Decolorization of Secondary Effluent from Piggery Wastewater by Fenton Reaction Using Iron Powder

A Fenton reaction using 150-um iron powder for treating activated sludge from livestock-raising wastewater resulted in significant decreases in chromaticity and chemical oxygen demand. The optimum weight ratio of H2O2/Fe(0) was 0.3, and the optimum initial pH and the optimum reaction time were 3.5 and 30 mins. Under these optimum conditions, the removal ratios of chemical oxygen demand and the chromaticity of the supernatant after polymer coagulant addition and precipitation of the sludge in a continuous miniplant experiment were 86% and 84%, respectively.