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4.4.2.3 Holes and Trenches <br />Vertical bore holes or horizontal trenches constructed for LFG collection elements will be <br />of sufficient cross-section to allow for their proper construction and completion, <br />including centering of pipes and placement of gravel backfill. The holes and trenches <br />will be constructed under supervision of a construction quality assurance program <br />implemented by the County. <br />4.4.2.4 Component Short Circuiting <br />LFG collection elements will be designed to prevent air infiltration through the cover, <br />refuse contamination of the collection elements, and direct venting of LFG to the <br />atmosphere. Air intrusion control will be verified through monitoring extracted LFG for <br />oxygen and notrogen. Contamination of the collection elements by the refuse will be <br />prevented by placing gravel filter pack between the refuse and the LFG collection <br />elements. Direct venting of the LFG to the atmosphere will be avoided by operating the <br />GCCS under vacuum. Thus, any leaks will result in air entering the GCCS, as opposed to <br />L110 being released into the AMOsphere. <br />4.4.2.5 Gravel Backfill <br />Gravel of sufficient size will be used to prevent penetration or blockages of the LFG <br />collector pipe perforations. The nominal gravel size will be between 1 and 2 -inch <br />diameter. <br />4.4.3 Landfill Gas Extraction Component Connections to LFG Transmission <br />Piping <br />§60.759(b)(3) Collection devices may be connected to the collection <br />header pipes below or above the landfill surface. The connector <br />assembly shall include a positive closing throttle valve, any necessary <br />seals and couplings, access couplings and at least one sampling port. <br />The collection devices shall be constructed of PICC, HDPE, fiberglass, <br />stainless steel, or other nonporous material of suitable thickness. <br />In general, the collection devices will be connected to the collection header pipes via <br />lateral piping. The lateral piping will be connected to the header above the landfill <br />surface. The connector assemblies will be located above grade. These assemblies <br />include positive closing throttle valves, necessary seals and couplings, access couplings, <br />and a sampling port. The collection devices will be constructed of PVC, HDPE, <br />fiberglass, stainless steel, and other nonporous material of suitable thickness or carbon <br />steel with an adequate corrosion allowance. The GCCS components will be designed and <br />installed to withstand installation, static, and settlement forces; and withstand planned <br />overburden or traffic loads. <br />Foothill Sanitary Landfill 14 Public Works/Solid Waste <br />LFG CS Design Plan County of San Joaquin - March 10, 2005 <br />