微滤-纳滤组合工艺在饮用水深度处理中的大型工程应用

张家港第三水厂供水规模为20万m3/d，日常采用混凝+沉淀+过滤+氯消毒的常规饮用水处理工艺。基于纳滤膜对于中小分子有机物与钙、镁、硫酸根等盐离子的高效截留能力，该项目创新性地在国内首次采用现状常规工艺+压力罐式微滤+纳滤的净水工艺，对张家港第三饮用水厂深度处理大型工程（设计产水规模为10万t/d）进行升级改造设计。经改造后，预计纳滤系统对于COD以及TOC的去除率可达到90%以上，消毒副产物的去除率可达到70%~80%，色素类物质的去除率可达到70%以上，臭味物质的去除率为50%~70%，整体脱盐率为30%~40%；纳滤系统回收率整体可达到90%。预计压力罐式微滤系统和纳滤系统的能耗分别为0.003，0.197 kW·h/t；在实现高品质供水的同时，可提高水厂应对突发污染风险的能力。

A LARGE-SCALE ENGINEERING APPLICATION OF MICROFILTRATION-NANOFILTRATION COMBINED TECHNOLOGY IN DRINKING WATER ADVANCED TREATMENT

The water supply scale of the Zhangjiagang Third Water Plant was 200000 m3/d, and its drinking water treatment process is sequentially combined by coagulation, sedimentation, filtration and chlorination disinfection. Based on the remarkable interception ability of nanofiltration membrane for monomolecular organic matters, micromolecular organic matters and saline ions including calcium ion, magnesium ion, sulfate ion, etc, a new water purification process combined by conventional technology, pressed-pot microfiltration and nanofiltrition was creatively applied in the large-scale engineering project of drinking water advanced treatment for the Zhangjiagang Third Water Plant, for the first time in China. The designed water production capacity of this project was 100000 t/d, and the project was aimed at upgrading the existing drinking water treatment technology. After the reformation, the nanofiltration system was predicted to perform over 90% removal rate for COD and TOC, 70%~80% removal rate for disinfection by-products, over 70% removal rate for pigments, 50%~70% removal rate for odorous substances, and 30%~40% rejection rate for salt. The recovery rate of the nanofiltration system was able to reach 90%, while the predicted energy consumption of pressed-pot microfiltration system and nanofiltration system was respectively 0.003, 0.197 kW·h/t, respectively. After accomplishing the project, Zhangjiagang Third Water Treatment Plant will be capable of supplying drinking water with higher quality, and possess higher resistance to water contamination emergencies.