vvEPA
United States
Environmental Protection
Agency
EPA/540/S5-89/011
December 1990
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Technology Demonstration
Summary
Chemfix Solidification/
Stabilization Process,
Clackamas, Oregon
ChemfIx's* patented stabilization/so-
lidification technology was demon-
strated at the Portable Equipment
Salvage Company (PESC) site in
Clackamas, Oregon, as part of the Su-
perfund Innovative Technology Evalua-
tion (SITE) program. The Chemfix
process is designed to solidify and sta-
bilize hazardous wastes in liquids,
sludges, soils, and ashes using propri-
etary additives.
The PESC site operated as a trans-
former and metal salvage facility from
the 1960s until 1985. Operations at the
site involved scrapping and recycling
power transformers containing poly-
chlorinated biphenyls (PCBs) in oils.
Salvageable metals from Internal wiring
and transformer carcasses were pro-
cessed and recycled. The activities left
the soils at the site heavily contaminated
with lead, copper, and PCBs as well as
other metals and oil.
Based on performance claims and
previous treatment data submitted by
Chemfix, the objective of the demonstra-
tion was to determine the ability of the
process to effectively limit the mobility
Mention of trade names or commercial products does
not constitute endorsement or recommendation for
use.
of the metal contaminants, as measured
by the toxicity characteristic leaching
procedure (TCLP), and to create an envi-
ronmentally durable product, as indi-
cated by the physical properties of the
treated waste.
At least 65% of the treated waste
samples from the Chemfix solidification/
stabilization process met the land ban
standard and soil standard established
for the demonstration. Reductions of
teachable lead, as measured by the TCLP,
ranged from 94% to 99%.
The Chemfix process generally pro-
duced treated material with acceptable
physical properties. The treated material
had properties that indicated long-term
durability In exposed environments.
Volume Increase in the excavated mate-
rial after treatment ranged between 20%
and 50%.
This Summary was developed by
EPA's Risk Reduction Engineering
Laboratory, Cincinnati, OH, to announce
key findings of the SITE Program dem-
onstration that is fully documented In
two separate reports (see ordering Infor-
mation at back).
Introduction
In response to the Superfund Amend-
ments and Reauthorization Act of 1986
(SARA), the U.S. Environmental Protection
Printed on Recycled Paper
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Agency's (EPA's) Offices of Research and
Development (ORD) and Solid Waste and
Emergency Response (OSWER) have es-
tablished a formal program to accelerate
the development, demonstration, and use
of new or innovative technologies as alter-
natives to current containment systems for
hazardous wastes. This program is called
the Superfund Innovative Technology
Evaluation program or SITE.
The SITE demonstration of the Chemfix
stabilization/solidification technology began
on March 3,1989, and continued until March
24, 1989. EPA conducted the demonstra-
tion at the Portable Equipment Salvage
Company (PESC) site in Clackamas, Or-
egon. During the demonstration, 7 to 8 yd3
of material were excavated from each of
four areas of the site, treated with the
Chemfix process, and analyzed for physical
and chemical properties.
A data quality objectives (DQO) pro-
gram was used to define the objectives of
the Chemfix process demonstration before
site selection. The objectives of the sam-
pling and analysis program were to mea-
sure:
Front End Loader
The ability of the Chemfix process to
meet or be below land disposal re-
striction levels for heavy metal wastes
(specifically, lead concentrations less
than 0.51 mg/L in the TCLP extract)
established by EPA. In addition, a
demonstration-specific soil standard
of 5.0 mg/L in the TCLP extract was
used.
• The effectiveness of the Chemfix pro-
cess to reduce the mobility of heavy
metals (specifically lead and copper)
and PCBs after treatment using the
TCLP test (based upon percent re-
duction in the concentration).
The physical properties of waste
treated by the Chemfix process. These
physical properties are an indication
of the product's long-term durability
and ability to reduce leaching.
• The ability of the process to dechtori-
nate PCBs.
Process Description
The Chemfix process is a solidification/
stabilization process that can treat solids,
liquids, and sludges provided the wastes
are between 8% and 75% solids by weight
during processing. This technology uses
the folio wing materials, measured by weight
or volume and added to a continuous pro-
cess:
Waste material
• CHEMSET 1-20 dry reagent (a
cementitious agent)
• CHEMSET C-220 liquid reagent (a
patented silicate reagent)
• Water
Figure 1 shows a schematic of the
Chemfix equipment used for the PESC site.
The Chemfix treatment system is a mo-
bile, self-contained, continuous processing
unit mounted on a flatbed trailer. It solidifies
and stabilizes wastes based on chemical
reactions of complex silicates. H is intended
to treat heavy metals and organic com-
pounds with high molecular weights. The
innovative features of the system include
the proprietary reagents, the pug mill de-
signed by Chemfix, and the continuous na-
ture of the process. Because it is a
continuous process, waste material can be
Conveyor
Hopper with Even Feeder
Legend
Transmitter
(p) Controller
Variable Speed
Feed Pump
Alarms and Control
Panel No. 1
Chute to Truck
Loading Area
Figure 1. Flow diagram of Chemfix Technologies, Inc., high solids handling system.
2
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treated more quickly, thus lowering the
cost perton of materialtreated. The process
creates either a friable, soil-like product or
a monolithic solid.
Chemfix indicates three classes of re-
actions occur as part of the treatment.
First, soluble silicates react with cations in
the matrix to form immobile silicates. Sec-
ond, the siliceous setting agents react with
the remaining soluble silicates to produce
a gel structure. Finally, hydrolysis, hydra-
tion, and neutralization occur to further
stabilize the waste.
Site Description
EPA selected the PESO site for the
demonstration because the wastes on the
site were suitable for evaluating the dem-
onstration objectives described above. The
site operated as a transformer and metals
salvage facility from the early 1960s to
1985. Operations at the site involved
scrapping and recycling power transform-
ers containing PCBs in cooling oils. Sal-
vageable metals from internal wiring and
transformercarcasseswereprocessedand
recycled. Transformers and other recycled
electrical equipment were burned in a fur-
nace to eliminate insulation and other
noneconomic elements. Waste transformer
oil was used to fire furnaces and metal
smelters at the site.
EPA designed the predemonstration
sampling activities to isolate waste areas
that were sufficiently different in soil type or
contaminant concentration so the process
would operate over a range of characteris-
tics. This design allowed the limits of the
process to be defined. The four selected
areas, identified as having different char-
acteristics, are described in Table 1. The
data showed ranges of contaminant con-
centrations and a large percentage of de-
bris, both of which are common on
uncontrolled hazardous waste sites. It
should be noted that some lead concentra-
tions encountered at the site were very
high (up to 139,000 mg/kg).
Demonstration Procedures
Before the demonstration began, the
site was prepared for the work. EPA mobi-
lized equipment, provided utilities, and built
decontamination facilities and storage ar-
eas. Approximately 7 to 8 yd3 of contami-
nated soil were excavated from each of the
four selected areas. The waste was mixed
and loaded on top of a 1-in. screen to
separate the large particles (greater than 1
in. in diameter) from the small particles,
because the process normally does not,
and cannot, treat material greaterthan 1 in.
in diameter. The rejected material was
about 30% to 40% of the original quantity of
material.
Table 1. Waste Areas Evaluated During the Chemfix SITE Demonstration (Predemonstration
Sampling)
Area Description
~~ASoil- High lead and copper concentrations (10,000 to 139,000 mg/kg)
Medium to high PCB concentrations (100 to 1,940 mg/kg)
C Soil - High lead and copper concentrations (up to 117,000 mg/kg)
High PCB concentrations (up to 1,350 mg/kg)
E Soil- High lead and copper concentrations (up to 110,000 mg/kg)
Low PCB concentrations (<100 mg/kg)
F Ash- High lead and copper concentrations (40,000 to 136,000 mg/kg)
Medium PCB concentrations (200 to 300 mg/kg)
Table 2. Leaching Tests Used in the Chemfix SITE Demonstration
Name of Test Reference Description
TCLP' 40 CFR Part 268
MJEP* EPA Method 1320 (SW-846)
ANS 16.1 American Nuclear Society 16.1
Ground material subject to 18-hr
extraction process with acetic acid
leachate to simulate an environment
ofcodisposal with municipal waste
Ground material subject to 24-hr
extraction with acetic acid leachate
followed by nine sequential extractions
with acidic-rain-simulated leachate
Monolithic material placed in distilled
water that is replaced over discrete
time intervals (diffusion model)
' Toxicity characteristic leaching procedure
* Multiple extraction procedure
Table 3. Physical and Chemical Tests Used in the
Name of Test Reference
Chemfix SITE Demonstration
Description
Unconfined compressive ASTM D 1633
strength (UCS)
Hydraulic conductivity
Wet/dry resistance
Freeze/thaw resistance
Oxidation/reduction
Electrical conductivity
EPA Draft Protocol
ASTM D 4843
ASTM D 4842
EPA Method 9045
(modified)
ASA 10.-3.3
Assesses structural integrity
of monolith
Assesses resistance of material
to water flow
Indicates durability in
wet/dry environment
Indicates durability in
freeze/thaw environment
Determines oxidation/
reduction state of waste
matrix
Determines amount of ionic
materials present in solution
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Chemfix personnel used the Chemfix
equipment for five runs: a calibration run
with clean sand and one production run for
waste from each of the four areas of the site.
Each run was relatively short, involving 4 to
6 yd3 of material. The Chemfix equipment
used at the site is designed to treat 75 to 100
yd3/hr. The very small quantities used for
the demonstration may have affected the
mixing performance of the process equip-
ment, because of limited calibration time.
The quantity of material treated forthe dem-
onstration was limited to minimize the quan-
tity of treated material that had to be disposed
of after the demonstration.
Sampling and Analysis
Procedures
Raw soil samples obtained the day of
the demonstration and treated soil samples
taken immediately after processing were
tested to provide statistical comparisons of
the physical and chemical characteristics of
the soils. Leaching test samples were formed
in plastic or cardboard molding tubes to
eliminate destruction of samples or per-
ceived interferences of leaching results from
coring operations. Table 2 describes the
leaching tests and Table 3 the physical and
chemicals tests used in the demonstration.
Demonstration Results
Leaching Tests
Two standards were established for de-
termining the ability of the process to stabi-
lize wastes. The first standard was a
concentration of lead less than 0.51 mg/L in
the TCLP extract. This standard is based on
the Land Disposal Restrictions for electro-
plating wastes (EPA listed waste F006).
The second standard, a concentration of
lead less than 5.0 mg/L in the TCLP extract,
was arbitrarily chosen as a demonstration
standard for soils, because soils may be
more difficult to treat than sludges. These
two standards were chosen to provide a
range of standards within which the Chemfix
technology was expected to operate for
contaminated soils.
Sixty-five percent of all samples tested
from all areas of the site passed the stan-
dard of 0.51 mg/L lead in the TCLP extract.
Seventy percent of all samples tested
passed the standard of 5.0 mg/L lead in the
TCLP extract.
The data from the demonstration indi-
cated substantial reductions in the mobility
of lead, copper, and zinc in the treated
wastes compared with that in the untreated
wastes, as determined by the TCLP. Table
4 shows that the reductions in lead concen-
trations ranged from 94% in Area E to 99%
in Areas A, C, and F. The nature of the TCLP
needs to be considered when evaluating
these data. The TCLP is used to evaluate a
waste's potential for leaching contaminants
when the waste is codisposed with munici-
pal wastes. This scenario may not be an
appropriate disposal scenario for the PESC
site.
The reduction in mobility of PCBs, based
on the TCLP, could not be determined since
the PCBs did not leach from the raw waste
with that extraction procedure. More strin-
gent leaching or extraction tests would be
Table 4. Mean Concentration of Lead and Copper from the Chemfix Demonstration
Percent
Reduction
Untreated
Waste
(Total)
TCLP From
Untreated
Waste
TCLP From
Treated
Waste
of TCLP
Extractable
Metal
Area A
Lead
Copper
AreaC
Lead
Copper
AreaE
Lead
Copper
AreaF
Lead
Copper
21,000 mg/kg
18,000 mg/kg
140,000 mg/kg
18,000 mg/kg
92,000 mg/kg
74,000 mg/kg
11,000 mg/kg
33,000 mg/kg
610 mg/L
45 mg/L
880 mg/L
12 mg/L
740 mg/L
120 mg/L
390 mg/L
120 mg/L
<0.05mg/L
0.57 mg/L
2.5 mg/L
0.54 mg/L
47.0 mg/L
0.65 mg/L
0.10 mg/L
0.60 mg/L
99
99
99
95
94
99
99
99
needed to determine the effectiveness of
this process for stabilizing PCBs.
The ANS 16.1 test showed that the
teachability index of the treated material
successfully exceeded the Nuclear Regula-
tory Commission (NRC) criteria by several
orders of magnitude for lead and copper.
Because measurable quantities of contami-
nants leached from the solids, however,
information about leaching fluxes from
treated material should be considered with
site-specific groundwater conditions before
applying this technology.
The results of the multiple extraction
procedure showed relatively high concen-
trations of lead in the first extraction from the
treated waste. The mean concentration was
330 mg/L lead. This first extraction used the
same procedure as the extraction proce-
dure toxicity (EP) test. Based on the EP
toxicity test, wastes with lead concentra-
tions exceeding 5.0 mg/L are considered
hazardous. Dilution duetogroundwater may,
however, be considered in decisions re-
garding delisting of a hazardous waste.
Data from later extractions showed much
lower concentrations of lead (mean con-
centrations generally less than 1 mg/L),
although the mean concentration increased
to 4.3 mg/L in the last extractions.
Chemical Testing
Table 5 summarizes the results of
chemical and physical tests on both the
untreated and treated wastes. After treat-
ment, the pH of the raw waste, 6.6, in-
creased to 11.5 because of the highly
alkaline reagents used in treatment. The
treated material was so alkaline that adding
acetic acid as part of the TCLP procedure
did not lower the pH more than a few tenths
of a unit.
Oxidation/reduction potential of the
treated waste was less than that of the
untreated material. Electrical conductivity
was significantly higher in the treated wastes,
indicating that ions leached from the treated
material. This increase may not be a con-
cern, however, depending on the nature of
the ions.
The PCB extraction data showed evi-
dence of partial dechlorinatbn of PCBs.
The analysis indicated that heavily chlori-
nated PCB molecules lost one or more
chlorine atoms during the treatment pro-
cess. The phenomenon, however, may not
be due to the solidification/stabilization pro-
cess, because no byproducts of complete
dechlorination were found in the treated
matrix. Therefore, no conclusions regard-
ing the effectiveness of the treatment pro-
cess in dechlorinating PCBs can be drawn.
The air monitoring data suggested that
there was no significant volatilization of
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PCBs during the treatment operations at
the site; however, it should be noted that the
wet, cool weather during the demonstration
did not promote volatilization.
Physical Tests
Table 5 also summarizes the results of
the physical tests performed on the treated
wastes. Weight toss during wet/dry and
freeze/thaw cycle testing was less than 1%.
These data indicated durability in an ex-
posed environment. Unconfined compres-
sive strength (UCS) values ranged from 27
psi to 307 psi. The EPA guidance for land
disposal suggests a minimum UCS of 50 psi
for land disposal of solidified/stabilized
wastes. The hydraulic conductivity of the
treated material was in the range of 10* cm/
sec to 10~7 cm/sec. Hydraulic conductivity
values should be compared with in-situ per-
meability measurements to determine if the
treated material is less conductive than the
material into which it will be placed. Such
in-srtu permeability measurements were not
available from the PESO site because the
rocky nature of the soil made it impossible to
insert the equipment necessary to obtain
in-situ measurements.
An analysis using the specific gravity,
bulk density, and moisture content of the
treated material yielded a calculated poros-
ity of 32% to 50%.
Finally, an analysis using the mass of
material (before and after treatment) and
the bulk density (before and after treatment)
yielded a calculated volume expansion of
20% to 50% with treatment, which means
the volume of the treated material was 20%
to 50% greater than the volume of the
excavated material. It should be noted that
the volume of the excavated material is
likely to be more than the volume of the
material in-srtu. Thus, the total volume ex-
pansion from in-situ volume is likely to be
more than 20% to 50%.
Costs
The cost of this treatment process is $40
to $80 per ton of raw waste treated, based
on the cost information for treatment sup-
plied by Chemfix and the materials-handling
costs experienced during the SITE demon-
stration. This cost does not include the cost
of site preparation, equipment transporta-
tion to and from the site, and final placement
or disposal of the product. Note, also, that
the cost of the process depends heavily on
the processing rate.
Table 5. Physical and Chemical Properties of Treated and Untreated Wastes From Area C of
Chemfix Demonstration
Property
Untreated Wastes Treated Wastes
Eh (millivolts)
Conductivity (\nmhos/cm)
pH
26-day unconfined compressive
290
130
6.6
N/A
24
3,200
11. 3 to 11. 5
27 to 307
strength (psi)
Wet/dry stress weight loss
Freeze/thaw stress weight loss
Hydraulic conductivity (cm/sec)
N/A
N/A
10* to 1&'
1O' to
Conclusions
More than 65% of the treated waste
samples from the Chemfix solidification/
stabilization process metthe TCLP leachate
levels established for the demonstration.
Reductions in teachable lead, as measured
by the TCLP test, ranged from 94% to 99%.
Data from the ANS 16.1 test successfully
exceeded the NRC criteria by several or-
ders of magnitude. Because the treated
material leached measurable quantities of
lead, however, the information from the
ANS 16.1 and other leaching and extraction
tests may be considered with she-specific
groundwater conditions before applying this
technology to a specific site.
The Chemfix process generally produced
treated material with acceptable physical
properties. The treated material had prop-
erties that indicated long-term durability in
exposed environments. Volume increases
in the excavated material ranged from 20%
to 50%.
•&U. S. GOVERNMENT PRINTING OFFICE: 1991/548-028/20164
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The EPA Project Manager, Ed Barth, is with the Risk Reductbn Engineering Laboratory,
Cincinnati, OH 45268 (see below).
The complete report consists of two volumes, entitled "Technology Evaluation Report:
Chemfix Technologies, Inc., Solidification/Stabilizatfon Process, Clackamas, Oregon."
"Volume I" (Order No. PB 91-127696; Cost: $23.00, subject to change) discusses the
results of the SITE demonstration.
"Volume II"(Order No. PB 90-274127, Cost: $45.00, subject to change) contains the
sampling and analytical data and the quality assurance data.
Both volumes of this report will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
A related report, entitled "Applications Analysis Report: CHEMFIX Solidification/Stabiliza-
tion Process," which discusses application and costs, is under development.
The EPA Project Manager can be contacted at:
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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