University of Southern California Dissertations and Theses

Electroremediation of offshore muds contaminated with heavy metals

(USC Thesis Other)

Electroremediation of offshore muds contaminated with heavy metals

PDF

Download a page range

Download transcript

Copy asset link

Request this asset

Transcript (if available)

Content

ELECTROREMEDIATION OF OFFSHORE MUDS
CONTAMINATED WITH HEA VY METALS

by

Sanghee Shin

A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(ENVIRONMENTAL ENGINEERING)

December 2011

Copyright 2011 Sanghee Shin
ii

Dedication

to my parents –
Kwag-Ok and Min-Ja Shin

iii

Acknowledgments

I would like to thank Professor Najmedin Meshkati, my advisor and chair of Ph.D.
committee for his support and guidance. He has always guided me to organize my
thoughts during my research. He deserves the highest of praise.
Dr. George V. Chilingar helped me to obtain a secure foundation of knowledge in
the fields of Environmental and Petroleum Engineering. Out of classrooms, he showed me
how a scholar should live his daily life. I was really honored to have a chance to work with
him closely.
I also would like to thank to my other Ph.D. committee members, Professors Jiin-
Jen Lee, Vincent W. Lee, Jean-Pierre Bardet, Muhammad Sahimi, and Solomn Golomb
and outside committee members Sibel Pamukcu and Muhammad Haroun.
Dr. Sibel Pamukcu gave me a chance to work with her at Lehigh University and
thoroughly trained me in her electrokinetics laboratory. She shared with me her unique
knowledge of electrokinetics. Dr. Muhammad Haroun kindly invited me to his
electrokinetics laboratory at the Petroleum Institute of Abu Dhabi, UAE, where I worked
for six months. He was an excellent mentor, teacher and friend.
I would also like to extend special thanks to my family for their support and
encouragement in completing this research. My parents, Kwang-Ok and Min-Ja Shin have
provided their endless support throughout my study. Without their support, I would not
have been able to study and do research. My brother, Sang-Kyun Shin, deserves my
special thanks for his words of encouragement, while I was studying at USC.
iv

Table of Contents

Dedication ii
Acknowledgments iii
List of Tables vi
List of Figures vii
Abstract xv
Chapter 1: Introduction 1
1.1 Heavy Metals 2
1.2 Electrokinetics 4
1.3 Theoretical Analysis 15
1.4 Transport of Contaminants in Soils on Application of D.C. Current 19
1.5 Multicomponent Cleanup Technologies and Examples of Their
Application in situ 23
1.6 Dewatering of Soils 26
1.6.1 Field Applications of Electrokinetics 27
1.7 Electrochemical Treatment of Soil and Weak Rocks 29
1.8 EEOR (Electrical Enhanced Oil Recovery) 32
1.9 Economic Feasibility 36

v

Chapter 2: Apparatus 41
2.1 Sampling Area in Abu Dhabi,U.A.E 48
2.2 Particle Size Distributions of Samples 52
2.3 Preparation of Samples 58
Chapter 3: Experimental Results 63
3.1 Removal of Heavy Metals upon Application of D.C. Current Using
Different V oltage Gradients 64
3.2 Comparison of Removal of Heavy Metals after 48 and 72 hours 128
3.3 Effect of Partial Chlorine Gas Removal 143
3.3.1 Partial Chlorine Gas Removal 143
Chapter 4: Conclusions 170
References 172
Appendix : New Technology (Electrokinetics) to Greatly Improve Acidizing of
Carbonate Reservoir Rocks 180
Introduction 181
Electrokinetics 183
Deployment System for Enhanced Acidizing 185
Conclusions 186
Appendix References 187

vi

List of Tables

2-1Sediment classification according to USDA sediment textural system
(Modified). 54
2-2 Particle size distribution of sample collected in Area No.1. 55
2-3 Particle size distribution of sample collected in Area No.2. 55

vii

List of Figures

1-1 Schematic diagram of electrokinetic double layer. 5
1-2 Electric double layer at the interface between a solid and liquid. 7
1-3 Schematic representation of zeta potential ( ξ). 11
1-4 Electrode arrangement for selective ion-drive. 31
1-5 Relationship between potential gradient and normalized electrokinetically
induced fluid flow, for different silica--clay mineral mixtures. 35
2-1 A schematic diagram showing the first apparatus and connections used in
Petroleum Engineering Laboratories at the University of Southern California. 42
2-2 Schematic diagram of second apparatus and connections used in Petroleum
Engineering Laboratories at the University of Southern California. 43
2-3 Electrokinetic apparatus, DC power source and graduated glass burettes to
measure both inflow and outflow at each of the two electrode ends. 44
2-4 Schematic diagram of glass elektrokinetic cell. 45
2-5 Photograph of electrokinetic apparatus and multimeter for measuring voltage,
current and resistance. 46
2-6 Apparatus used in electroremediation of heavy metals from offshore muds and
sediments with partial chlorine gas removal equipment. 47
2-7 Sample location No. 1 near the refinery industrial area. 49
2-8 Sample No. 2 location near the sewer outlet. 50
viii

2-9 Sampling area near the port (Sample No.3) in Abu Dhabi, U.A.E. 51
2-10 Sediment (soil) texture triangle (USDA). 54
2-11 Particle size distribution curve of sample collected in Area No.1. 56
2-12 Particle size distribution of sample collected in Area No.2. 57
2-13 The consolidation equipment setup used to prepare samples. 61
2-14 Sampling locations. 62
3-1 Concentration of Al upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 65
3-2 Concentration of Al upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 66
3-3 Concentration of Al upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 67
3-4 Concentration of As upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 68
3-5 Concentration of As upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 69
3-6 Concentration of As upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 70
3-7 Concentration of Cs upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 71
3-8 Concentration of Cs upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 72
3-9 Concentration of Cs upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 73
3-10 Concentration of Cr upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 74
ix

3-11 Concentration of Cr upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 75
3-12 Concentration of Cr upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 76
3-13 Concentration of Se upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 77
3-14 Concentration of Se upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 78
3-15 Concentration of Se upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 79
3-16 Concentration of Pb upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 80
3-17 Concentration of Pb upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 81
3-18 Concentration of Pb upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 82
3-19 Concentration of Zn upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours. 83
3-20 Concentration of Zn upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours. 84
3-21 Concentration of Zn upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours. 85
3-22 Concentration of Al upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 86
3-23 Concentration of Al upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 87
3-24 Concentration of Al upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 88
3-25 Concentration of As upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 89
3-26 Concentration of As upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 90
x

3-27 Concentration of As upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 91
3-28 Concentration of Cr upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 92
3-29 Concentration of Cr upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 93
3-30 Concentration of Cr upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 94
3-31 Concentration of Cs upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 95
3-32 Concentration of Cs upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 96
3-33 Concentration of Cs upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 97
3-34 Concentration of Se upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 98
3-35 Concentration of Se upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 99
3-36 Concentration of Se upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 100
3-37 Concentration of Pb upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 101
3-38 Concentration of Pb upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 102
3-39 Concentration of Pb upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 103
3-40 Concentration of Zn upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours. 104
3-41 Concentration of Zn upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours. 105
3-42 Concentration of Zn upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours. 106
xi

3-43 Concentration of Al upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 107
3-44 Concentration of Al upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 108
3-45 Concentration of Al upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 109
3-46 Concentration of As upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 110
3-47 Concentration of As upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 111
3-48 Concentration of As upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 112
3-49 Concentration of Cr upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 113
3-50 Concentration of Cr upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 114
3-51 Concentration of Cr upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 115
3-52 Concentration of Cs upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 116
3-53 Concentration of Cs upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 117
3-54 Concentration of Cs upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 118
3-55 Concentration of Se upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 119
3-56 Concentration of Zn upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 120
3-57 Concentration of Se upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 121
3-58 Concentration of Pb upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 122
xii

3-59 Concentration of Pb upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 123
3-60 Concentration of Pb upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 124
3-61 Concentration of Zn upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours. 125
3-62 Concentration of Zn upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours. 126
3-63 Concentration of Zn upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours. 127
3-64 Concentration of Al upon EK Treatment after 48 hours; length of core = 10 cm. 129
3-65 Concentration of Al upon EK Treatment after 72 hours; length of core = 10 cm. 130
3-66 Concentration of Cr upon EK Treatment after 48 hours; length of core = 10 cm. 131
3-67 Concentration of Cr upon EK Treatment after 72 hours; length of core = 10 cm. 132
3-68 Concentration of Cs upon EK Treatment after 48 hours; length of core = 10 cm. 133
3-69 Concentration of Cs upon EK Treatment after 72 hours; length of core = 10 cm. 134
3-70 Concentration of Se upon EK Treatment after 48 hours; length of core = 10 cm. 135
3-71 Concentration of Se upon EK Treatment after 72 hours; length of core = 10 cm. 136
3-72 Concentration of Cr upon EK Treatment after 48 hours; length of core = 20 cm. 137
3-73 Concentration of Cr upon EK Treatment after 72 hours; length of core = 20 cm. 138
3-74 Concentration of Cs upon EK Treatment after 48 hours; length of core = 20 cm. 139
xiii

3-75 Concentration of Cs upon EK Treatment after 72 hours; length of core = 20 cm. 140
3-76 Concentration of Zn upon EK Treatment after 48 hours; length of core = 20 cm. 141
3-77 Concentration of Zn upon EK Treatment after 72 hours; length of core = 20 cm. 142
3-78 Change in pH at the anode and cathode with EDTA acid application. 145
3-79 Five copper rings were mounted in mud samples. 146
3-80 Variation of voltage with time for samples No.1 and No.2.
Sample length = 30 cm; treatment time= 24 hours. 150
3-81 Variation of power with time for samples No.1 and No.2.
Sample length = 30 cm; treatment time= 24 hours. 151
3-82 Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 152
3-83 Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 153
3-84 Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 154
3-85 Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 155
3-86 Concentration of Cr upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 156
3-87 Concentration of Cr upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 157
3-88 Concentration of Cs upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 158
3-89 Concentration of Cs upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 159
3-90 Concentration of Zn upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 160
xiv

3-91 Concentration of Zn upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours. 161
3-92 Variation of voltage with time for samples No.3 and No.4.
Sample length = 30 cm; treatment time = 40 hours.
(with two 8-hour interruptions.) 162
3-93 Variation of power with time for samples No.3 and No.4.
Sample length = 30 cm; treatment time = 40 hours.
(with two 8-hour interruptions.) 163
3-94 Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours.
(with two 8-hour interruptions.) 164
3-95 Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours.
(with two 8-hour interruptions.) 165
3-96 Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours.
(with two 8-hour interruptions.) 166
3-97 Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours.
(with two 8-hour interruptions.) 167
3-98 Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours.
(with two 8-hour interruptions.) 168
3-99 Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours.
(with two 8-hour interruptions.) 169
A-1 Electrodes arrangement for acidizing operation. 185

xv

Abstract

The electroremediation process requires much needed research work to be optimized for
up-scaling and improving economic efficiency. This is particularly true when applying the
technology to highly heterogeneous and complex mineralogy materials such as offshore
sediments and muds. Laboratory batch tests were performed on field retrieved specimens
of contaminated offshore muds near Abu Dhabi Ports of United Arab Emirates. The
influence of various process parameters that determine the optimum operating conditions
and sustainable enhancement of electrokinetic remediation was investigated. Excellent
results of decontamination of seven heavy metals were achieved.
The removal of heavy metals by management of the in-situ chlorine gas (Cl
2
)
production was also investigated. The tests showed a high removal efficiency of heavy
metals at the cathode end of cores after 24 hours of EK application in the presence of
chlorine gas. In the initial tests, high electrokinetic flow potential was achieved; however,
high levels of chlorine gas were produced in high-salinity environments. This was
improved by controlling and maintaining a certain fraction of the chlorine gas (Cl
2
) in
place.
The pH was controlled by the identified optimum fraction of chlorine gas
maintained in-situ and transported from the anode to cathode. The transports of seven
heavy metals were evaluated in this study. The chlorine gas can have two impacts on the
xvi

transport of metals in the system. One is to oxidize the metal ions to a higher oxidation
state and the second is to form chloride complexes, which will have higher mobility in the
system. Determination of oxidation state and the subsequent metal chloride complex are
left for future research.
Electrokinetics is also proposed to improve acidizing operations, i.e., increase the
penetration distance. Aqueous solutions of hydrochloric acid (usually 15%) are pumped
into the carbonate formations to enlarge the pores and pre-existing fractures. However, the
penetration distance of acid is very short. By applying D.C. current, one can drive the acid
for long distances into the formation being acidized. According to Professor Chilingar, this
is a unique discovery which will lead to doubling the oil reserves in carbonate reservoirs
(60 % of World oil reserves reside in carbonates).

1

Chapter 1

Introduction

Contaminated muds are a tremendous threat to water resources, i.e., the groundwater and
seawater near the industrial areas. Huge volumes of offshore muds which are
contaminated with heavy metals (toxicity) require restoration.
The present dissertation is the continuation of research work presented in Ph.D
dissertation of Dr. Muhammad Haroun on the subject.
The writer worked six months at the electrokinetics laboratory of Dr. M. Haroun
at the Petroleum Institute, Abu Dhabi, U.A.E, to improve the electrokinetics methodology
and expand the experimental results. This resulted in publication of three articles. In
addition to Arabian-Persian Gulf offshore muds, the writer is experimenting with offshore
muds of California and Gulf coast, contaminated with heavy metals. The following
discussion is heavily based on those presented by Anbah et al. (1963) and Haroun (2009).
A review of theory behind the electrokinetics was presented by Haroun (2009).

2

1.1 Heavy Metals

"Heavy metals" are chemical elements with a specific gravity that is at least 5 times the
specific gravity of water. Some well-known toxic metallic elements are arsenic, sp. gr. =
5.7; cadmium, sp. gr. = 8.65; iron, sp. gr. = 7.9; lead, sp. gr. = 11.34; and mercury, sp. gr.
= 13.546 (Lide, 1992). Heavy metals become toxic when they are not metabolized by the
body and accumulate in the soft tissues. They may enter the human body through food,
water, air, or absorption through the skin when they come in contact with humans in
agriculture and in manufacturing, pharmaceutical, industrial, or residential settings.
Offshore muds are composed of clays, which are predominantly negatively
charged and, therefore, act as storage ―sponges‖ for positively charged heavy metals,
which can be absorbed and adsorbed in muds. Offshore muds are being deposited daily
across the coastlines worldwide, acting as toxic supply to the marine environment. This is
affecting the ecosystem due the suddenly significant concentrations of toxic and
carcinogenic compounds, leading to adverse health effects to all the coastline
communities. Whereas people whose diet is heavily focused on seafood are the most
affected, epidemiological studies conducted are showing evidence that water sources and
agriculture are affected by the sudden increase in the heavy metal concentration, leading
to detrimental health effects (Haroun, 2009).
Most of the presence of heavy metals present in the offshore muds is due to
unregulated industrial discharges and lack of environmental proactive technology. For
example, as pointed out by Haroun (2009), in the Arabian-Persian Gulf area there is a
3

very heavy oil/gas traffic, which contributes heavily to both organic and inorganic
contaminations. The increasing health concerns are due to both the industrial toxic and
carcinogenic heavy metals. Complex combinations of heavy metals, e.g., strontium plus
chromium, leads to bone cancer among other diseases.

4

1.2 Electrokinetics

The theoretical development of electrokinetic phenomena and electrochemical transport
has been studied historically as far back as 1879 by Helmholtz that led to the introduction
of the first analytical equation. Helmholtz described the motion of the charged ionic
solution from the anode to the cathode and explained it by the presence of a double layer.
This double-layer theory is illustrated in Figure 1-1, where the negatively-charged surface
of the clays attracts the positive ions of aqueous medium, forming the immobile double
layer. This immobile double layer is followed by a thick mobile layer with a
predominanance of positively-charged ions (cations), with a few diffused negatively-
charged ions (anions).

Later, the analytical solution was further modified by Smoluchowski in 1921 to
arrive at the Helmholtz-Smoluchowski’s equation (electrokinetic permeability, 𝑘 𝜃 ):

𝑘 𝜃
𝐷

(1-1)
where: D = dielectric constant
= zeta potential
= viscosity of the fluid

5

Figure 1-1: Schematic diagram of electrokinetic double layer (I: Immobile Double Layer,
II: Mobile Double layer, III: Free water, IV: Velocity Profile) as envisioned by Dr. George
V . Chilingar (personal communication). Solid curved line – velocity profile in a capillary.
P = D.C. current power supply. Rock is negatively charged.

6

The proportionality constant, D, has been verified by several investigators for
various types of liquid--solid interfaces. However, extreme sensitivity and complexity of
these phenomena have lead to reports of discrepancies in the relative constancy of this
term. Probstein and Hicks (1993) have shown the effects of concentration of ionic species
within the pore fluid, electric potential, and pH on the zeta potential ( ) . Thus, it doesn’t
remain constant throughout the electrically- induced transport in soils that is governed by
zeta potential.
Counterions from the water solution balance the charges at the solid surface and
form the immobile Stern layer, Figure 1-2. The thickness of the Stern layer is only one or
two molecular diameters consisting of ions that are adsorbed strongly enough to form an
immobile layer. The outer edge of the Stern layer where the ions are mobile is known as
the shear plane. There is a linear potential drop across the width of the Stern layer (ψ
s
–
ψ
ζ
), followed by an exponential potential difference across the diffuse layer between the
shear plane and the bulk solution (ψ
ζ
– ψ
∞
); the bulk solution is designated as the
reference zero potential. The potential difference between the shear plane and the bulk
fluid is known as the zeta potential (Donaldson and Alam, 2008).
The thickness of the Helmholtz layers thus reflects the size of the adsorbed
anions and counter-ions within the Stern layer and is observed by the differences of the
measured linear potential differences within the Stern layer.

7

Figure 1-2: Electric double layer at the interface between a solid and liquid: x
s
= surface
of the solid, x
ζ
= shear plane, x
∞
= bulk liquid, x
ζ
– x
s
= Stern layer, x
∞
– x
ζ
= electrical
diffuse layer. (Debye length). (Modified after Donaldson and Alam, 2008.) Note that
the surface of the solid in this case is positively charged.

8

The length of the exponential electrical field decay (from the shear plane to the
bulk fluid) is known as the Debye length (

). For example, if the plates of a capacitor
have equal charge densities, the zeta potential is the potential difference from the center
of the separation to one of the plates (Donaldson and Alam, 2008):

–

√

(1-2)
(m (mass) =

)
where, ρ
i
is the number density of ions in the solution; Eq. 1-2 also shows that the charge
density of the surface (

) is proportional to the surface potential (

). is the
dielectric constant.

is the permittivity of free space [8.854 * 10
-12
C
2
/ J*m = C
2
/
N*m
2
]. KT is the constant, 4.144 * 10
-21
J at 25
o
C; 4.045 * 10
-21
J at 20
o
C. Z is vertical
distance.
With respect to an ionic solution, the Debye length is the distance from the shear
plane of the Stern layer to the bulk fluid. The Debye length depends on the specific
properties of the ionic solution. For aqueous solutions (Donaldson and Alam, 2008):

𝐵 √𝑀 (1-3)
where B is a constant specific to the type of electrolyte. B is equal to 0.304 for
monovalent cations and anions (NaCl); 0.176 where either the cation or the anion has a
valency of two (CaCl
2
or NaCO
3
); and 0.152 when both ions have a valency equal to two
9

(CaCO
3
). M is the molaritry of the pore solution.
The composition of the Stern layer varies with respect to the nature of the surface
charge and ionic constituents of the electrolyte (Castellan, 1971).
The zeta potential of mineral surfaces in contact with aqueous solutions is a
function of pH. In general, acidic solutions promote positive charges at the surface with
an attendant positive zeta potential and basic solutions produce an excess of negative
charges at the surface from an increase of the hydroxide ion. The pH at which the zeta
potential is equal to zero is defined as the zero point charge (zpc). When the negative and
positive charges of ions in a solution are equally balanced, the solution is electrically
neutral and this condition is defined as the isoelectric point (iep) (Castellan, 1971).
The significance of zeta potential is that its value can be related to the stability of
colloidal dispersions. The zeta potential indicates the degree of repulsion between
adjacent, similarly charged particles in dispersion. For molecules and particles that are
small enough, a high zeta potential will confer stability, i.e., the solution or dispersion
will resist aggregation because the surface charge disperency of the particles are highly
satisfied. When the potential is low, attraction exceeds repulsion and the dispersion will
break and flocculate. Thus, colloids with high zeta potential (negative or positive) are
electrically stabilized, whereas colloids with low zeta potentials tend to coagulate or
flocculate:
Zeta potential is widely used for quantification of the magnitude of the electrical
charge at the double layer. However, zeta potential is not equal to the Stern potential or
electric surface potential in the double layer. Such assumptions of equality should be
10

applied with caution. Nevertheless, zeta potential is often the only available path for
characterization of double-layer properties.
11

Figure 1-3: Schematic representation of zeta potential ( ) (Modified after Zetasizer Nano
series technical note, Malvern Instruments)

12

There is a surface of shear (slipping plane) between the fixed and mobile sub-
regions. The zeta potential ( ) is the potential difference between this plane and the bulk
liquid. This zeta potential ( ) is smaller than the total or thermodynamic potential (after
Butler et al., 1951). The classical zeta potential ( ) equation is as follows (after Street et
al., 1961):

𝐸𝑀 )
𝐷 (1-4)

where, is the viscosity of mass,
EM is the electrophoretic mobility.
D is the dielectric constant.

Anbah (1963) stated that the larger the ionic charge on the clay particle, the
larger the electric potential between the diffuse and inner fixed layer. Thus, fewer ions
are able to move in an external field. Overbeek and Liklema (1969) have shown that the
higher the ion concentration, the smaller the double layer thickness and, hence, the
smaller the zeta potential.
With decreasing pH, however, the zeta potential ( ) decreases until a critical pH
is reached at which time a reversal in the sign of zeta potential occurs (Hunter and James,
1992). This is caused by the accumulation of H
+
ions in low--pH environments, resulting
13

in a compression of the Helmholtz double layer due to the cation build up. As the
concentration of hydrolyzable metal ions increase, the compression of the electric double
layers occurs. This may lead to a reduction in electrokinetic flow in soils with high pore
fluid electrolyte concentrations, making electromigration the dominant mechanism of
electrochemical transport (Pamukcu et al., 2008). This reversal of sign of the zeta
potential ( ) has been found due to the accumulation of cations and the compression of
the electric double layer. The largest effect of zeta potential ) occurs during the
intermediate pH, slightly higher than the value needed for precipitation of the metal
hydroxide. It has been shown to be influenced by the type and concentration of
electrolytes added to the suspension (Kruyt, 1952).
As mentioned earlier, the pH is one of the most important factors affecting the
zeta potential ( ) . Thus, the zeta potential value alone is actually meaningless without
defining the solution conditions (Zetasizer Nano Series Technical Note, Malvern
Instruments, www.nbtc.cornell.edu).
1) On assuming a negative value zeta potential, if acid is added to this suspension,
a point will be reached where the charge will be neutralized. The further addition of acid
will cause a buildup of positive charge. Consequently, the zeta potential ( ) versus pH
curve will be positive at low pH and lower or negative at high pH.
2) On the other hand, if more alkali is added to the system, then the
accumulation and buildup of negative charge on particle will prevail. The point where the
plot of the zeta potential versus pH passes through the zero zeta potential is called the
14

isoelectric point. Usually, a colloidal system is least stable at this point.

15

1.3 Theoretical Analysis

A modern concept of the liquid-solid interface introduced by Gouy (1910) led to the
concept of the diffuse double layer. The solid-liquid interface is the seat of a double layer
in which the ions of one kind are adsorbed and tightly held to the surface, thus leaving an
excess of the other kind of ions in solution. The ions arrange themselves in a diffuse layer
in which the excess of concentration of the second kind over the first dimishes toward the
center of the capillary – from a maximum at the wall to zero at an outer boundary.
Helmholtz (1879) was the first to attack this phenomenon analytically, and
assumed that: (a) the hydrodynamic equations for viscous liquids are valid for the entire
region of the double layer; and (b) laminar flow conditions prevail.
Later modifications by Smoluchowski (1921) led to the famous Helmholtz-
Smoluchowski equations:

𝑣
𝜁 𝐷 𝐸 𝜋
(1-5)

𝑄 𝑒
𝐴 𝜁 𝐷 𝐸 𝜋
(1-6)

where A = the cross-sectional area, D = dielectric constant, = zeta potential, E =
potential difference, and Q
e
= electrokinetic flow rate. Smoluchowski also proved the
16

validity of these equations for porous plugs where A was eliminated by the application of
Ohm's law and by assuming no surface conductance:

(1-7)

𝑄 𝑒
𝐷 𝐸
𝜋
(1-8)

where is the specific conductivity and i is the current through capillaries. It was
proved later that these equations still hold true for turbulent flow (Rutgers, 1957).

If there is surface conductance in the capillaries

AE + SE=I (1-9)

𝑄 𝑒
𝐷 𝜁
𝜋

)
(1-10)

where S = circumference of the capillary and

= specific surface conductance.

17

The necessary corrections, however, could be made by measuring the
conductivity or the resistivity of the liquid while it is present in the capillaries:

𝑄 𝑒
𝐷 𝜁
𝜋

(1-11)

where

is the corrected specific conductivity. Thus, it includes bulk conductivity, ,
and surface conductivity

.

is determined experimentally from the measured
resistance, R, across the core and its cell constant (C):

𝐶
(1-12)

According to Manegold and Solf (1931)

𝐴 )
(1-13)

where, L = length of the core, A = cross-sectional area, ) = volume fraction
available for ionic migration, and = shape factor.

18

𝑄 𝑒
𝐴 𝐷 𝜁 )
𝜋

𝐴 𝐷 𝜁 )
𝜋

𝐸
(1-14)

19

1.4 Transport of Contaminants in Soils on Application of D.C.
Current

If the direction of hydraulic pressure gradient coincides with the direction of DC electric
field current, i.e., Darcy's flow and the electrokinetic transport occur in the same direction,
a one-dimensional mathematical model can be used to show the main mechanisms of the
species' transport. In this case, redistribution of the species concentration in space can be
described as a result of combined influence of three mechanisms: Darcy flow,
electrokinetics and diffusion. The first two relate to the contaminants' solution flow with
respect to the solid soil matrix, whereas the last redistributes the species inside the
flowing fluids (Chilingar et al., 1997).
For the purpose of simplified analysis, it is reasonable to consider a one-
dimensional fluid flow in the direction from anode to cathode. Denoting the distance
from the anode by x and the distance between anode and cathode by 1, one can
consider . The total fluid flow rate

) at the point x can be expressed for
this case in the form:

)

)
𝑒 ) (1-15)

where,

is the hydraulic component of the flow and
𝑒 is electrokinetic component
20

of the total flow

To define

) one can use the Darcy's Law (e.g., Bear, 1973):

) 𝑘

𝑘

(1-16)

where A is the cross-sectional area perpendicular to the direction of fluid flow, 𝑘
is the
Darcy's permeability of porous medium in the direction of flow, is the viscosity of
fluid, and

is the pressure derivative in the direction of flow at point x.
For the electrokinetic flow rate
𝑒 ) one may use the Helmholtz-
Smoluchowski equation version of the following form (Smoluchowski, 1921):

𝑒 ) 𝑘 𝑒

𝑘 𝑒

(1-17)

for which electrokinetic permeability 𝑘 𝑒
is defined by

𝑘 𝑒
)

(1-18)
21

where F is the formation factor, D is the dielectric constant, is the zeta-potential, is
the potential of electric field, and

is the potential derivative in the direction of
flow at the point x.
Chilingar et al. (1968) conducted a simple analysis of conditions that are
responsible for relationship between hydrodynamic and electrokinetic components of the
flow. Based on Eqs. 1-16 and 1-17, they presented the ratio:

(1-19)

This ratio shows that an increase in the electrokinetic flow rate is proportional to
the zeta-potential, dielectric constant, and potential gradient (Chilingar et al., 1997).
The direct conclusion from the Eq. 1-19 is that the electrokinetic technique is
especially effective in cases when hydraulic permeability k
h
is very small, which is valid,
for example, for clays or clayey sands. Electrokinetic flow rate increases with increasing
clay content in sands. For sands it is possible to raise the hydrodynamic component of the
total flow by injection of special purging solutions (Shapiro and Probstein, 1993).
Electrical field application in situ, as a rule, leads to an increase in temperature.
In turn, the temperature increase reduces the viscosity of hydrocarbon-containing fluids
that, according to Eqs. 1-16 and 1-17 would result in an increase of the total flow rate
22

(Chilingar et al., 1968). Analyzing the results of ―in situ‖ trials and verifying
corresponding mathematical models, one should keep in mind this additional positive
side- effect to avoid possible misinterpretations of electrokinetic efficiency. This effect is
insignificant for the dissolved gaseous hydrocarbons (like butane and methane). For
crude oils (e.g., California crude oils), however, the viscosity can be reduced more than
twenty times upon heating from 50 to 100
o
C (Ungerer et al., 1990). This (at least in
theory) would increase the total fluids flow twenty times. Discussing an electrical field
application for the acceleration of fluids transport in situ, one needs to consider also
electr1cal propert1es of soils (electrical resistivity, for example) and ionization rate of the
flowing fluids that can considerably affect the total flow rate. In addition, Chilingar and
his associates (Chilingar et al., 1970) discovered that application of D.C. field to some
soils leads to an increase of their hydraulic permeability that, in turn, can considerably
accelerate the fluids transport. In addition, some clays are destroyed (become amorphous)
upon application of direct electric current, possibly as a result of driving the interlayer
water out (do not swell any longer).

23

1.5 Multicomponent Cleanup Technologies and Examples of
Their Application in situ

There is a wide variety of mechanical, physical, chemical, and bioremediation cleaning
methods that are applied in contemporary practice for the restoration of contaminated site.
It is even difficult to name all of them and give their characteristics. Good classification
of the bioremediation methods with general recommendations of their applications was
presented by Pollard et al. (1994).
For any particular contaminated site, one should select the most appropriate
cleanup technology (or the most appropriate combination of different technologies). The
choice of a concrete technology (or technologies) depends on many factors, e.g., the site
size, type of predominant contamination, the site's future use, and available resources
(time and money). Examples of such an approach to the selection of cleanup strategy
were presented by Blacker and Goodman (1994) and Fairless (1990). They developed
some reasonable selection methodology of cleaning technologies, based on the principles
of system analysis: from the final goal, through the quantitative characterization of the
problem, to the choice of preferable alternatives.
Many good examples of successful application of the combined technologies
were presented by W. Loo and his associates. Loo (1994) used a combined system,
24

including primarily passive cometabolic biotreatment and electrokinetic transport of
amendments and contaminants in solution for degradation of gasoline and diesel in the
soil and groundwater. In one case, spills of gasoline and diesel from an underground
storage tank caused soil and groundwater contamination in the clayey Bay Mud, City of
Hayward, California. The soil contamination extended to a depth of about 10 ft with a
total petroleum hydrocarbons (TPH) concentration of 100 to 3,900 ppm. The gasoline and
diesel in the soil were degraded to less than 100 ppm of TPH, and to less than 10 ppm in
groundwater. The remediation process was completed in four weeks.
A combination of biodegradation and electrokinetic transport with a hot air
venting system and ultraviolet light biocontrol system was used by Loo et al. (1994) for
degradation of gasoline in the clayey soil. The gasoline soil plume covered an area of
about 2,400 sq. ft, to a depth of about 30 ft. The upper 15 ft of sediments were composed
of highly-conductive marine clay, whereas the lower 15 ft consisted of well-cemented
conglomeratic sandstone. The gasoline concentration ranged from 100 to 2,200 ppm. The
process of remediation was completed after about 90 days of treatment. The
concentration of gasoline in the soil after treatment was far below the proposed cleanup
level of 100 ppm. The cost of treatment was about $50 per ton of soil for this advanced
soil treatment process, which provided a cost effective remediation with minimum
disruption to business operations at the site (Chilingar et al., 1997).
A closed recovery system for soil and groundwater for a site contaminated with
gasoline in Greenville, North Carolina, was developed by Burnett and Loo (1994). The
25

dissolved contaminant plume covered an area of 18,000 sq ft and penetrated to the depth
of about 15 ft. The total volume of spill was estimated at 300,000 gallons. The initial
concentration of gasoline in the plume averaged about 40 mg/l of total BTEX (Benzene,
Toluene, Ethylbenzene, and Xylenes).
Special enhanced bioremediation system was designed to clean this site. The
system consisted of two groundwater recovery wells, a treatment unit and an infiltration
gallery. The treatment unit consisted of transfer pumps, pressure filters, granulated
activated carbon filters, air sprayers, holding tanks, chemical feed system, water heater
and monitoring means. The bioenhancement process included heating, addition of
nutrient amendments (monoammonium phosphate and trisodium phosphate), and oxygen
addition (dilute hydrogen peroxide). In six months of operations, BTEX in the plume had
been reduced to a level less than 6.5 mg/l with the passage of 11 pore volumes of
displacement.

26

1.6 Dewatering of Soils

Electrokinetics has long been applied in soil engineering. Several patents on the removal
of water from clayey and silty soils by electrokinetic were issued in Germany before
World War II. Later, the method was widely and successfully used in Germany, England,
the U.S.S.R., and Canada in drying water-logged soils for heavy construction. The
development of these practical applications has been largely due to the work of
Casagrande (1937-1960) who has carried on a continuous research on their feasibility in
relation to various soil characteristics.
The literature of civil engineering, soil mechanics, and highway research has
reported investigations made by Winterkorn (1947-1958), Casagrande (1937-1960), and
others on the nature and scope of the electrical treatment of soils.
Some examples of electrokinetics treatment in civil engineering are described
here for the purpose of illustration.

27

1.6.1 Field Applications of Electrokinetics

Railway cut, Salzgitter, Germany (Casagrande, 1947). Difficulties which arose during the
construction of a double-track railway cutting, in a loose-loam deposit due to the flow of
soft soil, were overcome by a large-scale drying operation using electrokinetic. In
sections of 100 meters, well electrodes 7.5 meters deep and 10 meters apart were used.
Before the application of electrical potential, the average rate of flow of water was 0.4
cu.m. / day /20 wells. An electrical potential, with an average tension of 180 volts and
average current of 19 amps/well, was applied. During an eight-week period, the flow
continued at an almost constant rate of 60 cu.m./day/20 wells, i.e., at 150 times the flow
rate before the application of potential.
U-boat pen, Trondheim, Norway. Several attempts to make an excavation about
14 meters deep in a very thick stratum of clayey silt interspersed by seams of sand in the
proximity of the sea were doomed to failure because of the very active uplift
phenomenon. The application of electrokinetics to cause water to flow away from the
excavation site was next tried. The salt deposits, which increased the electrical
conductivity of the soil, required high consumption of current.
Before the application of electrical potential, the flow rate varied from one to 50
liters per hour per well. A current of 26 amps at 40 volts tension was used. The
application of current increased the flow rate up to 11-479 liters per hour per well. The
average power consumed was estimated to be 0.4 Kw-hr per cubic meter of soil
28

excavated.
Lime sludge deposits. Some tests were made by Casagrande also on dewatering
lime-sludge deposits (Wulprath, Germany) having a uniform water content of 120 per
cent of dry weight. A 25 per cent decrease in moisture content was obtained by the
application of electrical potential with 70-volt tension and a current of 50 amps for 14
days. The reduction lines of water content indicated that the electrokinetics dewatering
process took place uniformly along the lines of equal potential strength.

29

1.7 Electrochemical Treatment of Soil and Weak Rocks

The first work along this line was carried out by Casagrande (1930) who noticed that a
permanent stabilization of soil could be obtained by using aluminum electrodes. These
aluminum electrodes were found to be greatly corroded and aluminum compound
deposits were noticed around the electrodes. Encouraged by the model tests, Casagrande
(1937) undertook a full scale experiment and came to the conclusion that electrochemical
treatment could be used also for increasing the bearing capacity of piles.
A reduction in water saturation around the borehole (invaded zone by filtrate)
may be accomplished by means of electrokinetics, thus increasing the relative oil
permeability. This can be done over a very short period of time, and in the future may
prove to be one of the most economical means of borehole treatment, particularly in the
case of dirty formations.
Selective ion-drive. In many cases, whether during water flooding or primary
production, it is desirable to add some surface-active agents in order to influence or
change the surface-liquid properties. Usually this is accomplished by adding chemical to
the injection fluid in the case of secondary recovery or by adding these chemicals through
the producing well by means of back-flowing for specific zone treatment (Anbah et al.,
1965).
The electrokinetics effect (ionic transport) can be used as an excellent ion-drive
mechanism. Various kinds of ions can be driven selectively into the zones of interest by
30

the application of direct electric current for purposes of treatment. For example, in the
case where the formation is desired to be oil-wet rather than water-wet in a specific zone,
chemical additives such as ionizable organic amino-compounds may be driven into that
particular zone by playing with the electrode arrangement. A simplified sketch of
possible electrode arrangements is shown in Figure 1-4, where the wet ground is used as
one of the terminals.
Generally speaking, however, it is always preferable to use old pipes or rods of
any conducting material as anodes, which are inserted in the wet ground at a shallow
depth around the treated well (Anbah et al., 1965). Inasmuch as the anodes will usually
corrode, these rods or pipes can be replaced very easily in due time. In the cases where
the anodes are lowered in the well to face the producing zone, it will be advisable to use
nonelectrolyzable electrode material such as carbon, graphite, or noble metals. The initial
cost for the noble metal electrodes may be decreased by using them as platings over base
materials. In case it is feared that the casing or tubing of the injection well may corrode,
an electrical potential can be superimposed on them in such a way that they will be
cathodically protected. No such precautions are necessary in the case of the producing
wells because the cathodes as a whole will be protected against corrosion.

31

Figure 1-4: Electrode arrangement for selective ion-drive. Conducting pipes driven into
the wet ground are used as anodes or cathodes. (After Anbah et al., 1965.)\

32

1.8 EEOR (Electrical Enhanced Oil Recovery)

In 1952, Tchilingarian suggested the possibility of using direct electric current for
separation of fine sediments into grades on the basis of different cataphoretic velocity
exhibited by clay particles of different size. This was achieved on treatment of clays with
NaOH, because OH
-
ions impart greater negative change to clays and, consequently,
greater velocity towards the positive electrode. He started this research because he was
questioning the statement in textbooks that ―cataphoretic velocity is independent of size
and shape of colloids‖ (personal communication with Professor G.V. Chilingar, 2010).
Also, knowing the success in dewatering of clays by soil engineers, he started
research on EEOR together with his students at the Petroleum Engineering Laboratories
of the University of Southern California (e.g., Anbah, 1963).
G. V. Chilingar and his students at the University of Southern California (Ace,
1955; Amba et al., 1964, 1965; Chilingar et al., 1968a,b, 1970,1997) conducted numerous
laboratory tests involving electrokinetics, which indicated that this low-power drain
mechanism could be used for EOR. Tikhomolova (1993) described similar studies
conducted at the University of St. Petersburg, also suggesting electrokinetics as a
potential EOR technology. Hill et al. (1997) conducted bench-scale studies, which
suggested that hydrocarbons could be transported via electrokinetic mechanisms.
Pamukcu et al. (1995) and her students at Lehigh University, demonstrated electrokinetic
transport of hydrocarbons (PAH), in clay-rich soils, as a method of remediating
manufactured gas plant site contamination.
33

Upon application of DC current, the mobile Gouy layer migrates toward the
(negative) cathode. This motion of the water molecules and cations within the Gouy layer
drags the water molecules, cations, and anions, in the free fluid, as well as any non-
wetting fluid, along with it (Hill et al., 1997). Extensive experimental work, conducted at
The University of Southern California (Ace, 1955; Amba et. al., 1964, 1965; Chilingar et
al., 1968a,b, 1970, 1997) showed up to six-fold volumetric fluid flow increases in cores
containing clay minerals, compared to only 2-fold increases in pure silica cores (see
Figure 1-5). Chilingar et al. (1970) speculated that in pure silica core fluid flow might be,
at least partly, due to a thermal effect. Mitchell (1993) maintained that all silicate
minerals show this increased flow effect, to some extent. Those with high cation
exchange capacity (CEC) exhibit the greatest flow increases.
Electro-enhanced oil recovery (EEOR) is an emerging technology that could
significantly improve oil recovery, at costs below other secondary and tertiary oil
recovery technologies, in environments where other technologies either do not work or
are not attractive. EEOR has a nonexistent water demand, a smaller carbon footprint than
traditional EOR technologies, such as steam injection, and does not involve injection of
hazardous liquids, as is the case for caustic and/or co-solvent flood. EEOR requires
minimal surface facilities. No steam generators, compressors, surface working fluid
pumps, and/or hazardous material storage tanks are required. EEOR involves passing
direct current (DC) electricity between cathodes (negative electrodes) in the producing
reservoir and anodes (positive electrodes) either at the surface and/or at depth. The use of
DC electrical power as an EEOR process was originally proposed by Prof. George V.
34

Chilingar in 1955 and then developed and patented by General Electric (GE) (Bell and
Titus, 1973, 1974). It is currently being developed by Electro Petroleum, Inc., (EPI) of
Wayne, Pennsylvania, USA (Bell et al., 1985; Titus et al., 1985; Wittle and Bell, 2005a,
2005b). These two organizations, collectively, spent several years and millions of (US)
dollars in R&D to overcome encountered field operational difficulties. Their combined
efforts resulted in successful EEOR demonstrations at California and Alberta heavy
oilfields. At the time of the original GE EEOR Joule heating research and development
(R&D), Professor G. V. Chilingar, and his students at the University of Southern
California (Ace, 1955; Amba et al., 1964, 1965; Anbah et al., 1965; Chilingar et al.,
1968a,b, 1970), had been conducting laboratory research, which indicated that DC
current could increase effective reservoir permeability and hydrocarbon recovery, via
electrokinetic processes.
Successful EEOR field tests have been achieved lately (Wittle et al., 2008 and
2011) in California and Canada. Application of EEOR would return about 25 dollars per
each dollar invested, considering the initial installation cost and that of electricity. Anbah
et al. (1965) suggested a few electrode arrangements for waterflooding operations.

35

Figure 1-5: Relationship between potential gradient and normalized electrokinetically
induced fluid flow, for different silica--clay mineral mixtures. Core No. 1: 94% silica
sand and 6% montmorillonite clay. Core No. 2: 94% silica sand and 6% illite clay. Core
No. 3: 94% silica sand and 6% kaolinite clay. Core No. 4: 100% 200-mesh silica sand.
High cation-exchange capacity clays (montmorillonite and illite) exhibit greater
sensitivity to DC electrical current stimulation. (After Chilingar et al., 1970.)

36

1.9 Economic Feasibility

Many assumptions should be' made in order to make rough calculation of economic
feasibility of using D.C. current. The variables which will affect the economic
considerations include: (1) thickness, depth, and resistivity of the pay zone, (2)
arrangement of the electrodes, (3) duration of the electrical treatment, (4) labor cost, and
(5) price of electricity at the site of application.
In general, the rock resistivity is a function of the amount of interstitial water
present. This in turn is determined by the rock porosity and the amount of the pore space
that is filled by interstitial water. The flow of electrical current in such a case is not a
simple linear flow but follows an irregular path around the individual sand grains. This
flow pattern will increase the length of the current flow lines and the resistivity of the
rock. Inasmuch as the current is mainly transmitted through the rock in the form of
electrolytic conduction, the resistivity of the interstitial formation water seems to be the
deciding factor in the formation resistivity as a whole. The presence of clay, however,
greatly affects the electrical resistivity of the formation, specially in the case of fresh
formation water (Anbah et al., 1965).
Although the electrokinetics depends mainly on the imposed electrical potential
gradient, yet the associated electrical current is conditioned by the type of formation
under consideration and its electrolytic content. There is no simple relation between the
amount of liquid transported by electrokinetics and the quantity of electricity consumed.
The presence of expandable colloidal matter in a microporous media further complicates
37

the picture.
In field application, the energy consumption will depend on the dimensions of
the electrodes, the applied electrical potential, and the underground condition. If these
factors are known, the amount of transmitted electrical current can be estimated. Upon
switching the current on, it will drop gradually because the over-all resistance will
increase.
The total amount of current transmitted (I) for various electrode arrangement can
be estimated (Rudenberg, 1945; Casagrande, 1949) by using equations such as those
presented below:
(a) For two cylindrical electrodes of equal length and cross- sectional area:

𝐸

(1-20)

where is the formation resistivity in ohm-meters; L and r are the length and radius of
the electrode in meters, E is the imposed electrical potential in volts; and d is the distance
between the anode and the cathode in meters.
(b) For two cylindrical electrodes with different radii:

𝐸
(

) (1-21)

38

(c) For a row of alternate anodes and cathodes the amount of electrical current can be
given approximately by

𝐸
(

) (1-22)

where N is the number of electrodes in each group.

(d) For spherical flow of current from a sphere with radius a to a distance x in the ground,

𝐸
(

) (1-23)

and when x approaches infinity,

goes to zero and

𝐸
(1-24)
Before one can proceed with estimating the consumption of power, some
assumptions have to be made. The following estimation of the current application,
39

because it is very difficult to estimate the decrease in the current flow as a result of the
increase in the overall resistance. On assuming that (1) the electrical current is available
at the electrode; (2) the formation resistivity is constant and is equal to 10 ohm-meters; (3)
the electrode-length and radius are equal to three and 0.1 meters, respectively; (4) the
applied potential is equal to 100 volts, and (5) the distance between electrodes is equal to
40 meters (Anbah et al., 1965) and substituting the above values in Eq. 1-21:

Thus, the power consumption is then equal to

The approximate cost of electricity (at $0.059/Kw.-hr.) = 3.14 x 24 x 0.059 =
$ 4.45 per day per well. If the labor cost is assumed to be $50 per day per well, then the
total cost becomes $230.76 per well per day (See Handbook of Construction Cost,
Halbert Powers Gillette, 2006.). It is assumed that the equipment needed (electronic
power supply, electrodes, power cables, etc.) will cost approximately $55,000 per well. If
the estimated life of the equipment is five years and its salvage value is 11,000, then by
using straight-line depreciation at 6 per cent average interest, the annual depreciation plus
interest is equal to $10,494 per well (Modified after Anbah et al. 1965).
According to laboratory experimental results and the application of electrokinetics
in related engineering field, an average increase in the electrokinetics flow rate of water
(corresponding to 3.14 KW-hr.) can be estimated as 0.75 cc./sec. or 41.7 B/D. If it is
further assumed that a piston like displacement of water to oil (banking) takes places, an
40

average increase in the oil produced is estimated to be 13.9 B/D per well. The annual
gross dollar return (at $70/Bbl) is equal to $355,145.00, and after CMR tax (at $6/Bbl) is
equal to $324,704.00. This value minus the annual labor and electricity cost will give the
net annual profit of: $324,704.00 - $84,227.40 = $240,476.60. The net profit is
approximately equal to 240,476.60/10,494.00 ≈ $22.92 dollar returned per dollar invested
(modified after Anbah et al., 1965).
These sample calculations are presented here in order to indicate the possibility of
such application in the field. It should be kept in mind, however, that for field application
the current is best applied in an interruptive manner which will cause a considerable
saving in power consumption. For the purpose of well stimulation, the application of
current may not exceed a period of one to two weeks. It is believed that such short
electrical treatment may lead to 50 or even 100 per cent increase in the average flow rate
of oil and water
The economic feasibility of using this technique in oil production will be more
apparent in a large-scale field application. In order to ensure optimum results, it is
strongly recommended that such large-scale application should be preceded by a flood
pot test followed by a pilot test (Anbah et al., 1965).

41

Chapter 2

Apparatus

As an introduction, it is important to show the equipment initially used in the Petroleum
Engineering Department of the University of Southern California (Figures 2-1 and 2-2)
The equipment used by Dr. S. Pamukcu (Figures 2-3 and 2-4 ) and Dr. .M. Haroun
(Figure 2-5) are also presented here. Figure 2-6 shows the equipment used by the writer.

42

Figure 2-1: A schematic diagram showing the first apparatus and connections used in
Petroleum Engineering Laboratories at the University of Southern California. (Personal
communication with Dr. George V . Chilingar.)
43

Figure 2-2: Schematic diagram of second apparatus and connections used in
Petroleum Engineering Laboratories at the University of Southern California.
(Personal communication with Dr. George V . Chilingar.)

44

Figure 2-3: Electrokinetic apparatus, DC power source and graduated glass
burettes to measure both inflow and outflow at each of the two electrode ends
(anode and cathode). Apparatus used by Dr. S. Pamukcu at Lehigh University.

45

Figure 2-4: Schematic diagram of glass elektrokinetic cell. (After Pamukcu et al.,
1993.)

46

Figure 2-5: Photograph of electrokinetic apparatus and multimeter for measuring voltage,
current and resistance used by Dr. M. Haroun.
47

Figure 2-6: Apparatus used in electroremediation of heavy metals from offshore muds
and sediments with partial chlorine gas removal equipment (controlling valve at left gas
tank). Apparatus used by the writer.
48

2.1 Sampling Area in Abu Dhabi, U.A.E.

Samples were collected at three different locations: First Sample was collected near the
refinery/ industrial area and bridge as shown in Figure 2-7, which was marked as 24
o

25’27‖ North, 54
o
29’ 30‖ East, Altitude 0 m. Second sample location is shown Figure 2-
8; located near sewer -- 24
o
27’14‖ North, 54
o
24’ 19‖ East, Altitude 0 m. Sampling area
near the port was selected as the third location (Figure 2-9); however, the size distribution
of this sample was of sand size. All collected samples were sieved with 1-mm sieve for
the removal of shells and other coarse materials before testing. All samples were
collected by the writer.
49

Figure 2-7: Sample location No. 1 near the refinery industrial area. (24
o
25’27‖ North, 54

o
29’ 30‖ East, Altitude 0 m)
50

Figure 2-8: Sample No. 2 location near the sewer outlet. (24
o
27’14‖ North, 54
o
24’ 19‖
East, Altitude 0 m)
51

Figure 2-9: Sampling area near the port (Sample No.3) in Abu Dhabi, U.A.E. (24
o

22’17‖ North, 54
o
28’ 2‖ East, Altitude 0 m)
52

2.2 Particle Size Distributions of Samples

The samples were sieved using the following procedures: ISO 3310-1:2000 (wet sieving)
and BS ISO 11277:2009 (dry sieving). The water contents of samples were measured
according to ASTM D2215-06. According to USDA, sediment size distribution was
determined using the following classification: very coarse sand, coarse sand, medium
sand, fine sand, very fine sand, silt and clay (See Table 2-I). Figure 2-10 shows the
texture triangle proposed by USDA. Sieve analyses of samples are presented in Figs. 2-11
and 2-12.

53

Table 2-1: Sediment classification according to USDA sediment textural system
(Modified)

Sediment Diameter limits (mm)
(USDA Classification)
very coarse sand 2.00 ~ 1.00
coarse sand 1.00 ~ 0.50
medium sand 0.50 ~ 0.25
fine sand 0.25 ~ 0.10
very fine sand 0.10 ~ 0.05
silt 0.05 ~ 0.002
clay < 0.002

54

Figure 2-10: Sediment (soil) texture triangle (USDA).

55

Table 2-2: Particle size distribution of sample collected in Area No.1.

Opening (mm) Sediment (g) Cumulative Wt. (%)
2 1.72
0.688
0.5 10.26
4.792
0.25 28.65
16.252
0.125 66.72
49.94
0.063 105.23
85.032
Less < 0.063 37.42
100
- 250 -

Table 2-3: Particle size distribution of sample collected in Area No.2.

Opening (mm) Sediment (g) Cumulative Wt. (%)
2 2.2
0.215572
0.5 55.27
5.631332
0.25 86.22
14.0798
0.125 287.1
42.21197
0.063 438.11
85.1412
Less < 0.063 151.64
100
- 1020.54 -
56

Figure 2-11: Particle size distribution curve of sample collected in Area No.1.

57

Figure 2-12: Particle size distribution of sample collected in Area No.2.
58

2.3 Preparation of Samples

The whole samples were consolidated for seven days at 30 psi pressure (Figure 2-13).
The pressure was gradually increased until reaching 30 psi. After completion of tests, the
EPA 3050b method was used to extract the heavy metals. Then, concentrations of metals
were measured using ICP-MS equipment.
The diameter of the core pipe (P.V .C.) was 3.75 cm (1.5 inch). The length was 10
cm, 20 cm, and 30 cm. Silicon, teflon tape and rubber O-rings were used for connecting
the sample chamber of consolidated sample to the anode chamber and cathode chamber.
The volumes of cathode and anode chambers were 1000 ml each. Cathode and
anode chambers are at the same elevation.
Carborandum porous stones, which were installed in the end of the sample, had a
permeability of 10
-3
cm/sec. They are highly porous compared to the muds tested, which
have hydraulic permeability ranging from 10
-6
to 10
-8
cm/sec (Haroun, 2009). The porous
stones were cleaned with diluted strong acid such as hydrochloric acid, sulfuric acid, or
nitric acid and then placed in the boiling de-ionized water before using them.
The diameter and length of electrodes, which were composed of graphite, was
0.635 cm and 12 cm. Total surface area calculated was 24.56 cm
2
; however, the surface
area reacted was approximately 20.56 cm
2
as 10 cm which is reached with the solution at
each chamber.
Fluid connections: Teflon or stainless steel quick-connections were provided on
the bottom of the back wall of the electrode chambers. These outlet or inlets are then
59

connected to volume measuring tubes and pumped via Teflon tubing. The advantage of
the quick connections is that they close the connection upon detachment, which allows
the electrokinetic (EK) cell to be detached from the control panel while the electrode
chambers are still being charged with fluid.
Gas expulsion or sample extraction/injection ports: These ports are pressure
valves provided on the cover plate over each electrode chamber. These valves have metal
surfaces which are coated to control any deterioration by electrochemical reactions or
metal ion deposition on them. Sample extractions or fluid injections are accomplished
using a volumetric syringe which allows for accurate control of quantities of fluids.
Power supply: Variable direct current (DC) power supply was used capable of
applying either constant voltage (0 to 105 volts), or constant current (0 to 2500 mA).
These units also contain analog meters for measuring voltage and current.
Compaction Apparatus: A schematic diagram of the compaction apparatus used is
shown in Fig. 2-13. The apparatus consists of a PVC sample cell (guide tube) measuring
45.72 cm in length by 2.67 cm in diameter, in to which the slurry sample is injected. The
weight base with compacting column causes a piston - like displacement based on choice
of several weights that allow for a varied pressure range of 5 psi to 30 psi. This is then
placed on top of the injected slurry that’s contained within the PVC sample cell with the
porous stone placed at the bottom end. The weights are placed in the tray at the top of the
compacting column in progressive increments, throughout a period of 24 hours reaching
to a final pressure of 30 psi. During compaction, fluid is drained at the top and bottom of
the sample via porous stones resting on both ends of the core.
60

Muds are prepared by mixing an aqueous solution of the desired contaminant with
the mud. After the 24-hour period of compaction, all the samples had a water content of
40% recorded as the initial water content before the E-K test.
Electrokinetics Testing: In all experiments, a constant 20-volts DC potential was
applied across the core samples. The current density was recorded. This is done using a
multi-meter to read voltage across the E-K apparatus via power connections to each of
the primary electrodes and on the secondary electrodes along the sample tube. Readings
were taken at 0, 15 and 30 minutes and one and two hours after the start of the test
(Pamukcu et al., 1993). During cell disassembly, the pH of the anode and cathode fluid
was recorded and a sample was taken for analysis. Finally the mud was extruded from the
core sample and measurements were made at 5 evenly spaced points along the length of
core for pH, water content and redox-potential in volts (Pamukcu et al., 1993).
61

Figure 2-13: The consolidation equipment setup used to prepare samples.

62

Figure 2-14: Sampling locations

63

Chapter 3

Experiment Results

In order to determine the optimum voltage gradient required in electroremediation of
various heavy metals, the following experiments were performed.
64

3.1Removal of Heavy Metals upon Application of D.C. Current
Using Different Voltage Gradients for the Following Metals: Al:
Aluminum, As: Arsenic, Cs: Cesium, Cr: Chromium, Se:
Selenium, Pb: Lead and Zn: Zinc.

65

Figure 3-1: Concentration of Al upon EK treatment. – Length: 10 cm, 10 Vol., Treatment
time: 24 hours.
66

Figure 3-2: Concentration of Al upon EK treatment. – Length: 10 cm, 20 Vol., Treatment
time: 24 hours.
67

Figure 3-3: Concentration of Al upon EK treatment. – Length: 10 cm, 30 Vol., Treatment
time: 24 hours.
68

Figure 3-4: Concentration of As upon EK treatment. – Length: 10 cm, 10 Vol., Treatment
time: 24 hours.
69

Figure 3-5: Concentration of As upon EK treatment. – Length: 10 cm, 20 Vol., Treatment
time: 24 hours.
70

Figure 3-6: Concentration of As upon EK treatment. – Length: 10 cm, 30 Vol., Treatment
time: 24 hours.
71

Figure 3-7: Concentration of Cs upon EK treatment. – Length: 10 cm, 10 Vol., Treatment
time: 24 hours.
72

Figure 3-8: Concentration of Cs upon EK treatment. – Length: 10 cm, 20 Vol., Treatment
time: 24 hours.
73

Figure 3-9: Concentration of Cs upon EK treatment. – Length: 10 cm, 30 Vol., Treatment
time: 24 hours.
74

Figure 3-10: Concentration of Cr upon EK treatment – Length: 10 cm, 10 V ol., Treatment
time: 24 hours.
75

Figure 3-11: Concentration of Cr upon EK treatment – Length: 10 cm, 20 V ol., Treatment
time: 24 hours.
76

Figure 3-12: Concentration of Cr upon EK treatment.– Length: 10 cm, 30 V ol., Treatment
time: 24 hours.
77

Figure 3-13: Concentration of Se upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours.
78

Figure 3-14: Concentration of Se upon EK treatment.– Length: 10 cm, 20 V ol., Treatment
time: 24 hours.
79

Figure 3-15: Concentration of Se upon EK treatment.– Length: 10 cm, 30 V ol., Treatment
time: 24 hours.
80

Figure 3-16: Concentration of Pb upon EK treatment.– Length: 10 cm, 10 V ol., Treatment
time: 24 hours.
81

Figure 3-17: Concentration of Pb upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours.
82

Figure 3-18: Concentration of Pb upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours.
83

Figure 3-19: Concentration of Zn upon EK treatment. – Length: 10 cm, 10 V ol.,
Treatment time: 24 hours.

84

Figure 3-20: Concentration of Zn upon EK treatment. – Length: 10 cm, 20 V ol.,
Treatment time: 24 hours.

85

Figure 3-21: Concentration of Zn upon EK treatment. – Length: 10 cm, 30 V ol.,
Treatment time: 24 hours.

86

Figure 3-22: Concentration of Al upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours.
87

Figure 3-23: Concentration of Al upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours.
88

Figure 3-24: Concentration of Al upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours.
89

Figure 3-25: Concentration of As upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours.
90

Figure 3-26: Concentration of As upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours.
91

Figure 3-27: Concentration of As upon EK treatment.– Length: 20 cm, 60 V ol., Treatment
time: 24 hours.
92

Figure 3-28: Concentration of Cr upon EK treatment.– Length: 20 cm, 20 V ol., Treatment
time: 24 hours.
93

Figure 3-29: Concentration of Cr upon EK treatment.– Length: 20 cm, 40 V ol., Treatment
time: 24 hours.
94

Figure 3-30: Concentration of Cr upon EK treatment.– Length: 20 cm, 60 V ol., Treatment
time: 24 hours.
95

Figure 3-31: Concentration of Cs upon EK treatment.– Length: 20 cm, 20 V ol., Treatment
time: 24 hours.
96

Figure 3-32: Concentration of Cs upon EK treatment.– Length: 20 cm, 40 V ol., Treatment
time: 24 hours.
97

Figure 3-33: Concentration of Cs upon EK treatment.– Length: 20 cm, 60 V ol., Treatment
time: 24 hours.

98

Figure 3-34: Concentration of Se upon EK treatment.– Length: 20 cm, 20 V ol., Treatment
time: 24 hours.
99

Figure 3-35: Concentration of Se upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours.
100

Figure 3-36: Concentration of Se upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours.

101

Figure 3-37: Concentration of Pb upon EK treatment.– Length: 20 cm, 20 V ol., Treatment
time: 24 hours.

102

Figure 3-38: Concentration of Pb upon EK treatment. – Length: 20 cm, 40 V ol.,
Treatment time: 24 hours.

103

Figure 3-39: Concentration of Pb upon EK treatment. – Length: 20 cm, 60 V ol.,
Treatment time: 24 hours

104

.

Figure 3-40: Concentration of Zn upon EK treatment. – Length: 20 cm, 20 V ol.,
Treatment time: 24 hours.
105

Figure 3-41: Concentration of Zn upon EK treatment.– Length: 20 cm, 40 V ol., Treatment
time: 24 hours.

106

Figure 3-42: Concentration of Zn upon EK treatment.– Length: 20 cm, 60 V ol., Treatment
time: 24 hours.

107

Figure 3-43: Concentration of Al upon EK treatment.– Length: 30 cm, 30 V ol., Treatment
time: 24 hours.

108

Figure 3-44: Concentration of Al upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours.

109

Figure 3-45: Concentration of Al upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours.

110

Figure 3-46: Concentration of As upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours.

111

Figure 3-47: Concentration of As upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours.
112

Figure 3-48: Concentration of As upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours.

113

Figure 3-49: Concentration of Cr upon EK treatment. – Length: 30 cm, 30 V ol.,
Treatment time: 24 hours.
114

Figure 3-50: Concentration of Cr upon EK treatment. – Length: 30 cm, 60 V ol.,
Treatment time: 24 hours.
115

Figure 3-51: Concentration of Cr upon EK treatment. – Length: 30 cm, 90 V ol.,
Treatment time: 24 hours.
116

Figure 3-52: Concentration of Cs upon EK treatment.– Length: 30 cm, 30 V ol., Treatment
time: 24 hours.
117

Figure 3-53: Concentration of Cs upon EK treatment.– Length: 30 cm, 60 V ol., Treatment
time: 24 hours.
118

Figure 3-54: Concentration of Cs upon EK treatment.– Length: 30 cm, 90 V ol., Treatment
time: 24 hours.

119

Figure 3-55: Concentration of Se upon EK treatment.– Length: 30 cm, 30 V ol., Treatment
time: 24 hours.

120

Figure 3-56: Concentration of Zn upon EK treatment.– Length: 30 cm, 60 V ol., Treatment
time: 24 hours.

121

Figure 3-57: Concentration of Se upon EK treatment.– Length: 30 cm, 90 V ol., Treatment
time: 24 hours.

122

Figure 3-58: Concentration of Pb upon EK treatment – Length: 30 cm, 30 V ol., Treatment
time: 24 hours.

123

Figure 3-59: Concentration of Pb upon EK treatment.– Length: 30 cm, 60 V ol., Treatment
time: 24 hours.
124

Figure 3-60: Concentration of Pb upon EK treatment.– Length: 30 cm, 90 V ol., Treatment
time: 24 hours.
125

Figure 3-61: Concentration of Zn upon EK treatment.– Length: 30 cm, 30 V ol., Treatment
time: 24 hours.

126

Figure 3-62: Concentration of Zn upon EK treatment.– Length: 30 cm, 60 V ol., Treatment
time: 24 hours.

127

Figure 3-63: Concentration of Zn upon EK treatment.– Length: 30 cm, 90 V ol., Treatment
time: 24 hours.

128

3.2 Comparison of Removal of Heavy Metals after 48 and 72
hours

129

Figure 3-64: Concentration of Al upon EK Treatment after 48hours; length of core = 10
cm.

130

Figure 3-65: Concentration of Al upon EK Treatment after 72hours; length of core = 10
cm.

131

Figure 3-66: Concentration of Cr upon EK Treatment after 48hours; length of core = 10
cm.

132

Figure 3-67: Concentration of Cr upon EK Treatment after 72hours; length of core = 10
cm.

133

Figure 3-68: Concentration of Cs upon EK Treatment after 48hours; length of core = 10
cm.

134

Figure 3-69: Concentration of Cs upon EK Treatment after 72 hours; length of core = 10
cm.

135

Figure 3-70:.Concentration of Se upon EK Treatment after 48 hours; length of core = 10
cm.

136

Figure 3-71: Concentration of Se upon EK Treatment after 72 hours; length of core = 10
cm.

137

Figure 3-72: Concentration of Cr upon EK Treatment after 48 hours; length of core = 20
cm.

138

Figure 3-73: Concentration of Cr upon EK Treatment after 72 hours; length of core = 20
cm.

139

Figure 3-74: Concentration of Cs upon EK Treatment after 48 hours; length of core = 20
cm.

140

Figure 3-75: Concentration of Cs upon EK Treatment after 72 hours; length of core = 20
cm.

141

Figure 3-76: Concentration of Zn upon EK Treatment after 48 hours; length of core = 20
cm.

142

Figure 3-77: Concentration of Zn upon EK Treatment after 72 hours; length of core = 20
cm

143

3.3 Effect of Partial Chlorine Gas Removal

3.3.1 Partial Chlorine Gas Removal

In order to enhance the removal efficiency of heavy metals by management of the in-situ
chlorine gas (Cl
2
) production was successfully attempted. The tests showed a high
removal efficiency of heavy metals at the anode end of cores after 24 hours of EK
application. In the initial tests, high electrokinetic flow potential was achieved; however,
high levels of chlorine gas were produced due to the high-salinity environment. Produced
chlorine gas at the anode is toxic and acidic, causing corrosion of the equipment. The
process was improved by controlling and maintaining a fraction of the chlorine gas (Cl
2
)
in place. An ideal fraction of chlorine gas maintained in the system to enhance the EK
current was identified. In this study, two different fractions of chlorine gas (0, and 100 %)
were used at various concentrations of heavy metals and voltage gradients. The sample
diameter of cores was 3.81 cm (1.5 inch); pH and temperature were measured
continuously.

H
+
was produced at the anode (3-1) and OH
–
at the cathode (3-2).

H
2
O – 2e
-
 ½ O
2
+ 2 H
+
(3-1)
2H
2
O +2 e
-
 H
2
+ 2 OH
-
(3-2)
144

These two equations are fundamental electrode reactions occurring in the electrokinetic
cell.
In this study, the chlorine gas (Cl
2
) was produced at the anode, together with O
2
in
the presence of saline water.

H
2
O – 2e
-
 ½ O
2
+ 2 H
+
(3-1)
2Cl
-
– 2e
-
 Cl
2
(3-3)

The pH was continuously maintained at a value less than 10 at the cathode end,
for increasing the efficiency and preventing the scaling in the cathode chamber. The value
of pH at the anode was not controlled because saline water was flushed through the anode
chamber by a peristaltic pump. The pH in the anode chamber was measured continuously
and remained at less than about 2.5 (Figure 3-78). The chlorine gas (Cl
2
) was treated
using a filtration system before being released to air.
In a closed system, the Cl
2
gas was not allowed to escape with resulting increase
in pressure, whereas in the open system the Cl
2
gas in allowed to escape to the
atmosphere.

145

Figure 3-78: Change in pH at the anode and cathode with EDTA acid application.
(Sample length = 10 cm; V oltage = 11 V; treatment time = 24 hours. Upper curve-- pH at
the cathode. Lower curve -- pH at the anode.)

146

Figure 3-79: Five copper rings were mounted in mud samples.

147

Five copper rings were mounted inside each sample (Figure 3-79) and then
examined for degree of corrosion.
Tests were performed with the following objectives in mind:
1. Reducing the cost of controlling pH by free Cl
2
gas and gas pressure generated at
anode chamber.
2. Controlling pH by keeping a fraction of chlorine gas in-situ. Chlorine gas was
transported from anode to cathode.
3. Improving the efficiency of removal of heavy metals from the contaminated muds

The samples were collected from two different contaminated areas in Abu Dhabi;
(1) offshore muds adjacent to refinery--industrial area, and (2) offshore muds in port area.
Mud samples were sieved using a 1-mm sieve and then compressed in a cylinder
3.81 cm in diameter and 30-cm long for seven days. Applied pressure was 30 psi.
Two samples 30-cm in length were treated continuously with DC current for 24
hours: sample No.1, open system, and sample No.2, closed system. Two other samples
were treated for 40 hours (sample No.3, open system, and sample No. 4, closed system)
with two 8-hour interruptions (total treatment time = 24 hours).
The experimental results presented in Figures 3-80 through 99. Figures 3-82
through 3-91 show the results of 24-hour treatment, whereas Figures 3-94 through 3-99
show the results after EK treatment applied for 40 hours with two 8-hour interruptions
(actual treatment time = 24hours). Water contents were reduced from 35% to 30% with
temperature increase of 20 º C to 45 º C.
148

Figure 3-80 shows the results of application of different voltage gradients in two
tests. Application of potential gradient of 3.5 V/cm in the open system resulted in an
increased removal efficiency when compared to application of 3.5 V/cm. Figure 3 -82
demonstrates that the reduction in aluminum concentration was significantly greater with
the open test. While applying almost 30% less voltage gradient, the electrokinetic
remediation of aluminum proved to be up to 10 times more at the fourth tested location.
Higher removal efficiency was obtained by taking advantage of the free Cl
2
gas generated
at the anode and transported to the cathode in a closed system. Reduced power
consumption with higher volumes of produced water was achieved in the closed system.
It is important to note that enough all the metals exhibited a similar w-shape
pattern as can be seen in Figures 3-82 through 3-91, whereas the closed system test
revealed higher removal efficiency at the fourth of five tested locations along the core
length of 22.5 cm.
Figures 3-94 through 3-99 displayed results of a second set of tests to illustrate
the effect of chlorine gas on removal efficiency. In both tests the application of EK was
interrupted in a certain fashion to limit the production of chlorine. (interruption for a
period of 8 hours after each 8 hours of EK application. These results compared to
continuous EK application over 24 hours). It was clearly demonstrated that in the case of
interruption the chlorine gas generation was restricted and, therefore, didn’t go into
solution to reduce the pH, and improve the efficiency of metal control capability as well
as the potential of pressure displacement. In addition, the continuous system had a steady
current induced over a longer period of time promoting more successful electrokinetic
149

application to allow for better transport of metals to take place.
The continuous application of D.C. in closed system gave better results than
interrupted application of D.C. Final pH at the cathode was reduced with the aid of
transported Cl
2
gas. Further studies are required to identify the optimum amount of
chlorine gas to better control pH, further increase electroremediation performance, and
reduce power consumption.

150

Figure 3-80: Variation of voltage with time for samples No.1 and No.2. Sample length =
30 cm; treatment time= 24 hours.

151

Figure 3-81: Variation of power with time for samples No.1 and No.2. Sample length =
30 cm; treatment time= 24 hours.

152

Figure 3-82: Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

153

Figure 3-83: Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

154

Figure 3-84: Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

155

Figure 3-85: Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

156

Figure 3-86: Concentration of Cr upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

157

Figure 3-87: Concentration of Cr upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

158

Figure 3-88: Concentration of Cs upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

159

Figure 3-89: Concentration of Cs upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

160

Figure 3-90: Concentration of Zn upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

161

Figure 3-91: Concentration of Zn upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 24 hours.

162

Figure 3-92: Variation of voltage with time for samples No.3 and No.4. Sample length =
30 cm; treatment time = 40 hours. (with two 8-hour interruptions.)

163

Figure 3-93: Variation of power with time for samples No.3 and No.4. Sample length =
30 cm; treatment time = 40 hours. (with two 8-hour interruptions.)

164

Figure 3-94: Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours. (with two 8-hour interruptions.)

165

Figure 3-95: Concentration of Al upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours. (with two 8-hour interruptions.)

166

Figure 3-96: Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours. (with two 8-hour interruptions.)

167

Figure 3-97: Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours. (with two 8-hour interruptions

168

.

Figure 3-98: Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours. (with two 8-hour interruptions.)

169

Figure 3-99: Concentration of As upon EK treatment along the core length of 30 cm.
Potential gradient = 3.5 V/cm, Treatment time = 40 hours. (with two 8-hour interruptions.)
170

Chapter 4

Conclusions

In my study, I stressed gathering and classification of necessary data and the procedures
of decision making aimed at identification and selection of the optimum operational
parameters in up-scaling for electroremediation of heavy metals from offshore muds.
It is necessary to emphasize that the best remediation results are achieved in situ
using a combination of various cleaning technologies. Only a few publications attempt to
integrate the results of various disciplines (geology, geochemistry, chemistry, physics,
etc.) into integrated study on industrial application of electrokinetics for decontamination
of metals and hydrocarbons (Chilingar et al., 1997).
The main role in such a study must be given to the procedures of gathering and
classifying the necessary data and procedures of decision making aimed at identification
and selection of the best combination of remediation technologies (Chilingar et al., 1997).
The most critical parameter is the voltage gradient applied to decontaminate heavy metals:
- Al, As, Cr and Cs all had the highest removal efficiency using 1 V/cm for a
sample length of 10 cm and 3 V/cm for sample length of 30 cm.
- Se and Zn had the highest removal efficiency using 2 V/cm for a sample length of
20 cm, and 3 V/cm for sample length of 30 cm.
- Pb had the highest removal efficiency using 3 V/cm for a sample length of 10, 20
171

and 30 cm
Higher removal efficiency was achieved in longer tests even when using the non-
optimum voltage gradient. The high salinity of Abu Dhabi’s sea water is believed to
contribute to the large flows achieved. These results indicate that sustainable in-situ
electroremediation of heavy metals in high-salinity environments such as offshore muds
is feasible.
In the case of tests involving Cl
2
gas, in a closed system with a potential gradient of
3.5 V/cm, removal efficiency was higher than in the open system with 3.5 V/cm electric
potential. Higher removal efficiency was obtained by using the free Cl
2
gas generated at
the anode and transported to the cathode in a closed system. Reduced power consumption
with higher volumes of produced water was achieved in the closed system.
In this study, the continuous application of D.C. in closed system gave better results
than interrupted application of D.C. Final pH at the cathode was reduced with the aid of
transported Cl
2
gas.
The chlorine gas can have two impacts on the transport of metals in the system. One
is to oxidize the metal ions to a higher oxidation state and the second is to form chloride
complexes which will have higher mobility in the system.
In conclusion, it appears that presence of Cl
2
gas improves the efficiency of
remediation.
The experiments conducted by the writer on field-collected offshore mud samples
demonstrate that electroremediation is a very promising solution. At this stage, it is
probably necessary to conduct a pilot test in situ.
172

References

Ace, A. G. 1955. An investigation of the influence of applied electrical potential
gradients on flow of fluids in porous media. M.S. Thesis, Department of Petroleum
Engineering, The University of Southern California, Los Angeles, CA.

Acar, Y. B., Gale, R. W., Hamed, J. and Putman. G. , 1990. Transportation Research
Record, 1288, pp. 23-24. Transportation Research Board, National Research Council,
Washington,D.C.

Adamson, L. G., Amba, S. A., Chilingar, G. V. and Beeson, C. M. ,1963a. Possible use of
electric current for increasing volumetric rate of flow of oil and water during primary or
secondary recovery. Chimika Chronika, 28(1):1-4.

Adamson, L. G., Chilingar, G. V. and Beeson, C. M., 1963b. Some data on electrokinetic
phenomena and their possible application in petroleum production. Chimika Chronika,
28(10):121-127.

Adamson, L. G., Chilingar, G. V., Beeson, C. M. and Armstrong, R. A., 1966.
Electrokinetic dcwatering, consolidation and stabilization of soils. Engineering Geology,
1:291-304.

Al-Sharhan, A.S. and El-Sammak, A.A., 2004, Grain size analysis and characterization of
sedimentary environments of the United Arab Emirates coastal area, J. of Coastal
Research, 20 (2): 464-477.

Ambah, S. A., Chilingar, G. V. and Beeson, C. M., 1964. Use of direct electrical current
for increasing the flow rate of reservoir fluids during petroleum recovery. J. of Canadian
Petroleum Technology, 3(1):8-14.

Ambah, S. A., Chilingar, G. V. and Beeson, C. M., 1965. Application of electrical current
for increasing the flow rate of oil and water in a porous medium. J. of Canadian
Petroleum Technology, 4(2): 81-85.

Ambah, S. A., Chilingar, G. V. and Beeson, C. M., 1965. Application of electrokinetic
phenomena in civil and petroleum engineering. Annals NewYork Acad. of Sci.,
118(14):585-602

Atlas, R. M. 1977. Stimulated petroleum biodegradation. Critical Reviews in
Microbiology, 5:371-386.

173

Atlas, R. M. 1981. Microbial degradation of petroleum hydrocarbons. Microbiological
Reviews, 45:180-209.

Bell, C. W., and Titus, C. H., 1973, Electro-Thermal Process for Production of Offshore
Oil through Onshore Wells, US Patent No. 3,724,543.

Bell, C. W., and Titus, C. H., 1974, Electro-Thermal Process for Promoting Oil Recovery,
US Patent No, 3,782,465.

Bell, C. W., Titus, C. H., and Wittle, J. K., 1985,"In Situ Method for Yielding a Gas from
a Subsurface Formation of Hydrocarbon Material, US Patent No. 4,473,114.

Bell, G, T., 1957, Electrolytically Promoting the Flow of Oil from a Well, US Patent No.
2,799,641.

Bcar, J. 1973. Dynamics of Fluids in Porous Media, 764 pp. Elsevier, Amsterdam.

Bhandari, A., Dennis, C. D. and Novak, J., 1994. Soil washing and biotreatment of
petroleum-contaminated soils. J. of Environmental Engineering, 120(5):1151-1169.

Blacker, S. and Goodman, D., 1994. Risk-based decision making ease study: Application
at a Superfund cleanup. Environmental Science and Technology 28(11):471-477.

Briant, J. 1961. Theses: Les phenomenes electrocinetiques en milieu hydrocarbure et
l’epaissuer de la double couche. La revue de l’institut Francais du petrole et annals des
combustibles liquids. XVI, 6; 1 – 48; (7-8): 49 – 75.

Burnett, W. E., and Loo, W. W., 1994. In-situ bioremediation of gasoline in soil and
groundwater: A case history. Paper presented at the Superfund XV Conference,
Washington, D. C.

Casagrande, I. L. 1937. Full-scsle experiment to incresse besring capacity of piles by
electrochemical treatment. Bautechnique 1(1): 14-16.

Casagrande, I. L. 1941. The drainsge of fine soils. Strasse 8(19/20): 324.

Casagrande, I. L.. 1941. On the problem of drsinage of fine soils. Stuttgart 36: 556.

Casagrande, I. L. 1947. The spplication of electroosmosis to practi- cal problems in
foundstions and earthworks. Building Res. Tech. Paper No. 30. Dept. Sci. Indust. Res.
London, England.

Casagrande, I. L. 1948. Electroosmosis. Proc. Second Int. Conf. Soil Mechanics. 1: 218-
223.
174

Casagrande, I.L., Bautechnique, 1949, 1(3): 1- 29.

Casagrande, I.L., Harvard Soil Mechanics, 1959, Ser. No.45

Casagrande,I.L., Soderman, L. G., and Loughney, R.W.,1960, ―Increase of Bearing
Capacity of Friction Piles by Electroosmosis,‖ ASCE Convention, Boston, Mass.

Chilingar, G. V. 1952. Possible utilization of electrophoretic phenomenon for separation
of fine sediments into grades. Journal of Sedimentary Petrology 22(1): 29-32.

Chilingar, G. V., Adamson, L. G., Armstrong, R. A. and Beeson, C. M., 1964. Soils
stabilized through electroosmosis. Southwest Builder and Contractor 145(24): 100-102.

Chilingar, G. V., Adamson, L. G. and Rieke, H. H., 1966. Notes on application of
electrokinetic phenomena in soil stabilization. In Proceedings of the International Clay
Conference, Jerusalem, Vol. 1, pp. 81 -89.

Chilingar, G. V., Adamson, L. G., Rieke, H. H. and Gray, R. R. 1968b. Electrochemical
treatment of shrinking soils. Engineering Geology 2(3): 197-203.

Chilingar, G. V., Amba, S. A. and Beeson, C. M., 1965. Application of electrokinetic
phenomena in civil engineering and petroleum engineering. Annals of the New York
Academy of Science 118(14): 585-602.

Chilingar, G. V., Beeson, C. M. and Amba, S. A., 1968a. Uso de corriente electrica
directa para aumentar la proportion del fluxo de fluidos en 10s yacimientos: Effecto del
tipo de arcilla sobre la produccion de flujo. Ingenieria Petrolera 5(3): 22-32.

Chilingar, G. V ., Chang, K. S., Davis, J. E., Farhanghi, H. J., Adamson, L. G. and
Sawabini, S., 1968c. Possible use of direct electrical current for augmenting reservoir
energy during petroleum production. Compass of Sigma Gamma Epsilon 45(4): 272-285.

Chilingar, G. V., El-Nassir, A. and Stevens, R. G., 1970. Effect of direct electrical current
on permeability of sandstone cores. J. of Petrol. Tech. 22(7): 830-836.

Chilingar, G. V., Loo, W.W., Khilyuk, L.F. and Katz, S. A., 1997. Electrobioremediation
of soils contaminated with hydrocarbons and metals: progress report. Energy Sources,
19:129-146.

Chilingar, G. V., Buryakovsky, L.A., Eremenko, N.A., and Gorfunkel, M.V., 2005.
Geology and Geochemistry of Oil and Gas, Elsevier, 370 pp.

175

Cozzarelli, I. M., Herman, J. S. and Baedecker, M. J., 1995. Fate of microbial metabolites
of hydrocarbons in a coastal plain aquifer: The role of electron acceptors. Environmental
Science and Technology 29: 458-469.

El Gawad, E. A., Lotfy, M.M. and Sadooni, F.N., 2008, Sedimentology and hydrocarbon
potentiality of arid Sabkha, UAE., J. of Applied Sciences Research, 4 (9): 1124-1130.

Fairless, B. 1990. Applying total quality principles to Superfund planning, Part 11:
DQOS in Superfund-A dioxin case study. In: Proc. American Society of Quality Control
17thAnnual Meeting, Enew Division Session L, Tucson, Arizona, 17-21.

Haroun, M. H. 2009. Feasibility of in-situ Decontamination of Heavy Metals by
Electroremediation of Offshore Muds. Doctoral Dissertation in Environmental
Engineering, University of Southern California, 313 pp.

Harton, J. H., Hamid, S., Abi-Chedid, E. and G. V. Chilingar. 1967. Effect of
electrochemical treatment on selected physical properties of clayey silt. Engineering
Geology 2(3): 191-196.

Hicks, R. E. and Tondorf. S., 1994. Electrorestoration of metal contaminated soils.
Environmental Science and Technology 28(12): 2203-2210.

Hinchee, R. E., Downey, D. C., Dupont, R. R., Aggarwal, P. K. and Miller, R.,
1991.Enhancing biodegradation of petroleum hydrocarbons through soil venting. J.
Hazardous Materials 27: 315-325.

Hopper, D. R., 1989. Cleaning up contaminated sites. Chemical Engineering, August: 94-
110. Huesemann, M. H., 1994. Guidelines for landtreating petroleum hydrocarbon
contaminated soils. J. Soil Contamination, 3:299-318.

Huesemann, M. H. 1995. Predictive model for estimation of extent of petroleum
hydrocarbon biodegradation in contaminated soils. Environmental Science and
Technology, 29(1): 7-18.

Katz, S. A., Khilyuk, L. F. and Chilingar, G. V., 1996. Sensitivity analysis and
multivariant modeling for formation pressure and temperature fields in inhomogeneous
media. J. Petroleum Science and Engineering 1695-108.

Kendall, C. G., Alsharhan, A.S. and Whittle, G.L., 1995. Holocene carbonate/evaporites
of Abu Dhabi, United Arab Emirates-Field trip guidebook, International Conference on
―Quaternary Deserts and Climatic Change,‖published by the United Arab Emirates
University.

Kruyt,H.R., 1952. Colloid Science, 1: 389. Elsevier Pub. Co., New York, N.Y.
176

Lancelot, F., Londiche, H. and De Marsily, G., 1990. Experimental results on the
influence of electric fields on the migration of oil, ionic species and water in porous
media. J. Petroleum Science and Engineering, 4: 67-74.

Langnes, G.I., Robertson, J.O., and Chilingar, G.V., 1972. Secondary Recovery and
Carbonate Reservoirs, Elsevier, 304 pp.

Leahy, J. G., and R. R. Colwell. 1990. Microbial degradation of hydrocarbons in the
environment. Microbiology Review, (54): 305-315.

Lee, M. D., Thomas, J. M., Borden, R. S., Bedient, P. B., Ward, C. H. and Wilson, T. J.,
1988. Biorestoration of aquifers contaminated with organic compounds. CRC Critical
Reuiews in Environmental Control, 18: 29-89.

Loo, W. W. 1991. Heat enhanced bioremediation of chlorinated solvents and toluene in
soil. Pmc. of HMCRI R & D Conf., Anaheim, Calif., pp. 133-136.

Loo, W.W. 1993. Biotreatment of chlorinated solvents in soil and groundwater utilizing
glucose as the co-substrate. Paper presented at the Hazmacon Conf., San Jose, Calif.

Loo, W. W. 1994. Electrokinetic enhanced passive in situ bioremediation of soil and
groundwater containing gasoline, diesel and kerosene. Paper presented at the Hazmacon
Conf., San Jose, Calif.

Loo, W. W., Wang, I. S. and Fan, K. T., 1994. Electrokinetic enhanced bioventing of
gasoline in clayey soil: A case history. Paper presented at the Superfund XV Conference,
Washington, D. C.

Mahaffey, W. R., Compeau, G., Nelson, M. and Kinsella, J., 1991. Developing strategies
for PAH and TCE bioremediation. Wafer and Environmental Technology: 3233-86.

McCarty, P. L. 1991. Engineering concepts for in situ bioremediation. J. Hazardous
Materials 28: l-10.

Mitchell,J. K., 1993, Fundamentals of Soil Behaviour, John Wiley and Sons, Inc., New
York.

Morgan, P. and Watkinson, R. J., 1989. Hydrocarbon degradation in soils and methods
for biotreatment. Critical Reuiews in Biotechnology 8:305-333.

Nash, J. H. and Traver, R. P., 1988. Field application of pilot soil-washing system. EPA
Document EPA/68-03-3450. Office of Research and Development, US. Environmental
Protection Agency, Cincinnati, Ohio.

177

Nunno, T. J., Hyman, J. A. and Pheiffer, T. H., 1988. Assessment of international
technologies for Superfund applications. EPA Document EPA/540/2-88/003, 37 pp.
Office of Solid Waste and Emergency Response. U.S. Environmental Protection Agency,
Washington, D.C.

Overbeek, J. T. and Lijiklema, J, 1969, Electric Potential in Colloidal Systems,
Electrophoresis, M. Bier, Ed., Academic Press, New York, 25-35.

Pamukcu, S. and Wittle, J.K. 1993. Electronically enhanced in-situ soil decontamination.

Pamukcu, S. and Wittle, J.K. 1993. Electrokinetic treatment of contaminated soils,
sludges and lagoons. DOE Contract No. 02112406.

Pamukcu, S. and Wittle, J.K. 1994. Electrokinetic removal of coal tar constituents from
contaminated soils. EPRI TR-103320, Project 2879-21.

Pamukcu, S., Weeks, A. and Wittle, J.K. 1997. Electrochemical extraction and
stabilization of selected inorganic species in porous media. J. hazardous materials, 55,
305 – 318.
Pamukcu, S., Weeks, A. and Wittle, J.K. 2004. Enhanced reduction of Cr(VI) by direct
electrical current in a contaminated clay. Environmental Science Technology, 38, 1236 –
1241.
Pamukcu, S., L. Hannum, J.K. Wittle, 2008. Delivery and Activation of Nano-iron by DC
Electric Field, J. Environ. Sci. Health, Part A,43 (8): 934-944.

Pheiffer, T. H. 1990. EPA's assessment of European contaminated soil treatment
techniques. Environmental Progress 49582-587.

Pheiffer, T. H. 1990. EPA's assessment of European contaminated soil treatment
techniques.Environmental Progress 49582-587.

Pollard, S. J. T., Hmdey, S. E. and Fedorak, P. M., 1994. Bioremediation of petroleum
and creosote-contaminated soils: A review of constraints. Waste Management and
Research 12:173-194.

Probstein, R. F., Renaud, P. S. and Shapiro, A. P., 1991. Electroosmosis techniques for
removing hazardous materials from soil. US. Patent 5074986.

Raymond, R. L., Hudson, J. O. and Jamison, V. W., 1976. Oil degradation in soil.
Applied Environmental Microbiology 31: 522-535.

Renaud, P. S., and Probstein, R. F., 1987. Electroosmotic control of hazardous waste.
PhysicoChemical Hydrodynamics 9(1/2): 345.
178

Rudenberg,P.A. 1945. Grounding principle and practice. Elect.Engr. 64 (1):1-15
Shapiro, A. P., and Probstein, R. F., 1993. Removal of contaminants from saturated clay
by electroosmosis. Environmental Science Technology 27(2): 283-291.

Shapiro, A. P., Renaud, P. S. and Probstein, R. F., 1989. Preliminary studies on the
removal of chemical species from saturated porous media by electroosmosis.
PhysicoChemical Hydrodynamics 11(5/6):785.

Shin,S., Haroun,

M., Ghosh,B., Pillay, A., Al Badawi,M., Chilingar, G.V ., Pamukcu, S.,
and Wittle, J.K., 2010 Electroremediation of Heavy Metals from Offshore Muds upon
Partial Chlorine Gas Removal. The 9
th
Symposium on Electrokinetic Remediation (EREM
2010) June 27-30, Kaohsiung, Taiwan

Sims, R. S. 1990. Soil remediation techniques at uncontrolled hazardous waste sites: A
critical review. J. the Air Waste Management Association 40: 704-732.

Smoluchowski, von M. 1921. Handbuch der Electrizitat und des Magnetismus, 11.
Translated by P. E. Bocque. In. Engineering Research Bulletin 33:47-158.

Stinson, M. K., H. S. Skovronek, and W. D. Ellis. 1992. EPA Site demonstration of the
BioTrol soil washing process. J. the Air and Waste Management Association
42:96-103.

Street,N.,1961. Electrokinetic effects in laboratory permeability measurement: Produces
monthly,25, 1:12-14

Titus, C.H., Wittle, J.K. and Bell, C.W., 1985, Apparatus for Passing Electrical Current
Through an Underground Formation, US Patent No.4,495,990.

Ungcrcr, P., Burrus, J., Doligez, B., Chenet, P. Y. and Bessis, F., 1990. Basin evaluation
by integrated two-dimensional modeling of heat transfer, fluid flow, hydrocarbon
generation, and migration. Petroleum Geology Bulletin 74(3):309-335.

Visschcr, K., Brinkman, J. and Soczo, E. R., 1990. Biotechnology in hazardous waste
management in the Netherlands. In Biotechnology and Biodegradation: Advances in
Applied Biotechnology, 4: 389-403. Gulf Publ. Co., TX.

Winterkorn, H. F. 1947. Fundamental similarities between electroosmotic and
thermooamotic phenomena. Proc. Highway Res. Bd. 27: 443- 455.

Winterkorn, H. F. 1948. Physicochemical properties of soils. Proc. Second Into Con£.
Soil Mechanics. 1: 23-29.

179

Winterkorn, H. F. 1952. Surface-chemical properties of clay miaersls and soils from
theoretical snd ..xperimental developments in electroomosis. ASTM Symposium on
Exchange Phenomena in Soils. Spec. Tech. Pub. No. 142. : 44-52.

Winterkorn, H. F. 1955. Water movement through porous hydrophilic systems under
capillary, electrical, and thermal potential. ASTM Symposium on Permeability of Soils.
Spec. Tech. Pub. No. 163.: 27-35.

Wittle, J. K., and Bell, C. W., 2005a, Electrochemical Process for Effecting Redox-
Enhanced Oil Recovery, US Patent No. 6,877,556 Bl.

Wittle, J. K., and Bell, C. W., 2005b, Method for Enhancing Oil Production Using
Electricity, US Patent Application No. 2005/0199387 AI.

WillIe, J. K., and Hill, D. G., 2006a, Use of Direct Current Electrical Stimulation for
Heavy Oil Production, Society of Petroleum Engineers Applied Technology Workshop -
Technologies for Thermal Heavy Oil and Bitumen Recovery and Production, Calgary,
March 14 - 15.

WillIe, J. K., and Hill, D. G., 2006b, Direct Current Electrical Stimulation - A New
Approach to Enhancing Heavy Oil Production, First World Heavy Oil Conference,
Beijing, November 12 - 15.

Wittle, J. K., and Hill, D. G., 2006b, Direct Current Electrical Enhanced Oil Recovery in
Heavy-Oil Reservoirs to Improve Recovery, Reduce Water Cut, and Reduce H2S
Production while Increasing API Gravity, SPE. 114012-MS.

Wittle, J.K.; Hill, D.G. and Chilingar, G.V., 2008, Direct current electrical enhanced oil
recovery in heavy-oil reservoirs to improve recovery, reduce water cut, and reduce H
2
S
production while increasing API gravity, SPE 114012.

Wittle, J. K., Hill, D. G., and Chilingar, G. V., 2008a. Direct current stimulation for
heavy oil production. Paper 2008-374. Second World Heavy Oil Congress, Edmonton,
March 10–12.

Wittle, J. K., Hill, D. G. and Chilingar, G. V., 2011. Direct Electric Current Oil Recovery
(EEOR)—A New Approach to Enhancing Oil Production, Energy Sources, Part A:
Recovery, Utilization, and Environmental Effects, 33: 9, 805 — 822

Wilson, J. T., 1985. Biotransformation of soil. Applied Environmental Microbiology, 1:
242-243.

180

Appendix

New Technology (Electrokinetics) to Greatly Improve Acidizing
of Carbonate Reservoir Rocks (Possibly to Double Recoverable
Reserves)

As the writer was conducting experiments at the electrokinetics laboratories of Petroleum
Institute of Abu Dhabi, headed by Dr. Mohammad Haroun, he came up with an idea how
to improve acidizing operation in Petroleum Industry. The writer was working with Dr.
Haroun in Abu Dhabi for a period of 6 months.

The new technology proposed by the writer, Dr. M. Haroun, and G.V . Chilingar
is a real breakthrough, which will result in doubling recovery from tight carbonate
reservoirs (60 % of World oil reserves reside in carbonates).

This novel technology(electrokinetics) is proposed to improve acidizing
operations, i.e., increase the penetration distance. Aqueous solutions of hydrochloric acid
(usually 15%) are pumped into the carbonate formations to enlarge the pores and pre-
existing fractures. However, the penetration distance of acid is very short. By applying
D.C. current, one can drive the acid for long distances into the formation being acidized.

181

Introduction

Stimulation of carbonate reservoirs is achieved chiefly by acidizing treatments
(Hendrickson, 1972, p. 336). Acids may be injected into pores and pre-existing fractures
or at hydraulic fracturing rates depending upon the results desired. The acid dissolves the
carbonates (limestones/dolomites), enlarging the pores and increasing the width of pre-
existing fractures. This gives rise to an increase in permeability. The principal acid used is
hydrochloric (HCl), which is pumped through tubing.
In the case of acidizing through pre-existing fractures, with increasing width of
fractures, (1) the specific surface area decreases, (2) the spending time increases, and (3)
the penetration distance increases.
The main problem in acidizing is the fact that the radial distance the acid will
penetrate until being spent is short, especially in tight carbonates.
As shown in Eq. (A-1), in order to increase r
a
, either t or q
i
should be increased. As the
experimental data obtained by the writers indicate, the injection rate q
i
, can be increased
considerably by application of D.C. current (electrokinetic effect) (see Chilingar et al.,
1968,1970, for example).
On assuming a homogeneous formation, the volume of acid injected is equal to
the pore volume invaded [
i
𝑡 π ϕ ℎ 𝑟 a

𝑟 w

) ], the radial distance the acid will
penetrate until being spent, 𝑟 a
(ft), is equal to;

182

𝑟 a
√

i

π ϕ
𝑟 w

(A-1)

where,
i
= acid injection rate (bbl/min); 𝑡 = spending time (sec); ϕ = fractional
porosity; ℎ = formation thickness (ft); and 𝑟 w
= wellbore radius (ft).
In the case of uniform penetration of acid, the reaction rate declines uniformly with
decreasing acid concentration. The weight of carbonate dissolved per increment of
distance penetrated declines uniformly until the acid is completely spent. With stronger
acid, the spending time decreases.
In the case of matrix acidizing, with enlargement of pores, (1) the specific
surface area decreases, (2) the velocity decreases, (3) spending time increases, and (4) the
penetration distance increases.

183

Electrokinetics

When the imposed electrical potential gradient (E) is in the same direction as the pressure
drop, the flow rate increases:

t

𝐴 Δ
μ

𝐴

𝐸 μ
(A-2)

where:
t
= total volumetric rate of flow (electrokinetic plus hydrodynamic) ; k =
hydrodynamic permeability; A = cross-sectional area; L = length of porous media; Δ =
pressure drop; μ = viscosity; 𝑘 e

𝐷 ξ
π 𝐹 ) = the electrokinetic permeability; F =
formation resistivity factor (Archie’s); D = dielectric constant ; and ξ = zeta potential.
If Eq.A-2 is presented in a dimensionless form by normalizing the flow rates and,
thus, eliminating the viscosity, area and length terms:

t

i

e
𝐸 Δ
(A-3)

and

t

i
)

i

k
e
𝐸 k Δp
(A-4)

where
i
= initial hydrodynamic stabilized flow rate.
184

Equation A-3 shows that an increase in the flow rate in dependent upon the zeta
potential, dielectric constant, brine concentration, Darcy permeability, and pressure drop.
This equation also suggests that as the hydrodynamic permeability decreases, the percent
increase in flow rate due to electrokinetics will become more significant. It should be
remembered, however, that viscosity does change with increase in temperature, which
increases on application of an electrical potential. In tight formations, 𝑘 e
may exceed k
considerably.

185

Deployment System for Enhanced Acidizing

As shown in Fig.A-1 , using electrokinetics it is necessary deploy an anode in the well
adjacent to the formation being acidized, and cathode either at the surface or in the
adjoining well. The electrokinetic flow will occur from the anode to the formation to be
acidized, enabling the acid to move faster and deeper into the formation. The two
electrodes (anode and cathode) must be connected by cables to the Direct Current power
supply located on the surface. The acid must be injected with corrosion inhibitors into the
formation; however, the aluminum anode in bolehole may also serve as sacrificial anode
(Fig. A-1):

Figure A-1: Electrodes arrangement for acidizing operation
186

Conclusions

The proposed technology (electrokinetics) to improve acidizing operations is indeed a
breakthrough. By applying D.C current, the volumetric rate of flow increases, which, is
turn, increases the penetration distance of the acid before it is being spent. Without
application of D.C current, the penetration distance is usually very short, especially in
tight rocks.

187

Appendix References

Chilingar, G.V ., Chang Kim Sang, Davis, J.E., Farhanghi, H.J., Adamson, L.G., and
Sawabini, S.,1968. Possible use of direct electrical current for augmenting reservoir
energy during petroleum production. Compasss, 45(4): 272-285

Chilingar, G.V ., El-Nassir, A. and Stevens, R.G., 1970. Effect of direct electrical current
on permeability of sandstone cores. J. Petrol. Technol., (22): 830 – 836.

Chilingar, G.V ., Mannon R.W., and Rieke, H.H. Oil and Gas Production form Carbonate
Rocks, Elsevier, New York, 408 pp.

Chilingrian, G.V ., Mazzullo, S.V . and Rieke, H.H., 1972. Carbonate Reservoir
Characterization. A Geologic-Engineering Analysis, Part I, Elsevier, Amsterdam, 639 pp.

Herdrickson, A.R., 1972. Stimulation of Carbonate Reservoirs (Chapter 7), pp. 309-339.

Haroun, M.R., Chilingar, G.V ., Pamukcu, S., Wittle, J.K., Belhaj, H.A., Al Bloushi, M.N.,
2009. Optimizing Electroosmotic Flow Potential for Electrically Enhanced Oil Recovery
(EEOR
TM
) in Carbonate Rock formations of Abu Dhabi Based on Rock Properties and
Composition. IPTC13812, December, 2009.

Wittle, J.K., Hill, D.G., and Chilingar, G.V ., 2008, Direct Current Electrical Enhanced Oil
Recovery in Heavy-oil Reservoirs to Improve Recovery, Reduce Water Cut, and Reduce
H2S Production While Increasing API Gracity, SPE-114012, Society of Petroleum
Engineers.

Abstract (if available)

Abstract The electroremediation process requires much needed research work to be optimized for up-scaling and improving economic efficiency. This is particularly true when applying the technology to highly heterogeneous and complex mineralogy materials such as offshore sediments and muds. Laboratory batch tests were performed on field retrieved specimens of contaminated offshore muds near Abu Dhabi Ports of United Arab Emirates. The influence of various process parameters that determine the optimum operating conditions and sustainable enhancement of electrokinetic remediation was investigated. Excellent results of decontamination of seven heavy metals were achieved. ❧ The removal of heavy metals by management of the in-situ chlorine gas (Cl₂) production was also investigated. The tests showed a high removal efficiency of heavy metals at the cathode end of cores after 24 hours of EK application in the presence of chlorine gas. In the initial tests, high electrokinetic flow potential was achieved

Linked assets

University of Southern California Dissertations and Theses

Conceptually similar

PDF

Feasibility of in-situ removal of heavy metals by electroremediation of offshore muds

PDF

A risk analysis methodology to address human and organizational factors in offshore drilling safety: with an emphasis on negative pressure test

PDF

An ultrawideband digital signal design with power spectral density constraints

PDF

Superoxide radical and UV irradiation in ultrasound assisted oxidative desulfurization (UAOD): a potential alternative for green fuels

PDF

Application of the adaptive river management approach to Ayamama River in Turkey

PDF

Electrokinetic transport of Cr(VI) and integration with zero-valent iron nanoparticle and microbial fuel cell technologies for aquifer remediation

PDF

Oxidative potential of urban atmospheric particles: spatiotemporal trends and associations with source-specific chemical components

PDF

The use of carbon molecule sieve and Pd membranes for conventional and reactive applications

PDF

The extension of selective inhibition sintering (SIS) to high temperature alloys

PDF

Computationally efficient design of optimal strategies for passive and semiactive damping devices in smart structures

PDF

Bioelectrochemical treatment of anaerobic process effluents: mitigation of dissolved methane and sulfide

PDF

Semiconducting metal oxide nanostructures for scalable sensing applications

PDF

Optimizing biomembrane reactor systems for water reclamation and reuse applications

PDF

Investigating the temporal trends, sources, and toxicity of ambient particulate matter (PM) in different metropolitan environments, and development of a novel aerosol generation setup for inhalat...

PDF

Investigation of health system performance: effects of integrated triple element method of high reliability, patient safety, and care coordination

PDF

Energy control and material deposition methods for fast fabrication with high surface quality in additive manufacturing using photo-polymerization

PDF

Exploring properties of silicon-carbide nanotubes and their composites with polymers

PDF

Understanding human-building-emergency interactions in the built environment

PDF

Investigating the role of muscle physiology and spinal circuitry in sensorimotor control

PDF

Methanol synthesis in a membrane reactor

Asset Metadata

Creator Shin, Sanghee (author)

Core Title Electroremediation of offshore muds contaminated with heavy metals

School Viterbi School of Engineering

Degree Doctor of Philosophy

Degree Program Environmental Engineering

Publication Date 11/22/2011

Defense Date 10/25/2011

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag electrokinetics,electroremediation,heavy metals,nanotechnology,OAI-PMH Harvest,offshore muds,soil restoration

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Chilingar, George V. (committee chair), Meshkati, Najmedin (committee chair), Golomb, Solomon Wolf (committee member), Haroun, Muhammad (committee member), Pamukcu, Sibel (committee member)

Creator Email doolyloveme@hotmail.com,sangshin@usc.edu

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c3-211111

Unique identifier UC11291223

Identifier usctheses-c3-211111 (legacy record id)

Legacy Identifier etd-ShinSanghe-429-0.pdf

Dmrecord 211111

Document Type Dissertation

Rights Shin, Sanghee

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the a...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus MC 2810, 3434 South Grand Avenue, 2nd Floor, Los Angeles, California 90089-2810, USA