A Review on Utilization of Organic Matters in Activated Sludge

Abstract

Activated sludge process has been applied worldwide in municipal and industrial wastewater treatment practices. Excess sewage sludge, produced in sedimentation after wastewater bio-treatment, is an inevitable by-product of wastewater treatment processes. In any case sludge treatment and disposal should always be considered as an integral part of treatment of wastewater. Currently, the most widely available options in the world are the agriculture utilization, the waste disposal sites, the land reclamation and restoration, the incineration and other novel uses. Extracellular polymeric substances (EPS), as high-molecular weight compounds are secreted by activated sludge microorganisms, which can significantly influence the physicochemical properties and function of activated sludge flocs. Because of the crucial roles of EPS, many researchers have been made to explore their chemical compositions and physicochemical properties. Polysaccharides, humic substances and proteins are usually found to be the major components of EPS. The present paper sought to review past and future trends in sludge handling, focusing mainly at the organic matters.