Triveni offer Continuous Electrodeionisation unit (CEDI) as a continuous process for producing high purity water using ion exchange membranes, resin and electricity. Direct current (DC) is the driving force for removing ions from the feed stream while continuously regenerating the ion exchange resins. This process produces a consistent, predictable water quality, greater than 99% TDS removal with feed water conductivity of < 40 microsiemens / centimeter.

Ions contained in the feed water migrate to the ion exchange resin that fills the product compartments. Under the influence of DC voltage, these ions are transferred along the resin and through the ion exchange membranes to the reject stream for removal. The resin serves as a highly conductive media through which the ions can travel. The DC voltage also splits water into hydrogen and hydroxyl ions which in turn continuously regenerates the ion exchange resin. Since this process is continuous, the resins never exhaust and constant multi-megaohm water quality can be produced.

Continuous electrodeionization system operation requires that a fraction of the feed be diverted to the concentrate and electrode compartments whereby dissolved ions can be collected and purged from the deionization system. The ratio of product to reject flow is application dependent. Typically, recoveries of 85 to 95% are achieved. Due to these high recoveries the CEDI feed water generally must be pretreated by reverse osmosis.

See next page for Illustrative comparision of CEDI Vs. Conventional Resin Based Systems