ELECTRICALLY REGENERATIVE PURE WATER PRODUCING METHOD AND DEVICE THEREFOR

PROBLEM TO BE SOLVED: To stably operate a pure water producing device without deteriorating the desalted water quality with less power at the time of impressing a voltage on the cathode and anode to produce pure water by adding an electrolyte soln. to the water to be supplied to the cathode compartment, anode compartment and concentration compartment and treated. SOLUTION: The water to be treated is supplied from an inlet pipe 121, and the treated water (deionized water) is discharged from an outlet pipe 122. Meanwhile, the water to be treated is supplied to the concentration compartments 91, 92,... from an inlet pipe 131, an electrolyte soln. is added from an inlet pipe 141, and concd. water is discharged from an outlet pipe 132. A DC current is applied on the anode plate 2 and cathode plate 4 while circulating the water to be treated and electrolyte soln., hence the impurity ion in the water is collected and removed by the anion- exchange group and cation-exchange group possessed by an ion-exchanger packing 101 in desalting chambers 81 and 82 to produce pure water, the collected impurity ion is electrodialyzed by the anion and cation-exchange membranes in the desalting chambers 81, 82,..., transferred to the concentration chambers 91, 92,..., concentrated and,discharged from the outlet pipe 132 as concd. water.