Production of biofertilizer from vermicomposting process of municipal sewage sludge

Abstract

This study examines the potential of tiger worms (Eisenia fetida) in vermiculturing Municipal Sewage Sludge (MSS) into beneficial vermicompost or biofertiliser. Tiger worms weighed 1000 g were cultured in plastic bin (45×30×30 cm) containing 25000 g sewage sludge taken from a selected sewage treatment plant in Malaysia. The daily feeding rate of MSS was made to be equal with the weight of worm biomass. Sludge volume reduction due to vermicomposting process was determined daily. Physical parameters such as temperature, moisture content and pH were recorded. Nutrient contents in vermicompost such as Total Nitrogen (TN), Total Phosphorus (TP) and Total Potassium (TK) were determined for day 1, 7, 14 and day 21. Results showed that vermicomposts produced by tiger worms gradually possessing higher nutrient contents as the composting process progressed. Total nitrogen was found to increase from 19.6 to 35.7 mg L-1, total phosphorus from 9.45 to 10.87 mg L-1 and total potassium from 3.44 to 4.80 mg L-1, respectively. In addition conversion of MSS to vermicompost was found to be 93% by weight and worm biomass showed 30% increment from its initial weight within 21 days. Thus, the present study showed vermicomposting of MSS into organic fertiliser is feasible besides providing a safe and practical disposal method for sewage sludge. © 2010 Asian Network for Scientific Information.