Effect of different solid concentration on biogas yield and composition during anaerobic fermentation process

The anaerobic fermentation experiments were carried out on a self-manufactured bench scale anaerobic digester with pig dung as feed material. Under mesophilic digestion condition, effects of different solid concentration of feed on characteristics of biogas production were investigated. Results showed that daily average biogas production rate and total biogas yield were increased with the increases in the solid concentration of feed. The highest daily average biogas production rate of 1114.84 ml l<SUP align="right">−1</SUP> days<SUP align="right">−1</SUP> and total biogas yield of 17,057 ml were obtained at solid concentration of 12%, respectively. However, the highest TS biogas production rate of 174.86 ml g<SUP align="right">−1</SUP>was obtained at solid concentration of 9%. Methane contents at solid concentration of 6, 9 and 12% were 60.8, 68.1 and 68.8%, respectively, after 15 days digestion.