反渗透浓水硬度与有机污染物的去除研究

反渗透浓水硬度与有机污染物的去除研究StudyonRemovalofOrganicPollutantsandHardnessfromReverseOsmosisConcentrate学科专业：市政工程研究生：王丽丽指导教师：顾平教授天津大学环境科学与工程学院二〇一二年十一月独创性声明本人声明所呈交的学位论文是本人在导师指导下进行的研究工作和取得的研究成果，除了文中特别加以标注和致谢之处外，论文中不包含其他人已经发表或撰写过的研究成果，也不包含为获得天津大学或其他教育机构的学位或证书而使用过的材料。与我一同工作的同志对本研究所做的任何贡献均已在论文中作了明确的说明并表示了谢意。学位论文作者签名：签字日期：年月日学位论文版权使用授权书本学位论文作者完全了解天津大学有关保留、使用学位论文的规定。特授权天津大学可以将学位论文的全部或部分内容编入有关数据库进行检索，并采用影印、缩印或扫描等复制手段保存、汇编以供查阅和借阅。同意学校向国家有关部门或机构送交论文的复印件和磁盘。（保密的学位论文在解密后适用本授权说明）学位论文作者签名：导师签名：签字日期：年月日签字日期：年月日摘要近年来，随着膜技术的快速发展，反渗透（RO）工艺作为主要的污水再生操作单元之一，在污水回用领域内占有了重要的地位。但伴随着RO浓水（ROC）的剧增，其中的难生物降解有机物和高盐度成为水处理领域急需攻克的难题，浓水若得不到妥善的处理而直接排放，必然会对土壤、地表水、海洋环境等产生不利影响。本课题针对天津某石化厂废水回用车间的RO浓水，采用造粒软化法和粉末活性炭（PAC）累积逆流吸附-微滤（MF）联用技术对其中的硬度和有机污染物进行了去除研究。造粒软化法较沉淀软化法具有提高药剂利用率、加速软化过程等优点。研究利用CaCO3作为晶种，NaOH为软化药剂去除RO浓水中的硬度。试验表明，投加晶种可以提高硬度的去除率，且出水浊度较低。当造粒30次后可认为晶种制备工作完成，试验在硬度去除率为70%前提下的最佳软化条件为NaOH投量为0.95g/L、晶种投加量为2g/L、180r/min搅拌30min后静置沉淀30min。粉末活性炭吸附-微滤组合工艺能够有效地去除RO浓水中的有机污染物，累积逆流吸附充分发挥了PAC的吸附容量。根据理论计算，在相同吸附效果下，累积二级逆流吸附比单级吸附可节约40%以上的PAC，本研究通过动态反应器试验验证了理论计算的正确性。RO浓水经处理后，出水的DOC和COD均能够接近出水目标值。该工艺在能够高效去除浓水中的有机污染物的同时节约炭的投加量，增加了工艺的经济性，具有良好的发展前景。连续曝气，间歇排炭和增大稀释因子可以有效地减轻微滤膜的膜堵塞与膜污染现象，减缓膜比通量的下降；运行结束后将膜进行化学清洗，膜比通量可以基本恢复。关键词：反渗透浓水；硬度；造粒；有机污染物；粉末活性炭；累积二级逆流吸附；微滤ABSTRACTInrecentyears,withtherapiddevelopmentofmembranetechnology,reverseosmosistechnologytookanimportantplaceinthefieldofwastewaterreuseasthemainwastewaterregenerationunitoperation.Butalongwiththedramaticincreaseinthequantityofreverseosmosisconcentrate(ROC),theproblemsoriginatedfromrefractoryorganicmatterandhighsalinityintheROCneededtobesolvedinthewaterindustryfield.Iftheconcentratedidnotproperlyhandledbeforeemission,itwouldinevitablyhaveanegativeinfluenceonthesoil,thesurfacewater,themarineenvironmentandsoon.Granulationsofteningmethodandpowderedactivatedcarbon(PAC)adsorption-microfiltration(MF)combinationprocesswereusedtoremovethehardnessandtheorganicpollutantsintheROC,witchcamefromapetrochemicalwastewaterreuseworkshopinTianjin.Granulationsofteningmethodcouldimprovetheutilizationofchemicals,acceleratethesofteningprocesscomparedwithprecipitationsofteningmethod.CalciumcarbonateandsodiumhydroxidewererespectivelyusedasseedcrystalandsofteningagenttoremovethehardnessoftheROC.Thetestshowedthatadditionofseedcrystalscouldincreasetheremovalrateofhardness,andtheeffluentturbiditywaslowaswell.Itwasconsideredthattheseedcrystalpreparationworkwasfinishedwhenthegranulationreached30times,thebestsofteningconditionofthetestwasthatthedoseofsodiumhydroxideandcalciumcarbonatewas0.95g/Land2g/Lrespectively,settlingof30minutesaftermechanicalmixingat180r/minfor30minutes,theremovalrateofthehardnesswouldreach70%inthiscondition.PACadsorption-MFcombinationprocesscouldeffectivelyremoveorganicpollutantsfromROC,thecumulativecountercurrentadsorptiongavefullplaytothePACadsorptioncapacity.Accordingtothetheoreticalcalculation,thecumulativetwo-stagecountercurrentadsorptionsavedmorethan40%ofthePACthansinglestageadsorptionoperationunderthesameremovalefficiencyoforganicmatter.Thetheoreticalcalculationwasverifiedbyalab-scalecolumn.TheresultsshowedthattheeffluentDOCandCODwereclosetothetargetvalue.ThisprocesscouldremovetheorganicpollutantsintheROCefficientlyandsavetheadditionofPACatthesametime,whichwouldimprovethecost-effectivenessoftheprocessandisofbetterapplicationpotential.Continuousaeration,intermittentdischargeofPACandincreasingthedilutionfactorcouldalleffectivelyreducethemembranefouling,andthenslowdownthedeclineofthespecificflux.Aftertheoperation,thespecificfluxofthemembranecouldbebasicallyrecoveredafterchemicalcleaning.KEYWOEDS：reverseosmosisconcentrate(ROC);hardness;granulation;organicpollutant;powderedactivatedcarbon;cumulativetwo-stagecountercurrentadsorption;microfiltration目录第一章绪论..................................................................................................................11.1课题背景与研究意义..............................................................................11.1.1课题背景.......................................................................................11.1.2研究意义.......................................................................................21.2反渗透浓水处理现状..............................................................................21.2.1反渗透及反渗透膜.......................................................................21.2.2反渗透浓水的水质特点...............................................................31.2.3国内外对浓水的处理方法...........................................................31.3水中硬度去除的研究现状......................................................................51.3.1水的硬度与软化目的...................................................................51.3.2水的软化方法概述.......................................................................61.4活性炭吸附与膜分离技术......................................................................71.4.1活性炭与活性炭的分类...............................................................71.4.2活性炭吸附机理及影响因素.......................................................71.4.3膜分离技术的发展现状...............................................................8