电渗析（ED）是一种膜脱盐工艺，最初开发于20世纪50年代。该工艺使用直流电，通过阳离子和阴离子选择膜将盐和其他电离物质去除到浓缩收集流中。膜是以薄片形式浇铸的离子交换树脂。阳离子或阴离子的选择性是由树脂中离子交换位点的正负电荷产生的。在20世纪70年代早期，电渗析逆转（EDR）被开发出来。EDR是对ED过程的机械强化，其中所施加直流电源的极性周期性反转，从而暴露膜表面和流动室以浓缩和脱盐流。 本文讨论了EDR在地表水和废水淡化中的应用，以及该工艺成功的四个基本原因，包括:膜对浊度的耐受性；连续接触氧化消毒剂以防止生物污染的膜耐受性；膜对不可逆污染的抵抗力；此外，如果系统出现物理和化学污染问题，是否存在有效的方法来恢复系统。包括3个参考文献、表格和图表。

Electrodialysis (ED) is a membrane desalination process that was initially developed in the 1950s. The process uses direct current power to remove salts and other ionized species through cation and anion ion selective membranes to a concentrate collecting stream. The membranes are ion exchange resins cast in sheet form. The selectivity for cations or anions is created by the negative or positive charge given to the ion exchange sites in the resin. In the early 1970s, electrodialysis reversal (EDR) was developed. EDR is a mechanical enhancement of the ED process where the polarity of the applied DC power is periodically reversed which exposes the membrane surfaces and flow compartments to concentrate and the desalting stream.This paper discusses the use of EDR to desalt surface and wastewaters and the four basic reasons why this process is successful which include: membrane tolerance to turbidity; membrane tolerance for continuous exposure to oxidizing disinfectants to prevent biological fouling; membrane resistance to irreversible fouling; and, the existence of effective methods to recover systems from physical and chemical fouling problems should they occur. Includes 3 references, tables, figures.