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ATC Associates,Inc Project No 99975 7501 4.0 REMEDIATION STATUS AND EFFECTIVENESS REPORT Soil vapor extraction(SVE)and groundwater extraction at the site began on February 10, 1994 Since that time,through November 30, 1998,more than 3 5 million gallons of groundwater and 22 million cubic feet of soil vapor have been extracted from four soil vapor and groundwater co- extraction wells at the site. Prior to discharge to the atmosphere and surface,the soil vapor and groundwater are treated through 2,000-pound vapor phase and aqueous phase carbon units, respectively A log of groundwater production is presented in Table 4 and the groundwater influent and effluent analyses are presented in Table 5 Table 6 is a log of the production and analysis of extracted soil vapor, and Table 7 is a corresponding log for the treated effluent 1 The data which are most significant for assessing the progress of the remediation program are the groundwater monitoring results presented in Table 2 These results show total elimination ' of total hydrocarbons in most of the previously impacted monitoring wells, and reductions of 80-90 percent in the severely impacted monitoring wells BEI-MW3 and BEI-MW 1 Reductions of benzene in these wells are more than 85 percent and 96 percent, respectively The most significant observation,regarding the remediation process is the considerable amount g g g of bio-mass evident in the groundwater immediately after its extraction This was particularly apparent during the initial months after the remediation program was initiated This occurrence provides evidence that the physical and chemical characteristics for bio-degradation in the groundwater both above and below the surface,are particularly favorable ATC believes the migration of fresh oxygenated air and water through the site as a result of the soil vapor and groundwater extraction has effected the removal of far greater amounts of hydrocarbons,by the ' process of enhanced bio-degradation, than have been recovered above ground in the respective SVE and groundwater carbon treatment units A more comprehensive discussion of remediation effectiveness will be discussed in the next report, to be submitted in January 1999, which will present the results of the December monitoring and the results of vacuum testing at the site which will provide additional data for ' assessing the radius of(soil vapor extraction) influence around the co-extraction wells ' 5.0 SELF-MONITORING PROGRAM SCHEDULE The next quarterly groundwater monitoring event is scheduled for December 1998 Groundwater Monitoring and Remediation Status Report Page 3 1