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r r R i Environmental Consultants 4707 Greenleaf Circle 209 545-8490 and Contractors Suite F FAX 209 545-8391 Modesto,CA 95356 www.scsengineers.com April 1, 2011 File No. 07207049.00 RECEIVED APR 0 8 2011 Mr. Don Litchfield Forward Landfill ENVIRONkIENTAL HEALTH 9999 South Austin Road PERIANT/SERVICES Manteca, California 95335 Subject: First Quarter 2011, Perimeter Landfill Gas (LFG)Monitoring Probe and On-Site Structure Testing at the Forward Landfill, Manteca, California Dear Mr. Litchfield: This letter provides results of gas monitoring probes (GMP) and on-site structure testing for the first quarter of 2011 (January through March)performed by SCS Field Services (SCS). All testing,monitoring protocols and reporting were performed in general conformance with Title 27 California Code of Regulations (CCR)Article 6. Briefly, these regulations require that solid waste disposal site owners/operators implement LFG control or monitoring provisions to ensure that methane gas concentrations in soils at the property boundary do not exceed the lower explosive limit(LEL, or 5 percent by volume) and that interiors of on-site structures do not exceed 1.25 percent by volume in air. Below is a summary of our quarterly monitoring activities. SUMMARY AND CONCLUSIONS During this reporting period, no methane gas (the combustible component of LFG) in excess of the LEL was detected at any perimeter subsurface compliance GP probe location tested or in excess of 1.25 percent by volume in air at any interior locations or on-site structures, with the exceptions of LFG Monitoring Probe Nos. GP-09M, GP-09S, GP-11M and GP-12S (up to 13.0% by volume). During March 2011, monitoring probes GP-I IM and GP-12S returned to regulatory compliance (below 5.0%by volume). During this reporting period, GP Probe Nos. GP-09M and GP-09S, were in compliance until March 31, 2011,when methane concentrations exceeded the compliance level of 5%by volume. On April 1, 2011, SCS performed adjustments and modifications to the collection system, and by April 2, 2011, methane gas concentrations at the probe had decreased to below the LEL. SCS will continue to monitor these locations and adjust the wells in the surrounding area to bring the monitoring probes below regulatory compliance levels. These results indicate that at the time of our testing the subject site perimeter subsurface GP probes and interiors of on-site structures are in compliance with requirements of Title 27 CCR, with the exceptions noted above. SCS understands that theP robe network is under review by the CIWMB to enable relocation of the probes to the property boundary. L ¢ 4 E e R P H t• j4ARS YE