ELECTROCHEMICAL REMOVAL OF CHROMATES AND OTHER METALS.

Operating data using the electrochemical method of chromate removal for treatment of cooling tower blowdown water has shown that chrome levels consistently under 0. 05 ppm. can be achieved with no pH adjustment of the incoming water provided that it is in the range of approximately 6 to 9 on the pH scale. Operating costs, exclusive of labor, are generally in the range of 5 to 10 cent /1,000 gal. depending upon the chromate concentration. The labor amounts to less than one-half man-hr. /day, used mainly for the acid wash procedure. Operating experience confirms the theory of the process and initial design problems were solved permitting continuous operating periods generally in excess of one month between electrode changes. The feasibility of removing other heavy metals electrochemically as well as as arsenates and other compounds is demonstrated.