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Harding Lawson Associates <br /> VI IMPLEMENTATION OF THE SELECTED REMEDIAL ACTION <br /> A. Scope of Work <br /> The work will be approached as four tasks: <br /> Task 1 Install groundwater/soil-vapor extraction trench. <br /> Task 2 Trench to treatment compound and to tank pit area. <br /> Locate tank pit laterals and manifold all vapor <br /> ' laterals to a common manifold in the treatment <br /> compound. <br /> Task 3 Install soil vapor treatment system <br /> Task 4 Start-up and monitor the soil vapor treatment <br /> system <br /> ' 1. Task 1 - Install Soil Vapor/Groundwater Extraction <br /> Trench <br /> Extraction trench will be installed at the approximate <br /> location shown on Plate 7 . This trench will be constructed to <br /> Ifacilitate both groundwater and soil-vapor extraction. A vault <br /> box will be located at the western end of the trench in order to <br /> access the 4-inch groundwater extraction well for either pump <br /> installation or water sampling. The screen interval of the <br /> extraction well will be located at seven to ten feet below <br /> surface grade so that short circuiting of trench vapors does not <br /> occur through the well. <br /> ' Treatment of the excavated soils on site will reduce <br /> �j the levels of hydrocarbons in the soils so that they can be <br /> ■ transported to a Class III disposal facility. This can be <br /> ' accomplished two ways, active or passive aeration. Passive <br /> aeration involves the exposure of the soil to ambient air for <br /> 25 <br />