ELECTRODIALYSIS OF EFFLUENTS FROh4 TREATMENT OF METALLIC SURFACES

The use of ion-exchange membranes to concentrate sea water and to produce fresh water from brine has been investigated for about one quarter-century and has now achieved the practical stage. The entire domestic supply of table salt in Japan is produced by electrodialysis. Many positive results on production of fresh water from brine have been attained in the U.S., the Mediterranean regions and in the Middle East. Recently, plants for production of fresh water for use in boilers have been constructed in Japan. Electrodialysis has been practically applied for purification by means of desalination during various processes in the medical, food and chemical industries. Recently, electrodialysis has been applied widely in the field of effluent treatment. It has been utilized for purification of effluents from the treatment of metallic surfaces, including effluents from galvanization . In addition, technical development is .continXing with a view to applications in recycling factory eMuents and drainage.