• Dutco Tennant LLC, PO Box 233, Dubai, U.A.E.
Electrodeionization Waste Water Treatment Process Plant

Description

Increased recognition of the effect of ultrapure water quality on system component life has resulted in demand for membrane systems which can render an even higher purity of water than mixed-bed deionization systems alone can achieve (e.g. lower TOC, particles, etc.). Such high levels of demineralization can be obtained using electrode ionization (EDI). EDI combines ion exchange resins, ion-exchange membranes, and a direct (DC) electric field. Basically, EDI is an electro dialysis (ED) process modified by the addition of ion-exchange resin. When EDI is used for the production of high purity water, the ion-exchange resin beads enhance mass transfer, facilitate water splitting, and reduce stack resistance.

The ion exchange resin exchanges ions with the incoming feed stream. The DC electrical field splits water into hydrogen and hydroxyl ions, which, in turn, continuously regenerate the ion-exchange resins. The exchanged ions are transferred through the membranes to the brine stream and flushed from the system.1,2 Compared to conventional ion exchange, EDI has the advantage of being a continuous process with constant stable product quality, which is able to produce ultra-high purity water without the need for acid or caustic regeneration.

Electrode ionization (EDI) is an electrically-driven water treatment technology that uses electricity, ion exchange and resin to remove ionized species from water. The combination of ion-exchange resins and ion-exchange membranes, which are used to move ionic impurities into a waste or concentrate water stream leaving purified product water.

As impurities leave via the concentrate water system, their build-up does not exhaust the resin and therefore prolongs resin lifespan. A single EDI unit may operate for many years before a replacement is required. Typically product water resistivity of >15 MΩ.cm is consistently achieved using this process. This technology can be used as an alternative to single-use purification cartridges.

Its development and use in water purification overcame some of the limitations of ion exchange resin beds, particularly the release of ions as the beds exhaust.

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