United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-220)
Directive 9200.5-254FS
November 1989
PA
J7rA\
TECHNOLOGY DESCRIPTION
The glycolate dehalogenation process
is potentially effective in detoxifying spe-
cific types of aromatic organic contami-
nants, particularly dioxins and polychlori-
nated biphenyls (PCBs). The process in-
taminant type, initial concentration of the
contaminant, water content, humic and clay
content (for soils), and the level of treatment
desired. Water is vaporized in the reactor
and collected in a condensate receiver. A
carbon adsorption filter traps any volatile
compounds that are not condensed.
Figure 1: Schematic Diagram of a Typical Glycol Dehalogenation
Trsatmsnt Facility
Water Vapor I o ° o
and Volatiles
Soils and _
Wastes Mmg-
Note: adeptod from Gdoon RomodloBon Corp, tor Booz. Alton 0. Hamilton Inc
volves heating and physically mixing con-
taminated soils, sludges, or liquids with an
alkali metal hydroxide-based polyethylene
glycol reagent in a mobile batch reactor. A
typical glycolate dehalogenation treatment
facility is shown above in Figure 1.
Before treatment, soils are sieved to re-
move any large rocks and/or debris. The
contaminated media are commingled with a
reagent to form a homogeneous slurry. The
reagent primarily consists of potassium or
sodium hydroxide (KOH or NaOH) and
polyethylene glycol (PEG); other reagents
such as dimethyl sulfoxide (DMSO) or sul-
folane (SFLN) may be added to improve the
efficiency of the process. The slurry is si-
multaneously heated (25°C to 150°C) and
mixed, consequently decomposing haloge-
nated contaminants into less toxic, water-
soluble compounds (glycol-ethers and chlo-
ride salts).
Treatment time in the reactor ranges
from 0.5 to 5 hours, depending on the con-
Additional treatment of soils is required
to desorb reaction by-products and reagent
from the dechlorinated soil. This treatment
includes physically mixing the dehaloge-
nated soil with water in successive washing
cycles. The treated soil is then dewatered
and redeposited on-site, while the reagent
and wash waters are recycled and ultimately
treated and/or delisted.
Advantages of glycolate dehalogena-
tion include toxicity reduction of target con-
taminants, mobility of treatment unit, short
treatment time, non-toxic by-products, and
cost-effectiveness relative to conventional
technologies for similar wastes (e.g., incin-
eration).
Disadvantages are that the technology
is limited to halogenated compounds, and
spent reagent, wastewater, and by-products
may require further treatment and/or dis-
posal actions. Applications and limitations
of glycolate dehalogenation are further dis-
cussed in the following sections.
SITE CHARACTERISTICS AFFECTING
TREATMENT FEASIBILITY
Glycolate dehalogenation may be used
to treat multimedia waste containing aro-
matic halides such as dioxins, PCBs, and
chlorobenzenes. The effectiveness of this
treatment on general contaminant groups is
provided in Table 1; however, treatability
tests are required to determine the effective-
ness of glycolate dehalogenation for spe-
cific site conditions.
Factorslimitingtheeffectivenessof gly-
colate dehalogenation include highly con-
centrated contaminants, high water content,
low pH, high humic content (soil), and the
presence of other alkaline-reactive materi-
als (e.g., aluminum, other metals). Site-spe-
cific characteristics and their potential im-
pact are provided in Table 2.
Table 1
Effectiveness o! Glycol Dehalogenation
Treatment on General Contaminant
Groups for Soil and Debris
I
8
I
|
J
Treatability Groups
Halogenated volatiles
Halogenated semi-volaliles
Non-halogenated volatiles
Non-halogenated seml-volatiles
PCBs
Pesticides
Oioxins/Furaris
Organic cyanides
Organic corrosives
Volatile metals
Non-volatile rnetals
Asbestos
Radioactive materials
Inorganic corrosives
Inorganic cyanides
Oxidizers
Reducers
Effectiveness
0
6
O
O
O
G
O
0
O
O
O
O
O
O
O
O
O
Demonstrated Effectiveness
Potential Effectiveness
No Expected Effectiveness
Potentially Detrimental
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Table 2: Site-Specific Characteristics and Impacts on
Glycolate Dehalogenatlon Treatment
Characteristics
Impacting Process
Feasibility
Elevated concentrations ol
chlorinated organics
(greater than 5 percent)
Presence ol aliphatic
organics, inorganics, and
metals
High water content In
waste (greater than 15
percent)
Low pH (less than 2)
Presence ol other
alkaline-reactive materials
(e.g., aluminum, other
metals)
High humic content in soil
Rosoono for
Potential
Impact
Requires excessive volumes
ol reagent; process less cost-
effective
Glycolate dachlorination
ineffective against these
waste groups
Requires excessive volumes
of reagent and Increased
energy input; process less
cost-effective
Requires excessive volumes
of reagent; process less cost-
effective
Reactive materials compete
with contaminants for reagent
Increases reaction time,
process less cost-effective
Actions to
minimize
Impacts
Reagent addition
Employ supplemental
treatment technology (e.g.,
solvent extraction, soil
washing)
Reagent addition;
evaporation of water during
treatment process
Reagent addition, pH
adjustment
Reagent addition
Increase reactor lima
TECHNOLOGY CONSIDERATIONS
The major technology consideration is determining how a large
volume of residual wastewater generated from the soil washing/de-
watering process will be managed. The residual effluent may
require treatment prior to disposal; however, if the volume of waste
water is extremely high (i.e., volumes generated from greater than
30,000 cubic yards of washed soil), it may be more cost-effective to
petition EPA to delist the residual effluent, whereby it may be
disposed without further treatment. Post-treatment options com-
monly employed when treating residual wastewaters may include
chemical oxidation, biodegradation, carbon adsorption, precipita-
tion, or incineration.
Glycolate dehalogenation operations require no special han-
dling [although special handling of contaminated media (e.g., dioxin
contaminated waste) may be required] and energy requirements are
not extreme; therefore, operation and maintenance costs are rela-
tively low. A full-scale dehalogenation unit with a capacity of 80
cubic yards per batch requires an average of 670 kilowatts, with 930
kilowatts peak. A sufficient power source is required and may
present additional costs if a source is not readily accessible. Pre-
construction engineering controls, to guard against accidental spills,
include leveling and lining (synthetic) the areas under and adjacent
to the treatment facility and diking the area surrounding the facility.
TECHNOLOGY STATUS
Numerous vendors presently possess the technology to conduct
full-scale glycolate dehalogenation. Galson Remediation Corpora-
tion (GRC) has reported to have successfully applied full-scale
glycolate dehalogenation at two sites containing PCB-contaminated
waste oil. The GRC full-scale reactor has a single batch capacity of
80 cubic yards and is designed to treat 160 to 200 cubic yards of
waste per day. GRC quotes the average cost ofatreatability test is
between $2,000 and $3,000, depending upon the chemistry of the
target contaminant(s). Treatment costs range from $100 to $300 per
cubic yard; actual costs are contingent upon site-specific character-
istics. A summary of vendors capable of conducting pilot- and/or
full-scale treatment are listed in Table 3.
Mobile glycolate dehalogenation units have been field-tested)
on various waste types and media at numerous CERCLA sites at the
bench- and pilot-scale. These sites include:
0 MonjanaJPole Wood Preserving Site. Butte. Montana - An oily
phase liquid containing 3.0 percent (30,000 ppm) pentachloro-
phenol (PCP) and oil containing up to 84 ppm chlorinated dioxins
and furans were treated to below their respective detection limits.
In total, 9,000 gallons of contaminated oil were treated within 1.5
hours.
° Western Processing Site. Kent. Washington - Heterogeneous
mixtures of oil, solids, and water containing pesticide phosphate
esters and TCDD (up to 120 ppb) were treated to below their
respective detection limits. In total, 7,550 gallons of waste were
treated within 13 hours.
0 P.W.C..Guam - Soils contaminated with Aroclor 1260, ranging in
concentrations from 300 ppm to 2,200 ppm, were treated to below
2 ppm within 5 hours. The high temperature alkaline-glycol treat-
ment process, developed by EPA, operates efficiently without
adding DMSO or SFLN.
EPA has selected glycolate dehalogenation as a component of the
selected remedy for three CERCLA sites. Site names, ROD sign
dates, target contaminants, waste volumes, and media are provided
in Table 4.
Table 3
Vendor Information
Company
Galson Remediation
Corporation
(dechlorination)
S.D. Meyers, Inc.
(dechlorination)
Chemical Waste
Management
(dechlorination)
U.S. EPA. Risk
Reduction Engineering
Laboratory
(dehalogenation)
Contact
Robert Peterson
Edwina Miliric
Joe Kelly
Dick Rosenberg
Alfred Kornel
Charles Rogers
Address
6627 Joy Road
E. Syracuse, NY 13057
(315)436-5160
1 80 South Ave.
Talmage, OH 44278
(216)633-2666
150W. 137th St.
Riverdale, IL 60627
(312)841-8360
26 W. Martin Luther King Drive
Cincinnati, Ohio 45268
(51 3) 569-7421 or 569-7757
OFFICE OF RESEARCH AND DEVELOPMENT CONTACTS
Supplemental information concerning glycolate dehalogena-
tion may be obtained from Charles Rogers, U.S. EPA, Risk Reduc-
tion Engineering Laboratory, Cincinnati, Ohio 45268, (513) 569-
7757 or FTS 684-7757.
Table 4
Glycolate Dehalogenation at CERCLA Sites
SELECTED:
Region 1 - Re-Solve, MA
9/87
Region 2 -Wide Beach, NY
9/85
Region 6 - Sol Lynn, TX
3/88
PCBs in Sediment,
Soil
PCBs (Arochlor
1254) in Soil
PCBs in Soil
3,000 cubic yards sediment
22,500 cubic yards soil '
28,600 cubic yards
Not provided
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