|
Tosco Corporation,a subsidiary of Phillips Petroleum Company 2
<br /> Tosco Station#1205,16470 Cambndge street,Lathrop,CA June 26,2002
<br /> The total DPE time was approximately 95 hours Groundwater and soil vapor were
<br /> 10 removed simultaneously from the respective test wells by applying a high vacuum to a
<br /> drop pipe that was lowered into the water table within each test well
<br /> Physical and chemical parameters including applied vacuum, groundwater and soil vapor
<br /> extraction flow rates, soil vapor temperature, and hydrocarbon vapor concentration
<br /> measurements were monitored throughout the DPE event Vapor concentrations were
<br /> measured using a flame ionization detector(FID) Vacuum gauges were placed at nearby
<br /> monitor wells in order to monitor the negative pressure gradient induced by DPE at the
<br /> respective extraction well DPE test data is summarized in Table 1 Field data sheets are
<br /> included in Attachment B
<br /> Using Tedlar bags, SECOR collected air samples from the DPE system influent vapor
<br /> stream and from the DPE effluent vapor stream Effluent samples were collected and
<br /> analyzed Influent samples were collected near the beginning of each test Groundwater
<br /> samples were collected from monitoring wells MW-1, MW-2, MW-5, MW-6, and MW-7
<br /> on the first day of the test,March 25, 2002 and on the last day of the test, March 29,
<br /> 2002 Knockout tank samples (KO) were collected five times throughout the test Air
<br /> and water samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg),
<br /> benzene, toluene, ethylbenzene, xylenes (BTEX compounds), and methyl tert-butyl ether
<br /> (MtBE) by Department of Health Services, Leaking Underground Fuel Tank Method
<br /> (DHS LUFT) Groundwater samples, one knockout tank sample (KO#3), and one air
<br /> • sample (INF#1) were also analyzed for methyl-tert butyl ether(MtBE), tert butyl alcohol
<br /> (TBA), di-isopropyl ether(RIPE), ethyl tert-butyl ether(ETBE), tert-amyl methyl ether
<br /> (TAME), ethylene dibromide (EDB), and ethanol using EPA Method 8260 Lead by
<br /> EPA Method 6010B was requested for INF#1, however, the lab could not run the
<br /> analysis on the air sample Results of these analyses are presented in Tables 2 and 3
<br /> Certified laboratory analytical reports and chain-of-custody documentation data are
<br /> presented in Attachment B
<br /> DPE RESULTS
<br /> During the 4-hour DPE event for well MW-5, the applied vacuum averaged 25 inches of
<br /> mercury(in of Hg), vapor extraction flow rates ranged from 28 34 cubic feet per minute
<br /> (cfm) to 30 52 cfm Groundwater elevations for observation wells MW-1, MW-2, MW-
<br /> 6, and MW-7 decreased by 0 09 feet, 0 06 feet, 0 07 feet, and 0 01 feet, respectively,
<br /> while well MW-4 did not show any significant changes in groundwater elevations The
<br /> groundwater extraction flow rate ranged from 10 gallon per minute (gpm) to 3 0 gpm
<br /> FID readings collected from the vapor extracted were greater than 10,000 parts per
<br /> million by volume (ppmv)throughout the test Applied vacuum, vapor extraction flow
<br /> rates, groundwater extraction flow rates, and influent FID readings are presented in
<br /> Table 1
<br /> During the 3 i/2-hour DPE event for well MW-6, the applied vacuum ranged from 20 in
<br /> • of Hg to 23 in of Hg, vapor extraction flow rates ranged from 23 98 cfm to 48 17 cfm
<br /> Groundwater elevations for wells MW-5, MW-1, MW-2, and MW-7 decreased by 0 15
<br /> feet, 0 07 feet, 0 06 feet, and 0 03 feet, respectively, while well MW-4 did not show any
<br />
|