Municipal solid waste landfills are the largest source of human-related methane emissions in the United States, accounting for about 34 percent of these emissions. At the same time, methane emissions from landfills represent a lost opportunity to capture and use a significant energy resource. Landfill gas (LFG) is created as solid waste decomposes in a landfill. This gas consists of about 50 percent methane (CH4), the primary component of natural gas, about 50 percent carbon dioxide (CO2), and a small amount of non-methane organic compounds.

Mill Seat is currently managing more than 4,000 cubic feet per minute of landfill gas. This gas is collected and removed through a series of wells located throughout the landfill. To install a gas well, special equipment is used to drill into the waste and a pipe with holes, surrounded by gravel, is inserted to collect the gas flow. The wells are all connected to a central header pipeline, where the gas is currently channeled to a flare for combustion. Instead of allowing LFG to escape into the air, it can be captured, converted, and used as an energy source.

The Mill Seat Landfill is in a unique position to make a meaningful contribution to this effort by harnessing the landfill gas that is being produced onsite, and we’re excited to begin operating our gas-to-electricity facility, which went online in July 2007. Look for updates on this project here and in future issues of Mill Seat Matters.