case study: permanganate applied to vocs in fractured shale · 1 case study: permanganate applied...
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Case Study:Permanganate Applied to VOCs
in Fractured ShaleBeth L. Parker, Ph.D.Beth L. Parker, Ph.D.Department of Earth Sciences
University of Waterloo
Presented at the EPA Symposium in ChicagoDecember 12, 2002
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Research Collaborators� Dr. Tom Al
� University of New Brunswick� Dr. Ulrich Mayer
� University of British Columbia� Drs. Ramon Aravena and John Cherry
� University of Waterloo� Kenneth Goldstein, CGWP
� Malcolm Pirnie, Inc� Grant Anderson, P.G.
� U.S. Army Corps of Engineers
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Watervliet Arsenalin New York State
Watervliet Arsenal
TroyHudson River
Shale
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Hudson River
Watervliet ArsenalBuilding 40 Area
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FlowOverburden
Bedrock
PCE
adapted from Mackay and Cherry, 1989
DNAPLDNAPL Passed Through Overburden Into Shale
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The Problem
� Chlorinated ethenes � as high as 150 mg/L
� Contamination down to 150 ft. bgs
� All VOC mass in fractured shale
� AOC is 200 ft west of Hudson River
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Study Area
AW-MW-59
N
Building 40
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Identification of Major TransmissiveZones Using Hydro-geophysics
USGS, 2001
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Major Transmissive Zone Identified
USG
S, 2
001
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93,600
5,310
5,150
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MW-71
Fractures, Transmissive Zones, and Total VOCs from PACKER TESTINGPACKER TESTING
Leakage
µg/L
USGS, 200110
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PCE and Degradation Products in Shale
South North
From packer test intervalsduring drilling
PCE
DCE
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Interconnected Fracture Networkwith Two Major Transmissive Zones
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Cross-section view
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DNAPL was Initially Distributedin Many Fractures
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ILLUSTRATION OF MATRIX POROSITY
A
Microscopicview of rock
matrix
mineral particleDETAIL A
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DNAPL Phase Initially Resides within Fractures
Fracture Aperture2b
Fracture Spacing
H O2
φfφm DNAPL
Matrix porosity is1000 times greater than
fracture porosity
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DNAPL Disappearance by DiffusionParker et al. (1994)
Fracture Aperture2b
FractureSpacing
φfφm
H O2
DNAPLφf φm
DissolvedPhase
φfφm
DissolvedPhase
Early Intermediate Later Time
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Snake Hill Shale FormationWatervliet Site
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Core Hole In Source Zone
vadosezone
groundwaterzone
coredhole
B.L. Parker, 200018
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Diffusion Into Rock Matrix
Porous Rock Matrix
DiffusionHalo
Fracture
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0 1 10 100TCE mg/L
rock core
non-detect
Fractures withTCE migration
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fractures coresamplesanalyzed
cored hole
Core Sampling forMigration Pathway Identification
B.L. Parker, 200020
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Core Diameter3.2 Inches
Sample Length~Two InchesOverview
of theRock Core
Method
Parker and Colleagues 199721
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Two Rock CrushersTwo Rock Crushers
Rock Crusher
Crushing Cell
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MW-74Dec. 2001 (preliminary data)
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1600.01 0.1 1 10 100 1000 10000 10000
01E+06
conc. VOC (ug/L)
dept
h (ft
)
PCETCEc-DCE
PCE
solu
bilit
y (2
40 m
g/L)
Rock CoreProfileDec 2001
Pre-KMnO4Injection
CMT AqueousPORTS Concentrations
(Feb. 2002)
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PCE � 8 ug/LTCE � 5 ug/Lc-DCE � 350 ug/L
PCE � 4 ug/LTCE � NDc-DCE � 1088 ug/L
PCE � 458 ug/LTCE � 123 ug/Lc-DCE � 2802 ug/LPCE � 9183 ug/LTCE � 382 ug/Lc-DCE � 524 ug/LPCE � 13,988 ug/LTCE � 3,699 ug/Lc-DCE � 15,155 ug/LPCE � 172 ug/LTCE � 259ug/Lc-DCE � 11,745 ug/L
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WESTBAY ® MP SYSTEM
2.5 ft.
2.5 ft.
Tripod
Cable ReelPressure Probe
Sample Bottle
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SOLINST CMT ® SYSTEM
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Site Conceptual Model
� VOC migration occurs in a large number of interconnected fractures
� Nearly all VOC mass resides in the rock matrix rather than in the fractures
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It is well established that permanganate completely
destroys chlorinated ethenes
However, to do so,it must be delivered to the
contaminant mass
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Can permanganate be effective for remediatingchlorinated ethenes in
fractured sedimentary rock?
Important factors:� Delivery throughout fracture network� Diffusion rates into rock matrix� Oxidant Demand of Shale
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KMnO4 Injections at Watervliet
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71 74
Potassium Permanganate Injection597675 65 34
~145 feet bgs
Phase 1Phase 1injectioninjection
Phase 2Phase 2injectioninjection
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PILOT STUDY RESULTS in 2002
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Treatment Approach Permanganate
� Permanganate oxidizes chlorinated ethenes
Solvent + MnO4- MnO2(s) + Cl- + Acid
� 13C / 12C and Chloride used to confirm destruction
� Stable chemistry in subsurface allows time for diffusion into matrix
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Remediation in Fractured Porous Media
Treatment zone
EarlyTime
LaterTime
KMnO4 in fracture
Contaminated clay/rock
Contaminated clay/rock
B.L. Parker, 1993
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In Situ Oxidation in Fractured Porous Media
� Diffusion of both reactants occurs in opposite directions
� Readily destroys sorbed phase contaminants
Greatly reduces time scale for remediation
B.L. Parker, 1993
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Analogy to Fractured Shale
Results from Permanganate Field Tests
in Marine Clay
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Oxidized zone shows extent of diffusion invasion and treatment by KMnO4
B.L. Parker, 1996
Invasion frontTop of clay
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3.8
3.9
4.0
4.10 5 10 15
KMnO4 in pore water (g/l)
Depth(m)
147 daysPease ISI-6
KMnO4 Profile in Clay
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Combined Profiles in Clay
3.8
3.9
4.0
4.10 5 10 15
Concentration
Depth(m) KMnO4
TCE
147 daysPease ISI-6
Reaction interface
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Snake Hill Shale FormationWatervliet Site
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Permanganate Diffusion into Matrix from Fracture
z
x
y
diffusion
2b = fracture aperture
mass mass
x x+
C/Co
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Elemental Manganese Profiles in ShaleTransects Normal to Fractures Propagating
in from Surface of Rock Sample
0
500000
1000000
1500000
2000000
2500000
0 0.2 0.4 0.6 0.8 1 1.2
Distance (mm)
Transect #1
Transect #2
Fracture
Fracture
Shale sample in 10 g/L KMnO4 solution for ~6 weeks
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How long will MnO4 take to remediate the source zone?
� Answer being sought using~ field data~ laboratory tests~ numerical models
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Preliminary MIN3P SimulationsWatervliet Arsenal
3D multicomponent reactive transport model
Model developed byDr. Ulrich Mayer (1999)
Now being modified for permanganate oxidation
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MIN3P Simulation
� Simulate 1D MnO4- invasion into shale matrix
where PCE has been diffusing in for 40 years to examine rates of matrix clean-up
� Parameters:� Site-specific φ, De, foc� MnO4
- R = 1� PCE R = 220 (estimated using foc=0.5%)� Source [ PCE ] = 150 mg/L for 40 years� Injection [ KMnO4 ] = 5 g/L
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Chloride Diffusion Test Cell for Rock
Golder Associates, Toronto45
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Initial Condition40 years PCE Diffusion-In
MIN3P Model � Snake Hill Shale
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Matrix Profiles after 1 yearMnO4
- InjectionMIN3P Model � Snake Hill Shale
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Matrix Profiles after 2 yearsMnO4
- InjectionMIN3P Model � Snake Hill Shale
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Matrix Profiles after 5 yearsMnO4
- InjectionMIN3P Model � Snake Hill Shale
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Partial Mass Destruction
Greatly diminishes VOC mass flux into fracture network
after permanganate is gone
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PCE flux to fracture afterpartial permanganate treatment
Frac3DVS Modeling Log - Log Scale
0.001
0.01
0.1
1
10
0.001 0.01 0.1 1 10 100
Time (years)
Flushing only1 yr2 yr5 yr10 yr20 yr
KMnO4
RemediationTimes
No MnO4 Case
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Preliminary Conclusions
Permanganate�
� Diffuses and reacts in low K matrix
� Prevents release of mass from matrix to flowing
groundwater while present in fractures
� Greatly reduces magnitude of flux from matrix
even after partial treatment
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How do we know that VOCsare being destroyed ?
� Chloride increases at many locations
� Change in carbon isotope ratio of PCE
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ON-GOING WORK
� Rebound monitoring after pilot injections
� Permanganate invasion tests� Laboratory samples� Field cores
� Reactive transport modeling� Single fractures and fracture networks
� Design of full-scale system and monitoring
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Acknowledgements� Project Contributors:
~ Steven Chapman and Martin Guilbeault (UWaterloo)~ Daria Navon and Andrew Vitolins (Malcolm Pirnie)~ Stephen Wood (U.S. Army Corps of Engineers)~ JoAnn Kellogg (Watervliet Arsenal)~ John Williams and Fred Paillet (U.S.G.S)
� Funding:~ U.S. Army Corps of Engineers~ Solvents-In-Groundwater Research Program
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The End