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2 x"113 3 S., 5� <br /> 6 <br /> 2, <br /> of vapor-phase TPHS and 35.5 pounds of vapor-phase benzene. At best, the DPE <br /> systems current TPHg and benzene vapor-phase mass removal rates are 3.1 and <br /> 0.05 pounds per day,which is considered low. <br /> Z As expected dissolved-phase mass removal is negligible. As of February 2, 2009, the <br /> DPE system removed in total 10.4 pounds of dissolved-phase TPHg and 0.29 pounds of <br /> dissolved-phase benzene. Groundwater extraction is primarily being conducted to <br /> dewater saturated soils and allow vapor extraction of submerged hydrocarbon mass. <br /> Groundwater extraction is not considered an effective method to remediate <br /> dissolved-phase TPHg and BTEX in general and specifically for this site. <br /> 3.3.3 RADIUS OF INFLUENCE <br /> Wells VEW-1 and VEW-6 are true SVE wells since they are completed in the vadose <br /> zone. Wells VEW-2, VEW-3, VEW-5, and VEW-7 are screened within the vadose zone <br /> and approximately 15 feet into groundwater. VEW-4 is a deep extraction well that has a <br /> submerged screen interval from 45 to 65 fbg. Well locations and screen intervals were <br /> placed in the known impact areas based on historical soil and groundwater analytical <br /> data. DPE stingers were historically placed near the bottom of the DPE wells during <br /> extraction to achieve full dewatering. <br /> CRA periodically measured depth-to-water and induced vacuum in the wells to assess <br /> the DPE systems radius of influence. Some data variations can be attributed to the <br /> differing screen intervals. Depth-to-water measurements did not show induced <br /> groundwater drawdown indicating that`the groundwater drawdown profile edge begins <br /> at less than 20 feet from the extraction point. Induced vacuum measurement at <br /> observations wells indicated that the vacuum radius of influence extends more that <br /> 40 feet. <br /> 3.3.4 WELL VEW4 <br /> Since well VEW-4 has a deeper and submerged screen interval, the DPE system was not <br /> able to effectively dewater this well using the stinger configuration. To accommodate <br /> DPE from this well,CRA installed an electric submersible pump in this well and made a <br /> SVE connection at the top of the wells casing. The configuration was used from <br /> January 27 to February 2, 2009 to assess DPE from this well. The groundwater yield <br /> from this well was approximately 3.8 gallons per minute, which kept the groundwater <br /> stabilized at 58 fbg in this well. Approximately 24,487 gallons of groundwater was <br /> WVcv <br /> XXXXX(XX) - 6 CONESTOGA-ROVERS&ASSOCIATES <br />