摘要电镀是世界三大污染行业之一，随着我国乡镇电镀企业的迅速发展，我国的电镀污染问题日趋严重。本文首先阐述了我国电镀废水的污染现状以及对人类产生的危害，在对化学处理、离子交换、电解法、生物处理等电镀废水处理方法的分析和比较后，结合乡镇电镀企业要求工艺简单、成本低等特点，决定采用NaHSO3化学还原沉淀法处理该企业的含铬、锌废水。本工艺是在pH=2.5时用NaHSO3溶液将Cr6+还原为Cr3+，在用NaOH溶液调节pH=8后生成Cr(OH)3和Zn(OH)2沉淀，在添加絮凝剂PAM后生成的絮体在斜板沉淀池中沉淀，出水经过滤器过滤后可回用于过滤器反冲洗水及各种溶液的配制，或者达标排放，而污泥则统一交于专业的环保公司处理。在设计中采用了较为先进的ORP测定仪、在线pH计和液位计实现反应过程的自动控制。通过设计计算确定了各构筑物的尺寸以及设备的选型，并对设计和操作管理中的要求进行了说明，最后对电镀废水治理的前景进行了展望。关键词：电镀废水；Cr；ZnABSTRACTWiththespeedydevelopmentoftheelectroplatingenterpriseintownsinourcountry,electroplatingindustry，asoneofthebiggestpollutionsintheworld,causesthepollutionmoreandmoreseverely。Inthispaper,describesthepresentsituationoftheelectroplatingeffluentwaterpollutionandthegreatharmitmakestothehumankindhasbeendescribed.Aftertheanalysesandthecomparisonofdifferentwaysfortreatmentofelectroplatingeffluentsuchaschemicaltreatmentprocess、ionexchangeprocess、electrolyticmethodandbiologicalprocess,IdecidetoadopttheNaHSO3reduction-precipitationtotreatthewastewatercontainingCrandZnforthecorporations,consideringthefeaturesofthetownelectroplatingcorporations'demandsofsimpletechniques,lowcosts,etc.ThistechnologyistodeoxidizeCr6+intoCr3+byNaHSO3solutionatthepH=2.5,thenadjustthepHto8withNaOHsolutiontomakeCr(OH)3andZn(OH)2sediment.Theflocculatingconstituent,formedafteraddingtheflocculatingagentPAM,canbedepositedintheslopingplanksettlingtank.Thewaterleftafterfiltratingthroughasankfiltercanberecycledasthebackwashofsankfilterandbeusedinconfectingvarioussolutionsorbedischargedanemissionstandard.And,thesludgecanbesolvedbytheprofessionalenvironmentalprotectingcompanies.ItadoptssomerelativelyadvancedequipmentsuchasmeasuringelementofORP、pHmeterandcontentgaugerealizetheautomataofthereactionprocess.Throughelaboratedesignationandcalculation,thesizeofeachconstructandthetypeelectionoftheequipmenthavebeenascertained.Besides,withexplanationsaboutthedesignationandthedemandsintheoperatingmanagement,itfinallycomestotheprospectofsolvingtheproblemofthewastewaterfromplating.Keyword:electroplatingeffluent;chromium;zinc目录第一章电镀行业环境保护现状...................................................................-1-1.1中国电镀行业概况.................................................................................................-1-1.2电镀污染现状.........................................................................................................-1-1.3电镀废水的危害性.................................................................................................-3-1.4电镀废水处理方法.................................................................................................-5-第二章设计背景...........................................................................................-9-2.1项目概况和意义.....................................................................................................-9-2.2设计条件...................................................................................................................
