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3.7 FRENCH DRAIN LIQUID SEEP COLLECTORS <br /> French Drain Liquid Seep Collectors will be placed in the areas shown on <br /> Drawing Sheet 8. The collectors will consist of a geonet drain placed along <br /> the slope in the area of the seep. As shown in Detail 2 of Drawing Sheet D-3, <br /> approximately 3 feet of final cover soil will be placed on top of the geonet <br /> drain. The geonet will direct liquids by gravity flow to a gravel drain at the toe <br /> of the slope. The gravel drain will be wrapped in a geotextile and may be <br /> underlain by a Flexible Membrane Liner (FML) which would extend <br /> approximately 24 inches up the slope (FML optional). A three-inch perforated <br /> high-density polyethylene (HDPE) pipe will be placed in the gravel drain and <br /> will direct liquids to a holding tank down gradient of the seep. Liquids <br /> collected in holding tanks will be treated as leachate and handled consistent <br /> with current procedures. <br /> 3.8 LANDFILL GAS CONTROL <br /> The purpose of the landfill gas recovery and monitoring system during <br /> closure and post-closure is to protect public health and the environment. The <br /> Forward Landfill gas control and monitoring system will be installed and <br /> operated in accordance with 27 CCR, Section 20920 and 40 CFR, Subpart <br /> WWW. <br /> The primary LFG extraction system in the closure area consists of seventy- <br /> four (74) vertical gas extraction wells and a LFG flare station. This system <br /> was installed in 2001 in the northern section of the landfill (formerly Austin <br /> Road Landfill). These wells were installed below an intermediate soil liner on <br /> the top deck of the landfill and are connected to a perimeter gas header <br /> system along the northern and western boundary of the landfill. The well <br /> laterals are grouped together and routed to well manifolds around the <br /> perimeter. These wells will be utilized to control LFG emissions in the Stage <br /> IA partial closure area. No additional gas extraction wells are proposed for <br /> the Stage IA partial closure area. <br /> A second LFG extraction system, independent of the system described <br /> above, is also currently in operation in the Stage IA partial closure area. This <br /> system consists of twelve (12) above grade vertical gas extractions wells, one <br /> Forward Landfill PFCPCMP 3-14 <br /> ZAPROJECTS\Allied Waste\Forward\Reference Files Prior JTD\June 05 Stage IA Partial FCPCMP\FL-sec3.doc:6/16/2008 <br />