纳滤、反渗透工艺深度处理饮用水研究

利用纳滤和反渗透膜深度处理工艺进行长江原水水质净化中试研究,工艺流程为长江原水→混凝沉淀→沙滤→颗粒活性炭→纳滤/反渗透,比较纳滤、反渗透膜工艺对污染物特别是微量有机物苯系物、三氯乙烯及消毒副产物等的去除效果。结果表明膜工艺预处理能够有效地去除原水的浊度和部分污染物,有利于纳滤、反渗透的稳定运行。纳滤膜工艺的最佳操作压力是0.4 MPa,此压力下产水量为250 L/h,回收率为24%,SO₄^2-,Cl^-,NO₃^-和总硬度的去除率分别为91.7%,85.4%,85.2%,89.3%;采用浓缩水回流能兼顾较高的回收率和良好的去除率。2种膜工艺对苯系物与三氯乙烯的去除率均在95.7%以上;对消毒副产物也有较好的控制效果,其中大部分的削减率在63.7%以上。与反渗透膜工艺比较,纳滤膜工艺具有较低的生产成本。纳滤膜工艺净化出水中可部分保留对人体有益的矿物质,使得净化后的出水成为优质健康饮用水。

Advanced Treatment of Drinking Water with NF and RO Technology

After having been pretreated in turn with coagulation-sedimentation, sand filter and granular activated carbon (GAC), the water of Yangtse River was treated with nanofiltration(NF) and reverse osmosis(RO), respectively. The results indicate that the pretreatments are very important for later treatment reliability since they can remove most turbidity and some pollutants. Under the optimum pressure 0.4 MPa of NF which has been determined in pilot study, the water production quantity and the recovery rate are 250 L/h and 24%, respectively, the removal ratio of SO₄^2-, Cl^-, NO₃^- and total hardness is 91.7%, 85.4%, 85.2% and 89.3%, respectively. Concentrated water reflux can achieve both high recovery rate and removal rate. Additionally, both RO and NF can remove 95.7% of organic contaminants (benzene, trichloroethylene, ethylbenzene, m-xylene, chlorobenzene, nitrobenzene) and also can greatly control disinfection by-products (DBPs) with most elimination rate over 63.7%. Compared with RO, the operation cost of NF is low, and the effluent of NF can be used as drinking water as it contains favorable mineral substances.