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Landfill gas
Landfill gas is a mix of different gases created by the action of microorganisms within a landfill as they decompose organic waste, including for example, food waste and paper waste. Landfill gas is a type of biogas, which is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Landfill gas often contains nitrogen gas that is pulled in from the atmosphere during collection. Trace amounts of non-methane volatile organic compounds (VOCs), siloxanes, and hydrogen sulfide comprise the remainder (<1%). These trace gases include a large array of species, mainly simple hydrocarbons.
Landfill gases have an influence on climate change. The major components are CO2 and methane, both of which are greenhouse gases. Methane in the atmosphere is a far more potent greenhouse gas with a global warming potential of 27 over a one-hundred year period. Landfills are the third-largest source of methane in the US.
Because of the significant negative effects of these gases, regulatory regimes have been set up to monitor landfill gas, reduce the amount of biodegradable content in municipal waste, and to create landfill gas utilization strategies, which include gas flaring or capture for electricity generation.
Landfill gases are the result of three processes:
The first two depend strongly on the nature of the waste. The dominant process in most landfills is the third process, whereby anaerobic bacteria decompose organic waste to produce biogas, which consists of methane and carbon dioxide together with traces of other compounds. Despite the heterogeneity of waste, the evolution of gases follows well defined kinetic pattern. Formation of methane and CO2 commences about six months after depositing the landfill material. The evolution of gas reaches a maximum at about 20 years, then declines over the course of decades.
Conditions and changes within the landfill can be observed with electrical resistivity tomography (ERT) to detect sources of landfill gas, and leachate movements and pathways. Conditions at different locations, such as temperature, moisture levels and fraction of biodegradable material, can be inferred. This information can be used to improve gas production, with optimal well locations over hotspots and interventions such as heap irrigation.
When landfill gas permeates through a soil cover, a fraction of the methane in the gas is oxidized microbially to CO2.
Because gases produced by landfills are both valuable and sometimes hazardous, monitoring techniques have been developed. Flame ionization detectors can be used to measure methane levels as well as total VOC levels. Surface monitoring and sub-surface monitoring as well as monitoring of the ambient air is carried out. In the U.S., under the Clean Air Act of 1990, it is required that many large landfills install gas collection and control systems, which means that at the very least the facilities must collect and flare the gas.
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Landfill gas AI simulator
(@Landfill gas_simulator)
Landfill gas
Landfill gas is a mix of different gases created by the action of microorganisms within a landfill as they decompose organic waste, including for example, food waste and paper waste. Landfill gas is a type of biogas, which is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Landfill gas often contains nitrogen gas that is pulled in from the atmosphere during collection. Trace amounts of non-methane volatile organic compounds (VOCs), siloxanes, and hydrogen sulfide comprise the remainder (<1%). These trace gases include a large array of species, mainly simple hydrocarbons.
Landfill gases have an influence on climate change. The major components are CO2 and methane, both of which are greenhouse gases. Methane in the atmosphere is a far more potent greenhouse gas with a global warming potential of 27 over a one-hundred year period. Landfills are the third-largest source of methane in the US.
Because of the significant negative effects of these gases, regulatory regimes have been set up to monitor landfill gas, reduce the amount of biodegradable content in municipal waste, and to create landfill gas utilization strategies, which include gas flaring or capture for electricity generation.
Landfill gases are the result of three processes:
The first two depend strongly on the nature of the waste. The dominant process in most landfills is the third process, whereby anaerobic bacteria decompose organic waste to produce biogas, which consists of methane and carbon dioxide together with traces of other compounds. Despite the heterogeneity of waste, the evolution of gases follows well defined kinetic pattern. Formation of methane and CO2 commences about six months after depositing the landfill material. The evolution of gas reaches a maximum at about 20 years, then declines over the course of decades.
Conditions and changes within the landfill can be observed with electrical resistivity tomography (ERT) to detect sources of landfill gas, and leachate movements and pathways. Conditions at different locations, such as temperature, moisture levels and fraction of biodegradable material, can be inferred. This information can be used to improve gas production, with optimal well locations over hotspots and interventions such as heap irrigation.
When landfill gas permeates through a soil cover, a fraction of the methane in the gas is oxidized microbially to CO2.
Because gases produced by landfills are both valuable and sometimes hazardous, monitoring techniques have been developed. Flame ionization detectors can be used to measure methane levels as well as total VOC levels. Surface monitoring and sub-surface monitoring as well as monitoring of the ambient air is carried out. In the U.S., under the Clean Air Act of 1990, it is required that many large landfills install gas collection and control systems, which means that at the very least the facilities must collect and flare the gas.