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Treatability Study Report and Feasibility Evaluation for In Situ Petroleum Hydrocarbon Remediation Field Maintenance Shop #24, 8020 South Airport Way Stockton, California 3.0 SVE TREATABILITY TEST 3.1. PROCEDURES To investigate the viability of soil vapor extraction for site remediation, tests were performed on May 14, 2012 to determine the effective ROI for SVE beneath the site, and document flow vs. vacuum relationships. A 25 horsepower liquid ring blower with a 450 standard cubic feet per minute (scfm) capacity propane -fired thermal oxidizer was provided and operated by CalClean Incorporated of Tustin, California for the test. The vapor extraction and treatment system used during pilot testing was exempt from air permitting as described in Section 2.1.1. of this report. Water collected by the knockout tank during SVE testing was pumped into the onsite 4,000 - gallon storage tank for offsite disposal. A Troll° 9500 multi -parameter groundwater quality monitor including an optical dissolved oxygen probe was installed at the bottom of well FMS-SVE1 to monitor for the presence of water in the SVE well during the SVE test. An OTIE California licensed Civil Engineer directed testing, and all measurements and sample collection was completed by OTIE Project and Staff Engineers. The vadose zone has been described as having several distinct zones identified by differing soil compositions. A shallow zone of silts and clays having a low permeability exists from surface to a depth of approximately 20 feet bgs. This low permeability zone is underlain by higher permeability sand zone which extends downward to depths ranging from 25 feet bgs (at FMS-MW5) to 28.5 feet bgs (at FMS-SVE1) (Figure 3 and 4). The site -wide depth to groundwater during SVE testing was approximately 30 feet bgs. SVE testing was first conducted at well FMS-SVE1 for a duration of approximately 6 hours. Well FMS-SVE1 is screened from 18.5 to 28.5 feet bgs. The well was plumbed to the extraction system using 2 -inch -diameter schedule 40 PVC pipe and 2 -inch -diameter flex hose, and vacuum was initiated. During extraction, the vadose zone was monitored using the following wells: • FMS-MW1 (screen interval 26-46 feet bgs); • FMS-MW2 (screen interval 26-46 feet bgs); • FMS-MW4 (screen interval 24.5-49.5 feet bgs); • FMS-MW5 (screen interval 27.5-57.5 feet bgs); • FMS-DPE1 (screen interval 20.1-60.1 feet bgs); and • FMS-DPE2 (screen interval 23.8-58.8 feet bgs). Well construction details are summarized in Table 1. At a minimum, the following parameters were monitored during SVE testing at well FMS-SVE1: • Background/natural vacuums/pressures at the test and observation wells; • Source extraction flow rate; • Vacuum at the source well; • Advective airflow, measured with a 1 -liter Tedlar0 Bag; OTIE 14