ARCHIVED REPORTS XR0009987 - Laserfiche WebLink

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i Groundwater is anticipated to flood the excavations The excavations will be allowed to flood twice and be pumped out twice to remove contaminated water and allow, "back flushing" of dissolved contaminants The water will be stored in surface tanks, or pumped directly to vacuum trucks depending upon the operational constraints of the site Verification soil and groundwater sampling will be collected and analyzed for TPHG, BTEX and MTBE and oxygenates Soil samples will be collected at 20-foot mtervals along the capillary fringe to ascertain presence or absence of contaminants A groundwater sample will be collected from the flooding following the second dewatering to ascertain dissolved contaminants presence Samples of the contaminated groundwater and soil will be collected allowing judgment of contaminant mass removal to be estimated Wright excavated two locations to approximately 12 feet below ground surface to obtain contaminated soil samples (see Figure b for locations) and to assess the feasibility of using heavy equipment safely and effectively in close constraints to the irrigation pipeline present Wright was able to determine that the irrigation pipeline is old and very fragile Any use of heavy equipment near the pipeline would pose an inherent risk of pipe damage Also, West Side Irrigation District (owner of the pipeline) has indicated that due to the nature of its use during sprang and summer months the only window of opportunity to excavate around at would be during the winter months when the pipeline as not in use, which is an unfavorable situation Ntiation of tins clean up option would commence after obtaining the following approvals and permits • Approval of this CAP b PHS-EHD PP Y • A City of Tracy Building Permit • Pre-Approval of clean up costs from UST Clean up Fund (USTCF) • Relocation plan for affected tenants at current property owner • Wntten approval from Irrigation District and approved window to work around irrigation pipeline The cost for Option 1 is estimated to be S 335,000.00. The pricing is inclusive of(4) Quarters of follow up Groundwater Monitoring A spreadsheet of estimated costs is provided as an Appendix A However, tenant relocation costs and replacement of subsurface utilities may well exceed the projected, estimated costs Option 2 Soil and Gro dwater Dual Phase Extraction Given the type of soil and shallow groundwater occurrence a combined Dual Phase Extraction (DPE) soil vapor and groundwater extraction for the remediation of hydrocarbon-containing soil is possible This approach could target the areas of interest without the disruption of a Iarge soil excavation, relocation of trailers and tenants, utilities and eliminate the need for off-sate disposal costs The system is flexible and can be modified and adjusted as system results and periodic system sampling as performed These systems have a trach record of successful performance and the site has sufficient area for locating the surface treatment system The option assumes an 18-month duration Page 12