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Water Quality Monitoring Report Forward Landfill 1.5 Landfill Gas Monitoring In accordance with Title 27 California Code of Regulations (27CCR), Article 6, SCS Field Services (SCS) conducts quarterly monitoring of perimeter gas probes and on-site structures at the Forward Landfill. During the fourth quarter 2016 monitoring period, no methane gas exceeded the regulatory limit of five percent by volume in perimeter gas probes and no methane was detected in on-site structures. As part of the CAP, Forward operates a landfill gas (LFG) extraction system to control LFG emissions (i.e. source control). SCS performs the operations and maintenance (0&M) for the LFG extraction system and blower/flare station (BFS). Summary tables for the BFS and LFG extraction wells, and the fourth quarter 2016 perimeter LFG monitoring probe and on-site structure testing report are presented in Appendix B. During the fourth quarter 2016 monitoring period SCS reported 34.7 hours of downtime for the BFS. Based on the BFS data and 2016 Annual Compliance Emissions Test Report prepared by Blue Sky Environmental, Inc., the LFG extraction system removed approximately 33,899 pounds of VOCs for the fourth quarter 2016. A summary of the LFG and destruction system operations and maintenance for the fourth quarter 2016 are presented in Appendix C. SCS performed field sampling of 208 LFG extraction wells between December 13 and 30, 2016 for VOCs using US EPA Test Method TO -15. The LFG samples were delivered under chain of custody protocol by courier to Eurofins Air Toxics, Inc. of Folsom, California. The analytical results of LFG analyses are presented in Appendix F. Tabulated analytical results for the second semiannual 2016 are presented in Appendix B. At municipal solid waste (MSW) landfills, such as Forward Landfill, MSW is heterogeneous, and therefore, patterns of LFG compounds and their concentrations can vary within the landfill. Typically MSW LFG composition consists of methane, carbon dioxide, oxygen, nitrogen, and non -methane organic compound (NMOC) concentrations. The NMOL concentrations in LFG are a function of the types and age of waste in the landfill and the extent of the reactions that produce various compounds from the anaerobic decomposition of waste. As demonstrated by the results of the TO -15 testing, the NMOC concentrations in LFG vary across the landfill from well to well with no distinct pattern. This is consistent with the expectations for the heterogeneous environment of an MSW landfill. The second semiannual 2016 TO -15 sampling event demonstrated that NMOCs were present in the LFG extraction wells, consistent with expectations for an MSW landfill. In the event of an uncontrolled release, there is the potential for LFG to impact the unsaturated zone; however, LFG probes have been installed in accordance with Title 27 of the California Code of Regulations and demonstrate continued compliance with the requirements. In addition, the combined LFG collection system, the Ameresco landfill gas -to -energy plant, and the Forward LFG flaring system, are operating at 91% of full capacity and in compliance with regulations. The LFG collection and combustion system is upgraded on a routine basis to optimize LFG collection. The potential for LFG impacts on the unsaturated zone are therefore being mitigated through source control measures. If it is determined that additional mitigation is needed, or if impacts Project No. 2016.0007 1 Water Quality Monitoring Report 4 January 2017