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Air Sparging Pilot Test Related Activities Report and Remedial Action Work Plan
<br />Former Countryside Market, Stockton, California April 30, 2015
<br />4.0 AIR SPARGING FEASIBILITY TESTING
<br />AS feasibility testing consisted of two separate tests, completed on two different days, starting with
<br />AS injection at AS-1 on January 28, 2015 followed by testing at AS-2 on January 29, 2015. During
<br />each test, AS was conducted at low, medium, and high injection flow rates.
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<br />4.1 Feasibility Test Equipment and Installation
<br />AS test equipment included a rented diesel powered air compressor capable of 20 to 30 standard
<br />cubic foot per minute (scfm), sparge manifold, and an air injection well head assembly. The sparge
<br />manifold consisted of multiple stage oil/water coalescing filters, a pressure regulator, valves,
<br />pressure gauges, temperature gauges, air hoses, rotameters (flow meters with control valves), and
<br />a helium tracer injection port. The helium tracer injection port was equipped with a dedicated
<br />rotameter, temperature gauge, and pressure gauge to calculate the helium flow rate separate from
<br />the air flow rate and combined stream flow rate. Prior to testing, hoses were connected from the
<br />air compressor and helium tank to the sparge manifold and from the manifold to the injection well
<br />head assembly (air-tight seal) installed on the air injection test well.
<br />Monitoring equipment used during testing included a Rae Systems Mini-Rae lite PID, an
<br />SPX MGD-2002 multi-gas leak detector (helium detector), In-Situ, Inc. Troll 9500TM and YSI
<br />600XLM multi-parameter data logger (data loggers) and various magnehelic pressure/vacuum
<br />gauges. Each data logger was equipped with dissolved oxygen (DO), pressure (water level),
<br />pressure (head-space pressure within the sealed casing), temperature, pH, conductivity, and
<br />oxidation-reduction potential (ORP) sensors. Compression style fittings were installed to provide a
<br />tight seal around the vented communication cables, while sample ports with valves were utilized for
<br />pressure, PID, and helium monitoring throughout testing.
<br />Prior to testing, data loggers were deployed into observation wells OBS-1 and MW-5. An
<br />additional data logger was deployed in AS-1 and AS-2, depending on the stage of the AS test.
<br />Transducers were deployed into outlying monitoring wells MW-3, MW-6, and MW-7.
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<br />4.2 Soil Vapor and Groundwater Monitoring and Sampling
<br />4.2.1 Monitoring and Sampling Activities
<br />Monitoring and sampling activities were completed at the Site, including groundwater and soil
<br />vapor sampling preceding and following AS pilot testing activities. Pre-pilot test groundwater
<br />samples were collected on January 13, 2015, and post pilot test groundwater samples were
<br />collected on January 29, 2015 from wells OBS-1, AS-1, and AS-2. Pre-pilot test soil vapor
<br />samples were collected from VW-1 and OBS-1 on January 19, 2015 and post pilot test soil vapor
<br />samples were collected on January 28, 2015.
<br />Groundwater levels were gauged from the TOC using an electronic water level indicator graduated
<br />to 0.01 foot. The survey tops of casing elevations are referenced to mean sea level. Groundwater
<br />4-1 The Source Group, Inc.
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