Oxidative treatment of simulated dyehouse effluent by UV and near-UV light assisted 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 from 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. To assess the extent of mineralization, decolourization kinetics and the effect of different light sources on treatment efficiency, DOG, optical density at 254 nm and 600 nn wavelength and residual H2O2 concentrations were measured during the course of the advanced oxidation reactions, Comparative evaluation of the obtained results revealed that the decolourization rate increased 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 low doses of the H2O2 oxidant and Fe2+ - ion catalyst within 60 min treatment time. (C)1999 Elsevier Science Ltd. All rights reserved.