CORRESPONDENCE_1992-1993 - Laserfiche WebLink

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LANDFILL GAS MONITORING REPORT The Harney Lane Sanitary Landfill is located on Harney Lane approximately seven miles east of Lodi (Figure 1) . A migrant farm labor camp is located adjacent to the landfill along the western boundary. The structures in the labor camp are occupied part of the year by farm workers. In accordance with closure regulations, a network of perimeter gas monitoring wells were installed by EMCON Associates in October, 1991 (Figure 2) . The wells were to be no more than 1, 000 feet apart and are spaced much closer than 1, 000 feet together along the boundary with the labor camp to ensure detection of possible methane migration toward the structures. Each well contains three monitoring probes set at varying depths. According to closure regulations, the wells are to be monitored quarterly for methane. However, in a letter dated December 19, 1991, the Local Enforcement Agency (LEA) required six monthly gas monitoring events for the perimeter landfill gas monitoring wells. In addition, the LEA required three monthly events for on-site structures and farm labor camp structures. Two monthly probe monitoring events, nts, one on-site structure monitoring event, and two labor camp events have been performed by EMCON Associates. The County recently purchased a Gas Tech Landfill Monitor Meter, and trained County engineers to perform the gas monitoring. During the monitoring event on April 22, 1992 , the meter gave questionable results and, subsequently, was returned to the factory for repairs. Therefore, the monthly monitoring program was postponed. The landfill gas monitor was repaired, and the County received it from Gas Tech on June 22, 1992 . Monthly monitoring of probes and on-site structures was resumed on June 25, 1992 . The County has performed two probe monitoring events and two on- site structure events. LABOR CAMP STRUCTURE MONITORING Results from the first structure monitoring event and the first two probe monitoring events were submitted previously. on April 21, 1992, EMCON Associates performed the second monitoring event in selected units of the migrant farm labor camp adjacent to the Harney Lane Sanitary Landfill. EMCON used a Foxboro organic vapor analyzer (OVA) 128 flame ionization detector (FID) . The instrument detection limit was 0.4 parts per million by. volume (ppmv) of methane. EMCON calibrated the instrument to an assumed baseline background methane concentration of 1 ppmv. 2