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I <br /> ' CA3,- ADDRrSS lI C <br /> SEATTLE 'E FAX) 205 283 8036 <br /> TACOMA N <br /> PORTLAND <br /> STOCKTON 112 , To <br /> RENO ^ a TIME OIL Cr, <br /> RICHMOND o <br /> LOS ANGELES 4 � e �f <br /> 5 TS 2737 WEST COMMODORE WAY SEATTLE WA 98199 1233 <br /> PROD ucis M P Q BOX 24447 SEATTLE,WA 98124-0447 <br /> TIME TESTED E <br /> May 29, 1998 <br /> Mr Harlin Knoll <br /> San Joaquin Co,mty Public Health Services <br /> Environmental Oealth Division <br /> P O Box 2009 <br /> Stockton, California 95201 <br /> RE Submittal of"Vapor Extraction Feasibility Testing" Report for <br /> Jackpot Food Mart, 14000 Er Highway 88, Lockeford, California (Property No 04-049) <br /> Dear Mr Knoll, <br /> At the request of the San Joaquin County Public Health Services Environmental Health Division (PHS/EHD), <br /> an additional environmental investigation was implemented at the subject site in December 1994 to evaluate <br /> the extent of hydrocarbon-impacted sods and to determine whether or not groundwater had been impacted <br /> A total of four groundwater monitoring wells were installed dunng this investigation In July 198(3, six <br /> additional groundwater monitonng wells were installed on and off of the subject site to assist in defining the <br /> extent of groundwater Impacts In general, soil and groundwater impacts have been defined <br /> A pilot test was conducted at the $ubject site in March 1998 to determine if vapor extraction is feasible for <br /> addressing hydrocarbon-impacted $oils associated with the former underground storage tanks Please find <br /> enclosed a copy of SECOR's "Vapor Extraction Feasibility Testing" report dated May 27, 1998, which <br /> contains the results of the pilot test Prior to the initiation of site work, SECOR's "Work Plan for Soil Vapor <br /> Extraction Pilot Test" dated June 26, 1997, was forwarded to the appropriate regulatory agencies Approval <br /> of the workplan was received from the County on October 6, 1997 Pre-approval of costs for a 2-day pilot <br /> test was received from the Cleanup Fund on January 15, 1998 <br /> For your convenience a summary of previous site activities is attached <br /> Vapor Extraction Feasibility Testing-March 1998 <br /> On March 19 and 20, 1998, feasibility testing was conducted to evaluate the effectiveness of vapor extraction <br /> in remediatito hydrocarbon-ImpKted sods at the subject site, Tests Were condtictod at eight separate wells <br /> (W-1 through W-8) for a duration of 1 to 4 hours each using an internal combustion engine Due to low <br /> oxygen in subsurface, the internal combustion engine was unable to produce a vacuum exceeding 4 inches <br /> of water at any well, therefore, Induced vacuum could nqt be measured at any of the surrounding wells <br /> Based on flow rates obtained during testing and their undeFstanding of site conditions, SECOR estirrtates the <br /> actual radius-of-influence at each well to be approximately 50 feet <br /> A summary of pilot test data follows <br /> W01Screened Interval Max Applied Vacuum R ullUag Air Flow TPH-a Concentration Initial Mass Removal Rate <br /> W-1 10 -40 feet 2 in water 12 5 cfm 70$ppmv 3 6 lbs/day <br /> W-2 5 -45 feet 2 in water 12,5 din 7 240 ppmv 6 5 Ibs/day <br /> W-3 5-40 feet 2 5 in water 19 9 cfrn 179,000 ppmv 1 425 lbs/day <br /> W-4 5-30 feet 3 5,n water 14 2 cfrn 3 130 ppmv 17 1 Ibs/day <br /> W-5 10-30 feet 3 m water 26 9 cfm 221 ppmv 2A lbs/day <br /> W-6 10-30 feet 3 in water 19 9 din 139 ppmv 1 1 lbs/day <br /> " W-7 25-56 feet 2 in water 19 6 cfm 2,670 ppmv 20 9 lbs/day <br /> r W-8 25-56 feet 2 in water 20 7 cfrn 23,000 ppmv 175 ibe/day <br />