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0 3.7 FRENCH DRAIN •,UID 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 />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 />Z:\PROJECTS\Allied Waste\Forward\Reference Files Prior JTD\June 05 Stage IA Partial FCPCMP\FL-sec3.doc: 6/16/2008 <br />