S-EPA
United States
Environmental Protection
Agency
EPA/540/MR-92/015
November 1992
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
So/7 Recycling Treatment Train
The Toronto Harbour Commissioners
-Introduction: The Toronto Harbour Commissioners (THC) have
developed a soil treatment train designed to treat inorganic and
organic contaminants in soils. THC has conducted a large-scale dem-
onstration of these technologies in an attempt to establish that con-
taminated soils at the Toronto Port Industrial District can be treated to
attain contaminant levels below the Modified Ontario Ministry of the
Environment (MOE) Criteria Levels for Industrial Soils without utilizing
incineration processes. This Superfund Innovative Technology Evalua-
tion (SITE) of the on-going THC Demonstration was undertaken to
provide a consistent basis for comparing these technologies to other
technologies evaluated under the SITE program.
Technology Description: The THC's treatment train consists of
three soil remediation technologies: a soil washing technology, a
technology that removes inorganic contamination by chelatbn, and a
technology that utilizes chemical and biological treatment to reduce
organic contaminants.
The process utilizes an attrition soil wash plant to remove relatively
uncontaminated coarse soil fractions using mineral processing equip-
ment while concentrating the contaminants in a fine slurry which is
routed to the appropriate process for further treatment. The wash
process includes a trommel washer to remove clean gravel,
hydrocyfones to separate the contaminated fines, an attrition scrubber
to free fines from sand particles, and a density separator to remove
coal and peat from the sand fraction.
If only inorganic contaminants are present, the slurry can be treated in
the inorganic chelator unit. This process uses an acid leach to free the
inorganic contaminant from the fine slurry and them removes the rneta!
utilizing solid chelating agent pellets in a patented countercurrent
contactor. The metals are recovered by electrowinning from the chelat-
ing agent regenerating liquid.
Organic removal is accomplished by utilizing a chemical pretreatment
of the slurry from the wash plant or the metal removal process and
biological treatment in upflow slurry reactors utilizing the bacteria which
have developed naturally in the soils being treated. The treatment soil
is dewatered utilizing hydrocyclones and transported back to the site
from which it was excavated.
A process fbw diagram for these processes in a configuration which
would be used for soils highly contaminated with organic and inorganic
contaminants is shown in Figure 1.
Waste Applicability: The technology is designed to reduce organic
and inorganic contaminants in soils found at industrial and commercial
-sites. The process train approach is'most useful when sites have been"
contaminated as a result of multiple uses over a period of time. Typical
sites where the process train might be used include refinery and
petroleum storage facilities, sites with metal processing and metal
recycling histories, and manufactured gas and coal/coke processing
and storage sites. The process is less suited to soils with undesirable
high inorganic constituents which result from the inherent mineralogy
of the soils.
Demonstration Results: The THC SITE Demonstration of these
technologies took place in the first half of 1992 at a temporary pilot
facility constructed at a site within the Toronto Port Industrial District.
The sampling associated with this SITE project took place in April and
May of 1992 when the pilot unit was processing a soil from a site which
has been used for metals finishing and refinery and petroleum storage.
Reid characterization of the soils indicated that organic and inorganic
treatment would be required. When working quantities of the soil were
excavated, it was determined that the metals contamination was very
bw and therefore no inorganb processing was required. The sampling
and analysis centered on the soil washing and bbbgbal treatment
process. The developer did operate the metals removal process during
the sampling period in order to complete the processing of the soil from
another site where high metals levels were encountered. A modified
sampling program for the metals removal process was implemented in
the field to provide an engineering assessment of this technology.
The project objective was to achieve the Modified MOE Criteria Levels
for Clean Soil for Commercial/industrial Sites. An abbreviated list of the
criteria which proved important in this study is presented in Table 1.
Table 1. Abbreviated MOE Criteria for Commercial/Industrial Site Soils
I Oil and Grease 1%
\ Naphtfialene S.Qgfcg
Benzo(a)pyrene 2.4 mg/kg
In additbn, the objectives included an assessment of the removal
efficiencies for the various undesirable constituents by the individual
processes. Gaseous emissbns from the biotreatment process were
also sampled.
I
Composite samples were collected from all feed and product streams
and from process streams where data were required to assess the
performance of the processes. Process operating data were accumu-
lated to define operating conditions during the Demonstratbn sam-
pling. Laboratory activities conducted for the Demonstratbn included
i'
,^ Printed on Recycled Paper
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Sand
>63 microns
Coal Post
Feed
Hopper
Trommel
Washer
Soil >6 mm
Fine Soil
Regenerating
Acid
Metals
Ffgum 1. Simplified process flow diagram.
analysis of metals, semh/olatile organic compounds, a number of
conventional parameters, and soil physical characteristics.
The Demonstration showed that:
• Soil washing was effective in producing dean coarse soil fractions
and concentrating the contaminants in the fine slurry.
Feed
.8mg/kg
11 mg/kg
2mg/kg
Clean Sand
.2 mg/kg
2mg/kg
.5 mg/kg
Contamincted
FineSluny
4 mg/kg
52 mg/kg
10 mg/kg
Oil & Grease
Naphthalene
Benzo (A) Pyrene
Thechemicaltreatmentprocess and biological slurry reactors, when
operated on a batch basis with a nominal 35 day retention time,
achieved at least a 90% reduction in simple PAH compounds such
as Naphthalene, but fell just short of the approximately 75% reduc-
tion in Benzo(a)pyrene required to achieve the MOE criteria
Contaminated Treated
Rne Slurry Rne Slurry
Naphthalene
Benzo (A) Pyrene
52 mg/kg
10 mg/kg
<5 mg/kg
2.6 mg/kg
• The biological process discharge did not meet the MOE criteria for
oil and grease and the process exhibited virtually no removal of this
parameter. Thedeveloper believesthatthe high outlet oil and grease
values are the result of the analytical extraction of the biomass
. developed during the process.
• The hydrocydone dewatering device did not achieve significant
dewatering. Final process slurries were returned to the excavation
site in liquid form. The development of an acceptable dewatering
process will require further evaluation of alternative technology.
• The metals removal process achieved a removal efficiency fortoxic
heavy metals such as copper, lead, mercury and nickel of approxi-
mately 70%.
• The metals removal process equipment and chelating agent were
fouled by free oil and grease contamination; forcing the curtailment
ofsamplingprematurely.Thisestablishesalimitatfonforthistechnol-
ogy since biological treatment or physical separation of oil and
grease will be required to avoid such fouling.
An Application Analysis Report and a Technical Evaluation Report
describing the complete Demonstratfon will be available in the Spring
of 1993.
For Further Information:
EPA Project Manager
Teri Richardson
U.S. EPA Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
(513) 569-7949
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
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EPA
PERMIT No. G-35
EPA/540/MR-92/015
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