Laserfiche WebLink
buried horizontal gas collector, and below grade laterals connected to a <br /> series of vertical gas extraction wells. All LFG collected from this system is <br /> routed to LFG-to-energy power plant owned and operated by Covanta <br /> Energy. Landfill gas not utilized by the power generation facility will be <br /> collected, conveyed and incinerated at the flare station. The flare station <br /> location is identified on Figure 3. <br /> A portion of the Covanta Energy LFG extraction system will be taken off-line <br /> to allow for grading activities. To keep the power plant operational, <br /> temporary laterals from the primary LFGES system will be routed to the <br /> Covanta Energy header to supplement their fuel requirements. Once the <br /> Covanta LFG extraction system is re-installed, the temporary laterals will be <br /> removed or abandoned in-place. <br /> In order to integrate the gas control system in the Stage IA partial closure <br /> area with the final cover, the following procedures are proposed for closure <br /> construction. <br /> Prior to placement of the final cover, the header system will be removed in <br /> phases, as shown in the gas system Drawing Sheets G-1 through G-14, to <br /> minimize interruption of the gas system operation. The gas header, <br /> compressed air, and condensate conveyance lines will be re-installed and <br /> made operational prior to removal of the next phase. Any affected wells will <br /> be disconnected prior to removal of the header. Headers will be re-installed if <br /> the integrity of the pipe remains intact and if it can be adjusted to a positive <br /> grade. Otherwise, the pipelines will be replaced. The main header system <br /> will remain on-line during the entire construction period. <br /> All vertical gas collection wells in place in the Stage IA partial closure area will <br /> be protected during the placement of the final cover since control of landfill <br /> gas will continue during cover construction. The top of the vertical wells or <br /> well laterals will be extended through the final cover and then reconnected to <br /> the perimeter header system line as before. Any damaged or non-functional <br /> vertical wells or laterals will be abandoned and new replacements installed to <br /> provide gas extraction coverage. Final cover material will be placed and <br /> compacted by hand around the wells or vaults to protect against damage by <br /> earthmoving equipment. In order to keep the gas system operational during <br /> Forward Landfill PFCPCMP 3-15 <br /> Z:\PROJECTS\Allied Waste\Forward\Reference Files Prior JTD\June 05 Stage IA Partial FCPCMP\FL-sec3.doc:6/16/2008 <br />