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Environmental Consultants 4707 Greenleaf Circle 209 545-8490 <br /> and Contractors Suite F FAX 209 545-8391 <br /> Modesto, CA 95356 www.scsfieldservices.com <br /> October 8, 2010 <br /> File No. 07207048.00 <br /> Mr. Don Litchfield <br /> Forward Landfill <br /> 9999 S. Austin Road <br /> Manteca, California 95336 <br /> Subject: Operation,Monitoring, and Maintenance of the Landfill Gas(LFG)Migration <br /> Control Facilities at the Forward/Austin Landfill, Manteca, California <br /> Dear Mr. Litchfield: <br /> This letter provides a status report on the operation, monitoring, and maintenance (O&M)work <br /> performed by SCS Field Services (SCS) on the subject system. All activities were performed in <br /> accordance with our approved proposal dated August 14, 2007. Below is a summary of O&M <br /> efforts during the period of September 1 through 30, 2010. <br /> OPERATION STATUS AND CONCLUSIONS <br /> As of the dates of our testing,the LFG control facilities appeared to be operating satisfactorily <br /> and generally meeting the operational criteria. During the month of September 2010, no methane <br /> gas concentrations above the LEL were detected at any compliance Perimeter Monitoring Probe <br /> tested by SCS, with the exceptions of LFG Monitoring Probe Nos. GP-10S, GP-11D, GP-11M <br /> and GP-11 S (up to 57.6%by volume). All LFG extraction wells were observed to be receiving <br /> adequate vacuum, for compliance with the Title V permit and several were adjusted during this <br /> monitoring period. <br /> BACKGROUND <br /> As you know,the Forward/Austin Landfill site is an active organic refuse disposal site. By way <br /> of background, organic materials buried in a landfill decompose anaerobically(in the absence of <br /> oxygen)producing a combustible gas,which contains approximately 50 to 60 percent methane, <br /> 40 to 50 percent carbon dioxide, and trace amounts of various other gases, some of which are <br /> odorous. The Forward/Austin property contains a system to control the combustible gases <br /> generated in the landfill. <br /> The gases produced in a landfill will either vent vertically to the atmosphere or migrate <br /> horizontally through subsurface soil to locations on adjacent properties. If the soil surrounding a <br /> landfill consists of permeable materials,there is a greater likelihood that the LFG will migrate to <br /> off-site locations. <br /> UGELAEMU <br />