vvEPA
United States
Environmental Protection
Agency
EPA/540/M5-89/011
October 1989
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
Solidification/Stabilization Process
Chemfix Technologies, Inc.
TECHNOLOGY DESCRIPTION:The Chemfix tech-
nology is a patented solidification/stabilization process
for treating hazardous wastes. Proprietary reagent
additives may include soluble silicates and silicate-
setting materials. The process is designed as a
continuous operation capable of treating large
quantities of wastes rapidly. The products of the
process are intended to be stable, friable materials
with good erosion resistance and low permeabilities.
In addition, the process is intended to treat the
material without a large increase in volume.
After the contaminated material is excavated and
screened to remove pieces larger than 1 inch, a
conveyer belt moves it from the feed hopper to the
weight feeder, where it is measured. The homog-
enizer mixes the wastes with water to achieve the
desired moisture content. The wetted material then
moves to a Chemfix-designed pug mill, where it is
blended with the proprietary reagents. After the
material is thoroughly mixed, it is discharged and
allowed to harden. The final product is a solidified
mass.
WASTE APPLICABILITY: This process is designed to
treat soils, sludges, and waste waters. It has been
used for a variety of industrial wastes contaminated
with heavy metals and organic compounds with high
molecular weight.
Hopp«r With Ev»n F**d*r
Conv«yor
WMcr Supply
frf rtqulrad)
Ajarmtand Control
Pan* No. 1
Chut* to Truck Loading Area
Figure 1. High solids handling system block process flow diagram.
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DEMONSTRATION RESULTS: EPA and the devel-
oper demonstrated this solidification/stabilization
process at the Portable Equipment Salvage Company
site in Clackamas, Oregon during March, 1989. The
site had been used for the scrapping and recycling of
transformers and metal equipment. Although the soil
at the site is contaminated with a variety of pollutants,
the contaminants of concern for this demonstration
were lead, copper, and PCBs because they were
found in the highest concentrations in the preliminary
round of sampling. The equipment utilized was
capable of processing soils at a rate of up to 100 tons
per hour.
Several leaching and extraction tests were conducted
on products of the solidification/stabilization process to
indicate the long-term stability of the processed
material.
The toxicity characteristic leaching procedure (TCLP)
extracts from processed wastes contained lead in
concentrations 94 to 99 percent less than in leachate
extracts of untreated wastes. Table 1 presents a
summary of the results of the TCLP tests for lead and
copper.
No conclusions could be derived regarding PCB
immobilization since the concentrations of PCB in the
initial TCLP extracts were extremely low. PCB extrac-
tion data does show evidence of partial dechlorination
of the PCBs. However, the phenomenon may not be
due to the solidification/stabilization process only.
The wet/dry and freeze/thaw durability tests were very
good, showing little or no weight loss after 12 cycles.
The unconfined compressive strength (UCS) at 28
days ranged from 27 to 307 psi. Permeability of the
treated material ranged between 1x10-6 cm/sec and
6.4 x 10'7 cm/sec. Table 2 presents a summary of
these results of the physical tests and other chemical
tests.
Other results of the demonstration include the
following:
• The volume increase in the excavated waste
material after treatment ranged from 20 to 50
percent.
The air monitoring data suggest that there was
significant volatilization of PCBs during
treatment process.
no
the
A Demonstration Report describing the complete
demonstration will be complete in early 1990.
FOR FURTHER INFORMATION:
EPA Project Manager
Ed Barth
U.S. EPA
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7669 (FTS: 684-7669)
Table 1.
Mean Concentrations of Concern from Chemfix
Demonstration
Area A
Lead
Copper
AreaC
Lead
Copper
Area E
Lead
Copper
Area F
Lead
Copper
Untreated
Waste
(Total)
21 ,000 mg/kg
18,000 mg/kg
140,000 mg/kg
18,000 mg/kg
92,000 mg/kg
74,000 mg/kg
1 1 ,000 mg/kg
33,000 mg/kg
TCLP From
Untreated
Waste
610 mg/L
45 mg/L
880 mg/L
12 mg/L
740 mg/L
120 mg/L
390 mg/L
120 mg/L
TCLP From
Treated
Waste
< .05 mg/L
0.57 mg/L
2.5 mg/L
0.54 mg/L
47 mg/L
0.65 mg/L
0.10 mg/L
0.60 mg/L
Percent
Reduction
of TCLP
Extractable
Metal
99
99
99
95
94
99
99
99
Table 2. Physical and Chemical Properties of
Treated and Untreated Wastes from
Area C of Chemifx Demonstration
AreaC
Eh (millivolts)
Conductivity (umhos/cm)
PH
28 -day UCS (psi)
Wet/dry stress weight loss
Freeze/thaw stress weight
loss
Permeability (cm/sec)
Untreated
Wastes
290
130
6.6
N/A
N/A
N/A
10-4 to 10-«
Treated
Wastes
24
3200
11.3-11.5
27-307
<1%
<1%
10-6 tO TO'7
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