&EPA
United States
Environmental Protection
Agency
Office of
Research and Development
Cincinnati, OH 45268
EPA/540/R-95/536a
February 1997
SITE Technology Capsule
GRACE Bioremediation
Technologies' DARAMEND
Bioremediation Technology
TM
Abstract
GRACE Bioremediation Technologies' DARAMEND™
Bioremediation Technology is an amendment-enhanced
bioremediation technology for soils and sediments contami-
nated with a wide variety of organic contaminants including
chlorinated phenols, polynuclear aromatic hydrocarbons (PAHs)
and petroleum hydrocarbons. The technology may be applied
ex situ to sediment and soil and in situ to near-surface soils.
The technology is based upon the addition of solid-phase
organic amendments of specific particle-size distribution and
nutrient content. The amendments increase the ability of the
soil matrix to supply biologically available water and nutrients
to microorganisms that are capable of degrading the target
compounds. In addition, the amendments bind pollutants to
reduce the acute toxicity of the soil's aqueous phase, thereby
allowing microorganisms to survive in soils containing very
high concentrations of toxicants.
The DARAMEND™ Bioremediation Technology was evalu-
ated under the SITE program at the Domtar Wood Preserving
Facility in Trenton, ON, Canada. The facility formerly treated
wooden poles with solutions of creosote and pentachlorophe-
nol (PCP). Soil at the site is contaminated with chlorinated
phenols and PAHs at concentrations of up to 700 mg/kg and
3,000 mg/kg, respectively.
Results from the SITE Demonstration indicate that the
DARAMEND™ Bioremediation Technology significantly reduced
total chlorinated phenols (TCPs), PAHs, and total recoverable
petroleum hydrocarbons (TRPH) in the contaminated soils.
Toxicity tests, using earthworm mortality and seed germina-
tion inhibition, indicated that the bioremediation process re-
duced the toxicity of the soils to these organisms. Water
balance was successfully maintained to avoid the generation
of contaminant-laden leachate. The DARAMEND™
Bioremediation Technology was implemented without any dif-
ficulties and it generally operated well throughout the demon-
stration period.
The DARAMEND™ Bioremediation Technology was evalu-
ated based on seven criteria used for decision making in the
Superfund feasibility study (FS) process. Results of the evalu-
ation are summarized in Table 1.
Introduction
In 1980, the U.S. Congress passed the Comprehensive Envi-
ronmental Response, Compensation, and Liability Act
(CERCLA), also known as Superfund, which was committed
to protecting human health and the environment from uncon-
trolled hazardous waste sites. CERCLA was amended by the
Superfund Amendments and Reauthorization Act (SARA) in
1986, which calls for long-term effectiveness and perma-
nence of remedies at Superfund sites. SARA mandates imple-
menting permanent solutions and using alternative treatment
technologies or resource recovery technologies, to the maxi-
mum extent possible, to clean up hazardous waste sites.
State and federal agencies, as well as private parties, are
now exploring a growing number of innovative technologies
for treating hazardous wastes. The sites on the National
Priorities List total over 1,700 and represent a broad spectrum
of physical, chemical, and environmental conditions requiring
various types of remediation. The U.S. Environmental Protec-
tion Agency (EPA) has focused on policy, technical, and
informational issues in exploring and applying new remediation
technologies to Superfund sites.
One such initiative is EPA's Superfund Innovative Technology
Evaluation (SITE) program, which was established to acceler-
ate development, demonstration, and use of innovative tech-
nologies for site clean-ups. EPA SITE Technology Capsules
summarize the latest information available on selected inno-
vative treatment and site remediation technologies and re-
lated issues. These Capsules are designed to help EPA
Remedial Project Managers, EPA On-Scene Coordinators,
contractors, and other site clean-up managers understand the
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Table 1. FS Criteria Evaluation for the DARAMEND™ BloremBdiation Technology
N>
Overall Protection of
Human Health and
the Environment
Provides both short-
and long-term protec-
tion by eliminating
organic (PAHs and
TCPs) contaminants
in soil.
Compliance with
Federal ARARs
Requires compliance
with RCRA treatment,
storage, and land dis-
posal regulations (of a
hazardous waste).
Long-Term
Effectiveness
and Permanence
Provides for irrevers-
ible treatment of PAHs
and TCPs.
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
Significantly reduces
toxicity, mobility, and
volume of soil contam-
inants through treat-
ment.
Short-Term
Effectiveness Implementability
Bioremediation proc- Involves few admin-
esses require time istrative difficulties.
for the degradation of
contaminants. Length
of time is based on con-
taminant type, concen-
tration levels, and the
characteristics of the
media.
Cost
A first estimate of costs
is $50 to $80 USD/ton.
The cost is affected by
project parameters such
as contaminant type
and initial concentration;
contaminant target
concentration; soil
volume requiring
remediation; climate;
remediation time frame;
and project scope of
work.
Removes existing
contamination source,
thereby preventing
continual contamina-
tion to other environ-
mental media.
Requires measures
to protect workers
and community
during excavation,
handling, and treat-
ment.
Excavation, construction,
and operation ofonsite
treatment unit may re-
quire compliance with
location specific ARARs.
Process does not gener-
ate significant air emis-
sions or wastewater
•during implementation
or treatment.
Prevents further
ground-water contam-
ination and pollutant
migration.
Eliminates contamina-
tion source, thus re-
ducing the mobility
of contaminants to
other environmental
media.
Volume of soil after
treatment is slightly
increased due to the
addition of treatment
amendments.
System is easy to install
and operate. Uses con-
ventional excavation and
tilling equipment.
May require a green
house type enclosure
to enhance moisture
control and raise the
soil temperature (in
cold climates)
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types of data and site characteristics needed to effectively
evaluate a technology's suitability for cleaning up Superfund
sites.
This Capsule provides information on the DARAMEND™ Biore-
mediation Technology. The technology may be applied to the
remediation of soils and sediments contaminated with a wide
variety of organic contaminants including chlorinated phenols,
PAHs, and petroleum hydrocarbons. The technology may be
applied ex situ to sediment and soil and in situ to near-surface
soils. The bipremediation process has three components: addi-
tion of a solid phase organic soil amendment, homogenization
and aeration of the soil/amendment using specialized tilling
equipment, and maintenance of soil moisture. GRACE
Bioremediation Technologies' DARAMEND™ Bioremediation
Technology was evaluated under EPA's SITE program during
an 11-mo period from October 1993 to September 1994 at the
Domtar Wood Preserving Facility in Trenton, ON, Canada. The
DARAMEND™ technology was evaluated to assess its effec-
tiveness in treating excavated soils contaminated with chlori-
nated phenols (mainly pentachlorophenol) and PAHs.
Information in this Capsule is based on specific site character-
istics and results of the SITE Demonstration at the Domtar site.
This Capsule presents the following information:
Abstract
Technology description
Technology applicability
Technology limitations
Process residuals
Site requirements
Performance data
Technology status
Sources of further information
Technology Description
The DARAMEND™ Bioremediation Technology treats soils and
sediment contaminated with a wide variety of organic contami-
nants including chlorinated phenols, PAHs, and petroleum hy-
drocarbons. The process accelerates degradation of the target
compounds by stimulating indigenous soil microbes. In addi-
tion, the process allows remediation to proceed in toxic soils
contaminated with high levels of PCP.
Technology application requires contaminated soil to be
screened to approximately 10 cm to remove debris (rocks,
wood, metal) that could interfere with the incorporation of the
organic amendments. In situ, the soil is screened to a depth of
60 cm using equipment such as subsurface combs and agricul-
tural rock pickers. Ex situ, the soil is passed over a mechanical
screen. For ex situ applications, screened soil is transported to
the treatment area and deposited into a low permeability cell (a
high density polyethylene-lined earthen cell or a concrete cell).
The contaminated soils, to a maximum depth of 0.6 m, are
mixed with amendments and periodically tilled and irrigated to
encourage the growth of contaminant-degrading microbiota. A
cover may be used to control soil moisture content and elimi-
nate run-on/run-off. Covering the plot has the added benefit of
raising soil temperature to accelerate remediation in cold cli-
mates. Irrigation and tillage continue until the concentrations of
target compounds have fallen below mandated cleanup levels.
The length of time required for remediation is based on many
factors including the type and concentrations of contaminants,
soil temperature, and soil chemistry.
The DARAMEND™ Bioremediation Technology consists of three
innovative processing components which, in tandem, constitute
the remediation technology:
• Addition of solid-phase organic soil amendments ot specific
particle-size distribution and nutrient content.
• Distribution of the soil amendments through the target matrix
and the homogenization and aeration of the target matrix
using specialized tilling equipment.
• A specialized soil moisture control system designed to main-
tain moisture content within a specified range to facilitate
rapid growth of an active microbial population and prevent the
generation of leachate.
The organic amendments increase the ability of the soil matrix
to supply biologically available water and nutrients to microor-
ganisms that are capable of degrading the target compounds.
The amendments also bind pollutants to reduce the acute
toxicity of the soil's aqueous phase, thereby allowing microor-
ganisms to survive in soils containing very high concentrations
of toxicants.
Selection of a soil amendment is based on treatability and pilot-
scale investigations, because the physical and chemical prop-
erties of the target soil dictate the type of amendment to be
used. Relevant soil physical properties include textural varia-
tion, percent organic matter, and moisture content. Relevant
soil chemical properties include soil pH, macro- and micro-
nutrients, metals, and the nature and concentration of soil
contaminants.
Periodic tilling of the soil increases diffusion of oxygen to
microsites and ensures uniform distribution of irrigation water in
the soil. Tilling is performed immediately after amendment
addition and at 2-wk intervals thereafter.
Soil moisture is maintained within a specific range below the
soil's water holding capacity. Maintenance of soil moisture
within this narrow range is critical to effective biodegradation of
the target compounds. In the presence of excess moisture,
diffusion of oxygen through the soil matrix to microbially active
microsites can be limited by a low ratio of air-filled to water-
filled pores. Conversely, if soil moisture falls below the optimum
range biodegradation can be inhibited because of inadequate
biologically available water.
Technology Applicability
The DARAMEND™ Bioremediation Technology is applicable to
a wide range of organic contaminants deposited to soil or
sediment. The technology has been applied to soils at pilot-
scale with total PAH concentrations up to 18,500 mg/kg, total
petroleum hydrocarbons up to 8,700 mg/kg, and pentachlo-
rophenol to 660 mg/kg. PAHs, total petroleum hydrocarbons
and pentachlorophenol have been reduced to meet Canadian
guidelines for industrial soils. Under the Great Lakes Clean up
Fund's Contaminated Sediment Treatment Technology Pro-
gram, GRACE Bioremediation Technologies' DARAMEND™
Bioremediation Technology treated 150 tons of dredged harbor
sediment. In approximately 300 days of ex situ treatment the
level of total PAH contamination was reduced from approxi-
mately 1,000 mg/kg to 100 mg/kg - a removal efficiency of
approximately 90%. Bench-scale work has resulted in the de-
velopment of new technology for remediation of soil and sedi-
ment contaminated with phthalates, organochlorine pesticides
and organic explosives. For example, total phthalates were
reduced from 7,710 mg/kg to 47 mg/kg in soil, p,p-DDT, an
organochlorine pesticide, was reduced from 684 mg/kg to 1.9
mg/kg in soil and 2,4,6-trinitrotoluene (TNT), an organic explo-
sive, was reduced from 7,200 mg/kg to 19 mg/kg in soil, all
exhibiting a greater than 99% removal efficiency.
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Technology Limitations
Th0 DARAMEND™ Bioremediation Technology appears to be
limited to soils contaminated with non-halogenated and certain
halogenated organic compounds. The technology may become
technically or economically infeasible when dealing with soils
with excessively high contaminant concentrations. The devel-
oper claims that the technology would probably not treat soils
contaminated with polychlorinated biphenyls (PCBs) or highly
halogenated organics. In addition, high levels of heavy metals,
soil pH <2, and excessive amounts of buried debris may limit
the rate at which biodegradation proceeds. Furthermore, the in
situ application of the technology is limited to the depth to
which the soil can be physically tilled. Ex situ applications of
tha technology may be limited by community acceptance of the
inherent hazards (e.g., noise, dust, etc.) associated with exca-
vation activities.
Of course, a number of natural physical and chemical factors
may affect the activity and longevity of contaminant-degrading
microorganisms in general. The DARAMEND™ Bioremediation
Technology addresses many of these factors directly (i.e.,
moisture content, soil particle size distribution, clay content,
nutrient limitations, and oxygen limitations). In addition, some
factors (i.e., temperature) are indirectly addressed by imple-
mentation of the DARAMEND™ Bioremediation Technology.
For instance, a cover (i.e., greenhouse) used for moisture
control also adds inherent heat value.
Process Residuals
Large particles of debris, stone, and construction material that
are removed from the site prior to bioremediation may require
disposal. Otherwise, virtually no solid waste streams are gener-
ated by the DARAMEND™ Bioremediation Technology.
If a treatment area cover (i.e., greenhouse) is not used, exces-
sive precipitation in the treatment area may generate leachate
or storm water run-off. Excess precipitation is contained in the
lined treatment cell and is minimized by the soil moisture
control system.
Volatile organic compound emissions may increase during soil
tilling. However, previous studies by the developer have indi-
cated that these emission levels are below permissible expo-
sure limits.
Site Requirements
The key requirements for the application of the technology are
available utilities and space.
The utilities required are a source of water (either city, surface,
or subsurface) and electricity rated at 115 V. Water is used
primarily for irrigation but also for dust control and decontami-
nation. When a greenhouse is used as a cover for the treat-
ment plot, electricity is required for fans that separate the two
layers of polyethylene in the greenhouse cover.
Cleared land is required for the treatment area, pretreatment
(i.e., screening) equipment, temporary storage of debris re-
moved from the soil, and storage of the tillage equipment.
Simple laboratory equipment (i.e., ovens and pH meters) on-
site is advantageous but not necessary.
Common to all remediation technologies are office, toilet, and
decontamination facilities.
Performance Data
The GRACE Bioremediation Technologies' DARAMEND™
Bioremediation Technology SITE Demonstration was conducted
to evaluate the performance of the developer's technology in
remediating excavated soils contaminated with PAHs and chlo-
rinated phenols from the Domtar Wood Preserving Facility in
Trenton, ON, Canada. The Domtar Wood Preserving Facility
formerly treated wooden poles with solutions of creosote and
pentachlorophenol. No wood has been treated at the Domtar
site since 1990. The facility is presently used to stockpile
wooden poles and railroad ties.
According to the developer, the DARAMEND™ technology is
an effective bioremediation alternative for the treatment of soils
containing levels of chlorinated phenols and PAHs typically
considered too toxic for bioremediation.
The developer claimed that the DARAMEND™ Bioremediation
Technology could achieve a 95% reduction in total PAHs and a
95% reduction in total chlorophenols over an 8-mo period.
Performance was evaluated by comparing the pre- and post-
treatment concentrations of each list of analytes presented
below:
Total Chlorophenols (TCPs)
2-chlorophenol
2,4-dichlorophenol
2,4,6-trichlorophenol
2,4,5 trichlorophenol
pentachlorophenol
Total PAHs
naphthalene
acenaphthylene
acenaphthene
fluorene
phenanthrene
anthracene
fluoranthene
pyrene
benzo(a)anthracene
chrysene
benzo(b)fluoranthene
benzo(k)fluoranthene
benzo(a)pyrene
indeno(1,2,3-c,d)pyrene
debenzo(a, h)anthracene
benzo(g,h,i)perylene.
Since the process is temperature-dependent, the treatment
period of 254 calendar days included only the days when the
average daily soil temperature within the greenhouse was
above15°C.
The SITE Demonstration was designed to determine whether
the developer's claim could be achieved during a full-scale field
application of the technology. To evaluate the developer's
claims two test plots were constructed and used for this dem-
onstration: a 6 x 36 m Treatment Plot and a 2 x 6 m No-
Treatment Plot. Both the Treatment and No-Treatment Plots
were underlain with a high-density polyethylene liner (imperme-
able to the target compounds). This liner was underlain with 10
cm of screened sand to prevent structural damage to the liner.
Another 15-cm thick sand layer and a 4-mm thick fiber pad
were spread on top of the liner to minimize the potential for
direct contact between the liner material and tillage equipment.
The target test soil was then screened to less than 1-in.
diameter and deposited on top of the sand layer to a thickness
of 0.5 m across both plots. The No-Treatment Plot was isolated
from the Treatment Plot by wooden partitions and covered with
plastic sheeting. The Treatment Plot underwent treatment with
the DARAMEND™ technology while the No-Treatment Plot
received no treatment and was left idle throughout the demon-
stration period.
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The demonstration objective was accomplished by comparing
the total concentrations of select PAHs and of chlorinated
phenols prior to application of the DARAMEND™ technology
and after approximately 11 mo (254 days) of treatment. Four
sampling events were implemented during the course of this
study: a baseline event in October 1993, an initial intermediate
event in April 1994, a second intermediate event in June 1994,
and the final event in September 1994.
The Treatment Plot was subdivided into 54 2x2 m subplots.
Soil samples for critical analyses were collected from 18 sub-
plots within the Treatment Plot throughout the demonstration.
These subplots were selected using a random number genera-
tor. Homogenized soil cores from each of the 18 subplots were
analyzed for Semivolatile Organic Compounds using SW846
Method 3540/8270.
Other objectives of the demonstration included determining the
toxicity of the soil to earthworms and seed germination in each
of the SITE Demonstration plots before and after treatment,
monitoring the fate of TRPH in each of the SITE Demonstration
plots, monitoring general soil conditions (i.e., nutrients, toxics)
that might inhibit or promote process effectiveness, monitoring
for leachate within the SITE Demonstration Treatment Plot,
monitoring each of the SITE Demonstration plots for active
microbial populations, and monitoring the upper sand layer in
contact with the treated soil to qualitatively assess any ten-
dency for downward migration of contaminants.
Results from the SITE Demonstration indicate that the
DARAMEND™ Bioremediation Technology significantly reduced
PAH, TCP, and Total Recoverable Petroleum Hydrocarbons
(TRPH) in the Treatment Plot. PAHs were reduced from 1,710
mg/kg to 98 mg/kg (94.3% reduction), total chlorophenols were
reduced from 352 mg/kg to 43 mg/kg (87.8% reduction), and
total recoverable petroleum hydrocarbons were reduced from
7,300 mg/kg to 932 mg/kg (87.3% reduction).
Results from the No-Treatment Plot indicate no significant
decreases in TCPs and TRPH in the soil. Total chlorophenols
remained at approximately 217 mg/kg, and TRPH remained at
approximately 5,000 mg/kg. However, polyaromatic hydrocar-
bons were reduced from 1,312 mg/kg to 776 mg/kg, represent-
ing a 40.9% reduction. Table 2 summarizes the analytical
results from the demonstration.
Toxicity tests were performed on baseline and post-remediation
soil samples to determine if the toxicity of the soil had de-
creased due to the DARAMEND™ Bioremediation Technology.
Two toxicity tests were used: germination inhibition of lettuce
and radish seeds, and earthworm mortality. The DARAMEND™
Bioremediation Technology appeared to reduce the toxicity of
the contaminated soil to both the plant seeds and the earth-
worms. Toxicity tests indicate that the baseline soils in the
Treatment and No-Treatment Plots were toxic to the test or-
ganisms. Post-remediation soil toxicity was only slightly re-
duced in the No-Treatment Plot, while soil in the Treatment
Plot was essentially non-toxic to the earthworms and radishes
and only slightly toxic to lettuce germination at the end of the
study. The slight reduction in toxicity of the No-Treatment Plot
is consistent with the slight reductions in PAHs observed.
Tables 3 and 4 present the results of the toxicity tests.
The DARAMEND™ Bioremediation Technology did not gener-
ate leachate. Water balance was successfully maintained to
avoid the generation of contaminated leachate. If generated,
this leachate would require treatment prior to discharge.
The DARAMEND™ Bioremediation Technology was imple-
mented without any difficulties and it generally operated well
throughout the demonstration period. One exception was the
mixing of some of the underlying sand into the soil/amendment
mixture during tilling. This resulted in an overall increase in the
volume of soil/amendment at the end of the study.
Technology Status
The DARAMEND™ technology has successfully remediated
1,500 tons of soil ex situ and 3,500 tons of soil in situ (2 ft of
near-surface soil) at the former Domtar Wood Preserving Facil-
ity. The remediated soil met clean-up criteria set by the Cana-
dian Council of Ministers for the Environment, including a 5
mg/kg criterion for PCP. In 1995, treatment of a second 1,500-
ton batch of soil was initiated at the site. Also in 1995, full-scale
treatment of 2,500 tons of soil was initiated at a former wood
preserving site in eastern Canada.
In the United States during 1996, the DARAMEND™ technol-
ogy was successfully applied at full scale at a former wood
preserving site in Minnesota. Late in 1996, a large-scale field
treatability demonstration was initiated in association with re-
medial actions at the Montana Pole Superfund site in Butte,
MT. Commencement of a full-scale project is planned for the
summer of 1997 in Washington state.
Key developmental work on the technology is focusing on
improving kinetics and expanding applicability with respect to
contaminant type. The range of contaminants effectively dealt
with by the DARAMEND™ technology has now been expanded
to include phthalates. Concentrations of phthalates have been
rapidly reduced from thousands to less than 100 mg/kg during
bench-scale studies and pilot-scale work at a site in New
Jersey in 1996.
In addition, a second generation DARAMEND™ technology has
been developed by GRACE Bioremediation Technologies. The
hew technology rapidly reduces concentrations of organochlo-
rine pesticides (e.g., DDT and Toxaphene™) and organic ex-
plosives (e.g., TNT) in soil. Extensive laboratory testing has
been completed. Pilot-scale pesticide projects commenced in
1996 in South Carolina and Ontario, Canada, and will continue
in 1997. A pilot-scale project to demonstrate remediation of
explosives-contaminated soil is expected to commence in 1997.
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Table 2, Results from the DARAMEND™ SITE Demonstration
Baseline
Anafyta
Total PAHs
TCPs
TRPH
No Treatment Plot
Total PAHs
TCPs
TRPH
Sampling 1
October 1993
1,710
352
7,300
1,312
217
5,000
Sampling 2
April 1994
619
158
NA
1,155
288
NA
Post Treatment
June 1994
Treatment Plot
221
90
NA
982
356
NA
September 1994
98
43(13.6)1
932
776
218 (240)1
5,200
Overall %
Reduction
94.3
87.8(96.1)1
87.3
40.9
0(0)1
0
AN data Is mg/kg on a dry weight basis.
NA - Not analyzed.
PAHs - Polynuclear Aromatic Hydrocarbons.
TCPs - Total Chlorinated Phenols.
TRPH - Total Recoverable Petroleum Hydrocarbons.
-Data provided by GRACE Bloremedlation Technologies, based on analyses of split samples by an independent laboratory.
Table 3. Mortality of the Earthworm, Eisenia Foetlda, from 28-Day Soil Toxicity Tests
Mean Percent Mortality
Baseline
(October 1993)
Post-Treatment
(September 1994)
DARAMEND™ Treated Soil
100% (0%)
0% (3%)
Untreated Soil
100% (0%)
100% (3%)
Values reported are the mean percent mortality in the 100% treated and untreated soil before and after remediation. Paired negative control
mortality is In parentheses.
Table 4. Inhibition of Germination from 5-Day Soil Toxicity Tests Conducted with Lettuce (Lactuca Saliva) and Radish (Raphanus Sativus)
Mean Percent Inhibition of Germination
Baseline
(October 1993)
Post-Treatment
(September 1994)
DARAMEND™ Treated Soil
Lettuce Radish
100% (8%) 52% (4%)
33% (5%) 0% (1%)
Untreated Soil
Lettuce
97% (5%)
92% (5%)
Radish
82% (9%)
23% (1%)
Vakies reported are the mean inhibition of germination in 100% untreated and treated soil before and after remediation. Paired negative control
Inhibition of germination is in parentheses.
Source of Further Information
EPA Contact:
Teri L. Richardson
U.S. EPA NRMRL
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7949
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1
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United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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