Production of biogas using different ratios of goat and dog dung mixed wth corn cob and rice chaff

Investigations were conducted to evaluate the viability of corncob and rice chaff co-digested with goat and dog dungs in the production of biogas. The study was carried out at mesophillic condition in six mini laboratory digester fabricated using guage 16 metal sheets with 80L capacity for five weeks retention time. Five different ratios of goat and dog dungs were blended with the feedstock. The ratio of the blends is as follows; sample A: Corn cob, Rice chaff, Goat dungs (25%), Dog dung (25%), sample B: Corn cob, Rice chaff, Goat dungs (50%), Dog dung (50%),sample C: Corn cob, Rice chaff, Goat dungs (75%), Dog dung (75%), sample D: Corn cob, Rice chaff, Goat dungs (25%), Dog dung (75%), sample E: Corn cob, Rice chaff, Goat dungs (75%), Dog dung (25%), sample F: (negative control) Corn cob, Rice chaff only. The gas yield was analysed using the chromatography system which is composed of the gas chromatography equipment and a recorder for plotting chromatographs. The equipment model is Hp6890 with HP ChemStation and Rev. A09.01 (1206) software. The result showed thatsampleE is the richest of all the samples in terms of the proximate and physiochemical compositions. The biogas constituents obtained showed that sample A produced 56 % CH4, 0.11 % NH3, 0.16 % CO, 0.17 % H2S, 42.64 % CO2, Sample B produced 60.80 % CH4, 0.86 % NH3, 0.71 % CO, 0.55 % H2S and 0.52 % CO2, Sample C produced  61.35 % CH4, 0.41 % NH3, 0.41 % CO, 0.68 % H2S, 37.12 % CO2, Sample D contains 50.70 % CH4, 0.24 % NH3, 0.79 % CO, 1.05 % H2S, and 47.13 % CO2. Sample E contains 63.54 % CH4, 0.93 % NH3, 0.84 % CO, 0.54 % H2S, 34.12 % CO2. The control sample collected from a domestic cooking gas cylinder contained 56.12 % CH2, 0.14 % NH3, 0.22 % CO, 0.23 % H2S and 43.20 % CO2. Over the 5 weeks period of digestion; the yield for the samples were 40L, 47L, 42L, 38L and  65L respectively for samples A,B, C, D and E respectively while sample F produced no gas throughout the digestion period. The value recorded for sample E represented the highest value obtained among the samples. Thesubstrates by these results were considered a suitable substitute for biogas production.