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excavation activities or performed daily as the soil is removed. In either case field screening will <br /> be performed to assist in the efficient removal of contaminated soil in all directions to the <br /> ' maximum degree possible during the excavation activities. <br /> Tasks 2.1.5 <br /> The excavation will be backfilled in engineered lifts. The initial material installed in the open <br /> excavation will be a 1.5 to 2 inch crushed rock. The crushed rock will be placed throughout the <br /> entire bottom of the pit up to approximately one foot above the water table. Then a Class 2 base <br /> ' rock will be placed into the excavation where this new material will be leveled off, rolled and <br /> compacted into place. The base rock will be used to fill the excavation up to within 4 inches of <br /> surface grade. At this time the entire area of the excavation and the immediate area surrounding <br /> ' the excavation will be asphalted with a 4-inch cap. This final task will seal off the subsurface <br /> from any storm water percolating down and spreading residual contamination. <br /> Tasks 2.1.6 <br /> Upon completing the profiling of the contaminated stockpile we will contact both Forward <br /> Landfill and Vasco Road Landfill for bid proposals. Since both facilities are Class II units and <br /> the transportation relatively the same the soil will go to the lowest bidder. The contaminated soil <br /> would then be loaded into 18 cubic yard end dump semi-trucks and transported to one of these <br /> ' faculties. Each truck leaving the site will have a separate bill of lading with a controlled waste <br /> manifest. <br /> ' Tasks 2.1.7 <br /> When the contaminated soils have been removed and the site is cleaned up, a full remedial <br /> t excavation summary report with all supporting documentation will be generated. This report <br /> will detail the extent of the excavation, field observations of the soil, water table and any other <br /> items of interest. <br /> ' Option tasks 2.1.8 <br /> As previously mentioned and if the conditions warrant it, we have on occasions installed a <br /> horizontal grid of PVC piping into the bottom of the excavation prior to back filling. The piping <br /> ' is placed below the water table and then the larger 1.5" rock is gently placed over the top. When <br /> completed this subsurface aeration grid can be attached to a positive displacement blower on the <br /> surface. The influence of having a large screened area laid out horizontally throughout the <br /> ' excavation can greatly increase the subsurface oxygen content in tum stimulating bacteria colony <br /> growth. There is no comparison of the area of influence versus vertical sparge wells to <br /> oxygenate the subsurface. This is an excellent and very economical way to complete this task if <br /> ' it is warranted. <br /> ' DEL-TECH Page 8/15/00 <br />