ARCHIVED REPORTS_XR0007378 CASE 2

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UNDERGROUND STORAGE TANK REMOVAL AT&T MICROWAVE RELAY FACILITY LODI,CALIFORNIA UST contents in order to solidify them and removed the contents from the UST with an excavator These contents totaled approximately SO cubic yards were placed In three stockpiles designated SP1, SP2, and SP3 The UST was not rinsed by Kvaerner prior to Its removal 43 UST and Piping Removal Procedures Kvaerner commenced soil excavation on January 27, 1999 An excavator was used to remove approximately 230 tons of soil from above and around the UST Soil was placed on visqueen on the ground to the east of the UST and was designated soil stockpiles SP4, SPS, SP6, and SP7 Product piping was disassembled and removed from the excavation by Kvaerner Approximately 100 pounds of dry Ice were added to the UST on March 4, 1999 A Lower Explosive Limit (LEL) meter was used to monitor vapor concentrations in the UST, and to ensure that the interior atmosphere did not exceed 10 percent of the lower explosive limit The UST had LEL readings of zero percent at the time of removal, with an oxygen concentration of 10 percent Cables were then attached to tank-Iift eyelets at the ends of the UST, and the UST was removed from the excavation with an excavator Residual soil was removed from the UST exterior surface to facilitate inspection for evidence of holes or leaks 44 Transportation and Disposal of 15,000-Gallon UST and Piping UST removal operations were performed on March 4, 1999 ECl/Enckson Inc transported the UST and piping to the ECl/Enckson tank cleaning facility in Richmond, California under a uniform hazardous waste manifest Copies of UST disposal documentation are is presented in Appendix B Followmg cleamng, the UST and piping were recycled as scrap metal 45 Collect Confirmatory Soil Samples ATC collected a total of six confirmation soil samples, and seven composite stockpile soil samples that were submitted for analytical testing on March 4, 1999 Five confirmatory soil samples designated E- 11 5', NW-13 5', SW-15', S-16', and N-16', were collected in the base of the UST excavation at depths ranging from 11 5 feet bgs to 16 feet bgs One sample designated PIPING-3 5' was collected beneath the product piping at a depth of 3 5' feet bgs Seven soil stockpile samples were designated SPI through SP7 Sampling locations are shown on Figure 3 and laboratory analytical results are presented in Table 5-1 The maximum depth of the tank vault was approximately 16 feet bgs Soil samples were collected as outlined in Appendix D • ATC Associates Inc 61059 0029 3