Electrodialysis

Electrodialysis

Electrodialysis (ED) and electro dialysis reversal (EDR) employ specially prepared reverse osmosis  membranes which are semipermeable to ions based on their charge, and they employ electrical current to reduce the ionic content of water. Electrodialysis involves passing water between two plates with opposite electrical charges. The metals in the water are attracted to the plate with the r negative charge while the non-metals are attracted to the plate with the positive charge. Both types of ions can be removed from the plates and discarded. 

Electrodialysis is used on very hard water, with a hardness of more than 500 mg/L as calcium carbonate. 

Recent developments have im proved the efficiency of ED by reversing the polarity of the electrodes periodically. This is called EDR and has reduced the scaling and fouling problems common to ED.

Photo view of  Electrodialyis Plant. 

ED - WATER TREATMENT PLANT