600285105
DECONTAMINATION TECHNIQUES
FOR MOBILE RESPONSE EQUIPMENT USED
AT WASTE SITES
(STATE-OF-THE-ART SURVEY)
by
John P. Meade and William D. Ellis
JRB Associates/
Scientific Applications International Corp,
McLean, Virginia 22102
Contract No. 68-03-3113
Project Officer
Mary K..Stinson
Land Pollution Control Division
Releases Control Branch
Edison, New Jersey 08837
HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
U.S. Environmental Protection Agency
Region 5, Library (F: '
.77 West Jackson EL .. j, r;;\} p:-.^
Chicago, IL 60604O;j
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DISCLAIMER
The information in this document has been funded wholly or in part by
the United States Environmental Protection Agency under Contract No. 68-03-
3113 to JRB Associates/Scientific Applications International Corp. It has
been subject to the Agency's peer and administrative review, and it has
been approved for publication as an EPA document. Mention of trade names
or commercial products does not constitute an endorsement or recommendation
for use.
ii
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FOREWORD
Today's rapidly developing and changing technologies and Industrial
products and practices frequently carry with them the Increased generation
of solid and hazardous wastes. These materials, if improperly dealt with,
can threaten both public health and the environment. Abandoned waste sites
and accidental releases of toxic and hazardous substances to the environment
also have important environmental and public health implications. The
Hazardous Waste Engineering Research Laboratory helps provide an authori-
tative and defensible engineering basis for assessing and solving these
problems. Its products support the policies, programs, and regulations of
the Environmental Protection Agency; the granting, of permits and other
responsibilities of State and local governments'; and the needs of both
large and small businesses in handling their wastes responsibly and
economically.
This report describes decontamination and contamination avoidance
techniques applicable to mobile response cleanup devices which are used at
hazardous waste sites. The information presented in this report is useful
for those who need tp establish procedures for protection and cleanup of
the waste sites' response personnel and equipment.
For further information, please contact the Land Pollution Control
Division of the Hazardous Waste Engineering Research Laboratory.
David G. Stephan, Director
Hazardous Waste Engineering Research Laboratory
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ABSTRACT
A state-of-the-art review of facility and equipment decontamination,
contamination assessment, and contamination avoidance has been conducted.
This review, based on an intensive though short-term literature search and
a survey of various equipment manufacturers, provides only preliminary back-
ground material on the subject. However, the information developed here
constitutes an important "head start" for those who need to establish preven-
tive measures, decontamination plans, and procedures for response personnel
and cleanup equipment used at hazardous waste sites.
The study discusses various decontamination methods, such as use of
solvents to wash off contaminants, use of chemical means to degrade contami-
nants, and use of physical means to remove contaminants. Chemical and physi-
cal testing methods desrgned to assess the nature of the contaminant and the
quantity and extent of contamination were also investigated. Also discussed
in this report are procedures that can be used to prevent contamination of
response equipment and personnel. These preventive procedures are: enclo-
sures to prevent spread of contaminants, safety features on response equipment
to prevent spills and leaks, protective coatings on response equipment sur-
faces, and protective clothing and furnishings for personnel.
Three case studies were also reviewed: the Three Mile Island cleanup,
the "Vulcanus" incinerator ship cleanup {dioxins and PCBs), and PCB cleanups
in Binghamton, New York. The review has identified several methods that
could be of value in effectively decontaminating response equipment units,
such as a mobile incinerator, at a reasonable cost.
This report was submitted in fulfillment of Contract No. 68-03-3113,
Task 3-1, by JRB Associates/Scientific Applications International Corp.
under the sponsorship of the U.S. Environmental Protection Agency. This
report covers the period from April 20, 1984, to May 10, 1984, and work was
completed as of May 10, 1984.
iv
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CONTENTS
PAGE
Foreword iii
Abstract 1v
Tables vi
Figures vi
Acknowledgements . , vii.
1. Introduction 1
2. Conclusio.ns and Recommendations 5
3. Contamination Avoidance 6
Enclosed Structures and Secondary Containment 6
Equipment Safety Features 9
Protective Coatings .. 11
Personnel Protective Clothing and Equipment . 13
4. Assessing Contamination Levels 20
Chemical and Physical Tests 20
5. Decontamination Methods for Mobile Response Equipment ..... 28
Solubilization Methods (use of solvents) . 28
Chemical Degradation of Surface Contaminants 37
Physical Decontamination Techniques 44
Abrasive Cleaning Methods 44
Non-Abrasive Physical Cleaning Methods 49
6. Case Studies: Decontamination of Surfaces 56
Decontamination of the Binghamton State Office Building ... 56
M/T Vulcanus Decontamination 58
Three Mile Island Decontamination . •. 59
Case Studies Conclusions 60
References 62
Appendix
A. Factors for Unit Conversion 66
- v -
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TABLES
NUMBER
1 Summary of the Use of Protective Coatings for
Prevention of Surface Contamination 11
2 Gunk Decontamination Preparations 30
3 Summary of Sol utilization Methods for Removal of —
Surface Contaminants . 38
4 Summary of Chemical Degradation Methods for Removal
of Surface Contamination 40
5 Summary of Abrasive Methods for Removal of Surface
Contaminants 45
6 Summary of Non-Abrasive Physical Cleaning Methods for
Removal of Surface Contamination 52
7 Vacuum Vendors 54
FIGURES
NUMBER PAGE
1 Mobile Incinerator Components 25
vi
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ACKNOWLEDGEMENTS
The technical direction of Mary K. Stinson, U.S. Environmental Protection
Agency Project Officer, is greatly appreciated. The authors also wish to
acknowledge the cooperation and assistance of the following persons and firms
who have contributed to the development of this survey.
Mr. Karl Ashley
Health Physics, Inc.
Mr. John HawTey
New York State Department of Health
Mr. Norman Higgins
Eastern Cleaning Equipment
Mr. James W. Phillips
Nilfisk of America, .Inc.
Mr. Dave Rings
New York State Office of General Services
Mr. Jim Trembley
Harding Lawson Associates
Mr. Bob Westin
Versar, Inc.
vii
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SECTION 1
INTRODUCTION
GENERAL OVERVIEW
The purpose of this document is to provide Environmental Protection
Agency (EPA) and other waste site response personnel with background infor-
mation on contamination avoidance and decontamination methods applicable to
mobile response hazardous material cleanup devices used at waste sites.
The document emphasizes preventing contamination of the response personnel
and the mobile response equipment, taking into consideration public health
and safety, cost, and efficiency.
This document which is based on an intensive literature search and
survey of various equipment manufacturers, represents preliminary background
information on the subject. This information constitutes an important
"head start" for those who need to establish preventive measures, decontam-
ination plans, and procedures for response personnel and cleanup equipment
at hazardous waste sites. This information has already been used in the
field by the Releases Control Branch of the EPA Hazardous Waste Engineering
Research Laboratory (HWERL), and by EPA contractors of the Laboratory.
The Releases Control Branch has developed a wide variety of prototypical
hazardous material cleanup devices. This specialized, full-scale mobile
equipment is capable of performing many useful and complex, hazardous chem-
ical cleanup and treatment processes at spill sites and Superfund hazardous
waste sites. These mobile response devices are deployed by EPA's Environ-
mental Emergency Response Unit (EERU) contractor at spill and waste sites,
where the equipment undergoes field demonstrations and shakedown tests.
One example of an EPA-developed mobile response unit is the Mobile Incin-
eration System ("Mobile Incinerator") which underwent test burns of dioxin-
contaminated soils. The unique feature of the EPA developed incinerator is
its mobility, which facilitates its transport to waste sites.
The use of the mobile response devices at spill and waste sites inevit-
ably leads to contamination of the devices, and their operators, with hazardous
chemicals being treated. Subsequent relocation of the mobile devices may
spread the contamination to the surrounding community unless controls,
including contamination avoidance and decontamination procedures, are used.
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Fields ContVibuting to the State-of-the-Art. on Cleaning Contaminated
Surfaces
Surface decontamination methods generally rely on techniques which are
applicable to treating an assortment of hazardous substances. There are
many areas which demand surface decontamination. They include:
o Nuclear waste activities
o Chemical/biological warfare agent cleanup
o Chemical process equipment cleaning
o Drum recycling.
Many methods that are presently used in these areas could very likely be
extended to the decontamination of mobile response equipment.
The following sections discuss the importance of decontamination con-
cepts relative to different fields of application. The decontamination
procedures are described here in general terms. They will be addressed in
greater detail in Sections 4 and 5, below.
Nuclear Waste Activities
The discharge of radioactive substances to the environment is the
central hazard associated with nuclear reactors. Such discharge can occur
while the reactor is in operation or when it is shut down. Maintenance of
the reactor often demands removing corrosion scale from inside pipes and
tanks, and these products can be radioactive. When a surface that requires
decontamination has an oxidized (rust) or corroded coating, it becomes
Irregular, having much more total adsorptive surface area than a non-oxidized,
uncorroded surface, and can therefore hold more contamination. Removing .
the oxide or corrosion therefore facilitates contamination removal. Decon-
tamination reduces radiation levels to ensure personnel safety. It also
keeps reactor operation at efficient levels.
Chemicals seem to be the primary agents for cleaning nuclear equipment.
Various methods and formulations exist and have been tested. Selection of
the appropriate method depends on the type of problem to be solved. The
following list may offer general guidance (1):
o Reduca radiation levels
o Dissolve the oxide film
o Prevent reprecipitation and redeposition of products
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o Have minimal corrosion effects
o Provide treatment with a single application.
Chemical/Biological Warfare Agent Cleanup
The U.S. Army has conducted a number of studies on the problems asso-
ciated with military personnel and equipment contamination by chemical and
biological warfare agents. A chemical agent's effect depends on the type
and amount with which the individual comes into contact, and the person's
physical condition. Biological agents are living organisms that cause
disease to the exposed individual. Again, effects depend on the agent and
the individual's susceptibility. For either situation, avoiding exposure by
using protective clothing and a gas mask is a prime consideration. Decon-
taminating an individual and his clothing (or outer protective garments)
following a chemical/biological exposure temporarily removes the individual
from danger.
Exposure to contamination that covers equipment surfaces, which occurs
when using mobile response equipment at hazardous waste sites, remains a
problem. Decontamination procedures may include rinsing the surfaces with
water, detergent, or solvent, or removing the agents by physical methods such
as high pressure water. In the case of biological agents, chemical methods
are needed to destroy the disease-bearing organisms. Chemical methods are
also used to detoxify chemical agents; they are particularly effective in
penetrating the oily residues in which most agents survive.
Chemical Process Equipment Cleaning
The efficient operation of a chemical production process often depends
on maintaining the purity of the streams as they pass through reaction ves-
sels, separation units, assorted pipes, valves, and .pumps. Corrosion prod-
ucts, dirt and oxide layers, and even vapors condensed upon inner surfaces
of equipment may interfere with product quality, reaction performance, or
the achievement of adequate rates of chemical transport from one process :
unit to the next. Likewise, auxiliary equipment such as cooling towers or
heat exchangers operates best when corrosion and fouling are minimal.
Removal of internal buildup is only one reason for decontamination.
Often an industry produces two or more products using the same process equip-
ment. The equipment must be emptied and cleaned of all compounds (e.g., raw
materials, intermediates, products) associated with the initial process so
that foreign chemicals do not contaminate the subsequent process.
Chemical process equipment may also have to be cleaned prior to mainten-
ance or removal from service. Cleaning the equipment before transport
reduces the spread of contaminated material. Methods for decontamination are
numerous. Chemical methods can circulate .cleaning fluids throughout the
system. Removable portions can be cleaned in immersion tanks or by physical
methods. The interiors of large vessels often can be cleaned by physical
methods such as high-pressure water or abrasive cleaning.
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Drum Recycling
Storing chemicals In drums or other containers is a common practice.
Sorting and transporting filled drums may affect personnel safety; however,
empty drums also present a number of problems. Empty drums are often re-
cycled, and total removal of chemicals from drums is difficult.
Using a drum to store a chemical that it previously contained isn't a
problem, but there are hazards if a drum is to be filled with a different
chemical. Decontamination must be carried out to assure that no traces of
chemicals from prior uses remain. Drums may be immersed in or flushed with
water or appropriate solvents. Physical methods of cleaning, such as
abrasive blasting, are also common.
Case Studies
The following three case studies are discussed in Section 6 (page 56)
of the report: (1) cleanup of the Binghamton Sta^e Office Building in
Binghamton, NY; (2) "Vulcanus" incinerator ship cleanup (dioxins and PCBs);
and (3) the Three Mile Island cleanup. As a consequence of reviewing these
case studies, several methods and techniques that have applicability to
decontaminating mobile response units at hazardous waste sites have been
identified. "
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
FINDINGS
The decontamination and contamination avoidance methods discussed in
this report, including physical and chemical cleaning methods, protective
coatings, personnel protective clothing and equipment, and containment
structures, have a wide range of advantages. The following paragraphs
outline several promising decontamination scenarios, based on combinations
of the methods described in this report.
Seamless surface coatings of heat and chemically resistant, durable
polymers increase the ease and effectiveness of most decontamination methods
for mobile response units. Also, presence of a drainage and collection
system beneath mobile units for containing rinses and other surface cleaning
wastes will facilitate the decontamination process.
Decontamination can be simple. Vacuuming can effectively remove gross
contamination, such as particulates, from surfaces. Final decontamination
may then be accomplished using either detergents and high pressure water or
wet abrasive blasting. Spent wash and rinse waters may be collected and
properly stored for incineration or off-site disposal.
Vacuuming or an initial water rinse to remove gross contamination,
followed by the application of a solvent or acid-based foam or gel, is
another approach. After allowing time for contaminant solubilization, the
formulation may be rinsed off and collected for disposal. This process may
be repeated to accomplish sufficient decontamination.
Areas of mobile response units that are most heavily contaminated,
such as the loading area and hopper system of the mobile incinerator, may
be stripped to bare metal to ensure the highest level of decontamination.
One of the most promising techniques is exposure to high intensity UV light
or flash blasting, which destroys contaminants at temperature flashes of
2,760°C. In some cases, heavily contaminated areas may be disassembled and
cleaned separately via high pressure FREON" or ultrasonic cleaning.
Tables 1 through 5 summarize methods of decontamination and contami-
nation avoidance. Applications, limitations, and capabilities of each method
are also presented.
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SECTION 3
CONTAMINATION AVOIDANCE
INTRODUCTION
To maximize the effectiveness of decontamination procedures, chemical
manufacturing industries commonly apply methods that reduce or prevent
contamination of equipment at hazardous waste sites. This section will
investigate various methods which can be applied to avoid contamination of
mobile response equipment during its use at waste sites. Specifically,
this section provides descriptions of the following methods for avoiding
contamination:
o Enclosed structures and secondary containment for the mobile
response units
o Equipment safety features
o Protective coatings for the mobile response equipment
o Personnel protective clothing and equipment.
ENCLOSED STRUCTURES AND SECONDARY CONTAINMENT
Enclosing or containing operating equipment is a principal means of
minimizing exposure of surrounding communities or properties to hazardous -;
materials during operation. This can be accomplished through 1) enclosure
(i.e., overhead structure) of the mobile response equipment to minimize air
transport of materials, and 2) secondary containment, such as dikes, drainage
systems or lined impoundments around potential points of release to minimize
surface transport of materials.
Enclosures and secondary containment can be applied alone or together
to cover the entire mobile response system, or only those components that
are potential sources of significant release (e.g., feed system, ash collec-
tion on a mobile incinerator). Constructing an enclosed structure with
some level of secondary containment would limit the contaminated area to a
relatively small area, thereby reducing the efforts required for decontami-
nation of the mobile response unit and its surroundings.
A variety of commercially available systems for enclosing large areas
have found application in the waste management industry. Also, various
secondary containments can be applied to the mobile response systems wherever
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spills are prevalent. The following sections provide a brief summary of .
enclosed structures and secondary containment methods. Examples of such
systems, approximate costs, and limitations of implementation are provided,
where possible.
Enclosed Structures
Using a structure to house the mobile response system can significantly
reduce contamination of surroundings during the unit's operation. Fugitive
emissions during operation could be contained within the enclosed structure,
enabling rapid cleanup before dispersion of contaminated material occurs.
Careful study must be given to the potentially increased concentration of
contaminants within the building structure, which could increase the poten-
tial for worker exposure. Enclosed structures are considered here as a
means to limit spreading contaminants during operation through air, rain-
water, and spill transport mechanisms.
The following criteria were used in evaluating enclosed structures:
o Area covered by the enclosure
o Ease of installation and maintenance
o Economics.
9
One type of commercially available enclosure is an air inflatable struc-
ture. This type of building may have an inside clearance ranging from 20 to
30 meters, depending on the manufacturer. These buildings can be designed to
have a clear span up to 90 meters and a length of 240 meters. The building
is kept inflated with a series of fans for which most manufacturers provide
backup generators in case of power failure. The building can be easily
anchored to a 1-meter wide, 1-meter deep continuous grade beam. These struc-
tures can be easily relocated by pouring a new foundation. The capital costs
quoted by representative vendors vary from $30 per square meter (Thermo-flex)
to $100 per square meter (Bird Air Inc.) Special care must be taken to
separate the mobile response unit from the rest of the waste site to prevent
the accumulation of hazardous levels of combustion byproducts from building
up inside the structure. The mobile response unit, especially the mobile
incinerator, must be kept in a well ventilated area to prevent the accumu-
lation of gases and particulates.
Arch structures are another type of commercially available enclosure
which provides greater structural support than typical air-supported struc-
tures. Arch structures are made of steel with 50-meter spans (Wonder Buil-
dings). The lengths of these buildings are virtually unlimited, and heights
vary from 6 to 18 meters. These buildings are easily relocatable and have
minimal operating and maintenance costs. Capital costs for this type of
structure range from $100 to $200 per square meter.
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Conventional prefabricated-type construction could also be applied. A
"Butler" pre-englneered steel building has a span of 36 meters with a 7-
meter high cave, and is 90 meters long. Although it 1s perhaps the easiest
building to construct and one of the most permanent, its relocation is
rather difficult. Costs vary from $80 to $100 per m2. The building would
have to be demolished and removed after the job is completed, and treated as
hazardous. The "Butler" type building also prevents negative pressure, which
is a condition that can occur in an air supported or totally enclosed buil-
ding when, as in the case of the mobile incinerator, primary and secondary
combustion create heavy demands for air. High negative pressure should be
avoided since it would tend to starve an incinerator of oxygen thus causing
incomplete combustion. Low negative pressure can be beneficial however,
since this would cause fugitive emissions to be contained.
Fabric supported by an arch system could also be applied. Polymer
fabrics such as a polyester material manufactured by Thermoflex are commonly
available for this use. These buildings need relatively small foundations
and are easy to relocate. The initial costs range from $200 to $400 per m2.
The enclosed structures will become hot inside and may be very uncomfor-
table for the workers; therefore, some type of ventilation system should be
installed to assure tolerable working conditions. Although it costs from
$100 to $200 per m2, an arch structure would provide a comfortable enclosure.
It is easy to install and has minimal operating and maintenance costs.
.Secondary Containment Methods ; . .
Secondary containment is a commonly applied spill control measure em-
ployed by industrial and manufacturing facilities. Secondary containment
systems are typically lined areas (concrete, metal, clay, polymer lining
materials) that provide a catchment for inadvertently spilled or leaked
materials, minimizing their escape across the surface or through the soil.
They provide temporary containment, allowing spilled materials to be cleaned
up before they contaminate surrounding environments.
Secondary containment applied to the mobile response unit during oper-
ation can protect against hazardous material leakage to surroundings. Con-
tainment can be applied areawide (i.e., around the entire unit) or at points
in the unit where leaks or spills are most prevalent (e.g., feed system,
ash collection system in a mobile incinerator).
A simple, effective secondary containment measure is a 20 centimeters
sloped combed concrete slab, The slab can be coated by an impermeable
polymeric material, such as polyviny] chloride (an epoxy resin), to minimize
hazardous material permeating the concrete. The slab can be sloped into a
collection sump to ease collection of spilled materials and wash water off
the pad. Any spilled material would collect in the sump and be pumped using
bulk tank vacuum pumps. The cost of a concrete pad for the incinerator unit
is estimated to be $8,200 for a pad with dimensions of 50 m x 5 m x .22 m.
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Containment method with the "Butler" type building would possibly be the best
alternative for construction on waste sites, due to low costs and ease of
construction.
Another effective technique would use a polymeric fabric cover. The
cover could be placed over the immediate area in which the mobile response
system is operating. The cover, made of an impervious material (i.e., poly-
urethane or high density polyethylene), could be placed over a compacted fill
area. To avoid any tears in the fabric, plywood planks should be laid as
tracks for the wheels. The fabric cover could then be collected and in-
cinerated. Although not as structurally sound as a concrete containment
system, this system is easy to install, remove, and clean up.
Consideration should be given to selecting the secondary containment
scheme. For most applications, a concrete pad would provide good structural
support for the mobile response unit; it would be easy to clean if coated,
and it would be relatively inexpensive. ..
EQUIPMENT SAFETY FEATURES'"
An effective way to avoid contamination of the mobile response unit
exterior and reduce decontamination efforts is to consider design options
which incorporate safety or leak minimization features. This section will
review the engineering design of the mobile response equipment and point out
possible causes of failure based on industry experience. A study conducted
by the National Institute of Occupational Safety and Health (NIOSH) April,
1981, has concluded that in petroleum refineries and other chemical proces-
sing industries, a major source of worker exposure to hazardous chemical
compounds are fugitive emissions (gaseous and liquid) from seal and fitting
components of the chemical processing equipment employed.
The reality of the imperfect and variable performance of chemical pro-
cess equipment seals and fittings makes preventing fugitive emissions
difficult. To reduce fugitive emissions, equipment components using seals
and fittings should be examined to:
o Identify potential sources of emission within the equipment
o Recommend changes in the equipment to reduce emissions.
A discussion of process equipment employing seals or fittings follows.
Industry uses a variety of pumps, including centrifugal, positive dis-
placement, reciprocating, piston, rotary, diaphragm, and screw pumps. The
source of emission from most pumps is the drive shaft seal (2). The func-
tion of the drive shaft seal is to prevent fluid from escaping through the
clearance between a rotating shaft and the wall or a housing or pressurized
vessel.
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Common causes of failure in mechanical seals Include: Incorrect seal
assembly, Improper materials or seal design, fluid contamination, poor equip-
ment conditions, and worn-out seals. The leakage rates are normally small;
nonhazardous or nontoxlc fluids may quickly evaporate or dissipate Into the
atmosphere. However, pumps for hazardous and toxic fluids require other
means to contain contaminants (3).
To contain hazardous materials, most pump manufacturers serving the
Chemical Process Industry offer double or tandem seals to control fugitive
emissions. The bellows-type seal 1s common in many applications; 1t is con-
sidered safer and less prone to trouble and leaks than other types of seals
(4). Another containment procedure uses magnetic drive pumps without seals.
These pumps have no shaft that could wear, leak, need replacement, or reduce
power. A magnetic coupling acts as a clutch to eliminate overload and motor
burnouts. Magnetically driven pumps are available in a variety of capaci-
ties. Ratings range from 30 gpm pumps to giant-drive pumps that are rated
at 5,000 Ib/in2, and operate in temperatures of -200° to 260°C. Jacketed
design of custom centrifugal, axial flow, and canned rotor high-pressure or
high temperature pumps are other possibilities for fugitive emission control.
Hermetically sealed, these zero-leakage pumps offer the advantages of opera-
ting temperatures from cryogenic to 540°C, pumping rates from 30 to 1,200
gpm, and standard design to handle 340 atm.
Seal-less slurry and acid pumps that have no packing, water glands, or
mechanical seals continue to find special service applications in the
Chemical Process Industry. These pumps do not leak while running because a
secondary set of pumping vanes (expellers) creates a hydraulic seal. The
expeller keeps liquid out of the shaft as the impeller pumps material
through the discharge. As the pump shuts down, powerful springs close the
two seals. A drip pan may be used for additional safety (4).
Valves
Valves serve not only to regulate fluid flow, but also to isolate piping
or equipment for maintenance without interrupting other connected units. {
Various valves used in industry are: gate, globe, angle, butterfly, ball,
and diaphram valves. The emission sources associated with most valves differ,
depending on whether the valve is placed in-line or is open-ended. If the
valve is in-line, emission sources are the stem and bonnet of the valve. If
the valve is open-ended, emission sources are the stem, bonnet, and flow seal
(2).
Industry has opted to use pack!ess-type valves to reduce fugitive emis-
sions. Two options are investigated. 1) Bellows sealed valves use a bellows
for leak-tight service. The bellows are manufactured from ductile metal
tubing. By sealing one end of the bellows to the valve stem and the other
end to the valve body an all metal seal is achieved while maintaining vertical
movement of the valve stem. These pack!ess bellow-seals permit zero leakage
past the stem. 2) Diaphragm valves are excellent for fluids containing
suspended solids. The fabric reinforced diaphragms may be made from natural
rubber, synthetic rubber, or natural or synthetic rubber faced with Teflon«.
Diaphram valves are, however, limited to pressures of approximately 3.4 atm.
(5).
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Piping Systems
Piping systems are another area where fugitive emissions may occur
during process operations. Piping systems incorporate flanges, elbows and
tees, straight piping sections and various other types of fittings. Because
fugitive emissions occur at these fittings, designing piping systems requires
careful consideration. For example, a slurry transport pipeline should be
designed to minimize sharp elbows and turbulent flow patterns (2); as this
increases the severity of corrosion.
Other considerations when specifying a piping layout would be to use
high temperature, high pressure seals at pipe joints. And using other pipe
materials such as stainless steel or Inconel, since these materials resist
corrosion well. Incorporating a pipe monitoring plan, using X-ray or special
metallographic examinations should also be considered when installing a
piping system. Installing drip pans around pipe joints and valves is an
effective method of monitoring for leaks or faults in the piping system. In
essence, incorporating equipment safety features in the mobile response
apparatus effectively avoids contamination.
PROTECTIVE COATINGS
The chemical industry typically applies paint to protect surfaces
against corrosive chemicals. Use of paint minimizes contaminating metal
surfaces and provides a surface that can be easily removed or cleaned to
eliminate settled contaminants. These coatings must be selected according
to how easily they are applied, decontaminated or cleaned (See Table 1).
TABLE i. SUMMARY OF THE USE OF PROTECTIVE COATINGS FOR PREVENTION
OF SURFACE CONTAMINATION
REMOVAL OF BASE METAL
AREA OF APPLICATION
QUANTITY OF WASTE PRODUCED
WORKER EXPOSURE
OVERALL COSTS
COMMENTS
PERMANENT COATINGS
Negligible
External
Moderate
Low
Moderate
Easily applied with a
brush, spray system,
or roller.
TEMPORARY COATINGS
Negligible
External
Moderate-Large
Low-Moderate
Moderate-High
2 or more coats needed,
allow over 24 hours to
cure.
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Surface contamination can originate from a number of sources: (1) Ab-
sorption of impurities (e.g., hydrocarbons) from the ambient air, (2) Reac-
tion of the surface with the reactive species (e.g., oxygen, sulfur), and
(3) Preferential diffusion of one component (in case of multi-component
materials), which can cause variable composition-type surface contamination.
The contaminants caused by these sources are film or layer-type in nature
(6).
Generally, decontamination by either chemical or physical means effec-
tively removes materials such as soils, chemical compounds, metal fines, and
reaction products from a surface. Surface contaminants can be removed chemi-
cally by strong reagents (acids, alkalis) that simultaneously prevent their
redeposition. Physical methods range from abrasion to ultrasonic cleaning.
(See Section 5 for a discussion of cleaning methods).
Experience has shown that surfaces (metal, concrete, etc.) overlaid
with a protective coating are easier to decontaminate (7). These coatings
can be either permanent or temporary. Available coatings are discussed
below.
Permanent Protective Coatings
Permanent protective coatings are polymeric materials that can be ap-
plied to metal and other surfaces for long-term use. They are intended to
provide an easily decontaminated surface that protects migration into struc-
tural materials. These coatings could remain on the equipment for many
years without removal. The criteria used in the selection of a suitable
permanent coating are:
o Resistance and compatibility to environmental dusts and vapors
o Ability to withstand chemical and physical decontamination
procedures
o Ease of application
o Adherence (adhesiveness) to the metal surface.
Based on these criteria, the following coating materials are candidates for
permanent coatings:
o Epoxy Resins
o Phenolic Resin Coatings
o Chlorosulfonated Polyethylene
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Temporary Coatings
An envelope of a polymeric material that can be peeled off or removed
1n some other way can often meet the requirements for temporary protective
coatings. These coatings protect the enclosed metal from corrosion and mech-
anical abuse. Because they can be peeled off and subsequently Incinerated,
temporary coatings do not require the physical and chemical decontamination
methods that permanent coatings do. The following can be used as temporary/
strippable protective coatings:
o Chloride acetate copolymers are most suitable for strippable sur-
face coatings. An effective coating used in many applications is
composed of a plastic spray in solution of copolymers. This
coating can withstand a variety of chemical environments, and after
use, it can be easily stripped and incinerated (10).
o In certain instances, layered coatings, one layer of which can be
selectively dissolved and removed from another without ruining the
base coating,'may be needed to facilitate decontamination. An
epoxy overlaid with polyvinyl chloride (PVC) is such a combination.
Other combinations include PVC over modified phenolic, epoxy poly-
amide cured, and inorganic zinc (7).
o Plastics employed as strippable coatings are largely vinyls, cellu-
lose acetate, ethyl cellulose, or cellulose acetobutyrate. They
have been used 1n a variety of Industries and can easily be
stripped and incinerated (11).
o Polyurethane is also a good temporary protective coating. It
shows high chemical resistance and is durable. Polyurethane
coating can be sprayed or brushed on and is easy to remove.
o For small areas, protective tapes can prevent contamination. -I
Tapes made of polyvinyl chloride, polyethylene, and fluorocarbons
are used in various industrial operations. These tapes can
easily be stripped and incinerated.
A variety of permanent and temporary protective coatings have been inves-
tigated in this section. Although there are other coatings available, they
are less effective and more expensive. Based on the coatings investigated,
layered coatings using an epoxy overlaid by PVC seem to be a promising tech-
nique to protect mobile response equipment.
PERSONNEL PROTECTIVE CLOTHING AND EQUIPMENT
The temporary nature of hazardous waste site work eliminates sophisti-
cated engineering controls (such as piped ventilation systems) as feasible
methods for preventing or controlling worker exposure to toxic materials.
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Instead, safe work procedures and personnel protective clothing and equipment
must be used. How successfully work procedures and protective clothing guard
worker health depends on worker cooperation. Carefully prepared standard
operating procedures (SOPs), effective employee training, and supervisory
enforcement of the safety and health plan are necessary to maximally protect
each worker from toxic exposure.
Various safety equipment will be required during the field work assoc-
iated with mobile equipment operation and decontamination of mobile equipment.
Because of the variety of the tasks to be performed and their associated
exposure levels, it would be prudent to determine a standard for the level
of protection necessary for each phase of operation. The following sections
discuss:
o Guidelines for determining levels of protection necessary for
various potential exposure situations
o Selection and use of personal protective equipment in accordance
with the guidelines
o Temporary emergency response
o Mobile decontamination units.
Levels of Protection
The Office of Emergency and Remedial Response of the U.S. Environmental
Protection Agency has prepared final standard operating safety procedures
for hazardous waste spill site control and entry. The following discussion
and the system for selecting protective equipment based on 'four levels of
protection are adapted from the SOP of EPA's Emergency and Remedial Response
Division, 1985 (8). I
Insufficient knowledge of toxicity levels at a particular site pre-
cludes advance selection of any but the highest level of personnel protective
equipment. Initial estimates of the toxic and hazardous wastes (including
carcinogens) at a site must be empirically determined to ensure worker
safety. This may be modified after adequate data is collected on the actual
levels of toxicity.
Level A Protection
Level A protection should be worn when the highest level of respiratory,
skin, and eye contact protection is required; exposure to toxic materials
can cause illness. Situations warranting this level of protection should
be remedied by removing the inherent hazard through mechanical means,
engineering design, or structural enclosures.
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However, should this high level of protection be imperative, the
personnel protective equipment required for Level A protection Includes:
o Positive pressure self-contained breathing apparatus (SCBA)
operated in the positive pressure mode
o Totally encapsulating chemical resistant suit
o Gloves—inner (tight-fitting and chemical-resistant)
o Gloves—outer, chemical-resistant
o Boots—chemical resistant, steel toe and shank
o Hard hat—optional.
Level B Protection
Level B protection should be selected when either the highest level
of respiratory protection is needed but exposure to the small unprotected
areas of the body (i.e., neck and back of head) is unlikely, or toxicity
concentrations are within acceptable exposure standards. This level of
protection is essential if worker illness through exposure is likely.
Similar to the Level A protection, Level B protection is appropriate
only in extreme cases when other alternatives are not feasible.
Personnel protective equipment required for Level B protection includes:
o Positive pressure SCBA operated in the positive pressure mode
o Hooded, two-piece, chemical-resistant-type coverall suit
o Gloves (inner and outer)—chemical resistant
o Boots—chemical resistant, steel toe and shank
o Hard hat—optional.
Level C Protection
Level C protection should be selected when: (1) the type(s) and
concentration(s) of respirable material are known, (2) the material has
adequate warning properties or is assumed to be less than the protection
factors associated with air-purifying respirators, and (3) exposure to the
few unprotected areas of the body (i.e., neck and back of head) 1s unlikely
to cause harm.
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Personnel protective equipment required for Level C protection Includes:
o Full-face, air-purifying cannister or cartridge respirator
(full-face respirator can be worn instead of non-vented goggles
if eye irritants are present)
o Safety goggles (non-vented if not full face respirator)
o Chemical-resistant clothing
o Hooded, two-piece, chemical-resistant Tyvek coveralls
o Gloves {inner and outer)—chemical resistant
o Escape mask
o Hard hat—optional
o Boots—chemica/l resistant, steel toe and shank.
Level D Protection
Level D is the basic work uniform and should be worn for all site
operations not requiring greater protection. Level D is appropriate only
when sites are positively identified as having minimal toxic hazards.
Personnel protective equipment required for Level D protection includes:
o Chemical-resistant Tyvek coveralls
o Boots/shoes--safety or chemical-resistant, steel-toed boots
o Escape mask
o Safety glasses or safety goggles
o Hard hat (face shield optional)
o Half-face cannister or cartridge respirator (carried)
o Gloves (carried).
The Selection and Use of Personnel Protective Equipment
The Site Health and Safety Officer (SHSO) should determine the level
of protection necessary for each operation, based on a discussion of condi-
tions with the Project Leader. Through periodic inspections, the SHSO will
ascertain that the users of the equipment are maintaining its effectiveness
through regular care, cleaning, and repair according to the manufacturer's
instructions.
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Boots must be worn at all times at all sites. The boots should be leak
proof, chemically resistant, and steel-toed. These boots preferably should
be the type which directly covers the foot (with socks), rather than another
boot.
The gloves must be leak proof and chemically resistant. The glove
material should be chosen based on the waste constituents expected at the
site. In the absence of such information, the gloves should be neoprene or
nltrlle rubber. Nothing at the site should be touched without gloves. For
warmth, cotton gloves may be worn underneath. Clean surgical gloves should
be worn under the neoprene gloves. A two-glove system is standard practice,
with the second glove serving to remove other articles of clothing during
the decontamination process (EPA Peer Review, 1985).
Some type of eye protection shall be available for all operations.
Non-vented goggles should be worn in the presence of irritating vapors.
These goggles should be chemical and splash-resistant. Half-face respira-
tors should be worn with goggles for eye protection. The goggles must fit
snugly and not interfere with the respirator seal. When not in use, the
goggles may be worn on the safety helmet. When irritants are not present
and a full-face respirator is not required, safety glasses or vented goggles
may be worn to protect eyes from flying objects or liquid splashes.
The coveralls should be splash repellent and chemically resistant.
Disposable Tyvek coveralls are successful for this purpose and cost around
$4-$5 each. Other suits such as PVC or vinyl (raingear) can also be worn
in Level "B" or Level "C" protection. Fully encapsulating reusable suits
(usually butyl rubber) should be worn in confined areas that may contain
toxic substances (e.g., the temporary enclosed structure of mobile response
equipment), and in areas where toxic substances that are absorbed through
the skin are present. The costs of fully encapsulated reusable suits made
of Chloropel* range from $5,351 per suit (Lab Safety Supply), to $670 per
suit (Preiser/Mineco).
Three types of respiratory protection must be available to the site
workers: half-face cannister or cartridge respirators, full-face cannister
or cartridge respirators, and self-contained breathing apparatus (SCBA).
The SHSO should inspect all SCBAs and other protective gear weekly, whether
used or not, and should keep a written record of the inspections.
Disposable protective equipment is well-suited for many decontamination
procedures since extensive cleaning or reconditioning of the equipment after
use is unnecessary. Disposable gear especially useful in decontamination
operations include: Tyvek coveralls, various hat and shoe covers, shoulder-
length plastic gloves, durable plastic gloves of all types, lightweight
plastic jackets and trousers, boots of all types, and air purifying cartridge
and filter respirators.
An effective procedure for cleaning reusable protective clothing is to:
(1) place the protective gear in a rinse tank containing a solution of warm
water and a compatible soap or detergent (Alconox), (2) scrub the gear with
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a brush, and (3) thoroughly rinse the clothing with clean Mater. For
respirators, NIOSH recommends that the mask parts (with filters removed)
be placed in a 5 percent solution of sodium hydroxide or a strong alkaline
solution for 1 or 2 minutes, followed by a thorough rinse with clean water.
Cleaning mask parts with a cleaner-sanitizer, such as a dilute solution of
ethanol, is also possible (2). Another commonly used cleaning method in the
field is an alkaline wash (sodium carbonate and detergent or Borax and deter-
gent) followed by a fresh water rinse (using a quaternary ammonium chloride
instead of alcohol) and air drying (EPA Peer Review, 1985).
Other cleaning techniques employed are: (1) using a commercial dish-
washer for cleaning respirators, and (2) using a standard domestic-type
clothes washer with a rack installed around the agitator to hold the face
pieces in fixed positions. In both cases any good detergent may be used,
but cleaner-sanitizer solutions are more effective.
Mobile Decontamination Units
Personnel protective equipment 1s very important in controlling worker
exposure to the toxic environment. However, protective clothing can accumu-
late contaminants on the surface. Therefore, the worker needs to go through
a decontamination process before leaving the site. This prevents workers
from carrying residual chemicals home and thereby exposing their families.
Methods have been established to eliminate this hazard. Maximum and minimum
standards have been set which should be strictly enforced. The minimum
requirement for Levels A, B, and C require stations to be set up to perform
each task listed below:
1. Place all equipment used on-site (tools, sampling devices and
containers, monitoring Instruments, radios, clipboards, etc.) on
a plastic dropcloth. Keeping equipment separated at the site will
prevent cross contamination.
2. Scrub outer boots, outer gloves, and suit with decontamination
solution or detergent and water. ' Rinse well with water.
3. Remove outer boots and gloves. Drop in plastic-lined container.
4. Exchange workers' air tank or canister (mask), put on new outer
gloves and boot covers, tape all joints.
5. Remove boots, suit, and inner gloves and deposit them in separate
plastic-lined containers.
6. Remove breathing equipment. Avoid touching face with hand.
Deposit in plastic-lined containers.
7. Wash hands and face thoroughly. Shower as soon as possible.
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Another effective decontamination process 1s the use of mobile decontam-
ination units. The worker enters the decontamination unit, passes through
the contaminated change area, and gets out of the protective equipment. Next,
the worker proceeds to the showers, which can be somewhat effective 1n removing
particulates left on the body. After showering, the worker enters a clean room
and dons his street clothes.
Evergreen Industry provides mobile decontamination units. Each unit is
made of aluminum and 1s fully insulated; it features a negative-pressure
blower system with a high-efficiency filter for clean emissions. It also
features a holding device for wastewaters generated by cleaning of equipment
and personnel.
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SECTION 4
ASSESSING CONTAMINATION LEVELS
INTRODUCTION
Decontamination of surface-contaminated substances involves the chemical/
physical removal or destruction of harmful substances from solid surfaces
(soil, metal, wood, glass, etc.) or from the air*. After the contaminated
area and associated components are identified; a series of chemical/physical
tests are performed to quantitatively measure the levels of contaminants
present in the subject area. Before initiating decontamination operations, a
detailed work plan specifying the procedures, analytical techniques, and
safety criteria to be employed should be'prepared. The final step is to
implement the procedures and analyses as specified in the decontamination
plan.
CHEMICAL AND PHYSICAL TESTS
The chemical/physical test(s) initially performed to detect the presence
of hazardous contaminants should consider:
Determination of an acceptable level of decontamination
Specific sensitivity — the degree of sensitivity/accuracy
attainable by the test and its ability to meet the required
detection limits.
Ease of application — the ability of in-house personnel to
perform the test.
Level of analysis — whether the sample test results can be
analyzed oh-site using a mobile laboratory and in a reasonable
amount of time.
Portability of equipment — whether the test equipment is capable
of being used in the field. Whether the test equipment requires
any special services (electricity, plumbing, ventilation, etc.)
Samples handling -- the requirements for sample preservation and
transportation.
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Chemical and physical tests for contaminant analysis are categorized
Into surface tests and Instrumental tests. Both categories are described
In more detail 1n the following sections.
Surface Tests
Tests that verify whether surfaces are contaminatd with specific sub-
stances are an important component of the decontamination procedures. These
tests utilize chemical solvents, water, and ultraviolet light as sampling
media. The surface tests are typically performed manually or by the use of
visualization reagents.
One form of surface test utilizes a substrate which is Impregnated with
an appropriate solvent (ethanol, benzene, water, etc.). First, the impreg-
nated substrate is wiped onto the test surface to absorb the contaminant
material; next, the substrate is extracted and tested by an appropriate
analytical method. Although these tests are referred to by various names,
such as wipe test, swipe test, smear test, leach test, and so on they are
all minor variations on-'a basic test procedure.
Variations for these surface tests include:
o Wiping a predetermined amount of surface area with a solvent laden
swab, gauze, or filter paper. The sample 1s then solvent extracted
prior to analysis. Wiping tests are best used with smooth, non-
porous surfaces such as metal, painted wood, plastic, or glass.
o Samples can be leached from surfaces by placing a filter paper,
or other suitable extraction medium on the surface to be sampled
and wetting the filter paper with a solvent. The filter paper
1s left on the surface until dry, then removed and analyzed in an
appropriate manner. This method works well with rough or porous
surfaces which cannot be wiped (12). -
Another method of surface testing depends on direct visualization of a
reaction in the form of a color change or precipitate formation. With these
tests the type of contamination must be known to choose the correct visual-
ization reagent. Weeks, et.al. (12) described this method of detection for
some cancer suspect primary amines on metal, painted, and concrete surfaces.
The chromogenic spot tests set forth by the authors are sensitive and simple.
To perform these tests, a visualization reagent that will indicate the pre-
sence of the contaminant is applied by brush, pi pet, or spray bottle to a
portion of the surface and allowed to dry. Once the surface dries the
indicator color or precipitate appears on the sampling area if contamination
is present. Limits for detecting the amine contaminants with this technique
were reported as follows:
Stainless Steel - 10 nanograms/cm2
Painted Surfaces - 150 nanograms/cm2
Concrete - 2-5 micrograms/cm2
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These tests, as performed by Weeks et al.(12), have been shown to be very
sensitive; however, the significance of these results in terms of personnel
hazard is not known.
Instrumental Testing
Instrumental testing relies on instruments which provide a qualitative
and quantitative analysis of the type and level of surface contamination.
Instrumental testing for surface contamination can be monitored by ultra-
violet light and by various spectroscopic techniques such as photo-acoustic,
multi-reflection-infrared, and luminescence. The major advantages of instru-
mental testing over surface testing are:
o Instrumental testing is non-destructive (no solvents) to the
test surface.
o Instrumental testing is functional on any chemical species
regardless of its physical state.
One promising tool that uses ultraviolet light analyses for detecting
organic compounds is the portable fluorometric monitor (13) (14). This
tool is in the developmental stage and not commercially available; however,
in pilot tests performed to detect surface contamination on polyaromatic
hydrocarbons (PAH's), the monitor proved to be a valuable asset. It consists
of a hand-held optics unit and a battery-powered electronics console. The
two pieces of equipment are attached by an umbilical cord to an electronics
console and secured to an operator via a shoulder harness. In pilot tests,
the unit has monitored work areas and surfaces at distances of up to three
meters.
The major advantages of this unit are: C
o Operates easily and reliably
o Functions in direct sunlight or indoors in the presence of
strong background illumination
o Provides a quantitative measure concerning the amount of
fluorescent material present
o Discriminates between fluorescence of organic materials and
some inorganic compounds based on their fluorescence lifetimes
o Detects materials spilled or present on a variety of working
surfaces including metals, plastics, and fabrics.
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Molecular luminescence spectroscopy has been shown to be a versatile
and efficient surface detection technique. Both Schuresko (13) and Vo-
Dlnh (14) have used this method to detect various coal and oil shale
wastes. These researchers also feel that the fluorometrlc monitor may be a
reliable technique for monitoring surface contamination by other organic
pollutants.
Testing Procedures
Accurate and reliable contamination sampling can be achieved only if
stringent sample gathering and analysis procedures are implemented and
adhered to during sample testing. A few basic procedures must be followed:
o Secure all necessary sampling tools and containers
o Apply the necessary preservation techniques to maintain sample
integrity during transport and in the laboratory
- o Follow a viable analytical procedure for determining whether or
not the contaminant compound exists.
Obtaining a representative sample is a key factor in assessing contam-
ination of equipment. A well designed sampling procedure that has addressed
all the factors which may bias the sample should be followed. Has the proper
solvent been chosen? Is the extraction medium adequate? Can an instrumental
method be used?
After a sample has been obtained, it must be handled in a manner that
preserves its condition during transportation to the laboratory.. Light and
high temperature, two factors which will degrade many samples before they
can be analyzed, should be avoided.
Prior to analysis, a working analytical procedure needs to be referenced
or developed. Desirable characteristics of qualitative procedures for deter-
mining contamination of equipment surfaces are adaptability for field use,
direct reading, specific sensitivity, and simplicity of operation (15).
Field usable spot tests-have been developed for some primary amines (16). A
book of spot tests that analyzes for functional groups of organic compounds
is also available (17). Most test methods found in this reference can be
adapted for use in a modest field laboratory. There are, however, some chem-
ical compounds which will require analysis by a fully outfitted laboratory.
Equipment Testing
As an illustration of analysis and testing, the Environmental Protection
Agency's mobile incinerator will be considered as an example, with dioxin
contaminated wastes as the incineration material. In order to identify pot-
ential areas of surface contamination the mobile incinerator can be divided
into five distinct components. Selection criteria for each component were
based on the relative location and level of susceptibility to dioxin contam-
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ination. This methodology should be useful in Identifying appropriate levels
of contaminant sampling and cleaning necessary for the mobile Incineration
unit. These five component areas are:
1. The Solids Ram Feed System — The ram section 1n kiln atmosphere Is
made of Inconel 671, and 1s a high priority due to Its relatively
central location. The waste liquid/sludge feed nozzle hydraulic power
units and ram feed unit should be given special attention during
contaminant sampling and decontamination cleanup. A series of "before
and after14 surface contaminant sampling procedures should be Implemented
to ensure that a proper level of cleanliness has been achieved. Preli-
minary tests will indicate the extent of decontamination required and
hot spots. Repeat tests will indicate 1f further decontamination is
necessary.
2. The Rotary Kiln and Secondary Combustion Chamber Duct — This area
ranks relatively low with regard to contaminant sampling and decontam-
inant cleaning. Since the kiln is a self-contained unit, the exterior
surface should remain relatively free from exposure to dioxin-laden
soils or particulates under normal operating conditions. The rotary
kiln is fabricated from carbon steel as a shell and is lined with six
inches of refractory brick. The duct leading to the secondary combus-
tion chamber is made of Inconel 601.
3. The Secondary Combustion Chamber — This component should receive a
moderate level of contaminant sampling and security. Potential hot
spots are the wetted throat Venturi quench and quench elbow sump.
These areas should be kept under constant surveillance for proper
operation. The secondary combustion chamber is also made of carbon
steel and is lined with refractory brick. The wetted throat venturi
and quench elbow are made of Inconel 625. These two parts should be
tested frequently since deposition of hazardous residues is likely due
to the rapid drop in temperature at this point. A series of "before
and after" tests should be performed around the joints and seams to
ensure a safe level of operation.
4. The Ash Handling System - This system warrants moderate contaminant
concern. Potential trouble spots are the sump 1n the base of the con-
tinuous high-efficiency air filter and the fiberglass filter mat.
These components are enclosed in stainless steel and Inconcel 625
housings, respectively.
5. The Pollution Control System - Due to its relative location, this compo-
nent presents very little decontamination concern. A rigorous program
of ultraviolet spot tests and air sampling should be implemented to en-
sure that proper levels of dioxin-laden contaminants have been destroyed
by the incineration process. This system 1s fabricated from Inconel 625
and stainless steel.
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This methodology has been established to provide a quick and easy assessment
of potential trouble spots 1n the mobile Incineration unit. The level and
degree of testing for dloxln contamination should be based on predetermined
safety criteria.
Feed
Off-gases
FEED SYSTEM
KILN
SECONDARY
COMBUSTION
CHAMBER
POLLUTION
CONTROL
ASH SYSTEM
Ash Residues
SUPPORT STRUCTURE
Figure 1. Mobile Incinerator Components
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Analytical Procedures and Techniques
Accurate and dependable dioxin contamination testing can be achieved
by Implementing rigorous testing procedures and following them during testing,
To date, however, methods for analyzing certain compounds have not been
perfected, one of these compounds 1s 2,3,7,8-TCDD. The methods presently
used to analyze dioxin are:
o U.S. EPA Method 8080 to test for chlorinated dibenzo-p-dioxins.
o U.S. EPA Method 8250 to test for the concentrations of semi-
volatlle organic compounds in solid wastes.
o Modified U.S. EPA Region VII, testing protocol for 2,3,7,8-TCDD.
This last method recently has been developed under the U.S. EPA contract
laboratory program, and .is published in Invitation for Bid (IFB) fWA 84A002.
Each method above utilizes some form of solvent extraction followed by
low/high resolution gas chromotography or low/high resolution mass spectro-
metry. The EPA mobile laboratory contains a gas chromatograph/mass spectro-
meter (GC/MS), two gas chromatographs equipped with flame lonization and
Infrared and fluorescent spectrometers.
Sample Analysis
Determining individual isomers of chlorinated dibenzo-p-dioxins in sam-
ples is time consuming and costly. To assure that data are valid, strict
controls must be placed on all samples analyzed. W.B. Crummett et al. (18),
have cited some advanced analytical techniques concerning the detection of
polychlorinated dibenzo-p-dioxins 1n environmental samples. They point out
that a good analytical system must be capable of separating or resolving
each chlorinated dibenzo-p-dioxin from the 74 other possible chlorinated
dioxins. The sampling methods and analytical techniques cited provide an
in-depth look at the level of complexity required to test for dioxin
contamination.
Crummett et al. (18), utilized solvent extraction (benzene via a
Soxhlet apparatus) to remove dioxin-contaminated particulates from field
samples. A benzene extract was passed through a three-column cleanup step
to remove any interferences that may have been present in the sample. Then,
a sample effluent was passed through a flash chromatographic column packed
with alumina. The entire solution was washed with hexane to remove excess
hydrocarbons and chlorobenzenes. Following dilution with a solution of 50
percent methylene chloride to remove chlorinated dioxins and dibenzofurans,
the sample was fractionated. Reversed-phase, high performance, liquid chro-
matography on zorbax and methanol was utilized to remove all chemically
similar species and to separate the chlorinated dioxins by degree of
26
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chlorlnatlon. Gas chromatography mass spectrometry was subsequently em-
ployed to separate and measure the specific Isomers present 1n the sample.
This scenario provides an Illustration of the complexity and level of
effort required to test for dioxln 1n the environment. In general, assessing
contamination levels by sampling the contaminated surface and analyzing the
sample can be a time consuming and difficult process. The objective 1s to
develop a method for sampling and analysis that 1s simple to use in the
field and gives direct, reliable readings. However, surface sampling and
analysis raise many problems which need to be addressed.
The following questions arise: How clean is clean? Are the analytical
or other detection methods able to test down to a health based standard
level? If not, to what surface concentration can the analysis method be sen-
sitive? Is an analysis method available for the type of compound being
tested? Can the analysis method be used in the prevailing situation without
risk of interferences? Sampling of surfaces also poses some difficult ques-
tions. Since there is little information regarding surface sampling pro-
tocols, how can one obtain a representative sample? What methods should be
used to sample rough or'porous materials such as concrete or unpainted wood?
Situations in which sampling and monitoring are required will most
likely be unique, especially regarding sampling method, solvent extraction,
visualization reagent, and analytical protocol.
Solutions to these questions are best discovered by a person who has
had extensive experience in the area of field sampling and/or analytical
methods.
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SECTION 5
DECONTAMINATION METHODS FOR MOBILE RESPONSE EQUIPMENT
INTRODUCTION
Chemical and physical properties of the substances in the water or soil
under treatment are major considerations in designing procedures for decon-
taminating equipment. Decontamination involves removal and detoxification of
the chemical substance. The selection and success of a single method or
sequence of methods is determined by the substance's properties. Procedures
for decontamination methods may be divided into three categories:
o Solubilization methods (use of solvents)
o Chemical degradation of surface contaminants
o Physical decontamination methods.
Each method uses a different mechanism to remove contaminants.
They vary with regard to efficiency, safety, and cost.
The following sections discuss methods that may be employed to decon-
taminate a mobile response system. Both conventional and developmental
state-of-the-art methods are reviewed.
SOLUBILIZATION METHODS (use of solvents)
In employing solubilization methods for the decontamination of the mobile
response equipment, primary consideration must be given to the removal of
contaminated soil particles or oils that have been deposited on the equipment
throughout the cleanup process; these substances may contain an unknown amount
of contaminant. Applying solvent formulations, aqueous or not, typically
involves immersion or spray (flushing) techniques. Spray cleaning techniques
are more suitable to decontamination of the mobile response system. Although
the mechanisms and factors associated with the use of aqueous-based detergents
and organic solvents differ, a typical scenario that outlines major steps in
the decontamination sequence is as follows:
o Rinse the equipment with water to remove gross contamination
o Apply the solvent formulation
o Wait for the formulation to act
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o Rinse the equipment to remove contaminant and/or formulation
o Treat/dispose of process fluids.
The actual sequence of steps will depend upon the solvent formulation
used and the nature of the contaminant. Decontamination procedures that
involve a combination of methods (i.e., use of aqueous and organic solvents)
may require intermediate steps that allow the transition from aqueous to
organic solvents. For example, if the surface to be cleaned is predominantly
organic, an initial water rinse may impede the action of the solvent formu-
lation by forming an aqueous film Impervious to the solvent; it would thus
prevent the TCDD and other organlcs from being dissolved. Final treatment
and disposal of the solvent formulation is necessary as the contaminant has
only been physically removed from the equipment; it still presents potential
problems to the environment. Often the process fluids may be stored for
later disposal by incineration. Another option is to subject the dioxin-
contaminated material to chemical degradation methods; these methods com-
pletely eliminate dioxin and its hazards.
Detergents, Aqueous Surfactants
Adding detergents to water enhances its utility as a cleaning fluid in
a number of ways. Water is effective as a rinse; as a cleaning fluid,
however, it cannot remove hydrophobic contaminants, that is, contaminants
that have no affinity for water. Detergents, specifically the surface-active
agents, enable water or aqueous-based cleaning fluids to overcome this
problem. Surfactants allow the contaminant and the cleaning fluid to
interface, they promote wetting of contaminated surfaces and allow the
cleaning fluid to spread over all surface recesses. Most Important, they
reduce or break the bonds linking the contaminant to the surface. The
cleaning fluid is then able to "lift" the contaminant from the surface and
hold it in liquid suspension. Cleaning is complete following the removal ~
of contaminant and detergent in a rinse cycle.
The detergents Pennwalt 91 and Oakite have been effective in decontam-
inating pesticide barrels used for the storage of 2,4-dichlorophenoxyacetic
acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) or chlordane (19).
The active ingredients of Pennwalt 91 are sodium orthosilicate and caustic
soda. Oakite cleaner is a formulation of alkaline salts, primarily phos-
phates and carbonates, and synthetic surfactants. The detergents in prepared
form were 1 to 2 percent caustic. These products are both alkaline anionic
surfactants which requira an alavated pH to promote saponification of oily
materials. Results show that chlordane removal was 98 percent effective if
the container was rinsed/thrice with water and washed with detergent (20).
Triple rinsing alone as a single step removed at least 90 percent of the
chlordane. Dioxirt, like chlordane, is a chlorinated aromatic. It seems
reasonable to assume that using Pennwalt 91 and Oakite cleaners would give
comparable results for dioxin-contaminated surfaces; however, the selection
of a feasible detergent may require site specific information about the
nature of the contaminant before a suitable product can be selected.
29
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The U.S. Army lists the commercial product, Gunk, as a decontaminant
for equipment and vehicle exteriors (19). Various preparations for Gunk
have been formulated for a number of cleanup problems. These are summarized
in Table 2.
TABLE 2. GUNK DECONTAMINATION PREPARATIONS
FORMULATION
PRIMARY INGREDIENTS
USE
Gunk, I.S. Water >35X
Petroleum distillates <25
Vegetable fatty acid soaps >15
Gunk, V.W. Alkaline salts <85%
Synthetic wetting agents >15
Gunk-, G.P. Petroleum distillates <7W
Water >10
Vegetable fatty acids >9
Gunk, C.D. Caustic soda <70%
Organic chelating agents <35
Industrial shampoo and
rust-retardant
concentrate used for
cleaning metal
machinery
Wash solution for
automobiles and
painted surfaces
Degreaser for use on
garage floors and
power mowers
Corrosion digester for
cleaning tanks
Using one or more of these formulations to successfully decontaminate
the mobile response equipment seems promising. The establishment of optimal
pH and concentration ranges for these or any detergent formulation can only
be beneficial to the effectiveness of a decontamination procedure (21).
A likely candidate for use may be Alconox, a common laboratory detergent
whose primary ingredients are hydrocarbon sulfonates and complex phosphates.
A standard household bleach like Clorox might fit into a decontamination
sequence. Clorox is a 5.25 percent solution of sodium hypochlorite in water,
which may be corrosive to metals. The availability of these two cleaning
fluids is an obvious advantage.
30
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Organic Solvents
Selection of an efficient solvent Is based on Its ability to become
mlsclble with the contaminant, following the general rule of "like-dissolves-
like." In other words, if the hydrogen bonding potential of a contaminant is
identical or similar to that of the solvent, solubilization and removal of
the contaminant will be ensured. As the difference between contaminant and
solvent increases, the effectiveness of the solubilization mechanism becomes
more limited. The use of organic solvents to decontaminate equipment is
especially effective when films or coatings of grease and oil are present.
Care must be taken in selecting organic solvents. They may damage certain
surfaces like plastics, once the contamination layer is removed. Safety and
flammability, along with reactivity of the solvent with the contaminant, are
factors that should be considered.
Organic solvents in liquid form may .have, limited use in an incinerator
decontamination process. Unless they are extremely viscous, liquids tend to
run off vertical surfaces before they completely penetrate the contaminant.
Gels, foams, or pastes which have the ability to cover, adhere to, and dissolve
a contaminant-layer deposited on a surface show promise as acceptable solutions
to this problem. These foams weaken or destroy the link"between contaminant
and surface, and also produce lower volumes of waste (11). Foams are usually
generated from acid and air, nitrogen or inert gas. Various chemical add-
itives such as inhibitors, foam stabilizers, and surfactants are added. Gels
may be either organic-; or inorganic-based systems containing decontaminating
chemicals such as acids. Problems may arise if the decontaminating chemicals
inhibit generation and maintenance of a gel medium. Pastes usually consist ot
a filler, a carrier, and acids combined to give an appropriate consistency.
Application methods vary among the three. Foams can be pumped throuyh
pipes or sprayed on external surfaces. Gels are generally applied to external
surfaces. Internal surfaces of removable parts can be cleaned by dipping,
them into the gel. Pastes are currently used on external surfaces and applied
by hand; however, spraying techniques may be possible if the appropriate
paste consistency is formulated. Of the three techniques, only use of foams
produces low worker exposure.
Foams can be applied internally by pumping and externally by remote
spraying. Applications of gels and pastes are done manually and expose the
worker to their ingredients. Neither gels nor pastes have been sufficiently
studied to properly evaluate them technically or economically, but they
appear promising. Foams have been tried on a larger scale and found to be a
simple operation generating minimal quantities of waste while usiny simple
equipment.
The removal of contaminant and solvent, may be achieved using a rinse
cycle. Foams are often removed by wet vacuuming followed by water rinsing
with reasonably small volumes of water. Collection of all wash and rinse
solutions is necessary if the contaminant is not chemically altered to a non-
hazardous form. If the solvent selected is volatile, a temporary structure
31
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to house the decontamination procedure should be built to prevent the vapor-
ized solvent from spreading to other sites. The enclosure design should
include proper ventilation to eliminate risk to personnel. Upon completion
of the equipment decontamination, the structure itself should be disposed of
by appropriate means, such as incineration.
In the following discussions, consideration is primarily given to cold
•cleaning solvent application. Cold cleaning implies that the solvents are
used at ambient temperatures. They may be sponged or sprayed onto the con-
taminated surface. Following application, the solvent sets on the surface
for a period of time and is subsequently removed in a rinse cycle or by
evaporation. Vapor degreasing, an alternative cleaning method that depends
on solvents, does not appear to be an operation readily adaptable to large-
scale cleaning needs. It uses vapors from a heated solvent for cleaning and
usually requires that the contaminated item be placed inside a tank for
treatment.
There is a number pf liquid organic solvents commonly used to degrease
industrial equipment. These solvents effectively remove dirt and oil layers
that have been deposited on equipment surfaces. Three standard solvents used
are trichloroethylene, 1,1,1-trichloroethane, and perchloroethylene. Tri-
chloroethylene and 1,1,1-trichloroethane are the major solvents used in vapor
degreasing and cold cleaning operations, respectively (22). Vaporization of
the solvent is a factor to consider, especially when using trichloroethylene
(b.p. 57°C). It may be necessary to temporarily enclose the decontamination
procedure to contain these solvent vapors.
Studies on decontamination by the Bendix Corporation in Kansas City,
Missouri, identified several liquid organic solvents that removed grease from
surfaces (23). The surfaces were subjected to a solvent rinse before analysis.
Three solvents representative of a moderate hydrogen-bonding class were shown
to remove a limited amount of contamination. It is believed, however, that
improvement of contamination removal is possible if the surfaces are allowed
to remain in contact with the solvent for a longer period of time, or if
multiple rinses are performed. The solvents used were 1,1,2-trichloroethane,
2-ethyl-hexyl acetate, and acetone. Heptane, a non-hydrogen-bonding solvent,
also removed a limited amount of contaminant after one solvent rinse.
Decontaminants used by the U.S. Army for removing chemical and/or biolog-
ical agents from vehicle exteriors and equipment include a number of organic
solvents that might be useful in decontaminating the mobile response equipment
(19). Alcohol, diesel fuel, and naphtha are among those. Specific organic
solvents included: BPL (beta-propiolactone), carbon tetrachloride, formalin-
methanol, monoethanolamine (10 percent aqueous solution), and perchloro-
etnylene. In addition, a solvent solution of hexachloromelamine (8 percent)
in 1,2-dichloroethane may have potential use.
Formulation of a hydrogen-solvent-based dispersant/gelling agent mixture
has been achieved for the cleanup of structures contaminated by oil spills
(24). The dispersant and gelling agent are mixed in storage drums in a volume
ratio of 4 to 1. The gelling agent selected, Triton X-100, was evaluated
32
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according to efficiency and nature of toxicity. Approximately 30 dispersants
have been approved for use with this yelliny agent by the Warren Spring
.Laboratory, Stevenage (England); these are licensed by Britain's Ministry of
Agriculture, Fisheries, and Food. The gel is produced in and delivered to the
contaminated surface using a spray gun* The spray gun is designed to mix two
independent feed trains prior to delivery as one stream from a flat jet
nozzle. The gel is applied as a thin film over the contaminated surface and
allowed to set. The gel mixture itself is stable for about 24 hours; however,
stability may be lost after a shorter time defending on temperature conditions.
After a sufficient amount of time, the surface may be rinsed off. The wash
solution must be collected and disposed of by appropriate methods. Decon-
tamination should be complete after a single treatment, but excessive con-
tamination may require a second application.
Health Physics, Inc., a subsidiary of Quadrex, has developed a copolymer
that shows potential for use in the decontamination of equipment surfaces.
The copolymer, Quadcoat, is sprayed onto a contaminated surface where it
reacts with the particles or residues present. The polymer dries, loses its
adhesive character, and .shrinks. It and the absorbed contaminant are then
removed by hosing down the equipment. The polymer has a notable advantage
over liquid solvents because it could be applied to vertical as well as hori-
zontal surfaces. The effectiveness of Quadcoat as a decontaminant is depen-
dent on its contact with the unwanted materials.
When selecting a solvent it is also important to select a "sate" solvent.
It is not good practice to use a.solvent that may be almost as hazardous as
the contaminant itself. A safe solvent, such as 1,1,1-trichloroethane, should
have a high flashpoint (or no flash point), a low evaporation rate, and a
high threshold limit value (TLV). Solvents sucn as carbon tetrachloride (low
TLV), acetone (low flash point), or formalin (suspected carcinogen) are not
good choices since the risks to the workers may be hign (EPA Peer Review,
1985).
Steam Cleaning
High-pressure steam cleaning methods are often effective in removing
surface contamination (11). The production of large volumes of wastewater
such as those generated by flushing methods is avoided; often the method is
simply an easier or quicker procedure. The pressure of the steam as it is
delivered to a contaminated surface is the primary mechanism for successful
removal. Detergents or chemicals may be added to facilitate removal of
contaminants that tightly adhere to equipment surfaces. The chosen additives
are mixed with steam and entrained to form a sinyle stream that is discharged
onto the contaminated surface. Although the steam is delivered under hiyh
pressure, the low density of the cleaning fluid demands that the steam nozzle
be positioned within a few centimeters of the contaminated surface. Supplied
pressures for steam are typically 6.1 to 6.8 atm; discharge of the steam
through the equipment and out the nozzle usually results in a Ib percent
reduction of the supply pressure. Rates tor the discharge of detergents are
33
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approximately 200-300 1/hr.
The equipment is commercially available and has been used in various
applications (11). It is also a fairly low-cost method. Its effectiveness
depends on the specific application. The spread of contamination is perhaps
the primary factor to consider, especially where the removal of hazardous
substances is concerned; the impingement of the steam jet can redistribute
the contaminant. Containing the cleaning procedure in a temporary structure
has been suggested as a feasible solution to this problem. Following the re-
moval of the decontaminant from the equipment, the enclosure must be thoroughly
cleaned. Care must also be taken while using steam cleaning equipment. For
obvious reasons, the temperature and pressure conditions of the steam can be
hazardous to personnel. In addition, visibility may be limited if condensing
steam produces fog during the cleaning operation. It is recommended that
respiratory, eye, and skin protection as well as thermally insulated gloves
be used during the procedure.
This type of treatment is not recommended where the contaminants may
volatilize, creating a hazardous condition for the workers and the surrounding
environment. Using a water blaster (hydrolaser) to physically clean the
surface by applying water pressure to the contaminated equipment is a better
technique in this situation.
Chemicals (High/Low Concentration)
Many chemicals are acceptable for decontaminating exterior locations
(such as concrete and metal) and interior structural members (such as painted
surfaces or concrete). "Decontamination" as defined in the context of these
chemical processes is removal of superficial dirt and oxides from surfaces.
Most of these chemical methods seem applicable for dioxin decontamination of
the mobile response equipment because dioxin accumulates on the equipment's
surface (25). Some chemical methods are highly corrosive to the surface.
Acids and alkalis are used to dissolve metal from the surface; complexing ;
agents are used to enhance the dissolution. Significant corrosion is normally
acceptable for equipment that is decommissioning; this is not desirable for
mobile response equipment.
Generally, solutions with greater than 2,000 ppm (0.2 percent) of reagent
are classified "high concentration." "Low concentration" solutions contain
less than 0.2 percent reagent and normally less than 0.1 percent. Some
complexing agents are also discussed in this section. The solubility of the
metal from the surface being cleaned increases due to the formation of the
complexes, which enhances their removal from scales, deposits, or corrosion
films. For example, triethylenetetramine hexaacetic acid (TTHA) and hydroxy-
ethylenediamine triacetic acid (HEDTA) complex with heavy metal ions such as
cobalt, nickel, iron, chromium, and many other di- and trivalent ions. Citric
acid, citrate, oxalic acid, oxalate, ethylenediamine tetracetic acid (EDTA),
and phenylthiourea components of the decontamination reagents described below
can all form metal ion complexes. Although these complexing agents are not
effective in complexing most organic compounds, they-can be valuable in
removing a thin-layer surface metal and/or metal oxide, thereby releasing the
34
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contaminants (e.g., dloxln) deposited on the surface of the mobile response
equipment.
Many chemical decontamination processes used to decontaminate metal
surfaces in nuclear power facilities are listed below (25). The process for
Inconel and carbon steel are listed first because the solids ram feed system,
ash chute, and kiln-secondary combustion chamber (SCC) duct are made of
Inconel, and the rotary kiln and the SCC are made of carbon steel.
Reagents for Inconel Decontamination
High Concentration Reagents-
o Conditioning with alkaline permanganate (AP) at 90°C to oxidize
the corrosion product film. After water rinsing, treatment with
0.4M ammonium citrate (AC). AP is 2.5M NaOH + 0.2M KMnO-4.
o Treatment with AP as in above followed by oxalic acid.
o Treatment with--AP and oxalic acid as above followed by treatment
with AC. AC prevents redeposition of bxalate precipitates.
o Conditioning with AP as above followed by treatment with citrox
(0.2M citric acid + 0.3M oxalic acid). Citrox neutralizes any
traces of the alkaline solution, dissolves any manganese dioxide
residue, and complexes the iron oxides to keep them dissolved and
prevent redeposition.
Low Concentration Reagents-
o Treatment with chelating agents such as EDTA, citric acid, or
oxalic acid.
o Treatment with hydrogen peroxide in low ppm concentration
range at temperatures less that 70°C. This process does not
solubilize iron.
o Treatment with a mixture of oxalic acid (2-3 g/1) and hydrogen
peroxide (50 g/1) at 80°C. Also effective for decontamination
of carbon steel.
Reagents for Carbon Steel Decontamination
o Treatment with HCl-containing inhibitors like propynol form-
aldehyde. Typical suggested concentrations for HC1 and inhibitor
are 15 percent and 1 percent by volume, respectively.
o Treatment with 0.4M ammonium oxalate and 0.16M citric acid and
0.3M H2(>2 at 90-95°C. Citric acid complexes the iron ions and
prevents formation of insoluble oxalate.
-• - 35 ... __.
-------
o Treatment with 0.5 percent solution of EDTA, citric acid, and
hydrazine at pH 6-8 and temperature 90-100°C.
o Treatment with inhibited AC or sodium bisulfate.
o Treatment with inhibited 9 percent sulfamic acid (NHgSOsH).
Typical Inhibitors are 5 percent solution of formaldehyde or
propynol .
o Treatment with 0.3M H2S04, 0.1M oxalic acid, and phenylthiourea
(sulfox) at 25°C for 40 minutes.
o Treatment with phosphoric acid (90-130 g/1) at 85°C for less
than 20 minutes. Redeposition occurs if acid is left in contact
with base metal for more than 20 minutes. The process 1s mildly
corrosive.
o Treatment with "new solvent" NS-1 (a proprietary product of Dow
Chemical Company).
o a) Water rinse
b) Scrub with 10 percent citric acid and 5 percent detergent
c) Scrub with 0.3M citric acid, 0.1 percent detergent, and 0.5M
HC1 rinse
d) Scrub with 6M
e) Repeat d) as necessary.
•
o Treatment with 0.002M HEDTA, 0.002M citric acid, and 0.002M
ascorbic acid at- pH 2.6.
o Treatment with 0.002M HEDTA, 0.002M citric acid, plus 0.004M
hydrazine at pH 3.3.
o Treatment with 0.002M HEDTA, 0.002M citric acid, plus 0.012M
hydrazine at pH 7.
Reagents for Oil and Grease Removal
o Treatment with 1 wt. % Lissapol. (nonionic wetting agent),
1.2 wt. % sodium carbonate, 2 wt. % sodium tripolyphosphate,
0.1 wt. % sodium carboxymethyl cellulose, plus 0.5 wt. % EDTA at
pH 9.5.
o Treatment with 1.5 wt. % Comprox (anionic wetting agent),
2.5 wt. % sodium sulfate, 0.6 wt. % sodium carbonate, 2 wt. %
citric acid, 1 wt. X EDTA at pH 3 and temperature of 70°-80QC.
This solution attacks metal.
36
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For a number of other processes listed by Nelson and Divine (2b), the
long periods (many hours to days) of chemical application are specifically
mentioned. Because applying those methods to the surface of the mobile
response equipment is difficult in practice, they are not listed here. The
application time for the methods listed here is not specifically mentioned
in the literature (25). The high concentration chemicals probably require
short chemical application periods to decontaminate the surface of the
mobile response equipment. Maintaining high temperature for short periods
would be practical. Dilute solution processes, which are effective only when
applied for long duration, have limited use for decontaminating the mobile
response equipment.
The reagents presented in this section vary in their rate of attack on
metal surfaces. Deciding which reagent to use for a particular purpose will
depend on the metal being cleaned and its degree and nature of contamination.
The availability of the ingredients, their cost, and their handling hazards
must also be considered. The wide variety of reagents facilitates choosing
one suitable for the specific application.
Summary of Solubilization Methods
Decontamination methods that utilize Solubilization techniques are very
effective in removing surface contaminants (See Table 3); however, they are
limited in detoxifying hazardous chemicals unless the cleaning fluid or
operating conditions (i.e., high temperatures) specifically degrade the
chemical. Using detergents in cleaning procedures is common and relatively
simple, and it presents minimal safety problems to personnel.
•
Various detergent formulations are available for removing dirt or oil
layers, the typical mediums containing contaminants. Cleaning procedures'
that use organic solvents have a number of limitations. The solvents may be
toxic when inhaled, easily volatile, and/or flammable. They may also damage
certain nonmetal surfaces such as plastic-coated pieces. The development of
gels, pastes, and foams reduces some of these problems which are especially
associated with liquid organic solvents. A semi-solid form such as a gel
formulation shows potential if an appropriate (effective) formulation is
available. High-pressure steam cleaning does not demonstrate applicability
to the mobile response systems because the dangers associated with the spread-
ing of contaminants are too great.
CHEMICAL DEGRADATION OF SURFACE CONTAMINANTS
Deyrading a contaminant to a less hazardous substance greatly reduces the
spread of contamination inherent in the removal of the contaminant from the
equipment. This essentially eliminates the problems associated with the
generation of contaminated wash solutions. At present, the majority of
degradation techniques require contaminant removal from a surface followed by
treatment in a reactor or laboratory setup. Chemical degradation, in this
regard, is the final step in the decontamination process.
37
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TABLE 3. SUMMARY OF SOLUBILIZATION METHODS FOR
REMOVAL OF SURFACE CONTAMINATION
REMOVAL
OF BASE METAL
AREA OF
APPLICATION
QUANTITY OF
WASTE PRODUCED
WORKER
EXPOSURE
OVERALL COSTS
COMMENTS
FOAMS, GELS,
AND PASTES
None-Slight
Internal/
External
Small
Foam: low Gels
& Pastes:
Moderate
Moderate-High
Gels and pastes
cannot be easily
applied to the in-
side of small
diameter pipes
DETERGENTS, AQUEOUS
SURFACTANTS
None
Internal/
External
Large
Moderate
Moderate
Formulations may be
tailored to specific
contaminants
ORGANIC
SOLVENTS
None-Slight
Internal/
External
Moderate
Moderate
Moderate-
High
May be flam-
mable, and/or
damage non-
metal sur-
faces.
Limited
effectiveness
on vertical
surfaces
38
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Destruction of dloxin has, In general, been a large problem because of
its persistence in the environment and its apparent unreactive nature.
Recent laboratory and field work show that dioxin and similarly-structured
chlorinated aromatics such as PCBs and DOT may be amenable to chemical
degradation. Degradation's primary object is to convert the toxic compound
to a less hazardous form or to a compound which exhibits a yreater degree of
solubilization in, for example, a solvent employed in the decontamination
procedure. Ideally, the degradation step should be incorporated in the
pretreatment routine.
The following sections review and discuss the various chemical degrada-
tion methods available (See Table 4). Emphasis will be placed on those
methods that show promise for in-situ decontamination operations.
Oxidation
Oxidation, as with-most of the chemical deyradation methods, is a single
step in the general decontamination process. Its role in the pretreatment or
final detoxification staye depends on the product to be obtained and the
method to use.
Tetrachlorodibenzodioxin (TCDD) in carbon tetrachloride has been oxidized
by ruthenium tetroxide in laboratory operations (26). An excess quantity of
the oxidant is supplied to limit the number of reaction intermediates. The
reaction efficiently utilizes ruthenium tetroxide. Following the completion
of an oxidation step, a secondary oxidant is formed. The presence of the
secondary oxidant lessens the demand the reaction intermediates place on the
primary oxidant.
The reaction follows first-order kinetics with a reported half-life ot
TCDD of 560 minutes (20°C). It is advisable to proceed usiny a continuous
reflux of carbon tetrachloride; this reduces the half-life of TCDD and thus
speeds up the oxidation process. In addition, the rate may be increased by
raising the temperature during the reaction. Specifically, a temperature in-
crease to 7U°C results in a half-life of 15 minutes (27). Ruthenium tetroxide
is a powerful oxidizing agent and must be used with solvents of electronegative
character. Oxidative control of TCDD degradation has been limited to labora-
tory work. Studies on a larger scale should define the operating conditions
and lend evidence to the feasiblity of extending this technique as an in-situ
method.
Hydrodechlor1 nation
Hydrodechlorination is a means ot decontamination that appears to readily
adapt to PCB, DDT, and dioxin contamination problems. The nickel-catalyzed
reaction is carried out in ethanol; sodium hydroxide is present and functions
as an acid-acceptor. As the reaction proceeds, aromatic chlorine atoms are
removed one by one, thereby reducing the hazardous potential of the chlorinated
compound to an environmentally acceptable product. Laboratory-scale hydro-
39
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STABLE 4. SUMMARY OF CHEMICAL DEGRADATION METHODS
FOR REMOVAL OF SURFACE CONTAMINATION
REMOVAL OF
BASE METAL
AREA OF
APPLICATION
QUANTITY OF
OF WASTE PRODUCED
WORKER
EXPOSURE
OVERALL
COSTS
COMMENTS
HIGH INTENSITY
LIGHT
None
External
Small
Low
Low-Moderate
Most effective
on flat sur-
faces
UV LIGHT
CLEANING
None
External
Small
Low
Low-Moderate
Gross con-
tamination
must be re-
moved first
for UV to be
effective
ELECTRO
POLISHING
Can be carefully
controlled
External/
Internal
Moderate
Moderate
Moderate-High
Contaminated
object must be
immersed in a
liquid bath
40
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chlorinatlon of PCB and DDT shows successful conversion of the parent poly-
chlorinated compounds to molecules that contain at most one chlorine atom (28),
The Sun Ohio Process which follows this reduction principle has been used for
several years to remove chloride ions from dielectric fluids containing PCBs.
The endproducts are sodium chloride and trichlorobenzene (EPA Peer Review,
1985).
Although studies have been limited to laboratory reactions for dioxins,
hydrodechlorination shows potential for development as an in situ operation.
The solvent could be applied to the contaminated surface, allowed to degrade
the dioxin present, and then be removed in a rinse cycle.
Application of the procedure to dioxin deserves some investigation.
Photochemical Reduction
Photochemical reduction shows adaptability as a decontamination method
for in situ operations. Three conditions must be met for photochemical
reduction: 1) the compound must be able to absorb light; 2) light must be
supplied at the proper wavelength and intensity; 3) and a hydrogen donor must
be present (29.) The hydrogen donor, present as a solvent, could be applied
directly to the contaminated surface of the mobile response equipment. A
suitable solvent should be relatively nonvolatile and nontoxic. Expense and
availability are other concerns. Once applied, the solvent would interact
with the contaminant in the presence of UV light. The final step in the
sequence would be the removal of the solvent from the equipment in a rinse
cycle.
Various studies support the idea of photochemical degradation of dioxin.
Field experiments using a 2,4-0/2,4,5-T ester formulation (.02 ppm TCDD)
resulted in a 50 percent decrease of TCDD after one day; TCDD was undetectable
after the second day (29).' In Seveso, Italy, the application of an olive oil
solution to small plots of TCDD-contaminated grassland effectively destroyed
90 percent of TCDD after nine days in sunlight. Laboratory studies show a 50
percent reduction after six hours. These studies involved the irradiation of
thin films of TCDD placed on glass plates (30).
Although an in-situ operation is the ideal, removing and subsequently
treating dioxin-contaminated rinses is an acceptable alternative (31). Circu-
lation of these rinses through a UV-irradiated tank would be relatively simple.
High pressure water cleaning used in conjunction with photochemical reduction
ideas may be an acceptable method. However, soil particles or oil may inter-
fere with the absorption of light by TCDD. This could be a significant
problem that should be considered in developing the decontamination procedure.
Another inherent problem is the availability of sunlight. Obviously,
sunlight is limited during certain seasons of the year. Using commercial UV
lamps may be an alternative. Selection of a commercial light source, if
necessary, will most likely be dependent on effectiveness (i.e., wavelength
range), safety (i.e., voltage requirement), and cost. '
41
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Flash Cleaning
Flashlamp cleaning systems developed by Maxwell Laboratories, Inc., have
been employed to clean and remove surface coatings on Industrial equipment
(32). The system 1s acceptable to the environment, shows versatility 1n
removing a variety of substances or materials, and performs localized cleaning
only. In addition, flash cleaning systems can selectively remove one or more
surface layers. Methods of cleaning using flashlamp systems are comparable
to those using laser radiation with one exception: cost; flashlamp systems
are much less expensive.
Maxwell Laboratories, Inc., has developed a high-Intensity light source
(lamp) using xenon gas-filled tubes that are able to deliver short pulses.
These lamps are marketed under the trade name "Flashblast." Decontamination
is affected by placing the lamp on the contaminated surface and initiating
the firing or blasting sequence., The emitted radiation extends from the ultra-
violet to the beginning of the infrared; more than half is emitted in the UV.
Flash cleaning 1s limited because it needs a relatively flat surface to be
effective. Removal depends on the contaminant and the treatment conditions.
The contaminant may be photochemically reduced, vaporized, incinerated, or in
the presence of water, "steam cleaned." Future studies may define more com-
pletely the mechanism specific to the contaminant.
The lamp can be hand-operated or controlled from a distance. Flashblast
units are available in various sizes (33). The smallest moves easily and
operates from a standard outlet (120 volts). If performed correctly, the pro-
cedure is not dangerous to the operator, although ear protection that guards
against the loud noises produced by the system 1s highly recommended. Flash
cleaning has been used to remove epoxy paints from equipment and to clean
corroded steel surfaces (32). This latter process is aided by an application
of, 6 percent citric acid solution to the metal surface prior to irradiation.
A second flash cleaning technique, the pulsed ultraviolet (PUV) radiation
system, is in the developmental stage. It also shows promise as a means to
decontaminate the mobile response equipment. The system utilizes ultraviolet
energy to chemically degrade the contaminant. The light source is more
intense and richer in UV than in the xenon lamp systems. The mechanism for
detoxification appears to involve pyrolysis, incineration, and/or photo-
chemical reduction of the molecule. The radiation is delivered to the surface
by high-intensity industrial PUV lamps. The surface temperature is rapidly
raised to 2,760°C and the contaminant is destroyed.
Delivering the energy in short pulses minimizes damage to the surface;
the rapid flash heating essentially eliminates vaporization of the contami-
nant. Higher intensities can be used to remove equipment coatings that have
been contaminated by absorption. Although testing is not complete, PUV light
has been effective in reducing the pesticide, malathion, to traces undetect-
able by GC/MS techniques.
42
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Electropolishing
Electropolishing is a relatively simple process. Except for equipment
for circulating or agitating the electrolyte, the systems have no moving parts
and are amenable to remote operation and mechanization to minimize personnel
exposure. The smooth surfaces produced by electropolishing are reportedly
much easier to clean using standard decontamination techniques than are metal
surfaces with a normal as-received finish.
The metal to be decontaminated is utilized as the anode in an electro-
lytic cell. The passage of electric current through the electropolishiny
system results in the dissolution and, under proper operating conditions,
the progressive smoothing of the anode's surface. Contamination present on
the metal surface and entrapped within surface imperfections is transferred
to the electrolyte by the process. The amount of metal removed from the
component surface is controlled by the duration of application, usually,
less than O.OU2 inches to affect decontamination. The surface metal is
reportedly uniformly removed with no preferential attack of grain boundaries
or other microstructural features.
After electropolishing, the metal should be rinsed with water, dried,
and then painted. Phosphotizing the surface enables the paint to adhere
better. If left uncoated, the highly active metal surface will corrode or
oxidize, or the fine interstices will fill with physical contamination (EPA
Peer Review, 1985). Studies have found the electropolished surfaces have
better corrosion resistance than the original surface.
Because of its inherent stability, safety, and applicability to a
number of alloy systems, phosphoric acid is generally used as the electrolyte.
Due to its hygroscopic nature, phosphoric acid helps minimize airborne
contamination. It is believed that the good complexing characteristics of
phosphoric acid for metal ions is a significant factor in minimizing recon-
tamination from the electrolyte. Other acids and chemicals have been added
to the pnosphoric acid electrolyte to enhance surface passivity, increase
brightness, or promote sludging.
Summary of Chemical Degradation of Surface Contaminants
Most chemical degradation techniques show limited usefulness when they
are extended to'mobile response decontamination procedures (see Table 3),
primarily because of the contaminants unreactive nature. The development
of an in-situ operation using the mechanistic approach of oxidation or
hydrodechlorination does not seem effective or cost-efficient. Photochemical
reduction, also a developmental idea, shows promise as a simple, low-cost,
effective operation. Its consideration seems unlikely at the present time,
however, because the procedure has only been studied under laboratory
conditions.
>
Flash cleaning is an innovative procedure primarily used for specialized
cleaning operations. Its extension to the decontamination of the mobile
43
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response equipment shows promise; the procedure is not dangerous, permits
detoxification as well as removal, and exhibits selective and controlled
removal of surface layers. A prime factor is the high degree of assurance
that the contaminant has been effectively removed.
PHYSICAL DECONTAMINATION TECHNIQUES
A number of commercially available physical decontamination techniques
have been identified and evaluated as to their potential for effective use.
Ideally, the cleaning of any surface should meet the following criteria:
o Minimal exposure of personnel to the contaminants
o Minimal volume of secondary waste generated
o Minimal recontamination of previously cleaned surfaces
o Minimal off-site release
o Minimal manpower costs.
Selection of appropriate cleaning processes must also take into account
the required degree of cleanliness, as well as the chemical and physical
properties of the contaminant which determine the strength of adherence to
the substrate. The physical decontamination techniques evaluated can be
grouped into one of two categories: abrasive methods and non-abrasive methods.
ABRASIVE CLEANING METHODS
Abrasive cleaning methods are physical decontamination techniques which
work by rubbing and wearing away the top layer of the surface containing;the
contaminant. The methods are generally very effective at removing the contam-
inant from the surface. The following sections review the- abrasive cleaning
methods available (see Table 5).
Mechanical Methods
Mechanical methods include using cleaning devices like brushes for
cleaning the insides of pipes. The brushes may be composed of metal or nylon
and are commonly blown through the pipe with water or air, or pushed throuyfi
manually. The amount and .type of contaminants removed will vary with hardness
of the bristles, length of time of brushing, and the degree of brush contact
with the pipe surface. Pipes with inside diameters up to four inches can be
cleaned with brushes.
Another type of pipe cleaner is a bullet-shaped object known as a pig,
which is forced through a pipe by fluid pressure (11). The pig is capable of
scraping and abrading tightly held material off the w.all of the pipe. Pigs
44
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TABLE 5. SUMMARY OF ABRASIVE METHODS FOR REMOVAL OF
SURFACE CONTAMINATION
REMOVAL OF
BASE METAL
AREA OF
APPLICATION
QUANTITY OF
WASTE PRODUCED
WORKER
EXPOSURE
OVERALL
COST
COMMENTS
MECHANICAL
METHODS
(pigs)
Slight
Internal
Moderate
Low
Low
Flexible and
compressible
Cleans-small
diameter
pipes.
MECHANICAL
METHODS
(brushes)
Negligible
Internal/
External
Moderate
Moderate
Low
Wide range
of brush
sizes and
bristle
stiffness.
ABRASIVE
CLEANING
(wet)
Can be
carefully
contained
Internal/
External
Large
Moderate
Moderate
Removes
tightly
adhering
material'.
No air
pollution.
ABRASIVE
CLEANING
(dry)
Capable of
severe
abrasion
Internal/
External
Large
High
Moderate
Dust may be
explosive.
DRY ICE
BLASTING
Negligible
External
Small
Moderate
Moderate
Useful for
removing
smearable
contam-
inants.
45
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are available with soft cores and tough, abrasive outer coatings. They are
normally available for cleaning pipes with diameters from 2 to 150 cm., but
can be obtained in diameters as small as 1 cm. The plastic-bodied pig is
flexible enough to pass through 90° elbows and compressible enough to pass
through reductions of 1 cm. in pipe size.
The equipment to perform these types of mechanical cleaning is readily
available in a wide range of sizes. Brushes and pigs are relatively inexpen-
sive and easy to use; further, they generate small amounts of waste material.
They do, however, require physical access to both ends of the pipe being
cleaned.
Air Blasting
Air blast equipment uses compressed air to force abrasive material
through a nozzle at high velocities. The cleaning efficiency of this method
is a function of a number of factors including: distance between the nozzle
and the surface being cleaned; air pressure; length of time of application;
and the angle at which the abrasive strikes the surface. The distance between
the nozzle and the surface is important because the velocity of the abrasive
particles decreases with distance traveled. The abrasive stream also diverges
with distance traveled, resulting in weakened cleaning action. Air pres-
sures used vary with the material being cleaned. Softer metals are cleaned
with air pressures ranging from .7 to 4 atm while steel and concrete are
cleaned at pressures of 5 to 6 atm (11).
Abrasive contact time is very important. If it is too short, the cleaning
will be insufficient; if it is too long, excessive base metal may be lost,
even to the point of wearing a hole through the-object being cleaned. Gener-
ally, the abrasive stream should hit the surface steadily for not more than a
few seconds. Tests should, be conducted to determine the optimum cleaning
time for each particular situation. Finally, if the angle at which the
abrasive strikes the surface is too low, the resultant cleaning action will
be insufficient. This can be a problem when trying to clean the inside of
pipes or other objects.
Pipe lengths of up to 30 meters can be cleaned using flexible hose, which
is capable of moving through one or more elbows (11). A nozzle can also be
attached to the end of a gun and used to clean inside tanks. In addition,
air blast cleaning has proven effective over years of use, especially in
removing tightly-adhered material, and equipment for it is commercially
available.
The system's disadvantages are its inability to closely control the
amount of material removed and the large amount of waste that it generates.
The contaminated dust can migrate from the work area and provide risk to the
worker and the environment. Dry methods also create sufficient quantities of
abrasive dust to require a collection and filtering system to clean the air.
The most serious limitation is the uncontrolled toxic dust generated from
blasting a dioxin-contaminated surface.
46
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Wet Blasting
Wet blast cleaning, uses very fine abrasives ranging 1n size from 100 to
5,000 mesh, which 1s much smaller than that used for air blast cleaning (11).
By using very fine abrasives, the amount of materials removed can be carefully
controlled and the surface smoothness and dimensions of precise equipment
maintained. Water Is used at pressures as high as 300 to 600 atm. The
combined effects of both the water and the abrasive produces a stronger
cleaning action than can be obtained with water or dry abrasives alone (11).
Wet sand abrasive cleaning costs $25-$35 per m2 (Norman Hlggins, Eastern
Cleaning Equipment, personal communication, 1984).
The abrasive Is suspended 1n water by an agitator. Compressed air and
nozzles, as In air blasting, deliver the abrasive/water mixture to the decon-
tamination area. The nozzle's lifetime may need to be considered; the abrasive
action of water-driven particles is more severe than that of air-driven
particles, therefore the nozzle wears out faster (11). Careless application
may produce excessive wear of metal surfaces, so careful control 1s necessary.
Water abrasive blasting is more effective in cleaning recesses and
produces a smaller amount of waste then air abrasive cleaning. It will
remove tightly-adhered material and corrosion layers and produces less dust
than dry blasting methods. Destruction of the abrasive forms fine sand
particles, which must be cleaned off surfaces by rinsing or vacuuming.
Another variation of wet abrasive cleaning is air slurry blasting. As
much as 30 percent (by volume) of abrasive is mixed with water to form a
slurry, which is propelled by 6 atm of air. The rate of flow 1s adjustable,
which in turn adjusts the cleaning action. Different cleaning effects can
also be obtained by changing the type and size of the abrasive. Testing to
determine the optimum slurry composition is required.
Slurry cleaning can also be adapted to clean the interior of a piping
system. This method would be particularly useful for cleaning small diameter
pipes (15 centimeters and under) and associated valves and fittings (11). Ad-
ditional equipment would be required to recirculate and pump the slurry, and
a reservoir of extra slurry would be necessary (11). As with any abrasive
blasting operation, residual dust or abrasive particles may adhere to metal
surfaces and should be removed by flushing the piping system.
Abrasive Materials
The different abrasives can be grouped into the following three general
classes based on hardness of the abrasive material: soft, intermediate,
and hard.
Soft abrasives include wheat grains, corn cobs, crushed nut hulls
(such as walnut or hickory), rice hulls, and fruit pits (36). Soft abrasive
cleaning removes only loosely held, smearable contamination without marring
the surface. Air alone propels the abrasive. Because considerable amounts
of dust or powder are produced, soft abrasives are not""highly recommended
for removing toxic contaminants unless the operation is enclosed.
47
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Intermediate abrasives are harder than soft material, yet the cleaning
action 1s gentler than that obtained with hard abrasives. The principal
material In this category 1s manufactured glass beads (11). They can be used
to clean precision parts. Although they produce less dust, they are still
breakable, so their longevity Is limited. Glass beads are more expensive
than naturally occurring mineral abrasives and probably aren't much more
desirable than other types of abrasives.
Hard abrasive materials are harder than the material being removed.
They may be subdivided into naturally occurring minerals, synthetic minerals,
and metal pellets. Natural abrasives consist of materials such as sand,
crushed rock, garnet, pumice and emery (36). By far, sand and crushed rock
are used in the largest quantities; use of the latter three is limited. When
used in high-velocity blasting operations, garnet, pumice and emery disinte-
grate rapidly, withstanding only a few passes. Large amounts of dust are
produced when these materials are used in air blasting; when used with water,
the fine particles cause a cleanup problem.
Synthetic mineral abrasives Include silicon carbide and aluminum oxide,
which are man-made in electric furnaces (36). These abrasives are more
resistant to breakdown than sand, but less resistant than metallic shot.
Their, use is limited because the initial cost is higher than most naturally
occurring minerals.
Metallic abrasives have the highest initial cost of those abrasives
•discussed. They are available in two general types: grit and shot (11).
Grit consists of angular metal particles composed of hardened cast steel or
white cast iron. Shot is normally made of the same materials as grit, but it
is spherical in shape. Sho't may also be made of small cut pieces of steel or
aluminum wire for cleaning soft metals. Both grit and shot have a relatively
long life and are capable of being cleaned and reused more easily than any of
the other abrasives. 1
Metallic abrasives produce very little dust, resulting in fewer airborne
particulars. The rounded shot particles are less abrasive than the angular
grit particles and tend to produce a peening action which could deform thin
metal structures. Metallic abrasives are not recommended for cleaning
mobile response equipment because of the high initial cost. After decon-
tamination, the waste abrasive must be disposed of to prevent spread of
contamination.
In summary, the size and composition of abrasives determine their cleaning
effectiveness. The cleaning action of coarse abrasives is difficult to
control and may produce rough surfaces, which are more susceptible to future
contamination. Large particles clean more rapidly than small but may produce
a peening action which could result in deformation of the surface being
cleaned. On the other hand, abrasives that are too small may clean very slowly
but produce less surface damage. The selection of an abrasive to do a par-
ticular job should be based on testing which identifies, the size, shape, and
pressure that produces a good balance of cleaning action and minimal surface
damage.
48
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Dry Ice Blasting
Using dry 1ce pellets as an abrasive 1s considered unique enough to
justify discussing It separately.
Dry Ice pellets are obtained by allowing liquid C02 to expand through a
nozzle to one atmosphere of pressure. Some of the C0j» released will condense
into snow which can be compressed and formed into small pellets, approximately
0.3 cm. in diameter, and used as an abrasive (11). A high-velocity jet
of air and abrasive is then directed onto the surface being cleaned. The
resultant mixture of abrasive and contaminated materials will dissipate as
the dry ice sublimes into gaseous C02, leaving behind only the contaminated
material which can be vacuumed. While reducing the amount or wastes lowers
disposal costs, equipment costs would be more than with ordinary abrasive
blasting because special equipment is needed to handle and store the cold,
pressurized, liquid CQ% and a pelletizer. However, the overall cost is
moderate and less than many other methods.
Dry ice blasting is still experimental and has seen only limited indus-
trial use. It appears to be very useful for removing smearable and less
tightly fixed contamination without abrading metal surfaces. The equipment
being decontaminated should be enclosed to prevent the minimal spread of
airborne contamination. Following decontamination, additional surface treat-
ment to remove residual particles would be unnecessary.
NON-ABRASIVE PHYSICAL CLEANING METHODS
Non-abrasive cleaning methods are physical decontamination techniques
which work by forcing the contaminant with pressure off of the contaminated
surface. In general, less of the metal is removed using non-abrasive methods
than abrasive methods. The following sections review the non-abrasive cl-ean-
ing methods available (see Table 6).
High-Pressure Water
This cleaning system consists of a high-pressure pump, an operator-con-
trolled gun with directional nozzle, and an associated high-pressure hose.
Common operating pressures are from 340 to 680 atm, with resulting flow rates
of 20 to 140 1pm (11). Pressure increases do not always enhance decontami-
nation. The pressure needs to be high enough to remove the contaminant from
the surface without damage. One study reported that 200 atm was the optimum
pressure for physically cleaning vehicles (34). Pressures above a couple
hundred atmospheres start to remove paint, but even pressures higher than 7UU
atm can be used without damaging the surface. One way to prevent impact dam-
age on a surface is to keep the jet moving rapidly over the surface at oblique
anyles.
49
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Nozzle diameter and shape also affect cleaning efficiency. Fan shaped
nozzles produce a spray, while round nozzles produce a jet. Fan nozzles can
be the most effective system if cleaning distance is less than 30 cm, but
remote cleaning, which minimizes worker exposure, is preferable. Round nozz-
les are more efficient for distances beyond 30 cm or when a solid jet nozzle
is oscillating at a relatively high frequency (34). Rigid controls necessary
to ensure optimum jet generation from a nozzle are often not followed. For
example, self propelling mole nozzles are attached to a flexible high-pressure
hose which can bend near the nozzle, restricting proper flow. A minor factor
like this has a major effect on diminishing the jet's cleaning efficiency.
Cleaning efficiency may also be dramatically affected by the addition of
a chemical to the water jet. Chemicals can be added to prevent readhesion of
material mechanically removed from a surface, to enhance decontamination of
areas in which the jet has difficulty penetrating, and to leave a low surface
tension film after liquid cleaning (34). The corrosivity of these additives
must also be taken into consideration on a case-by-case basis.
High-pressure technology is well developed and has been used for many
years; most parts are easily accessible, thus reducing downtime for main-
tenance and repair. It is adaptable for decontamination of various pipe
sizes, equipment, and large planar surfaces. Associated costs should be
relatively low compared to other decontamination methods (11). Application
costs of cold, high-pressure water with a degreaser range from $15 to $20
per m2 (Higgins, 1984). If the water is not filtered and recycled, a large
amount of contaminated water is generated, thereby increasing costs.
Well-bonded surface contaminant films may not be removed by high-pressure
water cleaning. It may be necessary to protect clean areas from back-splash of
contaminated water. The direction of the stream of water must be controlled
to avoid injury. For safety reasons, a valve is generally placed in the gun
so that if the operator trips or loses control, releasing the trigger will
redirect the spray though a large opening.
Ultra-High-Pressure Water
This system is capable of producing a water jet ranging from 1,000 to
4,000 atm (11). Ultra-high-pressure, sprays can remove tightly-adhered surface
films by force of the water. Above 2,000 atm, flexible hoses are not used
and hard piping is required. The velocity of the water ranges from greater
than 500 m/sec at 1,000 atm to 900 m/sec at 4,000 atm. The water can be
discharged through a single nozzle or an array of nozzles. Cleaning the
inside of a pipe is similar to highpressure cleaning, but due to the hard
piping, careful design and reduced flexibility of the system are a concern
when a pressure greater than 2,000 atm is used. Additives can be used to
enhance the decontamination action. Another alternative is to add small
quantities of abrasive material to the less-than 2,000 atm systems. This
technique has been found to be four to five times more effective than using
only water at the same pressure (11).
50
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Ultra-high-pressure cleaning is no more effective than high-pressure
cleaning on many hard, dense, and metal surfaces; however, it does surpass
high-pressure cleaning in removing contaminants that adhere tightly to or are
diffused into the surface. Primary application of the ultra-high-pressure
water jet appears to be for decontamination of concrete surfaces and easily
accessible metal surfaces. Removal of l.b to 3 mm of surface material
occurs easily at 2,000 atm. The cost of using a water cannon to remove sur-
ficial concrete is $200/m2 (35). Concrete surfaces can also be removed by
using a spaller, which consists of a hydraulic cylinder, a push rod, and a bit
with expanding wedges. Associated costs range from $32/m2 for platform
mounted models, to $40/m2 for hand-held models (35).
The basic equipment is commercially available, although-the initial
capital investment is quite high. Waste generation can be kept to a minimum
by recycling wastewater. Equipment is available that surrounds the water
jets and captures the water spray, minimizing overspray. Ultra-high-pressure
water may be a very useful method for removing extremely tightly-adhered
contaminants from concrete or other porous-type surfaces, such as wood.
Although high-pressure water systems are the first choice for decontaminating
dense metal -surfaces, ultra-high-pressure systems should be used when the
decontamination requirements exceed the capability of high-pressure water, for
instance, when the contaminant has diffused into the metal.
High-Pressure Freon Cleaning
FREON cleaning has proved to be a very effective method for cleaning
cloth, plastic, rubber, and external and internal metal surfaces. FREON
113 (trichlorotrifluoroethane) is relatively dense, chemically stable, non-
toxic, non-flammable, and has a high dielectric value (11). It has low
surface tension and leaves no residue. The vapor is easily removed from the
air by activated charcoal. A high pressure (1,000 atm) jet of liquid FREON
113 is directed onto the surface to be cleaned. The FREON is collected in a
sump, filtered, and then reused.
Health Physics, Inc. of Gainesville, Florida, is currently developing
and experimenting with the design for a FREON 113 decontamination unit,
large enough to accommodate a tank, that could be set up on site. Testing
results have indicated that this method is capable of removing PCB residue
and combustion products from internal and external surfaces (Karl Ashley,
Health Physics Inc., personal communication, 1984). Smaller decontamination
chambers are commercially available (11).
Special care must be taken to collect and reuse FREON as it is relatively
expensive. If the air inside an enclosure saturated with FREON vapor is
collected and cooled to condense the FREON, almost all of the FREON can be
recovered.
51
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TABLE 6. SUMMARY OF NON-ABRASIVE PHYSICAL CLEANING METHODS FOR
REMOVAL OF SURFACE CONTAMINATION
REMOVAL OF
BASE METAL
AREA OF
APPLICATION
QUANTITY OF
WASTE PRODUCED
WORKER
EXPOSURE
OVERALL
COST
COMMENTS
HIGH
PRESSURE
WATER
(200-700 atm)
Negligible
Internal/
External
Moderate -
Large
Moderate
Moderate
May not re-
move tightly
adhering
surface films
ULTRA
HIGH
WATER
(1,000-4,000
atm)
Slight
Internal/
External
Moderate -
Large
Moderate
Moderate-
High
Removes
tightly
adhering
contaminants.
HIGH
PRESSURE
FREON
None
Removable
Parts
Small
Low
High
Effectively
cleans
cloth,
rubber, and
plastic.
ULTRASONIC
None
Immersion of
Removable
Parts
Small
Low
Low -
Moderate
Very
effective
for cleaning
small parts.
VACUUM
None
External
Small
Low
Low
Removes
weekly
ad he red, wet
or dry con-
taminants
52
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Ultrasonics
Ultrasonic cleaning applies to small parts that can be removed and
placed 1n a tank filled with chemical solvents, liquids with abrasives, or
detergents. The maximum standard tank size commercially available 1s about
1.5m X .75m X 1m deep, but larger sizes can be special ordered (11). Cleaning
action results from the conversion of electrical energy to high frequency
sound waves which create billions of tiny bubbles in the cleansing solution.
Forming and collapsing these bubbles produce scrubbing action that penetrates
recesses and goes around corners of Immersed parts.
The chemical and physical properties of the cleaning liquid are quite
important in determining its effectiveness. Factors such as vapor pressure,
surface tension, viscosity, and chemical activity are important (11). All of
these are affected by temperature; 1n general, the cleaning ability increases
with temperature up to a point. Typically, the formation and collapse of .
bubbles reach a maximum at about 15°C below the normal boiling point of the
liquid (11).
Undissolved solids can adversely affect cleaning by deflecting or reduc-
ing the ultrasonic energy; therefore, the liquid should be filtered. Reintro-
ducing the filtered liquid back into the tank should be done with minimal tur-
bulence because it will interfere with wave transmission and reduce cleaning
effectiveness. Small objects can be cleaned in a basket (preferably made of
metal since it doesn't absorb ultrasonic energy) immersed in the liquid.
Items should be rinsed after removal from the ultrasonic cleaning tank.
Ultrasonic cleaning equipment is well developed and has proven effective
in industrial use for removing grease and other forms of dirt. Initial
equipment costs would be comparable to most other methods, but the size of
the unit purchased would be the determining factor. The cost of a two-gallon
bench-top unit in a 1981 Labmart catalogue was $540 per unit. Labor disposal
costs would be low, and because the liquids are confined, redistribution of
contaminants would be minimal.
Vacuum Cleaners
A vacuum cleaner for hazardous contamination cleanup consists of a
flexible hose for collection, a canister to support the ultrafiltration
system and contain accumulated waste, and a motor to provide negative pressure
to operate the system (37). Both wet and dry vacuum systems are available
and would be useful to clean the mobile response unit of dust and dirt before
and after the pressure washing.
The design of industrial vacuum cleaners, sizes, and configurations,
vary widely. Filtration systems also vary in terms of their efficiency and
capability for dry and wet pickup. A filter designed specifically for recovery
of toxic and nuisance dusts is called a High Efficiency Particulate Air (HEPA)
filter; it is 99.97 percent effective to 0.008 mm. Activated carbon filters
capable of eliminating vapors from vacuum exhaust are also commercially
53
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available/ Los Alamos Scientific Laboratory has used a specially designed
vacuum cleaning unit equipped with disposable HEPA and activated charcoal
filters to remove spills of aromatic amine cancer suspect agents (16).
Table 7 presents the names, addresses, and phone numbers of several
vendors who supply portable industrial vacuum cleaners. Nilfisk model GS83
with accessories costs $2,652. Another vendor, BVC Beamco, Inc., supplies
industrial vacuum units costing $1,985-$2,280.
TABLE 7. VACUUM VENDORS
1. Hako Minuteman
111 South Route 53
Addison, Illinois 60101
(312) 627-6900
2. BVC Beamco, Inc.
280 .-Polaris Avenue
Mountain View, CA 94043
.(415) 967-6268
3. Nilfisk of America, Inc.
224 Great Valley Parkway
Malvern, PA 19355
(215) 647-6420
Summary of Physical Decontamination Techniques
The more promising methods, because of their practicality and cost- .
effectiveness, include:
o Ultra-high-pressure water at 1,000 atm
o Mechanical methods using brushes
o Wet abrasive techniques.
These methods should be used in conjunction with contamination avoidance
techniques, such as protective coatings. Whether the coating is permanent or
temporary influences the required severity of the cleaning action. Variability
in water pressures used in ultra-high-pressure cleaning makes this technique
adaptable to a variety of surfaces. Wet abrasives can be carefully controlled
54
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so they do not severely abrade surfaces; they help control the release of
contaminant dust, which 1s a severe problem with dry abrasives. Variations
1n bristle hardness and scrubbing time make brushes very adaptable.
Vacuum cleaners may be useful for removing gross part1culate contam-
ination so subsequent steps In the decontamination process can be more effec-
tive. Vacuums may also be effective in cleaning up residual airborne-
deposited grit remaining after abrasive use.
55
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SECTION 6
CASE STUDIES: DECONTAMINATION OF SURFACES
INTRODUCTION
Published studies describing past experiences with chemical decontam-
ination were reviewed to identify techniques with potential applicability to
mobile response units at hazardous waste sites. Three case studies were
developed. They describe:
o Decontamination, of the Binghamton State Office Building
o Decontamination of the Incinerator Ship M/T Vulcanus
o Decontamination of the Three Mile Island Nuclear Reactor No. 2.
Each case study and the relevance of its data is discussed in this
secti on.
DECONTAMINATION OF THE BINGHAMTON STATE OFFICE BUILDING
On February 5, 1981-, a New York State Office Building in Binghamton,
New York, experienced a fire which resulted in the contamination of virtually
all internal building surface areas with PCBs, dibenzodioxins, and dibenzo--
furans. Cleanup activities have focused on the removal of highly toxic
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)(38).
Two methods of surface decontamination using solvent rinses were used
successfully in the Binghamton Office Building. Surfaces readily access-
ible to workers were hand-scrubbed using Triton X-100 cleaning solution.
Inaccessible areas like air ducts were decontaminated by scrubbing with a BMS
Cat cleaning solution. Both Triton X-100 and BMS Cat cleaning solution are
are proprietary formulations containing nonionic detergents. Triton X-100 is
manufactured by Rohm and Haas in Philadelphia, Pennsylvania, and BMS Cat
solution, by BMX of Fort Worth, Texas. These solutions were selected because
of their known low toxicity and ability to remove TCDO (Bob Westin, Versar Inc.
personal communication, 1984).
After vacuuming to remove loose soot and particulate matter, Triton X-
100 was spread on the decontaminated surface, hand-scrubbed, and rinsed with
water. The New York Office of General Services personnel reported that the
56
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X-100 produced acceptable results on nonporous materials such as glass,
metal, and plastic; it has proven unsatisfactory for use with quarry and
ceramic tile (presumably due to the tile's porosity) (Dave Rings, New York
State Office of General Services, personal communication 1984). Versar,
Inc., which is managing the cleanup activities under contract to New York
State, reported that many solvents and detergent formulations were also
successful in cleaning the tiles (Westin, 1984).
Inaccessible air ducts in the building were cleaned by spraying a coat-
ing of BUS Cat, scrubbing the surfaces using sponges on poles, and rinsing
with water. Duct work was then coated with Thoroseal to seal in any contam-
ination which may have been missed (39).
Versar reports that the cleaning reduced surface contamination to a level
of approximately 3 nanograms per square meter or less (Westin, 1984). As of
this writing (June 1985), the New York State Department of Health (DON) has
not determined an acceptable level of surface contamination (John Hawley, New
York State Department of Health, personal communication, 1984). However, the
3 nanograms level detected in the Binghamton facility is well within the con-
tamination levels, ranging from 3.3 to 28 nanograms per meter, now under
consideration by DOH (Hawley, 1984).
Since these clean up activities generated large volumes of water, a
water treatment system was built in the basement of the building to filter or
rinse water before discharging it to the city's sanitary sewer system. This
treatment system filtered contaminated particles by a series of high rate
sand and activated charcoal filters. Large capacity (50,000 liters) and two
medium capacity (19,000 liters) plastic tanks were needed for this treatment
system (39).
Several measures were taken to insure the safety of cleanup personnel de-
contaminating the Binghamton Office Building. A trailer containing security
offices, showers, rest rooms, and lockers positioned at the loading dock pro-
vided the only entry/exit to the building. Before leaving the premises, all
personnel were required to remove protective clothing and to shower thoroughly,
using the showers provided.
Personnel were required to wear Level C protective clothing including:
socks, sneakers, and rubbers; underwear, coveralls, and outer Tyvek protec-
tive suits; and cotton and rubber gloves. It was also mandatory for all
personnel to wear full face respirators featuring activated carbon and high
efficiency particulate filters. After each use, the respirator filters,
Tyvek suits, and hand gloves were discarded. In addition, an Air Pollution
Control System was used to ensure a constant flow of clean outdoor air through
the building (39). Vented air was filtered through the Air Pollution Control
System on the roof before being released outdoors.
Workspace air within the Binghamton Office Building was sampled and
tested before and during rehabilitation of the facility. Before work began,
ambient air samples were gathered from the normal operating areas of the heat-
ing, venting, and air conditioning systems. Throughout the decontamination
57
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process, air Coving through the Air Pollution Control System was tested
periodically. In addition, monthly industrial hygiene samples were taken to
test for PCB levels. As of the date reported, PCB levels well below the
established acceptable level of 0.2 to 0.3 micrograms per cubic meter were
detected (39).
MOTOR TANKER (M/T) VULCANUS DECONTAMINATION
In July and August 1977, U.S. Air Force stocks of Agent Orange were in-
cinerated on the Motor Tanker (M/T) Vulcanus while operating in the Pacific
Ocean. Shipboard surfaces contaminated with 2,3,7,8-TCOD (present in Agent
Orange in an average concentration of 1.9 ppm) were successfully decontam-
inated using separate saltwater and acetone rinses.
Surface contamination of various metal parts of the Vulcanus occurred
once when the incinerator plume impinged on the ship and several times when
small amounts of Agent Orange spilled from the holding tanks. Suspected
areas were tested for contamination by taking wipe test samples. If any
surface contamination was detected, the area was washed with a high-pressure
saltwater spray. Small contamination areas were handscrubbed with acetone-
laden rags and rinsed with water. In every instance, subsequent wipe tests
were taken and revealed n6 detectable herbicide residues. Data describing the
quantities of remaining surface contamination were not available (40).
The Vulcanus storage tanks were decontaminated at the end of each
operation by serial rinsings of herbicide free of, or containing less
than, the 0.02 ppm detectable limit of TCDD. After being completely
drained of waste herbicide, each tank was filled with TCDO free herbicide
to dilute the TCDD content of waste herbicide residuals. The TCDO free
herbicide rinse was transferred from tank to tank until all tanks had been
serially drained and rinsed. As a result, tank TCDD residual contamination
levels were reduced to below 50 mill grams per square meter. All rinsewaters
were incinerated" for final disposal (40).
The air, water, and surface areas used by or exposed to crew members
were regularly tested for TCOD contamination. .Wipe samples of the M/T Vulcanus
surface areas were taken by rubbing an area approximating one square meter
with Whatman 41* filter paper discs. Sample discs were soaked in five mini-
liters of benzene for one half hour before the resultant extracts were analyzed
on board by gas chromatography. Work space air samples were taken at various
places with ten milliliter gas sampling syringes and four stationary work
space air monitors positioned in high traffic areas. The stationary monitors
consisted of a single 3 mm ID glass tube filled with 25 mm of Chromosorb 102*
attached to an air pump. These tubes were changed daily. Potable water
samples, taken after each operation, and the work space air samples were deliv-
ered to a nearby laboratory (Johnston Island Battelle Columbus Laboratories)
to be analyzed by gas chromotography using electron capture detection (40).
Personnel working on the M/T Vulcanus were protected from TCDD contam-
ination in several ways. Areas containing Herbicide Orange were defined and
distinct boundries drawn between contaminated work areas and clean living
areas. After each shift, the protective clothing was discarded in disposal
cans, which were incinerated daily. A shower installed 'directly inside the
58
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contaminated work area was used by personnel leaving the contaminated areas.
In addition to these precautions, the air, surface, and drinking water were
regularly monitored for TCUD contamination (40).
THREE MILE ISLAND DECONTAMINATION
Electropolishiny techniques used to decontaminate radioactive metal
parts at the Three Mile Island (TMI) nuclear reactor have potential application
in decontaminating mobile incinerators at hazardous waste sites. Electro-
polishing is an electrochemical process that produces a smooth, polished
surface on a variety of metals and alloys. Studies have shown it to be a
rapid and effective decontamination technique for metallic surfaces. Electro-
polishing has been used to successfully decontaminate compositions ranging
from steel, copper, and aluminum, to stainless steel and highly alloyed,
corrosion and heat-resistant materials. Electropolishing has been found eff-
ective for contamination that is baked-on, ground-in, or otherwise difficult
to remove using conventional decontamination procedures.
Although electropoTishing solutions are generally based on phosphoric
acid, an electrolyte based on sodium nitrate has been developed for the
electrocleaning of highly radioactive surfaces at TMI. This electrolyte
causes the contamination and the removed.dissolved metals to form a precipitate
that easily separates from the liquid. No data were available describing the
effectiveness of electropolishing in removing nonradioactive surface contam-
ination. However, the fact that 0.05 mm. of the metal surface or more can
be removed by electropolishing indicates that it removes chemical surface.
contamination effectively. It should be noted that electropolishiny is only
effective for decontaminating bare metal and not painted surfaces (41).
- Another advantage of the electropolishing technique is that it may be
used to decontaminate remote, complex, or otherwise inaccessible surfaces.
At TMI, several systems are being developed for usiny the electropolisuing
technique on different surface types. These devices will enable electro-
polishing of large flat walls, pipe interiors, loose metal items, tools, and
fittings. For example, large planar surfaces will be electroyolished by a
mobile device which places an electrolyte pool with a parallel cathode against
a flat contaminated surface. Rough, uneven metal surfaces may be electro-
polished by pumping a stream of electrolyte fluid over the surface through a
cathode lined gun-nozzle. A device is also under design to preclean and
scrub rough surfaces with a porous insulator "sponge" and electrolyte fluid.
Loose contaminated metal items may be electroplated in a tank lined with
cathodes and filled with electrolyte fluid (41).
An electropolishiny technique for decontaminating internal pipe surfaces
has also been developed and successfully tested by United Nuclear Industries
Inc. This device consists of a 60 cm. long tubular cathode placed inside an
electrolyte filled pipe. Each 6U cm. section of uipe is electropolishea tor
20 minutes at a current approximating 1076 amps/m2 before being rinsed with
water. At the conclusion of these electropolishiny treatment tests, the
measured contamination was reduced by about 4 R/hr in..low radiation areas and
by more than 40 R/hr in areas more contaminated with radiation. This electro-
polishing technique, in addition to those previously mentioned, may provide a
versatile means of decontaminating a variety of difficult surfaces (41).
b9
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CASE STUDY CONCLUSIONS
Of these three case studies, only the Binghamton Office Building cleanup
offers tangible results regarding the efficiency of decontamination techniques
for removing dioxin and related compounds. However, the personnel protection
programs and other decontamination methods used and under development for
these cases do provide practical examples for future applications. From the
cases studied, the following conclusions may be drawn:
o Specific nonionic cleaning solutions provide an acceptable means
for decontamination.
o Electropolishing techniques may provide useful methods for chemical
decontamination in the future.
o Several practical methods for ensuring personnel protection include:
1) isolation or distinction of contaminated areas 2) use of
disposable cover suits and yloves 3) installation of showers at
exit points from contaminated area.
Specific evidence on the effectiveness of decontamination was only avail -
. able for the Binghamton Office Building Project. Although the M/T Vulcanus
Technical Report stated that hiyh pressure saltwater rinses and acetone washinys
were effective in reducing TCDU contamination, specific data on test results
were lacking. Therefore, unless actual data become available, defendable con-
clusions on the effectiveness of this method may not be made.
Test results reported from decontamination of the Binyhamton Uffice
Building do prove that dioxin levels of approximately three micrograms per
square meter are achievable using specific nonionic detergents. Since this
level of 3 microyrams/square meter is well below the units now being considered
acceptable by the New York State Department of Health, we conclude that the
nonionic detergents used, BMS Cat and Triton X-1UU, are capable of effectively
removing surface dioxin contamination.
Altnough unproven, the electropolishing techniques employed at Three Mile
Island may be adaptable to chemical decontamination. Chemical contaminants
are likely to be removed during electropolishing; however, unless the contam-
inants are precipitated with the removed surface metal or otherwise.fixed or
degraded, the possibility exists of recontaminatiny the,surface during contact
with the contaminated electrolyte.
Several procedures were successfully implemented to insure the safety of
personnel.working at the Binyhamton Building and aboard the M/T Vulcanus. In
both cases contaminated areas were isolated by specifically defined borders.
Tight security for all personnel entering and exiting the contaminated areas
of the Binghamton Building was easily achieved by sealing all but one access
point to the building.
60
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Although the borders between the contaminated and uncontamlnated areas
aboard the M/T Vulcanus were more difficult to define and monitor, this
system worked effectively on board ship. Personnel Safety plans for both
projects also required that protective clothing including disposable coverall
suits and boots be worn in contaminated areas. Cellulose coveralls used
aboard the M/T Vulcanus were described as effective, comfortable, and in-
expensive (40).
61
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1. U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation.
Final Environmental Statement Related to Primary Cooling System
Chemical Decontamination at Dresden Nuclear Power Station, Unit No. 1.
U.S. Nuclear Regulatory Commission - Final Environmental Statement.
NUREG0686, 1980. 140 pp.
2. Van Wagenen, Harold. Control of Emissions from Seals and Fittings in
Chemical Process Industries. U.S. OHEW-NIOSH Technical Report.
Pub. No. 81-118, April 1981.
3. Adams, William V. Troubleshooting Mechanical Seals. Chemical Engineering,
90(3):48-57, 1983.
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5. McCabe, W.L., and J.C. Smith. Unit Operations of Chemical Engineering.
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6. Mittal, K.L. Surface Contamination Genesis, Detection, and Control,
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7. Ayres, J.A. Decontamination of Nuclear Reactors and Equipment. Ronald
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8. U.S. Environmental Protection Agency. Office of Emergency and Remedial
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9. Shigorina, I.I., A.F. Kapustin, V.G. Shigorin, B.N. Egorov, and A.V.
Kalinken. "Ftorlon" Coats for Corrosion Protection of Electro-
dialysis Units. Chem. i Petro., 18:5/6:242-243, 1983.
10. Bernaolu, O.A., and A. Filevich. Fast Drying Strippable Protective Cover
for Radioactive Decontamination. Health Physics, 19:685-687, 1970.
11. Quadrex Corporation. Evaluation of Nonchemical Decontamination Tech-
niques for Use on Reactor Coolant Systems. Electric Power Research
Institute. EPRI/NP-2690, 1982. 176 pp.
12. Weeks, Jr., R.W,, 8.J. Dean, and S.K. Yasuda. Detection Limits of
Chemical Spot Tests Toward Certain Carcinogens on Metal, Painted,
and Concrete Surfaces. Analytical Chemistry, 48:2227-2233, 1976.
13. Schuresko, D.D. Portable Fluometric Monitor for Detection of Surface
Contamination by Polynuclear Aromatic Compounds. Analytical Chem-
istry. 1980, 52(2):371-373.
62
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14. Vo-Dinh, Tuan. Surface Detection of Contamination: Principles, Applica-
tion, and Recent Developments. Journal of Environmental Sciences.
26:40-43, 1983.
15. Renshaw, Frank M., Ph.D. Decontamination Procedures for Chemical Process
Equipment. CMA/NIOSH Symposium, "Control of Workplace Hazards In
the Chemical Manufacturing Industry." Philadelphia, Pennsylvania,
1981. pp. 159-179.
16. Weeks, Jr., R.W., and B.J. Dean. Decontamination of Aromatic Amine Cancer
Suspect Agents on Concrete, Metal or Painted Surfaces. Am. Ind.
Hyg. Assoc. Journal, Los Alamos, New Mexico. 39:758-762, 1978.
17. Felgl,. Fritz. Spot Tests In Organic Analysis. Elseveler Publishing
Company, New York, New York, 1966.
18. Crummett, W.B., T.J. Nestrick, and L.L. Lamparski. Pesticide Chemistry-
Human Welfare and the Environment/^A4vanced/Good Analytical Tech-
niques Elaborated on the Detection of Polychlorlnated Dlbenzodioxins
in Environmental Samples." In: International IUPAC Congress of
Pesticide Chemistry. Pergamon Press, 1982.
19. Thompson, Joseph H. Guidelines—Design to Minimize Contamination and to
Facilitate Decontamination—Volume II. Equipment and Vehicle
Exteriors. U.S. Army ARRADCOM, Chemical Systems Lab. Special Report.
ARSCL-SR-81005, AD A100300. 1980. 158 pp.
20. Thomson, P.A., J.G. Lamberton, J.M. Witt, and M.L. Deinzer. (Oregon St.
Univ. Dept. Agricultural Chemistry, Env. Hlth. Sci.) Pesticide /
Container Decontamination by Aqueous Wash Procedures. Bulletin of
Environmental-Contamination and Toxicology. 16:528-535, 1976.
21. Gosselin, R.E., H.C. Hodge, R.P. Smith, and M.N. Gleason. Clinical
Toxicology of Commercial Products (Fourth Edition), Williams &
Wilkins Co., Baltimore, Maryland, 1976. -
22. U.S. Environmental Protection Agency. Organic Solvent Cleaners --
Background Information for Proposed Standards. EPA450/2-78-045a,
U.S. EPA, ESE, — Office of Air Quality Planning and Standards,
Research Triangle Park, N.C., 1979.
23. Jackson, Lloyd C. Contaminant Detection Characterization and Removal
Based on Solubility Parameters. In: Surface Contamination Genesis,
Detection, and Control, Vol. 2. Plenum Press, New York, 1979.
24. Nichols, J.A. and 8. Lynch. Dispersant Gels for Treating Surfaces
Contaminated with Residual Oils. Warren Spring Lab., Stevenage
(England) Report No.: LR-327(OP). 1979, 15 pp.
25. Nelson, J.L., and J.R. Divine. Decontamination Processes for Restorative
Operations and as a Precursor to Decommissioning: A Literature
Review. NUREG/CR 1915, U.S. Nuclear Regulatory Commission --
Pacific Northwest Lab, 1981, 89 pp.
63
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26. Ayre*, D.C. (Chapter). F. Coulston, and F. Pocchlari, editors. Acciden-
tal Exposure to Oioxins « Chapter 6. "Oxldatlve Control of Chemical
Pollutants by Ruthenium Tetrode." Academic Press, New York,
1983. pp. 139-145.
27. Taft, et al. Laboratory Handling and Disposal of Chlorinated Dioxin
Waste. In: Human and Environmental Risks of Chlorinated Dioxins
and Related Compounds. Plenum Press, New York, New York, 1983.
28. Kennedy, M.V. Disposal and Decontamination of Pesticides. In:
Proceedings of the 174th Meeting of the American Chemical Society:
Division of Pesticide Chemistry Symposium, American Chemical Society,
Washington, D.C., 1978. 158 pp.
29. Crosby, O.G. (Chapter). F. Coulston, and F. Pocchiari, editors. In:
Accidental Exposure to Dioxins — Chapter 7. "Methods of Photo-
chemical Degradation of Halogenated Dioxins in View of Environmental
Reclamation." Academic Press, 1983. pp. 149-161.
30. Crosby, D.G. and A.S. Wong. Environmental Degradation of 2,3,7,8-Tetra-
chlorodibenzo-p-dioxin (TCDD). Science, 195:1337-1338, 1977.
31. Wong, A.S., and D.G. Crosby, (Chapter) — Cattabeni, F., A. Cavallaro,
and G. Galli, editors. In: Dioxin, Toxicological and Chemical
Aspects Chapter 18, "Decontamination of 2,3,7,8-Tetrachlorodibenzo-
p-dioxin (TCDO) by Photochemical Action." Halsted Press, New York,
New York, 1970. pp. 185-189.
32. Asmus, J.A. and J.H. Brannon. Citric Acid Augmented Flash!amp Cleaning ;
of Corroded Steel Surfaces. In: Proceedings of the 3rd Symposium
on Applied Surface Analysis, University of Dayton, 1981.
33. Maxwell Laboratories, Inc. Flashblast™ Systems--Preliminary Specifi-
cations (descriptive flyer). Maxwell Laboratories, Inc. San Diego,
California, 1980. 3 pp. :
34. Battelle Columbus Laboratories (Multiple Authors). Symposium on Toxic
Substance Control: Decontamination. Chemical Systems Laboratory --
U.S. Army ARRADCOM. AD/A102 107, Columbus, Ohio, April 22-24,
1980. 138 pp.
35. Halter, J.M., R.G. Sullivan, and J.L. Bevan, Surface Concrete Decon-
tamination Equipment Developed by Pacific Northwest Laboratory.
DE82021122, U.S. DOE — Battelle — Pacific Northwest Lab.
1982, 30 pp.
36. Society of Automotive Engineers. SAE Manual of Blast Cleaning. Society
of Automotive Engineers. 29 W. 39th St., New York, New York.
pp. 4-11.
37. Johnston, W.L. and D.E. Clapp. An Evaluation of Vacuum Equipment for
Collection of Asbestos Waste. U.S. Dept.-of Health and Human
Services -- NIOSH. DHHS (NIOSH) Pub. No. 80-137, 1980, 77 pp.
64
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38. Marsi\ R.t J.M. Odato, and G. Roberts. The Tower on Trial (and other
various titles) — collected news reports from cited issue of the
Binghamton, N.Y. Sunday Press, Special Report. The Sunday Press,
Binghamton, New York, February 5, 1984.
39. New York State Office of General Services. The Binghamton State Office
Building Cleanup and Restoration — An Update. New York State Office
of General Services. 1984. 19 pp.
40. U.S. Environmental Protection Agency. Office of Research and Development.
At Sea Incineration of Herbicide Orange Onboard the M/T Vulcanus.
EPAS00/2-78-886.' U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina, 1978.
41. Arrowsmith, H.W. and R.P. Allen. Demonstration of Alternative Decontami-
nation Techniques at Three Mile Island. PNI-SA-8143, U.S. Dept. of
Energy — Pacific Northwest Lab. Presentation for workshop on 3-Mile
Island Reactor Problems, DOE-EPRI, November 27-29, 1979.
42. U.S. Environmental Protection Agency Office of Research and Development.
Guide for Decontaminating Buildings, Structures, and Equipment at
Superfund Sites. EPA/600/2-85/028. March, 1985. Hazardous Waste
Engineering Research Laboratory, Cincinnati, Ohio 45268.
65
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APPENDIX A
FACTORS FOR UNIT CONVERSION
MASS
1 ky = lOOOg = 2.204621b = 2b.27292oz
LENGTH
1m = 100cm = 1000mm = 39.37in
VOLUME
Im3 = 1000 liters = 10&ml = 3b.3145ft3 = 264.17 gallons
PRESSURE
1 atm = 14.696 lbf/in2 (psi) = 29.921 In Hg & 0°C
-------
TECHNICAL REPORT DATA
(neat raw liutmtftotu on the men*
1. REPORT NO.
2.
4. TITLE ANO SU8TIT&E"
DECONTAMINATION TECHNIQUES FOR MOBILE RESPONSE
EQUIPMENT USED AT WASTE SITES (STATE-OF-THE-ART SURVEY)
1. RECIPIENTS ACCESSION NO.
t. REPORT DATE
I. PERFORMING ORGANIZATION CODE
7. AUTHOR(SI
t. PERFORMING ORGANIZATION REPORT NO.
John P. Meade and William 0. Ellis
9. PERFORMING ORGANIZATION NAME ANO AOORESS
JRB Associates
8400 Westpark Drive
McLean, Virginia 22102
1O. PROGRAM ELEMENT NO.
TEJY1A
It. CONTRACT/GRANT NO.
68-03-3113
12. SPONSORING AGENCY NAME ANO ADDRESS
Hazardous Waste Engineering''Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT ANO PERIOD COVERED
Final Report 4/84-5/84
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Mary Stinson (201) 321-6683
16. ABSTRACT
A state-of-the-art review of facility and equipment decontamination, contamination
assessment, and contamination avoidance has been conducted. This review, based on an
Intensive literature search and a survey of various equipment Manufacturers, provides
preliminary background material on the subject. The Information developed here consti-
tutes an important 'head start" for those who need to establish preventive measures,
decontamination plans, and procedures for response personnel and cleanup equipment
used at hazardous waste sites.
The study discusses various decontamination methods, such as use of solvents to
wash off contaminants, use of chemical means to degrade contaminants, and use of physi-
cal means to remove contaminants. Chemical and physical testing methods designed to
assess the nature of the contaminant and the quantity and extent of contamination were
also investigated. Also discussed in (his report are procedures that can be used to
prevent contamination of response equipment and personnel. These preventive procedures
are: enclosures to prevent spread of contaminants, safety features on response equipment
to prevent spills and leaks, protective coatings on response equipment surfaces, and
protective clothing and furnishings for personnel. Three case studies were also reviewed:
the Three Mile Island cleanup, the "Vulcanus* incinerator ship cleanup (dioxins and PCBs).
and PC8 cleanups in Binghamton, Hew York. The review has identified several methods that
could be of value in effectively decontaminating response equipment units such as a mobile
incinerator at a reasonable cost.
7.
KEY WORDS ANO DOCUMENT ANALYSIS
DESCRIPTORS
b.lOENTIFIERS/OPEN ENDED TERMS
COSATi Field/Group
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (Tliit Rrporil
UNCLASSIFIED
21. NO. Of PAGES
20 SECURITY CLASS iThil fHftl
22. PRICE
UNCLASSIFIED
EPA F»»m 2220-1 (R«». 4-77) Previous COITION i* O«*OLCTC
-------
United State*
Environmental Protection
Agency
Office of Solid Waste
and Emergency Retponie
Washington DC 20460
SW-871
September 1982
&EPA
Management of
Hazardous Waste Leachate
U.S. £nvironm6htal P:
Region 5, Library (F1
77 West Jackson 6,
Chicago, IL 60604 .
Agency
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