Laserfiche WebLink
May 4, 1993 Working To Restore Nature <br /> Unocal Station No 6981, Stockton, California <br /> 5.0 EVALUATION OF REMEDIAL ALTERNATIVES <br /> 5 1 Selection Criteria <br /> The criteria used to evaluate potential remedial options for the site include relative <br /> effectiveness, treatment time and time constraints, cost, and future liability Soil <br /> remediation options considered include excavation and vapor extraction Ground-water <br /> remediation options considered include no action/monitor, and ground-water extraction and <br /> treatment <br /> 52 Soil Remediation Options <br /> 5.2.1 Excavation <br /> I <br /> Soil with residual gasoline hydrocarbons occurs beneath the tanks and the dispenser islands <br /> at depths to approximately 55 feet or the top of ground water Because of the depths, <br /> proximity to existing structures, and the proximity of two major roads, these conditions are <br /> not conducive for removal of all hydrocarbon containing soil by excavation Furthermore, <br /> this alternative would require the removal of the fuel UST's, the cashiers booth, and both <br /> dispenser islands RESNA estimates that if the soil could be excavated without structurally <br /> 1 compromising the two roads and the adjacent parking lot, over 6,500 cubic yards of soil will <br /> require treatment onsite by either uncontrolled aeration or vapor extraction of soil <br /> stockpiles, direct disposal without pre-treatment is also an alternative <br /> 1 <br /> 5.2.2 Vapor Extraction <br /> Based on the results of the site assessment and vapor-extraction test, (RESNA, December <br /> 16, 1992, RESNA June 29, 1992) vapor extraction of gasoline hydrocarbons from the <br /> 38032-13 10 <br />