Laserfiche WebLink
Mr.Nuel Henderson, R.G January 31, 2003 <br /> Installation of Ozone Injection System and Remediation Status Report <br /> • Page 2 <br /> was excavated from the north end of the western dispenser island. Approximately 60 cubic yards <br /> of soil and pea-gravel were excavated and removed from the site (IT, February 2000). <br /> Between June 5 and 8, 2000, six monitoring wells (MW-1 through MW-6) [see Figure 2]) were <br /> installed and the site was subsequently placed on a quarterly monitoring program. In response to <br /> the San Joaquin County Public Health Service Environmental Health Division (PHS/EHD) <br /> request for additional assessment to evaluate lateral and vertical impact of petroleum <br /> hydrocarbons to soil and groundwater, four additional monitoring wells(MW-7 through MW-10) <br /> were installed in May 2001. Further offsite assessment is pending access to adjacent properties. <br /> In an effort to evaluate ozone injection as a possible final remedial approach, five ozone injection <br /> points (IW-1 through IW-5) were installed (March 2002) and were connected as part of the <br /> interim remediation plan. <br /> OZONE INJECTION SYSTEM <br /> The primary objective of the ozone injection system is to initiate remediation of petroleum <br /> hydrocarbon impacted groundwater through chemical oxidation. A C-SpargeT"t system, <br /> consisting of an ozone generator and air compressor, are used to inject low concentrations of <br /> . ozone into groundwater through strategically located injection points (sparge points). The ozone <br /> dissolved in groundwater directly degrades petroleum hydrocarbons into carbon dioxide and <br /> water, and any unreacted ozone will degrade to dissolved oxygen to enhance natural <br /> biodegradation of residual petroleum hydrocarbons. The system injects a timed pulse of ozone at <br /> low flows and low pressures to each of the five sparge wells in a sequence. The timer limits the <br /> amount of ozone injected into each well, thereby maximizing contact between the ozone and <br /> petroleum hydrocarbons, and greatly reducing the possibility for ozone and petroleum <br /> hydrocarbons to be released to the environment. <br /> Installation of Sparge Points (Ozone Injection Wells) <br /> Injection points IW-1 through IW-5 were constructed and installed between March 25 and 26, <br /> 2002, using a 2-inch diameter by 30-inch length of microporous tubing installed at the base of <br /> each soil boring. Blank PVC casing (0.75-inch diameter) was connected to the microporous <br /> tubing and installed up to surface grade. The standard "O-rings" installed on the casing by the <br /> manufacturer(Boart Longyear) were replaced with VitonT"` 0-rings to resist possible degradation <br /> by ozone. A filter pack of LonestarTM #2112 sand was placed around the microporous tubing <br /> from the base of the boring to approximately one foot above the top of the microporous tubing. <br /> Bentonite was placed on top of the filter pack to provide a sanitary seal for the well. The boring <br /> was subsequently backfilled with neat cement up to surface grade. A 12-inch diameter traffic <br /> rated vault box was placed over the top of each well. <br /> PA3p-Arco for URSI54691ReportAArco 5469 Remediation Status Report.doc 5TRAru5 <br />