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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 />information were recorded in the field notes and on the COC form(s). Field documentation
<br />related to well installation is presented as Appendix D.
<br />Analytical results for soil samples collected from FMS-DPE1, FMS-DPE2, AS -1, and SVE-1, as
<br />shown in Table 2, are consistent with previous findings in documenting that petroleum
<br />hydrocarbons and related constituents are concentrated primarily in the capillary zone, from
<br />approximately 25 to 35 feet bgs. With the exception of SVE-1, which was installed within the
<br />outline of the former gasoline UST, as described above, only trace or nondetectable
<br />concentrations of TPH-g, TPH-d, and VOCs were found in soil above the capillary zone.
<br />2.4. WELL DEVELOPMENT
<br />A minimum of 48 hours after installation, to allow sufficient time for well materials to cure, the
<br />wells screened in groundwater (AS -1A/1 B, FMS-DPE1, and FMS-DPE2) were developed by
<br />surging and swabbing using a surge block. Development water was pumped out of the wells
<br />into waste containers, and ultimately transferred from those containers into the wastewater tank
<br />utilized for pilot testing. The purpose of developing new monitoring wells is to remove the
<br />residual materials remaining in the well after installation has been completed. Development
<br />procedures were continued until water removed from the well was clear and free of any visible
<br />sediment, and the physical parameters of temperature, pH, and conductivity had stabilized.
<br />Development water was stored onsite until properly characterized, along with other waste water
<br />generated during the treatability study, and transported offsite for disposal. Waste disposal
<br />documentation for this wastewater is presented with waste documentation for well spoils and
<br />treatability study waste in Appendix E.
<br />2.5. GROUNDWATER SAMPLING
<br />During implementation of the treatability study, various groundwater samples were collected to
<br />evaluate groundwater conditions in the target area associated with AS and HVDPE testing. On
<br />14 May, 2012, and prior to implementation of any treatability study activities, baseline samples
<br />were collected from wells FMS-MW5, FMS-DPE1, and FMS-DPE2. On 17 May, 2012, additional
<br />samples were collected from FMS-MW5, FMS-DPE1, and FMS-DPE2. The purpose for these
<br />samples was to document baseline (initial) and final impacts, if any, upon groundwater in the
<br />target area owing to the AS treatability study, which is described in further detail in Section 4
<br />below. Purging and sampling from the wells were performed using low -flow (micro) purging
<br />technique to achieve stabilization of the physical parameters of temperature, pH, dissolved
<br />oxygen, and conductivity, in accordance with standard practices. Prior to initiating sampling
<br />activities, depth to water in each well was measured using an electronic interface probe. No
<br />SPH were identified in any of the wells. Field documentation associated with this effort is
<br />presented in Appendix D.
<br />Finally, during HVDPE testing on 17 and 18 May, 2012, initial and final groundwater samples
<br />were collected from the pumps used in FMS-MW5 (17 May) and FMS-DPE1 (18 May). Samples
<br />collected from each of the wells, as described above, were analyzed by BC Laboratories, under
<br />full COC documentation, for the following analyses:
<br />• TPH-g and TPH-d using U.S. EPA Method 8015 -Modified; and
<br />• VOCs including Naphthalene, BTEX, and Fuel Oxygenates using U.S. EPA Method 8260B.
<br />Analytical results for groundwater samples are summarized in Table 3. Laboratory analytical
<br />reports and COC documentation associated with groundwater samples are presented in
<br />OTIE 12
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