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Treatability Study Report and Feasibility Evaluation for In Situ Petroleum Hydrocarbon Remediation Field Maintenance Shop #24, 8020 South Airport Way Ctnrktnn ('alifnrnia FMS-MW4, FMS-DPE2, and FMS-SVE1. Wells FMS-MW5 and FMS-DPE1 were fitted with caps with sample ports when not being tested. To determine the ROI of vapor extraction from wells FMS-MW5 and FMS-DPE1 during HVDPE, induced vacuum was periodically measured at the monitoring wells listed above. Vacuum measurements were collected from Magnehelic vacuum gauges. Vacuum influence measurements were recorded while the system was operating at applied vacuums ranging from 35 in. w.c. (FMS-DPE1) to 204 in. w.c. (FMS-MW5). Induced vacuum readings collected during stable operating vacuums of 35 in. w.c. at well FMS-DPE1 and 204 in. w.c. at well FMS-MW5 were used to estimate the vapor extraction radius of influence using the "1 % method" described in Section 3.2.6 of this report. 5.2.4. Advective Airflow Measurement A one -liter Tedlar° bag was filled with air and attached to the sample port at each monitoring point to evaluate advective airflow and to verify that airflow was occurring at the monitoring point(s) where induced vacuums were observed. The time required to deflate a Tedlar° bag was recorded and used to calculate the advective airflow rate. Near the middle of each HVDPE test (under stable operating conditions), advective airflow was measured at monitoring wells FMS-MW1, FMS-MW2, FMS-SVE1, FMS-DPE2. Advective airflow was also measured at well FMS-MW5 during testing of FMS-DPE1, and vice versa. 5.2.5. Field Measurements of Vapor Concentrations Before and periodically throughout HVDPE testing, field vapor samples were collected from the test wells. Samples were pumped from the sample ports into dedicated Tedlar° bags using a Gast° oil -less air compressor and measurements of VOCs, % LEL (as methane), oxygen, and carbon dioxide were recorded on field logs. 5.2.6. Vapor Sampling Shortly after initiating vapor extraction during each HVDPE test, a soil vapor sample was collected from the extracted vapor stream at the wellhead. Additional samples were collected from the extracted vapor stream at the wellhead at the end of testing, prior to completing the testing. A Gast° oil -less vacuum pump was used to collect soil vapor from the sample port on top of each well into a new Tedlar® bag. Samples were delivered to the analytical laboratory (BC Labs) under proper chain -of -custody and analyzed for TPH-g, VOCs, and fuel oxygenates using EPA Methods TO -3 and TO -14. 5.2.7. Groundwater Sampling Initial and final groundwater samples were collected from the discharge line of the submersible pneumatic pumps used for HVDPE testing at wells FMS-MW5 and FMS-DPE1. The samples were delivered to a State -certified laboratory (BC Labs in Bakersfield, CA) for analysis of TPH-d, TPH-g, VOCs, and fuel oxygenates using EPA methods 8015 and 8260B. 5.3. RESULTS 5.3.1. Vacuum Versus Flow Test Results Vacuum versus flow step tests were completed at wells FMS-MW5 (at the end of testing) and well FMS-DPE1 (at the beginning of testing) to evaluate the feasibility of vapor extraction while simultaneously extracting groundwater. The vacuum versus flow test began immediately after groundwater drawdown was maintained at the pump inlet. OTIE ��