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Treadwell&Rollo <br /> • <br /> Area 15 <br /> The current owners of Area 15 have proposed to perform additional remediation, as outlined in a <br /> 10 February 2000 letter to Mr. Jeff Wong of SJCEHD. These tasks include the following: <br /> 1. Excavate approximately 150 cubic yards of soil from the area of former UST#1 to <br /> remediate soil contaminated with total petroleum hydrocarbons as gasoline (TPH-g) and <br /> diesel (TPH-d). <br /> 2. Perform a groundwater pumping test at the location of former UST#8 to determine if <br /> groundwater extraction is a viable treatment approach to deal with contaminated soil and <br /> groundwater at that location. TPH-g and TPH-d have been found at this location at up to <br /> 8,800 mg/kg. <br /> An alternative approach which could be taken by the SDHR would be to excavate the shallow <br /> soil contamination at former UST#1,but to remediate the more extensive soil and groundwater <br /> • contamination at former UST#8 by ozone sparging. The estimated costs to perform this work <br /> are as follows: <br /> 1. Excavate and dispose of soil at former UST 1 —$30,000. <br /> 2. Install five ozone sparge wells with sparging system—$100,000. <br /> The recent RI report cited the presence of petroleum hydrocarbons in soil at 15B-4, 1513-6, and <br /> 15B-9, at 1 to 15 feet below grade. Excavation and disposal of 1,500 tons of soil from this area <br /> could cost approximately $112,500 to $187,500, depending on whether shoring would be <br /> required. Alternatively, an ozone sparging system could be installed for approximately $70,000, <br /> plus operations and maintenance. <br /> Area 16 <br /> An extensive soil vapor extraction and air sparging system is currently operating at Area 16. The <br /> property owner has stated that the system may be expanded to expedite the soil and groundwater <br /> • remediation program. If the SDHR acquires the site, it is recommended that this system continue <br /> 41 <br /> 25970318.PGS 15 November 2000 <br />