含盐废水电渗析膜分离处理工艺研究

Study on electrodialysis membrane separation technology of salinity wastewater

在水资源日益紧张、含盐废水排放量日益增多的大趋势下,寻求经济有效的含盐废水处理技术已成为重要的研究课题。以厦门某食品企业水产品加工腌泡环节含盐废水为研究对象。含盐废水经氨水沉淀、离子交换树脂软化处理,废水中钙镁离子被有效脱除,出水钙镁质量浓度已经降为10.4 mg·L-1,达到软水水质标准。软化后的废水经4‰聚丙烯酰胺(PAM)絮凝并通过活性炭吸附,污染密度指数值(SDI)降低至0.41,完全达到膜分离装置进水水质的要求。预处理液再经电渗析膜进一步浓缩分离后,氯化钠质量浓度可由7 351 mg·L-1提升到78 156 mg·L-1,对盐分浓缩了10倍以上,达到废水和盐分的处理回收利用。本处理工艺流程简洁,药耗少、能耗低,比较适合小规模含盐废水的综合处理。

Many kinds of industrial and agricultural wastewater contain highly concentrated salt. In developing countries, pollution measures frequently need to be based on lower-cost technologies. In this paper, we focused on electrodialysis membrane separation technology of salinity wastewater. Firstly, Salinity wastewater was softened by ammonia precipitation, ion exchange, and calcium and magnesium ions in the wastewater was effectively removed. The calcium and magnesium content has been reduced to 10.4 mg·L-1, meet softener water quality standards. Secondly, the silt density index （SDI） of wastewater was decreased to 0.41 by polyacrylamide （PAM） flocculation and activated carbon adsorption. At last, the salinity wastewater was further treated by electrodialysis membrane separation unit, and the concentration of sodium chloride can be condensed from 7351 mg·L-1 to 78 156 mg·L-1. This method has wide applicable range, high purifying efficiency, low cost and simple technological process.