|
Lower Water Bearing Zone (Sand Zone 2)
<br /> During the site visits conducted on April 19 and 26, 2004, free product was measured in well MWA at
<br /> thicknesses ranging from 0 01 to 0 02 feet A sheen was observed in well MWA on the May 24, 2004 site
<br /> visit In the site visits where free product was measured in well MW-1, free product was manually bailed
<br /> from well MWA and placed in properly labeled DOT approved drums pending disposal Approximately 5
<br /> gallons of a productlwater mixture was bailed from well MWA during the second quarter 2004
<br /> Approximately 190 gallons of productlwater mixture have been bailed to date Product thickness
<br /> measurements and volumes of liquid bailed are summarized in Table 1
<br /> At the time of the second quarter 2004 monitoring event, the groundwater level in well MWA had
<br /> increased 0 16 feet since the previous monitoring event (March 15, 2004) Depth-to-water measurements
<br /> were normalized to mean sea level (MSL) and used to construct a groundwater elevation contour map
<br /> (Figure 4) Wells that contained less than 1 foot of water are interpreted to be dry and are indicated as
<br /> "dry" on Figure 4 Groundwater flow was to the east at a gradient of 0 035 fttft Data regarding the
<br /> historical groundwater flow in the deeper water bearing zone is not available
<br /> GRO and benzene were reported in wells MW-1, MW-10, MW-12, and MW-15 The highest
<br /> concentrations of GRO (110,000 µg/L) were found in both wells MW-1 and MW-15 The highest
<br /> concentration of benzene (28,000 lig/L) was reported in well MW-1 1,2-DCA(1,300 jig/L)was reported in
<br /> well MW-1 MTBE, TBA, DIPE, ETBE, EDB, or ethanol were not reported in any of the lower zone wells
<br /> Analytical results for the second quarter 2004 are generally consistent with previous quarters GRO,
<br /> benzene, and MTBE analytical data for the samples collected on June 21, 2004, are presented in
<br /> Figure 5 Analytical data were submitted to the State Water Resources Control Board as required by
<br /> AB2886 The electronic delivery receipt is attached in Appendix C
<br /> . SVE System Operation and Maintenance
<br /> Stratus conducted eleven site visits during the second quarter 2004 to conduct operation and
<br /> maintenance of the SVE system, and to collect compliance samples The systems identified as SVE unit
<br /> 1 (SL No 9321) and SVE unit 2 (SL No 9230) were started for continuous operation beginning March
<br /> 15, 2004 SVE unit 1 was shutdown on May 17, 2004, to replace a solid state relay The system was
<br /> re-started on May 17, 2004, and has been operating at 100% uptime since then SVE unit 2 was observed
<br /> non-operational during the site visits conducted on April 12, April 19, April 26, May 3, May 10, and May 17,
<br /> 2004, due to high temperature alarm The SVE unit 2 was re-started on the same day it was observed
<br /> non-operational by adjusting the temperature controls On May 19, 2004, the high tempertature shut-off
<br /> switch was replaced on SVE unit 2 and the system has been operating at 100% uptime (as of June 29,
<br /> 2004)
<br /> During the second quarter 2004, the influent GRO concentrations to SVE unit 1 and SVE unit 2 fluctuated
<br /> in the ranges of 2,600 to 15,000 milligrams per cubic meter (mglm3) and 1,000 to 5,700 mglm3,
<br /> respectively The average soil vapor extraction flow rates for SVE unit 1 and SVE unit 2 were observed at
<br /> 123 91 cubic feet per minute (cfm) at an average applied vacuum of 12 inches of water column, and
<br /> 157 12 cfm at an average applied vacuum of 11 82 inches of water column During the second quarter
<br /> 2004, approximately 2,725 pounds and 1,076 of GRO was extracted and abated by the SVE unit 1 and
<br /> SVE unit 2, respectively Influent GRO and cumulative GRO mass removed from both SVE units 1 and 2
<br /> are presented in Figures 6 and 7 Since the system start-up a cumulative mass of 3,801 pounds of GRO
<br /> has been removed from the subsurface beneath the site by both the units The destruction efficiency of
<br /> both the SVE systems for GRO was observed to at or greater than 95% The SVE system is operating as
<br /> designed and is in compliance with the SJVAPCD permit requirements
<br /> P\Bp-Arco for URS\6100%Quarterly\2004\Arco_6100_2Q04 doc STRATUS
<br />
|