The potential of biological methane generation from chicken manure

Abstract

AbstractThe potential for biological methane generating from the manure of laying hens was investigated in the laboratory. Fresh manure was collected, analyzed, and used to prepare medium for bacterial growth. At 55°C and under anaerobic conditions, methanogenic cultures were initiated by incubating the medium with different inoculations from various natural environments. Since there were no significant differences in gas production among these initiated cultures after 40 days of acclimation, they were mixed to maintain a genetic pool. The mixed culture was then challenged with different retention times (RT) and different volatile solid (VS) concentrations for the selection of optimal conditions and cultures. The conditions were finally selected to be 4‐day RT and 6% VS for the maximal rate of gas production. The optimal pH and temperature were determined to be 7.5 and 50°C, respectively. Under such conditions the selected culture produced total gas at a rate 4.5 L/L day and methane (70% of total gas) 3.2 L/L day. The chicken manure therefore was able to support the methane yield at 270 L/kg of VS, a value comparably higher than other kinds of livestock wastes.