Simultaneous removal of COD and color from dye manufacturing process wastewater using photo-Fenton oxidation process

The removal of COD and color present in dye manufacturing process wastewate r were studied using the photo-Fenton oxidation process. Emphasis of this s tudy was placed on the effects of UV light intensity, ferrous and peroxide dosages, and the pH value on the process performance. Around 76% and 93% re movals of COD and color can be achieved, respectively, under the experiment al conditions of this study. Applying relatively higher UV power was found to accelerate the removals remarkably, and the enhanced effect becomes more and more significant as reaction carries on. The presence of ferrous ions enhanced the removal rate greatly during the initial reaction period, and a fter a certain time point the removal profiles became leveling off due to t he lack of H2O2 residue in the reaction mixture. An excess of H2O2 does not necessarily result in relatively higher removals of COD and color. As for the pH effect, the values of pH = 3 and 4 were found optimum for the remova ls of COD and color, respectively. According to this study, the photo-Fento n process can be considered as a promising technology for the treatment of dye manufacturing process wastewater.