EPA/540/5-90/004
DEVELOPMENT OF ELECTRO-ACOUSTIC SOIL DECONTAMINATION (BSD)
PROCESS FOR IN SITU APPLICATIONS
by
H. S. Muralidhara, B. F, Jirjis, F, B. Stulen,
G. B. Wickramanayake, A. Gill, and R. E. Hinchee
Battelle
505 King Avenue
Columbus, Ohio 43201
January 18, 1990
Project Officer
Ms. Diana Guzman
Office of Research and Development
Superfund Innovative Technology Evaluation Program
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
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NOTICE
The information in this document has been funded by the U. S.
Environmental Protection Agency under Cooperative Agreement No.
815324-01-0 and the Superfund Innovative Technology Evaluation
(SITE) Program. It has been subjected to the Agency's peer review
and administrative review and it has been approved for publication
as a U. S. EPA document. Mention of trade names or commercial
products does not constitute an endorsement or recommendation for
use.
11
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FOREWORD
Today's rapidly developing and changing technologies and
industrial products and practices frequently carry with them the
increased generation of materials that, if improperly dealt with,
can threaten both public health and the environment. The U. S.
Environmental Protection Agency is charged by Congress with
protecting the Nation's land, air, and water resources. Under a
mandate of national environmental laws, the agency strives to
formulate and implement actions leading to a compatible balance
between human activities and the ability of natural resources to
support and nurture life. These laws direct the EPA to perform
research to define our environmental problems, measure the impacts,
and search for solutions.
The Risk Reduction Engineering Laboratory is responsible for
planning, implementing and managing research, development, and
demonstration programs to provide an authoritative, defensible
engineering basis in support of the policies, programs and
regulations of the EPA with respect to drinking water, wastewater,
pesticides, toxic substances, solid and hazardous wastes, and
Superfund-related activities. This publication is one of the
products of that research and provides a vital communication link
between the researcher and the user community.
An area of major concern is the environmental impacts
associated with sites contaminated with nonagueous phase liquids
and heavy metals. Because increasing proliferation of these wastes,
contamination of the ground and groundwater at a number of
locations is causing a serious threat to the environment. Hence,
the U. S. Environmental Protection Agency awarded this SITE Program
Cooperative Agreement to investigate the technical feasibility of
the electro-acoustic soil decontamination concept. This report
presents and discusses the development program which included a
literature review, soil characterization, design and construction
of a laboratory unit, and lab-scale experiments with soils
contaminated with and inorganic contaminants.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
111
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ABSTRACT
The technical feasibility of the electro-acoustic soil
decontamination (ESD) process through laboratory experiments clearly
demonstrated the removal/concentration of heavy metals such as cadmium and
zinc. Results of the decane contaminated soils were, however, inconclusive.
The ESD process is based on the application of a d.c. electric field
and acoustic field in the presence of a conventional hydraulic gradient to
contaminated soils to enhance the transport of liquid and metal ions through
the soils. Electrodes (one or more anodes and a cathode) and an acoustic
source were placed in contaminated soils to apply an electric field and an
acoustic field to the soil. This process works especially well with clay-
type soils having small pores or capillaries, where hydraulic permeability is
very low.
The development program included a literature review, soil
characterization, design and construction of the laboratory ESD unit, and lab-
scale experiments with soils contaminated with decane, zinc, and cadmium.
Evaluation of the experimental results clearly indicated that application of
the field forces reduced the heavy metals zinc and cadmium more than 90
percent in the treated cake. A maximum of 97.4 percent concentration
reduction in cadmium was achieved, and 92.3 percent concentration reduction in
zinc was obtained. Tests yielded 10-20 percent decane removal. The results
on the decane contaminated soil were inconclusive as a result of the large
discrepancy in the decane laboratory analysis.
IV
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CONTENTS
Figures vii
Tables ix
List of Abbreviations xj
Acknowledgement xii
1. Introduction : 1
2. Background 3
Electra-kinetic Phenomena Principles. 10
Electra-osmosis 10
Current Flow 14
Ion Migration 14
Ion Diffusion 15
Joule's Heating 15
Electrolysis 16
Acoustic Phenomena Principles 16
Combined Electra-acoustic Separation Principles 18
3. Project Planning 21
Quality Assurance Project Plan. 21
Material Selection and Characterization .... 22
Soil Types 22
Organic and Inorganic Contaminants 22
Electrical and Acoustical Properties 23
Experimental Investigation 23
Preparation of Soils 23
Bench Scale Study with a Test Unit 23
Acoustic Energy 25
Moisture Content 25
Treatment Duration 25
ESD Tests on Oecane 25
ESD Tests on Zinc 26
4. Experimental Investigation 28
Material Selection and Characterization 28
Soil Preparation 28
Decane Soil Preparation 28
Zinc Soil Preparation 31
Zinc-Cadmium Soil Preparation
Test Unit Design and Instrumentation. 3:
Test Cell 39
Decane Test Cell. 39
Zinc Test Cell. 39
Experimental Procedures ----------------- 41
Analytical Procedures 43
5. Experimental Results 45
Decane Experimental Results 45
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CONTENTS
(Continued)
Initial Decane Concentration 45
Effect of Electric Field on Decane Mobility 47
Effect of Electric Field and Time on Decane Removal . 47
Effect of Electric Field on Soil Moisture Content .. 49
Effect of Acoustic Field 49
Statistical Analysis on Tests 26D-30D 51
QC Assurance of Analytical Data: Decane. ______ 54
Zinc Tests 59
Results of Zinc Tests 59
Background on Electra-chemical Reactions of Zinc
at the Electrode 59
Effect of Time on Zinc Removal 60
Effect of Average Power on Zinc Removal 66
Effect of Acoustic Power and Frequency
on Zinc Removal 70
Zinc/Cadmium Test 75
Quality Assurance of Analytical Data: Zinc and Cadmium. . 78
QC Data for Zinc and Cadmium 84
Internal and External Quality Assurance Audits 84
6. Technical Performance of BSD with Other In-Situ Technologies. . 88
Organics Treatment 88
Pump and Treat 88
Soil Venting 91
Heat Enhances Soil Venting 91
Steam Injection 92
Radio Frequency Heating 92
Direct Current Heating 92
In-Situ Vitrification 92
Biodegradation 93
Meterials Treatment • 93
Direct Current 93
Pump and Treat 93
In-Situ Vitrification 94
7. Conclusions 95
8. Recommendations 96
9. References 97
Appendices
A. Decane Data A-l
B. Zinc Data B-l
C. Geochemical Calculations for Zinc Soil. • • C-l
D. Zinc/Cadmium Data D-l
E. Geochemical Calculation for Zinc Cadmium Soil E-l
vi
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FIGURES
Number Page
1 Conceptual Layout of Electra-acoustic Soil Decontamination 4
2 Electrical Double Layer and Zeta Potential
3 Structure of Soil Particle 19
4 Rearrangement of Particles from Application of Acoustic Field.... 20
5 Schematic of Laboratory Test Unit 36
6 Test Unit and Acoustic Instrumentation 37
7 Typical Acoustic Signals Acquired During Testing 38
8 Signals Indicating Nonlinear Interaction Between Drive Piston
and soi 1 column 38
9 Side View of Testing Cell for Electroacoustic Soil
Decontamination Process Used for Decane Soil Treatment 40
10 Side View of Modified Testing Cell for Electroacoustic Soil
Decontamination Process Used for Soil, Zinc/Cadmium
Soi 1 Treatment 42
11 Side View of the Treated ESD Cake in Decane Tests
(26D, 27D, 28), and 30D) Showing the Three Analyzed Layers 46
12 Top View of Decane Layer Showing how the
Layer was Divided and Analyzed 46
13 Side View of Decane-Treated ESD Cake Showing Layer
Moisture Content 50
14 Zande Measured Decane Concentration Plotted
Versus EPA Measured Concentration 56
15 Solubility of ZnO as a Function of pH 60
16 Schematic of the Cake-Divided Sections for Tests 7Z-16Z 63
17 Variation of Percent Zinc Removed/Accumulated as a Function of
Cake Gradient for 25 and 100 Hours' Leaching Time 64
vii
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FIGURES
(Continued)
-Number Page
18 Variation of Percent Zinc Removed/Accumulated as a
Function of Cake Gradient for 0, 0.013, 0.144 and 0.811
Average Power Input for 50 Hours' Leaching Time -68
19 Variation of Zinc Concentration as a Function of Cake Gradient at
0.013, 0.144 and 0.869 W Power Input for 50 Hours' Leaching Time 69
20 Variation of Zinc Removed (wt%) as a Function of Cake Gradient at
1.432 W and 0.390 W for 100 Hours' Leaching Time 71
21 Acoustic Input Power Versus Record Number -72
22 Schematic of Cake Divided Sections for Zinc/Cadmium Test -77
23 Distribution of Hydrolysis Products (x, y) at I = 1 m and 25' in
Solutions Saturated with fS-Cd(OH) -79
Vlll
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TABLES
Number Paqe
1 Applications of Electra-Osmosis in Soil Leaching, Consolidation,
and Dewatering -5
2 Zeta Potential of Soils -13
3 Particle-Size Distribution of Samples of the Soil -29
4 Soil Characteristics -30
5 Initial Percent Decane Contamination in Soil Before BSD,
Reported by Zande Lab -32
6 Initial Zinc Concentration in the Soil Reported by Zande 33
7 Initial Zinc and Cadmium Concentration in the Zinc/Cadmium Soil -34
8 Effect of Electric Field on the Decan Mobility 48
9 Statistical Analysis Results for Decane Tests -52
10 EPA and Zande Measured Decane Concentrations and Their
Differences in Soil (Dry Basis) -55
11 Comparative Analytical Determination of Decane in Soils by U.S.
EPA and Zande Laboratories 57
12 QC Data for EPA Analyses -58
13 Percent Ionic Distribution for ZnCl, at Ph 6 and 9.7 62
14 Sample Mass Balance Around the Zinc for Test No. 162 -64
15 Zinc Concentration at Different Cake Gradient for Different
Leaching Time -67
16 Acoustic Data for Zinc Experiments -73
17 Performance of ESD Process on Zinc/Cadmium Soil 76
18 Percent Ionic Distribution for ZnCl, and CdCl, at pH 7, 8, and 9. -80
19 Zinc QA Data 81
20 Analytical Data for Zinc Soil -82
21 Analytical Data for Cadmium in Soils -83
IX
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TABLES
(Continued)
Number paqe
-22 QC Data for Zinc 85
23 QC Data for Cadmium 86
24 Comparison of Electra-Acoustical Soil Decontamination (BSD)
to Other In-Situ Technologies 89
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ACKNOWLEDGEMENT
This report was prepared under the direction and coordination
of Diana Guzman, U. S. EPA SITE Project Manager in the Risk
reduction Engineering Laboratory, Cincinnati, Ohio. Reviewers for
this report were Denis Nelson, Chemical Engineer; Jonathan G.
Herrmann, Civil Engineer: Herbert R. Pahren, Chemical Engineer: and
David Smith, Quality Assurance Manager. All of the above
individuals are employees of the EPA's Risk Reduction Engineering
Laboratory in Cincinnati, Ohio.
This report was prepared for EPA's Superfund Innovative
TEchnology Evaluation (SITE) Program by H. S. Muralidhara, B. F.
Jirjis, F. B. Stulen, G. B. Wickramanayake, A. Gill, and R. E.
Hinchee of Battelle - Columbus for the U. S. Environmental
Protection Agency under Cooperative Agreement NO. CR815324-01-0.
XII
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SECTION 1
INTRODUCTION
Many sites in the U.S. are contaminated with nonaqueous phase liquids
(NAPL) and heavy metals'". The U.S. Environmental Protection Agency (U.S.
EPA) has estimated that 189,000 underground storage tanks are leaking at
retail fuel outlets alone. NAPL contamination in the form of coal tars and
petroleum sludges from above-ground tanks is also a significant problem.
Following a NAPL spill or release, the liquid typically migrates to the water
table where it spreads out and floats, since it is lighter than water. In a
typical cleanup, the initial phase recovers the free phase "floating" NAPL.
The fraction of spill which is recoverable utilizing conventional technology
is very low, and residual contamination following drainage of this recoverable
NAPL is very high, often in the range of several percent'2'.
Moreover, improper disposal of industrial wastes containing heavy metal s
has created a serious problem in a number of locations. Because of increasing
proliferation of these wastes, contamination of the ground and groundwater at
a number of locations is causing a serious threat to the environment.
The current state-of-the-art in remediating these sites is to recover all
pumpable separate phase organic liquids and then treat the residuals either
in-situ via bioreclamation, soil venting, soil washing or flushing, to pump
and treat, or to excavate. The initial recovery of pumpable product depending
upon the site, is typically limited to 20-25 percent recovery and in many
cases even less. Hence, the U.S. EPA awarded a Phase I Superfund Innovative
Technologies Evaluation program cooperative agreement to Battelle Columbus
Laboratories to demonstrate the technical feasibility of the ESD concept.
This technology will potentially increase the recovery rate and lessen the
need for follow-on residual clean up or reduce the cost where some follow-on
is required.
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This report provides the information related to technical feasibility of
Battelie's BSD technology. The report is organized as follows.
Background information related to prior art and theoretical principles on
electrokinetics and acoustics is provided in Section 3. Project planning,
including QA/QC plan, is given in Section 4. Experimental Investigation,
Results and Discussion are provided in Sections 5 and 6, respectively.
Technical performance of BSD with other in situ technologies on organic and
metal treatment is provided in Section 7. Summary, Conclusions, and
Recommendations are provided in Sections 8 and 9, respectively.
The project objective was to establish the feasibility of the in situ BSD
for decontaminating hazardous waste sites. The goals of the two-phase
developmental effort were to demonstrate the capability of this BSD process
to:
Decontaminate soils containing hazardous organics in situ by the
application of d.c. electrical and acoustic fields
Decontaminate soils containing heavy metals by the application of
d.c. electric and acoustic fields.
The program was proposed in two phases: Phase I - Laboratory
Investigation and Phase II - Field Demonstration. Phase I objectives were to
determine the effects of process parameters on BSD performance and to
recommend parameter ranges and a design to be evaluated in Phase II. Phase I
consisted of the following tasks:
Project Planning
• Material Selection/Characterization
• Parametric Investigations
Assessment of In-Situ Technologies
Final Report.
This Phase I report includes the background of BSD technology, mechanisms of
both the electric and acoustic fields, details of experimental setup, results
on decane, zinc, and zinc and cadmium, and summary conclusions of the
investigation.
A Phase II small scale field study on heavy metal decontamination is
needed to obtain further information related to specification and
configuration of the electrodes and acoustic driver in the field.
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SECTION 2
BACKGROUND
The BSD process is based on applying d.c. electric and acoustic fields to
contaminated soils to obtain increased transport of liquids and metal ions
through the soils. Figure 1 illustrates the operating principle of the
process. Electrodes (one or more anodes and a cathode) and an acoustic source
are placed in a contaminated soil to apply the electric and acoustic fields to
the soil. Increased transport of liquids through the soil is obtained by
applying the electric and acoustic fields. The process is expected to be most
effective for clay-type soils having small pores or capillaries, in which
hydraulic permeability is very slight.
The dominant mechanism of the enhanced flow is electroosmosis
resulting from the electric field. In-situ electro-osmosis was first
successfully applied to soils by L. Casagrande in the 1930s in Germany for
dewatering and stabilizing soils'34'. Recently, Muralidhara and co-workers
at Battelle have discovered that the simultaneous application of an electric
field and an acoustic field produces a synergistic effect and results in
further enhancement of water transport'514'. This Battelle's process is
termed electro-acoustic dewatering (EAD). Battelle is actively engaged in the
development and commercialization of the EAD process for a variety of
industrial and wastewater treatment applications.
Based on our extensive research and development experience in the
application of electric and acoustic fields to dewatering and proven soil
dewatering technology utilizing electroosmosis, Battelle is utilizing the
principles of EAD technology to decontaminate soil in-situ. Background
information on theories and operating principles is provided in the following
sections. Prior related applications are summarized in Table 1.
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Flushing (Optional)
Pumping Contaminants
with Croundnater
Acoustic Source
Ground Surface
Anode
On $• tort ted lorit
Water Table
lAcoustf
Waves
Zone
Contaminant
(NAPL)
Cathode
Steel Recovery Well
(with 2 pumps system)
i. - J
Figure 1. Conceptual Layout of Electra-acoustic Soil Decontamination
(Final design may vary based upon laboratory testing).
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TABLE
APPLICATIONS OF ELECTROOSMOSIS IN SOIL LEACHING, CONSOLIDATION, AND DEWATERING
Application
Leaching of Cr
from soils
Leaching of Cr
from soils
ul
Crude oil
product i on
Investigators
Banerjee^ '
Scale of
Operation
Voltage and Current
Horng et al.
(23)
Laboratory
Laboratory and
field
0.1 to 1.0 V/cm
N/A
Anbah et al.
(24)
Laboratory
N/A
Results and Comments
Obtained increased
leaching rate with
electric field
Obtained increased
leaching rate with
electric field;
determined effect
of anode materials
Obtained increased
flow of oil -water
mixture through
porous media; de-
termined beneficial
effect of a small
addition of elec-
trolyte to kerosene
to obtain increased
electroosmotic flow
Soil consolidation Hardy
Laboratory and
field
N/A
Treated highly
plastic clays with
liquid limits
ranging from 45 to
107 and plasticity
indices ranging
from 27 to 28 and
achieved 300 per-
cent increase in
the strength of the
clay
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TABLE 1. (CONTINUED)
Application
Investigators
Scale of
Operation
Voltage and Current
Leaching of salts Probstein et al. (27) Laboratory
and organic acid
1-1.5 V/cm
Soil consolidation Mitchell et al.
(28)
Laboratory
and theoretical
development
0.75 V/cm
Results and Comments
Looked at model
systems such as
Kaolin clay satur-
ated with organic
acid cacetic acid.
Results suggest
that current
efficiency
increases with
increase in
concentration which
is contrary to
predictions.
An excellent paper
on theoretical
aspects of electro-
osmosis applied to
soil consolidation
systems
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TABLE 1. (CONTINUED)
Application
Investigators
Scale of
Operation
Voltage and Current
Enhanced oil
recovery
Fleureau et al.
(30)
Laboratory
N/A
Electroreclamat i on
in soils
Lageman
(Geokinetics N.L.)
Field
Field Study
Results and Comments
• Experiments de-
termined the
influence of
electrochemical
phenomena on
interfacial tension
and wettability
parameters. They
observed in-situ
formation of the
surfactants which
was responsible for
reducing inter-
facial tension
• Decontamination of
heavy metals
especially AS.Cd,
CO, Cr, Cu, Ag, Ni,
Mn, Mo. About 90
percent removal
claimed. Remed-
iation costs
ranging from $50
per ton to $400 per
ton.
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TABLE 1. (CONTINUED)
Application
Investigators
Scale of
Operation
Voltage and Current
Results and Comments
Soil dewatering
(Salzgitter,
Germany)
Casagrande^2'3)
Field
180 V 9.5 A/Well
00
(2
Soil dewatering Casagrandev '
(Trondheim, Norway)
Field
40 V 26 A/well
Dewatering of
waste suspensions
Kelsh
(29)
Lab and Field
N/A
. Electrodes placed
22.5 ft deep and
15 ft apart; flow
rate increased by a
factor of 150 from
10 gal/day well
without electric
field to 1500
gal/day/we11 with
electric field;
energy usage was
0.38 kwh/gal.
• Electrodes placed
60 ft deep and 15
ft apart; flow rate
increased from 6
300 gal/day/we11 to
70-3040 gal/day/
well; energy usage
was 0.30 kwh/gal.
. Applications of
electrokinetics to
number of waste
streams such as
slimes, ultrafine
coal waste, mine
tailings pulp, and
paper mill sludges.
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TABLE 1. (CONTINUED)
Application
Investigators
Scale of
Operation
Voltage and Current
Electroreclamat i on
of contamianted
soils
Hammett
(26)
Lab
N/A
Desalting from
soils
Lab and Field
50 V/in.
Electroosmotic
dewatering
Lockhart
(31)
Lab and Field
N/A
Results and Comments
Very informative
background work and
good discussion on
electrokinetic
aspects of trans-
port of contam-
inants in the soil.
An interesting
approach to trans -
port salt from
soil. It is poss-
ible to selectively
transport (P04),
(N03) to the root
zone.
Applications of
electrokinetics to
dewatering of
minerals, coal and
a very good inter-
pretation of
mechanisms of
electroosmosis
dur i ng dewater i ng.
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ELECTRO-KINETIC PHENOMENA PRINCIPLES
The application of a d.c. electric field to a soil high in clay content
results in the following phenomena:
Electra-osmosis
• Electra-phoresis
Current flow
Ion migration
• Joule's heating
Ion diffusion.
Each of these has implications for the design and operation of BSD processing
schemes, which are discussed in the following sections.
Electro-osmosis
Electro-osmosis^ ' ' in porous media, such as clays, is due to an
electrical double layer of negative and positive ions formed at the solid-
liquid interface. For soil particles, the double layer consists of a fixed
layer of negative ions that are firmly held to the solid phase and a diffuse
layer of positive ions that are more loosely held. Application of an electric
potential on the double layer results in the displacement of the two layers to
respective electrodes; i.e., the positively charged layer to the cathode and
the negatively charged layer to the anode.
Since the particles in the soils are immobile, the fixed layer of the
negative ions is unable to move. However, the diffuse layer containing
positive ions can move and drag water along with it to the cathode. This is
the basic mechanism of electro-osmotic transport of water through wet soils
under the influence of an applied electric potential. Figure 2 shows the
electrical double layer and zeta potential.
The rate of flow by electroosmosis through a single capillary is given by
ju, . (3,15)
the expression
EDr2Z
Q = 4nL
10
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Solid Phase
//// / I /1 11 I I I I I I
Fixed Layer
Zeta + + - + + + - + + +
Potential Diffuse Layer
+ - + + - + + + -+ (Mobile)
Figure 2. Electrical Double Layer and Zeta Potential^ '
11
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o
where Q = electro-osmotic flow rate, cm /sec
E = applied electric potential, volts
L = length of capillary between electrodes, cm
D = dielectric constant of the liquid „
g = viscosity of the liquid, dynes-sec/cm
Z = zeta potential, volts x 10
r = radius of capillary, cm
The above expression is valid for soils where pore diameters are large
compared with the thickness of the double layer. The electro-osmotic flow
velocity (U cm/sec) is obtained by dividing the flow rate, Q, by the cross-
0
sectional area of the capillary (pr ) as follows:
EDZ
U = 4pgL
The above expression indicates that the electro-osmotic flow velocity is
independent of the capillary diameter, a key advantage of electro-osmosis over
conventional flow under a pressure gradient. In the absence of an electric
field, the flow of water through small pores essentially stops.
An important parameter of electro-osmotic flow is the zeta potential, Z,
which is the potential drop across the diffuse part of the electric double
layer that controls electro-osmosis. It represents the electro-kinetic charge
which exists at the sol id-liquid interface of particles in suspension.
Typical values of zeta potential reported by Hunter^5' for various types of
soils are given in Table 2. The data indicate that electro-osmosis is more
efficient in clay-type soils than in sandy soils.
Some noteworthy examples of the prior work on soil leaching,
consolidation, and dewatering by electro-osmosis are summarized in Table 1.
Numerous patents have been issued in various applications of electric field
for enhanced recovery of crude oir ' The examples demonstrate the
feasibility and practicality of electro-osmosis in large-scale applications.
The reported electrical energy consumption in the range of 0.3 to 0.4 kwh/gal
is low and should be acceptable for soil decontamination applications
($0.015/gal to $0.020/gal power cost). The examples of metal leaching, oil
recovery, and Casagrande's work in particular on soil dewatering clearly
indicate that the application of the electric field has been successful enough
to suggest that Battelle's BSD technology would perform adequately at pilot-
scale levels and, eventually, full-scale levels.
12
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TABLE 2. ZETA POTENTIAL OF SOILS*
Type of Soil Zeta Potential (mV)
Lithium vermiculite -80
Sodium bentonite -40
Silica sand -10
Quartz sand - 25
Kaolin clay -80
* Ref. 15
13
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Current Flow
When a voltage is applied across an electrolyte solution, there is a
current flow that is proportional to the electrical conductivity (or inversely
proportional to the resistance) of the solution. This is the familiar Ohm's
law:
I = E/R (1)
where I (amps) is the current, E (volts) the applied voltage, and R (ohms) the
electrical resistance. The resistance decreases as ionic strength increases
and as the temperature increases.
During the ESD process, it is desirable to minimize the current flow for
a given zeta potential to reduce power consumption and to minimize the Joule
heating; a discussion of current flow phenomenological effects follows.
Ion Migration
When a direct current is passed through an electrolytic solution, the
cathode acts as a source of electrons and the anode acts as an electron sink.
Positive ions will travel toward the negative electrode (cathode), whereas
negative ions will travel toward the positive electrode (anode). The positive
ions have a tendency to accept electrons at cathode surface and negative ions
electrons at the anode surface. The overall transport of ions in the bulk
medium is defined as ionic migration.
Flux of ionic species in the presence of a d.c. electric field is given
by:
p
Ji = viCiE, flux of i species moles/sec cm
v. = ionic mobility of i species cmVsec/volt
C= = concentration of i species, moles/cm3
E = electric field, E/cm
The ionic mobility is the speed at which the ion moves toward the
respective electrode in the applied electric field. This speed is determined
by the viscosity of solvent, the conductivity of solvent, the strength of the
applied field, and the size and the shape of the ion.
14
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Ion Diffusion
Ionic diffusion is another phenomenon that occurs in an electrolysis
medium in the presence of a d.c. electric field. The concentration of ions
near the electrode is always higher than the bulk concentration. This
enrichment of ions near electrode surface promotes flow of ions from a higher
to lower concentration.
Ionic flux results from diffusion is given by:
J, = D| YC.
Jj = flux of i species moles/sec cm
D = diffusion coefficient cm /sec „
Cj = concentration of i species moles/cm15
Ion transport resulting from convection is rather minimal in in-situ treat-
ment, due to the nature of flow in the soil medium.
Joule's Heating
When a current passes through a solution, the electrical energy is
converted to heat according to the equation
q = El
where q (cals/sec) is the heating rate, E (volts) is the applied voltage, and
I (amps) the electric current through the solution. This heating of the
solution is called Joule's heat. The temperature increase of the soil may be
approximated as
£L
tout - tin = FCP
where F (gm/sec) is the soil flow rate and Cp (Cal/mole,°C) is the soil heat
capacity. In addition to the Joule's heat, part of the power input is
consumed by electrolysis of water. This electrolysis power loss should be
subtracted from the total power to obtain a better estimate of the temperature
increase.
15
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Electrolysis
The voltage used in BSD greatly exceeds the potential required for
electrolysis of water. Therefore, during BSD, electrolysis occurs. Hydrogen
is liberated at the cathode and oxygen at the anode. The evolution of these
gases would induce a pH change at electrodes resulting from the presence of H+
and OH- ions. OH- combines with Na+ and similar ions present in the cake at
the cathode and passes through the filtrate or precipitate at the electrode.
This reaction causes the pH of the filtrate to become basic. For the opposite
reasons, the cake at the anode becomes acidic.
Generally the movement of the liquid or the particle occurs during
electroosmosis or electrophoresis. However, during electrolysis, the movement
of ions or complexing of ions occurs. It has been observed that generally the
ions' mobility is an order of magnitude larger than electro-osmotic velocity
and hence the total energy required to move the ion through the soil column
should be much less than electro-osmotic velocity.
(25)
According to Lageman of Geokinetics, the following factors play a key
role in determining the efficiency of the electrolysis process during heavy
metal decontamination of the soil. The factors are:
Nature of contaminant
Concentration of heavy metals
Soil type
Ionic radius
Solubility of contaminant as a function of pH
Ease of release of contaminant from the soil
• pH control around the electrodes.
ACOUSTIC PHENOMENA PRINCIPLES
An acoustic field is one in which the acoustic pressure and particle
velocity vary as a function of time and position. These pressure fluctuations
form a traveling wave, which propagates from the source throughout the medium.
Sinusoidal pressure fluctuations are characterized by their pressure amplitude
and frequency. A particle velocity is imparted to the medium by the action of
the pressure wave which also varies as a function of time, frequency, and
16
-------
position. Acoustic pressure and particle velocities are related through the
acoustic impedance of the medium.
The pressure fluctuations are the result of the transmission of
mechanical energy that can perform useful work to bring about desired effects
The type and magnitude of these effects depend on the medium. In acoustic
leaching, many of the forces that can contribute to the overall effectiveness
include:
• Ortho-kinetic forces, which cause small particles to agglomerate
BernouHi's force, which causes larger particles to agglomerate
Rectified Diffusion, which causes gas bubbles to grow inside
capillaries and thereby expel entrapped liquids
"Rectified" Stokes' force, which causes an apparent viscosity to
vary nonlinearly and forces the particle toward the source
Decreased Apparent Viscosity which may be due to high strain rates
in a thixotropic medium or localized heating which in turn lowers
both the viscosity and the driving force to move particles
Radiation Pressure is a static pressure which is a second-order
effect adding to the normal pressure differential.
A precise understanding of the relative significance of each of the
listed mechanisms or a given system/medium is unavailable. The contributions
to effective acoustic leaching are also dependent on the type of material
being treated since all the mechanisms listed depend on the physical/chemical
properties of the material under treatment. Therefore, it is difficult to
predict performance a priori, and experimental testing is needed to establish
baseline performance. A more thorough review is available in the two articles
by Ensminger and Muralidhara^ '
To introduce high-energy acoustic signals into the ground, one must
address the issues of elastic wave propagation in solids. The earth, for the
purposes of in-situ leaching, can be treated as a semi-infinite half space, in
which the earth's surface is the boundary of the half-space. It is well known
that a source acting normal to and on the surface not only produces acoustic
waves (more properly referred to as compression waves in this case) but two
additional waves as well. These are shear waves, where particle velocity is
perpendicular to the direction of propagation, and surface waves. Surface
waves exist at the boundary, extend a given depth into the medium, which is
17
-------
inversely proportional to the wavelength, and produce elliptical particle
motions.
Thus, the energy into the source is partitioned into these three types of
waves with roughly 10 percent going into compression, 25 percent into shear,
and 65 percent into surface waves. Likewise, as the signal propagates from
the source, the intensity of the compression and shear waves decrease as the
inverse of distance squared because they are propagating in the bulk of the
material. Since the surface waves propagate beneath the surface of the
material, their intensity decreases as the inverse of the square root of
distance. In addition, all three waves will be further reduced by soil
attenuation, which generally increases by the square of frequency. Therefore,
lower frequency waves will propagate (i.e., penetrate) much further. Buried
sources would produce mainly shear and compression waves. The relative
amounts depend on the design of the source.
Battelie's experimental work thus far has focused on acoustic
(compression) waves. Therefore, it is difficult to state how effective the
different wave types would be in leaching, but they may still be effective.
Note that the beneficial effects of decreased apparent viscosity may be
greatly improved with shear waves.
Another potential appliication of acoustics is for clearing the skin in
the recovery well. As more contaminant particles are driven to the recovery
well, the pores and interstitial spaces can become plugged. Beard and
Stulen^ ' have demonstrated that when acoustic energy is applied to plugged
glass frits or limestone specimens, five- to ten-fold increases in flow are
observed. This application of acoustics is mentioned here to demonstrate our
experience with producing wells. This effect is not part of the BSD
technology and is beyond the scope of this proposed work on BSD.
COMBINED ELECTRO-ACOUSTIC SEPARATION PRINCIPLES
Acoustics, when properly applied in conjunction with electro-separation
and water flow would enhance dewatering or leaching. The phenomena that
augment dewatering when using the combined technique are not fully understood.
18
-------
However, we have developed some hypotheses about possible mechanisms which can
be supported by experimental results.
It is theorized that, in the presence of a continuous liquid phase, the
acoustic phenomena (e.g., inertial and cavitation forces) that separate the
liquid from the solid into the continuum are facilitated by the electric field
and a pressure differential to enhance dewatering by means of one or more of
the electro-separation phenomena. There is also evidence of synergistic
effects of the combined approach. For example, free radical formation
phenomenon should aid electro-separation. In add it ion, as the cake is
densified (by sequestration and electro-osmosis), the liquid continuum would
be normally lost, but it is believed that, by chanelling on a macroscale,
acoustic energy delays the loss of the continuum, making additional dewatering
possible. It is the carefully executed combination of techniques to mutually
augment the overall solid/liquid separation process that is the essence of
Battelle's current BAD process. And because of this combined effect, BAD has
been found to be more effective than either electro-separation or acoustically
enhanced separation alone. The same effectiveness is expected for BSD.
Soil particles are generally colloidal in nature and the structure of the
soil particle may be indicated, as shown in Figure 3.
A.
B.
C.
D.
E.
Continuous capillary or pore
Closed capillary or pore
Chemisorbed surface
Contaminate between the two particles in a medium
Water molecules
Figure 3. Structure of Soil Particle
19
-------
Application of electric field will tend to mobilize the liquid present in
an open capillary such as A by electro-osmosis. Acoustic field has the
ability to pump out the liquid present in closed pores such as B by a
mechanism called rectified diffusion (discussed earlier in Section 3.2).
Application of acoustic field could also rearrange the particles, creating new
channels to assist electro-osmosis, as shown in Figure 4.
Before applying acoustics
(open-ended capillary closed)
After applying acoustics
(open-ended capillaries open)
Figure 4. Rearrangement of Particles from Application of Acoustic Field.
Rearrangement of particles by acoustic field opens up new capillaries, and
hence, electro-osmosis becomes more effective. It was postulated that
application of electro-acoustics in the presence of hydraulic gradient would
basically
Enhance co-transport of decane with movement of water because of ts
hydrophobic and light nature
Transport heavy metals by mere ion migration and electro-osmosis
20
-------
SECTION 3
PROJECT PLANNING
This project was conducted under the U.S. EPA's Emerging Technologies
Program, which is a part of the Superfund Innovative Technology Evaluation
Program. The project sponsored by the Risk Reduction Engineering Laboratory
under the above programs required a detail test plan that includes a quality
assurance project plan, material selection and characterization, and
experimental design. These items were discussed with the project officer as
part of the project planning, and the written document experimental design was
submitted to U.S. EPA prior to initiation of the study.
QUALITY ASSURANCE PROJECT PLAN
The initial requirement of this program was to develop a Quality
Assurance Project Plan (QAPP) that included the following items:
1. Project description and intended use of the data
2. Project organization and responsibilities
3. Personnel qualification
4. Procedures used to assess data quality
5. Quality assurance objectives for critical measurements
6. Experimental procedures
7. Critical test parameters and analytical procedures
8. Data collection, analysis, and reporting
9. Internal quality control checks
10. Performance and system audits
11. Project staffing and percent time on project
12. Schedule
13. Work plan
14. Analytical methods and operating procedures for instruments.
21
-------
The QAPP was approved by the U.S. EPA before initiating the experimental
studies.
MATERIAL SELECTION AND CHARACTERIZATION
Soil Types
Different types of soils contaminated with organics and inorganics at
superfund sites can range from highly permeable sandy soils to less- permeable
clays. The extent of chemical adsorption to clay is relatively high and
mobilization of these compounds from such soils is known to be difficult.
Therefore, we proposed to focus most of our efforts on contaminated clay soils
to test the applicability of the electric and acoustic fields for
decontamination.
The soils for the present study were either clay loam, sandy clay, silty
clay, or clay having over 40 percent clay content. Appropriate sources of
clay soil were located in Northern Ohio with the help of the U.S. Soil
Conservation Service. The soils were classified for their constituents and
characterized by particle-size analyses. Soil was also analyzed for organic
matter content. All of these analyses were performed by the Ohio Soil
Characterization Laboratory, Department of Agronomy, The Ohio State
University, Columbus, Ohio. The standard operating procedure for all the
analyses is briefly presented in Section 5.
Organic and Inorganic Contaminants
The potential applicability for BSD is expected to range from insoluble
organics (e.g., petroleum hydrocarbons and halogenated organic solvents) to
inorganics, such as heavy metals (Cr, Cd, Pb) and cyanide. For the screening
level studies, we proposed to use a relatively nonvolatile heavy hydrocarbon
(decane) and one heavy metal (zinc) as soil contaminants. Decane was selected
as the nonaqueous phase liquid because it is a constituent of petroleum
products and is used in a number of industries including organic synthesis,
jet fuel research, rubber, and paper. It is also used as a solvent. Zinc was
22
-------
selected for our inorganic species because it is one of the heavy metals that
is frequently a soil contaminant. Selection of zinc was also based on its low
toxicity and relative ease involved in handling, analysis, and disposal. If
the heavy metal removal was found to be effective with zinc, additional tests
with another metal (e.g., cadmium) would be conducted.
Electrical and Acoustical Properties
Prior to the work in the test unit, ranges of the basic electrical and
acoustical properties for a given sample preparation were determined. These
parameters include pH, electrical conductivity, acoustical impedance,
attenuation, and zeta potentials. These values are expected to be useful in
estimating initial parameters for use in the test cell. That is, the
intensity of the acoustic source, the placement of the electrodes relative to
the acoustic driver, the voltage, and the electrode spacing.
EXPERIMENTAL INVESTIGATION
Preparation of Soils
The clay soil obtained for the present study was mixed with decane to
yield a concentration of 8 weight percent (dry basis) or with zinc chloride
(ZnCl2) to yield 1 g of Zn per kilogram of soil (0.2 percent dry basis). For
additional tests with metals, it was planned that cadmium salts would be mixed
with zinc to yield 1 g/kg of Cd and 1 g/kg of Zn. The soil samples with the
respective contaminants were thoroughly mixed and four samples from different
locations were obtained to determine the uniformity of composition. Decane
analysis was performed by a gas chromatographic method, whereas the zinc
content was determined by atomic absorption spectroscopy (Section 5).
Bench-Scale Study with a Test Unit
A test unit was constructed as a simple modular design of stacked
sections to control the size of the test specimen. The internal dimensions of
23
-------
the test cell were chosen so as to generate acoustic plane waves into the soil
sample. A detailed description of this unit is given in Section 5.2.
Ifthe acoustic field is to treat the bulk of the soil in the ultimate
application, it is necessary to minimize attenuation. In most homogeneous
materials the attenuation increases as the square of frequency. Published
data on clays indicate that attenuation at 400 Hz is on the order of 1 to 2 dB
per foot, at 1000 Hz is 8 to 9 dB per foot and at 4000 Hz is 20 to 33 dB per
foot'37'. Therefore, it is clear that to obtain reasonable penetration, the
frequency must be kept under 500 Hz.
At 500 Hz, the wavelength in soil ranges from 3 to 6 in. The internal
dimension of the test unit must be less than half the wavelength to propagate
plane waves. Therefore, if the test unit is round, the inside diameter should
be 3 in. Longer wavelengths (i.e., lower frequencies) can then be
accommodated by the same test unit. The advantage of launching plane waves is
that the acoustic field will be uniform. That is, every treatment volume will
experience the same pressure fluctuations and particle displacements.
The electrodes to generate the electric field were placed in the test
cell at a given distance from the acoustic source. These were fabricated as a
sandwich with insulating standoffs used to set the interelectrode separation.
The electrodes themselves were fairly thin mesh screens to allow the acoustic
energy and liquid to pass.
The membranes are thin sheets of rubber on polymer. The purpose of the
top sheet was to enable the acoustic waves to pass through the sample without
carrying any product from the upper chamber. The purpose of the bottom sheet
was to collect the recovered product and enable the acoustic wave to pass on
through to the bottom chamber.
The test matrix was designed to evaluate combinations of key parameters
to determine recovery rate as a function of the electric and acoustic fields.
The test variables and their ranges are as follows:
Applied Voltage or Electrical Power--
The test was conducted for 3 different voltages or electrical power. One
voltage was used for duplicate runs. The control experiment was conducted at
0 v.
24
-------
Acoust i c Energy- -
The acoustical effects were investigated for 2 frequencies. It was
proposed to use one frequency ranging from 200-500 Hz and the other 1000-2000
Hz. A control experiment was conducted without any acoustical energy.
Mo isture Content - -
During the application of electric field, water in the soil will move
from the anode toward the cathode. This will cause the anode layer to become
dryer. Since water is the only transport medium for the contaminant, water
was introduced at the surface of the anode to maintain the moisture content of
the soil and ensure the transport of contaminant. The initial solids percent
for the decane contaminated soil was about 53 percent while the initial solids
percent for the zinc contaminated soil was about 62 percent.
Treatment Durat i on - -
The test was conducted for 3 or more durations. The leachate volume
collected at the effluent port was noted with time.
At the conclusion of each experiment, the soil samples and, if relevant,
leachate were analyzed for the respective contaminant. All of the analytical
work was performed in Zande Environmental Services, Columbus, Ohio. Some
samples were analyzed by U.S. EPA for quality assurance/quality control
purposes. The decane and zinc analytical methods are listed in Section 5.
ESD Tests on Decane--
The critical test parameters evaluated in this project are the following:
• Voltage (4 levels)
• Acoustic power (3 levels)
Acoustic frequency (1 level)
Volta e and acoustic
• Time 43 levels).
The experimental protocol is described below:
Step . Conducted experiments at 4 voltage levels. (0 V/in., 12.5
V/in., 25 V/in., 37.5 V/in.) (4 levels). These voltage levels were
chosen based on the conductivity of the suspension. Higher conductivity
25
-------
results in larger voltage, thereby causing excessive electrolysis and
internal heating of the suspensions.
Step 2. A second series of experiments was conducted with acoutstic power
input as a variable at 1 frequency, no electric was used . (0 w, 0.47 w,
and W at 400Hz) (3levels).
Step 3. Based on the results of Step 1, the best voltage conditions were
chosen and, based on Step 2, the best acoustic power setting was chosen,
and experiments were conducted at one particular frequency (3 tests).
Step 4. Based on results of Step 1, a series of experiments was
conducted with time as a variable. Some of these tests were electric
only and some were electric and acoustic.
ESD Tests on Zinc--
The critical test parameters evaluated in this project are the following:
Electric power (3 levels)
Acoustic power (3 levels)
Acoustic frequency (2 levels)
Time (3 levels).
The experimental protocol is described below:
Step 1. Conducted experiments at 3 power levels (0 W, 0.114 W, and 0.811
W) for 50 hours and no acoustic power.
Step 2. Based on the results of Step 1, the best electrical power
condition was chosen and experiments were conducted at three acoustic
power levels (0.44 W, 0.88 W and 1.302 W) and one particular frequency
(400 Hz).
Step 3. Based on the results from Step 2, the best acoustic power
condition was chosen, and an experiment was conducted at the second
frequency (850 Hz) .
26
-------
Step 4. Based on the results from Steps 1,2, and 3, experiments were
conducted for 3 times (25 hours, 50 hours and 100 hours).
27
-------
SECTION 4
EXPERIMENTAL INVESTIGATION
In this section of the report, details of material selection,
characterization, experimental setup, experimental procedure, and analytical
procedures are discussed. Details are provided below.
MATERIAL SELECTION AND CHARACTERIZATION
Ten 5-galIon containers of 60 percent clay soil were obtained from
Paulding, Ohio, with the assistance of the Soil Conservation Service. Table 3
presents the particle-size distribution of the as-received soil; The sand,
silt, and clay contents were 10.8 11.7, 27.2 29.0 and 61.05 59.3
percent, respectively. Based on the US Department of Agriculture textural
classification, the soil used in the present study falls into the category of
clay. The pH and organic carbon contents of the soil are given in Table 4.
The soils are acidic and have a pH of about 5.5. The organic carbon content
for this clay soil is 1.87 weight percent (dry basis).
Soil Preparation
From each of the ten received containers, 21 Ibs of wet soil (70 percent
solid) were dried and mixed together. The dried soil was grounded using an
Abbe Fitz mill with an opening of i in. screen. The ground soil was used for
decane and zinc soil preparation.
Decane Soil Preparation--
Sample of soil prepared by adding 8 weight percent (dry basis) decane in
the laboratory. It was found through our laboratory testing that the received
soil did not mix well with the decane. The soil appeared to have higher
affinity for decane than water. Hence, decane was mixed with the dry soil
28
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TABLE 3. PARTICLE-SIZE DISTRIBUTION OF SAMPLES OF THE SOIL
Particle-Size Distribution
<2 mm
Sand ( mm )
CS MS
2-1 1-0.5 0.5-0.25
0
0
0
0
.7 1.
.8 1
.8 2
.6 1
vcs
cs =
MS
FS =
VFS
TS
CSI
8 3.0
.9 2.8
.0 3.0
.8 2.8
= Very coarse
= Coarse sand
= Medium sand
= Fine sand
Silt (
FS
0.25-0.1
4.2
4.0
4.1
3.8
sand
= Very find sand
= Total sand
= Coarse silt
VFS
0.1-0.
1.6
1.8
1.7
1.9
MSI
FSI
TSI
cc
FC
TC
TS CSI
05 2-0.05 50-20
11.2 10.1
11.1 11.7
11.7 4.6
10.8 12.1
= Medium silt
= Fine silt
= Total silt
= Coarse clay
= Fine clay
= Total clay
MSI
20-5
5.6
4.7
9.1
4.2
urn
) Clay ( urn )
FSI
5-
11.
11.
15.
11.
2
8
2
3
0
TSI
50-2
27.5
27.5
29.0
27.2
CC FC TC
2-0.2 <0.2 <2
39.9 21.6 61.4
39.7 21.8 61.5
40.2 19.1 59.3
39.8 22.4 62.1
Text.
Class
Clay
Clay
Clay
Clay
29
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TABLE 4. SOIL CHAEACTERISTICS (Four Samples)
Organic
_ _
Sample Water 0.01 M Carbon (Wt. %)
(1:1) (1:2) Dry Basis
l 5.4 5.1 1.89
2 5.5 5.2 1.88
3 5.5 5.2 1.86
4 5.5 5.2 1.86
30
-------
first and then with water to provide a homogeneous soil decane mix. The dried
ground soil (15 Ib.) was mixed with 1.2 Ib. decane using a Sigma mixer for 1
hour. Further, the decane-soil mix was mixed with 12.27 Ib. of water for
another hour. iF-rveSjactnea •*«;"•« prepareu ffcVroWffiy^fc same pr-ocedure. The
five prepared batches were mixed and placed in a sealed aluminum pan and
stored in a cooler. Five samples were taken from the mixed decane soil and
sent to Zande Labs for analysis. The results are shown in Table 5. Although
it was intended to prepare 8 percent (weight, dry basis) decane, lab analysis
indicated an average of 5.14 weight percent (dry basis) was present in the
soil. Further discussion on initial decane concentration is provided in
results section.
Zinc Soil Preparation--
The soil sample was inorganically contaminated in the laboratory by
adding 0.2 percent of Zn (D.B.) into the soil in the form of ZnCl2 The dried
ground soil (15.44 Ib.) was mixed in a Sigma mixer for 1 hour with 11.6 Ib. of
0.55 percent ZnCl2 solution to provide a soil containing 0.2 percent Zn. The
prepared soil was transferred to an aluminum container and stored in a cooler.
Five soil-zinc samples were taken from the mixed zinc soil and sent to Zande
Laboratory for analysis. The results are shown in Table 6.
Zinc-CaafflTunT ioTi Preparat i on
A soil sample (4 Kg) was inorganically contaminated in the laboratory by
adding 0.096 percent Zn (D.B.) and 0.1 percent Cd (D.B.) into the soil. Dry
soil (15 Ib.) was first mixed in a Sigma mixer for 1 hour with 9.0 Ib. of
ZnCl2 solution to provide a soil containing 0.096 percent Zn. The moisture
content of the zinc-prepared soil was 37.5 percent. Then, 8.82 Ib. from the
above zinc-prepared soil was mixed with 0.86 Ib. of 1.05 percent CdCl2
solution to provide a soil containing 0.096 percent Zn, 0.1 percent Cd, and 57
percent solids. The prepared soil was mixed thoroughly and stored in a glass
beaker in a cooler. Two soil zinc/cadmium samples were taken from the above
prepared soil and sent to Zande and U.S. EPA for zinc and cadmium analysis.
The results are shown in Table 7.
31
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TABLE 5. INITIAL PERCENT DECANE CONTAMINATION IN SOIL
BEFORE BSD, REPORTED BY ZANDE LAB
First Decane Analysis
Sample
Dl
D2
D3
D4
D5
Sample
Solids (%)
53.12
53.48
53.00
53.18
53.01
Wet Basis
(%)
3.85
3.87
3.36
3.86
3.76
Dry Basis
(%)
7.25
7.25
6.35
7.25
7.10
Corrected Decane Analysis
Wet Basis
2.81
2.83
2.46
2.81
2.75
Dry Basis
5.30
5.29
4.64
5.29
5.18
53.16
3.74
7.04
2.73
5.14
32
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TABLE 6. INITIAL ZINC CONCENTRATION IN THE SOIL
REPORTED BY ZANDE
Zn (%),
Sol ids (%) Dry Basis
Z01 57.5 0.1720
Z02 58.0 0.1717
Z03 57.8 0.1795
Z04 58.0 0.1347
Z05 57.9 0.1847
57.9 0.17
-33
-------
TABLE 7. INITIAL ZINC AND CADMIUM CONCENTRATION
IN THE ZINC/CADMIUM SOIL
Zinc Concentration Cadmium Concentration
(mg/kg) dry soil (mg/kg) dry soil
Sample Zande EPA Zande EPA
Feed 1 1193 1064 976 866
Feed 2 1052 1064 965 873
Average = 1093 Average = 920
34
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TEST UNIT DESIGN AND INSTRUMENTATION
The design of the test unit was developed primarily to accommodate the
introduction and characterization of the acoustical energy. The test unit is
shown in Figure 5. The intent was to reasonably simulate the field conditions
under which the acoustics would be applied. That is, the design was to
simulate the earth as much as could be expected in a laboratory apparatus.
Relatively low frequencies (compared to Battelle's EAD work) were chosen
because lower frequencies are required to penetrate the earth an appreciable
distance. The unit was designed to generate plane-wave acoustics in which
points of constant phase form a plane. The direction of propagation is normal
to the plane.
This approach reduces the acoustics problem to a one-directional case.
In this case, the acoustic field can be characterized with sufficient accuracy
with a few point measurements. This is an equivalent situation to the
electric field formed by the two parallel-plate electrodes.
The acoustic instrumentation includes an acoustic shaker, a load cell, an
accelerometer, and two hydrophones. The acoustic source is an Unholtz-Dickie
Model 1 electro-magnetic shaker. This shaker is the source of the acoustic
excitation. It transmits a maximum force of 50 Ib. and operates between 10 Hz
and 10,000 Hz. A Sensotec 31/1432-08 load cell and a PCB-321A02 accelerometer
mounted on the acoustic piston assembly were used to measure the force and
acceleration levels. These levels were used to calculate the mechanical power
input to the system. Two B&K 8103 hydrophones were used to measure the
dynamic pressure above and below the test cell. Basically, hydrophone signals
indicate the extent of attenuation.
Acoustic data were acquired during testing with the four channel
analyzer. This was under computer control (computer not shown in Figure 6) to
automate acoustic data collection and storage. Two plots of typical acoustic
records that were acquired and stored are shown in Figures 7 and 8. The data
in Figure 7 are typical since the signed traces from the load cell,
accelerometer and two hydrophones appear as single-size waves at the drive
frequency. However, in Figure 8, the load cell and accelerometer signals have
significant harmonic content, indicating some nonlinear interaction between
35
-------
CO
00
CO
r,
ACOUSTIC DRIVE?
CO
r~t
ro
rH
&
I
ij.
c
c
MEMBRANE
(polymeric material }
C-y-
ir> I
tr> * ••'"
HYDROPHONE
rr
» -.
' V*
M.T-
1
•**•
ii
It
-*,
f
A.
V
c:
1
( -f^,,, |H
! *t
S
i
:A
r\ i
.-T7T=
!.<-..;
y
t
- r
.....r £
^"
C
i
/
-«*«
1
"i
SI
^"* AT
i «rr>T[_
* ,„.., «rtjy
: 3-3/8"
(
23
/ *" "™" LIOU
it}' PO
S.!
* - 3/4
i
m *nTi
it
i
ACOUSTIC HEAD
LIQUID SA1PL1NG
ELECTRODES
S.S. Scrtfin {TOO mesh)
WOOD BOX
SOIL
Figure 5. Schematic of Laboratory Test Unit.
36
-------
Shaker
Load Cell: F
Accelerometer: a
Piston, Area A
Hydrophone: p 1
(upstream)
Test Volume
Hydrophone: p2
(downstream)
Acoustic
Termination
Power
Amplifier
Function
Generator
Four
Channel
Analyzer
A -I
Signal
Amplifier
Figure 6. Test Unit and Acoustic Instrumentation.
37
-------
10
FORCE
NEWTONS
-10
40
ACCELERATION
G
40
10
PRESSURE
PASCALS
-10
10
PRESSURE, H2
PASCALS
10
TIME, SECONDS
IT 02
Figure 7. Typical Acoustic Signals Acquired During Testing.
40
FORCE
NEWTONS
-40
100
ACCELERATION
G
•100
20
PRESSURE
I'ASCAI.5
-20
4
PRESSURE, H2
PASCALS
TIVE Seocncfc
0.04
Figure 8. Signals Indicating Nonlinear Interaction
Between Drive Piston and Soil Column.
38
-------
the driving piston and the soil column. Note that the hydrophone signals
appear more as sine waves. This is attributed to the higher attenuation of
the harmonics as the acoustic signal propagates through the soil before
reaching the hydrophones.
Test Cell
Two test cells, 3-in. ID (internal diameter) 4.0 and 6.0 in. height made
of acrylic tubing, were used to hold the contaminated soil. The test cell
used for decane tests was different from those tests of the zinc cell. A
description of the two cells is provided below.
Decane Test Cell--
The test cell 3-in. internal diameter 4-in. height consists of two
electrodes, the anode on top and the cathode at the bottom. A schematic of
the decane cell is shown in Figure 9. The distance between the two electrodes
is 2 in., which essentially is the sample cake thickness. The anode is a 3-
in. diameter, 100 mesh stainless steel screen, whereas the cathode is a
perforated s.s supporting plate. The cathode is supported by four s.s. rods.
A leachate collecting chamber was placed under the cathode. Leachate from the
soil was drained through pipes to the leachate collecting pans.
Zinc Test Cell--
The test cell, 3 in. (internal diameter) x 6.0 in. (height) was designed
for the purpose of flushing to maintain the moisture content of the soil.
During the application of the electric field, electro-osmotic phenomena caused
the water to move from the anode toward the cathode. This water movement
would cause the layer in contact with the anode to become drier and thereby
causing less ion movement since water is the medium in which ions transport.
Since a medium is required to transport ions, the flushing design was devised.
More space was added to increase the distance between the anode and the
cathode and to create two electrode-flushing chambers. The anode-flushing
chamber is located at the top of the anode, whereas the cathode-flushing
chamber is located at the bottom of the cathode, where the leachate is
39
-------
RUBBER
GASKET
THERMOCOUPLE
TYPE (K)
ANODE (8)
9.S. ROD
SUPPORT FOR
SCREEN
CATHODE
S.S. SCREEN
DRAINING
RUBBER
GASKET
POLYETHYLENE THIN SHEET
LEACHATE COLLECTING
PAN
9. Side View of Testing €ei\ for Electraacaastic oViM
Decontamination Process Used for Decane Treatment.
-------
collected. The distance between the anode and the cathode used in the zinc
experiments is 4.5 in. The anode is a 3-in.-diameter perforated plate
containing 1-mm-diameter holes and is connected to a spring-like lead to allow
the anode to move with the cake and establish contact. The cathode is a 100-
mesh S.S. screen supported by an S.S. perforated plate containing 4 mm
diameter holes. Both screen and plate were supported by four S.S. rods, which
criss-crossed under the perforated plate, Schematic of the zinc cell is shown
in Figure 10.
EXPERIMENTAL PROCEDURES
The following experimental procedure is used in conducting the
experimental investigation on both zinc and decane soil.
Fill the bottom wood box with a known amount of saturated sand.
Bolt the lower acrylic tubing on top of the box with a rubber gasket
in between.
Fill the lower acrylic tubing with saturated sand. The sand must be
very wet and compacted to ensure acoustic coupling.
Place a polyethylene plastic and rubber gasket sheet on top of the
lower acrylic tubing.
Place the testing cell on top of the polyethylene plastic sheet and
bolt the cell to the lower acrylic tubing.
Fill the leachate collecting chamber with distilled water until
water starts to flow into the leachate collecting pans. During the
zinc tests, the leachate draining pipes were connected to a
peristaltic pump, which fed from a 500 ml beaker filled usually with
about 350-400 mL distilled water. Water level was always maintained
below the cathode during both decane and zinc tests.
Place a known quantity of contaminated soil in the test cell on top
of the cathode and leachate collecting chamber.
Place the anode on top of the soil and exit connecting wire outside
the cell.
For the zinc tests the upper part of the test cell was modified for
flushing purposes (Figure 5). The modification created a chamber
above the anode which holds recycled water. The inlet tubing to the
chamber is connected to a peristaltic pump, which feeds and recycles
from a 500 mL beaker filled with about 350-400 deionized water.
Place a polyethylene plastic and rubber gasket on top of the test
cell, so that sand at field capacity of 9 percent moisture was
always in contact with the anode.
41
-------
POLYETHYLENE THIN
SHEET
OUTLET
FLUSHING SOLUTION
(RECYCLED BACK TO INLET)^
THERMOCOUPLE*
TYPE (K)
S.S ROD
SUPPORT FOR
SCREEN
DRAINING
PIPE
LEACHATE
OUTLET
ANODE FLUSHING
CHAMBER
INLET
FLUSHING SOLUTION
(RECYCLED)
ANODE (B)
S.S. SCREEtf
CATHODE
S.S. SCREEN
100 MESH
RUBBER
GASKET
POLYETHYLENE THIN SHEET
LEACHATE
COLLECTING
CHAMBER
Figure 10. Side View of Testing Cell for Electroacoustic Soil Decontamination
Process Used for Zinc Soils Zinc/Cadmium Soil
-------
Bolt the upper acrylic tubing to the test cell.
Fill the top acrylic tubing with wet sand.
Connect the acoustic head to the acoustic driver (the acoustic head
should be in contact with the sand) .
Insert the thermocouple inside the testing cell.
Set the appropriate power input, acoustic power, and frequency and
conduct the test for a given interval of time.
During the test, the following variables were monitored: voltage,
current, cake temperature, acoustic force, and acoustic
acceleration.
• At the end of the test, turn off all the power sources.
Weigh the treated cake and liquid leachate (zinc anode liquid and
zinc cathode liquid).
Save both leachate and cake in glass jar with Teflon seal ing.
Quarter and cone the samples in case of decane. In caseof zinc,
dry the sample at 105 C and 1 in. Hg for 24 hours, grind, and mix
the sample.
Send samples for analysis.
ANALYTICAL PROCEDURES
All the chemical analyses were performed according to the methods
recommended in Test Methods for Evaluating Solid Waste, SW 846 (U.S. EPA,
1986). The atomic absorption spectroscopic method (flame AA - direct
aspiration) was used to analyze zinc and cadmium. The zinc concentrations in
leachate and soil were determined using Method 7950. Cadmium in leachate and
soil was analyzed by Method 7130. For sample preparation, Method 3010 was
used with leachate and Method 3050 with soils. The samples were digested
using nitric acid, hydrochloric acid, and hydrogen peroxide. The analyses
were performed on Perkin-Elmer Model 5000AA using an oxidizing air/acetylene
f 1 ame.
Decane analyses were performed using gas chromatographic methods.
Soxhlet extraction procedure (Method 3540 in SW 846) was used in the sample
preparation and during extraction of decane from the soil. Here, v/vmix
of pesticide-grade hexane and acetone was used as the extraction solution.
Extracts were concentrated using the standard Kuderna Danish apparatus. The
43
-------
analyses were performed on a Hewlett-Packard Model 5890A gas chromatograph by
flame ionization detection. The column used was Supelco SPB-5, 30 m long, 0.5
mm ID, and 1.5 ppm phase thickness. The temperature program was 100 C
initially and ramped at 10 C/min without initial hold. Once the temperature
reached 250 C, it was held for 10 min. The injector and detector temperatures
were 230 and 250 C, respectively. Carrier gas and flame ionization detector
make up gas were nitrogen. Combustion support gases were air and hydrogen.
Sample injection volume was 1 ml and was performed by an HP Model 7673
autoinjector. Data were collected by an HP Model 3396 integrator.
All the chemical analyses were performed by Zande Environmental
Laboratories, Columbus, Ohio. For quality-control purposes, some samples from
the same batch were sent to the U.S. EPA's Risk Reduction Engineering
Laboratory for chemical analyses.
The soil samples were analyzed for particle-size distribution, as
recommended by V. J. Kilmer and L. T. Alexander (1949, Methods of Making
Mechanical Analyses of Soiis. Soii Science 68:15-24). Each soii sample was
dispersed in a sodium hexametaphosphate and sodium carbonate solution. The
<20 p, <5 fl, and <2 p fractions were determined by pipetting after
sedimentation. The <0.2 p fraction was determined by pipetting after
centrifugation. Sand was separated from silt and clay by washing the sample
through a 300-mesh sieve. The various sand fractions were determined by dry
sieving and weighing.
Organic carbon content in soil was determined by the dry-combustion
method. This involved combusting approximately 2 gal. of soil at 900-950 C in
oxygen gas stream. Carbon dioxide generated was absorbed by ascarite bulb.
The organic carbon content in soil was estimated from the amount of C02
generated.
44
-------
SECTION 5
EXPERIMENTAL RESULTS
Batch experimental results for both decane and zinc are discussed below.
The following BSD parameters were investigated.
Effect of electric field on decane mobility
Effect of voltage and time on decane removal
Effect of acoustic power and frequency.
DECANE EXPERIMENTAL RESULTS
A total of 30 decane tests were conducted to establish the technical
feasibility for decane removal via BSD. Tests 1 through 9 were shake-down
tests. For Tests 10 through 25, the treated soil samples were mixed
thoroughly and sent for analysis to both labs. These tests were desiigned to
monitor the decane removal. Results are shown in Appendix A. Tests 26
through 30 were designed to monitor the decane mobility and removal. The
treated soil samples for each test were divided into three layers (F igure 11)
Then each layer was quartered as shown in Figure 12. Two quarters were sent
to the U.S. EPA laboratory and the other two quarters were sent to Zande
Laboratory.
Initial Decane Concentration
The soil sample was contaminated at Battelle by adding 8 weight percent
decane, dry basis (D.B.) into the soil. However, since the soil favors the
absorption of water over decane and since the soil was saturated with water,
all of the 8 percent did not go into the soil. Five soil-decane samples were
taken from the mixture for laboratory analysis. Soil analysis by Zande Labs,
Columbus, Ohio, showed an average of 5.14 percent (D.B.) present in the soil.
However, Test 15 (control no BSD) soil shows 6.42 percent decane for the
45
-------
Cathode (-)
J o,.
Section A
1 0.5"
Section B
J 0.5"
Section C
Figure Side "View"of the Treated ESD Cake Decane Tests
(26D, 270 28D and 300} Showing the Three
Analyzed Layers
Figure Top View Decane .ayer Showing How the
Layer Was Divided ana Analyzed
-------
same mixed soil analyzed by the same laboratory. This discrepancy in the
initial decane concentration in the soil made subsequent data analysis very
difficult. Test Sample 15D (control) was analyzed by both Zande Labs and the
U.S. EPA Laboratory. The analytical results were 6.36 and 6.48, respectively,
Since the laboratory analysis on decane concentration for Test 15 match the
U.S. EPA decane analysis, it was decided to take the Test 15 decane
concentration as the reference for initial decane concentration in the soil.
Table 5 shows Zande Labs data for initial decane concentration in the soil
before correction and after correction. The initial solids content of the
decane soil was 52.8 percent.
Effect of Electric Field on Decane Mobility
When a d.c. electric field is imposed against a porous soil medium,
migration of water occurs toward the cathode. This phenomenon, called
electro-osmosis, refers to the migration of ions that have the ability to
compensate the charges on the soil toward the opposite charged electrodes.
Water is transported during this phenomenon by ions because of viscous
interactions, water of hydration, and molecular collisions. We hypothesized
that, since decane is hydrophobic and lighter than water, the decane would co-
transport with water during electro-osmotic transport. However, our
experimental results do not completely validate this theory. However, as
shown in Table 8, results of Tests 26 through 30 indicate that there seems to
be a trend for the movement of the decane from the top anode layer toward the
cathode layer and the movement of water is also in the same direction. Thus,
the results indicate that there is a potential for the transport of organics
in aqueous suspensions in the presence of d.c. electric fields. This effect
can possibly be further enhanced by using appropriate additives, such as
dispersants used in tertiary oil recovery by the petroleum industry.
Effect of Electric Field and Time on Decane Removal
The following electrical and time parameters were investigated:
• Voltage (0, 12.5, 25, 37.5, V/in.)
Time 1.25, 2, 24.0 hours).
47
-------
TABLE 8. EFFECT OF ELECTRIC FIELD ON THE DECANE MOBILITY
Acoustic EPA Decane % Decane Removal
Test Voltage Power (%) Layer A Layer ()
No. volts/in. Watts layer Wet Basis Layer A x
26 -37.5 0 Layer A 4.45 0
Layer B 4.3 3.49
Layer C 3.9 12.36
27 45 0 Layer A 4.35 0
Layer B 4.17 4.16
Layer C 3.56 18.16
28-25 0 Layer A 4.29 0
Layer B 4.07 5.13
Layer C 3.34 22.14
30 -37.5 0 Layer A 4.44 0
Layer B 3.90 12.16
Layer C 3.54 20.27
48
-------
The analytical results for decane tests were inconsistent. Zande Lab analyses
for decane concentration in soil samples were higher than those of the U.S.
U.S. EPA. This inconsistency made it difficult to reach a firm conclusion
about the percent decane removal resulting from the electric field on BSD and
time. However, based on the tests (140, 15D, 170, 21D, 22D, and 230) in which
the decane values from the two labs were relatively close, the data indicated
about 10-25 percent decane removal. For example, Test 15D (control test, no
BSD) showed an average 6.42 percent decane in the soil, whereas Test 17D (in
which the electric field/acoustic was applied at 12.5 V/in. , 0.6 W, 2 hour)
showed a decane removal of 20.25 percent (from Zande) to 25.7 percent (from
U.S. EPA Laboratories). The average of the two analyses is 22.9 percent
decane removal. Since most of the tests were done for a short time (less than
25 hours), one expects a larger decane removal if BSD were applied for longer
periods with the flushing and added dispersant. However, more tests are
needed to validate the above assumption.
Effect of Electric Field on Soil Moisture Content
The electro-kinetic potential across the soil is the driving force of
electro-osmotic dewatering. As discussed previously, water moves from the
anode toward the cathode. This movement of water causes the moisture content
of the soil to change. The layer in contact with anode is always drier. This
phenomena can be seen clearly for the decane soil Tests 26D, 27D, 28D, and
300. For example, in Test 27, the cake in contact with anode had a moisture
content of 27.35 percent, the cake between the anode cake and the cathode cake
had a moisture content of 38.76 percent, and the cake in contact with cathode
had moisture content of 49.42 percent. The initial moisture content for the
soil before BSD treatment was 47.32 percent. Figure 13 shows cake moisture as
a function of cake gradient.
Effect of Acoustic Field
The analytical results for the decane tests had high variability, as
mentioned earlier. Therefore, the effectiveness of the electric fields with
49
-------
Anode (+)
Cathode (-)
27.35
38.76
49.42
Figure 13. Side View of Decane-Treated BSD Cake
Showing Layer Moisture Content.
50
-------
or without an acoustic field is difficult to accurately detect. The highest
estimate of removal is 30 percent. Acoustics has always been applied as an
enhancement to electric field in which the rate of removal is increased with
some increase of overall removal. But, because of the low removal rate of the
electric field and high variability of the analytical results, and the fact
that no rate information was obtained, no acoustical effects can be observed.
This is not to say there is no acoustic effect; there indeed may be a
positive effect, but it cannot be "observed" in the relatively few number of
tests with highly variable results.
Statistical Analysis on Tests 26D-30D
A statistical analysis was performed on Tests 26 D-30D laboratory result
from both U.S. EPA and Zande Lab. Analysis shows that there doesn't appear to
be any relationship between the decane concentration measured by the two
laboratories. The correlation between the 15 measurements made between the
two laboratories was calculated to be 0.233. A correlation of zero would
indicate that there is no linear relationship between the two measurements,
whereas a correlation of 1 or -1 would indicate that there is a perfect linear
relationship between the two sets of measurements. The sample correlation of
0.233 was not statistically significantly different from zero; thus, there is
no relation between the two laboratories' data. Moreover, a statistical
comparison of the decane concentration measured by the two laboratories shows
that the measurements made by Zande tend to be an average 2.94 percent higher
than the measurements made by the U.S. EPA.
The 95 percent confidence interval for the average difference in the
measured decane concentrations ranges from 2.35 to 3.53 percent. This means
that we are 95 percent confident that individual differences between U.S. EPA
and Zande measurement fall between a minimum difference of 2.35 and a maximum
difference of 3.53 percent. Table 9 shows statistical regression output for
each test and an overall regression output on all the measurement points in
Test 26 through Test 30. The statistical output (standard error of estimate,
number of points used, standard error of coefficient, and root mean squared)
show a very poor correlation between U.S. EPA and Zande data. For example,
51
-------
TABLE 9. STATISTICAL ANALYSIS RESULTS FOR DECANE TESTS
Decane Results
Test Number
26DA
26DA1
26DA2
26DB
26DC
27DA
27D8
27DC
28DA
28DA
283B
283C
EPA (%)
5
5
6
6
6
5
6
7
6
6
6
5
.38
.29
.04
.07
.29
.99
.81
.04
.10
.10
.20
.58
Zande (%) Statistical Regression Output
9
8
7
8
8
8
8
11
8
10
7
10
.11
.89
.90
.40
.92
.91
.51
.64
.43
.31
.59
.49
26D Regression
Constant
Std Err of Y Est
R Squared (Adj , Raw)
No. of Observations
Degrees of Freedom
Coef f icient (s)
Std Err of Coef.
27D Regression
Constant
Std Err of Y Est
R Squared (Adj , Raw)
No. of Observations
Degrees of Freedom
Coefficient(s) 1
Std Err of Coef. 2
output :
- .019976
.530103
5521724
output :
.333129
.785111
.523948
11.72677
.4968266
.2350181
5
3
-2.11666
1.972165
.3334356
3
1
28D Regression output:
Constant
Std Err of Y Est
R Squared (Adj , Raw)
No. of Observations
Degrees of Freedom
Coefficient(s) -3
Std Err of Coef. 2
.2280125
.50094
.549209
30.18886
1.248483
4
2
52
-------
1-ABLE 9. (CONTINUED)
Decane Results
Test Number EPA (%) Zande (%)
Statistical Regression Output
30DA
30DB
30DC
6.02
5.73
5.77
8.27
8.73
8.36
300
Constant
Std Err of
Regression
Y Est
output :
-15.17859
.2439200
R Squared (Adj, Raw)
No: of Observations
Degrees of Freedom
.0346422
Coefficient(s)
Std Err of Coef.
-1.15202
1.112784
.5173211
3
MEAN
S.D.
6.03
.45
8.96
1.04
Regress i on output:
OVL DRY
Constant
Std Err of Y Est
R Squared (Adj, Raw)
No. of Observations
Degrees of Freedom
-.018986
Coefficient(s) .5307563
Std Err of Coef. .6173460
5.764438
1.081622
.0537989
15
13
Regress i on output:
26DA
Constant
Std Err of Y Est
R Squared (Adj, Raw)
.8587125
10.86250
.1539435
.9293563
53
-------
0.0537 root squared (raw) for the overall data shown at the end of Table 8
indicate that only 5.37 percent of the data fit the correlation. The
difference between the U.S. EPA measurements and Zande measurements and their
descriptive statistics are contained in Table 10. Also, Figure 14 shows Zande
measurements against U.S. EPA measurements.
PC Assurance of Analytical Data: Decane
All the analytical data for decane in soil samples used in the BSD
tests are given in Table 11. It is apparent that the analytical results were
inconsistent for the two laboratories. For example, the variation of
interlaboratory results ranged from 0.62 to 64.71 percent. However, the
quality control tests performed by both laboratories indicate significant
precision and accuracy of their data. For example, Sample 26DA was analyied
in triplicate by both laboratories (see Table 10). Percent variations were
»8.5 and »5 for U.S. EPA and Zande Laboratories, respectively. Recovery data
given in Table 12 show that the average percent recoveries were within 75 to
125 percent. Because of these conditions, it is difficult to determine the
inaccuracies in analytical results. The differences in interlaboratory
analytical results may be attributed to oversaturation of samples with decane,
nonuniformity of sample, incomplete mixing, and differences in laboratory
analytical execution. Consequently, it was decided to use only the analytical
data that have interlaboratory variations of less than 15 percent to determine
the effectiveness the ESD process is in decane removal.
It is recommended that further investigations be conducted by U.S. EPA to
improve the analytical methodologies for organic contaminants in soil samples.
Inconsistencies in analytical results as indicated in our study can have a
significant impact in the development of innovative treatment processes and
improvement of existing treatment technologies.
54
-------
1-ABLE 10. EPA AND ZANDE MEASURED DECANE CONCENTRATIONS
AND THEIR DIFFERENCES IN SOIL (DRY BASIS)
Test Number
26DA
2 6 DAI
26DA2
26DB
26DC
27DA
27DB
27DC
28DA
28DA
28D8
28DC
SODA
30DB
30DC
Number of
Samples
Minimum
Maximum
Mean
Standard Dev
EPA
(%)
5.380
5.290
6.040
6.070
6.290
5.990
6.810
7.040
6.100
6.100
6.200
5.580
6.020
5.730
5.770
15
5.290
7.040
6.027
0.468
Zande
(%)
9.110
8.890
7.900
8.400
8.920
8.910
8.510
11.640
8.430
10.310
7.590
10.490
8.270
8.730
8.360
15
7.590
11.640
8.964
1.071
Difference
(%)
3.730
3.600
1.860
2.330
2.630
2.920
1.700
4.600
2.330
4.210
1.390
4.910
2.250
3.000
2.590
15
1.390
4.910
2.937
1.064
55
-------
12.0
11.5
11.0
10.5
10.0
9.5
0.0
0.5
8.0
7.5
7.0
6.5
0.0
5.5
5.0
1
5.0
*
*
**
5.5
0.0
0.5
7.0
7.5
EPA
FIGURE 14. Zande Measured Decane Concentration Plotted Versus U.S EPA Measured Concentration-
-------
TABLE 11. COMPARATIVE ANALYTICAL DETERMINATION OF DECANE
IN SOILS BY U.S. EPA AND ZANDE LABORATORIES
Test
No.
10D
11D
12D
13D
14D
15D
17D
19D
20D
21D
22D
23D
26DA*
26D
26DC
27DA
27DB
27DC
28DA
28DB
28DC
SODA
30DB
30DC
EPA Decane
Concentration
Dry Basis
1.17
4.23
2.77
4.79
4.78
6.48
4.77
4.93
4.98
5.6
5.28
6.22
5.57
6.07
6.29
5.99
6.81
7.04
6.10
6.20
5.58
6.02
5.13
5.77
Zande Decane
Concentration
Dry Basis
5.46
5.59
5.14
5.08
5.63
6.36
5.12
3.75
3.57
6.1
6.75
6.58
8.64
8.40
8.90
8.91
8.51
11.64
9.37
7.60
10.49
a.27
a.73
8.36
Percent Variability
Zande and U.S. EPA
64.71
13.85
29.96
2.94
8.17
0.62
3.54
13.59
16.49
4.27
12.22
2.81
21.60
16.10
17.18
19.53
11.09
24.63
21.14
10.14
30.55
15.75
25.97
la.33
"For example, percent variability was calculated as follows:
For 10D 5.46 -1.17' 1Q() = 647%
O.4b + L.Li
57
-------
TABLE 12.QC DATA FOR EPA ANALYSES
Amount Spike Amount Spike Percent
Sample ID Added (ppg) Removed (ppg) Recovery
14D 10,000 7,700 77
10,000 7,300 73 (duplicate]
19D 200,000 202,000 101
200,000 165,200 82.6 (duplicate)
58
-------
ZINC TESTS
Results of zinc tests, background on electro-chemical reactions of zinc
at electrode and other related discussion is presented in the following
paragraphs.
Results of Zinc Tests
A total of 16 tests were conducted on the zinc-contaminated soil.
Results of these tests are shown in Appendix B. The first six tests (IZ-6Z)
were conducted to establish the standard procedures, such as flushing or
sectioning; for example, no sectioning was used in Tests 3-4.
The treated soil was mixed (cake in contact with anode was mixed with
cake in contact with cathode) and sent for lab analysis. Lab analysis did not
show any zinc removal. However, in Tests 5-6, the treated cake was divided in
half (cake in contact with anode and cake in contact with cathode). Results
show that over 80 percent average removal of the zinc was achieved in the
anode layer and some zinc accumulation in the cathode cake.
Backsround on Electra-chemical Reactions
of Zinc at the Electrode
During the application of d.c. electric field, electrolysis of water in
the soil occurs with the following reaction H20 A H+ + OH". The (OH) ions at
the cathode combine with cations to form appropriate compounds based on their
relative concentrations. Simultaneously, the pH at the cathode increases.
The zinc accumulation around the cathode is due to an increase in the soil pH.
Zinc is soluble at pH below 6. Above pH 6, zinc would exist as Zn(OH)2
ZnOH+, ZnOHCl, and Zn02, which are insoluble in water. Since the soil around
the cathode is basic (pH value of 9-11), the zinc will precipitate in the
layer around the cathode. Figure 15 shows the solubility of zinc as a
function of pH. The diagram shows zinc ion Zn+ become insoluble at pH
between 8-9. Also, we have calculated the percentage of zinc ions and their
complex forms at different pH. The calculations were performed using the
geochemical computer code MINTEQA2 (developed for U.S. EPA, 1988). The code
calculates the distribution of chemical species (ions, neutral species, and
59
-------
Figure 15.
The Amphoteric Nature of ZnO 1s Revealed In the Variety
and Solubility of the Ionic Species, which the Oxide
Displays on Dissolving 1n Water at Various pH
60
-------
ion-pairs) in a water system for total analytical concentration, pH, and Eh
data. In addition, the code may be used to compute in detail the changes in
fluid composition, the identity and the extent of precipitation or dissolution
of secondary minerals. Table 13 shows calculation for percent distribution at
pH 6 and 9.7. A more detailed analysis is listed in Appendix C. Since there
was zinc accumulation in the cake toward the cathode, it was decided to divide
the BSD treated soil into the following four sections:
• ZA - Soil in contact with anode (1 in. thick)
ZD - Soil in contact with anode layer (1 in. thick)
zc - Soil in contact with cathode layer (1 in. thick)
ZB - Soil in contact with cathode (1 in. thick)
A schematic of the four sections is shown in Figure 16. Also, it was observed
in Test 3 and 4 that the moisture content of the layer in contact with anode
was always decreasing, thereby, reducing the ion transport efficiency. Hence,
it was decided to modify the test cell so the anode layer can be flushed with
water to maintain its moisture consistency and, thus, to provide a transport
medium for the zinc ions. A schematic of the modified cell is shown in Figure
10.
The following BSD parameters were investigated:
• Leaching time
• Electrical power
Acoustic power
Acoustic frequency.
A mass balance on Test 16Z is shown in Table 14. Mass balance data show that
all of the zinc was accounted for. Initial zinc weight in the soil (before
BSD) is 0.818 g whereas total zinc weight in cake layers and leachate after
BSD totaled 0.819 g. No zinc was lost, which correlates well between
experimental and analytical data for that test. Only Test 16Z leachate was
sent for analysis. Other tests mass balance might show loss resulting from
analytical variation.
Effect of Time on Zinc Removal
The BSD time is one of the critical parameters for the zinc ion removal.
Figure 17 shows percent zinc removed as a function of cake gradient for 25 and
100 hours at power input of 0.510 and 0.390 W, respectively. The data shows
61
-------
TABLE 13. PERCENT IONIC DISTRIBUTION FOR ZnCl2
AT PH 6 AND 7
oH6
oH 7
Percent Distribution
Zn+2
cr
H20
u+l
94.0 Zn+2
5.7ZnCl +
96.7 Cl'1
3.1 ZnCl+
48.9 ZnOHCl
50.1 ZnOH+
48.9 ZnOHCl
50.1 ZnOH+
73.9 Zn(OH),
25.3 Zn(OH)3-
99.9 Cl
-i
1.5 OH-
64.2 Zn(OH),
33.0 Zn(OH)3-
1.2 Zn(OH)4
15.25 ZnOHCl
17.83 OH'
13.42 ZnOH+
17.83 Zn(OH)2
17.83 (OH)
17.83 Zn(OH)4-2
62
-------
Gradient
Anode (+)
Cathode (-)
Layer in Contact with Anode
ZA
Layer in Contact with Anode Layer
ZD
Layer in Contact
with Cathode Layer
Layer in Contact with Cathode
ZB
Cake After BSD
Process
(4 "-4.5" thickness)
J
Figure 16. Schematic of the Cake-Divided
Sections for Test 7Z-16Z.
63
-------
TABLE 14. SAMPLE MASS BALANCE AROUND THE ZINC FOR TEST #16Z
Cake Before BSD
Cake After BSD
Grains Dry Soil
485.52
Grains Zinc
0.8181
Anode (+]
0
1
BSD
2
3
4
Grams Dry Soil
114.49
Grains Zinc
0.0266
Grams Dry Soil
123.39
Grains Zinc
0 .03977
Grains Dry Soil
127.36
Grains Zinc
0 .06729
Grans Dry Soil
119.68
Grams Zinc
1.628
Cathode (-)
Percent
Zinc Removed
100
-68.63
Accumulated
211.5
Zinc weight in leachate = 0.0577 g
Mass Balance Around the Zinc
Initial zinc concentration in the soil = 0.001685 g zinc/g dry soil
Zinc weight in the soil before BSD = 485.52 x 0.001685
= 0.818 g
Zinc weight in the cake after BSD = (114.49) (0.0002325) + (123.39)
(0.0003223) + (127.30) (0.0005286)
(119.68) (0.005248)
= 0.02662 + 0.03977 + 0.06729 + 0.62808
= 0.76176
Zinc weight in the leachate after BSD = 0.0577 g
Total zinc weight after BSD = Zinc weight in the soil and zinc weight in
leachate.
= 0.76176 + 0.0577
= 0.819 g
64
-------
o
X
X
txl
O
c
r-j
c
O
O)
DC
o
c
•I—
IVI
-------
the longer the BSD time, the higher the zinc removal in all layers except the
layer adjacent to the cathode. For example, in cake gradient 1, at 100 hours,
there was 86.2 percent zinc ion removal, whereas at 25 hours in the same layer
under similar experimental conditions, zinc ion removal was 63 percent.
In cake gradient 2 at 100 hours, the percent zinc removal was 80.87,
whereas at 25 hours, the percent zinc removal was only 4.5 percent. Table 15
shows a schematic of comparative actual concentrations of zinc ions in each
cake gradient. During the 25-hour run , approximately 1063 ppm of zinc was
transported across the cake length. However, during the 100-hour run, the
total amount of zinc transported was 1485 ppm. This suggests that it took 75
hours to transport the extra 322 ppm from cake gradient number 1. From the
figure, it can be inferred that the transfer efficiency of ions decreases with
increasing time. This perhaps may be due to dynamic changes in the
concentration of those ions in that particular cake gradient. Conventional
techniques such as pump and treat normally require 2-3 years for an acceptable
cleanup period in a sandy soil Treatment time of 100 hours to reduce the
concentration levels to less than 85 percent by BSD appears extremely
beneficial.
Effect of Average Power on Zinc Removal
As discussed earlier in the decane section, electro-kinetic potential
across the contaminated soil is the driving force for electro-osmotic rate.
The current that is created by this potential is a function of electro-kinetic
property of the material, such as conductivity and pH. Both current and
voltages have a significant effect on zinc ion removal. Data in Figure 18
show the higher average power consumed, the more zinc was removed in each
layer at constant BSD time at cake gradient 1 and 50 hour BSD (one inch from
the anode). A total of 89.73 percent zinc was removed at an average consumed
power of 0.811 W whereas at 0.114 Watts, 60.18 percent of the zinc was
removed, and, at 0.013 W, 30.25 percent zinc was removed. Moreover, the data
clearly indicate that zinc ions are accumulating at the cathode because of the
high alkalinity of the soil (pH 9-11). Figure 19 shows actual zinc
concentration as a function of cake gradient at three average powers for 50-
hour tests. For the 100-hour tests, much higher zinc removal was achieved at
a power of 1.423 W than at power of 0.390. However, the efficiency (kW/equiv.
66
-------
TABLE 15. ZINC CONCENTRATION AT DIFFERENT CAKE
GRADIENT FOR DIFFERENT LEACHING TIME
Electric Time (hours)
0 Anode (+)
1
2
3
4 Cathode (-)
0
1685
1685
1685
1685
25
Zinc
622
1608
1471
2965
50
Concentration (ppm)
166
585
1858
4513
100
232
322
528
5250
-------
•o
O)
Ol
ce
O
D-
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
Anode (+)
Figure 18.
control No ESD (0 watts)
— T f j ._
1 2 3
CAKE GRADIENT, INCH
Variation of Zinc (Wt%) Removed/Accumulated as a Function
of Cake Gradient for 0, 0.013, 0.144, and 0.811 Average
Power Input for 50 Hours' Leaching Time.
Cathode (-)
-------
en
ID
10
Figure 19. Variation of Zinc Concentration as a Function of Cake
Gradient at 0.013, 0.144, and 0.869 W Power Input
for 50 Hours' Leaching lime.
-------
ion) of removal was better at a low power that at high power. Figure 20 shows
percent zinc removal for 100-hour tests.
Effect of Acoustic Power and Frequency on Zinc Removal
The data from the zinc results was processed to determine the average
input power into the soil column. First, the power was determined at the
sample points acquired during the test. A typical result is shown in Figure
21. The results are fairly constant up to record number 50. At that point, a
slightly lower power is being impressed on the column. This change is due to
the need to periodically add more soil to the top chamber as consolidation
occurs. The sample powers were averaged to obtain the overall average input
power for the test. These are the values that appear in the table of results.
The data from the zinc tests appropriate for the evaluation of the
acoustic effect is shown in Table 16. The results from five tests are
included along with the parameters that describe the test. Four zinc
concentrations are shown for each test. These are the values in the four
layers taken from each sample after the test.
The data from the three tests with acoustics, Test 12Z, 14Z, and 15Z, is
compared to the control test of 11. The results are compared for each layer.
Layer 4 is not considered because the method of zinc removal at the cathode
had changed between the control, Test 11, and the acoustic tests. This
allowed a total of 9 removal rates to be calculated, which are attributed to
the addition of the acoustic fields.
The most interesting and encouraging results are obtained for Layer 3.
For the two cases with frequency of 400 Hz and power levels of 0.44 and 0.86
W, there is an additional removal of 17 percent. Even if the estimate of the
concentration of the control was estimated low by 100 rag/kg and the
concentration of the acoustic tests were high by 100 rag/kg, the removal would
still be 6 percent.
The results from Layer No. 1 are inconclusive. The numbers are all very
low and similar. They only differ by a maximum of 50 mg/kg, which is on the
order of the accuracy of the analytical methods. Therefore, there is no
statistically significant difference.
70
-------
ct:
vj
Q.,
50
Anode (+)
gurc 20
Cake gradient Inch
tion
1 432
if Z
and
-
Ranoved Ht%] as; unction
.390 M for 100 Hours Leachiny IK
ad wt
-------
TEST 14Z
CO
o
LU
^
o
Q_
0.9
0.8 -
0.7
0.6 H
0.5
0.4
0.3
0.2
0.1
0
0
20 40
RECORD NUMBER
Figure 21. Acoustic Input Power Versus Record Number.
60
-------
TABLE 16. ACOUSTIC DATA FOR ZINC EXPERIMENTS
Test Number
Ave. Electrical power (ff)
Voltage Field (V/in.) 1
Treatment Time (hours)
pH Leaching
pH Leachate
Frequency (Hz)
Power (W)
Zinc Concentrations (mg/kg)
Layer 1
Layer 2
Layer 3
Layer 4
Additional Removal with Acoustics
w.r.t. Test 7Z
Layer 1
Layer 2
Layer 3
Layer 4
7Z
0.869
.4 4.3
50
3.56
11.65
0*
0*
180
687
1847
5644
- + -
__.
—
12Z
0.733
1.3 4.3
50
3.92
12.39
4.00
0.86
205
1418
1524
4479
-14%
-200%
+17%
NA
14Z
0.730
1.1 - 8.17
50
3.36
10.32
850
0.23
166
585
1858
4513
8%
15%
0%
NA
15Z
0.811
1.2 - 4.3
50
8-11
400
0.44
173
644
1532
4054
4%
6%
17%
NA
13Z
0.144
0.8 - 2.0
50
4.06
11.7
0
0
671
1206
1185
2185
NA
NA
NA
* Not appl cable.
-------
Layer 2 has mixed results. There is a -200 percent additional removal
for Test 12Z with acoustics. This dramatic value is due to the high
concentration of zinc in Layer 2. The values for Test 122 do not smoothly and
continuously increase as would be expected. Rather, the values plateau for
Layers 2 and 3. A repeat analysis of the sample for Layer 2 was made and it
was very close to that reported in the table. It was therefore not a problem
with the analysis. The only explanation offered is that the sample was not
continuous or homogeneous during the test.
The result for Layer 3, Test 142, showed no additional removal. The
major differences between this acoustic test and the other acoustic tests were
the frequency and power. The power was only 0.23 W compared to 0.44 and 0.86
W for the other tests. The frequency was also twice as high at 850 Hz
compared to 400 Hz. Therefore, the lack of removal is probably attributed to
the lower power level and higher frequency.
The main observation that can be made regarding the testing is that much
more is needed. The analytical results have a high degree of variability.
The samples themselves may change over treatment time so that they do not
behave as a continuous medium. These factors contribute to the scatter in the
results, which makes the accurate determination of the BSD effect difficult.
As more and more tests are conducted, the confidence in the results would be
improved.
Questions arise as to the importance of the acoustic field even given
that there is a demonstrated significant increase in removal. First, over a
fixed treatment time, a greater removal may be observed. However, the
question is whether there is a lower limit to the remaining concentration that
can be removed in the presence of the electric field with or without
acoustics. If there is a lower limit, then the application of the acoustics
could only shorten time and/or reduce total energy costs. Given this
scenario, one would have to trade-off treatment costs (energy and time) versus
the capital costs and difficulties to incorporate the acoustic fields.
Other benefits that may be obtained with acoustics is that the treatment
zone may be increased; i.e., for a given placement of electrodes for the
electric field, the treatment volume may significantly increase. This would
certainly represent a greater benefit of the BSD system. This concept has not
been tested with the laboratory apparatus used in this project.
74
-------
Secondary benefits to the acoustics may also exist. For example,
acoustics may help to keep permeability of the soil high, because the
contaminants concentrate at the removal well. Continuity of the electric
field in situ may also improve with the application of the acoustics. Only
with further testing, including large-scale field testing, can these questions
be answered.
ZINC/CADMIUM TEST
One test was conducted on the zinc/cadmium contaminated soil using
the zinc-modified test cell. The objective of the test was to demonstrate
that a mixture of ion contaminants in the soil can be transported in the
presence of electric field. Results of test are shown in Table 17 and details
of the results are provided in Appendix D. The test was conducted at a
constant current of 50 mAmp and an average power of 1 913 W for 100 hours.
The anode layer was flushed with 0.03N acetic acid solution. Acetic acid was
used because it increased the solubility of zinc and cadmium in the soil.
Acetic acid forms a zinc acetate complex and a cadmium acetate complex in the
presence of zinc and cadmium. These complexes are soluble in water even at a
pH higher than 6 (pH 2-9). The formation of these acetate complexes will
reduce the formation of hydroxide complexes, which are insoluble in water.
The treated cake was divided into five layers. A schematic of the five
sections is shown in Figure 22. During zinc tests, the treated cakes were
divided into four layers. The last layer (Layer B in contact with cathode)
showed an accumulation of the metal species, whereas the first three Layers A,
B, and C showed metal removal. To demonstrate that there could be a
concentration gradient within the last layer for the zinc/cadmium test, the
layer was further subdivided into two fractions.
Results of tests confirm that BSD is effective in moving both zinc and
cadmium ions from the cake layer in contact with the anode to the cake layer
in contact with the cathode. For example, Layer A shows a removal of 97.05
percent cadmium and 85.09 percent zinc. In Layer C, removal of cadmium
75
-------
TABLE 17. PERFORMANCE OF BSD PROCESS ON ZINC/CADMIUM SOIL
Layer
Cake Thickness
Gradient (In.)
0 Anode (+)
1
2
3
3.5
4 Cathode (-)
0
1
1
1
0.6
0.4
Zinc Concentration
(mg/kg) dry soil
PH
3.65
3.55
3.64
4.12
7.66-9.2
Zande
0
167
182
207
409
7755
EPA
0
158
167
197
344
7180
Ave
0
163
175
202
377
7468
Percent
Zinc
Removed
100
85.09
83.99
81.52
65.51
-
Cadmium Concentration
(mg/kg) dry soil
Zande
0
29.2
26.0
53.5
207
6187
EPA
0
25
22
51
208
6310
Ave
0
27.1
24.0
52.3
207.5
6249
Percent
Cadmium
Removed
100
97.05
97.39
94.32
77.45
-
Initial Sample Solids % = 56.73%
Initial Zinc Concentration = 1093 mg/kg dry soil (see Table 7)
Initial Cadmium Concentration = 920 mg/kg dry soil (see Table 7)
-------
Layer B
Anode (+)
Layer A
Layer D
Layer C
Layer Bl
Layer B2
Soil in contact with Anode
Soil in between Layer A and C
Soil in between Layer D and Bl
Soil in between Layer C and B2
Soil in contact with Cathode
Cathode (-)
Cake after BSD
Process 4" - 4.5
thickness
Figure 22. Schematic of Cake Divided Sections
for Zinc/Cadmium Test.
77
-------
and zinc was 94.32 and 81.52 percent, respectively. Zinc and cadmium were
also removed in Layer Bl (the layer which was subdivided). This confirms that
there is a concentration gradient in the layer in contact with cathode (B2).
This analysis indicates that both zinc and cadmium removal occurred in more
than 90 percent of the treated cake.
In the remaining 10 percent of cake (Layer B2, 0.4 in.), there was
accumulation of zinc and cadmium due to an increase in pH at the surface of
the cathode. The pH of Layer B2 was between 7.7-9.5. Zinc salt is soluble at
pH below 6, whereas cadmium salts are soluble at pH below 9. Above pH 9,
cadmium would exist as Cd (OH)2, CdC03, CdOH+, CdOHCl, which are insoluble in
water. Figure 23 shows the solubility of cadmium as a function of pH. The
solubility of zinc was discussed earlier in the zinc tests section. Also, for
the prepared zinc/cadmium soil, we have calculated the percentage of zinc and
cadmium and their forms at different pH values, 7, 8, and 9. Again, as
described previously, the calculation was performed using the geochemical
computer code MINTEQA2. Table 18 shows calculation for percent distribution
of zinc and cadmium at pH values of 7, 8, and 9. More detailed analysis is
listed in Appendix E.
Although in the initial concentration of both cadmium and zinc were 0.1
percent, it was observed that there was more cadmium removal than zinc.
Hence, it appears that zinc has higher affinity to the soil than does cadmium.
According to Benjamin and Leckie'35 , zinc will almost completely displace
cadmium and compete for the same soil binding sites. Because of the higher
binding force of zinc to the soil, more cadmium was removed than zinc.
QUALITY ASSURANCE OF ANALYTICAL DATA: ZINC AND CADMIUM
As part of the quality assurance of analytical procedures, chemical
analyses were performed in both U.S. EPA and Zande Laboratories for a set of
soil samples. Comparison of analytical data are given in Tables 20 and 21 for
zinc and cadmium, respectively. For zinc analysis the variations of data
between the two laboratories ranged from 0.48 to 28.91 percent. However, 90
percent of the data showed a variation of less than 20 percent. It was found
that the U.S. EPA reported data were generally higher than Zande results. For
78
-------
£-Cd(OH)2
1
,\,\,
12 13
Figure 23. Distribution Of Hydro'lVS'ls Products (x, y) at I = 1 m and 25' in Solutions
Saturated witb fl-CdfOHJo- The Heavy Curve is the Total Concentration of
rarlmiiim H l^/ .
-------
TABLE 18. PERCENT IONIC DISTRIBUTION FOR ZnCl, AND
CdCl2 AT PH 7, 8, AND 9
pH 7
pH 8
pH 9
Zn+2
85.0 Zn+2
4.9 ZnCl+
8.5 Zn Acetate
74.8 Zn+2
4.3 ZnCl+
4.5 ZnOH
4.0 Zn(OH)2
4.1 ZnOHCl AQ
11.9 Zn+2
7.6 ZnOH
70.6 Zn(OH)2
7.3 ZnOHCl
1.4 Zn Acetate
Cd+2
29.1OT2 ,
53.5 CdCr
6.7 CdCl2
8.2 Cd Acetate
2.0 Cd Acetate 2
28.4Cd+2
52.6 CdCl+
6.6 CdCl2
1.7 CdOHCl
8.3 Cd Acetate
2.1 Cd Acetate 2
22. Kd+2
45.5 CdCl+
6.0CdCl2
1.0 CdOH+
15.1 CdOHCl
7.7 Cd Acetate
2.2 Cd Acetate 2
80
-------
TABLE 19. ZINC QA DATA
Zinc Concentration (mg/kg)
7/25/89
8/15/89
02363
02364
02365
02366
02374
1167
1689
1475
1492
1415
1195
1164 (duplicate)
1767
1711 (duplicate)
1527 (no duplicate)
1548
1546 (duplicate)
1419 (no duplicate)
81
-------
TABLE 20. ANALYTICAL DATA FOR ZINC SOIL
Test
No.
521
5Z2
6Z1
6Z2
7ZA
7ZD
7ZC
7ZB
8ZA
8ZD
8ZC
8ZB
9ZA
9ZD
9ZC
9ZB
10ZA
10ZO
10ZC
10ZB
Zinc Concentration,
mq/Kq (DS)
Zande
2135
383
208
1878
180
687
1847
5644
818
1542
2066
3214
118.6
174.7
204.6
6341
1175
1529
1501
1722
U.S. EPA
1870
272
210
2220
198
852
1940
5310
852
1900
2100
2720
155
253
371
4820
1800
2000
2040
2120
Percent^
Variability Between
Zande and U.S. EPA
6.61
16.95
0,48
8.35
4.76
10.72
2.46
3.05
2.08
10.40
0.82
8.32
13.34
18.31
28.91
13.63
21.01
13.35
15.22
10.36
(a) Percent variability =
/"EPA + Zandej
EPA
EPA + Zande
82
-------
rABL ANAL ICAL DATA FOR CADMIUM SOILS
Sample
Zn-Cd Feed (1)
Zn-Cd Feed (2)
1ZCA
1ZCB1
1ZCB2
1ZCC
1ZCD
Cadmium
EPA
866
873
25
208
6310
51
22
(mg/kg)
Zande
976
955
292
"207
6167
535
26
-------
cadmium, however, the analytical data reported from both laboratories agreed
fairly well (Table 21). The variation of the results was less than 8.3
percent.
QC Data for Zinc and Cadmium
The QC data provided by U.S. EPA for zinc and cadmium analyses are
given in Tables 22 and 23, respectively. When spiked at 1 ppm to the standard
solution, recovery of zinc varied from 97 to 106 (see Table 22). Also, the
spiking of soil samples with zinc resulted in a recovery of 85 to 103 percent.
These spike recovery levels for both liquid and solid samples along with the
reported precision data (see duplicate analysis in Table M) indicate a high
precision and accuracy of zinc analysis. Similarly, high precision and
accuracy data are reported for cadmium analysis (see Table 23).
INTERNAL AND EXTERNAL QUALITY ASSURANCE AUDITS
Three internal QA audits were performed by Battelle's Quality
Assurance Unit which is independent of the research groups that conducted this
study. The QA Unit examined the Quality Assurance Project Plan and observed
whether the QA/QC requirements are met. The QA Unit also examined the
laboratory record books. As a part of the audit program, Zande Laboratory was
also audited while they were performing the sample analysis. When deviation
from the QAPP was observed, appropriate corrective action was taken and
documented.
A Technical System Review (TSR) or the external audit was performed by
PEI Associates, Inc. under the direction of U.S. EPA. No concerns were noted
in (a) pilot plant operation and sample acquisition and (b) test methods and
analytical procedures:
(1) Battelle identified a problem in obtaining a representative sample
of the test soil contaminated with decane after treatment. The cake
(three inches in diameter and up to 2 inches thick) obtained from
the test cell has the consistency of a thick paste. Dewatering was
stratified with the drier material on the top. If the sample is
mechanically mixed, additional liquid separates, making it difficult
to obtain a representative sample. Alternatives were discussed
including quartering the cake and taking alternate quarters,
84
-------
TABLE 22. ~QC DATA FOR ZINC
Sample ID Concentration % Recovery
QC Standard 1 ppm 104
QC Standard 1 ppm 106
5Z2 272 mg/kg
5Z2 (duplicate) 297 mglkg
5Z2 (material spike) 103
5Z2 (material spike, duplicate) 101
QC Standard 1 ppm 97.3
1ZCB1 344 mq/kg
1ZCB1 (duplicate) 350 mg/kg
1ZCB1 (material spike) 85
1ZCB1 (material spike, duplicate) 87
85
-------
TABLE 23. QC DATA FOR CADMIUM
Sample ID Concentration % Recovery
QC Standard 1 ppm 90-4
1ZCB1 208 mg/kg
1ZCB1 (duplicate) 206 mg/kg
1ZCB1 (material spike) 98
1ZCB1 (material spike, duplicate) 105
86
-------
extracting the entire cake, or coring the cake with a cork borer.
The samples for zinc analysis do not present the same problem
because the soil can be dried and ground to a uniform consistency
with a mortar and pestle.
(2) There was a calculation error in the standards for the GC analysis.
The concentration of the standards were listed as ppm, but these
were volume/volume ppm. The analytical data based on these
standards were also reported as ppm, but the analytical data should
be ppm on a weight/weight basis. The concentration of the standards
needed to be converted to nanograms per microliter (using the
density of decane) , and the analytical data recalculated to obtain a
weight/weight relationship.
As a resolution to the first issue, it was decided to quartering the cake
(thin slice) and taking alternate quarters for analysis. Extraction of the
entire cake or a slice was the preferred approach, but the resources did not
permit doing so. As for the second issue, data were recalculated to convert
the ppm values from volume/volume basis to weight/weight relationship.
87
-------
SECTION 6
COMPARISON OF TECHNICAL PERFORMANCE OF ESD
WITH OTHER IN SITU TECHNOLOGIES
Based upon the results of this limited study, it is not possible to make
a direct quantitative comparison of the ESD technology to other technologies;
however, a qualitative comparison is possible. Table 24 summarizes these
comparisons.
Organics Treatment
The most likely ESD application for treatment of organics is to enhance
the recovery of non-aqueous phase liquids (NAPL) such as solvents and fuel
oils. Another possible application is to enhance recovery of more soluble
polar organics. This application would be more like the metals treatment.
ESD has the potential to reduce NAPL concentrations at or near saturation
levels (approximately 5,000 -50,000 rag/kg) to below saturation (approximately
100 1,000 mg/kg), but most probably not to low rag/kg or rag/kg levels. This
discussion will focus on the potential for increased NAPL recovery.
Pump and Treat
Conventional technology for NAPL recovery consists of some form of
groundwater and/or NAPL pumping followed by NAPL separation and/or water
treatment. This technology typically can succeed in controlling groundwater
and NAPL flow and decreasing the potential for off-site migration. However,
success in substantially reducing residual contamination is limited. One
limitation of pump-and-treat is that conventional NAPL recovery is dependent
upon gravity drainage to bring the NAPL into a recovery well or trench for
skimming.
As water tables move up and down and vadose zone moisture levels change,
the fraction of the NAPL in this free floating phase changes. As a result, a
88
-------
TABLE 24. COMPARISON OF ELECTRO-ACOUSTICAL SOIL DECONTAMINATION (ESD) TO OTHER IN-SITU TECHNOLOGIES
CD
<£>
Technology
In-Situ Biodegradation
I norgan i cs Treatment
ESD
Direct current
Pump and treat
In-Situ vitrification
Status
Cost
Limitations
Limited commercial
availability
Bench-scale
Pilot Scale
Commercially available
Commercially available
Low-high
Low?
Low?
Low initial cost
but potentially
high life cycle
cost.
High
Not fully proven, limited
to biodegradable compounds.
Unproven.
Unproven.
Never ending, limited to
saturate zone.
Stabilizes metals in place,
rather than removing them.
'•'V
-------
TABLE 24. (CONTINUED)
Technology
Status
Cost
Limitations
Organic treatment
ESD'
Pump and treat
Soil venting
Heat enhanced soil
Steam injection
Early bench scale
Commercially available
Commercially available
Limited commercial
availability
Limited commercial
availability
RF heating Pilot scale
Direct current heating Bench/pilot scale
In-Situ vitrification Commercially available
Low?
Low initial cost
but potentially
high life cycle
cost.
Low (without air
treatment)
Moderate (with air
treatment)
Moderate - high
High
Moderate - high
Moderate - high
Highest
Unproven
Never ending, limited to the
saturated zone.
Limited to volatiles in the
vadose zone.
Limited to semivolatiles in
the vadose zone.
Limited field experience.
Limited field experience.
Limited field experience
Very high temperatures and
energy cost.
-------
NAPL recovery system may reduce or even remove the measurable NAPL phase only
to have it return under different hydrological conditions.
Under the new RCRA underground tank regulations (CFR 280.64) the minimum
remediation requirements are "free product removal." Achievement of this
level of remediation may be difficult using conventional pump-and-treat
technology. ESD coupled with a conventional pump-and-treat technology has the
potential to reduce relatively rapidly the residual NAPL concentrations to
levels below those which would result in the free phase NAPL or "free product"
layer
Soil Venting
Soil vent, soil vacuum extraction, and in-site volatilization, is a
relatively simple and widely utilized technology for removing volatile organic
compounds from the vadose zone. If off-gas treatment is unnecessary, costs
are very low; if treatment is required, costs are moderate. Where off- gas
treatment is required, ESD has the potential to be less expensive than soil
venting and in some cases may prove to be a cost-effective pretreatment prior
to soil venting. It is unlikely that ESD can achieve residual concentrations
as low as those possible with soil venting for volatiles.
Heat Enhanced Soil Venting
Some vendors of soil venting services have begun to inject heated air to
accelerate the process and extend treatment to less volatile or semivolatile
organics. The cost of energy to heat the soils is moderately high, dependent
of course upon the targeted temperature. Comparisons to ESD are similar to
those discussed above for soil venting.
91
-------
Steam Injection
Injection of steam to treat volatiles and some less-volatile compounds
has been demonstrated on a limited number of sites. Sufficient data are not
yet available to fully evaluate its feasibility, however energy costs are
high. Because of the increased heat capacity of the wet soils, more heat and
therefore, energy are required than for other soil heating technologies.
Radio Freauencv Heating
Radio frequency heating is an emerging technology for in situ soil
heating. Roy F. Weston, the licensed vendor, intends to couple it with soil
venting to achieve accelerated remediation. The comparison to ESD would be
very similar to those discussed above.
Direct Current Heating
Direct current is being explored as a means of soil heating. As for all
technologies that require increased soil temperature, more energy would be
required than for ESD.
In-Situ Vitrification
In-Situ vitrification (ISV) is a commercially available technology in
which a direct current is applied to the soils to achieve super heating. This
results in soils melting to form a vitrified solid. This differs from direct
current heating only in that much higher temperatures are achieved and
correspondingly higher energy costs are incurred. ISV is typically applied to
inorganics; however, limited data suggest it is applicable to a wide range of
organic compounds. The organics are probably either volatilized or are
oxidized. Because of the high cost, ISV will most likely only be utilized at
very high hazard sites where very low cleanup levels are required. ESD alone
would most likely not be applicable to these sites.
92
-------
Biodeqradation
In situ biodegradation is a technology that is receiving widespread
attention. It has, to date, been proven effective at a limited number of
sites and for a limited number of compounds. The technology is only
applicable to biodegradable organics. As the technology evolves, more wide-
spread application may occur. At some sites, BSD may prove to be a cost-
effective pretreatment prior to application of an in situ biodegradation
technology.
MATERIALS TREATMENT
BSD usage for removal of metal ions is a distinctively different
application of the technology from NAPL organics treatment. In this
application, BSD may or may not be coupled with a more conventional pump-and-
treat technology. BSD has the potential to substantially reduce residual
metals concentrations to or below the low mg/kg or mg/kg level. Unlike
organics treatment, there are a relatively limited number of technologies for
the treatment of metals in-situ.
Direct Current
Direct current has been applied to remove metals in-situ. The Dutch
Geokinetics process is a promising technology, utilizing a novel circulating
fluid electrode to prevent metals deposition. The direct-current technology
is a part of the BSD technology; however, by combining electrical and
acoustical fields, BSD has the potential to improve treatment efficiency.
Pump and Treat
As discussed for organics treatment, the pump -and-treat technology is
potentially successful at hydraulically controlling a plume of contaminated
groundwater but is frequently ineffective at substantially reducing residual
soil contamination. BSD has the potential to improve substantially this
treatment.
93
-------
In-Situ Vitrification
In-situ vitrification was designed for and is typically applied to
inorganic contaminants. Direct current is applied to heat the soil to its
melti ng point and vitrify the contaminated soil into an impermeable mass.
This technology does not remove the metals but rather immobilizes them in
situ. The technology requires substantially more energy and funds than does
BSD.
94
-------
SECTION 7
CONCLUSIONS
(1) Electro-acoustic decontamination of soil in a laboratory mode was
proven technically feasible for inorganic contaminants.
(2) Zinc removal/concentration (80-90 percent) was observed in the
presence of the electric field.
(3) There appears to be a combined electric and acoustics effect during
zinc removal. However, further testing is required to determine
accurately the magnitude of the effect.
(4) Longer leaching times yielded higher zinc removal efficiencies.
(5) Higher power levels yielded higher zinc removal rates.
(6) Cadmium/zinc removal/concentration (90-95 percent) was observed in
the presence of the electric field.
(7) A large discrepancy was observed between U.S. EPA and Zande Labs
decane analyses.
(8) Since a large variability in analytical determination of decane in
the soil was observed, no definitive conclusions can be drawn on the
effect of electro-acoustics on decane removal from soils.
95
-------
SECTION 8
RECOMMENDATIONS
Based on Phase 1 laboratory experimental results for decontamination of
heavy metals in clayed soil, a study is recommended and should be conducted to
further evaluate the BSD process in field conditions. Such a study would
validate the Phase I results and would provide the basis for developing design
and operational changes for successful field applications.
We also recommend no additional work on the decane contaminated soil
until the analytical and experimental problem can be solved. The results from
the decane experiments were inconclusive because of substantial experimental
uncertainty in the decane analysis and also possibly in experimental
procedures.
96
-------
SECTION 9
REFERENCES
1. 1986 Undersround Motor Fuel Storage Tanks: A National Survey. Vol. 1,
U.S. EPA Technical Report 560/5-86-013, Washington, D.C., 1986.
2. Houy, G. E. and M. C. Marley, "Gasoline Residual Saturation in Uniform
Aquifer Materials", T. Env. Enq.. ASCE 112(3): 586-604, 1986.
3. Casagrande, L. , "Electroosmosis and Related Phenomena", Harvard Soil
Mechanics Series No. 66 (1962).
4. Casagrande, L. , "Review of Past and Current Work in Electroosmotic
Stabilization of Soils", Harvard Soil Mechanics Series NO. 145 (1957).
5. Muralidhara, H. S., and D. Ensminger, "Acoustic Dewatering and Drying:
State-of-the-Art Review," Proceedings IV, International Drying Technology
Symposium, Kyoto, Japan, 1984.
6. Muralidhara, H. S. , and N. Senapati, "A Novel Method of Dewatering Fine
Particle Slurries," presented at International Fine Particle Society
Conference, Orlando, Florida, 1984.
7. Muralidhara, H. S. , et al. , Battelle's Dewatering Process for Dewatering
Lignite Slurries, Battelle Phase I Report to UNO Energy Research
Center/EPRI, 1985.
8. Chauhan, S. P. , H. S. Muralidhara, B. C. Kim, "Electroacoustic Dewatering
of POTW Sludges", Proc. National Conf. on Municipal Treatment Plant Sludge
Management, Orlando, Florida, May 28-30, 1986.
9. Muralidhara, H. S. , et al. , "A Novel Electro Acoustic Process for
Separation of fine Particle Suspensions", Ch. 13, pp. 374, in Advances in
Solid-Liauid Separation. Editor H. S. Muralidhara.
10. Muralidhara, H. S. , N. Senapati, and B. K. Parekh, Solid-Liquid Separation
Process for Fine Particle Suspensions by an Electric and Ultrasonic Field,
U.S. Patent 4,561,953, December 1985.
11. Senapati, N. , H. S. Muralidhara and R. E. Beard on "Ultrasonic
Interactions in Electra-acoustic Dewatering", presented at British Sugar
Technical Conference, Norwitch, U.K., June 1988.
12. Muralidhara, H. S. , "Recent Developments in Solid-Liquid Separation",
presented at the Trilaterial Particuology Conference in Peking, China,
September 1988.
97
-------
13. Beard, R. E., and H. S. Muralidhara, "Mechanistic Considerations of
Acoustic Dewatering Techniques", Proc. IEEE, Acoustic Symposium, pp. 1072-
1074, 1985.
14, Muralidhara, H. S., Editor, Recent Advances in So lid-Li au id Separation.
Battelle Press, Columbus, OH, November 1986.
15, Hunter, C. J., Zeta Potential in Colloid Science Principles, and
Applications. Academic Press, 1981.
16, Bell, T. G., U.S. Patent No. 2,799,641 (1957)
17. Paris, S. R., U.S. Patent No. 3,417,823 (1968).
18, Gill, W. G., U.S. Patent No. 3,642,066 (1972)
19. Bell, C. W., and Titus, C. H., U.S. Patent No. 3,782,465 (1974).
20. Kermabon, A. J., U.S. Patent No. 4,466,484 (1984).
21. Hardy, R. M., Unpublished presentation at NRC Canada, Ottawa, Canada (Dec
1953).
22. Banerjee, S., "Electrodecontamination of Chrome-Contaminated Soils", Land
Disposal, Remedial Action, Incineration and Treatment of Hazardous Wastes
Proc. Thirteenth Annual Research Symposium, pp. 192-201 (July, 1987).
23 Horng, J. J., Banerjee, S., and Hermann, J. G., "Evaluating
Electrokinetics as a Remedial Action Technique", Second International
Conference on New Frontiers for Hazardous Waste Treatment, Pittsburgh PA
(Sept. 27-30, 1987).
24. Anbah, S. A., et al., "Application of Electrokinetic Phenomena in Civi
Engineering and Petroleum Engineering", Annuals, Volume 118, Art. 14,
(1965).
25. Lageman, R., "Electro Reclamation in Theory and Practice", presented at
Forum on Innovative Hazardous Waste Treatment Technologies at Atlanta,
Georgia, June 19-21, 1989.
26. Hamnett, R., "A Study of the Processes Involved in the Electro Reclamation
of Contaminated Soils", Master of Science Degree thesis, submitted to V.
Manchester, U.K., October, 1980.
27, Probstein, R. F. and P. C. Renaud, "Quantification of Fluid and Chemical
Flow in Electrokinetics", presented at University of Washington, Workshop
on Electrokinetic Treatment and its Application in Environmental
Geotechnical Engineering for Hazardous Waste Site Remediation at Seattle,
Washington, August 4-5, 1986.
28. Mitchell, J. K, "Potential Uses of Electrokinetics for Hazardous Waste
Site Remediation", presented at Electrokinetic Treatment and its
Application in Environmental Geotechnical Engineering for Hazardous Waste
Site Remediation, Seattle, Washington, August 4-5, 1986.
98
-------
29. Kelsh, D. J., and R. H. Sprate, "Dewatering Fine Particle Waste
Suspensions with Direct Current", Encyclopedia of fluid Mechanics, Chapter
27, pp. 1171-1188, 1986.
30. Fleureau, J. N. and M. Dupeyrat, "Influence of an Electric Field on the
Interfacial Parameters of Water/Oil Rock System Application to Oil
Enhanced Recovery", T. Colloid and Interface Sci.. 123(1), p. 249-258,
1988.
31. Lockhart, N. C., "Electroosmotic Dewatering of clays III Influence of clay
Type Exchangeable Cations and Electrode Materials", Colloids and Surfaces,
6, 253-269 (1983).
32. Puri, A. N. and Anand, B. , "Reclamation of Alkali Soils by
Electrodialysis", Soil Science. 42, p. 23-27, 1936.
33. Blok, L. , DeBruyn, P. L. , "The ionic double layer at the Zno/Solution
interface 1. The experimental point of zero charge" .T. Coll. Interface.
Science, 32, p. 518-538, 1970.
34. Baes, Charles F. , Jr. and Robert E. Mesmer, "The Hydrolysis of Cations",
1986.
35. Rai, D. , et al. , "Chemical Attenuation Rates, Coefficients, and Constants
in Leachate, Migration", report prepared by Battelle Pacific Northwest
Laboratories, for EPRI, EPRI Project NO. EA-3356, Vol. I, February 1984
(P9-5)
36. Beard, R. , F. B. Stulen, Summary Report for Concept Study on Down Hole
Skin Removal, A Gas Transmission Company. June 1985.
37. Armour Research Foundation Technical Report No. 2, by F. G. Tyzzer and H
C. Hardy, March 1951, DA-44-009 Eng-106
99
-------
APPENDIX A
DECANE DATA
100
-------
DECANE TEST DATA
Initial Decane % as dosed in the
Initial Decane % as dosed in the
Initial Solids % as dosed in the
Test
Test
1
10D*
UD*
12D*
13D*
Time
Hr
1.25
1.25
1.25
1.75
Voltage
volts/in.
37.5
25.0
12.5
25.0
lab = 8.0 (D.B.)
lab = 4.21 (W.B.)
lab = 52.68
Acoustic
Current
Amp
0.18
0.16
0.08
0.19
Power
Watts
0
0
0
0
Final
BSD
Treated Soil Analysis
Cake EPA Decane
Zande
Decane
Solids % % (W.B. ) %(D.B.) %(W.B.) %(D.B.)
68.52
-------
DECANE TEST DATA
(Continued)
Initial Decane % as dosed in the lab = 7.97 (D.B.)
Initial Decane % as dosed in the lab = 4.20 (W.B.)
Initial Solids % as dosed in the lab = 52.68
Test
Test Time Voltage
I Hr volts/in.
ESP Treated Soil Analysis
Acoustic Final
Current Power Cake
Amp Watts Solids % %(W.B.) %(D.B.) % (W.B. )%(D.B.)
EPA Decane
Zande Decane
Comments
14D* 1.25
25.0
15D*
1.25 0
20D* 24.0 5.0
21D* 24.0 S.(
0.15
17D* 2.0 12.5 0.08
18D* 141.5 6.25-41.25 0.008
0.009
0
66.30
(a)
3.170 4.78
53.73
(a)
3.480 6.476
64
.5
-------
DECANE TEST DATA
(Continued)
Initial Decane % as dosed in the lab
Initial Decane % as dosed in the lab
Initial Solids % as dosed in the lab
7.97 (D.B.)
4.20 (W.B.)
52.68
ESP Treated Soil Analysis
Test' Acoustic Final
Test Time Voltage Current Power Cake EPA Decane
# Hr volts/in. Amp Watts Solids % %(W.B.) %(D.B.) %(W.B.) %(D.B.) Comments
Zande Decane
22D*
1.25
1 watt 54.7(a)
400 Hz
2.890 5.28
3.6900 6.75
Sample was mixed for
analysis.
23D*
1.25
26DA* 2.0
26DA1* 2.0 37.5
26DA2* 2.0 37.5
26DB* 2.0 37.5
0 0.47 watts 55.3^
400 Hz
37.5 0.13
0
73.67
^
3.4400 6.22
3.96 5.38
3.90
4.45
4.3
5.29
6.040
6.07
3.6400 6.58
6.71 9.11
6.55 8.89
5.82 7.91
5.95 8.40
Sample was mixed for
analysis.
Cake was divided into
three sections. Section
A - closer to the anode.
Section B - between
Section A & C. Each
section is 0.5 in
thickness. Total cake
thickness 2.5 in.
No mixing.
-------
DECANE TEST DATA
(Continued)
Initial Decane % as dosed in the lab = 7.97 (D.B.)
Initial Decane % as dosed in the lab = 4.20 (W.B.)
Initial Solids % as dosed in the lab = 52.68
Test1
Test' Time Voltage
# Hr volts/in.
Acoustic Final
Current Power Cake
Amp Watts Solids
ESP Treated Soil Analysis
EPA Decane
Zande Decane
% %(W.B.) %(D.B.) %(W.B.) %(D.B.) Comments
26DC*
27DA*
2.0
2.0
37
45
.5
.0
0.11 0 72.65^
3
4
.9
.35
6
5
.29
.987
5.
6.
53
47
8.9
8.91
27DB* 2.0 45.0
27DC* 2.0 45.0
28DA* 2.0 25.0
0.10
61.24a 4.17 6.809
50.58^a^ 3.56 7.038
70.35(a) 4.29 6.098
5.21
5.89
5.93
7.25
8.51
11.64
9.37
Cake was divided into
three sections', Section
A - closer to the anode.
Section B - between
Section A & C. Each
section is 0.5 in
thickness. Total cake
thickness 2.5 in.
Cake was divided into
three sections. Section
A - closer to the anode.
Section B - between
Section A & C. Each
section is 0.5 in
thickness. Total cake
thickness 2.5 in.
-------
DECAWE TEST DATA
(Continued)
Initial Decane % as dosed in the lab = 7.97 (D.B. )
Initial Decane % as dosed in the lab = 4.20 (W.B. )
Initial Solids % as dosed in the lab = 52.68
Test'
Test' Time
# Hr
28DB* 2.0
28DC* 2.0
SODA* 2.0'
Voltage
volts/in.
25.0
25.0
37.5
Acoustic
Current ' Power
Amp Watts
0
0
0.11 0.697
400 Hz
Final BSD Treated
Cake EPA Decane
Solids % %(W.B.) %(D.B.)
65.60^ 4.07 6.204
59.89^a^ 3.34 5.576
73.79^ 4.44 6.017
Soil Analysis
Zande Decane
%(W.B.) %(D.B.) Cements
4 . 98 7.6
6.28 10.49
6.10 8.27 Cake was divided into
three sections. Section
A - closer to the anode.
Section B - between
Section A & C. Each
section is 0.5 in
thickness. Total cake
thickness 2.5 in.
30DB*
30DC*
2.0
2.0
37.5
37.5
0.697 68.01W
400 Hz
0.697 61.40^
400 Hz
3.90
3.54
5.13
5.77
5.94
5.13
8.73
8.36
(a) Final solids percent reported by Zande.
Note:' 2 in. cake was used in test 10D through 23D.
2 1/2 in cake was used in 26D through 300.
-------
APPENDIX B
ZINC DATA
106
-------
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1)2. S
122.1
S2I 1
SSIS
1111(11
III
tcrccil
UK r
Ititnl S
II IS
IS 21
11.21 ID
III 1 III
1! 11
11.11
1 II
Ml 1
li 2
II 11
il il
211. S
IH Id
liude Lucille
n n
1)4 1112
) )i 1112
) )! 11 11
111 11. )2
I--II
l-ll
l-ll
l-ll
1.14 4.1
1.14 II
1.11 II
111 4.1
Clll
Clll
cilc
cilc
cilc
cile
cat
Mil
cilc
cilc
cilc
cilc
Coiieii
II CtlllCl
It camel
il COIllCl
li culicl
ll CtlllCl
II CtltlCl
ll CtlllCl
ll CtlllCl
ll CtlllCl
ll COIllCl
ll CtlllCl
ll CtlllCl
lllk node
lllk node luci
ink cilktdc Intr
lllk cilktde
lllk node .
lllk lltde ll|tl
lllk cilktdt liltr
lllk citkode
lllk iitde
lllk utdc liter
illk cilktde liltr
lllk Cilktdt
III: Fccccit luc Iccanlilcl
I ten in fc[l«fit< li i KiJiiitl crllidtr dciuitd Itl (Uiklii ftirftiti
lk|: PI tl Ililllll liltr ui.tlol H Ike u4 ll leil
lc|: PI of leickile it Ike ci4 tl lill
II): hillcilt iiiliiu
ll): fciccit Ilic Icitiel Iui4 H In4t Illlfllcil liti
i Iliikui niti friucl Ikituik end li Ike itil
-------
APPENDIX C
GEOCHEMICAL CALCULATIONS
FOR ZINC SOIL
110
-------
Zinc at pH 6 (pg
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/24/89 TIME: 16:38:42
Zinc Solubility and Percent Distribution at pH 6
Temperature (Celsius): 25.OO
Units of concentration: PPM
Ionic strength to be computed.
Carbonate concentration represents carbonate alkalinity.
Do not automatically terminate if charge imbalance exceeds 30V.
Precipitation is allowed only for those solids specified as ALLOWED
in the input file (if any).
The maximum number of iterations is: 10O
The method used to compute activity coefficients is: Debye-Huckel equation
Do not print the full species database including gram-formula weights and
Debye-Huckel parameters.
LOG GUESS ANAL TOTAL
-1.820 2.00OE+03
-1.250
-6.OOO
950 0.200E+04 -1.82
180 0.200E+04 -1.25
330 0.101E-04 -6.0O
0 H20 HAS BEEN INSERTED AS A COMPONENT
3 1
330 6.0000 O.OOOO
OINPUT DATA BEFORE TYPE MODIFICATIONS
0 ID NAME ACTIVITY GUESS
950 Zn+2 1.514E-O2
ISO Cl-1 5.623E-O2
33O H+l l.OOOE-06
2 H20 l.OOOE+OO
0 ID NAME ANAL MOL CALC MOL
NEW LOCK DIFF FXN
95O Zn+2 2.0OOE+03 O.OOOE+OO 1.514E-O2
0.0000 O.OOOE+00
ISO Cl-1 2.0OOE+03 O.OOOE+00 5.623E-O2
0.0000 O.OOOE+OO
330 H+l 1.008E-05 O.OOOE+00 1.OOOE-O6
6.0000 O.OOOE+00
2 H2O O.OOOE+00 O.OOOE+00 l.OOOE+OO
O.OOOO O.OOOE+OO
O.OOO
ACTIVITY
2.000E+03
1.OO8E-O5
O.OOOE+00
LOG ACTVTY
-1.82000
-1.25OOO
-6.00000
0.00000
0
O
CATIONS)
1
GAMMA
1.000000
1.000000
l.OOOOOO
l.OOOOOO
CHARGE BALANCE: UNSPECIATED
SUM OF CATIONS= 6.144E-02 SUM OF ANIONS = 5.664E-02
PERCENT DIFFERENCE = 4.062E+OO (ANIONS - CATIONS)/(ANIONS
111
-------
Zinc at pH 6 (pg 2)
0 SPECIES: TYPE III - FIXED SOLIDS
0 ID NAME CALC MOL LOG MOL
2 H20 -3.352E-05 -4.475
330 H-t-1 3.353E-05 -4.475
1
NEW LOGK DH
0.001 0.000
6.00O 0.000
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: OB/24/89
TIME: 16:39:12
PERCENTAGE DISTRIBUTION OF COMPONENTS AMONG
species
dissolved and adsorbed
+C1-1
+H20
•M-H-1
94.0 PERCENT BOUND IN SPECIES # 950 Zn+2
PERCENT BOUND IN SPECIES 4*9501800 ZnCl
PERCENT BOUND IN SPECIES # 180 Cl-1
PERCENT BOUND IN SPECIES #9501800 ZnCl
48.9 PERCENT BOUND IN SPECIES #9501804 ZnOHCl AQ
5O.1 PERCENT BOUND IN SPECIES #9503300 ZnOH
48.9 PERCENT BOUND IN SPECIES #9501804 ZnOHCl AQ
PERCENT BOUND IN SPECIES #9503300 ZnOH
IDX
NAME
EQUILIBRATED MASS DISTRIBUTION
DISSOLVED
MOL/KG PERCENT
SORBED
MOL/KG PERCENT
PRECIPITATED
MOL/KG PERCENT
950
ISO
2
33O
Zn+2
Cl-1
H20
H+l
3.
5.
3.
-3.
072E-02
664E-02
352E-05
352E-05
1OO
10O
100
100
.0
.O
.0
.0
0.
0.
0.
O.
OOOE+00
OOOE-t-OO
OOOE+OO
OOOE+00
O.O
0.0
0.0
0.0
0
O
0
0
.OOOE+OO
.OOOE+OO
.OOOE+00
.OOOE+00
0.0
0.0
0.0
0.0
CHARGE BALANCE: SPECIATED
SUM OF CATIONS
5.951E-O2 SUM OF ANIONS 5.475E-02
112
-------
Zinc at pH 6 (pg 3)
O PERCENT DIFFERENCE = 4.168E+OO
CATIONS)
O NONCARBONATE ALKALINITY = 1.298E-O8
0 IONIC STRENGTH = : 8.6O1E-02
1
PC VERSION: MINTEOA2 DATE OF CALCULATIONS: 08/24/89
(ANIDNS - CATIONS)/(ANIONS
TIME: 16:39:13
©Saturation indices and
O ID * NAME
each component
4195OOO 2NCL2
2O950OO ZN(OH)2 (A)
2095001 ZN(OH)2 (C)
2095OO2 ZN(OH)2 (B)
2095003 ZN(OH)2 (G)
2095004 ZN(OH)2 (E)
4195001 ZN2(OH)3CL
l.OOO)18O
4195002 ZN5(OH)8CL2
2.0OO)180
2095005 ZNO(ACTIVE)
2095O06 ZINCITE
stoichiometry of all minerals
Sat. Index Stoichiometry in parentheses) of
11.702
-2.37O
-2.120
-1.670
-1.630
-1.420
-2.417
-2.854
-1.230
-1.060
( 1.000)950 (
( -2.000)330 (
( -2. OOO) 330 (
( -2.000)330 (
( -2. OOO) 330 (
( -2.000)330 (
( -3.000)330 (
( -8.000)330 (
( -2.000)330 '(
( -2.000)330 (
2.000)180
1.0OO)95O
1.000)950
1.000)950
1.000)950
1.0OO)95O
2.OOOJ95O
5.000)950
1.000)950
1.0OO)95O
( 2.000)
( 2.000)
( 2.000)
( 2.000)
( 2. OOO)
( 3 . OOO )
( 8.000)
( 1.000)
( l.OOO)
2
2
2
2
2
2
2
2
2
113
-------
Zinc at pH 9.7 (py I)
PC VERSION: MINTEOA2 DATE OF CALCULATIONS: 08/24/89 TIME: 16:48:04
Zinc Solubility and Percent Distribution at pH 9.7
Temperature (Celsius): 25.OO
Units of concentration: PPM
Ionic strength to be computed.
Carbonate concentration represents carbonate alkalinity.
Do not automatically terminate if charge imbalance exceeds 3O"/.
Precipitation is allowed only for those solids specified as ALLOWED
in the input file (if any).
The maximum number of iterations is: 1OO
The method used to compute activity coefficients is: Debye-Huckel equation
Do not print the full species database including gram—formula weights and
Debye-Huckel parameters.
ct
95O
180
500
330
0.20OE+O4
0.218E+O4
0.100E+03
0.101E-04
-1.82
-1.25
-2.40
-9.7O
O H20 HAS BEEN INSERTED AS A COMPONENT
1 1
33O 9.7OOO O.OOOO
OINPUT DATA BEFORE TYPE MODIFICATIONS
ID NAME
950 Zn-t-2
180 Cl-1
5OO Na+1
33O H+l
2 H20
I D NAME
NEW LOCK DIFF FXN
950 Zn+2
O.OOOO O.OOOE+OO
180 Cl-1
O.OOOO O.OOOE+OO
5OO Na+1
O.OOOO O.OOOE+OO
33O H+l
9.70OO O.OOOE+OO
2 H20
O.OOOO O.OOOE+OO
ACTIVITY
1.5.
5.6:
3.9(
1.9<
1.0<
ANAL MOL
2.0OOE+O3
2.18l!f.+03
1.0OOf-:+O2
"i.oorat --O5
o.ooo;-.+oo
5UESS LOG GUESS ANAL TOTAL
»E-02
XE-02
LE-03
5E-10
3E+00
CALC MOL
O.OOOE+OO
O.OOOE+OO
O.OOOE-t-OO
O.OOOE-t-OO
O.OOOE+OO
-1.820
-1.25O
-2.40O
-9.700
0.000
ACTIVITY
1.514E-02
5.623E-02
3.981E-03
1.995E-10
i.OOOE+OO
2.00OE+03
2.181E+03
l.OOOE+02
1.008E-05
O.OOOE-t-OO
LOG ACTVTY
-1.82000
-1.25OOO
-2.40OOO
-9.70000
O.OOOOO
GAMMA
l.OOOOOO
l.OOOOOO
l.OOOOOO
l.OOOOOO
l.OOOOOO
CHARGE BALANCE: UNSPECIATED
114
-------
Zinc at pH 9.7 (pg 2)
9501802 ZnC13 -
0.602 9.56O
95O18O3 ZnC14 -2
0.582 1O.96O
95O330O ZnOH +
-8.86O 13.399
9503301 Zn(OH)2 AQ
-16.906 O.OOO
9503302 Zn(OH)3 -
-28.299 O.OOO
95O3303 Zn(OH)4 -2
-4O.80O 0.000
0 SPECIES: TYPE
0 ID NAME
2 H20
1.143E-10 O.OOOOOOO -10.04407 0.790735
5.251E-12 O.OOOOOOO -11.66251 O.414223
2.986E-O5 O.OOO0237 -4.62477 O.794654
2.269E-O2 O.O230788 -1.63679 1.017O06
7.763E-O3 O.OO61687 -2.20980 O.794654
2.O72E-04 O.OOOO826 -4.08282 O.398760
III - FIXED SOLIDS
CALC MOL LOG MOL NEW LOGK DH
-1.151
0.001
-7.O65E-02
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/24/89
0.000
TIME: 16:48:38
PERCENTAGE DISTRIBUTION OF COMPONENTS AMONG
species
dissolved and adsorbed
+C1-1
-i-Na+1
+H+1
73.9 PERCENT BOUND IN SPECIES #9503301 Zn(OH)2 AO
PERCENT BOUND IN SPECIES #9503302 Zn(OH)3
99.9 PERCENT BOUND IN SPECIES * 180 Cl-i
100.0
PERCENT BOUND IN SPECIES # 50O Na+1
855.1 PERCENT BOUND IN SPECIES H95O18O4 ZnOHCl AQ
>1OOO. PERCENT BOUND IN SPECIES K330OO20 OH-
752.6 PERCENT BOUND IN SPECIES K95O33OO ZnOH +
>1000. PERCENT BOUND IN SPECIES K95O33O1 Zn(OH)2 AQ
>1000. PERCENT BOUND IN SPECIES #9503302 Zn(OH)3
>10OO. PERCENT BOUNO IN SPECIES #9503303 Zn(OH)4 -2
115
-------
+H2O
Zinc at pH 9.7 (pg 3)
1.5 PERCENT BOUND IN SPECIES #33OOO20 OH-
64.2 PERCENT BOUND IN SPECIES #9503301 Zn(OH)2 AQ
PERCENT BOUND IN SPECIES #9503302 Zn(OH)3
PERCENT BOUND IN SPECIES #9503303 Zn(OH)4 -2
EQUILIBRATED MASS DISTRIBUTION
IDX
NAME
DISSOLVED
MOL/KG PERCENT
95O Zn+2
ISO Cl-1
5OO Na+1
330 H+l
2 H2O
3.073E-02
6.178E-02
4.368E-03
-3.967E-06
7.065E-02
10O.O
100.0
10O.O
1OO.O
1OO.O
O.OOOE-t-00
O.OOOE+OO
O.OOOE+OO
O.OOOE-i-OO
O.OOOE-i-OO
SORBED
MOL/KG PERCENT
0.0
0.0
0.0
0.0
O.O
PRECIPITATED
MOL/KG PERCENT
O.OOOE+OO
O.OOOE+OO
O.OOOE+00
O.OOOE+OO
O.OOOE+OO
0.0
0.0
O.O
0.0
0.0
CHARGE BALANCE: SPECIATED
SUM OF CATIONS = 7.5O4E-O2 SUM OF ANIONS
0
O
CATIONS)
0 NONCARBONATE ALKALINITY =
0 IONIC STRENGTH = : 7.324E-02
1
7.10OE-02
PERCENT DIFFERENCE = 2.767E+OO (ANIONS - CATIONS) / (ANIONS •*•
1.082E-O3
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/24/89
TIME: 16:48:38
OSaturation indices and
0 ID # NAME
each component
415000O HALITE
4195000 ZNCL2
20950OO ZN(OH)2
2095OO1 ZN(OH)2 (C)
2095002 ZN(OH)2
2095OO3 ZN(OH)2
2095OO4 ZN(OH)2
4195O01 ZN2(OH)3CL
l.OOO)18O
41950O2 ZN5(OH)8CL2
2.OOO)180
20950O5 ZNO(ACTIVE)
2O95O06 ZINCITE
stoichiometry of all minerals
Sat. Index Stoichiometry (in parentheses) of
2.000) 2
2.OOO) 2
2.000) 2
2.000) 2
2.OOO) 2
3.OOO) 2
8.OOO) 2
l.OOO) 2
1.000) 2
(A)
(C)
(B)
(G)
(E)
CL
CL2
VE)
-5.356
-16.257
2.812
3.062
3.512
3.552
3.762
3.08O
13.322
3.953
4.123
( 1.0OO)5OO (
( l.OOO) 950 (
( -2.000)330 1
( -2.000)330 |
( -2.000)330 |
( -2.OOOJ33O I
( -2.000)330 1
( -3.000)330 1
( -8.0OO)33O 1
( -2.000)330 I
( -2.000)330 1
; i.ooo) iBo
; 2.000)180
; 1.000)950
; 1.000)950
; l.OOO)95O
[ 1.000)950
[ 1.0OO)95O
[ 2.0OO)95O
; 5.000)950
[ l.OOO) 950
[ 1.000)950
116
-------
APPENDIX D
ZINC/CADMIUM DATA
117
-------
ZINC/CADMIUM ESD TEST
Tot
1
1 IC-I
1 IC-I
1 IC-C
1 U-ll
1 IC-12
Ilituet
IctiMi
lleetrriei
ii.
l.S
l.S
4.5
4 S
I.I
Telt
Tin
Ir.
Ill
IH
111
111
111
loltiie
l/li.
l.S - 25.)
l.S • HI
IS - 2S.1
is • n .1
l.S • >S.l
lurm
llK
-------
APPENDIX E
GEOCHEMICAL CALCULATION
FOR ZINC CADMIUM SOIL
119
-------
Zinc and Cadmium at pH 7 (pg 1)
C'C VERSION: MINTEOA2 DATE OF CALCULATIONS: 08/22/8? TIME: 13:12:44
Zinc and Cadmium Solubility and Percent Distribution with Acetate at pH 7
Temperature (Celsius): 25.CO
Units o.f concentration: PPM
Ionic strength to be computed.
Carbonate concentration represents carbonate Alkalinity.
Do not automatical Iv terminate .if charge imbalance exceeds 30/C
Precipitation is allowed only for those solids specified as ALLOWED
in the input file (if any). ~
The maximum number of iterations is: 100
The method used to compute activity coefficients is: Debye-Huckel equation
Do not print the full species database including gram-f or.r.ula weights and
Debye-Huckel parameters.
950 0.iOOE+Od -1.32
160 0.10OE+04 -2.05
180 0.200E+04 -1.25
992 0.1OOE+O4 -1.77
500 0.335E-I-03 -1. 73
330 0.101E-04 -7.00
H2O HAS BEEN INSERTED AS A COMPONENT
3 1
330 7.OOOO 0.OOOO
INPUT DATA BEFORE TYPE MODIFICATIONS
ID NAME ACTIVITY GUESS LOG GUESS ANAL TOTAL
MEi
0
0
0
0
0
950
160
ISO
792.
500
330
2
ID
K/LOGK
95O
.0000
160
.0000
ISO
.Oooo
99Z
.OOOO
500
.0000
Zn+2.
Cd+2
Cl-l
Acetate
NA^i
H+l
H2Q
NAME
DIFF FXN
lrv-2
O.OOQE+00
Cd+2
O.OOQE+00
Cl-l
O.OOOE+00
Oc@ta.te
o. OQQE-'-OO
fxfa-i-i
0 • 000- *OO
1.514E-02
8.913E-03
5 . 623E— 02
1 . 67SE-02
1 . oiOE-02
1 . OOOE-O7
1 . OOOE+-00
ANAL MOL CALC MOL
1.000E+O3 O.OOOE-^-OO
l.OOO£-*-03 O.OO\)E+00
2. OOOE+03 O.OOOE+OO
l.OOOE+03 C.OOOE+OO
3.650E+O2 O.OOOE+OO
-1.320
-1.050
-1.25O
-1.770
-1.730
-7.000
0.000
ACTIVITY
1.514E-02
S.913E-03
5. 623E-02
1 . 693E-O2
1 . 660E-02.
l.OOOE-t-03
1 .OOOE+03
2 . OOOE+03
1 . OOOE+O3
3.350E*O2
1.00SE-O5
O.OOOE-t-OO
LOG ACTVTY
-1.S20OO
-2.050OO
-1.25000
-1.77000
-1.73000
GAM^A
1 . CX3QOOO
1. OOOOOO
1 . OOOOOO
l.OOOCOO
1 . OOOOOO
120
-------
Zinc and Cadmium at pH 7 (pg 2)
9509921 ZN ACETATE
0. OOO
9509922 ZN ACETATE2
0.000
9509923 ZNACETATE3
0.000
1.310E-03 0.0010387
7.302E-05 O.OOO0743
4.430E-O7 O.OOOOO04
0 • SPECIES: TYPE III - FIXED SOLIDS
O ID NAME CALC MQL LOG MOL
2 H20 -1.796E-O4 -3.746
330 H+i 1.155E-04 -3.938
-2.98352 0.792691
-4.12899 1.017559
-6.45447 0.792691
NEW LOCK DH
O.OO1 O.OOO
7.OOO 0.OOO
1.311
2.002
1.731
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/22/89
TIME: 13:13:18
PERCENTAGE DISTRIBUTION OF COMPONENTS AMONG
species
dissolved and adsorbed
+Cd+2
+C1-1
••-Acetate
85.0 PERCENT BOUND IN SPECIES # 95O
4.9 PERCENT BOUND IN SPECIES #95O180O ZnCl +
8.5 PERCENT BOUND IN SPECIES #9509921 ZN ACETATE
29.1 PERCENT BOUND IN SPECIES # 160
53.5 PERCENT BOUND IN SPECIES #16O180O CdCl +
6.7 PERCENT BOUND IN SPECIES #1601801 CdC12 AQ
8.2 PERCENT BOUND IN SPECIES #1609921 CD ACETATE
2.0 PERCENT BOUND IN SPECIES #1609922 CdACETATE2
87.8 PERCENT BOUND IN SPECIES # 18O Cl-1
1.3 PERCENT BOUND IN SPECIES #95O18OO ZnCl +•
8.4 PERCENT BOUND IN SPECIES #16O18OO CdCl +
2.1 PERCENT BOUND IN SPECIES #16O18O1 CdC12 AQ
84.0
PERCENT BOUND IN SPECIES #
992
Acetate
121
-------
Z1nc and Cadmium at pH 7 (pg 3)
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/22/89
TIME: 13sl3:19
OSaturation indices and
0 ID * NAME
component
4150OOO HALITE
4195000 ZNCL2
2W50OO ZN(OH)2 (A)
2095001 ZN(OH)2 (C)
20950O2 ZN(OH)2 (B)
2095003 ZN(OH)2 (G)
20950O4 ZN(OH)2 (E)
4195001 ZN2(OH)3CL
1.000)180
4195002 ZN5(OH)8CL2
2.000)180
2095005 ZNO(ACTIVE)
2095006 ZINCITE
4116OOO CDCL2
4116O01 CDCL2, 1H20
4116002 CDCL2.2.5H20
2016000 CD(OH)2 (A)
2016001 CD(OH)2 (C)
4116003 CDOHCL
1.000)180
2016002 MONTEPONITE
stoichiometry of all minerals
Sat. Index Stoichiometry (in parentheses) of each
-4.868
-12.103
-0 . 700
-O.450
0 . 000 "
0 . 040
0.250
-O .111
3.428
0.441
0.611
-5.133
-4.104
-3.875
-2 . 720
-2.640
-0 . 922
( 1 . OOO ) 50O (
( 1.000)950 (
( -2.000)330 (
( -2.000)330 (
( -2.000)330 (
( -2.000)330 (
( -2.000)330 (
( -3.000)330 (
( -8.000)330 (
( -2.000)330 (
( -2.000)330 (
( 1. OOO) 160 (
( 1.000)160 (
( 1.000)160 (
( -2.000)330 (
( -2 . 000 ) 33O (
( -1.000)330 (
i.ooo)iao
2.000)180
1.000)950 1
1.000)950 I
1.000)950 1
i.OOO)95O 1
1.000)950 I
2.000)950 1
5.0OO)95O 1
1. OOO) 9 50 1
i.OOO)95O 1
2.000)180
2. OOO) ISO I
2.000)180 1
1.000)160 i
1.000)160 1
1.000)160 i
[ 2 . OOO )
[ 2.000)
[ 2 . OOO )
[ 2.000)
[ 2 . OOO )
[ 3.000)
[ 8 . 000 )
[ 1 . OOO )
( 1 . OOO )
[ 1 . 000 )
[ 2 . 50O )
( 2. . 000 )
[ 2 . OOO )
( 1 . OOO )
2
2
2
2
^
2
2
2
2
2
2
2
2
2
-4.109
( -2.000)330 ( 1.0OO)16O ( l.OOO) 2
122
-------
Zinc and Cadmium at pH 8 (pg 1)
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/22/89 TIME:
11:43:35
Zinc and Cadmium Solubility and Percent Distribution with Acetate at pH 8
Temperature (Celsius): 25.OO
Units of concentration: PPM
Ionic strength to be computed.
Carbonate concentration represents carbonate alkalinity.
Do not automatically terminate if charge imbalance exceeds 30V.
Precipitation is allowed only for those solids specified as ALLOWED
in the input file (if any).
The maximum number of iterations is: 100
The method used to compute activity coefficients is: Debye-Huckel
equation
Do not print the full species database including gram-formula weights and
Debye-Huckel parameters.
950
160
180
992
50O
330
O H20 HAS
3 1
330
0INPUT
,10OE+04
. 100E+04
,200E+04
.10OE+04
, 38SE+03
0.101E-04
-1
__*•>
-1
-1
-1
-a
,82
.05
,25
.77
,78
.00
BEEN INSERTED AS A COMPONENT
0 ID
95O
16O
ISO
992
5OO
330
•2.
O ID
GAMMA
950
1.000000
160
1.OOOOOO
8.0000
DATA BEFCRE TYPE
NAME
Zn+2
Cd+2
Cl-1
Acetate
Na + 1
H-t-1
H20
NAME
NEW LOCK
Zn+2
O.OOOO
Cd-i-2
0.OOOO
LOG GUESS ANAL TOTAL
o.oooo
MODIFICATIONS
ACTIVITY GUESS
1.514E-02
8.913E-03
5.623E-02
1.698E-O2
1.660E-02
1.OOOE-OO
1.WOE+OO
ANAL MOL CALC MOL
DIFF FXN
1.0OOE+O3 O.OOOE+00 1.514E-02
O.OOOE+00
l.OOOE-t-03 O.OOOE+00 8.913E-03
O.OOOE*OO
1.820
2.050
1.250
1.770
•1.780
•B.OOO
O . OOO
i.OOOE+03
1 . OOOE+03
2.0OOE+03
1 . OOOE+03
3.8SOE-t-02
1.O08E-05
0 . OOOE-KDO
ACTIVITY LOG ACTVTY
-1.8200O
. 05OOO
123
-------
Z1nc and Cadmium at pH 8 (pg 2)
1609922
3.143
1609923
2.269
16O9924
2.438
9509921
1.309
9509922
2.003
95O9923
1.729
CdACETATE2
0. OOO
CdACETATE3
0. OOO
CdACETATE4
0. OOO
ZN ACETATE
0.000
ZN ACETATE2
0.000
ZNACETATE3
0. OOO
0 SPECIES: TYPE
0 ID NAME
2 H20
330 H+l
II
1.B77E-04 O.OOO19O9
2.895E-07 O.OOOO002
4.914E-O9 O.OOOOOOO
1.182E-03 0.0009403
6.723E-05 0.0000684
4 . 1 28E-O7 O . OOOOOO3
I - FIXED SOLIDS
CALC MOL LOG MOL
-2.730E-03 -2.564
2.724E-03 -2.565
-3.71925
-6.63772
-8.70620
-3.02674
-4.16522
-6.48369
1.016802
0.795396
0.40O251
O.795396
1.016802
O.795396
NEW LOGK DH
O.OO1 O.OOO
8.OOO 0.OOO
PC VERSION: MINTEQA2
11:44:08
DATE OF CALCULATIONS: 08/22/89
TIME:
PERCENTAGE DISTRIBUTION OF COMPONENTS AMONG
adsorbed species
dissolved and
-»-Cd+2
74.8 PERCENT BOUND IN SPECIES # 950 Zn+2
PERCENT BOUND IN SPECIES #95018OO ZnCl +•
4.5 PERCENT BOUND IN SPECIES #95033OO ZnOH +
4.0 PERCENT BOUND IN SPECIES #9503301 Zn(OH)2 AQ
4.1 PERCENT BOUND IN SPECIES #9501804 ZnOHCl AQ
7.7 PERCENT BOUND IN SPECIES #9509921 ZN ACETATE
28.4 PERCENT BOUND IN SPECIES # 16O Cd+2
52.A PERCENT BOUND IN SPECIES #16018OO CdCl +
6.6 PERCENT BOUND IN SPECIES #16O18O1 CdC12 AQ
1.7 PERCENT BOUND IN SPECIES #1601803 CdOHCl AQ
8.3 PERCENT BOUND IN SPECIES #1609921 CD ACETATE
PERCENT BOUND IN SPECIES #1609922 CdACETATE2
124
-------
Z1nc and Cadmium at pH 8 (pg 3)
o
CHARGE BALANCE: SPECIATED
SUM OF CATIONS = 5.282E-02 SUM OF ANIONS
0
0 PERCENT DIFFERENCE =
CATIONS)
O NONCARBONATE ALKALINITY =
0 IONIC STRENGTH = : 7.236E-02
1
6.380E-02
9.417E+00 (ANIONS - CATIONS)/(ANIONS
1.277E-06
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: O8/22/89
TIME: 11:44:09
OSaturation indices and
O ID * NAME
component
415OOOO HALITE
4193000 ZNCL2
2095OOO ZN(OH)2 (A)
2095001 ZN(OH)2 (C)
2095OO2 ZN(OH)2 (B)
2095003 ZN(OH)2 (G)
2095004 ZN(OH)2 (E)
4195OO1 ZN2(OH)3CL
1.000)180
4195O02 ZN5(OH)8CL2
2.000)180
2095005 ZNO(ACTIVE)
2095006 ZINCITE
4116000 CDCL2
41160O1 CDCL2, 1H20
4116O02 CDCL2,2.5H20
2016000 CD(OH)2 (A)
2016O01 CD(OH)2 (C)
4116003 CDOHCL
1.000)180
2016002 MONTEPONITE
stoichiometry of all minerals
Sat. Index Stoichiometry
-4.869
-12.158
.250
. 3OO
,95O
. 990
in parentheses) of each
2OO
2.786
11.172
2.391
2.561
-5.142
-4.113
-3.884
-0.724
-O.644
0.072
-2.113
( 1 . 000 ) 50O (
( 1.000)950 (
( -2.000)330 (
( -2.000)330 (
( -2.000)330 (
( -2.000)330 (
( -2.000)330 (
( -3.000)330 (
( -8.000)330 (
( -2.000)330 (
( -2.000)330 (
( 1.000)160 (
( 1.000)160 (
( 1.0OO)16O (
( -2.000)330 (
( -2.000)330 (
( -l.OOO)330 (
( -2.000)330 (
1.0OO)18O
2.000)180
1.0OO)95O (
1.000)950 (
1. OOO) 950
1 . OOO ) 950 (
1.0OO)95O
2.000)950 (
5.000)950
1.000)950 (
1.000)950 (
2.0OOU8O
2.000)180
2.000)180
1.000)160
1.000)160
1.000)160
l.OOO)16O
2 . 000 )
2.000)
2 . OOO )
2. OOO)
2 . OOO )
3 . 000 )
8.000)
1 . OOO )
1.000)
1 . 000 )
2 . 500 )
2 . OOO )
2 . 000 )
1 . 000 )
1 . OOO )
'2
2
2
2
2
2
"2
2
2
2
2
2
2
2
2
125
-------
Z1nc and Cadmium at pH 9 (pg 1)
PC VERSION: MINTEDA2 DATE OF CALCULATIONS.- 08/22/89
TIMEs 13:iOt06
Z1nc and Cadmium Solubility and Percent Distribution with Acetate at pH 9
Temperature (Celsius): 25.OO
Units of concentration: PPM
Ionic strength to be computed.
Carbonate concentration represents carbonate alkalinity.
Do not automatically terminate if charge imbalance exceeds 30'/.
Precipitation is allowed only for those solids specified as ALLOWED
in the input file (if any).
The maximum number of iterations is: 100
The method used to compute activity coefficients is: Debye-Huckel equation
Do not print the full species database including gram-formula Heights and
Debye-Huckel parameters.
950
16O
180
992
500
330
0.100E+04
0.100E-«-04
0 . 200E+04
0.100E+04
0.385E+03
0.101E-04
-1.82
-2.05
-1.25
-1.77
-1.78
-9 . OO
0 H20 HAS BEEN INSERTED AS A COMPONENT
3 1
330 9.0000 0.OOOO
0INPUT DATA DEFORE TYPE MODIFICATIONS
O ID
950
16O
180
992
500
330
2
0 ID
NEW LOCK
95O
0.0000
160
0 . OOOO
180
0 . OOOO
992
0 . OOOO
500
0 . OOOO
NAME
Zn+2
Cd+2
Cl-1
Acetate
Na-M
H+l
H20
NAME
DIFF FXN
Zn>2
O.OOOE+OO
CcJ>2
0. OOOE +00
Cl-1
0. OOOE+00
Acetate
0. OOOE* 00
NaU
0. OOOE +OO
ACTIVITY GUESS LOG GUESS ANAL TOTAL
1.514E-02
8.913E-03
5 . 623E-02
1 . 690E-O2
1.660E-02
1 . OOOE-^9
1. OOOE +00
ANAL MOL CALC MOL
1 . OOOE + 03 0 . OOOE-* OO
1 . OOOE> O3 O . OOOE+OO
2 . OOOE+03 O . OOOE +OO
1 . OOOE+03 0 . OOOE+OO
3 . 850E+O2 O . OOOE+OO
-1.820
-2.050
-1.250
-1 . 770
-1.780
-9 . 000
U . OOO
ACTIVITY
1.514E-02
8.913E-03
5.623E-02
1 . 698E-O2
1 . 66OE-02
1 . OOOE+03
1 . OOOE+03
2 . OOOE+O3
1 . OOOE+03
3.850E+02
1.008E-05
0 . OOOE+OO
LOG ACTVTY
-1.82OOO
-2.05OOO
-1.250OO
-1.77000
-1.78OOO
GAMMA
l.OOOOOO
l.OOOOOO
l.OOOOOO
l.OOOOOO
1.OOOOOO
126
-------
Z1nc and Cadmium at pH 9 (pg 2)
9509921 IN ACETATE
0. OOO
9509922 ZN ACETATE2
0.000
9509923 ZNACETATE3
O.OOO
2.208E-04 O.OOO1B03
1.429E-05 0.0000145
9.389E-08 0.0000001
0 SPECIES: TYPE III - FIXED SOLIDS
O ID NAME CALC MOL LOG MOL
2 H20 -2.561E-02 -1.592
330 H+1 2.561E-02 -1.592
1
-3.74407
-4.B39BO
-7.11553
0.816306
1.011920
O.B163O6
NEW LOOK DH
O.OO1 O.OOO
9 . OOO 0. OOO
1.298
2.005
1.718
PC VERSION: MINTEQA2 DATE OF CALCULATIONS: 08/22/89
TIME: 13:10:39
PERCENTAGE DISTRIBUTION OF COMPONENTS AMONG
species
dissolved and adsorbed
+ZO+2
11.9 PERCENT
7. A PERCENT
PERCENT
PERCENT
PERCENT
PERCENT
45.5 PERCENT
6.0 PERCENT
1.0 PERCENT
PERCENT
7.7 PERCENT
2.2 PERCENT
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
BOUND
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
SPECIES
# 950
#9503300
#9503301
#9501804
#9509921
# 160
#1601800
#1601801
#1603300
#1601803
#1609921
#1609922
Zn+2
ZnOH +
Zn(OH)
ZnOHCl
2 AQ
AQ
ZN ACETATE
Cd+2
CdCl +
CdC12
CdOH +
CdOHCl
AQ
AQ
CD ACETATE
CdACETATE2
•••Cl-i
86.3 PERCENT BOUND IN SPECIES # 1BO Cl-1
PERCENT BOUND IN SPECIES #9501804 ZnOHCl AQ
127
------- |