ARCHIVED REPORTS_NOTICE OF INTENT FOR INSTALLATION, OPERATION AND MAINTENANCE OF AN OZONE INJECTION GROUNDWATER REMEDIATION SYSTEM

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' Each oxidation point was suspended approximately 10 feet below the groundwater surface by V2-inch- diameter Teflon"' tubing connected to a threaded cap with stainless steel compression fittings. Wells AS-1 through AS-5 each had a dedicated line individually connected to the OS System by 1/2- ' inch-diameter TeflonTM tubing. The OS System cycled injected ozone/air between the five sparge points approximately 29 times per day for 7 minutes per point per cycle for the duration of the test(90 days).Each cycle was followed by a 15-minute rest period. On January 29, 2009, we turned on the OS System and began sparging oxygen to assess that the system was functioning properly, that the compression fittings and tubing connections were leak free and that acceptable pressures could be sustained for each of the selected injection wells. The oxygen only sparging continued until OS began on February 9, 2009. 2.3 OS Activities ' We performed the OS pilot testing activities at the Site from February 9, 2009, to May 11, 2009, during which we monitored the OS System twice weekly. Details of the observed injection rates in standard cubic feet per minute (scfm) and delivery pressures in pounds per square inch (psi) in addition to the total ozone injection time to each well in minutes are summarized in the following ' table. Injection Rate Delivery Pressure Total Ozone Injection Well ID Valve(s) ' (scfm) (psi) Time (min) AS-1 6, 8 1.6 to 1.8 16 to 25 15,509.8 AS-2 2 1.6 to 1.8 16 to 24 15,946.7 ' AS-3 3, 11 1.4 to 1.8 18 to 40 16,575.0 AS-4 4 1.4 to 1.8 21 to 38 16,983.4 AS-5 5 1.6 to 1.8 17 to 26 16,356.1 The valves connecting the OS System to wells AS-2 and AS-3 were switched on April 2, 2009, due to faulty solenoids within the OS System panel. Differences in total ozone injection time were primarily due to ozone detections inside the OS System which triggered the system to switch the active valve at ' the time of the detection from sparging ozone to sparging oxygen. ' On March 26, 2009, the sparge points within the two sparge wells closest to the former USTs (AS-2 and AS-5) were lowered to depths of 50 and 55 feet, respectively. The original depth for both sparge ' points was 40 feet below the wellhead. The sparge points were lowered to approximately 2 feet above the bottom of the well to position the sparge points closer to the screened interval of both wells allowing better ozone infiltration into the subsurface. Project No.S9183-06-02 -4- July 2,2009 1