Landfill gas is generated
during the decomposition of organic solid waste 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. Municipal
solid waste landfills are the largest source of human-related
methane emissions. At the same time, methane emissions
from landfills represent a lost opportunity to capture
and use a significant energy resource. It can be used
as a fuel and substitute for natural gas or other carbon
based fuels.
Methane
is a potent "greenhouse" gas. Its contribution
to global warming is 21 times that of carbon dioxide.
Landfills are responsible for almost 40% of anthropogenic
methane emissions in North America. The volatile organic
compounds in these gases interact with nitrous oxides
to form ozone, a primary cause of smog. Methane is also
potentially hazardous since it is explosive in concentrations
between 5 and 15 percent by volume.
Landfill gas also has
very small amounts of other contaminants that even in
these very low concentrations can cause unpleasant odors
potentially resulting in landfill complaints from neighbours.
On the positive side,
Landfill Gas is a medium-BTU energy source that can
be used in engines or turbines to generate electricity
or be used directly to make steam, or fuel other industrial
appliances such as boilers or furnaces. Such uses also
displace the need for burning nonrenewable energy resources,
and can potentially delay the need for building new
power plants.
