Laserfiche WebLink
1 t <br /> • Remedial System Enhancement Pian—Former Tosco(Unocal)Service Station No 6981 <br /> August 8,2001 <br /> CONCLUSION Excavation was performed during station demolition Site is <br /> primarily a groundwater only site <br /> Option#3 -Groundwater Pump And Treat <br /> An aquifer pump test was conducted at the site in August 1992 ,The test data indicated that <br /> groundwater pump treat may be a viable option at the site, but the data was generated when <br /> groundwater was at approximately 57 feet bgs Groundwater is currently at approximately <br /> 28 feet bgs <br /> COST Medium to high _ <br /> ' f I <br /> TIME FRAME Long term <br /> ADVANTAGES 1) Potential for hydraulic control <br /> 2) Effective in removing dissolved hydrocarbons in groundwater <br /> DISADVANTAGES 1) Does not remediate'the capillary fringe <br /> 2) Probably a long term process <br /> . CONCLUSION Not effective remedial method for this site Dissolved hydrocarbon <br /> concentrations are too low for efficient operation of this technology <br /> Other remedial options are more feasible <br /> Option#4 -Vapor Extraction <br /> A vapor extraction system utilizing a catox unit has been in operation at the site since <br /> September 1994 The current VES has reached asymptotic levels,is operating in pulse mode, <br /> and is not removing any detectable concentrations of petroleum hydrocarbons The VES can <br /> be modified to operate using activated carbon as an absorption material in place of the catox <br /> unit Treatment effectiveness will not change <br /> COST Low (modification of abatement system) <br /> TIME FRAME Long term due to low hydrocarbon extraction rate <br /> ADVANTAGES 1) Can remediate capillary fringe soils <br /> 2) Can reduce dissolved concentrations in groundwater <br /> 3) System is currently in operation at the site <br /> DISADVANTAGES 1) Current VES abatement technology is not cost effective <br /> 2) Will not fully remediate groundwater beneath the site <br /> 14012410 4 <br />