Effect of Ozonation on Biodegradability Characteristics of Surplus Activated Sludge

Abstract

The study investigates the effect of sludge ozonation on solid matter species, disintegration properties, sludge components, and solubilization characteristics under different operating conditions. Ozonation of surplus activated sludge samples taken from the secondary settling tank of a domestic wastewater treatment plant indicates that soluble nitrogen, phosphorus and COD concentrations proliferate as a consequence of extending the ozone feeding time. A steady increase both in soluble nitrogen concentration and ratio of organic phosphorus to soluble phosphorus is observed through ozonation where specific ozone doses range between 4 and 11 mg O3/g SS. Combined treatment of chemical oxidation and aerobic biodegradation to surplus activated sludge is also applied to improve the biodegradability of organic matter by partial chemical oxidative pretreatment with as little specific ozone consumption as possible. The partial oxidation by integrated ozonation is operated as a pre-oxidation step for the subsequent...