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Environmental Consultants 4707 Greenleaf Circle 209 545-8490 Suite F Fax 209 545-8391 Modesto, CA 95356 www.scsengineers-com February 15, 2006 File No. 07202055.00 pc Ms. Christina Carbajal 2 2006 Forward Landfill 9999 S. Austin Road E IN V 1 R 0 NrNAE i,,'i Manteca, California 95336 P E RM IT/: E R V `E_S Subject: Operation, Monitoring, and Maintenance of the Landfill Gas (LFG) Migration Control Facilities at the Forward/Austin Landfill, Manteca, California Dear Mr. Caffey: This letter provides a status report on the operation, monitoring, and maintenance (O&M) work performed by SCS Field Services (SCS) on the subject-system. All activities were performed in accordance with ry -our approved contract work scope dated February 14, 2003. Below is a summa of I O&M efforts fforts-during the period od of January 11 1 througli 31, 2006. Conclusions and Recommendations As of the dates of our testing, the LFG control facilities appeared to be operating satisfactorily and generally meeting the operational erational criteria with the exception of elevated methane gas concentrations detected at Perimeter Monitoring Probe Nos. GP-9, GP-11 and GP-12 (up to 53.8 percent by volume). Also, on January 5 and 12, 2006, SCS performed monitoring of Temporary Gas Probes, defined as TGP-01 through TGP-39, as directed by the Client. Results of this monitoring indicated that methane gas concentrations in excess of the LEL were detected at several locations tested (up to 60.1 percent by volume). Note, that these probes are intended for evaluation purposes only and are not compliance locations. All LFG extraction wells were observed to be receiving adequate vacuum and several were adjusted during this monitoring period. Recommendations regarding repair or maintenance activities may be contained in subsequent sections of this report. Please advise SCS as soon as possible regarding implementation of these recommendations. Background As you know, the Forward/Austin Landfill site is an active organic refuse disposal site. By way of background, organic materials buried in a landfill decompose anaerobically (in the absence of oxygen) producing a combustible gas, which contains approximately 50 to 60 percent methane, 40 to 50 percent carbon dioxide, and trace amounts of various other gases, some of which are odorous. The Forward/Austin property contains a system to control the combustible gases generated in the landfill.