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i <br /> GROUND ZERO ANALYSIS, INC. <br /> i ' A plot of the step test data indicate that for vacuums greater <br /> than approximately 10 inches of water the relationship between <br /> ' vacuum and flow is linear and can be approximated by the <br /> formula Q = 0 68V + 12 where Q is flow in CFM and V is vacuum <br /> in inches of water A plot of the step test data is presented <br /> E as Figure 3 The flow ra-es observed in each of the other <br /> ' wells tested were higher per unit of applied vacuum than the <br /> flow rate observed in VW-4 It is unclear if the slope factor <br /> (0 68) determined for VW-4 could be applied with any <br /> ' justification to the other wells <br /> Vapor Test Well VW-6 <br /> During the vapor extraction test using test well VW-6 as the <br /> extraction well , induced vacuums were observed in wells VW-1 <br /> and VW-3 almost instantaneously, and in well VW-4 within 6 <br /> ' minutes No significant induced vacuums were observed in <br /> wells VW-2, VW-5, and MW-13 during the length of the test <br /> Based on these results an applied vacuum of 23 inches of water <br /> and a flowrate of 33 cfm appears to be achievable using test <br /> i well VW-6 as an extraction well Based on these results and <br /> results from longer tests performed on the other wells, a <br /> radius of influence of approximately 25 to 30 feet is also <br /> indicated <br /> A summary of VET monitoring data is presented in Table 1 Copies <br /> of field data notes are included in Attachment 2 <br /> Vapor concentrations were monitcred during testing and sampling at <br /> each vapor well with a flame ionization detector (FID) Field <br /> recorded vapor concentrations consistently exceeded 10, 000 parts- <br /> per-million (ppm) during extraction from each of the wells Field a <br /> vapor concentrations are considered order of magnitude only and are <br /> subject to the results of laboratory analysis <br /> Estimated Radius of Influence <br /> Utilizing induced vacuum and distance measurements obtained during <br /> the VET, an effective radius of influence was estimated for test <br /> wells VW-1, VW-2 , VW-3 , VW-4 , and VW--6 The estimated radii of <br /> ' influence for the wells is presented on Figure 4 The effective <br /> radius of influence has been defined as the radial distance from a <br /> vapor extraction well at which recorded vacuum levels suggest that <br /> ' subsurface airflow occurs and is presumed to be sufficient for <br /> remediation Ground Zero assumes that an induced vacuum of 10 of <br /> applied vacuum, or no less thar_ 0 25 inches of water, should be <br /> sufficient to induce subsurface airflow within the zone of <br /> influence, depending on the soil type <br /> 6 <br />