Abstract

Blends of ash solution and water-soaked bagasse with cow dung inoculum were studied for biogas production. Two sets of five biodigesters each of 50 kg capacity were used. The blends were respectively charged into the 50 kg metal prototype biodigesters in the ratio of 3:1 (water:waste). Proximate analyses as well as total solids, volatile solids, carbon content, and calorific value were conducted on the wastes while microbial level, pH and temperature were determined on the slurry. The wastes were subjected to anaerobic digestion for 35 days at mesophilic temperature range of 29 to 31°C. Relative humidity, ambient temperature, pH, slurry temperature, and volume of gas were monitored and recorded on daily basis. Cumulative biogas yields of all the ash solution treated bagasse blends were higher than those of the water-soaked blends by up to 400%. However, the blending of bagasse with cow dung did not improve the biogas yield of bagasse; instead, a steady state was established due to mutual inhibitions. Onset of gas flammability was observed on the 4th day for bagasse and its blends while for cow dung alone, it was observed on the 5th day.

Key words: Bagasse, cow dung inoculum, ash solution treatment, anaerobic digestion, mutual inhibition.