Surfactant Flushing
An Innovative Ground Water
Remediation Technology
Jeffrey H. Harwell
Asahi Glass Chair of Chemical Engineering
The University of Oklahoma, Norman
Principal, Surbec Environmental, LLC
Basics
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

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Release NAPL from aquifer pores
Direct and Indirect Food Additives
Surfactants pass EPA biodegradation testing
Used throughout the United States
US patents 6,913,419 and 7,021,863
What is a surfactant?



Molecule fits between
oil and water
Common and safe
Found in
–
–
–
–
Salad dressing
Toothpaste
Mouthwash
Shampoo
How does it work?
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
NAPLs contaminate ground water
Droplets become immobile
– Trapped by surface tension
– Force that traps water in a paper towel

Surfactants go to oil/water interface
– Lower surface tension
– Release droplets
– Like removing grease from pants in laundry

Newly mobile NAPL extracted with pumps
Trapped-drop . . . becomes released
…and is pumped to surface
Column
Comparison
Ground Water
Food
Surfactant
Laundry
Surfactant
“Designer” blend of surfactants
7 / 57
Trapping
Curves
8 / 57
Mobile Portion
of NAPL in
Pores without
Surfactant
System Capillary
Number without
Surfactant
9 / 57
Mobile Portion
of NAPL in
Pores with
Surfactant
System Capillary
Number with
Surfactant
System Capillary
Number without
Surfactant
Observations

Trapped NAPL can be mobilized by
– increasing water pore velocity
– increasing water viscosity
– lowering interfacial tension

Surbec reduces interfacial tension
– 3 to 4 orders of magnitude
– very low concentrations (< 1wt %)
How Is It Delivered?
Extraction Wells
NAPL Pool
Injection Wells
17.
0’
IW1
IW2
IW4
IW3
SB-4
18.
0’
EW1
IW5
EW2
IW6
EW3
IW7
IW8
IW9
SB-2
EW4
IW13
SB-1
IW10
SB-3
IW11 IW12
SB-5
IW14
EW6
IW15
IW20
IW21
IW24
EW9
EW5
IW16
IW17
IW18
IW19
IW22
EW7
IW23
EW8
IW25
IW26
IW27
IW28
5 PPM
SB-6
IW30
IW29
EW10
0’
Remediation Well System
Layout with Well Numbers
50’
IW31
EW11
100’
IW32
EW12
Surfactant Flushing
Integrated Process
AC
WASTE
STORAGE
O/W
Separator
Mixer
AS
Raw S
NAPL
RW
IW
Disposal