Laserfiche WebLink
<br />Preliminary Closure and Postclosure Maintenance Plan 2-7 Department of Public Works/Solid Waste <br />North County Recycling Center and Sanitary Landfill County of San Joaquin <br /> <br />slope stability cross-sections for Areas 4 through 11 also showed adequate static factors of <br />safety. <br />The results for the static slope stability of the most critical interim waste slope within Areas 5 <br />through 11 yielded an acceptable static factor of safety if each future liner system design and <br />construction satisfies specified shear strength values (Appendix C). <br />The results of the slope stability analysis indicate the existing and planned slopes meet the <br />acceptance criteria of CCR Title 27. <br />2.5.6 Landfill Gas (LFG) Migration Monitoring <br />Title 27 CCR (20921) requires that owners or operators of all municipal solid waste landfill units <br />implement routine LFG migration monitoring programs to ensure that concentrations of methane <br />do not reach the lower explosive limit (LEL = 5% methane by volume in air) at the facility <br />monitoring perimeter or exceed 25 percent of the LEL in facility structures. To comply with this <br />regulation, the County has installed 18 monitoring wells at maximum 1,000-foot centers along a <br />monitoring perimeter (Figure 3 and JTD Plate 6), and monitors on-site structures within the <br />perimeter. These wells will continue to be monitored and maintained in the postclosure period <br />per the Gas Monitoring and Control Plan (JTD Appendix I). On-site structures, if any, will also <br />be monitored. <br />Analysis of samples from the perimeter migration monitoring network for VOC concentration <br />may be required by regulatory agencies. <br />2.5.7 LFG Emission Control <br />LFG emissions will be controlled by an active LFG collection system. The first portion of this <br />system was installed in 2006, and will be extended into the landfill as the landfill is developed <br />such that little additional construction is anticipated at closure; however, a portion of the system <br />will be reconstructed at closure. LFG condensate will continue to be delivered to the LCRS <br />system and returned to the landfill with leachate in accordance with the current WDRs. <br />Treatment of the collected gas may be by combustion in a flare (as it is today) or by utilization <br />as fuel in a landfill-gas-to-energy facility. The closure cost estimate assumes combustion in a <br />flare relocated to the south-west corner of the property sometime before closure. <br />Projected costs for operations and maintenance of an LFG collection and control system are <br />included in the postclosure maintenance cost estimate. <br />2.5.8 Groundwater, Surface Water, NPDES, and Unsaturated Zone Monitoring <br />Groundwater <br />Water quality is monitored consistent with the current WDRs (JTD Appendix A). The <br />groundwater monitoring network presently consists of 13 groundwater monitoring wells <br />(Figure 3 and JTD Plate14).