PRODUCTION OF BIOGAS FROM WILD SAGE (Lantana camara) CO-DIGESTED WITH COW DUNG

Abstract

Biogas is a clean and renewable form of energy and well substitute for conventional sources of energy especially in the rural sector. In response to the need for addressing the adverse impacts of the increasing trend in biomass energy consumption in Ethiopia, the last three recent decades development of more efficient cooking stove technologies and alternative sources of household energy had been realized. The aim of this study was to determine the optimal mix ratio for biogas production from anaerobic co-digestion of Lantana camara and Cow dung. The experiment was batch operated under mesophilic condition (38ºC) and daily biogas yield from the plant was monitored for 30 days. The parameters studied were total solids (TS), volatile solids (VS), organic carbon, pH and moisture content. The five mixed substrate treatments were 100% CD, 75%:25% CD: LC, 50%:50% CD: LC, 25%:75% CD: LC and 100% LC. The gas production rate was measured on daily basis using water displacement method. Gas production was noticed in all of the substrate types from the first day of digestion up to the 28thh day and became zero at about the 29th & 30th day in all digesters.From the 30 days the maximum yield of biogas were registered at the 3rd day. The experimental data showed the highest gas production in the mix ratio of 25% CD and 75% LC (338.4 ml.) suggesting that this mix ratio is the optimal level to yield the highest biogas production. The total gas produced in all digesters within 30 days for TD1, TD2, TD3, TD4 & TD5 are 163.6, 240.7, 282.0, 338.4 & 204.3 ml. respectively. All measured TS, VS, pH, organic carbon and moisture content values were significantly varied between before and after anaerobic digestion (AD). Overall results indicate that the biogas yield, Volatile solids and Total solids reduction can be significantly enhanced when Lantana camara and Cow dung are co-digested in 25% CD and 75%LC mix ratio.