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i <br /> Atlantic Richfield Company 5 <br /> ARCO Service Station 4932 16 Fat Harding Way,Stockton A May 10200t <br /> SUMMARY OF FINDINGS <br /> • <br /> 1 On February 12-16, 2001, SECOR performed NTE feasibility testing at the site to <br /> evaluate whether MPE technology is a feasible remedial alternative for mitigating <br /> hydrocarbon-impacted soil The results of the feasibility test are as follows <br /> 1 • The MPE test was conducted at maximum vapor extraction flow rates <br /> ranging between 32 7 to 99 2 scfm (MW-4/SVE-1), and at vacuum pressures <br /> ' ranging between 5 5 to 25 inches of water column (MW-41SVE-1) <br /> Induced vacuum readings were observed in observation wells up to 89 feet <br /> ' away from the extraction well Based on the responding induced vacuums, <br /> the radii of influence for the test ranged between 46 7 feet and 89 2 feet <br /> ' • Field FID readings of total hydrocarbons in the vapor stream extracted from <br /> the test wells consistently exceeded 10,000 ppmv During the test <br /> approximately 544 3 pounds of TPHg, 19 5 pounds of benzene, and 440 <br /> 1 pounds of MtBE were extracted from the soil beneath the site <br /> 1 CONCLUSIONS AND RECOMMENDATIONS <br /> Based on the data collected during the NTE test, MPE technology is capable of <br /> 1 removing high concentrations of hydrocarbons from the soil beneath the site <br /> The estimated daily mass removal rates following the initiation of vapor <br /> extraction range from 18 to 26 pounds of TPHg and up to 62 pounds of MtBE <br /> While the rate hydrocarbon removal is expected to decline over time, the <br /> multiphase extraction would significantly reduce the mass of petroleum <br /> hydrocarbons present in the subsurface <br /> ' Based upon the above data and data from the SECOR's First Quarter 2001 <br /> Quarterly Monitoring Report, SECOR recommends that the additional site <br /> ' assessment previously proposed to further evaluate the extent of the MtBE <br /> plume (SECOR - January 5, 2001)be performed prior to preparation of a <br /> remediation plan for the site <br /> ' This report presents our understanding of existing conditions at the subject site The <br /> conclusions contained herein are based on the analytical results and professional <br /> ' judgment, which are in accordance with current standards of professional practice, no <br /> other warranty is expressed or implied SECOR assumes no responsibility for <br /> exploratory borings or data reported by other consultants or contractors <br /> 1 <br /> 1 <br /> i <br /> ' ARCO 49321MPE test doc <br />