Geoffrey Delin and William Geoffrey Delin and William HerkelrathHerkelrathU.S. Geological SurveyU.S. Geological Survey

Scott Scott LounsburyLounsburyEnbridge Pipeline CompanyEnbridge Pipeline Company

USGS Toxics Substances Hydrology MeetingUSGS Toxics Substances Hydrology MeetingJanuary 26, 2009January 26, 2009

San Diego, CaliforniaSan Diego, California

Effects of Remediation at the Effects of Remediation at the Bemidji, Minnesota CrudeBemidji, Minnesota Crude--Oil Oil

Spill SiteSpill Site

OutlineOutline-- Pipeline rupture and initial remediationPipeline rupture and initial remediation

(1979)(1979)

-- Second phase of remediation (1998Second phase of remediation (1998--2004)2004)

-- USGS monitoring of the remediation USGS monitoring of the remediation

-- Introduction to other Bemidji presentationsIntroduction to other Bemidji presentations

Oil in spray zone

CrudeCrude--oil pipeline broke in August, 1979oil pipeline broke in August, 1979High pressure (3.5 High pressure (3.5 MPaMPa or ~500 psi), or ~500 psi), 86 cm (3486 cm (34--inch) inch) diameter pipeline diameter pipeline ruptured on ruptured on August, 20, 1979 August, 20, 1979 spilling 1,670 mspilling 1,670 m33

(10,500 barrels) of (10,500 barrels) of crude oil in an crude oil in an uninhabited area uninhabited area near Bemidji, near Bemidji, MinnesotaMinnesota

Minnesota

Bemidji Site

Site of pipelinerupture 1979

aerialphoto

Oil sprayzone

Crude oil sprayed over large areaCrude oil sprayed over large area

Oil pooled in low lying areas (≈2,000 m2) and sprayed over area of 6,500 m2

to the southwest of the pipeline that became known as the ‘spray zone’.

Views of Trench and PipelinesViews of Trench and PipelinesPipeline rupture site

Pipelines are ~3 m below land surface

Bemidji Crude Oil Spill SiteBemidji Crude Oil Spill SiteN

Research Site

Bemidji

Minnesota

North oil pool, 8/98

Observation well

Excavatedarea

Site ofpipeline

break, 8/79

Railroad tracks

Oil pipelines

Spray zone

Wetland0 80

50 100 150 200 250 Feet

20 40 60 100 Meters

0

0

South oil pool, 8/98Middle oil pool, 8/98

Generalized direction of ground-water flow

Oildrainage

area

Well 981

Remediation Remediation efforts led to efforts led to removal of ~ removal of ~ 75% of oil from 75% of oil from site (about 417 site (about 417 mm33 or 2,600 or 2,600 barrels of oil barrels of oil remained)remained)

1991 aerial photo

USGS & University Research1983 – Present

Many Research Groups Have Many Research Groups Have Been Involved at Bemidji SiteBeen Involved at Bemidji Site

Numerous USGS research teamsUniversity of British ColumbiaUniversity of ColoradoUniversity of KansasUniversity of MassachusettsUniversity of MinnesotaStanford UniversityUniversity of TexasUniversity of VirginiaUniversity of WaterlooBemidji State University Indiana UniversityEnbridge Pipeline CompanyMinnesota Pollution Control Agency

Significant Research HighlightsSignificant Research Highlights

Bemidji site one of first field sites where Bemidji site one of first field sites where natural attenuationnatural attenuation demonstrateddemonstratedResults and technologies transferredResults and technologies transferred to to numerous other sitesnumerous other sitesOil degradation is greater in areas of Oil degradation is greater in areas of increased rechargeincreased rechargeRedoxRedox processes change over small vertical processes change over small vertical intervalsintervalsSuccession from ironSuccession from iron--reducing to reducing to methanogenic microbial communities = slight methanogenic microbial communities = slight growth of the plume growth of the plume

Renewed Remediation Renewed Remediation –– 19981998

Well 981

Observation well

Excavatedarea

Site ofpipelinebreak

Infiltrationgallery Remediation

buildingOil

drainagearea

Oil pipelines

Spray zone

Wetland0 80

50 100 150 200 250 Feet

20 40 60 100 Meters

0

Generalized direction of ground-water flow

South oil poolFormer railroad tracks

Middle oil pool

North oil poolXX

XX

X

Remediationwell

Second phase of

remediation began in

December 1998

Objective: to remove oil to a sheen on water table in the wells

Predicted Remediation EffectsPredicted Remediation Effects

Total volume of oil per unit area prior to remediation, cm

Likely amount that can be recovered, cm

34

2

10

18

26

102

-60 -50 -40 -30 -20 -10 0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

X IN METERS

Y IN

MET

ER

S

Observation well

2

-60 -50 -40 -30 -20 -10 0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

X IN METERS

Y IN

MET

ER

S

Remediation well

147,000 L of oil, North Pool

37,000 L of oil, ~25% recoverable

Herkelrath, 1999

Installing Remediation Well Installing Remediation Well RWRW--1S, looking NW1S, looking NW

Pipeline rupture site

South pool

Hydrophobic soilin spray zone

DualDual--Pump Remediation SystemPump Remediation System

Skimmerpump

Remediationwell

To storagetank

Land surfaceLand surface

Unsaturated zoneFree product (crude oil)Saturated zone

LEGEND PUMPS ONPUMPS OFF

To storagetank

To separatortank and

infiltrationgallery

To separatortank and

infiltrationgallery

Remediationwell

Skimmerpump

Ground water pump

Ground water pump

Water TableWater Table

North Pool North Pool Remediation Remediation

WellsWells

RW-1N

RW-2N

Total pumping rate of water from all wells ~113 L/min (~30 gpm)

Remediation Remediation Building,Building,May 1999May 1999

Pipeline rupture site(looking NE)

Collaborative AgreementEstablished in 2008Established in 20082020--year duration year duration PartnersPartners: : 1. Scientists at the USGS and academic institutions, 1. Scientists at the USGS and academic institutions, 2. Enbridge pipeline company, 2. Enbridge pipeline company, 3. Beltrami County, and 3. Beltrami County, and 4. Minnesota Pollution Control Agency 4. Minnesota Pollution Control Agency Primary PurposePrimary Purpose: To promote research and : To promote research and educational opportunities educational opportunities Secondary PurposeSecondary Purpose: To test the effects of in: To test the effects of in--situ situ alternative remediation strategies at the site alternative remediation strategies at the site

Problems:Problems:LNAPL recovery, although common, is LNAPL recovery, although common, is expensive ($100,000expensive ($100,000’’s / year)s / year)BTEX analyses to evaluate contaminant BTEX analyses to evaluate contaminant migration and effects of remediation are also migration and effects of remediation are also expensiveexpensive

Simple, lessSimple, less--expensive methods are needed expensive methods are needed to evaluate remediation effectsto evaluate remediation effectsFew of these remediation studies are Few of these remediation studies are documented in the literaturedocumented in the literature

Opportunities:Opportunities:

LNAPL RemediationLNAPL Remediation

USGS Research ObjectiveUSGS Research Objective: : Evaluate effects of the oilEvaluate effects of the oil--recovery scheme using simple recovery scheme using simple methodsmethods

HypothesisHypothesis:: The renewed The renewed remediation would have an remediation would have an insignificant effect on oil insignificant effect on oil distribution, rates of volatilization, distribution, rates of volatilization, and rates of biodegradation. and rates of biodegradation.

Oil Thickness Measurements Oil Thickness Measurements

Using an oil-interface meter

Field Parameter Field Parameter Sampling Sampling

Well 981

Observation well

Excavatedarea

Site ofpipelinebreak

Infiltrationgallery Remediation

buildingOil

drainagearea

Oil pipelines

Spray zone

Wetland0 80

50 100 150 200 250 Feet

20 40 60 100 Meters

0

Generalized direction of ground-water flow

South oil pool Former railroad tracks

Middle oil pool

North oil poolXX

XX

X

Remediationwell

North pool North pool transecttransect

North Pool Transect of WellsNorth Pool Transect of WellsTo To ““Unnamed lakeUnnamed lake””

Vapor Transport MonitoringVapor Transport Monitoring

Well 981

Observation well

Excavatedarea

Site ofpipelinebreak

Infiltrationgallery Remediation

buildingOil

drainagearea

Oil pipelines

Spray zone

Wetland0 80

50 100 150 200 250 Feet

20 40 60 100 Meters

0

Generalized direction of ground-water flow

South oil pool Former railroad tracks

Middle oil pool

North oil poolXX

XX

X

Remediationwell

Periodic to annual sampling

Vapor samples analyzed in field using GC

Transect of vapor

wells

Vapor wellVapor well

Conceptual Vapor ModelConceptual Vapor Model

Residual oil

saturation UNSATURATED ZONE

CAPILLARY ZONE

SATURATED ZONE ANDDISSOLVED PLUME

VaporwellLand surface

Vaporprobe

Hydrocarbonflux

Methaneflux

Oxygenflux

CO flux

2

CRUDE OIL IN SMEAR ZONE AND FLOATING ON WATER TABLE

z6

z5

z4

z3

z2

z1

z0

FICK’S LAW

J = -D dGkkk

dzBiodegradation

Sand andgravelaquifer

Sorptio

n

Volatilization

1985 Methane Vapor, % of Atmospheric

Meters from center of oil

Elev

atio

n, m

eter

s

Floating oil

Upcoming Bemidji-Related Presentations

ORALS Technology transfer to Mandan, ND diesel spill siteLong term fate of intractable LNAPLsBemidji science drives model developmentTechnology transfer to Cass Lake, MN crude-oil spill site

POSTERSIron-reducing, in-situ microcosmTemperature as an indicator of microbial degradation Predicted effects of renewed remediationEffects of renewed remediationMethanogenic biodegradation of hydrocarbonsPush-probe reconnaissance (new tools)Reactive gas transport modeling Loss of volatile hydrocarbons in the oil: 1985 to 2008

Questions?