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CTO&g`ZrA1 Tedluua 1Ac. Page 7 <br /> Dual Phase Extraction Pilot Test Report <br /> Project No 723 2 <br /> November 12, 2004 <br /> A final groundwater sampling event was conducted on July 8, 2004 two weeks after the last <br /> ' injection event <br /> Photographs of the field activities are included in Appendix E <br /> ' • Photograph#1- Close up of well configuration <br /> • Photograph#2- Purging well GP-2 using Waterra system <br /> • Photograph#3- Pumping hydrogen peroxide from 5-gallon container into well MW-9 <br /> • Photograph#4- Pumping from truck mounted ozone generator into well MW-9 <br /> The groundwater samples obtained from MW-9, GP-1, GP-2 and GP-3 during the test were <br /> submitted to Sherwood Labs (Department of Health Services Certification No 1400) of <br /> Hilmar, California, for analysis The samples were analyzed for <br /> ' • Benzene, Toluene, Ethyl Benzene and Xylene (BTEX) & MTBE by EPA method <br /> 8020 <br /> • Total Petroleum Hydrocarbons as Gasoline (TPH-G) by EPA method 5030/8015(M) <br /> ' The groundwater laboratory data are included in Appendix C and summarized in Table 2 <br /> Summary of Groundwater Analytical Data(Appendix A) <br /> 5.0 DATA ANALYSIS <br /> The purpose of the pilot test was to determine if in-situ chemical oxidation (ISCO) is an <br /> effective technology to remediate the gasoline impacted soil and groundwater at the site The <br /> ' parameters indicating the effectiveness of the test are the reduction in contaminant mass and <br /> the radius of influence of the oxidant injection point The mass destruction and radius of <br /> influence can be utilized to develop a full scale corrective action plan (CAP) to address the <br /> entire contamination at the site The following sections will discuss the data obtained for <br /> these two parameters during the test <br /> ' 5.1 Contaminant Destruction <br /> ' The contaminant concentrations listed in Table 2 in Appendix A did show evidence of being <br /> affected by the oxidant injection in well MW-9 <br /> Hvdrozen Peroxide M02} <br /> Injection well MW-9 showed predicable results <br /> o The concentrations of TPH-G from Table 2 are plotted in Figure 3 The TPH-G <br /> ' concentration in MW-9 showed an immediate response to the first hydrogen peroxide <br /> injection on March 19 by falling from 137,000 µg/1 to 117,000 ug/l on April 2 The <br /> TPH-G in this well remained lower (64,000 — 71,000) for the next four sampling <br /> 1 <br />