ELECTRODIALYSIS WITH ION EXCHANGE AND BI-POLAR ELECTRODIALYSIS

摘要

In a water treatment system described in this specification, an ED device (which may be an EDR device) is combined with an ion exchange unit and a bipolar electrodialysis (BPED) device. The ion exchange unit, for example a weak acid cation exchange unit, is placed upstream of the ED device and removes divalent cations from the feed water to the ED device. The BPED device receives the salt-concentrated solution from the ED device and produces a regenerating solution. This regenerating solution is used to recharge the ion exchange unit when required. The regenerating solution may be an acidic solution.