EPA/600/A-94/225
MINIMIZATION OF TOXIC COMBUSTION BYPRODUCTS:
REVIEW OF CURRENT ACTIVITIES
by
C.C. Lee and 6.L. Huffman
Presented at the
1993 Pacific Basin Conference on Hazardous Waste
Honolulu, Hawaii
November 8-12, 1993
U.S. Environmental Protection Agency
Office of Research and Development
Office of Environmental Engineering and Technology Demonstration
Risk Reduction Engineering Laboratory
Waste Minimization, Destruction and Disposal Research Division
Thermal Destruction Branch
Thermal Processes Section
Cincinnati, Ohio 45268
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MINIMIZATION OF TOXIC COMBUSTION BYPRODUCTS:
REVIEW OF CURRENT ACTIVITIES
C. C. Lee and G. L. Huffman
U.S. Environmental Protection Agency
Cincinnati, Ohio
ABSTRACT
In general, toxic combustion byproducts (TCBs) are the unwanted residues
remaining in flue gases, combustion ashes, and wastewaters from the operation
of an incineration or combustion facility. If a combustor is not well
designed and operated, it may emit too high a level of TCBs. Categories of
TCBs and some example constituents are as follows:
(1) Acid gas: HC1, NOx and S02;
(2) Organics: Hydrocarbons such as dioxlns and furans {PCDDs and
PCDFs);
(3) Particulates: Trace metals (conventional metals and radioactive
metals) and soots;
(4) Contaminants in ash; and
(5) Contaminants 1n spent wastewater
Pollutants 1n Category (2) above are generally considered to be the products
of incomplete combustion (PICs) 1n the field of hazardous waste incineration
in the United States.
The issue of TCBs has been one of the major technical and sociological issues
surrounding the implementation of Incineration as a waste treatment
alternative. Because of the complexity and controversy, EPA's Dr. C.C. Lee
conceived of and initiated the International Congress on Toxic Combustion
Byproducts {ICTCB) to provide a forum for scientists to discuss the issues of
and controls for TCBs in 1989. This Paper focuses on the review of the 1989
ICTCB (the First ICTCB) activities. The 1991 (the Second) and 1993 (the
Third) ICTCB activities will be reviewed at another time. The objective of
these reviews 1s to discuss:
(1) What have we learned from the ICTCB conferences;
(2) What can we use from what we have learned; and
(3) What improvement 1n the ICTCBs 1s needed.
INTRODUCTION
The control of emissions of toxic combustion byproducts (TCBs) 1s "now" one of
the major technical and sociological Issues surrounding the Implementation of
incineration as a waste treatment alternative. The current RCRA regulation on
"destruction and removal efficiency" has led to the unfortunate public
misconception of incineration as a "landfill 1n the sky." As a result, the
public has developed the so-called "NIMBY" (not in my back yard) attitude
which makes the siting of an incineration facility extremely difficult.
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National organizations have been established to campaign against incineration.
Local communities often mobilize against it. It 1s ironic that Incineration
has often been selected to be the most effective technology to treat toxic
waste, yet, it probably has maximum opposition from the public, compared to
alternative technologies. While pollution prevention approaches have the
potential to substantially reduce the quantity of hazardous waste generated,
it is unlikely that it can be totally eliminated. Therefore, some hazardous
waste will likely continue to be generated, as long as Industry is
continuously manufacturing products for human consumption. The question then
becomes "Why not use one of the most effective and environmentally protective
technologies (incineration) to dispose of these toxic wastes?"
One obstacle to the widespread adoption of Incineration has been the issue of
toxic combustion byproducts (TCBs). Categories of TCBs and some example
constituents are as follows [Categories (2) and (3) contain the most critical
components of concern]:
(1) Acid gas: HC1, NOx and S02;
(2) Organics: Hydrocarbons such as dioxins and furans (PCDDs and
PCDFs) [This Category is generally referred to as the products of
incomplete combustion (PICs)];
(3) Particulates: Trace metals (conventional metals and radioactive
metals) and soots;
(4) Contaminants 1n ash; and
(5) Contaminants in spent wastewater
The authors began to write a series of TCB-related papers in 1988 to search
for TCB solutions (Lee-7/88; 8/88; 4/90; 5/90; 11/90; 2/91; 4/91; 8/91).
Then, EPA's Dr. C. C. Lee Initiated the International Congress on Toxic
Combustion Byproducts (ICTCB) in 1989 to provide a forum for scientists to
discuss TCB issues.
THE THEME OF THE ICTCB
The theme of the First ICTCB and all those to follow was summarized in the
Opening Remarks of the first ICTCB Chairman, EPA's Dr. C. C. Lee. His remarks
are highlighted as follows:
• Need: To address the TCB issues. They cover the whole spectrum
of issues ranging frora TCB formation to controls, from regulation
development to compliance and enforcement, from technology
development to performance assurance, from the community right-to-
know to public participation, etc.
• Scope: To encompass all waste incineration and fossil fuel
combustion-related subjects. Both waste incineration and fossil
fuel combustion have the same metals problems, similar chlorine-
in-feed problems, etc.
• Approach: To provide a forum for all concerned parties to discuss
issues and to develop answers.
• Output: To advance the understanding, development, and application
of combustion/incineration and pollution control technologies for
the reduction of risks from waste incineration and fossil fuel
combustion operations.
2
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CHRONICLE OF EVENTS
• The First ICTCB was held at the University of California at Los
Angeles (UCLA), August 2-4, 1989. Twenty four (24) presented
papers were later selected, peer-reviewed and published in a
special edition of the Combustion Science and Technology (CST)
journal in Volume 74, Numbers 1-6, 1990 (CST90-pxx).
• The Second ICTCB was held at the University of Utah, Salt Lake
City, Utah on March 26-29, 1991. Twenty eight (28) presented
papers were later selected, peer-reviewed and published in a
special edition of the Combustion Science and Technology (CST)
journal in Volume 85, Numbers 1-6, 1992.
• The Third ICTCB was held at the Massachusetts Institute of
Technology (MIT), Cambridge, Massachusetts on June 14-16, 1993.
Similar to the First and the Second ICTCB, selected papers will be
published in a special edition of the CST journal (probably 1n
1994).
• The Fourth ICTCB will be held at the University of California at
Berkeley in the summer of 1995 (specific date will be selected in
the near future). Those who wish for his/her name to be included
in the future mailing list should contact EPA's Ms. Georgia
Dunaway; her address 1s: U.S. EPA, Risk Reduction Engineering
Laboratory, 26 West Martin L. King Dr. Cincinnati, Ohio 45268,
telephone number 513-569-7650, fax number 513-569-7549.
SPONSORING ORGANIZATIONS
The sponsoring organizations for the various ICTCBs are provided in Table 1.
TABLE 1. SPONSORING ORGANIZATIONS
ICTCB-
(Alphabetic Order)
89
91
93
Coalition For Responsible Waste Incineration, Washington
DC
X
X
EPA, Risk Reduction Engineering Laboratory, Cincinnati,
Ohio
X
X
X
Gas Research Institute, Chicago, Illinois
X
X
Industrial Technology Research Institute, Hs1n Chu,
Taiwan
X
National Institute of Environmental Health Sciences,
Research Triangle Park, North Carolina
X
X
National Science Foundation/Advanced Combustion
Engineering Research Center, University of Utah
X
X
3
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National Science Foundation/Engineering Research Center
for Hazardous Substances Control, UCLA
X
Northeast Hazardous Substance Research Center, Newark, NJ
X
Sandia National Laboratory, Livermore, California
X
X
Southern California Edison, Los Angeles, California
X
X
SUMMARY OF THE FIRST CONGRESS
This Paper summarizes information presented at the 1989 ICTCB, the First
International Congress. It provides the highlights of major areas/papers
presented. The major areas are grouped under the following headings: (1)
Overview; (2) Regulations; (3) Combustion systems; (4) Liquid combustion; (5)
Solid combustion; (6) Metals emissions; (7) Organic emissions; (8) PAH and
soot emissions; (9) Acid gas emissions;(10) Simulations and transport;(11) TCB
control; (12) Monitoring, sampling and analysis; and (13) Risk assessment.
Overview
J. Skinner, then Acting Deputy Assistant Administrator of EPA's Office of
Research and Development, provided the Congress with a description of EPA's
research and development direction. He indicated that the primary
responsibility for technology innovation and development resides in the
private sector. EPA's role is to stimulate and guide private sector
development by identifying needs and by providing technical and logistical
support where possible (ICTCB89-si).
T. Oppelt, Director of EPA's Risk Reduction Engineering Laboratory, then
provided EPA's mission. He said that EPA's mission must embody the concepts
of risk prevention and reduction. These concepts involve a hierarchy of
policy and technical tools that support national efforts to: (1) minimize the
amounts of pollutants generated; (2) recycle or reuse pollutants; (3) control
the materials or wastes that cannot be recycled or reused; and (4) minimize
human and environmental exposures to any remaining wastes or pollutants. For
many materials or wastes that cannot be prevented or recycled, he Indicated
that incineration will be the control technology of choice. He also indicated
that substantial, continued research in Improving the effectiveness of
hazardous waste incineration, especially with regard to the importance of PICs
and metals emissions, is required of EPA, academla, and Industry to resolve
the paradox which has arisen from the public's objection to the use of
incineration technology --- in that the technology which often provides the
greatest level of control (destruction) of toxic materials (incineration)
often has the least amount of public support (ICTCB89-S4).
Regulations
Environmental regulations are the driving forces for the protection of the
environment. R. Holloway of EPA's Office of Solid Waste discussed his
regulatory work aimed at the "Burning of Hazardous Waste in Boilers and
Industrial Furnaces (BIF)R so that their emissions of TCBs can be controlled.
The BIF rules were later published in the Federal Register, Vol. 56, No. 35,
Thursday, February 21, 1991 and were codified in 40 CFR Parts 260, et al. In
4
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brief, the BIF rules set standards to control the emissions of the following
species from the operation of hazardous waste-burning 8IFs (ICTCB89-S1):
(1) Hydrogen chloride (HC1);
(2) Carbon monoxide (CO) which is used as the surrogate to
control PIC emissions; and
(3) Metals including: (A) four (4) carcinogenic metals [arsenic (As);
beryllium (Be); chromium (Cr); and cadmium (Cd)]; and (B) six (6)
toxic metals [antimony (Sb); barium (Ba); lead (Pb); mercury
(Hg); silver (Ag); and thallium (Tl)].
Almost parallel to the development of the BIF rules, the U.S. Congress passed
the Clean Air Act Amendments 1n 1991. One of the key elements 1n the
Amendments 1s the control of the 189 hazardous air pollutants (HAPs) from
major sources (see Table 2 for the HAP listings). The main reason for
providing this listing 1s to provide a reference so that if specific PICs have
to be Identified 1n the future, the HAP compounds can be used as the first
step in the identification process.
Combustion Systems
0. Smith, et al., of UCLA presented their work on the incineration of a
surrogate (sulfur hexafluoride, SF6) In a low speed "dump" combustor. The
paper shows that good SF6 DREs, in some cases exceeding the detection limit of
nearly six 9's, can be achieved (CST90-pl99).
Most presenters in this Session did not seek to have their papers submitted
for CST peer-review publication. R. Seeker and C. Koshland, Editors of this
CST edition (CST90-pi), summarized their (presenters) efforts as follows:
Mike Heap from the Energy and Environmental Research Corporation
provided an overview of combustion systems and byproduct
emissions. Robert Adrian from the California A1r Resources Board
presented results of extensive emissions testing from medical
waste incinerators while Ed Lawless of the Midwest Research
Institute provided an overview of EPA studies on hazardous waste
Incinerator emissions. Finally, Victor Engleman of the Science
Applications International Corporation provided an overview of
innovative Incineration systems. Rubin of Carnegie Mellon
University discussed evaluation models that allow an assessment of
emissions of chemical substances.
Liouid Combustion
J. Dalplanque, et al., of the University of California at Irvine presented the
Issues surrounding the numerical modeling of multlcomponent droplets
vaporization and combustion of hazardous liquid wastes (ICTC889-S5).
J. Kramllch of the Energy and Environmental Research Corporation discussed
bench-scale testing of a turbulent spray flame reactor. His work provided
further understanding of characteristics such as spray quality, the
stoichiometry impact on DRE, use of CO as an Indicator of destruction
efficiency, etc (CST90-pl7).
5
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TABLE 2. HAZARDOUS AIR POLLUTANTS
CAS No. ORDER |
ALPHABETIC ORDER
50000
Formaldehyde
75070
Acetaldehyde
51285
Dinitrophenol(2,4-)
60355
Acetamide
51796
Ethyl carbamate (Urethane)
75058
Acetonitrile
53963
Acetylaminofluorene(2-)
98862
Acetophenone
56235
Carbon tetrachloride
53963
Acetylaminofluorene(2-)
56382
Parathion
107028
Acrolein
57147
Dimethyl(1,1-) hydrazine
79061
Acrylamide
57578
Propiolactone (beta-)
79107
Acrylic acid
57749
Chlordane
107131
Acrylonitrile
58899
Lindane (all isomers)
107051
Allyl chloride
59892
Nitrosomorphol ine(n-)
92671
Aminobiphenyl(4-)
60117
Dimethyl aminoazobenzene
62533
Aniline
60344
Methyl hydrazine 1
90040
Anisidine(o-)
60355
Acetamide R
Antimony compounds
62533
Aniline |
Arsenic compounds (inorganic
including arsine)
62737
Dichlorvos
1332214
Asbestos
62759
Nitrosodimethylamine(n-)
71432
Benzene (including benzene from
gasoline)
63252
Carbaryl
92875
Benzidine
64675
Diethyl sulfate
98077
Benzotrichloride
67561
Methanol
100447
Benzyl chloride
67663
Chloroform
Beryllium compounds
67721
Hexachloroethane
92524
B1phenyl
68122
Dimethyl formamide
117817
Bis(2-ethylhexyl)phthalate (DEHP)
71432
Benzene (including benzene from
qasoline)
542881
Bis(chloromethyl)ether
71556
Methyl chloroform (1,1,1-
Trichloroethane)
1 75252
Bromoform
72435
Methoxychlor
1 106990
Butadiene(l,3-)
74839
Methyl bromide (Bromomethane) 1
Cadmium compounds
74873
Methyl chloride (Chloromethane)
156627
Calcium cyanamide
74884
Methyl iodide (Iodomethane)
105602
Caprolactam
75003
Ethyl chloride (Chloroethane)
133062
Captan
75014
Vinyl chloride
63252
Carbaryl
6
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TABLE 2. HAZARDOUS AIR POLLUTANTS
CAS No. ORDER 1
ALPHABETIC ORDER
75058
Acetonitrile |
75150
Carbon disulfide
75070
Acetaldehyde
56235
Carbon tetrachloride
75092
Methylene chloride
(Dichloromethane)
463581
Carbonyl sulfide
75150
Carbon disulfide
120809
Catechol
75218
Ethylene oxide
133904
Chloramben
75252
Bromoform
57749
Chlordane
75343
Ethylidene dichloride (1,1-
Dichloroethane)
7782505
Chlorine
75354
Vinylidene chloride (1,1-
Dichloroethylene)
79118
Chloroacetic acid
75445
Phosgene
532274
Ch1oroacetophenone(2-)
75558
Propylenimine(l,2-) (2-Methyl
aziridine)
108907
Chlorobenzene
75569
Propylene oxide
510156
Chiorobenzilate
76448
Heptachlor
67663
Chloroform
77474
Hexachlorocyclopentadiene
107302
Chloromethyl methyl ether
77781
Dimethyl sulfate I
126998
Chloroprene
78591
Isophorone 1
Chromium compounds
78875
Propylene dichloride (1,2- 1
Dichloropropane) 1
Cobalt compounds
78933
Methyl ethyl ketone (2-Butanone) 8
Coke oven emissions
79005
Trichloroethane(l,l,2-) !
108394
Cresol(m-)
79016
Trichloroethylene
95487
Cresol(o-)
79061
Acrylamide
106445
Cresol(p-)
79107
Acrylic acid
1319773
Cresols/Cresylic acid (isomers and
mixture)
79118
Chloroacetic acid
98828
Cumene
79345
Tetrachloroethane(l,l,2,2-)
Cyanide compounds
79447
Dimethyl carbamoyl chloride
1 94757
D(2,4-), salts and esters
79469
Nitropropane(2-)
3547044
DDE
80626
Methyl methacrylate
334883
Dlazomethane
82688
Pentachloroni trobenzene
(Quintobenzene)
132649
Dibenzofurans
84742
Dibutylphthalate
96128
Dibromo(l,2-)-3-chloropropane
85449
Phthal1c anhydride
84742
Dibutylphthalate
87683
Hexachlorobutadiene
106467
Dichlorobenzene(l,4-)(p)
7
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TABLE 2. HAZARDOUS AIR POLLUTANTS
CAS No. OROER |
ALPHABETIC ORDER
87865
Pentachlorophenol
91941
Dichlorobenzidene(3,3-)
88062
Trichlorophenol (2,4,6-)
111444
Dichloroethyl ether (Bis(2-
chloroethyl)ether)
90040
Anisidine(o-)
542756
Dichloropropene(l,3-)
91203
Naphthalene
62737
Dichlorvos
91225
Quinoline
111422
Diethanolamine
91941
Dichlorobenzidene(3,3-)
64675
Diethyl sulfate
92524
Biphenyl
121697
Diethyl(n,n-) aniline (n,n-
Dimethylaniline)
92671
Ami nob1 phenyl(4-)
119904
D1methoxybenzidine(3,3-)
92875
Benzidine
60117
Dimethyl aminoazobenzene
92933
Nitrobiphenyl(4-)
79447
Dimethyl carbamoyl chloride
94757
0(2,4-), salts and esters
68122
Dimethyl formamide
95476
Xylenes(o-)
131113
Dimethyl phthalate
95487
Cresol(o-)
77781
Dimethyl sulfate
95534
Toluidine(o-)
1 57147
Dimethyl(1,1-) hydrazine
95807
To1uene(2,4-) diamine
1 119937
Dimethyl(3,3'-) benzidine
95954
Trichlorophenol (2,4,5-)
534521
Dinitro(4,6-)-o-cresol, and salts
96093
Styrene oxide
51285
Din1trophenol(2,4-)
96128
Di bromofl,2-)-3-chloropropane
121142
Dinitrotoluene(2,4-)
96457
Ethylene thiourea
123911
Dioxane(l,4-) (1,4-
Diethyleneoxide)
98077
Benzotrichloride
122667
Diphenylhydrazine(l,2-)
98828
Cumene
106898
Epichlorohydrin (l-chloro-2,3-
epoxypropane)
98862
Acetophenone
106887
Epoxybutane(l,2-)
98953
Nitrobenzene
140885
Ethyl acrylate
100027
Nitrophenol(4-)
100414
Ethyl benzene
100414
Ethyl benzene
51796
Ethyl carbamate (Urethane)
100425
Styrene
75003
Ethyl chloride (Chloroethane)
100447
Benzyl chloride
106934
Ethylene dibromlde (Dibromoethane)
101144
Methylene(4,4-) bis(2-
chloroaniline)
107062
Ethylene dichlorlde (1,2-
Dlchloroethane)
101688
Methylene diphenyl diisocyanate
(MDI)
107211
Ethylene glycol
101779
Methylenedianiline(4,4'-)
151564
Ethylene imine (Aziridine)
8
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TABLE 2. HAZARDOUS AIR POLLUTANTS
CAS No. ORDER |
ALPHABETIC ORDER
105602
Caprolactam
75218
Ethylene oxide
106423
Xylenes(p-)
96457
Ethylene thiourea
106445
Cresol(p-)
75343
EthylIdene dlchloride (1,1-
Dichloroethane)
106467
D1chlorobenzene(l,4-)(p)
Fine mineral fibers
106503
Phenylenediamine(p-) |
50000
Formaldehyde
106514
Quinone I
Glycol ethers
106887
Epoxybutane(l,2-)
76448
Heptachlor
106898
Epichlorohydrln (l-chloro-2,3-
epoxypropane)
118741
Hexachlorobenzene
106934
Ethylene dlbromide
(Dibromoethane)
87683
Hexachlorobutadlene
106990
Butadiene(l,3-)
77474
Hexachlorocyclopentadi ene
107028
Acrolein
67721
Hexachloroethane
107051
Allyl chloride
822060
Hexamethylene-1,6-d11socyanate
107062
Ethylene dichloride (1,2-
Dichloroethane) I
680319
Hexamethylphosphoramide
107131
Acrylonitrile
110543
Hexane
107211
Ethylene glycol
302012
Hydrazine
107302
Chloromethyl methyl ether
7647010
Hydrochloric acid
108054
Vinyl acetate
7664393
Hydrogen fluoride (Hydrofluoric
acid)
108101
Methyl isobutyl ketone (Hexone)
7783064
Hydrogen sulfide
108316
Maleic anhydride
123319
Hydroquinone
108383
Xylenes(m-)
78591
Isophorone
108394
Cresol(m-)
Lead compounds
108883
Toluene
58899
Lindane (all Isomers)
108907
Chlorobenzene
108316
Maleic anhydride
108952
Phenol
Manganese compounds
110543
Hexane
Mercury compounds
111422
Diethanolamine
67561
Methanol
111444
Dlchloroethyl ether (B1s(2-
chloroethyl)ether)
72435
Methoxychlor
114261
Propoxur (Bayqon)
74839
Methyl bromide (Bromomethane)
117817
B1s(2-ethylhexyl)phthalate (OEHP)
74873
Methyl chloride (Chloromethane)
118741
Hexachlorobenzene
71556
Methyl chloroform (1,1,1-
Trichloroethane)
9
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TABLE 2. HAZARDOUS AIR POLLUTANTS !
CAS No. ORDER |
ALPHABETIC ORDER !
119904
D1methoxybenzidine(3,3-)
78933
1
Methyl ethyl ketone (2-Butanone)
119937
Dimethyl(3,3'-) benzidine
60344
Methyl hydrazine i
120809
Catechol
74884
Methyl iodide (Iodomethane)
120821
Trichlorobenzene(l,2,4-)
108101
Methyl isobutyl ketone (Hexone) '
121142
Dinitrotoluene(2,4-)
624839
Methyl isocyanate
121448
Triethylamine
1 80626
Methyl methacryl ate
121697
Diethyl(n,n-) aniline (n,n-
DimethylanilIne)
1634044
Methyl tert butyl ether
122667
Diphenylhydrazine(1,2-)
75092
Methylene chloride
(Dichloromethane)
123319
Hydroqulnone
101688
Methylene diphenyl d11socyanate
(MDI)
123386
Propionaldehyde
101144
Methylene(4,4-) bis(2-
chloroanlline)
123911
Dioxane(l,4-) (1,4-
Diethyleneoxide)
101779
Methylenedianll 1ne(4,4'-)
126998
Chloroprene
91203
Naphthalene
127184
Tetrachloroethylene
(Perchloroethylene)
Nickel compounds
131113
Dimethyl phthalate
98953
Nitrobenzene
132649
Dibenzofurans
92933
Nltroblphenyl(4-)
133062
Captan
100027
Nitrophenol(4-)
133904
Chloramben
1 79469
NitroproDane(2-)
140885
Ethyl acrylate
684935
N1troso(n-)-n-methylurea
151564
Ethylene imine (Azirldlne) i
1 62759
N1trosodimethylam1ne(n-)
156627
Calcium cyanamlde
59892
N1trosomorohol1ne(n-)
302012
Hydrazine
| 56382
Parathion
334883
Diazomethane
82688
Pentachloronltrobenzene
(Quintobenzene)
463581
Carbonyl sulfide
I 87865
Pentachlorophenol
510156
Chlorobenzilate
108952
Phenol
532274
Chioroacetophenone(2-)
1 106503
Phenylenedlamlne(p-)
534521
Dinitro(4,6-)-o-cresol, and salts
1 75445
Phosgene
540841
Tr1methylpentane(2,2,4-)
7803512
Phosphine
542756
Dichloropropene(l,3-)
7723140
Phosphorus
542881
Bis(chloromethyl)ether
1 85449
Phthal1c anhydride
10
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TABLE 2. HAZARDOUS AIR POLLUTANTS
CAS No. ORDER
ALPHABETIC ORDER
584849
Toluene(2,4-) dllsocyanate
1336363
Polychlorinated biphenyls
(Aroclors)
593602
Vinyl bromide
Polycyllc organic matter
624839
Methyl isocyanate
1120714
Propane(l,3-) sultone
680319
Hexamethylphosphorami de
57578
Propiolactone (beta-)
684935
Nitroso(n-)-n-methylurea
123386
Proplonaldehyde
822060
Hexamethylene-1,6-di i socyanate
114261
Propoxur (Baygon)
1120714
Propane(l,3-) sultone
78875
Propylene dlchlorlde (1,2-
Dlchloropropane)
1319773
Cresols/Cresylic acid (Isomers
and mixture)
75569
Propylene oxide
1330207
Xylenes (isomers and mixture)
75558
Propylen1mine(l,2-) (2-Methyl
azlridine)
1332214
Asbestos
91225
Quinol1ne
1336363
Polychlorinated biphenyls
(Aroclors)
106514
Qui none
1582098
Triflural in
Radionuclides (including radon)
1634044
Methyl tert butyl ether
Selenium compounds
1746016
Tetrachlorod1benzo(2,3,7,8-)-p-
dioxin
100425
Styrene
3547044
DDE
96093
Styrene oxide
7550450
Titanium tetrachloride
1746016
Tetrachlorodi benzo(2,3,7,8-)-p-
dioxin
7647010
Hydrochloric acid
79345
Tetrachloroethane(1,1,2,2-)
7664393
Hydrogen fluoride (Hydrofluoric
acid)
127184
Tetrachloroethylene
(Perchloroethylene)
7723140
Phosphorus
7550450
Titanium tetrachloride
7782505
Chlorine
108883
Toluene
7783064
Hydrogen sulfide
95807
Toluene(2,4-) diamine
7803512
Phosphine
584849
Toluene(2,4-) dllsocyanate
8001352
Toxaphene (chlorinated camphene)
95534
Toluldine(o-)
Antimony compounds
8001352
Toxaphene (chlorinated camphene
Arsenic compounds (Inorganic
Including arsine)
120821
Tr1chlorobenzene(l,2,4-
Beryllium compounds
79005
Tr1chloroethane(l,l,2-)
Cadmium compounds
79016
Trlchloroethylene
Chromium compounds
1 95954
Trichlorophenol(2,4,5-)
11
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TABLE 2. HAZARDOUS AIR POLLUTANTS
CAS No. ORDER |
ALPHABETIC ORDER
Cobalt compounds i
88062
Trlchlorophenol(2,4,6-)
Coke oven emissions
121448
Triethyl amine
Cyanide compounds
1582098
Trifluralin
Fine mineral fibers
540841
Tr1methylDentane(2,2,4-)
Glycol ethers
108054
Vinyl acetate
Lead compounds
593602
Vinyl bromide
Manqanese compounds
75014
Vinyl chloride
Mercury compounds
75354
Vinylldene chloride (1,1-
Dlchloroethylene)
Nickel compounds
1330207
Xylenes (Isomers and mixture)
Polycyllc organic matter
108383
Xylenes(m-)
Radionuclides (Including radon)
95476
Xylenes(o-)
Selenium compounds
106423
Xylenes(p-)
12
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C. Law of the Princeton University presented an overview of liquid
incineration phenomena and summarized Important parameters which impact the
performance of liquid-injection incinerators. The parameters discussed were:
droplets (20-2000 microns), sprays, and the blending of wastes with different
physical and chemical properties (CST90-pl).
V. McDonell of the University of California at Irvine described the
application of laser interferometry (optical scattering techniques) to the
study of droplet/gas-phase interaction and behavior in liquid spray combustion
systems. Three applications were presented: (1) the effect of swirl on the
dispersion of droplets; (2) an assessment of spray symmetry; and (3)
measurements 1n a reacting environment (CST90-p343).
Solids Combustion
G. Darivakis, et al., of MIT presented the pyrolysls and combustion behavior
of polyethylene (PE) and polystyrene (PS). In the first stage of solids
combustion, thermal decomposition transforms the starting material into two
products that fuel oxidation: a solid (char) and volatlles. The latter have
sufficient mobility and/or vapor pressure to separate from the decomposing
substrate. The detailed dynamics of this separation process
(devolatilization) determine the release rates, yields, compositions and
heating values of volatiles, and thus Impact ignition, flame duration,
heterogeneous versus homogeneous combustion Intensity, and emissions loadings,
compositions, and toxicity. This paper quantified basic features of PE and PS
devolatil1zat1on Including the yields of total volatiles (total weight loss)
and of condensibles (tars + higher molecular weight volatilizable material
that solidifies at room temperature). Measurements were performed at
temperatures and heating rates pertinent to solid waste incineration and to
fires (CST90-p267).
P. Lemieux, et al., of EPA discussed the effect of oxygen augmentation on
transient behavior 1n a rotary kiln. The study showed that physical processes
controlling the release of waste from the sorbent material are greatly
affected by the rotation speed of the kiln and the kiln temperature (CST90-
p311).
T. Lester, et al., of the Louisiana State University described the
repeatability of the transients resulting from the one-pack Insertion of
toluene/sorbent on the next insertion. Their study objective was to provide,
for the first time, detailed Information on the physical and chemical
environments inside the high temperature zones of an operating industrial
incinerator (CST90-p67).
J. Lighty, et al., of the University of Utah presented a study of transport
processes in a rotary kiln during the desorptlon of organic and metallic
contaminants from solids. As expected, lighter components desorb faster than
the heavier hydrocarbons (CST90-p31).
Metals Emissions
R. Barton, et al., of the Energy and Environmental Research Corporation
presented their computer model which can reportedly co-relate the trace metal
emission mechanisms of waste combustors. The mechanisms include particle
13
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entrainment, chemical speciation, chemical integrations, vaporization,
condensation, particle coagulation and particle collection by flue gas
cleaning equipment. The objective of the study was to assess the ability of
waste combustion devices to control the emission of toxic metals (CST90-p327).
R. Flagan, et al., of the California Institute of Technology discussed the
nature of pyrogeneous fumes (fumes formed due to heat). The paper indicated
that fume particles produced from, vapors 1n high temperature systems are
remarkably similar in structure, regardless of their composition or the
details of the system in which they were formed (ICTCB89-s9).
S. Friedlander, et al., of UCLA discussed the needs for better understanding
of aerosol formation, the chemistry of organic emissions, the processing of
solid and liquid incinerator feeds, the modelling and control of combustion
systems, gas mixing and turbulence and novel and advanced systems (ICTCB89-
s4). He and his coworkers also presented their work on the control of fine
aerosols 1n incineration processes (ICTCB89-S9).
N. Gallagher, et al., of the University of Arizona presented their work on the
alkali metal (sodium and potassium) partitioning from pulverized coal
combustion in a down-fired coal combustor. In all cases, sodium was enriched
in the small particle size range, and was shown to form both a sodium-rich
fume and an enriched surface layer around existing particles. (CST90-p211).
R. Quann, et al., of HIT presented their studies on the submicron particle
formation as a function of coal types 1n a laboratory combustion furnace.
When pulverized coal is burned, particles ranging in size from about 100
microns down into the submicron size may form and are composed primarily of
oxides (and sulfates) of Si, Al, Fe, Ca, Mg, K and Na. The submicron
particles, which may only comprise about 1 X of the total particle mass, are
of the greatest concern, because they are of respirable size, are surface-
enriched in toxic trace metals and are the least effectively captured by
conventional electrostatic precipitators (CST90-p245).
Organic Emissions
R. Barat, et al., of MIT and J. Bozzelli of the New Jersey Institute of
Technology (NJIT) presented their work In which they used a turbulent, jet-
stirred, toroidal combustor to study the inhibition of hydrocarbon oxidation
by chlorine. This work provided an understanding of how this inhibition leads
to flame instability and to PIC formation. The paper concluded that in the
presence of chlorine, blowout of the flame occurs sooner (I.e., at a lower
mass rate) after the onset of Instabilities than in a comparable combustion
environment without chlorine. The primary cause of this enhanced instability
was an inhibition of CO burnout due to the consumption of OH radicals by
product HC1. In addition, chain-terminating consumption of HO, radicals by Cl
further inhibited CO burnout since H02 was a major source of OH in their
testing system (CST90-p361).
H. Hagenmaler of the University of Tubingen in Germany presented the
mechanisms of formation and decomposition of polychlorlnated dibenzo-dioxin
(PCDD) and -furan (PCDF) in incineration processes. The mechanisms Include:
(1) PC DO/PCDF are already present in the waste and are incompletely destroyed
or transformed during combustion; (2) PCDO/PCDF are formed from structurally-
14
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related compounds such as PCBs, chlorobenzenes, etc.; and (3) PCDD/PCDF are
formed by de novo syntheses. This means that they are formed either from
organochlorlne compounds structurally not related to PCDD/PCDF such as
polyvinyl chloride (PVC) or by incomplete combustion of organic matter in the
presence of a chlorine source such as metal chlorides (ICTCB89-s8).
E. Ritter, et al., of NJIT discussed their work on the thermal reactions of
chloro- and dlchlorobenzene in H2 and chlorobenzene in H2/02 mixtures in a
tubular flow reactor between 835 and 1275*K. The study successfully
illustrated the elementary reaction pathways leading to the formation of
polychlorinated dibenzofurans (PCDFs) and dibenzodloxlns (PCDDs) by adding
oxygen atoms to a chlorinated biphenyl and a chlorinated dibenzofuran
respectively (CST90-pll7).
D. Tirey, et al., of the University of Dayton Research Institute (UDRI)
Introduced their work on the thermal degradation of tetrachloroethylene
(C2C1J and ethylene (C2HJ using a high-temperature flow reactor system. The
study showed that C2C14 has a propensity for formation of higher molecular
weight aromatic species that is similar to that of its non-chlor1nated
analogue, C,H4. Acetylene (C2H2) 1s the major product from C,H4 degradation
while hexacnlorobenzene (C6C16) is the major product from C2C1, decomposition
(CST90-pl37).
W. Tsang of the National Institute of Standards and Technology Introduced a
single-step reaction rate constant to aid 1n the understanding of the
formation and destruction of chlorinated organic compounds. However, he
warned that rechlorinatlon is possible 1n the post-combustion region, when the
surface temperature Is low (CST90-p99).
R. Van Dell of the Dow Chemical Company presented a simplified computer flame
model to predict the formation and destruction of soots and PICs 1n a
laboratory thermal oxidizer (LTOX). Although the simple model adequately
predicted flame temperature, diffusion velocity, soot yields and soot
concentrations, the author Indicated that refinement of the model was needed
(CST90-p379).
PAH and Soot Emissions
R. Barbel la, et al., of the University of Naples In Italy presented the
optical and chemical characterization of carbon polymorphs formed during the
spray combustion of hydrocarbons. Carbon polymorphs are a large variety of
carbon structures resulting from the spray combustion of mixed saturated,
unsaturated and aromatic hydrocarbons. The carbon polymorphs (which contain a
larger number of carbon atoms than those contained 1n the original fuel) could
represent toxic air pollutants since they Include compounds such as
substituted and unsubstltuted polycyclic aromatic compounds (PACs) and larger
aggregates of carbon atoms such as tar and soot (CST90-pl59).
M. Frenklach of Pennsylvania State University presented his study on the
formation of polycyclic aromatic hydrocarbons (PAHs) 1n chlorine-containing
environments. PAHs are the precursors of soot and have been Identified as
carcinogenic and mutagenic. His study which showed that the presence of
chlorine in hydrocarbon systems strongly promotes the formation of PAHs has
concluded that: (1) the enhanced, chlorine-catalyzed degradation of POHC
15
-------
molecules promotes the formation of aromatic ring compounds; and (2) the large
concentration of CI atoms accelerates the abstraction of aromatic H from
stable PAH molecules, and activates them for further growth (CST90-p283).
J. McKinnon, et al., of MIT presented the soot formation mechanisms and the
effects of chlorine. Chlorine 1s a known Inhibitor of combustion and promoter
of soot formation. The paper concluded that soot formation involves the
growth of high molecular weight PAHs, the reactive coagulation of these heavy
molecules, and mass addition from PAH and acetylene. These processes are
opposed by oxidative and pyrolytlc degradation, thus resulting In a
competition which determines whether and to what extent any soot emission
occurs (CST90-pl75).
J. Mitchell, et al., of the University of Western Ontario presented the
results of using additives to control soot formation. Additives can either
enhance soot oxidation or Inhibit soot agglomeration so that the soot
particles remain small and thus are easily oxidized (CST90-p63).
Acid Gas Emissions
M. Ravichandran, et al., of Cornell University discussed the chemical kinetic
constraints placed on N0X reduction by aranonia Injection 1n both a perfectly
stirred reactor and a plug flow reactor. The results indicated that N0X
reduction by ammonia injection 1n the case of incinerators would require more
stringent process control and 1s likely to require higher amounts of NH3 and
H2 to achieve NO reduction efficiencies comparable to what has been achieved
in the case of utility boiler furnaces. One of reasons for this 1s that waste
incinerators use more excess air than that of utility boilers (ICTCB89-s10).
Simulations and Transport
G. Si 1 cox, et al., of the University of Utah presented their study on the
mathematical and physical modeling of rotary kilns with applications to
scaling and design. The model study examined heat and mass transfer in an
indirectly-fired rotary kiln, and mixing times 1n a slumping kiln bed. The
design and operating study examined k11n length, solids residence time, solids
feed rate, and feed moisture content. The effects of moisture were
particularly important to both heat and mass transfer (ICTCB89-S10).
P. Smith, et al., of Brigham Young University presented their application of
computational combustion simulations to full-scale pulverlzed-coal Industrial
furnaces and utility boilers. Heterogeneous and turbulent heat transfer
aspects strongly Influence the formation and decay of byproducts In practical
coal combustion systems because many of the sub-processes resulting in
combustion byproducts are highly temperature-sensitive and because the purpose
of most furnaces 1s to extract energy from the flame (1CTCB89-S10).
TCB Control
T. Brna of the U.S. EPA presented an overview of TCB control options which
included: (1) in-furnace methods; and (2) post-combustion methods (CST90-
p83).
16
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M. Ho, of Union Carbide Industrial Gases, Inc. presented the method of oxygen
enrichment to control the transient emissions from a rotary kiln; the method
described was an In-furnace method (ICTCB89-s7).
J. Kllgroe, et al., of the U.S. EPA described the use of combustion control
for limiting organic emissions (mainly chlorinated dibenzo-p-d1oxins and
-furans) from municipal waste combustors. The paper defined the concept of
"good combustion practices (GCP)" as the set of conditions that minimize the
emission of organic compounds. GCPs at that time included: (1) uniformity of
waste feed; (2) adequate combustion temperature; (3) amount and distribution
of combustion air; (4) mixing; (5) minimization of particulate matter
carryover; (6) control of downstream temperature; and (7) combustion
monitoring and control (CST90-p223).
R. Wood, et al., of the ASME Research Committee on Industrial and Municipal
Waste presented methods to minimize combustion excursions from rotary kiln
incinerators. The paper found that an operating kiln produces no significant
combustion excursions from batch feeds when the minimum oxygen level at the
outlet of the combustor 1s above 1% (ICTCB89-s7).
Monitoring. Sampling and Analysis
W. McClennen, et al., of the University of Utah presented a system for the on-
line analysis of organic vapors by short-column (1 meter) gas
chromatography/mass spectrometry (GC/MS) to monitor products from a thermal
soil desorptlon reactor. The broad range of boiling points and polarities of
the organic compounds in wastes mandates the use of sophisticated
instrumentation for monitoring their production, evolution, and destruction.
The short-column GC/MS can accurately measure the transient concentrations
(30-60 second intervals) of a broad range of aromatic compounds. It can
separate the organic vapors away from the major ambient atmospheric
constituents and also provide some separation of isomers otherwise
indistinguishable by MS. The mass spectrometer provides a rapid and sensitive
method of compound identification (CST90-p297).
Risk Assessment
In the past, EPA's incineration standards such as the Destruction and Removal
Efficiency (DRE), HC1 and particulate requirements have been technology-based
standards. The BIF rule Incorporates risk assessment calculations into the
requirements of the standard.
A. Smith, et al., of The Unlverlsty of California at Berkeley discussed the
health risk assessment of Incinerator air emissions Incorporating background
ambient air data. The emissions data used were supplied by Ogden Martin
Systems, Inc. and were derived from stack sampling at a municipal waste
Incinerator located at West Babylon on Long Island, New York. Key compounds
used for the risk assessment were PCDOs, PCDFs, lead and mercury. Human
exposure was estimated for a lifetime average exposure of a hypothetical
person living for 70 years, 24 hours per day, at the point of maximum annual
average ground level concentration of emissions. The study concluded that the
cancer risks attributable to air pollution emissions from a municipal waste
Incineration facility with modern air pollution equipment are below 1 in
100,000. (CST90-p51).
17
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WHAT HAVE WE LEARNED FROM THE ICTCB?
"A lot" is probably the most simple way to describe what we have learned from
the information presented at the First ICTCB. The thirteen areas identified
in the above-mentioned groups/sutrcnary are but a sampling. Each area has so
much more information to offer. Using the area of metals emissions as an
example, metals speciation research requires specialized knowledge to fully
understand the mechanisms that Influence which metals species goes to which
effluent stream when metals are 1n the incineration/combustion environments.
WHAT CAN WE USE FROM WHAT WE HAVE LEARNED?
The technical community has been searching for answers to the following
questions:
(1) Are significant TCBs actually being emitted from waste
incinerators from an environmental risk standpoint and how much,
quantitatively and qualitatively?
(2) Why is the Issue of TCBs still the focus of the public's concern,
after so many years of research and after so many risk assessments
have shown TCBs to be relatively benign (as long as appropriate
pollution controls are Incorporated Into the Incinerator design)?
(3) Do other treatment technologies emit any unwanted reaction by-
products (RBPs) and how much?
(4) Is there any comparison between TCBs and RBPs? which are more
harmful to human health and the environment?
(5) Can scientists provide any data to relieve the public's fears or
to overcome their "NIMBY" attitude?
Perhaps the ICTCBs may be able to provide answers to the above questions.
WHAT IMPROVEMENT IS NEEDED?
Based upon the research topics/areas reviewed herein, the authors believe that
the ICTCBs of the future need to emphasize such additional topics as:
• Performance assurance (to assure that a permitted system will
perform to the degree required);
• Ash quality and Its reuse or Its ultimate disposal;
• The ultimate disposal of spent wastewaters from any air pollution
control operations associated with Incineration/combustion;
• Fugitive emissions;
• The public's involvement; and
• Health effects from environmental contaminations (this subject was
Included 1n the Second and Third ICTBPs).
The authors anxiously await the Fourth Congress — see you at Cal-BerkeleyI
18
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REFERENCES
(CST90-pxx), Papers Presented at the 1989 International Congress on Toxic
Combustion Byproducts, University of California at Los Angeles, California,
August 2-4, 1989 and Published in the Combustion Science Technology (CST),
Volumes 74, Number 1-6, 1990, Page xx.
(Del 1 inger-4/90), "PIC Formation - Research Status and Control Implications,1'
B. Dellinger, P. H. Taylor, and C. C. Lee. Presented at the 16th EPA Annual
Meeting, Cincinnati, Ohio, April 3-5, 1990.
(ICTCB89-sxx), Abstract Proceedings of the 1989 International Congress on
Toxic Combustion Byproducts, University of California at Los Angeles,
California, August 2-4, 1989, Session xx.
(Lee-7/88), "A Model Analysis of Metal Partitioning in a Hazardous Waste
Incineration System," C. C. Lee, JAPCA, July 1988.
(Lee-8/88), "Incineration of Solid Waste," C. C. Lee, and G. L. Huffman.
Presented at the 1988 AIChE Annual Meeting and 80th Anniversary Commemoration,
Washington, DC, November 27-December 2,1988 and Published In the Journal of
Environmental Progress, August 1989.
(Lee-4/90), "Incinerability Ranking Systems for RCRA Hazardous Constituents,"
C. C. Lee, G. L. Huffman and S. M. Sasseville, Hazardous Waste & Hazardous
Materials, Volume 7, Number 4, April 1990.
(Lee-5/90), "Thermodynamic Fundamentals Used in Hazardous Waste Incineration,"
C. C. Lee and G. L. Huffman. Presented at the 1990 Incineration Conference,
San Diego, California, May 14-18, 1990.
(Lee-11/90), "Regulatory Framework for Combustion By-Products from
Incineration Sources," C.C. Lee and G.L. Huffman. Presented at the 1990
Pacific Basin Conference on Hazardous Waste, Honolulu, Hawaii, November 12-16,
1990.
(Lee-2/91), "Minimization of Combustion Byroducts: Characteristics of
Hazardous Waste," C. C. Lee and G. L. Huffman. Presented at the National
Research and Development Conference on the Control of Hazardous Materials held
in Anaheim, California on February 20-22, 1991.
(Lee-4/91), "Environmental Law Relating to Medical Waste in the United States
of America," C. C. Lee, and G. L. Huffman, The Journal of the International
Solid Wastes and Public Cleansing Association (ISWA), Volume 9, Number 2,
April 1991.
(Lee-8/91), "Metals Behavior During Medical Waste Incineration," C. C. Lee and
G. L. Huffman. Presented at the National Meeting of the American Chemical
Society, New York, August 26-30, 1991.
19
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TECHNICAL REPORT DATA
(Please rtati Instructions on the reverse before comf
¦
1. REPORT NO. 2.
EPA/600/A-94/225
4. title and subtitle
Minimization of Toxic Combustion Byproducts: Review
of Current Activities
5 REPORT OATE
September 7. 1993
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
C.C. Lee and G.L. Huffman
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME ANO AOORESS
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
10. PROGRAM ELEMENT NO.
NA
11. CONTRACT/GRANT NO.
NA
12. SPONSORING AGENCY NAME ANO AOORESS
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, OH 45268
13. TYPE OF REPORT ANO PERIOD COVERED
Tn-house: Julv-Auaust 1993
14. SPONSORING AGENCY COOE
EPA/600/14
10. SUPPLEMENTARY NOTES
Any comments or questions, contact EPA's Dr. C.C. Lee on 513/569-7520.
Presented at the 1993 Pacific Basin Conference on Hazardous Waste,Nov <1993;pg 1-19
is.abstract jn generai> toxic combustion byproducts (TCBs) are the unwanted residues
remaining in flue gases, combustion ashes, and wastewaters from the operation
of an incineration or combustion facility. If a combustor is not well
designed and operated, it may emit too high a level of TCBs.
The issue of TCBs has been one of the major technical and sociological
issues surrounding the implementation of incineration as a waste treatment
alternative. Because of the complexity and controversy, EPA's Dr. C.C. Lee in
1989 conceived of and initiated the International Congress on Toxic Combustion
Byproducts (ICTCB) to provide a forum for scientists to discuss the issues of
and controls for TCBs.
This Paper focuses on the review of the 1989 ICTCB (the First ICTCB)
activities. The 1991 (the Second) and 1993 (the Third) ICTCB activities will
be reviewed at another time. The objective of these reviews is to discuss:
(1) What have we learned from the ICTCB conferences;
(2) What can we use from what we have learned; and
(3) What improvement in the ICTCBs 1s needed.
17. KEY WORDS ANO DOCUMENT ANALYSIS
a. DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. cosati Field/Group
Incineration, hazardous waste
combustion, products of Incomplete
combustion, metals emissions
IS. DISTRIBUTION STATEMENT
RELEASE TO THE PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
21
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (Rav. 4-77) previou* edition is obsolete
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