ARCHIVED REPORTS_2006_20 - Laserfiche WebLink

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s k Ms. Christina Carbajal April 24, 2006 Page 2 The gases produced in a landfill will either vent vertically to the atmosphere or migrate horizontally through. subsurface soil to locations on adjacent properties. If the soil surrounding a landfill. consists of permeable materials,there is a greater likelihood that the LFG will migrate to off-site locations. If the methane gas component of LFG is allowed to accumulate in a confined.area (Le.,utility lines, irrigation valve boxes, vaults,basements, wall spaces, etc.) and is exposed to an ignition source, it can be explosive at concentrations between 5 and 15 percent by volume. At higher concentrations,methane gas is flammable. However,the presence of methane gas i.n site soil does not mean there is an immediate threat of explosion because flames cannot typically propagate through soil. Operation Criteria. The most current-Permits to Construct/Operate dated-July 22,2002.and October. S, 2002, issued by,. the San Joaquin.Valley Unified Air Pollution Control District(SJVUAPCD) delineates several main operationalcriteria for the subject system. This operational criteria states that Aare exit gas temperature be maintained ata minimurn of 1400 degrees Fahrenheit during system operation. In addition the systems are to be operated to maintain compliance with SJVUAPCD Title V and Rule 4642 requirements. State California.Code of Regulations (CCR Title 27)requires that solid waste disposal.site ownersfoperators implement LFG control or monitoring provisions to ensure that methane gas concentrations in soil at the property line do not exceed the lower explosive limit (LFT.,, or 5 percent by volume) and that interiors of on-site structures do not exceed 1.25 perce7_t methane ley volume in air. Gres Testi Testing for methane gas (the combustible component of LFG), oxygen gas, carbon dioxide gas, pressure, and temperature was performed using a Landtec Gem-500 Oras Analyzer or comparable unit_ This instrument measures combustible gas concentrations in air directly on either of hVo scales_ the first as percent by volume of the lower explosive limit (LFL)of methane gas in air(5 percent); the second as percent by volume(0 to 100 percent) in the gas sampled. Instrument calibration forrn.s are attached to this report. LFG Monitoring Probes In accordance with the approved testing schedule, LFG Monitoring Probes (GP) are to be tested quarterly or when methane gas concentrations detected exceed. 5 percent by volume_ During this reporting period, all perimeter LFG monitoring probes defined as Nos. 1 through 25 were tested for the presence of LFG. Results indicated that no methane gas concentrations in excess of 5