Removal of refractory organics and color in pigment wastewater with Fenton oxidation

This study was designed to evaluate (1) the removal of the non-biodegradable organics and color by Fenton9s oxidation (2) the feasibility of Fenton9s oxidation as a pretreatment or tertiary treatment following the activated sludge process in the pigment wastewater. The study was divided into two parts. The first part consisted of investigations on raw Yellow wastewater and Red wastewater, the second part was carried out on the final effluent from the existing extended aeration treatment plant. The batch test was conducted to determine the optimum conditions for plant operation such as pH, H 2 O 2 dosage, molar ratio of Fe 2+ /H 2 O 2 and contact time. It was found that the removal efficiencies of COD were 54.2%, 52.6% and 58.9%, the removal efficiencies of the color were 91.2%, 18.1% and 45.7%, for Red, Yellow Wastewater and Final Effluent, respectively. In the Yellow wastewater, BOD 5 COD ratio was not changed much after Fenton9s oxidation, but in the case of the Red wastewater, BOD 5 COD ratio was increased from 0.04 to 0.36. Therefore Fenton9s oxidation process is a very effective means for a pretreatment or tertiary treatment in the Pigment wastewater.