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�• v <br /> REMEDIATION TESTING AND DESIGN May 28, 1993 <br /> range of 3/16-inch drilled perforations at one end with a forged <br /> point . All probes will be decontaminated by steam cleaning prior <br /> to arrival on the site. They will be pneumatically installed to a <br /> depth of, but not more than, approximately twenty feet below ground <br /> surface. The installed depths of the probes will be determined in <br /> the field by the registered geologist from RTD and by a <br /> representative of Ultramar, Inc. (Ultramar) . <br /> RTD and Ultramar have extensively discussed the limitations and <br /> potential dangers associated with driving temporary probes . Given <br /> these limitations, Ultramar, as our client and site owner/operator, <br /> is entirely responsible for selecting probe locations . All probes <br /> driven by RTD will be at the direction of Ultramar. RTD reserves <br /> the right to refuse to drive any probes at its sole discretion. <br /> Following installation, a pump induced vacuum will be applied to <br /> each probe to purge resident soil gas . Sample purge rates and <br /> vacuums will be monitored and recorded for each probe. Soil gases <br /> from the probes will be analyzed for total volatile hydrocarbons <br /> (TVH) using a Beckman Model 440 Total Hydrocarbon Analyzer Equipped <br /> with a Flame Ionization Detector (FID) . In addition, RTD will <br /> collect soil gas samples into 1-liter Tedlar air bags from up to <br /> five probes to be sent to a certified laboratory for analysis of <br /> total petroleum hydrocarbons as gasoline (TPHg) and benzene, <br /> toluene, ethylbenzene and total xylenes (BTEX) . The soil gas TVH <br /> data will be mapped on a scaled site plan to aid in the evaluation <br /> of hydrocarbon impacted areas and possible migration pathways . <br /> Upon completion of the SGS, the probes will be used for the VEFT. <br /> Once the VEFT is completed, the probes will be removed and the <br /> probe holes sealed with portland cement slurry. <br /> Vacuum Extraction Feasibility Testing <br /> A VEFT using the temporary vapor probes will be conducted to <br /> determine the effectiveness of using vacuum extraction technologies <br /> for remediation of impacted soils, if present . <br /> Vacuum extraction will be conducted with a Sutorbilt Model 3ML <br /> positive displacement blower capable of extracting 100 standard <br /> cubic feet per minute (scfm) under a vacuum load of 15 inches of <br /> mercury. Extracted vapors will be routed through a 55-gallon water <br /> accumulator to remove any vaporized water. Prior to discharge to <br /> the atmosphere, the extracted vapors will pass through two granular <br /> activated carbon (GAC) cannisters in series, each containing 175- <br /> pounds of vapor phase GAC. <br /> The duration for each test will be determined in the field based on <br /> initial flow and vacuum levels . Based on these flow and vacuum <br /> level characteristics of the probes as predetermined in the SGS, <br /> two or three will be used as extraction points for a full day of <br /> testing. The VEFT will be conducted in two to three segments . <br /> Each segment will consist of applying an extraction vacuum to the <br /> top of the probe and recording the vacuum gradient in neighboring <br /> probes . The actual testing scheme will be determined in the field <br /> 2 <br />