5 Wing Goose Bay Remediation Project...LNAPL Management Framework 5 Wing Goose Bay: Case Study 5...
Transcript of 5 Wing Goose Bay Remediation Project...LNAPL Management Framework 5 Wing Goose Bay: Case Study 5...
LNAPL Management Framework 5 Wing Goose Bay: Case Study 5 Wing Goose Bay Remediation Project Tom MacNeil, P. Eng., AMEC Environment & Infrastructure
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Background – History
§ History of 5 Wing Goose Bay § 5 Wing Goose Bay was
founded in 1941 - still active § Re-fuelling trans-Atlantic
flights § 6 tank farms – 2 active § 50 plus ASTs with capacity in
excess of 300 M litres § Dozens of former USTs § 160 km of pipelines
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Site of Interest – Heavy Bomber Hydrant Area
§ Land Use – airport apron, green space § Water table – 15+ m below ground surface § Unconfined sand aquifer § Apparent LNAPL Thickness up to 3 m, Jet Fuel § LNAPL present currently as 2 discrete plumes § History of spills unknown but occurred decades ago § Active remediation ongoing since fall 2012 – 3 MPVE systems, 75
recovery wells
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Site of Interest – Heavy Bomber Hydrant Area
§ )
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LNAPL Management Framework
§ Phase 1 – Identify goals § Phase 2 – Data collection § Phase 3 – Data analysis § Phase 4 – Implementation § Phase 5 – Reporting & closure
§ Iterative process
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LNAPL Management Framework – Identify Goals (Phase 1)
§ GBRP Objective § “to remediate or risk manage legacy impacts in a way that
appropriately reduces the risk to human and/or environmental health to acceptable levels”
§ Actual / potential pathways § Direct – none (LNAPL at depth, no potable water usage) § Indirect – maybe (LNAPL or dissolved plume stability)
§ Is action necessary? § Yes
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LNAPL Management Framework – Data Collection (Phase 2)
§ Data Collection § Soil/Groundwater Investigations – 75+ MW’s § LNAPL Gauging – 3 years; quarterly to date § Dissolved Phase Monitoring - 3 quarters at 55+ locations § LNAPL Mobility Assessment § Groundwater Flow and Transport Modeling (basewide) § 2 LIF Investigations § 1 MIP Investigation
§ Identify data gaps – above investigations taken place over past 8 years
§ Data has been assembled into LCSM
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LNAPL Management Framework – Data Collection (Phase 2)
§ Lines of Evidence § LNAPL Mobility/Recoverability § LNAPL Transmissivity § LNAPL Plume Stability § Dissolved Plume Stability § Monitored Natural Attenuation Capacity
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LNAPL Management Framework – Data Analysis / Lines of Evidence (Phase 3)
§ LNAPL Mobility/Recoverability – MPVE recovery in decline, still variable with water table elevation
§ LNAPL Transmissivity – individual wells are above and below de minimus threshold for mobility
§ LNAPL Plume Stability – plume footprint appears stable § Dissolved Plume Stability – plume appears stable, limited data
at this point § Natural Attenuation – documented to be occurring on the site
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LNAPL Management Framework – Implementation (Phase 4)
§ Implementation § Operate 3 MPVE Systems through 2 more seasonal GW lows § Data Collection
– MPVE system recovery – LNAPL Monitoring – Stable?? – Dissolved Phase – Stable?? – LIF Investigations – LNAPL Transmissivity – meets de minimus criteria?? – MNA – document site capabilities – Minimum of 8 quarters following system shutdown
§ Long Term Monitoring § Less intensive than Closure Monitoring § Confirm closure conditions are maintained
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LNAPL Management Framework – Reporting & Closure (Phase 5)
§ Update LCSM § Net Benefits – Key Considerations
§ Impossible to recover all LNAPL § Removal of all recoverable LNAPL predicted to take up to 9
additional years of MPVE system operation § No “walk away solution” § Energy use of remedy § Transfer of contaminant from one media to another § What is cost of recovery?
§ Reduce risk to acceptable level – Goal of GBRP § Can only remediate to current or intended federal use
§ Closure – present all material relevant material in overall site context
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Conclusion
Questions???