Laserfiche WebLink
REMEDIATION TESTING AND DESIGN March 29 , 1993 <br /> deterMined by Mr Fenneth Earnest of Ultramar Each probe or well <br /> location was when purged 4 to 5 casing volumes of soil oas using a <br /> diaphragm pump The purged soil bas was then field screened for the <br /> Presence of total volatile hyd,ocarbons (TVH ) as methane , using a <br /> Portable flame ionization detector (IID ) . Soil gas samples were <br /> collected from selected wells into new 1 liter Tedlar a3--r bags for <br /> laboratory analysis The air bags were transported in iced storage <br /> under chain of custody documentation to West Analytical Laboratory of <br /> Davis , California Samples were analyzed for total petroleum <br /> hydrocarbons as gasoline (TPHg ) and for benzene , toluene , <br /> ethylbenzene , and total xylenes (BTEX) using modified EPA Method 8015 <br /> and EPA Method 8020 respectively <br /> rVacuum Extraction Test-Lng <br /> Vacuum extraction was conducted using the vapor probes and existing <br /> wells Prior to conducting the tests , an air discharge permit waiver <br /> was obtained from San Joaquin Valley Air Pollution Control District <br /> A copy of the regulatory correspondence is contained in Appendix A <br /> Two 1-hour tests were performed using vacuum extraction wells VW-2a <br /> and VO-2b as extraction points . Also , vacuum extraction step testing <br /> was conducted on each vacuum extraction well and monitor well MW-3 <br /> For the step test, extraction well vacuum and flow rates were recorded <br /> for a range of vacuum conditions . Vacuum extraction was conducted <br /> using the RTD vacuum extraction testing unit (VETU) consisting of a <br /> Sutorb.ilt Model 3ML positive displacement blower capable of extracting <br /> 100 standard cubic feet per minate ( scfm) with a vacuum of 15 inches <br /> of mercury ( "Hg ) , a 55 gallon water knock-out device and, two drums in <br /> series , each containing 175 pounds of vapor phase activated carbon. <br /> tThe first two tests incorporated standard extraction, testing . A <br /> clear, flexible PVC line was connected from the Sutorbilt to an <br /> airtight fitting at VW-2a Standard vacuum extraction was conducted <br /> for a period of 65 minutes until stable vacuum conditions were noted <br /> in the observation wells . The second test utilized well VW-2b as the <br /> extraction point The second test was conducted for a period of 65 <br /> minutes <br /> l <br /> During extraction, the capture radius , the distance at which the t <br /> pressure differential created by a vacuum is measured in the lateral " <br /> plane , was noted by recording the vacuum gradient in inches of water <br /> ( "H20) using magnehelic gauges fitted to the surrounding probes and <br /> wells The detection limit for the gauges ranged from 0 01 to 2 0 <br /> "H2O. Extraction flow rate and vacuum was monitored using a 5 to IOU <br /> scfm flow meter equipped with a 0 to 30 "Hg vacuum gauge Extracted <br /> vapors were monitored for TVH using the portable FID . Prior to and <br /> followa-ng the completion of each test, a Tedlar airbag sample of the <br /> extracted soil gas was collected for laboratory analysis for TPHg and <br /> BTEX <br /> 7 <br /> I <br /> 2 <br />