Increased biogas production using microbial stimulants

Laboratory studies were undertaken to evaluate the effect of microbial stimulants Aquasan® and Teresan®, on biogas yields from cattle dung and combined residues of cattle dung and kitchen waste, respectively. The addition of single dose of Aquasan® at the rate of 10, 15 and 20 ppm to cattle dung on the first day of incubation resulted in increased gas yields ranging between 45.1 and 62.1 l/kg dry matter. Subsequent addition of Aquasan® at 15 and 20 ppm dosage after a period of 15 days increased the gas yields by 15–16%. The gas production was found to be optimum at a dosage level of 15 ppm and was 39% and 55% higher with single and dual additions, respectively, than untreated cattle dung. In another bench scale study (1:1 dry matter) the addition of Teresan® at 10 ppm concentration to the mixed residues of cattle dung and kitchen wastes at different solids concentration, produced 34.8% more gas (272.4 l/ kg d.m.) than the uninoculated mixture at 15% TS concentration (202.4 l/kg d.m.).