PB82-217493
Interim Juidelines for the
Disposal/Destruction of PCds and PCB
iue.ns by Non-Thermal Metnods
TRW, Inc.
Redondo Beacn, CA
Prepared for
Industrial Environmenoal Researcn Lab
Research Triangle Park, NC
Apr 82
U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
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EPA-600/2-«2-069
April 1982
INTERIM GUIDELINES FOR THE
DISPOSAL/DESTRUCTION OF
PCBs AND PCB ITEMS BY
NON-THERMAL METHODS
by
E.M. Sworzyn and D.G. Ackerman
TRW Inc., Environmental Division
One Space Park
Redondo Beach, CA 90278
Contract No. 68-02-3174, Work Assignment No. 41
Task Officer: David C. Sanchez
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park, NC 27711
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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TECHNICAL REPORT DATA
(Please nod Inunctions on tht reverse before completing)
1 REPORT NO.
EPA-600/2-82-069
ORD Report
3. RECIPIENT'S ACCESSION NO.
4.T.TLEANOSUBT.TLE interim Guidelines for the Disposal/
Destruction of PCBs and PCB Items by Non-thermal
Methods
B. REPORT DATE
April 1982
6. PERFORMING ORGANIZATION CODE
7. AUTHORIS)
E.M. Sworzyn and D. G. Ackerman
8. PERFORMING ORGANIZATION REPORT NO.
9 PERFORMING ORGANIZATION NAME AND ADDRESS
TRW, Inc.
One Space Park
Redondo Beach, California 90278
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-3174, Task 41
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
00 COVERED
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTESlERL_RTp project officer is David C. Sanchez, Mail Drop 63,
919/541-2547.
16 ABSTRACT
The report is an interim resource and guideline document to help EPA re-
gional offices implement the polychlorinated biphenyl (PCB) regulations (40 JFR 761)
for using non-thermal methods of destroying/disposing of PCBs. The report descri-
bes and evaluates various alternative chemical, physical, and biological PCB remo-
val and/or destruction technologies, including: carbon adsorption; catalytic dehydro-
chlorination; chlorinolysis; sodium-based dechlorination; photolytic and microwave
plasma destruction; catalyzed wet-air oxidation; and activated sludge, trickling filter,
and other bacterial methods. The alternative technologies were evaluated using tech-
nical, regulatory, environmental impact, economic, and energy criteria. Because
the technologies investigated are in various stages of development (only sodium-based
dechlorination is available commercially), data deficiencies exist and good engineer-
ing judgment was used to supplement available quantitative information. Of the tech-
nologies evaluated, many show potential for >90% PCB destruction with minimum
environmental impact and low-to-moderate economic cost. These technologies
are: catalytic dehydrochlorination, sodium-based dechlorination, and photolytic and
microwave plasma processes.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Chlorine Aromatic
Compounds
Biphenyl
Waste Disposal
Catalysis
De hvdr ohaloge nation
Dechlorination
Sodium
Photolysis
Microwaves
Plasmas
Adsorption
Pollution Control
Stationary Sources
Polychlorinated Bi-
phenyls (PCBs)
Non-thermal Destruc-
tion
Dehvdrochlorination
13B
07C
07D
07A
07E
20N
201
14G
18 DISTRIBUTION STATEMENT
Release to Public
19 SECURITY CLASS (This Report}
Unclassified
21. NO. OF PAGES
177
20 SECURITY CLASS (Thu page)
Unclassified
22. PRICE
EPA Form 2220-1 (»-73)
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, Research Triangle Park, NC, and the Office of Toxic Substances,
U.S. Environmental Protection Agency and approved for publication. The con-
tents do not necessarily reflect the views and policies of the U.S. Environ-
mental Protection Agency, nor does mention of trade names or commercial pro-
ducts constitute endorsement or recommendation for use.
11
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ABSTRACT
This report is an interim resource and guideline document intended to
aid U.S. Environmental Protection Agency regional offices in implementing the
PCB Regulations (40 CFR 761) with regard to the use of non-thermal methods
for the destruction/disposal of PCBs.
The interim report provides descriptions and evaluates various alter-
native chemical, physical, and biological PCB removal and/or destruction
technologies, including carbon adsorption, catalytic dehydrochlorination,
chlorinolysis, sodium based dechlorinations, photolytic and microwave plasma
destructions, 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 requirements
criteria. Because the technologies investigated are at various stages of
development (only the sodium based dechlorination processes are now commer-
cially available) data deficiencies exist, and good engineering judgement was
used to supplement available quantitative information.
Of the technologies evaluated, numerous show the potential for greater
than 90% PCB destruction with minimum environmental impacts and low to moderate
economic costs. These technologies are catalytic dehydrochlorination, sodium-
based dechlorinations, microwave plasma, and photolytic processes.
This report was submitted by TRW Inc., Environmental Division in
fulfillment of EPA Contract No. 68-02-3174, Work Assignment No. 41. This
report covers the period 16 September 1980 through 19 December 1980; all work
was completed as of 17 July 1981.
m
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CONTENTS
Abstract iii
Figures viii
Tables ix
1. Introduction 1
1.1 Background 1
1.2 The Problem 2
1.3 Purpose of Report 5
1.4 Scope of Report 5
2. Development of Evaluation Criteria 8
2.1 Regulatory Factors 8
2.1.1 The PCB regulations 10
2.1.2 Resource Conservation and Recovery Act (RCRA) ... 14
2.1.3 Clean Water Act 15
2.1.4 Occupational Safety and Health Act 15
2.1.5 Hazardous Materials Transportation Act 16
2.1.6 Public notification and participation 16
2.2 Technical Factors 18
2.2.1 Destruction efficiency 18
2.2.2 Facility design and operation 18
2.2.3 Physical form 18
2.2.4 Range of concentrations 20
2.2.5 Special process requirements 20
2.2.6 Restrictions on composition 20
2.2.7 State of technology 20
2.2.8 Test and evaluation .' 20
2.2.9 Scale-up implementation 21
2.3 Environmental Factors 21
2.3.1 Impacts of disposal operation 21
2.3.2 Impacts of process effluents 21
2.3.3 Potential impacts of accidents and
malfunctions 22
2.3.4 Monitoring programs 22
2.3.5 Impacts of transportation 22
2.3.6 Closure and post-closure 23
iv
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2.4 Economic Criteria 23
2.4.1 Capital costs 23
2.4.2 Operating costs 23
2.4.3 Disposal costs 23
2.a.4 Credits for products 24
2.4.5 Closure and post-closure 24
2.4.6 Regulatory costs 24
2.5 Energy Criteria 24
2.5.1 Energy debits ^ 24
2.5.2 Energy credits 2d
3. Non-Thermal Disposal Methods 25
3.1 Physicochemical Methods 25
3.1.1 Adsorption processes 25
3.1.2 Catalytic dehydrochlorination 28
3.1.3 Chlorinolysis (chlorolysis) 30
3.1.4 The Goodyear process 32
3.1.5 Microwave plasma destruction of PCBs 36
3.1.6 Ozonation processes 40
3.1.7 Photolytic processes 41
3.1.8 Reaction of PCBs with sodium-oxygen-
polyethylene glycols 43
3.1.9 The Sunohio process 44
3.1.10 Catalyzed wet air oxidation 46
3.2 Biological Methods 48
3.2.1 Activated sludge methods 48
3.2.2 Trickling filter methods 50
3.2.3 Special bacterial methods 52
4. Evaluation of Physico-Chemical Processes 55
4.1 Adsorption Processes 55
4.1.1 Technical factors 55
4.1.2 Environmental factors 60
4.1.3 Economic factors 62
4.1.4 Energy factors 65
4.2 Catalytic Dehydrochlorination 65
4.2.1 Technical factors 65
4.2.2 Environmental factors 69
4.2.3 Economic factors 70
4.2.4 Energy factors 70
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4.3 Chlorinolysis 70
4.3.1 Technical factors 70
4.3.2 Environmental factors 73
4.3.3 Economic factors 75
4.3.4 Energy factors 75
4.4 The Goodyear Process 77
4.4.1 Technical factors 77
4.4.2 Environmental factors 81
4.4.3 Economic factors 82
4.4.4 Energy factors 83
4.5 Microwave Plasma 83
4.5.1 Technical factors 83
4.5.2 Environmental factors 86
4.5.3 Economic factors 87
4.5.4 Energy factors 88
4.6 Ozonation Processes 88
4.6.1 Technical factors 88
4.6.2 Environmental factors 91
4.6.3 Economic factors 92
4.6.4 Energy factors 93
4.7 Photolytic Processes 93
A.7.1 Technical factors 93
4.7.2 Environmental factors 97
4.7.3 Economic factors 98
4.7.4 Energy factors 98
4.8 Reaction of PCBs with Sodium, Oxygen, and
Polyethylene Glycols 98
4.8.1 Technical factors 98
4.8.2 Environmental factors 101
4.8.3 Economic factors 102
4.8.4 Energy factors 102
4.9 The Sunohio Process 103
4.9.1 Technical factors 103
4.9.2 Environmental factors 107
4.9.3 Economic factors 109
4.9.4 Energy factors 109
4.10 Wet Air Oxidation 109
4.10.1 Technical factors 109
4.10.2 Environmental factors 115
4.10.3 Economic factors 116
4.10.4 Energy factors 117
VI
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5. Evaluation of Biological Processes 118
5.1 Activated Sludge Methods 118
5.1.1 Technical factors 118
5.1.2 Environmental factors 122
5.1.3 Economic factors 125
5.1.4 Energy factors 128
5.2 Trickling Filter Methods 128
5.2.1 Technical factors 128
5.2.2 Environmental factors 132
5.2.3 Economic factors 133
5.2.4 Energy factors 136
5.3 Special Bacterial Methods 136
6. Comparison of Thermal and Non-Thermal Methods 137
7. Approval Process for Alternative PCB Disposal Methods 142
7.1 Introduction 142
7.2 Evaluation of Exemption Request and Initial Report .... 143
7.3 Evaluation of a Trial Burn Plan 145
7.3.1 Operational data 146
7.3.2 Monitoring, sampling, and analysis 146
7.4 Evaluation of Trial Burn Data 146
References 149
Appendix
A. Recommended Test Methods 154
vn
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FIGURES
Number Page
1 Disposal requirements for PCBs and PCB Items 6
2 Schematic diagram of a generalized carbon adsorption
system incorporating thermal regeneration of the carbon .... 26
3 Schematic flow diagram for hydrodechlorination process 29
4 Experimental reaction process for three chlorinated
hazardous materials 31
5 Schematic diagram of the Hoechst AG Chlorolysis process .... 33
6 Amount of reagent versus PCB concentration used in
Goodyear process 35
7 Schematic of Goodyear process 37
8 Schematic of microwave plasma system 38
9 Quartz mesh basket within microwave plasma reactor 39
10 Schematic for ozonation/UV irradiation apparatus 42
11 Process schematic for PCB destruction by catalyzed wet
air oxidation 49
12 Activated sludge process: flow diagram 51
13 High rate trickling filter flow diagram 53
I4 Flow chart for approval process for non-thermal methods .... 144
viii
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TABLES
Number Page
1 Federal Laws/Regulations Pertaining to PCBs 9
2 Explicit and Implied PCB Emission Limits from Thermal
Destruction Processes 19
3 Summary of Microwave Oxygen Plasma Reactions 40
4 Summary of Capital Costs for Carbon Adsorption 63
5 Summary of First Year Operating and Maintenance Costs for
Carbon Adsorption 64
6 Operating and Financial Data for a Chrloinolysis Facility
Processing 25,000 MT/YR of Organochlorine Waste 74
7 Summary of Capital Costs for Activated Sludge 126
8 Summary of First Year Operating and Maintenance Costs for
Activated Sludge 127
9 Summary of Capital Costs for Trickling Filter Process 134
10 Summary of First Year Operating and Maintenance Costs for
Trickling Filter Process 137
11 Technical Environmental and Economic Comparison of Thermal
and Non-Thermal PCB Destruction/Conversion Methods 139
12 Types of Data from Tests in Lieu of a Trial Burn 147
ix
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1. INTRODUCTION
1.1 BACKGROUND
Polychlorinated biphenyls (PCBs) are derivatives of the compound
biphenyl in which from one to ten of the hydrogens have been replaced with
chlorine atoms. Because they are chlorinated and aromatic, PCBs are char-
acterized by exceptionally high chemical and thermal stability. They are
of moderate to low volatility (decreases with increasing chlorine content),
are relatively non-flammable, stable to oxidation at elevated temperatures,
and have excellent electrical insulating characteristics. PCBs are insoluble
in water, are soluble in most common organic solvents, and are relatively
non-hygroscopic.
PCBs are not naturally occurring. They are synthesized, and PCBs syn-
thesized for commercial use are mixtures of various isomers. Although most
individual PCB isomers are solids at room temperature, the mixtures are
liquid and vary in consistency from mobile oils, to viscous fluids, to sticky
resins. There are 209 possible PCB isomers, ranging from three monochloro
isomers to one decachloro isomer (Hutzinger, et al., 1974). The commercial
mixtures are very complex. Sissons and Welti (1970) identified 69 isomers
in Aroclor 1254, a commercial mixture produced by Monsanto. The complexity
of these mixtures makes the tasks of sampling and analysis difficult.
Monsanto was the major U.S. manufacturer of PCBs (Fuller, et al., 1976),
and their trade mark was Aroclor. Each Aroclor mixture is named with a four
digit number in which the first two digits, 12, indicate biphenyl as the
percent compound, and the last two digits give the approximate weight percent
of chlorine in the mixture. In the example above, the digits "54" in Aroclor
1254 indicate approximate 54 weight percent chlorine. Trademarks of other
manufacturers and/or processors (world wide) are: Chlorextol, Allis-Chalmers,
USA; Clophen, Farben Fabriken Bayer, Germany; Dykanol, Federal Pacific Electric
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Co., USA; Fenclor, Caffaro S.P.A., Italy; Inerteen, Westinghouse Electric
Corp., USA; Kanechlor, Kanegafuchi Chemical Industry Co., Japan; Noflamol,
Wagner Electric Co., USA; Phenoclor and Pyralene, Prodlec, France; Pyranol,
General Electric Co., USA; Santotherm, Mitsubishi-Monsanto, Japan; and
Therminol, Monsanto, USA.
1.2 THE PROBLEM
There are three aspects of the PCB problem: their persistence, ubiqui-
tousness, and health effects. The excellent chemical and thermal stability
characteristics of PCBs made them quite useful in numerous commercial appli-
cations, particularly dielectric fluids in capacitors and transformers, but
also in heat transfer and hydraulic systems, pigments, plasticizers, carbon-
less copying paper, electromagnets, components of cutting oils, and other
uses. Their wide use and a lack of recognition of their hazards have led to
PCBs being ubiquitously distributed world-wide in all compartments of the en-
vironment (Fuller, et al., 1976). Highest concentrations are typically
found in industrialized areas, but PCBs are found in air, water, soil, and
marine samples in remote, unindustrialized areas. Experimental evidence
summarized by Fuller, et al., (1976), indicates that atmospheric transport
is the major means by which PCBs have been so widely dispersed.
The second aspect of the problem is the large amount of PCBs produced,
disposed of, and still in service. Fuller, et al., (1976), estimated that
over 400,000 metric tons (mt) were sold domestically in the U.S. during the
period 1957-1974. Nisbet and Sarofim (1972) estimated that cumulative sales
of PCBs in North America amounted to 450,000 mt from 1930 to 1970 and that
an estimated 354,000 mt had been released to the environment. Thus, as of
1970, some 96,000 metric tons are estimated to have been in service. Esti-
mated domestic sales from 1971 through 1974 were 60,000 mt (Fuller, et al.,
1976). Assuming no loss of this latter production (note that in 1972
Monsanto restricted sales to long-lived capacitor and transformer uses), it
is estimated that 156,000 (96,000 + 60,000) metric tons of PCBs may still
be in service. The Electric Power Research Institute estimates that a mini-
mum of 121,400 mt of PCBs in utility capacitors exists and will require
disposal over the next 40 years (EPRI 1979a). EPA (.1976) estimated that
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60 percent of the total production of 568,000 mt or 341,000 metric tons are
still in service.
As noted above, Nisbet and Sarofim (1972) estimated that from 1930 to
1970, an estimated 354,000 metric tons of PCBs were released to the environ-
ment, distributed as follows:
o Air - 27,000 metric tons
9 Fresh and coastal waters - 54,000 metric tons
o Dumps and landfills - 270,000 metric tons
EPA (1976) estimated that, up to and including 1975, between 136,000 and
181,000 metric tons of PCBs had entered the environment. While the estimates
above vary, there is no question that large amounts of PCBs have been both
introduced into the environment and await disposal.
The third aspect of the problem is that they are known to cause a variety
of adverse health effects in humans, animals, and other organisms. The toxi-
cology literature on PCBs has been summarized by Fuller, et al., 1976;
Kornreich, et al., 1976; and EPA 1979. PCBs are poorly metabolized and tend
to accumulate in organisms, particularly in body fat and lipid-rich organs
and tissues. PCBs bioaccumulate and biomagm'fy. PCBs appear to have caused
malignant and benign tumors in rats and mice. There are limited human epide-
miological data, but excess carcinogenic effects have been observed in
several large groups of persons exposed to PCBs. Several studies in labora-
tory animals have shown that PCBs cause fetal resorption, birth defects, and
high offspring mortality rates at levels of 1-5 mg/kg body weight. There is
also evidence that PCBs produce immuno-suppressive effects in laboratory
animals.
Adverse effects observed in laboratory animals also occur in wild ani-
mals. Effects noted in mink fed PCB-contaminated fish included reproduc-
tive failure, reduced weight gain, increased mortality, and enlargement of
liver, kidneys, and heart. PCBs are extremely toxic to several species of
aquatic invertebrates and fish. Aroclor 1254 is toxic to several shrimp
species at levels of about 1 ppb. Increased mortality of sheepshead min-
nows was observed in water containing 0.16 ppb of Aroclor 1254. Concentrations
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of Aroclors 1242, 1016, and 1254 as low as 0.1 ppb have been demonstrated to
depress photosynthetic activity in phytoplankton.
The realization of the widespread distribution of PCBs in the environ-
ment and growing knowledge of their hazards led Monsanto in 1972 voluntarily
to restrict sales of PCBs to the manufacture of electrical transformers and
capacitors. Monsanto ceased all production in 1977.
Growing evidence of the oroblem of PCB contamination and disposal led
to the inclusion of Section 6(e) in the Toxic Substances Control Act (TSCA)
of 1976. Section 6(e) would require the eventual elimination of the use of
PCBs in the United States.
Section 6(e) of TSCA required EPA to regulate the marking and disposal
of PCBs in use. It provided for a ban on the manufacture and use of PCBs in
other than a totally enclosed manner by 1 January 1978, a complete ban on
manufacture by 2 July 1979, and a complete ban on distribution in commerce
and processing by 1 July 1979. The latter bans included activities conducted
in a totally enclosed manner. EPA was, however, authorized to grant excep-
tions to the ban rules under certain conditions. Regulatory implementation
of Section 6(e) is summarized in EPA, 1979.
On 31 May 1979, (44 FR 31514) EPA promulgated the final rule, Polychlori-
nated Biphenyls (PCBs) Manufacturing, Processing, Distribution in Commerce,
and Use Prohibitions (PCB Regulations). The PCB Regulations: 1) prohibit
all manufacturing of PCBs after 2 July 1979; 2) prohibit processing, distri-
bution in commerce, and use of PCBs except in a totally enclosed manner after
1 July 1979; and 3) authorize certain exemptions. The PCB Regulations do not
require removal of PCBs and PCB Items from service and disposal earlier than
would normally be required. But, when PCBs and PCB Items are removed from
service, disposal must be in acceptance with the PCB Regulations which apply
to any substance, mixture, or item containing greater than 50 ppm PCBs.
The Electric Power Research Institute concludes that there will be a
shortfall of utility waste PCB disposal capacity (landfill and incinerator)
in most EPA regions after 1 January 1980. While utilities apparently have
the majority of PCB production still in service, there are numerous other
commercial and industrial sectors also having PCBs still in service. Thus,
4
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there is a disposal problem, and this resource document was prepared, in
part, to help ameliorate this disposal problem by providing implementation
guidance and enhancing the review, approval, and permitting of alternative
disposal methods contemplated by the PCB Regulations.
1.3 PURPOSE OF REPORT
This report is a resource and interim guidelines document. It is in-
tended to aid EPA Regional Offices in evaluating facilities for which owners/
operators have applied for approval for disposal/destruction of PCBs by
"other approved methods", i.e., methods other than those for which the PCB
Regulations give technical guidelines. To achieve this purpose, this report
provides guidance in:
9 Interpreting those portions of the PCB Regulations providing
for thermal destruction
Interpreting those portions of the PCB Regulations providing
for disposal by means other than thermal destruction
0 Establishing criteria for evaluating alternate disposal
technologies and for evaluating the consistency of alterna-
tive disposal operations with the PCB Regulations
o Facilitating coordinated and comprehensive Agency review of
PCB disposal operations
1.4 SCOPE OF REPORT
The PCB Regulations provide for disposal of PCB and PCB Items by:
Incineration in Annex I incinerators (more specifically, in
those incinerators meeting the requirements of Annex I)
Incineration in high efficiency boilers
o Landfilling in Annex II chemical waste landfills
Figure 1 illustrates the allowable disposal methods. The PCB Regulations,
Section 761.10(e), also provide for use of disposal/destruction technologies
other than those listed above, provided certain requirements are met.
This interim guidelines document applies solely to disposal/destruction
of PCBs by means other than Annex I incinerators or high efficiency boilers,
Annex II chemical waste landfills, or as municipal solid waste.
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WASTE CHARACTERIZATION
DISPOSAL REQUIREMENTS
PCS ARTICLES
PCB CONTAINERS
. MINERAL OIL DIELECTRIC FLUIDS
FROM PCB TRANSFORMERS
> THOSE ANALYZING > 500PPM PCB
. MINERAL OIL DIELECTRIC FLUIDS
FROM PCB CONTAMINATED
TRANSFORMERS
' THOSE ANALYZING 60 - SOD PPM PCB
PCB LIQUID WASTES OTHER THAN
MINERAL OIL DIELECTRIC FLUID
THOSt ANALYZING > 600PPM PCB
' THOSE ANALYZING 50-500 PPM PCB
NON LIQUID PCB WASTES
(i g. CONTAMINATED
MATERIALS FROM SPILLS)
DREDGED MATERIALS AND
MUNICIPAL SEWAGE
TREATMENT SLUDGES
CONTAINING PCBl
TRANSFORMERS
PCB TRANSFORMERS
PCB CONTAMINATED TRANSFORMERS
PCB CAPACITORS
PCB HYDRAULIC MACHINES
OTHER PCB ARTICLES
> THOSE CONTAINING > 1000 PPM PCB
THOSE CONTAINING < 1000 PPM PCB
THOSE CONTAINING PCB FLUIDS
' THOSE NOT CONTAINING PCB FLUIDS
THOSE USED TO CONTAIN ONLY PCBl -
AT A CONCENTRATION < 500 PPM
OTHER PCB CONTAINERS
(I) ANNEX I INCINERATOR IS DEFINED AT 40CFR 761 40.
(21 REQUIREMENTS FOR OTHER APPROVED INCINERATORS ARE DEFINED AT 40CFR 761 10 III
(31 ANNEX II CHEMICAL WASTE LANDFILLS ARE DESCRIBED AT 40CFH 17641 ANNEX II DISPOSAL IS PERMITTED IF THE PCB WASTE
ANALYSES LESS THAN 500 PPM PBC AND IS NOT IGNITABLE AS PER 40 CFR PART 761 41 (b) (8) (ml
14) DISPOSAL OF CONTAINERIZED CAPACITORS IN ANNEX II LANDFILLS IS PERMITTED UNTIL MARCH I. IBBI THEREAFTER ONLY ANNEX I
INCINERATION IS PERMITTED
ANNEX I INCINERATOR '"
ANNEX (INCINERATOR
HIGH EFFICIENCY BOILER (40CFR76I 10 Id) 12) (mil
OTHER APPROVED INCINERATOR121
ANNEX II CHEMICAL WASTE LANDFILL1'
ANNEX I INCINERATOR
ANNEX I INCINERATOR
HIGH EFFICIENCY BOILER 140 CFR 761 10l.il (3) dull
OTHER APPROVED INCINERATOR
ANNEX II CHEMICAL WASTE LANDFILL
ANNEX I INCINERATOR
ANNEX II CHEMICAL WASTE LANDFILL
ANNEX I INCINERATOR
ANNEX II CHEMICAL WASTE I ANDFILL
OTHER APPROVED DISPOSAL METHOD
140 CFR 7GI 10 (I) (SI (ml)
ANNEX I INCINERATOR
DRAINED AND RINSED TRANSFORMEHS MAY BE DISPOSED
OF IN ANNEX II CHEMICAL WASTE LANDFILL
. DISPOSAL OF DRAINED TRANSFORMEHS
IS NOT REGULATED
ANNEX I INCINERATOR I4)
DRAINED AND RINSED MACHINES MAY BE DISPOSED OF
AS MUNICIPAL SOLID WASTE OR SALVAGED
DRAINED MACHINES MAY HE DISPOSED OF AS
MUNICIPAL SOLID WASTt OR SALVAGED
. DRAINED MACHINES MAY BE DISPOSED OF
PER ANNEX I OR ANNEX II
ANNEX I INCINERATOR
> ANNEX II CHEMICAL WASTE LANDFILL
AS MUNICIPAL SOLID WASTE PROVIDED ANY LIQUID
PCOl ARE DRAINED PRIOR TO DISPOSAL
ANNEX I INCINERATOR
. ANNEX II PROVIDED ANY LIQUID PCBl ARE
DRAINED PRIOR TO DISPOSAL
DECONTAMINATE PER ANNEX IV
Figure 1. Disposal requirements for PCBs and PCB Items.
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Chapter 2 of this report develops criteria for evaluating alternative
technologies. Chapter 3 describes alternative physiochemical and biological
disposal technologies. Chapters 4 and 5 present, evaluations of alternative
physicochemical and biological disposal methods, respectively. Chapter 6
presents a comoarison of thermal and non-thermal means of disposal.
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2. DEVELOPMENT OF EVALUATION CRITERIA
Chapter 2 will develop and describe criteria for evaluating non-thermal
PCB disposal processes. The term "non-thermal" is used in the sense that it
refers to disposal processes that do not rely on combustion to destroy PCBs.
Guidelines for evaluating combustion processes, i.e., Annex I incinerators
and high efficiency boilers, are described in Ackerman, et al., (1980).
The evaluation criteria are grouped into five general categories, each
of which is described in subsequent sections. These categories are:
Regulatory factors
Technical factors
t Environmental factors
Economic factors
Energy factors
Each category must be considered in an overall evaluation although with cogni-
zance that the regulatory factors category, especially regulatory requirements,
is the most important one. Within a given category, individual evaluation
criteria must be considered.
This chapter develops generic evaluation criteria, that is, criteria
independent of specific non-thermal disposal practices. The purpose of this
approach is to permit Regional Offices to make relative evaluations of various
non-thermal disposal practices.
2.1 REGULATORY FACTORS
The siting and operation of a non-thermal PCB disposal facility must
comply with applicable Federal, State, and local regulations. Table 1 is
an overview of the most pertinent Federal statutes and regulations. Subse-
quent sections describe pertinent Federal regulations.
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TABLE 1. FEDERAL LAWS/REGULATIONS PERTAINING TO PCBs
Federal Statute
Federal Regulation
Toxic Substances Control Act (TSCA)
Clean Water Act (CWA)
Clean Water Act
Clear Air Act (CAA)
Resource Conservation & Recovery Act (RCRA)
Williams-Steiger Occupational Safety (OSHA)
& Health Act
Hazardous Materials Transportation Act (HMTA)
EPA, 40 CFR 761, Polychlorinated Biphenyls
(PCBs) Manufacturing, Processing, Distribution
in Commerce, and Use Prohibitions
EPA, 40 CFR 129, Toxic Pollutant Effluent
Standards
EPA, 40 CFR 116, Designation of Hazardous
Substances
EPA, 40 CFR 51 & 52, Prevention of Significant
Air Quality Deterioration
EPA, 40 CFR 122-124 and 260-265, Hazardous
Waste Guidelines and Regulations
OSHA, 29 CFR 1910, OSHA Safety and Health
Standards
DOT, 49 CFR 171-177, Transportation of Hazardous
Waste Materials
EPA, Proposed Policy on Public Participation,
45 FR 28912
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2.1.1 The PCB Regulations
Section 761.10 of the PCB Regulations specifies PCB disposal require-
ments. As shown in Figure 1, disposal of PCBs and PCB Items must be accom-
plished as follows:
e Mineral oil dielectric fluid from PCB-Contaminated Transformers
containing 50 ppm or greater but less than 500 ppm PCBs, dis-
posal through use of
- Annex I incinerator
- Annex II chemical waste landfill
- High efficiency boiler
- Other approved method
0 Liquids other than mineral oil dielectric fluids containing
50 ppm or greater but less than 500 ppm PCBs, disposal through
use of
- Annex I incinerator
- Annex II chemical waste landfill
- High efficiency boiler
- Other approved method
Non-liquid PCBs in the form of contaminated soil, rags, or other
debris, disposal through use of
- Annex I incinerator
- Annex II chemical waste landfill
- Other approved method
Dredged materials and municipal sewage treatment sludges that
contain PCBs, disposal through use of
- Annex I incinerator
- Annex II chemical waste landfill
- Other approved method
Section 761.10(e) provides for alternate disposal methods for PCBs or
PCB Items that must be incinerated:
Any person who is required to incinerate any PCBs and PCB Items
under this subpart and who can demonstrate that an alternative
method of destroying PCBs and PCB Items exists and that this
alternative method can achieve a level of performance equivalent
10
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to Annex I incinerators or high efficiency boilers are provided
in Sections 761.10(a)(2)(iv) and 761.10(a)(3)(iv) may submit a
written request to the Regional Administrator for an exemption
from the incineration requirements of Annex I. The applicant
must show that his method of destroying PCBs will not present an
unreasonable risk of injury to health or the environment. On
the basis of such information and any available information, the
Regional Administrator may, in his discretion, approve the use of
the alternate if he finds that the alternate disposal method pro-
vides PCB destruction equivalent to disposal in an Annex I incin-
erator and will not present an unreasonable risk of injury to
health or the environment. Any approval must be stated in writing
and may contain such conditions and provisions as the Regional
Administrator deems appropriate. The persons to whom such a waiver
is issued must comply with all limitations contained in such deter-
mination.
Thus, the Regional Administrator must be able to evaluate whether the
alternative system provides PCB destruction "equivalent" to Annex I incinera-
tion and whether the alternative will not present an unreasonable risk of
injury to health or the environment before he issues an approval under this
authority (761.10(e)). The key word in the regulation is "equivalent". The
use of "equivalent" implies consideration of a variety of factors. The word
"equal" is specifically not used in order to allow Regional Offices to use
discretion in approving alternative methods.
The primary basis for evaluating an alternative method for PCB disposal
is its performance relative to thermal methods. However, relative performance
is not the only basis because Section 761.10(e) does not specify performance
criteria. The Preamble to the PCB Regulations expresses EPA's expectation
that Annex I incinerators will achieve destruction efficiencies of 99.9999
percent and high efficiency boilers would achieve destruction efficiencies
of 99.9 percent or greater. These percentages provide general guidance as
to expected destruction efficiencies. However, the use of flexible language
in the rule rather than specific destruction efficiency values indicates
that destruction efficiencies is not the only factor to be considered in de-
termining equivalence.
The use of flexible language is based on several considerations rele-
vant to evaluating alternative destruction/disposal methods:
11
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The PCB Regulations use the term "destruction efficiency as a
measure of the difference between the amount of PCBs fed to
a combustion system and the amount emitted to the air. This
definition is relevant to the evaluation of boilers and in-
cinerators but is irrelevant to the evaluation of a chemical
process that has no air emissions.
e Sampling and analysis methods are subject to technical limi-
tations that could cause an apparent failure to meet a specific
"destruction efficiency" requirement.
9 Treatment and control technologies for process effluent streams
from potential disposal technologies are not equally well
developed.
Sampling and analysis methodologies are both sciences and arts. They
are sciences in that there is a body of validated methods for sampling and
analysis of organic compounds, including PCBs. They are arts in that no one
technique is optimum for sampling all streams or analyzing all samples. Thus,
mandating a minimum acceptable destruction efficiency might: 1) give rise to
situations where sampling and analysis techniques would be inadequate to
demonstrate the required destruction efficiency, 2) cause delays and increased
expense in modifying sampling and analysis methods for particular sites or
samples, and 3) give rise to difficulties in comparing the effectiveness of
different incinerators when different sampling and analysis methods were used.
The most difficult process stream to control is the stack gas because
it is the most voluminous of the three generic streams and because none of
the standard pollution control devices are effective in controlling organic
vapor emissions. The PCB Regulations set a limit on maximum PCB emissions
to the air from the stack gas (1 mg PCBs per kg of PCBs fed) while burning
non-liquid PCBs (761.40(b)(l)). No limit was set for stack gas emissions
during incineration of liquid PCBs. However, non-liquid PCBs are typically
more difficult to incinerate than liquid PCBs, so that there is a higher
probability of greater stack gas emissions of PCBs during incineration of
non-liquid PCBs. Thus, an Annex I incinerator that can achieve stack gas
emissions of PCBs of less than 1 mg per kg fed while burning non-liquid PCBs
has a high probability of producing considerably lower PCB emissions while
burning liquid PCBs.
The scrubber effluent is easier to control than the stack gas because
12
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it is less voluminous, it is a liquid rather than a gas, and because there
are treatment methods effective at removing organic compounds. Further,
because the scrubber is downstream of the combustion chamber(s), the scrub-
ber solution comes into contact with only trace or undetectable levels of
unburned PCBs. An explicit limit on the PCB content of the scrubber effluent
is not given in the PCB Regulations. However, it is required (761.40(a)(9))
that the scrubber effluent be monitored and that it comply with applicable
effluent or pretreatment standards (National Pollutant Discharge Elimination
System permits) and any other state and Federal laws and regulations. Thus,
other regulatory schemes set limits on PCB emissions in liquid process streams
to the environment from Annex I incinerators.
If present,the solid residue effluent stream from an incinerator is the
easiest to control because it is solid and the least voluminous. There-
fore, no explicit limits on the PCB content of the solid residue streams is
given, and there is no reference to any applicable regulatory criteria.
However, it is a reasonable inference that the PCB Regulations govern disposal
of this type of stream. Thus, if the solid residue stream contains less than
50 ppm PCBs, its disposal is not governed by the PCB Regulations. Conversely,
if the solid residue stream contains 50 ppm or greater PCBs, its disposal is
governed by the PCB Regulations: that is, disposal in an Annex I incinerator,
Annex II chemical waste landfill, or other approved method.
A summary of the performance requirements for an Annex I incinerator
(Section 761.40) follows:
Gaseous effluent stream - 1 mg PCBs out per kg PCBs fed for non-
liquid PCBs or 99.9999 percent gas phase destruction efficiency.
A gas phase destruction efficiency requirement of 99.9999 percent
while burning liquid PCBs is implied.
9 Liquid effluent stream - As stated earlier, no explicit emission
levels are given, but emissions of treated scrubber effluent
from the site must conform to other Federal/State regulations,
chiefly National Pollution Discharge Elimination System (NPDES)
permits. Several relevant criteria are:
_g
- Protection of freshwater aquatic life: 1.5 ng/1 (ng = 10 g)
as a 24=hour average and a not to exceed value of 6.2 ug/1
(yg=10"&g) (EPA, 1978)
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- Protection of marine aquatic life: 24 ng/1 as a 24-hour
average and a not to exceed value of 0.2 ug/l (EPA, 1978)
- Criteria for PCBs in navigable waters: 1 ug/1 (EPA, 1977a)
- Discharges of PCBs from manufacturers of PCBs, PCB capacitors,
or PCB transformers - zero discharge (EPA, 1977a)
o Solid effluent stream - as stated earlier, no explicit emission
levels are given, but it is inferred that the PCB Regulation
applies to disposal of this stream. Thus, if the PCB content
is below 50 ppm, disposal of incinerator solids is not regulated.
If the content is above 50 ppm, disposal must be accomplished by
Annex I incinerator, Annex II chemical waste landfill, or other
approved methods.
Certain of the Annex I incinerator technical requirements, such as tem-
perature; residence time; and stack gas 02, CO, NO , and C02 are not perti-
nent to alternative disposal methods. Other requirements, such as control of
HC1, total particulate matter, feed rate measurement, recordkeeping, storage,
and contingency planning are pertinent. These are discussed in Chapter 7,
which describes the approval process.
Because an alternative PCB destruction/disposal method must meet the re-
quirements for either Annex I incinerators or high efficiency boilers, it is
probable that most alternative methods will have to be tested for performance
in a manner equivalent to a Trial Burn in order for approval to be obtained.
It should be noted that tests in lieu of Trial Burns have been required of
two high efficiency boilers (Hall-Enos and Zelenski, 1980; and Tennessee
Eastman, 1979). Evaluations that should be performed during the approval
process are described in Chapter 7.
2.1.2 Hazardous Haste Regulations
Interim final and final Hazardous Waste Regulations promulgated pursuant
to RCRA indicate EPA's intention to incorporate the PCB Regulations into the
Phase II Hazardous Waste Regulations (45 FR 33066). The subject of integration
is being held in abeyance until Hazardous Waste Regulations are in place and
operational. It seems probable that the Hazardous Waste Regulations will
apply to PCB disposal operations, particularly those portions that establish
standards for facilities and for permits for treatment, storage, and disposal
facilities.
14
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A significant feature of the Parts 265 and 265 of the Hazardous Waste
Regulation are standards and interim status standards covering reprocessing.
If an alternative method for PCBs is a reprocessing one and if the usable
product contains less than 50 ppm of PCBs, then only the Hazardous Waste Regu-
lations concerning transportation and storage need be followed (40 CFR 261.6).
2.1.3 Clean Water Act (CWA) Regulations
Regulations pursuant to the Clean Water Act, 40 CFR 129, set toxic pollu-
tant effluent standards for PCBs. Mo discharge of PCBs is allowed (40 CFR
129.105) from manufacturers of: 1) PCBs, 2) electrical capacitors, and 3)
electrical transformers. This standard applies to both new and existing
sources. While 40 CFR 129.105 includes discharges from incineration areas in
manufacturing plants, it does not appear that the standards mandated in 40
CFR 129.105 cover commercial contract incinerator operators because the defi-
nitions of manufacturers explicitly refer to those who: 1) produce PCBs,
2) produce or assemble capacitors in which PCBs are part of the dielectric,
or 3) produce or assemble electrical transformers in which PCBs are part of
the dielectric. Parts 116 and 117 of the Act define discharges under the Act,
designate reportable quantities of PCBs spilled into waterways, and designate
reporting requirements and fines.
The Clean Water Act also mandated preparation of a National Oil and
Hazardous Substances Pollution Contingency Plan (40 CFR 1510). The final
plan was published in 45 FR 17832. The Hazardous Uaste Regulations also
require the owner/operator of a hazardous waste facility to prepare a con-
tingency plan (40 CFR 264.50) but states that the requirement can be met by
appropriate amendments to an existing plan. The Electric Power Research
Institute recently published two reports dealing with spill prevention, con-
trol, and countermeasures planning for PCBs for electric utility operators
(EPRI 1979a, 1979b). EPA has published a manual for control of hazardous
material spills (EPA 1977b).
2.1.4 Occupational Safety and Health Act Regulations
Under provisions of 29 CFR 1910.1, the OSHA 40-hour week limit for
3 3
Aroclor 1242 is 1 mg/m and 500 yg/m for Aroclor 1254. In September 1977,
the National Institute for Occupational Safety and Health recommended a
15
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time-weighted average for all PCBs of 1.0 pg/m . However, the OSHA standard
has not yet been changed.
The current time-weighted average for PCBs as established by the American
Conference of Governmental Industrial Hygienists is 1 mg/m for Aroclor 1242
and 0.5 ng/m3 for Aroclor 1254 (ACGIH, 1979).
2.1.5 Hazardous Materials Transportation Act Regulations
Under the Hazardous Materials Transportation Act, U.S. Department of
Transportation (DOT) regulations in 49 CFR 171-177 cover the transport of
hazardous waste materials. The rules place minor recordkeeping requirements
on shippers and transporters of hazardous wastes and prohibit transportation
and delivery to improper treatment, storage, or disposal sites. The Hazard-
ous Waste Regulations in 40 CFR 263 set standards for transporters of hazard-
ous wastes by adopting certain of the DOT regulations referenced above.
2.1.6 Public Notification and Participation
The PCB Regulations do not explicitly discuss public notification or
participation in the approval process. It is not an unreasonable assumption,
therefore, that it is the intent of the regulation that PCB disposal (thermal
or alternative methods) facilities should be approved by Regional Administra-
tors on their technical merit alone.
There is ample evidence of public concern about the operation and siting
of hazardous waste disposal facilities. Local support for operation of such
facilities is desirable if not essential. This section describes steps that
can be taken to inform and promote public support. It also describes some
public relations deficiencies to be avoided.
EPA's recently published prooosed policy on public participation in
Agency decision-making and rule making (45 CF 28911) offers guidance on
ensuring public participation. EPA defined five basic tasks to be performed.
These are briefly described below.
Identification. Those groups or members of the public who
may be interested in or affected by action (i.e., PCB de-
struction facility approval) should be identified. The
responsible official must develop a contact list for each
program or project.
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t Outreach. Information about a PCB approval action must be
conveyed to the public through mailings, personal communi-
cations, public service announcements, media briefings or
ads, and other means. The information must include background,
timetables, summaries of technical material, and, if possible,
a description of social, economic, and environmental conse-
quences.
t Dialog. The responsible official and interested or affected
members of the public must be able to exchange views and ex-
olore issues. The dialog may take several forms; meetings,
workshops, hearings, or correspondence. Timely dissemination
of information is crucial.
Assimilation. The results of the "outreach" and "dialog" tasks
must be assimilated into the final decision, and the responsi-
ble official must demonstrate that he has understood and con-
sidered public concerns.
Feedback. The responsible official must provide feedback to
interested parties concerning the outcome of the public's
participation. This feedback must state the action that was
taken and indicate the effect that public participation had
on the action.
Public concern caused considerable delays in performing a PCB Trial Burn
in an industrial boiler at General Motors Corporation's Chevrolet plant in
Bay City, Michigan. Zelenski et al., (1980) reported on deficiencies in the
public participation process. The single major deficiency was that in the
early stages the public was not provided with sound technical documentation
showing that the PCB burn would be safe. Specific deficiencies were:
The public was not informed of the proposed permit application
in the early planning stages.
Soecial interest groups were not informed of the proposed
permit application in the early planning stages.
Plant personnel were not informed in the early planning
stages.
Information needs of the public and special interest groups
were not adequately anticipated.
Information finally supplied was perceived as too technical.
There was a lack of communication, coordination, and clearly
defined responsibilities between participants in the permit
approval process.
Zelenski, et al., (1980) made a number of recommendations, several of
which are basically the same as may be required by EPA's proposed policy
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on oublic participation:
o Identify the concerned public and grouos
Communicate with the concerned public and groups
Develop a relationship of cooperation with the public
and groups
Determine the level of support and incorporate that in
plans for the proposed action
Consideration of the above public participation policy guidance should facili-
tate Agency permitting of alternative PCB disposal methods.
2.2 TECHNICAL FACTORS
2.2.1 Destruction Efficiency
The regulatory guidance presented in Section 2.1.1 identifies destruc-
tion efficiency as a necessary technical evaluation criterion for any alter-
native disposal method. An alternative method must "achieve a level of
performance equivalent to Annex I incinerators or high efficiency boilers"
(40 CFR 761.10(e)). Table 2 presents a summary of explicit or implied emis-
sions limits for PCBs in the three generic process effluent streams from
Annex I incinerators and high efficiency boilers.
2.2.2 Facility Design and Operation
When the PCB Regulations are incorporated into the Phase II Hazardous
Waste Regulations, it is expected that facility standards (40 CFR 264, 265)
will apply to PCB disposal facilities. Thus, a non-thermal PCB disposal
process will have to be evaluated for compliance with Hazardous Waste Regu-
lations requirements for waste receiving and storage areas, chemical analy-
sis capability, inspection schedules, security, preparedness for and pre-
vention of hazards, contingency plans, emergency procedures, manifest systems,
and recordkeeping procedures.
2.2.3 Physical Form
It is anticipated that most alternate methods will be apolied chiefly
to PCB-contaminated liquids. However, some processes may be applicable to
non-liquid PCBs or may be used in situ to decontaminate PCB Items, e.g., a
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TABLE 2. EXPLICIT AND IMPLIED PCB EMISSION LIMITS FROM THERMAL DESTRUCTION PROCESSES
Method
Process Effluent Stream
Air
Liquid
Solid
Annex I
Incinerator
1 mg/kg fed*
1.5 ng/1, 24-hr average
6.2 jjg/1, not to exceed
50 ppm
High Efficiency
Boiler
**
of PCB fed
ditto above
50 ppm*
* When burning non-liquid PCBs. Corresponds to a gas-phase destruction efficiency of
99.9999%. When burning liquid PCBs, performance is expected to be as good or better
than when burning non-liquid PCBs
+ EPA freshwater criterion (EPA 1978). Disposal of a scrubber effluent with a PCB
concentration greater than 50 ppm is regulated by the PCB Regulation; disposal of a
scrubber effluent with a PCB concentration less than 50 ppm is not. However, other
regulations would govern discharge of such a stream from the site.
# Disposal of solid residues is assumed to be governed by the PCB Regulations: below
50 ppm disposal is not governed, above 50 ppm disposal is governed.
** No explicit values are given. Destruction efficiency is considered to be at least
99.9%. Total emissions should thus be less than 0.1 percent of PCBs input. Maximum
PCB concentration in input feed is 500 ppm.
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PCB Transformer. For a non-thermal process that is apolied to non-liquids,
the size of the solids may be a factor. Shredding and/or hammermilling may
be necessary.
2.2.4 Range of Concentrations
The range of PCB concentrations that the alternate process can handle
is important. A non-thermal process treating liquid containing greater than
500 ppm PCBs must be evaluated against Annex I incinerator requirements,
while a non-thermal process treating liquid containing 50 to 500 ppm PCBs may
be evaluated against high efficiency boiler requirements.
2.2.5 Special Process Requirements
Some alternate methods may require processing at high temperature and/
or pressure, long residence time, etc., or have special requirements for
storage, heat transfer, mass transfer, or materials of construction. Each
of these engineering factors must be evaluated. The possibility of formation
of toxic by-products must also be evaluated.
2.2.6 Restrictions on Composition
In some cases, thermal destruction of a PCB waste may be undesirable
because it contains certain constituents (e.g., metals such as As or Hg)
which might cause a hazard from the incinerator effluent streams. Similarly,
a PCB waste may contain constituents which make non-thermal disposal dis-
advantageous, e.g., a catalyst poisoned by sulfur.
2.2.7 State of Technology
The non-thermal methods described in this report are not at commercial
scale at this time and some have not been applied to PCB disposal. Thus, the
state of the technological development of each non-thermal method is assessed
and consideration is given to scale up, commercial potential, research poten-
tial , etc.
2.2.8 Test and Evaluation
It was noted in Section 2.1.1 that, because an alternative PCB disposal
technique must meet the requirements of either Annex I incinerators or high
efficiency boilers, it is expected that testing equivalent to a Trial Burn
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will be required. (The term "equivalent" is used in the sense that testing
of emissions and destruction performance will be necessary. Not all of the
Annex I incinerator or high efficiency boiler parameters are pertinent to
alternative disposal methods.)
The facility operator should make sure to provide process instrumenta-
tion adequate to control and measure appropriate process parameters, such
as PCB input rates, pressures, temperatures, effluent stream flow rates, etc.
Appropriate test ports must be provided so that process stream samples may
be acquired.
2.2.9 Scale-Up Implementation
As a non-thermal process is taken from the research, to bench scale,
to pilot scale, to commercial scale stages of development, continuing engine-
ering design and testing are necessary. For example, some of the chemical
methods discussed in Chapter 3 generate heat during the reactions that destroy
PCBs. Removal of excess heat is easy for small scale reactors but more diffi-
cult for large scale reactors. Testing for destruction efficiency is neces-
sary to ensure that scale up has not reduced destruction efficiency.
2.3 ENVIRONMENTAL FACTORS
2.3.1 Impacts of Disposal Operation
Impacts of the overall disposal operation need to be assessed. This
assessment logically occurs prior to implementing scale up of a process to
commercial scale and thus is the responsibility of the developer of the
method. In principal, any negative impacts should be more than offset by the
advantages of having the disposal facility.
As part of evaluating a request for a waiver for an alternative process,
the Regional Administrator needs to assess environmental impacts before he
issues an approval. Subsequent paragraphs discuss criteria for assessing
environmental impacts of various parts of an overall alternative disposal
process.
2.3.2 Impacts of Process Effluents
A major factor in assessing potential environmental impacts of an
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alternative method is potential impacts of process effluent streams. Whether
the alternative process is one of destruction, conversion, or reclamation,
nrocess effluent streams must be controlled, treated, disposed of, and/or
sold. Not only residual PCB content, but also other possible constituents
(e.g., toxic organics, Teachable metals, biologicals, etc.) must be consider-
ed and dealt with in accordance with applicable regulations. Effects on air,
water, and land should be assessed.
2.3.3 Potential Impacts of Accidents and Malfunctions
As noted in Section 2.1.2, the Hazardous Waste Regulations will require
preparation of spill prevention, control, and countermeasures (SPCC) plans.
Potential impacts of accidents at a non-thermal facility should be comoared
with the ootential impacts of accidents at a thermal disposal facility.
Thermal disposal facilities are reciuired to have fail-safe orocess monitor-
ing instrumentation that shuts off PCB feed when certain orocess parameters
exceed pre-set limits. Similarly, a non-thermal disposal facility should be
eouinoed with fail-safe devices and instrumentation for monitoring critical
parameters.
2.3.4 Monitoring Programs
The Hazardous Waste Regulations will require routine inspection and
monitoring activities to ensure th?t necessary maintenance activities occur
and that PCBs and/or other potentially harmful substances do not migrate
outside of the site boundaries. Evaluation of a commercial scale non-thermal
disposal should thus consider materials of construction and architecture as
these relate to maintenance. Process effluent containment, treatment, and
disposal facilities should be evaluated with resoect to prevention of escape
of the streams from the site. Monitoring programs may include air monitoring,
groundwater monitoring, and periodic physical examination of olant personnel
(40 CFR 265, Suboart F).
2.3.5 Impacts of Transportation
In principal, the types of PCBs and PCB Items and transportation modes
would be similar for both thermal and non-thermal disposal facilities. If
there is a significant difference, then potential impacts of transportation
22
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should be evaluated. Regulations governing transportation of hazardous waste
are found in 49 CFR Parts 171-179.
2.3.6 Closure and Post-Closure
The Hazardous Waste Regulations propose to require closure and oost-
closure plans. The technical aspects of such plans should be evaluated in
context with 40 CFR 254, Subpart G.
2.4 ECONOMIC FACTORS
The PCB Regulations do not give EPA regulatory authority with respect
to economic factors. Consequently, economic factors should have no bearing
in an approval. However, a discussion of economic factors is included here
out of general interest but not for regulatory purposes. Economic factors
will play a significant role in the commercialization and operation of a
PCB disposal facility, whether thermal or non-thermal. An uneconomic process,
no matter how attractive technically, is not likely to be commercialized.
The decision to commercialize a process obviously lies with the developer.
2.4.1 Capital Costs
Capital costs for facility construction or modification include costs
of land, equipment, structural material, labor, pollution control equipment,
process effluent treatment facilities, and money.
2.4.2 Operating Costs
Costs of labor, utilities, reagents, transportation, disposal, depre-
ciation, etc. are components of operating costs. Operating costs in terms
of cost per pound of waste and/or cost per pound of PCBs are important cri-
teria in the decision to start and continue operations. If there is a sale-
able product resulting from a non-thermal disposal alternative, a reduction
in operating costs results.
2.4.3 Disposal Costs
An important component of operating and capital costs is disposal of
process wastes after necessary on-site treatment.
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2.4.4 Credits for Products
Recycle/reclamation processes will produce ootentially useful and sale-
able products. The resulting revenue reduces operating costs and makes pro-
cess economics more attractive.
2.4.5 Closure and Post-Closure
Costs for closure and post-closure monitoring and maintenance must be
assessed as part of overall process economics.
2.4.6 Regulatory Costs
Approval of an alternative PCB disposal facility may result in greater
costs than for thermal disposal because of increased regulatory evaluation,
testing, and notification requirements.
2.5 ENERGY FACTORS
2.5.1 Energy Debits
Thermal disposal facilities are purely destructive. Depending on the
nature of the PCB waste to be destroyed, energy usage may range from low
(high heat content waste) to high (low heat content waste). Incinerators
generally blend a high heat content waste with a low heat content waste in
order to reduce energy costs.
If a non-thermal process is operated primarily for PCB disposal, energy
usage should be assessed in comparison with energy requirements for a thermal
disposal facility of equal performance capability.
2.5.2 Energy Credits
If a non-thermal process produces a product that can be used for energy
oroduction or if some or all of the heat content of the waste stream is re-
covered, then an energy credit occurs. Heat recovery from hazardous waste
incinerators is not practiced in the United States although the heat content
of a PCB waste produces steam when it is burned in a high efficiency boiler.
Recycle/resource recovery processes can be attractive with respect to
energy credits. For example, a process that could economically remove/
destroy the PCBs in mineral oil dielectric fluid would lead to the saving
of millions of gallons of oil that would otherwise be incinerated.
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3. A REVIEW OF POTENTIAL MOM-THERMAL
DISPOSAL METHODS
3.1 PHYSICOCHEMICAL METHODS
This section of the report describes current research and development
of various physicochemical disposal methods for PCBs and PCS related materials.
None of these processes are "state-of-the-art". Most exist only on the lab-
oratory scale with limited data available. Many of the assumptions must be
aualitative in nature. Technical information gaps are widespread in the
literature, thus making it very difficult to present analytical data.
Specific processes covered may apply to the treatment of PCB Transformer
fluids containing >500 ppm PCBs, capacitors, other heat transfer fluids or
PCB Articles containing more than 50 ppm PCBs. Certain processes covered may
apply to aqueous systems only, while others may not have been applied to PCB
degradation or detoxification at all. These latter processes will be de-
scribed in this section and evaluated in the next section based on the possi-
bility of these processes being able to be adapted to PCB treatment.
3.1.1 Adsorption Processes
An extremely useful method for removing chlorinated hydrocarbons from
aqueous waste streams is to contact the stream with activated carbon by pass-
ing it through a vessel filled with a carbon slurry or with carbon granules.
Impurities from the aoueous streams are removed by adsorption onto the char-
coal. The complete adsorption system usually consists of a few columns used
as contactors connected to a regeneration system, as shown in Figure 2.
After a certain period of time, the carbon adsorptive capability is exceeded,
and the carbon must be regenerated. Fresh carbon is periodically added to
the system to replace that lost during regeneration and transport. A mul-
tiple hearth furnace is included in the regeneration system (Hansen and Rishel,
1979). Activated carbon has an affinity for organics, and its use for organic
25
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HI AMlVAIl |l( AitUONSI URIO
Figure 2. Schematic diagram of a generalized carbon adsorption system
incorporating thermal regeneration of the carbon (Hanson and Rishel, 1978).
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contaminant removal from wastewater is common. It is estimated that there
are over 100 large scale systems currently in use for industrial and muni-
cipal wastewater treatment (Zanitsch, 1978). Carbon adsorption is particu-
larly favorable when the solutes have a high molecular weight and low water
solubility, as is the case with dissolved PCBs. Carbon adsorption was one
of the most promising water treatment systems for removing dissolved PCBs,
as indicated in a study done by Versar Inc. in 1976 (Versar Inc., 1976). It
was found in that study that the activated carbon system was capable of reduc-
ing the concentration of PCBs in the aqueous effluent to less than 1 ppb
(Versar, Inc., 1976).
In 1976, the General Electric Capacitor Products Department installed
a system to eliminate the discharge of PCBs to the Hudson River from the
Hudson Falls and Fort Edward manufacturing sites. All wastewater discharged
from the site was treated by carbon adsorption before the discharge to the
river. This adsorption process worked extremely well for dilute aqueous
streams contaminated with PCBs (Arisman, 1979). It was found that, while the
carbon treatment system could reduce the concentration of PCBs in the aqueous
effluent to less than 1 ppb, it was not a very cost effective method. This,
coupled with carbon disposal or regeneration requirements, provided a basis
for the EPA and the General Electric Capacitor Products Department to inves-
tigate alternate treatment systems, i.e., UV-Ozonation and catalytic reduc-
tion.
Application of activated carbon adsorption processes is less common to
non-aqueous streams than to aqueous streams. However, the U.S. Air Force
(U.S. Air Force, 1976) funded studies on using activated carbon to remove a
contaminant (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) with an average
concentration of 2 ppm from Herbicide Orange, a nominally 50:50 mixture by
volume of n-butyl esters of 2,4-dichlorophenoxyacetic acid and 2,4,5-tri-
chlorophenoxyacetic acid. TCDD was reduced to 0.1 ppm or less, and the pro-
cess was considered technically and economically feasible. However, the
U.S. Air Force concluded that the technology to dispose of the TCDD-conta-
minated activated charcoal (approximately 640 tons of charcoal) did not
exist, and the Herbicide Orange stocks were instead successfully incinerated
at sea (Ackerman, et al., 1978).
27
-------
From a technical point of view, adsorption processes for removing or-
ganic compounds from liquid streams are attractive because they offer the
possibility of resource recovery, e.g., removal of PCBs from mineral oil
dielectric fluid. Adsorption processes are not destructive. They merely
reduce the contaminant concentration in the liquid stream and concentrate
the contaminant in the adsorbent. To be economical, the contaminant must be
removed from the adsorbent, so that an adsorption process applied to PCB
disposal must be coupled v/ith a second disposal/destruction process to handle
PCBs removed from the adsorbent during regeneration.
3.1.2 Catalytic Dehydrochlorination
Catalytic dehydrochlorination is based on the reaction of polychlorinated
hydrocarbons with high pressure hydrogen gas in the presence of a catalyst
(La Pierre, et al . , 1977). The reaction is:
+ xH2 RH x Cln_x + xHCl
wnere n and x are small integers.
The reasoning behind this reaction is that partially dechlorinated or
nonchlorinated compounds could be less toxic and, therefore, could be bio-
degraded more easily than highly chlorinated compounds. This process has
been directly applied to the detoxification of PCBs. A flow diagram of the
hydrodechlorination process is presented in Figure 3. This process is adap-
ted for batch operation and has been done on bench scale only.
The PCBs are batch fed into a rotary extractor. The extraction uses
hot ethanol , and the extracted material is pumped to a reaction vessel.
Sodium hydroxide in ethanol is added next to react with liberated HC1 gas
which could deactivate the catalyst and could cause corrosion problems. The
reaction vessel is kept under a pressure of 3 to 5 MPa (30 to 50 atm.) with
H2 gas.
The catalyst can be either 61 percent nickel on kieselguhr or 10 oer-
cent palladium on charcoal. The catalyst should be prereduced in hydrogen
at 643°K (1157°F) for best results. During reactor vessel discharging,
28
-------
ETHANOL LIQUID
SOLVENT
HOLDING
TANK
CONDENSER
HIGH PRESSURE
HYDROGEN
NaOH IN
ETHANOL
SOLUTION
ROTATING
DRUM
EXTRACTOR
CATALYST
RETAINER
HYDROCARBONS
CONDENSER
SOLVENT
RECOVERY
STILL
PUMP
HYDROCARBONS
NaCI
H20)
LIQUID
LIQUID
EXTRACTOR
NaCI
Figure 3. Schematic flow diagram for hydrodechlorination process
(Kranich, et al., 1977).
29
-------
catalyst particles of 0.15 to 0.30 cm diameter are retained on a stainless
steel screen. The quantity of catalyst should be 0.2 percent of the weight
of the PCBs to be dechlorinated.
Experimentally determined reaction conditions for pressure and tempera-
ture are 3 to 5 MPa (30 to 50 atm) and 373 to 393°K (671 to 707°F). Reaction
time depends on the desired degree of dechlorination for a specific compound.
According to Figure 4, about 90 percent of the chlorine may be removed from
PCBs in about 5 hours (Kranich, et al., 1977). Completion of the reaction
is determined by a decreasing demand for sodium hydroxide. After completion,
the reaction mixture is pumped to a solvent recovery still. The catalyst
particles are retained on a stainless steel screen in the reactor vessel.
Ethanol is then distilled through a bubble cap column or another type of
fractionating head and returned to the solvent holding tank. The products
consisting of hydrocarbons, incompletely dechlorinated materials, salt, and
water are v/ashed with water in a liquid-liquid extraction vessel. The hydro-
carbon materials are stored for possible usage, and the salt water is dis-
carded.
Since this process has not been scaled up, industrial data are not
available.
3.1.3 Chlorinolysis (Chlorolysis)
Chlorinolysis is an emerging process for the conversion of chlorinated
hydrocarbons. This is a vapor phase reaction in which chlorine is added to
the waste material under high pressure and low temperature or high tempera-
ture and low pressure. A catalyst is not used in the 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). Because of
corrosion and oxidation, the reactor must be composed of special materials.
Chlorination as a method of disposing of hazardous wastes was first
suggested in 1974 (Anon., 1974). Exhaustive Chlorination can be accomplish-
ed over a wide range of pressures and temperatures. Farbweke Hoeschst AG,
Frankfurt/Main, Germany, has developed a process where hydrocarbons and their
chlorinated derivatives are completely converted to carbon tetrachloride and
30
-------
1.0
0.8
Q
LU
I-
DC
UJ
O
O
uj 0.6
Z
DC
O
X
u
g 0.4
u.
O
z
o
0.2
\"l
TOXAPHENE
PCB
5 10 15
REACTION TIME, HOURS
20
Figure 4. Experimental reaction process for thre£ chlorinated
hazardous materials (Kranich, et al., 1977).
31
-------
hydrogen chloride at pressures up to 24 MPa (240 atm) and temperatures up
to 893°K (1575°F) (Krekeler et al., 1975). Figure 5 presents a flow diagram
of the Hoeschst AG chlorolysis process. Although it is not documented if
chlorolysis on PCBs has been accomplished, reaction products would be CC1,
and HC1. Organic wastes that contain sulfur, nitrogen, or phosphorous may
have ill effects on the process. For example, if sulfur in excess of 25 ppm
is contained in the feedstream, severe corrosion of the nickel tube catalytic
reactor could occur.
An extensive literature search indicates that the Hoechst Uhde process
is the only one that has some capability of handling aromatic hydrocarbon
feedstocks. The Hoechst Uhde process is the only chlorolysis process that
does not produce organochlorine residues in large quantities since all wastes
initially produced can be recycled for further degradation. A demonstration
plant producing 8,000 metric tons/year of carbon tetrachloride has been on
stream in Frankfurt, Germany, since November 1970. A commercial plant pro-
ducing 50,000 metric tons/year of carbon tetrachloride has been on stream at
the same location since 1977.
The chlorolysis plant consists of a pretreatment section for the treat-
ment of all the wastes entering the unit, a reactor section where the heated
residues are converted into HC1 and CC14, a distillation section for the
separation of reaction products, and an incineration section for the disposal
of remaining residues. An adsorption unit is used for the elimination of
waste gases containing CU gas and HC1.
3.1.4 The Goodyjear Process
The Goodyear Tire and Rubber Company has recently developed a process
(Goodyear, 1980) to degrade low levels of PCBs. Two allied approaches showed
favorable results: the catalytic hydrogenolysis of carbon-chlorine bonds
over a palladium catalyst and the cleavage of carbon-chlorine bonds by the
use of sodium or organo-sodium reagents. Both of these methods were shown
in Goodyear's laboratories to dehalogenate PCB materials from levels of 120
ppm to less than 10 ppm. The reaction with sodium or organo-sodium was
found to operate at lower temperatures and, therefore, was chosen as the pre-
ferred process.
32
-------
-10°C
HAZARDOUS
WASTE
MATERIALS
10
CO .
crc
0.1
MPa
80°C
M
aO
1
v
H
*
HCI
*-CCI,
CCI,
WASTE
REACTOR
HIGH BOILER CRUDE CCL
COLUMN
COLUMN
HCI
COLUMN
CRUDECCL
COLUMN
COCLj
CAUSTIC SCRUBBER
SEPARATOR
DRYER
Figure 5. Schematic diagram of the Hoechst AG Chlorolysis process
(Krekeler, et al., 1975).
-------
The reactions were found to be extremely fast at ambient temoerature.
Recently, Japanese researchers have successfully dechlorinated high concen-
trations of PCBs in tetrahydrofuran at 273°K (Oku, Yasufuku and Kataoka, 1978)
They claim that only 1.1 to 1.3 moles of sodium naphthalide per mole of chlo-
rine (as Cl) was needed to remove all the organic chlorine. A similar method
was also researched at the University of Waterloo, Canada (Electronic and
Engineering Times, 1979). The Goodyear research team attempted to adapt the
Japanese methods to the removal of low level (ppm) PCB contamination. It was
soon discovered that 1.1 to 1.3 molar ratios of sodium naphthalide to chlo-
rine were too low to obtain any meaningful reduction in PCB levels. As shown
in Figure 6, a 50-100 mole ratio was found to be the minimum necessary to
remove 98 percent of the PCBs from the heat transfer oil composed of 83 ppm
PCB. This reaction v/as found to proceed in less than five minutes under an
inert atmosphere. Due to procedural difficulties with the preparation of the
sodium naphthalide reagent, a new procedure for reagent preparation was
developed. 150-400 ml of either fresh or contaminated heat-transfer fluid
per gram-atom of sodium v/as used to form an extremely reactive form of sodium
containing a low surface oxide coating. This was done by heating pieces of
sodium in the heat-transfer fluid under an inert atmosphere to 423-443°K for
5-10 minutes with rapid stirring. This solution was then cooled to ambient
temperature while stirring. The sodium droplets solidified into bright
spheres. The reagent itself was next formed by the addition of the tetra-
hydrofuran-naphthalene solution to the sodium in the heat-transfer fluid
at ambient temperature. The reagent was completely formed after one hour
with gentle stirring. This method of reagent preparation was found to work
very effectively on both small and very large scales. The reagent could
next be added to a large amount of additional heat-transfer fluid. The
amount of reagent would be adjusted to give a minimum reagent/chlorine ratio
of 50 to 100. This reaction occurred rapidly at room temperature. After
about one hour, the excess reagent was quenched by adding at least a stoichio-
metric quantity of water. This quenched fluid was next stripped under vacuum
to recover tetrahydrofuran and naphthalene for possible recycling. The resi-
due was vacuum distilled again. The recovery heat-transfer fluid contained
less than 1 ppm PCB. The recovered heat-transfer fluid contained less than
34
-------
CO
tn
a.
CD
Q
100
90
80
70
60
<
? 50
cc
o
I
U
2
Q.
Q.
40
30
20
10
0
250 ml HEAT TRANSFER OIL (83 ppm PCB'S)
TREATED 2 HOURS @ 60°C WITH 2. 5,10,20 OR 30 ml
RESPECTIVELY OF 0.73 M SODIUM NAPHTHALIDE SOLUTION
25
50
75
100
125
150
MOLE RATIO Na NAPHTHALIDE/CHLORINE
Figure 6. Amount of reagent versus PCB concentration used in Goodyear
process (Goodyear Tire and Rubber Company, 1980).
-------
1 ppm PCB. The residues in the pot from the second distillation contained
non-halogenated polyphenyls, which could be safely burned, and sodium chlo-
ride.
This process has been adapted for use on a commercial scale. Material
containing 130 ppm PCBs have been reduced to less than 10 ppm. Figure 7
represents a schematic of the Goodyear Process.
3.1.5 Microwave Plasma Destruction of PCBs
Lockheed Missiles and Space Company, Palo Alto Research Laboratory
(LPARL), has developed a process to detoxify PCBs and other hazardous
materials based on microwave plasma destruction (Oberacker and Lees, 1977).
Research started on the bench scale and has been expanded to a unit which
can successfully detoxify PCBs at the rate of 0.45 to 3.2 kg/hr (1 to 7
Ib/hr). EPA has sponsored a project to demonstrate a 4.5 to 13.5 kg/hr
(10 to 30 Ib/hr) apparatus. A future goal is to develop a 40 to 50 kg/hr
(-100 Ib/hr) version.
Figures 8 and 9 are schematic diagrams of the microwave plasma unit.
The unit was built from commercially available standard glass apparatus and
electronic hardware. Two 2.5 kU power transformers provide energy at 2450
MHz to the microwave reactor. This energy is fed through wave guides and
"focused" just before entering the applicator assembly surrounding the
quartz reaction tube.
A continuous sampling gas analyzer was placed in line between the re-
actor tube outlet and the ice water cold trap to monitor the detoxification
process. An infrared spectrophotometer and a gas chromatograph were also
used for monitoring.
The PCB material was added to the system as a pure liquid. Operating
pressure was 1.3 to 13.3 kPa (10 to 100 torr). Samples of PCB material to
be detoxified were introduced through a dropping funnel. The carrier gas
was fed above the dropping funnel. The PCB material was transported by
both gravity and by the carrier gas (oxygen, oxygen-argon, or steam) through
a quartz reaction tube. The reaction products were contained in traps cool-
ed with ice water or liquid nitrogen placed between the reaction tube and
the vacuum pump.
36
-------
N2 INLET
AUTOCLAVE
AGITATOR-
SODIUM
BRICKS
1. 150-170 C
FAST
AGITATION
2. RAPID
COOLING
THF
NAPHTHALENE
RT
DISPERSING OIL
FINE SODIUM
SHOT IN OIL
DISTILLATION
UNCONTAMINATED FLUID \
NAPHTHALENE > OVERHEAD
THF '
H2O QUENCH
CONDENSED POLYAROMATICS
NACL, NAOH
RESIDUE
SODIUM
NAPHTHALIDE
REAGENT
PCB
CONTAMINATED
FLUID
STORAGE TANK
Figure 7. Schematic of Goodyear process (Goodyear Tire and Rubber
Company, 1980).
-------
PESTICIDE
DROPPING
FUNNEL
TUNING
UNIT
MICROWAVE
POWER SOURCE
MICROWAVE
APPLICATOR
TUNING UNIT
MICROWAVE
POWER SOURCE
RECIEVER \J
PLASMA
REACTOR
TUBE
MASS SPEC
TROMETER
1
I I
O 1A/A Y '
FLOW METERS
02 ALTERNATE
SUPPLY GAS SUPPLY
STOPCOCK
MANOMETER
COLD TRAP
VACUUM PUMP
THROTTLE
VALVE
COLD TRAP
Figure 8. Schematic of microwave plasma system (Bailin and Hertzler,
38
-------
LIQUID PLUS CARRIER GAS
TEFLON
NEEDLE-VALVE
STOPCOCK
CARRIER GAS
QUARTZ
REACTOR
TUBE
QUARTZ
BASKET AND
FIBERS
FIRST
PLASMA
ZONE
TRAPS AND VACUUM PUMP
Figure 9. Quartz mesh basket within microwave plasma reactor
(Bailin and Hertz!er, 1976).
39
-------
The PCB material is destroyed in the reaction tube by applying the
microwave radiation. This generates an ionized carrier gas. The microwave
induced plasma reacts with the neutral organic PCB molecules to form free
radicals which then either dissociate or react with oxygen to form simple
reaction products such as SO-, CO-, CO, O, COCl-, etc. The discharge is
usually ignited with a Tesla coil.
After the PCB material is destroyed, the reaction products which are
now vapors and any other condensible material are sent into an ice water
bath and then to a liquid nitrogen cold trap. The carrier gas then enters
the vacuum pump.
The PCBs used were of the Aroclor 1242 variety. Feed rates were from
0.18 to 0.5 kg/hr. Residence times varied from 0.5 to 1 sec. The results
and operating variables are summarized in Table 3.
The most recent microwave plasma detoxification studies are dealing
with the scale up of this process (Hertzler, et al., 1979). An expanded
volume, 5-kW system was constructed with a throughput of 2 to 11 kg/hr.
3.1.6 Ozonation Processes
Ultraviolet (UV)-ozonolysis is a process that destroys or detoxifies
hazardous chemicals in aqueous solution utilizing a combination of ozone
and UV irradiation. Fairly simple equipment is required on the laboratory
scale: a reaction vessel, an ozone generator, a gas diffuser or sparger, a
mixer, and a high mercury vapor lamp (Wilkinson, et al., 1978).
TABLE 3. SUMMARY OF MICROWAVE OXYGEN PLASMA REACTIONS
Microwave Feed Pressure Oxygen
PCB Power, Rate Gas Flow
kW kg/hr Pa (torr) 1/hr
Aroclor 1242 4.6
Aroclor 1242 4.2
Aroclor 1254 4.5
0.27 2300-4700
(17-35)
0.5 2500-4800
(19-36)
0.18 1700-3300
(13-25)
323
395
360
Reactor Conversion
Packing
(%}
Wool plug
Wool plug
Solid
quartz rings
99
99
99
Sources: Bailin and Hertzler (1976) and Bailin (1977)
40
-------
The hazardous material in aqueous solution is placed in a plastic or
steel reactor fitted with a gas diffuser or sparger at the bottom. A tem-
perature sensing device, an electrode for monitoring pH, and a mixer or
impeller are contained with the reactor. A high pressure mercury lamp is
placed inside the solution to provide a source for UV radiation. Ozone is
generated by electrical discharge. Excess ozone is vented out through a
potassium iodide trap.
Process development and demonstration of UV-ozonation of dilute aqueous
streams contaminated with various PCB levels was carried out by Westgate
Research Corporation under contract to General Electric Corporation (Arisman,
1979). This technology is still in the research stage, but it has been
shown to be effective on the bench scale in destroying PCBs and degrading the
products to C02> KC1, and HpO (Versar Inc., 1976). The bench scale experi-
ments used a 36" x 6" cylindrical reactor. Ozone and oxygen were diffused
from the bottom of the reactor through porous ceramic spheres. Ozone concen-
trations were 2-3 percent in 02- The total 0« mass flow rate varied from 35
to 120 ng/min. A volume of 11 liters of PCB-contaminated water was treated
oer batch. Reaction times varied from 1-2 hours. PCB concentrations ranged
from 20-50 ppb. Important variables effecting the reaction are: 03 mass
flow rate, 0, concentration, UV intensity, and residence time. The results
of these bench tests gave approximate information about UV-ozone reactor
sizing, ozone generator output requirenents, and the effect of UV light on
the rate of oxidation (Arisman, 1979). This UV-ozonation process applies
only to dilute aqueous streams and not to non-aqueous fluids containing high
concentrations of PCBs. Figure 10 depicts basic apparatus needed for ozona-
tion.
3.1.7 Photolytic Processes
Ultraviolet radiation may drive chemical reactions in many chlorinated
hydrocarbons under controlled laboratory conditions (Mitchell, 1961). Much
research has been done on the photodecomposition of various classes of pesti-
cides by using UV light (Crosby and lee, 1969; Plimmer, 1970, 1972, 1977; and
Rosen, 1971). The photodecomposition of PCB is now being studied in the
laboratory to determine the structure of the resulting products and the
41
-------
MIXER
UV LIGHT
SPARGED
BATCH
REACTOR
x-
C
_^
EXHAUST GAS
^
3
*
IMPELLER
i i | i i i
-T~
A
d
I
£>
>
/CX
V
OZONE
GENERATOR
t
$
y
TEMPERATURE
CONTROL
pH MONITORING
""""""" AND SAMPLING
b T*KI VENT
SOLUTION "
POWER
I
?>
OXYGEN OR AIR
Figure 10. Schematic for ozonation/UV irradiation apparatus
(Mauk, et al., 1976).
42
-------
effects of solvents on product formation and rates of reaction (Ruzo, et al.,
1974). At the present time, not much is actually known about the photochem-
ical properties of the various 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 (Hutzinger, et al.,
1971; Ruzo, et al., 1974). In 1974, a study was carried out to determine the
reaction products of PCB photodecomposition in different solvents. The lab-
oratory apparatus used to study the photodecomposition was fairly simple.
Low and medium pressure mercury vapor lamps were normally used. Photolysis
was carried out at temperatures from 298 to 313°K. Fifty ml of 0.005 M tetra-
chlorobiphenyl in either hexane or methanol solutions were exposed to UV
light for 10-15 hours. HC1 was observed to evolve from the solution. The
products contained in the methanol solution consisted of dechlorinated PCB
and certain methanol substitution products. The amount of methoxylated pro-
ducts did not exceed 5 percent of the total amount of products formed. It
was determined that the rate of dechlorination was dependent on the extent
to which the particular chlorines increased or decreased the probability of
an excited state configuration of the molecule. It was concluded that the
photolysis of PCBs at wavelengths greater than 290 nm indicated a possible
use of this process on the industrial scale.
If photolysis is to occur, the molecule must absorb light energy above
290 nm or receive energy from another molecule through an energy transfer
process. The initial step of the photolytic reaction usually involves fission
of the parent molecule to form free radicals. These intermediates are un-
stable and react further with the solvent. Other organic molecules, inor-
ganic species, radicals, etc., may be formed. The product may be a complex
mixture in which isomerization, substitution, oxidation, or reduction pro-
cesses have occurred. To date, there have not been any studies incorporating
photolysis on PCB contaminated mineral oils or hydraulic fluids.
3.1.8 Reaction of_PCBs_ With Sgdium-Oxygen-PolyethyJene Glycols
This process is based on the discovery that molten sodium metal in a
certain solvent medium can serve as a chemical reactant. The reactivity is
43
-------
dictated by the mechanism of decomposition of the PCB molecule. Through
extensive laboratory experimentation, it was determined that the reacting
solution should be composed of 200 ml of polyethylene glycol (avg. M.W. =
400), dried over anhydrous Na^SO., and 2.3 grams of metallic sodium. The
temperature was raised above the melting point of the metallic sodium
(370.28°K) and stirred vigorously. After the remaining droplets of molten
sodium disappeared, 1 ml of PCB oil was added to the solution. The tempera-
ture of the system rose to 453°K. After 30 seconds, a gas chromatographic
analysis showed approximately 95 percent decomposition of the PCB oil. The
reaction evolved a large amount of HL gas. The small amount of sodium re-
maining in the solution was washed with methanol and water. Water soluble
Cl" was present. Infrared and NMR analysis showed that the PCB oil was con-
verted to polyhydroxylated biphenyls and hydroxybenzenes. These compounds
were also found to exist inthe water layer. Formation of NaCl by precipita-
tion also occurred and was analyzed for by x-ray diffraction. Analysis of
the reaction mixture by mass spectrometry showed the absence of chlorinated
organic material. It was concluded by the researchers that the two ingre-
dients essential for dechlorination of PCBs in polyethylene glycols were
sodium and oxygen (Pytlewski et al., 1980). The reference gives a detailed
analysis of the postulated mechanism for this reaction.
To date, this process has not been scaled up from the laboratory; how-
ever, the possibility of recovering hydrogen gas, polyhydroxylated biphenyls,
and NaCl on a large scale exists.
3.1.9 The Sunohio Process
Sunohio (1980) has developed a process to break down the PCB molecule
into its two primary components, biphenyl and chlorine. Organically-bound
chlorine is converted to chloride. The biphenyl molecule is converted to
polymeric solids. As the chemical reactions occur, the biphenyl nuclei
polymerize to form chains and branched chains of biphenyl molecules. The
process is called PCBX which is a Sunohio trademark. A full scale station-
ary model is now completed. A fully operational mobile unit is either com-
pleted or near completion at this time. This unit is designed to perform
the following duties: 1) it treats the transformer oil by filtering it,
removing moisture, acids, and other contaminants; 2) it removes and destroys
44
-------
all PCBs contained in the transformer oil but not the oil itself; and 3)
it destroys pure PCBs. The equipment needed to process the PCB oil is con-
tained in a large tractor/trailer. It is self-contained and can either
generate its own power or can be hooked up to an external electrical power
source.
The initial mobile processing unit is designed to handle about 1.9 m /hr
(500 gal/hr) of transformer oils containing up to 1000 ppm of PCBs. A gen-
eralized process description is as follows. A gas chromatograph analysis
is run to determine PCB content. The contaminated oil is passed through the
conventional treatment facility to remove moisture and contaminants. A
vacuum degasser elevates the temperature of the oil. Oil is passed through
the entire apparatus and reagent is added at a rate that is consistent with
the flow rate of the oil and the PCB content. The oil is heated to reaction
temperature and goes to the mixing chamber where the reagent is thoroughly
metered and mixed. The oil next enters the reaction vessel. After leaving
the reaction vessel, it goes through a heat exchanger and exchanges heat with
the oil that will enter the vacuum degasser, This cools the PCB oil to the
correct temperature. It next goes through two stages of filtration. Next,
it becomes the counterflow in the first heat exchanger, since it needs to
acquire heat again before vacuum degassing. After the vacuum degassing step,
it is returned to the transformer or held in the retention tank.
The degradation of pure PCB is similar to the above process. A quanti-
ty of oil is retained in the retention tank and continuously recycled. Pure
Aroclors can be destroyed at an approximate rate of 19 liters per hour.
Overall, the nrocess depends on the use of a commercially available re-
agent which abstracts chlorine atoms from the biphenyl nucleus. The specific
chemical reactions are carried out under controlled conditions of process
time, temperature, and reagent amount. Selective filtrations remove any
excess reagent and all the products. Transformer oils can be removed from
fully charged transformers and, after treatment, can be returned to the same
transformer in minutes.
The goal in developing this process was to remove all the PCBs from the
fluids treated. Fluids used in laboratory studies contained from 100 ppm to
45
-------
10,000 ppm PCBs. The treated fluids contained 0 ppm to 40 ppm PCBs respec-
tively after one treatment.
Optimum reaction conditions have been established for the following
primary variables:
1. Reaction temperature: the temperature is well below the
flash point of tyoical hydrocarbon fluids.
2. Reaction times: a few minutes retention time is adequate
to meet process requirements.
3. Reagents: reagent amounts about four times the theoretical
amount are optimum.
This process has also been applied to silicone oils. The PCBs were destroyed
by the process, and the silicone fluid appeared to be unchanged. More testing
is required to orove the reliability of the PCBX process for application to
all silicone fluids. Specific process data are not available from Sunohio
at this time.
3.1.10 Catalyzed Wet Air Oxidation
This process is based on the fact that a solution of any organic material
can be oxidized by air or oxygen if enough heat and pressure are applied.
Therefore, at temperatures of 423 to 613°K and 3.1 MPa to 17.2 MPa, sewage
sludges will be oxidized to alcohols, aldehydes, and acids. At higher tem-
peratures and pressures, the organic material can be oxidized to C02 and H-O
(Astro, 1977).
Recently, IT Enviroscience, Inc., (ITE) has developed a catalyzed wet
air oxidation process for the destruction of PCBs. Their process is patented
and involves the direct oxidation of PCBs by air or oxygen in an acidic
aqueous medium at high temoeratures. 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 are minimized in driving the dissolution of oxygen from air and
46
-------
the subsequent reaction with various organics in solution. The catalyst
itself is used to promote the necessary oxygen transfer. The ITE catalyst
systems speed up the transfer of oxygen to the dissolved state by using the
gas and liquid phase reactions based on the reactions of the catalyst com-
ponents with the organic material in the reactor.
The decomposition process scheme consists of a controlled stirred tank
reactor containing the catalyst solution. Air and the PCB wastes are pumped
into the reactor continuously. The organic materials are oxidized with the
heat of reaction used to drive off water, CO-, N~> water vapor, any volatile
organic material, and any inorganic salts formed. Condensible organic
material and water are returned to the reactor. Any inorganic salts or acids
formed are removed by treatment with the catalyst solution in a separate
stream. Vent gases are minimal and can be treated by absorption, adsorption,
or scrubbing. ITE emphasizes that the most important features of this pro-
cess are than non-volatile organic materials remain in the reactor until
destroyed and there is no aqueous bottoms product.
When the feed enters continuously, PCBs are added to the reactor at
their steady state destruction rate. The PCBs are consumed at the same rate
they are added to the system. If the catalyst solution needs disposal, the
reactor will need to be batch operated to destroy the remaining organic
material. Complete destruction of the organic material occurs at this
point, and concentrations are reduced to ppm or ppb levels. A pilot plant
is now under construction by ITE to demonstrate the process.
An alternative to the continuous process is a direct scale up of the
laboratory batch reactor. In the batch process, PCBs, oxygen, and catalyst
solution are fed to the reactor. The reactor is then sealed and heated.
The reaction proceeds for two hours at 523°K and 6.9 MPa. Next, the reactor
is cooled and vented. It is important to note that vent gas is not produced
while the PCBs are being destroyed. The cycle is then repeated again. After
six batches, the HC1 produced by the oxidation is distilled from the reactor.
In order to destroy residual PCBs in the catalyst solution, the reactor
should be run for 12-24 hours, approximately once a week.
Both of these catalytic wet oxidation processes, continuous and batch,
have been shown in laboratory scale tests to be able to destroy at least
47
-------
99 percent of the PCBs. There are several programs under way to commer-
cialize and scale up these processes. Figure 11 depicts the process sche-
matic for PCB destruction by catalyzed wet air oxidation.
3.2 BIOLOGICAL METHODS
The hydrophobic characteristics of PCBs promote their adsorption from
aqueous solution onto available surfaces. The type of surface determines
the amount of PCBs being adsorbed (Hague, et al., 1974). Hague and Schmedding
(1976) studied the adsorption characteristics of three PCB isomers by a few
different adsorbents and concluded that adsorption increases as the number
of chlorine atoms on the molecule increases. Current information indicates
that PCBs have a strong adsorption attraction towards soil and that the or-
ganic matter content of the soil and the chlorine content of the PCB molecule
are the primary factors affecting adsorption. Laboratory tests have shown
that PCB degradation by microorganisms in the soil could be an effective
process for PCB elimination (Briggs, 1973; and Scharoenseel, 1978).
The above studies indicate that PCBs are biodegradable to a certain
degree and can be attacked by soil microorganisms. Studies indicate that
an enriched culture of soil microorganisms could degrade PCBs at an appre-
ciable rate. Biological methods would generally apply to dilute aqueous
systems only. A precise value for the solubility of PCBs in water is ex-
tremely difficult, if not impossible, to determine since PCBs found in trans-
former and capacitor dielectric mineral oils. For example, the solubilities
of Aroclors 1016, 1221, 1242, 1254, and capacitor fluid at room temperature
were found to be 906 ppb, 3516 ppb, 703 ppb, 70 ppb, and 698 ppb, resoectively
(Griffin, et al., 1980). Additional studies need to be carried out to deter-
mine the effects of microoorganisms on the PCB degradation process. In most
studies, only the more water-soluble PCB isomers were used. Since water
soluble and total PCBs have different proportions of PCB isomers (Hague, et
al., 1974), no conclusive evidence regarding microbial degradation of PCB
contaminated capacitor or transformer fluids can be presented.
3.2.1 Activated Sludge Methods
Activated sludge processes are used for treatment of wastewater. Com-
plete aerobic treatment without sedimentation is carried out as the wastewater
48
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PROCESS SCHEMATIC FOR PCB DESTRUCTION
BY CATALYZED WET OXIDATION
CONDENSER
OXYGEN
LIQUID PCB
300 Ibs/BATCH
10
MAKE-UP
CATALYST
SOLUTION
o
WATER
VENT
POLISHING
TREATMENT
(IF NEEDED)
I !
I
I
I
LESS THAN .03
Ib PCB/BATCH
( > 99.99%
CONTAINMENT)
WATER
SCRUBBER
LABORATORY SIMULATION THROUGH
ONE PROCESSING SEQUENCE:
> 99% DESTRUCTION OF PCB'S
1% STILL IN REACTOR FOR DESTRUCTION
IN NEXT SEQUENCE
NO DIOXIN (TCDD)
I
POLISHING
TREATMENT
(IF NEEDED)
Figure 11. Process schematic for PCB destruction by catalyzed wet
air oxidation (IT Enviroscience, 1980).
-------
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 clarifier and are returned to the aera-
tion tank. The effluent emerges from the final settling tank purified.
Activated sludge treatment is classified as an aerobic treatment process
because the microbial solution is suspended in a liquid medium containing
dissolved oxygen. It is important that aerobic conditions be maintained
in the aeration tank. Dissolved oxygen extracted from the liquor is re-
plenished by air to the aeration tank. The various engineering unit processes
are: sedimentation basin, aeration basin, clarifier, sludge dewatering, and
chemical storage.
Tucker, Litschgi, and Mees (1975) did some work 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. With Aroclor 1221, only the 3-, 4-, and 5-chlorine isomers
were not degraded. Mihashi, et al. (1975) reported 50 percent PCB degrada-
tion in activated sludges. He also reported that the degree of PCB degra-
dation decreased as chlorine substitution onto the rings increased. It was
also found that the degradation of water-soluble Aroclor 1242 by mixed
cultures of soil microorganisms occurred in a short period of time. The
lower chlorinated isomers were more readily degraded than the higher chlo-
rinated isomers. The rates of degradation ranged from the monochloro iso-
mers which were degraded 100 percent within 6 hours to the tetrachloro iso-
mers which were degraded 42 percent after fifteen days. The major micro-
organisms found in the activated sludge were alkaligenes odorans, alkigenes
denitrificans, and an unidentified type of bacterium. Figure 12 is a flow
diagram of the activated sludge process.
3.2.2 Trickling Filter Methods
Trickling filters are another biological treatment option for the de-
gradation of dilute aqueous organic waste streams only. The filter con-
sists of crushed rock, slag, or stone. These materials provide a surface
50
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NUTRIENT FLED
w
Cg!^*^ PRIMARY
CLARIFIERS
EQUALIZATION
BASINS
EXCESS SLUDGE
MECHANICAL
AERATORS
AERATOR DASINS
RECYCLE SLUDGE
i pr LI I I IJIJJ I
SECONDARY
CLARIMERS
EXCESS
SLUDGE
DEWATERING
Figure 12. Flow diagram of activated sludge process (llansen, et al . , 1978).
-------
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 unsoluble 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. The major components of a trickling filter are a rotary distri-
butor, an underdraw system, and filter media. Influent waste water is pumped
into the rotary distributor for uniform spreading over the filter surface.
The rotary arms are driven by the reaction of the waste water flowing out
of the distributor nozzles. The effluent is carried away by the underdraw,
and air is circulated through the bed. The quantity of biological slime
produced is controlled by the amount of organic waste available to digest.
The maximum growth is controlled by various physical factors including
hydraulic dosage rate, type of media, type of organic matter, amounts of
nutrients present, and the nature of the particular biological growth.
Trickling filters are classified as either low (standard), intermediate,
high, or super rate filters, based on hydraulic and organic loading rates.
Since an aqueous medium is necessary, only dilute soluble PCB isomers
may readily be contacted with the active microbes. In the general case,
PCBs comprising mineral oil dielectric fluid and capacitor fluids will not
be degraded by the active microbes, since their solubility in water is
extremely low. Figure 13 is a flow diagram of high rate trickling filter
process.
3.2.3 Special Bacterial Methods
A few newer biological disposal systems are currently being developed
to improve the performance of trickle filters and activated sludge reactors.
These newer processes are mainly untried as disposal techniques.
Biodisc treatment is a type of thin film biodegradation in which large
plastic discs are partially submerged in the aqueous waste solution. The
aerobic microorganisms colonize the disc surfaces and are oxygenated as the
discs are rotated. A well aerated surface is created by arranging a line of
discs in series. This creates a well aerated surface requiring little soace
for biological activity (Autotrol, 1971).
52
-------
en
OJ
.$&
^ PRIMARY
CLARIFIERS
EXCESS SLUDGE
SECONDARY
CLARIHERS
LIQUID
RECYCLE
EXCESS
SLUDGE
LIQUID
EI-Tl UEKil
Figure 13. High rate trickling filter flow diagram (Hanson, et al., 1978).
-------
The Bio-surf process has been added to facilities to upgrade the ef-
fluent treatment system. Anerobic conditions can be created by enclosing a
submerged Bio-surf system and adding a carbon source such as methanol (Auto-
trol, 1974).
Ecolotrol, Inc., has developed a full scale biological fluidized bed
process, utilizing sand as the particle growth medium. A large population
of microorganisms makes possible a faster treatment than conventional bio-
logical treatments such as activated sludge or trickle filters. A clarifier
is not required with the Ecolotrol system. These units have been used on
municipal wastes and on a pilot plant scale for processing pharmaceutical
and petroleum tank truck wastes (Wilkinson, et al., 1978).
VJornes Biochemicals has developed a freeze dried biochemical solution
containing mutant bacteria and various substances to facilitate their growth.
Various chlorinated benzene derivatives including hexachlorobenzene have
been degraded (Phenobac ' 1977).
None of these processes have been directly applied to non-aqueous
systems. Because of the insolubility and stability of the PCB molecule,
adaptability of these processes to the immediate problem of PCB degradation
in non-aqueous materials will be difficult.
54
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4. EVALUATION OF PHYSICOCHEMICAL PROCESSES
4.1 ADSORPTION PROCESSES
As stated in Chapter 3, activated carbon adsorption processes are applied
primarily to aqueous streams. An extensive literature search was carried out
to find information on activated carbon adsorption processes applied to PCB
removal from heat transfer fluids. This search did not uncover any pertinent
information. The U.S. Air Force (U.S. Air Force 1976) funded studies on us-
ing activated carbon to remove TCDD from Herbicide Orange provided most of
the background information for non-aqueous carbon adsorption processing methods,
The following treatment is based on procedures used in the Herbicide Orange
study. Direct applications of this process to the disposal of PCBs may be pos-
sible. It is worthwhile to evaluate and assess the merits and downfalls of
the U.S. Air Force study.
4.1.1 Technical Factors
From a technical point of view, adsorption processes for removing hazard-
ous compounds from liquid streams are attractive because of the possibility
of resource recovery. In other words, it may be possible to remove the PCBs
from a mineral oil dielectric fluid and reuse the purified mineral oil.
4.1.1.1 State of Technology--
Activated carbon adsorption technology is well developed for aqueous
stream purification and is used widely for municipal water purification. Ad-
soprtion techniques are not well defined for non-aqueous systems at this time.
As stated in Chapter 3, activated carbon was used to remove TCDD with an aver-
age concentration of 2 ppm from Herbicide Orange. TCDD was reduced to 0.1 ppm
or less, and the process was considered successful. The U.S. Air Force con-
cluded that the technology to dispose to the TCDD contaminated activated
charcoal did not exist, so the Herbicide Orange stocks were incinerated at
sea (Ackerman, et al., 1978).
55
-------
4.1.1.2 System Design
The reprocessing plant would consist of the following units:
Mineral oil storage tanks
Heating tank
Boiler to provide steam to the heating tank
Activated charcoal cartridges
Product tanks
Appropriate pump, filters, piping, etc.
Overall processing should be evaluated as to the performance or operat-
ing characteristics of each individual unit.
4.1.1.2.1 Pretreatment and feedThe feed will be a mineral oil contaminated
with PCBs, possible acids,and other trace substances, such as metals and in-
erts. These should be removed before contact with major processing equip-
ment. Conventional pretreatment technologies could be used for this purpose.
An activated carbon adsorption facility typically has minimal pretreatment
equipment since most noxious materials will be adsorbed onto the activated
carbon.
4.1.1.2.2 ProcessingUnit processes of principal interest to PCB disposal
and those requiring evaluation are the heating tank, the adsorption columns,
the filtering process, and the process tanks.
The PCB material in the heating tank will have to be evaluated care-
fully. The PCB oil will be heated ana sent to the carbon adsorption col-
umns, so the optimum processing temperature should be determined carefully.
Column performance should be evaluated for optimum charcoal pellet
size, texture, and composition. Pressure drops and flow rates must be
assessed to insure smooth operating. Test runs with alternate types of
activated charcoal should be carried out to determine optimum column effi-
ciencies. Adsorption cartridge configuration is an important operating
variable and must be evaluated critically. The adsorption cartridges
should be operated in a series configuration for best results. Pilot
plant studies will be needed to study the proper amount of carbon needed
for PCB removal. A process control scheme must be developed for the
56
-------
cartridge configuration to control the flow direction so any cartridge can
be made first, second, etc., in the series. Expended cartridges must be
removed, so the cartridge replacement method must be developed to efficient-
ly replace the old cartridge with a minimum risk of accidents. This will
insure that the PCB material is further treated by new carbon, thus increas-
ing the PCB reduction. When the used cartridge is removed from the system,
it should be sealed at both ends to insure against PCB or other hazardous
material leaks.
Pilot plant studies are needed to define the necessary process para-
meters such as flow rates, temperature, pressures, as well as types of
pumps, filters, heat exchangers, etc. The process parameters will depend
on the type of PCB waste to be detoxified.
4.1.1.2.3 Pollution control--The use of activated carbon filters on all
vents, leak-free pumps, and plumbing, coupled with the use of sealed car-
tridges, should prevent any escape of PCB material to the environment.
Every effort should be made to minimize the release of vapors from the
various units and from the dedrumming facility. All equipment that con-
tacts the PCB material should be sized properly to avoid potential leaks
or spills. The plant engineering should be such that potential problems
will be minimized, and contingency plans should be developed to reduce
the consequences of accidents from faulty pollution control equipment. All
cartridges should be made of new steel to prevent ruptures. The weight of
the column should determine what type of equipment should be utilized in
removal/replacement of the cartridges. Charging the cartridge with carbon
and the PCB oil must be done very carefully. It will be necessary that the
cartridge is charged before being put on stream. The plant, from the pro-
cess tanks to the filling of drums with products, should be designed for
closed loop containment of vapors. If vapor exhaust is required, it should
be run through carbon filters.
There will be no liquid effluent produced in this process. Mo water
or solvent is used in the reprocessing plant. The used adsorption car-
tridges and air-scrubbing carbon filters must be sealed and prepared for
placement in a recoverable storage structure. Upon completion of the pro-
cess, the plant facilities should be cleaned with solvent.
57
-------
4.1.1.2.4 Destruction efficiencySince activated carbon adsorption
processes have not been applied to removal of PCBs from heat transfer
fluids, destruction efficiencies cannot be estimated. PCBs would not
actually be destroyed but will be adsorbed onto the charcoal for further
processing. Destruction efficiencies do not really exist as such for this
process. Based on the U.S. Air Force funded study on TCDD removal from
Herbicide Orange, it may be expected that PCB removal could be as high as
95%. It is doubtful whether any activated carbon absorption process will
be capable of destruction efficiencies equivalent to those of Annex I in-
cinerators or high efficiency boilers.
4.1.1.3 Process Controls
There are five major operations in an activated carbon adsorption
process that will need to be controlled:
o Dedrumming the PCB material and pumping it into plant storage
tanks
Heating and processing the PCB material including cartridge
changing
Redrumming the finished product
Removal of the contaminated carbon cartridges and air filters
from the reprocessing system, and preparation of them for
recoverable storage
Disposal of empty mineral oil drums and other contaminated
material
Each one of these major operations must be evaluated in terms of
what type of process control schemes are used to regulate the particular
operation. Process control should focus on creating a failsafe disposal
method for the PCBs.
Temperature control is necessary in all heating tanks. Optimum
adsorption will occur at a specific temperature. Heat exchangers or heat-
ing elements must be controlled to maintain proper operating conditions.
Flow rates will also need to be controlled to insure smooth and steady
operations. Adequate flow controllers should be installed downstream of all
critical pumps.
Each activated carbon adsorption facility will need to be evaluated
separately for overall control of important process variables. The
58
-------
process control scheme should adequately eliminate guesswork and risk in
operating the overall disposal process.
4.1.1.4 Effluent Monitoring--
Air quality monitoring could be done in several different ways: 1)
use of ambient air samplers placed at specific locations around the repro-
cessing plants, 2) use of biomonitoring plants located at various areas
around the facilities, and 3) visual observations of native flora in the
general vicinities of the reprocessing plants. All the air sampling in-
struments used should have a high demonstrated efficiency under field con-
ditions. Periodic air samples should be collected and analyzed for PCB
content and total composition. In addition, post-operational samples
should be collected and analyzed.
As mentioned earlier, there will be no aqueous waste streams nor
release of any raw or processed PCB material to surface or groundwaters.
Processed PCB oil will be transferred directly to drums and transported
by rail or truck.
4.1.1.5 VJaste Characterization--
Activated carbon adsorption processes are best suited to handle aqueous
streams, contaminated with PCBs. Municipal water treatment plants currently
utilize this technology for waste treatment. If the process is to be
adapted to non-aqueous waste treatment, certain modifications of the basic
design will need to be incorporated into the overall process scheme.
4.1.1.5.1 Range of PCB concentrationsNo information on tolerable levels
of PCBs was found. Aqueous purification systems will contain very dilute
amounts of PCBs, perhaps at ppb levels. Based on the U.S. Air Force
funded study on Herbicide Orange, a similar activated carbon adsorption
purification system should be able to be developed to handle PCB transformer
fluids with a PCB concentration of greater than 500 ppm.
4.1.1.5.2 Limitations on constituents--PCB wastes containing excessive
concentrations of toxic heavy metals will require pretreatment prior to
entering the adsorption column. The extent and type of treatment will
depend on the nature of the metals. Any contaminants that could cause
fouling or corrosion of process equipment may also need to be eliminated
59
-------
or reduced by pretreatment. Any substituent that could interfere with
the charcoal adsorption process will also need to be eliminated by pre-
treatment.
4.1.2 Environmental Factors
Because no references on disposal of non-aqueous PCBs by activated
carbon adsorption treatment were found, it is difficult to estimate the
environmental impacts of this process.
4.1.2.1 Potential Impacts of Disposal Operation--
During reclamation, the use of activated carbon filters on all the
vents, plumbing, and sealed cartridges should prevent any significant
escape of the PCB material to the air. Operations that could result in
the release of toxic material to the air are:
Dedrumming the PCB material and pumping it into storage
tanks
a Heating and processing the PCB material including cartridge
charging
Redrumming the finished product
9 Removal of the contaminated carbon cartridges and air filters
from the reprocessing system, and preparation of them for
recoverable stroage
Disposal of empty drums and other contaminated equipment
Operations 1 and 3 would involve transfer of the PCB material at or
near ambient temperatures. Because of the low volatility of PCBs in this
temperature range, the potential impact should be minimal. Operation 2
requires heating the herbicide and maintaining it at this temperature
during the low-pressure adsorption process. The environmental impact from
this step could be signficant since the volatility of the PCB material will
be increased by heating. Process accidents at this stage could result in
the release of high quantities of PCB to the atmosphere.
Operation 4, removal and preparation of the contaminated carbon car-
tridges and air filters for storage has minimal potential for introducing
PCBs into the atmosphere. The cartridges will be closed to the environ-
ment before removal from the system. Operation 5 involves dismantling and
disposal of the parts of the dedrumming and reprocessing equipment that
60
-------
come in contact with the PCB material. This material will have only low
levels of contamination since it will be reused or flushed with a suitable
solvent following completion of reprocessing. Overall, there will probably
be small quantities of PCBs released into the atmosphere during reprocess-
ing. An evaluation of the process should include extensive air sampling
using sensitive analytical methods.
Since during reprocessing there will be no aqueous waste streams, nor
release of any raw or processed PCB oil to surface or groundwaters, there
should not be any impact on water quality. The only possible impact on
water quality would be in the event of a spill directly into drainage
ditches from storage to the reprocessing plant. This risk could be mini-
mized if strict precautions are taken to prevent accidental spills. Stor-
age of carbon cartridges and filters pose no anticipated impacts on water
quality.
4.1.2.2 Potential Impacts of Disposal of Process Wastes-
Overall, environmental impacts of the disposal of process wastes
should be very low with the use of additional engineering constraints such
as carbon-filtered vents and leak free pumps. These should be incorporated
to eliminate discharge of the PCBs to the ambient air. There should be
minimum impact from discharges to the air from drum disposal if the drums
are crushed after drainage of the solvent. The crushing will reduce the
possibility of residual PCBs entering the environment while the crushed
drums await shipment to a steel manufacturing plant. The environmental
impact associated with the storage and transport of these drums should not
be significant. Evaluation should focus on each unit process separately
and on the associated risks of each one. Extensive monitoring and sampling
will have to be done to determine possible toxic material escape points.
As stated earlier, there should not be any anticipated impacts on water
quality from the reprocessing units.
4.1.2.3 Potential Impacts of Accidents-
Accidental spills or leaks of PCBs from an activated carbon adsorption
facility may pose the following threats:
o Contamination of surface or groundwater
-------
t Contamination of land areas where humans, animals, or
croplands could be exposed
Contamination of areas that could lead to significant
airborne movement of PCBs
Contamination of surface or groundwater if the PCB oil is
discharged directly into the environment.
Facilities disposing of PCBs must have spill prevention contingency
plans. These plans should include spill control strategies and counter-
measures. These plans should detail safe handling procedures of the PCB
material. The goals of these plans are to prevent discharges and to mini-
mize impacts of spills. An adequate SPCC plan should minimize the poten-
tial for spills and hence, potential environmental impacts from spills.
The typical activated carbon adsorption treatment plant is not in the
hazardous waste disposal business. It is not expected that such a plant
will be constructed in accordance with RCRA standards for hazardous waste
disposal facilities. Because of the threat to the environment of potential
PCB spills, an activated charcoal adsorption treatment facility should be
evaluated carefully with respect to PCB storage and containment. It is
recommended that adequate storage, as mandated by PCB regulations 40 CFR
761.42, be provided before the facility is approved.
4.1.3 Economic Factors
Capital and first year operation costs for a typical activated carbon
adsorption facility are depicted in Tables 4 and 5. Since this pro-
cess has not been directly applied to PCB disposal in non-aqueous streams,
a cost analysis cannot be done at this time. It may be possible to use the
following data as a guide for determining whether or not an activated car-
bon adsorption process is worthwhile.
The most costly unit process is the carbon adsorption columns together
with the regeneration system. The total capital cost for a 0.31 m facility
was $1,205,423 based on mid-1978 dollars. Energy and chemical requirements
comprise over 90% of the direct operating costs. The total first year oper-
ating costs including administrative overhead was $4,623,416 (based on mid-
1978 dollars).
Possible credits could exist for the processed PCB material, though
this will depend on the overall effectiveness of the adsorption process.
-------
cr*
CO
TABLE 4. SUMMARY OF CAPITAL COSTS FOR CARBON ADSORPTION
(Hansen et al, 1978)
Cuplldl Cost
Cdtcijory Module
Carbon adsorption
Steam ijunuralor
tJjble punip
I'lpinij
luldl
Lupilal Costs
Sulilotal of
Cdpllal COatS
W,,,kl,,.j capital"
Alllff
(jidiid total of
capital costs
Costs
Site MiiLliunlcal
('reparation Structures Equipment
I 11.400 f 52.9000« $ GG2.0DO
1J 1.163 1?.
10.1100
1.125 --- 7?.!jll()
12.53d 54.063 C4II.2UO
141 .30J
...
...
...
...
Qiidiilltlcs
Electrical Land Oihur
Equipment Land Total (ft?) S Irani
ll.b/lii-
\ 5!i2 ( 3.430 --- 4,f>20
124 --- If. 7 C64
b52 3.!i54 4.71)7 664
$ B60.210
302.202
43.011
1,201.4^3
* Scale = S.OOO (jpm
I Hid-iy/H dollars
I Uul IdliKj
'* At one month of direct operating costs
| AlluiMiicu lor funds during construction al 5X of capital costs
11 liicliiilui inilidl carbon chuuje
-------
TABLE 5. SUMMARY OF FIRST YEAR OPERATING AND MAINTENANCE COSTS
FOR-CARBON ADSORPTION
(J-lansen et'al, 1978)
OJH Cost Type 1
Cate'jory Operator 1
Moduli; (17.77/lir)
Cailxin
adsorption 35.260
Steam
ijL-iiL-ialor !>'JO
WdilU p(IMI|l
I'lpimj
liil.il 3S.U'jU
Supplemental
O&M costs
iiiilituldl of
din-it O&M costs ---
Administrative
OVCllleadff
IV-lil ioivli.e and
illiilil Ll/ul lull"
Itudl L'ilolu taxes
mid liiini uiiccl ---
1 tit ol (irbl year
(J|Ji:l ulllHJ COilS
. . __ .
Ldbor
Type 2
Opurntur 2
(J9.l9/hr)
10.3%
lOb
UI.'jUl
Costs'
Type 3 CiiL-ryy Malntciidiicc CliL-mlcul Otlmr
laborer Electrical Costi Coilt. lutal KUII
(tb.ye/hr) (tO.(l3b/KWII) (yr)
10. OG/ 2.1(10.00(1 11U.OOO 1 .290 .1)00 --- J./44.000
7.7'JJ 'j.2HO --- 6.170
B.6JO
204 --- J63
4H.II!>4 2.IIJ.'JIIJ 119.363 1.2%. 170 --- 3.744.000
1.7/0
3.626.418
725,
-------
Generally, it appears that activated charcoal adsorption processes for
removal of PCBs from heat transfer fluids will require moderate capital in-
vestment and operating costs with a possible resource recovery credit.
4.1.4 Energy Factors
Activated carbon regeneration will take up the greatest proportion of
3
energy requirements. It is estimated that 0.46J/m of energy needed for
0.31 m /sec (5,000 gpm) process. Energy factors for the process adapted to
the non-aqueous disposal of PCBs cannot be developed at this time, but will
need to be developed if the process is to be applied.
4.2 CATALYTIC DEHYDROCHLORINATION
4.2.1 Technical Factors
4.2.1.1 State of Technology--
Catalytic dehydrochlorination of PCBs is a proven research method that
has not been scaled up. The results of a major study on Aroclor 1248 indi-
cate that chlorine can be catalytically removed from the PCB molecule and
replaced by hydrogen to produce non-toxic hydrocarbons (Lapierre et al.
1977). This study has created a foundation for commercialization of this
process.
4.2.1.2 System Design--
4.2.1.2.1 Pretreatment and feedFeed stream characterization of PCB mix-
tures is extremely difficult because of the oossibility of 210 isomers
existing in solution. Aroclor 1248 was used in the studies of Lapierre
et al., (1977). Materials to be treated should first be charged to a rotary
extractor. The PCB material to be dehydrochlorinated is extracted with hot
ethanol and pumped to the main reactor. This extraction is necessary to
separate the organic materials to be reacted from possible contaminants and
inert substances. Before the PCB material enters the reactor, the reactor
contents should be boiled at atmospheric pressure to evaporate the ethanol.
The ethanol should then be condensed and returned to the extractor until the
inert materials still in the extractor are free of PCB residues.
65
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4.2.1.2.2 ProcessingProcess design must consider choices between alter-
native process steps, equipment types, and various parameters such as sizes,
temperatures, pressures, residence times, flow rates, etc. A decision would
have to be made between implementation of a batch process or a continuous
process. A continuous process works best when a steady flow of feed of
uniform composition is available. This may not be the case in PCB process-
ing. A batch process may have to be utilized in at least the initial stages
of process development. The need for extremely high temperatures and pos-
sible problems with thermal degradation of the products indicate the pro-
cessing should be done in the liquid phase in a suitable solvent.
Solvent selection is crucial to this process. The solvent must be
adaptable to both the PCB molecule and to the acid acceptor which is need-
ed to reduce corrosion and to produce a clean effluent. The solvent must
be capable of being separated and recovered by distillation and should be
fairly inexpensive.
Operating temperature is a critical design parameter. Reaction at
high temperatures results in greater solubility of the PCBs, reduction in
the size of equipment, and a faster reaction. However, as more heat is
required, the total pressure required to raise the hydrogen partial pres-
sure will need to be increased.
The extraction step should be carried out at atmospheric pressure
to reduce equipment design complications. Dehydrochlorination should be
accomplished at high hydrogen pressures to insure adequate reaction rates.
Hydrogen partial pressures should be between 2-5 MPa.
Catalyst selection should be determined by the process requirements.
Catalyst life will vary according to the types of impurities found in the
feed and the severity of the reaction conditions. How well the catalyst
can be regenerated and its life span are important economic considerations.
Particle size and overall catalyst configurations need to be considered
when doing an activity study.
An acid acceptor is needed to reduce the corrosiveness of HC1. Also,
HC1 should be neutralized by the acid acceptor in order to reduce waste
emissions.
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4.2.1.2.3 Pollution control--Possible pollutants are HC1, hydrocarbons,
other simple chlorinated compounds, and salt. Appropriate pollution con-
trol devices would have to be installed to eliminate or reduce these wastes.
Absorption or scrubber units could be used to effectively control the eli-
mination of HC1. The hydrocarbons and other organic species should be separ-
ated from the waste stream by liquid-liquid extraction. As an alternative
to pollution control, the waste materials could be utilized for energy,
chemicals, or solvents elsewhere.
4.2.1.2.4 Destruction efficiency--The study carried out by Lapierre, et
al.(1977)}indicates complete conversion of PCBs into dechlorinated biphenyls.
High destruction efficiency may be assumed to be possible upon scale up of
this process.
4.2.1.3 Process Controls--
Important variables which need to be controlled are: temperatures,
pressures, flow rates, liquid level and composition. The measurement
equipment must give an accurate display of the desired variable. The type
and location of measurement and control equipment will need to be specified
upon scaleup. The temperature of all incoming streams must be monitored
and controlled, as temperature is perhaps the most important process vari-
able affecting the level of PCB conversion. Temperature and,therefore,
heat supplied to the reactor must remain within the optimum operating range.
An accurate control device should be installed for this purpose. Pressure
drops across the pollution control system and across the individual process
units should be measured and controlled. Abnormal pressure drops may dras-
tically affect the overall process. Flow rates of all important process
streams should be measured and recorded. Flow rates can be measured by use
of an orifice plate, sonic type of flowmeter, or rotometer. Flow rates
should be measured downstream of any pumps and in-line filters and upstream
of any flow control valves. Liquid levels in all storage tanks should be
monitored periodically to prevent overflow and to insure adequate flow of
these fluids to the process. Either gauge glasses or automatic sensors
could be used. Composition of the reactor solution should be controlled by
adjusting appropriate flow rates to the reactor. A more elaborate examina-
tion of required process controls cannot be done until scaleup studies are
underway.
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4.2.1.4 Effluent Monitoring
Careful effluent monitoring is needed to determine the extent of PCB
conversion and to determine the potential environmental impacts of any un-
destroyed PCBs.
Liquid effluent streams must be monitored for PCB content and for the
existence of HC1 and other simple chlorinated compounds. Conventional
monitoring devices such as chromatographs and spectrometers should be used
to examine periodic samples from all effluent streams. If a scrubber is
used, its effluent should be monitored and sampled on site and analyzed in
the laboratory. Liquid effluents should also be monitored for salt content
and dissolved solids.
No limit on the PCB content of scrubber water streams is given except
indirectly through reference to applicable effluent or pretreatment stand-
ards and any other State or Federal laws and regulations. There is no
limit, explicit or implicit given for the maximum PCB content of a solid
residue stream. The effluent monitoring capability of a facility is deter-
mined by the facility operator's description of the appropriate streams.
Prior to sampling any liquid stream, plant data concerning that stream
must be available. Tap sampling should be used to monitor flowing liquids
or liquids in tanks or drums. Automated samplers are available which can
sample almost any process stream. Use of these samplers increases the like-
lihood that a representative sample will be obtained.
Any vent gases should be monitored by using ambient air samplers.
Periodic air samples should be collected and analyzed for PCB content and
overall composition.
Any solid wastes should be sampled by a grab technique. The adequacy
of the solid sampling locations should include consideration of homogeneity
and amount of solid waste acquired.
4.2.1.5 Waste Characterization
4.2.1.5.1 Range of PCB concentrationsThe catalytic dehydrochlorination
process should be able to handle a wide range of PCB contaminated material
provided that they are in the liquid state. Transformers with a PCB concen-
tration >500 ppm as well as PCB capacitors and mineral oil dielectric
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fluids with PCS content 50-500 ppm should be treatable by this
process.
4.2.1.5.2 Limitations on constituentsThe feed must be in either liquid
or gaseous form. Inorganic and inert constituents should be removed prior
to processing. Any substances that could interfere with the dehydrochlori-
nation reaction or which could cause corrosion or fouling of process equip-
ment should be eliminated. PCB solubility in ethanol is an important pro-
cess variable, so any component in the feed stream that could alter this
solubility must be contained. Commercialization of this process will elu-
cidate other possible limitations on constituents.
4.2.2 Environmental Factors
4.2.2.1 Potential Impacts of Disposal Operation--
The potential impacts of the disposal operation appear to be minimal.
Product recovery of process wastes is a viable way of lessening potential
environmental impact. If the product turns out to be a fairly pure organic
liquid, refining may be used to produce convenient raw materials. In this
case, potential environmental impacts will be greatly reduced. If the pro-
duct is a complex mixture of hydrodechlorinated hydrocarbons, it may be
necessary to mix the solution with fuel oil and burn it in a furnace. If
chloride residues are significant, incineration may also be necessary.
This situation will greatly increase the potential for environmental damage.
If any solids exist in the waste streams, landfill dumping might be neces-
sary, and standard soil and toxicity studies would need to be carried out.
4.2.2.2 Potential Impacts of Disposal of Process Wastes--
According to current studies, a properly designed process should not
produce toxic off-gases or contaminated aqueous residues. A meaningful
assessment of toxicity has not been made yet. The effect of the partially
and totally dechlorinated products on the environment will have to be evalu-
ated in the overall assessment of the process. The commercial utility of
the waste products will also need to be determined in an environmental
assessment so decisions can be made between disposal or reprocessing.
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4.2.2.3 Potential Impacts of Accidents-
Accidental spills and leaks from PCB containing products such as trans-
formers during transportation and storage appear to be the greatest sources
of accidents. The possibility of environmental contamination of the atmo-
sphere from PCB losses from all processing units must be examined closely
in scaleup studies. All pressurized units must have appropriate safety
systems. Hydrogen gas is extremely flammable and volatile, and caution
must be exercised when working around this equipment. Common sense safety
practices should be able to prevent most accidents.
4.2.3 Economic Factors
There are no economic data available to permit an economic assessment
of the proposed dehydrochlorination conversion process. It is obvious
though that the hydrocarbons produced by this process would be much more
expensive as fuel oil than other commercial sources. An economic evalua-
tion must await development of engineering cost estimates. Qualitatively
it appears that capital investment and operating costs would be moderate,
and hydrocarbons could be recovered and sold to make the process more cost
effective.
4.2.4 Energy Factors
Since this process is primarily operated for PCB disposal, the amount
of energy required per unit weight of PCB destroyed must be calculated.
Lack of data prohibits this calculation at the present time. It must also
be determined whether or not energy credits may be gotten by recovering
some or all of the heat content of the PCB waste to use for steam produc-
tion.
4.3 CHLORINOLYSIS
4.3.1 Technical Factors
4.3.1.1 State of Technology--
Chlorinolysis has not been directly applied to PCB, however, the pro-
cess may be adaptable. The AG Hoechst chlorinolysis process described in
Chapter 3 can handle certain chlorinated benzene derivatives on a limited
scale . Chlorinolysis has been successfully commercialized.
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4.3.1.2 System Design--
Important system design factors are: pretreatment of the feed, the
reaction and reactors, distillation, HC1 absorption, and incineration of
waste residues.
4.3.1.2.1 Pretreatment and feedThe waste cannot be introduced directly
into the process equipment, but must be pretreated first. Light ends may
contain water which must be removed by a drying unit. Solids contaminated
with soot or other contaminants must be removed in a falling film evapora-
tor unit. The waste feed system includes all equipment used to process the
PCB wastes from the point of storage to the point of entrance to the reactor.
The drying unit should consist of at least two adsorbers and one regenera-
tion system. The feed can consist of a wide variety of chlorinated species,
however, the aromatic content should not exceed 5% calculated as benzene.
4.3.1.2.2 ProcessingThe process is almost completely enclosed. Generally,
a low quantity of chlorine is consumed,and low quantities of HC1 are pro-
duced. An example of the effectiveness of this process is illustrated by
the following stoichiometric equation:
1 kg residue + 2.73 kg C12 = 3.010 kg CC14 + 0.72 kg HC1
This reaction is more than 95% complete using a pressure of 20 MPa
and a temperature of about 873°K. Any heavy ends which are not completely
converted must be separated from the reaction products in the first distil-
lation column and recycled back to the reactor for final conversion. The
second distillation unit separates the reaction products, HC1. CC1., and
various other residues that have not been completely converted. The adsorp-
tion column produces a 31% HC1 solution and must be operated adiabatically.
It is important to note that all the chlorolysis reactions are exothermic.
The final temperature is controlled by an excess of chlorine and should not
exceed 893°K.
4.3.1.2.3 Pollution control--Waste gases containing C12 and HC1 must be
removed in an absorption unit. This same absorption unit also functions
as an emergency and normal shutdown system for the plant. Since incinera-
tion is used to eliminate the chlorine residues, attention must be paid to
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pertinent government regulations. During incineration, HC1 , C02, CO, and
H^O are formed. If the incineration unit functions improperly, trace
amounts of chlorine gas may also be formed. Important design parameters
such as residence time, temperature, and stack height must be calculated
accurately.
4.3.1.2.4 Destruction efficiency The destruction efficiency defined as:
DE = 100 PCBin - PCBQut can only be assumed to be very low for
chlorinolysis, since the destruction efficiencies of other polychlorinated
aromatic compounds are very low.
4.3.1.3 Process Controls-
Four important process control variables must be manipulated to
achieve adequate control of this system. They are: temperature, pressure,
flow rate, and liquid level. These variables must be measured, and suit-
able equipment must be used to regulate them.
The incinerator must be equipped with process controls to regulate
waste and air flows to insure proper combustion conditions such as tempera-
ture and oxygen level. The incinerator must also be equipped with automatic
shutdown systems in case of waste flow malfunctions. These controls can be
either manual or automatic.
Temperature controllers are needed to regulate the temperature of in-
coming streams to the pretreatment section, reactor, distillation columns,
and absorbers. Combustion temperature within the incinerator must also be
monitored and controlled. Pressure must be controlled in the reactor and
all of the columns. Pressure drops across the pollution control system
and across the various process units should be measured and controlled.
Flow rates must be measured and recorded for all waste streams. Flow rates
could be measured by an orifice plate, sonic-type flowmeter, or rotameter.
Flow rates should also be monitored and controlled downstream of any pumps
and upstream of any flow control valves. Liquid feed to the incineration
burner should be controlled to insure the correct mix of fuel and waste.
Liquid levels in all storage and processing tanks should be measured and
controlled to prevent overflow and to insure a free flow of fluid through-
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out the process. Either gauge glasses or automatic sensors could be used.
4.3.1.4 Effluent Monitoring
Waste gases containing C12 and HC1 must be removed in an absorption
unit. Effluent monitoring should be able to detect potential environmental
pollutants. Ambient air samplers should be used to monitor all waste gas
streams. Waste gas samples should be collected periodically for analysis.
If incineration is used to eliminate chlorine residues, then government
regulations specify that stack components must be monitored and sampled
at specific intervals. It is preferable that monitoring during incinera-
tion be conducted by collecting and analyzing samples from holding tanks
eliminating the need for frequent grab samples.
Liquid PCB wastes should be monitored by real-time measurement of the
bulk flow rate and automatic continuous recording. Standard devices are
commercially available for this purpose. The PCB concentration should be
determined by periodic sampling and analysis of the PCB waste feed.
Solid PCB wastes should be monitored by weighing loads and monitoring
the loading over regular intervals of 15 minutes or less. Waste residue
from the incinerator may be monitored by using a weight scale. The faci-
lity operator should keep a record of the total weight of residue.
The Regional Administration should have available a manual describing
sampling methods for the various streams that must be monitored.
4.3.1.5 Waste Characterization
4.3.1.5.1 Range of PCB concentrationThe chlorinolysis process has not
been adapted to handle PCBs as of yet.
4.3.1.5.2 Limitations on constituentsChlorinolysis works best on chlori-
nated aliphatic compounds. The feed must be a liquid with most solid impur-
ities removed before processing. The process works poorly for an aromatic
content of greater than 5% calculated as benzene. Feed material containing
phosphorous, nitrogen, sulfur, or toxic metals may not be appropriate for
chlorinolysis. The water content of the feed stream should be less than 20
ppm.
4.3.2 Environmental Factors
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4.3.2.1 Potential Impacts of Disposal Operation--
An environmental impact statement for a chlorinolysis plant has not
been formally developed but would be part of an overall assessment necessary
prior to construction. The primary environmental factors that must be con-
sidered are:
Shipment and handling of the hazardous organochlorine wastes
prior to chlorinolysis
Control of the potential gas and liquid effluents after
conversion
Handling and storage of the final products.
4.3.2.2 Potential Impacts of Disposal of Process Wastes--
Potential environmental dangers when considering the construction and
operation of a chlorinolysis plant include the sudden occurrence of carbon
tetrachloride in rivers and municipal water supplies and possible escape
of phosgene, HC1, C0,and carbonyl chloride gas into the atmosphere. There
are no data available describing emission of particulate matter from the
chlorinolysis process. Such material could be emitted from the incinerator,
but the lack of data prevents a discussion of expected impacts. The use of
a scrubber should keep these emissions fairly low. Since the waste effluent
streams are mainly liquid, any solid emissions would be dissolved in the
liquid effluent as suspended particles. The liquid effluents should be dis-
charged to a municipal sewage system after treatment. Residual organic or
trace element components would be contained in the sludges generated by the
municipal waste treatment system. If these sludges are landfilled, the
effects of contaminants deposited into the soil will depend on the type and
porosity of the soil.
4.3.2.3 Potential Impacts of Accidents--
Emissions from manufacturing, storage, and transport of polychlorinated
aromatics, and particularly PCBs are possible. Accidental spills and leaks
of both solid and liquid wastes are the primary sources of accidents. Al-
though leaching from sanitary landfills is theoretically possible, evidence
shows that losses by this route are negligible. Leaching from certain soil
surfaces such as sand and bedrock into groundwater supplies is a likely
source of contamination. Contamination of soil by irrigation is possible
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if the water is taken from a contaminated source. Improper disposal of PCB
and polychlorinated residues from this process appear to have the greatest
potential for damage.
4.3.3 Economic Factors
Since chlorinolysis has not been directly applied to PCB disposal, a
cost analysis cannot be presented at this time. Capital costs, operating
costs and possible credits have been determined for a chlorolysis plant
with a capacity to process 25,000 Mg/year of waste chlorohydrocarbons
(Wilkinson, et al., 1978). It was determined that a 15% discounted cash
flow rate of return on investment at a disposal cost of $133/Mg could be
realized. Operating and financial data are presented in Table 6.
The capital investment for facilities could be as high as $27 million
for a plant processing 25,000 Mg/year of organochlorine waste. In 1978,
the cost to destroy chlorohydrocarbons was $0.13/kg. This assumed the
present market price of CC14 was S300/Mg. (Wilkinson, et al., 1978).
It was also estimated in 1978 that about 90 to 95% of all CC14 pro-
duced was used in the production of F-ll and F-12 refrigerants and aerosols.
The future markets of these chlorofluorocarbons are uncertain because of
the chlorofluorocarbon/ozone depletion research findings. Because potential
maintenance of the CC1, market is uncertain, operating costs could be the
major issue in determining if the chlorinolysis process is a viable PCB dis-
posal method.
Overall, it now appears that the chlorinolysis process if applied to
PCB disposal would require a large capital investment and large operating
costs. A high CC1. recovery option exists, with a potential return on in-
vestment.
4.3.4 Energy Factors
In 1978, it was estimated that a 25,000 Mg/year mixed vinyl chloride
monomer chlorolysis processing plant would use 9.2 x 10 MJ of electricity
at $0.015/kw-hr, 52,000 Mg of steam at $4/Mg and 1.48 x 107m3 of cooling
water at $0.003/m . Energy credits may be available if some or all of the
heat content of the PCB waste can be recovered and used for steam produc-
tion.
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TABLE 6. OPERATING AND FINANCIAL DATA FOR A CHLORINOLYSIS
FACILITY PROCESSING 25,000 MT/YR OF ORGANOCHLORINE
WASTE (WILKINSON ET AL., 1978)
Category Quantity
Process data
Chlorine gas consumption 93,800 Mg/yr
Carbon tetrachloride produced 88,500 Mg/yr
Hydrogen chlorine produced 30,000 Mg/yr
Reactor temperature 973°K
Reactor pressure 20.2 MPa
Cost data
Depreciable investment 527,210,000
Working capital 4,708,000
Annual operating cost, including royalty 19,881,000
Revenue from CC1. and HC1 28,050,000
Unit disposal cost at 15% discounted
cash flow rate of return (DCFRR) $ 133.59/Mg
Assumptions:
Location - Gulf Coast area
CC14 selling price - $300/Mg
HC1 selling price - $50/Mg
Depreciation - 10 yr straightline
Income tax rate - 50%
Feedstock - vinyl chloride monomer wastes
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4.4 THE GOODYEAR PROCESS
4.4.1 Technical Factors
4.4.1.1 State of Technology--
The Goodyear process is well developed on laboratory level and has been
scaled up. It can only be concluded from the available literature source
that the Goodyear process is technically applicable at this time to handle
pure Aroclors or mixture of Aroclors in the 50-500 ppm concentration range.
It is claimed that significant amounts of material have been treated v/ith
sodium naphthalide reagent to reduce PCB content from 130 ppm to 10 ppm. The
process has proven to be selective and can be performed on site in existing
equipment.
4.4.1.2 System Design--
In general, the Goodyear process was developed to meet four design
criteria:
o Adaptability for complete and selective conversion of PCBs
to non-toxic products
a Capability of being performed on-site in existing equipment
a Capability of treatina small or large volumes of PCB-contaminated
fluids
Low cost
Evaluation and analysis of the specific unit processes comprising the
overall process is very difficult since scale up data are not available.
4.4.1.2.1 Pretreatment and feedTypes of pretreatment that may be neces-
sary are:
o Appropriate PCB feed rate adjustments
o Preparation of the sodium naphthalide reagent
o Solvent purification
Removal of toxic components such as trace metals or inert
constituents
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The PCS feed rate must be known in order to determine the overall
destruction efficiency. The maximum PCB input rate must be determined to
evaluate the complete feed system. The feed rate would have to be control-
led automatically to insure against over or under consumption of PCB material,
The PCB feed rate will have a tremendous effect on most other process vari-
ables.
The sodium naphthalide reagent must be prepared properly so the reaction
can be carried out as planned. Particular attention must be paid to stoich-
iometry when preparing the reagent. The mole ratios of sodium naphthalide
to chlorine must be maintained between 50-100 to remove 98% of the PCBs
from a heat transfer oil containing 83 ppm PCB (Goodyear, 1980).
Addition of the naphthalene-tetrahydrofuran solvent is critical to the
process, and must be done slowly with adequate mixing. An extremely react-
ive form of sodium must be prepared by heating pieces of sodium metal in
the heat-transfer fluid under an inert atmosphere. Temperature must remain
between 423-443°K for 5-10 minutes. This reaction is extremely exothermic,
and the solution must be cooled rapidly to ambient temperature while mixing.
The heat transfer fluid must be cleaned, and inerts or toxic components
must be removed before addition to the reactor. Any contaminant that could
react with the sodium naphthalide should be eliminated at this stage.
4.4.1.2.2 Processing--Evaluation of unit processes can only be carried out
for the scaled-up process. Lack of data prohibits an assessment of each
unit process now. Only general assumptions can be made at this time based
on available literature.
The overall reaction proceeds rapidly at room temperature. An evalua-
tion of this phase of the process should consider any possible vapor emis-
sions and the possible formation of particulates. Any excessive exotherms
or increases in temperatures should be noted in the evaluation.
If naphthalene and tetrahydrofuran are to be recovered, then an evalua-
tion of the recovery method must be done. Vacuum stripping may be the most
favorable method for recovering these components, so important variables
such as pressures and heat duties must be determined.
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Recovery of the reaction residue could be accomplished by vacuum
distillation. Important parameters that would need to be assessed are
temperatures, pressures, heat duties, and flow rates in and around the
distillation column. The pot residues from this distillation must be
analyzed to see if further processing is required.
Any other process information should also be compiled for evaluation
by the EPA Regional Administrator.
4.4.1.2.3 Pollution Control--Upon scaleup, an evaluation of all generic
effluent streams must be carried out. Vapor streams must be analyzed for
trace PCS residues as well as for chlorinated compounds and other toxic
substances. Appropriate pollution control equipment such as scrubbers,
filters, precipitators, etc., will have to be installed depending on the
nature of the pollutants. If monochloro-biphenyls are produced, then
traces of these may be contained in the vapor phase. Research is needed
to indicate whether this could occur. If a sufficient amount of low mole-
cular weight PCBs can exit as vapor, then those processes that emit the
PCBs should be sealed off, and the emitted gases should be treated. Alterna-
tively, it may be possible to reduce the PCB feed rate so that emissions are
acceptable.
Liquid effluent streams could contain dissolved solids and toxic
material which could be harmful to the environment. Appropriate pollution
control devices should be installed to eliminate these pollutants. Unre-
acted PCBs could exist in an effluent stream. Monitoring devices should
be able to detect even trace residues of unreacted PCB.
4.4.1.2.4 Destruction efficiencyIn the Goodyear study, a destruction
efficiency of 92% was achieved. Significant amounts of material were treat-
ed with the sodium naphtha!ide reagent to reduce the PCB content from 130
ppm to 10 ppm. This is below the 50 ppm lower limit for PCB contamination.
The 92% destruction efficiency still falls below those of Annex I inciner-
ators or high efficiency boilers.
4.4.1.3 Process Controls
An evaluation of process controls should include temperature control,
pressure control, flow rate control, and any other necessary controls to
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enable the process to operate efficiently and safely.
Temperature is an important variable which will affect the overall
PC8 destruction efficiency and reaction rate. The PCB reaction with the
sodium napthalide reagent is highly exothermic and must be adequately con-
trolled. Temperature sensing devices would need to be installed to indi-
cate any extreme increases in temperature or heat intake. Any heat ex-
changers used in the process should be controlled to guard against unwar-
ranted temperature deviations.
Pressure will need to be controlled in the reactor and in any other
processing equipment where pressure drops could affect the performance of
the system. Compressors, pumps,and any other accessory pressure equipment
must be controlled sufficiently.
Flow rates of all streams must be monitored and controlled. Flow
rate is a critical variable affecting the overall performance of the pro-
cess. The feed stream may be the most critical of all the streams that
will need to be controlled. The feed rate will depend on the amount of
PCBs contained in the stream.
Likewise, all pretreatment equipment and pollution control equipment
must contain adequate process control devices to regulate important oper-
ating variables. A detailed analysis of required process controls cannot
be carried out at this time without scaleup operational data.
4.4.1.4 Effluent Monitoring
Lack of process information prohibits a detailed assessment of efflu-
ent monitoring demands for the Goodyear Process. Only general guidelines
may be presented at this time.
The Regional Administrator will evaluate the capability of the facility
operator to monitor all important process effluent streams. The facility
operator must describe all important process streams so a decision can be
made about which streams should be monitored and what type of monitor
should be used. In general, gaseous streams should be monitored and sampled
periodically for both PCBs and other chlorinated compounds. Waste gases are
not expected to be of major importance in the Goodyear Process,so sampling
and monitoring them should pose no problem.
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Liquid effluent streams from all sources should be monitored for PCB
content and for other toxic or hazardous components including dissolved
solids. Plant data concerning the stream should be logged and kept for
future reference. Tap sampling may be used for liquids in motion or static
liquids in tanks or drums. Automated samplers should be used to increase
the chance of collecting a representative sample.
Solid waste streams should be sampled by a grab technique. Analysis
for PCB and residual chlorinated hydrocarbon content of these streams should
be performed. The location of solid sampling locations should depend on
the ability to collect a representative sample.
4.4.1.5 Waste Characterization--
4.4.1.5.1 Range of PCB concentrationThe Goodyear Process seems best suit-
ed to handle heat transfer fluids with PCB concentrations in the range of
50-500 ppm. The process may also be able to handle transformer fluids with
PCB content greater than 500 ppm. More research is needed to determine the
maximum concentration of PCBs that the process can handle.
4.4.1.5.2 Limitations on constituents--PCB wastes containing excessive con-
centrations of toxic heavy metals or containing inert substances will re-
quire pretreatment prior to entering the reactor. The type of treatment
will depend on the nature of the materials to be eliminated.
4.4.2 Environmental Factors
Because very little information exists on disposal of PCBs by the
Goodyear Process, it is extremely difficult to estimate environmental im-
pacts. Environmental factors must be researched in detail upon scaleup
of this process.
4.4.2.1 Potential Impacts of Disposal Operation--
It appears that minimal environmental impacts would be expected from
the Goodyear Process. Since the chlorinated biphenyl content can be lowered
to 10 ppm, environmental damage does not appear likely. There is a possi-
bility that PCBs could be released to the ambient air but their content
should be small. Trace amounts of unreacted sodium metal, naphthalene, and
tetrahydrofuran could be released in liquid effluent streams. The chance
of this seems minimal, since recycling and reprocessing could be used to
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recover these substances for reuse.
4.4.2.2 Potential Impacts of Disposal of Process Wastes--
The bulk of residual PCBs would be expected to be contained in the
processed heat transfer fluid. This fluid could be recycled or reused
directly so there is no real impact from this waste. Lower weight chlori-
nated biphenyls may exit as vapor from various process steps, but their
concentration should be 10 ppm or lower. If any auxiliary processes are
used to eliminate PCB residues or volatile organics, such as incineration
or wet air oxidation, the potential environmental impact will increase.
The possibility of other toxic or harmful substances being eliminated in
waste streams such as HC1, trace metals, and chlorinated compounds should
be determined in the scaleup study. Overall, the potential impacts of the
disposal operation on the environment appear to be low although a thorough
assessment cannot be made without the appropriate data.
4.4.2.3 Potential Impacts of Accidents--
It is very difficult to predict the potential impacts of accidents at
this time. A spill or release of PCBs from the Goodyear Process could
possibly result in contamination of surface groundwater through seepage;
contamination of land areas where humans, animals, or croplands are exposed;
and contamination of areas that could create airborne movement of PCBs.
Leaks or spills of other materials such as naphthalene, tetrahydro-
furan, sodium, and various byproducts could also cause some environmental
damage. The extent of this possible damage must be assessed. Spill pre-
vention and control procedures must be developed pursuant to EPA regula-
tions. Because of the possible threat to the environment, the facility
using the scaleup version of the Goodyear Process must address all aspects
of accident prevention. The process should be evaluated according to EPA
regulations covered in Section 2 of this report.
4.4.3 Economic Factors
The following quantities of materials were recommended for the reagent
preparation and in the large scale treatment of a heat-transfer fluid con-
taminated with 82 ppm of chlorinated biphenyls. Quantities are given per
1 kg (2.2 Ibs) of fluid to be treated. The prices quoted are given in the
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"Chemical Marketing Reporter," April 2, 1979.
"odium Metal -^- S/kq (2.2 Ib) S/100 kg (220 Ibs)
.oaiurn neta i Q<(J5 K4] g-^
Heat-Transfer Oil 0.50
Naphthalene 0.32 0.79 0.557
Tetrahydrofuran 0.89 1.89 3.69
2.0025
No credit for the recovery of naphthalene or tetrahydrofuran was
considered in developing these material costs. With large scale applica-
tion of this process, product recovery may be economically feasible.
Generally, the Goodyear Process appears to be relatively low in cost
and may be adaptable to both small or large scale operation. A detailed
economic evaluation will need to be performed before this process may be
judged economically justified.
4.4.4 Energy Factors
Available information from the Goodyear Tire and Rubber Company did
not include any data about energy requirements. The amount of energy re-
quired per unit weight of PCB converted must be determined in the overall
assessment. It should be determined whether some or all of the heat con-
tent of the PCB waste may be recovered to produce steam for an energy cre-
dit. Further assessment of energy factors cannot be carried out at this
time. However, the Goodyear Process does not appear to consume a large
amount of energy per unit weight of PCB converted.
4.5 MICROWAVE PLASMA
4.5.1 Technical Factors
4.5.1.1 State of Technology--
A 15 k'/\l microwave plasma reactor system capable of destroying 2 to 11
kg per hour of organic wastes including PCBs is now in operation.
4.5.1.2. System Design
4.5.1.2.1 Pretreatment and feedSpecial operations are necessary for dis-
pensing the feed into the reaction zone. Gases and volatile liquids must
be handled differently. The feed must be dispensed from its reservoir at
atmospheric pressure or greater into a reduced pressure environment of about
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6,000 Pa. Reduced pressure in the plasma reactor can be used to pull the
liquid through a needle valve below the reservoir. Liquid feed can also
be introduced by using a peristaltic pump that controls the flow of liquid.
The feed must uniformly fill the reactor cross section. The liquid must
either be dispensed directly to the plasma or can be flashed to vapor
before delivery to the plasma. The throughputs of the reactor will be
limited by the feed system and not by the plasma's ability to detoxify the
reactant. Constituents that could cause corrosion or interfere with the
microwave processes must be removed before entrance into the reactor. Con-
ventional pretreatment systems such as filtration, evaporation, absorption,
etc., could be used.
4.5.1.2.2 ProcessingReactor design is of critical importance. The reac-
tor tube must have the proper dimensions to prevent leakage of the micro-
waves out of the applicator where the reactor tube enters and exits. The
reactor tube must be in a vertical position to allow liquid feed to flow
directly into the plasma without contacting the walls of the tube. Thermal
degradation or charring could occur in this zone if the liquid is allowed
to contact the walls of the tube. If a nonvertical reactor must be used,
a jet or nozzle should be used to squirt the liquid feed into the reactor.
The reactor must be transparent to avoid overheating by absorption of micro-
wave energy and must have high thermal shock resistance to avoid breakage
when 15 kW of microwaves suddenly heat the packings or gases to high temper-
atures. It is also critical that the reactor tube be transparent to infra-
red and visible radiation to allow for radiative cooling of the hot gases
and packings. Attention must be paid to construction materials. Material
that will not shatter when heated rapidly in the microwave fields must be
used. In several reactor designs, quartz was found to be the only material
capable of withstanding the severe conditions in the plasma. Critical pro-
cess parameters are: microwave power density, plasma length, PCB feed rate,
and oxygen/PCB ratio.
4.5.1.2.3 Pollution control--The effluent gases leaving the plasma are
extremely hot, corrosive and will contain large amounts of chlorine. The
effluents will need to be treated to lower the temperature and to remove
acid products. Radiative heat exchangers should be used to cool the pro-
cess effluents. Acid products must be removed in a caustic scrubber. The
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caustic will have to be replaced periodically as it is consumed by the re-
actions with the acids.
4.5.1.2.4 Destruction efficiencyIt has been determined on a laboratory
scale that the destruction efficiencies of Aroclor 1242 and Aroclor 1254
are 99%, using 4.6 and 4.5 kW microwave power respectively. (Hertzler et
al, 1979).
4.5.1.3 Process Controls--
The process control system for a 15 kW microwave plasma reactor sys-
tem is extremely complex. The cooling water required by the microwave
power supplies must be automatically turned on whenever the microwave con-
trol circuits are turned on. An induced draft fan must be used to pull
cooling air through the microwave power application and around the quartz
reactor tube. Pressure in the reactor must be regulated. If the pressure
rises too high, the oxygen flow, the reactant feeder, and the microwave
power output would be shut off. If the plasma were extinguished while the
microwave power were being applied to the reactor, the oxygen flow and the
reactant feed would be shut off. A low pressure switch should be activated
if the caustic recirculation pump on the caustic scrubber fails. This will
shut off the fan on the scrubber, and,as a consequence, the pilot tube sen-
sor on the scrubber inlet would sense the loss and activate an annunciator.
4.5.1.4 Effluent Monitoring--
The effluent gases leaving the plasmas are hot (up to 2000°K), corro-
sive (often containing large amounts of chlorine), and under a vacuum.
Monitoring will be required to lower the temperature and remove acid pro-
ducts from the gases. Process effluents exiting the plasma must be cooled
and then compressed to atmospheric pressure. It is important that the pro-
per types of heat exchangers and vacuum pumps be used for this process.
Traditional rotary oil-seal vacuum pumps would very quickly become contami-
nated with acid products and clogged with water condensed during the com-
pression.
The caustic scrubber on the vacuum pump exhaust removes acid products
by passing the gases through a bed sprayed with caustic. Caustic is lost
by reactions with the acids and must be monitored and replaced.
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The amount of any residual reactant leaving the plasma should be moni-
tored for and analyzed. Gases leaving the plasma should be sampled by using
conventional methods based on drawing the gas through a tube packed with
adsorbent that collects the components of interest.
It must be remembered that the purpose of effluent monitoring is to
determine the extent of PCB degradation and to assess the potential environ-
mental impacts of undestroyed PCBs and any other toxic or hazardous material
contained in the effluent stream. To meet this requirement, careful efflu-
ent monitoring at all important entrance and exit points to process equip-
ment should be applied.
4.5.1.5 Waste Characterization--
4.5.1.5.1 Range of PCB concentrationThe process should be able to handle
PCB concentrations within the 50-500 ppm range effectively. Further,
research needs to be done to determine the maximum concentration of PCBs
that can be destroyed with a high destruction efficiency.
4.5.1.5.2 Limitations on constituentsAny constituent that will interfere
with the microwave process or that could cause extreme corrosion of reactor
equipment should be eliminated. It is important to note that as the number
of chlorine atoms on the PCB molecule increases, the destruction efficiency
decreases.
4.5.2 Environmental Factors
4.5.2.1 Potential Impacts of Disposal Operation
An environmental assay of the disposal operation must consider: the
shipment and handling of the PCB prior to processing, control of the poten-
tial gas and liquid effluents after conversion, and handling and storage of
the final products. Possible leaks from the caustic scrubber system must
be controlled.
4.5.2.2 Potential Impacts of Disposal of Process Hastes
Though microwave plasma degradation is a controllable method which
yields innocuous products like C02 and H20. Potentially hazardous products
like CO, and chlorides will also be produced. The Cl^ could possibly show
up in rivers and municipal water systems. Particulate matter emissions do
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not appear to pose any significant threat to the environment. The use of a
caustic scrubber should keep emissions fairly low. Since the waste efflu-
ent streams are mainly liquid, any solid emissions would be dissolved in
the liquid effluent as suspended particles. The liquid effluents should be
discharged to a municipal sewage system after treatment. Any contaminants
from the scrubber process would be contained in the sludges generated by
the municipal waste treatment system.
4.5.2.3 Potential Impacts of Accidents--
To insure safe operation of the plasma microwave reactor system, a
series of interacting safety circuits that automatically shut off the unit
or warn the operators if certain process parameters are not in the safe
range should be installed. These should include the following:
If the water flow rate to the water ring seal vacuum pump is in-
sufficient, it should activate an annunciator.
If the temperature of the gases entering the shell and tube
heat exchanger approach the critical temperature where the
heat exchanger coating could be damaged, an annunciator should
be activated to warn the operators.
Extremely high temperatures and pressures occur throughout the system.
The potential for accidents should be an important variable entering into
the process design. Accidental spills and leaks of both solid and liquid
wastes could be the primary source of accidents. These spills and leaks
could be minimized by conventional prevention methods.
4.5.3 Economic Factors
Very little information exists on the economics of a microwave plasma
process adapted to PCB detoxification. The apparatus has a potential ad-
vantage of being made into a mobile unit, with a relatively low initial
cost. The following calculations will need to be made in estimating the
net profit per kilogram of PCB destroyed by the microwave plasma unit:
Electrical costs
Liquid oxygen costs
Steam costs
Labor costs
0 Available credits from recoverable products
e Capital costs
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Overall capital costs for PCB detoxification may be high since useful
byproducts may not be recoverable. A rough cost of S0.44/kg of PCB process-
ed has been determined for oxygen and steam plasmas. (Wilkinson, et al.,
1978) in 1978. Electrical costs should decrease as microwave power tech-
nology advances. Improvements in basic plasma design should cut operating
costs substantially. Overall cost for a mobile unit will also depend in
part on the distance to the user's site and the concentration of PCBs to be
removed from the heat transfer material. At this time, it appears that a
large scale microwave plasma detoxification unit will moderate capital in-
vestment and operating costs.
4.5.4 Energy Factors
A detailed literature search uncovered very little information about
the energy requirements of this process. Since microwave plasma destruc-
tion uses energy from free radical reactions rather than energy derived
from heat or molecular motion, the entire reaction zone may operate just
slightly above room temperature. This may lower the energy costs slightly
and is an important factor to consider when evaluating the energy efficiency
of the process. Large amounts of energy may be needed to drive the micro-
wave reactions, so the energy demand for this process must be examined very
carefully. The possibility of recovering waste heat for steam production
should be assessed, as this could provide a substantial energy credit.
4.6 OZONATION PROCESSES
4.6.1 Technical Factors
4.6.1.1 State of Technology--
UV-Ozonolysis has proved to be an effective method for the destruction
of PCBs in industrial waste water on the laboratory level only. Scaleup
to pilot plant level has not been attempted.
4.6.1.2 System Design--
4.6.1.2.1 Pretreatment and feedUntreated water samples containing PCBs
will also contain other components in trace amounts that could react with
the UV radiation and with the ozone. Precautions must be taken to elimi-
nate as many of these constituents as possible. Filtration, evaporation,
carbon adsorption, or any other suitable pretreatment method should be used
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to eliminate these contaminants before exposure to the UV radiation and
ozone.
4.6.1.2.2 Processing--Important operating variables include: ozone flow
rate, ozone concentration, UV intensity, and residence time. Batch tests
need to be carried out to determine the effect of each one of these vari-
ables on the degree of destruction of the PCB molecule. Batch tests are
also needed to determine the UV-ozone reactor size, the ozone generator
output requirements, and the affect of UV light on the rate of oxidation.
Reaction conditions should be varied to determine the utility of this
method to destroy PCBs. Oxone is produced from liquid oxygen in an ozone
generator. The reactor will emit gases which should be passed through a
thermal decomposer to break down the ozone before being discharged. It is
extremely important to provide an effective heat transfer surface for the
ozone in the thermal decomposer. Since ozone decomposes above 440°K,tem-
peratures above this must be generated. The thermal decomposer must be
made of stainless steel and packed with stainless steel wool. Ozone is
extremely corrosive, so care must be taken to use proper material in all
the processing equipment that the ozone will contact. PCBs have an ex-
tremely low vapor pressure, and would not be expected to evaporate quickly.
Their low solubility in water will make them fairly susceptible to removal
by sparging.
4.6.1.2.3 Pollution control--Pollution control devices must be installed
to monitor and rectify gases given off from the reactor. These gases may
contain some ozone, CO^, CO, and possibly some simple chlorinated species.
The UV-ozone reactions need to be studied further to determine the exact
nature of the wastes given off so adequate pollution control devices can
be installed.
4.6.1.2.4 Destruction efficiencyThe destruction efficiency is defined
as:
DE = 100 (PCBin " PCBout )
PCBin
Substituting values from one of the experiments carried out by General
Electric Corp. gives a destruction efficiency of approximately 93% + 3%.
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It is important to note that the PCB concentrations were in ppb.
4.6.1.3 Process Controls--
Temperature, pressure, flow rate, liquid level, and pH must be moni-
tored and controlled throughout this process. In order to achieve the re-
quired degree of process control, these variables must be defined complete-
ly. Suitable controllers must be chosen to manipulate these variables.
The temperature in the reactor must be controlled for the reaction to pro-
ceed properly. Pressure must be controlled in the ozone generator. All
flow rates to and from the reactor must be monitored and controlled to in-
sure the correct stoichiometric amounts of reactants. The liquid level in
the reactor must be controlled to guard against overflow. The reaction
solution must also be at the proper pH. Ozonolysis can only occur within
a specific pH range, so it is vital that pH should be controlled.
4.6.1.4 Effluent Monitoring--
Because UV-ozonolysis appears to be best suited for removing PCBs from
dilute aqueous streams, effluent monitoring should be conventional in nature.
Extensive routine monitoring for water quality parameters should be taken in
order to determine the composition of all waste water streams. Gaseous emis-
sions of PCBs would best be sampled by using high volume ambient air samplers
modified with polyurethane foam as an adsorbent (Stratton, et al., 1978). All
the air sampling instruments used should have a high demonstrated efficiency
under field conditions. The monitoring instruments should be able to de-
tect very dilute amounts of ozone carbon monoxide, and simple chlorinated
species. Conventional monitoring devices such as chromatographs and spec-
trometers could be used to help regulate effluent composition. If a scrub-
ber is used to eliminate chlorinated compounds such as HC1, its effluent
should be monitored for trace quantities of hazardous materials. The oper-
ator of the facility should list and describe the various streams that will
need to be sampled. Tap sampling should be used to monitor flowing liquids
and liquids in tanks or drums.
4.6.1.5 Waste Characterization--
4.6.1.5.1 Range of PCB concentration--PCB concentrations handled by the
various laboratory processes have ranged from 30 ppb to 100 ppb in aqueous
solution.
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4.6.1.5.2 Limitations on constituentsAny material that could interfere
with the UV-ozonolysis process should either be eliminated or minimized.
Many contaminants will not react with UV radiation. Some of these may
prove to be toxic would be introduced into the atmosphere along with
the vent gases. Alternatively, some constituents could react with the UV
radiation and ozone to create undesirable products. Because of this, the
wastewater feed should be limited to only those constituents that can safe-
ly react with the ozone and UV radiation. More research is needed to deter-
mine the limitations on constituents to such a system.
4.6.2 Environmental Factors
4.6.2.1 Potential Impacts of Disposal Operations--
Shipment and handling of the PCB wastes prior to UV-ozonolysis must
be included in an environmental evaluation. The process facility might
not be located on the same site where the PCB wastes are produced. An
assessment of shipping risks and handling procedures should be carried out.
Methods for handling and storage of the final products must also be carried
out. Some of the products might be toxic or corrosive. An assessment of
types of final products that will be produced as well as equipment necessary
to handle them will be necessary. Any auxiliary disposal operations such
as adsorption, filtration,or incineration, must be analyzed for possible
environmental damage.
4.6.2.2 Potential Impacts of Disposal of Process Wastes
The possibility of reaction products being formed which are harmful
to aquatic life must be considered. Residual amounts of halogenated com-
pounds as well as trace metals may be contained in the waste effluents.
These products could possibly accumulate in aquatic organisms. Vent gases
may also contain toxic or harmful substances. Various chlorinated compounds
as well as other toxic substances could accumulate either in the atmosphere
or on land.
4.6.2.3 Potential Impacts of Accidents--
Accidental spills and leaks of both solid and liquid wastes are the
primary sources of accidents. Precaution against UV radiation and ozone
leaks must be taken. Implementation of available control technology will
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make it possible to minimize PCB loss during transfer, storage, and dispos-
al. A spill or release of PCBs from a UV-ozonolysis facility may pose the
following threats:
t Contamination of surface or groundwater
Contamination of land areas where humans, animals or croplands
are exposed
Contamination of areas that could lead to significant airborne
movement of PCBs.
As noted in Section 2.1, regulations pursuant to the Clean Water Act
currently require facilities disposing of PCBs to prepare spill prevention
control and countermeasures plans. These plans should detail safe handling
procedures for hazardous materials including PCBs. They also should ad-
dress prevention and control procedures when a release of PCBs occurs.
An adequate SPCC plan should minimize the potential for spills, and there-
fore potential environmental impacts should be reduced.
4.6.3 Economic Factors
A large scale "Ultrox" UV-ozone processing plant is now operating at
the Iowa Ammunition Plant in Brislington, Iowa. Approximate costs have
been determined and are as follows:
Maximum capacity 567 m /day
Average output 567 m /day
Lease term 3 years
Installation $12,000
Annual Lease $87,359
Additional Charges $32,820
Power and Labor $52,260
Total Operating Cost per year $172,439
Treatment cost per m3 $ 0.87
(264.5 gal)
These costs were determined in 1979 and will need to be adjusted to
current rates. Principal capital equipment costs will be the reactor,
ozone generator and power supply, and the UV irradiation source and power
supply. Principal operating costs include electrical energy and labor.
In general, UV-ozonolysis should be cost competitive if applied to dilute
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aqueous PCB solutions on a large scale. An economic analysis should also
consider whether or not it is possible to obtain credit for products or by-
products. Expected costs of closure and post closure monitoring and main-
tenance should also be determined.
4.6.4 Energy Factors
The amount of energy required per unit weight of PCB waste destroyed
is a critical factor in determining whether or not the process is viable.
An extensive literature search could not uncover any information dealing
with energy requirements for UV ozonolysis. An assessment must be made to
determine overall energy debits and credits, such as the possibility of re-
claiming the heat content of the PCB waste to produce steam.
4.7 PHOTOLYTIC PROCESSES
4.7.1 Technical Factors
4.7.1.1 State of Technology--
Photochemical destruction of organic material has not been applied on
a large scale, and has rarely been directly applied to the degradation of
PCBs. Success has been achieved in the laboratory with various classes of
dioxins and other toxic pesticides.
4.7.1.2 System Design--
Because photolytic processes have rarely been applied to PCB degradation
and are on the laboratory scale only, a direct analysis of the technical
factors affecting system design is very difficult. Only assumptions can be
made at this time. Important questions that must be considered for the
overall system design include:
o How rapidly do photochemical reactions occur?
o What energy input is necessary?
o What products will be formed, and how are these products
affected by the physical state of the reactants?
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4.7.1.2.1 Pretreatment and feed--Laboratory research studies have used
mono-, di-, tri-, and tetrachlorinated biphenyls in the photolysis studies.
The PCBs have been purified by recrystallization from ethanol. Industrial
scale up would require adequate pretreatment to eliminate any material from
the feed stream which could interfere with the photochemical reactions.
Contaminants that could lower the solubility of the PCBs would also need
to be removed by a suitable pretreatment process.
Currently, photolysis has not been tried on a RGB-contaminated trans-
former or capacitor fluid. The effect of the numerous PCB isomers on the
degradation process needs to be investigated to determine limiting feed
characteristics such as composition and flow rates.
4.7.1.2.2 Process ing--Intensive studies need to be carried out to determine
how useful ultraviolet radiation is in decomposing PCBs. The rupture of a
chemical bond requires a certain amount of energy. The dissociation of a
carbon-carbon bond requires an input of about 418.4 kJ/mol. Light possess-
ing at least this amount of energy must be used. The source must provide
a reasonable amount of energy at low wavelengths. A medium pressure mercury
arc lamp meets this requirement. Its maximum energy distribution is around
254 nm. It is important that the lamp be contained in a quartz housing to
allow the passage of lower wavelengths. If photolysis is to occur at all,
the PCB molecule must first absorb light energy above 290 nm or receive
energy from another molecule through an energy transfer process. A study of
the process must try to determine the structure of the resulting photo-
products, the effects of solvents on product formation, reaction rates, and
the relationships between PCB structure and the rate of photolysis. The
three most important processing variables which must be controlled are: a
hydrogen-donating solvent must be present, UV light of the correct wave-
length must strike the solution properly, and this light must be absorbed.
Choice of solvents is also a critical factor. The PCB material must be in
liquid form, so any solid material must be put into solution. Photochemical
studies of PCB degradation are minimal. The emphasis has been on irradiating
the PCB material at 300 nm in different solvents such as methanol and hexane
for different time periods. The photoproducts are analyzed, and mechanistic
pathways are theorized. Not all process parameters needed to establish
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photolysis as a viable process for PCB degradation have been defined, and any
discussion of them would be purely speculative.
4.7.1.2.3 Pollution controlIntensive studies need to be carried out to
determine the final products, including by products and residuals, before the
question of pollution control can be addressed. The effluents resulting
from photodecomposition may be complex mixtures containing toxic and corro-
sive compounds. The current data base prohibits even a qualitative assess-
ment of what types of control devices would be necessary for pollution con-
trol. Typical pollution control equipment such as scrubbers and adsorption
towers would not be easily adaptable to the photolysis process if adverse
pollution effects are found to occur.
4.7.1.2.4 Destruction efficiencyDestruction efficiencies as such have not
been determined for the laboratory PCB reactions. A 90-95 percent yield of
dechlorinated PCB in methanol solution has been determined in the experiments
done by Ruzo (Ruzo, et al., 1974). Methanol substitution products were also
found in these experiments.
4.7.1.3 Process Controls--
Elaborate process controls would be necessary to control flow rates,
temperatures, pressures, and UV intensity upon scale up. Flow rates of all
incoming the outgoing streams would need to be monitored and controlled.
Temperature in the reactor must be controlled to provide adequate reaction
conditions. Pressure drops through any process equipment such as heat
exchangers, compressors, or pumps must be controlled. Only UV radiation of
certain wavelengths should be allowed to penetrate the reaction solution.
This can be controlled by using the proper UV light source along with appro-
priate filters. Safety control circuits regulation the UV power supply would
have to be installed to insure against over exposure of the reaction solution
to the UV radiation. The specific types of controllers and where they should
be located in the process scheme cannot be predicted until scale up studies
are done.
4.7.1.4 Effluent Monitoring
As stated earlier, photolysis used as a destruction method for PCBs
has barely been researched at this time. The breakdown and analysis of all
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possible effluent waste streams has not been done. Since the effluents from
this process could be complex mixtures of extremely toxic and corrosive
compounds, an assessment of the types and locations of monitoring devices
would be an integral part of scale up operations. Careful effluent monitor-
ing will be needed to determine the extent of PCB conversion and to determine
the potential environmental impacts of any undestroyed PCBs or any other
hazardous material.
Liquid effluent streams must be monitored for PCB content and for the
occurrence of HC1 and other chlorinated compounds. Periodic samples from
all waste streams should be analyzed for content in a laboratory. Any vent
gases should be monitored by using ambient air samplers. Periodic air
samples must be collected and analyzed for PCB content and overall composi-
ti on.
The effluent monitoring capability of a photolysis treatment facility
is determined by the facility operators' description of the appropriate
streams to be sampled. Prior to sampling any effluent stream, plant data
concerning that stream must be available. Overall, effluent monitoring
should be automated. Units are readily available and capable of monitor-
ing the complex effluents generated by the photolysis process.
A data base must be developed before a detailed assessment of viable
effluent monitoring schemes can be developed.
4.7.1.5 Waste Characterization
4.7.1.5.1 Range of PCB concentrationThe photolysis process may be appli-
cable over a wide range of PCB concentrations. The process should v/ork for
dilute solutions as well as for PCB concentrations greater than 500 ppm.
The important factor determining the concentration range of the PCBs is its
solubility in the solvent. Research has not been done on an actual PCB min-
eral oil, so the applicability of this process to the real life situation is
not completely validated.
4.7.1.5.2 Limitations on constituentsAny component in the feed stream
which could react with the PCBs and UV radiation should be eliminated by
pretreatment. Particulate matter and nondissolvable solids should either
be eliminated or reduced by pretreatment. Any constituent that could cause
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corrosion or fouling of any of the process equipment must be removed. Pre-
sently, it is not known which substances could interfere with the photolysis
process.
4.7.2 Environmental Factors
4.7.2.1 Potential Impacts of Disposal Operation
The overall disposal operation is underdeveloped. Basic environmental
impacts must be outlined before an empirical assessment of the disposal opera-
tion can be determined. Possible hazards will include the shipment and hand-
ling of the PCBs prior to photolysis, control of the potential gas and liquid
effluents after conversion, and handling and storage of the final products.
Each one of these areas must be researched in the environmental assessment.
Shipment and handling of the PCBs do not pose any real risks if appropriate
safety regulations are followed. Control of the various effluents will depend
on the nature of the effluents. Research is needed to determine the possible
composition of each stream in the process so the overall impacts from the dis-
posal operation can be determined. Handling and storage of the final products
can be accomplished safely by using standard safety precautions.
4.7.2.2 Potential Impacts of Disposal of Process Wastes
The precise chemical nature of the process wastes will need to be investi-
gated heavily before assumptions about process waste disposal can be made.
Progress in identifying all the possible side products of PCB photolysis has
been extremely slow. Because the mineral oil may contain numerous isomers of
the PCB molecule, process waste characterization is very difficult. Certain
chlorinated compounds may exist in the waste streams that could be harmful to
the environment. Gaseous effluents could contain hydrochloric acid and photo-
active compounds. Aqueous effluents could contain chlorine and possible com-
ponents that did not react with the UV radiation. These substances could re-
act further, creating either toxic or inert compounds which could cause environ-
mental damage.
4.7.2.3 Potential Impacts of Accidents--
Accidental spills and leaks of solid, liquid, and gaseous wastes are the
primary sources of accidents. These can be minimized by standard preventive
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procedures. Solid wastes may contain toxic substances that could percolate
into the soil and have damaging effects on irrigation and water consumption
sources. Liquid wastes may contain dissolved solids and toxic substances
that could cause problems for aquatic or marine organisms. Aquatic toxicity
tests will be required to determine the impact of aqueous wastes on aquatic
and marine organisms. Overall, the potential for accidents will need to be
assessed upon scale up, since laboratory studies alone cannot forecast pos-
sible emergency situations that could occur in an industrial situation.
4.7.3 Economic Factors
To date, the economic impacts of the large scale application of photo-
lysis have not been determined. Some of the factors that will affect over-
all capital and operating costs include: land availability and cost, types of
chemicals and reagents required, labor, monitoring, application costs, etc.
Photolytic degradation of PCBs must be researched further in both laboratory
and field studies before an economic evaluation of this technology can be
carried out. Based on the limited information available, scaled up operating
and capital costs appear to be moderate. Possible economic credits could be
gotten if some of the products are saleable or reuseable. This must be de-
termined in further laboratory studies.
4.7.4 Energy Factors
Because photolytic degradation of PCBs has barely been researched in the
laboratory and has not been applied on an industrial scale, energy usage can-
not be determined. The amount of energy consumed per unit weight of PCB de-
stroyed will need to be determined as an energy debit. Energy credits may be
earned if some or all of the heat content of the PCB waste can be recycled to
produce steam.
4.3 REACTION OF PCBs WITH SODIUM, OXYGEN, AND POLYETHYLENE GLYCOLS
4.8.1 Technical Factors
4.8.1.1 State of Technology
The use of molten sodium metal dispersed in polyethylene glycols to
degrade PCBs has been accomplished effectively on the laboratory scale only.
4.8.1.2 System Design--
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4.8.1.2.1 Pretreatment and feedComponents in the feed stream that could
interfere with the main reaction between the PCB oil and the molten sodium
metal must be removed by appropriate pretreatment processes. The reaction
is highly exothermic so any contaminants that could cause extreme tempera-
ture variations or side products should be eliminated prior to processing.
Constituents that could decrease the solubility of the PCB oil in the sol-
vent should also be removed or degraded by pretreatment.
4.8.1.2.2 Process ing--Important process variables need to be defined before
scale up is attempted. Particular attention must be paid to temperatures and
stoichiometry. The temperature in the reaction vessel must be raised above
the melting point of the metallic sodium (370.28°K). Adequate mixing of the
reaction mixture of polyethylene glycol and PCB oil must be achieved to pro-
vide a uniform dispersion. Cyclohexane or any other appropriate solvent must
be used to extract the organic components out of the solution. The melting
of the sodium in the polyethylene glycol must be done in an oxygen free en-
vironment. When air is later allowed into the system, a vigorous, exothermic
reaction will occur. A large amount of hydrogen gas will be emitted. It is
important to note that only in the presence of oxygen will the molten sodium
react with all the glycolic solvents. Dechlorination will not occur in non-
polar low volatility liquids, in glycolic solvents where both terminal hy-
droxyl groups are replaced with alkoxy groups, or in glycols in the absence
of air.
4.8.1.2.3 Pollution control--Large amounts of MaCl and hydrogen gas will
be evolved in this process. The hydrogen gas must be drawn off and could be
collected as a valuable source of energy. Also, with scale up, the large
quantities of NaCl produced would not create any special disposal problems.
The recovered hydrogen gas could be used as an additional source of energy
to melt the NaCl. Containment and removal of any other residual wastes should
be an important consideration in scale up studies. Appropriate pollution
control equipment would have to be installed to meet government regulations.
Any waste gases would have to be either removed in an absorption unit, by
any other appropriate method, or recycled for reuse. Further laboratory
studies are needed to determine the precise composition of the waste gases.
4.8.1.2.4 Destruction efficiencyLaboratory studies have indicated an
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approximate 95 percent conversion of the PCB oil. Precise destruction effic-
iencies have not been determined.
4.8.1.3 Process Controls--
Upon scale up, emphasis must be put on process control. Extreme heat
is generated by the addition of the sodium metal. This heat must be moni-
tored and controlled with appropriate temperature controllers. Various types
of control circuits may have to be installed for both safety and monitoring
purposes. Flow rates of any waste gases, particularly hydrogen, must be regu-
lated. Flow rates of each stream should be monitored and adjusted to meet
process conditions. It is extremely important that the pressure in the re-
actor and any other processing equipment be maintained within the optimum
operating range. Pressure valves and controllers must be installed to con-
trol pressure drops through the heating elements and to control abnormal
pressure deviations. Liquid levels in the reactor and storage tanks must be
monitored for overflow and to insure a free flow throughout the process.
4.8.1.4 Effluent Monitoring--
As stated earlier, the reaction of molten sodium with polyethylene gly-
ri
cols will produce large amounts of hydrogen gas. It is critical that the pre-
cise amount of gas evolved be determined so appropriate safety devices should
be placed at strategic locations to monitor critical paramters such as temper-
atures, pressures, and flow rates. Ambient air samplers can be used to moni-
tor the hydrogen and any other evolved gases. Effluent streams which contain
the polyhydroxylated biphenyls must also be monitored. These compounds may
prove to be toxic to humans or animals in the immediate vicinity of the pro-
cessing facility. Streams containing NaCl should also be monitored for the
existence of dissolved solids and possible toxic compounds. Though effluent
monitoring is important, it is possible that the recovered hydrogen gas could
be used as a source of energy to melt the NaCl and, using electrolysis tech-
niques, reduce it to sodium metal and chlorine gas. This process would de-
crease the importance of monitoring although recycling would have to be
carefully engineered.
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Liquid effluent streams must be monitored for PCS content and for the
existence of HC1 and other simple chlorinated compounds. Standard monitor-
ing devices may be used to examine periodic samples from each effluent
stream. A careful analysis of all effluent streams must be carried out if
this process is to be commercialized.
4.8.1.5 Waste Characterization
4.8.1.5.1 Range of PCS concentrationsThe process appears to be applicable
over a wide range of PCB concentrations, particularly in the range from
50-500 ppm. The process could also be effective for concentrations greater
than 500 ppm.
4.8.1.5.2 Limitations on constituentsAny constituent that will either
interfere with the molten sodium reaction or that will decrease the solu-
bility of the PCBs should be eliminated before processing by appropriate
pretreatment.
4.8.2 Environmental Factors
4.8.2.1 Potential Impacts of Disposal Operation--
Potential hazards from the disposal operations are hydrogen gas leaks
and storage and handling of the hydrogen gas and any residual PCBs. Hydro-
gen gas is highly flammable and common sense safety measures should be used
to avoid costly accidents when reprocessing it. Transportation and storage
of the PCBs can pose impacts. Standard preventive procedures should be used
to prevent leaks and spills, both before and during processing.
4.8.2.2 Potential Impacts of Disposal of Process Wastes--
Direct disposal of NaCl does not pose any serious problems. The large
quantity of hydrogen gas evolved should be recovered and reused as a source
of energy to melt the NaCl. The hydrogen gas could possibly be used to
reproduce the sodium metal by using electrolysis techniques. This could
result in a recycling of the sodium metal and chlorine gas. Polyhydroxy-
lated biphenyls are also produced by the reaction. These are useful com-
pounds that could be sold and used as antioxidants in foods or in the pre-
paration of various types of polymers.
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4.8.2.3 Potential Impacts of Accidents--
The evolution of large amounts of hydrogen 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. Since the reaction with sodium metal is extremely exo-
thermic, heat must be continuously removed from the reaction vessel. Cau-
tion must be taken to insure against extreme temperature rises in the re-
actor. Improper handling of the PCBs during shipping and storage could
cause serious accidents. Established safety methods should be applied to
the shipping and storage phases of this process.
4.8.3 Economic Factors
Franklin Research Center engineers determined a preliminary cost eva-
luation for the commercial destruction of PCBs by the sodium-polyethylene
glycol process (Pytlewski et al.,1980). Assumptions made were the follow-
ing:
» Construction of a complete disposal facility
9 Na metal currently selling for 90(t/kg
Polyethylene glycol 400 selling for 84
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a valuable source of energy. As stated earlier, it is also possible that
the recycled hydrogen gas could be used as a source of energy to melt the
Mad, though the cost of this method will need to be determined. Because
of a technical information gap, the overall energy effectiveness of this
process cannot be determined at this time, and an intensive energy study
will need to be carried out to determine all possible energy credits and
debits.
4.9 THE SUNOHIO PROCESS
4.9.1 Technical Factors
Limited data are available at this time pertaining to the fully opera-
tional mobile unit. A demonstration was performed on October 23 for the
EPA. Results and detailed process parameters do not exist in the litera-
ture currently. The following treatment is based upon generalized, non-
confidential information received from Sunohio. (Sunohio, 1980).
4.9.1.1 State of Technology-
It is stated that an operational mobile unit now exists which can
destroy PCBs in transformer oil after pretreatment consisting of filtra-
tion and removal of acids and other contaminants. The mobile unit will
remove and destroy all PCBs contained in the transformer oil and will leave
the oil in reusable condition. The process is also capable of destroying
pure PCBs.
4.9.1.2 System Design--
All the necessary process equipment is contained in a large mobile
tractor-trailer. The equipment is self-contained and can either generate
its own power or operate from an external electrical power source. Precise
system design parameters are not available from Sunohio at this time. A
detailed evaluation of the overall system design must include an analysis
of the various unit processes. A possible evaluation scheme could be or-
ganized as follows:
o Evaluation of the feed and pretreatment system, including
such processes as washing, filtration, and conventional
oil treating methods
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Evaluation of the reaction and processing scheme including
reactor design parameters
Evaluation of pollution control and effluent handling
systems. Product evaluation and process control methods
should be included.
Evaluation of all auxiliary equipment such as heat exchangers,
compressors, pumps, etc.
The transformer oil should be traced through the system, and all relevant
design parameters should be compiled and assessed.
4.9.1.2.1 Pretreatment and feedThe pretreatment process will consist of
filtering the heat transfer oil and removing moisture, acids, and other
contaminants from it. Other conventional oil treatment processes may be
needed for pretreatment. Feed composition should be monitored, and feed
rates need to be controlled. Injection devices, pumps, and heaters should
be adequately controlled to maintain constant flow rates and temperature
for the incoming streams. A gas chromatograph or any other suitable detec-
tion device should be used to analyze the incoming feed stream. The pre-
treatment evaluation should include an analysis of the vacuum degasser,
which is used to elevate the temperature of the oil before starting the
PCBX process.
4.9.1.2.2 ProcessingThe mobile processing unit is designed to process
3
about 1.9 m per hour of transformer oils containing up to 1000 ppm of PCBs.
Processing equipment which could affect operating variables include:
positive displacement pumps, automatically controlled heaters, reagent in-
jection devices, PCB injection devices (for pure PCB destruction), mixing
chambers, reaction vessels, heat exchangers, filter beds, and a vacuum de-
gasser.
Reaction temperature must be regulated closely because any flow-through
heaters or heat exchangers will directly affect the efficiency of the pro-
cess. Proper mixing is also critical. The transformer oil and the reagent
must be thoroughly mixed before entering the reaction vessel. Residence
time in the reactor is critical to the process. Heat must be removed from
the product effluent after leaving the reactor. Heat exchange between the
oil that will enter the vacuum degasser and the product effluent must be
carried out to cool the products to room temperature. The product stream
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will again need to be heated before entering the vacuum degasser. After
vacuum degassing, the decontaminated oil can be returned to the transformer
or kept in a retention tank.
The above processing steps should be evaluated according to how each
will effect the overall process efficiency. Important process variables
include the following:
Reaction temperature: the temperature should be well
below the flash point of the transformer fluid.
a Reaction times: the reaction times should be short
for this process. Holding times of only a few minutes
have been reported.
Stoichiometry: Theoretical limitations exist for the
minimum amount of reagent for any chemical reaction.
To meet process objectives, the proper reagent amounts
should be determined.
An assessment of optimum process conditions will need to be made. Lack
of data prohibits the assessment at this time.
4.9.1.2.3 Pollution controlThe overall pollution control equipment neces-
sary for this process appears to be minimal. The overall process depends on
the use of a reagent that strips the chlorine atoms from the biphenyl nucle-
us and generates naturally occurring chlorine compounds along with polymeric
biphenyl residues. Control of the naturally occurring chlorine compounds
can be accomplished using conventional methods. The polymeric biphenyl com-
pounds could be stored for possible reuse. Conventional methods also exist
for controlling these types of polymeric materials. The reagent used in the
PBCX process is not public knowledge at this time. An overall evaluation of
the necessary types of pollution control equipment must be done once detail-
ed process information becomes available. The possibility of other toxic
compounds being formed such as HC1 or halogenated aromatic compounds will
enter into the formal evaluation of the overall pollution control scheme.
The generalized process description appears to indicate that selective fil-
trations and conventional oil treatment should be able to remove trace quan-
tities of contaminants such as acids and toxic metals that could cause en-
vironmental damage. A pollution control evaluation should include how these
contaminants will be disposed of.
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4.9.1.2.4 Destruction efficiencyThe original goal in process development
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 have contained 0 ppm and 40
ppm respectively, after reaction under optimum process conditions. The
destruction efficiency for PCBs may be of the order of 99.6% more concentra-
ted fluids.
4.9.1.3 Process Controls--
Possible process equipment which would need to be controlled are:
positive displacement pumps, heaters, injection devices for reagents and
PCB oils, the mixing chamber, heat exchangers, filters and the vacuum
degassers.
Temperature and pressure must also be controlled in the reactor.
Pressure and flow regulators must be used to control pressures and flow
rates of all incoming and outgoing streams. Metering and mixing the re-
agent into the reactor must be controlled precisely. Obtaining the right
residence time in the reactor is also critical for achieving good reaction
results. Pollution control equipment should also be controlled automati-
cally to insure against malfunctions and possible waste discharge to the
environment.
4.9.1.4 Effluent Monitoring--
Because limited information exists about the composition of the efflu-
ent streams, it is difficult to speculate on the types of effluent monitor-
ing needed in this process. The mobile processing unit should contain ade-
quate effluent monitoring devices so the composition of each stream can be
calculated. It is extremely important thai the transformer oil and the re-
agent be well mixed before entering the reactor. This stream should be
monitored to insure adequate mixing. All streams entering and leaving the
vacuum degasser should be monitored to guard against the possibility of con-
taminated material being sent to storage or back to the transformer. Efflu-
ent monitoring must also be able to detect toxic compounds including PCBs,
HC1, and other chlorinated hydrocarbons in all waste streams. At this time
it appears that selective filtrations and conventional oil treatment should
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be able to remove trace quantities of acids and toxic metals. An overall
assessment of effluent monitoring must include the pretreatment system as
well as any auxiliary treatment processes. Adequate effluent monitoring
equipment and strategy will depend directly on the nature of the effluent.
Any solid waste effluents should be sampled by a grab technique. These
streams should be analyzed carefully for PCBs and other toxic compounds.
The plant should be equipped with automatic samplers on important effluent
streams to insure that representative cross sections are removed.
4.9.1.5 Waste Characterization--
All samples were analyzed in the laboratory for total chlorine content.
PCB solutions used in the laboratory studies contained Aroclors 1252 and
1254. Test solutions ranged from about 100 to 10,000 ppm PCBs.
4.9.1.5.1 Range of PCB concentrationThe process appears to be highly
successful in treating fluids containing as little as 100 ppm PCBs and as
much as 10,000 ppm PCBs. As stated earlier complete destruction is
claimed for fluids containing 100 ppm PCBs and greater than 99.6% destruc-
tion efficiency is claimed for fluids containing 10,000 ppm PCBs.
4.9.1.5.2 Limitations on constituentsAny contaminants such as acids,
trace metals, and dissolved solids must be removed by pretreatment. Any
substances that could cause corrosion or fouling of process equipment should
also be eliminated. Moisture content of the oil should be very low, thus
water must also be removed prior to treatment.
4.9.2 Environmental Factors
An environmental assessment study has not been developed for the PCBX
process. The scale up study should include a preliminary environmental
evaluation of the overall disposal operation as well as a detailed analysis
of all possible reaction products. Each generic effluent stream should be
analyzed for composition, and percent solids.
4.9.2.1 Potential Impacts of Disposal Operation--
Overall, the potential environmental impact of this disposal operation
appears to be very low. Either very little or no toxic products will be
produced. It is not known at this time whether there is a possibility of
1C7
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PCB release to ambient air. If such a release does occur, it would likely
be small. Analysis of all generic effluent streams should be an integral
part of the overall disposal operation evaluation. Since the transformer
oil is stripped of its PCB content and the chlorines are converted into
natural occurring chloride substances, environmental damage should be mini-
mal. The process unit appears to be equipped with special filtering de-
vices as well as conventional reclamation equipment to remove the excess
reagent and reaction products. In turn, the reclaimed and decontaminated
insulating fluid may be sent back to the transformer for direct reuse.
These two operations will lower the risk of environmental damage appreci-
ably.
4.9.2.2 Impacts of Disposal or Process Wastes--
All the products generated by the PCBX process appear to be environ-
mentally safe. The chemical reactions involved in the process convert
chlorine contained in the PCBs to naturally occurring chlorides. The ben-
zene nuclei are converted to polymeric solids which are insoluble in water,
oil, and all other common solvents. It has been shown in laboratory stu-
dies that there is only one chlorine atom contained in a total of 38 to 62
benzene rings in these solids. It was further determined that the biphenyl
polymer is 99% free of chlorine atoms. As stated above, the chloride pro-
ducts produced are claimed to be naturally occurring and non-toxic. The
polymeric solids could be reclaimed for use as polymers, and the transformer
oil is either stored for future reuse or sent directly back to the trans-
former. Based on the limited information available at this time, the envir-
onmental impact from process waste disposal appears to be minimal.
4.9.2.3 Potential Impacts of Accidents-
Spills or releases of PCBs from the PCBX process would appear to be
the most likely sources of accidents. The PCBX process units should be
evaluated as to how well accidental spills or releases could be prevented
or contained. The possibility of toxic materials being discharged must be
evaluated pursuant to EPA regulations. Construction of each mobile unit
must be in accordance with EPA standards for hazardous waste disposal faci-
lities. PCB storage and containment facilities should be evaluated with
respect to PCB Regulations (40 CFR 761.42). If adequate facilities are not
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available it is recommended that the facility not be approved. A spill or
release of PCBs from a PC3X processing unit could pose the following threats:
Contamination of surface or groundwater
Contamination of land areas where humans, animals, or
croplands are exposed
Contamination of areas that could lead to significant
airborne movement of PCBs
Accidents caused by possible malfunctions of processing equipment could also
occur. An assessment of these types of accidents should be carried out.
Operator safety should be considered when evaluating process equipment effi-
ciency. A detailed accident impact report should be developed for the PCBX
process before implementation of the scaled up mobile unit.
4.9.3 Economic Factors
A cost analysis of Sunohio's PCBX process is not available at this time.
It appears that a major capital investment is not required since the whole
system is completely portable. According to Sunohio, the overall economics
look favorable. Transformer oil can be decontaminated for $0.26-$0.77 per
liter. The theoretical reagent cost is $1.1 per kg.
Cost credit may be earned by reusing the decontaminated heat transfer
oil instead of discarding it.
4.9.4 Energy Factors
The amount of energy required per unit weight of PCB destroyed should
be determined for this process. The energy requirement does not appear to
be excessive at this time, although lack of data prohibits a quantitative
analysis. An efficient series of heat exchangers used to heat and cool the
treated oil should be able to reduce overall energy consumption appreciably.
Some of the heat content of the PCB waste should be able to be recovered to
produce steam. This will reduce the cost of energy by providing an energy
credit.
4.10 WET AIR OXIDATION
4.10.1 Technical Factors
The catalyzed wet air oxidation process developed by IT Enviroscience,
Inc. uses unique catalyst systems to accomplish a high level of PCB
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destruction at lower temperatures and pressures than conventional uncata-
lyzed wet oxidation processes. Because this technology is new, evaluation
of the various technical factors involved is very difficult. Detailed
evaluation should be carried out once scale up is completed.
4.10.1.1 State of Technology
This technology is new and not completely developed. IT Enviroscience
has recently completed feasibility testing and process development studies
for the destruction of PCBs. Data from these studies are not available at
this time, thus only a speculative assay of the technological impact can be
undertaken now. Engineering development of the process will be required
to define optimum operating conditions. A pilot plant is currently being
constructed for development of a continuous process for destruction of PCBs.
Scale up of a batch laboratory process for destruction of PCBs is also plan-
ned. Over 300 runs have been made in the IT Enviroscience laboratory-scale
titanium stirred reactor to examine the destruction properties of a wide
variety of hazardous wastes.
4.10.1.2 System Design--
IT Enviroscience system design objectives for the catalyzed wet oxida-
tion of PCBs included the following:
To achieve total destruction of PCBs and to minimize
by products requiring disposal
To reduce the amount of energy required for PCB disposal
t To have low reagent consumption
0 To have few unit operations
0 To create a low volume of effluents so that total containment
and pollution control processes will be simplified
0 To make the transition from laboratory to pilot plant fairly
simple
0 To be able to transport the process to facilities where the
PCB waste problem exists
Only a general description of this process is available at this time,
so that the treatment of system design parameters can only be taken as assump-
tions.
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4.10.1.2.1 Pretreatment and feedThe ITE process has so far been applied to
organic liquid residues and certain sludges and solid residues. Substances
such as metals or dissolved solids should be eliminated by pretreatment.
Substances that could cause corrosion or fouling in process equipment should
also be eliminated prior to the reaction. Conventional pretreatment methods
as well as any other suitable technique should be used for treating the
possibly- contaminated PCB fluid. Elimination of contaminants before pro-
cessing is an effective way of lowering possible emissions and will make
the process more efficient. The maximum PCB fluid input rate should be
determined accurately. Because this input rate is critical, the feed sys-
tem should be evaluated carefully. There may have to be an automatic flow
cutoff that will be activated if the desired feed rate is exceeded or if
other important process variables go out of tolerance. Overall, the pre-
treatment and feed system should be evaluated according to what types of
materials will be handled or treated.
4.10.1.2.2 ProcessingOptimum operating conditions will need to be deter-
mined for the scaled up version of this process. Under continuous feed
conditions, the PCBs must be added to the reactor at this steady state de-
struction rate. When the catalyst solution needs to be disposed of, the
reactor will need to be batch operated. It is important to note that PCB
concentrations are reduced to ppm or ppb levels at this time. This switch-
over from continuous to batch operation should be analyzed closely in a
pilot plant study. Heat and pressure are not used to drive the dissolution
of oxygen from air in the process. Instead, the catalyst is used to pro-
mote the oxygen transfer. Operating conditions must be able to be adjusted
to control the transfer of oxygen to the dissolved state by using gas and
liquid phase reactions accompanying the catalyst reaction with the PCB mater-
ial in the reactor. The overall conversion process should be evaluated
around the unique features of these catalyst systems. The most important
features in the processing step are that the nonvolatile organic material
remains in the reactor until destroyed and that there is no aqueous bottoms
product.
If batch processing of PCBs is to occur, the reactor must be sealed
and heated. The reaction will proceed for 2 hours at 573°K and 7 MPa. The
reactor must be cooled and vented. It is important to note that no vent gas
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is produced while the PCBs are being destroyed. The HC1 produced by the
oxidation must be distilled out of the reactor. The overall processing
steps should be evaluated on the basis of overall destruction efficiencies
achieved and the methods used to contain toxic or harmful effluents from
each unit process.
4.10.1.2.3 Pollution controlThe IT Enviroscience catalyzed wet air oxi-
dation process utilizes an efficient system for controlling waste products.
The only substances that leave the reactor are CCL, Np, water vapor, vola-
tile organics, and any inorganic solids formed. .Water and condensible or-
ganics are returned to the reactor. Any inorganic salts or acids formed
can be removed by treatment in a closed loop stream of catalyst solution.
Vent gases are low in volume and could be treated by conventional techno-
logies, such as absorption, adsorption, or scrubbing. Because the non-
volatile organics remain in the reactor until destroyed and since there are
no aqueous bottoms, pollution control should not pose any serious problems.
Conventional pollution control technologies should be able to handle waste
disposal problems readily. All generic effluent streams should be analyzed
and monitored periodically for waste content. The overall pollution control
system will need to be analyzed carefully upon scale up in accordance with
EPA regulations.
4.10.1.2.4 Destruction efficiencyOver 50 runs were made on PCBs by ITE
in a one liter titanium stirred reactor to define process conditions in the
laboratory. Greater than 90% destruction of PCBs have been repeated, accom-
plished by oxidation at 523°K for two hours. It is important to note that
it is not necessary to achieve 99+% destruction of the PCB since the amount
of PCBs that is not destroyed will remain in the reactor until it reacts
and undergoes destruction.
4.10.1.3 Process Controls
The following unit operations will need to be controlled either auto-
matically or manually:
Pretreatment and feed
Addition and removal of reactants and products to the reactor
o The chemical reaction itself
Treatment of product waste streams
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An assessment of the types of controllers will need to be carried out.
Under continuous feed conditions, PCBs must be added to the reactor
at their steady state destruction rate. Flow controllers will be needed
to regulate this. Flow rates of all streams entering and leaving important
process equipment should be controlled to insure smooth operation. Flow
rates must also be controlled to achieve the optimum operating conditions.
Temperature control may also be critical to the system. Temperature
will effect reaction rates and overall destruction efficiency. The process
should contain adequate temperature monitoring and control devices located
at appropriate stations throughout the system. The temperature in the re-
actor must remain within the defined operating range for high destruction
efficiencies. Temperature must be controlled in any heat exchangers, con-
densers, columns and any other heat sensitive processing equipment.
Pressure control will be needed to insure against excessive pressure
drops in heat exchangers, pumps, compressors, etc. Pressure may also need
to be controlled in the reactor, and any columns such as absorbers, scrubbers,
etc.
All storage and processing tanks should be filled to appropriate levels
to insure smooth and steady flow throughout the process. Level controllers
should be installed in these tanks.
An overall assessment of the types of controllers needed to completely
regulate this process should be done as part of the pilot plant study.
4.10.1.4 Effluent Monitoring
As stated earlier, the substances that leave the reactor in the ITE
catalyzed wet air oxidation process are CO^j Npj water vapor, volatile or-
ganics, and any inorganic solids formed. Condensible organics will be re-
turned to the reactor. Effluent monitoring should center around the streams
in which these components are contained.
Overall, the vent gases are low in volume but should be monitored,as
they may contain various volatile organic substances. In evaluating the
effluent monitoring system, the Regional Administrator should assess the
capability of the facility operator to monitor all process effluent streams
that could contain toxic levels of waste material. Ambient air samplers
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placed at specific locations around the reprocessing plant should be capable
of detecting dilute concentrations of PCBs and other toxic compounds. Per-
iodic air samples should be collected and analyzed for PCB content and total
composition. In addition, post operational air samples should be collected
and analyzed.
Liquid effluents should be monitored for flow rates, temperatures,
pressures and composition. Each of these variables could critically affect
overall process effectiveness. Each effluent stream could be monitored
with conventional monitoring devices such as chromatographs and spectromet-
ers. If a scrubber or absorption unit is used to remove chlorinated by
products effluent streams from these units must be monitored and sampled
on site. No limit on the PCB content of scrubber effluent streams is given
except indirectly through reference to applicable effluent standards and
any other state or Federal laws and regulations. The effluent monitoring
capability of a facility should be determined by the facility operator's
description of the appropriate streams.
Since various types of inorganic solid wastes may be generated,they
should be sampled by a grab technique. Solids monitoring should bp evalu-
ated on the basis of amount and type of solid waste required and on the
adequacy of the solid sampling locations.
4.10.1.5 Waste Characterization
An accurate analysis of all effluent streams is needed to determine
the nature of all process wastes. Only after these wastes are determined
can effective disposal methods be applied. Scale up studies should include
possible alternative procedures for handling the various process wastes.
4.10.1.5.1 Range of PCB concentrationThe laboratory studies used five to
six grams of Askarel (56% PCBs and 44% trichlorobenzene) to determine de-
struction efficiencies. This process may be adaptable over a wide range
of PCB concentration. Transformer oils with >500 ppm PCBs might possibly
be disposed of in this process.
4.10.1.5.2 Limitations on constituentsAny inorganic salts, acids, trace
metals,and any substances that could cause fouling or corrosion of process
equipment should be eliminated by pretreatment. Moisture should be
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eliminated before processing, and traditional oil cleaning methods should
be used to eliminate trace impurities from the PCB oil. An extensive study
should be carried out to determine the effect of the possible contaminants
on the reaction and overall process variables. Any substance that can be
oxidized or can react with the catalyst could interfere with the PCB oxi-
dation. These substances should be determined and removed before process-
ing the PCB oil.
4.10.2 Environmental Factors
It is extremely difficult to estimate environmental impacts of the ITE
catalyzed wet air oxidation process at this time. Currently, data are not
available so an environmental assessment will need to be done during a
scale up study. The following impact analysis must be taken as speculative
in nature.
4.10.2.1 Potential Impacts of Disposal Operation--
Minimal environmental impacts would be expected from the catalyzed wet
air process operations during PCB disposal since the PCBs remain in the re-
actor until destroyed and there is no aqueous bottoms product. As stated
earlier, CO-, N2» water vapor, volatile organics and inorganic solids leave
the reactor. The water and condensable organics are returned to the reac-
tor for further degradation. This step reduces the volume of toxic organic
substances that could be contained in the effluent streams. The inorganic
salts could easily be removed using conventional methods so environmental
impact from them would be minimal. The vent gases are low in volume and
could be treated by conventional techniques. Further research will need
to be done to develop a detailed environmental assessment of this process.
4.10.2.2 Potential Impacts of Disposal of Process Wastes--
Analysis of all generic effluent streams will need to be carried out
in order to evaluate the potential impacts of waste disposal.
Vent gases will be small in volume but may contain HC1 and other
toxic substances. Various types of chlorinated hydrocarbons could possibly
be contained in the vent gases. Particulates could also escape with the
vent gases. All of these substances can be safely removed by conventional
methods so pose no real threat to the environment. If a scrubber or
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absorption column is used to remove contaminants, the effluent leaving the
units must be monitored. No PCBs have been formed in the vent gas from
the reactor, so possible environmental impact is minimal. The vent gas
from the reactor and the vent gas from a scrubber are low and readily
adaptable to polishing treatment for control of trace toxic compound re-
leases.
4.10.2.3 Potential Impacts of Accidents--
PCB entry into the environment by vaporization into the atmosphere
(and by subsequent deposition into land and water) and by spilling or dump-
ing into water or onto land are the two major impacts of this process.
The possibility of accidental release to the atmosphere from spills and
leaks will continue to pose a threat as long as PCBs exist, but by using
available control technology, it is possible to minimize PCB loss during
transfer, storage, and disposal operations.
A spill or release of PCBs from a catalyzed wet air oxidation process
facility could pose the following threats:
Contamination of surface or groundwater
Contamination of land areas where humans, animals,
or croplands could be exposed
Contamination of areas that could lead to significant
airborne movement of PCBs.
Because of the limited amount of information available and because of
the direct threat to the environment of potential PCB spills,the catalyzed
wet air oxidation facility should be evaluated very carefully with respect
to PCB storage and containment. An overall assessment of the potential im-
pacts of accidents in all the units of the process will need to be carried
out upon commercialization of this technology.
4.10.3 Economic Factors
Economic data for the IT Enviroscience catalyzed wet oxidation process
for the destruction of PCBs are not available at this time. Information
that should be evaluated include:
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« Capital costs -- What will be the cost of the facility?
Operating costs -- What will it cost to dispose of the PCB
waste, per pound of waste, or per pound of PCB? What will
be the cost of reagents, utilities, etc., and how do these
costs vary with PCB content?
t Disposal costs What are the costs of disposing of
wastewater and solid waste?
t Credits for products or by products -- Are soluble materials
produced?
i Financial requirements -- What are the expected costs of
closure and post closure monitoring and maintenance, and
how will these costs be paid?
Regulatory costs -- Will the regulatory process result in
an increase in costs?
A cost analysis and feasibility study is currently being carried out
by IT Enviroscience to determine the economic viability of this process.
Qualitatively this process seems to be economically feasible. Little
or no added energy is required and no auxiliary fuel is consumed. Chemical
consumption is small in this process, lowering the cost appreciably.
4.10.4 Energy Factors
IT Enviroscience cannot supply energy consumption data at this time.
The amount of energy consumed per unit quantity of PCB waste should be com-
pared to the similar figure for an Annex I incinerator. The energy utili-
zation system should also be evaluated for possible energy credits such as
the possibility of recovering any waste heat for use in steam generation
or for the reclamation of materials which could be used as fuel.
According to IT Environscience, little or no added energy is required
and no auxiliary fuel is consumed. The heat of reaction provides ample
heat to drive the reaction of the catalyst, PCB liquid, and oxygen,
Qualitatively, it appears that this process does not use an excessive a-
mount of energy, although a thorough heat balance will need to be performed
around each unit process to determine the overall heat demand.
117
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5. EVALUATION OF BIOLOGICAL PROCESSES
As noted in Section 3.2, 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 microorganisms with the fluid containing the
species to be degraded, means of providing oxygen (air or 02) to the micro-
organisms, and in pre- and post-treatment steps.
The literature review indicated that most commercial aoplications of
biological processes are to aqueous streams containing relatively small
amounts of organic compounds. Laboratory studies have shown that pure Aro-
clor mixtures are degraded and that degradation rates are inversely related
to increasing chlorine substitution. U.S. Air Force studies (U.S. Air Force,
1974) showed that some microorganisms degraded the very concentrated Herbicide
Orange components over a period of years. Commercial land farming is used
to degrade oil-contaminated industrial aqueous wastes. However, PCBs are
more refractory than the major Herbicide Orange components and oils. No
studies on purely non-aqueous PCB-containing materials were found.
5.1 ACTIVATED SLUDGE METHODS
5.1.1 Technical Factors
5.1.1.1 State of Technology--
Activated sludge methods are well developed and widely used at commercial
scale for treatment of sewage and industrial wastewaters. As a well developed
technology, most aspects of an activated sludge treatment facility need only
be evaluated cursorily.
The literature search did not locate any work describing deliberate PCB
disposal by activated sludge methods at the commercial scale. A laboratory
scale study (Tucker, et al., 1975) showed percentage degradations of Aroclors
fed at 1 mg/48 hr ranging from 81 percent for Aroclor 1221 to 15 percent for
Aroclor 1254. Tri-, tetra-, and pentachloro isomers were undergraded. The
finding of PCBs (mono-through decachloro isomers) in samples of municipal
118
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sewage sludge indicates that some plants cannot handle PCB degradation
(Erickson and Pellizzari, 1979). No references to commercial or lab scale
applications to non-aqueous streams were found.
It is concluded that activated sludge methods cannot be considered
technically applicable at this time to general disposal of PCBs and PCB
Items. While trace quantities of PCBs could be fed into a commercial scale
process and while some degradation will occur, destruction will not be
complete, and the amounts fed will be so small as not to aporeciably aid the
PCB disposal problem.
Further research is warranted, but the research might most profitably
be pursued in the following areas: 1) more effective treatment of sewage
and wastewater already contaminated by PCBs, 2) treatment of PCB-contaniinated
dredge spoil, and 3) developing microorganisms effective at degrading PCBs.
5.1.1.2 System Design--
In general, an activated sludge sewage/wastewater treatment facility
consists of the following unit operations: 1) pretreatment and
feed, 2) primary clarifier with or without recycle of excess activated
sludge, 3) equalization basin, 4) aeration basin(s), 5) secondary clari-
fier(s), 6) dewatering, 7) drying, and 8) final disposal. Because applica-
tions of activated sludge treatment are well developed1 for sewage and waste-
water, only those aspects of system design that affect PCB disposal need be
considered. It should be noted again that activated sludge methods are
biological processes and, hence, have limited ability to handle high con-
centrations of toxic compounds, such as PCBs.
5.1.1.2.1 Pretreatment and feedTypes of pretreatment that may be necessary
include: 1) maintenance of an appropriate PCB input rate, 2) nutrient addi-
tion, 3) pH adjustment, 4) dilution, 5) extended acclimation, or 6) removal
of toxic elements (e.g., precipitation of heavy metals).
Activated sludge treatment is a lengthy process. Thus, there must be
foreknowledge of the adequacy of destruction efficiencies. Given this know-
ledge, the maximum PCB input rate can be predetermined. Because the PCB
input rate is a critical value, the feed system will have to be evaluated
carefully. There must be an automatic cutoff that will function if the
119
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desired feed rate is exceeded and if other important process variables go
out of tolerance.
Nutrient addition for PCB disposal may or may not be necessary. Infor-
mation supplied by the facility operator should identify whether nutrient
addition is necessary. The same consideration applies to pH adjustment and
removal of toxic elements.
Dilution may or may not be necessary. For example, if the source of
PCBs to the treatment plant is PCB-contaminated dredge spoil, then dilution
may be necessary to keep solids fed to the process basins about 20 percent
Similarly, a concentrated PCB feed will need to be diluted or fed at a rate
sufficiently slow in order to preclude toxic effects to the microorganisms.
Acclimation may be necessary to allow the microorganisms to adjust to
PCBs being fed to the process. Thus, the initial PCB feed rate may have to
be much lower than that ultimately achievable in order to build up a suitable
population of microorganisms.
5.1.1.2.2 ProcessingUnit processes of principal interest to PCB disposal
and those requiring evaluation are primary clarification, equalization basins,
and aeration basins. PCBs tend strongly to adsorb on inorganic oarticulate
matter (e.g., soil particles). Thus, the clarification stage must be eva-
luated to determine whether all settled particulate material is eventually
fed to the aerator basin(s). Because of the tendency of PCBs to adsorb on
particles, the material from the clarifier should not be discarded without
either being analyzed for PCBs or being processed through the aeration basin.
The equalization process should be evaluated with resoect to PCB vapor
emissions and the fate of any settled particles. Although the amount of
PCBs fed into the system should be small, low molecular weight PCBs (e.g.,
monochloro isomers) may escape from solution. Also, any particles that
settle in the equalization basin should, unless analyzed for PCBs, eventually
be transferred to the aeration basin.
The aeration basin(s) is the heart of an activated sludge process, for
it is where the microbial degradation actually occurs. Process design con-
siderations for aeration basins include provision for adequate levels of
dissolved oxygen in the waste water, maintenance of a proper concentration
120
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ratio of active biomass to organics, and sufficient mixing and contact time.
Typical design parameters for aerobic digestion are (EPA, 1974):
o Solids retention: 15-20 days
0 Dissolved oxygen: 1-2 mg/1
Temperature: >288°K
Information supplied by the owner/operator of a facility proposing
disposal of PCBs should include enough process information so that the
Regional Administrator can compare the proposed process with otner similar
processes. Additionally, the information should clearly state any changes
in process parameters necessary for PCB disposal.
After digestion is complete, the sludge is conditioned to facilitate
dewatering and is then dewatered, dried, and disposed of.
5.1.1.2.3 Pollution control--Activated sludge wastewater treatment processes
produce three generic effluent streams: dried sludge, supernatant water,
and gas. The bulk of undestroyed PCBs would probably be found in the dried
sludge because PCBs tend to adsorb strongly on particles and because the
more highly chlorinated PCBs tend to be the isomers least degraded by micro-
organisms. PCBs adsorbed in the sludge should be relatively resistant to
being leached. Dried sludge from such a treatment process should be care-
fully investigated for residual PCBs in order that the appropriate means of
disposal can be used.
The supernatant liquid from an activated sludge treatment process should
also be carefully analyzed despite the fact that the bulk of undegraded PCBs
should be adsorbed in the sludge. Sampling and analysis is particularly
necessary if the activated sludge process is the last stage (i.e., secondary
treatment only) and the supernatant will be discharged directly into the
environment (e.g., river, lake, sea).
Aerobic activated sludge wastewater treatment processes typically do not
generate significant odors. Water and CC^ are the primary products of
microbial digestion of organic matter fed into the system. If the degrada-
tion process stops at monochlorobiphenyls, then traces of these may escape
in the vapor phase. Research should indicate whether this may occur. If
significant amounts of low molecular weight PCBs can escaoe as vapor, then
121
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there are several options:
Seal those unit processes that can emit PCBs and treat the
emitted gases (adsorbers, incinerator, or partial recycle
through the digester)
o Reduce PCB feed rate so that emissions are acceptable
5.1.1.2.4 Destruction efficiencyIn a pilot scale study, Tucker, et al.
(1975) showed destruction efficiencies (percentage degradations) ranging
from 81 percent for Aroclor 1221 to 15 percent for Aroclor 1254. Destruction
efficiencies of current processes decrease rapidly with increasing chlorine
substitution. It is doubtful whether any activated sludge process will be
capable of destruction efficiencies equivalent to those of high efficiency
boilers or Annex I incinerators.
5.1.1.3 Effluent Monitoring
As noted above, biological treatment methods, such as activated sludge,
are not likely to achieve high levels of destruction efficiency. Thus, if
such a method is used for PCB disposal, careful effluent monitoring is
necessary to determine the extent of degradation and assess the potential
environmental impacts of undestroyed PCBs.
Conventional activated sludge wastewater treatment plants are usually
well equipped with test ports for liquid and sludge sampling because extensive
routine monitoring for water and sludge quality parameters is performed.
In a "Trial Burn" situation, daily composite water and sludge samples should
be taken in order to determine the rate of PCB degradation. Because aerobic
activated sludge treatment plants are typically not enclosed, gaseous emis-
sions of PCBs probably would best be sampled by means of high volume ambient
air samplers modified with polyurethane foam as an adsorbent (Stratton, et
al., 1978). Several such samplers should be used with at least one upwind
of the source of PCB emissions.
5.1.1.4 Waste Characterization
5.1.1.4.1 Form of wasteActivated sludge treatment processes seem best
suited to handle aqueous streams or dredge spoil contaminated with
PCBs. If PCB Items are to be treated, they should be finely shredded.
5.1.1.4.2 Range of concentrationsAs noted earlier, biological processes
122
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are not well suited to high concentrations of toxic organic compounds. With
extended acclimation, higher levels of such compounds may be tolerated. No
information on tolerable levels of PCBs was found. Given that EPA's fresh
water criterion for PCBs of 1.5 ppb is intended to provide adequate protec-
tion for freshwater life (EPA, 1978), it seems unlikely that PCB concentra-
tions more about 3-4 orders of magnitude greater v/ould be tolerated.
5.1.1.4.3 Limitations on constituents--PCB wastes containing excessive con-
centrations of toxic heavy metals will require pretreatment prior to entering
the aeration basins. The extent and type of treatment will depend on the
process and experience of the owner/operator.
5.1.2 Environmental Factors
Because no references on disposal of PCBs by activated sludge treatment
were found, it is difficult to estimate environmental impacts of such a
disposal operation.
5.1.2.1 Potential Impacts of Disposal Operation--
Minimal environmental impacts would be expected from activated sludge
process operations during PCB disposal because of the expected small amounts
of PCBs involved and because such processes routinely operate without adverse
impact. There is a possibility of PCB release to ambient air, but releases
should be small. Testing, however, is needed.
5.1.2.2 Potential Impacts of Disposal of Process Wastes--
As discussed earlier, activated sludge treatment processes generate
three types of generic effluent streams: sludge, supernatant water, and
vapors. The bulk of residual PCBs would be expected in the sludge. The PCB
content of the sludge will be affected by several later process steps:
drying (multiple hearth, flash dryers, tray dryers, spray dryers) and final
reduction to reduce volatile organics (incineration, wet air oxidation,
pyrolysis). Final disposal methods for solids from activated sludge pro-
cesses include cropland application, land reclamation, power generation
(co-fired with other fuels), sanitary landfill, and ocean dumping (EPA,
1974).
123
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The method of final sludge disposal is an important consideration
because it determines the form of the sludge residue and liquid unit pro-
cesses to be employed. The method of final sludge disposal is also an
important consideration in selecting a plant for PCB disposal. If the drying
and final reduction stages of sludge treatment leave PCB residues, then
certain final disposal options, such as cropland application, land reclama-
tion, or ocean dumping, may pose undesirable environmental impacts.
The supernatant water, after completion of the activated sludge treat-
ment., is not expected to contain appreciable amounts of PCBs although addi-
tional research is necessary. However, subsequent use of the supernatant
water is an important consideration. Activated sludge treatment is a secon-
dary treatment, and the supernatant water is not of drinking water quality.
Tertiary treatment of the supernatant water can upgrade it to drinking water
standards. Generally, however, supernatant water from activated sludge treat-
ment is dumped into rivers, lakes, or oceans. Unless testing determines that
the PCB content of supernatant water is at or below applicable standards,
then direct discharge of the supernatant could cause undesirable environ-
mental impacts. It would probably be undesirable with respect to public
concern to discharge the supernatant water into a tertiary treatment stage
if the treated water is used directly for drinking water.
5.1.2.3 Potential Impacts of Accidents--
A spill or release of PCBs from an activated sludge treatment facility
may pose the following threats:
Contamination of surface or groundwater
Contamination of land areas where humans, animals, or
croplands could be exposed
Contamination of areas that could lead to significant
airborne movement of PCBs
A spill into the process itself poses potentially more significant threats
and is cause for very careful control of PCBs fed into the process. These
threats are:
Creation of a large volume of contaminated v/ater and
sludge
Contamination of surface or groundwater if supernatant
water is directly discharged into the environment
124
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a Contamination of surface water or drinking water if
the supernatant is discharged into a tertiary treatment
section
As noted in Section 2.1, regulations pursuant to the Clean Water Act
currently reciuire, and to RCRA will require, facilities disposing of PCBs
to prepare spill prevention, control, and countermeasures plans. These
plans are intended to detail safe handling procedures of hazardous materials
(i.e., PCBs), but they also must address prevention and control procedures
when a release of PCBs occurs. The goals are to prevent discharges and to
minimize impacts of spills. An adequate SPCC plan should minimize the
potential for spills and, hence, potential environmental impacts from spills.
An activated sludge treatment plant is not typically in the hazardous
waste disposal business. Thus, it is not expected that such a plant will be
constructed in accordance with RCRA standards for hazardous waste disposal
facilities. Because of the very direct threat to the environment of poten-
tial PCB spills, an activated sludge treatment facility should be evaluated
very carefully, especially with respect to PCB storage and containment. If
adequate storage (mandated by the PCB Regulations, 40 CFR 761.42) and adequate
containment facilities are not available, it is recommended that the faci-
lity not be approved.
5.1.3 Economic Factors
The most expensive unit processes in a typical activated sludge waste-
water treatment facility are the sedimentation basin, sludge dewatering, and
chemical storage/feed facilities. The major operating and maintenance costs
would be for labor and chemicals. Tables 7 and 8 summarize important
capital and operating and maintenance costs for a 0.31 m /sec activated sludge
wastewater treatment facility located in Chicago, Illinois. The cost
estimates are based on mid-1978 dollar values.
It appears that an activated sludge treatment facility processing PCBs
should have costs similar to those presented in Tables 7 and 8, although a
detailed economic analysis would need to be done because of possible
regulatory and disposal cost requirements. Both capital and operating costs
appear to be moderate.
125
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IV)
cr>
TABLE 7. SUMMARY OF CAPITAL COSTS FOR ACTIVATED SLUDGE
(Hansen et al, 1978)
Cdpllul Coil
Cdluijury Module
bud IlllUlldll fill
lldiln
Aciiiluil bus m
Cldilfier
S ludijo iluwtiiuring
CliL'iniidl toed
Cliumlc.il feud
riiciiiltdl pump
LhriniCdl pump
UjStc pump
lldsle pump
Sludiju pump
Ydfd pipliuj
Inldl
bllpplL'llll.'llltll
Cdplldl CllbtS
buliloldl Of
Cdplldl CI)*itS
M.HMlKJ LdplUl"
Aim i
(ii.uij ioi.ii or
Ldplldl rOblS
SI ic
Priipardllnn
t 29.700
10.500
905
170
14.710
0,330
...
900
65.313
...
...
Struclutcs
$ 211 .000 I
lie .000
115.000
42 .600
213.000
107 .000
...
...
...
834 ,600 2
141.3031
...
---
(usUI
MuihdiilCdl
1 ""U"1
7b6 .000
17), mm
22 . 100
91'j.noo
93b .001)
2'J.bOO
1 ,5JO
1.4/0
10.1100
10.1100
4 .490
5b.20l)
.927.090
...
...
Electrical
t<|uipmrill Ldiid
( 2 .020 t 25 ,'jOO
12.1100
1/2 d15
9.I90 4.120
6.220
1.520
...
... ...
...
11.302 50.005
...
---
IT." III
Older
1 tiud
(Oldl (fl?)
3i.:ioo
17.200
m.7
5.b.lO
0.362
2.0J9
...
... ...
...
60.290
4.030.193 ---
9/.02I
201.525 ---
'
4,329,039 ---
5,000 fj|iiii; total nitrucjuii = 2.0 ppm; lotdl phosphorus = 1.0 ppm. 000 = 150
I Mid-1970 ilulldrs
I Uuilding
At (iiif mini Hi of direct operating costs
) Alldwdiice fur funds during construction at 5X of capital costs
eproduced from
g^s» available copy
-------
ro
TABLE 8. SUMMARY OF FIRST YEAR OPERATING AND MAINTENANCE COSTS
FOR ACTIVATED SLUDGE
(Hansen et al, 1978)
(1KM Cos I
Cdlt'ijiiiy
Minlnlc
j>,:d,,H,,,Ul,0«
Ariiilrd litisln
1 Idi 1 1 lor
bllllllJL'
ili-walut IIHJ
I Ill-Ill) L.I 1 IcUtl
III Kill ICL'rf
CIlL-IIIILdl |llllll|l
I lii-iiil i ill |IIIHI)I
W.islu |iinii|)
UdSlL* |llllll|)
blinliji: pump
Yillll (llpllKJ
li.l.il
Type; 1
Opei at or 1
117.77/lirjL
(3.911
3.521
10.636
2.93J
.-
..
..
--
--
--
--
21.001
Labor
lype 2
Ope M lor 2
(19 19/hr)
( 2/6 $
IIJ1
7!ib
900
--
_.
--
--
--
-.
.-
--
2.762
Type J
1 dunrtM'
Jl6.7fi/lir]
40.1150
33 .fillfi
111.0/11
30.617
...
17!)
216.430
C.»U I
liiL'iijy
t )c(.li ical
I ($0 OI'./KWII)
J 10? f
'1 , 7'JO
1(12
70 .'jlID
Jl
I/
II.OJII
U.6JI)
4 .4'JO
«J6 .2%
Mdl nit-nance
Los is
6H.600
34.100
2 .<> JO
9.240
UOO
1100
363
I16.2J3
CIlL'lllKdl
Costs
J ....
2 .020
699 .01)0
H./40
/09.760
Ollu-r
Total Kllll
(y)
2.UI4
103,2116
2. 911
2,OI4.2II!>
...
I .01)0
4116
246.ii/l
246.S./I
I2U.2II6
2.751. 313
OM-1
tiililotul i)t
IIIOI.L OHM costs --
Ailiiiiiiisliullvu
(IVOI Ill-illlif
Drill SL-IVICC Olid
dlhOI 11 2
232.11'jO
704.'j31
' 06 .Sill
2.108.214
-------
5.1.4 Energy Factors
Generally, energy consumption is low for activated sludge wastewater
treatment facilities. The amount of energy required per unit of PCB waste
processed would need to be determined in the overall economic analysis.
5.2 TRICKLING FILTER METHODS
5.2.1 Technical Factors
5.2.1.1 State of Technology-
Trickling filter methods are well developed and widely used for de-
gradation of dilute, non-biocidal, organic waste streams.
A literature search did not uncover any work describing PCB disposal
by trickling filter methods. Likewise, no references to commercial scale
applications to non-aqueous streams were found. It is concluded that
trickling filter methods cannot be considered technically feasible for the
disposal of PCBs and PCB items at this time.
5.2.1.2 System Design-
Basically, a trickling filter wastewater treatment facility is designed
to distribute a uniform amount of wastewater over the trickling filter
media by a flow distributor. A large amount of the wastewater applied to
the filter should pass through rapidly, and the remainder should slowly
trickle over the surface of the slime. BOD removal occurs by biosorption
and coagulation from the rapidly moving portion of the flow and by progres-
sive removal of soluble constituents from the more slowly moving portion of
the flow.
System design should be based on the following: 1) amount of available
food to control the quantity of biological slime produced, 2) hydraulic
dosage rate, 3) type of media, 4) type of organic matter, 5) amount of es-
sential nutrients present, 6) nature of the type of biological growth.
5.2.1.2.1 Pretreatment and feedTypes of pretreatment that may be neces-
sary include: 1) maintenance of an appropriate PCB feed rate, 2) nutrient
addition, 3) removal of toxic elements such as heavy metals and toxic
compounds, 4) dilution, and 5) pH.
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Since the PCB input rate is critical to the process, the feed system
will need to be evaluated critically. Automatic shutoff devices should be
installed that would be activated if the optimum PCB feed rate is exceeded
or if other important process variables deviate from their specified ranges.
Nutrient addition, pH adjustments and removal of toxic elements may
need to be carried out depending on the nature of the waste. Information
supplied by the facility operator should be adequate to determine if the
above operations need to be carried out.
Dilution may be necessary if the PCB waste fed into the facility is
too concentrated to be filtered effectively. Since the quantity of biolo-
gical slime produced is controlled by the available food, dilution may be
needed to adjust the PCB feed stream to acceptable levels.
5.2.1.2.2 ProcessingThe following factors could affect the performance
of this process if adapted to handle aqueous streams containing PCBs: 1)
wastewater characteristics, 2) trickling filter media, 3) trickling filter
depth, 4) recirculation, 5) hydraulic and organic loading, 6) ventilation,
and 7) temperature of applied wastewater.
The strength of wastewaters can vary greatly over a daily period. An
effective way of minimizing these variations is to recirculate filter ef-
fluent through the primary clarifier.
Various types of trickling filter media should be compared on the basis
of physical properties. Specific surface area and percent void space will
have a pronounced effect on PCB processing. Greater surface areas permit a
larger mass of biological slime per unit volume,while increased void space
allows for enhanced oxygen transfer and higher hydraulic loadings.
Trickling filter depth will directly affect the treatment efficiency
of the process and is a major design parameter. The treatment efficiency
of a synthetic media trickling filter is much more responsive to variations
in depth than a stone media trickling filter.
Recirculation of the effluent can be used to improve the efficiency
and operation of stone media trickling filters.
129
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Hydraulic loading rates directly affect the performance of a trickling
filter. Hydraulic loading will closely predict the performance of a stone
media trickling filter.
Proper ventilation of trickling filters is necessary to maintain aero-
bic conditions throughout the filter media. It should be determined whether
or not forced ventilation is necessary.
The efficiency of trickling filters is affected by temperature changes.
The effect of temperature on filter performance may show up when comparing
summer efficiencies with winter efficiencies.
Information supplied by the owner/operator of a facility proposing
disposal of PCBs should supply enough process information so that the
Regional Administrator can compare the proposed process with other similar
processes. The information should clearly state any changes in process
parameters necessary for PCB disposal.
5.2.1.2.3 Pollution control--Trick!ing filter wastewater treatment pro-
duces two generic effluent streams: dried sludge and final waste effluent.
Most of the undestroyed PCBs would probably be found in the dried sludge
since PCBs tend to adsorb strongly on particles and because highly chlori-
nated PCBs tend to be poorly degraded by microoganisms. The PCBs adsorbed
in the sludge should be relatively resistant to being leached. The dried
sludge should be carefully analyzed for residual PCBs, so that an appropriate
disposal method can be chosen.
The final waste effluent should also be carefully analyzed even though
most of the undegraded PCBs should be adsorbed in the sludge. Sampling
and analysis will be needed if the effluent is discharged directly into
the environment (e.g., rivers, lakes, seas, etc.).
Trickling filter wastewater treatment processes typically do not gen-
erate significant wastes. Water and C02 are the main products of microbial
digestion of organic matter fed into the system. Research will be necessary
to determine the amount of chlorinated biphenyls that may pass through the
filter and into the secondary clarifier. Conventional pollution control
devices should be adequate to prevent excessive PCB release from the sys-
tem.
130
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5.2.1.2.4 Destruction efficiencyAs stated earlier, an extensive litera-
ture search could not uncover any trickling filter processes applied to
PCB destruction. It can be expected that destruction efficiencies will
decrease with increasing chlorine substitution. At this time it appears
doubtful whether any activated sludge process will be capable of destruc-
tion efficiencies equivalent to those of high efficiency boilers or Annex
I incinerators.
5.2.1.3 Effluent Monitoring
As stated above, trickling filter treatment methods are not likely to
achieve high levels of destruction efficiency. If such a process is used
for PCB disposal, careful effluent monitoring will be needed to determine
the extent of PCB degradation and to assess the potential environmental
impacts of undestroyed PCBs.
Conventional trickling filter wastewater facilities are normally well
equipped with efficient effluent monitoring devices because extensive moni-
toring for water and sludge quality is necessary. Daily composite water
and sludge samples should be taken in order to determine PCB degradation
rates.
5.2.1.4 Waste Characterization
5.2.1.4.1 Form of wasteTrick!ing filter treatment processes are best
suited to handle aqueous streams contaminated with PCBs. If solids are to be
treated, they should be finely shredded.
5.2.1.4.2 Range of PCB concentrationAs stated earlier, trickling filter
processes are not well suited to high concentrations of toxic organic com-
pounds. No information on possible tolerable levels of PCBs could be found.
Given that EPA's fresh water criterion for PCBs of 1.5 ppb is intended to
provide adequate protection for fresh water life (EPA, 1978), it seems un-
likely that PCB concentrations of more than 3-4 orders of magnitude greater
could be tolerated.
5.2.1.4.3 Limitations on constituentsPCB wastes containing excessive con-
centrations of toxic materials such as heavy metals will require pretreat-
ment prior to entering the trickling filter. The type of pretreatment will
depend on the nature of the toxic substances.
131
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5.2.2 Environmental Factors
Because no references on disposal of PCBs by trickling filter treat-
ment were found, it is extremely difficult to estimate the environmental im-
pacts of this disposal process.
5.2.2.1 Potential Impacts of Disposal Operation--
Minimal environmental impacts would be expected from trickling filter
process operations during PCB disposal because the quantity of PCBs being
processed would be small. There could be slight releases of PCBs to am-
bient air so air sampling and testing is needed.
5.2.2.2 Potential Impacts of Disposal of Process Wastes--
As stated earlier, trickling filter treatment processes generate two
types of generic effluent streams: dried sludge and final effluent water.
Most of the residual PCBs would be expected to be found in the sludge. The
PCB content of the sludge could be affected by subsequent processing steps
such as drying. Final disposal methods for solids from trickling filter
processes include: land reclamation, cropland application, sanitary land-
fill, and ocean dumping (EPA, 1974).
Final sludge disposal methods must be chosen carefully since they will
determine possible environmental impacts. If the final drying and reduction
stages of the sludge treatment leave PCB residues, then certain final dis-
posal options such as cropland application or land reclamation may be unde-
sirable.
The final effluent water should not contain any appreciable amounts of
PCBs. Trickling filter treatment is a secondary treatment, and the effluent
water is not of drinking quality. Tertiary treatment should be able to up-
grade the effluent water to drinking quality. However, effluent water from
trickling filter treatment is usually dumped into rivers, lakes, or oceans.
Testing should be done to insure that the PCB content of the effluent water
meets applicable standards.
5.2.2.3 Potential Impacts of Accidents--
A spill or leak of PCBs from a trickling filter treatment facility
could pose the following threats:
132
-------
Contamination of surface groundwater
i Contamination of land areas where humans, animals, or
croplands could be exposed
Contamination of areas that could lead to significant airborne
movement of PCBs
As noted in section 2.1 regulations pursuant to the Clean Water Act
currently require,and to RCRA will require, facilities disposing of PCBs
to prepare spill prevention and control plans. These plans should address
prevention and control procedures when a release of PCBs occurs.
Since a trickling filter treatment facility does not specialize in
hazardous waste disposal, it is not anticipated that this type of plant
would be constructed in accordance with RCRA standards for hazardous waste
disposal facilities.
A trickling filter treatment facility should be evaluated very care-
fully with respect to PCB storage and containment. Adequate storage (man-
dated by the PCB Regulations, 40 CFR 761.42) must be available in order for
the treatment facility to be approved.
5.2.3 Economic Factors
Capital costs for a trickling filter facility will depend heavily on
the following unit processes:
a Filtering
Operation of the sedimentation basin
e Sludge dewatering
Feed pretreatment
The major operating and maintenance costs will be for chemicals and labor.
Tables 9 and 10 depict capital and operating costs based on mid-1978
values for a 0.31 m /sec trickling filter wastewater facility located in
Chicago, Illinois.
At this time, it can only be concluded that the costs should be similar
if the process is adapted to handle aqueous streams contaminated with di-
lute amounts of PCBs. Other costs, such as regulatory and special disposal
costs may need to be figured into an economic evaluation if the process is
adapted to PCB disposal. Overall, it appears that moderate capital and
133
-------
OJ
TABLE 9. SUMMARY OF CAPITAL COSTS FOR TRICKLING FILTER PROCESS
(From Hansen et al, 1978)
Coslsl
Capital Cost
Caluyory Module
Site
Structures
electrical
L"(|iii|iuu.>iit
Laud
Total
1 tick I ing filter t 69.400
Sudliiiuntuliun bdsln 29.700
CWificr 995
Sluil'ju ili.'wiluring 14J
cm! 14.710
idl ti:i!il I).330
124.40J
( Ill'llllLill |llllll|l
Y.inl
I ola I
(USlS
Slllltulill Of
Ltlpllill LOilS
UuiUiiij (.
AlliL)
1. 1 .mil lulal of
Lil|llltll COilS
(723.000
241.000
115.000
31.11)0
21J.ODO
107.000
I.4JJ.IOO
141.3031
$ 115.020
li.G .000
22.300
735,000
9)5.000
2'J. 5i 10
l!l/0
4.4'JO
2.6 WJ110
2.020
I/2
/.J'jO
solids (wt/wt) - 20
Sulu = 5.000 tjpin; TSS = t.00 p|)iu;
I Mnl-l'J/ll dollars
« lln I lilinij
*' Al IHIU iiiiuith of direct ii|icratiiuj costs
u lui tiinils itiirlnij toiiblniLliofi dt bt of Cii|)llul costs
Reproduced from
besl available copy.
93,300
25.500
Mb
3,2'JO
6.220
1.520
OiiantHles
Idllll OlIlLT
(It2) VOllUIIL-
34.JOO
Ilu7
4.410
Jl.Jfi2
2.01'J
2.JOO.OOO
1 JO .4/5 4'J.'J'JU 2.300.000
i 6.791.633 ---
60.J2S
330.5H2
7.I'JI.540
-------
TABLE 10. SUMMARY OF FIRST YEAR OPERATING AND MAINTENANCE COSTS
FOR TRICKLING FILTER PROCESS
(From Hansen et al, 1978)
O&H Cost
('aleijoiy
Mniliilu
Type 1
Operator 1
(V/.7//I.I-)
I ahor
Type 2
Opei ill or 2
()9.l9/hr)
Type 3
lalioirr
(lb./6/hr)
Costsl
Energy
llcUrical
(tO OJ5/KUII)
Maintenance
Costs
Chemical Other
Costs Total KUII
(yr)
TiuUlmj filter
Se ill menial ion
lien in
11. ii liter
Sliulije
detMlerlmj
Clii'inical feed
('.lieiiiitdl feud
CliL-inica) pump
riiuniCdl pump
S 1 mlijt pump
Yiinl plplmj
Toldl
OKI! costs
SlllllOldl Of
1 1 ,172
3.911
10.636
2.933
...
...
IB.652
...
I 200
276
755
9110
...
2.139
| 19.301
40.050
1 11.0711
30.637
...
204
202,153
^ ... ,
102
3.102
56.400
35
17
863
60,519
, 9.079
611 .dUO
2.230
7.3'JO
900
IlllO
...
3b3
U9.312
1,770
iltlcll O&M UlSlSS
Ailmiuislralive
IIVL'I IlLMlIf
III. Ill SL'ivlil! dllil
aiiini ll/ullon "
...
...
...
...
...
...
...
...
...
...
j
2.914
2.914
1.610 - 1.611.420
349.000
1.750
1.000
4110
24.657
352.360 --- 1.643,399
f 725.116
145.027
945.499
Keal cslnle laxes
and insurante 1
Toldl first yudr
up LI alliuj costs
...
...
...
. ._
._.
---
...
-«»
143.U3I
1.959.492
Scale 5.000 ijpni
I Mid-1970 dullurs
f AL 20t ul ill i eel opera ttmj cos Is
" Al 101 luleitst over 15 yeais
| Al II of total capital
-------
operating costs would be realized.
5.2.4 Energy Factors
Typically, energy consumption is low for trickling filter wastewater
treatment facilities. The amount of energy required per unit of PCB waste
processed would need to be determined in the overall economic analysis.
5.3 SPECIAL BACTERIAL METHODS
An intensive literature search could not uncover any information about
the usage of any of the special bacterial methods for PCB disposal. Lack
of information means little can be said about important technical factors
at this time. Many of the same technical and environmental problems that
apply to activated sludge and trickling filter processes will also apply
to these other bacterial methods, so that reference should be made to
Sections 5.1 to 5.2.
Because there are insufficient data to indicate the effectiveness of
any of the newer biological disposal methods, further testing is warranted.
Mutant bacterial inoculum in combination with existing treatment systems,
such as activated sludge or trickling filter processes, should be researched
as a viable PCB disposal method.
It is recommended that research be carried out in the following tech-
nical and environmental areas: 1) quantification and assessment of PCB
losses to the environment because of vapor pressure or volatility problems,
2) research to implement the use of the most favorable of the bacterial
methods for PCB disposal, 3) pilot plant construction to attempt the bio-
degradation of PCBs contained in a non-aqueous medium, 4) integrated bio-
logical disposal systems should be developed to utilize the best properties
of each different system, 5) residual toxicity tests should be performed
for each process, and 6) a complete economic feasibility study should be
performed for each system.
136
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6. COMPARISON OF THERMAL AND NON-THERMAL METHODS
As stated earlier, EPA considers non-thermal destruction processes the
"alternative methods" to incineration of PCBs. The basis for evaluation of
an alternative non-thermal system for PCB destruction is its performance
relative to a thermal system. As is 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 boil-
ers". This section will compare several non-thermal methods with the ther-
mal (Annex I incinerators and high efficiency boilers) processes as a basis
for providing guidance on implementing the possible non-thermal methods.
The technical, environmental, economic, and energy factors discussed in
Sections 4 and 5 will provide the basis for this comparison.
As noted in a study by Ackerman et al. (1981), essentially complete
destruction of PCBs can be achieved in both Annex I incinerators and high
efficiency boilers. Generally, incineration of PCB fluids and PCB materials
with concentrations greater than 500 ppm in an Annex I incinerator is
extremely efficient. The same holds true for high efficiency boilers in
which PCB liquids in the 50-500 ppm range may be burned.
None of the alternative methods described in this report are at commer-
cial 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 in-
teresting possibilities. Other methods have only been applied to PCBs in
dilute aqueous solution but are covered because 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 qualitative in nature.
Destruction efficiencies, for those 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 methods meet the
destruction efficiency requirements of the PCB Regulations although there
are other factors that must be considered in evaluating alternative methods.
137
-------
Table 11 compares major characteristics of the thermal (Annex I incin-
eration and high efficiency boiler) PCB destruction processes and the non-
thermal methods.
In general, activated carbon adsorption processes have been primarily
used for the removal of organic materials from dilute wastewater, i.e.,
solutions in which the concentrations of the compounds to be removed are
0.1 percent by weight. Since the lower cutoff limit for PCBs is 50 ppm, it
is not expected that activated carbon adsorption processes could compete
against either Annex I incineration or high efficiency boilers.
With only modest research, activated carbon adsorption methods could
be applied to PCB disposal. However, only liquid PCBs could be treated.
Ultimate disposal of PCB-contaminated charcoal would be by incineration,
volatilization of adsorbed PCBs, recycling the cleaned carbon, and inciner-
ation of the PCB vapors. Based on these considerations, it does not seem
likely that activated carbon adsorption is cost competitive. However, re-
covery of uncontaminated mineral oil may be an offsetting factor.
As stated in Section 4.2, catalytic dehydrochlorination of PCBs has
been successful in the laboratory only. System design parameters and pro-
cessing variables are not well defined at this time. Feed pretreatment,
reactor design, and pollution control will need to be quantified before any
meaningful conclusions can be made.
A direct comparison between a chlorinolysis plant able to handle PCBs
with either Annex I incineration or high efficiency boilers may only be
speculated on at this point. Important system design factors such as re-
actor design and process and pollution control schemes will need to be
developed. Incineration of waste residues may be needed. This could de-
crease the usefulness of this process for PCB disposal. The destruction
efficiency of PCBs in existing chlorinolysis units would be very low since
polychlorinated aromatic compounds are not converted to any appreciable
extent.
The Goodyear process may be adaptable to the conversion of PCBs to non-
toxic products and is capable of being performed on-site in existing equip-
ment. However, the overall conversion of PCBs is only 92 percent which is
138
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TABLE 11. TECHNICAL, ENVIRONMENTAL, AND ECONOMIC COMPARISON OF THERMAL
AND NON-THERMAL PCB DESTRUCTION/CONVERSION METHODS
VO
Current Status
Uestr uclinn or
Conversion Muthod
hiuiux 1 Incineration
Iliqh efFiLiLMicy boilers
Activated Carbon Adsorption
Pi ocessus
Catalytic Ouhyclrochloi mation
Chloi inolysis
Goodyear Process
Microwave Plasma
(donation Processes
Photolytic Piocesses
Sod i uni- Oxygen - Po 1> e thy 1 ene
Glycol
Sunolno Process
Catalyzed Met An Oxidation
Activated Sludge
Trickling Filter
Special liacteiial Methods
1 Method is currently used
Potential for of
Large Scale as
Application PCB
High
High
Iliqh
Medium
Low
High
Medium
Medium
Low
Medium
Nigh
Medium
low
Low
Low
coinnercial ly
Technology
Appl led to
Processing
1
1
3
2
3
3
2
3
2
2
3
2
3
3
3
2 Proven research method only
3 Limited or no data base
PCI! Overall
Destruction
Efficiency
> )9 99Z
>99 99*
Hot anpl icahle
99 fS
1 OU
9^:
9b'i
Not appl icab le
90-9 5i
95t
99H
99<£
Mot applicable
Not appl icahle
Hot appl icable
11
12
13
4 Potential controllable method with minimum environmental impact 14
b Potential solid residue or wastewaler disposal
problem
6 low capital investment and moderate operating costs
7 Moderate capital investment and operating costs
B Large capital investment
9 Laryu capital investment
10 Resource recovery option
and moderate operating
and operating costs
costs
Ib
s
a
9
1
Range Environmental
Feedstock (ppm) Impact
g.l.s
1
a
1.9
1
1
1.9
a
1
1
1
a.l.s
a
a
a
Requi res
Potential
>*iO 4
<50 4
Dilute
amounts 4
>50 5
Mot 4
Applicable
bO 5
50- b(»
and >500
bO-bOO
and >500
bO-bHO
and >500
Dilute
amounts
Dilute
ainniin Is
Dilute
amoiin Is
recycling or disposal
residual tox icily of
.,
,b
,b,ll
,12
,5
t
,b
.12
.Id
12
4
3
12
12
12
of adsorption
by products
Overall
Economic
Impact
9
9
7,10
7.10
9,1(1,15
b,IO
/
-------
far below the 99.9?=+ destruction efficiencies found for Annex I incinerators
and high efficiency boilers. This lower destruction efficiency will detract
from possible advantages, such as product recovery.
PCB destruction by microwave plasma is underdeveloped at this time,
thus direct comparisons to the thermal PCB destruction processes are diffi-
cult to make. Laboratory destruction efficiencies are lower than those for
Annex I incinerators or high efficiency boilers. Process and pollution
control schemes may be very complex because of the elaborate circuitry and
corrosive nature of the waste effluents. These schemes may require excess
capital expenditure making the overall process impractical.
Ul/-ozonolysis has been applied to destruction of PCBs contained in
wastewater only. It is doubtful that this process could be applied effec-
tively to non-aqueous systems. This process can only handle PCBs in the
ppb range, thus direct quantitative comparisons with either Annex I incin-
eration or high efficiency boiler destruction would be meaningless. Although
UV-ozonolysis offers some interesting possibilities for PCB removal from
dilute aqueous streams at fairly low cost and environmental impact, it can-
not be considered as a reasonable alternative to thermal destruction at this
time.
Photolytic PCB destruction methods are not well developed. Quantita-
tive comparisons with thermal destruction methods cannot be made at this
time. As stated earlier, intensive research will need to be carried out to
determine final products and residues resulting from PCB reactions with var-
ious wavelengths of light. Although a 90-95 percent yield of dechlorinated
PCB was found in the experiments performed by Ruzo, et al. (1974), inade-
quate data exist to draw any meaningful conclusions regarding commerciali-
zation of photolytic processes at this time.
The use of molten sodium metal dispersed in polyethylene glycols to
degrade PCBs has barely been researched in the laboratory. Lack of techni-
cal data prohibits any meaningful speculation on the utility of this process
for large scale PCB disposal. Laboratory destruction efficiencies (^95%)
are below those found for both thermal processes. Elaborate pollution con-
trol schemes and safety procedures may be needed because of the evolution
140
-------
of large amounts of hydrogen gas. This could make the process too complex
and expensive to be practical. Optimization studies will need to be car-
ried out before any meaningful conclusions can be drawn.
Technical information gaps and lack of process data prohibit an effec-
tive comparison to be made between the Sunohio PCBX process and the thermal
methods. Destruction efficiencies are not as high, and the method has not
been proven to be reliable on an industrial scale. Product recovery and
reuse as well as mobile unit on-site processing are convenient advantages
of the PCBX process, but may not outweigh the overall lower destruction
efficiency.
The IT Enviroscience catalyzed wet air oxidation process has been re-
searched in the laboratory but has not been applied commercially. Destruc-
tion efficiencies have been found to be between 91-99+%, depending on PCB
concentration, but commercialization is needed to determine large scale
applicability. Destruction efficiencies have not been determined concisely,
thus prohibiting quantitative assessment at this time. Unless a consistent
destruction efficiency >99.99% is achieved it is unlikely that this process
could compete with either Annex I or high efficiency boiler PCB destruction
methods.
The biological processes described in Section 3 have been used primarily
for the removal of organic and inorganic materials from dilute wastewater
where PCB concentrations will be in the ppb range. It is not expected that
any of these methods could compete against either Annex I incineration or
high efficiency boilers. Environmentally, each biological process may re-
quire an excessive number of checks or safeguards because of the possibility
of PCB release to the environment. The possibility of PCB spills and ground-
water contamination appear to be more likely for each biological process
than for either of the thermal destruction methods. An intensive litera-
ture search could not uncover any studies that were aimed at applying these
biological processes to PCB detoxification, of non-aqueous material.
Generally, it is not expected that any existing biological treatment
facilities will be constructed in accordance with RCRA standards for hazard-
ous waste disposal.
141
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7. APPROVAL PROCESS FOR ALTERNATIVE PCB DISPOSAL
METHODS
Chapter 7 provides a suggested process for approval of alternative PCB
disposal methods because:
It is anticipated that nost alternate methods will have
to undergo testing in lieu of a Trial Burn regardless of
whether the material to be disposed of is mineral oil di-
electric fluid from PCB-contaminated transformers of PCB
concentration >50 ppm and >500 ppm (notification only is
necessary for disposal in high efficiency boilers), is
other PCB-contaminated liquids of PCB concentrations >50
ppm and >500 ppm (approval necessary for disposal in high
efficiency boilers), or is any PCB liquid or Item of PCB
concentration >500 ppm (approval is necessary and disposal
can be by Annex I incinerator only).
The approval process for alternate methods described in
the PCB Regulations is not as systematized as it is for
Annex I incinerators and high efficiency boilers.
The suggested approval process presented in Chapter 7 is not technically
detailed because of the large number of processes described in this in-
terim guideline document and because none of the processes are fully de-
fined and at the commercial scale. Reference should be made to process
descriptions presented in Chapter 3 and to process evaluations presented
in Chapters 4 (Physicochemical Methods) and 5 (Biological Methods).
7.1 INTRODUCTION
The PCB Regulations provide (see also Section 2.1) at Section 761.10(a)
that a person who is required incinerate any PCBs or PCB Items, who can
demonstrate that an alternative destruction method exists, and who can
demonstrate that the method can achieve a level of performance equivalent
to Annex I incinerator or high efficiency boilers may submit a written re-
quest to the cognizant Regional Administrator for an exemption from the
Annex I incineration requirements. The applicant must show that the method
will not present an unreasonable risk of injury to health or the environment.
142
-------
On the basis of information in the waiver application and any other avail-
able information, the Regional Administrator may, at his discretion, ap-
prove the use of the alternate method if he finds that the "method provides
PCB destruction equivalent to disposal in an Annex I incinerator and will not
present an unreasonable risk of injury to health or the environment"
Section 761 .10(c)(5)(iii) provides for alternatives to Annex I inciner-
ation or Annex II chemical waste landfills for disposal of dredged materials
and municipal sewage treatment sludges that contain PCBs. The written ap-
plication must, based on technical, environmental, and economic considera-
tions indicate that disposal in an incinerator or chemical waste landfill
is not reasonable and appropriate and that the alternative method will pro-
vide adequate protection to health and the environment. The Regional Admin-
istrator may request other information that he or she believes to be neces-
sary for evaluation of the alternate disposal method.
In summary, the owner/operator of an alternative disposal method must
submit to the cognizant Regional Administrator either a request for a wai-
ver or an application containing required information. The Regional Admin-
istrator is responsible for evaluating the information, determining the need
for additional information, determining appropriate conditions and provi-
sions for an approval, and issuing (or not issuing) an approval.
It is recommended that any alternative PCB disposal method be evaluated
according to the formal procedures described for Annex I incinerators (40 CFR
761.40) which are shown schematically in Figure 15. Appropriate points for
public participation are noted on Figure 15.
7.2 EVALUATION OF EXEMPTION REQUEST AND INITIAL REPORT
Section 761.10(e) provides that any person who is required under Sub-
part B to incinerate PCBs or PCB Items may apply for an exemption if he can
demonstrate that:
An alternative method exists
The method can provide a level of performance equivalent
to that of Annex I incinerators or high efficiency boilers
0 The method will not present an unreasonable risk of injury
to health or the environment
143
-------
OWNER/OPERATOR
APPLIES FOR
EXEMPTION,
PREPARES INITIAL
REPORT AND
SUBMITS IT TO EPA
EPA IDENTIFIES
CONCERNED/
AFFECTED GROUPS/
PUBLIC
REQUEST
ADDITIONAL
DATA
INITIAL REPORT
COMPLETE
EPA PREPARES
CONDITIONS
OF APPROVAL
SECTION 4 4
IS
FACILITY
SUITABLE
ISA
TRIAL BURN
REQUIRED
EPA OUTREACH
INFORM PUBLIC
DO
RESULTS
OF TRIAL BURNS
SHOW SYSTEM CAN
E APPROVED
OWNER/OPERATOR
PREPARES TRIAL
BURN PLAN AND
SUBMITS IT TO EPA
SECTION 4 2
IS TRIAL
BURN PLAN
COMPLETE
ARE TRIAL
BURN DATA
COMPLETE
REQUEST
ADDITIONAL
DATA
IS
COMPLETED
TRIAL BURN PLAN
CCEPTABL
OWNER/OPERATOR
CONDUCTS TRIAL
BURNS AND SUB-
MITS DATA TO EPA
SECTION 4.3
EPA OUTREACH
INFORM PUBLIC
EPA OUTREACH
INFORM PUBLIC
i
t
Figure 15 . Flow chart for approval process for non-thermal methods.
144
-------
Types of information that will permit the Regional Administrator to evaluate
the information supplied include:
Location of the process and the owner/operator
« Detailed description of the process, including general
site plans and design drawings of the process
Engineering reports or other information on the anticipated
performance of the process, including any testing of destruc-
tion capability
« Sampling, monitoring, and analysis equipment and facilities
available
Waste volumes and PCB contents expected to be processed
Any Federal, state, and local permits or approvals granted
Plans and schedules for complying with the approval require-
ments of the PCB Regulations
Chemical and physical properties of the waste(s) to be
processed
« Emission control system(s) and operating data
Process control system operation
Waste storage facilities
The Regional Administrator has the responsibility to evaluate the ex-
emption request in light of the information supplied to determine the need
for additional information, to determine the appropriate conditions and
provisions for an approval, and to issue or deny an approval. On the
basis of the information supplied and any supplemental information request-
ed, the Regional Administrator may require a test in lieu of a Trial Burn.
7.3 EVALUATION OF A TRIAL BURN PLAN
This section presents a brief discussion of and guidelines for evalua-
tion of testing in lieu of a Trial Burn.
The PCB Regulations do not specify the amount of testing to be perform-
ed. On the basis of Best Engineering Judgement and past practice of Trial
Burns, it is recommended that the following test strategy be employed:
One background test while operating the process under
typical conditions with a waste as similar as possible
to the PCB containing waste. Collect all pertinent gas,
liquid, and solid samples and analyze for PCBs and organo-
chlorines (RCLs).
145
-------
Three tests while processing PCB wastes under operating
conditions similar to those of the background test.
Collect all pertinent gas, liquid, and solid samples and
analyze for PCBs and RCLs.
7.3.1 Operational Data
The Trial Burn plan should be evaluated with respect to the adequacy
of descriptions of process control monitoring plans and instrumentation.
Critical assessments should be made of fail-safe instrumentation for shut-
ting off PCB feed in the event of process failures. Critical process para-
meters requiring monitoring are described in Chapters 4 and 5 for each of
the processes discussed in this report.
7.3.2 Monitoring, Sampling, and Analysis
The Trial Burn plan should be evaluated with respect to the adequacy
of descriptions of monitoring, sampling, and analysis methodologies (Appen-
dix B), instrumentation, and capabilities. Test port locations should be
assessed for the capability of permitting the test personnel to withdraw
sufficient and representative samples.
7.4 EVALUATION OF TRIAL BURN DATA
The object of a test in lieu of a Trial Burn of a non-thermal method
is to determine whether it meets the destruction efficiency performance
requirements of Annex I incinerators or high efficiency boilers, as appro-
priate. This section briefly describes methodology for evaluating data re-
sulting from such testing.
Once Testing is completed, data should be reviewed for completeness.
That is, a review of all test data should be made to determine whether all
required data have been taken. This review should be completed before the
test team leaves the site. Table 12 is a brief list of generic kinds of
data appropriate to testing the non-thermal method described in the report.
Once the test team has returned to the laboratory and once analysis
have been completed, data reduction is performed. After data reduction, a
review should be made to assess the validity and representativeness of the
data and results. This review involves the following steps:
146
-------
Engineering assessment - Determine any periods of anomalous
operation, such as start up, shut down, or off-normal opera-
tions. Remove data taken during these periods. These data
might be used to characterize transient effects but should
not be used to characterize normal operations.
TABLE 12. TYPES OF DATA FROM TESTS IN LIEU
OF A TRIAL BURN
I. Feed Rates
Liquid PCBs, in
PCB Items, in
PCB content of PCB Items
Reagents, in
Gas, out
Liquid, out
Solids, out
II. Analytical Results, PCB content of:
Liquids in: PCBs, RCLs
Solids in: PCBs, RCLs
Reagents in: PCBs, RCLs
Liquids out: PCBs, RCLs
Solids out: PCBs, RCLs
III. Gas Analysis (if appropriate)
HC1 content
PCB content
RCL content
Particulate matter
147
-------
Statistical testing - After removal of data from anomalous
operating periods, statistical testing for outliers should
be performed. The Dixon Outlier Test (Dixon and Massen,
1969) is recommended.
t Data quality assessment - Calibration data for test, analysis,
and process instrumentation should be examined for accept-
ability in terms of recency and accuracy. Review of other
quality control checks should be made to assess validity of
the test results.
Data satisfying the above assessment methodology can then be used to
characterize the test in lieu of a Trial Burn. A recent EPA manual (EPA,
1980) of sampling and analysis methods for complying with RCRA testing re-
quirements recommends the use of confidence limits.
The confidence limit is used to characterize the mean of a set of data.
The confidence interval is
u = x + ts
where u = true population mean
x = mean of test results
s = standard deviation about the mean
t = "Student's t" at 95% confidence and (n-1) degrees
of freedom
n = number of values comprising the mean
The confidence interval provides a range of values within which the true
mean of the sampled population should be within the specified degree of
confidence (95% confidence is recommended) upon repeated testing under the
same test conditions.
148
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REFERENCES
ACGIH. 1979. TLVs. Threshold Limit Values for Chemical Substances and
Physical Agents in the Workroom Environment with Intended Changes for 1979.
American Conference of Governmental Industrial Hygienists. Cincinnati,
Ohio.
Ackerman, D.G., L.L. Scinto, P.S. Bakshi, D.L. Anderson, R.G. Delumyea,
R.J. Johnson, G. Richard, and A.M. Takata. 1981. Guidelines for the
Disposal of PCBs and PCB Items by Thermal Destruction. EPA-600/2-81-022.
Ackerman, D.G., H.J. Fisher, R.J. Johnson, R.F. Maddalone, B.J. Matthews,
E.L. Moon, K.H. Scheyer, C.C. Shih, and R.F. Tobias. 1978. At-Sea
Incineration of Herbicide Orange Onboard the M/T Vulcanus. EPA-600/2-78-086.
Anon. Environmental Science and Technology, 8(1): 19, 1974.
Arisman, R.K. 1977. Demonstration of Waste Treatment Processes for the
Destruction of PCBs and PCB Substitutes in an Industrial Effluent. Draft
Report. General Electric Company.
TM
Astro Metallurgical Corp. 1977. Astrol Wet Oxidation Waste Treatment
Systems. Bulletin Nos. WT-77-1 and WT-77-3.
AutotrojMCorporation. 1974. Biosurf Process Information Bulletin.
Biosurf Pilot Plant Program.
Autotrol Corporation. 1971. Application of Rotating Disc Process to
Municipal Wastewater Treatment. EPA Contract Mo. 14-12-810.
Bail in, L.J. 1977. Microwave Plasma Detoxification Process for Hazardous
Wastes, Phase II. Systems Application Evaluation. Lockheed Palo Alto
Research Laboratory. EPA Contract No. 68-03-2190.
Bailin, L.J. and B.L. Hertzler. 1976. Development of Microwave Plasma
Detoxification Process for Hazardous Wastes, Phase I. Lockheed Missiles
and Space Company Inc. October 1976. EPA Contract No. 68-03-2190.
Briggs, G.G. 1973. A Simple Relationship Between Soil Adsorption of
Organic Chemicals and their Octanol/Water Partition Coefficients.
Proceedings of 7th British Insecticide and Fungicide Conference, British
Crop Protection Council, London, P. 83-86.
149
-------
Crosby, D.G. and M.Y. Li. 1969. Herbicide Decomposition. In: Depredation
of Herbicides. P.C. Kearney and D.D. Kaufman, eds. Marcel Dekker, Inc.,
New York.
Beard, J.H., III, and J. Shaum. 1978. Sampling Methods and Analytical
Procedures Manual.
Dixon, W.J. and F.J. Massey, Jr. 1969. Introduction to Statistical Analysis.
3rd Edition. McGraw-Hill. Mew York.
Electronic and Engineering Times. October 29, 1979. PP 1 and 4.
EPA. 1976. PCBs in the United States. Industrial Use and Environmental
Distribution. EPA-560/6-76-005.
EPA. 1977a. Part 129 - Toxic Pollutant Effluent Standards. Standards for
Polychlorinated Biphenyls (PCBs); Final Decision. 40 CFR 129, 42 FR 6531.
EPA. 1977b. Huibregtse, K.R., R.C. Schatz, R.E. Wullschleger, J.H. Moser,
E.R. Bellinger, and C.A. Hansen. Manual for the Control of Hazardous Material
Spills. Volume 1. EPA-600/2-77-277.
EPA. 1978. Polychlorinated Biphenyls. Ambient Water Quality Criteria.
NTIS PB-296 803.
EPA. 1979. Support Document/Voluntary Environmental Impact Statement and PCB
Manufacturing, Processing, Distribution in Commerce, and Use Ban Regulation:
Economic Impact Analysis. Office of Toxic Substances.
EPA. 1980. Test Methods for Evaluating Solid Waste - Physical/Chemical
Methods. EPA Report No. SW-846.
EPRI. 1979a. Electric Power Research Institute. Disposal of Polychlorinated
Biphenyls (PCBs) and PCB-Contarninated Materials. Volume 1. EPRI Report FP-
1207. Vol. 1.
EPRI. 1979b. Electric Power Research Institute. Disposal of Polychlori-
nated Biphenyls (PCBs) and PCB-Contaminated Materials. Volume 2:
Suggested Procedures for Development of PCB Spill Prevention Control and
Countermeasure Plans. EPRI FP-1207. Vol. 2.
EPRI. 1979c. Electric Power Research Institute. Disposal of Polychlori-
nated Biphenyls (PCBs) and PCB-Contaminated Materials. Volume 3: Example
Preparation of a Utility PCB Spill Prevention Control and Countermeasure
Plan. EPRI FP-1207. Vol. 3.
Erickson, M.D., and E.D. Pellizzari. 1979. Analysis of Municipal Sewage
Sludge Samples by GC/MS/Computer for Polychlorinated Biphenyls and Other
Chlorinated Organics. Bulletin of Environmental Contamination and
Toxicology, 22,688-94.
150
-------
Fuller, B., J. Gordon, and M. Kornreich. 1976. Environmental Assessment of
PCBs in the Atmosphere. Mitre Corp. Technical Report MTR-7210, Rev. 1.
Goodyear Tire and Rubber Co. 1980. A Safe, Efficient Chemical Disposal
Method for Polychlorinated Biphenyls.
Griffin, R.A. and E.S. Chian. 1980. Attenuation of Water Soluble Poly-
chlorinated Biphenyls by Earth Materials. EPA-600/2-80-027.
Hague, R. and D. W. Schmedding. 1976. Studies on the Adsorption of
Selected Polychlorinated Biphenyl Isomers on Several Surfaces. Journal of
Environmental Science and Health, 11, 129-137.
Hague, R., D.W. Schmedding, and V.H. Freed. 1974. Aqueous Solubility,
Adsorption, and Vapor Pressure of Polychlorinated Biphenyl Aroclor 1254.
Environmental Science and Technology, 8, 139-142.
Hall-Enos, I., and S. Zelenski. 1980. Test Plan for Evaluation of PCB
Destruction Efficiency in Industrial Boilers. Draft Report. EPA 68-02-3168.
Hansen, W.G. and H.L. Rishel. 1978. Cost Comparisons of Treatment and
Disposal Alternatives for Hazardous Wastes. SCS Engineers, Redmond,
Washington. Volume I.
Hertzler, B.L., D.T. Wadiak, L.M. Law, and L.J. Bail in. 1979. Development
of Microwave Plasma Detoxification Process for Hazardous Wastes. Phase III.
Lockheed Palo Alto Research Laboratory. EPA Contract No. 68-03-2190.
Hutzinger, 0., S. Safe, and V. Zitko. 1974. The Chemistry of PCBs. The
Chemical Rubber Publishing Company, Cleveland, Ohio.
IT Enviroscience. 1980. Catalyzed Wet Oxidation Process for Destruction of
PCBs Process Description and Summary of State-of-the-Art. IT Enviroscience,
Inc., Knoxville, Tennessee.
Kornreich, M., B. Fuller, J. Dorigan, P. Walker, and G. Thomas. 1976.
Environmental Impact of Polychlorinated Biphenyls. Mitre Corp. Technical
Report MTR-7006.
Kranich, W.L., R.B. LaPierre, and A.H. Weiss. 1977. Process for Hydrb-
dechlorination of Polychlorinated Hydrocarbons. Presented at the American
Chemical Society Division of Pesticide Chemistry. 194th National Meeting.
Chicago, Illinois.
Krekeler, H., H. Schmitz, and D. Reblan. The High-Pressure Chlorolysis of
Hydrocarbons to Carbon Tetrachloride. Paper presented at the National
Conference on the Management and Disposal of Residues for the Treatment
of Industrial Wastewaters, Washington, D.C. Feb. 1975.
LaPierre, R.B., E. Biron, D. Wu, L. Guczi, and W.L. Kranich. 1977. Cata-
lytic Hydrodechlorination of Polychlorinated Pesticides and Related
151
-------
Substances. Worcester Polytechnic Inst. Prepared for Municipal Environ-
mental Research Lab. NTIS PB-262 804.
Mauk, C.E., H.W. Prengle, Jr., and J.E. Payne. 1976. Oxidation of
Pesticides by Ozone and Ultraviolet Light. U.S. Army Mobility Equipment
Research and Development Command AO-A028 306/ast.
Mihashi, K.T., M. Hashinaya, J. Dazai, J. Ito and T. Misono. 1975.
Biodegradability of Polychlorinated Biphenyl: 46,65.
Mitchell, L.C., J. Ass. Official Agr. Chem. 4, 643 (1961).
Nisbet, J.C. and A.F. Sarofim. 1972. Rates and Routes of Transport of
PCBs in the Environment. Environ. Health Perspect, 1, p.21.
Oberacker, D.A., and S. Lees. 1977. Microwave Plasma Detoxification of
Hazardous and Toxic Materials. U.S. EPA Report No. USGPO 757-089/7029.
Oku, A., K. Yasufuku, and H. Kataoka. 1978. Chemistry and Industry, 841.
Personal Communication to Don Ackerman by R.A. Miller. Project Engineer,
Research and Development. IT Enviroscience Inc., Knoxville, Tennessee.
Phenobac Technical Data Sheet No. 1377A. 1977. Published by Polybac
Corporation, New York.
Plimmer, J.R. 1972. Principles of Photodecomposition of Pesticides.
Degradation of Synthetic Organic Molecules in the Biosphere, San Francisco.
Published by National Academy of Sciences, Washington, D.C.
Plimmer, J.R. 1978. Approaches to Decontamination or Disposal of Pesti-
cides: Photodecomposition. 174th National Meeting American Chemical
Society, Chicago, Illinois.
Pytlewski, L.L., K. Krevitz, A.B. Smith, E.J. Thome, and F.J. laconianni.
1980. The Reaction of PCBs with Sodium, Oxygen, and Polyethylene Glycols,
EPA-600/9-80-011.
Rosen, J.D. 1971. Photodecomposition of Organic Pesticides. In: Organic
Compounds in Aquatic Environments. S.J. Faust and J.V. Hunter, eds.
Marcel Dekker Inc., New York.
Ruzo, L.O., M.J. Zabik, and R.D. Schoetz. 1974. Photochemistry of Bio-
active Compounds: Photoproducts and Kinetics of Polychlorinated Biphenyls.
J. Agr. Food Chem. 22,2.
S.S.M. Emerging Technology of Chlorinolysis. 1974. Environmental Science
and Technology, 8, 18-19.
152
-------
Scharpenseel, H.W., B.K.G. Theng, and S. Stephan. 1978. Polychlorinated
Biphenyls in Soils: Adsorption, Infiltration, Translocation, and Decom-
position. In Biochemistry and Geomicrobiology, The Terrestrial Environment.
Ann Arbor Science Publishers, Inc., Ann Arbor, MI. V. 2, pp. 619-637.
Sissons, D. and D. Welti. 1971. Structural Identification of Poly-
chlorinated Biphenyls in Commercial Mixtures by Gas-Liquid Chromatography and
Nuclear Magnetic Resonance and Mass Spectroscopy. J. Chromatography, 60, 15.
Stratton, C.L., S.A. Whitlock, and J.M. Allen. 1978. A Method for the
Sampling and Analysis of Polychlorinated Biphenyls (PCBs) in Ambient Air.
EPA-600/4-78-048.
Sunohio Corp. 1980. Sunohio's PCBX Process. Canton, Ohio.
Tennessee Eastman Co. 1979. Destruction of a Dilute PCB-Contaminated
Waste in a Coal-Fired High Efficiency Boiler at Tennessee Eastman Company.
Tucker, E.S., V.M. Saeger and V.M. Mees. 1979. Migration of Polychlorinated
Biphenyls in Soil Induced by Percolating Water. Bulletin of Environmental
Contamination and Toxicology, 13, 86-93.
U.S. Air Force. 1976. Environmental Impact Analysis Process Amendment to
the Final Environmental Statement on the Disposition of Orange Herbicide by
Incineration.
Versar, Inc. 1976. Assessment of Wastewater Management, Treatment, Tech-
nology and Associated Costs for Abatement of PCB Concentrations in Industrial
Effluents.
Wilkinson, R.R., G.L. Kelso, and F.C. Hopkins. 1978. State-of-the-Art
Report: Pesticide Disposal Research, EPA-600/2-78-183.
Zanitsch, R.H., and R.T. Lynch. 1978. Selecting a Thermal Regeneration
System for Activated Carbon. Chemical Engineering, 85, 95-100.
Zelenski, S.G., J. Hall, and S.E. Haupt. 1981. Documentation of the
Permitting Process Regarding the Application to Destroy PCB Waste Oil in an
Industrial Boiler, Volume I. Summary. EPA-600/2-81-033a.
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APPENDIX A
RECOMMENDED TEST METHODS
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A.I RECOMMENDED METHOD FOR SAMPLING STACKS OR DUCTS
EPA (1978) published an interim sampling and analysis manual for PCB
disposal. If an alternate PCB disposal method produces a gaseous emission
stream that could contain PCBs, then it is recommended that the EPA (1978)
method described in Attachment E be employed. This recommended sampling
train is a modified EPA Method 5 train (EPA, 1976) and consists of a heat-
ed probe, heated particulate filter, two water filled impingers, an empty
impinger, an adsorbent tube filled with Florisil, a NaOH filled impinger,
a silica gel filled impinger, a vacuum pump and a dry gas meter. A de-
tailed operating procedure is given in (EPA, 1978). This train has been
used in six recent PCB Trial Burns (EPRI, 1980; Moore, et al., 1980;
Rollins, 1980; Tennessee Eastman, 1979; and Zelenski and Haupt, 1979).
This train is operated isokinetically and traversed across stack dia-
meters according to Method 5 procedures, as detailed in EPA, 1978.
It is recommended that a Method 5 train modified with a water cooled
O
XAD-2 resin trap be used for sampling organochlorine compound emissions
from stacks and ducts of non-thermal PCB disposal processes. XAD-2, a
porous polymer resin, has been extensively chracterized for retention of
organic compounds (Adams, et al., 1977; Gallant, et al., 1978; and
Piecewicz, et al., 1979). XAD-2 has two advantages over Florisil: 1) more
extensive characterization for trapping organic compounds than Florisil
and 2) greater capacity than Florisil. A disadvantage is that XAD-2 is
more difficult to clean (i.e., remove background organic compounds).
Additional characterization of PCB trapping and recovery efficiency
on Florisil should be performed. The work of Haile and Baladi (1977)
showed that the recovery of a dichlorobiphenyl isomer was only 47% under
the following conditions: 1) 4-hour sampling period, 2) ambient tempera-
ture, 3) 20 1pm (0.7 cfm) sampling rate, and 4) 150 mm long x 22 mm dia-
meter trap containing 7.5 g of Florisil. These conditions are essentially
those required by Attachment E of EPA's Interim Manual (EPA, 1978) and used
in the six Trial Burns cited above. It is widely recognized that combus-
tion and environmental ageing (e.g., weathering, photolysis) dechlorinate
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more highly chlorinated PCBs to ones with lower degrees of chlorination.
Thus, the recommended sampling system employing Florisil lacks adequate
trapping efficiency for those chlorobiphenyl isomers (mono- and dichloro-
biphenyls) that ought to be enhanced by non-thermal destruction methods.
A.2 RECOMMENDED METHOD FOR SAMPLING AMBIENT AIR
The method developed by Stratton, et al., (1978) for sampling for
PCBs in ambient air is recommended. This system is based on a standard
high volume sampler modified to incorporate a plug of polyurethane foam
after the filter.
Stratton, et al.,(1978) started with the system developed by Bidelman
and Olney (1974) as a starting point and modified it to improve its per-
formance. The authors describe the modifications made, the laboratory
tests performed to verify the method, and field testing. They also des-
cribe the extensive polyurethane foam cleanup procedure necessary before
it can be used for sampling.
Validation studies performed by Stratton, et al. (1978) indicated that
each PCB isomer has a different retention time in polyurethane foam. Re-
tention times are generally in order of decreasing volatility. Thus, mono-
chlorobiphenyl is the least retained PCB species. They found maximum sampl-
ing period to be about 2 hours at 0.7 m3/min (84 m3 or 3000 ft3). The
authors' conclusions were:
Collection and recovery efficiencies are independent of flow
rate in the range of 0.6 to 1.0 m3/min (21-28 cfm).
Ambient temperature and humidity have no effect on collection
efficiency.
0 Breakthrough or loss of PCB isomers occurs in the order
monochlorobiphenyl, dichlorobiphenyl, and higher substi-
tuted species.
e Quantitative collection (85%) is assured when the sampling
period does not exceed 2 hours.
0 The mean collection efficiency for all tests conducted with
Aroclors 1016 and 1242 was 101 +. 10%.
The authors conducted several field tests of the system. Urban ambi-
ent air in Jacksonville, FL, was sampled. Several samples of 2 to 24 hours
duration were taken over a 24 hour period. Values ranged from 15 ng/m to
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3 33
25 ng/m at one location and from 3 ng/m to 36 ng/m at a second location.
The second location was sampled again with a 6-hour sampling period. No
PCBs were detected. A third test at the second location was performed with
4-hour sampling durations over a 24-hour period. PCB concentrations varied
3 3
from 4 ng/m to 9 ng/m . Several other field tests are also described.
A.3 RECOMMENDED METHODS FOR SAMPLING LIQUIDS
Liquids are typically taken by what is termed grab sampling. A con-
tained liquid is generally taken by tap sampling. A tap, either existing
or installed in a line or container, is opened, and the sample is conducted
into an appropriate container. (Samples for organic analyses are best taken
in amber glass bottles with non-adhesive Teflon lid liners.) If the liquid
is at elevated temperature, it is passed through a cooling coil before en-
tering the sample container. Dipper sampling is appropriate to sampling
sluices, ponds, open discharge streams, and rivers.
A grab sample is representative of the liquid stream only at the time
of acquisition. Consequently, samples need to be taken repeatedly through-
out the duration of a test in order that process variations that give rise
to composition changes in the stream are adequately tested. If numerous
samples are necessary, an automatic composite sampler, such as that des-
cribed by Grant (1978), can be used.
Additional methods of sampling liquids are provided in a recent EPA
manual (EPA, 1980) published in support of physical/chemical testing re-
quired by RCRA.
A.4 RECOMMENDED METHODS FOR SAMPLING SOLIDS
Solids are usually sampled by grab techniques using scoops, shovels,
thiefs, triers, and augers, depending on the nature of the solid materials
lump size, density, consistency, etc. Scoops and shovels are used to
sample granular or powdered material in bins, shallow containers, and con-
veyor belts. A thief sampler is used to sample dry ganules or powders,
the particle size of which is less than one-third the diameter of the thief.
The thief sampler consists of two slotted concentric tubes usually made of
stainless steel or brass. The outer tube has a conical pointed tip which
is used to penetrate the material being sampled. The inner tube is rota-
ted to open the sampler (admit sample) and close the sampler (isolate sample
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for withdrawal). A trier sampler is used to sample sticky solids or soil.
It consists of a tube cut in half lengthwise for most of the length. The
open end is pointed and sharpened for penetration. An auger is used to
sample hard or packed materials and soils. It is made of sharpened spiral
blades attached to a central metal shaft. The spiral blades make for a
"screw like" action as the auger is turned.
When sampling solids, consideration must be given to obtaining a re-
presentative sample. Generally, a solid process effluent stream should
be sampled repetitively during a test to ensure obtaining a representative
sample.
The American Society for Testing Materials has published a procedure
for preparing composite samples of solids (ASTM, 1978). EPA (1980) has
published a manual which covers sampling of solids.
A.5 RECOMMENDED ANALYSIS METHODOLOGY
PCBs have been detected by numerous researchers in all environmental
media. Indeed, these compounds are considered to be ubiquitous. Signifi-
cant levels of contamination have been detected in air, waters, aquatic
sediments, soils, and various biota. There are only limited data on PCB
emissions from combustion sources and incinerators.
There are several factors which complicate the assessment and inter-
pretation of PCB emissions. First, the term PCB applies not to a single
chemical species but to a class of compounds, related by chemical structure
and degree of chlorine substitution on the parent molecule, biphenyl. There
are 209 possible isomers, ranging from 3 monochloro isomers to 1 decachloro-
biphenyl isomer. PCBs are seldom manufactured or used as pure isomers. In
industrial applications, PCBs are made and marketed as mixtures, and each
of these mixtures contains significant fractions of many of the possible
isomers. For example, Aroclor 1242, a commercial PCB product, is comprised
of 54 identified isomers (Hutzinger, et al., 1974). Sissons and Welti
(1971) identified 69 isomers in Aroclor 1254. Such mixtures have been
detected in numerous environmental media. The fact that a class of com-
pounds and not a single identifiable chemical species is to be detected
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and measured greatly increases the complexity of a chemical analysis.
The second complicating factor is that degradation processes change
the relative amounts of isomers in the mixture(s) being disposed of. Thus,
process stream samples will tend to be enriched in the higher volatility,
lower molecular weight PCBs and deficient in the lower volatility, higher
molecular weight PCBs. Thus, interpretation of analytical results can be
difficult.
A third complicating factor is interferences. Many of the non-thermal
processes will emit a substantial number of compounds, many of which ex-
hibit extraction and analytical behavior similar to PCBs. Environmental
samples frequently contain a variety of pesticides which also exhibit ana-
lytical behavior similar to that of PCBs.
A.5.1 General Analytical Methodologies
Gas chromatography (GC) is by far the most widely used analytical
method of separating compounds in the vapor phase, and thus GC provides
qualitative information about a sample.
Various detectors are employed in GC analysis to measure compounds
after separation. The most widely used detector is the electron capture
detector (ECD). The ECD responds, in principle, to electronegative atoms,
such as halogens. The ECD is enormously sensitive and is capable of de-
tecting picogram quantities of halogenated compounds such as PCBs. The
ECD has a limited dynamic range, and its response is linear over only sever-
al orders of magnitude. A major complication in the use of the ECD is that
response factors to various compounds vary over several orders of magnitude,
depend strongly on the degree of halogenation, and depend to a lesser ex-
tent on halogen substitution pattern in isomers with the same degree of
halogenation. Thus, the analyst's experience and proper preparation of
analytical standards are very important in the analysis of PCBs using the
electron capture detector.
A less sensitive, and thus less widely used, detector is the flame
ionization detector (FID). The FID responds, in principle to carbon-
hydrogen bonds. In fully halogenated compounds, there are no carbon-
hydrogen bonds; and the FID has negligible response. The FID is capable
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of detecting nanogram and sub-nanogram quantities of partially halogenated
compounds, such as PCBs.
The most powerful current technique for organic compound analysis is
gas chromatography followed by mass spectrometry (GC/MS). In theory, every
compound will produce a unique mass spectrum. Thus, compounds are sepa-
rated in the GC, and they are identified and quantified by the mass spectro-
meter. In practice, it is difficult or impossible to distinguish the mass
spectra of similar positional isomers. In general, however, GC/MS provides
sufficient identification power for PCB analysis. GC/MS analysis is gen-
erally much less sensitive and considerably more expensive than GC/ECD
analysis although there are techniques for enhancing the sensivity of GC/MS.
Thus, GC/MS is frequently used to confirm the presence of PCBs in a sample
after GC/ECD analysis.
A.5.2 Quantitation
Three general methods of quantifying PCBs have been used either in-
dividually or in combination (EPRI, 1980). These methods are described
below.
A.5.2.1 Pattern Recognition
The most common method of quantifying PCBs in environmental samples
involves comparing the multipeak gas chromatographic elution pattern gen-
erated by the sample (after cleanup procedures to remove pesticides and
other potentially interfering compounds) with the elution patterns of com-
mercial PCB mixtures. (Because one company was the principal manufacturer
of commercial PCBs, each mixture is quite reproducible with respect to
isomeric composition and concentration.) This comparison is relatively
subjective. The decision is then made as to what commercial product most
closely matches the sample pattern. The quantity of PCB present in the
sample is calculated by comparing areas of one or more major peaks in the
sample with matching peaks in the commercial mixture of known concentration.
It is assumed explicitly that all PCB isomers are present in the sample in
the same proportion as in the commercial mixture chosen for quantisation.
This assumption is generally incorrect. Quantitation by pattern recogni-
tion was described in detail by Hutzinger, et al. (1974).
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Pattern recognition has the following advantages:
9 It is well suited to qas chromatographic analysis, which is
simpler and less expensive than GC/MS analysis.
It identifies a commercial mixture which can aid in identi-
fying the source of the contamination.
a It is more sensitive than some GC/MS methods and allows
for more accurate quantisation if samples are not complex
or altered by combustion, weathering, or biological processes.
Pattern recognition has the following disadvantages:
Combustion source and environmental samples will have altered
patterns because of depletion of some isomers. Thus, recog-
nition of a pattern may not be possible. Even if a pattern
is recognizable, quantisation of a PCB mixture with an altered
isomeric or concentration composition would be inaccurate and
potentially misleading.
Many environmental samples also contain various pesticides,
some of which have extraction and chromatographic behavior
similar to PCBs. Thus, pattern recognition may not be
possible, and quantitation may be inaccurate.
A.5.2.2 Derivatization
Derivatization involves converting all PCB isomers in a sample to
decachlorobiphenyl (DCB) by reaction with antimony pentachloride. DCB
is fully chlorine substituted, so that there is only a single isomer.
Derivatization has the following advantages:
It considerably simplifies the analysis by converting all
PCB isomers to a single isomer.
a It considerably reduces the detection limit when an electron
capture detector is used because ECD sensitivity increases
with increasing halogen substitution (although not linearly).
It enables the analyst unequivocally to quantitate DCB.
It minimizes the necessary analytical judegements involved
in the physical measurement of the chromatogram of a multi-
component mixture.
Derivatization has several disadvantages:
As Armour (1972) stated, derivatization to DCB should only
be used as a confirmatory technique because of the possible
presence of interfering compounds.
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9 The result of ":he conversion to and quantification of DCB
is generally reconverted to an amount of the Aroclor mixture
in the original sample. Correction factors range from 0.38
for Aroclor 1221 to 0.79 for Aroclor 1262 (Armour, 1972).
The actual factor cannot be known without accurate knowledge
of the Aroclor originally present. Because of changes in
isomer distribution and concentration in a sample from a
disposal/destruction source, considerable error can be induced
in conversion of a DCB value to the original Aroclor mixture.
9 The method is subject to false positives. Haile (1976) found
several extracts of samples taken at a coal-fired utility
plant that produced DCB upon perchlorination in which PCBs
could not be confirmed by GC/MS analysis of unperchlorinated
portions of the sample. Haile concluded that the extracts
contained biphenyl and/or related aromatic compounds that
could be converted to DCB and that GC/MS was necessary for
verification of PCBs. EPRI (1980) noted false positives in
the Trial Burn at ENSCO.
A.5.2.3 Measurement of Individual Components--
Because of the disadvantages of pattern matching and derivatization,
Webb and McCall (1973) proposed analysis by GC using ECD detection using
Aroclor standards in which the quantitative composition of each peak is
known. Using GC/MS and GC with an electrolytic conductivity detector,
Webb and McCall determined the empirical formula and the amount of chlorine
represented by each peak in a series of Aroclor standards.
Eichelberger, et al. (1974) proposed a GC/MS method in which selected
ions were monitored. Their study indicated that single ions characteris-
tic of mono- through hexachlorobiphenyl could be monitored and thus pro-
vide enhanced sensitivity over the usual method of scanning a large mass
range (e.g., 50-500 amu) repetitively during the chromatogram. During the
usual mode, the MS spends only a very small fraction of the total scan time
focusing ions of each m/e ratio. Thus, most of the information provided
by the MS (as much as 95-99%) is not relevant. When the MS is made to
focus repetitively on a limited number of ions of known significance, the
amount of time spent counting each of the limited number of ions is greater
than when all ions are scanned. Sensitivity is thus enhanced. In a library
search of mass spectra, very few and only minimally interfering compounds
were found.
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Levins, et a!., (1979) examined methods used for PCB analysis, recom-
mended a procedure, and performed verification testing. Their work was
performed because conventional PCB analytical methods are frequently dif-
ficult to apply to samples derived from combustion sources or ambient air.
Their approach is fully described. It is a GC/MS technique involving the
following steps:
Acquire GC/MS data in PCB subset mass windows large enougth
to encompass all isotope clusters.
Examine selected mass spectra to verify the presence of PCBs
by their chlorine isotope abundance patterns.
Generate mass chromatograms from a single mass chosen to
represent each chlorobiphenyl isomer (e.g., mono-, di-,
tri-, etc., chlorobiphenyl).
Integrate areas in each mass chromatogram only in the
retention time region corresponding to each chlorobiphenyl
isomer.
Quantitate from selected peaks in Aroclor reference standards
or with pure isomers.
Advantages of the techniques for measuring individual isomers are:
Accuracy is not dependent on correct identification of an
Aroclor mixture. Thus, samples altered by a combustion
source, weathering, or metabolism can be quantitated as
accurately as pure standards.
They eliminate the additional analytical step of perchlori-
nation and the problem of false positives.
Disadvantages of the technique for measuring individual isomers are:
There is a reduction in sensitivity relative to GC-ECD.
Repetitive scanning GC/MS can involve a sensitivity loss
of 103-io5 (Eichelberger, et al., 1974). Selective ion
monitoring (Eichelberger, et al., 1974 and Levins, et al.,
1979) results in an increase in sensitivity, but GC/ECD is
still more sensitive.
GC/MS analyses are considerably more expensive than GC/ECD
analyses.
A.5.3 Recommended Method
It is recommended that the methodology specified in EPA's Interim
guide (EPA, 1978) be employed for analyses of samples taken during PCB
Trial Burns. The Florisil trap or polyurethane foam (sample or blank)
trap is extracted with hexane in a soxhlet, cooled, and then concentrated
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to about 5 ml. Contents of the first two (water filled) impingers are ex-
tracted with hexane, dried by passing through columns filled with anhydrous
Na2S04< and added to the Florisil extract. The probe and impingers are
rinsed with acetone then hexane. The rinses are dried with anydrous Na^SO,
and added to the combined extracts. The combined extracts are then cleaned
by extracting with concentrated H^SO, (if the cleaned extract is still
colored, liquid chromatography on Florisil can be used). Samples of solid
and liquid streams are similarly extracted with hexane. Extracts are
made to 25 ml volume and split into four portions: three 5-ml volumes for
perchlorination and one 10-ml aliquot for confirmation studies by GC/MS.
After perchlorination, the solution is extracted four times with hexane
and made to 5 ml. Analysis for decachlorobiphenyl is performed by GC-ECD.
Chromatographic parameters are:
Chromatograph - Any suitable instrument.
J CO
Detector - Electron capture, H or N.
o Column - 1.8 m x 2 mm ID, 3% OV-210 on Supelcoport, 100/120
mesh.
Temperatures - Column 280°C, others not specified.
Carrier gas - Not specified (N2 or He), 30 ml/min.
Detection limit - Not specified, but standards of 25 to
50 pg/yl are suggested. The overall detection limit is
specified as 10 ng DCB in a 5 ml perchlorination aliquot.
This indicates a minimum detection limit of 2 pg/ul injected.
Results are reported in terms of ng DCB per cubic meter of combustion
gas, per liter of liquid, or per kg of solid sampled. GC/MS is used to
verify the presence of PCBs by pattern matching with Aroclor mixtures.
The precision of the DCB analysis is stated to be 10-15%, and recovery of
PCBs through the entire sampling and analysis procedure is stated to be
85-952 (EPA, 1978).
It must be repeated that the perchlorination procedure is subject to
false positives. Therefore, the importance of adequate test strategy and
procedural (sampling and analysis) and reagent blanks cannot be overstated.
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REFERENCES
Adams, S.J., K. Menzies, and P.L. Levins. 1977. Selection and Evaluation
of Sorbent Resins for the Collection of Organic Compounds. EPA-600/7-77-044.
Armour, J.A. 1972. Quantitative Perchlorination of Polychorinated
Biphenyls as a Method for Confirming Residue Measurement and Identifi-
cation. J. Official Analytical Chemists, 56, 987.
ASTM. 1978. D346-78 Standard Method of Sampling Coke for Analysis.
Part 26, pp. 213-ff.
Bidelman, T.F. and C.E. Olney. 1974. High Volume Collection of Atmospher-
ic Polychorinated Biphenyls. Bull. Environ. Contam. Toxicol., 2, 5.
Eichelberger, J.W., I.E. Harris, and W.L. Budde. 1974. Analysis of the
Polychorinated Biphenyl Problem. Application of Gas Chromatography-Mass
Spectrometry with Computer Controlled Repetitive Data Acquisition from
Selected Specific Ions. Anal. Chem., 46, 227.
EPA. 1976. 40 CFR Part 60. Federal Register, Vol. 41, No. Ill, 8
June, 1976, pp. 23076-23083.
EPA. 1978. Sampling Methods and Analytical Procedures Manual for PCB
Disposal: Interim Report. J.H. Beard, III, and J. Schaum. U.S. EPA
Office of Solid Waste.
EPA. 1980. Test Methods for Evaluating Solid Waste. Physical/Chemical
Methods. Report No. SW-846.
EPRI. 1980. Disposal of Polychlorinated Biphenyls (PCBs) and PCB-
Contarrrinated Materials. Volume 4. Test Incineration of Electrical
Capacitors Containing PCBs. Electric Power Research Institute Report
No. FP-1207, Volume 4, September.
Gallant, R.F., J.W. King, P.L. Levins, and J.F. Piecewicz. 1978.
Characterization of Sorbent Resins for Use in Environmental Sampling.
EPA-600/7-78-054.
Grant, D.M. 1978. Open Chemical Flow Measurment Handbook. Instrumen-
tation Specialties Company.
Haile, C. 1976. Iriterlaboratory Verification Analysis. Midwest Research
Institute, Final Report on EPA Contract 68-02-1399.
Haile, C.F. and E. Baladi. 1977. Methods for Determining the Poly-
chlorinated Biphenyl Emissions from Incineration and Capacitor and
Transformer Filling Plants. EPA-600/4-77-048.
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Hutzinger, 0., S. Safe and V. Zitko. 1974. The Chemistry of PCBs. CRC
Press, Cleveland, Ohio.
Levins, P.L., C.E. Rechsteiner and J.L. Stauffer. 1979. Measurement of
PCB Emissions from Combustion Sources. EPA-600/7-79-047.
Moore, D.R., R.W. Korner, W.F. Wright, and D.G. Ackerman. 1980. Plan
for Emissions Testing at Two Commercial Incinerators: Rollins Environ-
mental Services, Inc. Deer Park, TX, and Energy Systems Company, El
Dorado, AK. Draft. EPA Contract 68-02-3174, Work Assignment No. 31.
Piecewicz, J.F., J.C. Harris, and P.L. Levins. 1979. Further Characteri-
zations of Sorbents for Environmental Sampling. EPA-600/7-79-216.
Rollins. 1980. The PCB Incineration Test Made by Rollins Environmental
Services (TX) at Deer Park, TX, November 12-16, 1979. Report by Rollins
Environmental Services to EPA Region VI, 15 August.
Sissons, D. and D. Welti. 1971. Structural Identification of Poly-
chlorinated Biphenyls in Commercial Mixtures by Gas-Liquid Chromatography,
Nuclear Magnetic Resonance and Mass Spectroscopy. J. Chromatog., 60, 150.
Stratton, C.L., S.A. Whitlock and J.M. Allen. 1978. A Method for the
Sampling and Analysis of Polychlorinated Biphenyls (PCBs) in Ambient Air.
EPA-600/4-78-048.
Tennessee Eastman. 1979. Destruction of a Dilute PCB-Contaminated
Waste in a Coal-Fired High Efficiency Boiler at Tennessee Eastman Company.
Webb, R.G. and A.C. McCall. 1973. Quantitative PCB Standards for
Electron Capture Gas Chromatography. J. Chromatog. Sci., 11,366.
Zelenski, S.G. and S. Haupt. 1979. Evaluation of PCB Destruction in
Industrial Boilers. EPA Contract No. 68-02-2607. Task No. 33. Draft
Report.
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