Anaerobic digestion of the organic fraction of municipal solid waste in a simulated bioreactor to improve predictive modeling of landfill systems

Abstract

Municipal solid waste (MSW) generation is increasing globally, containing up to 57 % organic matter. Trapping and extraction of methane (CH4) produced via anaerobic digestion (AD) of the organic fraction of MSW (OFMSW) reduces CH4 released from landfills into the atmosphere. To estimate CH4 production from OFMSW, mathematical models are frequently used, but their accuracy varies under the non-ideal conditions that are inevitable in real landfilling scenarios. This work calibrates first-order decay (FOD) and Gompertz models for predicting CH4 production from the OFMSW based on experimental results from a pilot-scale landfill bioreactor operating under non-ideal conditions, namely under dry and mesophilic conditions with low leachate recirculation inteded to represent landfills in developing countries. This study achieved a 73 % and 66 % reduction in volatile solids (VS) and total solids (TS), respectively, demonstrating successful organic degradation. Models were calibrated using laboratory data, showing high correlation and accuracy >80 % in a Chemical Oxygen Demand (COD) mass balance. The experiment produced 104.3 mL CH4 g−1 VS with accurate predictions from calibrated models Non-calibrated models, however, overestimated methane production by 75 %. Work highlights the importance of modifying models for non-ideal conditions, and results provide useful information for landfills in developing countries.