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