Lessons learned by modelling biogas production in an Italian state-of-the-art landfill active for 35 years

"Fossetto" landfill is in operation in the municipality of Monsummano Terme (Tuscany, Italy) since 1988, at its origin, it was used as a controlled landfill where mixed municipal solid waste, without any separate collection, was disposed of. Since 2003, a biogas recovery system is active, while a mechanical-biological treatment (MBT) plant and a reverse osmosis leachate treatment plant that recirculates leachate are installed since 2006. This plant provides long-term biogas monitoring that allowed to calculate, with a simplified methodology, the biogas recovery efficiency. Biogas generation modelling via the USEPA LandGEM model showed that the adoption of MBT grandly reduced the biogas production, while extraction efficiency was calculated at around 40% over the last ten years, lower than expected. Efficient separate collection leading to the reduction of both the incoming waste amount and of its biogas potential production coupled with mechanical biological treatment proved effective to reduce landfill environmental impacts. More research is needed to establish new technologies to further reduce fugitive biogas emissions from the landfill.