United States
Environmental Protection
Agency
Industrial Environmental Research^
Laboratory
Research Triangle Park NC 27711
&ER&
Research and Development
EPA-600/S2-82-069 July 1982
Project Summary
Interim Guidelines for the
Disposal/Destruction of
PCBs and PCB Items by
Non-Thermal Methods
E. M. Sworzyn and D. G. Ackerman
This report summarizes an interim
resource and guideline document in-
tended to aid USEPA regional offices
in implementing the PCB Regulations
(40 CFR 761) with regard to the use of
non-thermal methods for the destruc-
tion/disposal of PCBs.
The interim report describes and
evaluates various alternative chemical,
physical, and biological PCB removal
and/or destruction technologies, in-
cluding carbon adsorption, catalytic
dehydrochlorination, chlorinolysis.
sodium based dechlorination, photo-
lytic and microwave plasma destruc-
tion, catalyzed wet-air oxidation, and
activated sludge, trickling filter, and
special bacterial methods.
Alternative destruction/disposal
technologies were evaluated using
technical, regulatory, environmental
impact, economic, and energy require-
ments criteria. Because the technol-
ogies investigated are at various stages
of development (only the sodium based
dechlorination processes are now com-
mercially available), data deficiencies
exist, and good engineering judgment
was used to supplement available
quantitative information.
Of the technologies evaluated, many
show the potential for greater than 90
percent PCB destruction with mini-
mum environmental impacts and low
to moderate economic costs. These
technologies are catalytic dehydro-
chlorination, sodium based dechlorina-
tion, microwave plasma, and photo-
lytic processes.
' This Project Summary was devel-
oped by EPA's Industrial Environmen-
tal Research Laboratory, Research
Triangle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
Polychlorinated biphenyls (PCBs) are
derivatives of the compound biphenyl in
which 1 to 10 hydrogen atoms have
been replaced with chlorine atoms. PCBs
have extremely high chemical and ther-
mal stability, making them quite useful
in many commercial applications (e.g.,
as dielectric fluids in capacitors and
transformers; in heat transfer and hy-
draulic systems, pigments, plasticizers,
carbonless copying paper, and electro-
magnets; and as components of cutting
oils).
Their wide use and the lack of recogni-
tion of their hazards have led to their
wide distribution in the environment
(Fuller et al., 1976). Although PCBs
have fairly low acute toxicities, some
adverse effects have been found in
humans, laboratory animals, and other
organisms. There is some evidence that
PCBs bioaccumulate and may be car-
cinogenic (Fuller et al., 1976).
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Concern over the PCS contamination
problem led to a provision in the Toxic
Substances Control Act (TSCA) that will
require the eventual elimination of the
use of PCBs in the U.S. The PCS Regu-
lations, promulgated under TSCA (40
CFR 761), do not require removal of
PCBs and PCS items from service earlier
than would otherwise be required; but
when PCBs and PCB items are removed
from service, disposal must be in ac-
cordance with the PCB Regulations.
Other acts which govern the disposal of
PCBs include: the Resource Conserva-
tion and Recovery Act, the Clean Water
Act, the Clean Air Act, the Occupational
Health and Safety Act, and the Marine
Protection, Research, and Sanctuaries
Act.
Because there is a large amount of
PCB in existence that will need disposal,
the Electric Power Research Institute
projected a shortfall of utility waste PCB
disposal capacity (landfill and inciner-
ator) in most EPA regions after January
1, 1980 (EPRI, 1979). In addition, there
will be a smaller quantity of waste PCBs
from commercial and industrial uses
which will require disposal.
The PCB Regulations provide for four
general disposal methods:
• Annex I incinerators for PCBs and
PCB items having greater than
500 ppm PCB content.
• High efficiency boilers for PCB-
contaminated liquids having PCB
contents 50 ppm or greater but not
greater than 500 ppm.
• Annex II chemical waste landfills
for PCB-contaminated liquids
(equal to or greater than 50 ppm
but not greater than 500 ppm);
non-liquid PCBs in the form of
contaminated soils, rags, or other
debris; and all dredged materials
and municipal sewage sludges
that contain PCBs.
• Other approved method for PCBs
and PCB items that are subject to
incineration.
The full report is an interim guidelines
document applying solely to the dis-
posal/destruction of PCBs by methods
other than incineration in Annex I
incinerators or high efficiency boilers.
Annex II chemical waste landfills, or as
municipal solid waste.
Evaluation Criteria for
Non-Thermal PCB Destruction
Processes
Since the EPA considers non-thermal
PCB destruction processes as alternative
methods to incineration, the basis for
evaluation of an alternative (non-
thermal) system is its performance
relative to a thermal system. As stated
in the PCB Regulations, 40 CFR
761.10(e), an alternative system must
be demonstrated to "achieve a level of
performance equivalent to Annex I
incinerators or high efficiency boilers."
Before approving any non-thermal de-
struction process, the Regional Admin-
istrator must be able to determine that
the alternative system provides "PCB
destruction equivalent to" the appropri-
ate thermal method and "will not pre-
sent an unreasonable risk of injury to
health or the environment."
Chapter 2 of the full report describes
the development of an evaluation meth-
odology which is not process specific. It
involved taking characteristics of any
given non-thermal process and compar-
ing them with criteria related to the
regulatory, technical, environmental,
economic, and energy performance
characteristics of thermal processes.
Technical factors which should be
included in an evaluation of a non-
thermal process are: destruction effi-
ciency, range of PCB concentrations in
the waste, ability of the process to
handle wastes of varying PCB content,
physical form of PCBs the process can
handle, restrictions on non-PCB waste
constituents, special process require-
ments, state of the technology, overall
facility design and operation, and re-
source reclamation. Environmental
factors which should be included in the
overall evaluation are: environmental
impacts of the disposal operation itself,
environmental impacts of disposal of
process wastes, potential impact of
accidents and transportation of PCBs to
the disposal site, effluent monitoring
programs, and closure and post-closure
plans. Economic factors considered in
the overall evaluation are: capital costs
or the cost of facility construction or
modification, operating costs, disposal
costs, credits for products or by-products,
financial requirements related to closure
and post-closure monitoring and main-
tenance, and regulatory costs. Energy
factors that should be included in the
evaluation are: debits, credits, and re-
source recovery.
Most of the above regulatory, techni-
cal, environmental, economic, and
energy factors are discussed for num-
erous alternative disposal methods in
the full report.
Non- Thermal Destruction
Methods
The non-thermal destruction pro-
cesses described in this report are
grouped into two broad categories:
physicochemical methods and biological
methods. Physicochemical methods ex-
ploit chemical or physical characteristics
of PCB molecules to achieve destruction
or detoxification. Biological methods all
employ microorganisms which metabo-
lize PCB molecules to less chlorinated'
PCBs or non-chlorinated compounds.
None of the alternative methods de-
scribed here or in the full report are at
commercial scale, so that only limited
data are available. There are, therefore,
substantial technical, environmental,
economic, and energy information gaps.
Some of the methods have not been
applied to PCB degradation but offer
interesting possibilities. Other methods
have been applied to PCBs only in dilute
aqueous solution, but are covered be-
cause of potential adaptability to PCBs
in dilute organic solution (e.g., mineral
oil dielectric fluid). Comparison of these
alternative methods with thermal
methods is necessary, but many of the
comparisons are necessarily qualitative.
Destruction efficiencies, for methods
that have been so tested, are well below
the performance requirements of Annex
I incinerators or high efficiency boilers.
Currently, none of the alternative meth-
ods meet the destruction efficiency
requirements of the PCB Regulations.
However, destruction efficiency is only
one factor that must be considered in
the approval process.
Table 1 presents a comparison of
technical, environmental, economic,
and energy factors associated with
thermal (Annex I incinerators and high
efficiency boilers) and non-thermal
destruction/disposal methods.
Adsorption Processes
Adsorption processes are useful for
removing chlorinated hydrocarbons
from an aqueous waste stream by
contacting it with activated carbon by
passing it through a vessel filled with a
carbon slurry or granules. Impurities
from the aqueous stream are removed
by adsorption onto the carbon. Activated
carbon has an affinity for organics, and
its use for organic contaminant removal
from wastewater is common.
In 1976, General Electric's Capacitor.
Products Department installed a system!
to eliminate the discharge of PCBs to the
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Table 1 . Comparison of Thermal and Non- Thermal Disposal/ Destruction Methods
Current Status
Potential for of Technology
Destruction or Large Scale as Applied to Destruction
Conversion Method Application PCB Processing Efficiency Feedstock
Annex 1 Incineration High 1 >99.99% g,l,s
High Efficiency Boilers High 1 >99.99% 1
Activated Carbon Absorption
Processes High 3 Not applicable a
Catalytic Dehydrochlori-
nation Medium 2 99+% l,g
Chlorinolysis Low 3 Low 1
Goodyear Process High 3 92% 1
Microwave Plasma Medium 2 95% l,g
Ozonation Processes Medium 3 Not applicable a
Photolytic Processes Low 2 90-95% 1
Sodium-Oxygen-Polyethyl- Medium 2 95% 1
ene Glycol
Sunohio Process High 3 99+% 1
Catalyzed Wet Air Oxidation Medium 2 99+% a.l.s
Activated Sludge Low 3 Not applicable a
Trickling Filter Low 3 Not applicable a
Special Bacterial Methods Low 3 Not applicable a
1 Method is currently used commercially.
2 Proven research method only.
3 Limited or no data base.
4 Potential controllable method with minimum environmental impact.
5 Potential solid residue or wastewater disposal problem.
6 Low capital investment and moderate operating costs.
7 Moderate capital investment and operating costs.
8 Large capital investment and operating costs.
9 Resource recovery option.
10 Requires recycling or disposal of adsorption medium.
1 / Potential residual toxicity of by-products.
12 Potential return on investment.
s Solid
a Aqueous
g Gas
1 Liquid
Hudson River from its Hudson Falls and nated with PCBs (Arisman, 1 979), but
•Fort Edward manufacturing plants. This was not very cost effective. High cost
Pdsorption process worked extremely and carbon disposal or regeneration
well for dilute aqueous streams contami- requirements caused EPA and GE to
PCB Overall Overall
Range, Environmental Economic
ppm Impact Impact
>50 4.5 8
<50 4,5 8
Dilute
amounts 4,5, 10 7,9
<50 5,11 7,9
Not 4,5 8,9,12
applicable
<500 4 6,9
50-500 4,5 7
Dilute 5,11 8
amounts
<50 5,11 7
50-500 11 7.9.12
and >500
50-500 4 6.9.12
and >500
50-500 3 7
and>500
Dilute 1 1 7
amounts
Dilute 1 1 7
amounts
Dilute 1 1 7
amounts
investigate alternate treatment systems;
i.e., UV-Ozonation and catalytic reduc-
tion.
Application of activated carbon ad-
sorption processes is less common to
non-aqueous streams. A study (U.S. Air
Force, 1976) on using activated carbon
to remove the 2,3,7,8-tetrachlorodi-
benzo-p-dioxin (TCDD) contaminant
from Herbicide Orange concluded that,
though the process was technically and
economically feasible, the technology to
dispose of the TCDD contaminated
charcoal did not exist. Therefore, Herbi-
cide Orange stocks were successfully
incinerated at sea (Ackerman et al..
1978).
From a technical point of view, adsorp-
tion processes for removing organic
compounds from liquid streams are
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attractive because they offer the possi-
bility of resource recovery; e.g., removal
of PCBs from mineral oil dielectric fluids
with possible reuse of the mineral oil.
However, to be economical, the PCBs
must be removed from the adsorbent, so
that an adsorption process applied to
PCB disposal must be coupled with a
second disposal/destruction process to
handle PCBs removed from the absorb-
ent during regeneration of the activated
carbon.
Catalytic Dehydrochlorination
Catalytic dehydrochlorination is based
on the reaction of polychlorinated hydro-
carbons with hydrogen gas under high
pressure in the presence of a catalyst
(LaPierre et al., 1977). The reasoning
behind this reaction is that partially
dechlorinated or nonchlorinated com-
pounds could be less toxic and, there-
fore, could be biodegraded more easily
than highly chlorinated compounds. This
process has been applied directly to the
detoxification of PCBs, but only on thelaboratory
scale. A study at the Worcester Poly-
technic Institute indicates a complete
conversion of PCBs into dechlorinated
biphenyls (LaPierre et al., 1977).
Catalytic dehydrochlorination should
be able to handle a wide range of PCB
contaminated material, if they are in the
liquid state. Transformers with a PCB
concentration of > 500 ppm, as well as
PCB capacitors and mineral oil dielectric
fluids with PCB contents of 50-500
ppm, should be amenable to treatment
by this process.
Potential impacts of the disposal
operation, as well as the disposal of
process wastes, should be low. Accord-
ing to current studies, a properly de-
signed process should not produce toxic
off-gases or contaminated aqueous
residues.
Lack of economic data prohibits a cost
assessment of a dehydrochlorination
conversion facility. Hydrocarbons pro-
duced by this process could be used or
sold as fuel oil. This economic credit
could lower the cost of PCB processing
substantially. Qualitatively, capital in-
vestment and operating costs appear to
be moderate.
Chlorinolysis
Chlorinolysis is an established tech-
nology for converting chlorinated hydro-
carbons to carbon tetrachloride. This is
a vapor-phase reaction in which chlorine
is added to the waste material under
high pressure and low temperature (or
high temperature and low pressure). A
catalyst is not used in this process
(S.S.M., 1974). If the waste consists of
only carbon and chlorine atoms, the
product will be carbon tetrachloride. If
the waste contains oxygen or hydrogen,
carbonyl chloride and hydrogen chloride
are also produced (S.S.M., 1974).
Chlorination as a method of disposing
of hazardous wastes was first suggested
in 1974. FarbwerkeHoeschstAg, Frank-
furt/Main, Germany, has developed a
process in which hydrocarbons and their
chlorinated derivatives are completely
converted to carbon tetrachloride and
hydrogen chloride at pressures up to 24
MPa and temperatures up to 893 K
(Krekeler et al., 1975).
Chlorinolysis has not been applied
directly to PCB disposal, but a variation
of the process may be adaptable. Al-
though the Hoeschst Chlorinolysis pro-
cess can handle chlorinated benzene
derivatives on a limited scale only, it
may be worthy of evaluation.
The feed must be a liquid, and most
impurities must be removed before
processing. Chlorinolysis works best on
aliphatic compounds.
The destruction efficiency for PCBs
should be extremely low in the existing
process since aromatic compounds are
not processed efficiently. The process
works poorly for an aromatic content of
greater than 5 percent calculated as
benzene.
Potential environmental impacts
when considering the construction and
operation of a Chlorinolysis plant include
shipment and handling of the hazardous
organochlorine wastes prior to chlorin-
olysis, control of the potential gas and
liquid effluents after conversion, and
handling and storage of the final prod-
ucts. Emissions from manufacturing,
storage, and transport of polychlorinated
aromatics (particularly PCBs) are pos-
sible. Accidental spills and leaks of both
solid and liquid wastes are the primary
sources of emissions. Conventional spill
and leak prevention procedures should
make the process operationally safe.
The Goodyear Process
The Goodyear Tire and Rubber Com-
pany recently developed a process to
degrade microquantities (e.g., 120 ppm)
of PCBs (Goodyear, 1980). This process
involves preparing sodium naphthalide
and contacting this reagent with the
PCB-containing liquid. The reagent ab-
stracts chlorines from the PCB molecule,
and NaCI and non-halogenated poly-
phenyls are formed. The reaction h
rapid at room temperature.
The Goodyear process appears wel
developed on the laboratory scale. Thi
available literature source indicates onl<
that the Goodyear process is technical!)
applicable at this time to handle mixture:
of Aroclors (a Monsanto trademark) a
50-500 ppm concentrations.
Undestroyed PCBs remain in th<
processed heat transfer fluid. This fluic
could be recycled or reused directly, sc
that there is no real environmenta
impact expected from this process efflu
ent. Overall, the potential environmenta
impacts of the disposal operation appeal
to be low although a thorough assess
ment cannot be made without more tes
data.
Generally, the Goodyear process ap
pears to be relatively low in cost am
may be adaptable to both small anc
large scale operation. A detailed eco-
nomic evaluation is needed before this
process may be judged economically
justifiable. With large scale application
product recovery of purified mineral oi
may reduce costs significantly.
Microwave Plasma Methods
Lockheed's Palo Alto Research Labor
atory (LPARL) has developed a process
to destroy PCBs and other hazardous
materials by microwave plasma treat-
ment (Oberacker and Lees, 1977). Re-
search started on the bench scale anc
has been expanded to a unit which car
successfully destroy PCBs at the rate o1
0.45-2.3 kg/hr. A future goal is tc
develop a 40-50 kg/hr version.
A 15 kW microwave plasma reaction
system capable of destroying 2-11 kg/hi
of organic wastes, including PCBs, is
now in operation. Laboratory scale
experiments have determined that the
destruction efficiencies of Aroclor 1242
and 1254 are 99 percent using 4.6 anc
4.5 kW microwave power, respectively,
The process should be able to destroy
PCB concentrations of 50-500 ppm
effectively. Further research is needed
to determine the maximum concentra-
tion of PCBs that can be destroyed with
a high destruction efficiency.
Although microwave plasma destruc-
tion of PCBs is a controllable method
which yields innocuous products, such
as CC>2 and HjO, potentially hazardous
products such as CO and organochlor-
ines will also be produced.
An environmental assessment of thi
microwave plasma disposal operation
must consider the shipment and hand-
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I ing of the PCB material prior to process-
ing, control of the potential gas and
liquid effluents after conversion, and
the handling, storage, and disposal of
final products. Extremely high tempera-
tures and pressures occur throughout
the system. Special safety techniques
would have to be used to guard against
the accidental release of hot, corrosive,
or toxic vapors. The use of a caustic
scrubber should keep emissions fairly
low. Since the effluent streams from a
scrubber are mainly liquid, any particu-
lates emitted would be dissolved in the
liquid effluent as suspended particles.
Very little information exists on the
economics of a microwave plasma pro-
cess adapted to PCB destruction. Over-
all, capital costs for a microwave plasma
processing facility may be high since
useful by-products may not be recover-
able. Electrical costs should decrease as
microwave power technology advances.
Future improvements in basic plasma
design should reduce operating costs.
Currently, it appears that a large-scale
microwave plasma destruction unit will
entail moderate capital investment and
operating costs.
Ultraviolet-Ozonolysis
Ultraviolet (UV)-ozonolysis is a process
that destroys or detoxifies hazardous
chemicals in aqueous solution utilizing
a combination of ozone and UV irradi-
ation. Fairly simple equipment is re-
quired on the laboratory scale: a reaction
vessel, an ozone generator, a gas dif-
fuser or sparger, a mixer, and a high
pressure mercury vapor lamp (Wilkinson
et al., 1978). UV-ozonolysis has proved
to be effective in destroying dilute
quantities of PCBs in industrial waste
water effluents. Experimentation has
been on the laboratory level only. Scale-
up to pilot plant capacity has not been
attempted.
UV-ozonolysis of dilute aqueous
streams contaminated at various PCB
levels was performed by General Elec-
tric's Capacitor Products Department at
its Hudson Falls and Fort Edward manu-
facturing plants (Arisman, 1979). De-
struction efficiencies for most experi-
ments were 93 ± 3 percent. PCB
concentrations ranged from 30 to 100
ppb in aqueous solution.
The possibility of the formation of
reaction products, harmful to aquatic
life, must be considered. Residual
amounts of halogenated compounds, as
well as trace metals, may be contained
in the waste effluents. An assessment
of the types of final products that will be
produced is necessary. Any auxiliary
disposal operations such as adsorption,
filtration, or incineration must also be
analyzed for possible environmental
impact.
Major capital equipment costs will be
the reactor, ozone generator and power
supply, and the UV irradiation source
and power supply. Major operating costs
include electrical energy and labor. In
general, UV-ozonolysis should be cost
competitive with traditional waste water
processing facilities.
Photolytic Methods
Photolytic processes are based on the
principle that UV radiation activated
molecules which may then under-
go chemical reaction. Much research
has been done on the photodecomposi-
tion of various classes of pesticides by
using UV radiation (Crosby and Li, 1969;
Plimmer, 1970, 1972, 1978; Rosen,
1971; and Mitchell, 1961). The photode-
composition of PCBs is now being
studied in the laboratory to determine
products formed and the effects of
solvents on product formation and rates
of reaction (Ruzo et al., 1974).
Currently, very little is known about
the photochemical properties of the many
PCB isomers. A few studies have shown
that the primary reaction at wavelengths
> 290 nm is stepwise dechlorination.
The actual dechlorination products have
rarely been identified (Ruzo etal., 1974).
In 1974, a study was carried out to
determine the reaction products of PCB
photodecomposition in different sol-
vents (Ruzo et al., 1974). It was con-
cluded that if photolysis is to occur, the
PCB molecule must absorb light energy
above 290 nm or receive energy from
another molecule through an energy
transfer process. The product may be a
complex mixture in which isomerization,
substitution, oxidation, or reduction
processes have occurred. To date, there
have not been any studies of photolysis
of PCB-contaminated mineral oils or
hydraulic fluids.
Destruction efficiencies as such have
not been determined in these laboratory
studies. A 90-95 percent yield of de-
chlorinated PCB in methanol solution
has been determined (Ruzo et al., 1974).
Methanol substitution products were
also found in these experiments.
The photolysis process may be appli-
cable over a wide range of PCB concen-
trations. The important factor determin-
ing the concentration range of the PCBs
is its solubility in the solvent. Research
has not been done on an actual PCB-
contaminated mineral oil, so that the
applicability of this process to PCB
disposal/destruction has not been com-
pletely validated.
The precise chemical nature of the
process wastes needs to be investigated
before assumptions about process waste
disposal impacts on the environment
can be made. Certain chlorinated com-
pounds may exist in the waste streams
that could be harmful to the environ-
ment. Vapor effluents could contain HCI
and photoactive compounds. Aqueous
effluents could contain chlorine and
components that did not react with the
UV radiation.
Factors that will affect overall capital
and operating costs for a large scale
photolysis processing plant include land
availability and cost, types of chemicals
and reagents required, labor, monitor-
ing, and application costs. Based on the
limited information available, scaled up
operating and capital costs appear to be
moderate. Possible economic credits
could accrue if some of the products are
saleable or reusable.
Chemical Degradation with
Sqdium-Oxygen-Polyethylene
Glycol
Reaction of PCBs with sodium-
oxygen-polyethylene glycols is based on
the fact that sodium metal finely dis-
persed in certain solvents can serve as a
chemical reactant. The reactivity is
dictated by the mechanism of decompo-
sition of the PCB molecule. Laboratory
experiments have shown that the react-
ing solution should be composed of
polyethylene glycol (avg M.W. = 400,
dried over anhydrous Na2SCU) and
metallic sodium. PCB oil is added to this
solution to produce polyhydroxylated bi-
phenyls and hydroxy-benzenes (Pytlewski
et al., 1980). This technology exists on
the laboratory scale only.
Laboratory studies have indicated an
approximate 95 percent conversion of
the PCB oil. Precise destruction effici-
encies have not been determined. The
process appears to be applicable over a
wide range of PCB concentrations,
particularly in the 50-500 ppm range.
Large amounts of H2 gas and NaCI will
be evolved in this process. The Hz gas
should be drawn off and collected as a
source of energy. NaCI disposal should
not create any special disposal problems.
The recovered H2 gas could be used as
an additional source of energy to melt
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the NaCI. The evolution of large amounts
of Hz gas means that the use of open
flames, electrical sparking, and electric
heating elements must be avoided. The
reaction with the sodium metal should
be started with heat supplied by steam.
Franklin Research Center engineers
made a preliminary cost evaluation for
the commercial destruction of PCBs by
this process. They determined decompo-
sition cost of almost 70C/kg of PCBs
(Pytlewskietal., 1980). Recovery credits
for H2 gas and the polyhydroxylated
biphenyls could bring the cost of the
operation low enough to make the
process profitable.
The Sunohio Process
Sunohio has developed a process to
break down the PCB molecule into its
two primary components, biphenyl and
chlorine. The chlorines are converted to
chlorides, while the biphenyl molecule
is converted to polymeric solids. The
process is called PCBX, a Sunohio trade-
mark. Full scale stationary and mobile
units are now complete. The unit is
designed to: (1) heat transformer oil and
filter it, removing moisture, acids, and
other contaminants; (2) remove and
destroy PCBs contained in the trans-
former oil but not the oil itself, and (3)
destroy pure PCBs. The equipment,
contained in a large tractor/trailer, is
self-contained and either can generate
its own power or may be hooked up to an
external electric power source. Trans-
former oils can be removed from fully
charged transformers and, after treat-
ment, can be returned to the same
transformer in minutes.
The original goal in process develop-
ment was to remove all PCBs from the
treated fluids. Experimental fluids used
for laboratory studies have contained as
little as 100 ppm and as high as 10,000
ppm PCBs. These fluids after treatment
are clafmed to have contained 0 to 40
ppm PCBs, respectively. The process
appears to be able to handle a wide
range of PCB concentrations and types
of fluids.
An environmental impact study has
not been carried out for the PCBX
process. Each generic effluent stream
should be analyzed for composition and
percent solids. Overall, the potential
environmental impact of the disposal
operation appears to be very low. Sun-
ohio claims that either very little or no
toxic products will be produced.
A cost analysis of the PCBX process is
not available. It appears that a major
capital investment is not required since
the system is completely portable. It is
claimed that transformer oil can be
decontaminated for about $264-$792
per m3. The theoretical reagent cost is
about $1.10 per kg (Sunohio, 1980).
Cost credits may be earned by reusing
the decontaminated heat transfer oil
instead of discarding it.
Catalytic Wet Air Oxidation
Wet air oxidation is based on the
principle that a solution of any organic
material can be oxidized by air or oxygen
if enough heat and pressure are applied.
At temperatures of 433-613 K and
pressures of 3.1-17.2 MPa, sewage
sludges will be oxidized to alcohols,
aldehydes, and acids. At higher tempera-
tures and pressures, the organic mate-
rial can be oxidized to CDs and Hz (Astro,
1977).
IT Enviroscience (ITE), Inc., recently
developed a catalyzed wet air oxidation
process for the destruction of PCBs. This
process is patented and involves the
direct oxidation of PCBs by air or oxygen
in an acidic aqueous medium at high
temperatures. This process can be used
for organic material in aqueous solution,
organic liquid residues, and specific
types of sludges and solid residues.
Special attention was given to PCBs in
the development of this process (IT
Enviroscience, 1980). This catalyzed
wet air oxidation process utilizes a water
soluble, single-phase catalyst system. It
differs from other processes in that the
catalyst is homogeneous, and, unlike
uncatalyzed wet air oxidation, heat and
pressure requirements are lower. The
catalyst itself is used to promote the
necessary oxygen transfer.
This technology is new and not com-
pletely researched. ITE recently com-
pleted feasibility testing and process
development studies for the destruction
of PCBs. Over 50 tests were made on
PCBs by ITE in a 1 liter titanium stirred
reactor to define process conditions in
the laboratory. Greater than 90 percent
of PCBs were repeatedly destroyed by
oxidation at 523 K for 2 hours. It is
important to note that it is not necessary
to achieve 99+ percent destruction of
the PCBs since unreacted PCBs will
remain in the reactor until destroyed.
(This retention of undestroyed PCBs
reduces throughput.) The laboratory
studies used 5-6 g of Askarel (56 percent
PCBs and 44 percent trichlorobenzene)
to determine destruction efficiencies.
This process may be adaptable over a
wide range of PCB concentrations.
Transformer oils with > 500 ppm PCBs
might possibly be treated by this process.
It is extremely difficult to estimate
environmental impacts at this time. It
appears that minimal environmental
damage would be expected from this
PCB disposal operation since the PCBs
remain in the reactor until destroyed
and since there is no aqueous bottoms
product. COz, N2, H20 vapor, volatile
organics, and inorganic solids leave the
reactor. The water and condensable
organics are retained in the reactor for
complete degradation. This step reduces
the volume of toxic organic substances
that could be contained in the effluent
streams. The vent gases are low in
volume and could be treated by conven-
tional techniques. Further research is
required to develop a detailed environ-
mental assessment of this process.
Economic data for the ITE method are
not available. Required information in-
cludes: (1) capital costs, (2) operating
costs, (3) disposal costs, (4) credits for
products or by-products, and (5) regula-
tory costs. A cost analysis and feasibility
study is currently being carried out by
ITE to determine the economic viability
of this process. Qualitatively, this pro-
cess seems to be economically feasible
if adequate throughput can be attained.
Little or no added energy is required,
and no auxiliary fuel is consumed.
Chemical consumption is low, lowering
the cost appreciably.
Biological Methods
Biological disposal methods are all
based on the ability of microorganisms
to degrade toxic organic compounds, such
as PCBs. The major differences between
the various methods lie in the means of
supporting and contacting the micro-
organisms with the fluid containing the
species to be degraded, means of provid-
ing oxygen to the microorganisms, and
in pre- and post-treatment.
The literature review indicated that
most commercial applications of biolog-
ical processes are to aqueous streams
containing relatively small amounts of
organic compounds. Laboratory studies
show that pure Aroclor mixtures are
degraded and that degradation rates are
inversely related to increasing chlorine
substitution. Studies (U.S. Air Force,
1976) show that microorganisms could
degrade concentrated Herbicide Orange
components over a period of years,
Commercial land farming is used to
degrade oil-contaminated industrial
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aqueous wastes. However, PCBs are
more refractory than the major Herbicide
Orange components and oils. Two bio-
logical processes that may be of some
interest are activated sludge and trick-
ling filter methods. Both processes are
currently used for wastewater treat-
ment.
Activated Sludge Treatment
Activated sludge treatment is classi-
fied as an aerobic process because the
microbial solution is suspended in a
liquid medium containing dissolved
oxygen. Complete aerobic treatment
without sedimentation is carried out as
the wastewater is continuously fed into
an aerated tank where microorganisms
digest and flocculate the organic waste.
The microorganisms (activated sludge)
settle from the aerated liquor in a final
clarif ier and are returned to the aeration
tank. The effluent emerges from the
final settling tank purified.
Tucker, Litschgi, and Mees (1975) did
laboratory testing with a continuous
feed activated sludge unit. With a feed
rate of 1 mg/48 hrs, they reported an 81
percent degradation of Aroclor 1221,33
percent degradation of Aroclor 1016,26
percent degradation of Aroclor 1242,
and 15 percent degradation of Aroclor
1254.
Trickling Filter Methods
Trickling filters consist of crushed
rock, slag, or stone. These materials
provide a surface for biological growth
and passages for liquid and air. The
primary treated waste flows over the
microbial surface. The soluble organic
material is metabolized, and the insol-
uble material is adsorbed onto the media
surface (Wilkinson et al., 1978). The
biological components are bacteria,
fungi, and protozoa. The bottom portions
of the filter contain nitrogen fixing
bacteria. Trickling filters are classified
as low (standard), intermediate, high, or
super rate filters based on hydraulic and
organic loading rates. Since an aqueous
medium is necessary, only dilute dis-
solvable PCB isomers may readily be
contacted with the active microbes.
Neither of the above biological meth-
ods can be considered technically appli-
cable to general disposal of PCBs and
PCB items. While trace quantities of
PCBs could be fed into a commercial
scale process and while some degrada-
ion would occur, destruction would not
je complete, and the amounts fed would
be so small as not to aid appreciably the
PCB disposal problem. Further research
is warranted, but the research might
most profitably be pursued in the follow-
ing areas: (1) more effective treatment
of sewage and wastewater already con-
taminated by PCBs, (2) treatment of
PCB-contaminated dredge spoil,' and (3)
developing microorganisms effective at
degrading PCBs. Because destruction
efficiencies of current processes de-
crease rapidly with increasing chlorine
substitution, it is doubtful whether any
activated sludge or trickling filter process
will be capable of destruction effici-
encies equivalent to those of high
efficiency boilers or Annex I incinerators.
References
Ackerman, D. G., et al. 1978. At-Sea
Incineration of Herbicide Orange
Onboard the M/T Vulcanus. EPA-
600/2-78-086 (NTIS PB 281 690).
Arisman, R. K., 1979. Demonstration of
Waste Treatment Processes for the
Destruction of PCBs and PCB Sub-
stitutes in an Industrial Effluent.
Draft Report. EPA Grant S804901.
General Electric Company.
Astro Metallurgical Corp. 1977. Astrol™
Wet Oxidation Waste Treatment
Systems. Bulletins No. WT-77-1
and WT-77-3.
Crosby, D. G. and M. Y. Li. 1969.
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Kearney and D. D. Kaufman, eds.
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Biphenyls (PCBs) and PCB-Contam-
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Power Research Institute. Report
FP-1207, Volume 1.
Fuller, B., J. Gordon, and M. Kornreich.
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for the Treatment of Industrial
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February 1975.
LaPierre, R. B., E, Biron, D. Wu, L Guczi,
and W. L. Kranich. 1977. Catalytic
Hydrodechlorination of Polychlori-
nated Pesticides and Related Sub-
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262 804).
Mitchell, L. C. 1961. The Effect of Ultra-
violet Light on 141 Pesticide Chem-
icals. J. Assoc. Off. Agr. Chem. 44
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decomposition of Pesticides. Degra-
dation of Synthetic Organic Mole-
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E. J. Thorne, and F. J. laconianni.
1980. The Reaction of PCBs with
Sodium, Oxygen, and Polyethylene
Glycols. In Treatment of Hazardous
Wastes: Proceedings of the 6th
Annual Research Symposium,
Chicago, IL. EPA-600/9-80-011
(NTIS PB 80-175 094).
Rosen, J. D. 1971. Photodecomposition
of Organic Pesticides. In Organic
Compounds in Aquatic Environ-
ments. S. J. Faust and J. V. Hunter,
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NY.
Ruzo, L. O., M. J. Zabik, and R. D.
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Tucker, E. S., W. J. Litshgi, and V. M.
Mees. 1975. Migration of Polychlori-
nated Biphenyls in Soil Induced by
Percolating Water. Bulletin of Envi-
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Impact Analysis Process. Amend-
ment to the Final Environmental
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Orange Herbicide by Incineration.
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PB 284 716).
E. M. Sworzyn andD. G. Ackerman are with TRW, Inc., Environmental Division,
Redondo Beach, CA 90278.
David C. Sanchez is the EPA Project Officer (see below).
The complete report, entitled "Interim Guidelines for the Disposal/ Destruction
of PCBs and PCB Items by Non-thermal Methods," (Order No. PB 82-217 498;
Cost: $16.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
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Penalty for Private Use $300
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