Toxicity-based criteria for the evaluation of textile wastewater treatmentefficiency

Brazilian textile mills import wastewater treatment technologies, performan ces of which are generally evaluated only on a physicochernical basis. Thus , a battery of bioassays was used to evaluate the performance of an ozonati on system to treat textile effluents. Comparative toxicological profiles fo r bacteria (Vibrio fischeri), algae (Scenedesmus subspicatus), daphnia (Dap hnia magna), fish (Poecilia reticulata), and plants (soybean-Glycine max, r ice-Oryza sativa, and wheat-Triticum aestivum), as well as genotoxic effect s (Vicia faba micronucleus assay), are presented for both raw and ozonated textile effluents. The relative sensitivity of bioassays (or end points) to textile effluents found in this study in decreasing order was plant enzyme s > bacteria > algae daphnids approximate to plant biomass approximate to g ermination rate > fish. No significant genotoxic effect was found. We have concluded that ozonation was relatively effective in reducing toxicity of t extile effluents. Bioassays used in this study proved to be sensitive and r eliable tools for determining the toxicity of industrial effluents, and thu s they can be used to evaluate emerging technology efficiency.