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<br />L.ntvron rrwucts tympany ea e 2
<br />Former Chevron Service Station #9-5775, 301 West Kettleman Lane, Lodi, California January 11, 2002
<br />3.0 EVALUATION OF GROUNDWATER EXTRACTION AND SOIL VAPOR
<br />EXTRACTION SYSTEMS
<br />GWE and SVE systems were initiated on July 3, 2000. Certified analytical reports and
<br />chain -of -custody documentation and remedial system operation and maintenance field data
<br />sheets are included in Attachments E and F, respectively. A brief description and
<br />performance evaluation of the remedial system during the 40' quarter 2001 are presented
<br />below.
<br />3.1 Groundwater Extraction System
<br />The groundwater extraction system consists of groundwater extraction wells EX -1, EX -2 and
<br />EX -3 (Figure 5). These wells are equipped with submersible pumps connected through
<br />mechanical piping to a series of granular activated carbon (GAC) vessels prior to an
<br />industrial sewer discharge point. Chevron discharges treated groundwater at the subject site
<br />under City of Lodi Wastewater Discharge Permit #295. Pumping through the wells from
<br />areas affected by petroleum hydrocarbons prevents migration of these hydrocarbons off-site.
<br />To assess effectiveness of the GWE system, process samples were collected weekly during
<br />this reporting period. Sample locations include an influent port (INFL), prior to the first
<br />GAC vessel, between the first and second GAC vessels (MID -1), between the second and
<br />third GAC vessels (MID -2), and prior to discharge (EFFL) to the industrial sewer. During
<br />these sampling events, influent (INFL), midpoint 1 (MID -1), midpoint 2 (MID -2), and
<br />effluent (EFFL) samples were analyzed for TPHg, benzene, BTEX compounds, MtBE, TBA,
<br />DIPE, EtBE, TAME, ethanol, methanol, EDB, and 1,2 -DCA. Maximum concentrations of
<br />detected constituents are presented below. Current and historical analytical information is
<br />I:1Chevron1957751Periodic Monitoring\Quarterly Progress Reports%khQuarter 200114th Quarter -2001 Progress Report.doc
<br />Maximum Constituent Concentr`atioins .(µg11)
<br />Novetnber`I9 'through 20;'2001
<br />Zone
<br />TPHg
<br />Benzene
<br />Toluene
<br />Ethyl-; '
<br />Xylenes
<br />MtBE
<br />TBA
<br />EtBE
<br />TAME
<br />benzene
<br />A -zone
<br />1,300
<br />0.94
<br />0.92
<br />3.0
<br />1.9
<br />13,000
<br />390
<br />390
<br />130
<br />B -zone
<br /><50
<br />13
<br />0.92
<br /><0.5
<br /><1.5
<br /><0.5
<br /><5.0
<br />2.0
<br /><0.5
<br />Ozone
<br /><50
<br /><0.50
<br /><0.50
<br /><0.50
<br /><1.5
<br /><0.5
<br /><5.0
<br /><0.5
<br /><0.5
<br />Exolanations
<br />gg/1= Micrograms per liter
<br />< Indicates the constituent was not present at or above the method reporting limit shown
<br />3.0 EVALUATION OF GROUNDWATER EXTRACTION AND SOIL VAPOR
<br />EXTRACTION SYSTEMS
<br />GWE and SVE systems were initiated on July 3, 2000. Certified analytical reports and
<br />chain -of -custody documentation and remedial system operation and maintenance field data
<br />sheets are included in Attachments E and F, respectively. A brief description and
<br />performance evaluation of the remedial system during the 40' quarter 2001 are presented
<br />below.
<br />3.1 Groundwater Extraction System
<br />The groundwater extraction system consists of groundwater extraction wells EX -1, EX -2 and
<br />EX -3 (Figure 5). These wells are equipped with submersible pumps connected through
<br />mechanical piping to a series of granular activated carbon (GAC) vessels prior to an
<br />industrial sewer discharge point. Chevron discharges treated groundwater at the subject site
<br />under City of Lodi Wastewater Discharge Permit #295. Pumping through the wells from
<br />areas affected by petroleum hydrocarbons prevents migration of these hydrocarbons off-site.
<br />To assess effectiveness of the GWE system, process samples were collected weekly during
<br />this reporting period. Sample locations include an influent port (INFL), prior to the first
<br />GAC vessel, between the first and second GAC vessels (MID -1), between the second and
<br />third GAC vessels (MID -2), and prior to discharge (EFFL) to the industrial sewer. During
<br />these sampling events, influent (INFL), midpoint 1 (MID -1), midpoint 2 (MID -2), and
<br />effluent (EFFL) samples were analyzed for TPHg, benzene, BTEX compounds, MtBE, TBA,
<br />DIPE, EtBE, TAME, ethanol, methanol, EDB, and 1,2 -DCA. Maximum concentrations of
<br />detected constituents are presented below. Current and historical analytical information is
<br />I:1Chevron1957751Periodic Monitoring\Quarterly Progress Reports%khQuarter 200114th Quarter -2001 Progress Report.doc
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