ARCHIVED REPORTS_2008_26 - Laserfiche WebLink

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An intermediate liner system is proposed over the existing Austin Road Landfill. Horizontal collectors, spaced at approximately 200 feet on center, will be installed to collect landfill gas generated below the liner (see Drawing 13 of the JTD). The horizontal collector consists of perforated HDPE pipe installed in a gravel pack below the proposed liner system. A geotextile fabric will be installed in the gravel trench to prevent fine materials from entering and clogging the collector pipe. Additionally, the existing vertical landfill gas wells will be cut about five feet below the liner and connected to the horizontal wells with laterals. The horizontal wells will be extended through the edge of the in-place refuse prism on the north face to extract landfill gas while the site is filled. When the refuse in adjacent waste cells reach the height of the horizontal well stub- outs on the south face, the horizontal well can be extended to collect the gas generated in the new cells. This end of the horizontal collector will be connected to the looped header system located along Austin Road's southern boundary. As the new cells are filled, additional vertical extraction wells will be installed, as necessary, in phases to control surface landfill gas emissions. These wells may JMkk be extended as the fill progresses in the cell, or may be abandoned and replaced with new wells when the fill reaches the final grade elevation. As the fill progresses above the existing and now-lined refuse prisms, additional vertical extraction wells will be placed, as necessary, into the upper portions of the landfill to achieve the proper spacing required for surface emissions control. Permits will be obtained from the San Joaquin Valley Air Pollution Control District (SJVAPCD) and other appropriate agencies for the construction and operation of the gas system. The LFGES will most likely be installed in phases as the landfill expands and/or as regulatorily required. As the landfill expands, it is anticipated that most of the system will be installed, with the balance of the system completed as part of closure. During closure construction, the system will be taken off line in phases as the final cover system is installed; the system will be modified, as necessary, and will then be reconnected. In order to integrate the gas control system with the final cover, the following procedures are proposed for closure construction. Forward Landfill PCPCMP 3-12 L:\Allied\2000.193\Reports\FinaIPCPCMP:FL-sec3.doc:5/21/02 BRYAN A.STIRRAT 6 ASSOCIATES