高盐废水制取高纯水工艺研究

THE PROCESS STUDY ON THE HIGH-PURITY WATER PREPARED BY HIGH SALINITY WASTEWATER

基于高盐废水制取高纯水，对2级反渗透（RO）＋电去离子（EDI）工艺和膜蒸馏（MD）＋EDI工艺进行了试验研究。结果表明，当原水电导率为3310μS／cm时，2级RO的产水电导率为6．5～7-3μS／cm，总除盐率99．78％，MD产水电导率2．6～3．7μS／cm，除盐率99．89％，都可满足EDI进水水质要求，后续EDI产水水质相近，电导率稳定在0．077～0．083μS／cm。2级RO＋EDI工艺技术成熟，能耗较低，但对原水含盐量适应性差，回收率较低（小于60％）；MD＋EDI工艺对原水含盐量适应性强，回收率高（大于90％），但膜通量较低，还处于开发阶段。综合考虑，MD＋EDI工艺更具优越性，进一步完善膜蒸馏技术，应用前景广阔。

Based on high-purity water prepared by high salinity wastewater, two processes including two set of reverse osmosis＋electricdeionization （RO- RO-EDI） and membrane distillation＋eleetriedeionization （MD-EDI） had been studied in this paper. The results indicated that： the electric conductivity of raw water was 3 310 μS/cm. The effluent of RO-RO was 6.5-7.3 μS/cm and the salt elimination was 99.78%, while the conductivity of effluent Of MD is 2.6-3.7 μS/em and salt rejection was 99.89%. Both of the effluent quality couldmeettherequirement of the influentwaterquality of EDI andthe electro conductivity of their effluent stayed 0.077-0.083 μS/cm, which are close. The technique of RO-RO-EDI had been mature with lower energy expenditure, however, it is affected by the salinity of raw water and the rate of recovery is low （〈60%）. Compared with RO-RO-EDI, the salinity of raw water had later influence on the process of MD-EDI, which obtained high recover （〉90%）, but the membrane flux is lower which requires more research. In addition, with the development of membrane distillation, the technique of MD-EDI was pointed out as better and promising.