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I*
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<br />17,000 ppmv, 200 ppmv, 3,000 ppmv, 270 ppmv, 1,200 ppmv, and 16 ppmv, respectively Monitoring
<br />points MW -9, MW -10, MW -11, MW -12, MW -14, MW -17, VE -1, and VE -2 had measured induced
<br />wellhead vacuums ranging from 0 72 to 0 75 inwc , 10 to 1 1 inwc , 0 63 to 0 68 inwc, 0 66 to 0 70 inwe,
<br />0 50 to 0 51 inwc, 0 34 to 0 36 inwc, 0 93 to 0 95 inwc, and 1 1 to 14 inwc, respectively No induced
<br />vacuum responses were observed at well MW -13 Field observations for this portion of the second phase
<br />of the VEFT were recorded and are sunimanzed as Table 6 Table 7, summarizes the soil vapor analytical
<br />data collected during this phase of the VEFT
<br />6.3 Vapor Extraction Feasibility Study Discussion and Conclusions
<br />During the VEFT, vacuum response data was developed by extracting soil vapor at the maximum applied
<br />vacuums of approximately 128, 120, and 84 inwc, and at the maximum flow rates of approximately 131,
<br />greater than 131, and 92 aefm from wells VE -1, VE -2 and VE -3, respectively The data collected
<br />demonstrates that significant vacuum influence (i e , induced vacuum measured greater than 0 10 inwc)
<br />was developed at radial distances of approximately 92, 66, and 71 feet from source vapor extraction wells
<br />VE -1, VE -2, and VE -3, respectively One well, MW -13, is located within the radius of influence for VE -
<br />1 and VE -3, and possibly VE -?_z and never showed any influence Since MW -13 is the only well that
<br />reported -data of this nature, it will be treated as do wioiiialy and will be disiegaided in tn.,-analysis Thi,
<br />rest of the data collected from the VEFT indicates that a radius of influence of at least approximately 66
<br />feet is sustainable at applied vacuums ranging from 84 to 128 inwc
<br />7.0 AIR SPARGE PILOT TESTING
<br />In order to assess the feasibility of implementing air sparge technology as a remedial measure for the site,
<br />field feasibility testing was necessary to evaluate the needed spargmg pressure, resultant flow, and radius
<br />of influence of an air sparging system at the site ATC prepared the Workplan for Additional Assessment,
<br />Remediatton Well Installation and Feasibility Studies, dated December 21, 2001 to address the need for
<br />field feasibility testing
<br />7.1 Air Sparge Pilot Testing System and Procedure
<br />Air Sparge Feasibility Testing (ASFT) was conducted on December 17, 2002 The ASFT utilized a trailer
<br />mounted 100 standard cubic feet per minute (SCFM) air compressor, pressure regulator, rotometers to
<br />measure flow, associated valves and piping, pressure measuring equipment, depth to water measurement
<br />equipment, dissolved oxygen measurement equipment, and a MiniRAE 2000TM Model PGM -7600
<br />portable volatile organic combustibles (VOC) monitor The ASFT was conducted in accordance with
<br />ATC's Standard Operating Procedures included in Appendix B
<br />The ASFT was performed by infecting filtered compressed atmospheric air into the groundwater -saturated
<br />zone through air sparge wells and monitoring the responses at observation points Groundwater levels,
<br />dissolved oxygen (DO) concentrations, and VOC concentrations were measured at various observation
<br />wellheads prior to, and periodically during the ASFT The ASFT was conducted at air sparge points AS -
<br />EZ 100966 CAP
<br />S TZ Serve\EZ 1009661Reports1100966CAP
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<br />ATC Associates Inc
<br />ATC Pro3ect No 43 25827 0026
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