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' 07 September 1999 <br /> • <br /> AGE-NC Project No 95-0104 <br />' Page 5 of 8 <br />' 43 RESULTS OF VAPOR EXTRACTION PILOT TEST <br /> Between 22 July 1999 and 27 August 1999, the SVE/IAS pilot test was operational for 691 hours <br />' During the operational period, flow rates ranged from 25 to 70 standard cubic feet per minute (scfm) <br /> at 0 20 to 1 75 inches of water of differential pressure, the induced vacuum stabilized at <br />' approximately 0 80 inches of water during the pilot test Hydrocarbon concentrations were measured <br /> at regular intervals at the VES inlet prior to air dilution PID field measurements were recorded at <br /> an average 322 25 parts per million (ppm) at the beginning portion of the July-August 1999 <br />' SVE/IAS pilot test and were recorded at an average 260 ppm near the end portion A trend of <br /> declining PID field measurements Is noticeable between the March-April PID field measurements <br /> (Quarterly Report-April 1999, dated 07 May 1999) and the July-August PID field measurements <br />' Field measurements are summarized in Table 4 <br /> 44 ANALYTICAL RESULTS OF SOIL GAS SAMPLES <br /> • During the SVE pilot test, TPH-g was detected in soil gas samples collected from VW-1 at <br /> concentrations ranging as high as 3,400 Mgll <br /> BTEX compounds were detected in soil gas samples collected from VW-1 at concentrations as high <br /> as 100 77µg/l Benzene was not detected in the first three soil gas samples collected during the test, <br /> but was detected at a concentration of 16 ugll in the fourth and final soil gas sample collected <br />' Analytical results of soil gas samples are summarized in Table 3 The laboratory report (Precision <br /> Enviro-Tech Analytical Laboratory Sample I D "s PE5666 PE5715, PE5768, PE5807 and PE5851) <br /> and chain-of-custody forms are presented in Appendix C <br /> 4 5 MASS CALCULATION OF RECOVERED PRODUCT <br /> The hydrocarbon mass removed during the operating period was calculated using the following <br /> equation M = C•Q•t <br /> NAhere M = cumulative mass recovered (kg) <br /> C = vapor concentration (kg/m3) <br /> Q = extraction flow rate (m3/hr) <br /> t = operational period, in hours <br /> Between 28 July 1999 and 27 August 1999, the extraction unit operated a total of 691 hours The <br /> analytical results of the vapor samples combined with average flow rates (approximately 65 cfm) <br /> and the operational period were used to calculate the approximate mass of extracted gasoline during <br /> these periods <br /> I4dianced GeoEmironmental,Inc <br />