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is <br />Environmental Consultants 4730 Enterprise Way 209 545-8490 <br />and Contractors Suite A FAX 209 545-8391 <br />Modesto, CA 95356 www.scsengineers.com <br />April 1, 2015 <br />File No. 07215028.00 <br />Ms. Erin Fanning <br />Forward Landfill <br />9999 South Austin Road <br />Manteca, California 95335 <br />Subject: First Quarter 2015, Perimeter Landfill Gas (LFG) Monitoring Probe and On -Site <br />Structure Testing at the Forward Landfill, Manteca, California <br />Dear Ms. Fanning: <br />This letter provides results of gas monitoring probes (GMP) and on-site structure testing for the <br />first quarter of 2015 (January through March) performed by SCS Field Services (SCS). All <br />testing, monitoring protocols and reporting were performed in general conformance with Title 27 <br />California Code of Regulations (CCR) Article 6. Briefly, these regulations require that solid <br />• waste disposal site owners/operators implement LFG control or monitoring provisions to ensure <br />that methane gas concentrations in soils at the property boundary do not exceed the lower <br />explosive limit (LEL, or 5 percent by volume) and that interiors of on-site structures do not <br />exceed 1.25 percent by volume in air. Below is a summary of our quarterly monitoring activities. <br />SUMMARY AND CONCLUSIONS <br />On January 13 and February 2, 13 and 18, 2015, no methane gas (the combustible component of <br />LFG) in excess of the LEL was detected at any perimeter subsurface compliance GP probe <br />location tested or in excess of 1.25 percent by volume in air at any interior locations or on-site <br />structures. These results indicate that at the time of our testing the subject site perimeter <br />subsurface GP probes and interiors of on-site structures are in compliance with requirements of <br />Title 27 CCR. <br />GAS TESTING INSTRUMENTATION AND METHODS <br />Testing for methane gas, oxygen gas, carbon dioxide gas and pressure was performed using a <br />Landtec GEM -5000 or Gastech GT -302 Gas Analyzer calibrated to methane gas. These <br />instruments measure combustible gas concentrations in air directly on either of two scales, the first <br />as percent by volume of the lower explosive limit (LEL) of methane gas in air (0 to 5 percent); the <br />other as percent by volume (0 to 100 percent) in the gas sampled. The detection limit for both <br />instruments is approximately 0. 10 percent by volume. <br />C] <br />E <br />