Effects-of-loading--resting-period--temperature--porous-media--vegetation-and

ChemicalEngineeringJournal181–182(2012)416–430ContentslistsavailableatSciVerseScienceDirectChemicalEngineeringJournaljournalhomepage:www.elsevier.com/locate/cejEffectsofloading,restingperiod,temperature,porousmedia,vegetationandaerationonperformanceofpilot-scaleverticalflowconstructedwetlandsAlexandrosI.Stefanakis,VassiliosA.Tsihrintzis∗LaboratoryofEcologicalEngineeringandTechnology,DepartmentofEnvironmentalEngineering,SchoolofEngineering,DemocritusUniversityofThrace,67100Xanthi,GreecearticleinfoArticlehistory:Received29July2011Receivedinrevisedform29November2011Accepted29November2011Keywords:ConstructedwetlandsVerticalflowLoadingrateRestingperiodTemperaturePorousmediaVegetationAerationOrganicmatterNitrogenPhosphorusabstractTenpilot-scale,cylindrical,verticalflowconstructedwetlands(area0.57m2)wereconstructedandoper-atedcontinuouslyforthreeyearsinparallelexperiments,treatingsyntheticwastewater,simulatingthefirsttreatmentstageoffull-scalesystems.Thewetlandunitswereplantedwithtwoplantspecies(i.e.,commonreedsandcattails),haddifferentporousmediamaterialcomposition(i.e.,carbonate,igneous,zeoliteandbauxite)andthreedifferenttotalsubstratethicknessesandgradations.Threeloading/restingscheduleswereused.Waterqualitysampleswerecollectedattheinletandtheoutletofeachunit,andwereanalyzedinthelaboratoryforthedeterminationofvariouspollutants.TheVFCWunitswerequiteefficientinorganicmatter(BOD5andCOD)andnitrogen(TKNandNH4+-N)removal,withmeanremovalefficienciesexceeding78%and58%,respectively.Meanphosphorus(TPandOP)removalwaslower(37%).Theunitswerefoundtoprovidesignificantpollutantremovalunderhighorganicloads,upto200gCOD/m2d.Thepresenceofreedsandaerationtubeswasfoundtoimprovetheperformance,whileplantspeciesdidnotaffectefficiency.Theuseofspecialmaterials,aimingatenhancingtheadsorptionofdifferentconstituents,didnotimprovethewetlandefficiency,probablyduetolimitedcontacttimebetweenmaterialandwastewater,andisnotrecommended.©2011ElsevierB.V.Allrightsreserved.1.IntroductionandbackgroundTheuseofna