United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/S2-86/096 Feb. 1987
<>EPA Project Summary
Technical Resource
Document: Treatment
Technologies for
Dioxin-Containing Wastes
Marc Breton, Mark Arienti, Paul Frillici, Michael Kravett, Steven Palmer,
Andrew Shayer, and Norman Surprenant
The 1984 Hazardous and Solid Waste
Act Amendments to the Resource Con-
servation and Recovery Act (RCRA) di-
rected EPA to ban certain dioxin-
containing wastes from land disposal
unless EPA determines that restrictions
on land disposal of these wastes are
not needed to protect human health
and the environment. Congress,
through the 1984 Amendments, fixed a
deadline of 24 months from the enact-
ment of the Amendments for EPA to
regulate the land disposal of these iden-
tified wastes (with some exceptions). In
the event that the Agency has not is-
sued regulations by that time (Novem-
ber 1986), land disposal of all specified
dioxin-containing waste streams auto-
matically will be banned.
An important aspect of the land dis-
posal restrictions is the identification
and evaluation of alternative technolo-
gies that can be used to treat the listed
wastes in such a way as to meet pro-
posed treatment levels which EPA has
determined are protective of human
health and the environment. If alterna-
tives to land disposal are not available
by November 1986, it may be necessary
to extend the deadline for the restric-
tions on land disposal. The full report
identifies and evaluates alternative
technologies that remove and/or de-
stroy dioxin and related compounds
from listed dioxin wastes in order to
achieve constituent levels that allow
the safe land disposal of the treated
residues.
This Project Summary was devel-
oped by EPA's Hazardous Waste Engi-
neering Research Laboratory, Cincin-
nati, OH, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Scope
A number of potential technologies
exist for treating wastes containing
dioxin. Because many of the technolo-
gies are currently in developmental
stages, it is not possible to assess fully
the effectiveness of these technologies
at this time. Further testing of a technol-
ogy in the future may, for example, indi-
cate that a technology is or is not practi-
cal on a full scale. In addition, several
new technologies for treating dioxin
wastes may emerge for which informa-
tion is not currently available. Conse-
quently, it must be emphasized that the
information discussed here represents
that which was available in the spring of
1986.
Technologies under evaluation are
those that destroy dioxin or somehow
change its form so that it is less toxic.
Temporary management methods,
such as storage in mines, are not evalu-
ated because these methods only
involve moving the waste without
changing the chemical form and charac-
teristics of the waste. The majority of
the technologies are those whose per-
formance has been tested on dioxin-
-------
containing wastes. Those that have not
been tested on dioxin-containing
wastes have, at least, been tested on
PCB-containing wastes. Because of the
similarity of PCBs and dioxins, these
technologies should also be applicable
to dioxin wastes. Technologies that
have been developed to full scale as
well as those only investigated in the
laboratory are included. This is primar-
ily because, as mentioned previously,
this field is rapidly evolving. Many of
the technologies that are now only in
the laboratory stage may be standard
technologies for treatment of these
wastes in the future.
Definition of Dioxin Waste
The term "dioxin waste" is meant to
include those RCRA wastes listed as
EPA hazardous waste Numbers F021,
F022, F023, F026 and F027. As shown in
Table 1, these waste codes are desig-
nated as "acute hazardous" and include
wastes from the production and manu-
facturing use of tri-, tetra-, and pen-
tachlorophenols, wastes from the man-
ufacturing use of tetra-, penta-, and
hexachlorobenzene under alkaline con-
ditions, and also discarded, unused for-
mulations containing tri-, tetra-, and
pentachlorophenols. Soil that has been
contaminated by improper manage-
ment of these wastes is also encom-
passed by these waste codes. Residue;;
from the incineration of this contami-
nated soil are designated as toxic in-
stead of acute hazardous and are cov-
ered under waste code F028.
The wastes described by these waste
codes are listed hazardous wastes pri-
marily because they contain one of a
number of forms of dioxin. The term
"dioxin" has been used very loosely. It
encompasses a family of aromatic com
pounds known chemically as dibenzo-p
dioxin. The forms of dioxin that are of
most environmental concern are the
chlorinated dioxins, in which a chlorine
atom occupies one or more of the avail
able eight positions on the double ben
zene ring structure. Thus, there are 7Ei
possible chlorinated dioxin com
pounds, the most toxic of which is
2,3,7,8-tetrachlorodibenzo-p-dioxin
(TCDD). Throughout the full report, vari
ous terms will be used to refer to certain
types of dioxin. When only the word
"dioxin" is used, it refers to chlorinated
dioxin compounds in general. Other
commonly used abbreviations are:
PCDDs =all isomers of chlori-
nated dibenzo-p-
dioxins
Table 1.
EPA
hazardous
waste no.
Dioxin Contaminated Wastes Listed as RCRA Hazardous Wastes, January 14 1985
50 FR 1978
Hazardous Waste From Nonspecific Source
Hazardous waste
Hazard
code
Wastes** from the production or manufacturing use of tri- (H)
or tetrachlorophenol, or of intermediates used to produce
their derivatives. **
Wastes** from the production or manufacturing use of (H)
pentachlorophenol (POP), or of intermediates used to pro-
duce its derivatives.
Wastes** from the manufacturing use of tetra-, penta-, or (H)
hexachlorobenzene under alkaline conditions.
Wastes** from the production of materials on equipment (H)
previously used for the production or manufacturing use
of tri- or tetrachlorophenols.***
Wastes** from the production of materials on equipment (H)
previously used for the manufacturing of tetra-, penta , or
hexachlorobenzene under alkaline conditions. *
Discarded unused formulations containing tri-, tetra-, or (H)
pentachlorophenol or discarded unused formulations
derived from these chlorophenols.****
Residues resulting from the incineration or thermal treat- (T)
ment of soil contaminated with EPA hazardous waste F020,
F021, F022, F023, F026, and F027.
*A proposed regulation [50 FR 37338] would make residues from the incineration of these
wastes (if the waste contained less than or equal to 10 ppm TCDD prior to incineration)
toxic instead of acute hazardous.
**Except wastewater and spent carbon from hydrogen chloride purification.
***This listing does not include wastes from the production of hexachlorophene from highly
purified 2,4,5-trichlorophenol.
****This listing does not include formulations containing hexachlorophene synthesized from
prepurified 2,4,5-trichlorophenol as the sole component.
(H) = Acute Hazardous Waste
(T) = Toxic Waste
F020*
F02V
F022*
F023*
F026*
F027*
F028
CDDs =all isomers of tetra-,
penta-, and
hexachlorodibenzo-p-
dioxins
TCDD , = the 2,3,7,8- isomer
PeCDD, I
HxCDD, r = the penta-, hexa-, and
and OCDDJ octachloro compounds
Other toxic constituents that may be
present in the listed dioxin wastes are
chlorinated dibenzofurans (CDFs),
chlorophenols, and chlorophenoxy
compounds.
Waste Sources, Characteristics,
and Quantities
The waste codes included in the
dioxin listing encompass process
wastes from the production of various
chlorophenols, primarily 2,4,5-
trichlorophenol and pentachlorophe-
nol, and chlorophenoxy pesticides such
as 2,4,5-T and Silvex. As indicated in a
report prepared by Technical Re-
sources, Inc. for the EPA Office of Solid
Waste, the manufacture of most of
these compounds has been stopped.
For example, 2,4,5-trichlorophenol has
not been manufactured for several
years. As a result, the majority of the
dioxin-bearing process wastes requir-
ing treatment at this time are wastes
such as still bottoms and reactor
residues that were generated in the past
and remain to be treated. The only proc-
ess waste stream that is still being
generated, and may continue to be gen-
erated in the future, is from the manu-
facture of pentachlorophenol (PCP).
However, by far the largest quantity of
dioxin-bearing wastes that have been
identified are the contaminated soils
-------
such as those at Times Beach, Missouri,
and various other CERCLA sites
throughout the country.
Table 2 shows estimated waste quan-
tities for each of the waste codes. Sev-
eral items associated with the informa-
tion in the table should be noted. One is
that no sources have yet been identified
for waste codes F022 and F026. Another
is that waste code F028 is not included
because it is expected that residues
from future incineration of contami-
nated soil will meet EPA delisting re-
quirements. Finally, contaminated soils
are placed in a separate category both
because of their unique physical form
relative to most process wastes, and
also because a large fraction of the con-
taminated soils are at CERCLA sites
whose wastes will not be affected by the
RCRA land disposal restrictions until
November 1988.
The estimates of the quantities of
wastes generated within each waste
category in Table 2 could have a signifi-
cant impact on future treatment prac-
tices. As shown in the table, there are
more than 500,000 metric tons of
dioxin-contaminated soil that may re-
quire treatment. This quantity is consid-
erably greater than the estimated maxi-
mum 7500 MT of process wastes, such
as still bottoms currently requiring
treatment and the estimated 2500 MT of
industrial process wastes that will be
generated in future years. Conse-
quently, it would appear that treatment
technologies capable of treating soil
wastes are of most importance at this
time, particularly those technologies,
such as solvent extraction, that are ca-
pable of removing the toxic con-
stituents from the soil and thereby re-
ducing the total volume of waste
requiring final detoxification/destruc-
tion.
Technologies for Treating
Dioxin Wastes
As mentioned previously, a number
of technologies for treating dioxin
waste are evaluated in this document. A
summary of the status of these tech-
nologies is provided in Table 3. Because
studies have shown that dioxin decom-
poses by heating or oxidation at tem-
Table 2. Summary of Dioxin Waste Sources and Quantities
Quantity generated
(metric tons)
Waste
code
Waste source
Physical form
Present
(or stored)
Future
n
F020 Manufacture of herbicides such as
2,4,5-T, 2,4,5-trichlorophenol, hex-
achlorophene; disposal of wastes
in uncontrolled landfills or stor-
age areas
F021 Manufacture of pentachlorophe-
nol: wastes from purification;
wastes from formulation
F022 No known sources at this time
F023 Production of chemicals on equip-
ment formerly used to manufac-
ture F020 compounds, e.g., 2,4-D
on 2,4,5-T equipment
F026 No known sources at this time
F027 Discarded formulation of in-,
tetra-, and pentachlorophenols
and their derivatives
Contaminated soil from improper
disposal and spills of F020-F027**
*NA-Not applicable.
**Not listed as a specific waste code.
**Only from pentachlorophenol products.
Still bottoms containing or-
ganic solvents and chloro-
phenols
- Nonaqueous phase leachate
(NAPL) containing solvents,
chlorophenols, heavy metals
- Carbon used to treat aqueous
leachate
- Still bottoms or other con-
centrated materials contain-
ing nonvolatile organic solids
and chlorinated solvents and
phenols
- Sludges from formulation
- NA*
- Similar to F020 wastes - still
bottoms, reactor residues
containing chlorophenols and
organic solvents, and wash
water sludges from formula-
tion
- NA
- Active ingredient in an emul-
sifiable concentrate, as a salt
or an ester, or dissolved in
an oil (such as in the case of
pentachlorophenol)
- Soils containing low concen-
trations of dioxins and re-
lated compounds
NAPL -1,450
Other - 550
0-200
Unknown
Still bottoms-0
Formulation waste-
700
0
0-600
750
Unknown
0
0-600
1000-2000
500,000
0-1,000**'
Unknown
-------
Table 3. Summary of Treatment Processes
Applicable
Process name waste streams
Stationary Rotary Solids, liquids, sludges
Kiln Incineration
Mobile Rotary Kiln Solids, liquids, sludges
Incineration
Liquid Injection In- Liquids or sludges with
cineration viscosity less than
10,000 ssu
(i.e., pumpable)
Fluidized-bed In- Solids, sludges
cineration (Circu-
lating Bed Com-
bustor)
High Temperature Primarily for granular con-
Fluid Wall (Huber taminated soils, but may
AER) also handle liquids
Stage of Performance/
development destruction achieved Cost
Several approved Greater than six nines ORE $0.25-$0.70/lb for
and commercially for PCBs; greater than five PCB solids
available units for nines ORE demonstrated
PCBs; not yet on dioxin at combustion
used for dioxins research facility
EPA mobile unit Greater than six nines ORE NA*
is permitted to lor dioxin by EPA unit;
treat dioxin process residuals delisted
wastes; ENSCO
unit has been
demonstrated on
PCB waste
Full scale land- Greater than six nines ORE $200-$500/ton
based units per- on PCB wastes; ocean in-
mitted for PCBs; cinerators only demon-
only ocean incin- strated three nines on
erators have han- dioxin containing herbi-
dled dioxin cide orange
wastes
GA Technologies Greater than six nines ORE $60-$320/ton for
mobile circulating demonstrated by GA unit GA unit
bed combustor on PCBs
has a TSCA per-
mit to burn PCBs
anywhere in the
nation; not tested
yet on dioxin
Huber stationary Pilot scale mobile unit $300-$600/ton
unit is permitted demonstrated greater than
to do research on five nines ORE on TCDD -
dioxin wastes; contaminated soil at
pilot scale mobile Times Beach (79 ppb re-
reactor has been duced to below detection)
tested at several
locations on
dioxin contami-
nated soils
Residuals
generated
Treated waste material
(ash), scrubber waste-
water, paniculate from
air filters, gaseous
products of combus-
tion
Same as above.
Same as above, but
ash is usually minor
because solid feeds
are not treated
Treated waste (ash),
particulates from air
filters
Treated waste solids
(converted to glass
beads), particulates
from baghouse,
gaseous effluent (pri-
marily nitrogen)
Infrared Incinerator Contaminated soils/sludges Pilot scale,
(Shirco) portable unit
tested on waste
containing
dioxin; full scale
units have been
used in other ap-
plications; not
yet permitted for
TCDD
Greater than six nines ORE
on TCDD-contaminated
soil
Treatment costs
are $200-$ 1,200
per ton
Treated material (ash)
particulates captured
by scrubber (sepa-
rated from scrubber
water)
Molten Salt (Rock-
well Unit)
Solids, liquids, sludges;
high ash content wastes
may be troublesome
Pilot scale unit
was tested on
various wastes-
further develop-
ment is not
known
Up to eleven nines ORE on
hexachlorobenzene;
greater than six nines ORE
on PCB using bench scale
reactor
NA
Spent molten salt cor
taining ash, particu-
lates from baghouse
-------
Table 3. (continued)
Applicable
Process name waste streams
Supercritical Water
Oxidation
Plasms Arc Pyroly-
sis
In Situ Vitrification
Solvent Extraction
Stabilization/Fixa-
tion
UV Photolysis
Chemical
Dechlorination-
APEG processes
Aqueous solutions or slur-
ries with less than 20 per-
cent organics can be
handled
Liquid waste streams (pos-
sibly low viscosity sludges)
Contaminated soil - soil
type is not expected to af-
fect the process
Soils, still bottoms
Contaminated soil
Liquids, still bottoms, and
soils can be treated if
dioxin is first extracted or
desorbed into liquid
Contaminated soil (other
variations of the process
used to treat PCB-contami
nated soils)
Stage of
development
Pilot scale unit
tested on dioxin-
containing
wastes- results
not yet published
Prototype unit
(same as full
scale) currently
being field tested
Full scale on ra-
dioactive waste;
pilot scale on or-
ganic contami-
nated wastes
Full scale still
bottoms extrac-
tion has been
tested-pilot scale
soils washer
needs further in-
vestigation
Laboratory scale
using cement and
emulsified as-
phalt; lab tests
also using K-20
Full scale solvent
extraction/UV
process was used
to treat 4,300 gal-
lons of still bot-
toms in 1980;
thermal desorp-
tion/UV process
currently under-
going second
field test
Slurry process
currently being
field tested at
pilot scale; in situ
process has been
tested in the field
Performance/
destruction achieved
Six nines ORE on dioxin-
containing waste reported
by developer, but not pre-
sented in literature; lab
testing showed greater
than 99.99% conversion of
organic chloride for
wastes containing PCB
Greater than six nines de-
struction of PCBs and CCI4
Greater than 99.9% de-
struction efficiency (DE)
(not offgas treatment sys-
tem) on PCB-contaminated
soil
Still bottom extraction:
340 ppm TCDD reduced to
0.2 ppm; 60-90% removal
from soils, but reduction
to below 7 ppb not
achieved
Tests using cement
showed decreased leach-
ing of TCDD, but up to
27% loss of stabilized ma-
terial due to weathering
followed by leaching
Greater than 98.7% reduc-
tion of TCDD using solvent
extraction/UV process-
residuals contained ppm
concentrations of TCDD;
thermal desorption/UV
process demonstrated re-
duction of TCDD in soil to
below 7 ppb
Laboratory research has
demonstrated reduction of
2,000 ppb TCDD to below
7 ppb for slurry (batch
process); laboratory and
field testing of in situ
process not as promising
Cost
$0.32-$2.00/gal-
lon
$77-$480/ton
$300-$1,400/ton
$120-$250/m3
NA
NA
Cost of treating
the 4,300 gallons
of still bottoms
using solvent ex-
traction/UV was
$1 million; ther-
mal desorption/
UV estimated to
cost $250-$!, 250/
ton
$296/ton for in
situ APEG proc-
ess; $91 /ton for
slurry (batch)
process
Residuals
generated
High purity water, in-
organic salts, carbon
dioxide, nitrogen
Exhaust gases (H2 and
CO) which are flared
and scrubber water
containing particulates
Stable/immobile
molten glass; volatile
organic combustion
products (collected
and treated)
Treated waste mate-
rial (soil, organic liq-
uid); solvent extract
with concentrated
TCDD
Stabilized matrix (soil
plus cement, asphalt.
or other stabilization
material); matrix will
still contain TCDD
Solvent extraction/UV
process generated
treated still bottoms, a
solvent extract stream.
and an aqueous salt
stream; thermal des-
orption/UV generates
a treated soil stream
and a solvent extract
stream
Treated soil contain-
ing chloride salts
(reagent is recovered
in the slurry process)
-------
Table 3. (continued)
Process name
Applicable
waste streams
Stage of
development
Performance/
destruction achieved Cost
Residuals
generated
Biological
Degradation-
primarily in situ
addition of mi-
crobes
Chemical Degrada-
tion using Ruthe-
nium Tetroxide
Chemical Degrada-
tion using
Chloroiodides
Research has been di-
rected toward in situ treat-
ment of contaminated
soils-liquids are also pos-
sible
Liquid or soil wastes-pos-
sible most effective in de-
contaminating furniture
other surfaces
Liquid or soil-thought to
be most applicable to de-
contaminating furniture
and buildings
Currently labora- 50-60% metabolism of
tory scale-field
testing in next
year or two
Laboratory scale-
no work reported
since 1983
Laboratory scale-
no work reported
since 1983
2,3,7,8-TCDD in a week
long period under lab con-
ditions using white rot
fungus-reduction to
below 1 ppb not achieved
Reduction of 70 ppb TCDD
to below 10 ppb in 1 hr
(on soil sample)
Up to 92% degradation on
solution of TCDD in ben-
zene-reductions to below
1 ppb were not demon-
strated
NA Treated waste
medium such as soil
or water with TCDD
metabolites depend-
ing on microorgan-
isms
NA Treated medium plus
the solvent which has
been added (water,
CCI4); TCDD end prod-
ucts not known
NA Treated waste
medium; degradation
end products are
chlorophenols
Gamma Ray Radi-
olysis
Liquid waste streams (has
been applied to sewage
sludge disinfection)
Laboratory re-
search; no re-
search currently
being conducted
97% destruction of 2,3,7,8-
TCDD in ethanol after 30
hours- 100 ppb to 3 ppb
Cost for sewage
disinfection facil-
ity treating 4 tons
per day is $40 per
ton; TCDD treat-
ment would be
more expensive
Less chlorinated
dioxin molecules are
the degradation end
products in addition to
the treated waste
medium
*Not available
peratures greater than 1000°C, thermal
methods for treating these wastes have
received a large amount of attention.
Thermal technologies evaluated in this
document are those in which heat is the
major agent of treatment or destruction.
Technologies included in this category
are:
• Stationary rotary kiln incineration
• Mobile rotary kiln incineration
• Liquid injection incineration
• Fluidized-bed incineration
• Infrared incineration
• High temperature fluid wall de-
struction
• Plasma arc pyrolysis
• Molten salt destruction
• In-situ vitrification
• Supercritical water oxidation
EPA has indicated that incineration is
currently the only sufficiently demon-
strated treatment technology for dioxin-
containing waste (51 FR 1733). RCRA
performance standards for incineration
and other thermal treatment processes
require the demonstration of 99.9999
percent destruction and removal effi-
ciency (DRE) of the principal organic
hazardous constituent (POHC). Several
of the thermal technologies have
demonstrated this performance on
chlorinated compounds of one type or
another. However, only three, and per-
haps four, thermal technologies have
been demonstrated to achieve this level
of performance on dioxin. These tech-
nologies are the EPA mobile rotary kiln
incinerator, Huber's high temperature
fluid wall reactor, Shirco's infrared in-
cinerator, and possibly, Modar's super-
critical water oxidation process. Modar
has not yet released data conclusively
showing six nines DRE, but they do
claim to have achieved this perform-
ance. Thermal technologies that have
achieved six nines DRE on PCBs include
stationary rotary kiln incinerators, liquid
injection incinerators, fluidized-bed in-
cinerators (the circulating bed varia-
tion), the plasma arc process, and the
molten salt process. The in situ vitrifica-
tion process has not shown six nines
DRE; however, it is as much a stabiliza-
tion process as it is a destruction proc-
ess. Therefore, the primary objective of
this technology is to prevent the leach-
ing of dioxin or other toxic constituents
from the treated soil; whether the
dioxin is driven out of the soil by
volatilization or merely contained
within the vitrified material is a second-
ary concern (as long as volatilized
dioxin is captured and subsequently de-
stroyed).
Nonthermal technologies evaluated
include the following:
• Chemical dechlorination
• Ultraviolet (UV) photolysis
• Solvent extraction
• Biodegradation
• Stabilization/fixation
• Chemical degradation using ruthe-
nium tetroxide
• Chemical degradation using chlo-
roiodides
• Gamma ray radiolysis
Of the nonthermal technologies,
those that have shown the most
promise and the highest level of recent
investigation and testing are chemical
dechlorination and UV photolysis. Both
of these technologies are currently be-
ing field tested on dioxin-contaminated
soil. As indicated in Table 3, preliminary
field data on the thermal desorption/UV
photolysis process indicate that dioxin
was desorbed from soil to a level below
1 ppb, and then destroyed efficiently
using ultraviolet radiation. The chemi-
cal dechlorination process has also
-------
demonstrated a reduction of TCDD in
soil to below 1 ppb, but only on a labo-
ratory scale.
The other nonthermal processes have
not shown as much promise with re-
gard to treating dioxin waste. Solvent
extraction is a potentially useful tech-
nology since it could, if successfully ap-
plied to soil treatment, reduce the vol-
ume of the waste stream that requires
final treatment/destruction by several
orders of magnitude. Unfortunately,
this technology has not yet demon-
strated the ability to reduce dioxin in
contaminated soil to a level of 1 ppb.
Biodegradation is also a potentially at-
tractive approach since it presumably
would not require the large energy in-
puts, sophisticated equipment, and the
chemical additions that the other tech-
nologies require. However, biodegrada-
tion, particularly in situ, has not proven
to be very effective as a dioxin destruc-
tion process. Stabilization and/or fixa-
tion would allow the treatment of con-
taminated soils in place. Since this
method does not involve destruction of
the dioxin there is always the possibility
that the stabilized waste/soil matrix will
break down and the dioxin will be re-
leased. Finally, the last three technolo-
gies listed (two chemical degradation
processes and gamma ray radiolysis)
are methods that have been studied in
the laboratory but have not yet shown
enough promise technically or econom-
ically to be developed on a larger scale.
Investigation of these methods, at this
time, appears to have stopped.
Of all the treatment technologies
evaluated none is currently commer-
cially available for the treatment of
dioxin wastes. The EPA mobile incinera-
tor has been used to treat a variety of
waste forms at the Denney Farm in Mis-
souri, but this unit is intended to be
used for research purposes and not as a
commercial treatment process. The
high temperature fluid wall process
(AER) operated by Huber at its Borger,
Texas facility is permitted to perform re-
search on dioxin contaminated wastes
and is also a research tool which is not
intended to be used for actual waste
treatment.
Conclusions
Dioxin wastes, particularly those
dioxin-contaminated soils which ac-
count for over 98 percent of the contam-
inated wastes identified in Table 2, con-
tain low levels (10 to 100 ppb) of dioxins
and/or dibenzofurans. Nonetheless,
many technologies, particularly the
thermal destruction technologies, re-
quire that the total quantity of the waste
be treated to destroy the extremely low
dioxin fraction resulting in very high en-
orgy usage for dioxin destruction. In ad-
dition, when incineration and other
thermal destruction technologies are
used, large quantities of exhaust gases
are generally formed. These waste
streams can contain toxic products of
incomplete combustion (PICs) and
other hazardous emissions. They and
other associated waste streams are
themselves subject to costly treatment
processes. Therefore, technologies
such as solvent extraction or desorp-
tion, which separate the toxic con-
stituents from the waste matrix prior to
final treatment should receive further
investigation
Most of the emerging technologies
are being designed for operation at the
waste source. This trend to portable or
field-erected technologies reflects a re-
action to public opposition to the trans-
port of dioxin waste from source to
waste treatment facilities, and should
continue to be encouraged.
In addition, because of the large vol-
ume of soil contaminated by relatively
low concentrations of dioxin, it is also
important to investigate methods of in-
situ treatment. These methods would
limit the handling of the waste so that
further dispersion of contaminated ma-
terials into the environment is mini-
mized. Most of the technologies in this
category, such as biodegradation, in
situ vitrification, chemical dechlorina-
tion, and stabilization in the near future
have not yet been sufficiently demon-
strated. Use in the near future seems
improbable without more intense de-
velopment of these technologies. Steps
should be taken to encourage these de-
velopments.
The treatment of dioxin contaminated
liquids and low viscosity sludges does
not appear to be as large a problem as
is the treatment of contaminated soils.
This is primarily because the quantity of
liquids and sludges is much lower, and
also because the liquid waste form gen-
erally calls for less extensive handling
and pretreatment. Technologies, such
as plasma arc pyrolisis and supercritical
water oxidation, appear to be capable of
treating these wastes, and their devel-
opment should be fostered, as should
other reasonable activities aimed at the
development of emerging technologies.
Mark Arienti, Lisa Wilk, Michael Jasinski, and Nancy Prominski are with GCA
Corporation, Bedford, MA 01730.
Harry Freeman is the EPA Project Officer (see below).
The complete report, entitled "Technical Resource Document: Treatment
Technologies for Dioxin-Containing Wastes," (Order No. PB 87-110 813/
AS; Cost: $24.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Hazardous Waste Engineering Research Laboratory
US. Environmental Protection Agency
Cincinnati, OH 45268
-------
Center for Environmental Research BULK RATE
Information pnr,T r rccc o\m
Cmonnat, OH 452(^8 POSTAGE & FEES PAID
E PA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/600/S2-86/096
------- |