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SOLIDIFICATION


This profile provides the following general information about this
treatment process:

1.   Description
2.   Applicability
3.   Limitations
4.   Availability and vendor list
5.   Performance data and field applications
6.   Sources of information for this profile



1.   Description:        

IN-SITU SOLIDIFICATION
Solidification/stabilization (S/S) reduces the mobility of
hazardous substances and contaminants in the environment through
both physical and chemical means.  Unlike other remedial
technologies, S/S seeks to trap or immobilize contaminants within
their "host" medium (i.e., the soil, sand,and/or building
materials that contain them), instead of removing them through
chemical or physical treatment.  Leachability testing is typically
performed to measure the immobilization of contaminants.  In situ
S/S techniques use auger/caisson systems and injector head systems
to apply S/S agents to in situ soils.

S/S techniques can be used alone or combined with other treatment
and disposal methods to yield a product or material suitable for
land disposal or, in other cases, that can be applied to
beneficial use.  These techniques have been used as both final and
interim remedial measures.

EX-SITU SOLIDIFICATION
As for in situ solidification/stabilization (S/S), ex situ S/S
contaminants are physically bound or enclosed within a stabilized
mass (solidification), or chemical reactions are induced between
the stabilizing agent and contaminants to reduce their mobility
(stabilization).  Ex situ S/S, however, typically requires
disposal of the resultant materials.



2.   APPLICABILITY: 
     
The target contaminant group for in situ S/S is inorganics
(including radionuclides).  The technology has limited
effectiveness against SVOCs and pesticides and no expected
effectiveness against VOCs; however, systems designed to be more
effective in treating organics are being developed and
tested. 



3.    LIMITATIONS: 
          
Factors that may limit the applicability and effectiveness of
IN-SITU SOLIDIFICATION include: 

1.  Depth of contaminants may limit some types of application
processes.

2.  Future usage of the site may "weather" the materials and
affect ability to maintain immobilization of contaminants.

3.  Some processes result in a significant increase in volume (up
to double the original volume).

4.  Certain wastes are incompatible with variations of this
process. 

5.  Treatability studies are generally required.

6.  Reagent delivery and effective mixing are more difficult than
for ex situ applications.

7.  Like all in situ treatments, confirmatory sampling can be more
difficult than for ex situ treatments.

Factors that may limit the applicability and effectiveness of
EX-SITU SOLIDIFICATION include:

1.  Environmental conditions may affect the long-term
immobilization of contaminants.

2.  Some processes result in a significant increase in volume (up
to double the original volume).

3.  Certain wastes are incompatible with different processes.
Treatability studies are generally required.

4.  VOCs are generally not immobilized. 

5.  Long-term effectiveness has not been demonstrated for many
contaminant/ process combinations.



4.   AVAILABILITY AND VENDOR LIST

Solidification is commercially availabile from a number of
vendors, listed below:

Advanced Remediation Mixing                  (504) 461-0466
Chemfix Technologies, Inc.                   (504) 461-0466
Funderburk & Associates                      (903) 545-2004
International Waste Technologies             (316) 269-2660
Geo-Con, Inc.                                (412) 856-7700
Hazco
Separation and Recovery Systems, Inc.        (714) 261-8860
Silicate Technology Corporation              (602) 948-7100
S.M.W. Seiko, Inc.                           (510) 783-4105
Soliditech, Inc.                             (713) 497-8558
STC Omega                                    (602) 948-7100
VFL
WASTECH, Inc.                                (615) 483-6515
Wheelabrator Technologies, Inc.              (603) 929-3000



5.   PERFORMANCE DATA AND FIELD APPLICATIONS
          
S/S technologies are well demonstrated, can be applied to the most
common site and waste types, require conventional materials
handling equipment, and are available competitively from a number
of vendors.  Most reagents and additives are also widely available
and relatively inexpensive industrial commodities. 

In situ S/S processes have demonstrated the capability to reduce
the mobility of contaminated waste by greater than 95%.The
effects, over the long term, of weathering (e.g., freeze-thaw
cycles, acid precipitation, and wind erosion), groundwater
infiltration, and physical disturbance associated with
uncontrolled future land use can significantly affect the
integrity of the stabilized mass and contaminant mobility in ways
that cannot be predicted by laboratory tests.  Depending upon the
original contaminants and the chemical reactions that take place
in the ex situ S/S process, the resultant stabilized mass may have
to be handled as a hazardous waste.  For certain types of
radioactive waste, the stabilized product must be capable of
meeting stringent waste form requirements for disposal (e.g.,
Class B or Class C low level materials).  Remediation of a site
consisting of 18,200 metric tons (20,000 tons) could require less
than 1 month, depending on equipment size and type and soil
properties (e.g., percent solids and particle size).

DOE has demonstrated the Polyethylene Encapsulation of
Radionuclides and Heavy Metals (PERM) process at the bench scale. 
The process is a waste treatment and stabilization technology for
high-level mixed waste.  Specific targeted contaminants include
radionuclides (e.g., cesium, strontium, and cobalt), and toxic
metals (e.g., chromium, lead, and cadmium).  The process should be
ready for implementation in FY95.



6.   Source: 

Marks, Peter J., Walter J. Wujcik and Amy F. Loncar, October 1994.
REMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE,
SECOND EDITION.  DOD Environmental Technology Transfer Committee.
NTIS No. PB95-104782.  Reproduced for the Bloomington, Indiana PCB
Superfund Sites Bulletin Board with the permission of USAEC, 
SFIM-AEC-ETD, APG, MD. Supplemented by MVA Consulting, Inc.
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