The electro-deionisation is a process for continuous demineralisation of permeate from a reverse osmosis unit. An EDI module consists of several chambers that are separated by ion-selective membranes. The chambers are filled with ion exchange resin and placed between two DC voltage electrodes.
Particular advantages of this method are uninterrupted operation without need for chemicals. These units have a very small footprint. The EDI concentrate – concentrated RO permeate – does not require neutralisation; it can be recirculated within the unit or used for other purposes.