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Waste Management Mitigation Opportunities Global
Sources: Climate Change 2001 Synthesis Report p 323, Climate Change 2001 WGIII Mitigation Section 3.7, David Suzuki Foundation website: http://www.davidsuzuki.org/Climate_Change/Solutions/Landfills.asp
Waste and waste management affect the release of greenhouse gases in five major ways:
(1) landfill emissions of methane;
(2) reductions in fossil fuel use by substituting energy recovery from waste combustion;
(3) reduction in energy consumption and process gas releases in extractive and manufacturing industries, as a result of recycling;
(4) carbon sequestration in forests, caused by decreased demand for virgin paper; and
(5) energy used in the transport of waste for disposal or recycling.
Except for the long-range transport of glass for reuse or recycling, transport emissions of secondary materials are often one or two orders of magnitude smaller than the other four factors.
Landfill: Worldwide, the dominant methods of waste disposal are landfills and open dumps. Although these disposal methods often have lower first costs, they may contribute to serious local air and water pollution, and they release landfill gas (LFG). LFG is produced when bacteria decompose organic material, such as food, yard waste, diapers, paper and cardboard, in the absence of oxygen. This happens when waste is buried and is called anaerobic digestion. LFG is about 50%-60% methane, 40%-45% CO2 with traces of other organic gases.
The use of LFG for heat and electric power is growing because of policies in countries like Germany, Switzerland, the European Union and the USA. US regulations now require capture of an average of 40% of all landfill methane nationwide. A number of facilities capture LFG and use it in gas turbines to generate electricity. The City of Toronto receives $2.5 million per year from its landfill gas electricity projects. (http://www.davidsuzuki.org/Climate_Change/Solutions/Landfills.asp)
Recycling and Reuse: Recycling involves the collection of materials during production or at the end of a product’s useful lifetime for reuse in the manufacturing process. Recycling processes can be as simple as re-melting of glass, aluminum, or steel. It can involve breaking apart and remaking of paper or other fibres (e.g., textiles or carpets). Recycling can be as complex as chemical breakdown of plastics and synthetic fibres into their individual molecular building blocks, then using these instead of new petrochemicals to synthesize new polymers.
In many cases, manufacturing products from recycled materials is less energy intensive and associated with fewer GHG (greenhouse gas) emissions than making products from virgin materials. This is especially true for aluminum and steel, which are energy intensive and release significant process GHG’s during production (that is CO2 and PFCs).
Composting: Composting happens when bacteria and other organisms digest organic waste. Bacteria need oxygen to digest the waste properly. This is called aerobic digestion. The decomposed matter can be used as a soil conditioner. Research shows that using compost can reduce the USA fertilizer requirements by at least 20%. This would significantly reduce net GHG emissions. Other new opportunities involve anaerobic digestion of agricultural and food industry wastes to produce methane gas.
Biogas facilities produce methane as a substitute for fossil fuels, reducing GHG emissions. In Germany and Switzerland, pilot projects compress the methane from biogas plants and supply it to natural gas vehicles. Canadian engineers have completed a pilot project using a mixture of waste-activated sludge, food waste, industrial sludge from potato processing, and municipal waste paper.