USE OF MICROTOX TESTS FOR SCREENING INDUSTRIAL WASTE-WATER TOXICITY

Conventional parameters such as chemical oxygen demand and suspended s olids may not detect toxic compounds present in a variety of industria l wastewaters and treated wastes. Thus, the presence of toxicity in ma ny industrial wastes presents a significant impact on biological waste water treatment, and exerts adverse effects on receiving waters. Becau se of their easy technique and rapid turnaround results, the Microtox tests were used in this study to pinpoint unusual wastewaters, evaluat e the toxicity reduction through activated sludge processes, observe t he impact of excessive chemical addition to meet the transparency stan dard, and measure the impact of waste discharge on one particular rece iving water. It was found that the results of Microtox tests were usef ul for such purposes; i.e., low COD wastes exhibited high Microtox tox icity; some activated sludge processes removed significant toxicity; a nd some effluents from coagulation/oxidation processes showed an incre ased toxicity. The application of the Microtox test to wastewater mana gement is discussed. Copyright (C) 1996 IAWQ.