Laserfiche WebLink
R604 :UPDATE 22 9-17-1993 <br /> California Water Quality Goals" have been met for over 11 months, <br /> see Table 1 . <br /> Fecal Coliform: <br /> From December, 1991 through February, 1992, monthly fecal <br /> coliform samples were collected from monitor wells MW3 , MW4, MW5 <br /> and MW6 . Samples were again collected in June, 1992, from <br /> monitoring wells MW3, MW4 and MW6 . During the September 11, 1992 <br /> sampling, MW3 and MW6 were dry, no fecal coliform samples were <br /> obtained. Table 2 shows the results of these samples . As of <br /> June, 1992 all these wells are below detection limits, <2 . 2 MPN, <br /> for fecal coliform. <br /> VAPOR EXTRACTION <br /> Vapor Recovery Results <br /> The vapor extraction system was shut down on November 21, 1991 on <br /> completion of operation under Initial Variance #91-19 and 90 day <br /> Variance #91-20 . A total of 13 , 116 pounds of gasoline range <br /> hydrocarbons were removed from the soils and ground water beneath <br /> this site by that time <br /> The vadose zone vapor recovery wells (P1, P3-Swarm and EX) <br /> contributed little to the total recovered hydrocarbons during <br /> this time period• P1 = 1 .3 pounds, P3-Swarm = 561 .4 pounds and <br /> EX = 127 pounds. <br /> The system was restarted under the Authority to Construct Permit <br /> (AP 91-106) on March 31, 1992 . <br /> On July 21, 22 , and 23 , 1992, four new vadose zone vapor recovery <br /> wells were installed and manifolded to the recovery system. As <br /> of July 22 , 1992 the existing vapor extraction system (MW5, P1, <br /> P3-Swarm and EX) had produced 13902 . 8 and the newly installed <br /> well VSB3 produced 3 6 pounds of gasoline range hydrocarbons . <br /> Since that time only the newly installed wells (VSB3 , VSB5, VSB9 <br /> and VSB11) and MW5 have been used for vapor extraction. As of <br /> the latest sampling (August 20, 1993) the new wells and MW5 have <br /> removed 3975 pounds of gasoline range hydrocarbons, for a total <br /> recovery of 17877 pounds, see Table 3 and Charts of vapor <br /> recovery <br /> Vacuum Influence. <br /> As was stated earlier, vapor recovery has removed the lighter <br /> fractions of gasoline range (through ethylbenzene) petroleum <br /> hydrocarbons from the soil and has greatly reduced the petroleum <br /> hydrocarbons dissolved in the ground water beneath this site . <br /> Figure 3 represents the vacuum influence generated from the vapor <br /> recovery system, as measured before obtaining depth to ground <br /> water measurements, on August 20, 1993 <br /> page 3 <br />