ARCHIVED REPORTS_2011_3 - Laserfiche WebLink

Home Browse Search

Leachate System Monitoring and Maintenance The flow rate provided by the sump pump is tested at least monthly. If no other causes are apparent, a decrease in pumping rate will indicate the need to clean a filter or to investigate pump wear. Leachate production rate is greater in the late winter and spring, compared to summer and autumn,because little or no rain falls on the site from April to November of each year. The secondary leachate sump is monitored monthly for the presence of LFG condensate. If possible,this condensate is removed, and if removed,the volume is recorded. Landfill Gas Condensate Removal from Module 1 Secondary S11M Removal of liquid from the secondary sump was automated in October 2011. A pump within the secondary sump is operated three times weekly. The depth of liquid in the secondary sump is also monitored monthly using by a bubbler tube installed into the sump. Measurements indicate that the pump is maintaining the liquid level at the minimum level that allows the pump to remove liquid. ANNUAL SUMMARY Groundwater General Water Quality Parameters MW-4 was located directly up-gradient of the landfill based on groundwater elevations from the previously- installed wells. This well has been sampled eleven times since installation. Concentration limits have been established based on Sanitas software calculations using data for MW-4. The following annual compliance review was prepared for each well: • Well MW-l:No General water quality parameters were exceeded during either the 1St or 2nd semester 2011 sampling events. • Well MW-2R: Nitrate was recorded at 2.8 mg/L in the first semester,which slightly exceeded the tolerance limit of 1.8 mg/L, but was not confirmed in the second semester monitoring event. No other general water quality parameters were exceeded in this well during either the 1St or 2" semester 2011 sampling events. • Well MW-3: Nitrate was recorded at 2.8 mg/L in the first semester which slightly exceeded the tolerance limit of 1.8 mg/L but was not confirmed in the second semester monitoring event.No other general water quality parameters were exceeded in this well during either the 1St or 2nd semester 2011 sampling events. • Well MW-4: No General water quality parameters were exceeded during either the 1St or 2nd semester 2011 sampling events. • Well MW-5: No General water quality parameters were exceeded during either the 1 St or 2nd semester 2011 sampling events. Foothill Sanitary Landfill 11 Department of Public Works/Solid Waste 2"d Semester and Annual 2011 Groundwater Monitoring County of San Joaquin—January 31,2012