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Treatability Study Report and Feasibility Evaluation for <br />In Situ Petroleum Hydrocarbon Remediation <br />Field Maintenance Shop #24, 8020 South Airport Way <br />Stockton, California <br />• Vacuum influences at the observation and wells, located at various distances from the <br />extraction point; <br />• VOCs in the influent vapor stream (pre-dilution/source), and in the head space of selected <br />monitoring wells, measured as ppmv, with a MiniRae® 2000 PID; <br />• VOCs parts per million volume (ppmv) , %LEL (as methane), oxygen (%), and carbon <br />dioxide (%) in the influent vapor stream (pre-dilution/source), and in the head space of <br />selected monitoring wells with a GasTech GT -408 multi -gas meter; and <br />• Depth to water in monitoring wells using a water level meter and in the SVE test well using a <br />transducer. <br />Additional short duration (less than 1 -hour) SVE tests were conducted at wells FMS-MW5, <br />FMS-DPE1, and FMS-DPE2, which are screened from 27.5 to 57.5 feet bgs, 20.1 to 60.1 feet <br />bgs, and 23.8 to 58.8 feet bgs, respectively. These short tests were conducted to assess the <br />feasibility of extracting soil vapor from wells screened at various intervals through the saturated <br />and vadose zones. <br />A timeline for SVE operations is provided in the Pilot Test Summary Data sheets included in <br />Appendix F. <br />The following sub -sections summarize the testing procedures <br />3.1.1. Vacuum Vs. Flow Step Test <br />After plumbing well FMS-SVE1 to the extraction equipment and collecting a set of background <br />measurements from the surrounding wells, vacuum versus flow step testing was conducted to <br />determine vacuums for subsequent ROI testing as well as future equipment requirements. <br />Vacuum measurements were read from Magnehelic° pressure/vacuum gauges, and vapor flow <br />rate was measured using a Dwyer DS-300Tm averaging pitot tube. Initially, a vacuum of <br />43 inches water column (in. w.c.) was applied to well FMS-SVE1. The vacuum was then <br />stepped up incrementally to a maximum vacuum of 143 in. w.c. At each step, measurements of <br />induced vacuum and resulting flow rate were recorded. <br />Additional short step tests were also conducted at wells FMS-MW5, FMS-DPE1, and <br />FMS-DPE2 to assess the feasibility of extraction soil vapor from wells screened across the <br />water table. The applied vacuums tested at wells FMS-MW5, FMS-DPE1, and FMS-DPE2 <br />ranged from 136 to 190 in. w.c.(10 to 14 inches of Mercury [in. Hg]), 25 to 115 in. w.c., and 68 to <br />204 in. w.c. (5 to 15 in. Hg), respectively. <br />3.1.2. Induced Vacuum Measurement <br />Prior to beginning soil vapor extraction from well FMS-SVE1, PVC slip caps with sample ports <br />(ball valves fitted with tubing) were installed on the casings of the monitoring wells listed in <br />Section 3.1 above. To determine the radius of influence of vapor extraction from well <br />FMS-SVE1, induced vacuum was periodically measured at the monitoring wells listed above. <br />Vacuum measurements were read using low range Magnehelic differential pressure gauges. <br />Vacuum influence measurements were recorded prior to the start and during SVE operations at <br />applied vacuums ranging from 25 to 140 in. w.c. The resulting observations were used to <br />calculate the SVE ROI. <br />OTI E 15 <br />