CORRESPONDENCE_2010-2015 - Laserfiche WebLink

Home Browse Search

Environmental Consultants 4730 Enterprise Way 209 545-8490 and Contractors Suite A FAX 209 545-8391 Modesto, CA 95356 www.scsengineers.com June 21, 2012 File No. 07207049.00 Mr. Don Litchfield Forward Landfill 9999 South Austin Road Manteca, California 95335 Subject: Second Quarter 2012, 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 second quarter of 2012 (April through June) 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. 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. Also, during this reporting period, SCS performed testing of Temporary Subsurface Evaluation Monitoring Probe Nos. TGP-01 through TGP-39. Results of this testing indicated that up to 58.7% methane gas was detected at several of these monitoring locations. Note that these locations are for evaluation purposes only and are not compliance locations. Finally, during this reporting period, SCS performed monitoring of probes GP Nos. 7 (D, M, S) through GP-12 (D, M, S). These locations were replaced during the recently approved monitoring network expansion as authorized by the San Joaquin County Local Enforcement Agency and Cal Recycle. See data in Table 1 (Subsurface Evaluation Points). Note that these locations are for evaluation purposes only and are not compliance locations.