电渗析处理焦化废水反渗透浓水的工程应用研究

结合某焦化废水深度处理与回用工程项目,考察了电渗析处理焦化废水反渗透浓水的状况和不同工艺参数对膜性能的影响,明确电渗析处理焦化废水反渗透浓水的脱盐率和能耗。结果表明,焦化废水反渗透浓水污染物对电渗析膜污染较重,可用1%稀盐酸洗涤恢复膜性能。2台电渗析膜堆串联组合处理焦化废水反渗透浓水,脱盐率和吨盐能耗随操作电压的增大而增大。固定操作电压为250 V,淡化液流量为9 m3/h,在此条件下膜堆脱盐率为51%,吨盐能耗为625 k W·h。     

电镀废水零排放工程实例

根据电镀废水水质的特点,对含氰废水、含油废水、含铬废水、含镍废水和含铜废水进行分类前处理后,与混排废水混合进行混凝沉降?MBR(膜生物反应器)法预处理,采用超滤和反渗透装置对废水作进一步处理实现回用,反渗透浓水则采用电渗析?MVR(机械式蒸汽再压缩)工艺实现脱盐后再次进入反渗透装置处理回用。工程实践表明,该系统的出水不仅满足《电镀污染排放标准》(GB 21900-2008)的“表3”要求,且能够作为生产用水回用至电镀生产线。     

印染废水深度处理及回用

针对印染纺织废水稳定回用系统的浓水处理和脱盐问题,选用预处理系统(臭氧-曝气生物滤池一体化装置+曝气生物滤池)和膜系统(超滤+反渗透)的组合工艺,对印染纺织废水进行深度处理及回用。预处理较佳的工艺运行参数为:曝气生物滤池气水比为5,有机负荷分别约为2.1、1.0 kg(COD)/m3.d,溶解氧质量浓度为3.8 mg/L,水温35～40℃;臭氧投加量为20～30 mg/L。二级生化出水经预处理系统后,出水COD质量浓度平均值可降至27.4 mg/L,浊度为4.2 NTU,SS为3.0 mg/L,氨氮0.7 mg/L,色度2倍,再经过膜系统深度处理,淡水出水pH7.4～7.9,电导率50～200μs/cm,总硬度2～10 mg/L,总碱度25～60 mg/L,膜系统产水达到回用标准。测定浓水pH7.3～8.3,色度32倍,CODCr45.7～97.9 mg/L,可直接达标排放,保证系统稳定运行。     

1种简易电去离子装置的建立及对含Cu~(2+)废水的处理

基于自制板柱结构电去离子装置,探讨了浓水室填充离子交换材料(树脂、离子交换织物)处理低Cu2+含量废水的效果。经过100h运行结果发现,在浓水室中填充离子交换材料能够促进离子迁移,提高电去离子能力和出水水质,同时可缓解阴离子交换膜浓室侧表面的沉淀现象;更长时间运行后也发现,阴离子交换膜和树脂的季铵盐基团转变为叔胺基团,催化水解反应,加剧了离子交换膜和树脂表面沉淀结垢,使电去离子效果恶化。     

1,3-丙二醇发酵液电渗析脱盐工艺的优化

研究了1,3-丙二醇发酵液电渗析脱盐过程中某些工艺参数,例如不同交联度离子交换膜的选择、不同碱离子发酵液以及原料液预处理方式等工艺对脱盐过程的影响。同时在前期实验的基础上,研究了淡浓室流速比、淡室流速和浓室初始浓度三因素对电渗析脱盐操作过程的影响,并利用正交试验对脱盐过程的工艺优化作了进一步的探讨。     

焦化废水膜法组合深度处理工艺设计与应用

针对煤化工企业焦化废水的二级生化出水可生化性差、含盐量与COD高,以及废水中包含多环芳香族化合物、脂肪族化合物等难生物降解污染物的特点,采用Fenton氧化+电渗析+超滤+反渗透膜法组合深度处理工艺对废水进行处理。运行结果表明,产水水质达到并优于《工业循环冷却水处理设计规范》(GB 50050—2007)中再生水水质要求,产水可作为厂区生产补充新水使用,废水回收率稳定达到75%。采用Fenton氧化与电渗析粗脱盐技术相结合的强化预处理设施,可以有效缓解反渗透装置的膜污染,延长反渗透膜的清洗周期至3个月。     

电渗析淡化器

电渗析是利用离子交换膜的选择透过性,在外加直流电场作用下,使淡水室中的离子迁移到浓水室中去,从而达到使水淡化的目的。电渗析技术应用很广,目前广泛应用于给水除盐。可以经济地用于苦咸水淡化(将     

浓盐水EDMB膜脱盐工艺中试研究

煤化工浓盐水成分复杂、难处理，是废水零排放的瓶颈。以山西焦化污水深度处理反渗透装置产出的浓盐水为试验对象，通过电渗析和EDMB膜处理相结合的工艺装置进行中试，其出水盐含量降至5g/L以下，同时产出了满足膜工艺和树脂工艺再生用的酸和碱，实现了焦化废水节能减排及资源化目标。     

纺织印染废水深度处理与回用实例

采用"一体臭氧曝气生物滤池+曝气生物滤池(BAF)"组合工艺,对纺织印染废水进行预处理,联合后续膜分离工艺以实现中水回用,处理水量为5 000 m3/d。设计运行条件下,臭氧曝气生物滤池最佳臭氧投加量为20-30mg/L,预处理系统出水COD<40 mg/L、BOD<10 mg/L、SS<10 mg/L、色度<4倍;反渗透产水可作为染整工艺用水,膜滤浓缩液可达标排放。工程实践证明,该联合工艺可实现对纺织印染废水的深度处理与高质回用,并解决了膜滤浓缩液的处理难题,具有推广应用价值。     

聚合物驱采出水降矿化度工艺选择

根据限制聚合物驱采出水作为配制聚合物用水的主要原因,提出选择一种经济有效的脱盐工艺来降低合聚污水矿化度.根据国内外已经成熟的脱盐工艺,其中包括离子交换、蒸发,冷冻,电渗析和反渗透等,对各个工艺实施要求及工艺可行性进行了评价,得出了电渗析和反渗透为可行工艺,但电渗析为更经济可靠的脱盐技术.     

工业废水电渗析过程中膜污染研究进展

综述了工业废水电渗析体系膜污染类型、性质、影响因素等的研究进展. 无机污染主要是Ca2+, Mg2+或其他高价离子在离子膜表面或内部形成的结垢现象,原理是极化或溶液过饱和形成沉淀. 有机污染是由蛋白、腐植酸、表面活性剂及大分子有机物在离子膜表面沉积或渗透到膜内部而形成,原因主要是带负电荷的有机物与阴膜荷正电基团的静电作用及带苯环有机物与基膜的亲和作用,其次是有机物分子大小与膜的网络结构的作用. 膜污染形成及其性质与施加电流、共存组分、温度、pH值和运行时间等密切相关,可造成离子膜导电性、离子交换容量、水含量和极限电流密度等减小,且有机污染对电渗析性能的影响比无机污染更严重. 由有机物凝胶层形成的膜污染可用电渗析膜污染指数定量描述.     

反渗透在电镀工艺和废水处理应用上的局限性

简单介绍了微滤、超滤、纳滤、电渗析等膜分离技术,重点分析了反渗透膜的要求以及影响其寿命的因素,讨论了废水处理用反渗透系统的配置问题,说明了电镀中适于反渗透技术应用的场合。讨论指出:反渗透仅对废水中的限排物起截留浓缩作用,所得浓废水还须用化学法等作二次处理;反渗透的适用场合有限且应具备相应条件。     

阴离子交换膜改性及抗污染性能研究进展

电渗析技术应用于工业废水脱盐时,废水中有机物及其它杂质组分等会造成膜污染,进而影响脱盐性能。电渗析膜污染防治对促进电渗析在工业废水处理中的应用有重要意义。相比于阳离子交换膜,阴离子交换膜更易形成有机污染,且更严重。阴离子交换膜污染主要由腐殖酸、牛血清蛋白、阴离子表面活性剂等有机物造成,污染过程主要受静电作用、亲和作用和几何因素的影响。膜改性提高阴离子交换膜的抗污染性能是电渗析膜污染防治的有效方法,目前已有许多有关膜改性提高阴离子交换膜抗污染性能的报道。膜改性方法主要有化学改性法、等离子体改性法、表面涂覆改性法、电沉积改性法、自聚合改性法及改进基膜结构法等。本工作对阴离子交换膜改性及抗污染性能的研究进展进行了综述,对不同改性方法的优缺点进行了分析和评价。这些改性方法能提高阴膜表面的负电荷密度和亲水性、降低膜表面粗糙度和基膜含水率等,因此可以改善阴离子交换膜的抗污染性能。然而,目前研究获得的改性阴离子交换膜仍存在修饰层不稳定、抗污染性能不理想和性能测试不系统等缺点,需进一步优化改性方法、改性工艺、组分修饰及性能测试等,以获得抗污染性能稳定且效果良好的改性阴离子交换膜。     

Removal of hardness in fermentation broth by electrodialysis

Lysine fermentation broth was desalinated by electrodialysis to reduce hardness concentrations as a pretreatment procedure for the purification and recovery of amino acids. Electrodialysis performance was investigated in terms of the rate of reduction in conductivity in dilute solutions and electrodialysis cell resistance for different ion exchange membranes at a constant current density. Among the membranes investigated in this study, membranes with high water content showed the better performance for hardness removal. Fouling experiments revealed that organics gave rise to fouling effects on the anion exchange membrane during demineralization of the lysine fermentation broth. The pulsed electric field with the half‐wave power enhanced the electrodialysis performances by mitigating membrane fouling in desalination of the lysine fermentation broth. This study successfully demonstrated the potential use of pulse power as an effective cleaning‐in‐place (CIP) method during electrodialysis of fermentation broth. © 2002 Society of Chemical Industry     

Desalination of fish meat extract by electrodialysis and characterization of membrane fouling

Fish meat extract (FME) desalination via electrodialysis (ED) was performed and the changes of important parameters such as membrane stack potential, brix, pH, and electrical conductivity were examined for a quantitative evaluation. The change of electrical conductivity in diluted or concentrated solutions showed that the mineral ions contained in the FME could be effectively removed. The characterization of membrane fouling indicated that the organic/ inorganic components deposited, respectively, on the surfaces of anion/cation exchange membrane and resulted in the increase of membrane electrical resistance. Ion chromatograph (IC) analysis showed that the main mineral ions, such as Na⁺ and Cl⁺ ions contained in the FME, were removed about 82.3% at an average current efficiency of around 77.9% via ED. By considering the removal rate of mineral ions and current efficiency, the feasibility of FME desalination via ED was proved.     

The effect of oilfield polymer-flooding wastewater on anion-exchange membrane performance

Polymer-flooding process is one of tertiary oil extraction technologies. It has stepped into industrialization application period in Daqing Oilfield (China) in recent years. It plays an increasingly important role in the oil exploitation, but around 60 million ton polymer-flooding wastewater is produced per day with oil extraction together. Therefore, the treatment and reuse of wastewater becomes very significant. Experiments show that the polymer-flooding wastewater can replace freshwater to be reused to confect polymer solution after removing total dissolved solids (TDS) by electrodialysis technology. This treatment technology can not only decrease environmental pollution resulted by wastewater discharge, but also achieve closed-circuit of polymer-flooding wastewater during crude oil extraction. It has significant effect for protecting environment and saving water resource. After carrying out lots of experiments in the lab, the pilot-test electrodialysis operation has been applied to treating polymer-flooding wastewater and received better economic effect. But serious ion-exchange membrane fouling (especially for anion membrane) is the main problem that holds back this technology's further application. The emphasis of this research is to study the effect of polymer-flooding wastewater on anion membrane performance. Oilfield wastewater is a kind of multiphase system that containing solid suspend, liquid suspend, and dissolved salt. A small-scale 5-compartment electrodialysis was developed to study the effect of main fouling substances of polymer-flooding wastewater (solid suspension, crude oil and polymer) on the performance and apparent characteristics of anion membrane from microcosmic (membrane surface resistance, average current, desalination rate, etc.) and macroscopical (scanning electron microscope and atomic force microscope, AFM) views, respectively. The concentration of cations is measured with atom absorbing spectrum (PERKIN-ELMER 703), the concentration of anions is measured with ion chromatogram (DLONEX 4500i) and the sum amount of ionic concentration is TDS. The experimental results show that fractional solid suspension congregated on the surface of, or inside, anion membrane and fouled membrane. Crude oil formed a compact oil film after being absorbed, which affects ions to get through ion-exchange membrane. The polymer may congregate on the surface of anion membrane, and had some influence for permeation of anion membrane. The membrane fouling changes little with time going on.     

Recent advances in reverse osmosis and electrodialysis membrane desalting technology

The potential impact of recent developments in both reverse osmosis and electrodialysis membrane desalting technology are summarized.Particular emphasis is given to the status of advanced technology reverse osmosis membranes with chlorine resistance having single pass seawater desalination capability. Membranes capable of using low operating pressures for brackish water desalting are also reviewed.Results obtained with large prototype reverse osmosis modules and their potential effect on lowering plant capital costs are presented.Possible elimination of acid and use of ultrafiltration as the predominant pretreatment step in seawater desalination plants are also described.Recent developments in the high temperature electrodialysis program for seawater desalting and in the use of newly developed anion membranes for brackish water desalination are reviewed.Finally, the effect of recent budget cut-backs imposed on the office of Water Research and Technology (OWRT) and potential impacts on future membrane desalination R&D activity are discussed.     

Fouling of reverse osmosis membranes by hydrophilic organic matter: implications for water reuse

Effluent organic matter (EfOM) is suspected as a major cause of fouling of reverse osmosis (RO) membranes in advanced wastewater reclamation. Among the main constituents in EfOM, polysaccharides are the most ubiquitous. The influence of solution chemistry and hydrodynamics on RO membrane fouling with alginate — a model for polysaccharides in secondary wastewater effluent — was systematically investigated. Results of fouling runs with alginate demonstrate that RO membrane fouling increases with decreasing pH, increasing ionic strength, and addition of calcium ions. At fixed solution ionic strength and pH, the presence of divalent calcium ions, at concentrations typical of those found in secondary wastewater effluent, had a dramatic effect on membrane fouling. However, for similar concentrations of divalent magnesium ions, fouling was negligible. The severe fouling in the presence of calcium is attributed to the formation of a thick, dense alginate gel layer on the membrane surface via calcium-alginate complexation and crosslinking (bridging) of alginate macromolecules by calcium. In addition to solution chemistry, hydrodynamic operating conditions — initial permeate flux and crossflow velocity — were also shown to influence RO membrane fouling with alginate.     

100t/h反渗透膜化学清洗总结

针对脱盐水装置反渗透膜运行一段时间后出现的因细菌繁殖、结垢造成浓水侧堵塞,产水量下降,进水压力升高等问题,对反渗透膜进行了化学清洗。