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WASTE DISCHARGE REQUIREMENTS ORDER NO. R5-2010-0016 -10- SAN JOAQUIN COUNTY DEPARTMENT OF PUBLIC WORKS NORTH COUNTY LANDFILL SAN JOAQUIN COUNTY <br /> <br /> Leachate and Condensate Management 42. Since 2002, the discharger has been pumping collected landfill leachate and LFG condensate back to the landfill, subject to approvals in previous WDRs, which incorporated liquids restrictions in Title 27 and Subtitle D regulations. In the Second Half 2008, approximately 124,000 gallons of leachate (including LFG condensate) were pumped from and returned to the landfill. <br />43. As described in the JTD, LFG condensate is pumped into the LCRS and handled like leachate. Leachate is pumped from the landfill sumps and/or AGTs to dedicated infusion points on the upper elevations of the compositely lined landfill Modules. No liquid is returned to Module 1, however, since it does not comply with Subtitle D. These WDRs allow the Discharger to continue returning landfill leachate and condensate to the landfill, provided that compliance with the applicable liquids restrictions is maintained. See Discharge Prohibition A.3 and Discharge Specification B.4. <br />LANDFILL DESIGN AND CONSTRUCTION <br />Existing Modules <br />Module 1 44. Module 1 (referred to as Modules 1 and 2 in previous WDRs) was constructed in 1991 with a non-prescriptive, non-composite containment system, as follows: <br />Component Base Liner Side Slopes Operations Layer ≥ 2’ soil Filter Fabric Geotextile1 LCRS Geonet -------2 <br />Base Liner 60-mil HDPE3 Foundation Layer ≥ 6” compacted soil ____________________________ 1. 10 oz/yd2 non-woven fabric. 2. No LCRS on side slopes. 3. HDPE smooth on both sides. <br />The module predated Subtitle D regulations and was therefore not required to have a Subtitle D composite liner (see Finding 5). Further, previous WDRs (Order No. 91-021) included a finding that natural geologic factors at the site (e.g., groundwater separation, soil type) were sufficiently protective of groundwater such that a Chapter 15 containment system was not required (see Title 27, Section 20260). Although not required under regulation, a 60-mil HDPE base liner and geonet LCRS were included in the design for additional protection.