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4 , <br /> } k w <br /> Ozone Microsparge Well and System Installation Report—Former Tosco(Unocal)Service Station No 6981 <br /> February 1,2002 <br /> Soil cuttings generated during drilling were placed on and under visqueen at,the site pending <br /> transportation to an appropriate landfill <br /> Ozone Micros are Well Installation <br /> Ozone mtcrosparge wells SP-1 through SP-13 were constructed using 1/a-inch diameter Schedule 40 <br /> polyvinyl chloride (PVC)casing and a 2 5-foot long by 2-mch diameter air ozone mtcrosparge point <br /> The annular space around the well screen was packed with Lonestar #60 sand to approximately 2 5 <br /> feet above the top of the well screen The sandpack of each well was followed by a 3-foot thick <br /> hydrated bentonite transition seal and then neat cement to the surface Well construction details are <br /> included with each of the boring logs presented in Appendix B <br /> CHEMICAL ANALYTICAL RESULTS <br /> One composite soil sample from the soil stockpile was collected and submitted for chemical analysis <br /> Analyses were performed by Sequoia Analytical of Petaluma, California (ELAP #2374) Copies of <br /> the laboratory reports and chain-of-custody forms are included in Appendix C <br /> Chemical Analytical Procedures <br /> The soil samples from soil stockpile was analyzed for TPHg, benzene, toluene, ethylbenzene and <br /> xylenes (BTEX), and methyl tert-butyl ether (MtBE) according to Environmental Protection Agency <br /> (EPA)Method 5030/8015/8021 and total lead by EPA Method 6010B <br /> Soil Chemical Analytical Results <br /> The soil stockpile sample was reported as not detected for TPHg, benzene, toluene, ethylbenzene, <br /> MtBE, and total Iead, and contained 0 0053 ppm of xylenes <br /> WASTE DISPOSAL <br /> A total of 17 18 tons of drill cuttings were removed from the site on December 4, 2001, and <br /> transported by Tim Manley Trucking, Inc to Forward Landfill in Manteca, California The Forward <br /> f disposal confirmation letter is included in Appendix D <br /> REMEDIAL ACTION <br /> _ As an enhancement to the existing remedial action system at the site, GR installed an ozone <br /> microsparging system Ozone microsparging is a process where ozone in air is introduced into the <br /> groundwater at low flow rates (2-6 cubic feet per minute) through specially designed spargers to <br /> create small "microbubbles" As these microbubbles rise within the column of water, they strip and <br /> rapidly oxidize VOCs from the groundwater <br /> 140124 12 <br /> 4 <br />