Pilot plant studies on the removal of trihalomethanes by composite reverse osmosis membranes

The effect of single trihalomethane (THM) (CHCl₃) content in various types of water on the performance of two types of reverse osmosis composite membranes (the AFC99 membrane in tubular module B1, PCI, and the FT30 membrane in a spiral-wound element BW3040, FilmTec) have been investigated. The performance of these membranes in RO tests carried out using distilled water, tap water and brackish water (1000–5000 ppm NaCl) with the addition of THM have been evaluated in terms of permeate flux and the rejection of dissolved solids and THM. The FT30 membrane provided THM rejection better than 99.5% during the reverse osmosis treatment of tap water and brackish water. The AFC99 membrane exhibited only 80% retention of THM, obtained for the transmembrane pressures in the range of 10 to 30 bars. It was found that the presence of CHCl₃ slightly affects the transport and separation properties of the composite membranes used.     

反渗透用于工业污水回用运行中问题的分析

由于工业污水的复杂性,反渗透系统在实际运行过程中会出现很多的问题。通过对太钢除盐水系统运行情况的总结,探讨大型反渗透系统运行过程中常见的问题及应对方法。     

二级反渗透工艺系统简介

简述了反渗透原理以及利用机械过滤器、活性炭预处理加二级反渗透的工艺制备纯水的流程，同时介绍了主要设备的工作原理及特点。     

超滤用于海水淡化预处理的研究进展

良好的预处理是保证反渗透(RO)装置长期稳定运行的关键要素之一.与传统预处理技术相比,UF预处理能够有效降低海水的SDI、浊度和TOC等,为RO装置提供优良、稳定的进水,增强RO膜的可靠性.详细评述了近年来国内外采用UF技术作为RO淡化预处理过程的研究和应用进展.此外,对UF膜的污染和控制对策研究进展也作了评述.UF作为膜法海水预处理技术已成为该领域的发展趋势.     

反渗透入水CODMn超标的原因分析及处理

针对宝鸡第二发电公司零排放系统投产阶段反渗透入水CODMn超标的问题，对反渗透系统影响CODMn的因素进行了分析和调整试验，找出了导致CODMn超标的原因；通过采取相应的措施，解决了反渗透系统投产阶段反渗透进水CODMn超标的问题。     

Use of membranes for heavy metal cationic wastewater treatment: flotation and membrane filtration

A new water treatment process—membrane flotation—is presented. The hydrodynamics of air sparging with the use of microporous membranes was studied as well as the membrane flotation efficacy for cationic wastewater treatment. The performance of membrane filtration processes was evaluated. Ways of integration of flotation and membrane filtration in cationic wastewater treatment practice are discussed.     

短程反渗透海水淡化工艺在海岛中的应用

根据海岛海水淡化的应用环境,分析了海岛对集约型海水淡化工艺的需求,提出了短程反渗透海水淡化工艺,从工艺原理、技术特点及在海岛中的应用优势进行了阐述,并通过300m3/d的工程案例从反渗透产水水质、压差能量回收装置性能和系统能耗等方面考察了短程反渗透海水淡化工艺的运行效果,处理效果验证了该工艺的可行性和技术优势。     

The fate of Transparent Exopolymer Particles (TEP) in integrated membrane systems: Removal through pre-treatment processes and deposition on reverse osmosis membranes

The abundance of Transparent Exopolymer Particles (TEP) in surface waters has been unnoticed for many years until recently as a potential foulant in reverse osmosis systems. Recent studies indicate that TEP may cause organic and biological fouling and may enhance particulate/colloidal fouling in reverse osmosis membranes. The presence of TEP was measured in the raw water, the pre-treatment processes and reverse osmosis (RO) systems of 6 integrated membrane installations. A spectrophotometric method was used to measure TEP in the particulate size range (>0.40 μm) and was extended to measure TEP in the colloidal size range (0.05–0.40 μm). Ultrafiltration pre-treatment applied in 4 plants, totally removed particulate TEP while microfiltration systems (2 plants) and coagulation/sedimentation/rapid sand filtration systems (3 plants) partially removed this fraction. None of the pre-treatment systems investigated totally removed colloidal TEP. Biopolymer analysis using LC–OCD showed consistency between colloidal TEP and polysaccharide removal by UF pre-treatment and further verified the presence of TEP in the RO feedwater. TEP deposition in the RO system was determined after measuring total TEP concentrations in the RO feed and concentrate. The TEP deposition factors and specific deposition rates indicate that TEP accumulation had occurred in all plants investigated. This observation was verified by an autopsy of RO modules from two RO plants. Further improvement and verification of the (modified) TEP method, in particular the calibration, is necessary so that it can be employed to investigate the role of TEP in the fouling of RO systems.     

RO membrane solute rejection behavior at the initial stage ofcolloidal fouling

This study investigated the rejection of salt and inert organic compounds by reverse osmosis membranes during the initial stage of colloidal fouling. Results of laboratory-scale experiments showed that colloidal fouling caused a marked decrease in flux, salt rejection and rejection of organics with molecular weight (MW) smaller than about 100 g/mol. Removal of neutrally charged organics was mainly by size or steric exclusion. Rejection of xylose, which has MW >100 g/mol, was not affected much by colloidal fouling. The decrease in salt and low MW organic rejections during the initial stage of colloidal fouling was attributed to cake-enhanced concentration polarization, whereby the colloidal cake layer hindered back diffusion of solutes from the membrane surface to the bulk solution, resulting in higher solute concentration gradient across the membrane. At higher channel wall shear rate, the rates of colloidal deposition, flux decline, decrease in salt rejection, and decrease in low MW organic rejection were lower.     

高取代度氰乙基纤维素膜及其共混膜的研究——Ⅱ.高取代度氰乙基纤维素反渗透膜

本文对高取代度氰乙基纤维素(HCEC)的制膜工艺进行了初步研究,并考察了膜的化学稳定性和渗透选择性。结果表明,HCEC膜除有优良的耐微生物分解性能外,在耐酸、碱水解和耐活性氯氧化性能上也远胜于醋酸纤维素(CA)膜。在对溶质的渗透选择性能方面,HCEC膜对荷负电溶质有较高的截留性能,并表现出类似于荷电型阳离子反渗透膜的某些特征。