Laserfiche WebLink
41 0 <br />the prime cause of contamination to be LFG from the discovered refuse. The new <br />LFG wells will be installed to collect LFG from the discovered refuse and will <br />provide better extraction of LFG, thus reducing the VOC impact on the ground <br />water. The Regional Water Quality Control Board has approved the installation of <br />the new LFG wells as corrective action to mitigate the impact to ground water. <br />The contractor will be required to comply with this work plan and construct new <br />LFG wells per the construction drawings and specifications. <br />2.1 WELL LOCATION <br />The new LFG wells will be installed near the northern property boundary of CHSL <br />(Figure 2). <br />2.2 DRILLING <br />Solid Waste Division (SWD) will obtain drilling permits from San Joaquin County <br />Environmental Health Department (EHD). The wells will be drilled by a licensed <br />contractor. A boring log will be compiled during drilling by the contractor using a <br />form provided by SWD (Appendix A). <br />The wells will be drilled into the refuse outside the existing closure cap to the <br />depths specified in the well schedule (Figure 5). Depths of all wells will be above <br />seasonal ground water table. Drilling of the new wells will include excavation of <br />refuse and minor contact with refuse. Excavated refuse and soil with refuse and <br />construction debris will be placed in a bin and disposed off-site. <br />Abondoned borings will be backfilled with clean soil, compacted in two -foot lifts, up, <br />to four feet below grade. A bentonite seal, four inches thick, will be placed in the <br />borehole four feet from the surface. The borehole will then be capped with <br />compacted clean soil. <br />2.3 WELL CONSTRUCTION <br />It is anticipated the new wells will be constructed immediately after drilling. <br />A. Well Laterals <br />The new wells will be connected to the existing landfill gas system with a 4" HDPE <br />lateral pipe (Figure 2 and 3). The well lateral pipes will be installed across the <br />access road under and through the barrier layer at the foot of the slope. The well <br />Work Plan — LFG Extraction Well Installation <br />Corral Hollow Sanitary Landfill <br />10-2-08 <br />2 <br />San Joaquin County <br />Public Works Department <br />Solid Waste Division <br />