ARCHIVED REPORTS_XR0006029 - Laserfiche WebLink

Home Browse Search

I lie 31 August 2004 AGE-NC Project No 95-0173 IPage 8of10 Between 30 December 2003 and 24 March 2004 (First Quarter 2004), the SVE unit operated a total of 2,040 hours(Table 6) The average analytical results(approximately 340µg/1)of the influent SVE air flow samples(Table 5),average flow rates(approximately 71 scfrn,Table 6) and the operational period (2,040 hours) were used to calculate the approximate mass of extracted gasoline during this period During the First Quarter 2004 operational period, the mass of hydrocarbons extracted by the SVE system was calculated to be approximately 184 pounds, or equivalent to a volume of 30 gallons of gasoline Added to the estimated 1,899 gallons ofhydrocarbons extracted from the SVE system since I 11 April 2000 (start-up), the total volume of hydrocarbons extracted to date is estimated at 1,929 gallons (Table 7) A plot of the cumulative volume (gallons) of hydrocarbons extracted to date is included with Appendix E The volume/mass calculations for extracted hydrocarbons are included with Appendix F 4.4. CONCLUSIONS . The implications from the March 2004 ground water monitoring event are as follows • Ground water flow direction at the site was generally oriented northeast across the site with a gradient was as great as 0 003 ft/ft Due to the generally low gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify ground water flow direction I • The increase of ground water elevation of approximately 2 65 feet between December 2003 and the March 2004 monitoring events is probably due to seasonal fluctuation • Ground water at the site was significantly above the screen intervals (drowned) of wells AW-1 (A and B), AW-2 A and B) and MW-13 (A, B and C) and yield samples more representative of deeper ground water conditions The ground water elevation appeared to be within or near the screen intervals of all other wells at the site and should be representative of shallowest ground water conditions • Ground water elevation data collected on 19 March 2004 does not suggest that ground water mounding may have occurred due to the on-going IAS activities • The elevated concentrations of petroleum hydrocarbons detected in samples collected from wells MW-4(screened 30 to 50 feet),AW-1A(screened 39 to 44 feet)and AW-lB(screened 50 to 60 feet bsg) Indicate that these wells are within the remaining dissolved petroleum hydrocarbon "core area" of the plume (Figures 4) • The rapid decrease is dissolved petroleum hydrocarbon concentrations at AW-2A and AW-2B can be attributed to the ongoing air sparging activities at well AW-2B during Advanced GeoEnvironmental,Inc i