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K '1 r Specificgtion R91QZ5-01 ^' 4.12 Pilot test duration would be approximately one week or until four carbon canisters have been exhausted,whichever occurs first. Approximately one week would be required to get up the pilot .test system. If carbon is exhausted within a few days, data would be evaluated. This pilot test Work Plan would be revised as necessavy, including evaluation of alternative air pollution control technology. 5.0ir_I xri nW 11 n ' 5.1 Design of a soil treatment cell, extending from site surface to the water table approximately seventy feet (70') below grade, would be based on results of the Pilot Test. Figure B-1 presents a schematic diagram of a typical vapor well which T would be installed for both extraction and passive air injection. Design of the well field would be based on the results of the pilot test and evaluation of the lateral and vertical extent of soil contamination. Construction of the well field could proceed subsequent to the pilot test and concurrently With the assessment investigation (i.e. from the soil borings drilled for installation of the wells and manometer points). 5.2 Configuration of Vad%g ZQUe Air Wells Vadose zone air wells would be installed, if necessary, and constructed to mWmize distances between passive injection and extraction points. Minimization of air travel distance increases control of airflow rates and vacuums and, consequently, remediation process control and predictability. To promote air flow through the treatment cell,air intake and extraction points wc,uld be stratifed as follows. Strata 1 15' to 45' Strata 2 45' to 75' (approximate depth of water table) 5.3 W H Construction At each air-well location, two eight-inch diameter boreholes would be drilled adjacent to one another. It is anticipated that one well would be installed to a depth of app►oximately 63 feet and the second well to a depth of approximately 30 feet. For a maximum well depth, the borehole would be advanced from the soil surface to the lower unit of air release or withdrawal(at about 65 feet below grade of the water table capillary fringe). Vadose wells would end above the aquifer free water surface to minimize the yield of free art-1 condensate water mixed systems. After completion of the borehole to its final depth,the borehole would be partially backfilled with a natural well packing material (sand, pea stone, gravel, etc.) to be selected after site soil evaluation. The lower vertical air conduit would be placed on the backfill v-Ath its upper end approximaisly two feet above grade(until shortened during air conduits network. construction). Additional well packing would be added until the packing reaches B-5 REMEDIATION SERVICEA. INC. �b