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Bioremediation Report - 4 - 3 October 1994 16 S. Cherokee Lane, Lodi Calculations - They calculated the hydraulic conductivity, permeability, and velocity. • All assumptions and calculations were provided. Based on these calculations and their conclusions from the soil boring drilled during the Pilot Study, GeoAudit claims that "the bacteria migrated in the soil at least 5 feet in 60 days. This calculates to a migration rate of at least 30 feet per year. Using this conservative estimate, if bacteria are inoculated into the proposed wells..., groundwater at the site should show significant improvement within 3 months and should be remediated within one year." Comment - P2 was drilled 5 feet from an inoculation point 60 days after inoculation. Contamination levels in P2 showed no indication of having been remediated. This does not support the statement that the bacteria moved 5 feet in 60 days. They may be basing this claim on biological data not available to us, but they may have overestimated the distance the bacteria will move. Blower System - Currently the low pressure blower system injects oxygen (as air) into the tops of wells VW1, VW7, MW3, MW4, MWS, and MW14. A sampling port was installed in each well cap. GeoAudit proposes to inject air into the bottom of the wells through small diameter PVC piping in order to obtain more accurate measurements of oxygen and carbon dioxide. At present, only MW14 contains ground water. In MW14, the air will be injected beneath the ground water (sparging). The PVC piping in MW14 will be removable for ground water sample collection. Comment - Injection of air into the bottom of the wells may provide more oxygen where • needed. Comment - No mention was made of what will happen to the air injection system and ground water sample collection capability in the currently dry wells if the ground water level increases. Comment - No mention was made about wells VW2 through VW6, which are also hooked up to the air injection system. C. GeoAudit's Proposed Bioremediation Sampling Plan Vapor Sampling - Oxygen, carbon dioxide, and organic vapor samples will be collected weekly throughout the remediation project. The samples will be collected from the bottom of the wells via plastic tubing. Oxygen and carbon dioxide samples will be analyzed using field meters. Organic vapor samples will be analyzed with a PID. The air blower will be turned off 24 hours prior to vapor sample collection. This should allow time for vapor levels to stabilize and provide more accurate samples. The effectiveness of the blower system will be analyzed quarterly. Options that may improve air flow, including pulsing of oxygen, additional sparge wells, and air flow reversal, may be implemented at a later date. Comment - Both injection of air and collection of samples from the bottoms of the wells may • continue to create a problem in collection of good oxygen and carbon dioxide samples. However, the 24-hour down time prior to sample collection may help.