印染废水处理论文外文翻译 6页

本文由xukexin0601贡献doc文档可能在WAP端浏览体验不佳。建议您优先选择TXT，或下载源文件到本机查看。十八章外文翻译印染废水处理论文摘要：本文分析了印染废水处理的所面临的问题，以及介绍了印染废水处理方法的研究进展与动向。并指出不同印染废水处理方法的组合是印染废水处理的有效方法。关键词：印染废水；处理方法纺织印染工业作为中国具有优势的传统支柱行业之一，20世纪90年代以来获得迅猛发展，其用水量和排水量也大幅度增长。据不完全统计，我国日排放印染废水量为3000-4000kt，是各行业中的排污大户之一。加强印染废水的处理可以缓解我国水资源严重匮乏的问题，对保护环境、维持生态平衡起着极其重要的作用。1印染废水处理面临的问题1.1排放标准的日益严格随着社会经济的不断发展和人们环境意识的提高，我国加大了对印染污水的治理。根据《纺织染整工业水污染物排放标准》，除Ⅲ类污水排放指标变化不大外，国家增加了Ⅰ类和Ⅱ类污水印染废BOD、COD、色度、悬浮物、氨氮、苯胺类、二氧化氯等指标的排放限定。而印染废水水质一般平均为COD800-2000mg/L，色度200-800倍，pH值10-13，BOD/COD为0.25-0.4，因此印染废水的达标排放是印染行业急需要解决的问题。1.2印染废水处理难度增加1.2.1印染废水组分复杂印染废水是指印染加工过程中各工序所排放的废水混合而成的混合废水。主要包括：预处理阶段(如烧毛、退浆、煮练、漂白、丝光)排放的退浆、煮练、漂白、丝光废水；染色阶段排放的染色废水；印花阶段排放的印花废水和皂洗废水；整理阶段排放的整理废水。印染废水水质随原材料、生产品种、生产工艺、管理水平的不同而有所差异，导致各个印染工序排放后汇总的废水组分非常复杂。随着染料工业的飞速发展和后整理技术的进步，新型助剂、染料、整理剂等在印染行业中被大量使用，难降解有毒有机成分的含量也越来越多，有些甚至是致癌、致突变、致畸变的有机物，对环境尤其是水环境的威胁和危害越来越大。总体而言，印染废水的特点是成分复杂、有机物含量高、色度深化学需氧量(COD)高，而生化需氧量(BOD5)相对较低，可生化性差，排放量大。1.2.2印染废水处理方法的局限性80年代以前，我国印染废水的可生化性较高，CODcr浓度常在800mg/L以下，采用传统的生物与物化联合处理系统，出水即可达到排放标准。近二十年来，印染废水水质发生了很大的变化。传统的印染废水处理方法，如吸附、悬浮、过滤、混凝等具有设备简单，操作简便和工艺成熟的优点，但是这类处理方法通常是将有机物从液相转移到固相或气相，不仅没有完全消除有机污染物和消耗化学药剂，而且造成废物堆积和二次污染；生物法只能除去印染废水中的BOD，对于COD特别是有毒难降解有机物和色度的出去效果不明显。单一的处理方法已不能满足当前印染废水发展的要求。2印染废水处理研究进展与动向2.1传统方法和工艺的改进2.1.1吸附法吸附法特别适合低浓度印染废水的深度处理，具有投资小、方法简便、成本低的特点，适合中小型印染厂废水的处理。传统的吸附剂主要是活性碳，活性碳只对阳离子染料、直接染料、酸性染料、活性染料等水溶性染料具有较好的吸附性能，但是不能去除水中的胶体疏水性染料，并且再生费用高，使活性碳的应用受到限制。近几年，研究的重点主要在开发新的新的吸附剂以及对传统的吸附剂进行改良方面。2.1.2混凝法混凝法具有投资费用低、设备占地少、处理容量大、脱色率高等优点。混凝剂有无机混凝剂、有机混凝剂及生物混凝剂等。传统混凝法对疏水性染料脱色效率很高。缺点是需随着水质变化改变投料条件，对亲水性染料的脱色效果差，COD去除率低。如何选择有效的混凝脱色工艺和高效的混凝剂，则是该技术的关键。2.1.3化学氧化法化学氧化是目前研究较为成熟的方法。氧化剂一般采用Fenton试剂(Fe2,H2O2)、臭氧、氯气、次氯酸钠等。按氧化剂的不同，可将化学氧化分为：臭氧氧化法和芬顿试剂氧化法。臭氧氧化法不产生污泥和二次污染，但n是处理成本高，不适合大流量废水的处理，而且CODcr去除率低。通常很少采用单一的臭氧法处理印染废水，而是将它与其它方法相结合，彼此互补达到最佳的废水处理效果。汪晓军等[13]用臭氧-曝气生物滤池工艺处理模拟废水2.1.4电化学法电化学法具有设备小、占地少、运行管理简单、CODcr去除率高和脱色好等优点，但是沉淀生成量及电极材料消耗量较大，运行费用较高。传统的电化学法可分为电絮凝法、电气浮法、电氧化法以及微电解、电解内法等。国外许多研究者从研制高电催化活性电极材料着手，对有机物电催化影响因素和氧化机理进行了较系统的理论研究和初步的应用研究，国内在这一领域的研究还刚刚起步。2.1.5生物处理法生物处理法主要包括好氧法和厌氧法。目前国内主要采用好氧法进行印染废水处理。好氧法又分为活性污泥法和生物膜法。活性污泥既能分解大量的有机物质，又能去除部分色度，还可以微调pH值，运转效率高且费用低，出水水质较好，适合处理有机物含量较高的印染废水；生物膜法对印染废水的脱色作用较活性污泥法高。但是生物法存在着三个自身无法解决的问题：①剩余污泥的处里费用较高；②单一运用生物法己不能满足实际运用的需要；③有时需要在其前端加一道提高废水可生化性的预处理，提高了投资及运行成本。单一的好氧生物处理只能去除废水中的部分易降解的有机物，色度问题无法解决。为了降低消耗及去除废水中较难降解的有机污染物，出现了厌氧-好氧新型处理工艺和生物强化技术。厌氧-好氧法可先由厌氧过程中的产酸阶段，去除部分较易降解的有机污染物，将较难降解的大分子有机物分解为较简单的小分子有机物，再通过好氧生物处理过程进一步去除。厌氧-好氧法处理难生化降解的印染废水具有除污染效率高、运行稳定和较强的耐冲击负荷能力等特点。有研究报道，采用厌氧-好氧工艺处理印染废水，在进水CODcr为1085mg/L，BODS为315mg/L的情况下，二者的去除率分别可达83.9和76.2，再经硫化床自然氧化和混凝沉淀处理，去除悬浮物，排水可达排放标准。由于传统的生物方法对色度的去除往往不够理想，国内外许多学者致力于培育或改良高降解活性菌种用于印染废水处理，产生了生物强化技术。其机理为向废水处理系统中投加自然界中的优势菌种或通过基因组合技术产生的高效菌种，增强生物量，强化生物量的反应，以去除某一种或某一类有害物质为目的。目前，生物强化技术最普遍的应用方式是直接投加对目标污染物具有特效降解能力的微生物。2.2高新技术的应用和实践2.2.1光化学氧化法光化学氧化法由于其反应条件温和(常温、常压)、氧化能力强和速度快等优点。光化学氧化可分为光分解、光敏化氧化、光激发氧化和光催化氧化四种。目前研究和应用较多的是光催化氧化法。光催化氧化技术能有效地破坏许多结构稳定的生物难降解的有机污染物，具有节能高效、污染物降解彻底等优点，几乎所有的有机物在光催化作用下可以完全氧化为CO2、H2O等简单无机物。但是光催化氧化方法对高浓度废水效果不太理想。关于光催化氧化降解染料的研究主要集中在对光催化剂的研究上。其中，TiO2化学性质稳定、难溶无毒、成本低，是理想的光催化剂。传统的粉末型TiO2光催化剂由于存在分离困难和不适合流动体系等缺点，难以在实际中应用。近年来，TiO2光催化剂的搀杂化、改性化成为研究的热点。2.2.2膜分离技术膜分离技术处理印染废水是通过对废水中的污染物的分离、浓缩、回收而达到废水处理目的。具有不产生二次污染、能耗低、可循环使用、废水可直接回用等特点。膜分离技术虽然具有如此多的优点，但也存在着尚待解决的问题，如膜污染、膜通量、膜清洗、以及膜材质的抗酸碱、耐腐蚀性等问题，所以，现阶段运用单一的膜分离技术处理印染废水，回收纯净染料，还存在着技术经济等一系列问题。现在膜处理技术主要有超滤膜，纳米滤膜和反渗透膜。膜处理对印染废水中的无机盐和COD都有很好的去除作用。3结语随着排放标准的日益严格，各国学者在印染废水的处理技术方面进行了深入的探索。相信随着科学技术的不断进步，印染废水的处理工艺将逐渐完善，投资省、运行费用低、操作简单的处理技术将给印染废水的处理带来新的希望。DyeingWastewaterTreatmentAbstract:Thispaperanalyzesthetreatmentofdyeingnwastewaterissuesfacing,anddescribesmethodsofdyeingwastewatertreatmentprogressandtrends.Andpointedoutthatdifferentmethodsofdyeingwastewatertreatmentisacombinationofeffectivetreatmentofdyeingwastewater.Keywords:Dyeingwastewater;treatmentAsthetextileindustryhastheadvantageofoneofthetraditionalpillarindustries,the20thcenturywastherapiddevelopmentsincethe90s,itswaterconsumptionanddischargearegreatlyincreased.Accordingtoincompletestatistics,China'sdailydischargedyeingwastewatercapacity3000-4000kt,isthebigoneofthesewageindustry.Strengthentheprintinganddyeingwastewatertreatmentcaneasethesevereshortageofwaterresourcesissues,protectionoftheenvironment,maintainecologicalbalanceplaysaveryimportantrole.Aprintinganddyeingwastewatertreatmentproblems1.1,theincreasinglystringentemissionstandardsWiththedevelopmentofsocialeconomyandpeople'senvironmentalawareness,ourincreasedinvestmentinprintinganddyeingwastewatertreatment.Accordingto"textiledyeingandfinishingofindustrialwaterpollutantdischargestandards",inadditiontoclassⅢeffluentchangedlittle,thestateincreasedtheclassⅠandⅡdyeingwastewatereffluentBOD,COD,color,suspendedsolids,ammonia,aniline,Chlorinedioxideemissionlimitsandotherindicators.ThegeneralwaterqualityprintinganddyeingwastewateraverageCOD800-2000mg/L,chroma200-800times,pH,10-13,BOD/CODforthe0.25-0.4,soprintingisaprintinganddyeingwastewaterdischargestandardsintheindustryneedtosolvetheproblem.1.2Thedifficultiesinprintinganddyeingwastewatertreatment1.2.1componentsofcomplexprintinganddyeingwastewaterPrintinganddyeingwastewaterreferstotheprocessofdyeingprocesswastewaterdischargedbyeachprocessamixtureofmixedwastewater.Include:pre-processingstage(suchassingeing,desizing,scouring,bleaching,mercerization)emissionsdesizing,scouring,bleaching,mercerizationwastewater;dyeingstageofdyeingwastewaterdischarge;printingstageofwastewateranddischargeprintingsoapingwastewater;finishingstagesoffinishingwastewaterdischarge.Qualityprintinganddyeingwastewaterwithrawmaterials,productionvarieties,productiontechnologyandmanagementlevelvary,leadingtovariousprintinganddyeingprocesswastewaterdischargesummaryafterthecomponentisverycomplex.Withtherapiddevelopmentofindustrialdyesandfinishingtechnology,newadditives,dyes,finishingagentsinthedyeingindustry,beingusedextensivelyinrefractorytoxicorganiccontentaremoreandmore,andsomearecarcinogenic,mutation,resultingindistortionoftheorganicmatter,ontheenvironmentespeciallythewaterenvironmentofthreatsandhazardsisgrowing.Overall,theprintinganddyeingwastewaterischaracterizedbycomplexcomposition,organicmattercontentishigh,darkcolorandchemicaloxygendemand(COD),whereasthebiochemicaloxygendemand(BOD5)isrelativelylow,poorbiodegradability,emissionvolume.1.2.2thelimitationsofprintinganddyeingwastewatertreatment80yearsago,ourprintinganddyeingwastewaterbiodegradabilityhigher,CODcroftenconcentration800mg/Lthefollowing,usingthetraditionalbiologicalandphysico-chemicalco-treatmentsystem,effluentdischargestandardscanbeachieved.Pasttwodecades,waterqualityprintingandndyeingwastewaterhasundergonegreatchanges.Traditionalprintinganddyeingwastewatertreatmentmethods,suchasadsorption,suspension,filtration,coagulationandotherfeaturessimple,easytooperateandprocesstheadvantagesofmaturity,butsuchtreatmentisusuallytotransferorganicmatterfromliquidtosolidorgas,notonlydidnotcompleteeliminationoforganicpollutantsandconsumptionofchemicalsandpollutioncausedbywasteaccumulationandsecondary;biologicalmethodscanonlyremovetheprintinganddyeingwastewaterBOD,COD,especiallyfortoxicandrefractoryorganicsandcoloroutoflittleeffect.Singleapproachcannotmeetthecurrentrequirementsofthedevelopmentofdyeingwastewater.2PrintingandDyeingWastewaterTreatmentandTrends2.1traditionalmethodsandprocessimprovement2.1.1AdsorptionAssaysuitableforlow-depthtreatmentofdyeingwastewaterwithlowinvestment,whichissimpleandlowcost,suitableforsmallandmediumsizedprintinganddyeingwastewater.Traditionalactivatedcarbonadsorbentismainlyactivatedcarbononlycationicdyes,directdyes,aciddyes,reactivedyesandotherwater-solubledyehasgoodadsorptionproperties,butnotremovalofcolloidalhydrophobicdyes,andthehighcostofrenewablesothattheapplicationofactivatedcarbonislimited.Inrecentyears,researchfocusedmainlyonthedevelopmentofnewadsorbentsandnewadsorbentforimprovementonthetraditionalside.2.1.2CoagulationCoagulationwithlowinvestmentcosts,equipment,smallfootprint,processingcapacity,decolorizationrateandsoon.Coagulantsareinorganiccoagulants,organiccoagulantsandbiologicalcoagulant.Traditionalcoagulationdecolorizationefficiencyonhydrophobichigh.Itrequireschangewithchangesinfeedwaterqualityconditions,thedecolorizationeffectofhydrophilicpoor,CODremovalrate.Howtochooseaneffectivecoagulationprocessandefficientcoagulant,itisthekeytothetechnology.2.1.3ChemicalOxidationStudyofchemicaloxidationismorematureapproach.OxidantcommonlyusedFentonreagent(Fe2,H2O2),ozone,chlorine,sodiumhypochlorite,etc..Accordingtothedifferentoxidants,chemicaloxidationcanbedividedinto:ozoneoxidationandFenton'sreagentoxidation.Ozonationdoesnotproducesludgeandsecondarypollution,highcosts,however,notsuitableforlargeflowwastewatertreatment,andCODcrremovalrate.Seldomasingleozonetreatmentofdyeingwastewater,butwillcombineitwithothermethods,complementarytoeachothertoachievethebestwastewatertreatmenteffects.WangXiaojunetal[13]withozonebiologicalaeratedfilterwastewatertreatmentprocess2.1.4ElectrochemicalElectrochemicalmethodhastheequipment,small,smallfootprint,simpleoperationandmanagement,CODcrremovalrateandthebleachingofhighandgood,buttheprecipitationformationandconsumptionoflargeelectrodematerials,higheroperatingcosts.Thetraditionalelectrochemicalmethodscanbedividedintoelectricflocculation,electricfloat,electro-oxidationandmicro-electrolysis,electrolysiswithinthelaw.Manyforeignresearchersfromthedevelopingelectrodematerialswithhighelectrocatalyticactivitytoproceed,ontheorganicelectro-catalyticoxidationmechanismofinfluencingfactorsandamoresystematicapplicationoftheoreticalstudyandpreliminaryresearch,thedomesticnresearchinthisfieldhasjuststarted.2.1.5biologicaltreatmentBiologicaltreatmentincludeaerobicandanaerobicmethods.Currentlythemainmethodofdyeingwastewaterusingaerobictreatment.Dividedintoaerobicactivatedsludgeandbiofilm.Alargenumberofbothactivatedsludgedecompositionoforganicmaterial,butalsoremovesomecolor,youcanfine-tunethepHvalue,highefficiencyandlowcostofoperation,effluentqualityisbettersuitedtodealwithprintinganddyeingwastewaterwithhigherorganicmattercontent;biofilmdecolorizationofdyeingwastewaterthantheactivatedsludgeprocess.However,therearethreebiologicalmethodscannotsolveitsownproblems:①Departmentofresidualsludgeinhighercosts;②single-usebiologicalJicannotmeettheneedsofpracticalapplication;③sometimesnecessarytoaddafront-endtoimproveitswastewaterbiodegradabilitypretreatment,toimprovetheinvestmentandoperatingcosts.Onlyasingleaerobicbiologicaltreatmenttoremovepartofreadilybiodegradablewastewaterorganicmatter,colorcannotsolvetheproblem.Inordertoreduceconsumptionandwasteremovalmoredifficulttodegradeorganicpollutantsintheemergenceofanaerobic-aerobictreatmentprocessandthenewbiologicaltechnology.Anaerobic-aerobicanaerobicprocesscanstartwiththeacidproductionphasetoremovepartoftheeasilydegradableorganicpollutants,degradationofmacromoleculeswillbemoredifficulttodecomposeorganicmattertosimplerorganicmolecules,andthroughaerobicbiologicaltreatmentprocesstofurtherremove.Anaerobic-aerobictreatmentofbiodegradablewastewaterwasdifficultwiththeremovalofpollution,highefficiency,stableandstrongresistancecapacityandsoon.Studieshavereportedthatanaerobic-aerobicprocessofdyeingwastewater,theinfluentCODcrto1085mg/L,BODSto315mg/Linthecase,boththeremovalrateupto83.9and76.2,respectively,andthenbyfluidizedbednaturaloxidationandcoagulationtreatmenttoremovesuspendedsolids,wateruptoemissionstandards.Thetraditionalbiologicalmethodofcolorremovalisoftennotideal,manydomesticandforeignscholarsdedicatedtonurturinghigh-degradationactivityofbacteriaorimprovedtreatmentofdyeingwastewater,resultinginabioaugmentation.Themechanismforthewastewatertreatmentsystemtoincreasethedominantspeciesinnatureorproducedthroughgenetictechnologyandefficientcombinationofbacteria,increasedbiomass,enhancedbiomassresponsetoremovalofaparticularhazardoussubstanceorclassofpurpose.Atpresent,thebiologicaltechnologyisthemostcommonapplicationformdirectlytothetargetdosagedegradationofpollutantswiththeeffectsofmicroorganisms.2.2Theapplicationandpracticeofhigh-tech2.2.1PhotochemicalOxidationPhotochemicaloxidationduetoitsmildreactionconditions(ambienttemperatureandpressure),oxidationcapabilityandspeedadvantages.Photochemicaloxidationofdecompositioncanbedividedintolight,photosensitizationoxidation,lightexcitationoffouroxidationandphotocatalyticoxidation.Morecurrentresearchandapplicationofphotocatalyticoxidationis.PhotocatalyticoxidationcaneffectivelydestroysmanystructuralstabilityDidifficultytothedegradationoforganicpollutants,Juyouenergyefficiency,pollutionandotherdegradationChediadvantages,almostnalloftheorganicmatterinthenextKeYiGuangcompleteoxidationcatalystfortheCO2,H2OandotherinorganicJianDanmaterial.However,thephotocatalyticoxidationeffectofhighconcentrationsofwastewaterisnotideal.Onthephotocatalyticdegradationofdyesinthelightfocusedonthestudyofcatalysts.Which,TiO2chemicalstability,insolublenon-toxic,lowcost,isanidealphotocatalyst.Conventionalpowder-typeTiO2photocatalystseparationbecauseofthedifficultiesandshortcomingssuchasnotsuitableformobilesystems,itisdifficulttoapplyinpractice.Inrecentyears,TiO2photocatalystmixedtechnology,modificationofahottopic.2.2.2MembraneSeparationTechnologyMembraneseparationtechnologyofdyeingwastewaterbythepollutantsinwastewatertheseparation,concentrationandrecoveryofwastewatertreatmenttoachievethepurpose.Withnosecondarypollution,lowenergyconsumption,canberecycled,wastewaterreuse,etcdirectly.Althoughmembraneseparationtechnologyhassomanyadvantages,buttherearealsounresolvedproblems,suchasmembranefouling,membraneflux,membranecleaning,andacidresistantmembranematerial,corrosionresistanceandotherproblems,soatthisstagetheuseofasinglemembraneseparationtechnologyofdyeingwastewater,recyclingpuredyes,therearestilltechnicalandeconomicandotherissues.Nowmembraneultrafiltrationmembranetreatmenttechnologies,nano-filtrationmembraneandreverseosmosismembrane.MembraneTreatmentofdyeingwastewatersaltsandCODremovalareverygoodrole.3ConclusionWithincreasinglystringentemissionstandards,nationalscholarsintheprintinganddyeingwastewatertreatmenttechnologiesin-depthexploration.Webelievethatwiththecontinuousprogressofscienceandtechnology,printinganddyeingwastewatertreatmentprocesswillbegradualimprovement,investment,lowcost,simpleprocessingtechnologyWastewatertreatmentwillbringnewhope.1