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REMEDIATION TESTING AND DESIGN March 12 , 1993 RTD anticipates conducting short extraction tests with numerous wells and probes on the first day following the soil gas survey Based on the flow characteristics in the wells and probes , two :,r three will be used as extraction points for a full Cay of testi:: The VEFT will be conducted in two to three segments for a full dat, of extraction. The first segment will consist of applying an extraction vacuum to the top of the well casing , and the set,onc! segment will consist of applying the vacuum to the air/water interface using the drop pipe technique The third test will utilize another well with either the drop Pape or standard configuration During each VEFT, TVH levels of the extracted vapors will be monitored continuously with an OVA or FID. At the end of each test, a 1-dater Tedlar air bag will be fa-lled with extracted soil gas vapors for laboratory analysis The tedlar bags will be transported in iced storage under chain of custody documentation to a laboratory for analysis of TPHg and BTEX The laboratory results may be used to help design and size the vapor treatment system to be used during remediation Vacuum extraction will be conducted with a Sutorbilt Model 3ML p,Dsitive displacement blower --apable of extracting 100 standard cubic feet per minute ( scfm) under a vacuum load of 15 inches of mercury Extracted vapors will be routed through a 55 gallon water accumulator to remove any vaporized water Prior to discharge to the atmosphere , the extracted vapors will pass through 2 granular activated carbon (GAC) cannisters in series , each containing 175 pounds of vapor phase GAC. r , The duration for each test will he determined in the field based on initial flow and vacuum levels . In any event, RTD will conduct a full day of vacuum testing The actual testing scheme will be determined in the field by RTD in conjunction with Ultramar based on the results of initial testing . The ca'ture radius , _ P thus , the distance at which the pressure differential =created by a vacuum is measured in the lateral plane , will be noted by recording the vacuum gradient in neighboring probes and wells in inches of water ( "H?O ) using magnehelic differential pressure gauges The detection limit for the vacuum gradient will range from 0 01 to 5 . 0 "H2U Sample purge rates , vacuum readings and differential pressures will be recorded for further analysis . Any liquid wastes produced during the VEFT will be collected in the accumulator and transferred to 55-gallon DOT drums and temporarily stored on site Disposal, of extracted water is the responsibility of Ultramar 1 L 1� 3