Welspring Technology

The EDI module consists of a set of chambers filled with ion exchange resins and separated by ion-exchange membranes. Water enters the module, where an applied electrical field at right-angles to the flow forces ions to move through the resins and across the membranes. The basic structure of an EDI stack is similar to that of a deionization chamber. An ion exchange resin is packed between a cationic exchange membrane and an anionic exchange membrane in the chamber. Only ions can pass through the membrane; water cannot.

The use of electrodeionization eliminates the need to store and handle the hazardous chemicals used in mixed bed resin regeneration. Furthermore, because electricity is the only consumable used by EDI, this method of permeate polishing does not generate a hazardous waste stream.