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4.0 System Description and Data Collection Procedures 1 This section describes the pilot test system and the field data collection procedures. Field implementation and supporting activities are presented in Section 5.0. 4.1 Pilot Test System The system proposed for this pilot test will consist of an air compressor system, air conveyance piping, and a biosparge well. Figure 5 shows a schematic configuration of a field pilot test system to be used for the site. The system and its components are described in further details in Section 4.1. 4.1,1 Observation and Biosparge Well To ensure that test data collected will be representative of the site condition, a biosparge test well (labeled as SP -1) will be installed in the core of the contaminant plume, i.e., near the former UST location in the east end of the property. The test well, SP -1, will consist of a 1 -inch nominal diameter polyvinyl chloride (PVC) casing with a 2 -foot screen at the bottom and will be installed between MW4-RS and VW2-D to approximately 50 feet bgs (see Figures 4 and 5). Based on the lithologic interpretation of subsurface soil (as shown on Figure 3) within the treatment area, this test well should also be screened in the sandy portion of the shallow groundwater aquifer, in the area where the highest concentrations of petroleum hydrocarbons have been consistently found. Existing and newly installed monitoring wells located on the site property around the test well will be used as observation wells for monitoring during the pilot test. Wells considered primary observation wells for the pilot test are MW-4RS, MW -7S, VW -2D, VW -2S, and VW -3S. The groundwater wells, all within 20 feet of the test well, are screened within the depth interval of the biosparge well and also located mostly downgradient. Data from MW-4RS will provide additional information on DO distribution should DO increase be detected at an upgradient well. Data from VW -2S and VW -3S will provide information on the movement of volatile organic compounds in vadose zone potentially caused by biosparging. Additional (or secondary) observations will be taken from MW -8I, MW -IID, MW-4RD, and VW -IS (wells more than 20 feet away) to assess potential impacts of biosparging on the hydrocarbon plume at a distance. Data from these wells may be used to help determine the remediation well layout and placement. The locations of all these wells are shown on Figure 4. 4.1.2 Air/Oxygen Supply Equipment and Process Piping A portable, industrial -grade air compressor system will be used as the air injection source for the biosparge test. The air compressor will be an oil -less unit equipped with instruments, controls, and safety relief devices for safe operation of the equipment. The compressor capacity will be at Biosparge Pilot Test Final. doc 4-1 Shaw Environmental, Inc.