Colour and COD removal from pulp and paper mill effluent by q Fenton's oxidation.

Colour and COD removal studies of pulp and paper mill effluent were carried out by Fenton's oxidation. Fenton's oxidation process was employed in four distinct stages interrelated to each other. In the first stage, FeSO4 concentration, pH and temperature were kept constant to determine H2O2 dose for maximum color and COD removal. In the second stage, dose of H2O2 obtained from first stage and same oxidation conditions were applied to determine the optimum FeSO4 concentration. Optimum pH, temperature and contact time were investigated in third and fourth stages considering the results of optimum doses of first and second stage. Maximum color up to 98% and COD removal up to 62% were obtained for Fenton reagents of 600 mg/L of H2O2 and 100 mg/L of Fe2+ dose at pH 3.0 for 300 min of contact period between reagents and effluent.