Comparative study of biogas production from cocoa pod, maize husk, orange peels, pineapple peels, and coconut fiber co-digested with yeast

The demand and cost of domestic energy in Nigeria are on the increase, primarily due to the increasing human population and demand. This is compounded by desertification, increasing the cost of electricity, industrialization, lack of alternative such as solar, wind and nuclear energy.This study was conducted in crop science laboratory Faculty of Agriculture, University of Benin, Benin City to compare the potential of biogas produced from anaerobic co-digestion of coconut fibre, cocoa pods, maize husk, orange peels, pineapple peels and yeast and to determine the effect of pH and retention time on biogas yield. The experiment was arranged in a completely randomized design with three replicates using a set of five batch reactors. The digesters were labeled A, B, C, D and E respectively. Digester A consist of 2g of yeast, 4g of coconut fibre, digester B consist of 2g of yeast, 4g of cocoa pods, digester C consist of 2g of yeast, 4g of maize husk, digester D consist of 2g of yeast, 4g of orange peels and digester E consist of 2g of yeast, 4g of pineapple peels. The pH was determined before corking the reactors. The results showed significant differences among the different substrate for biogas yield and methane component. Biodegradability of the different substrate, quality and retention time significantly affected the biogas yield in the five digesters. Digester loaded with maize husk produced significantly higher volume of biogas and methane component compared with other substrate. Increase in biogas yield for maize husk of 4g was 23.33ml with methane component of 61.78% for the 10 days hydraulic retention time. The retention time of 4, 5, 6 and 8 days significantly produced the highest volume of biogas. Based on these findings, for obtaining optimum biogas yield, maize husk and yeast blend could be a rich source of renewable energy option and would help arrest ecological disaster in addition to control of deforestation.