Energy Potential of Biomethane from Municipal Solid Waste in Brazilian Cities Using an Adjusted LandGEM Approach

Resumo

Sanitary landfills for municipal solid waste (MSW) represent a significant and still underutilized source of renewable energy, especially in developing countries where disposal in dumpsites and landfills remains the primary form of final waste disposition. Brazil presents favorable conditions for the utilization of landfill biomethane due to the high organic matter content of its MSW and its tropical climate, which intensifies anaerobic degradation rates. This study evaluates methane generation and the energy recovery potential associated with MSW disposal in two Brazilian municipalities — Salvador and Feira de Santana — using a first-order decay model based on the LandGEM methodology from the United States Environmental Protection Agency (USEPA). Model parameters were adjusted to Brazilian conditions, adopting a methane generation potential (L₀) of 170 m³ CH₄/Mg MSW and a decay constant (k) of 0.05 yr⁻¹ for both Feira de Santana (tropical climate) and Salvador (tropical superhumid climate), both classified as non-arid according to the LandGEM criterion. Historical waste collection data and future projections, assuming an annual growth rate of 5%, were used to estimate methane generation until 2062 for Salvador and until 2075 for Feira de Santana, adopting the 80-year operational lifetime established by LandGEM. The results indicate a peak methane generation of 2.5 × 10⁸ m³ CH₄/year and a total of 5.9 × 10⁹ m³
CH₄ for the analyzed period, corresponding to electricity generation potentials of 49 MW. This demonstrates that landfill biomethane utilization can significantly contribute to Brazil's renewable energy matrix, substituting natural gas, and highlights the importance of integrating waste-to-energy solutions into national energy policies.