»'
Office of gtnargarjGy and - Office of
Retrial Response « ' Re$e§ir«Qh
(^ 00 20460 ,
May 1QS7
v>EPA
ngimgnng
Teah nplpgy
for th0 lm&diatlon of
Soil
Purpose
Section 121(b) of the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA), man-
dates the U.S. Environmental Protection Agency (EPA) to
select remedies that "utilize permanent solutions and alter-
native treatment technologies or resource recovery tech-
nologies to the maximum extent practical" and to prefer
remedial actions in which treatment "permanently and sig-
nificantly reduces the volume, toxicity, or mobility of hazard-
ous substances, pollutants, and contaminants as a principal
element." The Engineering Bulletins are a series of docu-
ments that summarize the latest information available on
selected treatment and site remediation technologies and
related issues. They provide summaries of and references
for the latest information to help remedial project managers,
on-scene coordinators, contractors, and other site cleanup
managers understand the type of data and site characteris-
tics needed to evaluate a technology or technologies for
potential applicability to their Superfund or other hazardous
waste site. Those documents that describe individual treat-
ment technologies focus on remedial investigation scoping
needs. Addenda will be issued periodically to update the
original bulletins.
Abstract
Pesticide contamination includes a wide variety of com-
pounds and may result from manufacturing improper stor-
age, handling, disposal; or agricultural processes. It can
occur in soil and can lead to secondary contamination of
groundwater. Remediation of pesticide-contaminated soils
can be a complicated process, as most pesticides are
mixtures of different compounds rather than pure pesticide.
The remedial manager is faced with the task of selecting
remedial options that will meet established cleanup levels.
There are three principal options for dealing with pesticide
contamination: containment/immobilization, destruction,
and separation/concentration. This bulletin focuses on soils
and current or soon-to-be available separation/concentra-
tion pesticide remediation technologies. The information
presented is condensed from the technical resource docu-
ment "Contaminants and Remedial Options at Pesticide
Sites" [1] and other available literature. Technologies that
have not produced performance data are not included nor
are water, sludge, or sediment treatment technologies. The
resource document contains site-specific information on
pesticide contamination and the remediation techniques
used.
Background
Pesticides, as defined by the U.S. Federal Environmen-
tal Pesticide Control Act, are "...any substance or mixture of
substances intended for preventing, destroying, repelling,
or mitigating any insect, rodent, nematode, fungus, weed or
any other form of terrestrial or aquatic plant, animal life, or
virus, bacteria or other microorganism which the Adminis-
trator declares a pest" [2]. Pesticides include insecticides,
fungicides, herbicides, acaricides, nematocides and roden-
ticides as well as any substance or mixture of substances
intended for use as a plant regulator, defoliant or desiccant.
Pesticides do not include such substances as fertilizers or
veterinary medicines [1]. The EPA has developed extensive
data on specific pesticide products and wastes through the
pesticide registration program and site investigation [3,4,5].
Pesticide wastes are generally complex chemical mix-
tures and not pure pesticides. These mixtures can include
solvents, carriers and other components that will have a
direct effect on toxicity, mobility, transport and treatment.
The resource document categorizes pesticides into
four waste groups based on available treatment technolo-
gies [1]. The four waste group categories are:
WG01 - Inorganic pesticides
WG02 - Halogenated water insoluble organics
WG03 - Halogenated sparingly water soluble organics
and organo-linked compounds
WG04 - Nonhalogenated organics and organo-linked
compounds.
Table 1 details the four pesticide waste groups and
gives examples of commonly found pesticides. These
groups are subdivided further to show the chemical class or
indicate references
Printed on Recycled Paper
-------
Tablo 1. Pesticide Chemical Waste Groups." [1,6]
Postlckle Chemical
Waste Group
WQ01 - Inorganics
WG02 - Halogenated water
insoluble organics
WG03- Halogenated
sparingly water soluble
organics and organo-
linkod compounds
WG04 - Nonhalogenated
organics and organo-linked
compounds
Family
Organochlorine/
DDT analog
DDT analog
uyciodiene
Hexachlorocyclohexane
Toxaphene
Nitrated aromatics
Nitrated aliphatics
Alkylmercaptan
Carboxamide
Triazine
Halogenated phenol
Halogenated volatile
aliphatics
Aryloxyalkanoic acid
Phosphorothioate
Dinitroaniline
Unsaturated aliphatics
Thiourea
Alkaloids
Carbamates
Phosphonates
Phosphorothioates
•The Bulletin covers only the technologies in bold. Discussions
Example
Lead arsenate
Sodium fluoride
Zinc phosphide
ODD
DDE
DDT
Methoxychlor
Alarm
Chlordane
Dieldrin
Endosulfan
Endrine
Heptachlor
a-BHC
/3-BHC
7- BHC (lindane)
Toxaphene
Pentachloro-
nitrobenzene
Chloropicrin
Captan
Alachlor
Pronamide
Cyanazine
Pentachlorophenol
(PGP)
Dibromochloropropane
(DBCP)
Ethylene dibromide
(EDB)
Methyl bromide
2,4-D
2,4,5-TP (silvex)
Methyl parathion
Trifluralin
Acrolein
Ethylene oxide
Ethylene thiourea (ETU)
Allethrin
Rotenone
Aldicarb
Benomyl
Carbaryl
Diazinon
Glyphosate
Dimethoate
Marathion
Parathion
Phorate
on the other technologies can
Applicable Soil Treatment
Technologies
Chemical oxidation
Soil flushing
Stabilization/Solidification
Soil washing
Incineration
Bioremediation
Dehalogenation/Hydrodehalo-
genation
Hydrolysis/Neutralization
Ultra high temperature processes
Soil flushing
Soil washing
Thermal desorption
Steam extraction
Solvent extraction
Supercritical CO2 extraction
Adsorption
Filtration
Chemical reduction
Chemical oxidation
Radio frequency heating
Incineration
Bioremediation
Dehalogenation/Hydrodehalo-
genation
Hydrolysis/Neutralization
Ultra high temperature processes
Soil flushing
Soil washing
Soil vapor extraction
Thermal desorption
Steam extraction
Solvent extraction
Supercritical CO2 extraction
Chemical oxidation
Adsorption
Filtration
Chemical reduction
Radio frequency heating
Incineration
Bioremediation
Hydrolysis/Neutralization
Ultra high temperature processes
Soil flushing
Soil washing
Thermal desorption
Steam extraction
Solvent extraction
Supercritical CO2 extraction
Chemical oxidation
Adsorption
Filtration
Chemical reduction
be found in the resource document.
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
family each pesticide belongs to according to their molecu-
lar structure or key functional group. Applicable treatment
technologies for each waste group are also provided. Ref-
erences to pesticides and pesticide wastes in this document
use the above waste group categories.
Most pesticides readily adsorb on soils because of their
high adsorption capacity. In fact, adsorption of pesticides
on the soil surface is a dominant factorthat affects the extent
of the site contamination. As a rule, when applied properly,
pesticides migrate slowly. Concentrated pesticide from a
spill or leak, however, can move more quickly into the
subsurface, especially if the pesticide is in aqueous phase
or under the influence of percolating water [1 ]. Mechanisms
of pesticide fate and transport that affect the extent of site
contamination include:
Adsorption on soils
Biodegradation
Volatilization
Downward migration
Lateral migration
Photolysis.
Selecting a remedial strategy includes considering the
individual contaminant's toxicity, persistence, migration
pathways and rate of transport from a site. The wide range
of physical and chemical properties of pesticides also influ-
ence the selection of an appropriate remedial technology or
combination of technologies (known as a treatment train). It
is important to gain information specific to the pesticide(s)
present in order to effectively identify the treatment
technology(ies) that is most applicable and cost effective.
Separation/Concentration Options
Treatment technologies or control options for pesti-
cides fall into three categories: containment/immobilization,
destruction and separation/concentration. This document
addresses the separation/concentration options.
Separation/concentration technologies primarily serve
to separate contaminants from soils, thereby concentrating
the waste stream and reducing the amount of material that
must be treated. These technologies are mainly used as a
pretreatment step, since no destruction or reduction of
toxicity is attained.
Separation/concentration technologies can be classi-
fied as follows:
• In situ technologies
- Soil flushing
- Soil vapor extraction (SVE)
- Steam extraction
- Radio frequency (RF) heating
• Ex situ technologies (excavated soils)
- Thermal desorption
- Soil washing
- Solvent extraction
- Supercritical CO2 extraction.
The decision to select and implement these techniques
rests primarily on the action levels established for the site.
Key issues for these technologies are the management,
treatment and disposal options for the process extract
phase. While not discussed in this bulletin, regulatory
compliance and disposal criteria for extract-phase materials
must be addressed.
Separation/concentration technologies can potentially
be applied to pesticide wastes in all four waste groups. Soil
flushing, SVE and steam extraction technologies have lim-
ited applicability to pesticide-contaminated soils, thus these
separation/concentration technologies are not discussed in
this document. In this bulletin, the following separation/
concentration technologies most applicable to pesticide-
contaminated soils are discussed:
- Radio frequency heating
- Thermal desorption
- Soil washing
- Solvent extraction
- Supercritical carbon dioxide (CO2) extraction.
For each separation/concentration option presented,
the following items are discussed:
Process description
Data needs for technology implementation
Technology performance in treating pesticides in soils
Process residuals (if available)
Site-specific regulatory requirements or goals (if avail-
able).
Radio Frequency Heating
Radio frequency (RF) heating is an in situsofi treatment
process that uses electromagnetic energy in the radio fre-
quency band to heat soil rapidly. During this process, the
contaminants are vaporized and/or boiled out along with
water vapor formed by the boiling action of native soil
moisture. The gases and vapors formed upon heating the
soil are recovered and treated on site. This combination of
vaporization, boiling, and steam stripping has been used
effectively in removing aldrin, dieldrin, endrin, isodrin (WG02)
and other pesticides that typically volatilize in the tempera-
ture range of 80°C to 300°C, such as volatile aliphatics
(WG03). This technology offers three distinct advantages:
• the contaminated materials do not need to be exca-
vated;
• the contaminants are removed from the soil as vapors
and can be subsequently trapped and treated in a vapor
treatment system (process equipment may be trailer
mounted and mobile);
• the presence of other contaminants such as jet fuel,
polychlorinated biphenyls (PCBs), creosote, petroleum
hydrocarbons, does not limit the treatment effective-
ness of the process [7,8,9].
Process Description
The RF soil decontamination process heats a defined
volume of soil in situ to temperatures of 80°C to 300°C by
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
means of an electrode array inserted in bore holes drilled
Into the soil. The process uses electromagnetic energy in
the frequency range of 2 to 13 megahertz to achieve high
soil temperatures. The actual frequency depends upon the
volume and depth of the treated soil and the dielectric
properties of the soil.
The electrodes, spaced evenly apart in the soil, are 2 to
15 ft long. The soil between the electrodes is heated by the
RF energy during treatment. Some of the electrodes are
perforated to serve as vapor collection lines which are
manifolded to a vapor treatment system [7,8,9].
Data Needs for Technology
Implementation
The data needs for RF heating are presented in
Table 2.
Performance
A field pilot demonstration of this technology was con-
ducted at the Rocky Mountain Arsenal. The pesticide-
contaminated soil was a mixture of clay and sand to a depth
of 12 feet and gravely sand to a 17-ft depth. The results are
summarized in Table 3. The initial concentrations shown
are the average of 36 samples at depths of 7 to 17 ft. The
final contaminant concentrations shown are averages in the
200-250°C, 250-300°C, and >300°C temperature ranges.
The contaminant removal percentage was greater than 98
percent.
The preliminary cleanup goals, set by EPA and state
agencies, were developed on a risk-based assessment of
10-6 biological worker exposure. Table 4 shows the final
pesticide concentrations in treated soil for each of the three
treatment temperature ranges, with the associated cleanup
goal for each pesticide. The data indicate that the best
Table 2. Data Needs for Radio Frequency Heating. [7,8]
Data Needs
Possible Effects
Type of soil
Presence of metal drums or metallic
debris
Type of contaminants(s)
Soil moisture content
Row rate and depth of groundwater
table
Low permeability soils increase costs and decrease contaminant recovery;
dielectric properties of soil determine RF power requirement
Disrupts current flow; may interfere with electode placement
Requires supplementation with other treatment methods if nonvolatile
contaminants (boiling points >300°C), heavy metals, or inorganic salts are
present
High moisture content increases energy requirements and impacts removal
efficiency of organic contaminants
Presence of fast moving groundwater in heated zone acts as an energy sink
and negatively impacts process cost; may require diversion of water from
heated zone by slurry walls, etc.
Table 3. Results of Radio Frequency Heating Pilot Test Program at Rocky Mountain Arsenal Over All Temperature
Ranges Tested". [7]
Pesticide
Initial Concentration (ppm) Final Concentration (ppm/ Percent Removal
Aldrin
DIeldrin
Endrin
Isodrin
1100
490
630
2000
11.3
3.2
2.8
33
99.0
99.3
99.6
98.4
a200-250°C, 250-300°C, and >300°C
Table 4. Rnal Concentrations of Compounds versus Soil Temperature in Radio Frequency Test at Rocky Mountain
Arsenal [9].
Pesticide
Aldrin
DIeldrin
Endrin
Isodrin
200-250°C
Concentration
(mg/kg)
0.97(±1.0)a
0.59 (±0.35)
1.7 (±2.0)
1.3 (NA)b
250-300°C
Concentration
(mg/kg)
31 (±40)
8.0 (±8.0)
5.6 (±5.3)
48 (±62)
>300°C
Concentration
(mg/kg)
1.8 (±3.1)
1.0 (±1.5)
1.1 (±1.5)
49 (±90)
Preliminary
Remediation Goal
(mg/kg)
0.56
0.40
17
3.6
"Values in parentheses represent the standard deviation of the concentration given
bNA s Not available
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
overall treatment was achieved in soils heated to between
200 and 250°C. In this temperature range removal of both
endrin and isodrin met the cleanup criteria [9].
Process Residuals
The vapors and gases collected by the second step of
the process require treatment, combustion and/or scrubbing
to remove acid gases. The condensed liquids from the
collection phase are separated into aqueous and organic
fractions. The aqueous phase is treated using activated
carbon and filtration. The organic phase is collected for
destruction at an approved facility [7,8,9].
Thermal Desorption
Thermal desorption is an innovative ex situ technology
which includes a broad range of processes using thermal
energy (e.g., heated air, infrared volatilization, laser-in-
duced desorption, etc.) to remove volatile and semivolatile
organic and inorganic compounds from contaminated soil.
Thermal desorption is applicable to pesticide waste
from waste groups WG02, WG03, and WG04. Toxicity is not
affected by thermal desorption; the toxic compounds are
removed from the soil for further treatment or disposal [1].
Process Description
Thermal desorption is used to desorb low, medium and
high boiling-point organic pesticides. Front-end material
handling steps such as excavation, dewatering and/or dredg-
ing are performed. High soil moisture content may require
greater energy usage, but it may also enhance volatilization
by producing steam within the media. The desorption units
typically require at least 20 to 30 percent solids by weight.
Some units can accept only 10 percent total organic carbon
loading by weight.
The media enters the desorber unit and is heated to
temperatures between 95 and 540°C. A temperature above
150°C may be required to effectively desorb medium-to-
high boiling point organic pesticides. The vapors generated
from the process can be destroyed/oxidized in an after-
burner. The afterburners operate in excess of 870°C and
have a fluid residence time sufficient to achieve a destruc-
tion efficiency greater than 99.99 percent.
The efficiency of thermal desorption is primarily depen-
dent on the bed temperature and residence time in the unit.
Residence time determines the soil treatment temperature
for a given airflow rate. The resulting air and soil tempera-
tures affect the rate and degree of contaminant desorption.
A temperature differential of approximately 95°C higher
than the boiling point of a pesticide is required to achieve
complete desorption and to overcome the intrinsic heat
transfer resistances present in the medium [1,11].
Data Needs for Technology
Implementation
The data needs are presented in Table 5.
Performance
Thermal desorption technology has been used in sev-
eral remedial actions including three Superfund sites. The
Low Temperature Thermal Aeration (LTTA) System is a
Table 5. Data Needs for Thermal Desorption. [12,13,14]
Data Needs
Possible Effects
Moisture content
Particle size distribution
Total solids content
PH
Contaminant concentrations
Presence of metals or inorganics
Volatile metals
Total chlorine
Total petroleum hydrocarbons
Vapor pressure
Boiling point
Adsorptive properties of contaminant
High moisture content (>20%) increases energy requirement; dewatering or
pretreatment may be required
Oversize (>1-1.5 in.) particles may require size reduction or screening;
presence of fine silt or clay may generate fugitive dust loading for air
pollution control equipment
Usually a minimum of 20-30% solids is required
Very high (>11) or low (<5) soil pH may result in corrosion of system
components
Total organic bonding is limited to approximately 10%; higher organic
bonding may result in incomplete processing
Are not likely to be treated effectively
May concentrate in off-gas and require additional treatment
May affect volatilization of some metals
High concentrations may require a thermal oxidizer or afterburner and a
quench tower for cooling
Affects removal effectiveness; high contaminant vapor pressure increases
removal efficiency and requires less energy for contaminant removal
Affects process temperature and removal effectiveness; low boiling point
reduces energy requirements for contaminant removal
Affects amount of energy required to desorb contaminant from soil particles
Engineering Bulletin: Separation/Concentration Technology Alternatives lor the Remediation of Pesticide-Contaminated Soil
-------
remedial system developed by Canonie Environmental Ser-
vices Corporation. The LTTA System thermally desorbs
organic compounds from contaminated soil without heating
the soil to combustion temperatures. The system performs
three main operations: soil treatment, emissions control
and process water treatment. LTTA systems can treat a
wide variety of soils having different moisture and contami-
nant concentrations, and can remove pesticides from soil to
below br near analytical detection limits [11].
The LTTA System was used in a full-scale Superfund
Innovative Technology Evaluation (SITE) demonstration
conducted at an abandoned pesticide mixing facility in
western Arizona. The facility stored and mixed several
pesticides including toxaphene, DDT, ODD, and DDE. The
Arizona pesticide site was remediated under supervision of
the slate by voluntary action of the potentially responsible
party. All treated soils at the site were required to contain
less than 5 mg/kg total pesticide after one pass through the
LTTA system, as stated in the remedial action plan. An
estimated 51,000 tons of contaminated soil required treat-
ment. Sliding scale cleanup criteria were established,
shown in Table 6, with a maximum allowable concentration
of 1.09 mg/kg of toxaphene with no DDT/DDD/DDE (com-
bined) at one end, and a maximum allowable concentration
of 3.53 mg/kg DDT/DDD/DDE with no toxaphene at the
other end. Treated soils met the specific cleanup criteria if
90 percent of the treated soil fell within the cleanup criteria
on a daily basis.
The LTTA SITE demonstration consisted of three sepa-
rate runs, each requiring about 8 hr to complete. Based on
site characterization data of the contaminant distribution,
the soil was treated to a depth of 2 ft. This soil was primarily
clay-like in nature (40 percent fines).
Table 6. Sliding Scale Cleanup Criteria Concentrations for Pesticides During the LTTA™ SITE Demonstration of
Thermal Desorption [14].
DDT/DDD/DDE (mq/kg) 0.00
0.01
0.83
1.00
2.00
3.00
3.36
3.52
Toxaphene (mg/kg)
1.09
1.087
0.83
0.78
0.47
0.16
0.05
0.00
Table 7. Pesticide Concentrations and Removal Efficiencies in LTTA™ SITE Demonstration of Thermal Desorption
Technology. [14]
Pesticide
Toxaphene
DDT
ODD
DDE
Cone.
Range in
Feed Soil,
mg/kg
4.5 to 47
1.2 to 54
0.027 to 0.86
3.7 to 15
Average3 Concentration.
Run 1
Feed
Soil
27.5
24.1
0.34
7.1
Treated
Soil
<0.017
<0.001
<0.0003
1.1
Run 2
Feed
Soil
16.5
22.8
0.12
8.3
Treated
Soil
0.017
0.001
<0.0003
0.97
, mg/kg
Run 3
Feed
Soil
10.8
9.3
0.2
5.1
Treated
Soil
<0.025
0.002
<0.001
0.28
Removal, %
Run 1
>99.9
>99.9
>99.9
90.2
Run 2
>99.9
99.9
>99.7
88.4
Run 3
>99.8
99.9
>99.8
93.3
•"Average of four composite samples for each feed or treated soil value
Demonstration results, shown in Table 7, indicate toxa-
phene, DDT, ODD, and DDE removals in excess of 99
percent for each of the three runs. The remedial cleanup
criteria were met during each of the runs [11,14].
Williams Environmental Services (WILLIAMS) com-
pleted a treatability study using the WILLIAMS thermal
dosorption system for a removal action at a former pesticide
formulation site (T H Agriculture and Nutrition Company) in
Albany, GA. The removal action, which included treatment
of approximately 3,000 tons of soil contaminated with over
1,000 mg/kg total pesticides, was overseen by EPA and the
Georgia Department of Natural Resources Environmental
Protection Division. Treatability study results showed that
at a soil treatment temperature of 500°F, total pesticide
removal ranged from 86 to 93 percent; when operated at a
treatment temperature of 700°F, pesticide removal was
more than 99 percent. At 700°F, the total pesticide concen-
tration was reduced from about 200 mg/kg to less than 0.003
mg/kg [15].
Process Residuals
This innovative technology produces the following three
residual streams:
• Decontaminated soil, sludge or sediment
• Scrubber water from the air pollution control system
• Off-gas emissions from the air pollution control system
[1]-
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
The decontaminated media may be reclaimed after
analysis. The scrubber water can be treated onsite or
discharged to a publicly-owned treatment works (POTW).
Off-gas emissions may require additional air pollution con-
trol before being released through a stack [1].
Soil Washing
Soil washing is an innovative ex situ technology which
uses an aqueous solution to decontaminate soils. Contami-
nant removal or volume reduction is achieved by one or
more of the following mechanisms: 1) the contaminants are
suspended or dissolved in the wash solution, 2) the con-
taminants are concentrated by segregating the most con-
taminated fraction from the bulk of the soil using size-
separation techniques or 3) the contaminants are concen-
trated by segregating dense, paniculate contaminants
through the use of density-separation techniques
[16,17,18,19,20,21]. Each of the four pesticide chemical
waste groups (Table 1) can potentially be treated using the
soil washing technology [1].
Process Description
Soil washing systems consist of specific unit operations
(subsystems) that are tailored to accommodate the site
conditions and soil characteristics. In general, soil washing
systems consist of three types of subsystems:
• feedstock preparation
• soil washing
• residuals treatment.
Feedstock preparation includes excavation, transpor-
tation of the soil to the soil-washing staging area, removal of
debris and separation of the soil into different particle-size
or density fractions. Typical post-excavation operations
include screening, crushing and attrition scrubbing. The
purpose of feedstock preparation is to segregate the soil
components into fractions based on contamination levels.
Minimally contaminated soils, requiring little or no treat-
ment, can be returned to the site as backfill, but highly
contaminated fractions require more aggressive treatment.
Reducing the volume of soil passing through the remainder
of the system increases the cost-effectiveness of the tech-
nology [16,17,18,19,20,21].
Soil washing unit operations tend to fall into two catego-
ries: physical separation of the soil matrix into different
particle-size or density fractions, and chemical separation
of the contaminants from the soil matrix. Organic contami-
nants such as pesticides are often concentrated in the fines
(e.g., clays and silt). Physical separation of this fraction
using unit operations such as flotation, gravity settling,
hydrocloning, washing and rinsing achieves further volume
reduction [16,17,18,19,20,21]. Chemical separation trans-
fers the contaminant from the soil matrix to the aqueous-
phase wash solution. Chemical separation can be en-
hanced by optimizing process conditions. Increased wash
or rinse temperature, addition of surfactant and pH adjust-
ment may enhance pesticide removal [16,17,18,19,20,21].
Residuals treatment subsystems include unit opera-
tions that treat process water, air emissions and highly
contaminated fractions of the soil, such as the fines. The
unit operations typically include biological, chemical or ther-
mal oxidation units for destruction of residual contamina-
tion, as well as adsorption processes to further concentrate
the contaminants.
Data Needs for Technology
Implementation
Data needs for soil washing are presented in Table 8.
Table 8. Data Needs for Soil Washing. [21,22]
Data Needs
Possible Effects
Particle size distribution
Soil type
Complex waste mixtures
Wash solution
Metal content
Organic content
Partition coefficient
pH, buffering capacity
Affects efficiency of removal from wash liquid; particles >2 inches in diameter
require pretreatment for oversized particles; particles <0.063 mm in diameter
are difficult to wash
Affects pretreatment and transfer requirements; high clay and silt levels
make it difficult to remove contaminants because of their strong adsorption to
the particles
Increases difficulty in formulating suitable washing fluid; solubility of different
contaminants may vary
Presence of surfactants or other reagents in wash solution may cause
difficulties in wastewater and sludge treatment/disposal
Concentrations and species affect selection of wash fluid, mobility of metals,
and post-treatment
Concentration and species affect selection of wash fluid, contaminant
mobility and post-treatment
High coefficient requires excessive volumes of wash fluid since contaminant
is tightly bound
Can affect pretreatment requirements, wash fluid selection, and choice of
materials of construction for equipment
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
Performance
Soil washing is an innovative technology available for
full-scale implementation. It has been used as a remediation
technology at several Superfund sites [23]. A pilot-scale
soil-washing treatability study was conducted on pesticide-
contaminated soil at the Sand Creek Superfund site in
Commerce City, CO. The treatability study consisted of 23
individual runs conducted under varying process condi-
tions. The process variables tested included:
• depth of soil excavation
• surfactant type and concentration
* wash water temperature
• pH
• number of washes
• liquid-to-solids ratio.
Table 9 provides a summary of the treatability study
results. Experimental conditions and results of the indi-
vidual runs are shown in Table 10.
Control runs using only ambient-temperature munici-
pal water without surfactants addition demonstrated re-
moval of 76 to 81 percent dieldrin and 67 to 81 percent
heptachlor from the coarse soil fraction. Results indicate
that surfactant addition had a positive influence on pesti-
cide removal [24,25].
Table 9. Summary of Sand Creek Superfund Site Soil Washing Treatability Study Results [24].
Soil Fraction
Feed
Treated Coarse
Treated Rnes
Concentration (mg/kg)
Dieldrin Heptachlor
2.7 to 27 8 to 460
0.0 to 6.8 1.4 to 50
0.0 to 37 4.4 to 340
Removal (%)
Dieldrin Heptachlor
NAa MA
-44 to 91 17 to 99
-131 to 86 -100 to 97
BNA « Not applicable
Table 10. Sand Creek Superfund Site Soil Washing Treatability Study Results'[24].
Test Conditions
Run #
1
2
11
12
6
7
23
3
8
9
10
17
4
5
18
18A
19
19A
20
20A'
21
22
13
14
15
16
Surfactant Temp.
none
none
none
none
0.4A
LOA
LOA
0.4S
LOS
LOS
0.4S
0.4S
0.4T
0.5T
LOT
LOT
L5T
L5T
LOT
LOT
1.0M
LOM
LOS
LOT
LOT
LOS
ambient
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
130
pH Soil Depth
(feet)
7
10
10
7
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
7
10
10
10
10
10
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
0-1
1-3
1-3
0-5
0-5
Liq./ Soil
Ratio
6:1
6:1
(9:1)
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
6:1
(9:1)
(9:1)
6:1
6:1
6:1
6:1
6:1
6:1
Heptachlor
(mg/kg)
Feed
Soil
220
87
150
170
180
230
230
100
200
270
260
22
220
220
120
120
250
250
64
64
460
210
63
120
8
12
Treated
Soil
50
29
37
34
26
25
15
24
36
28
34
12
27
30
16
18
16
20
12
14
16
22
19
1.8
2.0
<1.6
Dieldrin
(mg/kg)
Feed
Soil
19
16
24
23
17
18
18
19
17
27
25
2.8
18
20
13
16
18
18
19
19
20
17
9.7
17
2.7
3.4
Treated
Soil
4.6
2.4
4.5
4.5
6.8
2.9
5.6
2.0
4.4
3.9
4.9
1.5
5.0
5.0
1.7
1.8
3.2
2.0
1.9
1.6
2.6
3.8
1.9
2.2
<1.6
<1.6
A s Adsee; S = SDS; T = Tergitol; M = SDS/Tergitol mix
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
The site cleanup criteria, established in the Record of
Decision (ROD) by EPA Region VIII, were 0.55 mg/kg for
heptachlor and 0.15 mg/kg for dieldrin. The analytical
detection limits, 1.6 mg/kg for both contaminants, were not
low enough to determine if these action levels were met [25].
This was due to matrix interferences.
Bench-scale soil-washing tests conducted at the FMC
Fresno Superfund site demonstrated that contaminant re-
duction for any size fraction greater than 200 mesh is most
influenced by the number and types of washes used. A
single wash removed about 77 percent of the dieldrin from
soil, but three washes using a surfactant removed 99 per-
cent [26]. Additional studies at the FMC site were performed
using a froth flotation wash. Data indicate that this surfac-
tant-assisted wash procedure removed an average of 80 to
85 percent of the organochloropesticides (WG02 and WG03)
in one wash cycle; 92 to 99 percent removal was achieved
with a triple wash. Froth flotation washing removed 81 to 85
percent of the organo-phosphorus pesticides with one wash
cycle [26].
High percentages of clay, silt, and humic content may
have a negative effect on contaminant removal and overall
volume reduction. This is because pesticides bind chemi-
cally or. physically more readily to clay and silt particles.
Media with high cation exchange capacity also bind some
organic and organo-metallic pesticides that may be difficult
to separate using this technology [17,27,28].
Process Residuals
Residuals from the aforementioned process units may
include oversize rocks, debris, and coarse material, air
emissions, wastewater, and contaminated sludges or fines.
Oversize fractions are often minimally contaminated and
can be returned as backfill to the site with little or no
treatment. Debris that is porous in nature, such as wood,
roots, and vegetation, may be highly contaminated and
require off-site disposal. Treatment units for pesticide-
laden system wastewater include carbon adsorption, chemi-
cal or photochemical oxidation, or biological oxidation. Con-
taminated fines resulting from the soil washing subsystem
can be treated either on or off site by processes such as
biological or chemical oxidation, incineration or solidifica-
tion/stabilization in conjunction with land disposal
[16,17,18,19,20,21].
Solvent Extraction
Solvent extraction is an innovative technology that uses
organic solvents to extract organic contaminants from soils.
Solvent extraction is mainly applicable to the decontamina-
tion of soils containing volatile and nonvolatile hydrophobia
organics, such as pesticides. This technology achieves
volume reduction by concentrating the pesticides into an
extract phase, from which the contaminants can be recov-
ered, further concentrated or disposed.
There are two broad categories of processes: conven-
tional solvent extraction and supercritical fluid extraction.
Conventional solvent extraction uses organic solvents to
selectively extract the contaminants. This process may
need to be repeated several times to extract the contami-
nant to a certain concentration level. The solvent itself can
be treated and recycled. Supercritical fluid extraction uses
a highly compressed gas (e.g., carbon dioxide) above its
critical temperature to perform the extraction. This highly
compressed gaseous fluid can be especially useful in re-
moving contaminants from interstitial spaces of the ma-
trix[1,30]. Supercritical CO2 extraction is presented in a
separate section. Solvent extraction technology potentially
can be used for treatment of pesticides from waste groups
WG02, WG03, and WG04 [29,30,31].
Process Description
This process achieves volume reduction by concentrat-
ing the pesticide into an extract phase. Solvent extraction
typically consists of three types of subsystems:
• feedstock preparation
• extraction
• residuals treatment/solvent recovery.
As with soil washing, solvent extraction feedstock prepa-
ration typically includes excavation, followed by screening
operations to segregate the soil by size into highly contami-
nated fines and minimally contaminated coarser soil frac-
tions. This initial volume reduction can reduce the amount
of soil that must be extracted, reducing the overall treatment
cost. Some commercially available units treat the entire soil
mass without initial volume reduction. If the soil is very wet
(e.g., >70 percent moisture content), a dewatering unit is
used to remove excess moisture before the extraction pro-
cess [20,27,29,31,32,33].
During the soil extraction process, pesticide-contami-
nated soil is mixed with an appropriate solvent in a tank-
based continuous countercurrent extraction. The extraction
process may require several passes to reduce the solid-
phase pesticide contamination to the desired level. After
extraction, the solvent extract is pumped to a sedimentation
tank for removal of soil fines [20,27,29,31,32].
A suitable solvent should:
have high selectivity for the contaminant(s)
have high saturation solubility for the contaminant(s)
be immiscible in the feed material
be stable
be nonreactive and noninterfering with other soil-matrix
components
• have favorable density, viscosity and interstitial tension
properties
• have a sufficiently different boiling point from the
contaminant(s) to allow post-treatment separation
[29,34,35].
Residuals treatment subsystems include unit opera-
tions for air emission control, decontamination of the extrac-
tion solvent to allow solvent recycle and removal of residual
solvent from the treated soil [20,27,29,31,32,33].
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
Data Needs for Technology
Implementation
Data needs and possible effects for this technology are
presented In Table 11.
Performance
The Sanivan Group developed the Extraksol™ solvent
extraction process which was used to treat PGP-contami-
nated soil for the purpose of system development and
demonstration of capabilities. A proprietary solvent was
used In the 1-ton-per-hour pilot-scale unit. The process
efficiency, presented in Table 12, was greater than 90
percent and greater than 99.7 percent, respectively, in two
tests conducted on contaminated porous gravel. In addi-
tion, low post-treatment POP concentrations were achieved
(<0,82 mg/kg and <0.21 mg/kg). In a test on POP-contami-
nated porous stones, the removal efficiency was lower, at 50
percent [32].
A bench-scale study using the B.E.S.T.™ process mar-
keted by Resource Conservation Company (RCC) demon-
strated a 99 percent removal efficiency for a number of
pesticides !n waste groups WG02 and WG03. Data from this
study is presented in Table 13. Data from other bench-scale
tests using this process indicate chlordane removal efficien-
cies greater than 99 percent [1].
Process Residuals
Residuals include oversize materials, spent solvent,
gaseous solvent emissions and treated soil. Oversize soil
fractions can be returned to the site as backfill if sufficiently
clean. To improve process economics, the solvent extract
is generally recovered and recycled back to the extraction
process. The mode of solvent recovery depends on the
physical and chemical properties of the extract (solvent and
contaminant). For pesticide extraction operations, distilla-
tion or evaporation can be used to recover a volatile solvent
from the less volatile contaminant. I n some cases, a second
extraction with an aqueous solution may be the method of
primary solvent recovery.
The extracted soil may need treatment to remove ex-
cess residual solvent. Dewatering (e.g., centrifugation), air
or steam stripping, vacuum extraction, or biological treat-
ment can be used to remove residual solvent from the soil.
Gaseous emissions from system operations must be treated
before release [20,27,29,31,32,33].
Table 11. Data Needs for Solvent Extraction. [36]
Data Needs
Possible Effects
Complexity of waste mixture
Particle size
PH
Contaminant size
Temperature
Metals
Organically bound metals
Detergents/emulsifiers
Soli permeability
Solvent characteristics
Solvent extraction capacity
Soil moisture content
Affects solvent selection
Oversize particles may require size reduction pretreatment
Must be in a range compatible with extracting solvent
Affects solvent selection and process efficiency; solvent extraction is least
effective for very high molecular weight and very hydrophilic organics
May impact solubility of contaminants in extraction solvent - this affects
extraction efficiency
Strong reaction may occur during treatment process because of caustic
additions
May be extracted along with organic pollutants and cause disposal/recycling
difficulties
May retain organic contaminants and reduce effectiveness of process; may
cause foaming, which hinders settling and separation characteristics
Affects solvent-contaminant contact; low permeability soils may require
additional contact time for effective treatment
May impact treatment process if nonbiodegradable, toxic, or nonvolatile
Affects mass of contaminant that can be solubulized in the solvent
Affects solvent-contaminant contact; soils containing more than 30 percent
moisture may need to be dewatered before treatment
Table 12. PCP Removal Obtained in 1 Ton/Hour Extraksol™ Pilot-Scale Solvent Extraction Unit. [32]
Type of Waste Type of Solvent3
"proprietary
Initial PCP Cone.
(mg/kg)
Final PCP Cone.
(mg/kg)
Removal (%)
porous gravel
porous gravel
porous gravel
#2
#2
#2
8.2
81.4
38.5
<0.82
<0.21
19.5
>90
>99.7
50
70
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
Table 13. Pesticide Removal in Bench-Scale Study Using B.E.S.T.™ Solvent Extraction Process. [37]
Analyte
p,p'-DDT
p,p'-DDE
p,p'-DDD
Endosulfan-l
Endosulfan-ll
Endrin
Dieldrin
Toxaphene
BHC-Beta
BHC-Gamma (Lindane)
Pentachlorophenol
Feedstock (ppm)
500
84
190
250
140
140
37
2,600
<30
<30
150
Product Solids (ppm)
0.2
0.5
0.05
<0.02
<0.02
0.02
<0.02
0.9
<0.13
<0.07
1.9
Removal Efficiency (%
99.96
99.40
99.97
>99.99
>99.99
99.99
>99.95
99.97
98.7
Supercritical CO2 Extraction
Supercritical CO2 (SCO2) extraction is a type of solvent
extraction that exploits some unique properties of
supercritical fluids. Many gases, including CO2, exhibit
enhanced solvent properties when compressed at condi-
tions above their critical temperature (the temperature above
which the gas cannot exist in the liquid state, regardless of
pressure). Supercritical carbon dioxide forms when CO2 is
heated and compressed above 31 °C and 1078 psi. In the
supercritical state, the CO2 is not a liquid, although it exhibits
liquid-like densities and displays much better solubilizing
properties and mass transport characteristics than subcriti-
cal, gaseous CO2. Because the supercritical fluid remains
in the gaseous state, it can penetrate spaces within contami-
nated soil much more readily than liquid solvents [29,30].
Several other gases such as ethylene, ethane, propane and
dichlorodifluoromethanol (Soivent-12) have been tested in
addition to CO2 for treatment applications of supercritical
fluid extractions[29].
Process Description
SCO2 extraction systems consist of an extraction vessel
that can be operated at elevated temperatures and pres-
sure. Carbon dioxide from a liquified bulk supply is piped to
a storage vessel where it is compressed to the desired
operating pressure. The pressurized CO2 is then heated to
the system operating temperature and piped to the extrac-
tion vessel containing the contaminated soil. After the
extraction process, contaminated supercritical CO2 is piped
to a separation vessel, where the pressure is rapidly re-
duced, causing SCO2 to undergo phase transformation to
gaseous subcritical CO2. At lower temperatures and pres-
sure, the dissolved organic contaminants precipitate in the
bottom of the separation vessel. Uncontaminated, gaseous
CO2 is piped to the storage vessel for recycling, while the
extracted organics are collected for disposal [29,30].
Data Needs for Technology
Implementation
Data needs for supercritical CO2 extraction are pre-
sented in Table 14.
Performance
Supercritical fluid extraction processes have been used
extensively in various applications such as decaffeinating
coffee and extracting cholesterol from eggs, drugs from
plants, and nicotine from tobacco [6]. The full-scale appli-
cation of supercritical fluid extraction to the remediation of
contaminated soils is in its infancy. Bench-scale SCO2
studies on pesticide-contaminated soil suggest that full-
scale implementations will be successful [6,38]. A pilot-
scale supercritical fluid system that successfully remediated
PCB-contaminated sediment using a mixture of propane
and butane as the extracting solvent was demonstrated by
CF Systems Corporation under the SITE Program [39].
The efficiency and choice of operating conditions of
SCO2 extraction systems for performing pesticide-contami-
nated site soil remediations will most likely depend on the
specific contaminants present. Several sets of conditions
(e.g., temperature and pressure combinations) may be
needed to extract soils contaminated with more than one
pesticide [6,29,30,38].
Table 14. Data Needs for Supercritical CO. Extraction [6,29,38]
Data Needs
Possible Effects
Complexity of waste mixture
Contaminant polarity
Soil permeability
Affects temperature and pressure combinations required for effective
treatment
Extractive efficiency of polar pesticides may increase with the addition of an
enhancer, such as methanol or acetone
Affects solvent-contaminant contact; low permeability soils may require
additional contact time for effective treatment
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
Process Residuals
Residuals Include treated soils, recyclable CO2 gas,
and liquid- or solid-phase pesticide contaminants. Decon-
taminated soils can be backfilled on site. The recondensed,
separated pesticide contaminants can be stabilized and
disposed of In a RCRA-permitted landfill. The CO2 gas can
be recycled to the extraction process [6,29,30,38].
Comparison of Option Costs,
Advantages and Limitations
Costs
Figure 1 presents the cost ranges for the technologies
discussed in this document; Table 15 lists critical factors
affecting the cost ranges for the technologies discussed.
Other remedial alternatives discussed in the primary refer-
ence document, Contaminants and Remedial Options at
Pesticide Sites, are included for comparison. This informa-
tion should be used as a guide only. Specific cost estimates
should be generated for each site based on specific needs
and circumstances. These costs include capital operations
and maintenance (O&M) costs.
Advantages and Limitations
Tables 16 and 17 present generalized advantages and
limitations, respectively, of the treatment technologies dis-
cussed. Other remedial options discussed in the primary
reference are included for comparison purposes. Limita-
tions specific to a technology or site application are not
addressed.
EPA Contact
Technology-specific questions regarding remedial op-
tions at pesticide sites may be directed to:
Richard N. Koustas
U.S. Environmental Protection Agency
Risk Reduction Engineering Lab
2890 Woodbridge Avenue (MS 106)
Edison, N.J. 08837
Phone: (908) 906-6898
FAX: (908) 906-6990
E-mail: Koustas.Richard@ EPAMAIL.EPA.GOV
Acknowledgements
This bulletin was prepared for the U.S. Environmental
Protection Agency, Office of Research and Development,
National Risk Management Research Laboratory, Edison,
NJ by IT Corporation under Contract No. 68-C2-0108. The
primary reference document, "Contaminants and Remedial
Options at Pesticide Sites" [1], was prepared by Roy F.
Weston, Inc. Mr. Richard Koustas served as the EPA
Technical Project Monitor. This bulletin was authored by
Ms. Ida Bennett, Mr. Gregory McGraw and Ms. Jennifer
Platt of IT Corporation.
Mr. Gregory McGraw served as Task Manager and Mr.
Thomas Janszen of IT Corporation contributed his time and
comments by participating in the review meetings and/or
peer reviewing the document.
Remediation Technologies
Cost($/ton)
100 200 300 400 500 600 700 800 900 1000
Separation/Concentration Options
Radio Frequency Heating
Thermal Desorption
Soil Washing
Solvent Extraction
Containment/Immobilization Options
Stabilization/Solidification
Vitrification (In-Situ)
Destruction Options
Incineration
Ultra High Temperature Process
Chemical Oxidation
DohatogonaltoaHydrodehalogenalion
Hydrolysis/Neutralization
Bloremediation
*No cost estimates for supercritical CO2 extraction are available
blndmirat!on and vitrification costs are per cubic yard
"Cost estimates ware obtained from the references provided and through contact with technology vendors
Rgure 1. Available Estimated Cost Ranges for Pesticide-Contaminated Soil Remediation Technologies"'1"'0. [1,40,41]
12 Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
Table 15. Factors Affecting Cost Ranges for Technology
Alternatives for Remediating Pesticide-Con-
taminated Soil.
technology for which) cost Incurred increased because of this factor
Table 16. Advantages for Technology Alternatives for
Remediating Pesticide-Contaminated Soil.
Advantages
Proven ability to reduce high concentrations to
clean-up goals
Destroys or detoxifies pesticides
Can be Implemented in-silu
Concentrates pesticides, reducing disposal costs
Effective on some Inorganic co-contaminants
0 technology for which a specific advantage Is applicable
Table 17. Limitations for Technology Alternatives for
Remediating Pesticide-Contaminated Soil.
High moisture content adversely affects treatment
Pesticides must be destroyed by another process
Produces residuals/off gases requiring treatment
and/or disposal
Sensitive to median particle size, pH and/or media
characteristics
Sensitive to co-contaminants
aaaaaaanaaaaa
• technology for which a specific limitation Is applicable
REFERENCES
1. USEPA. 1994. Contaminants and Remedial Options at
Pesticide Sites. EPA Contract No. 68-03-3482. Risk
Reduction Engineering Laboratory, Washington D.C.,
Office of Research and Development, Cincinnati, OH,
EPA 540/R-94/202.
2. Federal Insecticide, Fungicide, and Rodenticide Act,
Public Law 92-516.
3. USEPA. 1988. Pesticides in Ground Water Data
Base: 1988 Interim Report. Environmental Fate &
Ground Water Branch, Environmental Fate & Effects
Division, Office of Pesticide Programs, EPA 540-09-89-
036.
4. USEPA. 1991. FATE: The Environmental Fate Con-
stants Information System Database. Environmental
Research Laboratory, Office of Research and Develop-
ment, Athens, GA.
5. USEPA. 1990. National Survey of Pesticides in Drink-
ing Water Wells. EPA 570-9-90-015.
6. Hunter, G.B. January 1992. Extraction of Pesticides
from Contaminated Soils Using Supercritical Carbon
Dioxide. In Proceedings of International Workshop on
Research in Pesticide Treatment/Disposal/Waste Mini-
mization, T.D. Ferguson, Editor. EPA/600/9-91/047.
7. Dev, Harsh and Tom Bajzek. Hydrocarbon Removal by
In Situ Heating of Soil by Electrical Energy. ITT Re-
search Institute, Chicago, IL.
8. Dev, Harsh, Guggilam Sresty, and Paul Carpenter. In
Situ Soil Decontamination by Radio Frequency Heating.
ITT Research Institute, Tyndall Air Force Base, FL.
9. U.S. Army. November 1992. Rocky Mountain Arsenal
In Situ Radio Frequency Heating/Vapor Extraction Pilot
Test Report, Volume I. Document Control No. 5300-01-
12-AAFP. Rocky Mountain Arsenal, Commerce City,
CO.
10. USEPA. 1991. Engineering Bulletin: Thermal Desorp-
tion Treatment. EPA-540-2-91-008. Office of Emer-
gency and Remedial Response, Washington D.C.,
Office of Research and Development, Cincinnati, OH.
11. USEPA. July 1995. Applications Analysis Report: Low
Temperature Thermal Aeration (LTTA) Process,
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
13
-------
Canonla Environmental Services, Inc. EPA/540/AR-93/
504. Office of Emergency and Remedial Response,
Washington, D.C., Office of Research and Develop-
ment, Washington, D.C.
12. Roy F. Weston, IncVREAC and Foster Wheeler
Enviresponse, Inc. 1993. EPA Contract No. 68-03-
3482 and 68-C9-0033. Contaminants and Remedial
Options at Solvent-Contaminated Sites. Roy F. Weston,
Inc., REAC, Edision, NJ.
13. USEPA. 1989. Guide for Conducting Treatability Stud-
ies under CERCLA: Interim Final. EPA-540-2-89-058.
Office of Emergency and Remedial Response, Wash-
ington D.C., Office of Research and Development, Cin-
cinnati, OH.
14. USEPA. 1994. Technology Applications Report: Low
Temperature Thermal Aeration (LTTA) Process,
Canonie Environmental Services, Inc. EPA/540/A5-93/
504. Office of Emergency and Remedial Response,
Washington, D.C., Office of Research and Develop-
ment, Cincinnati, OH.
15. T H Agriculture & Nutrition Company, Inc. 1992. Use of
Thermal Desorption for Treatment Pesticide Contami-
nated Soils. Report submitted to U.S. Environmental
Protection Agency, Region IV, Atlanta, GA.
16. Dennis, R.M., D. Dworkin, and W.L. Lowe. 1991.
Evaluation of Commercially Available Soil Washing Pro-
cesses for Site Remediation. Proceedings from Hazard-
ous Material ControI/Superfund 1991, pp. 333-343.
17. Goldberg, E. 1995. German Washing Process Pulls Out
Contaminants in a Rne Slurry. Soil and Groundwater
Cleanup, August/September, pp. 34-37.
18. Sachse, J.D., AJ. Dietrich, D.H. Weigle, C.P. Keegan,
D.C. Grant, and E.J. Lahoda. 1994. Mobile Soil Wash-
Ing System. Atomwirtschaft Atomtechnik, Vol. 39, No.
3, pp. 199-201.
19. Bieber, D. and K. Crabtree. 1994. Washing Unit
Chums through Diesel. Soils, November, pp. 14-17.
20. USEPA. June 1993. Applications Analysis Report: Re-
sources Conservation Company B.E.S.T.™ Solvent Ex-
traction Technology. EPA/540/AR-92/079. Office of
Solid Waste and Emergency Response, Washington,
D.C., Office of Research and Development, Cincinnati,
OH.
21. USEPA. 1990. Engineering Bulletin: Soil Washing
Treatment. EPA-540-2-90-017. Office of Emergency
and Remedial Response, Washington, D.C., Office of
Research and Development, Cincinnati, OH.
22. USEPA. 1988. Technology Screening Guide for Treat-
ment of CERCLA Soils and Sludges. EPA-540-2-88-
004. Office of Solid Waste and Emergency Response,
Washington D.C.
23. USEPA. September 1994. Innovative Treatment Tech-
nologies: Annual Status Report, Sixth Edition. EPA
542-R-94-0005. Office of Solid Waste and Emergency
Response, Washington, D.C.
24. URS Consultants, Inc., and Hazra Environmental Ser-
vices, Inc. 1992. Pilot-Scale Soil Washing Study, Sand
Creek Superfund Site, Commerce City, CO. Report to
EPA Regions VI, VII, and VIII.
25. Frederick, R.M. and S. Krishnamurthy. 1994. Soil
Washing Treatability Tests for Pesticide-Contaminated
Soil. Remediation/Autumn, Vol. 4, No. 4, pp. 443-453.
26. Bechtel Environmental, Inc. 1990. "Feasibility Study for
the FMC Fresno Plant Superfund Site." Report to MC
Corp., San Francisco, CA.
27. USEPA. November 1989. Innovative Technology:
BEST™ Solvent Extraction Process. Publication No.
9200.5-253FS. Office of Solid Waste and Emergency
Response, Washington, D.C.
28. Conklin, A. 1995. Secrets of Clay: Why is it the Most
Stubborn and Difficult Soil Type to Treat? Soil and
Groundwater Cleanup, August/September, pp. 38-41.
29. Berkowitz, J.B. 1989. Solvent Extraction. In Standard
Handbook of Hazardous Waste Treatment and Dis-
posal, H.M. Freeman, editor, McGraw-Hill Book Com-
pany, NY, pp. 6.77-6.90.
30. DOE. August 1993. Technical Area Status Report for
Chemical/Physical Treatment, Vol. II: Supercritical Fluid
Extraction. DOE/MWIP-8. U.S. Department of Energy,
Office of Technology Development, Washington, D.C.,
pp. L-2.1-2.7.
31. DOE. August 1993. Technical Area Status Report for
Chemical/Physical Treatment, Vol. II: Conventional Sol-
vent Extraction. DOE/MWIP-8. U.S. Department of En-
ergy, Office of Technology Development, Washington,
D.C., pp. L-1.1-1.8.
32. Paquin, J. and D. Mourato. 1989. Soil Decontamination
with Extraksol™. Paper presented at the 3rd Interna-
tional Conference on New Frontiers for Hazardous
Waste Management, Pittsburgh, PA, October 10-13.
33. USEPA. February 1995. SITE Technology Capsule:
Terra-KLeen Solvent Extraction Technology. EPA540/
R-94/521a. Office of Emergency and Remedial Re-
sponse, Washington, D.C., Office of Research and De-
velopment, Cincinnati, OH.
34. USEPA. January 1990. Project Summary: Cleaning
Excavated Soil Using Extraction Agents: A State-of-the-
Art Review. EPA/600/52-89/034. Office of Emergency
and Remedial Response, Washington, D.C., Office of
Research and Development, Cincinnati, OH.
35. Khodacloust, A., P., J.A. Wagner, M.T. Suidan, and
S.I. Safferman. Solvent Washing of PCP Contami-
nated Soils with Anaerobic Treatment of Wash Flu-
ids. Water Environment Research, Vol. 66, No. 5,
pp.692-697.
36. USEPA. 1990. Engineering Bulletin: Solvent Extrac-
tion Treatment. EPA-540-2-90-013. Office of Emer-
gency and Remedial Response, Washington, D.C.,
Office of Research and Development, Cincinnati, OH.
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
37. D.A. Austin. 1988. The B.E.S.T. Process - An Innova-
tive and Demonstrated Process for Treating Hazardous
Sludges and Contaminated Soils. Presented at 81st
Annual Meeting of APCA, preprint 88-68.7, Dallas, TX.
38. Dooley, K.M., R. Gambrell, and F.C. Knopf. 1988.
Supercritical Fluid Extraction and Catalytic Oxidation of
Toxic Organics from Soils. In Proceedings of the Thir-
teenth Annual Research Symposium, Office of Re-
search and Development, Cincinnati, OH.
39. USEPA. August 1990. Applications Analysis Re-
port: CF Systems Organic Extraction Process, New
Bedford Harbor, MA. EPA/540/A5-90/002. Office of
Emergency and Remedial Response, Washington,
D.C., Office of Research and Development, Cincin-
nati, OH.
40. USEPA. January 1993. Selected Alternative and Inno-
vative Treatment Technologies for Corrective Action and
Site Remediation. EPA/542/B-93/001.
41. USEPA. September 1994. Innovative Treatment Tech-
nologies: Annual Status Report, Sixth Edition. Office of
Solid Waste and Emergency Response. EPA 542-R-
94-005.
Engineering Bulletin: Separation/Concentration Technology Alternatives for the Remediation of Pesticide-Contaminated Soil
-------
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Please make all necessary changes on the below label,
detach or copy, and return to the address in the upper
left-hand corner.
If you do not wish to receive these reports CHECK HERE [3;
detach, or copy this cover, and return to the address in the
upper left-hand comer.-
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use
$300
EPA/540/S-97/503
------- |