Biogas Production from Opuntia ficus-indica and Dairy Cattle Manure

This study was conducted with the aim to evaluate the addition of different levels of Opuntia ficus-indica cladodes on the cattle manure fermentation for biogas production. Biogas production was measured for 14 days in 1-L batch digesters at 32 degrees C. Manure received from dairy cows with medium milk yield, which previously was tested to start to produce biogas after 15 d of inoculation. The treatment mixes contained: 0, 20, 40, 60, 80 or 100% of sun dried Opuntia ficus-indica (OF) cladodes and the rest of cattle manure (dry matter basis). 48 digesters were used (8 by treatment), every day the material of the collector bags was extracted and was considered biogas if that was flammable. Volume of flammable gas, flame time and burning temperature were recorded daily. During the experimental periods, gas production was different (P<0.001); 0% mix did not produce flammable gas, 20% OF mix produced biogas during all days (970 ml day(-1)); 40% OF treatment produced higher amounts of gas during the days 1-4 (2525 ml day-1) then a reduction in the 5-11 d (380 ml day-1) and no production on 11-14 d; 60% OF mix produced gas on 1-4 d (2400 ml day-1) and no production on 5-14 d; 80% OF produced gas on 1-3 d (1068 ml day-1) and no in the rest of the time 4-14 d; 100% OF no produced gas on the 1-3 d, but produced on the rest of the time 4-14 d (906 ml day-1). Flame time showed similar trend with the volume with adjusted media of 0, 29, 28, 19, 6 and 20 s for 0, 20, 40, 60, 80 or 100% OF mixes. Flame temperature was similar (P=0.58) 680 degrees C when gas was flammable. Opuntia ficus-indica addition enhances the biogas production of bovine manure fermentation and also could be used as sole material for biogas production.