Biogas Generation from Co-digestion of Four Substrates; Water Hyacinth, Cassava Peels, Poultry Droppings and Cow Dung

Abstract

Generation of biogas by a combination of four substrates of water hyacinth (Eichhornia crassipes), cassava (Manihot esculentum) peels, poultry droppings and cow dung was investigated using anaerobic digester and gasometric chamber to determine the level of production. Total viable bacterial counts in the combination were 7.86 X107, 5.45 X105 cfuml-1 before and after digestion respectively while fungal counts were 2.45 x102, 3.35 X104 cfuml-1 before and after digestion respectively. The combination of the four substrates, yielded biogas of 815 mls, 875 ml and 1340 mls from respective weights of 1 kg, 2 kg and 3 kg within 15 days without starter culture while with starter culture biogas yield within 15 days was 840 mls 1170 mls and 1690 mls from the 1 kg, 2 kg and 3 kg weights respectively. Total biogas yield obtained without starter culture was 4355 mls, 5325 mls and 6700 mls from the 1 kg, 2 kg and 3 kg weights respectively and 4865 mls, 5935 mls and 7822 mls within 45 days with starter culture. Results, show that biogas volume vary significantly, [F(2, 16) = 14.93, P < 0.001] with and [F(2, 16) = 19.42, P < 0.001] without starter culture at the 1% level of significance due to weights. There was also significant difference [F(2,16) =16.45, P<0.001] with starter culture and [F(2,16)=25.05, P<0.001] without starter culture. Positive correlation was observed in biogas production with and without starter culture. There was evidence of synergy in the consortium of waste for biogas generation.