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R604 UPDATE 14 12-28-1992 Plate on the vapor recovery manifold The tubing is then connected to a tedlar bag placed inside a vacuum sampler The sample port is then opened and the vacuum placed on the tedlar bag from the sample vessel allows the tedlar bag to fill with the vapor stream from that particular sample port . Once the tedlar bag is full the valve is closed and the vacuum removed from the sample vessel The tedlar bag contains an air tight locking septum valve which is then closed and locked to secure the vapor sample . A small dedicated needle attached to a dedicated 1 cc syringe is then inserted through the sample septum into the tedlar bag The 1cc syringe is purged numerous times before filling it with the sample All but 0 5 cc of the sample is effected into the air before injecting the remaining 0 5 cc syringe sample into the Schimadzau FID-GC (the calibrant injection is 0 5 cc) Once the chromatogram is recorded, an instrument blank is run prior to the next sample The instrument blank will indicate if residual peaks are being carried onto the next analysis Vacuum influent readings are obtained from the wells by attaching a manometer calibrated in mm water to sample ports at the well heads . These readings show the mm water pressure or vacuum that is being created at each well Vapor Recovery Results The vapor extraction system was shut down on November 21, 1991 on completion of operation under Initial Variance ##91-19 and 90 day Variance #91-20 . A total of 13 , 116 pounds of gasoline range hydrocarbons was removed from the soils and ground water beneath this site by that time, see Figure 7 The vadose zone vapor recovery wells (P1, P3-Swarm and EX) contributed little to the total recovered hydrocarbons during this time period, P1 = 1 3 pounds, P3-Swarm = 561 4 pounds and EX 127 pounds The system was restarted under the Authority to Construct Permit (AP 91-106) on March 31, 1992 On July 21, 22 , and 23 , 1992 , four new vadose zone vapor recovery wells were installed and manifolded to the recovery system As of November 17, 1992 the new wells along with MW5 have produced 1695 4 pounds of gasoline range hydrocarbons, for a total recovery of 15 , 603 72 pounds From November 17 to December 9, 1992 only 235 pounds of gasoline range hydrocarbons have been removed via vapor extraction at this site for a total recovery of 15 , 839 11 pounds, see Table 3 and Figure 7 Vacuum Influence: Soil contamination has been documented as being associated with the pump dispensers and the tank field as degraded gasoline range page 6