Laserfiche WebLink
landfills in southern California. It can reasonably be concluded therefore, that the level of <br />contamination and health risks from leachate will decrease over time at the Forward <br />Landfill. <br />Interim Cover — Placement of appropriate interim cover over a solid waste site establishes <br />an environment where infiltration is minimized and, as a result, leachate volume declines. <br />Since any reduction in leachate generation rates will decrease the risk of leakage and <br />resultant environmental impacts, Forward is proposing to place interim cover specifically <br />designed to minimize infiltration. This will include placement of one foot of low <br />permeability soils on slopes of 3:1 or greater and phased final closure of the top deck in <br />ten acre increments as final grades are reached. The effectiveness of the interim cover <br />installation process will be enhanced by the fact that a majority of the site will be sloped <br />to accelerate run-off. In addition, the interim cover will be hydroseeded every year in <br />order to maximize evapotranspiration. <br />Landfill Gas Management - Local, state and federal regulations require the installation of <br />a landfill gas extraction system (LFGES) to collect and control landfill gas and prevent it <br />from migrating beyond the landfill boundaries, accumulating in off-site structures, and to <br />prevent the emission of HAPS into the atmosphere. An active landfill gas extraction <br />system (LFGES) has been installed on a portion of the existing Austin Road Landfill. <br />This LFGES is currently being expanded with additional gas collection wells and a gas - <br />flare system to better control landfill gas in the area. Additional gs control systems are <br />also being installed within WMU-B at the Forward Landfill as a proactive measure to <br />better control landfill gas and minimize the potential for groundwater impacts in this area. <br />The existing Forward Landfill is not currently required to have a LFGES but one will be <br />designed, installed and operated for the combined landfills, when necessary, to achieve <br />compliance with 27 CCR and 40 CFR or earlier if deemed necessary for groundwater <br />protection. <br />Because landfill gas collection system maintenance is key to its effective operation <br />and its public health and environmental protection, routine maintenance of the system <br />will be conducted throughout the life of the landfill and following landfill closure <br />throughout the post -closure maintenance period. As the landfill settles, the gas header <br />pipes, which are placed on the surface of the landfill can be inspected and adjusted <br />and/or repaired as necessary to maintain the effectiveness of the system. The vertical <br />extraction and horizontal collectors will be connected to a looped LFGES that will be <br />installed around the perimeter of the landfill. The looped gas header system will allow <br />for the shut -down of only a very small portion of the extraction system while <br />maintenance is being performed, minimizing the potential impact of surface emissions <br />and subsurface landfill gas migration. <br />Gas Condensate Collection - As landfill gas cools within LFGES piping, condensate is <br />formed. A condensate management system will be designed to handle condensate that <br />collects in the low points of the LFGES piping. Sump pump stations will be utilized to <br />transfer condensate from these low points to a holding tank located at the flare station. <br />510 <br />CA2000-048\Fomord Composite Liner V3 .doe\09/19/02 <br />Geologic Associates <br />