ABSTRACT
When the digestion process is not stabilized with chemicals or buffering material in the slurry, biogas from cassava peels and cow dung has low methane concentrations. Two 235L digesters were utilized, digester A had 30 kg of cassava peel, 30 kg of cow dung, and 120 kg of water in the ratios of 1:1:4 and digester B had 30 kg of cassava peel, 30 kg of cow dung, 120 kg of water, and 2.4 kg of oil palm fuel ash, in the ratio of 1:1:4:0.08. A digester named Digester A generated 1070.3 liters of biogas with a maximum methane content of 33.6%. Digester B, on the other hand, generated 1178.1 liters of biogas with a maximum methane content of 60.1%. This result showed that adding oil palm fuel ash as a buffer for pH stabilization caused a larger amount of produced biogas and methane content.
