Oxidative treatment of simulated dyehouse effluent by UV and near-UV lightassisted Fenton's reagent

UV/Fenton, near-UV-visible/Fenton, dark Fenton, and H2O2/UV reactions have been used to treat simulated dyehouse effluents representing wastewater fro m the textile dyeing and rinsing process. Experiments were carried out in a lab - scale photochemical reactor using concentrations of 0.5 - 25 mM H2O2 , 0.04 - 0.5 mM Fe2+ - ion and different dilutions of textile wastewater. T o assess the extent of mineralization, decolourization kinetics and the eff ect of different light sources on treatment efficiency, DOG, optical densit y at 254 nm and 600 nn wavelength and residual H2O2 concentrations were mea sured during the course of the advanced oxidation reactions, Comparative ev aluation of the obtained results revealed that the decolourization rate inc reased with applied H2O2 and Fe2+ - ion dose as well as the strength of the synthetic textile wastewater. The best results were obtained by the near - UV/visible/Fenton process with a decolourization rate constant of 1.57 min (-1), a UV254nm reduction of 97 % and a DOC removal of 41 % at relatively l ow doses of the H2O2 oxidant and Fe2+ - ion catalyst within 60 min treatmen t time. (C)1999 Elsevier Science Ltd. All rights reserved.