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