ACUTE RESIDUAL TOXICITY OF SEVERAL WASTEWATER DISINFECTANTS TO AQUATIC LIFE¹

Abstract

ABSTRACT: This study was conducted to determine the comparative acute toxicity of chlorine, bromine chloride and ozone in wastewater, and to determine any acute toxicity associated with chlorinated wastewater which had been dechlorinated with sulfur dioxide. Toxicity tests were conducted with several species of cyprinids, salmonids and centrarchids, and the freshwater macroinvertebrate, Daphnia magna . Chlorinated effluent exhibited the greatest potential for residual toxicity of any disinfected stream tested. The reduced residual toxicity of chlorobrominated or ozonated effluent was largely the result of the more rapid dissipation of these disinfectants in wastewater. The acute residual toxicity of chlorinated effluent was eliminated by dechlorination with sulfur dioxide.