Biogas production from most agricultural organic wastes by anaerobic digestion in Taiwan

Agricultural organic wastes (AOW) have the potential to provide bioenergy particularly found in biogas by anaerobic digestion (AD). In this study, the biogas production (BP) of AOW was obtained by batch AD with anaerobic digesters (500 mL) at 35 degrees C incubator. The results showed that BP values in terms of volatile solids (VS) from rice husk, rice straw, flower residues, fruit and vegetable residues, wasted oyster shell residue (WOSR), fishery residues, livestock and poultry manures, livestock and poultry slaughter wastes (LPSW), and eight equally mixed wastes (EEMW) were 84.03, 193.36, 153.32, 76.27, 150.48, 63.26, 169.63, 615.74, and 172.83 mL/g VS, respectively. LPSW showed the highest mu(m) of 16.99 mL/g VS-d, the highest BP of 615.74 mL/g VS and the highest bioconversion efficiency of 65.98% compared to the other organic wastes. BP from the most AOW in Taiwan by AD was estimated to be 768,567,753 (743,522,223, excluding WOSR) m(3)/year. The annual BP of 768,567,753 m(3)/year of the eight total major AOW by AD was lower (similar to 20.11%) than 961,989,781 m(3)/year of the EEMW by anaerobic co-digestion. Result also showed that modified Gompertz equation was suitable to describe BP accumulation and BP rate.