Landfill gas monitoring

Landfill gas monitoring

Landfill gas monitoring is the process by which gases that are released from landfill are electronically monitored.

Landfill gas production results from chemical reactions and microbes acting upon the waste as the putrescible materials begins break down. [Burdekin, O. (2003) An investigation into the continuous monitoring of landfill gas and the commercial viability of the Intelysis landfill gas monitor, Manchester University, Unpublished thesis] in the landfill Due to the constant production of landfill gas, pressure increases within the landfill provoke its release into the atmosphere. Such emissions lead to important environmental, hygiene and security problems in the landfill. [Brosseau, J. (1994) Trace gas compound emissions from municipal landfill sanitary sites; Atmospheric-Environment 28 (2), 285-293] [Christensen, T. H., Cossu, R. & Stegmann, R. (1999) Landfilling of waste: Biogas] Several accidents have occurred, for example at Loscoe, England in 1986. [Williams and Aitkenhead (1991) Lessons from Loscoe: The uncontrolled migration of landfill gas; The Quarterly Journal of Engineering Geology 24 (2), 191-207] Migrating landfill gas was allowed to build up and destroyed the property. An accident causing two deaths occurred from an explosion in a house adjacent to Skellingsted landfill in Denmark in 1991 [ Danish EPA] . Due to the risk presented by landfill gas there is a clear need to monitor gas produced by landfills. In addition to the risk of fire and explosion, landfill gas migration in the subsurface and result in contact of landfill gas with groundwater. This can result in contamination of groundwater by organic compounds present in nearly all landfill gas [Kerfoot, H.B., Chapter 3.5 In Christensen, T. H., Cossu, R. & Stegmann, R. (1999)Landfilling of waste: Biogas]

Techniques for the monitoring of landfill gas

Surface monitoring is used to check the integrity of caps on waste and check on borehole monitoring. It may give preliminay indications of the migration of gas off-site. The typical regulatory limit of methane is 500 parts per million (ppm) by volume (in California, AB 32 may push this limit down to 200 ppm). Surface monitoring can be broken down into Instantaneous and Integrated. Instantaneous monitoring consists of walking over the surface of the landfill, while carrying a flame ionization detector (FID). Integrated consists of walking over the surface of the landfill, while pumping a sample into a bag. The sample is then read with a FID or sent to a lab for full analysis. Integrated reulatory limits tend to be 50 ppm or less.

Gas probes, also known as perimeter or migration probes, are used for Subsurface monitoring and detect gas concentrations in the local environment around the probe. Sometimes multiple probes are used at different depths at a single point. Probes typically form a ring around a landfill. The distance between probes varies but rarely exceedes 300 metres. The typical regulatory limit of methane here is 50,000 parts per million (ppm) by volume.

Ambient air samplers are used to monitor the air around a landfill for excessive amounts of methane and other gases.

Types of landfill gas monitor

A monitor may be either a
*Single reading monitor, giving point readings for landfill gas composition, or a
*Continuous gas monitor, that remain in boreholes and give continuous readings over time for landfill gas composition and production.

Techniques for establishing landfill gas (rather than liquid) as the source of volatile organic compounds in groundwater samples

Several techniques have been developed for evaluating whether landfill gas (rather than leachate) is the source of volatile organic compounds (VOCs) in groundwater samples. [Kerfoot, H.B., Chapter 3.5 In Christensen, T. H., Cossu, R. & Stegmann, R. (1999)Landfilling of waste: Biogas] Leachate water frequently has elevated levels of tritium compared to background groundwater and a leachate (water) release would increase tritium levels in affected groundwater samples, while landfill gas has been shown not to do so. Although landfill gas components can react with minerals and alter inorganic constituents present in groundwater samples such as alkalinity, calcium , and magnesium, a frequent major leachate constituent, chloride, can be used to evaluate whether leachate has affected the sample.

Highly soluble VOCs, such as MtBE, diethyl ether, and tetrahydrofuran, are evidence of leachate effects, since they are too water-soluble to migrate inlandfill gas. The presence of highly soluble semi-volatile organic compounds, such as phenols, are also consistent with leachate effects on the sample. Elevated concentrations of dissolved CO2 have been shown to be a symptom of landfill gas effects - This is because not all of the CO2 in landfill gas reacts immediately with aquifer minerals, while such reactions are complete in leachate due to the presence of soils as daily cover in the waste. To assess whether VOCs are partitioning into groundwater in a specific location, such as a monitoring well, the headspace gas and dissolved VOC concentrations can be compared. If the Henry's Law constant multiplied by the water concentration is significantly less than the measured gas concentration, the data are consistent with VOCs partitioning from landfill gas into the groundwater.

ee also

*Anaerobic digestion

External links

* [ CIWMB policy]


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Gas flow computer — Originally the gas flow computer was an electronic module that simply provided a dedicated gas flow computer function. Today gas flow computer is a misnomer since the gas flow computer function is a subfunction to an overall data acquisition and… …   Wikipedia

  • Landfill in the UK — See also the Landfill Directive, landfill tax and the Landfill Allowance Trading Scheme Landfill in the UK is currently recognised as the Best practicable environmental option (BPEO) for the disposal of certain waste types. In order to apply the… …   Wikipedia

  • Operating Industries Inc., Landfill — Superfund site Geography City Monterey Park County Los Angeles County State California …   Wikipedia

  • Toyon Canyon Landfill — The Toyon Canyon Landfill was a controversial landfill wholly within Los Angeles Griffith Park. Filling began in 1957 and ended in 1985. A lawsuit in 1959 attempted to stop the project but was unsuccessful. A summary of the lawsuit is available… …   Wikipedia

  • Randolph Farms Landfill — is a 120 acre (486,000 m²) landfill owned by the Balkema family of Kalamazoo, Michigan, located in Randolph County, Indiana. In addition to Randolph County, it serves Delaware, Madison, Jay, Wayne, and Henry Counties in Indiana, as well as Darke… …   Wikipedia

  • Greenhouse gas — Simple diagram of greenhouse effect. A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.[1] …   Wikipedia

  • Biogas — Swamp gas redirects here. For the obsolete theory of emanations from swamps causing disease, see Miasma theory of disease. Pipes carrying biogas (foreground), natural gas and condensate …   Wikipedia

  • Toxicity characteristic leaching procedure — (TCLP) is a soil sample extraction method for chemical analysis employed as an analytical method to simulate leaching through a landfill. The leachate is analysed for substances appropriate to the protocol.The Resource Conservation and Recovery… …   Wikipedia

  • Standpipe — may refer to:*Standpipe (drilling rig):, a thick metal tubing, situated vertically along a derrick, that facilitates the flow of drilling fluid and has attached to it and supports one end of a kelly hose. * Standpipe (firefighting), a rigid… …   Wikipedia

  • Biodegradation — Yellow slime mold growing on a bin of wet paper Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means. The term is often used in relation to ecology, waste… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”