Biogas production as energy source and strategy for managing waste and climate change

The study presents technical and economic approaches of upscaled laboratory experiment using yard waste (YW) and heterogeneous slurry (HS) to produce heat and power, as a means of bridging the gap between energy production and climate change management strategies. A combination of YW:HS in ratio 2:3 with slurry obtained from a functional digester serving as inoculum was fed into the digester. These were mixed in the ratios of substrates/inoculum/water of 3.5:0.173:6.28 and theoretically upscaled for field-scale biodigesters. The modeled result shows that about 2.5 m3 gas is produced per 5-m3-sized digester over a 30-day hydraulic retention time and estimated project life of 20 years. A business model was adopted for cost recovery of the proposed waste-to-energy system and life cycle cost analysis for the production costs of the seven 5-m3 digesters. Avoided emissions of CO2 from other equivalent energy sources are 4.36 kg, 10.16 kg, 10.37 kg, and 81.32 kg, respectively, for LPG, kerosene, diesel and fuel wood/charcoal. The project is sustainable in for profit, people and planet.