Generation of biogas from coffee-pulp and cow-dung co-digestion: Infrared studies of postcombustion emissions

Batch digester with coffee pulp/cow dung produced high amounts of methane for 8 months. The FTIR gas spectroscopy analysis revealed the presence of over 70 chemical compounds in biogas generated after 4 months of coffee pulp and cow dung mixture co-digestion, several being hazardous to environment and human and animal health (e.g. isocyanic acid, bromomethane). Biogas produced was burned in a laboratory combustor. The FTIR gas spectroscopy analysis showed that combustion emissions contained: CH4, C3H8, CO, SO2, HI, and probably Br2 which are strongly harmful to human and animal health.