7.4. SR 05-31-1994 - Laserfiche WebLink

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Landfill Gas March 31. 1994 Page 3 e process by which methane gas is produced and finally, the tendency of the gas to follow the path of least resistance. These are all contributing factors. Landfill gas also includes other potentially harmful substances, such as; volatile organic compounds and inert substances or non-dangerous substances such as Carbon dioxide. It has been estimated that 20 pounds of mixed municipal waste would generate one cubic foot of methane gas. Typically the generation rate of methane will be at its peak with waste that has been buried for twenty years and then will slowly decrease and extend out over a long period of time. As the methane gas travels through the landfill it picks up and carries with it the gases described earlier. . Gas Systems: Landfills have primarily two options available to them to help control the migration of landfill gas from the landfill property. The first is referred to as a ''Passive System" which merely. vents landfill gas into the atmosphere. Elk River Landfill currently has this system in place. However;. passive systems' are very limited, in their ability to control landfill gas migration since the systems typically only effect the upper few feet of the landfill and do not relieve pressure at the base of the facility. These systems also vent methane into the atmosphere which is said to damage the ozone layer. Other harmful substances are also carried into the atmosphere which can have an effect on human and animal life; if that life is over exposed to these substances. The remaining gases that are not relieved through the passive system, travel through soils away from the pressure zone in the landfill. This zone develops as a result of the generation of methane. . Landfill gases can create several problems. Some of these problems include the erosion of the foundations on buildings as a result of the gas coming into contact with them. Another potential problem is methane gas leaking into buildings and ultimately reaching levels that are explosive. This, if activated by a phone, electrical switch or other source of ignition could cause an explosion or fire. This is similar to what has happened in cities when natural gas pipelines leak. e So far, the only danger that ERL's gas generation has presented is the destruction of some trees: as a result of methane being in the root zone, displacing oxygen. ERL has also discovered that methane gas has begun entering some areas of our shop facility. Allowed to continue, however, in a few years this methane gas could represent a threat to other property owners surrounding the facility. It is ERL's intention to stop that from occurring.