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Problem Assessment Report Page I i
<br /> Ranch Market,23569 South Santa Fe Road Riverbank,CA November 8,2000
<br /> During Test#2 induced vacuum readings greater than 0 2 in H2O were reported in wells V-2,
<br /> V-3, V-4, V-5, and V-6, which are located 20 to 38 feet away from extraction well V-1
<br /> During Test#3 induced vacuum readings greater than 0 2 in H2O were reported in wells V-1,
<br /> V-2, V-3, and V-4, which are located 20 to 36 feet away from extraction well V-5 Well V-6,
<br /> located 19 feet away from the extraction well had induced vacuums less than 0 16 in H2O
<br /> 7.2.2 Vapor Extraction Results for Test #4
<br />' Prior to conducting the six well SVE test on October 3, 2000, the static depth to water and
<br /> dissolved oxygen concentration was monitored in wells MW-1, MW-2, MW-3, MW-4, the six
<br /> SVE wells, and AS-1 (Table 5) Depth to water and dissolved oxygen readings were also
<br />' collected prior to termination of the six well SVE test, at the start of the AS test, during the
<br /> AS test, and immediately before termination of the test
<br />' During the six well SVE test, which operated for approximately 3 hours, the combined well
<br /> field produced flow rates that ranged from 165 to 220 scfm with applied vacuums of 20 to 30
<br />' in H2O (Table 6) Since the maximum flow rate of the vapor treatment unit is 250 scfm, the
<br /> maximum applied vacuum was limited to 30 in H2O Individual well extraction rates ranged
<br /> from 20 to 30 scfm The FID readings collected from the vapor extracted from combined well
<br />' flow started at 10,000 ppm and declined to 5,000 ppm after three hours of extraction
<br /> During Test#4 induced vacuum readings greater than 0 2 in H2O were reported in wells
<br />'. MW-1, MW-2, MW-3, and MW-4 No significant increase in dissolved oxygen was observed
<br /> and the groundwater raised less that 1 inch in the offsetting groundwater monitoring wells
<br /> (Table 5)
<br />' 7.2.3 Vapor Extraction/Air Sparge Results for Test #5
<br /> Prior to conducting the combined SVE/AS test on October 3, 2000, the static depth to water
<br /> t and dissolved oxygen concentration was monitored in wells MW-1, MW-2, MW-3, MW-4,
<br /> the six SVE wells, and AS-1 (Table 5) Depth to water and dissolved oxygen readings were
<br /> also collected, at the start of the AS test, during the AS test, and immediately before
<br />' termination of the test
<br /> During the 3-hour SVEIAS test, air was infected into AS-1 at 6 scfm with infection pressures
<br />' ranging from 6 to 9 psi (Table 6) Concurrent with the air infection, vapor was extracted from
<br /> the six wells at rates ranging from 153 to 170 scfm with an applied vacuum of 25 in H2O
<br /> (Table 6) The influent vapor FID readings collected prior to air sparging were 5,000 ppm
<br />' After startup of the air sparging, the influent vapor concentrations declined to 2,500 ppm, rose
<br /> to 3,700 ppm after 2 hours, and declined to 1,600 by the end of the test
<br /> tDuring the air sparge test the dissolved oxygen concentrations increased in well MW-1,
<br /> located approximately 8 feet away from AS-1, from 0 5 ppm to 11 8 ppm (Table 5) No
<br /> significant increase in dissolved oxygen was observed in well MW-2, MW-3, and MW-4 that
<br />' are Iocated from 34 to 48 feet away from AS-1 During the SVE/AS test, induced pressure
<br /> was observed in MW-1, MW-2, and MW-4, but not in MW-3 (Table 6) The groundwater
<br /> level raised less that 1 inch in the offsetting groundwater monitoring wells (Table 5)
<br />' SECOR International Incorporated
<br /> File PAR-report doc rp
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