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1 <br /> i(VATC <br /> A S S O C I A T E S I N C <br /> to remove the obstruction The ng was used to advance drill rods to 30 feet bsg and <br /> ' approximately 70 gallons of grout was pumped into the well <br /> 1 On Apnl 22, 1999, ATC performed a short-term air sparge test Well MW-1 was used as the air <br /> infection point An air compressor capable of producing flows up to 10 cfm was used to <br /> ' pressurize the well casing to 10 pounds per square inch (psi) ATC attempted to initialize airflow <br /> but the airflow reading was zero The pressure in the well was incrementally increased to 100 psi, <br /> the maximum pressure the compressor could produce Helium tanks were also used to increase <br /> the pressure in the well but the airflow reading remained zero Helium is used as a tracer in <br />' groundwater to aid in the determination of an effective radius of influence for air sparging <br /> Helium measurements were taken from adjacent well VW-4, seven feet away, but no helium was <br /> detected It was uncertain whether the lack of airflow was a result of compressor size or the <br /> subsurface stratigraphy The air sparge test was terminated During the subsequent vapor <br /> extraction test, a helium reading was taken from well VW-5s Helium was measured at 20% at a <br /> distance of 17 feet from the sparge well <br />' Following the air sparge test, a vapor extraction test was performed using vapor well VW-1 as the <br /> vapor extraction point Vapors were extracted for approximately 2 hours using an IC engine <br /> equipped with a 5-hp blower and a moisture knockout chamber Two influent vapor samples and <br /> one effluent vapor sample were collected during the test Results and field readings from the <br /> 1 short-term vapor extraction and air sparge tests performed on April 22, 1999 are summarized in <br /> Tables 5 and 6 <br /> During the vapor extraction test, extraction flowrates ranging from 35 to 42 cfin resulted in <br /> vacuums of up to 0 6 inches of water in vadose well VW-5s located 17 feet from the extraction <br /> well Vacuums measured in wells VW-5d, VW-2d, and RW-1 were less than those measured lv <br /> during the first pilot test because the subsurface had not equilibrated following the sparge test <br /> Again, no response was observed in wells MW-1 and VW-4, located dust 6 to 7 feet from the <br /> extraction well Laboratory results of the vapor samples indicated that volatile hydrocarbons <br />' w 162574 011CAP report doc 6 <br />