Download Gas emissions from waste disposal

CLIMATE CHANGE AND WASTE
The disposal and treatment of waste can produce emissions of several greenhouse gases (GHGs), which contribute to global climate change. The most significant
GHG gas produced from waste is methane. It is released
during the breakdown of organic matter in landfills. Other
forms of waste disposal also produce GHGs but these
are mainly in the form of carbon dioxide (a less powerful
GHG). Even the recycling of waste produces some emissions (although these are offset by the reduction in fossil
fuels that would be required to obtain new raw materials). Waste prevention and recycling help address global
climate change by decreasing the amount of greenhouse
gas emissions and saving energy (Environmental Protection Agency).
GHG emissions and waste management
Composting (an option for organic materials such
as food scraps, yard waste and agricultural waste).
Composting is the natural biological breakdown
of organic material. During the process of aerobic
composting (in the presence of oxygen), microorganisms consume the organic matter and release
heat and carbon dioxide (CO2). However, most of
the carbon contained in the organic matter is retained in the compost and therefore not released
into the atmosphere. Composting is a waste
management system that creates a recycled
product that can be used in place of inorganic
fertilizer. The net GHG emission is reduced because the energy intensive fertilizer production
and associated GHGs are reduced.
Combustion releases both carbon dioxide and
nitrous oxide (around 300 time more potent a
GHG than carbon dioxide, but making up only a
small percentage of the total emissions). Energy
released during combustion can be harnessed
and used to power other processes, which results in an offset of GHG emissions from a reduction fossil fuel use. In addition combustion diverts
waste from landfill, reducing the amount of methane produced. However burning garbage also
produces waste in the form of ash. Most of this
ash is sent to landfill but some is used to make
products like building materials and road base.
In developed countries, the contribution of
waste sector to total greenhouse gas
emissions varies between 1% and 8%
Contribution of various waste management systems
to greenhouse gas emissions, 2002
Regional GHG emissions from waste in 2002:
North America - over 200 million tonnes
European Community - over 100 million tonnes
Japan, Australia and New Zealand - over 50 million tonnes
Finland
Norway
Canada
United States
Estonia
Denmark
United Kingdom
Belgium
Japan
Latvia
Germany
France
Australia
Portugal
New Zealand
In percentage
100
Incineration
50
0
Waste water handing
Italy
Greece
Solid waste disposal
Source: UNFCCC
42
43
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Landfilling is the most common waste
management practice, and results in the
release of methane from the anaerobic decomposition of organic materials. Methane
is around 20 times more potent as a GHG
than carbon dioxide. If the disposal of organic matter were decreased (for example
by composting or combustion) it would be
possible to reduce the amount of methane emissions. However, landfill methane
is also a source of energy, and some
landfills capture and use it for energy. In
addition, many materials in landfills do
not decompose fully, and the carbon that
remains is sequestered in the landfill and
not released into the atmosphere.
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Emissions due to solid waste disposal on land
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Source: UNFCCC
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