%D 2002 %0 ARTICLE %T Ozonation of textile wastewater : physicochemical and phytotoxic aspects . %J %V 23 ( 5 ) %P 537-45 %A Radetski CM %A Rosa SM %A Rosa EV %A De Souza %A Sierra MM %A Simonatto EL %M pub12090258 %X The purpose of this work was to evaluate the performance of ozonation as a technique to treat textile effluents . This performance evaluation was made using physico-chemical parameters and phytotoxic endpoints ( ie biomass growth enzyme activities - catalase and peroxidase ) . After ozonation , the color absorbance ( 523 nm ) was reduced by 80 . 9% and the pH decreased from 10 . 9 to approximately 7 . 5 while COD reduction reached nearly 87% . Phytotoxicity tests carried out in solution with three plant species ( ie soybean , rice and wheat ) allowed us to compare toxicity data of both , raw and ozonated effluents . The biomass ( fresh weight ) of the 3 plant species clearly decreases as a function of the increase in raw effluent concentration with LOEC values of 100% for rice and wheat , and 50% for soybean . Activities of catalase and peroxidase in the 3 plant species exposed to the raw textile effluent were significantly different from plant controls . The LOEC values for catalase were 6 . 2% ( in wheat and soybean plants ) , and 25% ( in rice plants ) , while for peroxidase the LOEC values were 6 . 2% ( in rice plants ) , 25% ( in soybean plants ) , and 50% ( in wheat plants ) . Reduction in the phytotoxicity of textile effluent samples after ozonation is likely due to the elimination of the toxic organic fraction oxidized during this process . Regarding endpoint sensitivity , our results showed that biomass endpoint was less sensitive than biochemical endpoint . In conclusion , ozonation was relatively effective in reducing physico-chemical parameters and phytotoxic effects of textile effluents . Plant enzyme assays used in this study proved to be a sensitive tool in order to determine the toxicity of industrial effluents and may be used to evaluate efficiency of established ( or emergent ) wastewater treatment technology .