Assessment of Biogas Potential of Codigested Cow Manure with Soymilk Dreg

The use of amendment of Soymilk Dreg (SMd) substrate to improved biogas yield from Cow Manure (Cm) substrate was investigated and duplicate batch experiments were carried out at 4 g VS/L, in eight 2 L volume polyethylene biodigester, with 1.8 L working volume using 144 mL of inoculum throughout the experiments, for 30 days at a fixed temperature of 33 °C. The substrates were divided to three ratios (Cm: SMd (%)); 2:1(50 %), 3:1(33 %) and 4:1(25 %) and a control with only Cm in biodigesters labelled A, B, C and Control. The results shows that biodigesters A, B and C recorded biogas volumes of 25.96, 23.51 and 18.46 % above the control and the bioCH4 composition of biodigesters A, B and C were 50.48, 47.08 and 40.00 % higher than the control. It was concluded that the presence of SMd provided a balanced substrate composition, supporting a stable methanogenic activity across treatments and higher biogas and bioCH4 yields. It is recommended that 25 % SMd (volatile solid) amendment should be codigested with Cm for optimal biogas production.