COMPLIANCE INFO_FILE 8 - Laserfiche WebLink

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Supplemental Information The 827-D2U1 tank system was installed in 1967 at the southeast comer of Building 827A. It supplies diesel fuel to an emergency generator for Building 827A. The tank system consists Of a 280-gallon,single-walled,carbon iiteel,underground storage tank( associated fill t pipe,and fuel supply and return piping. Pipingclosed in within and beneath concrete will be place. All remaining accessible piping will be removed. The area is unpaved,but is compacted and gravelled. The emergency generator,and its associated UST,827-D2U1,are currently in use. The emergency generator will be supplied by a temporary aboveground fuel tank prior to the removal of UST 827-D2U1. UST 827-D2U1 will be replaced by a new 250-gallon aboveground diesel fuel storage tank. The system was registered with the State Water Resources Control Board in 1984 as 827-12D and has subsequently been renamed 827-D2U 1. Figure I (see Appendix B)shows the location of the 827-D2UI tank system in relation to the Lawrence Livermore National Laboratory (LLNL),Site 300. Figure 2(see Appendix B)shows the 827-D2UI tank system in relation to Building 827A. Figure 3(see Appendix B)shows a plan view of the 827-D2UI tank system. UST 827-D2U I has not leaked according to previous tank testing reports. LLNL had contracted with the Gary Peters Enterprises to perform precision tank tests using the Tank Audit LEAK COMPUTER on this underground diesel fuel storage system for the past 4 years. The most recent test results,from Clayton Environmental Consultants using the Homer EZY- CHEK method,are included as Appendix C,and show the tank and piping to be product tight. If minor soil contamination is found when the tank is removed,LLNL will remove up to 10 cubic yards of suspected contaminated soil.The underlying soil will then be sampled to determine if any contamination is remaining in the soil. Soil contamination that appears to be More than minor,or indication of contaminated groundwater,will result in further investigation and cleanup activities as agreed upon with San Joaquin County,Public Health Services. Any contaminated soil removed from the excavation will be stored,sampled,and disposed of properly. Water samples from the groundwater monitoring wells near 827-D2U1 (see Figure 4)are not currently analyzed for diesel fuel. If soil contamination is found,and if there is reason to suspect that the contaminants have migrated from the area,groundwater samples from the monitoring wells could be analyzed for diesel fuel. However,groundwater contamination is not expected due to the tank integrity and the depth to groundwater of approximately 60 feet. Figure 4 shows the location of a"dry well"and its associated underground piping. A dry well is a shallow,earthen depression,filled with gravel,used to drain away non-hazardous building effluent. Due to the fact that the first water-bearing zone in the area of Building 827A is discontinuous, inferred groundwater contours could not be presented on Figure 4. It is presumed that the groundwater in the area flows south-southeast. Only dime groundwater monitoring wells in the area are screened in the first water bearing zone. Of these,two are located approximately 1400 feet upgradient of the UST removal projeCt. The location and groundwater data of the one downgradient well,designated W-827-02,is shown on Figure 4. A State Water Resources Control Board Underground Storage Tank Permit Application-Form B will be completed and sent to San Joaquin County,Public Health Services-Environmental Health Deparm-ctit once UST 827-D2U1 has been removed. A-1