Production and storage of biogas from ash-treated and untreated bagasse

A comparative study of biogas production from ash-treated and untreated bagasse and its storage was investigated. Both wastes were charged into two 200L metal prototype biodigesters in the ratio of 3:1 (water:waste). The first biodigester contained partially hydrolyzed untreated bagasse while the second contained bagasse which was soaked in ash-treated water for one week. Proximate analyses as well as total solids, volatile solids, carbon content and calorific value were conducted on the waste while microbial level, PH and temperature were determined on the slurry. The wastes were subjected to anaerobic digestion for 30 days at mesophilic temperature range of 25 to 33oC. Relative humidity, ambient temperature, PH, slurry temperature and volume of gas were monitored and recorded on daily basis throughout the retention period. Biogas yield of ash-treated waste (1184.3 L) was four times higher than that of untreated waste (288.8 L). Onset of gas flammability was observed on the 4th day for both samples and was sustained throughout the retention period. The gas produced in each case was analysed and found to contain 64% methane. Storage was achieved with a modified pressure pump and maximum pressure of 23.2 MPa was recorded with a corresponding cooking time of 3.75 hours.