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l I70 FEASIBILITY TESTING 71 Oxygen Injection Feasibility Study On June 21, 2004, SECOR conducted an oxygen injection test on oxygen infection well S-1 Approximately 150 cubic feet (ft) of oxygen ,was injected into well S-1 (Figure 2) for approximately 30 minutes Dissolved oxygen (DO) concentrations were measured with a DO meter equipped with a down hole probe in well S-1 before and immediately following completion of the injection test During the test, injection pressures and flow rates were recorded from the injection well and lower explosive limit (LEL) oxygen measurements were Icollected in S-1 and in adjacent wells EX-1 and MW-5 Prior to the injection test, DO concentrations in the S-1, EX-1, and MW-5 were 2 6 milligrams per liter (mg/L), 2 2 mg/L, and 0 4 mg/L, respectively After the injection test, DO concentrations did not significantly increase, DO concentrations in EX-1 and MW-5 increased only 0 1 mg/L each IBased on these measurements it was determined that the radius of influence for oxygen injection is less than 5 feet Oxygen injection is not a feasible remedial alternative for this site Field notes for the oxygen injection feasibility test are included in Appendix B 7.2 Groundwater Pumping Test The purpose of this test was to evaluate hydrogeologic Conditions beneath the site and to determine whether groundwater pumping from EX-1 is a feasible alternative for remediating dissolved petroleum hydrocarbons and MtBE in groundwater beneath the site Methodology Before beginning the step drawdown and constant rate pumping tests, pressure transducers ' with built-in data-loggers were installed in pumping well EX-1 and observation wells S-1 and MW-5 on August 11, 2004 to monitor water levels before, during, and after aquifer testing (Figures 2) The data-loggers were programmed to record water level depths at one-minute ' intervals A step-drawdown test was conducted on August 11, 2004 using a submersible pump in well EX-1 Before the start of the test, water levels in pumping well EX-1 and the two observation wells (S-1 and MW-5) were monitored EX-1 was subsequently pumped for a specified period at different pumping rates (steps) while monitoring changes in the water level in the pumping well The water levels and corresponding times were recorded during each step to I allow for analysis of the drawdown attributed to each step, and to provide information needed for the selection of an optimum pumping rate for the constant-rate pumping test The , optimum pumping rate is the highest pumping rate that will not draw the water level down to the pump over the duration of the constant-rate pumping test (approximately 24 hours) Based on the analysis of the step-drawdown test the constant-rate test was initiated on August 12, 2004 by pumping EX-1 at 0 8 gallons per minute (gpm) The objective of the test ' was to create hydraulic stress in the aquifer by pumping from well EX-1 at a constant + pumping rate while monitoring drawdown in observation wells S-1 and MW-5 After approximately 400 minutes of continuous pumping the constant rate test was stopped due to Ia shortage of fuel in the generator The lapse in pumping lasted approximately 10 minutes 32262 Assessment&Feasibility Report&SCM doe 10 September 30 2004 I77EL 32262 04 0502