Problem of Fugitive Gas Emissions from Municipal Solid Waste Landfills

Abstract Submission: Landfills are a pivotal component of global waste management, serving as the primary method for disposing of a substantial portion of municipal solid waste (MSW). In 2018, the U.S. generated 292.4 million tons of MSW, with around 50% deposited in landfills. MSW decomposes anaerobically in landfills, producing landfill gases (LFG) that consist of roughly 50% methane (CH4), 50% carbon dioxide (CO2), and trace amounts of hydrogen sulfide (H2S) and non-methane organic compounds (NMOCs). In 2022, MSW landfills were the third-largest anthropogenic source of CH4 in the U.S., accounting for 103.7 MMT of CO2 equivalent, representing 14.4% of total CH4 emissions. As landfilling remains the predominant waste disposal method, these emissions are expected to rise. CH4 emissions are of particular concern due to CH4's global warming potential, which is at least 28 times greater than CO2 over 100 years, contributing significantly to climate change. Additionally, CH4 is a highly flammable and explosive gas, with explosive limits between 5% and 15%, posing serious risks to human safety and property if accumulated. Consequently, regulations (40 CFR 60) require LFG capture if CH4 levels exceed 500 ppmv or NMOCs exceed specified limits. Additionally, H2S poses health risks and can create odor problems. To manage LFG, modern landfills employ soil covers and gas collection systems. These methods aim to prevent gas escape, capturing emissions for energy production or flaring. However, these measures have limited effectiveness; soil covers only partially capture LFG, and gas wells have a limited radius of influence, leading to continued fugitive emissions. Although various methods exist for measuring LFG emissions, effective strategies for mitigating CH4, CO2, H2S, and other trace gases are still limited. Our recent research has developed a novel and sustainable biogeochemical cover system to significantly reduce landfill gas emissions, which will be further discussed.

Learning Objectives/Expected Outcome (Optional) :