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07 February 2008 AGE-NC Project No. 96-0254 Page 3 of 5 that the method seldom achieves regulatory goals for ground water clean-up. Systems typically operate for several years (four years). During this time, pumps and other equipment may need replacement several times. Currently, the primary utility of pump-and-treat systems is to control migration of contaminated ground water and reduce the dissolved contaminate concentrations (BTEX) to level which meet water quality objective; or to reduce the dissolved concentrations to level which should naturally degrade to water quality objective. Discharge of treated ground water at the site into the City of Tracy Sanitary Sewer system would be required throughout the duration of the remediation.A ground water extraction feasibility proposed for the site 300 feet south(Tracy Marine Sales at 2353 Toste Road)was not performed, in preparation of an alternative remediation technology (explanation in Section 2.2.). 2.1.4. Cost Ground water extraction is usually a very costly method of ground water treatment. The cost for installation of a"pump and treat" system typically ranges from $85,000 to $95,000, including the installation of large-diameter extraction wells. Once extracted, the contaminated water must be treated or disposed. Treatment is highly dependant upon the concentrations of dissolved petroleum hydrocarbons in the ground water; the cost per gallon could be as great as $0.15 based on the extraction/treatment of approximately 3,000,000 gallons of contaminated ground water;with the cost entire treatment project would likely be between $400,000 and$450,000. 2.2. 17V--SITU CHEMICAL OXIDATION/OZONE SPARGING The ozone sparge system is an in-situ air stripping and in-situ chemical oxidation process utilizing fine bubbles of ozone injected into saturated soil to extract and decompose dissolved petroleum hydrocarbon constituents.An ozone generator is utilized to produce gaseous ozone which is injected into the subsurface via microsparge points or fine well screen.The"microbubbles"(approximately 50 micro) are forced out into the surrounding saturated soil and react with the target analytes, producing carbon dioxide and water. The frequency and duration of ozone injection periods can be regulated at the ozone generator control box. Initially,operation of the ozone injection system will be based on the manufacturer's recommendations. Injection rates, frequency, and duration may be adjusted to compensate for site conditions during a pilot test, based on dissolved concentration reaction to the sparging,ground water flow direction changes,and to reduce mounding of the ground water wwzc necessary. Advanced GeoEnvironmental,Inc.