COMPLIANCE INFO_JTD 9/3/2025 - Laserfiche WebLink

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Foothill Sanitary Landfill 24 Department of Public Works/Solid Waste First Semiannual 2025 Groundwater Monitoring ©2025 County of San Joaquin. All rights reserved. Pump Control Area 1- Sump Area 2A- Sump Area 2B- Sump Pump Off 17” 12” 10” Pump On 36” 30” 36” Alarm 48” 42” 42” Operation of the pump is conditional upon sufficient water in the sump and available capacity in the leachate tank. A high-level alarm is activated if the leachate exceeds the alarm level. The alarm level is chosen to maintain the hydraulic head on the Area base below the maximum allowed of 12 inches. The leachate storage tank facility includes secondary containment (consisting of a concrete vault surrounding the tank) and a truck loading area. Controls for the leachate storage tank include a high-level sensor that will sound an alarm and disable the leachate sump pump if the level in the tank nears the top of the tank. This prevents overtopping of the tank. However, the secondary containment will retain any leachate in case of failure of those controls. 12.3 LFG Condensate Due to the designation of portions of the Foothill Sanitary Landfill as separate Waste Management Units (WMUs), and due to the prohibition in the CFR against transfer of landfill gas condensate from one WMU to another WMU, condensate collected from Module “I” should not be returned to the refuse of other Modules. With the completion of the recent LFG collection system expansion, condensate from both sites is now collected in two sumps at the flare station. Condensate from Module “I” is pumped into Tank 3 and either comingled and processed with leachate or will be incinerated by the flare. LFG condensate from the other Modules is comingled with Leachate and either reinjected into a lined module, or sprayed on the surface to maximize evaporation. 12.4 Leachate System Monitoring and Maintenance The flow rate provided by the sump pump is recorded at least monthly. If the pumping rate from the sump pump is observed to be decreasing, troubleshooting and maintenance will be done on the pumping equipment as needed to return pumping operations to normal conditions. Leachate production is greater in the late winter and spring, compared to summer and autumn, because little to no rain falls on the site from April to November of each year. The secondary leachate sump is monitored monthly. The pump, permanently installed in the secondary sump under Module 1, is operated automatically. The pump operates until the leachate level drops below the pump activation level. A totalizer records the gallons removed by this pump.