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gravel pack, and the remaining annulus backfilled with neat cement containing <5% bentonite <br /> powder The wellhead will be designed and completed in a manner similar to that of the <br /> monitoring wells The location for this proposed vapor extraction test well is shown on Figure <br /> 3 <br /> Vapor Extraction Pilot Test <br /> A soil vapor extraction pilot test will be conducted to assess the suitability of subsurface soil <br /> conditions for soil vapor extraction as a possible option for site remediation The pilot test data <br /> will provide necessary design criteria including optimal vapor recovery rates, vapor destruction <br /> efficiency, and the effective radius of Influence A vacuum blower equipped with a vacuum <br /> meter and anemometer combined with independent soil vapor probes will be used to perform the <br /> test <br /> The onsite vapor extraction well will be connected to the system to establish vapor pressure and <br /> flow rates at variable vacuum pressures Pressure changes in surrounding vapor probes will be <br /> recorded once conditions stabilize An estimation of the effective radius of influence can be <br /> obtained by plotting radial pressure distribution equations Organic vapor concentrations will be <br /> monitored throughout the pilot test Initial contaminant removal rates can be estimated from <br /> measured flow rates and laboratory analytical results from samples collected during the pilot test <br /> A total of three vapor samples will be collected for laboratory testing Destruction efficiency can <br /> be calculated by comparing laboratory analyses of inlet and exhaust vapor samples collected <br /> . simultaneously during the test <br /> Aquifer Pump Test <br /> An aquifer pump test will be performed to evaluate the hydraulic conductivity of the aquifer, <br /> groundwater flow and recharge rates, and the effective zone of capture This data will be used <br /> to assess the potential effectiveness of a groundwater pump and treat system to address <br /> groundwater contamination Groundwater will be withdrawn from the existing 4-in monitoring <br /> well using a submersible electric pump Groundwater depths well be monitored in the 4-in well <br /> and the surrounding monitoring wells using a data logger and four independent transducers The <br /> well will be pumped at a constant rate of 1 to 3 gal/hr for a duration of 6 to 8 hrs, drawdown <br /> will be recorded in the newly installed monitoring wells If the aquifer is unable to provide <br /> steady flow through the existing well, then the wells will be evacuated and a rising-head slug test <br /> will be performed It is possible that the existing well will not provide accurate data because of <br /> swelling of the perforated openings due to the extended presence of petroleum hydrocarbons in <br /> that well <br /> Groundwater generated by the pump test will be contained in 550-gal fiberglass aboveground tank <br /> and held onsite until it can be treated by the selected groundwater treatment technology If <br /> groundwater contamination is too extensive for a pump and treat method to be cost- and time- <br /> effective, then an alternative technology known as air sparging will be tested for feasibility This <br /> will however, require that additional soil borings and sparge wells be completed <br /> • <br /> �'--� WshLL9/14!93 7 1685-030 sew <br /> &Associates, Inc <br /> Environmental scientists and Engineers <br />