Disintegration of excess activated sludge by hydrogen peroxide oxidation

Abstract

As the result of a conventional wastewater treatment such as activated sludge process, an excess sludge is produced and must be disposed of safely. Recently, increased attention has been given to a minimization of waste sludge in a wastewater treatment process. In this study, hydrogen peroxide oxidation was applied for an excess activated sludge reduction and an alkaline pretreatment method was used to enhance the efficiency of hydrogen peroxide oxidation of sludge. Sludge particle disintegration by hydrogen peroxide oxidation was confirmed through the evaluations of total solid concentration and particle size distribution. The solubility (SCOD/TCOD) of sludge was increased, while the viscosity was decreased with hydrogen peroxide oxidation and alkaline hydrolysis. The settleability of sludge was improved. When alkaline hydrolysis was applied as a pretreatment for hydrogen peroxide oxidation, the sludge particle disintegration, viscosity decrease, and settleability improvement were accelerated. From the results of this experiment, it can be concluded that hydrogen peroxide oxidation combined with alkaline pretreatment was useful for an excess sludge reduction.