Sustainable Management of Kitchen Waste through Anaerobic Digestion: Influence of pH and Loading Rates on Biogas Yield

Nigeria, the most populous black nation, is confronted with the problem of waste management. Most of the widely used methods of waste management are proving ineffective and there is a need for more scientific and environmentally friendly technologies to meet the challenge headlong. Anaerobic digestion offers such a viable alternative. Batch anaerobic digestion of kitchen waste at different pH values and loading rates was carried out to evaluate the potentials of the process as a means for waste management. A set of nine digesters in a batch mode was used and labelled (A1-A3; B1-B3; and C1-C3). The results showed that digester B2, with loading rate of 400 g/l run at pH 6.5, gave the highest yield of biogas. The yield was 72.62% higher than A1 (200 g/l at pH 5.5) and 11.54% higher than C1 and C3. Furthermore, kinetic study showed that digester B2 had the highest biodegradability, with biogas production rate constant of 0.122/day. Conclusively, anaerobic digestion can be an effective option in treating kitchen waste and generating bioenergy.