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Upon completion of the de-watering operation, the contained groundwater will be treated with <br /> granular activated carbon and discharged to the local sewer system. Prior to discharge, water <br /> t� s samples will be collected for analysis to confirm that treatment was effective. The rented water <br /> i storage tank will be cleaned at the site and the waste activated carbon will be transported off site <br /> for regeneration. 0-pz 1 j pyJ. )j-a�" , <br /> 3.5 Excavation Soil Sampling and Analysis <br /> During excavation, soil samples will be collected at various depths along the margins and central <br /> portions of the excavation. At an excavation depth of 10 feet bgs, 12 soil samples will be <br /> collected. Soil samples will be collected at each of the four corners of the excavation, every 15- <br /> feet along the excavation side-walls, and on 15-foot centers from the floor of the excavation. If <br /> possible, 12 additional soil samples will be collected from the same locations at 14-feet and 18- <br /> feet bgs. All of these deeper soil samples may not be retrievable due to the expected presence of <br /> groundwater in the excavation. Furthermore, the depth of sampling may be modified due to <br /> groundwater conditions observed during excavation. <br /> ti <br /> r� Soil samples will be collected in-situ or from the backhoe bucket, if inaccessible. Each of the <br /> \1 samples will be collected by hammering a brass sample sleeve into the soil with a rubber mallet. <br /> `L '7 The brass sleeves will be capped, labeled, packaged in an iced cooler and transported under <br /> chain-of-custody documentation to a state of California certified hazardous waste testing <br /> ')j�Haboratory for analysis. Each of the soil samples will be analyzed for TPH-as-diesel, TPH-as- <br /> " gasoline, BTEX and MTBE by Modified EPA Methods 8015 and 8020. <br /> 3.6 Site Restoration <br /> Once excavation and de-watering operations are complete, the excavation will be backfilled. The <br /> ��, deepest portions of the excavation will be filled with '/,-inch rock to bridge any standing <br /> �1 9 groundwater and stabilize any saturated soil. The excavation will then be backfilled with clean <br /> Dia soil. The backfill material will be placed to achieve a 90 percent compaction rate. Compaction <br /> lI/ testing will not be conducted. <br /> �1V i4 "'r+ <br /> t i uf4 Once the excavation has been backfilled, the shoring will be removed. The surface will be <br /> finished with a thin layer of aggregate base rock. No asphalt or concrete pavement will be <br /> / applied. <br /> top <br /> P <br /> 8 <br />