ARCHIVED REPORTS_2012_2 - Laserfiche WebLink

Home Browse Search

Additional infusion areas are constructed in Module 4 as needed to accept leachate. Normal Operation Leachate drains by gravity to the Module sumps from which it is pumped directly to the landfill refuse per the WDRs. The sump pump operates automatically, based on leachate levels within the sump. Operation of any Module sump pumps is conditional upon sufficient water in the sump (indicated by the level sensor on the pump) and available capacity in the associated leachate tank(indicated by the float switch in the tank). Control points for the pumps are: Control Action Indicated Depth Actual Depth inches (1) inches (1) Pump Off 50 53 Module 1 Pump On 45 48 High Level Alarm 2 10 13 Pump Off 80 83 Module 3 Pump On 75 78 High Level Alarm (2) 10 13 Pump Off 8 32 (3 Module 4 Pump On 18 42 High Level Alarm (2) 24 48 Note 1:"Indicated depth"is the reading of depth from the sensor located on the sump,approximately three inches above the pump (also see Note 3). Note 2:The high-level sump alarm is set to alarm at the upper lip of the leachate sump,thus alerting the operators before the one-foot leachate limit is exceeded at the Module floor beyond the sump. Note 3:The leachate pump intake of Module 4 is located 24 inches above the floor of the sump to avoid pulling soil from sump into the pump. In this semester, leachate from all three Modules was returned directly to the refuse of at approximately 160 ft NGVD, over approximately 120 feet of refuse compacted in multiple lifts. Data indicates that the leachate is being absorbed by the dryer refuse, and is not recirculating. Overwhelming of the LCRS system due to excessive recirculation is not indicated. Such indication would include the inability of a leachate sump pump to empty the sump. This condition was observed once, in 2003, when Module 4 was first installed. At that time, significant areas of that Module was lacking refuse, allowing rain water to quickly reach the LCRS without the opportunity to be absorbed by refuse. This situation was corrected by relocating the infusion of leachate to an area that contained more dry refuse. Overwhelming the capacity of the refuse to absorb leachate would be indicated by leachate seeps on the side of the fill in the vicinity of the infusion areas. This condition has not been observed. North County RC&SL Public Works/Solid Waste 1"Semester 2012 Groundwater Monitoring 11 County of San Joaquin—July 26,2012