fmc spill site july 11, 1996: tanker truck turned over spilling 6000 gallons (23000l) gasoline 500ft...
TRANSCRIPT
FMC SPILL SITE
• July 11, 1996: Tanker truck turned over spilling 6000 gallons (23000L) gasoline
• 500ft (150m) North from Bear Creek
• Emergency Response Team observed no standing gasoline, rapid infiltration
• The ERT was unable to locate subsurface free product
History
CLUBB, MISSOURI, USA
FMC SPILL SITEOverturned Tanker Truck
FMC SPILL SITE
• 10ft (3m) dry silty sand top layer, 10ft (3m) wet sandy clay with gravel underneath
• Porosity ~0.4
• Conductivity ~85ft/d (26m/d)
• Aquifer thickness ~20ft (6m)
• Groundwater surface ~7ft (2m) below ground surface
• Gradient estimated to be 0.0174 towards the southeast
Site Geology
FMC SPILL SITE
FMC SPILL SITETruck Location Spill Site
FMC SPILL SITE
• Contractor #1 (07/96)
– Geoprobed site to identify location of free product (07/96)
– Installed 4 monitoring wells
– Suggested air-sparging system (State did not approve)
– State noticed drillers were not licensed, equipment not registered (08/96)
Chronology of events (1996)
FMC SPILL SITE
FMC SPILL SITE
• FMC
– Geoprobed site, found 6” (15cm) free product along the north and south side of highway (08/96)
– Installed an interceptor trench south of the highway
– Recovered free product from trench (09/96)
Chronology of events (1996)
FMC SPILL SITEInterceptor Trench Construction
FMC SPILL SITEInterceptor Trench Construction
FMC SPILL SITEInterceptor Trench Construction
FMC SPILL SITE
• Contractor #2 (09/96)– Geoprobed site to locate free product and plume
(10/96)
– Free product plume about 400ft (120m) long and 100ft (30m) wide
– Pump test showed tranmissivities ranging 1100-2000 ft2/d (100-186 m2/d)
– Estimated conductivity was 85ft/d (26m/d)
• Interceptor trench showed 3" (8cm) free product (10/96)
Chronology of events (1996)
FMC SPILL SITE
• High levels of BTEX migrated to the stream
FMC SPILL SITE
• Contractor #2 (Cont.)
– Installed 5 remediation wells, depth around 24ft (7m) inside interceptor trench (11/96)
– Manual operation of free product recovery system started in January 1997
– Remediation system running 24h/d halfway March 1997
– Pumping rates ~18 GPM (68 L/min), creating drawdowns of ~15ft (4.5m)
Chronology of events (96/97)
FMC SPILL SITE
FMC SPILL SITE
FMC SPILL SITE
• Contractor #2 (Cont.)
– Never got more than 100 gallons (378 L) of free product from recovery system (07/97)
– Contractor terminated in 07/97
• Contractor #3 (07/97)
– Unable to continue with existing system, remediation 3 weeks down.
– 2 MWs showed 19” (48cm) free product
– Dual Phase extraction system operative (04/98)
Chronology of events (97/98)
FMC SPILL SITEOverall Pump & Treat System
FMC SPILL SITE
FMC SPILL SITE
FMC SPILL SITE
• Poor handling of NAPL issue– Overpumping causing high drawdowns created
smear zone– Needed more monitor wells downgradient– Expensive remediation (Cadillac) system but
poorly designed and missing target NAPL zone
• Soil strata poorly defined
• Initial response contractors inappropriate and too slow
Failed System
FMC SPILL SITEDual Phase Vacuum Extraction