The DC voltage applied makes the ions contained in the EDI feed water migrate through the electric field to the corresponding electrode. Cations are attracted by the cathode and anions by the anode. Due to the arrangement of the ion-selective membranes, the ions are collected in the channels between the cambers and carried out of the module by a partial stream, the EDI concentrate flow.
Particular advantages of this method are uninterrupted operation without need for chemicals. The 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.
The diluate, in general with a conductivity of < 0.1 µS/cm, meets highest standards.