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JournalofHazardousMaterials170(2009)954–961ContentslistsavailableatScienceDirectJournalofHazardousMaterialsjournalhomepage::AcasestudyIvanaGrˇci´ca,DinkoVujevi´ca,JosipˇSepˇci´cb,NatalijaKoprivanaca,∗aDepartmentofPolymerEngineeringandOrganicChemicalTechnology,FacultyofChemicalEngineeringandTechnology,UniversityofZagreb,Maruli´cevtrg19,HR-10000Zagreb,CroatiabDINAPetrokemijaInc.,Bjaniˇzov1,HR-51513Omiˇsalj,CroatiaarticleinfoArticlehistory:Received6April2009Receivedinrevisedform13May2009Accepted14May2009Availableonline21May2009Keywords:IndustrialwastewatertreatmentAdvancedoxidationprocesses(AOPs)FentontypeprocessesBox–Behnkendesign(BBD)Desirabilityfunctionapproach(DFA)abstractPre-treatmentofsimulatedindustrialwastewaters(SIM1,SIM2andSIM3)containingorganicandinor-ganiccompounds(1,2-dichloroethane,sodiumformate,sodiumhydrogencarbonate,sodiumcarbonateandsodiumchloride)byoxidativedegradationusinghomogeneousFentontypeprocesses(Fe2+/H2O2andFe3+/H2O2)hasbeenevaluated.TheeffectsofinitialFe2+andFe3+concentrations,[Fe2+/3+],typeofironsalt(ferroussulfatevs.ferricchloride),initialhydrogenperoxideconcentration,[H2O2],onminer-alizationextent,i.e.,totalorganiccontent(TOC)removal,werestudied.Responsesurfacemethodology(RSM),particularlyBox–Behnkendesign(BBD)wasusedasmodellingtool,andobtainedpredictivefunc-tionwasusedtooptimizetheoverallprocessbythemeansofdesirabilityfunctionapproach(DFA).Upto94%ofinitialTOCwasremovedafter120min.Ferroussulfatewasfoundtobethemostappropriatereagent,andtheoptimaldosesofFe2+andH2O2forreducingthepollutantcontent,intermsoffinalTOCandsludgeproductionwereassessed.©2009ElsevierB.V.Allrightsreserved.1.IntroductionTheincreasinggrowthofworld’spopulationandrapidindus-trialdevelopmentcausetheformationofthehugeamountofwastewaterloadedwiththenumerousorganiccompoundsunac-ceptablefortheenvironmentandhumanhealthaswell.Inordertopreservetheenvironment,followingtheprinciplesofcleanerproductionandsustainabledevelopment,removaloftoxicandhaz-ardouscompoundsfromindustrialwastewaterpresentsagreatissue.Newdirectivesandregulationsdemandthenecessityforfindingtheoptimalsolutionofthetreatmentofsuchwastewater,inordertodecreaseconcentrationofhazardouscompoundsbel-lowthemaximalconcentrationprescribedbytheregulation.Thepurificationofwastewaterhasbeenconductedinordertoprotectnaturalresourcesandenablethepossibilityofreuseofthiswater,savingthefreshandnaturalwaterinthesametime,astheprior-ityofsustainabledevelopmentandenvironmentalprotection.Ingeneral,methodsfortheindustrialwastewatertreatmentcanbegroupedasbiological,physicalandchemicalmethods[1].Biologicalmethodshavethewidespreaduseforthetreatmentofmunici-palandindustrialwastewater.Despiteofthelotofadvantages,somepollutants,includingthemosttoxicorganiccompoundscan-notbedestroyedbybiologicaldegradationprocessesbecauseof∗Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail](N.Koprivanac).theirlowbiodegradability.Physicalmethodsofwastewatertreat-mentgenerallypresenttransferofpollutionfromonephasetotheother,oftenexpensiveandnoteco-efficient.Also,asecondarywastedisposalandadsorbentregenerationadditionallydecreasetheeconomicalefficiencyofwastewatertreatmentbyphysicalmethods.Analternativetotheconventionalwastewatertreatmentprocessespresentsadvancedoxidationprocesses(AOPs)thatcanbeappliedindividuallyorasapartofintegraltreatmentprocess.Theadvantageoftheseprocessesincomparisonwithconventionalwastewatertreatmentmethodsisthepossibilityofthecompletedegradationoforganicloadtowardswaterandcarbondioxide.AOPsincludetheformationofhighlyreactivespecies(radicals)underthechemical,electricalorradioactiveenergyandtheycanreactnon-selectivelywithpersistentorganiccompoundstransfer-ringthemintoby-productswhichcanbedegradedmuchmoreeasily[2].Theseintermediateshavehighoxidationpotentialandoneofthemostimportantishydroxylradical(2.8eV).Itcanattackanddestructorganiccompoundstowardswaterandcarbondioxide,i.e.,mineralization[3–5].Inordertoobtainthebalancebetweeneconomicalgrowthanddevelopment,legislativeandhealthyenvironmentanddrivenbythedesireforpreservingofthebeautifullocalenvironmentandecosystem,anapplicationofnewtechnologiesneedtobestudiedforpossibleimplementationinindustrialwastewatertreatment.Amongallkindofindustrialwastewaters,thoseonesoriginatingfrompetrochemicalindustriesareconsideredasverycomplexandhardtotreat.Theconstituentsofthepetrochemicalwastewatersare0304-3894/$–seefrontmatter©2009ElsevierB.V.Allrightsreserved.doi:10.1016/j.jhazmat.2009.05.060I.Grˇci´cetal./JournalofHazardousMaterials170(2009)954–961955highlyspecific.Therefore,eachwastewaterhastobecharacterizedextensivelyandviableprocessingtechnologieshavetobeevaluatedforthetreatment.OxidativedegradationbyusingFentonprocessappearedtobeefficientforthetreatmentofwastewatersevenathigherinitialorganiccontent[6,7].FentonprocessisbasedontheoxidationwithFentonreagentwhichpresentsanoxidativemixtureofhydrogenperoxideandferrousions(