污水处理工艺(英文文献)

EffectivenessofTreatmentTechnologiesforWastewaterPollutionGeneratedbyIndianPulpMillsDeepaK.Tiku&AnilKumar&S.Sawhney&V.P.Singh&RitaKumarReceived:11April2006/Accepted:26September2006/Publishedonline:13February2007#SpringerScience+BusinessMediaB.V.2007AbstractIndiahasalargenumberofpapermanu-facturingunits,withmillsvaryinginsizeofoper-ationsandtypeofproduct,scatteredalloverthelengthandbreadthofthecountry.Presentstudydealswiththesurveyoffourdifferentpulpandpapermills(MillA,MillB,MillCandMillD)inIndia,differingintheirscaleofoperationaswellasrawmaterialusage.Physico-chemicalcharacterizationofwaste-watersproducedbydifferentprocessingunitslikedigestorhouseliquors,bleachingsection,papermachinebackwaters,combinedinlettotheETPandoutlettoETP,forallthefourmills,wasconducted.DifferentparameterslikepH,Color,COD,BOD,percentNa,SAR,TDSandTotalhardnesswereanalyzedandcompared.Highlysignificantdiffer-enceswerethusfoundbetweenalltheprocessingunitsofallfourmillswithpvalues0.01.Thisevaluationshowedthatthoughthesemillshaveeffluenttreatmentfacilitiesinstalledintheirpremises,improvementsarestillneededtoincreasetheirefficienciesfortreatingthedischargedwastewaters.KeywordsBOD.COD.Paper.Pulp.TDS1IntroductionPulpandpaperindustryisquiteoldinIndia,withabout406registeredpulpandpapermills,havinganaverageinstalledcapacityofabout4.3milliontonsperannum(Nagarathanammaetal.1999).Outofthese,only34millshaveaninstalledcapacityofmorethan100tpd(tonsperday)andcanbecalledthelarge-scalepapermills;120millshaveacapacityintherangeof30–100tpdandtherest252mills,haveaninstalledcapacitylessthan30tpd(BajpaiandBajpai1994;Makhijanietal.1996).Thoughthetraditionalrawmaterialremainswoodandbamboo,however,duetogrowingconcernoverthediminish-ingforestcover,otherwoodyandnon-woodymaterialsarealsobeingputtouseformanufacturingpaperandrelatedproducts.Theseinclude;agriculturalresidueslikebagasse,hemp,riceandwheatstraw,cottonrags,wastepaper,etc.Sometimescottonragsarealsousedasasourceofcellulose(Thompsonetal.2001).EnvironMonitAssess(2007)132:453–466DOI10.1007/s10661-006-9548-3D.K.Tiku:A.Kumar:R.Kumar(*)EnvironmentalBiotechnologyDivision,InstituteofGenomicsandIntegrativeBiology,506,InstituteofGenomicsandIntegrativeBiology,MallRoad,Delhi110007,Indiae-mail:[e-mail]y,UniversityofDelhi,NorthCampus,Delhi110007,IndiaV.P.SinghAppliedMicrobiologyandBiotechnologyLaboratory,DepartmentofBotany,UniversityofDelhi,Delhi110007,IndiaThisindustrydischargesmillionsoftonsofhighlypollutingeffluentintotheaquaticenvironment,eachyearwithvaryingeffects(Lacorteetal.2003;Oraletal.2005).Negativeimpactsonwaterqualityincludeincreasesinturbidity,color,nutrientloadsandadditionoftoxicandpersistentcompounds(Kirkwoodetal.2001).Theindustryconsumeslargevolumeofwater,nextonlytoagricultureandisalsocountry’ssixthlargestconsumerofenergy(AliandSreekrishnan2001).Theratioofwatertopollutantsishigh.Forthisreason,usuallylarge-sizepapermillsarelocatedneartheperennialwatersources.KraftpulpingisthemostcommonlyemployedpulpingtechniqueinIndia,whichutilizessodiumhydroxideandsodiumsulfidefordissolvingthelignincomponentofwoodtoseparatethefibresforpaper-making(BajpaiandBajpai1994;Mehnaetal.1995).Theeffluentsemanatingfromthistypeofpulpinghavecharacteristicallyhighlevelsofbiochemicaloxygendemand(BOD,chemicaloxygendemand(COD),suspendedsolids,colorandorganiccom-pounds(AliandSreekrishnan2001).Notwopapermillsdischargeidenticalwaste-waters.Duetothediversityinusageofrawmaterials,scaleofproductionandeffluenttreatmentstrategies,thereisawidevariationinthedischarges(Thompsonetal.2001).Whilelargermillshaveaninfrastructureforrecoveryofchemicalsfromthespentliquor,itiseconomicallynon-viableforthesmallermillstooperatesuchchemicalrecoverysystems(AliandSreekrishnan2001).Asaresult,thesmallscalepapermillsandseveralmediumsizedmillsareconsideredtobemorepollutingsincetheydischargetheireffluentsgeneratedfrompulpingandbleachingsections,directlyintothereceivingwaterbodies(Jivendra1993).Consideringtheextremediversityandcomplexityofthepulpandpapermilleffluentsandthepaucityofsuitabletechnologiesforefficientbioremediationtechnologiesforthesame,itwasimportanttoassesstheactualloadofpollution,intermsofselectparameters,exertedbyeachindividualprocessingunitofmillsdifferinginrawmaterialutilizationaswellasscaleofoperation(PokhrelandViraraghavan2004).Thepresentstudyshowsanoverviewofthecharacteristicsofwastewateremanatingfromdiffer-entprocessingunitsoffourdifferenttypesofIndianpulpandpapermillsaswellaseffectivenessoftheireffluenttreatmentfacilities,throughcomparisonofdataobtained.Thedatawouldbeusefulindevelop-inginnovativebioremediationtechniquesformostpollutedindustries.2MaterialsandMethods2.1Milldescription2.1.1DescriptionoftheindustrialunitsFourdifferentmills,hereafterdesignatedasMillA,B,CandD,varyinginscaleofproductionaswellasrawmaterialsutilizedforpulpandpaperproductionweresurveyedascasestudiestounderstandtheextentofpollutionloadexertedbyeachofthem.MillAandCareamongthelarge-scalepapermills;MillBisamongthemediumscaleindustries,whereasM