Generating energy from trash in Sarasota
A pipeline collects methane from the compacted trash.
By Andrea Thrower, Pia Jasinski and Yamile Escobar
As solid waste decomposes in a landfill, it generates methane, a greenhouse gas. Methane has become a major environmental threat—28 to 36 times more effective than CO2 at trapping heat in the atmosphere over a 100-year period, according to Environmental Protection Agency reports. Methane comes from both natural and man-made sources. (The largest man-made source of industrial methane emissions is the oil and natural gas industry.)
Municipal solid waste landfills are the third-largest human-related source of methane in the United States. In 2016, they accounted for 14% of man-made methane emissions.
Landfill gas is roughly half methane and half carbon dioxide (CO2). When solid waste is deposited in a landfill, it undergoes an aerobic (with oxygen) decomposition stage when little methane is generated. But within less than a year, anaerobic conditions are established, and methane-producing bacteria begin to decompose the waste.
The good news is that methane emissions from landfills can be captured and used as a significant energy resource. In Florida there are five landfills that capture methane gas so that it can be converted into energy. These are in Collier, Sarasota, Lee, Marion and Miami-Dade counties.
Interest in landfill gas collection has increased, thanks in part to the EPA’s Landfill Methane Outreach Program (LMOP), established in 1994 to promote landfill gas energy projects. Federal and state incentives have also helped. Between 1990 and 2015, more and more methane has been recovered and combusted at landfills (increasing 11% year over year). It hasn’t been enough, however, to keep methane emissions in check. Net methane generation continues to grow along with the U.S. population.
