PERFORMANCE STUDY OF ANAEROBIC DIGESTION OF ORGANIC MUNICIPAL WASTE IN UPFLOW BIOREACTOR WITH CENTRAL SUBSTRATE DISPENSER

摘要

A performance study of anaerobic digestion of organic municipal waste in upflow bioreactor with central substrate dispenser is presented. The experimental rig is based on an integrated system of bioreactors consisting of Upflow Bioreactor (UB), Upflow Bioreactor with Central Subtrate Dispenser (UBCSD), and Continous Stirred Tank Reactor (CSTR) each having internal volume of 76 litres, 64.8 litres, and 76 litres respectively. The scheme is used for minimizing the mixing and fouling problems associated with some conventional bioreactors during digestion reaction. Organic municipal waste (OMW) was used to prepare the slurry for the reactors. Microbial reaction was enhanced during operation using a measured quantity (2kg) of substances from the rumen of a newly slaughtered cow. The experimentation from feeder tank to Bioreactors was carried out for a period of 10-days Hydraulic Retention Time (HRT) at 37°C. Effects of some basic parameters affecting anaerobic digestion in terms of biogas production and Chemical Oxygen Demand (COD) reduction were carried out. They include substrate temperature, minimal average temperature, changes in temperature, substrate content and properties, available nutrient, retention time, organic loading rate, pH level, nitrogen inhibition and C/N ratio, substrate agitation, and inhibitory factors. Results showed that UBSCD generated the highest level of Biogas yield of up to 52915 ml, while UB and CSTR yielded 23550ml and 28980ml respectively. Similarly for COD removal, 24343 mg/l, 5775.4 mg/l, and 23155 mg/l were achieved for UBCSD, UB and CSTR respectively from an initial value of 120,320 mg/l. These results show that the use of UBCSD better enhances biofuel production from organic municipal waste.