Tuesday, November 6, 2007 : 2:40 p.m.
Field and Laboratory Evidence for Reaching a Practical LNAPL Recovery Endpoint: A Case Study for Fuel Oil in Alluvium
Demonstration that a mobile light non-aqueous phase liquid (LNAPL) plume has been recovered to the degree practicable should be based on scientific principles supported by field and laboratory evidence accounting for site conditions that influence LNAPL mobility. The controlling factors generally include fluid and matrix properties, the spatial distribution of LNAPL mass, and fluctuations in the water table from climatic variations and remedial actions. We present a case study for reaching a practical hydraulic endpoint after remediation of a sudden release of fuel oil into river alluvium. The timing and volume of the release were precisely known, and occurred on a site that had been previously investigated. This helped the owner-operator and other responders implement aggressive emergency remedial actions that contained and recovered approximately 58% of the release volume within 60 days of its discovery. After another 15 months of declining LNAPL recovery rates and thinning of observable oil in wells, a field study was conducted to collect and analyze the fluid and soil matrix properties from soil cores in the smear zone, along with baildown tests at a well with the most remaining LNAPL (< 0.3 feet). Using the historical fluid level data to map the smear zone and laboratory core analyses for native-state and residual oil saturations, a mass balance with < 5% error was achieved on LNAPL mass remaining in the subsurface at near-residual saturations. Quantitative estimates of oil conductivity and transmissivity were made for the thin oil accumulations in a few wells to support the position that a practical limit on recovery had been reached at this site. Monitoring of fluid levels in nearby wells will be used to confirm the expected plume stability after the recovery system is shut down.
Don A. Lundy, PG, Environmental Systems & Technologies Don Lundy is a Principal Hydrogeologist with 28 years of professional experience after earning an MS in Geology with a groundwater/geochemistry theis from the University of Wyoming. Since the early 1980's, his specialization has been in the characterization and remediation of LNAPL and DNAPL plumes. In the past 7 years, he has organized and helped present five short courses on developing LNAPL conceptual site models for quantitative assessments of LNAPL plume stability, mobility, and recoverability.
David R. Bennett, Environmental Systems & Tech David Bennett is a Senior Project Scientist with ES&T and has 15 years of experience developing site conceptual models, applying numerical models to environmental sites, designing computer animations and graphics, and administering computer networks. His experience includes field applications of computer models, database management, regulatory interaction, corrective measures studies and risk assessment. David developed multiphase models for LNAPL and groundwater flow and dissolved-phase transport at a variety of large-scale industrial sites, including oil refineries, providing regulatory and litigation support. He earned his BS in Geology from Virginia Tech He is a member of NGWA and the International Groundwater Modeling Center.
Michael Maegerle, GES Michael Maegerle is a Senior Geologist/Senior Site Manager with Groundwater & Environmental Services, Inc. (GES) and has been in the environmental consulting industry since 1995. Prior to working for GES, he worked for the New Jersey Department of Environmental Protection (NJDEP) regulating the assessment and cleanup of contaminated sites in Spill, Superfund, RCRA, ISRA and UST Programs. He has a B.S. in Geophysics from the University of Delaware and an M.S. in GeoEnvironmental Studies from Shippensburg University.
Ray Leather, Warren Equities Inc. Leather is Director of Environmental Affairs for Warren Equities, Inc., a distributor of petroleum products for 600 stations in 10 states. He has worked in the petroleum assessment and remediation field since 1974 and is a member of API and state regulatory committees. He has a B.S. in Civil Engineering from Merrimack College, an M.S. in Energy Management & Power from the University of Pennsylvania; and, an M.B.A. from University of Houston. He is a Registered Petroleum Operations Engineer, Registered Professional Engineer, Licensed Site Professional in the Commonwealth of Massachusetts, and Registered Environmental Assessor I in California.
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