Sewage Sludge Treatment: An Overview and Its Possibility in Nepal

Abstract

Globally, municipal wastewater treatment produces excessive amount of semisolid residual products, which is also known as sludge, at different stages of its operation. Sludge comprises of organic and inorganic matter, pathogens and heavy metals. Conditioning, thickening, dewatering, thermal drying, aerobic and anaerobic digestion are sludge treatment processes adopted worldwide for its safe disposal. However, Nepal has inadequate wastewater and resulting sludge treatment facilities. The present study evaluates these sludge treatment processes with emphasis on their efficiency to reduce sludge volume. It also analyzes the energy requirement for these processes to identify a suitable solution for Nepal.