The textile industry is a field which has strong environmental impacts due its high consumption of water and emission of pollutants, specially the dyes. The dyes are organic or synthetic substances which alter the physicochemical characteristics of the water body in which they are released, increasing the toxicity, reducing the oxygen and light, intensifying the color and turbidity, and depleting aquatic life. The reduction of the ecotoxicological effects of the subproducts and the efficiency of treatment are points that still need much improvement. Research has shown that most dyes are resistant to conventional treatments, requiring the use of alternative treatments, as advanced oxidation processes. The aim is to evaluate the efficiency of applying the photo-Fenton process, with sunlight as a polishing treatment, on an effluent of a jeans laundry; and to investigate the degradation of the Drimarem red CL-5B dye and its ecotoxicity, with lettuce seeds before and after treatment. A factorial design was used on two levels, varying time, iron and hydrogen peroxide concentrations factors. After the treatment, there was over 90% mineralization of the dye and significant reduction in the evaluated physicochemical parameters were observed, as color, turbidity and total organic carbon; as well as a great reduction in the toxicity of the effluent.

Keywords: Photo-Fenton Process; Drimaren Red CL-5B; Textile Industry Effluent;