SITE INFORMATION AND CORRESPONDENCE FILE 1

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Lessons Learned Field tests indicate that the system does not currently have sufficient power to run all the wells in bioslurp mode. Although, the system is rated at 100 SCFM we are averaging 65 CFM overall. When allocated among nine wells, that amounts to 7.22 CFM per well. With the current slurp tube diameter of 25 mm (P), our tube velocity is calculated to be 1303 ft/min. Approximately 2000 ft/min tube velocity is required for good bioslurping. During the next phase of activity, the authors plan to reduce the slurp tubes to 19 mm (3/4") diameter thereby increasing the tube velocity to 2375 ft/min. An additional problem encountered was the build up of condensate in the air effluent line. A small valved bypass was installed to drain the air effluent pipe and redirect the water into the influent trunk line, to be processed by the system. . The telemetry unit and training have proven to be more effective than expected. The unit was programmed to call out to base personnel in the event of a fault condition. Base personnel have been prompt in responding to alarms and due to the training course were able to restart the unit and perform necessary corrections. The system operating in microslurrp mode was not supplying enough recovered water to provide . an adequate and constant amount of seal water to the liquid ring pump, therefore additional water had to be added to system. In the future a water line should be hard piped to the system. Conclusions Extremely high vapor levels still exist at the site and based on performance, they are expected for sometime. Once the vapor concentration is reduced, the authors plan to increase the bioslurping of groundwater and the thin layer of LNAPL that exists. Although the site was not and still is not fully characterized, the nature of the problem required the authors to initiate remediation immediately. In this case, the system design provided a very flexible capability that allowed for initiation of remediation tailored to the mix of phases encountered. For example, petroleum thickness was reported to be approximately 100 mm (4"), however, when the authors arrived onsite, maximum thickness was measured at approximately 9 mm(.36"). If the authors had designated any other method of LNAPL removal, it would not have been applicable to the conditions encountered onsite. The authors feel that the MPX also provides a solid base to expand the system. Once, the plume is fully defined, a set of remediation wells will be installed in a fashion that can address the entire plume. If the determination is made that more power is needed, the authors will replace the liquid ring pump with one that has increased capacity. Currently 200 and 300 SCFM models are available. Off-gas treatment will also be modified to accommodate the high vapor concentrations. 389