastewater.Theorganicmatterwas