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

Abstract

This study was designed to evaluate (1) the removal of the non-biodegradable organics and color by Fenton's oxidation (2) the feasibility of Fenton's 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, H2O2 dosage, molar ratio of Fe2+/H2O2 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, BOD5COD ratio was not changed much after Fenton's oxidation, but in the case of the Red wastewater, BOD5COD ratio was increased from 0.04 to 0.36. Therefore Fenton's oxidation process is a very effective means for a pretreatment or tertiary treatment in the Pigment wastewater.