Laserfiche WebLink
r <br /> OOtOgual Teelaaes lxr- Page 6 <br /> Dual Phase Extraction Pilot Test Report <br /> Project No 662 2 <br /> February 22, 2005 <br /> rneat cement grout (augmented with <5% bentonite) into the borehole through a PVC tremmie <br /> pipe The well was secured with a locking watertight cap encased in a flush mounted traffic <br /> rated well box <br /> The well construction details are shown in Appendix A, Table 2 and on the boring logs <br /> ' included in Appendix B <br /> 3.2 Well Development <br /> GTI staff mobilized to the site on November 8, 2004 to develop the new well EW-2 The <br /> well was developed by surging and pumping with a dedicated Waterra pump system The <br /> well was pumped dry after 8 gallons was removed All purge water was contained on site in <br /> drums while awaiting disposal <br /> ' 3.3 Well Survey <br /> ' The new extraction well was ,urveyed at the same time as the new monitoring wells as <br /> detailed above in section 2 5 <br /> 4.0 MOT TESTS <br /> ' Soil vapor and groundwater extraction are two proven technologies for the remediation of <br /> gasoline impacted sites Dual Phase Extraction (DPE) involves the use of both technologies <br /> simultaneously from one well - extracting groundwater induces a cone of depression that <br /> ' exposes more impacted soil to vapor extraction GTI utilized the services of Mako Industries <br /> (Mako) of Pleasanton, California to provide equipment for the extraction test Mako <br /> provided a portable trailer comprised of a vacuum blower, a liquid ring pump to separate <br /> ' water/soil vapors, a thermal oxidizer to treat extracted vapors, and manifolds to distribute <br /> vacuum among various extraction hoses A Mako subcontractor provided a propane tank for <br /> fuel to operate the thermal oxidizer and American Valley provided a trailer for use as an <br /> ' extracted groundwater holding tank <br /> ' The general process for the dual phase extraction was as follows <br /> ■ Remove vapors and groundwater from the extraction well(s) using the vacuum pump <br /> capable of producing >21 inches of mercury vacuum The vapors and water were drawn <br /> ' out of the well(s) through a stinger set at the desired depth for extraction <br /> ■ The influent vapors and water were separated in a portable vacuum tank <br /> ■ The contaminated vapors were then extracted through a liquid ring pump and oxidized in <br /> ' a thermal oxidizer <br /> ■ Collect data for vacuum flow and contaminant concentrations and temperature <br /> r <br />