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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