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Jeff Won EH <br /> A _ 1 <br /> From: Donna Sexton [dsexton@advgedenv.com] <br /> Sent: Monday, June 27, 2005 1:07 PM'- <br /> To: Jeff Wong [EH] <br /> Cc; Nuel Henderson [EH] <br /> Subject: Stefano's Ozone Study-continuation <br /> Stefano's Ozone Stefano's Table 2 <br /> Pilot Test-ta... ground water... <br /> Jeff, <br /> I am in the process of gathering and interpreting the data for the study. <br /> At this juncture 1 recommend the continuation of the system until the <br /> report is complete (it is in review) . The initial data indicates the system <br /> is successful and is reducing the amount of dissolved TPH-g and 1,2-DCA. I <br /> am attaching the tables for the analytical data and the ORP/DO numbers. <br /> Here are some preliminary conclusions. <br /> Based on the findings from this investigation: <br /> Dissolved Oxygen measurements ranged from 0.57 mg/l in. well MW-2 to 14 .30 <br /> mg/l in well MW-3. DO measurements in well Mod-3 averaged 10. 98 mg/l <br /> indicating that ozone from the injection wells is effecting the ground <br /> water surrounding MW-3. The ozone injection is oxygenating the ground water <br /> in the area of well MW-3 which will also lead to enhanced aerobic <br /> biodegradation. <br /> Oxidation-Reduction Potentials (ORP) were measure on a' regular basis to <br /> monitor the potential for oxidation of the petroleum hydrocarbons present <br /> in the ground water. Throughout the pilot study the ORP`$ steadily <br /> increased from negative to positive in most monitored we11s. <br /> Based on the analytical data acquired over the 24-week pilot test it would <br /> appear that petroleum hydrocarbon concentrations have decreased in the area <br /> of ozone injection. Concentrations of petroleum hydrocarbons have decreased <br /> to non-detect in wells MW-1 and MW-3. The February to June 2005 sampling <br /> events were the first time since 1999 that TPH-g was not , consistently <br /> detected in well MW-3. In addition, the Junes:2005 event was the first time <br /> that TPH-g significantly decreased in well MW-2 since ozone injection <br /> began. <br /> 1,2-DCA concentrations detected in well MW-3'lhave decreased throughout the <br /> pilot study from a high of 29 Fg/l in February 2005 to a loes of 5.7 Fg/l in <br /> June 2005. <br /> I will continue to run the system until I am otherwise. directed not to by <br /> EHD. <br /> i; <br /> Donna Sexton <br /> Advanced GeoEnvironmental, Inc. <br /> 837 Shaw Road ; <br /> Stockton, CA 95215 <br /> Phone: (209) 467-1006 <br /> Fax: (209) 467-1118 <br /> dsexton@advgeoenv.com <br /> www.advgeoenv.com <br /> L . <br />