Degradation and toxicity reduction of textile effluent by combined photocatalytic and ozonation processes

To minimize the environmental impact of textile effluents, mainly related t o their high coloration and the presence of toxic or carcinogenic reactive dyes, the efficiency of photochemical and ozonation processes, applied in t he form of isolated and combined procedures. were evaluated. The investigat ion was focused on the reduction of total organic carbon content (TOC), col or and acute toxicity (monitoring by inhibition of Escherichia coli respira tion). For a reaction time of 60 min, the anatase TiO2-assisted photocataly tic process produces color and TOC reduction of about 90% and 50%, respecti vely. Meanwhile, the ozonation process gives a decolorization of about 60% but negligible TOC reduction. When the processes were applied in a simultan eous form. the decolorization was almost complete and the TOC reduction was higher than 60%. The three treatments studied yield an acute toxicity redu ction of around 50%. (C) 1999 Elsevier Science Ltd. All rights reserved.