ISPE 4.预处理选项

PRETREATMENTOPTIONS预处理选项4.PRETREATMENTOPTIONS预处理选项4.1INTRODUCTION简介Pretreatmentisallprocessstepsorunitoperationspriortothelast(final)watertreatmentstep.Pretreatmentisaseriesofunitoperationstomodifythefeedwaterqualitysothatitwillbeofadequatequalitytobefedtoafinaltreatmentstep.ThisfinalstepmaybeReverseOsmosis,Ultrafiltration,MultiorMixedBedDeionizationorDistillation.ThesefinalstepsarediscussedinChapters5and6.预处理是指最后（最终）水处理步骤之前的所有加工步骤或单元操作。预处理是一系列的单元操作，用来改善给水水质以使其水质足够好而进入终处理步骤。最终步骤可以是反渗透、超滤、多或混合床去离子或蒸馏。第5、6章中将详细讨论这些最终步骤。ReverseOsmosisisuniquesinceitcanbeapretreatmentstep,inadditiontobeingafinaltreatmentstep.ReverseOsmosisapplicationsinpretreatmentarediscussedinthischapterandChapter11,butReverseOsmosisasatechnologyisdiscussedinChapters5and6.反渗透很特别，因为它即可以是一个预处理步骤，另外还能是一个终处理步骤。本章和第11章将讨论反渗透作为预处理的情况，而将其作为一门技术的情况将在5、6章中详述。Theinitialsectionsofthischapterdiscusstheprocessdesign(programmingissues)forpretreatmentdesignincludingfeedwaterqualityandoutputwaterqualityfrompretreatment.Thechapterthendiscussestheselectionoftreatmentoptions(i.e.unitoperations)forfourgroupsofimpurities:本章的开始部分讨论预处理设计的过程设计（程序设计问题），包括给水水质和经过预处理后出来的水质。然后讨论针对四种杂质所做选择的处理选项（即单元操作）：•Controloffouling-removalofturbidityandparticulates浑浊度和粒子的除垢控制•Controlofscaling-removalofhardnessandmetals硬度和金属的除氧化皮控制•Removaloforganicsandmicrobiologicalimpurities有机物和微生物杂质的去除•Removalofmicrobialcontrolagents微生物防治因子的去除Pre-treatmentoptionsaresummarizedinFigure4-1attheendofthechapter.本章结尾处的图4-1中总结了预处理的可选方案。Thefinalsectionsofthechapterdiscusstheimportanceofanioncomposition/concentration,pH,materialsofconstruction,andpretreatmentsystemcontrol.本章的最后讨论了阳离子的构成/深度、pH、组成材料以及预处理系统控制的重要性。ThisdiscussionisbasedonthedescriptionofthesetechnologiespresentedinChapter11.这些讨论是建立在11章中出现的对这些技术的叙述基础之上的。4.2PROCESSDESIGNOFPRETREATMENT预处理的过程设计Processdesignofthepretreatmentsystemisthespecificationoftheunitoperationsorprocessstepstotreatthefeedwater.Typicalinformationincludesflowrates,temperatures,pressure,andcompositionofallstreams.DetailedmechanicaldesignoftheequipmentforagivenunitoperationorprocessstepisbeyondthescopeofthisGuide.预处理系统的过程设计是对处理给水的单元操作或加工步骤的规范。典型信息包括流速、温度、压力以及所有水流的组合。为给出的单元操作或加工步骤的设备做详细的机械设计不在此指南范围内。Theprocessdesign(programmingissues)forapretreatmentsystemmayinclude:预处理系统的过程设计（程序设计问题）可能包括：a)Requiredquantityandqualityofthewaterfromthefinaltreatmentprocess.经过终处理程序出来的必须的水量和水质。b)Temperatureconstraintsonthewaterusedinapharmaceuticalprocessandtheapproachtomicrobialcontrol.对用于制药工艺的水温和防治微生物所需的温度限制。c)Thefinaltreatmentoptionthathasbeenchosen,asthisdefinestherequiredwaterqualityleavingpre-treatment.已经选定的终处理选项，这就规定了离开了预处理步骤所需达到的水质。d)Qualityofthefeedwaterthatistheinputtothepretreatmentsystem(waterqualitytobevalidatedoveraoneyearperiod).预处理系统的给水水质（验证水质需要一年以上的期限）e)Differencebetweeninputwaterqualityanddesiredoutputwaterquality.Thedifferencedeterminesimpritiesthatmustberemovedbythepretreatmentsystem.Thedifferenceisdeterminedbyperformingamaterialbalance.Attentionshouldbepaidtoimpuritiesandminorcomponents.输入水水质和希望得到的输出水水质之间的差异。此差异确定了必须要用预处理系统去除的杂质。此差异是通过执行一个物料平衡来决定的。应当特别注意杂质和较小的组分。f)Pretreatmentoptionstoprovidethedesiredremovalofimpuritiesconsideringotherfactorssuchascapabilitiesofthelaborforce,economics,wastedisposal,environmentalconsiderations,validation,andtheavailablespaceandutilities.鉴于劳动力、经济、废物处理、环境因素、验证以及或用的空间和设施之类的因素，预处理选项要能理想地去除杂质。Inadditiontodefiningtheoptionsforremovalofimpurities,theapproachtakentomicrobialcontrolisanintegralpartoftheprocessdesignofthepretreatmentsystem.Considerationsinclude:除了规定去除杂质这一项以外，用于防治微生物的途径也是预处理系统过程设计需要整合的部分。考虑包括：a)IfthedrinkingqualitywatertothepretreatmentsystemcomesfromamunicipalityintheUnitedStates,itwilltypicallycontainchlorine,orchloramines,asamicrobialcontrolagent.InEurope,ozoneisthemorecommonmicrobialcontrolagent.Theconcentrationoftheagentshouldbesufficienttoprotecttheinitialstepsofthepretreatment.如果预处理系统的饮用水是来源于美国市区，那么它都会含有用作微生物防治因子氯或氯胺。在欧洲，臭氧是最普遍的微生物防治因子。因子的浓度应当足够用来防护预处理的最初步骤。b)Ifthequantityofmicrobialcontrolagentisinsufficient,additionalmicrobialcontrolagentmaybeaddedorprovisionmadetoperiodicallysanitizetheinitialequipmentinthepretreatmentsystem.Thisislikelyifwatercomesfromasourceotherthanamunicipality.Increasedmonitoringoffeedwaterandtheinitialstepsmaybewarranted.如果微生物防治因子的量不够，那么可以添加额外的微生物防治因子或者在预处理系统的首个设备进行定期消毒。如果水是来源于市政以外，这种情况是很有可能的。希望能够保证增加对给水和最初步骤的监控。c)Atsomepointinthepretreatmentprocess,themicrobialcontrolagentmustberemovedbeforegoingtothefinaltreatment.Atthispoint,ameansofeithercontinuousorperiodicsanitizationneedstobeselectedforthetreatmentstepsfollowingthisremoval.在预处理过程的某些点上，进行终处理前必须去除微生物防治因子。在这种点上，必须为去除之后的步骤选择连续或定期消毒两种方式其中之一。TheUSPrequirementthatcompedialwatersshouldcontain“noaddedsubstancd”eliminatesadditionofchemicalstoPurifiedWaterorWaterForInjection.However,additionofchemicalagentsisnotprohibitedinpretreatment.Substancesarefrequentlyaddedinpretreatmentandsubsequentlyremovedinthepretreatmentorfinaltreatment.Someexamplesare:USP规定法定水应当含有“非添加物质”，这就排除了向“纯化水”或注射用水中添加化学物质的可能性。但是，在预见处理中并不禁止添加化学助剂。预处理时经常会加入一些物质，而它们又会在预处理或终处理中被去除。比如：•Chlorine(tocont