DESIGN AND FABRICATION OF AN ANAEROBIC DIGESTER FOR BIOGAS PRODUCTION

Abstract

The rise in the price of fossil fuel coupled with the negative environmental impact of global warming and exhaust emissions has aroused interest of researcher in exploring alternative sources of energy and this research focused on methane production. The project aimed at design and fabrication of a biogas digester using locally sourced materials that is affordable for low income earners. Test was carried out with the fabricated 10 litres anaerobic digester for three (3) different times at 5 litres working volume, for the fermentation of different substrates labeled digester A (pig waste), digester B (poultry droppings) and digester C (cattle dung) with their cumulative biogas production of, 0.438, 0.331 and 0.253m3 respectively, while each was incubated for forty four (42) days at ambient mesophilic temperature of 37±1 oC at an initial pH of 6. 10±10.31 for PW, 6. 51±1.23 for PD and 7. 12±4.65 for CD. The flow was set to the maximum of 7 litres per day in order to fill the reactor of 5 L working volume within the period of 18 to 20 hours. Digester A shows greater yield, its higher biogas production was attributed to better synergy of microorganisms in the digester and the C/N ratio which was within the normal range for optimum biogas production.