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WHAT IS LANDFILL GAS
Landfill Gas (LFG) is a product of the natural
decomposition of municipal solid
waste (MSW) in landfills. Properly constructed
and operated landfills inherently
restrict the air that comes in contact with
MSW once compacted and covered.
The absence of oxygen (anaerobic) in the
decomposition process of the MSW
yields a mixture of gasses, collectively
referred to as LFG, primarily composed of
40 to 60 percent methane and 35 to 50 percent
carbon dioxide. Some amount of
nitrogen, oxygen, and volatile organic compounds
may be found in the LFG.
(Click
here for a cross-section of a landfill)
If left uncontrolled, LFG migrates out of
the landfill, either below the surface through
groundwater or above the surface as emissions
to atmosphere. Carbon dioxide has
been determined to contribute to the greenhouse
effect, credited with an impact on
global warming. The greenhouse characteristics
of methane are more than 20 times
worse than those of carbon dioxide. Environmental
regulations are in place to control
LFG emissions through flares, but landfill-gas-to-energy
(LFGTE) projects reduce
overall emissions further still, by utilizing
LFG as a substitute for fossil fuels normally
used in energy generation.
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