SWR# 803
EPA 600/D-84-00tf
PROMISING SITE CLEANUP TECHNOLOGY	PB84-129386
by
Ronald D. Hill
U. S. Environmental Protection Agency
Municipal Environmental Research Laboratory
Solid and Hazardous Waste Research Division
26 West St. Clair Street
Cincinnati, Ohio 45268
INTRODUCTION
Within the EPA Office of Research and Development, the Solid and
Hazardous Waste Research Division (SHWRD), Municipal Environmental
Research Laboratory, has the responsibility for the control development
program in support of "Superfund." The SHWRD research and development
program has been organized to correspond with the "Superfund" legisla-
tion, i.e. the Oil and Hazardous Materials Spills Branch deals with
removal actions (emergency), and the Disposal Branch deals with remedial
actions. Due to the special demands of "Superfund," the normal research
and development process of concept development, laboratory evaluation,
pilot testing, and field demonstration cannot be followed. "Superfund"
is a 5-year program requiring answers today. Thus, our program is one
of technology assessment to determine cost and effectiveness, adaptation
of technologies to the uncontrolled waste site problem, field evaluation
of technologies that show promise, development of guidance material for
the EPA Office of Emergency and Remedial Response (OERR), technical
assistance to OERR, and EPA Regional Offices. A brief overview may
clarify our program goals.
Removal (Emergency) Actions
This program can be divided into three major areas of activity:
(1) Personnel Health and Safety, (2) Demonstration of Equipment, and (3)
Chemical Countermeasures. The goal of the personnel health and safety -
program is to develop protective equipment and procedures for personnel
working on land or underwater in environments which are known or suspected
to be immediately dangerous to life or health, so that such personnel
can conduct operations related to investigating, monitoring, or cleaning
up of hazardous substances. In addition, it is hoped that this equipment
and procedures will result in greater worker efficiency and lower opera-
tional cost, as well as improvement of personnel safety.
Our major effort on removal technology centers on demonstration of
equipment designed for hazardous spill control. This equipment is being
modified, adapted, and field tested. Examples, which I will discuss in
more detail later, include a mobile incinerator, carbon regenerator, and
soils washer.
Presented at Conference entitled "Superfund Update: Cleanup Lessons Learned,"
October 11-12, 1983, Schaumburg, Illinois.
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The chemical countermeasures program is concerned with the use of
chemicals and other additives that are intentionally introduced into the
open environment for the purpose of controlling the hazardous contami-
nants held within, e.g. soil or surface and groundwater. However, the
use of such agents poses a distinct possibility that the release situa-
tion could be made worse by the application of an additional chemical or
other additive. Therefore, the objective of this activity is to define
technical criteria for the use of chemicals and other additives at
release situations of hazardous substances such that the combination of
released substances plus the chemical or other additives, including any
resulting reaction or change, results in the least overall harm to human
health and to the environment. I will further explain this program
later.
Remedial Actions
We have divided the remedial action program into three major areas
of activity: (1) Survey and Assessment of Current Technologies, (2)
Field Demonstration and Verification of Techniques, and (3) Site Design
Analysis.
We feel there is much to be learned from the remedial actions that
have already been conducted by federal and state governments and industry.
Thus, we have an ongoing and continuing effort to review and evaluate
techniques that are being used and have been used in the past at uncon-
trolled hazardous waste sites. Our analysis includes defining the site-
specific problem, determining the problems associated with implementing
the technique, determining the effectiveness, and identifying the cost.
We have found the data base on many of the early remedial actions to be
inadequate for a good evaluation; however, those actions taken in the
last few years are providing much better information. The survey results
and the data used in our technical handbooks will be published on a
regular basis. We hope to computerize this data base in the future.
Techniques that have a potential for being cost-effective are being
field verified. These field evaluations are conducted in two ways. We
will actually field test a technique that looks very promising or we
will conduct an intensive field evaluation of a technique being installed
as part of a remedial action. In practice, our research program provides
the additional resources needed to obtain an array of operational monitor-
ing data which will be adequate to fully evaluate and assess a technique.
An example of a field test conducted by us is the "Block Displacement"
isolation method which I will discuss later. An evaluation of a slurry
trench installed at a "Superfund" site in New Hampshire is an example of
a field evaluation.
Our third area is an outgrowth of the first two, that is, the
development of technical handbooks to be utilized by the planners and
designers of remedial actions. Below is a listing of the handbooks that
have been prepared or are in progress:
o Remedial Action at Waste Disposal Sites - 6/82
o Reviewers of Proposed Hazardous Waste Remedial Actions - 9/83

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o Cover Design and Installation - 11/84
o Fixation/Solidification of Waste in Surface Impoundments - 11/84
o Decontamination of Buildings, Structures, and Construction Sites -
5/85
o Slurry Trench Design and Installation - 3/84
o Procedures and Techniques for Controlling the Migration of Leachate
Plumes - 3/84
Superfund Problem Areas
To facilitate this presentation, I would like to divide the "Superfund"
program into four problem areas. This list 1s not intended to be all
encompassing, but 1t will be used to focus n\y discussion on "promising
site cleanup technology."
Problem areas
o Drums/containers filled with hazardous waste
o SoUs/sludges/sediments
o Ultimate destruction
o Groundwater
Following are several descriptive summaries of research projects
which we have recently completed or have currently underway in these
areas.
Drums/Containers
We have all seen pictures of hazardous waste sites with piles of
deteriorating drums oozing hazardous waste. SHWRD supported a project
that reviewed the current state-of-the-art on handling drums at uncontrolled
sites and recommended areas of future research needs. This report is
being combined with an OERR drum-handling effort into a drum-handling
handbook that should be available in June 1984. In general, the study
found that the current procedures and drum-handling equipment are adequate.
SHWRD has been pursuing a new technique for drum encapsulation that
shows promise. The following is a description of that activity.
Polymeric Overpack for 55-Gallon Drums
A prototype full-scale process and equipment have been developed
and evaluated for encapsulating corroding 55-gallon drums of hazardous
waste. The overpack system will provide a means for reducing the health
and safety hazards associated with containing and transporting leaking
55-gallon drums and other containers or waste forms from an uncontrolled
site to a final disposal site.
The overpack process utilizes friction-welding (spin-welding) to
fuse a polyethylene (PE) cover onto a PE receiver into which a 55-gallon
drum of waste has been inserted. Friction welding involves rotating one
piece of plastic in contact with another stationary plastic piece. In
the case of the overpack process, the cover is rotated while the receiver
containing the waste is clamped in a stationary position. Friction

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causes the contact surfaces of both pieces to melt. Rotation is stopped
and the pieces are pressed together. The melted polyethylene solidifies
and the two pieces are fused together, creating a seal. The overpacks
are fabricated by rotomolding a 1/4-inch thick container from PE and
sectioning the container into a receiver and cover.
The thickness of the overpack is controlled by varying the amount
of powdered PE placed into the rotomolder. The top (cover) is designed
with ribs to accommodate the spin-welding tool. The overpack 1s approxi-
mately 85 gallons in size and large enough to accept drums that may be
partially deformed. The friction welding machine consists of a
hydraulically-operated plate used to spin the PE cover. Other features
include the appropriate hydraulics, valves, controls, switches, a platform,
and features necessary to position and seal the cover to the container.
One operator is required to man the machine during the welding operation.
The equipment is designed to be easily transported from site to site.
Appropriate fork lifts and other drum-handling equipment are required at
facilities handling the drums and the overpack system. Overpacks are
designed for easy stacking and can be handled with conventional drum-
handling equipment.
Rotomolded PE overpacks have been successfully sealed using the
friction-welding equipment. Sealed overpacks have been subjected to
hydrostatic burst tests and have exceeded the performance of similar
size metal drums. Specimens under tensile testing of the weld have
failed at points other than the weld. Leach testing of the welded
overpacks has shown that the containers are leak tight. Details of the
test results, including micrographic examination of the seals and crush
testing, are available.
Additional expected performance data can be extrapolated from
previous studies and from the fact that PEs and other plastics are well
characterized. They provide a unique combination of excellent chemical
stability, flexibility, and mechanical toughness. Expected mechanical
performance of the overpack system can be increased by filling the void
between the drum and the PE overpack. This can be done with sands,
soil, absorbant, off-spec Portland cement, or other inert material.
The value of the friction-welded seal is in its capability to
remain leak-tight under stresses that will normally force conventional
screw caps, clamps, and similar seals to break or open.
An evaluation of the overpack process is being planned to prove the
equipment performance and the ability to produce a leak-tight seal.
Approximately 85-100 drums of waste will be overpacked. Random samples
will be subjected to testing to further evaluate the performance of the
overpack system. Because of the requirement to process 85-100 drums,
the equipment as designed and constructed is essentially full-scale.
However, the evaluation will also point to design modifications that
will improve the performance. One example is the operation of multiple
spin-welding plates from a single unit. This would increase processing
capabilities.

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b
Data from the evaluation and previous encapsulation studies will
provide sufficient information to make the plastic overpack process
available for use in several ways. It was specifically conceived as a
superior overpack to decrease the health and safety hazards associated
with the containment, transportation, and disposal of leaking drums from
uncontrolled sites. However, it has potential application as an accept-
able long-term containment system for the disposal of hazardous waste
from small quantity generators. Additionally, because of its superior
seal, the system could be used for the safe, long-term storage of hazardous
waste that might be recovered in the future.
Soi1s/Sludges/Sediments
Soils, as well as sludges and sediments contaminated with hazardous
materials, have been one of the most complex and perplexing problems to
face the cleanup practitioner. For example, 500,000 cubic yards of soil
contaminated with dioxin are reported to be located in Missouri. In the
case of dioxin-contaminated soil, a concentration as low as one part per
billion is of concern. At almost all hazardous waste sites some soil
pollution has occurred due to the storage and processing of waste, or as
leakage from tanks, drums, and lagoons. Landfills and capping have been
the most popular control technology used, however, these techniques do
not always give the assurance of complete and final control that the
public desires. Many innovative concepts have been proposed to treat
contaminated soils, sludges, and sediments, including:
o Inplace leaching
o Inplace biological degradation of hazardous components, including
the use of "Superbugs"
o Inplace chemical treatment
o Removal/treatment, e.g. Gairena Radiation, ultraviolet, chemical
treatment, and wet air oxidation
o Land treatment or composting
o Soil washing (solvent extraction)
o Thermal treatment, e.g. incineration, molten salt, and microwave
plasma
0	Fixation, e.g. organic polymers
1	would like to discuss a few of the promising techniques that
SHWRD is pursuing.
Mobile Soils Washing System
SHWRD has developed a Mobile Soils Washing System that can be used
to treat excavated soils at sites where in-situ washing is ineffective
or not applicable, and where hauling of excavated soil to a landfill is
not cost-effective or is undesirable because of environmental or insti-
tutional barriers.
The system is capable of extracting contaminants from soils—"arti-
ficially leaching" the soil using a water-based cleaning agent--and
thereby enabling operators to leave the treated soil on-site. To accomplish
this, the soil is passed through a rotating drum screen water knife soil
scrubber where soil lumps are broken apart by intense jets of water, and

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chemicals are tripped from soil particles. The resulting soil slurry 1s
fed into a four-stage countercurrent chemical extractor. Each stage
consists of a mixing, froth-flotation cell connected in series with
hydrocyclones which centrifugally separate solids from liquids. The
soil particles are agitated repeatedly in washing fluid and are pro-
gressively decontaminated as they flow through each stage. The cleansed
soil is then returned to the site. The extracted hazardous contaminants
are separated from the washing fluid using physical/chemical treatment
procedures (flocculation, sedimentation, carbon adsorption, etc.). The
cleaned washing fluid is recirculated while the separated and concentrated
contaminants are disposed of by appropriate means.
3
The Soils Washing System is capable of processing 4 to 18-yd of
contaminated soil per hour, depending on the soil particle size and the
nature of the contaminant.
Current activity includes the shakedown of the system and complete
full-scale, controlled-condition tests using water-based wash fluids to
ensure that the system operates properly and performs within a delineated
range of soil and pollutant parameters. Plans also call for an investi-
gation of the feasibility of using the Soils Washing System with organic
solvents to extract dioxin from wet excavated soils.
Chemical Countermeasures
One key countermeasure is the use of chemicals and other additives
that are intentionally introduced into the open environment for the
purpose of controlling the hazardous contaminant. The use of such
agents, however, poses a distinct possibility that the release situation
could be made worse by the application of an additional chemical or
other additive. Therefore, the objective of this R&D activity is to
define technical criteria for the use of chemicals and other additives
at release situations of hazardous substances such that the combination
of released substance plus the chemical or other additive, including any
resulting reaction or change, results in the least overall harm to human
health and to the environment.
The Chemical Countermeasures Program (CCP) has been designed to
evaluate the efficacy of in-situ treatment of large volumes of subsurface
soils, and large, relatively quiescent waterbodies. For each situation,
the following activities are planned: (a) a literature search to develop
the body of existing theory and data; (b) laboratory studies on candidate
chemicals at small scale to assess adherence to theory and define likely
candidates for full-scale testing; (c) full-scale, controlled-condition,
reproducible tests to assess field operation possibilities; and (d)
full-scale tests at a site-of-opportunity. After the data are developed
for a given chemical use situation, a technical handbook will be prepared.
To date, efforts have concentrated on soils-related activities and
have taken this aspect of the program through the laboratory studies to
a point where a decision will be made on continuation into full-scale
controlled-condition testing. The laboratory studies were used to
determine whether significant enhancements to the in-situ cleanup of
chemically contaminated soils with standard water washing techniques

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could be obtained by using aqueous surfactants. The addition of the
surfactant mixtures was designed to improve the solvent properties of
the water and enhance the removal of adsorbed chemical contaminants.
Based on the results of the literature search, three pollutant
groups (mixtures of compounds) were selected for laboratory testing
on soils:
1.	High molecular weight polynuclear aromatic and aliphatic
hydrocarbons (distillation fraction of Murban crude oil)
D
2.	PCB mixture 1n chlorobenzenes (Aroclor 1260 transformer oil)
3.	D1-, tri-, and pentachlorophenols
Shaker table agitation studies were performed to determine the
maximum cleanup efficiency under equilibrium conditions using water
washes and a combination of 2 percent each of Hyonic PE90 (now known as
NP90 by the manufacturer), and Adsee 799 (Witco Chemical) surfactants.
After the most efficient surfactant concentrations were determined,
column studies were initiated to evaluate soil cleanup efficiency under
gravity flow conditions. In general, overall soil cleanup approaching
the 90 plus percent level was attained with the intermediate molecular
weight aliphatic and aromatic hydrocarbons, the PCB mixtures, and the
chlorinated phenol mixtures. Results appear to support additional
larger scale studies and plans are being discussed to construct a soils
test facility at EPA's OHMSETT facility in New Jersey.
Pending the availability of supplemental FY'84 funds and a positive
decision on construction of the soils test facility, SHWRD would like to
expand the controlled condition testing program to include the investi-
gation of surfactants and other chemicals for decontamination of dioxin-
laden soils.
Asphalt Encapsulation
Asphalt encapsulation techniques, consisting of mixing heated
asphalt with a sludge material, are being considered as a treatment
option (Figure 1). Coating (or microencapsulation) of the sludge
particles would improve the leachate quality and could act to reduce the
hazardous nature of some compounds in the sludge. Additional heating of
the mixture could act to thermally degrade the compound, e.g. nitroaromatic
and ROX compounds.
Research to date has included (1) an evaluation of existing asphalt
encapsulation techniques for hazardous wastes, (2) an evaluation of
alternative heating/mixing systems, (3) review of the properties of
various asphalt products which may be used, (4) laboratory experiments
on the temperature and holding times required for thermal breakdown of
the various compounds present in certain sludges, and (5) preliminary
design of a pilot mixer/heating system. Our first studies have been
with a sludge containing trinitrotoluene (TNT), hexahydro-1,3-5-trinitro-
1,3,5-triazine (RDX), and other nitroaromatics. A synthetic sludge with

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PONO
CLASSIFIER
OPTION
PRETREATMENT
ASPHALT
FEEDER
OPTION
MUCK
FEEDER
BLENDER/
MIXER
OPTION 	
EVAPORATOR/
- HEATER
Lw m—mmm mmmmmm mm
I STORAGE
1 PIT/POND |

I



0ISCMARGE
TO CONTAINERS
Figure 1. Sludge Encapsulation Process

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physical properties similar to the actual sludge will be used during the
initial runs and during modifications of the pilot system. Actual
lagoon sludge will be used in the field for the final testing.
Factors which are being evaluated include residence times required
for both mixing and thermal breakdown, mobility of the hazardous system,
safety considerations, batch feed vs. continuous feed designs, and
through-put rates.
A preliminary study has been completed on the selection of an
asphalt/sludge mixer. The two most promising mixers are the pug mill
and static pipe. Final tests are being made to select a mixer for pilot
studies.
A laboratory evaluation was conducted to assess the temperature and
holding times required for breakdown of the nitroaromatics and RDX in
sludge. This information is necessary to design the mixer system and to
determine if thermal degradation occurs at temperatures below the
flashpoint of available asphalts. A total of 17 heating tests were
conducted, representing four temperatures (150, 200, 250, and 300°C)
and four residence times (5, 10, 15, and 20 minutes) plus one sample
heated for 2 hours at 100°C. The f-esults, however, do indicate that
thermal degradation of approximately 90 percent of the explosive and
nitroaromatic compounds occurs at 250°C. The results are based solely
on the heating of the sludge. Further testing will be required in order
to determine whether various types of asphalt in combination with the
sludge result in equally low levels of explosive and nitroaromatic
compounds. These tests are underway. In addition, studies will be
conducted on utilizing the asphalt encapsulation technique on other
organic waste. Following these tests, pilot-scale evaluation will be
conducted.
Ultimate Destruction
The preferred approach to uncontrolled hazardous waste sites is
conversion of the hazardous material to a nonhazardous form. Several
techniques have been mentioned earlier and include: thermal treatment,
garrnia radiation and ultraviolet treatment, chemical treatment, and bio-
logical treatment. Whereas, some of these techniques are state-of-the-
art for some waste, others are in the research, development, and field
evaluation stage.
Thermal treatment is being extensively studied by EPA. The In-
dustrial Environmental Research Laboratory (IERL) has a comprehensive
program evaluating fixed incineration systems and the utilization of
cement kilns and industrial boilers to burn organic hazardous waste. In
addition, they are evaluating high-technology processes such as wet air
oxidation, molten salt, and microwave plasma. SHWRD has concentrated
its efforts on mobile incineration units that can be taken directly to
the uncontrolled sites. Two types of units are under study—mobile and
modular.

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Mo btT"e~Inctnerat1^h~Sys"t em	
SHWRD has developed a mobile incineration "system designed for field
use to destroy hazardous organic substances collected from cleanup
operations at spills or at uncontrolled hazardous waste sites. EPA
develops such equipment to actively encourage the use of cost-effective,
advanced technologies during cleanup operations.
The mobile incineration system is designed to meet the requirements
of TSCA and RCRA and provide state-of-the-art thermal detoxification of
long-lived, refractory organic compounds, as well as debris from cleanup
operations. Hazardous and toxic substances that could be incinerated
include compounds containing chlorine and phosphorus—for example,
PCB's, kepone, dioxins, and organophosphate pesticides, which may be in
pure form, in liquids, in sludges, or in soils.
The mobile incinerator consists of four trailers with specialized
equipment. (See attached Fact Sheet.) In the kiln, organic wastes are
fully vaporized and completely or partially oxidized at 1800°F. In-
combustible ash is discharged directly from the kiln, while off-gases
are passed through the secondary combustion chamber (SCC) at 2200°F.
Here, the thermal decomposition of the contaminants is completed. The
flue gas exits from the SCC and is then cooled from 2200°F to approxi-
mately 190°F in a water spray quench elbow. Excess water is collected
in the quench elbow sump, and the cooled gases then pass to the third
trailer. Here, submicron particulates are removed from the gas stream
as it passes through the cleanable high-efficiency air filter (CHEAF),
and acid gases are neutralized in the mass transfer (MX) scrubber.
Gases are drawn through the entire incineration system by an induced
draft (ID) fan and are discharged from the stack. A monitoring system
is used to analyze the flue and stack gases for combustion components
(carbon monoxide (CO), carbon dioxide (C02), and oxygen (02)), and
emission components (oxides of nitrogen (NO ), sulfur dioxide (S02), and
total hydrocarbons (THC)) to ensure regulatSry compliance and high
thermal combustion efficiency.
To date the operational and performance aspects of the mobile
incineration system have been evaluated during 37 days of shakedown and
TSCA/RCRA compliance trial burn. The performance of the system has been
exceptional in terms of destruction and removal efficiency (DRE) of test
organics and the ability to meet air emission requirements. The DRE for
test compounds, di-, tri-, and tetrachlorobenzenes, carbon tetrachloride,
and PCB's ranged from 99.9991 percent to 99.9999 percent for all test
runs (RCRA requirements, >99.99 percent). The combustion efficiency
(C02/(C02 + CO)) x 100 exceeded 99.999 percent for all tests (TSCA
requirements, >99.9 percent). The removal of HC1 produced from the
combustion of chlorinated test compounds exceeded 99.88 percent (RCRA
requirements, >99 percent). The emission rate of particulate matter was
less than 80 mg/dscm, (RCRA requirements, <180 mg/dscm).
Now that the construction and initial testing of the mobile incin-
erator has been completed, it will be tested under field conditions.
The EPA is currently considering various sites as candidates for the
demonstration tests. These sites include: (1) Times Beach, Missouri,

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&EPA
FACT SHEET
United Slates
Environmental Protection
Agency
April 1982
EPA's Mobile Incineration System for Cleanup of Hazardous Substance Spills and Waste Sites
EPA's Office of Research and Development has recently completed
construction of a mobile incineration system designed for field use to
destroy hazardous organic substances collected from cleanup operations
ai spills or at uncontrolled hazardous waste sites. EPA develops such
equipment to actively encourage the use of cost-effective, advanced
technologies during cleanup operations. Other systems, including two
devices for treating contaminated soils, both after excavation and in-sltu,
are currently under development Once an item of hardware is complete, it
is tested under field conditions After testing, plans, specifications, and
other information are made available publicly for the purpose of
encouraging commercialization of the new technology Numerous systems.
Including a mobile water treatment unit and a mobile laboratory, have been
completed and are now available commercially
The mobile incineration system is designed to EPA's PCQ destruction
specifications to provide state-of-the-art thermal detoxification of long-
lived, refractory organic compounds, as well as debris from cleanup
operations Hazardous substances that could be incinerated include
compounds containing chlorine and phosphorus -• for example, PCB's,
kepone, dioxins, and organophosphate pesticides, which may be in pure
foim, in sludges, or in soils
The mobile incinerator consists of four trailers with specialized equip-
ment (see illustration) In the kiln, organic wastes are fully vaporized and
completely or partially oxidized at 1800°F Incombustible ash is discharged
directly from the kiln, while off-gases are pased through the secondary
combustion chamber (SCC) at 2200°F Here, the thermal decomposition of
the contaminants is completed The flue gas exits from the SCC and is then
cooled from 2200°F to approximately 190aF in the quench elbow. Excess
water Is collected In the quench elbow sump. The gases then pass into the
third trailer Here, submicron particulates are removed from the gas stream
as It passes through Ihe cleanable high-efficiency air filter (CHEAF), acid
gases are neutralized in the mass transfer (MX) scrubber Gases are drawn
through the system by an Induced draft (ID) fan and are discharged from the
stack The monitoring system is used to analyze the flue and stack gases
for combustion components [carbon monoxide (CO), carbon dioxide (COJ,
and oxygen (0,)], and emission components (oxides of nitrogen (NOx). sulfur
dioxide (SO,), and total hydrocarbons (THC))
A 15 hour test burn with fuel oil has been completed, and the system has
undergone priority modifications Identified during this burn. The system is
currently undergoing the final stages of preparation for a "PCB Trial Burn "
The "PCB Trial Burn," scheduled during the summer of 1982, represents a
systematic approach to evaluate and demonstrate the incinerator's ability
to meet and exceed the performance requirements established by Federal.
State, and municipal regulations. After the trials, the system will be
demonstrated at several hazardous wasle sites around the country.
To date (Spring 1982), EPA, through the Oil and Hazardous Materials
Spills Branch at Edison, New Jersey, has spent $2 2 million on the design,
development, testing, and permitting of the mobile incinerator. Fabrication
costs of a similar mobile incineration system (without development and
testing expenditures) Is estimated vo be $1.1 million.
For further Information, contact Mr. Frank Freestone, Dr. John Brugger,
or Mr. James J Yezzl, Jr. Municipal Environmental Research Laboratory,
Oil and Hazardous Materials Spills Branch, Edison, New Jersey Telephone
numbers are: (201) 321-6632 (commercial) or 340-6632 (FTS).
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to demonstrate the detoxification of d1ox1n-contam1nated soil by thermal
incineration; (2) K1n-Buc landfill 1n Edison, New Jersey, to destroy 300
barrels of PCB-contamlnated oily leachate; and (3) Hyde Park, New York,
to demonstrate the thermal destruction of dloxin-containlng sludges at a
landfill site. After testing, the plans, specifications, and other
information will be made available publicly for the purpose of encourag-
ing conmercialization of the new technology.
Modular Transportable Incineration System
An initial study has been proposed to determine the utilization of
a modular transportable incineration system. The purpose of the study
is to examine the technical, administrative, and economic feasibility of
the use of modular incineration systems for destruction of toxic organic
wastes at Superfund sites in the United States. Such wastes may include
materials such as dioxins, organophosphate and carbamate pesticides,
PCB's, and other organic substances recognized as highly toxic. The
modular system would have a capacity 5-10 times the existing EPA Mobile
Incineration System, and would be assembled from commercially available
components (taking maximum advantage of existing equipment and tech-
nology) at a site selected to be within an economic transport radius of
several sites needing cleanup. At the conclusion of cleanup operations,
the system would be disassembled and moved to another location, thus
avoiding public reaction to a permanent hazardous waste disposal facility.
This soon-to-be-started feasibility study will address the following
major areas:
System duty requirements, including examination of location and
types of sites having incinerable wastes, and the characteristics
of those wastes;
Capabilities of existing transportable incineration systems, both
domestic and foreign, specifically including systems currently
being developed or operating in the Netherlands and Sweden. The
potential for modification of domestic cement and lime kilns for
use as incinerators is also to be evaluated;
Effects of institutional requirements, such as RCRA and state
permitting restrictions and examination of options for ownership
(government vs. private sector);
Process specifications, including examination of requirements for
incinerating liquids and solids based upon the potential quantity
of each;
Cost analysis, including an examination of the effects of process
selection, mode of transport (rail, barge, highway), capacity,
energy requirements, and duration of operation;
Comparison of the treatment requirements to the capabilities of
existing facilities.

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Groundwater			
The contamination of groundwater 1s a common occurrence at super-
fund sites. The solution to this problem is often difficult and costly.
Control of groundwater pollution usually starts with the elimination of
the source of pollution. Several approaches are then available to
control the plume of contamination and to remove the contaminants.
Pumping and treatment is often practiced. This technique is often
expensive and can require long periods of time to cleanse the aquifer.
Pumping can also be used to control the migration of the plume. Clean
or contaminated water can be pumped depending on the approach used. In
some cases, pumping, treatment of the water, and relnjectlon have been
practiced, the idea being to enhance and speed up the flushing of the
contaminants from the system.
Subsurface drains and cutoff trenches have been utilized to inter-
cept the groundwater. Barriers, such as grout curtains and slurry
trenches, have been used to isolate the source of pollution or direct
and divert groundwater. The diversion may be of uncontaminated water
away from a source or the control of contaminated water.
Some of the more innovative techniques under consideration are in
situ biological reclamation and chemical treatment. In both cases,
agents are introduced into the aquifer to enhance the degradation of the
polluting material.
At this time I would like to report on a barrier technique that we
field-tested with partial success.
Block Displacement Method
The Block Displacement Method (BDM) is a new method proposed for
complete in situ isolation of contaminated earth materials (Figure 2).
The method involves vertically displacing a mass of contaminated earth,
and in so doing, placing an "impermeable" barrier at the bottom and
sides of the mass. The barrier is formed by pumping slurry composed of
soil, bentonite, or other suitable material into a series of notched
injection holes. A perimeter separation is constructed using one of
several techniques including thin slurry wall, vibrating beam, or a
drill notch and blast technique. Once separation has occurred, the
separation is surcharged with slurry to ensure a favorable horizontal
stress field. The perimeter separation must be constructed at a slight
angle inward toward the block center.
The bottom barrier is formed by drilling injection holes to a
desired depth of the barrier below the waste. The base of the injection
holes is then notched by slurry injection in a horizontal plane. Con-
tinued pumping of slurry under low pressure produces a large uplift
force against the bottom of the block and results in vertical displace-
ment of the block proportional to the volume of slurry pumped.
The BDM was field-tested near Jacksonville, Florida, in 1982. A
block 60 feet in diameter and 23 feet deep was selected for the test.
The site was located in uncontaminated ground adjacent to a contaminated

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14
SLURRY
INJECTION
TTT
yir
INJECTION
' HOLES \
UPLIFT
/ PRESSURE \
PERIMETER
SEPARATION
PERIMETER
SURCHARGE
(WHEN
REQUIRED)
COALESCING
SEPARATIONS
PERMEABLE SOIL
FRACTURED BEDROCK
a) CREATING THE 80TT0M SEPARATION
GROUNDWATER
LEVE1	\	-
PLUME.. J
I
I	<_ PERIMETER
) BARRIER
\ s ",rri\ wr
O \ GROUNDWATER LEVELrM \
\ LOWERED .
BOTTOM BARRIER
POSITIVE SEAL THROUGH
INJECTED 3ENT0NITE
MIXTURE
b) CONFIGURATION Of FINAL BOTTOM ANO PERIMETER 8ARRIERS
Figure 2. Block displacement method-

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15
site. The area was relatively flat and composed of marine sediment of
sllty sand in excess of 100 feet overlaying limestone bedrock. The
groundwater level 1s normally 2 to 5 feet below the surface and a hard
pan layer exists at a depth of approximately 20 feet. The perimeter
separation was made using a notch and blast technique. Six-inch diameter
holes were drilled on the perimeter at 6-foot intervals. Each hole was
notched from top to bottom. Then an 18-inch, 5-foot high concrete
forming tube was placed over each hole and filled with a high density
slurry. All 32 perimeter holes were loaded with prima cord and blasted
simultaneously. Connecting fractures were observed at the surface.
Within the circle, seven injection holes were drilled 23 feet deep
and cased with 6-inch PVC pipe and cemented in place. Horizontal
notches were cut at the base of the holes with a slurry jet notching
tool. Slurry was then injected into the holes. Slurry connection
between holes was observed after approximately 500 gallons of slurry had
been pumped into the central Injection hole. Once separation between
holes was achieved, block displacement proceeded over a 2-week period by
pumping approximately 2 yards per hour alternately into each injection
hole. A resulting upward displacement of the block occurred.
In total, the block was displaced upward approximately 11 inches
at its highest point and tilted approximately 1 degree from horizontal.
A crescent-shaped portion of the block was sheared free of the upward-
moving block and did not move significantly. The block area near the
perimeter lagged the main portion of the block by 3-6 inches in upward
displacement. The crescent-shaped shear zone and perimeter displacement
lag were attributed to an incomplete fracturing and freeing of the block
around the perimeter.
Thin-walled tube soil samples were retrieved and geophysical site
surveys were conducted several weeks after the block displacement. Data
collected indicated that the clay barrier material thickness generally
corresponded to the measured upward displacement of the block of earth.
Observations also suggested strongly that unexpected geologic details of
the site interfered with accomplishment of the barrier placement exactly
according to the design plan.
This field test showed that a bentonite clay slurry could be in-
jected below a site and uplift would occur. The perimeter barrier
construction technique used was unsatisfactory. Other perimeter con-
struction methods should be used in this type of geologic material.
Conclusion
In sunmary, the EPA Office of Research and Development is attempt-
ing to respond to a critical need of the Superfund Program, i.e. re-
liable and cost-effective control technology. Never before has the need
been so great for quick answers to complex problems. In the short run,
we are being faced with utilizing well recognized engineering techniques
that have been used in the past for other purposes and must be adopted
to the uncontrolled waste site problem. In many cases these techniques
are unproven and only through their actual utilization can we determine
their effectiveness, advantages, and weaknesses. In the long run, new
and innovative techniques may come forth and take their place in our
arsenal of weapons to clean up hazardous waste sites.

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