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.�. Geolagica(Technirs Ex. Pagr 5 Pilot Test Report g COE-Arco Project No, 750.2 August 8,2000 Laboratory Analyses of Air Samples Influent air samples were collected from each vapor extraction well approximately two hours after the well was connected to the IC. Two samples were collected from VEW-1, one when the well was first connected to the IC and the other approximately 2-hours after the well had been connected to the IC. An effluent air sample was collected from the exhaust stack on the IC while it was drawing from VEW-3 to show that the IC was effectively controlling emissions. The laboratory results show that moderate levels of BTEX and MTBE and high levels of TPI]-G were extracted from the vadose zone. The levels extracted from VEW-1 showed a slight increase during the two-hour duration of the test. It is expected that the levels would continue to increase for several days or weeks, until equilibrium is reached, once an extraction system is installed. The laboratory analytical data is summarized in 'fable 3 of Appendix A. Rate of Hydrocarbon Removal The volume of extracted hydrocarbons during the pilot test can be estimated using the following equation: Volume of Hydrocarbons = Concentration * Extraction Rate VEW-1 Concentration =32mg of TPH gasoline/liter of air Extraction Rate=39.7 ft3/min. *28.33 liters/ft3 — 1,124.7 liters of air/min. 1,124.7 liters air/min. * 32 mg TPH gasoline/liter of air=35,990.4 mg TPH gasoline/min. .... 35,990.4 mg TPH gasoline/min. * gram/1,000 mg * kg/1,000 g=0.036 kg/min. 0.036 kg/min. * 2.2 lbs/kg=0.0792 Ib. TPH gasoline/minute 0.0792 lb. TPH gasoline/minute * 1,440 minutes/day- 114 lbs. hydrocarbons removed per day The removal rates for the other wells were calculated using the same equation. 4.0 DATA ANALYSES 4.1 Pilot Test Observations The vacuum drawdown monitoring in the surrounding monitoring wells (MW-1, MW-2 and MW-3was lower then first expected and did not fit with what was expected. VEW-1 and VEW-4howed vacuum influence (greater then 0.1 inch) out to all of the surrounding monitbring wells. Extracting from VEW-2 and VEW-3 did not show vacuum influence above 0.1 inch in the surrounding monitoring wells. However, there was good vacuum influence between all of the vapor extraction wells. &. Vacuum readings from VEW-2 and VEW-3 while these wells were connected to the IC were very high. This indicates that these wells were screened across relatively tighter geologic 4, layers. The smaller radius of influence of these two wells supports this conclusion. The vacuum in the monitoring wells was observed to respond within a matter of minutes, to changes made to the extraction rates from the vapor wells. The vacuum drawdown appears to have stabilized in the wells that showed vacuum readings. 4 �r