Laserfiche WebLink
`°N��� Fact Sheet <br />For Public Availability Session <br />'ism mote September 16, 1993 <br />Washington County Government Center - Board Room <br />Methane Gas <br />Washington County Sanitary Landfill No. 1 <br />SUMMARY Methane gas at landfills is produced by decomposing waste. The gas can travel underground and <br />enter homes and businesses where it can accumulate to explosive levels. In 1992, after 14 years of monitoring, <br />the closed Washington County Sanitary Landfill site in Lake Elmo, Minnesota was found to contain methane <br />levels requiring attention. Ramsey and Washington Counties began studies in 1992 that will result in the <br />construction of a methane gas extraction system during the autumn of 1993. <br />WHAT IS THE EPA ORDER? The Counties stepped up their monitoring program at their own initiative. when <br />higher methane levels were first found in 1992 and later to comply with an order issued by the U.S. <br />Environmental Protection Agency on February 17, 1993. This Order requires the Counties to implement gas <br />treatment and monitoring activities to satisfy EPA standards for on -site structures and at the property boundary. <br />( )W HAS THE INVESTIGATION UNFOLDED? <br />1. Using five monitoring vents, located on the site <br />perimeter, the Counties have monitored the landfill <br />for methane gas on a quarterly basis since 1978. <br />Until 1992, the monitoring never consistently found <br />methane and levels were never found above EPA <br />standards. <br />2. In September 1992, the Minnesota Pollution Control <br />Agency (MPCA) detected methane in surface soils <br />at the site. The Counties conducted a "soil -gas" <br />survey to look for methane in the soil. They found <br />methane above EPA standards along the western <br />boundary near Lake Elmo's Fire Station No. 2. <br />3. In January and March of 1993, the Counties installed <br />six sets of nested monitoring vents along the <br />landfill's western boundary. Monitoring confirmed <br />that methane gas was migrating off -site. <br />METHANE MONITOR 0 400 800 <br />INSTALLED <br />RRMIRP _. <br />GRAPHIC SCALE IN FEET <br />C3n' _ <br />1 LANDFILL--- <br />BOUNDARY <br />R u <br />BARRIER <br />d <br />TETRACTION. <br />VENT SYSTEM <br />CIOe <br />I <br />OMo <br />{IRE <br />SrArxW Tt <br />07 <br />CG Sr OC2 <br />,a <br />II <br />__ <br />ICI <br />BOUNDARY <br />dal <br />BOUNDARY <br />�. To assure the safety of people working at the fire station, a continuous methane monitor was installed. <br />In addition, homes near the landfill were surveyed for methane in February and weekly between March <br />and July 1993. Explosive levels of gas have not been found. <br />