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v <br /> Wriiht <br /> ■ Environmental <br /> August 13, 2003 Services, Inc. <br /> Project No. 4233-3 67 E. 10'" Street, Tray, CA 95376 <br /> Ph:209-833-0758 Fax:209-832-5152 <br /> Trust of Mary Gardella <br /> 5252 d Street <br /> Santa Cruz, California 95060 <br /> Attn.: Ms. Winifred Alexander <br /> Re: Workplan for Ozone Injection <br /> Stefanos Gasoline 1419 Charter Way, Stockton, CA <br /> Dear Ms. Alexander, <br /> Ozone injection has been proposed as an interim remediation measure to clean up <br /> petroleum hydrocarbon impacted ground water at the subject site (Figure 1- Location <br /> Map). This workplan describes the proposed installation of an ozone injection <br /> remediation system. New ground water monitoring wells associated with this site will be <br /> installed as described in a workplan (Wright 2003a) approved by the San Joaquin <br /> Public Health Services Environmental Health Division (PHS EHD). <br /> Ground water monitoring data(Ramage 2003, Wright 2003b) show that the known extent <br /> of the ground water plume is centered on well MW-2 (Figure 2- Site Map). The highest <br /> concentrations of chemicals of concern(CDCs) including TPH-G, BTEX, 1,2 DCA and <br /> fuel oxygenates occur at depths of 35 to 50 feet in site ground water, although COCs <br /> have been detected in discrete cone-penetrometer samples taken at depths of up to 115 <br /> feet (Ramage 2003). <br /> Ozone Remediation System--Process Description <br /> Conceptually, ozone injection long employed in the wastewater industry, works on the <br /> principles of stripping and chemical oxidation. A mixture of compressed air and ozone is <br /> injected into the subsurface through pipe sections made of micro-porous plastic or <br /> ceramic material. This process releases a cloud of uniformly sized micro-bubbles of <br /> air/ozone that spread out into the aquifer. Dissolved volatile organic compounds (VOCs) <br /> are stripped within the micro-bubbles i.e_ transferred from the dissolved to the vapor f <br /> phase, and then chemically oxidized--often completely to carbon dioxide and water. <br /> Halogenated compounds can be oxidized to carbon dioxide, water and the halogen. Even <br /> if not stripped, both volatile and non-volatile organic substances can be oxidized by <br /> reaction with ozone in the dissolved phase. In addition, the sparging process raises the <br /> dissolved oxygen content of the ground water aiding microbial biodegradation of <br /> dissolved hydrocarbons. <br /> 4 <br />