Agenda - Council - 10/14/1980 - Laserfiche WebLink

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lqethane gas, a non-corrosive, non-toxic gas, is colorless and odorless, making it impossible to detect with human senses and compounding the problem caused by its entry into a building. The density of methane is less than that of air, so that methane rises in air when l~her~ are no total pressure or par- tial pressure gradients to oppose its rise. The gas within the landfill is generally ~Jnder a slight positive pressure (relative to atmospheric pressure) which causes lateral as well as vertical convective flow; the Bas also moves by n~ans of diffusion which causes gas to travel from voids where it is in relatively high concentration to connected voids where the 9as concentration is lower. As a consequence, methane will escape both vertically and laterally from the landfill, tending to follow the path of' "least resistance" to flow, th.rough per~eable material, pipes, cracks, and other channels or media pro- viding continuity of voids. Generally the majority of the gas will move upward through the soil cover. The recent addition of sludge to the cover soil (sealed 'surface), coupled with the control system being shut down during the summer, apparently was the cause for the gas migrating beyond the property line. A timer mal- function, maintenance and service problems contributed to the migration.