Laserfiche WebLink
12 July 2012 <br />AGE-NC Project No. 02-0926 <br />Page 3 of 7 <br />inch (psi) and a flow of 1 to 2 standard cubic feet per minute (scfm) were maintained at the <br />compressor to the well. During the IAS pilot testing activities, DO measurements <br />(milligrams per liter and percentage) were collected from observation wells MW-1 through <br />MW-5 (Table 3). The following is a summary of findings: <br />DO was measured at concentrations ranging from 2.23 milligrams per liter (mg/I; <br />24.5%) to 4.81 mg/I (56.9%) in well MW-1; <br />DO was measured at a concentration of 5.10 mg/I (58.4%); the well was mostly <br />inaccessible during the extended 60-day pilot test; <br />DO was measured at concentrations ranging from 0.66 mg/I (7.1%) to 2.94 mg/I <br />(33.9%) in well MW-3; <br />DO was measured at concentrations ranging from 2.43 mg/I (25.7 %) to 6.41 mg/I <br />(75.2%) in well MW-4; and <br />DO was measured at concentrations ranging from 0.73 mg/I (8.0%) to 8.80 mg/I <br />(102.5%) in well MW-5. <br />Plots of dissolved oxygen versus time in wells nearest to the sparging location (MW-1 and <br />MW-5) were used to evaluate the lateral influence of the pilot sparging. Based on these <br />plots a significant increase in DO was observed at the location of well MW-5 <br />(approximately 7 feet from active sparging location; Appendix C). Baseline dissolved <br />oxygen was measured at 0.73 mg/I and reached a maximum measured concentration of <br />8.80 mg/I at the termination of the pilot test. Plots of the 72-hour pilot test were created on <br />the same graph and clearly illustrate the relationship of dissolved oxygen versus time, while <br />sparging is being performed at well MW-6. <br />DO concentrations in well MW-1 show a minor increase in dissolved oxygen over time, <br />while all other wells illustrate a fluctuation in DO concentration. The general fluctuations <br />likely indicate that the sparging radius of influence is limited to areas near the sparging <br />point (MW-6) or the lateral migration of low concentrations of dissolved oxygen (mixing) <br />may have occurred over a short span of time. <br />4.0 SOIL VAPOR EXTRACTION FINDINGS <br />From field and laboratory data collected at the SVE remediation system during the 60-day <br />IAS pilot test performed between 16 March and 16 May 2012, AGE determined the <br />average TPH concentration, the average flow rate and calculated the approximate mass <br />and volume of hydrocarbons removed. <br />Advanced GeoEnvironmental, Inc.