Methane Generation Potential of the Easily Degradable Group of Landfilled Municipal Solid Waste

Municipal solid waste (MSW) remains in sanitary landfills for many years. To maintain a circular economy, assessing the feasibility of reinserting MSW excavated from sanitary landfills into the production chain is important. This reduces environmental impacts, helping to minimize soil, water, and air pollution resulting from the decomposition of waste in landfills. In addition, it promotes economic benefits from the energy recovery of waste, such as biomass, which can generate electricity and heat, contributing to a sustainable energy matrix. The present study aimed to evaluate the easily degradable MSW group with 24 years of landfilling (ED-24) regarding its potential for methane generation. The ED group consisted of putrescible organic matter, wood, paper, cardboard, and pruning landfilled at a sanitary landfill in Southeastern Brazil. The feasibility of valuing ED-24 as a substrate for anaerobic digestion was assessed by analyzing its physical, chemical, and biochemical characterization and calculating its theoretical methane yield (TMY). The total volatile solids (TVS) and holo-cellulose contents of ED-24 were 73.45% and 61.39%, respectively, on a dry-weight basis. These values were in the range of those determined for non-landfilled lignocellulosic materials. Thus, 24 years of landfilling partially degraded the anaerobically lignocellulosic materials. The TMY of ED-24 was 233.41 mL CH4/g TVS, indicating a potential to generate methane. Despite the high lignin value, ED-24 can be valued as a substrate for anaerobic digestion.