COMPLIANCE INFO_JTD 9/3/2025 - Laserfiche WebLink

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Project No. AU25.1274 | PCPCMP Foothill Sanitary Landfill 7 September 2025 The first phase of an LFG control system was installed in 2006, which included nine vertical LFG wells and the flare station. This initial system has been expanded and currently consists of 39 vertical extraction wells and 17 horizontal collectors. Additional horizontal collectors and vertical wells will be added as the landfill is developed. The configuration and extent of the final landfill gas system is shown on Figure 6. It is assumed that all LFG system components are installed in projects prior to the closure project and that no construction costs for the LFG system will be incurred during closure. Costs for operation and maintenance of the LFG collection system in the post-closure maintenance period are included in post-closure maintenance costs. Landfill gas condensate generated by the LFG collection system will be handled as leachate in accordance with the Waste Discharge Requirements. 2.5.4 LFG Treatment Collected gas will be combusted as fuel for electrical generators or in one or more flare stations in accordance with the applicable SJVAPCD permits and regulations. LFG collected from the field is transported to the site’s landfill-gas-to-energy plant (operated by Ameresco Inc.) to generate power. The flare station is maintained as a back-up in the event the LFGTE plant becomes non-operational; in which case the LFG is burned in the flare in accordance with the Permit to Operate issued by the SJVAPCD. Presently, the LFG treatment equipment is located within the future landfill footprint. The treatment facilities will be moved in coordination with increasing the size of the facility to process increasing LFG. This movement is not part of closure construction, and is not included in the cost of closure. 2.5.5 Leachate Control Leachate from present and future modules will be collected in leachate collection and recovery systems installed with the modules (JTD Figure 18), and returned to lined modules in accordance with the Waste Discharge Requirements. As the landfill approaches closure, placement of the final cover and the overall thickness and absorptive capacity of the waste mass will cause less leachate to be generated. At this time, it is anticipated that leachate will be pumped from sumps using automatic, level sensing pumps and discharged through flow meters to onsite temporary storage or returned to lined landfill modules in accordance with the WDRs. It is also anticipated that the absorption capacity of the relatively dry refuse placed at the FSL, and the uptake of water in the production of landfill gas, will allow for the return of leachate over the lined modules for many years after closure. Inadequacy of those mechanisms, if it occurs, would be indicated by the inability of the leachate pumps to remove leachate from the leachate sumps to maintain less than 1 foot of liquid head over the liner. Monitoring of the leachate pumps and sumps will indicate that this condition is developing. If this occurs, leachate g enerated after