Global methane emissions from landfill are estimated to be between 30 and 70 million tons each year. Most of this landfill methane currently comes from developed countries, where the levels of waste tend to be highest. Landfills provide ideal conditions for methane generation. The huge amounts of waste that are buried in landfill sites can mean that methane can be produced for many years after the site is closed, due to the waste slowly decaying under the ground. Methane escapes from landfills either directly to the atmosphere or by diffusion through the cover soil. Highly active communities of methane consuming bacteria can develop in these overlying soils. These can greatly reduce the amounts of methane emitted. In recent years, several world governments have identified landfill methane emission as a greenhouse gas source that can be both easily defined and reduced. Aside from the practice of covering landfills with a thick soil layer, to promote methane uptake by soil bacteria, more proactive strategies are also available. Methane recovery systems are now commonly installed at landfill sites and these can reduce emissions to the atmosphere by more than half. Sometimes the recovered methane is flared off, producing the less powerful greenhouse gas, carbon dioxide. However, these methane recovery systems can also provide an economically viable energy source, with the collected methane being used in electricity generation. Using the methane as a fuel to produce heat or electrical power is more efficient means of methane conversion to CO2 than simply by burning in flare towers. Fueling some types of internal combustion engines requires methane concentrations as low as 25% meaning even smaller landfill sites can be useful as fuel sources provided there is a reliable and inexpensive way to monitor the “quality” of the methane being produced. The Andros 6511 NDIR bench and electronics is such a product. Capable of measuring low (10 ppm) concentrations of methane for system leak identification up to 100% methane concentrations for combustion control, the Andros 6511 also includes CO2 and CO measurement with capability to add O2 measurement. These four (4) combined gas measurements can provide precise measurement and control of fuel air ratio to ensure maximum energy extraction of the methane being produced.
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