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Fourth Quarter 1993 Status Report January 6, 1994 . Golden Grain Company, Manteca Bean Facility, 229 Moffat Blvd , Manteca CA 5 During this quarter, the air stripper was dismantled and cleaned on October 22 and November 17, 1993, for routine maintenance There was no discharge of system water during these maintenance events (see page 4, Treatment System Summary) A total of 117,927 gallons of water were treated between September 3 and December 1, 1993 VAPOR EXTRACTION MONITORING On November 11 and 17, 1993, vapor extraction monitoring was conducted to evaluate the subsurface effects of the vapor extraction system (VES) and quantify the static vapor concentrations of TPH-G in the sods located within the VES treatment area On November 11, 1993, air samples were collected for analysis from the VES influent, the effluent of the lead scrubber, and the effluent of the catalytic scavenger unit The samples were analyzed for BTEX, TPH-G, total lead, and organic lead Results of laboratory analyses are shown in Table 5 Laboratory results indicate that effluent concentrations for all compounds or analytes that were analyzed for were below detection limits These effluent analysis results are below the 100 ppmv TPH-G limits set by the Unified Air Pollution Control District's permit to operate Before the vapor extraction system was sampled, the applied vacuum was measured at the two . vapor extraction wells and the induced vacuum was measured at the monitoring wells within the VES treatment area (Tables 7 and 8) Readings were taken using a magnahelic gauge measured in inches of water vacuum Readings were gathered to determine extraction well efficiency and the influence of the vapor extraction wells on the surrounding sod Results of field data collected this quarter indicate the expected vacuum effect on the surrounding area The Vapor Extraction Pilot study performed in 1990 determined a radius of influence ranging from 55 feet to 90 feet depending on the air flow rate being pulled from the test extraction well The readings collected on November 11, 1993, showed influence 70 feet away from well MW-2 at a flow rate of approximately 60 cubic feet per minute (cfm) This corresponds with the expected radius of influence determined from the pilot study Before collecting the VES ambient subsurface vapor concentration data, the normal vacuum applied to the vapor extraction wells was turned off for a period of 5 days This allowed the subsurface to reach static conditions before the collection of the vapor samples from the vapor extraction wells and MW-1, MW-4, MW-5, and MW-6 On November 17, 1993, vapor samples were collected from these wells and subsequently analyzed for TPH-G and BTEX (results in Table 6) 38nR023 070 i GROUNDWATER HD TECHNOLOGY,INC