Perchlorate as an Example of Groundwater Contamination Arising from Dense Brines

James R. HuntUniversity of California at Berkeley

Based on the Ph.D. Thesis of Tracey C. Flowers

Currently at Exponent, Inc.

Research Supported by University of California Water Resources Center

National Institute of Environmental Health Sciences:Superfund Basic Research Program

Presentation Pathway•Perchlorate as a brine

•Other contaminants present in brines

•Two field examples

•Brine transport processes – experimental

•Brine transport processes – predictions

•Return to field examples

•Summary

Ammonium Perchlorate: NH4ClO4

Released during production and rocket hogging out

Solubility: 180 g ClO4-/L

Saturated Fluid Density: 1.11 g/cm3

Largely non-reactive (tracer)

California Public Health Goal: 6 μg/L

Volume required to dilute saturated solution to Public Health Goal:

7103/6/180

×=≈LgLg

μ

Occurrence Source Density[g/cm3] Cont.

Reported Conc. MCL

Dilution Required

Acid Mine H2SO4 1.4 As 340 mg/L 10 μg/L 105

Landfill Leachate TDS 1.05 Vinyl

Chloride 40 mg/L 2 μg/L 104

90Sr 4 x 1010 Bq/L 10 Bq/L 1010Nuclear Fuel

Reprocessing NaNO3 1.5137Cs 8 x 109 Bq/L 50 Bq/L 108

Solid Rocket Fuel NH4ClO4 1.11 ClO4

- 180 g/L(solubility)

6 μg/ L 107

Common Brine Occurrences

Example 1: Olin Facility, Morgan Hill, CA

Santa Clara Valley Water District

Example 2:

Hinkley, CA Natural Gas Compressor Station, Chromium Groundwater Plume, May 1988

Ecology and Environment, Inc.

UAquifer

Source

Less Permeable Lens

Brine Transport: Emplacement

U

Emplaced Brines

Dilute Plumes

Brine Transport: Release

Displacing Fluid

ρtop, μD

Resident Fluidρbot μR

U

Hill’s 1952 Stability Analysis

1μμ

Uμn)ρ(ρkg

D

R

D

topbot −>−

Criterion for Stable Displacement

1MNG −>

0

1

2

3

-2 -1 0 1 2NG

M

Stabilized byViscosity

Stabilized by Gravity

Critical GravityNumber: NG,c = M - 1

Hill’s Stability Diagram for Brines

0

1

2

3

0.00010.011100 - -- -0

1

2

3

0.0001 0.01 1 100 10000

Biggar and Nielsen [1964]Slobod and Howlett [1964]Elrick et al. [1966]Krupp and Elrick [1969]Starr and Parlange [1976]Aachib [1987]Bues and Aachib [1991]Kempers and Haas [1994]Harmon et al. [1999]Schotting et al. [1999]Watson et al. [2002]Jiao and Hotzl [2004]Menand and Woods [2005]Stability Criterion

NG

M

Experimental Data on 1-D Miscible Displacement

0.0

0.2

0.4

0.6

0.8

1.0

0.8 0.9 1.0 1.1 1.2Pore Volumes

C/C

o

NG M Dpm/DT -0.11 0.47 1.09 -0.94 0.47 4.5 -0.11 1.0 1.06

Example Breakthrough Curves (T. Flowers thesis)

0.1

1

10

100

1000

0.00010.011100NG

Dpm

/DT

Biggar and Nielsen [1964]Slobod and Howlett [1964]Elrick et al. [1966]Krupp and Elrick [1969]Starr and Parlange [1976]Aachib [1987]Harmon et al. [1999]Jiao and Hotzl [2004]Menand and Woods [2005]

- -- -0.01

0.1

1

10

100

1000

0.0001 0.01 1 100 10000NG

Dpm

/DT

Biggar and Nielsen [1964]Slobod and Howlett [1964]Krupp and Elrick [1969]Starr and Parlange [1976]Bues and Aachib [1991]Kempers and Haas [1994]Harmon et al. [1999]Schotting et al. [1999]Watson et al. [2002]Jiao and Hotzl [2004]Menand and Woods [2005]

Normalized 1-D Dispersion from the Literature

Freshwater Brine

Pulseless Flow Pump

Sensor Block Conductivity MeterWaste

Experimental Program

Diameter[cm]

Length [cm]

Permeability[10-8 cm2]

3.2 97 935.8 98 925.8 96 353

Column Properties

0.95

1.05

1.15

1.25

1.35

1.45

0 200 400 600Concentration [g L-1]

Den

sity

[g

cm-3

]

0

2

4

6

8

10

Visc

osity

[cP

]

CaCl2 DensityCaCl2 ViscosityKCl DensityKCl Viscosity

Experimental Brines

52.1 g/L CaCl2108 g/L CaCl2157 g/L CaCl2208 g/L CaCl2263 g/L CaCl262.3 g/L KCl153 g/L KClCritical Gravity

0.001 0.01 0.1 1 10-0.001-0.01-0.1-1-100.0

0.5

1.0

1.5

2.0

2.5

NG

MExperimental Conditions

0.1

1

10

100

0.010.1110NG

Dpm

/DT

52.1 g/L CaCl2103 g/L CaCl2157 g/L CaCl2208 g/L CaCl2263 g/L CaCl262.3 g/L KCl153 g/L KCl

-- - -

Experimental Results

0.1

1

10

100

0.010.1110 NG

Dpm

/DT

52.1 g/L CaCl2157 g/L CaCl2263 g/L CaCl262.3 g/L KCl153 g/L KCl

263 g/L CaCl2 NG,c

157 g/L CaCl2 NG,c 52.1 g/L CaCl2 NG,c

- - - -

Experimental Data, Higher Permeability Column

0.1

1

10

0.01 0.1 1 10NG

Dpm

/DT

52 g/L CaCl2108 g/L CaCl2157 g/L CaCl2208 g/L CaCl2263 g/L CaCl262.3 g/L KCl153 g/L KCl

Experimental Data

0.1

1

10

0.01 0.1 1 10NG

Dpm

/DT

52 g/L CaCl2157 g/L CaCl2263 g/L CaCl262.3 g/L KCl153 g/L KCl

NG,c : 263 g/L CaCl2

NG,c :157 g/L CaCl2

NG,c: 52 g/L CaCl2

263 g/L CaCl2

157 g/L CaCl2

52 g/L CaCl2

Selected Experimental Data

Koval (1963) Asymptotic Prediction

UAquifer

Source

Less Permeable Lens

Brine Transport: Emplacement

U

Emplaced Brines

Dilute Plumes

Brine Transport: Release

U

H

L

bEmplaced Brine

Aquifer

Geometry for Diffusion Controlled Release Model

ConfiningLayer

x

z

1.E-11

1.E-09

1.E-07

1.E-05

1.E-03

1.E-01

0.001 0.01 0.1 1 10 100 1000

Nor

mal

ized

Con

cent

ratio

n

Time [yr.]

Dilution = 105 (Acid Mine) ~ 30 years

Dilution = 107 (Solid Rocket Fuel) ~ 80 years

Dilution = 109 (Nuclear Fuel Reprocessing) ~ 150 years

Predictions of Downstream Concentration

Spill Geometry

Spill Length L 20 m

Aquifer Height H 5 m

Confining Layer Depth b 1 m

Velocity U 1 m day-1

Porous Media Diffusivity Dmol 0.009 m2 yr-1

Hinkley Chromium Plumes

1988

CH2M Hill

2002

MW-19

Groundwater Elevation at MW-19, Hinkley, CA

0.0

1.0

2.0

3.0

4.0

5.0

D-93 D-95 D-97 D-99 D-01 D-03

Date

Tota

l Cr

[mg/

L]

MW-11B

MW-15

Chromium in Groundwater at Hinkley, CA

Summary

•Dense brines are released into the subsurface

•Brines sink

•Brines mix

•Contaminants within brines are released slowly into flowing groundwater

•Source identification and control are essential

References:

Flowers and Hunt (2000) Perchlorate in the Environment, E. T. Urbansky, ed.

Flowers and Hunt (2007) Water Resources Research