ETHANOL DERAILMENT SITES’ IMPACT ON GROUNDWATER

QUALITYPresentation for

Governors’ Coalition on Ethanol

February 28, 2007

Five Derailments With Large Ethanol Releases Have Occurred Since 2005

•July 27, 2005. 60,000 gallon release. Balaton, Minnesota•August 31, 2005. 28,000 gallon release. South Hutchinson, Kansas•June 17, 2006. 12,000 gallon release. Missoula, Montana•October 20, 2006. > 100,000 gallon release. New Brighton, Pennsylvania• November 22, 2006. 30,000 gallon release. Courtland, Minnesota

New Brighton, PA• 23 ethanol tank cars derailed

• Several tankers ended up in the Beaver River

• Nine derailed tankers burned for 2 days

• 150 nearby residents were evacuated

New Brighton, PA

• About 365,000 gallons were released• Much of the ethanol/fuel burned.• Water 500 yards downstream was initially

clear of gasoline contaminants as were downgradient PS intakes.

• Ethanol springs from park soils at various locations.

• Monitoring wells have been installed.

Courtland, Minnesota

• Pumped remaining ethanol from 7 derailed tank cars on 82 year-old track.

• Ethanol ponded in dry creek bed and was not removed.

• Cleanup dependent on natural attenuation – no excavation and no NAPL removal.

• Groundwater is 1.5 to 6 feet below surface.• Ethanol (0.15 to 2.6%) and BTEX (2 mg/L)

present in MW samples (at least 6 MWs).

Balaton, Minnesota• Release prompted an evacuation of nearby

residents.• Accident considered human error at track switch

control.• Release contained soybean oil and denatured

ethanol.• Spill threatened recreational Lake Balaton.• Pooled ethanol was pumped into an aerated sewage

lagoon.• MWs indicate that the 2.5-year old plume has

moved about 380 feet.

Missoula, MT

• Release on coarse-textured soils• Foamed the area to prevent ignition• Over-excavated the saturated soils to a depth of 17

ft. and installed SVE in one area with residual ethanol.

• No detections in MWs beneath release site or downgradient of release site.

• Site manager is ready to close site.

Tanker held 28,488 gallons of ethanolof which 28,000 gallons were released on 8/31/05.

South Hutchinson, Kansas

RESPONSE

• Strong ethanol fumes caused the evacuation of nearby homes, the Hutchinson Mental Health Facility and a middle school.

• Sand and foam were spread on the ethanol to prevent ignition.

• Haz-Mat Response Inc. personnel managed the cleanup.

CLEANUP

• The majority of the ethanol (~18 inches deep) was contained in a 0.5-mile long ditch adjacent to the track. Some ethanol drained into a pond and flowed beneath a trestle to a larger lake before earthen dams could be constructed.

• Sumps were dug along the ditch so that the ethanol could be collected and pumped into portable tanks. Approximately 20,000 gallons were recovered.

Observations on the Residue

• Approximately 8,000 gallons were not recovered.

• Ethanol was continuously volatilized from the soils as noted by a strong odor of ethanol during summer 2006.

• Soil cores from the site were characterized as smelling like sewage.

Vapor Pressure (mm Hg)

If vapor pressure > 100 mm HgVolatilization from free phase (NAPL)Vaporization of residual

product from dry soil

Law of Partial PressurePtotal = PMTBE + Pother constituents

PMTBE = XMTBE PoMTBE

Pi (mm Hg)

27–280.8–0.9

2.80.2

0.7–0.8

GasolineConstituent

MTBEBenzeneToluene

Ethylbenzene

Xylenes

11%1%

10%2%

10%(NSTC, OSTP Report, June 1997)Arulanantham et al., 1999

Iso-octane (49)

% by Volume

Ethanol (49 - 57)

28,000-gallon ethanol spill location H-1H-3

H-6H-4

H-5H-2

H-1C

H-1 H-2 H-3 H-4 H-5 H-6

12 ft

0.7%

5 ft

2.4%

5 ft

0.6%

5 ft

4.8%

5 ft

1.6%

5 ft

0.6%

8.5 ft

5.6%

9.5 ft

4.0%

8.5 ft

2%

9 ft

0.8%

10 ft

4.8%

9 ft

4.2%

Vadose zone methane concentrations

12

14

16

18

20

22

24

26

28

0.0 2.0 4.0 6.0 8.0

methane

ethylene

ethane

toluene

total xylenes

0 30 60 90 120

Ethanol conc. (ug L-1)

-12

-14

-16

-18

-20

-22

-24

-26

-28

Methane

Ethylene

Ethane

Toluene

Total Xylenes

Ethanol

0 2 4 6 8

Concentration (ug L-1)

Geoprobe site H-2D

ep

th (

ft)

12

14

16

18

20

22

24

26

28

30

0.0 2.0 4.0 6.0 8.0 10.0

methane

ethylene

ethane

toluene

total xylenes

0 2 4 6 8

Methane

Toluene

Total Xylenes

Ethanol

Ethylene

Ethane

10-12

-14

-16

-18

-20

De

pth

(ft)

-22

-24

-26

-28

-30

Concentration (ug L-1)

Geoprobe site H-5

0 200 600400 800

Ethanol Conc. (ug L-1)

Field Measurements

pHDO

ORPConductance

FeMn

Alkalinity

PHASE 2 RESULTS

• Collected unsaturated zone cores for the determination of hydraulic conductivity, microbial consortia (Mike Hyman), and flow and transport dynamics (Bill Rixey).

• Triangulated direction of groundwater flow.• Installed 10 MWs with KDHE support.• Completed two rounds of sampling and

analysis of monitoring wells.

0’

20’

30’

40’

10’

coarse sand and gravel

medium sand

clay

fine to medium sand

Screen Depths forMonitoring Wells

16-19’

23-26’

29-32’

3-4’, 1.3x10-8 cm/sec6-7’, 5x10-10 cm/sec8-9’ 1.7x10-9 cm/sec

10-12’, 1.2x10-2 cm/sec

12-14’, 1.5x10-2 cm/sec18-20’, 2.5x10-2 cm/sec

20-22’, 1.0x10-1 cm/sec28-30’, 1.9x10-1 cm/sec

0’

20’

30’

40’

10’

coarse sand and gravel

medium sand

clay

fine to medium sand

16-19’

23-26’

29-32’

3-4’, 1.3x10-8 cm/sec6-7’, 5x10-10 cm/sec8-9’ 1.7x10-9 cm/sec

20-22’, 1.0x10-1 cm/sec28-30’, 1.9x10-1 cm/sec

12-32’

10-12’, 1.2x10-2 cm/sec

12-14’, 1.5x10-2 cm/sec18-20’, 2.5x10-2 cm/sec

Groundwater Flow

Shallow Groundwater Properties

NW

•Average gradient: 0.005 ft/ft•Hc: 0.02 cm/sec•v: 0.5 ft/day•Direction: North-Northeast towards Arkansas River

S

E

Water Table

gasoline and/or ethanol

water

Groundwater

•Contaminant spreading in capillary fringe due to decreased surface and interfacial tension.

•Predominately anaerobic microbial degradation of ethanol within the capillary fringe and

conversion to methane.

Attenuation of Contaminants within the Capillary Fringe

Powers(2001)

3 2

1

DISSOLVED OXYGEN (mg/L)

ETHANOL (g/L)

25

3

4

5 10

DISSOLVED ORGANIC CARBON (mg/L)

BENZENE (g/L)

0.5

4 15

Phase 2: Preliminary Site Results• Small amounts of ethanol entered the aquifer at 1 well

location directly beneath the release.• The unsaturated zone is actively degrading ethanol in

the capillary fringe and methane is present in the underlying shallow groundwater.

• Most ethanol degradation appears confined to the immediate vicinity of the derailment. Soil-generated methane is likely partitioned into the shallow groundwater.

• Although DO and nitrate concentrations are low in the shallow groundwater, sulfate is unaffected which suggests that methanogenesis is not occurring.

Behavior of Ethanol • Residual ethanol and BTEX ponded on the tight,

wet ditch soils and was partially volatilized.• Leachates to the capillary fringe appeared

spatially limited to sloped areas beneath the derailed tankers.

• The high-clay content dry soils commonly are cracked and may have allowed preferential flow to infiltrate beneath the spill area.

• Small amounts of ethanol and BTEX were detected in the groundwater and are likely being consumed by degraders.

Preliminary Conclusions• Robust emergency response to denatured ethanol releases

at derailment sites lessens the likelihood of groundwater contamination.

• Excavation and SVE work well in gravelly soils.

• Spills on tight soils like those at S. Hutchinson, KS were primarily attenuated through volatilization.

• At sites that are not considered a threat to drinking water, natural attenuation has been allowed to run its course and ethanol and gasoline-contaminated groundwater has resulted.

Preliminary Conclusions

• Rail transport of ethanol is predicted to increase from ~6 billion gallons in 2006 to ~10 billion gallons in 2010 (minimum of 7.5 billion gallons – RFA of 2005).

• At least 4 of the 5 derailments discussed occurred on tracks that needed repairs.

• To reduce the risk of derailment many railroad spurs to rural towns in the Midwest corn belt need upgrading for increased traffic.

Recommendations

• Resample at S. Hutchinson in July

• Work jointly with Pinnacle Engineering Inc. Maple Grove, MN

• Study the consulting reports from the Balaton and Courtland sites

• Better understand the persistence of ethanol and BTEX in the capillary fringe

• Gain knowledge of the dynamics of the microbial consortia in the plumes

• Suggest a spectrum of remediation alternatives applicable to ethanol derailment sites with different risk levels.

Acknowledgments

• Bruce Bauman, American Petroleum Institute• Todd Sneller, Nebraska Ethanol Board• Eric Mork, ICM, Inc.• Greg Hattan, co-PI KDHE• Kenny Simmons, HAZ-MAT Response, Inc.• Jeff Toavs, Technologist • Mary Exner, co-PI UNL• Michael Hyman, co-PI NCSU