EN
Toxicity of four types of industrial wastewater, treated by Fenton’s reagent, was analyzed. Toxicity was measured using bioluminescent bacteria Vibrio fischeri NRRL B-11177. Application of Fenton’s reagent was a efficient method for treatment of this wastewater. Nevertheless, high efficiency of organic components degradation was not always followed by reduction of toxicity to a very low level. In all cases, in order to achieve total reduction of toxicity, it was necessary to increase both the H2 O2 dose and reaction time. It was concluded that optimization of Fenton’s reaction should be performed assuming toxicity changes in the examined wastewater. Reduction in toxicity should be a critical measure of the success of this method. Such an approach should be general practice in relation to all hazardous industrial wastewater.