Aninnovativeap省略atedbioreactorsMaheshMannac

AninnovativeapproachtominimizeexcesssludgeproductioninsewagetreatmentusingintegratedbioreactorsMaheshMannacharaju,PrabhakaranNatarajan,ArivizhivendhanKannanVillalan,MadasamyJothieswari,SwarnalathaSomasundaram,SekaranGanesan⁎DepartmentofEnvironmentalScienceandEngineering,CSIR–CentralLeatherResearchInstitute(CLRI),Adyar,Chennai20,IndiaARTICLEINFOABSTRACTArticlehistory:Received27April2017Revised21July2017Accepted31July2017Availableonline2August2017Thepresentinvestigationdealswithanapplicationofintegratedsequentialoxicandanoxicbioreactor(SOABR)andfluidizedimmobilizedcellcarbonoxidation(FICCO)reactorforthetreatmentofdomesticwastewaterwithminimumsludgegeneration.TheperformanceofintegratedSOABR-FICCOsystemwasevaluatedontreatingthedomesticwastewaterathydraulicretentiontime(HRT)of3hrand6hrfor120daysatorganicloadingrate(OLR)of191±31mg/(L·hr).Theinfluentwastewaterwascharacterizedbychemicaloxygendemand(COD)573±93mg/L;biochemicaloxygendemand(BOD5)197±35mg/Landtotalsuspendedsolids(TSS)450±136mg/L.TheintegratedSOABR-FICCOreactorshaveestablishedasignificantremovalofCODby94%±1%,BOD5by95%±0.6%andTSSby95%±4%withtreateddomesticwastewatercharacteristicsCOD33±5mg/L;BOD59±0.8mg/LandTSS17±9mg/Lundercontinuousmodeofoperationfor120days.ThemassofdrysludgegeneratedfromSOABR-FICCOsystemwas22.9g/m3.ThesludgevolumeindexofsludgeformedintheSOABRreactorwas32mL/gandinFICCOreactoritwas46mL/g.ThesludgeformedinSOABRandFICCOreactorwascharacterizedbyTGA,DSCandSEManalysis.Overall,theresultsdemonstratedthattheintegratedSOABR-FICCOreactorssubstantiallyremovedthepollutionparametersfromdomesticwastewaterwithminimumsludgeproduction.©2017TheResearchCenterforEco-EnvironmentalSciences,ChineseAcademyofSciences.PublishedbyElsevierB.V.Keywords:Sequentialoxicandanoxicbioreactor(SOABR)FICCOreactorDomesticwastewaterImmobilizedcellreactorIntroductionTheenvironmentalmanagementonliquidandsolidwastesgeneratedduetohumanactivitieshasbecomeincreasinglycriticalduetoincreaseinworldwidepopulationgrowth.Theaerobicbiologicalprocessinconventionalwastewatertreatmentsystemisthemajorunitoperationfollowedforthetreatmentofdomesticwastewater.However,theaerobicbiologicaltreatmentprocessgenerateshugequantityofsludgeowingtohighconcentrationofsuspendedsolidsandbiodegradableorganiccompoundspresentinthewastewater.Hence,anaerobicsystemhasbeenconsideredtoreducesludgeproductionandtherebytoeliminatesludgedisposalproblems(Vorosmartyetal.,2010;MungrayandPatel,2011;PontesandDeLemosChernicharo,2011).Manyintegratedanaerobicandaerobicbiologicaltreatmenttechnologieshavebeendevelopedforthetreatmentofdomesticwastewater(Watanabeetal.,2016).Theupflowanaerobicsludgeblanket(UASB)systemwasdevelopedfortheeffectivetreatmentofdomesticwastewater.AlthoughUASBtreatmentprocessiswidelypracticed,ithascertaindisadvantagessuchashighoperationcostandextensivefootprintrequirementandJOURNALOFENVIRONMENTALSCIENCES67(2018)67–77⁎Correspondingauthor.E-mails:[e-mail](SekaranGanesan).©2017TheResearchCenterforEco-EnvironmentalSciences,ChineseAcademyofSciences.PublishedbyElsevierB.V.Availableonlineat(Buntneretal.,2013;AbbasiandAbbasi,2012;Lucianoetal.,2012;Wangetal.,2014).Theglobalstandards,madestringentondisposalofwastewaterandsolidwaste(Verlicchietal.,2011),demandthedevelopmentofmoreefficienttreatmenttechnologiesthathavefeaturessuchasminimumfootprintrequirement,lesselectricenergyconsumptionandminimumsludgegeneration.ResearchershavedevelopedhybridUASBreactor,membranebioreactor(Linetal.,2012;Buntneretal.,2013;Qiuetal.,2013;Wangetal.,2014),aeratedbiofilter(Chungetal.,2016),sequentialbatchreactor(Moawadetal.,2009),down-flowhangingsystem(Tandukaretal.,2007),Chemoautotrophicactivatedcarbonoxidationsystem(Sekaranetal.,2007)etc.forthetreatmentofwastewater.Despitethesetechnologiesaddressefficientremovaloforganicpollutantsandtheygeneratehugequantityofsludge.Therearereportsonbiofilmreactorstoreducethesludgeproductionandlowoperationalcostfortreatmentofsewage(Tawfiketal.,2010,2012;Khanetal.,2015;Chatterjeeetal.,2016;Dengetal.,2016).Biofilmreactortechnologyhasbeenregardedasthesimplestindesign,flexibleinoperationandcompactinspacerequirementforthetreatmentofwastewater.Itservedasanaddedadvantageonfreelymovingcarriersinthereactortosupportbiofilmdevelopment(Ødegaardetal.,2000;Leyva-Díazetal.,2013).Thedesignandoperationofsequentialoxicandanoxiczonesinbiologicalreactorimprovedthenutrientsremovalandanoxiczonefacilitatedthesupportingareaforsludgedigestion(Weietal.,2013).Designaspectofthesequentialoxicandanoxicbiofilmreactorwithplasticmaterialascarriermatrixforbiofilmgrowthformsthenovelpartofthepresentinvestigation.Thebiofilmmovingbedreactorsareknowntoproducelessquantityofsludgethaninactivatedsludgeprocessesbecauseofthelongerfoodchainsinbiofilmsundercontinuousoperatingconditions(Zhangetal.,2017;Leyva-Díazetal.,2013;Qietal.,2014).Thesequentialoxicandanoxicbiofilmreactor(SOAB