ELECTROCHEMICAL REMOVAL OF COLOR AND TOXICITY FROM BLEACHED KRAFT EFFLUENTS

A laboratory-scale, flow-through, electrochemical process reduced colo r from mill effluents as much as 90%. Toxicity decreased to a smaller degree. Increasing cell current, decreasing solution pH, and increasin g solution temperature each increased the rate of color removal. Condu ctivity fluid velocity, and electrode spacing had little effect on the rate. The mechanism involved efficient flocculation of colored molecu les with iron hydroxide species. Optimum conditions were 1 A, pH 6, an d 50 degrees C. Capital and operating costs are competitive.