Removal of hardness ions from tap water using electromembrane processes

Performances of electromembrane systems were investigated for removal of the hardness materials in a tap water. Six cells of ED, EDR, and EDIR systems with an electrode area of 12.5cm x 8.0 cm were operated. The results showed scaling formation due to water dissociation on the surface of cation exchange membrane, but EDR and EDIR enabled to avoid the scaling problem. EDIR operation lowered the resistance and power consumption compared to EDR due to the conductance of ion exchange resins. This study demonstrated the feasibility of EDR and EDIR processes for water softening.