TWT - Ultrapure ElectroDeionization Plants (EDI)

Where the water quality obtained through the classical deionization systems, like ionic exchange or inverted osmosis, can’t satisfy the needed standards of an industrial process (usually pharmaceuticals or electronics processes) or of an high pressure thermal cycle (steam turbine) the employment of a further treatment is needed.

As an alternative to the traditional mixed beds ionic exchange technology, TWT’s proposal are plants based on electro deionization EDI processes. The process employs compartments cells containing cationic and strong anionic resins, mixed, as to simulate the traditional mixed bed, and separated by cationic and anionic semi permeable membranes. At the extremities of the so obtained compartment two electrodes, connected to a continuous electric power supply, are installed. Once there is electric current in the electrodes, we assist at the migration and the consequent concentration of the ions at the relative electrodes. The same electric current’s passage continuously regenerates the resins with no need of caustic soda or acids. The amount of water containing the concentrated salts, approximately the 5% of the feeding, is discharged and it can be, depending on the circumstances and the necessities, eliminated or sent back before the osmosis plant. The obtained water quality is guaranteed at 16 M ohm/cm (0,06 µS/cm).

• Constant quality of the produced water.
• Minimal electrical expenses compared to the running expanses of other similar processes.
• Operator not exposed to the contact with dangerous chemical products.

TWT also offers traditional technologies like the ionic exchange resins with final mixed bed polishing. The results obtained with this process are similar to what described above.