Laserfiche WebLink
1 <br /> 1444 MARIPOSA ROAD <br /> WKA No 2938 05 <br /> August 26, 1999 <br /> Page 8 <br /> to 423 ppm Two vapor-phase activated carbon camsters were used as emission control devices <br /> during the pilot test <br /> The vapor extraction junction manhole was used as the vapor extraction well and wells VEW1, <br /> VEW2 and VEW3, MWI, and MW2 were used as the observation wells during the pilot test <br /> The horizontal distances between the function manhole and vapor extraction wells VEWI, <br /> ' VEW2, VEW3,MWI, and MW2 are approximately 30, 50, 40,48, and 112 feet, respectively <br /> Two influent soil gas samples ASI and AS2 were obtained during the pilot test Sample <br /> AS 1 was obtained approximately 20 minutes into the test and sample AS2 was obtained at <br /> approximately 4 hours into the test The samples were obtained by connecting 1-liter <br /> Tedlar bags to the influent sampling port of the blower The samples were submitted under <br /> ' chain of custody to a California-certified laboratory for analysis of TPH as gasoline using <br /> Modified EPA Method 8015, and BTEX using EPA Method 8020 <br /> TPH as gasoline was detected in samples AS 1 and AS2 at concentrations of 3,316 ppm and <br /> 2,912 ppm, respectively Benzene was not detected in sample AS 1 but was detected in AS2 (8 <br /> ' ppmv) Low concentrations of toluene, ethylbenzene, and total xylenes ranging from 10 9 ppm <br /> to 51 ppm were detected in samples AS 1 and AS2 <br /> vacuum pressure of approximately 35 to 38 inches of H 0 <br /> During the test, an average differentialp pp y z <br /> was measured at the vapor extraction junction manhole A vacuum extraction flow rate of <br /> approximately 280 standard cubic feet per minute (scfm)was observed in vapor extraction <br /> framework(manhole) Vacuum pressure and time were measured at the observation wells using <br /> Magnehelic pressure gauges The maximum observed vacuum pressure draw-downs in wells <br /> VEW1, VEW2, and VEW3 were approximately 10, 6 9, and 6 9 inches of H20, respectively <br /> Based on data collected during the test, a minimum radius of influence of approximately 50 feet <br /> can be achieved using a vacuum pressure of at least 35-inches of water at the site <br /> ' WALLACE KUHL <br /> Rer)&-dpaper &ASSOCIATES INC <br />