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3.8 Well Development <br /> As per the requirements set forth in the November 24, 1998 PHS-EHD letter, groundwater <br /> monitoring well MW-7 was surged with a surge-block and purged with a development ng until values <br /> of temperature, conductivity, and pH had stabilized, and the effluent was clear Surging and bailing <br /> well MW-7 resulted in increased groundwater yields, indicating that the well does not require <br /> replacement In addition, newly installed well MW-12 was surged and developed using the same <br /> methodology A total of five(5)well casing volumes of groundwater were removed from each well <br />' at a rate of approximately 2 gpm Purged groundwater was pumped into an on-site Baker tank for <br /> future treatment by Sun-Ag <br />' 3.9 12-Hour Pump Test <br /> A 12-hour groundwater extraction test was performed by Park on monitoring well MW-11 (located <br />' in the UST pit)to evaluate the Site for potential groundwater extraction remediation as required by <br /> the PHS-EHD The test was originally scheduled for a duration of 24 hours, however, steady-state <br /> groundwater levels were achieved in the groundwater extraction and observation wells after 6 hours <br /> of extraction Park continued operation of the groundwater extraction test for an additional 6 hours <br /> and consulted with Thnfty personnel prior to discontinuing testing Specific items completed as part <br /> of the extraction pilot test were as follows <br /> Extraction of groundwater from groundwater monitoring well <br /> • gr <br /> MW-11, <br /> • Monitoring responses of the tested and adjacent wells during the <br /> 12-hour groundwater extraction test to evaluate groundwater levels, <br /> • Analyzing the groundwater samples for TPH, BTEX, and MTBE <br />' using EPA Methods 8015M(modified for gasoline), 8020, and 8260, <br /> respectively, <br /> • Evaluating the results of the pump study test <br /> 3.14 Extraction Well Groundwater Sampling <br /> Groundwater samples were collected from extraction well MW-11 prior to, and immediately after <br /> groundwater extraction testing Groundwater samples were collected using a new, disposable bailer <br />' and placed in the appropriate laboratory-supplied containers The samples were labeled with date, <br /> time, identifying well number, sample name, and project name The groundwater samples were <br /> placed in an ice-chilled cooler and transported to the laboratory under proper chain-of-custody <br />' documentation <br /> 1 <br /> A.11528I1 ASA 9 <br /> 1 <br />