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<br />Chevron Products Company Page 2
<br />Former Chevron Service Station #9-5775, 301 West Kettleman Lane, Lodi, California October 31, 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 systems during the 3Q02 are presented 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. CEMC discharges treated groundwater at the subject site
<br />under City of Lodi Wastewater Discharge Permit #310. 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 biweekly 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, INFL, MID -1, MID -2, and EFFL samples were analyzed for TPHg,
<br />benzene, BTEX compounds, MtBE, TBA, DIPE, EtBE, TAME, ethanol, methanol, EDB, and
<br />1,2 -DCA. Maximum concentrations of detected constituents are presented below. Current
<br />and historical analytical information is presented as Table 3.
<br />I:1Chevron1957751Pcriodic MonitoringlQuarterly Progress Reports1200213rd Quarter -2002 Progress Report.doc
<br />Maximum Constituent Concentrations (RA)
<br />July 29 through 30, 2002
<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 />1,400
<br /><5.0
<br /><5.0
<br /><5.0
<br /><5.0
<br />15,000
<br />410
<br />560
<br />160
<br />B -zone
<br /><50
<br /><0.5
<br /><0.5
<br /><0.5
<br /><0.5
<br />0.8
<br /><5
<br /><0.5
<br /><0.5
<br />C -zone
<br /><50
<br /><0.5
<br /><0.5
<br /><0.5
<br /><0.5
<br /><0.5
<br /><5
<br /><0.5
<br /><0.5
<br />Explanations:
<br />µg/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 systems during the 3Q02 are presented 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. CEMC discharges treated groundwater at the subject site
<br />under City of Lodi Wastewater Discharge Permit #310. 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 biweekly 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, INFL, MID -1, MID -2, and EFFL samples were analyzed for TPHg,
<br />benzene, BTEX compounds, MtBE, TBA, DIPE, EtBE, TAME, ethanol, methanol, EDB, and
<br />1,2 -DCA. Maximum concentrations of detected constituents are presented below. Current
<br />and historical analytical information is presented as Table 3.
<br />I:1Chevron1957751Pcriodic MonitoringlQuarterly Progress Reports1200213rd Quarter -2002 Progress Report.doc
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