Electro-Deionization
ISS offers electro-deionization for producing Ultrapure water. The EDI unit uses ion-exchange membranes and resins with electric current to remove dissolved salts from water. EDI does not require chemical regeneration, but it is limited to applications where the dissolved salt is small compared to the salt concentration contained in natural water supplies. The typical EDI application treats water that has been partially demineralized by reverse osmosis. Ultrapure water, in excess of 16 Mohm/cm and which has been depleted of ions, flows out of the chamber as a result of this process.