multi-component solute transport model with cation ...64-1-6).pdf · uses fe（oh）3as electron...

九州大学学術情報リポジトリKyushu University Institutional Repository

Multi-component Solute Transport Model withCation Exchange under Redox Environment and itsApplication for Designing the Slow InfiltrationSetup

Guerra, GinggingInstitute of Environmental Systems : Graduate Student

Jinno, KenjiInstitute of Environmental Systems : Professor

Hiroshiro, YoshinariInstitute of Environmental Systems : Associate Professor

Nakamura, KojiInstitute of Environmental Systems : Graduate Student

http://hdl.handle.net/2324/3321

出版情報：九州大学工学紀要. 64 (1), pp.79-100, 2004-03. 九州大学大学院工学研究院バージョン：権利関係：

MemoirsoftheFacultyofEngineering，Kyushu University，Vol．64，No．1，March2004

Multi－COmPOnentSoluteTransportModelwithCationExchangeunderRedox

EnvironmentanditsApplicationforDesigning・theSlowInfiltrationSetup

by

GinggingGuERRA＊，KenjiJINNO＊＊，YoshinariHIROSHIRO＊＊＊andKojiNAKAMURA＊

（ReceivedDecember17，2003）

Abstract

Thepresenttrendofdisposingtreatedsewagewaterbyallowingitto

infiltratethesoilbringsanewdimensiontoenvironmentalproblems．It

is therefore necessary toidentify the chemicalslikely to be presentin

treated sewage water．A soilcolumn experiment was conducted to

determinethebehaviorofchemicalspeciesinsoilcolumnsappliedwith

SeCOndarytreatedsewagewater．To predict the behavior ofchemical

SpeCies，amulticomponentsolutetransportmodelthatincludesthebio－

Chemicalredoxprocessandcationexchangeprocesswasdeveloped．The

modelcomputeschangesinconcentrationovertimecausedbytheproces－

SeSOfadvection，dispersion，biochemicalreactions andcationexchange

reactions．Thesolutetransportmodelwasabletopredictthebehaviorof

different chemicalspeciesin the soilcolumn applied with secondary

treated sewage water．The modelreproduced the sequentialreduction

reaction．To designthesafe depth ofplowlayerwhere NOtis totally

reduced，anumericalstudyofNOi．1eachwasdoneanditwasfoundout

thattheporevelocityandconcentrationofCH20attheinjectwaterwas

found to affect NO訂reductionin the mobile pore water phase．Itis

revealed that the multicomponent solute transport modelis usefulto

designthelandtreatmentsystemforNO3remOValfromwastewater．

Keywords：Biochemicalredoxprocesses，Cationexchangeprocesses， Microbiallymediatedredoxreactions

Nomenclature

［Ci］m。b：Concentrationofchemicalspeciesiinthemobileporewaterphase（mmol／L）

［Ci］bi。：Concentrationofchemicalspeciesiinthebiophase（mmol／L）

［Ci］m。t：Concentrationofchemicalspeciesiinthematrixphase（mmol／L）

［Ci］im：Concentrationofchemicalspeciesiinthesolidphase（mmol／L）

γ’：Porewatervelocity（cm／sec）

t：Time（sec）

＊GraduateStudent，InstituteofEnvironmentalSystems

＊＊Professor，InstituteofEnvironmentalSystems

＊＊＊AssociateProfessor，InstituteofEnvironmentalSystems

80 G．GuERRA，K．JINNO，Y．HIROSHIROandK．NAKAMURA

z：Distance（cm）

D：Hydrodynamicdispersioncoefficient（cm2／sec） Sl（i）：Exchangereactiontermattheconcentrationdifferencebetweentheporewaterandthe biophase

S2（i）：Exchangereactiontermattheconcentrationdifferencebetweenporewaterandthe soil matrix

S3（i）：Cationexchangereactiontermbetweentheporewaterandthesolidphase N：Correspondto9chemicalspeciesNa＋，K＋，Mg2＋，Ca2＋，Mn2＋，Fe2＋，02，NO訂andCH20

α：Exchangecoefficient（1dayMl）

β：Exchangecoefficient（1day‾1）

γ：Exchangecoefficient（1dayul）

Obi。：Watercontentforbiophase

8u，：Watercontentformobilephase

Om。t：Watercontentformatrixphase

S3Fe2十：PorewaterandsolidphaseexchangereactiontermofFe2＋ KcH20：HalfvelocityconcentrationforCH20（mmol／L） jら2：HalfvelocityconcentrationforO2（mmol／L）瓜03－：HalfvelocityconcentrationforNO言（mmol／L） V£ax：MaximumgrowthrateofaerobicBacteriaXl（1dayul） u農芸‾：MaximumgrowthrateofanaerobicBacteriaXl（1day‾1）班慧2：MaximumgrowthrateofBacteriaX2（1day－1） u£昌㌘H）3：MaximumgrowthrateofBacteriaX3（1day‾1）

uxldec：ConstantdecayrateofBacteriaXl（1day¶1） ux2de。：ConstantdecayrateofBacteriaX2（1day‾l）

ux3dec：ConstantdecayrateofBacteriaX3（1day¶1） ICNO3－：InhibitionconcentrationofNO訂againstO2（mmol／L）

j㌔e2＋：Productionfactorfor Fe2＋

P肋2．：Productionfactor for Mn2＋

Ub之：GrowthyieldfactorforO2 LLvo3－：GrowthyieldfactorforNO訂 Lhe（OH）3：GrowthyieldfactorforFe（OH）3

tL4nO2：Growthyieldfactorfor MnO2

‡諾2。：YieldingcoefficientofO2 ‡甥払：YieldingcoefficientofNO訂

‡′詔H）3：YieldingcoefficientofFe（OH）3

i筍皆：YieldingcoefficientofMnO2 ん：Slopeofswitchfunction O2th，eS：ThresholdvalueofO2（mmol／L）

F（02bi。）：SwitchingfunctionofO2

1．Introduction

Wastewatertreatmentbyland applicationhasbeeninpracticeinmanyparts ofthe

WOrldbecauseitisbelievedthatpassagethroughthesoilenvironmentofwastewaterwill

provide further removalofcertain chemicaland microbialcontaminants．The structure，

ChemistryandthebiologlCalactivityinsomesoilsmakethemidealtotreatwastewaterto

PrOteCtgrOundandsurfacewater．Wastewaterdisposalonlandwillbeaviabletreatment

methodonlyiftheprotectionofgroundwaterfrompossibledegradationisheldasaprlmary

81 SoluteTransportModelwithCationExchangeunderRedoxEnvironment

objective（Polprasert，1996）．The present trend of disposing treated sewage water by

allowlngittoinfiltratethesoilbringsanewdimensiontoenvironmentalproblems・Nitrogen fromsuchtreatmentsystemsiscurrentlyofconcernbecauseofthenitratecontaminationof

drinkingwatersuppliesandtheeutrophicationofcoastalwaters．Thereforeitisnecessary

to study the governing mechanisms for the transport and fate of nitrogen and other

contaminantsfromtreatedsewagewater．Thedevelopmentanduseofmathematicalmodels

provides a better understanding of theimportant biological，Chemicaland hydrological

processes relevant to contaminant transport・In order to predict the effect of nitrate

pollutiononthelongtermwaterresourcequality，mOdelshavetobeconstructedwhichboth

yieldaquantitativeexplanationofthepresentstateandpredictfuturedevelopments・Such modelsshouldbebasedonaproperunderstandingbothofnitratetransportthroughaquifers

andofchemicalprocesseswithinaquifersthatmayaffectnitrateconcentrations．Attempts

tomodelnitratetransportandreductioninaquifershavesofarbeenfew（Frindetal，1990；

KinzelbachandSchAfer，1989）．

Duringthelastdecadecoupledmodelingofgroundwatertransportandchemicalreaction

hasgonethroughastrongdevelopment．Modelsrangefromsimpleone－dimensionaltrans－

portmodelscoupledwithequilibriumcodes（DanceandReardon，1983；AppelloandWillem－

sen，1987）to complex two or three－dimensionalmodels（Liu and Nasarimhan，1989a，b；

KinzelbachandSchafer，1989）．Mostworkhasbeendoneonionexchangeprocesses and

thesemodelsaretypicallyvalidatedbylaboratoryandfieldtracerexperiments（Vallochiet al，1981；Appelloetal．，1990）．Fewmodelsconsiderredoxreactions（LiuandNasarimhan， 1989a，b）sincetheypresentanincreasingnumericalcomplexity．Kineticreactive－tranSpOrt

models that have some redox capability usually in the form of biodegradation kinetics

includethosedevelopedbyMcNabandNasarimhan（1994）；Lensingetal．（1994）；Schafer andTherrien（1995）．

Forsimulatingnitrogen（N）transportandtransformations，nitrificationanddenitrifica－

tioningroundwatermustberepresentedbykineticexpressions，Whichtaketheform of multiple nutrient Monod type equations．Severalgroups of researchers have recently

simulatedheterotrophicdenitrificationinone－OrtWO－dimensionalsaturatedgroundwater flowsystems．Kinzelbachet al．（1991）was ableto describe theinteractivetransport of

oxygen，nitrate，Organic substrates and microbialmassin two dimensions，including the

possibility of diffusion－1imited exchange between different phasesin the aquifer・Three

modelphases（mobileporewater，biophaseandaquifermaterial）aretakenintoaccount・

Lensingetal．（1994）usedamulti－COmPOnenttranSpOrtreaCtionmodeltobacteriallycatal－

yzedredoxprocesses．Theexchangebetweenthethreedifferentphases：pOreWaterphase，

bio phase and aquifer matrixis also considered・The sub－mOdels are coupled with the

equationsofthemicrobiallymediatedredoxreactions．Schaferetal．（1998）developedthe

transport，biochemistryandchemistry（TBC）modelthatnumerica11ysolvestheequations

forreactivetransportinthree－dimensionalsaturatedgroundwaterflow．Solutetransportis

coupledwithmicrobiallymediatedorganiccarbondegradation．Microbialgrowthisassumed

tofollowMonodtypekinetics．Schaferetal．（1998）inhismodelapplicationtoacolumn

studyonorganiccarbondegradationconsideredfivemicrobialgroupsinthemodel・The modelprovidesatemporallyandspatiallyresoIvedquantificationofmicrobialdegradation

activity．

MacQuarieetal．（2001）havepresentedthetheoryandnumericalsolutionofareactive

transportmodelthatisintendedtorepresentthemajorflow，tranSpOrtandbiogeochemical

processesinvolvedinwastewatermigrationinashallowaquifer・Anumericalmodelwas developedforvariablysaturatedflowandreactivetransportofmultiplespecies・Themodel


suggested that adding labile organic carbon sources to septic drain fields could enhance

heterotrophicdenitrificationandthusreduceNO訂COnCentrationinshallowgroundwater．

Thesimulationscouldhelptoclarifytheeffectofthewaysoforganicmatterapplicationon

theprocessofdenitrification．

Landapplicationoftreatedsewagewaterinthepaddyfieldhasgraduallybecomethe

mostpopularwayofreuse．Inapaddyfieldsituation，SuCCeSSivechemicaltransformations

OCCurlikedenitrification，0Ⅹidationandreduction（redox）reactions andcationexchange

reactions・0Ⅹidationandreductionprocessesexertanimportantcontrolonthedistribution OfchemicalspecieslikeO2，NO訂，Mn2＋andFe2＋etc．undernaturalconditioningroundwater．

StummandMorgan（1981）pointedoutthatthemostredoxprocessesencounteredinnatural aquaticsystemsneedbiologicalmediation．Sinceredoxprocessesarealwayscatalyzedby

SeVeralmicroorganisms，thechemicalreactionsareparalleledbyanecologicalsequenceof

microorganisms・Theextentandvelocityoftheseredoxreactions arestrictlycorrelated Withgrowthandmetabolismofseveralmicroorganisms．Thetreatmentofredoxreactions

asbiologicalprocesses deliversthe required data for kinetic approaches to modelredox

reactionsingroundwatersystems（StummandMorgan，1981）．

Theslowrateprocessoftreatmentofwastewaterisfocusedinthisstudy．Slowrate

processisthecontrolledapplicationofwastewatertolandat arate offewcentimetersof

liquidperweek・Theflowpathdependsoninfiltration，andusuallyonlateralflowwithinthe

treatmentsite・Treatmentoccursbymeansofphysical，ChemicalandbiologlCalprocessesat

thesurfaceandasthewastewaterflowthroughtheplant－SOilmatrix（Polprasert，1996）．

Nitrateisveryprominentamongthecontaminantsenteringthegroundwatersystems

fromfertilizationandwastewaterirrigation．Itishigh1ysoluble，mObileandrepresentsa

healthhazardtohumaninfantsatrelativelylowconcentrations（Burden，R．J．，1982）．The

recent recognition of denitrification as an active process for the removal of nitrate from

Certainfavorablehydrogeologicenvironmentsisanimportantstepintheunderstandingof

nitrateprocesses．Denitrificationisthebiologicallymediatedtransformationofnitrateto

nitrogengas．Thebacteriaresponsiblefordenitrificationarefacultativeanaerobesthatuse

nitrateinplaceofoxygenfortheirrespiratoryprocessesunderanaerobicconditions．This transformationrequires anorganiccarbonfoodsourceforthebacteria tometabolize and

CO2isformedasaproductofmetabolism（TrudellM．R．etal，1986）．

Thepurpose ofthisstudyisto assess andpredictthebehavior ofdifferent chemical

SpeCiesinsoilcolumnsappliedwithsecondarytreatedsewagewater・Asolutetransport modelthattakesintoconsiderationthebiochemicalreactionsandcationexchangereactions

WaSdeveloped・Theresultsofthesoilcolumnexperimentswerecomparedwiththeresults Ofsimulationmodel・Itwasfoundoutthatthemulticomponentsolutetransportmodelwas abletopredictthebehavior ofdifferentchemicalspeciesinthesoilcolumn appliedwith

SeCOndarytreatedsewagewater，howeveritisnecessarytodeterminethesafedepthofthe

plowlayerthatissafefornitrate（NO訂）1eaching．

Inthisstudy，thenumericalmodelingofNO言1eachwasdoneusingthemulticomponent

SOlutetransportmodeltodeterminetheeffectoftheporevelocityandinputCH20concentra－

tionneededtoreducetheNO訂COnCentration・Todesignthedepthoftheplowlayerthatis SafeforNOileaching，itisnecessaryto determinethe depthwhereNO訂Willbetotally

reduced・InthesimulationmodeltheinputvaluesofporevelocityandinputCH20concentrar tionwasvariedtodesignthesafedepthofplowlayerinsoilcolumns．


2．Methodology－SoilColumnExperiment

Thesoilcolumnexperimentwasconductedusingsoilscollectedfromactualpaddyfield

andwerepackedintwolOcmdiameterPVCcylindercolumnsofdifferentthicknessofplow

layerslOcmand20cmrespectively（Fig．1）．Treatedsewagewaterwasconstantlysupplied

upto5cmatthetopofthetwosoilcolumnsinordertoreproducetheredoxconditionsimilar

topaddyfield．Tablelshowstheconcentrationoftheinjectionwater．Glassbeadswereused

tosupporttheplowlayerinsoilcolumnat15cminbothsoilcolumns．Theexperimentwas

COnductedforthedurationof49daysandtheaveragetemperaturewasmeasuredat300C．

Tahle2showsthesoilpropertiesandTable3showsthechemicalcomponentsofthepaddy

SOil．Soilsolutionsamplesco11ectedbyporouscupsandcolumnoutflowwereanalyzedfor

Fig．1Experimentalcolumnequipment．

TablelConcentrationofinjectionwater．

Na＋ 10・146meq几 NH4＋ 0．432meq几

K＋ 0・775meq几 NO3‾ 0．378meq几

CaZ＋ 4・164meq几 TOC（CH20）6・23meq／L

MgZ＋ 2・085meq几 EC l．55mS／Cm

FeZ＋ 0・066meq几 pH 7・2

MnZ＋ 0・024meq几 Temperature 300c

Table2 Soilpropertiesofpaddysoil．

Cation exchange capacity Selectivitycoefficients

CEC（mmoIc／100g） Ⅹca仰a Kca／K Kca／Mg K色作e

13．52 0．453 0．0428 1．2 1．2

84 G．GuERRA，KJINNO，Y．HIROSIiIRO and K．NAKAMURA

Table3 Chemicalcomponentofpaddysoil．

Chemicalspecies ％composition

Fe203 5．34

MnO2 0．05

A1203 8．09

SiO2 77．58

CH20 6．08

C 1．96

H 0．7（i

N 0．15

Total 100．01

Na＋，K＋，Mg2＋，Ca2＋，Mn2＋，Fe2十，NHI－N and NO言－N concentrations．EC（Electrical

Conductivity），PHandORP（0ⅩidationReductionPotential）werealsomeasured．

3．The Multi－COmPOnent SoluteTransport M：odelConceptualModel

The biochemicaland chemicalmodel（Fig．2）describes theinteraction of O2，NO3J，

CH20，bacteria，MnO2，Fe（OH）3，Na十，K＋，Mg2＋，Ca2十，Mn2＋andFe2＋．Thismodeltakesinto

accountthemicrobiallymediatedredoxreactionandthecationexchangereaction．It also

takesintoconsiderationthefourdifferentmodelphases：mObileporewaterphase，immobile

biophase，SOlid matrix phase and solid phase．The bacteria are assumed to residein the

immobilebiophase．Exchangeprocessesareconsideredbetweenthedifferentmodelphases．

Theexchangebetweentwophasesismodeledbyalinearexchangeterm．Massexchangeof

dissolvedspeciesisgovernedbytheconcentrationdifferenceofthespeciesintheporewater

phase［Ci］m。b，thebiophase［Ci］bi。，thematrixphase［Ci］m。t andtheexchangecoefficients

⊂コ PoreWate一

Biophase

SolidPhase

02，NO3

Fig．2 Scheme ofbiochemicalmodel．

8,5 SoluteTransportModelwithCationExchangeunderRedoxEnvironment

αandβ．Thismodelbelongstothebiofilmmodels，Wheremicroorganismsareassumedto

resideintheimmobilebiophase．Thebiofilmmodelassumesmicrobesdistributethemselves

uniformlyoverthesoilparticlescreatingafilm．Internaldiffusionlimitsthetransportof

substrate and contaminants to the microbesin the film．In most biofilm models，a direct

exchangebetweenthebiophaseandtheaquifermaterialisnotconsidered（Schaferetal．，

1998）．

4．TheoreticalModelDevelopment－ReactiveSoluteTransportModel

The one－dimensionalpartialdifferentialequation governlng the convective－dispersive SOlutetransportofchemicalspeciesiconsideringbiochemicalandchemicalreactionsina

sub－aqueOuSSOilcanbewrittenas：（Bear，1972；Lensing，etal．，1994；Hiroshiroetal．，1999）

璧）＋β諷f）＋β∽S2（オ）十βぴS3（£）意（β鵡］椚0わ）＋意（β調Cよ］椚0わ）＝意（βぴβ （1）

whereiisthechemicalspeciesgivenbyi＝1，2，3，4，5，6，7，8，and9correspondtoNa＋，K十，

Mg2＋，Ca2＋，Mn2＋，Fe2＋，02，NO言andCH20，reSPeCtively．Ciistheconcentrationofchemical

speciesiintheporewater（mmoll‾1），γ，isporewatervelocity（cmsec‾1），tistime（sec），

xisdistance，Disthehydrodynamicdispersioncoefficient（cm2sec．1）．Sl（i），S2（i）andS3（i）

are the chemicalsink／source term representing the exchange with other phases and the

chemicalandbiochemicalreactions（mmoll‾1sec－1）andformulatedasfollows：

α払子。β∽ （［Cf］ゎ∠。一［Cf］m。む） β∽Sl（f）＝

β∽52川＝

鉄血＋βぴ

β／／い．．・・／ノ‥、（［Cz］m。f－［Cォ］∽。わ）

∂mαf＋β∽

βぴS3（f，＝諸（鋸C］ゎ花）

whereSl（i）istheexchangerateattheconcentrationdifferencebetweentheporewaterand thebiophase，S2（i）istheexchangerateattheconcentrationdifferencebetweenporewater

andthesoilmatrix，andS3（i）isthecationexchangereactionratebetweentheporewaterand

thesolidphase．［Ci］m。b，［Ci］bi。，［Ci］，n。tand［Ci］imCOrreSpOndtotheconcentrationofchemical

species（mmoll‾1）inthe pore water，the biophase，the soilmatrix，andthe solid phase，

respectively．αandβaretheexchangecoefficients．Inequations（2）and（3）thetheoryof

masstransportattheboundaryoffilminterfaceisapplied．Thebiophaseisconceptualized

as an operative means to easilyinclude diffusionlimited exchange process between the

mobileporewaterandbacteria．Thediffusionlimitationcanbedueeithertomicroscale（or

realbiofilm）diffusion or tolimited macroscale exchange between different zones of the

aquifer．Thisdiffusionaltransfercanberepresentedbymasstransportexchangecoefficients

αandβ（Kinzelbach et al，1991）．The chemicalspecies consideredin the modelare

summarizedinTable4．Eachchemicalspeciesrequiresanequationintheformofequilib－

rium equations．The formulation of equilibrium equations resultsin a high1y non－1inear

Table4 Chemicalspeciesconsideredinthemodel．

Porewater Na＋mobK＋mob MgZ＋mob Caヱ＋rrpb Mnヱ＋mob FeZ＋rnob O2mob NO3▼mob CH20mob

BioPhase 02bi。 NO3‾bi。MnZ＋bi。FeZ＋bi。 CH20。j。MnO2bi。Fe（OH）3bi。

SolidPhase Na＋im K＋jm MgZ＋im CaZ＋im Mn∠＋im FeZ＋im

Soilmatrix CH20mat MnO2mat Fe（OH）3mat

Bacteria Ⅹ1 Ⅹ2 Ⅹ3


partialdifferentialequations．

ForthechemicalspeciesrelatedtoFe2十thefo1lowingequationsareformulated： Biophase：

Ⅳ十‥眈0［Fe2＋］ゎfo）＝［］

払わ

j㌔e2＋

∂方3

∂才

α鈍才。β∽ （［ダe2＋］玩化√－［飽2十］m。わ）（5）

加乃鈍才。＋β∽

Fe（甜）3：如才0［F碑）3］占わト鞘［晋］卯び一激［Fe（α粘k一［瑚㈲ムαf）

（6）

払わ

抜e（0

Porewaterphase：

Fe2十：如肌ロb）十憲吋［軌ゐ）＝帥β

SolidPhase：

Ⅳ＋‥（βぴ［Ⅳ・］加）＝－βぴS3紗

SoilMatrix：

∂［飽2＋］m。占）＋豊（［軌－［Fe2＋］醐）＋βぴ53Fe2＋

（7）

（8）

Fe（0恥：意（‰［旅（甜）3］mαf）＝

Bacteria：

；′Jノ．‥り・い．・（［Fe（0耳）3］抽－［穐（0打）3］m。≠）（9）

鈍才。＋β∽。f

＝［晋］gγ。ぴ＋［ ∂方3 ㌢］

（10）

・方3 （11）

（12）

7、oJ（Jト▲（汀r）〟、〃i dec（Zツ

JC腑言［Cβ≧0］むZ。［飽（0打）3］ゎど。＝γ莞㌘）3・〝maX

groぴノC哺十［〃0㌻］ゐわ▼jら即＋［C筏0］白Z。▼‰（。柚十［飽（0〃）3］抽

＝－γズ3de。・方3

Wherea，γaretheexchangecoefficients，Obi。，Ow，and Om。tCOrreSpOndtowatercontentfor

biophase，mObilephaseandmatrixphaserespectively，j㌔e2＋istheproductionfactorforFe2＋，

the（OH）3isthegrowthyield factor for Fe（OH）3，S3Fe2十is the pore water andsolid phase

exchangereactiontermofFe2＋，ICNO5istheinhibitionconcentrationofNO言againstO2，KcH20

isthehalfvelocityconcentrationforCH20，7）孟冨㌘H）3isthemaximumgrowthrateofbacteria

X3andvx3decistheconstantdecayrateofbacteriaX3．

5，Bacteria Growth

The modeling of complex redox sequences requires the consideration of different

metabolisms・Italsorequirestheconsiderationofavarietyofsubstrates，includingorganic

COmpOunds，02，NO訂，MnO2andFe（OH）3．Sinceeachmodeofenergymetabolismisassociaト

edwithadifferentfunctionalbacterialgroup，thegrowthofeachgroupmustbeconsidered

inthemodel（KindredandCelia，1989）．Inthismodelthethreefunctionalbacterialgroups，

bacteriaXl，Ⅹ2andX3thatareassumedtoresideintheimmobilebiophaseareconsidered．

Table5showsthesequentialredox chemicalreactionofbacteria Xl，Ⅹ2andX3．Inthe

model，thebacteriagroup Xlusesunder aerobic conditions，mOlecularoxygen andunder

denitrifyingconditions，NO訂aselectronacceptor．BacteriaX2usesMnO2WhilebacteriaX3

uses Fe（OH）3aS electron acceptor．The microorganisms use dissoIved organic carbon

Chemically defined as CH20andthe utilizable portion of dead bacteria of90％as their

Substrate．BacteriaXl，Ⅹ2andX30XidizesCH20toCO2inthemodel．


Table5 Chemicalreactions ofbacteria．

Bacteria Reaction

AerobicXl CH20＋02⇒CO2＋H20

DenitritylngXl CH20＋4／5NO3‾＋4／5H十⇒CO2＋2／5N2＋7／5H20

ManganeSereducingX2 CH20＋2MnO2＋4H＋⇒2Mn2＋＋3H20＋CO2

IronTeduciI鳩Ⅹ3 CH20十4Fe（OHか8打⇒4Fe2＋＋11H20＋CO2

Attachedbacteriahaveanadvantageoversuspendedbacteriaanddominatetheheter－

OtrOphicdegradationofdissolvedorganiccarbon（BouwerandCobb，1987）．Theiruptakeof

Substrateandelectronacceptorstakesplace onlyvia theimmobile water phase．Though

existinginrealaquifers，mObilebacteria arenotconsideredinthemodel．

Inaerobicpartsofaquifersthemicrobialpopulationisusuallydominatedbyheterotro－

phicbacteria．Thisbacteriausesdissolvedorganiccarbonasenergyandcarbonsourceand

molecular oxygen as electron acceptor．Further heterotrophic metabolisms uslng Other

electron acceptors are suppressedbythepresence of oxygen．Some aerobic bacteria are

Capableofnitrate－reducingmetabolism．Thenecessaryenzymesarenotmaintainedandare

inducedbylowoxygenconcentrations（BouwerandCobb，1987）．Thegrowthandmetabo－

1ismofdifferentgroupsofmicrobialpopulationsintheimmobilebiophaseisbasedonMonod

kinetics and are formulated as follows：

］

＝愕1］軋。r。ぴtわ αeγ。れ。。肋＋［祭］。e柵醐。宣如乃＋［晋］励

（13）

・芽1 （14）

［C筏0］ゎ∠。［02］抽＝γ£まⅩ・（1－F（02らオ。））・

jら翫。十［C筏0］ゎゎTjら2＋［02］ゎど。

［C践0］玩わ［Ⅳ0㌻］占わ

αer（フむfc＿C（フ乃d才f∠0乃

＝γ霊宝・（ダ（02わわ））・・方1 （15）

（16）

（17）

（18）

（19）

・方3 （20）

（21）

（22）

jら〃2。＋［C筏0］摘▼花Ⅴ。喜＋［銅片］玩わ de乃才子rめオ乃g－C（フ乃dオ≠わ乃

＝－γズ1de。・方1

ノCⅣ。言［C践0］如厄［肋02］占わ＝γ濫誓2・・」Y2 ‾〝max

卯び JC胴）汗［入り訂］占わ‾‰2。十［C筏0］白Z。‾‰。2十［肋02］ゎォ。

＝－γズ2de。・芽2

九＝［晋］gγ。ぴ＋［掌］幽 Tofα～Cγ0乙びf

JC〃。言［C筏0］ゎf。［Fe（0仔）3］占Z。＝γ孟昆㌘勒・ ‾〝max

gr。∽ JC鳩十［州芳］抽‾‰2。＋［C践0］占わ▼‰（α仇＋［Fe（0〃）3］bg。

～γズ3dg。・ガ3 ］ ∂≠ decαγ

F（02白∠。）＝0．トもa。－1［02玩わー02柚）ん］方

whereXl，Ⅹ2andX3correspondtotheconcentrationofO2andNO訂，MnO2andFe（OH）3

reducingbacteria，7）£まx，V霊宝，γ濫誓2andv£星㌘H）3correspondtothemaximumgrowthrateofO2，

NO訂，MnO2andFe（OH）3reducingbacteria，Vxldec，Vx2decandvx3decCOrreSPOndtotheconstant

decayrateofbacteriaXl，X2andX3，F（02bi。）istheswitchingfunctionparameter，02th，eSis

thethresholdconcentrationofO2，んistheslopeofswitchfunction，［02］bi。，［NO言］bi。and

［CH20］bi。COrreSpOndtoconcentrationofO2，NOtandCH20inthebiophase．Kb2，Kv。5and


‰20COrreSpOndtohalfvelocityconcentrationofO2，NO訂andCH20inthebiophase．

Thebacteriaareassumedtoconsumedissolvedoxygen（DO）aslongasitisavailable andthenswitchtonitrateaselectronacceptor．Theswitchingbetweenaerobicanddenitrify－

ing growth conditionsis based on the assumption of a non－COmpetitiveinhibition andis

realizedbyaweightingfunctionF（02bi。）dependentontheoxygenconcentration，Whichwas

developedandtestedbyKinzelbach，etal．（1991）．Equation（22）isbasedontheassumption

thatthesamemicroorganismsarecapableofeitheraerobicordenitrifyinggrowth，depending

On the oxygen concentrationin their nearby environment．It allows adjustment of two

Characteristicfeaturesofthemicrobialswitching，theslopeんandthethresholdconcentra－

tionofoxygenO2th，eS，aCCOrdingtolaboratoryorfieldmeasurements．Itisalsoassumedthat

the functionalbacterialgroup Xlreduces nitrate quantitatively to N2under anaerobic

COnditions．This biochemicalmodelis mathematically similar to other models that use

Monodtypekineticstodescribemicrobialactivity（e．g．Schaferetalリ1998；Widdowsonet

al．，1998；Kinzelbachetalリ1991；KindredandCelia，1989）．

6．Mode11iIlgMethodology

Theone－dimensionalsolutetransportequationissolvedforeachchemicalspecies．The

modelcouplestheflowequationwiththesolute－tranSpOrtequation．Theflowandtransport

equationarediscretizeduslngareCtangular，uniformlyspaced，blockcentered，finitediffer－

encegrid．Sinceartificialoscillationandnumericaldispersionareencounteredinthefinite

differencemethodwhenappliedtoadvection－dominatedproblem，themethodofcharacteris－

tics（MOC）was used to eliminate numericaldispersion（Zheng and Bennett，1995）．The

iterative numericalprocedure employed for coupling of physicaltransport and chemical

PrOCeSSeSWaSbasedonMomiietal．（1997）．Themulticomponentsolutetransportmodelis

applicable for one－dimensionalprobleminvolving steady－State flow．The modelcomputes

Changesinconcentrationovertimecausedbytheprocessesofadvection，dispersion，Cation

exchangereactionsandbiochemicalreactions．

7．Parameter Estimation

Themodellingofmulticomponentsolutetransportwithbiochemicalreactionprocesses

iscomplexbecauseitinvolvesspecificationofmanybiochemicalparameters．Monodkinetic

ParameterSforheterotrophicprocesseswereselectedfollowingareviewofseveralstudies

relatedtowastewatertreatmentmodelingandsimulationofdenitrificationingroundwater

（Kinzelbachetal，1991；Lensingetal，1994；Schaferetal，1998；Hiroshiroetal，1999）．Table

6showsthedifferentbiochemicalparametersusedinthesolutetransportmodel．Ingeneral

theseparametersareaffectedbytemperature．Thetemperatureeffectonthedenitrification

rateisanimportantfeatureinthedesignofdenitrificationprocess．Carrerraet al．（2003）

Studiedtheinfluenceoftemperatureondenitrificationofanindustrialhigh－Strengthnitrogen

WaSteWaterinatwo－Sludgesystem andfoundoutthatthemaximumdenitrificationrateis

muchhigherat250C．Themostfavorabletemperaturefordenitrificationrangesfrom200C

to300Candtheaveragetemperaturemeasuredinthepresentexperimentishighenoughat

300C．Consequently，theparametersadjustedforthisparticularsimulationmaybethecase

forthemostdesirabledenitrification．Inthisstudy，themaximumgrowthrateofbacteria

Xl，γ£邑Ⅹand v去慧was calibratedby trialand error methoduntilthe O2and NO言in the

Simulationmodelfit themeasuredconcentrationofO2andNO訂．

89 Solute Transport Model with Cation Exchange under Redox Environment

Table6 Parametersusedforthesimulation．

0．02

0．48

0．50

50day－1 0・005day－1

0．00005day

Specificvolumeofbiophase（叫血）

SpeciBcvolumeofmobilephase（nm。b） Specificvolumeofmatrixphase（nm。t）

Exchangecoefficient （α）

Exchangecoefficient（β）

Exchangecoe抗cient（Y）

SwitchingfunctionparameterF（02bi。）

ThresholdconcentrationofO2（02，h，eS）

Slopeofswitchfunction仏）

InhibitionConstantIC Nq－

Halfvelocityconcentration，K

HalfvelocityconcentrationofO2・Ko 2

HalfvelocityconcentrationofNO3－，KNO，－

HalfvelocityconcentrationofMnO2，KMhO2

HalfvelocityconcentrationofFe（OH）3，K 叫叫，

HalfvelocityconcentrationofCH20，KcH＄0

Ⅹ1－0ⅩygenReducingBacteria

YieldCoefficient桜。

Maximumgrowthratev慧

Constantdecayratevxl血

Xl－NitrateReducingBacteria

YieldCoefBcientl温

Maximumgrowthratev慧．

Constantdecayratevxl＆。

X2－ManganeseReducingBacteria

YieldCoefncienti器

Maximumgrowthratev㌘2

mnstantdecay一紙evズヱ。－亡

X3－IronReducingBacteria

YieldCoefficienti浣欝）3

Maximumgrowthratev慧0”）3

0．015mmol／1

40

0．01mmol／1

0．001mmol／1

0．001mmol／1

0．001mmol／1

0．001mmolノ1

0．10mmol／1

0．1mmoIcell－qmOlOC

5・Oday－1

0・75day－1

0．081mmoIcell－C／mo10C

4．05d吋1

0．75day・1

0．015mmoIcell－C／molOC

O・75day－1

0・113day・1

0．01mmoIcell－C／molOC

O．50day－1

0．075day・1

0．48

0．01cm

13．52mmolα100g

l．2mmol／L

l．2mmol／L

l．2mmol／L

O．453mmol／L

O，0428mmol／L

Constantdecayratevx3虚e

Soil properties

Porosity

pispersivityαL

CEC

Selectivity Coefficients

Iら畑g

Kca／Mn 糧げe

Kca／Nこ

Kca瓜

90 G．GuERRA，K．JINNO，Y．HIROSHIRO and K．NAKAMURA

8．Results and Discussions

8．1Flowrateandpermeability

Figure3showstheflowrateinColumnAandColumnBarerapidlydecreasingduring

thefirsttendaysandthenaftertendaystheflowrateinColumnAisalmostthesamewith

theflowrateinColumnB．Theaveragevelocitywasobtainedbydividingtheflowrateby

thesurfaceareaofthecolumn．Itwasassumedthatthesteadystatewasattainedattheflow

rate of40ml／day．Thenthepore water velocity was determinedby dividingthe average

velocitybyporosity．Inthesimulationmodeltheporewatervelocitywasassumedconstant

（1／て打＝7．68×10r6cm／sec）sincethemodelconsideredonlythereducedlayerthatissaturated．

Figure4showsthepermeabilityinColumnAandColumnBarerapidlydecreasingduring

thefirsttwodaysandthenaftertendaysthepermeabilityinColumnAisalmostthesame

withthe permeabilityin Column B．The rapid decreasein permeability could be due to

clogglngOfthesoilporesasaresultofthegrowthofbacteria．Fromtheexperimentalresults

of flow rate and permeability，thereis no significant difference between Column A and

ColumnB．Similarresultscanbeexpectedwiththetwosoilcolumns．

ml/day FloⅥrRate 180

160

148

120

100

80

60

40

20

0

0 10 20 30 40 50

Time（days）

Fig．3 FlowrateinColumnsAandB．

Cm／5eC Permeability 4E－005

3．8E－005

3E－005

2．5E－005

2E－005

1．5E一朝5

1】ト005

5】ト006

0

0 10 2（） 30 」紺 50

Time（days）

Fig．4 PermeabilityinColumnsAandB．

SoluteTransportModelwithCationExchangeunderRedoxEnvironment 91

8・2 SimulationresultofDissoIvedOxygen，NO訂andCH20

Figure5showsthesimulationresultofDOconcentrationatthetop5cmofplowlayer

inthemobilephaseattheearlystage・DOconcentrationreducedatthetopO．5cmofthe

COlumnwhereDOconcentrationdecreasedto

ZerO after30hours．Figure6shows the

SimulationresultofNO訂COnCentrationinthe mobile phaseinthe column．Denitrification

OCCurredimmediatelyatthetopO．5cmofthe

COlumn where NO言 COnCentration was reducedtozeroafter31hours，followingthe

reductionofDO．Figure7showsthevertical

distribution of CH20concentration．CH20

COnCentrationdecreasedonlyatthetop2cm

of the column and then increased near to

Originalconcentration．CH20concentration

degradationisrelativelyfastatthetop2cm

Of the column，Where O2 COnCentrationis

readilyavailable．Onthe otherhand，CH20

degradationisveryslowatthedeeperdown－

StreamOfthecolumnwherebothO2andNO訂 COnCentrationareverysmall．

DOConcentration（meq／L）

0 0．1 0．2 0．3

△ ◇

△ ◇

△ ◇

ー⇔－1ヱhotlrS ・・－・△一川18hours

…・…☆・・24hours

－・・・∈ト2‘hollrS

－・・“（）・－・・－28bours

－」才一－－30hour5

◇ ◇ ◇ ◇

△ ◇

Fig．5 SimulationresultofDOconcen

tionin the column．

NitrateConcentration（meq／L）

0 0．1 0．2 0．3 0．4

CH20Concentration（meq／L）

4 6 8 10

■r－r一r一r二r r ”u 山u Hu Ⅶ二u t．u

O O O O O O －皿L山一h】b－nr皿

28468∧U

l12223

2

r

・。W輌

P

Fig・6 SimulationresultofNO訂COnCen－ Fig．7 SimulationresultofCH20conc

trationinthecolumn． trationinthecolumn．

＼J


8．3 Comparisonofobservedandcalculatedconcentration

Themulticomponentsolutetransportmodelwastestedbycomparingthe simulation resultswiththeresultsofthesoilcolumnexperimentbyuslngtheconcentrationofirject waterfromthesoilcolumnexperiment（Tablel）astheconcentrationofiI力ectwaterinthe simulationmodel．Itwasfoundoutthatthemulticomponentsolutetransportmodelwasable topredictthebehaviorofdifferentchemicalspeciesinthesoilcolumnappliedwithsecondary treatedsewagewater・Figure8showstheobservedcationconcentrationcorrelatedfairly wellwiththe calculatedcationconcentrations．K十concentrationshowed almost constant values．Na＋concentrationdecreasedwhile Ca2＋and Mg2＋concentrationsincreased atthe depth17cmanddepth20cmofthecolumnduetodesorptionofCa2＋andMg2＋byMn2十and Fe2＋．Figure9showsthecomparisonofobservedandcalculatedconcentrationsofNO訂， Mn2＋andFe2＋．NO言COnCentrationrapidlydecreasedatthedepth17cmduetodenitrifica－ ti。nWhileMn2＋andFe2＋concentrationincreasedduetodissolutionfromMnO2andFe（OH）3 duringinfiltrationthroughtheplowlayer．Thesechangesinconcentrationindicatedthat chemicalreactionshadoccurredinallpartsofthecolumn．

meq／L Column B meq仙 ColllmnB 25

20

15

10

5

0

25

20

15

10

5

0

0 10 20 30 48 50

Tile（血ys）

30 胡 50

Tile（血ys）

0 10 20

Fig．8 Comparisonofobservedandcalculatedcationconcentrationinthemobilephase・

Dep仙・20cm meq／L meq／L Por州SCup－Dep仙17cm

0 10 20 30 40 50

Time（days）

0 10 20 30 40 50

Time（days）

Fig．9ComparisonofobservedandcalculatedNO訂，Mn2＋andFe2＋concentration・


8．4 SimulationresultofCH20，MnO2andFe（OH）3COnCentrationinthebiophase

FigurelOshowsthesimulationresults ofthe temporalvariation of CH20，MnO2and

Fe（OH）3inthebiophase．CH20concentrationdecreasedduringthefirst5dayswhileMnO2

andFe（OH）3decreasedafter5daysduetoconsumptionofbacteria．Fig・ure11showsthe

Simulation results of the temporalvariation of Xl，Ⅹ2and X3bacteria concentration at

differentdepthsinthebiophase．ThemaximumgrowthofbacteriaXloccurredatthedepth

5cmofthecolumn，WherehighconcentrationsofO2，NOiandCH20arepresent．Bacteria

Xlincreasesrapidlyduringthefirst5daysduetopresenceofO2，NO訂andCH20concentraq

tionat the top5cm ofthe columnthen decreases rapidly due to decreased O2and NO訂．

BacteriaX2andX3increaseafter5daysandthendecreasegradually．BacteriaX3increases

higherthanbacteriaX2duetohigherconcentrationofFe（OH）3thanMnO2inthematrix Phaseandconsequentlyinthebiophase．

The result of the soilcolumn experiment and the solute transport modelproduced

interestingobservationsonthebehaviorofchemicalspeciespresentinthesecondarytreated

SeWage Water．The result of the numericalsimulation approximately agreed with the

experimentalresults．

CH20 ColⅧmn玉 CⅡ20 Col11mtL】さ

12

10

8

8

4

2

D

12

10

8

6

4

Z

O

0 10 20 30 48

Time（days）

0 10 之0 卸 40

Time（days）

Fig．10 TemporalvariationofCH20，MnO2andFe（OH）3atdifferentdepthsinthebiophase．

m仙曲L ColⅦmn8 mmol几 Col11mnB 0．3

0．25

0．Z

8，15

0．1

0．05

0

0．Z5

8．2

0．15

¢．1

0．05

0

0 10 即さ0 ヰ○ 紬

Time（day5）

0 10 之0 30 40 5（，

Time（days）

Fig．11Temporalvariationofbacteriaconcentrationatdifferentdepthsinthebiophase．

94 G．GuERRA，K．JINNO，Y．HIROSHIROandK．NAKAh／IURA

9．Design ofInfiltrationTreatment

In order to design the thickness of plowlayer thatis safe for nitrateleaching，itis

necessary to determine the depth where denitrification occurs．Denitrification has been

inferredfromtheobservationofdecreasingNO言COnCentrationandcorrespondingdeclinein dissolved oxygen concentration．Reduction of NO訂to N2by organic matter under anoxic

conditions as a result of denitrificationin soilsis welldocumented．A number of studies

（Trudelletal．，1986；MacQuarrieetal．，2001）haveshownthatreductionofNOi．byorganic

matteroxidationcanbeimportantinaquifers．AccordinglyKinzelbachandSchafer（1989）

modelNO言reductionbyorganicmatterinasandyaquiferusingthekinetic approachand found that the field data are welldescribedby reaction of NO言With degradable organic matterin sediments．

Thedesignofinfiltrationtreatmentisalsoprimarilyaffectedbytheapplicationrate．In

rapidinfiltrationsystems，therequiredtreatmentperformanceisofprimaryimportancein

determining the application rate．Lance and Gerba（1977）showed that decreasing the

applicationratefromthehydrauliclimitcouldresultinincreasedremovalsofconstituents，

especiallyNO訂．Sincethechiefmechanism ofNOiremovalinrapidinfiltrationsystemsis

denitrification and denitrificationrequires adequate detentiontime，anOXic conditions and

adequate organiccarbonto drivethereaction．Thereductionin applicationrateincreases

detentiontimeandincreasesthepotentialfordenitrification．

Inthis chapter the design ofinfiltrationtreatment consideredboththe effect of pore

Velocity andinput CH20concentration．The design of the thickness of plowlayeris

importantinlandtreatmentsystemdesignandoperation，SOaStOmaXimizelandtreatment

efficiencyandminimize operation andmaintenancecosts．

9．1EffectofporevelocitylⅧonNO言1eaching

Figure12shows the concentration of O2，NO訂and CH20at different depths of the

columnwhen VK＝7．68×10‾6cm／secandtheinputCH20was6．23mmol／Linthesimulation

model．NOiconcentrationwastotallyreducedafter2daysatalldepthsofthecolumn．02

andNO訂COnCentrationwerereducedduetoconsumptionofbacteriaXl．Figure13shows

theconcentrationofO2，NO言andCH20atdifferentdepthsofthecolumnwhenl／三好＝3．84×

10－5cm／secandtheinputCH20at6．23mmol／Linthesimulationmodel．Whenporevelocity

l／て打＝3．84×10－5cm／sec，NO訂COnCentration decreased after2days thenincreased after4

daysatdepths5cmandlOcmofthecolumn．NO言COnCentrationinfiltrateddeeperdownto

depthlOcmduetohighvelocityandlackofCH20concentrationtoreduceNOi．SinceCH20

inducesheterotrophicdenitrification，inwhichbacteriainanaerobicenvironmentusesNO6．

aselectron acceptorto oxidizedissoIvedCH20．LowconcentrationofCH20willresultto

NO6．infiltration．

9．2 Effect ofinject CH20concentration

Figure14shows the concentration of O2，NO6．and CH20at different depths of the

columnwhentheinput CH20is O．623mmol／L andpore velocityl／肯＝7．68×10dJ6cm／sec．

AgainNO訂COnCentrationdecreaseafter2daysthenincreaseafter4daysatdepths5cmand lOcmofthecolumn．NO訂COnCentrationinfiltrateddeeperdowntodepthlOcmduetolack

OfCH20concentrationtoreduceNO言．SinceCH20inducesdenitrification，lowconcentration

OfCH20willresulttoNOtinfiltration．Figure15showstheconcentrationofO2，NO6．and

CH20atdifferentdepthsofthecolumnwheninputCH20is62．3mmol／Landporevelocity

9,5 SoluteTransportModelwithCationExchangeunderRedoxEnvironment

CH2002，NO3 Depth - 5 cm. CH2002，NO3 Depth－5cm・ 12

10

＄

8

4

2

0

8．5

0．4

0．3

0．2

0．1

0

0．5

0．4

0．3

0．2

0．1

0

12

10

8

6

4

2

0

0 10 20 30 40 50

Time（days）

0 10 20 30 40 50

Time（days）

CHユ002，NO3 Depth－10cm・ CH2002，NO3 Dep也・10cm． 12

10

8

6

4

之

0

0．5

0．4

0．3

0．2

‡＝り

0

1Z

lO

8

6

4

2

8

0．5

D．4

0．3

0．2

0．1

0

8 10 20 30 40 50

Time（days）

0 10 20 30 48 50

Time（days）

CH2002，NO3 Deptll－20cm． CH200ヱ，NO3 Ⅰ）ep仙・20cm・ 12

10

8

8

4

2

8．5

0．4

0．3

0．2

0．1

12

10

8

6

4

2

0

0．5

0．4

0．3

0．Z

O．1

0

0 10 20 30 40 5D

Time（days）

Fig．12 Mobile redox concentration at

different depths when pore veloc－

ityl／肯＝7．68×10‾6 cm／sec and

inputCH20＝6．23mmol／L

0 10 20 30 40 58

Time（days）


different depths when pore veloc－ ity VK＝3．84×10山5 cm／sec and

inputCH20＝6．23mmol／L．

is VK＝7．68×10‾6cm／sec．NO訂COnCentration was totally reduced at a11depths of the

COlumnduetosufficientCH20concentration．CH20enhancedheterotrophicdenitrification，

in which bacteriain anaerobic environment uses NO言 as electron acceptor to oxidize

dissolvedCH20．CH20concentrationthenincreasesatdepth20cmduetolackofO2．This

effectis also dependent on the consumption of bacteria since thereis too much CH20

COnCentrationinexcess atthisdepth．


CII200ちNO3 Dep仙－5cm・ CH20 0ヱ，NO3 Dep仙－5cm・

8 10 ZO 30 40 50

耶me（days）

O iO 20 30 40 50

Ⅵme（days）

CHヱ002，NO3 Depth - 10 cm. CHヱ002，NO3 Ⅰ）q血－10cm． 0．5

0．4

8．3

0．2

0．1

0

12

10

8

6

4

之

0

8．5

0．4

0．3

D．Z

O．1

0

12

10

8

6

4

2

0 0 10 20 30 40 50

Time（days） 8 1（） 20 30 40 50

Ⅵme（days）

CH2002，NO3 Depth・ヱOcm・ CH2002）NO3 Depth - 20 cm. 0．5

0．4

0．さ

0．2

0．1

0

12

10

8

8

4

2

0

12

10

8

6

4

2

0

0．5

0．4

0．3

0．2

8．1

0

0 1（） 20 30 40 50

¶me（days）


different depths withinput CH20

0f62．3mmol／L andljK＝7．68×

10．6cm／sec．

0 1¢ 20 30 48 50

Time（days）


different depths withinput CH20 0f O．623mmol／L andl／て打＝7．68×

10．6cm／sec．

When theinput CH20in the simulation modelis O．623mmol／L，NO訂COnCentration

infiltrateddeeperdowntothedepths5cmandlOcmofthecolumn．Thesafedepthofthe

Plowlayerinthecolumn，WhereNO訂COnCentrationistotallyreduced，Canbedesignedby

takingintoconsiderationtheinputCH20concentrationattheinjectwaterandvelocityofthe

SOlute．

Table7showstheNOileachatlOcmdepthinrelationtoinputCH20concentrationand


Table7 NO訂1eachatlOcmdepthinrelationtoinputCH20concentrationandporevelocity tjK・

VK /Input CHzO CH20＝0．623mmol／L CH20＝6．23mmol／L CH20＝62．3mmol／L

Ⅵr＝7．68Ⅹ10‾bcm／SeC Noleach Noleach Noleach

VX≒1．92Ⅹ10‾）cm／sec Noleach Noleach Noleacb

l償≒3．84Ⅹ10‾3cm／SeC NO；LEAC NO3‾Ⅰ一EACH Noleach

porevelocity VK．Whenl／肯is7．68×10‾6cm／sec andl．92×10‾5cm／sec，theplowlayer depthatlOcmissafeforNO訂1each．WhenlノK＝3．84×10q5cm／secandtheinput CH20 concentrationisO．623mmol／Land6．23mmol／L，theplowlayerdepthatlOcmisnotsafeas

NO訂Ieachoccurredafter4days．Whenporevelocityl／K＝3．84×10r5cm／sec，higherinput CH20concentrationatinjectwaterisneededsothatNO訂1eachcanbeprevented．

CH20isasignificantquantitybecausethegrowthofbacteriadependsonthepresence

ofCH20concentration．ThedistributionofCH20inthesoilcolumnanditsavailabilityto

microorganisms as dissolved organic carbon proved to be a good means to control the

distribution of bacteriain the model．In addition，CH20also enhances heterotrophic

denitrificationinwhichbacteriainanaerobicenvironmentusesNO訂aselectronacceptorto OXidizedissolvedCH20．HighconcentrationofCH20willresulttoNOi．reduction．

10．Conclusioms

Thedevelopmentanduseofmathematicalmodelsprovidesabetterunderstandingofthe

importantbiological，Chemicalandhydrologicalprocessesrelevanttocontaminanttransport・

Themulticomponentsolutetransportmodelwas abletopredictthebehaviorofchemical

speciespresentinsecondarytreatedsewagewaterunderredoxenvironment．Theobserved

concentrations correlated fairly wellwith the simulated concentrations．The modelre－

producedthesequentialreductionreaction．02WaSreducedfirstafter30hoursthenfollowed

byNO訂after31hours．

Implementationofwastewaterreusepromotespreservationoflimitedwaterresources・ Indesigningawastewaterreusesystem，itisindispensabletodevelopaneffectivetreatment

schemethatiscapable ofremovingNO言andothercontaminants．Itisrevealedthatthe

multicomponentsolutetransportmodelisusefultodesignthelandtreatmentsystemforNOi

removalfromwastewater．CH20isasignificantquantitybecausethereductionofNO訂and

growthofbacteriadependonthepresenceofCH20concentration．Whenporevelocityl／肯

＝7．68×10J6cm／sec andlて打＝1．92×10‾5cm／sec andinput CH20concentration are O．623

mml／Land6．23mmol／，theplowlayeratdepthlOcmisstillsafeasNOg．concentrationwas

totallyreduced．Withporevelocityl／て打＝3．84×10‾5cm／secandinputCH20concentrationat O．623mml／Land6．23mmol／L，theplowlayeratdepthlOcmisunsafeduetoNO訂COnCentra－

tionincreasedafter4days．SinceCH20canenhancedenitrification，1ackofCH20willcause

theNO訂toincreaseagain．Whentheporevelocityishigh，higher CH20concentrationat

injectwaterisneededsothatthelOcmplowlayerwillbesafe．Theresultsshowthatthe

multicomponentsolutetransportmodelisusefulforthedescriptionofthebiologicalchemical

processesandtransportphenomena．Futureexpansiontotwo orthreedimensionsofthe

modelis necessary to address reactive transport at the various scales．Moreover the


influence of the changein hydraulic conductivity due to bacterialgrowth can be very

interestingfocusofstudyinthefuture．

Acknowledgement

WegratefullyacknowledgeProf．KazutoshiSaekiandProf．ShinichiroWadafortheir

COntributions and usefulcomments．

References

l）Appelo，C．A．J．，andWillemsen，A．（1987）．Geochemicalcalculationsandobservationon

Saltwaterintrusions，Ⅰ．A combined geochemical／mixing cellmodels，Joumalqf

物dγ0わ紗，Vol．94，313－330．

2）Appelo，C．A．J．，Willemsen，A．，Beekman，H．E．and Griffione，J．（1990）．Geochimical

Calculationsandobservationonsaltwaterintrusions，II．Validationofgeochemicalmodel

Withlaboratoryexperiments，Joumal〆物dYt）l脚，Vol．120，225250．

3）Appelo，C．A．，andPostma，D．（1994）．Geochemistry，grOundwater andpollution，A．A．

Ba旅ema，Rotterdam．

4）Bear，J．（1972）．DynamicsofFluidinPorousMedia，AmericanELseuier，NewYork．

5）Bouwer，E．J．andCobb，G．D．（1987）．Modelingofbiologicalprocessesinthesubsurface，

肋ねγ立Zg抑Cβα犯d7セcゐ乃OJ（概ノ．Vol．19，769－779．

6）Burden，R．J．（1981）．Nitratecontamination of NewZealand aquifers：a reView，Neu）

ゑαわ乃dノb〟γ裾αJ〆5cZg〝Ce，Vol．25，205【220．

7）Carrera，J．，Vicent，T．andLafuente，F．J．（2003）．Influenceoftemperatureondenitrifica－

tionofanindustrialhigh－Strengthnitrogenwastewaterinatwo－Sludgesystem，一物ter

且4，Vol．29，11－16．

8）Dance，J．T．andReardon，E．J．（1983）．Migrationofcontaminantsingroundwaterina

landfill：Acasestudy，Joumal〆物dnlcm，Vol．63，109130．

9）Engesgaard，P．and Christensen，T．H．（1988）．A review of chemicalsolute transport

models，∧わrdic物droIcm，Vol．19，183－216．

10）Frind，E．0．，Duynisveld，H．M．，Strebel，0．，Botcher，］．（1990）．Modeling of

multicomponenttransportwithmicrobialtransformationingroundwater：TheFurhberg

CaSe，l侮ter Resources Researt：h，Vol．26，1707－1719．

11）Hiroshiro，Y．，Jinno，K．，Wada，S．，Yokoyama，T．，and Kubota，M．（1999）．

MulticomponentsolutetransportwithcationexchangeinaredoxsubsurfaceenvironJ

ment，CblibmtionandRelklbili＆in Grt）undwaterModeling（ProceedingsoftheModel－

CARE99conferenceheldatZurich，1999），474－480．

12）Hiroshiro，Y．，JinnoK．，Yokoyama，T．andWada S．I．（1999）．Behaviour ofchemical

SpeCies under reducing conditionin a subaqueous soils column，Lowhlnd7bchnology

加ゎγ乃α≠わ裾αJ，Vol．1，pp．59－66．

13）Kindred，J．S．and Celia，M．A．（1989）．Contaminant transport and biodegradation2．

Conceptualmodelandtestsimulations，t侮ter ResourcesReseanh，Vol．256，1149－1159．

14）Kinzelbach，W．andSchafer，W．（1989）．Couplingofchemistryandtransport，Ground－

WaterManagement，1AHSfWlications，Vol．188，237－259．

15）Kinzelbach，W．，Schafer，W．andHerzer，J．（1991）．Numericalmodelingofnaturaland

enhanceddenitrificationprocessesinaquifer，彷匂terResourt：eSResea7Th，Vol．27（6），1123－

1135．

16）Kubota，M．，Hiroshiro，Y．，Jinno，K．，Yokoyama，T．andWada，S．I．（1998）．Propertiesof


multicomponenttransportinasubsurfaceenvironment，ProceedingsoftheInternational

SymposiumonLowlandTechnology／SagaUniversity，487－494．

17）Lance，J．C．andGerba，C．P．（1977）．Nitrogen，phosphateandvirusremovalfromsewage

Waterduringlandfiltration，Prog77？SSiue t侮ter7セchno10gy，Vol．9，157－166．

18）Lensing，H．J．，Vogt，M．andHerrling，B．（1994）．Modelingofbiologicallymediatedredox

processesinthesubsurface，Journalqf物drologリ，Vol．159，125r143．

19）Liu，C．W．and Narasimhan，T．N．（1989a）．Redox－COntrOlled multiple species reactive

ChemicaltransportI．Modeldevelopment，t侮terResourcesReseayt：h，Vol．25（5），869¶882．

20）Liu，C．W．and Narasimhan，T．N．（1989b）．Redox－COntrOlled multiple species reactive

ChemicaltransportI．Verificationandapplication，t侮terResourresResea7rh，Vol．25（5），

883－910．

21）Mac Quarrie，K．T．B．and Sudicky，E．A．（2001）．Multicomponent simulation of waste－

WaterderivednitrogenandcarboninshallowunconfinedaquifersI．Modelformulation

andperformance，jbumalqf Conhlminan＝弧droIQgy，Vol．47，53－84．

22）MacQuarrie，K．T．B．，Sudicky，E．A．andRobertson，W．D．（2001）．Numericalsimulation

Of fine－grained denitrificationlayer for removing septic system nitrate from shallow

groundwater，Joumalqf Contaminant物drology，Vol．52，29u55．

23）Mc Nab，W．W．andNasarimhan，T．N．（1994）．Modelingreactivetransportoforganic

COmpOundsingroundwaterusingpartialredoxdisequilibriumapproach，t侮terResounes

斤e5gαⅣゐ，Vol．30，2619－2635．

24）Miller，C．W．and Benson，L．Ⅴ．（1983）．Simulation of solute transportin a chemical

reactive heterogeneous system：mOdeldevelopment and application，Wbter Resources

斤esgα汀ゐ，Vol．19，381－391．

25）MoIz，F．J．，Widdowson，M．A．andBenefield，L．D．（1986）．Simulationofmicrobialgrowth

dynamics coupledto nutrient and oxygentransportinporousmedia，t侮ter Resources

斤esgα作ゐ，Vol．22，pp．1207－1216．

26）Momii，K．，Hiroshiro，Y．，Jinno，K．andBerndtsson，R．（1997）．Reactivesolutetransport

Withavariableselectivitycoefficientinanundisturbedsoilcolumn，SoilScienceSocie砂

〆A∽gわcαノ0〝γ抑α／，Vol．61（6），1539－1546．

27）Polprasert，C．（1996）．OrganicWasteRecycling，John Wuey andSonsInc．，London．

28）Postma，D．，Boesen，C．，Kristiansen，H．，and LarsenF．（1991）．Nitratereductioninan

unconfinedsandyaquifer：WaterChemistry，reductionprocessesandgeochemicalmodel－

ing，t侮≠βγ月βSO〟作どぶ月βSgαⅣゐ，Vol．27（8），2027－2045．

29）Schafer，W．andTherrienR．（1995）．Simulatingtransportandremovalofxyleneduring

remediationofasandyaquifer，Journalqf Coniaminant qdnlw，Vol．19，205－236．

30）Schafer，D．，Schafer，W．and Kinzelbach，W．（1998）．Simulation of reactive processes

related to biodegradationin aquifersl．Structure of the three－dimensionalreactive

transportmodel，Journalqf Conhlminan＝弧drol（暖γ，Vol．31，167－186．

31）Schulz，H．D．and Reardon，E．J．（1983）．A combinedmiⅩing cell／analyticalmodelto

describetwo－dimensionalreactivesolutetransportforunidirectionalgroundwaterflow，

l侮～eγ月gso㍑Ⅳe5月eseα作ゐ，Vol．19，493－502．

32）Stumm，W．andMorganJ．J．（1981）．AquaticChemistry，John mlqy＆Sons hc．，New

York．

33）Trudell，M．R．，Gillham，R．W．andCherryJ．A．（1986）．Anin－Situstudyoftheoccurrence

andrateofdenitrificationinashallowunconfinedsandaquifer，Joumalqf L＆dro10gy，

Vol．83，251－268．

34）Vallochi，A．J．，Street，R．L．andRoberts，P．Ⅴ．（1981）．TransportofIon－eXChangingsolutes

ingroundwater：Chromatographictheoryandfieldsimulation，l侮terResourcesResearch，

100 G．GuERRA，K．JINNO，Y．HIROSHIRO andK．NAKAMURA

Vol．17，1517－1527．

35）VonGunten，U．andZobrist，J．（1993）．Biogeochemicalchangesingroundwaterinfiltra－

tionsystems：COlumnsstudies，Geochim Cosmochim Acia，Vol．57，3895r3906．

36）Widdowson，M．A．，MoIz，F．J．andBenefield，L．D．（1988）．Anumericaltransportmodel

foroxygen－andnitrate－basedrespirationlinkedtosubstrateandnutrientavailabilityin porousmedia，t侮ter Resources ReseaYt：h，Vol．24（9），1553－1565．

37）Zheng，Z．andBennet，G．D．，（1995）：AppliedContaminantTransport：Modelling，Theory

andPractice，l匂n Nostmnd Reinhold，NewYork．

multi-component solute transport model with cation ...64-1-6).pdf · uses fe（oh）3as electron...

Documents