Removal of nitrates and salts
Selective Electrodialysis (SED) technology is a membrane-mediated process during which ions are transported through semi-permeable membranes under the influence of electrical potential. The SED membranes are selective to nitrate ions, thus separating nitrates from the water flow and concentrating it in separate cells. The SED operates as a membrane stack where cation-exchange and anion-exchange membranes are arranged alternately between electrode cells trapping the nitrate ions in the concentrate effluent.
SED is a highly effective technology which complies with EPA guidelines and enjoys high regulatory acceptance in Israel. It is a small footprint system, with an approximately 95% recovery rate, negligible chemical use (only for treating the concentrate), and minimal waste disposal issues.
Among SED's advantages are:
- Low O&M costs derived from:
- Low energy consumption
- Infrequent membrane replacement (every 7 to 10 years)
- Brine disposal to sewage acceptable owing to low concentrate of salts
- No pre-treatment for water
- No harmful waste by-products
- No chemicals/salts added to the water
- Presence of sulfates in the water does not affect efficiency
- No chlorides added to product water