ELIMINATION OF NITRATE FROM DRINKING-WATER BY ELECTROCHEMICAL MEMBRANE PROCESSES

The performance of three membrane processes (Donnan dialysis, electrod ialysis, electrodeionization) using an ADS-Morgane anion-exchange memb rane, was compared to remove nitrate from drinking water. The influenc e of concentration, current density and flow rate was studied with a 3 .10(-3) M nitrate solution to determine the best experimental conditio ns. Then the membrane processes were applied for the treatment of Mont pellier drinking water where the nitrate concentration was increased u p to a concentration of 80-100 ppm. In all cases the results showed ex traction ratios higher than 80%. With the electrodialysis and electrod eionization techniques, the extraction rate of nitrate was faster than with Donnan dialysis, and a deionized water of high purity was obtain ed. A nitrate elimination ratio of 99% has been reached with electrode ionization.