Comparative assessment of anaerobic digestion of municipal solid waste at mesophilic and thermophilic temperatures

Abstract

Anaerobic digestion is an environmentally sound treatment option for the organic fraction of municipal solid waste (OFMSW) and simultaneously producing methane gas which is a source of renewable energy. The COD reduction of the substrate was 72% for the mesophilic condition and 72.3% for the thermophilic condition. 1200 cm³ of methane was produced in the mesophilic condition and 1260 cm³ in the thermophilic condition. The methane content, by volume, in the biogas was found to be 60% and 63% in the mesophilic and thermophilic condition respectively. It was also found that 0.723 cm³ of methane per unit weight of substrate was produced at the mesophilic condition and 0.760 cm³ of methane per unit weight of substrate at the thermophilic condition. The gas production rate for mesophilic and thermophilic condition were 0.0214 m³ (m³d)−1 and 0.046 m³ (m³d)−1 respectively and the methane yield was more or less the same in both cases. The methane yield in mesophilic condition was 0.0614 m³/kg COD and that at thermophilic condition was 0.0612 m³/kg COD.