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CEDI (Continuous Electro Deionization) is a continuous electrochemical process that is applied afterreverse osmosis (RO). A CEDI-system purifies the RO product water to a constant quality (Ultra) Pure water. During this process most of the remaining ions are removed from the product water, including weakly ionized materials, like silicates and CO2.
Operating principle

CEDI-modules consist of product- and reject compartments which are alternately divided by cation selective and anion selective membranes. Both the product and the reject compartments are filled with ion exchange resin.

Under influence of direct current, ions present in the feedwater are transported along the surface of resin beads in the direction of the ion selective membranes. The ions migrate through the membranes into the reject compartments. Where the water in the product compartments becomes nearly ion free, the water splits via direct current in H+ and OH-ions. These in turn regenerate the ion exchange resin continuous. Because only ions can pass the ion selective membranes, a small part of the feedwater is used to expel ions out of the reject compartments.

Features of CEDI-technology

-  No need for regeneration chemicals, which means no chemical waste;
-  Continuous production of pure water and continuous electrical regeneration;
-  More compact than traditional ion exchange plants;
-  Feedwater of concentrate compartments does not have to be electrically     conductive, due to a patented filling of the compartments with ion exchange     resins. Concentrate circulation and/or salt dosage is therefore superfluous;


For more detailed information please have a look at ourreference projects.

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Ion Removal Using CEDI

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