Modification of plastic tank for bio-digestion of food wastes for biogas generation for cooking foods

Abstract

The anaerobic states of the modified bio-digester and potentials of the generated biogas in cooking foods were evaluated. The study adopted experimental design. Data generated were analyzed using one-way analysis of variance and independent t-test. Carbon, free fatty acid, chemical and biochemical oxygen demand decreased significantly (p<0.05) while moisture and protein contents of the wastes increased significantly (p<0.05) after digestion. The 50% cow dung and 50% yam peel, and 50% cow dung and 50% vegetable had significantly (p<0.05) higher total (12.48%) and volatile (8.10%) solid contents respectively before digestion, but decreased significantly (p<0.05) after digestion. The pH of fermenting slurry was changing in line with the condition within the digester. Bacillus spp., Escherichia coli, klebsiella, Salmonella, Staphylococcus and Streptococcus were predominant microorganisms in all stages of biogas production from different wastes. Biogas generated from the wastes cooked significantly (p<0.05) faster than kerosene but not faster than liquefied petroleum gas. Cooking with biogas did not have any significant (p>0.05) effect on the proximate and sensory characteristics of foods when compared with the foods cooked with liquefied natural gas and kerosene.