Enhancement Of Biogas From Abattoir Cow Liquor Waste With Some Agro-Industrial Wastes

Abstract

An investigation was carried out on the production of biogas from abattoir cow liquor waste (CLW) on biogas production of some agroindustrial wastes. The wastes; brewery spent grain (BS), cassava waste water (CW) and carbonated soft drink sludge (CS) were combined with definite proportions of cow liquor waste to produce biogas under anaerobic digestion for a 25 day retention period. The wastes were combined in the ratios: CLW:BS (1:1), CLW:CS (3:1) and CLW:CW (1:3). The results obtained indicated increased biogas production when BS and CW were inoculated with CLW, while it had a negative effect on CS.The mean biogas production of BS and CS were 8.72 and 8.12 L, respectively, while CW had no biogas production. When inoculated with CLW, the mean biogas production of BS increased to 24.28 L. CW experienced gas production with mean biogas yield of 8.36 L while the gas production of CS reduced to 2.84 L. The CLW:BS blend had the shortest time lag from gas production to onset of gas flammability of 7 days while CLW:CW and CLW:CS had time lag of 10 and 11 days respectively. The retention times for the CLW:CW and CLW:CS was 17 and 21 days, respectively. Overall results indicated that while the low biogas and/or flammable biogas production of brewery spent grain could be enhanced significantly in the presence of cow liquor waste. Cassava waste water which could not produce biogas could be made to be a cheap source of biogas by inoculating it with cow liquor waste