P/EPA
           United States
           Environmental Protection
           Agency
            Research and
            Development
            (RD 681)
EPA/540/A5-89/004
August 1990
International Waste
Technologies/Geo-Con In Situ
Stabilization/Solidification

Applications Analysis Report
                 SUPERFUND INNOVATIVE
                 TECHNOLOGY EVALUATION

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                                     EPA/540/A5-89/004
                                        August 1990
International Waste Technologies/
           Geo-Con In Situ
      Stabilization/Solidification

     Applications Analysis Report
         Risk Reduction Engineering Laboratory
          Office of Research and Development
         U.S. Environmental Protection Agency
               Cincinnati, OH 45268

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                                  Notice
The information in  this document  has  been funded by the U.S. Environmental
Protection Agency under Contract No. 68-03-3255 and the Superfund Innovative
Technology Evaluation (SITE) Program.  It has been subjected to the Agency's peer
review and administrative  review and it has been approved for publication as a
USEPA document. Mention of trade names or commercial products does not constitute
an endorsement or recommendation for use
                                    11

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                                       Foreword
      The Superfund Innovative Technology Evaluation (SITE) program was authorized in
      the 1986 Superfund amendments. The program is a joint effort between EPA's Office of
      Research and Development and Office of Solid Waste and Emergency Response. The
      purpose of the program is to assist the development of hazardous-waste treatment
      technologies that will be necessary to meet new cleanup standards, which  require
      greater reliance on permanent remedies.  This is accomplished through technology
      demonstrations that are designed to provide engineering and cost  data on selected
      technologies.

      This project  consists of an analysis of the International Waste Technologies/Geo-Con
      proprietary in situ stabilization/solidification process and represents the sixth field
      demonstration in the SITE program. The technology demonstration took place at a
      former electric service shop owned by General Electric Company in Hialeah, Fla. The
      demonstration effort was directed at obtaining information on  the performance and
      cost of the process for use in assessments at other sites. Documentation will consist of
      two reports.  The Demonstration Report describes the field activities and laboratory
      results and has been previously issued. This Applications Analysis Report provides an
      interpretation of the available data and presents conclusions on  the  results and
      potential applicability of the technology.

      Additional copies of this report may be obtained at no charge from EPA's Center for
      Environmental Research Information, 26 West Martin Luther King Drive, Cincinnati,
      Ohio, 45268, using the EPA document number found on the report's front cover. Once
      this supply is exhausted, copies can be  purchased from the National Technical
      Information  Service, Ravensworth Bldg., Springfield,  VA, 22161,  703-487-4600.
      Reference copies will  be available at EPA libraries in their  Hazardous Waste
      Collection. You can also call the SITE Clearinghouse hotline at 1-800-424-9346 or 202-
      382-3000 in Washington, D.C. to inquire about the availability of other reports.
Walter W.  Kovalick,  Jr.,
Acting Director,  Technology
    Innovation Office
Alfred
Acting -DTfector,  Office  of Engineering
    and Technology Demonstration

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                                  Abstract
An evaluation was performed of the International Waste Technologies (IWT) HWT-20
additive and the Geo-Con, Inc. deep-soil-mixing equipment for an  in  situ
stabilization/solidification process and its applicability as an on-site treatment method
for waste site cleanup. The analysis of this technology is contained in two reports, the
Technology Evaluation which describes the demonstration and this Applications
Analysis which evaluates the technology based upon all available data.

A demonstration was held at a General Electric Co. electric service shop in Hialeah,
Florida, which provided the bulk of the information for the technology evaluation.
Operational  data and sampling and  analysis information, for this  first field
application of the IWT additive, were carefully monitored and controlled to establish a
database against which other available IWT and Geo-Con data, and their claims for
their technologies, could be compared and evaluated. Conclusions  were  reached
concerning the technology's suitability for use in  cleanups of various contaminants
and at different locations.

The  technical criteria used to evaluate the effectiveness of the in situ process were
contaminant  mobility (based on leaching and permeability tests), and the potential
long-term integrity of  the solidified soils  (based on some physical tests and
microstructural studies). The Geo-Con deep-soil-mixing system was also evaluated.

Since the most controlled sampling on the IWT additive was performed during the
demonstration, much of the emphasis of the evaluation is based upon this data. Test
samples were taken of the site material before treatment to characterize.the site and of
the solidified materials after curing  for 5  weeks.  Samples of treated  and untreated
material were analyzed to determine: physical  properties (such as unconfined
compressive strength and permeability) that along with the microstructural studies
provides clues to long-term durability of the treated mass; chemical properties (such as
soil composition and leachability) that provide information on contaminant mobility.

This report  evaluates the  in situ process (based on  the test results of the
demonstration), other data provided  by the technology developers, and the general
capabilities of cement-based systems.  It also discusses the probable applicability of the
technology to sites other than the GE electric service shop.
                                      IV

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                         Abstract (Continued)

The conclusions drawn from, the available data are that:  (1) immobilization of
polychlormated biphenyls (PCBs) appears  likely, although due to low leachate
concentrations for  both the treated and  untreated  soils - a result of the low
concentrations of PCBs in the soil encountered in most of the tests  - it cannot  be
confirmed; (2) heavy metals can probably be immobilized; (3) volatile organics can
bereduced to low concentrations in treated soil leachates, but the ability to immobilize
is not clear; (4) a small volume increase on the order of magnitude of 5%-10% can  be
expected; (5) the solidified material shows satisfactory physical properties- - with high
unconfined compressive strengths, moderately  low permeabilities, and satisfactory
integrity for the wet/dry samples - but unsatisfactory integrity for the freeze/thaw
samples; and (6) microstructural results show  a dense, low-porosity  homogeneous
mass - indicating a potential for long-term durability.

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                                  Contents
                                                                        Page
Foreword 	  iii
Abstract 	  iv
Tables  	  ix
Figures  	   x
Abbreviations and Symbols 	  xi
Conversions  	  xiv
Acknowledgments 	„....-	   xv

1. Executive Summary  	   1
      Conclusions	   1
      Results  	   2
2. Introduction	   5
      The SITE Program	   5
      SITE Program Reports  	   5
      Overview of Stabilization/Solidification 	   6
      Stabilization/Solidification Technologies and Superfund Reponse Actions     6
      Key Contacts  	   8
3. Technology Applications Analysis 	   9
      Introduction 	   9
      Conclusions 	   9
      Evaluation of Performance	   10
      Environmental Regulations Pertinent to In Situ Stabilization/
        Solidification	   16
      Waste Characteristics and Their Impact on Performance of
        the Technology	20
      Material Handling Required by the Demonstrated Technology  	    22
      Personnel Issues  	   22
      Procedures for Evaluating Stabilization/Solidification  	    22
4. Economic Analysis  	   25
      Introduction 	   25
      Results of Economic Analysis  	   25
      Basis of Economic Analysis	   26
                                     vn

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                       Contents  (Continued)
References 	  31
Appendices
     A. Process Description  	  33
     B. Vendor's Claims for the Technology 	  37
     C. SITE Demonstration Test Results  	  53
     D. Case Studies  	  63
References for Appendices 	  75
                                   Vlll

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Tables
Number
   1

   2
  B-l
  B-2
  C-l
  C-2
  C-3
  C-4
  C-5
  C-6
  C-7
  C-8
  C-9
Posttreatment Soil and Leachate Analyses of Samples
  CollectedbyGE ......... ....
Estimated Cost
Infrared Data
DSC Data  . .
Physical Properties of Untreated Soils - Sector B
Physical Properties of Untreated Soils - Sector C  ......... ,
Physical Properties of Treated Soils - Sector B
Physical Properties of Treated Soils - Sector C
Results of Formulation Studies
PCBs in Soils and Leachates - Sector B  . .
PCBs in Soils and Leachates - Sector C
Total Volatile Organics in Soils and Leachates
Total of Four Priority Pollutant Metals in Soils and Leachates
                                     Page

                                      12
                                      26
                                      51
                                      51
                                      56
                                      57
                                      58
                                      59
                                      59
                                      60
                                      61
                                      62
                                      62

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                                 Figures
Number                                                            Page
   A-l    Batch Mixing Plant	  34
   A-2    Overlapping Column Arrangement 	  35
   B-l    Coordination Complexes  	  40
   B-2    Pn to dn Bonding 	  40
   B-3    Lewis Acid Base Reactions: Formation of Sigma Bonds  	  41
   B-4    Observed Bonding Phenomenon in the HWT-23
            Treatment Matrix	  42
   B-5    Formation of Permanent Sigma and Pi Bonding
            (Covalent Bonding)  	  43
   B-6    Supramolecular Chemistry/Multiple and Secondary Bonding	  44

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                     Abbreviations  and Symbols
 ANS 16.1
 ARARS
 ASTM
 BOAT
 CERCLA

 CFR
 cm/s
 DSC
 DSM
 EPA
 EPTox
 °F
 FTIR
 ft3
 FY
 F006
 F012

 F019

 g/ml
 GC/ECD
 GC/MS
Geo-Con
GE
gpm
 Modified American Nuclear Industry Leaching Test Methods
 Applicable or Relevant and Appropriate Requirements
 American Society for. Testing and Materials
 Best Demonstrated Available Technology
 Comprehensive  Environmental Response, Compensation  and
 Liability Act of 1980
 Code of Federal Regulations
 centimeters per second — permeability units
 differential scanning calorimetry
 deep soil mixing
 Environmental Protection Agency
 Extraction Procedure Toxicity Test
 degrees Fahrenheit
 Fourier transform infrared
 cubic feet
 fiscal year
 wastewater treatment sludges from electroplating operations
 quenching waste water-treatment sludges from metal heat-treating
 operations where  cyanides are used
 wastewater treatment sludges from the chemical conversion
 coating of aluminum
 grams per milliliter
 Gas chromatography/electron capture detector
 Gas chromatography/mass spectrometry
 Geo-Con, Inc.
General Electric Company
gallons per minute
                                    XI

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            Abbreviations and Symbols (Continued)
HSWA
HWT-20
IWT
kW
kWh
Ib/min
LDR
LE
MCC-1P
mg/kg
mg/L
NCP
NPL
O&G
ORD
OSHA
OSWER
PCBs
PCP
PSD
ppb
ppm
psi
RCRA
ROD
RREL
SARA
SEM
Hazardous and Solid Waste Amendments to RCRA -1984
Treatment additive offered by IWT
International Waste Technologies
Kilowatt(s)
Kilowatt hour
pounds per minute
Land Disposal Restriction
Law Environmental, Inc.
Materials Characterization Center Static Leach Test Method
milligrams per kilogram
milligrams per liter
National Contingency Plan
National Priorities List
oil and grease
Office of Research and Development
Occupational Safety and Health Act
Office of Solid Waste and Emergency Response
polychlorinated biphenyls
pentachlorophenol
particle size distribution
parts per billion
parts per million
pounds per square inch
Resource Conservation and Recovery Act
Record of Decision
Risk Reduction Engineering Laboratory
Superfund Amendments and Reauthorization Act of 1986
scanning electron microscope
                                    Xll

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            Abbreviations and Symbols (Continued)

SITE            Superfund Innovative Technology Evaluation Program
TCLP           Toxicity Characteristic Leaching Procedure
TMSWC         Test Methods for Solidified Waste Characterization
TOG            total organic carbon
TSCA           Toxic Substances Control Act
UCS            unconfined compressive strength
um             micrometer
ug/L            micrograms per liter
VOC            volatile organic compound
XRD            X-ray diffraction
yd3             cubic yard
                                  Kill

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                               Conversions
                   English (US)

Area:               1 ft2

                   lin2

Flow Rate:          1 gal/min

                   1 gal/min

                   1 Mgal/d

                   1 Mgal/d

                   1 Mgal/d

Length:            1 ft

                   lin

                   lyd

Mass:              1 Ib

                   lib

Volume:           1 ft3

                   1ft3

                   Igal

                   Igal

ft = foot, ft2 = square foot, ft3  = cubic foot
in = inch, in2 = square inch
yd = yard
Ib = pound
gal = gallon
gal/min = gallons per minute
Mgal/d = million gallons per day
m = meter, m2 = square meter, m3 = cubic meter
cm = centimeter, cm2 = square centimeter
L = liter
g = gram
kg = kilogram
m3/s = cubic meters per second
L/s = liters/second
m3/d = cubic meters per day
Metric (SI)

9.2903 x 10-3 m2

6.4516 cm2

6.3090 x 10-5 m3/s

6.3090 x 10-2 L/S

43.8126 L/s

3.7854 x!03m3/d

4.3813 x 10-2 m3/s

0.3048 m

2.54cm

0.9144m

4.5359 xlO-2g

0.4536 kg

28.3168 L

2.8317 x lO-2 m3

3.7854 L

3.7854 x 10-3 m3
                                     xiv

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                           Acknowledgments
This report was prepared under the direction and coordination of Mary Stinson EPA
SITE Project Manager in the Risk Reduction Engineering Laboratory, Cincinnati
Ohio. Contributors and reviewers for this report were the USEPA's Office of Research
and Development; Linda D. Fiedler of the Office of Solid Waste and Emergency
Response; Gregory A. Ondich of the Office of Environmental  Engineering and
Technology Demonstration; Jeffrey Newton of International Waste Technologies-
Brian Jasperse of Geo-Con, Inc.; John Harrsen of General Electric Co • Walter
Sumansky of NUS Corp.;  and Frank Cartledge, Harvill Eaton, and Marty Tittlebaum
ot bcientific Waste Strategies, Inc.
    iN      WaS PrePared for EPA'S Superfund Innovative Technology Evaluation
(bITE) Program by Stephen Sawyer of Foster Wheeler Enviresponse, Inc., for the U S
Environmental Protection Agency under Contract No. 68-03-3255.
                                   xv

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                                          Section 1
                                    Executive Summary
Introduction
In 1986,  the  EPA established  the Superfund
Innovative Technology Evaluation (SITE)  Program
to promote the development and use of innovative
technologies  to clean up Superfund  sites.  The
analysis of the  technologies in the SITE Program are
contained in  two documents, the Technology
Evaluation Report and this Applications Analysis
Report. This report evaluates  and  estimates the
applicability and costs of the  International Waste
Technologies (IWT)/Geo-Con in  situ  stabili-
zation/solidification process based on all available
data. This data, other than the demonstration,  is
from laboratory studies.

The  most extensive testing  of the  combined
technologies  was performed  during  the SITE
demonstration,   based  upon an agreed to
demonstration  plan between  EPA  and  the
developers, although other  information on the
individual  technologies  is provided  by  the
developers. EPA used a direct approach to evaluate
the technology by measuring contaminant mobility
and solidified mass durability. The emphasis of the
IWT research work has been to show that chemical
bonding of additive to contaminant occurs. However,
this is  only an indirect approach, and it requires a
research program that is outside  the scope of a SITE
project.

The demonstration occurred at a General Electric
Co. (GE) electric service shop in Hialeah, Florida in
April 1988. The process involves the in situ injection
and mixing of  the IWT additive HWT-20 with the
hazardous waste material. IWT claims that HWT-20
chemically bonds  to the PCB contaminants, thus
immobilizing them and containing them within a
hardened, leach-resistant concrete-like mass.
Therefore, the  major objectives of the SITE project
were to  evaluate the  IWT/Geo-Con  in situ
stabilization/solidification  technology in  the
following areas:
   •  Immobilization  of polychlorinated biphenyls
     (PCBs)  - mainly Aroclor  1260, a  set  of
     congeners of known ratio.

   •  Immobilization  of organic and heavy metal
     contaminants, based on other experience of the
     developers.

   •  Demonstration of in situ operation of the Geo-
     Con soil mixing equipment.

   •  Degree of soil consolidation (solidification)
     caused by the chemical additive, HWT-20.

   •  Probable long-term stability and  integrity  of
     the solidified soil.

   •  Performance and  reliability  of the Geo-Con
     injection and mixing auger.

   •  Costs for commercial-scale applications.

Conclusions

The conclusions drawn from reviewing the data on
this in situ stabilization/solidification process, both
from the SITE demonstration and  other available
data in relation to SITE project objectives were:

   •  PCBs  do appear to be immobilized by the
     process. However, for most of the tests, the PCB
     concentrations  in the soil  and resulting
     leachate concentrations were low and so close to
     the  analytical detection limits that a firm,
     decisive evaluation of the technology's ability to
     immobilize PCBs could not be performed.

   •  From  laboratory studies provided by IWT,
     immobilization  of volatile and semi-volatile
     organics  may occur in some instances. This  is
     based  on  TCLP  leach tests, see  Appendix  D
     Case study D-4.  In addition, the IWT additive
     contains  organophilic clays, which are known

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  in some cases to bond to organics. However,
  since insufficient data exists, both from the
  demonstration and  these laboratory studies,
  confirmation of immobilization is not possible.

• IWT data indicates  that the HWT compounds
  probably immobilize heavy metals. This is
  supported by the fact that most cement-based
  systems can immobilize metals.

• The PCB concentrations  in the soil at the
  Hialeah site were too low for effective
  evaluation of this technology. Thus, bench scale
  testing of  samples by EPA with higher
  concentrations of PCBs would  have enhanced
  the evaluation of the IWT additive. Later, such
  treatability studies were added to the SITE
  demonstrations.

• The physical properties of the treated soils were
  in general  quite satisfactory, which would
  support the  potential for long-term durability.
  High unconfined compressive strengths (UCS)
  (300-1,000 psi), low permeabilities (10-6 to 10-7
  cm/s), and satisfactory  results of the wet/dry
  weathering  tests were obtained. Many of the
  freeze/thaw test specimens showed large weight
  losses and samples degraded sharply. However,
  IWT has indicated that the additive mixture
  used  in the demonstration was designed for
  Florida, where freeze/thaw weathering should
  not be a problem. The volume increase of the
  soil after treatment was small, about 8.5% in
  the  demonstration.  The microstructural
  analyses of solidified soil samples indicated a
  potential for long-term durability; the samples
  showed a dense, homogeneous, and low-porosity
  structure. The apparent disagreement between
  the poor freeze/thaw results (taken only during
  the demonstration)  and the other satisfactory
  results cannot be explained at this time.

• The Geo-Con deep-soil-mixing equipment
  appeared  to  work  well   during   the
  demonstration and provided intimate mixing of
  additive and soil.  Geo-Con also has other
  experience  at hazardous waste sites, where
  sludge ponds were solidified and barrier  walls
  provided,  as well as  considerable soil
  consolidation experience in all types of  soils.
  Thus, the deep-soil-mixing capabilities of Geo-
  Con are well proven.

• The  IWT/Geo-Con  in  situ  stabiliza-
  tion/solidification system is  economical.
  Remediation costs for two cases were estimated.
  For the first case, using Geo-Con's larger 4-
  auger system, under the ground rules defined in
  Section 4, the cost was $lll/ton of soil. For the
     1-auger unit, used during the demonstration,
     the cost was $194/ton of soil.

It  appears possible to apply the IWT/Geo-Con
technology for immobilization of heavy metals, PCBs
and some heavy organics in  wastes up to 25 wt%
organics. Although an HWT-20 admix was selected
for use at the Hialeah site for the treatment of PCB-
contaminated soils, other formulations exist to treat
other contaminants. However, since  very limited
bench-scale studies  have been  performed, it  is
recommended that treatability studies — site specific
leaching, permeability, and physical tests — be
performed on each specific waste to be treated.

The Geo-Con technology can be used for most soils in
most climates with treatment capabilities to a depth
in excess of 100 ft. However, clays,  oily sands, and
cohesive soils may reduce auger penetration rate and
depth of operation.

Potential physical limitations in  the application of
the IWT/Geo-Con technology  need to be considered.
The volume increase may cause some difficulties in
restricted site areas where land contours could be
seriously altered.  An  additional  limitation  is the
technology's use in cold climates, where freeze/thaw
degradation of the solidified monolith may occur and
the feed slurry may freeze during operation. Large
rocks (> 10 in.) and man-made obstacles such  as
drums and lumber can provide hindrances.

Results

Chemical Tests

Chemical analyses were performed on untreated and
treated soils, along with leaching tests for the
corresponding soil sample. Leachate analyses exist:
on treated  and  untreated soils  from  the
demonstration,  using the Toxicity Characteristic
Leaching Procedure (TCLP); on Law Environmental
(LE) samples taken at the GE site, using Extraction
Procedure Toxicity (EP Tox) and TCLP; and from
some testing performed by IWT on PCBs,  VOCs,
heavy metals, and semivolatile organics, using
TCLP.

The  IWT  process,  as  evaluated  during the
demonstration, appears to immobilize  PCBs.
However, due to the relatively low levels of PCBs at
the  Hialeah site,  which  produced  leachate
concentrations close to their detection limits (0.1
ug/L),  more  information at  higher  PCB
concentrations are  required  to confirm this
conclusion. For  laboratory prepared samples by LE
using soils from the site known  to have different
concentration levels of PCBs, which ranged from 83
to 5,628 mg/kg, results from EP  Tox tests showed
immobilization. However, TCLP tests on 5 samples

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showed higher concentrations in the leachates of
treated soils than those of untreated soils. LE had no
definitive explanation for the unexpected  results.
Thus, the LE results also provide some uncertainty
on the ability of the process to immobilize PCBs.

The demonstration was inconclusive on the ability of
the process to  immobilize VOCs and metals, due to
an  insufficient number of  samples  available for
testing. In addition, IWT did not tailor its HWT-20
additive  to immobilize VOCs and metals,  but did
design it for PCBs. IWT has performed some TCLP,
tests on treated samples prepared in the laboratory,
and considerable  laboratory testing  using solvent
extraction, Fourier transform infrared (FTIR) and
differential scanningcalorimetry (DSC). These latter
tests  were to  prove  that the additive chemically
bonds to various organic and inorganic compounds. It
does appear that some bonding occurs, which would
in all likelihood reduce contaminant mobility.
Chemical bonding should also reduce the need for
maintaining physical integrity  of the solidified
monolith.

Physical Tests

The most extensive physical testing carried out to
date on the IWT process was performed as part of the
SITE  demonstration, although some additional  data
was obtained  by LE [1] for GE on laboratory
prepared samples and from core samples taken
shortly after  the demonstration [2]. All of the
available test data are based on a soil with a very low
organic  content, i.e., a very  narrow range of
contaminated soils. IWT cannot provide any other
data;  their research  emphasis is related  almost
exclusively to chemical bonding studies, which  they
claim show the capabilities of their additives better
than physical tests.

During the demonstration, unconfined compressive
strength  (UCS) values ranged from a low of 75 psi in
Sector B  to a high of 866 psi in Sector C, with the
overall average about 400 psi. The tests performed
by LE produced UCS values ranging from 198 to
2,127 psi for approximately the same dosage rate of
HWT-20. These are very satisfactory when compared
to the EPA guideline of a 50-psi  minimum [3] for
stabilization/solidification systems and other
concrete-based waste-treatment systems, which have
UCS results typically in the range of 15 to 150 psi [4].
However, there are a few other technologies that do
provide larger values of UCS. High UCS values
imply the potential for maintaining structural
integrity.

The results from  the 12-cycle wet/dry  and
freeze/thaw weathering tests showed low absolute
weight losses for the wet/dry samples (0.3% to 0.4%).
However, for the freeze/thaw test specimens, weight
losses up to 30% were seen, with an average of 6.3%,
 while the control sample weight losses were about
 0.3%. UCS tests on the weathered samples from the
 SITE demonstration showed no loss of strength when
 weight losses were less than 3.0%. Above 3.0%, very
 severe strength losses were  measured, with  UCS
 values approaching zero at 10% weight loss. These
 weathering tests are more severe  than weathering
 under an actual field environment, but do provide an
 indication of short-term durability, since the tests
 only consist of 12 cycles. IWT has indicated that they
 can adjust the additive mix to be  more resistant to
 freeze/thaw conditions. Quantification of solidified
 mass integrity in  terms of life expectancy is not
 possible.

 Permeability  is a measure of a  solid's  ability to
 permit the passage of water. The treated soil values
 obtained for the SITE demonstration were between
 10-6 and 10-7 cm/s, and they are slightly greater than
 those obtained by LE and EPA on  samples prepared
 by LE. These  values are comparable to the target
 value of lO-7 cm/s or less used for designing soil
 barrier liners for hazardous-waste landfill sites.
 Also, this  is a  large decrease compared  to  the
 untreated  soil (10-2 cm/s) and indicates the
 groundwater will flow around  the treated block. Low
 permeabilities should reduce  the potential for both
 erosion and leaching.

 Bulk density results  were obtained for  the SITE
 demonstration as well as for  some earlier samples
 prepared by LE for GE. The bulk density increase on
 solidification  averaged 21%, from 1.55  g/mL (96
 Ib/ft3) to 1.88 g/mL (117 Ib/ft3),  for a total mass
 increase (HWT-20 plus water)  of 32%, which resulted
 in a volume increase of 8.5%. Even though this
 volume increase is relatively small, the ground rise
 could require removal of treated soil or special site
 contouring. Only posttreatment values are available
 from the LE tests and they tend to agree with the
 demonstration results, showing a bulk density of
 about 1.83 g/mL (114 Ib/ft3).

The microstructual analyses performed on SITE
demonstration samples included optical  and
 scanning electron microscopy  and X-ray diffraction
analyses of the crystalline structures. These results
 showed a dense,  homogeneous,  and nonporous
structure. Therefore, a potential for long-term
durability of the treated soil monolith exists.

Operations

Geo-Con, Inc. performed the remedial operations for
the demonstration in two 10x20-ft test sectors. They
were responsible for  the slurry preparation, flow
control of additive and water,  and soil injection and
mixing.  Equipment operations were  satisfactory.
Some minor operating problems occurred, such as:
inability to maintain automatic feed control; losing
supplemental water for the last 21 soil columns due

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to a leak in the auger head; and the locations of many
of the soil columns deviated from the targeted
location, producing some poorly treated  areas.
However, these difficulties are readily fixable. Geo-
Con also has very considerable experience  in soil
consolidation, constructing slurry barrier liners and
work similar to that at Hialeah in all types of soils to
depths in excess of 100 ft.  Overall, the conclusion is
that Geo-Con's injection  and mixing equipment
provides a unique technology that can be considered
a  valid option  where  in  situ  stabiliza-
tion/solidification or solidification technologies are
deemed desirable.

Economics
The economic  analysis investigated two cases, one
using a 1-auger machine  as in the  demonstration,
and the other with a 4-augef unit, which would be
used for large-scale operations. Only one  additive
rate was assumed, 0.15 Ib HWT-20/lb dry soil, which
is near  the minimum that IWT would use for any
remediation. Most of the operating expenses were
provided by Geo-Con, based on their quotation to GE.

The results, based on a 5 d/wk, 8 h/d operation and
the simplified concepts defined in Section 4, showed
the costs would be $11 I/ton of soil for the 4-auger
unit  and $194/ton of soil for the 1-auger unit. The
cost components with the most impact on the totals
were equipment rental,  the HWT-20 additive, and
labor, which combined, amounted to about 85% of the
total cost.

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                                           Section 2
                                          Introduction
 The SITE Program
 In 1986, the EPA's Office of Solid Waste and
 Emergency Response (OSWER)  and  Office  of
 Research and Development (ORD) established the
 Superfund Innovative Technology Evaluation (SITE)
 Program to promote the  development and use  of
 innovative technologies to clean up Superfund sites
 across the country. The SITE Program is composed of
 two major elements: the  Demonstration Program
 and the Emerging Technologies Program.

 The major focus has been on  the Demonstration
 Program, which is designed to provide engineering
 and cost data on selected technologies. To date, the
 demonstration projects have  not  involved EPA
 funding  for technology developers. EPA and
 developers participating in the  program share the
 cost of the demonstration. Developers are responsible
 for demonstrating  their innovative  systems at
 chosen sites, usually  Superfund sites. EPA  is
 responsible for sampling, analyzing, and evaluating
 all test results. The  result is an assessment of the
 technology's performance, reliability, and  cost. This
 information will be used in conjunction with other
 data to select the most appropriate technologies for
 the cleanup of Superfund sites.

 Developers of innovative technologies  apply  to the
 Demonstration Program by responding  to  EPA's
 annual solicitation. To qualify,for the program,  a
 new technology must be at  the pilot or full  scale and
 offer some advantage over existing technologies.
 Mobile technologies are of particular interest to
 EPA.

 Once EPA has accepted a proposal, EPA and the
 developer work with the EPA regional offices and
 state agencies to identify a site containing  wastes
 suitable for testing the capabilities of the technology.
 EPA prepares a detailed  sampling and analysis plan
 designed to thoroughly evaluate  the technology and
 to ensure that the  resulting data are reliable. The
 duration of a demonstration varies from a few days to
 several months, depending on the length of time and
quantity of waste needed to assess the technology.
After the completion of a technology demonstration,
  EPA prepares two reports, which are explained in
  more detail below. Ultimately, the Demonstration
  Program leads to an analysis of the technology's
  overall applicability to Superfund problems.


  SITE Program Reports
  The analysis  of technologies  participating in  the
  Demonstration Program  is contained  in two
  documents, the Technology Evaluation Report and
  the  Applications   Analysis  Report.  The
  Demonstration  Report contains a comprehensive
  description of the demonstration sponsored by  the
  SITE program and its results.. This report  gives a
  detailed  description of the technology, the site and
  waste used for  the demonstration, sampling and
  analysis  during the test, and the data generated.

  The purpose of the Applications Analysis Report is to
  estimate the  Superfund applications and costs of a
  technology based on all available data. This report
  compiles and summarizes the  results of the  SITE
  demonstration, the vendor's design and test  data,
  and other laboratory and field applications of the
  technology.  It  discusses  the  advantages,
  disadvantages, and limitations of the technology.
  Costs of the technology for different applications are
  estimated based on available data on pilot- and full-
  scale applications. The report discusses the factors,
  such as site and waste characteristics, that have a
  major impact on costs and performance.

  The amount of available data for the evaluation of an
  innovative technology varies widely. Data may be
  limited to laboratory tests on synthetic wastes, or
  may include  performance data on actual wastes
  treated at the pilot or full scale. In addition, there are
  limits to conclusions regarding  Superfund
  applications that can be drawn from a single field
 demonstration. A successful field demonstration does
- not necessarily assure that a technology will  be
 widely applicable or  fully  developed to the
 commercial scale. The Applications  Analysis
 attempts to synthesize  whatever information is
 available and draw reasonable conclusions.  This
 document will be very useful to those considering the
 technology for Superfund cleanups and represents a

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critical  step   in  the   development   and
commercialization of the treatment technology.

Overview of Stabilization/Solidification
Stabilization and  solidification are  treatment
processes designed to accomplish one or more of the
following:

  • Improve  the  handling  and  physical
     characteristics of the waste.
  • Decrease the surface area of the waste mass.
  • Limit the solubility of hazardous constituents.

  • Detoxify contained contaminants.

Stabilization is a  beneficial action  that occurs
through limiting the solubility or mobility of the
contaminants irrespective of a change  in physical
characteristics. Solidification implies that a benefit
is obtained through the production of a solidified
block, which has high structural integrity.

Stabilization processes are grouped into categories
according to  the  types of additives and processes
used. These categories are:  (1) cement, (2) lime plus
poz/.olan (fly ash, kiln dust, hydrated  silicic  acid,
etc.),  (3) thermoplastic (asphalt, bitumen,
polyethylene,  etc.),  (4) thermosetting organic
polymers (ureas, phenolics, epoxides, etc.),  (5)
vitrification, and (6)  miscellaneous  others. The
existing processes, although assumed to be chemical
in  nature, involve  little chemical alteration. The
waste particles may merely be microencapsulated,
which is particularly  true for organic contaminants
[5]. In situ stabilization/solidification is one
variation on the above categories of treatment
processes.

The IWT process is a cementitious process that also
uses proprietary additives and other pozzolans.
 Portland cement reaction products are a  fused
 mixture, in somewhat variable proportions of
 calcium, silicon, aluminum, and iron  oxides,  the
 main constituents  of which are usually hydrated
 calcium alumino-silicates and calcium silicates. This
 type of process is usually most applicable to treating
 inorganic wastes, such as incinerator  wastes  and
 other sources of heavy metals. Usually the purpose of
 adding other pozzolans, such as fly ash, is to produce
 a stronger product. Organics (such as oil and grease)
 in the soil may interfere with the cement bonding
 reactions by coating the soil particles. At  soil
 contents above 10  wt% interferences from organics-
 may occur.

 One possible approach that could reduce the mobility
 of organic contaminants in cemetitious systems is to
 use  an additive that interacts with the cement
matrix, while at the same time adsorbing the organic
material. Clay minerals offer one such possibility
and have been used for many years by the nuclear
industry [6]. Of particular interest is the use of clays,
reacted  with alkylammonium cations (quaternary
ammonium salts), to enhance clay-organic waste
interaction. Although the actual composition of the
IWT additive is proprietary information, it appears
that its  technology is similar to the approach using
organophilic clays. In addition to the chemical
bonding, IWT also claims that some of their additives
break  down the  contaminant to  harmless
compounds.

Stabilization/Solidification Technologies
and Superfund Response Actions
Section  121 (Cleanup Standards) of the  Superfund
Amendments and Reauthorization Act  (SARA) of
1986 requires that  remedies both be protective of
human  health and  the environment, and be  cost-
effective. SARA states  a strong preference for
remedies that are highly reliable and provide  long-
term protection. The statute also states a preference
for remedial actions that employ treatment that
permanently and significantly reduces the volume,
toxicity,  or mobility  of  hazardous waste.
Stabilization/solidification is one of the treatment
technologies with the potential to meet the cleanup
standards.

Stabilization/solidification has been  selected at
numerous Comprehensive Environmental Response,
Compensation and  Liability Act (CERCLA) sites to
reduce waste toxicity or mobility.  (The SITE
program demonstration of the IWT and Geo-Con
technologies was conducted at a closed electrical
service shop  in Hialeah, Fla.,  which  was not a
CERCLA site.)  A  comprehensive list of sites for
which stabilization/solidification has been chosen is
beyond the scope of this document. However, this
section discusses some of the general trends in the
 use of these technologies for CERCLA actions, gives
 some examples of site  remediations involving
 stabilization/solidification and  discusses the
 potentially applicable or  relevant and appropriate
 requirements  (ARARs)   for  the  use   of
 stabilization/solidification at CERCLA sites.

 Use of Stabilization/Solidification

 Both immediate removal activities and remedial
 actions under the CERCLA program have used or
 will use  some type of stabilization/solidification.
 Between fiscal years (FY) 85 and 88, at least nine
 removal actions involved  stabilization/solidification,
 usually using lime or  kiln  dust to  treat waste
 sludges.  As of the end of FY88,  stabiliza-
 tion/solidification had been selected as a cleanup
 remedy  in  38  Records  of Decision  (RODs) for

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 National Priorities List (NPL)  sites. Eighteen of
 these RODs were signed in FY88.

 Of the  CERCLA sites  for  which stabiliza-
 tion/solidification has been selected or  used,  the
 method has typically been applied to wastes (usually
 sludge, sediment, and surrounding soil) that  are
 acidic or contain heavy metals.  For instance,
 stabilization/solidification was selected to treat soil
 and sediments contaminated with metals at the
 following NPL sites: Sapp Battery in Florida,
 Marathon Battery in  New York, and Independent
 Nail in South. Carolina. As the  use of incineration
 increases, stabilization/solidification may be selected
 to treat residual  ash, if the ash requires further
 treatment to reduce the mobility of metals prior to
 redisposal  onsite.  This  application  of
 stabilization/solidification was chosen for the Geiger
 (C&M  Oil)  site, South Carolina. Stabilization has
 also been selected to treat soil contaminated with
 radioactive waste at  the Denver Radium site in
 Colorado.

 In addition, stabilization/solidification has  been
 selected  to treat wastes  containing  organic
 compounds. In an  application similar to Hialeah, in
 1986, stabilization/solidification was selected in the
 ROD for the Pepper Steel and Alloys, Inc. site in
 Florida for treatment of soil contaminated  with
 PCBs and heavy metals.  The cleanup occurred in
 1988, when the soil was excavated, separated  from
 debris, and mixed with Portland cement before being
 returned "to  the excavated area of the site. Like the
 Hialeah site, the site is sandy and overlies a shallow
 aquifer (4 to 5 ft below land surface). Other sites
 where stabilization/solidification was selected to
 treat organics include: York Oil  in  New  York, to
 treat soil  and sediment contaminated with metals,
 petroleum hydrocarbons and low concentration of
 other organics,  including PCBs; Fields Brook in
 Ohio, to treat sediments containing metals and
 organics, including PCBs; Liquid Disposal Landfill
 in Michigan, to treat soil and waste containing heavy
 metals  and organics,  including PCBs; Industrial
 Waste  Control  in Arkansas and  Bailey Waste
 Disposal in Texas,  to treat soil containing organics;
 and Chemical  Control  in New Jersey to treat soil
 containing heavy metals and organics.

 To date, no CERCLA cleanup has selected the in situ
 application method offered by IWT and Geo-Con and
 tested in this SITE demonstration. In most of the
 examples listed above, the application method for the
 stabilization/ solidification reagents  was  not
 specified in the ROD and was to be addressed in the
design phase of the remedial action.  The two  most
frequent  types of stabilization/solidification
treatment  are  bulk mixing in a pit and excavation
and treatment in a  tank. However,  in  situ
  stabilization/solidification was specified in the ROD
  for the Chemical Control site because of the small
  size of the site and other engineering difficulties.

  Role of Stabilization/Solidification in the Future

  Currently, many stabilization/solidification vendors
  use additives (such as dispersants and organophilic
  proprietary compounds) in conjunction with setting
  agents to improve the ability to bind organics  to the
  solid product. Because of the availability of these
  new mixtures,  stabilization/solidification  may be
  considered  more  frequently  to  treat soil
  contaminated with organic compounds, alone or
  together with metals. In addition to the IWT and
  Geo-Con  technologies,  the SITE  program is
  evaluating stabilization/solidification methods
  offered by five other vendors.  These additional
  demonstrations all involve  soil  and  sludge
 containing organic  compounds  as primary
 contaminants, such a-s solvents, PCBs, petroleum
 hydrocarbons, and coal tars. The demonstration of
 the IWT and Geo-Con technologies is the only SITE
 project    to    date    involving    in    situ
 stabilization/solidification.

 Evaluation of the effectiveness of available
 stabilization/solidification processes for a specific
 site and waste requires bench-scale testing, in which
 small samples of the waste and reagents are mixed
 and allowed to cure. The treated samples are then
 subjected to physical and chemical tests  such as
 those described  in Section 3  of this report.  Bench-
 scale tests can also assess the potential for emissions
 of volatile  compounds during the mixing process,
 which often involves the release of heat  during
 reactions between the waste  and the additives.
 Bench-scale testing of stabilization/solidification is
 currently being  implemented during the feasibility
 study and design phases at many CERCLA sites. It
 should be noted  that the tests available to evaluate
 this technology do not directly measure its long-term
 effectiveness.

 Regulatory Considerations

 CERCLA Section 121(d) requires onsite Superfund
 remedial actions to comply with federal, and more
 stringent state environmental requirements that are
 determined to be ARARs. The current NCP requires
 onsite removal  actions to comply with federal
ARARs  to the extent practicable. Two sets of federal
regulations that are potential ARARs  for in  situ
stabilization/solidification of PCB  waste are the
 Land Disposal  Restrictions (LDRs) under the
Resource Conservation and Recovery Act (RCRA)
and the PCB waste disposal regulations under the
Toxic Substances  Control  Act  (TSCA).  The
regulatory requirements are discussed in more detail
in Section  3 of this report. Regardless of  which

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regulations are ARARs, all Superfund cleanups must
be protective of human health and the environment.

Stabilization/solidification is not now considered a
best available demonstrated technology (BOAT) for a
RCRA hazardous waste that  contains organic
contaminants and is subject to the LDRs. OSWER
Directive 9347.1-02 (Apr. 17,  1989) states that for
the LDRs to be applicable, the  CERCLA response
action must constitute  placement of a restricted
RCRA hazardous waste. Placement does not occur if
wastes are moved within a unit  or are left in place.
Therefore, in situ  treatment, such  as for  the
stabilization/solidification process using IWT  and
Geo-Con technologies, does not  involve placement,
and the LDRs are not applicable.
Key Contacts
For more information on the demonstration of the
IWT/Geo-Con technology, please contact:

1.    EPA Project Manager, concerning the SITE
     demonstration and the Hialeah, Fla. site

        Ms. Mary K. Stinson
        Risk Reduction Engineering Laboratory
        GSA Raritan Depot - Bldg. 10
        Edison, NJ 08837
        (201) 321-6683

2.    International Waste Technologies  concerning
     the process.

        Mr. Jeffrey Newton
         150 N. Main St.
         Suite 910
        Wichita, KS 67202
         (316) 269-2660

3.   Geo-Con, Inc. concerning the deep-soil-mixing
     equipment.

         Mr. Brian Jasperse
         P.O. Box 17380
         Pittsburgh, PA 15235
         (412) 856-7700

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                                            Section 3
                            Technology Applications Analysis
 Introduction
 This section of the report addresses the applicability
 of the IWT in situ stabilization/solidification
 technology using the Geo-Con/DSM equipment to
 remediate various feedstocks based on the results of
 the SITE demonstration and other IWT and Geo-Con
 data. Since the results of the demonstration provide
 the most extensive database available, conclusions
 on the  effectiveness  of  the  process  and  its
 applicability to other potential cleanups  will be
 strongly influenced by those results. These are
 presented in detail in the  Technology Evaluation
 Report. Additional information on the IWT and Geo-
 Con technologies -- including a process description,
 vendor claims,  a summary of the demonstration
 results, and summaries of outside sources of data -
 are provided in Appendices A-D.

 To evaluate the combined technologies of IWT and
 Geo-Con, the following technical criteria were used:

   • Ability of the IWT additive to immobilize PCBs
     and other contaminants.

   • Durability of the solidified, treated soil mass ~
     which is indicated by results obtained  from
     many of the physical property tests.

   • Ability of the Geo-Con DSM equipment to blend
     a cementitious additive with contaminated soil.

 Following are the overall conclusions being drawn on
 the IWT and Geo-Con technologies. The Technology
 Evaluation subsection discusses the available  data
 from the demonstration and IWT  studies.  It also
 provides more detailed conclusions and discussion of
 applicability of the  IWT  and Geo-Con in  situ
 stabilization/solidification process. This is followed
 by subsections covering federal regulations, waste
 characteristics and performance of the technology,
 materials handling, personnel issues and procedures
 for evaluating stabilization/solidification.

 Conclusions
The conclusions stated for this  in situ stabiliza-
tion/solidification technology are drawn primarily
from the demonstration, but were also supplemented
by information  provided  by IWT  and LE on
laboratory studies. The conclusions are:

  •  PCBs do appear to be immobilized by  the
     process, based upon TCLP leach test and
     physical test results. However, for most of the
     tests,  PCB  concentrations in the soil were
     relatively low (<500 mg/kg), and the leachate
     concentration levels were low and very close to
     the  analytical detection  limits. Thus,
     confirmation of this conclusion is  not possible.
     In addition, the data that IWT  provided were
     for posttreatment soil  leachates only and a
     determination of immobilization is not possible.

  •  From laboratory studies  provided by IWT (both
     leach tests and more sophisticated tests to prove
    chemical bonding) immobilization of volatile
    and semivolatile organics appears possible, but
    since  pretreatment  leach tests were not
    performed, confirmation is not possible. The
    demonstration did not provide  sufficient data
    points to allow any conclusions to be drawn.
    (IWT  claims that  their  additive  was not
    designed for VOCs.) However, IWT claims the
    HWT-20 additive contain organophilic clays,
    and the literature [6] indicates that bonding of
    organics to some treated clays does occur, thus
    immobilization appears possible.

  • Immobilization of heavy metals is probable.
    However, insufficient data are  available from
    IWT  or the demonstration  to  provide
    confirmation. Cement-based  systems are
    usually effective on heavy metals, and the
    reported treated soil  leachates for  the  IWT
    technology are low - in most cases less than 100
    ug/L.

  •  IWT's  primary study efforts are to develop
    additives  that chemically  bond  to the
    contaminants, and most of its  test work is
    related to confirming  this.  However, the
    demonstration was not designed to prove this,
    thus no conclusions related to chemical bonding
    are offered.

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  • Physical properties of treated soil samples - in
    each case for samples of very  low organics
    content  (<1.6 wt%)  —  were  generally
    satisfactory,  except for  the  freeze/thaw
    weathering tests, which were performed only
    during the demonstration. The UCS values
    were high (300-500 psi),  the permeabilities
    were satisfactory (10-6 to 10-7 Cm/s), and the
    volume increase, due to the addition of HWT-20
    additive, was  low - about 8.5%  during the
    demonstration. The microstructural analyses
    showed a dense, homogeneous and low-porosity
    structure, which with the other results obtained
    (if the freeze/thaw difficulty can be corrected by
    IWT as they claim) indicates that the solidified
    mass has the potential for long-term durability.
    These physical results, where comparisons can
    be made, are approximately equivalent to test
    results where cement was substituted for HWT-
    20 during the demonstration.

  • The Geo-Con/DSM equipment appears to work
    well and to provide intimate mixing of additive
    and soil. Geo-Con  and  various Japanese
    vendors  have used in  situ  injection  to
    consolidate soils, construct slurry cut-off walls,
    etc. in all types of soils, thus, the equipment has
    a proven capability of use in a wide variety of
    soils and applications.

Applications  of  this  in  situ  process for
immobilization of PCBs, heavy metals and volatile
and semivolatile organics at low organics content in
the soil seems possible especially  for the heavy
metals. Even for high-organic-content wastes - up to
25 wt% ~ immobilization may be possible.  However,
physical properties of treated soil in cement-based
systems start to deteriorate at about 10 wt% organics
in the untreated soil.  Therefore, since only very
limited bench-scale studies have been performed and
there is no field work at the higher organic levels, it
is recommended that treatability studies (for both
chemical and physical characteristics) be performed
on each waste, whether low  or high in organic
content

As for the use of the Geo-Con DSM  equipment, few
limitations appear to exist. The DSM equipment, and
similar units in Japan, can operate in most soils and
in most climates, to a depth of more  than 100 ft.
However, some limitations may exist:

   « A volume increase is expected which may cause
     difficulties in restricted areas where land
     contours would be seriously altered. Also,  for
     high-organic-content wastes, where the IWT
     additive rate would be increased, the larger
     volume increase would be of even more concern.
  • Soil debris, such as large rocks and buried
    drums, would probably have to be excavated
    before auger injection. Special  injection
    equipment should be used for deeper obstacles.

  • Very low ambient temperatures (below  10°F)
    may cause freezing of the feed slurry before
    injection.

Evaluation  of Performance
The criteria defined in the SITE  Program
Demonstration Plan [7] to evaluate the IWT and
Geo-Con  in  situ stabilization/solidification
technology are:

  • Immobilization of PCBs as determined from
     leaching and permeability tests.

  • Long-term durability of  the solidified soil, as
     determined from various physical tests such as
     UCS, weathering (wet/dry and freeze/thaw),
     and microstructural analyses (microscopy  and
     X-ray diffraction).

  • Reliability  and versatility of  the mechanical
     equipment.

The above criteria are a direct approach to  the
evaluation of the effectiveness of the technology
before and after treatment.  A separate research
project to support the IWT  findings of chemical
bonding between additive and contaminant  was
outside the scope and intent of the commercial scale
SITE demonstration. The reaction  mechanisms do
help to explain the direct results obtained and  also
provides insight for extending the  results to other
applications.  A separate research  program  would
have  complemented the demonstration.  The
following discussions, using the available IWT and
Geo-Con  information, will provide more detailed
conclusions on the process, particularly as related to
the various physical and chemical  properties of the
treated soil.

 Chemical Test Results

The chemical analyses of soil and leachates, provide
 information  in evaluating the immobilization of the
 various contaminants. Leaching tests indicate the
 chemical stability of the solidified mass [8], its
 tendency to leach by water, and the mobility of
 contaminants contained in the solidified waste when
 they are in contact  with aqueous solutions. To
 properly evaluate immobilization, both pretreatment
 and posttreatment soil and  leachate analyses are
 required. The most extensive chemical analyses,
 measuring both  the waste  and  leachate
 compositions, before  and after treatment, were
                                                10

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performed as part of the SITE demonstration. Data
are also available from laboratory studies of IWT and
from the laboratory formulation studies by LE for
GE, using electric-service-shop soil. Most of this
work was related to PCBs, although some laboratory
studies were performed by IWT on metals, volatile
organics, and semi-volatile organics.  Since it is
important to know the quantity of the contaminants
in the  untreated and treated wastes  when
performing a leach test, the  most  complete
information is available from  the demonstration
where both analyses were performed. Some before
and  after  treatment leach  test  results were
performed by LE [1].

During the  demonstration,  the  IWT  in situ
stabilization/solidification process appeared to
immobilize the PCBs, which are  relatively immobile
contaminants,  even   without  treatment.
Unfortunately, due  to the relatively low levels of
PCBs measured in the soil at the  Hialeah site
(maximum 950 mg/kg untreated and  170 mg/kg
treated) during the  test, which  produced leachates
close  to  their detection  limit (0.1 ug/L),  more
information  at higher PCB concentrations in the
wastes is required to confirm immobilization.

Law Environmental treated in the laboratory soil
samples containing 83, 1,130, and 5,628 mg/kg PCBs
in the untreated soil, with varying amounts of HWT-
20 - from 0.05 to 0.25 Ib/lb dry soil (see Appendix D-
1). Four different leach tests were performed on both
the untreated  and treated soils  -- three versions of
the Extraction Procedure Toxicity (EP Tox), and the
Toxicity Characteristic Leaching Procedure (TCLP).
One EP Tox  test version  used  the standard
membrane filter;  prior experience has  shown that
PCBs  absorb onto the filter  and  provide low,
erroneous values. The other  two versions used a
glass fiber filter, one using site water and sulfurous
acid to reduce  the pH to 5.0, and the other using the
standard acetic-acid leach medium.

The results of these tests showed the following:

   •  For 'the  low-PCB-concentration  soils,
     untreated-soil leachate values, using only the
     standard EP Tox with a membrane filter, were
     below the detection limit (1.0 ug/L).

   •  For the medium-PCB concentration soils (1,130
     mg/kg), 58% to 94% concentration reductions
     (using the glass fiber filter) were seen, with the
     treated-soil leachate concentrations in the
     range 2.6 to 10.0 pg/L. These  values did not
     relate to the additive rates,  which were in a
     narrow range of 0.15 to 0.18 Ib/lb dry soil.

   •  For the high-PCB-concentration  soils (5,628
     mg/kg), 0% to 90% concentration reductions
     (using the glass fiber filter) were seen, with the
     treated-soil leachate concentrations  in  the
     range < 1 .to 98 ug/L. The treated soil leachate
     value of 98 ug/L was with an additive  rate of
     0.05 Ib/lb dry soil. At the higher additive rates
     of 0.15 and 0.25 Ib, the leachate values  ranged
     from <1 to 32 ug/L,. which is a concentration
     reduction of 51% to 90%.

  •  For the TCLP results, the treated-soil leachate
     values for  all five samples —  from low  to high
     soil-PCB  levels  —  were greater  than  the
     untreated-soil leachate values. LE had  no
     confirmed  explanation for this, and suggested
     that possibly the leaching fluid (Fluid #2 with a
     pH of 2.8) was the cause.  The TCLP was
     developed to overcome the shortcomings of EP
     Tox for the leaching of organics, and therefore,
     it  would  be  expected to  provide  more
     satisfactory results. Nevertheless, based on
     available  leach test results, the studies
     performed by LE for  GE using HWT-20  did not
     show immobilization of PCBs.

For each  of the three EP  Tox tests, LE found a
relationship between the  PCB  concentration in the
leachate and the ratio of HWT-20 additive to water.
It found the curve  went  though a minimum at an
additive-to-water ratio of 1.0-1.5. This result was
likened to the optimum moisture content for cement,
which might tend to confirm the validity of the EP
Tox results versus the TCLP values.

In a second group of samples, LE mixed HWT-20 as a
slurry  with the soil, instead of mixing it dry. The
additive was mixed in concentrations of 0.12 to 0.20
Ib/lb dry soil. Untreated soil concentrations of PCBs
were in the range of 893-3,944 mg/kg. Treated soil
leachates (using EP Tox with glass fiber filter)
ranged from 2.4-4.5 ug/L.  One untreated soil  sample
with a PCB concentration of 5,719 mg/kg had a
leachate concentration of 11.0 ug/L. A table of results
is included in Appendix D.

If the TCLP results are discarded, the EP Tox results
from the LE work show  immobilization of PCBs.
However, based on the LE report, there is not a valid
reason to eliminate the TCLP results. Thus, the LE
work is inconclusive on  the ability of HWT-20 to
immobilize PCBs. See  Appendix D-l  for more
detailed information.

IWT performed some laboratory experiments before
the demonstration. One was at very  high  PCB
concentrations  in a soil  like at Hialeah —  28,800
mg/kg — the other at a moderate value — 290 mg/kg —
the same order of magnitude as some untreated soils
in the  demonstration. After treatment for the high
concentration soil - 0.20 Ib HWT-20/lb  dry soil -
only 10 wt% PCB could be extracted by methylene
                                                11

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chloride solvent. In addition, IWT reported a TCLP
leachate value of 12.5 mg/L, and very high levels of
chlorinated benzenes  in the  soil,  which  they
attributed to the decomposition of PCBs. In the other
test, the additive rate was 0.15 Ib and only two-thirds
of the PCBs could be extracted by a solvent.  Also,
volatile organics measured in the untreated soil were
not  detected  in the treated soil. Thus,  it was
concluded by IWT  that HWT-20 was bonded to the
PCBs, which  seems a reasonable possibility.  It
should be noted that the only chlorinated benzene
(chlorobenzene) measured during the demonstration
existed in the same proportion to the other VOCs  in
both the untreated and treated soil,  so this IWT
observation was not confirmed.

During the demonstration, GE  collected and
analyzed samples from two locations in Sector B and
two  locations just south of Sector  B. The samples
outside the sector  (by 1 ft and 2 ft) showed no
consolidation,  indicating that the HWT-20 additive
did not spread beyond the test sector, and leach tests
were not performed. For the other two groups  of
samples, one was near Sample Location B-20  in an
area where column overlap (see Appendix A for more
information) was  poor and  the other was  near
Sample Location B-21. Samples were collected  at six
depths (maximum  17 ft)  at  each  location. These
treated soil samples were analyzed for PCBs. TCLP
leach tests were performed approximately 3 weeks
after the soil samples were collected, thus allowing a
3-week curing period. The results are shown in Table
1, with a summary of the data sheets  from the
laboratory report provided in Appendix D-3.

 Table 1. Posttreatment Soil and Leachate Analyses of
        Samples Collected by GE
   Location              PCBs in soil,  PCBs in TCLP
     near       Depth, ft      mg/kg     leachate,
B-21
B-21
B-21
B-21
B-21
B-21
B-20
B-20
B-20
B-20
B-20
B-20
3.0 - 3.6
5.0 - 5.75
7.0 - 7.8
9.5-11.0
12.5 - 14.0
15.5 - 17.0
1.5 - 3.0
3.0 - 4.5
6.0 -. 7.4
7.4 - 9.0
10.5 - 12.0
13.5 - 15.0
34.9
182.0
206.0
166.0
32.9
13.7
22.8
47.7
72.7
57.4
2.0
1.0
1.20
<0.10
0.22
0.12
<0.10
0.11
<0.10
<0.10
<0.10
<0.10
<0.10
<0.10
In the area where treated soil columns overlapped
poorly, the PCB concentration in the soil ranged
from 1.0 to 72.7 mg/kg, with the maximum value at a
depth of 6.0-7.5 ft. All corresponding leachate results
were below the detection limit of 0.1 ug/L. For the
samples near Location B-21, where the overlap was
satisfactory, the PCBs in the soil ranged from 13.7 to
206 mg/kg, with the maximum value at a depth of
7.0-7.8 ft. In this area, the PCB concentrations in the
TCLP were above the detection limit at 4 of the 6
depths. The maximum TCLP leachate-concentratiori
was 1.2 ug/L at a depth where the soil concentration
was about 35 mg/kg PCBs. The next highest leachate
value was 0.22 ug/L, which occurred for soil  at the
highest concentration value. At the second-highest
soil  value  of 182  mg/kg PCBs, the  leachate
concentration was below  the detection limit.  These
results showed that the more properly treated soil,
although higher in  PCB concentrations, showed
detectable quantities of PCB in the TCLP extracts,
while for the area of poor overlap, all leachates had
PCB concentrations below detection limits. The data
are similar to the  demonstration values and,
although very low, do not clarify whether the IWT
process immobilized PCBs.

Prior to the demonstration,  EPA performed tests on
samples previously prepared by LE as a preliminary
evaluation of the technology. The 3 samples  tested
had PCB concentrations ranging from 4,100 to 5,700
mg/kg. They were prepared from a batch of untreated
soil with a PCB concentration  reported  by  LE  as
5,628 mg/kg. This  indicated  that the HWT-20
neither degraded or bonded to the PCBs. The 3 TCLP
leachates each  had PCB  concentrations below the
detection limit of 1.0 ug/L, which would support the
possibility of PCB immobilization.

Thus, using all available sources,  it appears that
some data show immobilization of PCBs, while other
data are inconclusive. Therefore, although it appears
that  the IWT additives may immobilize PCBs, the
results are not conclusive.

Additional information is provided by IWT  on
various laboratory studies it has performed,  which
were presented in informal papers it has distributed.
A copy of the most recent one was provided for the
Vendor Claims section, Appendix B. Other papers
are summarized as Appendices D-4 and D-5. The
results presented provide various TCLP leachate
results, after treatment only, for volatile organics,
semi-volatile organics and heavy metals. In addition,
tests using  hexane and  methylene  chloride
extractions were performed, to show that bonding of
the contaminants to  the  additive occurred.  If the
organic contaminants are chemically bonded  to the
additive,  the ability  to extract them, even with  an
efficient solvent, is reduced. It would then follow that
these organics may be immobilized.

Many examples are cited by IWT on its  ability to
immobilize volatile  and semivolatile organics.  In
most cases, wastes containing up to 10,000 mg/kg of
                                                12

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 an individual organic were reduced to less than 2
 mg/L, with many values below detection limits.
 However, the detection limits are not defined, and
 corresponding values for  untreated waste leachates
 do not exist. If the detection limits were tens or
 hundreds of parts per billion, then immobilization
 may have occurred. In one example, where the waste
 contained 26,500 mg/kg xylenes, the leachate value
 was 4,605 mg/L, which is very high. After adjusting
 the additive formulation, the value was reduced to 48
 mg/L, which is still large  and may not differ
 significantly from a TCLP leachate  value for
 untreated waste.  Thus, the ability of the  IWT
 additive to immobilize VOCs or semivolatiles cannot
 be clearly determined from the limited  leach test
 data available.

 Leachate values for metals were below 1.0 mg/L in
 almost all cases reported, with most of them below
 0.1 mg/L, which  may meet  existing regulatory
 standards for land disposal restrictions and delisting.
 However, in all tests, the concentration in the wastes
 was tens or hundreds of parts per million, which is
 not large. Since TCLP leachate values for untreated
 soils were not provided,  except during  the
 demonstration immobilization of the metals cannot
 be determined from the available  data. However,
 most cement-based additives can immobilize heavy
 metals, so it is reasonable  to believe  the  IWT
 additives also have the capability.

 Chemical Bonding Tests-
 Currently the most extensive studies by IWT, which
 were outside the  scope of  the demonstration,
 [9,10,11] are the tests to prove that its additive bonds
 to, or  destroys, the organic contaminants (see
 Appendix D-6). If bonding occurs, even if the forces of
 attraction are weak, the mobility of the contaminant
 is reduced and the  physical integrity of the treated
 waste may become less important, since bonding, as
 well as encapsulation, will  prevent contaminant
 mobility.  If this research is successful, the  IWT
 technology might  meet  many  of  the current or
potential regulations for both organics and  metals
 (where reductions in the contaminant concentration
 in the wastes are measured). Various tests have been
 used in attempts to prove this claim, such as direct
extraction with an  organic  solvent,  Fourier
transform infrared (FTIR), and differential scanning
calorimetry (DSC).  These tests,  and the protocol to
evaluate the process try to show  bonding in the
following manner:

Solvent Extraction—
 During sample preparation for analyses of VOCs and
semi-volatiles, the organics are extracted from the
waste by hexane and the quantity is measured by gas
chromatography/mass spectrometry (GC/MS). If
bonding occurs, the solvent may not extract all of the
contaminant and it will appear to have a reduced
 concentration level. If hexane does not extract the
 toxin, water in most cases will not either. The tests
 reported by IWT have shown reduced concentration
 levels of contaminants after treatment with HWT
 additives.

 FTIR—Shifts  in infrared vibrational frequencies  of
 organic bonds occurred after treatment, showing a
 change in bond length between atoms. This indicates
 that weak bonding has occurred. Even weak bonding
 of this  type  should reduce the mobility of the
 contaminants.

 DSC—This procedure measures the changes in
 temperature  and  energies required to release the
 contaminants from the soil matrix before and after
 treatment. If for example, the heat of vaporization
 increases, compared to the pure compound not in the
 solid matrix, as shown for the IWT additive [10], this
 indicates a bond may exist, restraining the release.
 IWT also claims that there is a breakdown in the
 organic molecules to smaller molecules, and that the
 energy for release of the organics  increases.
 However, elevated temperatures are required when
 performing a DSC analysis, and clays (which are
 aluminosilicates related  to zeolites,  a known
 catalytic group) are known to catalyze many organic
 reactions.  In proving  chemical bonding  or
 degradation,  the  key is  whether these  reactions
 occurred before  heating;  there is  no  evidence
 provided to this effect.

 Evidence from solvent extraction and FTIR studies
 suggests that  weak bonding probably occurs between
 many contaminants and the IWT additive. However,
 the basic IR spectra of the organics were observed in
 mixtures of HWT-20 and organics, with only modest
 frequency shifts. In addition, the extraction results of
 IWT showed  only partial recovery  of  unaltered
 organics. However, the demonstration results and
 LE tests showed no evidence of PCB or VOC
 degradation. Thus, it is likely that the various IWT
 additives can reduce the mobility of many organic
 contaminants.

 Physical Test Results

 The physical  tests - UCS, weathering (wet/dry and
 freeze/thaw), and permeability  --  provide
 information on the potential durability  of treated
 waste.  Permeability is also  a strong factor
 influencing  contaminant  mobility.  However,
 quantitative relations  between the  time the
 solidified mass can maintain  its integrity and the
 test results (including microstructural observations)
do not exist.

The most extensive physical testing on the  IWT
process  was  performed in  the SITE project and
reported in the Technology Evaluation Report [12].
This not only included the demonstration results, but
                                               13

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"screening test" results [13] on samples provided by
LE to obtain a preliminary evaluation  of the
technology.  The  only additional  information
provided by IWT are data obtained by  Law
Environmental for  GE  in 1986  on laboratory
prepared samples (using the same  electric-service-
shop soil) and from core samples taken from Sector B
shortly after the demonstration. Thus, all physical
test data are based on soil with a very low organic
content from one small plant location. As a result,
information on physical properties exists for only a
very narrow range of contaminated soils.

Unconfined Compressive Strength-
Unconfined compressive strength is a primary
indicator of durability of solidified  wastes. The
results of the samples  taken from  Sector B and C
show very satisfactory strengths for  the  solidified
material relative to EPA's guideline minimum of 50
psi [3] for stabilization/solidification  systems. The
results ranged from 75 to 579 psi in Sector B and 247
to 866 psi in Sector C. Results on laboratory prepared
samples by  LE, with additive concentrations
between 0.10 Ib HWT-20/lb dry soil and 0.25 Ib
HWT-20Ab dry soil, ranged from 198 to 2,127 psi (see
Appendix  D-2  for more  details). The  moisture
contents of the  laboratory-treated soil samples (2.8
wt%-13.6 wt%) were considerably lower than for the
average of the field samples (18 wt%). The higher
UCS values for the LE samples were at the higher
moisture levels. The data does not show a definitive
trend of UCS versus additive dosage rate at either
high or low moisture content. It is possible that the
samples with  very low  moisture content  were
incompletely hydrated, thus weakening the cement
matrix. Another potential factor affecting UCS (not
observed) is the degree of uniformity of the soil-
additive mixing. This would probably favor the
laboratory results, where the  mixing should be
better than that obtained in the field.

Three samples from a second batch of site soil, which
were prepared by  LE [14] using the additive in a
slurry form (compared to the earlier  formulations
using dry additive addition), were tested by EPA
during the Technology Screening Tests [13].  They
produced UCS values of 418-1,185 psi for treated-
soil moisture contents in the range of 8.6 wt%-16.1
wt%. Laboratory formulations  during the
demonstration by NUS Corp.,  the laboratory
analyses contractor, using site  soil — with Type 1
Portland cement substituted for HWT-20 at 15 wt%
and 20 wt% cement - produced equivalent results at
approximately the same moisture levels. Thus,  the
HWT-20 produces UCS values equivalent to  using
cement.

All these  UCS results for soil with a very low
organics content are quite satisfactory compared to
the EPA guideline minimum of 50 psi. Cement-based
waste treatment systems are typically in the range of
15-150 psi [4], although a comparison may not be fair
without knowing the weight of additives used or the
organics contents of the waste. High  UCS  values
imply the potential for  maintaining structural
integrity for many years. In conclusion, the  UCS
values are quite good and indicate a potential for
long-term structural integrity.

Permeability-
Permeability (also called hydraulic conductivity)
indicates the degree to which the material permits
the passage  of water, and is thus one measure of
potential for contaminants  to be released to the
environment. It would also be a factor in estimating
the potential for long-term durability of the treated
waste. Permeability depends on the  solidified
material's density, degree of saturation, and particle
size distribution, as well as pore size, void ratio,
interconnecting channels and the liquid  pressure.
Except for one value obtained by LE [13] and 3
values obtained during the EPA screening tests all
values available are from the demonstration. The
demonstration values averaged about  4xlO-7  cm/s,
while the screening tests averaged 2.7x10-8 cm/s, and
the one value in the LE laboratory tests was 7.6x10-8
cm/s. Thus, it appears that the field data are an  order
of magnitude higher than the laboratory data. All
the treated  values are very low compared to the
untreated soil values, which averaged about 3xlO-2
cm/s. As a point of reference, cement systems usually
can attain permeabilities of 10-5 to 10-6 Cm/s [15].
Therefore, it is concluded that the IWT process can
produce a solidified mass of low permeability, which
is marginally acceptable when compared to the EPA
criterion of  10'7 cm/s - the value targeted for soil
barrier liners for landfills used for hazardous waste
disposal. In  addition, this large decrease, compared
to the untreated soil, indicates that the groundwater
will flow around, not through, the treated block.
Thus, if only  one  large mass is produced, the
contaminants  will  remain isolated from the
groundwater as long as the durability of the
monolith is maintained.

Weathering-
Weathering effects  can  break down  the internal
structure of the solidified soil, producing potential
paths for  water flow, which would  increase
permeability and the potential for contaminant
leaching  and  weaken the solidified  mass.
' Weathering tests, which are more severe than field
conditions  in  terms of the rate and degree  of
temperature change, only provide an  indication of
the short-term (12 cycles) treated-soil integrity  in
the face of natural weathering stresses. The tests are
recommended as a means of comparing weathering
performance of different processes, but cannot be
                                                14

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used to predict the long-term durability of solidified
masses.

Twelve-cycle wet/dry and freeze/thaw tests were
performed during the demonstration for all treated
soil samples. The average of the cumulative relative
weight-losses between test specimen and control for
the 37 wet/dry tests  was approximately 0.1%, with
the absolute weight losses of the test specimens less
than 0.4%. For the 38 freeze/thaw tests, the average
cumulative relative weight loss was 6.3%, with the
absolute weight loss  of the control specimens
approximately 0.3, the same as for the wet/dry tests.

Freeze/thaw weathering tests, although  not of
concern at the Hialeah site, are of concern in more
northerly climates. The results are of concern
because of the recognized potential for frost damage
of concrete structures. The test uses a greater rate of
cooling than the maximum of about 5°F/h that is
expected in nature. In addition, the tests are carried
out on specimens that are nearly water saturated,
where the water can rapidly freeze and cause
fracturing of the solidified waste,  increasing the
permeability of the solidified mass.  Relatively dry
concrete  (such as  that used for above-grade
structures such as buildings) —  below 80% of
saturation level — is less likely to fracture than
saturated material.

Tests for UCS were performed on approximately one-
half of the test specimens and controls after the 12
weathering cycles. For all the controls and wet/dry
specimens, the UCS results were comparable to the
unweathered  values. However, for the freeze/thaw
test specimens, when the weight loss exceeded 3%,
UCS values deteriorated, approaching zero at about
10% weight  loss. Permeabilities  performed  on
wet/dry and freeze/thaw test specimens showed no
apparent  increases compared to  unweathered
specimens, although freeze/thaw samples  with high
weight losses — 10% and above — were not tested.

Therefore, it can be concluded that the IWT process
will maintain its integrity through wet/dry cycling.
However, freeze/thaw  cycling produces  severe
degradation of the solidified mass.  Without
formulation changes in the additive (which IWT
claims they can accomplish), severe problems might
be encountered with this process in cold climates. A
scheduled long-term monitoring program exists,
during which the treated soil will be sampled
annually. This will provide additional information
on durability of the solidified mass.  The first long-
term sampling occurred in April 1989.

Bulk Density-
Bulk densities were measured on all pretreatment
and posttreatment samples from the  demonstration.
Some other posttreatment values were provided by
GE (all on samples prepared by LE for GE) from the
first laboratory studies reported by LE, and from the
screening tests performed by the EPA.

For the demonstration,  the bulk density increase
with treatment was quite satisfactory. The average
density gain was 21%, changing from 1.55 g/mL (96.7
Ib/ft3) to 1.88 g/mL (117.3 Ib/ft3)  for a 32% increase
(HWT-20 plus water) in mass. The results of the 3
treated-soil samples  provided by GE and measured
by EPA during the screening tests were comparable
to the  samples from the field, and averaged  1.83
g/mL  (114.2 Ib/ft3). The  earlier laboratory
formulations — with additive dosage rates of 0.10 to
0.25 Ib HWT-20/lb soil - ranged from 1.48 mg/L (92.3
Ib/ft3)  to 1.86 g/mL (116.0  Ib/ft3). These latter
samples  had a moisture content ranging from 2.8
wt% to 13.6 wt%, with the lowest bulk-density values
at the highest moisture content. Both groups of test
specimens were lower in moisture content than the
posttreatment field samples.  For the samples
described above, untreated-soil bulk densities were
not performed. Therefore, it is concluded that a
significant bulk-density increase on soil treatment;
about 20% is likely at an additive  dosage of 0.17 Ib/lb
of dry  soil; and a small but significant volume
increase occurs.

Based on all the physical test results performed on
IWT treated-soil samples, it would be expected that a
potential for long-term integrity  of the treated soil
exists if the problem for freeze/thaw degradation is
overcome.

Microstructural Results

Optical microscopy, scanning electron microscopy,
and X-ray diffraction analyses were  performed on
untreated- and treated-soil samples during the SITE
demonstration. These methods are commonly used
techniques for understanding the mechanism of
structural degradation  of  soil,  cement,  and soil-
cement mixtures, both with and without the addition
of inorganic and organic compounds. Relatively few
studies exist  of the microstructure of complex
waste/soil mixtures  such as  those resulting from
stabilization/solidification  procedures. Thus,
interpretation of microstructural observations may
in some cases be  difficult.  However,  valid
information can be obtained on  the potential
durability of the solidified mass. These observations
complement the weathering test  results, which  are
short-term measures of solidified mass integrity, and
UCS test results, which are an indirect indication of
durability. The microstructural studies provide
information on the potentials for  structural changes
over  the long-term,  although  quantitative
predictions on durability are not possible.

The results show that the solidified material has a
potential for long-term durability. The  solidified
                                                15

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mass is dense, homogeneous and of low porosity.
Compositional variations in  the vertical and
horizontal direction, based on the consistency of the
mineral structure from sample to sample, were
absent. Thus, it appears that mixing by the Geo-Con
DSM equipment was satisfactory. It would seem that
the low porosity should reduce the susceptibility to
damage from wet/dry and particularly freeze/thaw
cycles, by reducing the quantity of water in the pores
of the solid (water in the pores would freeze and may
cause  fracture). However,  the  test specimen
degradation occurring in the freeze/thaw cycling
tests appears to conflict with the expected
performance of low porosity  solids  with high
strength.

Operations

For this SITE technology, IWT was the provider of
the chemical additive, and Geo-Con performed the
remedial operations. Geo-Con was responsible for the
slurry preparation, flow control of additive and
water, and soil injection and mixing. As indicated in
Appendix B on  Vendor Claims, Geo-Con has
substantial experience in shallow- and deep-soil-
mixing for contaminated  soils, lagoon closures and
structural reinforcement.

Equipment  operations during the demonstration
were satisfactory. Some minor operating problems,
readily fixable, were encountered, as described in the
Demonstration Report [12]. These minor difficulties
included: deviations in the location of the auger from
the designated point; a major water leak in the auger
drill head, which eliminated the supplemental water
for the last 21 soil columns; and inability to maintain
automatic feed control of the HWT-20 and water to
the auger.

Geo-Con has considerable experience in many types
of soil improvement operations.  They have
constructed  more than 400 slurry cut-off walls and
performed  work on soil  capping,  lagoon and
landfilling closures, soil and sludge stabilization and
foundation strengthening.   In addition, the
technology concept is used by others in the U.S. and
has been extensively used in Japan for about twenty
years.

Overall, the conclusion is that Geo-Con provides a
technology that has proven to be technically sound in
most types of soils and should be considered as a
valid option where in situ stabilization/solidification
or solidification technologies are  deemed desirable.

Summary of Performance

Stabilization/solidification  technologies generally
reduce contaminant mobility, particularly for toxic
metals, and increase volume.  These  techniques
nearly always leave some uncertainty about long-
term effectiveness, because laboratory tests can
neither fully duplicate field conditions over long
periods of time, nor establish what actually happens
to the contaminants during treatment [15,16]. This
is true for the IWT/Geo-Con in situ technology also.

It can be concluded that the overall physical
properties of low-concentration-organics soil treated
by the IWT in situ process are satisfactory. However,
some potential for durability difficulties under
freeze/thaw conditions exists. Although IWT claims
to be able to process wastes that are high in organics,
physical test data that might indicate the potential
for long-term durability do not exist. However, IWT
claims that chemical bonding is the key aspect of its
technology,  and  its  research  and additive
development is based on this approach; success in
this effort will reduce contaminant mobility even if
structural integrity of the solidified mass cannot be
maintained.

The only field experience of IWT is at the GE site in
Hialeah, Fla. For the SITE  demonstration,  the
ability of the HWT-20 additive to immobilize PCBs is
not conclusive. However, IWT's laboratory studies
indicate that PCBs probably can be immobilized.  For
the immobilization of volatile  and semi-volatile
organics and heavy metals, insufficient data exists
from the demonstration to draw any conclusions.
However, it is possible that the HWT additives
provided  by IWT are able to immobilize some
organics and metals, based on some IWT laboratory
results and the fact that some treated organophilic
clays [6] with similarities to the HWT family of
additives are known to bond to organics and metals.

The Geo-Con deep-soil-mixing equipment worked
well at  the  Hialeah site. Along with  their other
experience  in related work Geo-Con offers a
technology that should be considered as  a valid
option for in situ stabilization/  solidification
applications.


Environmental  Regulations  Pertinent to
In Situ Stabilization/Solidification
This section  discusses selected EPA guidance
concerning federal environmental regulations that
may   pertain   to   the   use   of  in  situ
stabilization/solidification of PCBs and hazardous
waste at CERCLA sites. Most of the discussion
pertains to any in situ  treatment technique. It is
beyond  the  scope  of this document to provide a
comprehensive description of all regulations that
may pertain to the  implementation of these
technologies. More information  on regulations
pertaining to CERCLA  actions is available in the
CERCLA Compliance with Other Laws Manual  [17]
and the series Superfund Land Disposal Restriction
(LDR) Guides [18-23]. Also, although the discussion
                                                16

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focuses on CERCLA activities, it should be helpful to
those contemplating the use of this technology for
other remedial activities, such as those under RCRA
corrective action or RCRA closure.
In Situ vs Staged Treatment

The term "in situ" is a Latin term meaning "in a
natural or original position." The term "in place" is
often used interchangeably with "in situ." In situ
treatment describes treatment of waste that has not
been excavated. In practice, treatment may not be
feasible or cost-effective unless the waste is first
excavated,  moved, or consolidated, prior  to
redeposition in a  location specifically designed for
treatment. Although technically this "staged" treat-
ment is not treatment in place, the same techniques
could  be used,  such as  the application  of
stabilization/solidification agents using an auger.

Staged  treatment may trigger  regulatory
requirements  additional  to those that apply to
treatment of waste that has not been excavated. For
this reason, the discussion that follows distinguishes
between in situ treatment and staged treatment. For
the purpose of this discussion, in situ treatment
refers  only to the treatment of waste in place,
without prior excavation. Staged treatment is the
application of in situ techniques to  waste that first
has been excavated.
The Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA)

The Comprehensive Environmental  Response,
Compensation, and Liability Act (CERCLA) of 1980,
as amended by the  Superfund Amendments and
Reauthorization Act (SARA) of 1986 provides for
federal authority to respond to releases of hazardous
substances  to  air,  water,  and land.  CERCLA
authorized EPA to revise the National Oil and
Hazardous Substances Pollution Contingency Plan
(NCP)" to include responses to hazardous substance
releases. The NCP defines methods and criteria for
determining the appropriate  extent of removal,
remedial, and other measures. The latest revisions to
the NCP, which reflect SARA, will be promulgated
in early 1990. Specific techniques mentioned in the
NCP for remedial action at hazardous waste sites
include  solidification technology for  handling
contaminated soil, sediment, and waste.

Section  121  (Cleanup Standards) of SARA requires
that remedies be protective of human health and the
environment and be cost-effective.  SARA states  a
preference for remedies  that are highly reliable;
provide  long-term protection; and employ treatment
that permanently and significantly reduces  the
volume, toxicity, or mobility of hazardous waste.
Lastly, section 121 requires compliance with Federal
and State applicable and relevant and appropriate
requirements (ARARs), and provides six conditions
under  which the ARARs  may  be waived.  The
proposed NCP defines applicable requirements as
those  standards, requirements,  criteria, or
limitations promulgated under Federal or State law
for which the jurisdictional prerequisites fully
address the circumstances at the site or the proposed
remedial activity.  Relevant and  appropriate
requirements are those that, while not "applicable,"
address problems or situations sufficiently similar to
those encountered at the CERCLA site that their use
is well-suited to the site.

The discussion that follows first reviews regulatory
requirements that may be applicable or relevant and
appropriate  to in situ or staged stabilization/
solidification at a CERCLA site.  The guidance on
how to determine whether such requirements are
ARARs follows the  discussion of each  set  of
regulatory requirements.

Resource Conservation and Recovery Act
(RCRA), as Amended by the Hazardous and Solid
Waste  Amendments (HSWA) of 1984

Some of the regulations promulgated under RCRA
have potential  application to  in situ and  staged
stabilization/solidification at CERCLA sites. RCRA
regulations define hazardous wastes,  and regulate
their transport, treatment, storage, and  disposal.
Examples of RCRA requirements  that may be
ARARs for CERCLA activities include  regulations
for treatment in a tank, performance of incinerators,
closure of landfills and surface impoundments, and
treatment standards for land disposal (the LDRs).

Definition of Treatment-
Under RCRA section 260.10 treatment is  defined as:

      ...any method, technique, or process, including
      neutralization, designed to change the
      physical, chemical, or laiological character or
      composition of any hazardous waste so as to
      neutralize such  waste, or so as  to recover
      energy or material resources from the waste,
      or so as to render such waste non-hazardous,
      or less hazardous; safer to transport, store, or
      dispose of; or amenable for recovery, amenable
      for storage, or reduced in volume.

Therefore, stabilization/solidification  of hazardous
waste is considered treatment under RCRA because
it  changes the  chemical  and/or  physical
characteristics of the  waste in order to render it
nonhazardous or less hazardous, or easier to manage.

The requirements for treatment of hazardous waste
fall into two general categories: treatment in a unit
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or  treatment prior to land disposal.  Most
requirements for treatment in a unit are unit-
specillc design and operating standards. Treatment
is regulated in the following RCRA-defined  units:
tanks, surface impoundments, waste piles, landfills,
land treatment units, incinerators, and thermal
treatment units. In addition to design and operating
standards, requirements for incinerators include a
performance standard of 99.99 percent destruction
and removal efficiency (DRE) (99.9999 percent ORE
for dioxins), in the stack gas emissions.

The requirements for treatment  prior to  land
disposal, or the land disposal restrictions, are
concentrations of a contaminant in the  waste or
waste leachate that must be achieved in order to land
dispose the waste. The LDRs are discussed in more
detail in a later section.

RCRA and In Situ Treatment-
If in situ treatment is used to treat hazardous waste
in a RCRA-regulated  unit (for instance, a surface
impoundment), unit-specific standards would be
pertinent. However, in many cases in situ treatment
will be used as part of a RCRA Corrective Action or
CERCLA cleanup to treat wastes that have breached
any unit boundaries that may have existed, and unit-
specific standards would not apply.

In these cases, because wastes treated in situ are
likely to remain in place over the long term, in situ
treatment is  usually governed by site-specific
cleanup standards, which are often risk based.
Cleanup  standards for  in  situ  stabiliza-
tion/solidification may take the form of permissible
levels of certain  hazardous constituents in the
leachate generated from a standard test, such  as the
TCLP or EP Toxicity tests. Cleanup standards may
also be expressed as concentrations of hazardous
constituents in the treated waste, rather than  in the
leachate. Because most  stabilization/solidification
agents do not destroy contaminants, but rather make
them less available to the environment, this
technology may have  difficulty meeting a cleanup
goal based on an analysis of total waste composition.

If soil and debris are being treated, and the LDRs are
applicable, guidance  for alternative  treatability
variance  levels and technologies may apply.
Immobilization  is  specified  for  inorganic
contaminants, and standards are expressed as
ranges of percent reductions in TCLP  leachate
values. The ranges vary, but all fall between 90 and
99.9 percent.  Specific variance levels for soil  and
debris are given in OSWER Directive 9347.3-06FS
[23].

Since hazardous waste treated in situ will be  left in
place, provisions regulating closure and post-closure
of disposal facilities for hazardous waste may  apply.
Disposal or landfill closure  requires capping and
post-closure care,  including  groundwater
monitoring, for at least 30 years. "Clean" closure of a
RCRA unit requires removal and decontamination
that would allow the site to remain without care or
supervision after closure. Hybrid closure combines
elements of landfill closure and clean closure. At this
time, draft guidance defining performance standards
for clean closure are health-based standards for
constituent concentrations determined  by total
waste analysis, not leachate concentrations.

It is important to note that many in situ treatment
methods include  treatment steps aboveground, such
as treatment of volatile organic  contaminants
removed  from the ground via in situ  vacuum
extraction. Above-ground treatment steps would be
regulated by unit-specific standards.

RCRA and Staged Treatment-
If in situ  treatment techniques are used  to treat
waste that has been excavated and  staged, RCRA
requirements, in addition to  those described above,
may apply. The potential  requirements would
pertain to storing and redisposing of the waste, and
include land disposal restrictions and standards for
construction  and managing land disposal units.
Under certain conditions, however, such standards
would not apply during a CERCLA cleanup or RCRA
corrective  action.  Applicability  of RCRA
requirements to CERCLA activities is discussed in a
later section.

Land Disposal Restrictions-
The RCRA land disposal restrictions (LDRs) are
potential ARARs at many CERCLA sites. The RCRA
LDRs prohibit, with certain exceptions, the land dis-
posal of hazardous wastes, unless the wastes are first
treated to standards established by EPA in RCRA
section 3004(d). EPA has promulgated regulations
for compliance with the  LDRs in 40  CFR Part 268.
These regulations specify the treatment standards to
which wastes that are subject to the restrictions
("restricted waste") must be treated before  being
land disposed. The standards are based on what can
be achieved using best demonstrated available
technology (BOAT). BOAT standards are typically
expressed as  concentrations  of waste constituents
that may remain after the waste has been treated,
but in some cases are expressed as a  specific
technology.

If the  LDRs apply to a CERCLA response, there are
several compliance alternatives: (1) comply  with the
LDR that is in effect, (2) comply  with the LDRs by
choosing one  of the LDR compliance alternatives
(e.g., Treatability Variance, No Migration Petition),
or (3) invoke an ARAR waiver (available only for on-
site actions).  As discussed previously, alternative
treatability variance levels  and technologies have
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been established for CERCLA soil and debris waste
that are restricted from land disposal under the
LDRs.

Applicability of RCRA Requirements to CERCLA
Cleanups-
The CERCLA Compliance with other Laws Manual
provides guidance on how to determine  which of
RCRA  requirements are applicable to CERCLA
actions. In general, RCRA  requirements  are
applicable to a  waste at a CERCLA site when two
conditions are satisfied: (1) the waste is a RCRA
hazardous waste, and (2) the waste is treated, stored,
or disposed of after  the RCRA  requirement is
effective. In general, RCRA is applicable to wastes
that were  disposed after  the effective date of the
RCRA Subtitle C requirements under consideration
(generally November 19, 1980), or to treatment,
storage, or disposal of hazardous waste that had been
excavated at a CERCLA site.


Placement—
If "placement" has not occurred, the RCRA disposal
requirements  are not applicable. EPA  uses the
concept of "areas of contamination"  (AOCs) to assist
in defining when "placement"  does  and does not
occur for CERCLA actions involving on-site disposal
of wastes.  An AOC is delineated by  the areal extent
of contiguous contamination. For on-site  disposal,
placement occurs when, wastes are  moved from one
AOC into  another AOC. Placement does not occur
when wastes are  left in place, or moved within a
single AOC.

CERCLA Substances vs RCRA Hazardous
Wastes-
Not all wastes  or substances at CERCLA sites are
RCRA hazardous wastes. Based on the information
gathered during a CERCLA site investigation, it is
determined whether the industrial source or
physical/chemical properties of the wastes present at
the site demonstrate that the CERCLA waste  is a
RCRA hazardous waste. For RCRA regulations to be
potentially applicable, there should be affirmative
evidence  (e.g., manifests, records, knowledge of
process) demonstrating that the CERCLA waste is a
RCRA hazardous waste. If such evidence does not
exist, the RCRA regulations are not applicable, but
may be relevant and appropriate if the waste is
sufficiently similar to a RCRA waste listed from a
specific industry or process.

To  determine whether a CERCLA waste is a RCRA
characteristic  waste,  site managers  may test the
waste or use their knowledge of the  properties of the
waste. To determine if a waste is a listed waste,
sampling  alone will not  be sufficient.  The RCRA
listing descriptions will generally require that the
site manager know the source of the waste or its
prior use.

Applicability of LDRs-
OSWER guidance [22] stipulates that for the LDRs
to be applicable, the CERCLA response action must
constitute placement of restricted RCRA hazardous
waste. Placement does not occur, and the LDRs are
not applicable if (1) wastes are treated in situ, or (2)
wastes are excavated, stored, and redeposited, all
within a single AOC, prior to treatment.

The LDRs do apply if excavated waste from an AOC
is placed in a separate unit, such as an incinerator or
tank that is within the AOC, and then treatment
residuals are redeposited  into the same AOC.
Therefore, if excavated  waste is pretreated (e.g.,
neutralized) prior to redeposition, the LDRs may be
applicable. The extent of waste preprocessing  that
triggers the LDRs is not well-defined at this time.

Conclusion-
Because  in  situ treatment does  not  involve
excavation or placement of the waste to be treated, it
appears that  RCRA  requirements  would  be
applicable only if the waste to be treated in situ was
found to be a RCRA hazardous waste, and the
hazardous waste was disposed after the effective date
of the RCRA  requirements. In these limited cases,
although stabilization/solidification is  considered
treatment under RCRA, most RCRA standards are
unit-specific design and operating standards, and do
not directly pertain to in situ treatment. The RCRA
requirements that are most likely to be ARARs for in
situ treatment of hazardous  waste are related to the
long-term management of the area treated, such as
requirements governing closure and post-closure. In
most cases, in situ treatment  in general will be
subject to site-specific cleanup standards.

If wastes  are  staged prior to solidifica-
tion/stabilization treatment, RCRA requirements
would apply  only if (1) the wastes were RCRA
hazardous wastes, and (2) the wastes were moved
outside the AOC for  storage or redisposal. In these
cases, additional applicable requirements  may
include design and operating standards for the land-
based unit, as well as the LDRs.

Toxic Substances Control Act (TSCA)

The disposal of PCBs and PCB-contaminated
materials, at concentrations of 50 ppm and greater,
and wastes resulting from uncontrolled discharges of
such materials, are regulated under the provisions of
the Toxic Substances Control Act of 1976. Materials
containing PCBs  at any concentration also may be
regulated under RCRA if mixed with RCRA waste.
The TSCA regulations, which are found in 40 CFR
761.60, address disposal requirements in relation to
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the concentration of the PCBs in the waste. PCBs in
concentrations  greater than 500 ppm must be
disposed by incineration. Wastes containing PCBs in
concentrations of 50 to 500 ppm may be disposed of
either by landfilling, incineration,  or an approved,
nonthermal alternative. These requirements are
potentially applicable to any waste containing PCBs,
even if other contaminants are present.

Several states and local governments may also have
their own PCB requirements. For instance, at the
Hialeah site, Dade County is requiring GE to  treat
soils that contain PCB concentrations of 1.0 ppm and
above.

TSCA Disposal Requirements for PCBs-
In section 761.3,  the TSCA  regulations define
"disposal" to include "any actions  relating  to
destroying, degrading, [or] decontaminating...PCBs
or PCB Items." Incinerators include rotary kilns,
liquid injection incinerators, cement kilns, and high
temperature boilers.  In addition to  approved
incinerators or other thermal devices,  under the
authority of section 761.60(e), EPA may  approve
non-thermal PCB disposal processes of "destroying"
PCBs with the same effectiveness as an approved
high-temperature incinerator.  EPA guidance [24]
indicates that an equivalent level of performance for
an  alternate method of treatment of PCB-
contaminated material is demonstrated if it reduces
the level of PCBs to less than 2 ppm measured in the
treated residual.  PCB wastes treated to this level by
an approved process are no  longer subject to the
TSCA requirements. Aqueous streams must contain
less than 3 ppb PCBs. Releases to air must be less
than 10 ug of PCBs per cubic meter.

TSCA disposal requirements do not generally apply
to PCB  wastes disposed in disposal sites prior  to
February 17, 1978,  the effective date of the  PCB
disposal regulations. The TSCA regulations do not
apply to the PCBs at the Hialeah site because
disposal occurred prior to the February 17, 1978 and
because the PCBs are not being removed, but instead
being treated in situ, without excavation. However,
if PCB waste disposed prior to  the effective date of
the regulations  is excavated,  the  waste must be
disposed in accordance with the PCB disposal
regulations.

TSCA Disposal Requirements and
Stabilization/Solidification-
Under the disposal requirements, bulk liquid waste
containing between 50 and 500 ppm of PCBs must be
pretreated and/or  stabilized  to  eliminate the
presence of free liquids prior to final disposal in a
TSCA-approved chemical landfill.  To date, no
stabilization/solidification process has been approved
as an alternative disposal method to incineration.
There are not currently any TSCA permitting
standards in place to guide  the  review of this
technology, in view of the difficulty in comparing
stabilization/solidification of PCBs with high-
temperature incineration. Consequently, Superfund
evaluates stabilization/solidification in terms of
employing the appropriate long-term management
controls consistent with chemical waste TSCA
landfill requirements.

Applicability of TSCA  Requirements to CERCLA
Cleanups-
The Superfund PCB Guidance is due to be published
in the spring of 1990. This guidance will clarify when
TSCA requirements  are ARARs for CERCLA
activities. In general,  TSCA disposal requirements
for  PCBs would be applicable to CERCLA activities
in two instances. If  PCBs were  disposed after
February 17,  1978,  the effective date of  the
requirements, TSCA disposal requirements would be
applicable to the waste, even if it is treated in situ.
Excavation of the PCB material for treatment or
disposal (such  as  staged  treatment) would also
trigger TSCA requirements, regardless of when  the
waste  was originally disposed.  Lastly,  if TSCA
requirements are applicable, it may be  difficult to
demonstrate  compliance with  the  use  of
stabilization/solidification alone, without subse-
quent disposal in a chemical landfill.

As with other hazardous substances, cleanup levels
for PCBs are generally established on a site-by-site
basis, considering local,  state, and  federal
requirements.  The  upcoming  Superfund PCB
Guidance will also provide guidelines on starting
point cleanup levels. The PCB Spill Cleanup Policy
(40CFR 761.120 through  761.139) gives cleanup
guidelines for most spills of PCBs greater than 50
ppm occurring after May 4, 1987. This policy gives
cleanup guidelines of 10 to 50 ppm for PCBs in soil,
depending on the location of the spill. The PCB Spill
Cleanup Policy  is to be considered  in determining
PCB cleanup levels at Superfund sites.


Waste Characteristics and  Their  Impact
on  Performance of the  Technology
Stabilization/solidification processes involve  the
addition of agents that are intended to mechanically
or chemically bind hazardous constituents to prevent
their release into the environment. These processes
usually increase the  strength and decrease  the
permeability of the solidified mass. In general,  the
stronger, more impermeable  and durable a treated
waste, the more effectively it  will contain hazardous
constituents.  If the material does not fragment,
create dust, or increase the surface area available for
leaching, losses will be  minimized.  Stabiliza-
tion/solidification processes are potentially effective
for some types of organics for both soils and sludges,
and have been proven effective for various inorganic
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wastes,  such as metals, asbestos and radioactive
materials.

The IWT/Geo-Con process used in Hialeah, Fla. is a
cement-based process, where the typical design
concept is  to solidify and  immobilize waste
contaminants. The principal differences between this
process  and  other cement-based ones are  that the
proprietary  additive is applied in situ and that
chemical bonding of the additive  to contaminants
may occur, which would contribute  to toxic
immobilization. The Geo-Con/DSM equipment has a
wide range of applicability. It can be used in most
soils, with a wide range of physical characteristics, to
depths in excess of 100 ft.

The IWT process is claimed to be applicable for
treatment of soils, sludges, solids  and liquids
containing a wide range of organic and inorganic
toxic compounds. IWT prefers to treat materials that
contain  less than  25  wt% organics, except for
refinery  wastes. For high  organic  wastes, larger
dosages  of additive would probably be required.
IWT's only field experience is at the Hialeah,  Fla.
site, where the organic content of the soil was very
low (<1.6 wt%). Its experience with high-organic-
content wastes consists primarily of laboratory tests
where some  posttreatment leach tests and chemical
bonding studies were performed, but  physical
property studies were  not  performed. Thus, very
limited proven experience with a variety of soils
exists, which would necessitate treatability studies
to confirm  anticipated performance for each
potential waste, especially  those high  in  organics
content.

Although an HWT-20 admix was selected for use at
the Hialeah site  for  the treatment of PCB-
contaminated soils, other formulations exist to treat
other contaminants. IWT is continuing to develop
new formulations  that  will  improve chemical
bonding and even degrade various organic  toxins to
less toxic compounds. Thus, the IWT additive may be
able to treat  a wide variety of solid and liquid wastes,
both organic and inorganic.

The Geo-Con/DSM equipment  can  operate in
virtually all types of soils. Clays, oily sands  and
cohesive soils may reduce auger penetration rate.
They may also limit the depth of operation to about
60 ft (due to the excessive torque required). This
depth should be well below any soil contamination at
most locations. In a non-cohesive soil,^ such as a
sandy loam, penetration rates up  to 6  ft/min have
been used by Geo-Con for grout injection. In cohesive
soils, the rate would probably be below 3 ft/min. The
primary limitations on  using the equipment (which
may be circumvented  by excavation at  shallow
depths)  and  special injection procedures at greater
depths, are caused by large rocks (>10 in.), lumber,
drums, etc. Another  factor that  could impact
operation is that a level surface is needed for the
DSM equipment.

A small enclosed site (smaller than the Hialeah site)
may also provide  difficulties of site access for the
auger injection system. To ease this  difficulty, the
additive preparation system can be erected remote to
the DSM equipment. This may also allow for its
operation in a clean zone. However, the larger the
distance between  the two parts of the system, the
more likely that slurry plugging of the transfer lines
could occur, the more energy would be consumed and
the more difficult would be the communications to
coordinate activities.

Subfreezing temperatures may impact the process in
two ways:

  •  IWT - The cement hydration reactions are
     usually affected by temperatures below 40°F,
     causing a poor quality product. This may be
     overcome in some circumstances by special
     cements or by preheating the additive stream to
     40 to 50°F.

  •  Geo-Con - Low temperatures may cause slurry
     freezing in the pipe lines between preparation
     and the auger injection nozzles; operations have
     been successful down to a temperature of 10°F.
     In very severe cold — well below 0°F — inability
     to penetrate the frozen earth may cause
     operational stoppage.

Typically, cement-based stabilization/solidification
systems have the  following potential limitations to
their effective use:

  •  Organics content above 45 wt%. This limitation
     may not apply to  the IWT additives because
     they contain organophilic clays that may help
     in the immobilization reactions.

  •  Wastes with less than 15 wt% solids.

  •  Excessive quantities of fine soil particles (< 74
     um) and excessive large particles (>0.25 in.)

  • 'Various  chemicals may retard  setting o.r
     interfere  with cement bonding,  such as:
     phenols;  halides;  cyanides; soluble salts of
     manganese,  tin, zinc, copper,  and  lead;
     arsenates; borates; and some others.

  •  Sulfates could cause swelling  and spalling of
     the cement.

  •  VOCs may be driven off by the heat of the
     hydration for the cement reactions.
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Acidity of the soil  or sludge  should not  present
problems, as cement is highly alkaline. In addition,
lime  could  be added  to  provide additional
neutralization potential.  The ability  of the HWT
additives to overcome the above listed potential
problems has not been addressed by the developer.

Material  Handling  Required  by  the
Demonstrated Technology
A successfully treated product  from the IWT/Geo-
Con in situ  stabilization/solidification  system
depends on proper weight, flow  calibrations, and
ratios of the admixes. Component feed variations,
such as "slugs" of oil and grease in an otherwise
uniform soil, may present some difficulties.  In order
to overcome this disadvantage, if this is a frequent
occurrence, the process is capable of using higher-
than-required admix ratios. However, this procedure
is less cost effective. The primary advantage of in
situ operation is that excavation and transporting of
the contaminated soil is not necessary.

For in situ treatment, heavy equipment is required
to  properly inject and mix the additives with the
waste. Both in situ and waste-excavated systems for
above-ground treatment require air monitoring
equipment to track organic and dust exposures
during injection, excavation, transport and feed to
the system. Contaminated water, whether surface or
groundwater, can be used in the process as the water
additive.

The materials handling associated with the Geo-Con
DSM consists of a slurry preparation system, usually
remote from the injection  auger and in a  non-
contaminated area. Thus, a slurry has to be pumped
a considerable and variable  distance to reach the
auger. Since a 57-wt% solids slurry is being handled,
the design must prevent solids settling to avoid line
plugging. The front-end of the slurry preparation
area has less potential for difficulties, and it consists
of feeding a storage  silo by an air-conveying system
from the supply truck. From the silo, a calibrated
rotary valve is used to feed  the slurry preparation
system. This  slurry preparation is batch operated,
but could be designed for  continuous operation also.
To  confirm that the correct amount of water and
additive was added to the slurry tank, the density of
the slurry is measured onsite by a mud balance.

Personnel Issues
Eleven people are required for the 1-auger and 13 for
the 4-auger Geo-Con/DSM  units.  This includes
operators, supervisors, health and safety officer, plus
office personnel and a sampling technician. This is
based on a one-shift-per-day operation. These people
must pass appropriate physical exams and have
completed an approved 40-hour hazardous-materials
training course.

Personnel are subjected to the standard  OSHA
requirements for operating moving equipment and
would be required  to wear the proper personal
protective equipment dictated by the specific site
conditions  and  contaminants.  Personnel have
minimal  contact with the waste, as all streams are
remotely handled, except during decontamination
and  maintenance.  This is also  true for many
remediation processes.

Procedures for Evaluating
Stabilization/Solidification
Critical parameters in stabilization/solidification
include the selection and quantity of additive, plus
mixing and curing conditions [25]. These parameters
depend on the chemical and physical characteristics
of the waste. Bench-scale treatability tests should be
conducted to select the proper additives, quantities
and curing  times. Therefore,  chemical analyses of
the waste should be performed using EPA accepted
procedures [26], to define the type  and quantity of
contaminants, along  with leach tests to  obtain
untreated leachate concentrations. After waste
treatment, the leach tests should be repeated, as well
as unconfined compressive strength tests. This would
be the  minimum of tests performed.  If time and
money are available, moisture content, bulk density,
and weathering tests should be added.

For evaluating the  IWT/Geo-Con process, a more
complete sampling program was  defined  in  the
Demonstration  Plan. The samples taken and
analytical procedures used were selected based on
the information required to provide answers to the
technology evaluation criteria. The two important
technical criteria to evaluate  any stabiliza-
tion/solidification technology are: immobilization of
the contaminants, and durability of the solidified
mass. Tests were drawn from various related fields
and applied to the hazardous waste to obtain the
answers. Other tests, such as acid neutralization and
specific gravity, also could have been performed as
part of the evaluation. The most important factors in
evaluating contaminant mobility are:

  •  To relate pretreatment to posttreatment results

  •  To measure contaminant concentration in the
     waste for the samples being used in leaching
     tests

Therefore, for both pretreatment and posttreatment
samples, soil  samples were  analyzed for PCBs,
VOCs, and heavy metals before samples of the same
material were leached. The TCLP  test is  the most
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widely accepted procedure and is the basis for
proposed regulatory levels for organics and heavy
metals. It is the most important test in the program
for evaluating contaminant mobility. Two additional
leach tests, MCC-1P and ANS 16.1, also were used on
selected  posttreatment samples; they attempt to
evaluate  leaching from a solidified mass. MCC-1P
simulates a quasi-static groundwater regime in
contact  with  the  waste where  saturation
concentrations may be approached, and ANS 16.1
simulates a more-rapidly moving  groundwater
where saturation is not reached. These tests  were
drawn from the nuclear industry and are relatively
expensive  to perform. They  also use different
leachate-to-solid ratios compared to the TCLP test
and to each other, so only a qualitative relationship
between test results is valid.

Following the TCLP  test, the next most important
test is permeability, which  is a measure of flow of
water through the solid. Since water is the  leaching
agent,  only water coming in contact with the
contaminants can leach the toxins  out. A constant-
head permeability test - such as ASTM D-2434-68 -
can be used for untreated soils where permeabilities
are relatively high, more than  10-4 cm/s.  For the
treated soils — where permeabilities may range from
10-6 to 10-8 cm/s - the falling head permeability test
is used.  This  is described in Test Methods for
Solidified Waste Characterization (TMSWC) [27].

Once the contaminant is immobilized, the main
concern  is how long  it will  remain that  way.
Therefore,  tests  were performed to provide
information on  potential durability of the treated
soil.  In addition, testing must include a long-term
monitoring program — for this SITE project a 5-year
period — in which samples are collected from the
treated soil that has been exposed  to the weather.
The most prominent  test is UCS, which provides a
measure  of the quality of the solidified mass. It is a
test commonly used by the  cement industry and is
relatively inexpensive.

Wet/dry  and freeze/thaw 12-cycle tests  provide
additional information on degradation of the
solidified material. The tests used  are described in
TMSWC  and are very  similar to the ones  used by
ASTM. These tests  provide an indication as to
whether  the solidified material, when saturated or
near saturation (such as occurs with a high water
table), will disintegrate over the first few weathering
cycles,  which may  take place within  the first  year.
The tests cannot be used to predict the  life of the
solidified mass in terms of decades or centuries.

The final group of tests, which can be performed and
interpreted at only a few laboratories, go under the
general heading of microstructural analyses.  Both
treated-soil samples and a few untreated ones are
analyzed by the following methods:

  •  X-ray  diffraction  (XRD)  -  This  defines
     crystalline structure, which can indicate
     changes from the normally expected structure.

  •  Microscopy - both optical and scanning electron
     microscopy  (SEM).  These techniques
     characterize  crystal  appearance,  porosity,
     fractures and the presence of unaltered waste
     forms. From these observations, mixing
     efficiency can sometimes be estimated.

  •  Energy-dispersive X-ray spectrometry - This
     can determine elemental analysis of crystal
     structures and hence composition.

These tests  are proven analytic methods for
understanding the mechanism  of  structural
degradation in materials similar to those of the
demonstration. The  literature  is  replete  with
examples of SEM and XRD analyses of soil, cement,
soil-cement mixtures, and each of these mixed with
various inorganics  and  organic compounds.
However, there have been relatively few  studies  of
the microstructure of complex  waste/soil  mixtures,
such as those resulting from  a  stabiliza-
tion/solidification procedure. Consequently, in some
cases,  interpretation of the  microstructural
observations may be difficult.

These microstructural data provide  information on
the potential for long-term durability of the solid.
They cannot quantitatively predict  the life of the
solid mass or provide a direct relationship to results
from the other tests described above.  In the future, if
a body of data is  developed  from  long-term
monitoring programs, the  predictability of and
interrelationships among these procedures will
improve.

Another test of importance, but one not directly
related  to the two technology evaluation criteria
(immobilization and durability),  is the  inexpensive
test of measuring bulk density. In all solidification
processes, pozzolans and special additives,  along
with water in many cases, are added to the waste.
These could result in major waste  or soil volume
changes,  which may  affect  the  remediation
procedures. Bulk density measurements of the soil
before and  after treatment,  along with a  material
balance, will provide a method of calculating volume
change during the remediation process.

The other physical tests - moisture,  pH  and particle
size distribution (PSD) — are typical soil tests and
provided background information that could become
important if problems occur. Moisture and pH tests
are very inexpensive and a PSD is moderately priced.
                                                23

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                                           Section 4
                                     Economic Analysis
Introduction
A primary purpose of this economic analysis is to
attempt to estimate costs (not including profits) for a
commercial-size remediation. It is assumed for this
analysis, which is based on the test at Hialeah, that
part of a large Florida site is to be remediated. Many
costs are site specific, being affected by such factors
as: site geology; type and quantity of contaminants;
proximity to the community or to other industrial
sites;  regulatory requirements; and local costs of
labor, utilities and  raw materials. The analysis
assumes that the remediation occurs in Florida in a
spacious, rural setting, and  it simplifies  and
eliminates some potentially expensive site-specific
costs.

Due to the short-term nature of the demonstration
and the fact that labor, equipment  rentals and
chemical expenses dominate the remediation costs,
the actual costs for Geo-Con and EPA were not used.
However, Geo-Con provided information from its
quotation to GE and this was used as a basis.
Information was provided for a 1-auger machine for
the demonstration, and a 4-auger unit that would be
used for a larger application, such as  the complete
remediation of the GE site.

Many actual or potential costs exist that are not part
of this estimate.

The major items are as follows:

   • At the site  a prime contractor performs  many
     functions, including some  services not shown,
     or only partially included in this cost estimate.
     This includes site preparation, such as building
     roads, providing access to the treatment area
     and providing utilities to plant battery limits.
     Battery limits can be defined as the  limits of a
     space envelope that includes all of the Geo-Con
     equipment  plus support equipment to which
     utilities and access must be provided.

   • The treated waste has a  greater volume then
     the untreated waste. Thus, the treated waste
     will cause the  ground surface  to  rise, the
     amount depending on  the  depth  of the
     treatment operation. The cost of removing
     excess  material to a landfill could be  quite
     substantial and is not included.

Even if the excess is  moved to another part of the
site, or if it is left in place, land contouring would be
required at some expense. Depending on the option
required, appreciable  variations in these costs may
be encountered.

   • Permitting, and  environmental monitoring of
     operations for regulatory authorities are not
     included.

   » Operations are assumed to be 5 d/wk and 8 h/d.
     Any changes in this schedule would change the
     remediation cost. For example, 24 h/d operation
     would reduce it, by  decreasing the labor and
     equipment rental costs.

   • Treating an  oily waste requires an  increased
     additive ratio, possibly 0.25 Ib HWT-20/lb dry
     soil or more, instead of the usual value of 0.15 Ib
     HWT-20/lb  dry soil. This  would  increase
     operating costs by about $34/ton.

The results are presented in Table 2.

Results of Economic Analysis

The results  of the analysis show the  approximate
cost per ton for the 4-auger application is $111 and
for the 1-auger application is $194. Some items
mentioned in the  previous subsection and discussed
in more detail  under Basis of Economic  Analysis,
could increase the cost. Extreme care in defining any
ground rules for the economic analysis is required.

The results  show that 85% of the costs are for raw
materials (HWT-20),  equipment rental and labor.
IWT estimated the cost of HWT-20 at $380/ton. All
costs are  site-specific; on the west coast the cost
might be 20% greater. Labor costs include 10 people
to operate the 4-auger unit, and 8 people for the 1-
                                                 25

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                 Table 2. Estimated Cost (a,b), S/Ton
                                                          4-Auger system
                  1 -Auger system
                 Site Preparation
                 Permitting and Regulatory
                 Equipment
                     Geo-Con, $ (c)                           801,000            77,000
                     Equipment rential + subcontractors             26.23              67.90
                     Consumables                               6.94.              19.29
                     Contingency (10% of direct costs)               1.18               0.45
                 Start-Up and Fixed Cost
                     Operator training                            0.45               0.31
                     Site mobilization                      ,       0.90               0.31
                     Depreciation (10% of direct costs)               1.18               0.45
                     Insurance and taxes (10% of direct costs)          1.18               0.45
                 Labor Costs
                     Salaries and living expenses                   15.38              45.73
                     Administration (10% of direct costs)              1.18               0.45
                 Supplies - Raw Materials
                     IWT additive, HWT-20                       52.45              52.45
                     Sodium silicate                              0.23               0.23
                 Supplies - Utilities
                     Fuel ($1.00/gal)                             0.90               2.16
                     Electricity ($0.04/kWh)                        0.06               0.21
                     Water ($0.80/1,000 gal)                       0.02               0.02
                 Effluent Treatment
                 Residual Transport
                 Analytical                                      1.14               3.28
                 Facility Modification  (10% of direct costs)              1.18               0.45
                 Demobilization                                  0.90               0.31
                 Totals	111.50	194.45	

                Notes
                (a)  This does not include profits of the contractors.
                (b)  The American Association of Cost Engineers defines 3 types of estimates: order of magnitude,
                    budgetary, and definitive. This estimate would most closely fit an order-of-magnitude estimate,
                    with an accuracy of +50 to -30%. However, this being a new technology, the range on the
                    potential accuracy may be significantly wider.
                (c)  Not used directly, but used for the estimate of other costs.
auger machine. In addition, 3 people are assumed for
purchasing, administration, and sampling.

The largest cost savings in remediating the site
results from  using the  4-auger  DSM  unit, which
would reduce operating time, thus saving both  labor
costs and equipment  rentals. The next-largest cost
factor is the additive, which is being used at a rate of
15  lb/100 Ib of dry waste. This value  is near the
minimum, and could increase significantly for hard-
to-treat wastes, such as those high in oil and grease.

Basis of Economic Analysis

The costs analysis is prepared by breaking the  costs
into 12 groupings. These will be described in details
as  they  apply  to the IWT/Geo-Con  in  situ
stabilization/solidification process. The categories,
some of which do not have costs associated with  them
for this technology are as follows:

   • Site preparation costs — including site design
     and  layout, surveys and site investigations,
     legal searches, access rights  and  roads,
   preparations   for   support   facilities,
   decontamination facilities, utility connections
   and auxiliary buildings.

•  Permitting and regulatory costs  — including
   permit, system  monitoring requirements, and
   development of monitoring and analytical
   protocols and procedures.

•  Equipment costs. Broken out by  subsystems,
   including all major equipment items — process
   equipment, materials handling equipment and
   residual handling equipment. Also includes
   descriptions  of the equipment specifications
   (i.e., throughput and utilization rate).

•  Startup and fixed costs.  Broken  out  by
   categories, including mobilization, shakedown,
   testing, working capital, depreciation, taxes,
   and initiation of environmental monitoring
   programs.

•  Labor costs.  Including  supervisory and
   administrative staff, professional and technical
                                                    26

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     staff,  maintenance personnel,  and clerical
     support.

  •  Raw materials. HWT-20 and sodium silicate.
     This is the largest of the 12 cost categories for
     the IWT/Geo-Con technology, and any design
     optimizations based on treatability studies  or
     direct field  experience could have a large
     impact on the bottom line.

  •  Supplies and consumables.  Includes utilities,
     such as fuel, electricity,  and water,  and
     posttreatment of the  treated  soil and  any
     byproducts.

  •  Effluent treatment and disposal. Both onsite
     and offsite facility costs, including wastewater
     disposal and monitoring activities.

  •  Residuals and  waste shipping, handling, and
     transport.  Including the  preparation for
     shipping and actual waste-disposal charges.

  •  Analytical. Including laboratory analyses for
     operations and environmental monitoring.

  •  Facility modification, repair, and replacement
     costs.  Including design adjustments,  facility
     modifications, scheduled maintenance,  and
     equipment replacement.

  •  Demobilization. Including shutdown, site
     cleanup and restoration, permanent storage
     costs, and site security.

The  estimates are based on the  following general
assumptions:

  •  The remediation occurs at a large, rural Florida
     site.

  •  A total of 38,400 tons of soil, containing 8 wt%
     moisture, is processed  in each of the two cases
     estimated. This figure  assumes that 50,000 ft2
     is treated to a uniform depth of 16 ft, with the
     soil density the same as the GE site, 96 lb/ft3.

  •  Although there was a prime contractor onsite,
     this cost is not included. The  contractor
     provided certain functions for the IWT/Geo-Con
     processing unit, such as site preparation.

  •  Many  of the  cost estimates were provided by
     Geo-Con [28].

The twelve  cost factors, along with the assumptions
utilized for each, are described below.

  •  Site preparation costs. It is assumed that this
     work will be performed by the site prime
     contractor and that there will be no charges  to
  this cleanup. This assumes that roads,  site
  preparation for the Geo-Con DSM machine and
  its support equipment,  and access to  the
  feedstock are provided by others, along with the
  supply of electricity and water to battery limits.
  It also assumes that any final contouring of the
  land  will also be performed by the prime
  contractor.

• Permitting and regulatory costs. It is assumed
  that  this hypothetical  Florida  site  is  a
  Superfund site, so no permits will be required,
  either federal or state. The need for developing
  analytical protocols or monitoring  records  is
  assumed not to exist. On non-Superfund sites,
  this activity could be expensive and very time
  consuming.

• Equipment costs. Based  on  information
  provided by Geo-Con, the capital cost for the  1-
  auger machine is $77,000 (plus some equipment
  rentals) and $801,000 for the 4-auger machine.
  Of these  total costs, the mixing plant  was
  approximately $50,000 and is the same for both
  units. Equipment rental costs and subcontract
  costs  were provided by Geo-Con, and (with some
  adjustments) were $26.23/ton and $67.90/ton
  for the 4-auger and 1-auger units, respectively.
  Geo-Con's profit was estimated  so  that their
  quotation values  could be converted to costs.
  Additional items -- such as  fuel, sodium silicate,
  water storage, fences, and lighting --  are
  assumed to be provided by  the prime contractor
  and are not included in these  remediation costs.

 , The equipment rental and subcontracts are one
  of the largest operating costs. Rental equipment
  includes such items as front-end loaders, back-
  hoes for soil excavation and  transport, a steam
  cleaner for decontamination, a pickup truck, a
  drill rig, a crane  and personnel facilities.  The
  subcontracts include such items as trucking,
  piping and electrical hookup.

  Consumables are also included in this group,
  and include expendable  health and safety
  clothes, health and  safety  instrumentation,
  trailers for office space,  sanitary  facilities,
  lights and sampling materials. Geo-Con
  provided a cost for consumables of $9/yd3 for the
  4-auger machine  and  $25/yd3 for the 1-auger
  machine.

  Since some additional equipment is required for
  this hypothetical site compared to the GE site,
  and Geo-Con's  values include profit,  the
  analysis assumed that these dollar values
  balanced and that Geo-Con's quotation was to
  be only costs.
                                                27

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  A contingency cost, approximately 10% of the
  direct costs on an annual basis, is allowed for
  unforeseen or improperly defined costs. This is
  separate from the previously described design
  basis uncertainties.

• Startup and fixed costs. The costs included in
  this group  are operator  training, initial
  shakedown of the equipment, equipment
  depreciation, insurance and taxes. The labor
  costs and living expenses for mobilization,
  operator training, and initial shakedown of
  equipment are estimated from Geo-Con's total
  labor-cost quotation.

  It is assumed  that 5 days of training are
  required  for   the  Geo-Con  operators,
  supplementary field personnel, the site health
  and safety officer and the sampling technician.
  The costs include  salaries,  overheads and
  expenses at the rates described below for labor.

  Initial startup includes setup  of the  Geo-Con
  equipment and  checkout of its operation. One
  week is allowed for this site mobilization, but
  travel costs to the Florida site are not included.
  The installation of any support tankage,
  pumps, etc., is not assumed as a charge to the
  remediation. This is probably a modest cost,
  equivalent to a  few dollars per ton, but the
  design of a system and a budgetary or detailed
  estimate of it  is outside  the scope of this
  economic analysis.  For  purposes of this
  estimate, this installation work is assumed to
  be by the site prime contractor  and not charged
  directly to the IWT/Geo-Con operation.

  The depreciation costs are based on a 10-yr life
  for all equipment. Costs are based on the write-
  off of $77,000 worth of equipment for the 1-
  auger system and  $801,000 for the 4-auger
  system.

  Insurance and taxes are lumped together and
  are assumed to be 10% of direct costs taken on
  an annual basis.

• Labor costs. These costs  are salaries plus
  overhead, along with living expenses  and some
  miscellaneous administrative expenses. It is
  expected that  a total of 13  people will be
  required for the 4-auger unit and 11 people for
  the 1-auger unit. It is expected that most of the
  people will  be on expenses, except  for the 3
  support people who are assumed to be local
  hires.

  Geo-Con indicated they require a total of 10
  people for the 4-auger machine and 8 people for
  the 1-auger unit. It is also assumed that there is
  1 office manager at $30/h, 1 secretary at $16/h,
  and 1 sampling  technician at $25/h. These 3
  people are assumed to be locally hired and not
  on an expense account. The costs — which are
  provided by Geo-Con and include  startup and
  operating training (after correcting for profit) —
  are $13.20/ton of waste for the 4-auger unit and
  $37.02/ton of waste for  the 1-auger  unit. All
  these costs are assumed to include a 10% to 15%
  contingency that allows  for overtime and
  unexpected  expenses. The values shown in
  Table  2 include the  3  additional people
  described above.

  An additional labor-related expense item is
  administrative  costs,  which include office
  expenses,  such as supplies, telephones,
  furniture, and reproduction equipment, but not
  salaries. This cost is assumed to be 10%,  on an
  annual basis, of direct costs.

• Supplies and consumable costs - raw materials.
  This cost group includes typical variable costs
  and is the largest expense for the 4-auger unit.
  The raw materials are the IWT additive, HWT-
  20, and sodium silicate. The cost  for HWT-20
  was provided by IWT. The HWT-20 was
  charged  to the project at $380/ton delivered to
  the Florida location. The HWT-20 was assumed
  to be used at a rate of 0.15 Ib/lb dry soil with the
  soil at an average moisture content of 8 wt%.
  The sodium silicate is assumed to  be added for
  the bottom 3 ft at 5% of the rate for the HWT-
  20. The cost of sodium silicate,  based on a
  verbal quotation from a supplier, is $0.0885/lb.

• Supplies and consumable costs — utilities. The
  utilities included are fuel, electricity and water.
  Also included are  byproducts that require
  treatment or transport to a landfill. The latter
  item does not apply to this economic analysis,
  since no byproducts are produced.

  It was  estimated  that the  total  fuel
  consumption for  the 4-auger system, for the
  crane and all the associated vehicles is  200
  gal/d, and for the 1-auger system, is 140 gal/d.
  External electricity is  not required for this
  equipment. The fuel was assumed to cost
  $1.00/gal.  Electricity is  assumed  to power
  lights, trailers,  etc., at an assumed average
  daily-rate of 10  kW. The cost of electricity is
  assumed to be $0.04/kWh.

  Water use is primarily for the process, with 500
  gal/d assumed for equipment decontamination
  and other miscellaneous requirements. Based
  on a material  balance  that assumes  the
  untreated soil contains  8% moisture and the
  treated soil has  18% free  moisture plus water
                                              28

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  for cement hydration, the water consumption is
  approximately 14.2 gpm for the large unit and
  4.3 gpm for the smaller unit. The cost of water
  is assumed at $0.80/1,000 gal.  There are no
  byproducts from the  IWT process, and soil
  pretreatment or posttreatment is not necessary.

• Effluent  treatment and disposal costs. Since
  there are no liquid effluent streams associated
  with this technology,  no costs accrue to this
  category.

• Residual and  waste shipping,  handling and
  transport costs. There are no residuals or
  byproducts associated with the IWT technology.
  Therefore, there are  no expenses associated
  with this category of potential costs. However,
  if this changes due to the inability of the site to
  handle the volume increase produced in the
  treatment of the wastes, a major new  expense
  for transporting the excesses to an approved
  landfill would occur.

• Analytical costs. It is assumed that  sample sets
  will  be taken daily for the first two weeks of
  operation. After  that, samples will  be collected
  once a week until the cleanup is  completed.
  Both physical and chemical analyses will be
  run  on all  samples, with the  cost per  set
  approximately $1,200. The cost/ton reported in
  Table 2 is an overall average value, based on a
  completed project.

• Facility modification, repair and replacement
  costs. The costs accrued under this category
  include maintenance and working capital.
  Maintenance materials and  labor costs  are
  difficult to estimate and cannot be predicted as
  functions of preliminary design concepts.
  Therefore,  annual maintenance costs  are
  assumed as 10% of capital  costs. Working
  capital costs are assumed to be negligible, as all
  supplies  purchased to* have  on-hand  are
  assumed to  be fully consumed by the project's
  completion.  The cost of using money early in
  the project is neglected.

• Demobilization costs. It is assumed that all
  personnel will  be onsite for one week  for
  demobilization. This is sufficient time  for
  disassembly  of the Geo-Con  equipment,
  decontamination and cleanup. Any additional
  work  required  to return  the  site   to
  pretreatment condition, is assumed to be done
  by the site prime contractor and is not charged
  to the IWT process.
                                              29

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                                        References
1.   Report of Initial Bench Scale Testing
    Solidification/Fixation Agent Evaluation, Law
    Environmental,  Inc., a division  of Law
    Engineering Testing Co., Marietta, Ga. Report
    for General Electric Co., August 1986, Case
    Study D-l.

2.   Data Sheets from Southwestern Laboratories to
    Law Environmental, Inc., a division of Law
    Engineering Testing Co. (for GE),  May 1988,
    Houston, Tex., Case Study D-3.

3.   Prohibition on the Placement of Bulk Liquid
    Hazardous Waste Landfills  --  Statutory
    Interpretive Guidance. EPA  530-SW-86/016.
    OSWER, Washington, D.C., 1986.

4.   Guide to the Disposal of Chemically Stabilized
    and  Solidified Waste. SW-872 Revised.
    Municipal   Environmental   Research
    Laboratory,   Office  of Research  and
    Development, Cincinnati, Ohio, 1982.

5.   Tittlebaum, M.E., et  al.,  State of  the  Art
    Stabilization  of Hazardous Organic Liquid
    Wastes and Sludges, CRC Critical Review in
    Environmental Control, Vol. 15, Issue 2, CRC
    Press, Boca Raton, Fla., 1985, pp. 179-211.

6.   Sheriff, T.S., et al. Modified Clays for Organic
    Waste  Disposal. Environmental Technology
    Letters, Vol. 8, pp. 501-504,1987.

7.   Demonstration   Test  Plan   In  Situ
    Stabilization/Solidification  of   PCB-
    Contaminated Soil, USEPA,  1988, RREL,
    Cincinnati, Ohio.

8.   Evaluation   of   Test   Protocols   for
    Stabilization/Solidification Technology
    Demonstrations. Draft Report. Planning
    Research Corp., 1988. Contract 68-03-3484.
    USEPA, RREL, Cincinnati, Ohio.

9.   Presentation of the HWT Chemical Fixation
    technology and Japanese In-Place Treatment
     Equipment, Informal Document Issued by IWT,
     1986, Wichita, Kan.

10.   Advanced Chemical Fixation of Organic and
     Inorganic Content Wastes, Informal Document
     Issued by IWT, 1988, Wichita, Kan.

11.   Gibbons, J.J., and R. Soundararajan. The
     Nature of Chemical Bonding Between Modified
     Clay  Minerals and Organic Waste Materials,
     American Laboratory, 7/88.

12.   Technology Evaluation Report: SITE Program
     Demonstration Test, International Waste
     Technologies    In    Situ    Stabiliza-
     tion/Solidification,  Hialeah,  Florida,
     EPA/540/5-89/004a, June 1989.

13.   In Situ Stabilization/Solidification—Results of
     Split Samples Analyses.   Letter Report,
     Enviresponse, Inc. to USEPA, Edison, N.J.,
     EERU Contract No. 68-03-3255,10/6/87.

14.   Report of Chemical and  Physical Laboratory
     Analyses for Bench  Scale  Specimens, GE
     Service Shop, Hialeah, Fla. Letter Report, Law
     Environmental Service to General Electric Co.,
     10/10/86, Marietta, Ga., Case Study D-2.

15.   Cote, P., et al. An Approach for Evaluating
     Long-Term Leachability from Measurements of
     Intrinsic  Waste Properties, Hazardous and
     Industrial Solid Waste Testing and Disposal,
     6th Vol., ASTM STP 933, Dr. Lorenzen, et al.,
     Editors, ASTM, Philadelphia, Pa., 1986, pp. 63-
     78.

16.   Are We  Cleaning Up? Ten  Superfund Case
     Studies-A Special Report.  OTA-ITE-362. U.S.
     Government Printing Office, Washington, D.C.
     U.S.  Congress,  Office  of  Technology
     Assessment, 1988.

17.   CERCLA Compliance with Other Laws Manual
     (Draft), USEPA, OSWER Directive 9234.1-01,
     8/18/88, Washington, D.C.
                                             31

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18.  Superfund LDR Guide #1, Overview of RCRA
    Land Disposal Restrictions (LDRs), USEPA
    Directive: 9347.3-01FS, July 1989.

19.  Superfund LDR Guide #2, Complying with the
    California List Restrictions  Under Land
    Disposal Restrictions  (LDRs), USEPA
    Directive: 9347.3-02FS, July 1989.

20.  Superfund  LDR  Guide  #3,  Treatment
    Standards  and  Minimum  Technology
    Requirements  Under  Land  Disposal
    Restrictions (LDRs), USEPA Directive: 9347.3-
    03FS, July 1989.

21.  Superfund LDR Guide #4, Complying with the
    Hammer Restrictions Under Land Disposal
    Restrictions (LDRs), USEPA Directive: 9347.3-
    04FS, July 1989.

22.  Superfund LDR Guide #5, Determining When
    Land Disposal Restrictions (LDRs) are
    Applicable to CERCLA Response Actions,
    USEPA Directive: 9347.3-05FS, July 1989.

23.  Superfund LDR Guide #6A, Obtaining a Soil
    and Debris Treatability Variance for Remedial
    Actions, USEPA Directive: 9347.3-06FS, July
    1989.

24.  Draft Guidelines for Permit Applications and
    Demonstration Test Plans for PCB Disposal by
    Nonthermal Alternate  Methods,  August 21,
    1986, USEPA  Office of Toxic Substances,
    Chemical Regulation Branch, Washington,
    D.C.20460.

25.  Technology Screening Guide for Treatment of
    CERCLA Soils and Sludges, EPA/540/2-88/004,
    9/88, OSWER, Washington, D.C.

26.  Test Methods for Evaluating Solid Wastes,
    USEPA/OSWER, SW-846, Third Edition, 11/86.

27.  Test  Methods  for  Solidified  Waste
    Characterization, Draft Report, Environment
    Canada, 1985.

28.  Deep  Soil  Mixing for Stabilization  of
    Contaminated Soils, Hialeah, Fla.  Letter from
    Geo-Con, Inc. to Enviresponse, Inc., 8/30/88,
    Pittsburgh, Pa.
                                              32

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                                         Appendix A
                                    Process Description
Description  of  the  Primary  Treatment
Mechanisms

Solidification and  stabilization are treatment
processes that are designed to accomplish one or
more of the following results [1,2]:

  •  Improve  the  handling   and   physical
     characteristics of the waste, as in the sorption of
     free liquids

  •  Decrease the surface area of the waste mass
     across  which  the  transfer or  loss  of
     contaminants can occur

  •  Limit  the solubility of  any hazardous
     constituents of  the  waste,  e.g., by  pH
     adjustment or sorption

  •  Change  the chemical  form  of the hazardous
     constituents to render them innocuous or make
     them less leachable.

Solidification  entails obtaining  these results
primarily by producing a monolithic block of treated
waste with high structural  integrity. Stabilization
techniques limit the mobility of waste contaminants
or detoxify   them,  whether or  not the  physical
characteristics of the  waste  are changed  or
improved. This is accomplished usually through the
addition of materials to  ensure that the  hazardous
constituents are maintained in their least  mobile or
least toxic form [3].

One goal of treating hazardous wastes is removal of
the particular waste  compound or compounds from
the hazardous waste category; this process is  called
delisting.  Delisting of stabilized/solidified waste is
possible  upon the   demonstration to EPA's
satisfaction that the component or characteristic for
which  the waste originally was listed:   (1) is no
longer present in the treated  product; (2)  no longer
exhibits the characteristics  of the original waste; or
(3)  contains  the contaminants exclusively  in  an
immobile form.  This  determination of  the
nonhazardous character of the waste product makes
possible the less expensive and less rigorous disposal
of the wastes in any solid waste landfill.

Treatment Process Flow

In the IWT in situ stabilization/solidification process
the contaminated material is mixed with water and a
cement-based proprietary additive called HWT-20.
The developer (IWT) claims the contaminants bond
to the additive, as well as producing a cohesive mass,
thus immobilizing the contaminants.

A batch mixing plant prepares and feeds the
additives (see Figure A-l). HWT-20 is conveyed from
a supply truck by air to a storage silo. A measured
amount of water is fed to a mixing tank, and HWT-20
is added at a weight ratio of about 4/3 to water. A
positive displacement pump then feeds the slurry to
the drill rig. The HWT-20 feed rate is nominally 15
Ib dry additive/100 Ib dry soil but may be greater for
difficult applications, such as oily sludges.

Supplementary water is fed to the drill rig on a ratio
basis to  the slurry.  This ratio varies with soil
moisture  content.  At Hialeah  this was based on
being above or below  the water  table. The final
soil/HWT-20/water slurry is targeted to contain
approximately 1.6 to 1.7 Ib water/lb HWT-20.

The  control system for  the Geo-Con equipment
consists of the following:

  •  Water totalizer for flow to the slurry mix tank

  •  HWT-20 rotary feeder between the storage silo
     and mix tank

  •  Magnetic flow meter for measuring slurry flow
     to the drill rig

  •  Flow totalizers for supplementary water

  •  Instrument package that controls the ratio of
     slurry feed to the drill  rig auger penetration
     rate and water-to-slurry feed ratio
                                               33

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                                                                                             Pump
                                                                                             Valve
                                                                        Flow Line •
                                                                      Control Line	

                                                                Communication Line	
Figure A-1.   Batch mixing plant.

The Geo-Con/DSM system of mechanical mixing and
injection consists of 1 set of cutting blades and 2 sets
of mixing blades attached to a vertical drive auger.
The blades rotate at approximately 15 rpm. Two
conduits are constructed inside the drive rod and
injection ports are provided at the bottom of the
shaft, so that the additive slurry and water can be
injected into the zone being agitated by the rotating
blades. To create a vertical column of treated soil, the
blade is advanced to the desired maximum depth of
treatment.  The  HWT-20  additive is  injected in
slurry form and mixed into the soil and limestone as
the blade is rotated during entry into the soil, and is
mixed  again on withdrawal from  the  ground.  As
necessary, additional cycles of injection and mixing
are made along the length of the column to provide
the required blending. Column  positioning is
planned so that the columns  overlap, and all the
ground in the target area is affected (see Figure A-2).
The diameter of the  treated soil  column is
approximately 36 in. The drilling pattern consists of
alternating primary and secondary strokes. In each
sector, all the primary columns are performed before
the secondary columns.

The DSM machine tracks into position,  and the
horizontal and vertical alignments are checked. The
elevation measurements are made by using a small
tracking wheel attached to a digital tachometer. This
fixture is mounted at the top of the auger head and
tracks  the depth of the drill head.  The tachometer
output is  shown on a digital  display.  Machine
location verification is by use of a stationary laser.
The control of the positioning is to about one-tenth of
a degree from vertical for the suspended auger.
For large-scale commercial operations, a 4-auger
DSM  machine would be  used.  The overlapping
column arrangement still exists except that the
alternative primary and secondary columns are by
groups of four.

Comparison  to  Existing  Treatment
Technologies

Comparing  the  IWT   process  for  in  situ
stabilization/solidification to other cement-based
technologies reveals that unique characteristics
exist  in the IWT immobilization action of the
additive on  the contaminants and the equipment
used.  The proprietary additive is a silicate-based
cementitious  material, which also includes
organophilic clays. These types of clays have  been
known, with proper treatment, to adsorb organic as
well as inorganic material and  allow  interaction
with cement. They also can be tailored by chemical
treatment during additive preparation  to allow
adsorption of different groups of organic compounds.
Using these characteristics for  hazardous waste
immobilization is a  new and  novel approach. The
IWT chemical fixation products can be used for the
treatment of both organic and inorganic toxic wastes.

In situ treatment of contaminated  soils is  also
unusual. This approach uses  technology  that has
been used in Japan for two decades to improve soil
characteristics. It has been used in Japan, and for the
last few years by Geo-Con, Inc., in the U.S. for
shoring building foundations,  making slurry-
retaining walls, filling voids  in soil, and for
providing soil consolidation and environmental
                                               34

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Figure A-2.   Overlapping column arrangement.
barriers. Virtually all competing technologies first
excavate the soil, treat it, and then return it to the
ground. Thus, the major expense of excavating,
sizing, and handling the soil is eliminated with use of
the IWT/Geo-Con process.
                                                 35

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                                   Appendix B
                     Vendor's Claims for the Technology
The information in the appendix is prepared by
IWT and GEO-CON, INC. and provides their
claims for their technologies. The reader is
cautioned that these claims are those made by
the vendors  and  are not  necessarily
substantiated by test data. The claims are
evaluated against the test data in Section 3 and
Appendix C.
                                        37

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                                            Contents
Topic                                                                                 Page
Conceptual Basis of the Advanced Chemical Fixation Technology  .	   39
Chemistry Overview	   39
Overview of the In Situ Application   	:	   42
PCB Leaching and Extraction Studies  	   42
Treatment of ACF by High Content Organic Waste		   43
Aniline Fixation Study	   45
Treatment of Volatile Organics in a Soil Material with PFRS Materials  	   45
Treatability Studies of Metals and Inorganics  	   46
Summation  	   46

Table B-1  Infrared Data  	   51
Table B-2  DSC Data  	   51
Figure B-1 Coordination Complexes   	   40
Figure B-2 Pn to dn Bonding  	   40
Figure B-3 Lewis Acid Base Reactions: Formation of Sigma Bonds   	   41
Figure B-4 Observed Bonding Phenomenon in the HWT-23 Treatment Matrix  	   42
Figure B-5 Formation of Permanent Sigma and Pi Bonding (Covalent Bonding)  	   43
Figure B-6 Supramolecular Chemistry/Multiple and Secondary Bonding  	   44

IWT Response to the USEPA Applications Analysis  Report  	   46

Geo-Con,  Inc. Claims	   49
                                                38

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Conceptual  Basis  of  the  Advanced
Chemical fixation (ACF) Technology
Waste treatment techniques that are composed of
Portland cement, fly-ash, cement kiln dust, quick-
lime, soil,  clay, asphalt, sodium silicate, slag,
gypsum, etc.,  in various combinations  for
solidification/stabilization (S/S) have been used for a
number of years all over the world. Users and
suppliers of these technologies  have in some cases
also  used the term chemical fixation (CF) to define
various  compositions of these  materials, possibly
with the addition of trace compounds to accentuate
their effectiveness with certain  waste  types.
Whatever  the terminology  used, S/S  or CF,
particular compositions of these materials are  the
basis of the proprietary treatment products on  the
market. Certainly one of the major appeals of this
class of treatment technology is the relatively lower
cost, if the treatment is sufficiently effective for the
waste types to which  it is  applied. Stabilization/
solidification has been viewed by many  in  the
environmental  field  as  a  physical  or civil
engineering  process  instead  of a sophisticated
chemical system. Tests  for the effectiveness of
treatment revolved around certain level of physical
changes in the "ante  et post"  treatment state.
"Successful" treatments of some metals, radioactive
and  nonradioactive, in certain concentrations in
sludges, soils, and liquids, as measured by particular
light acid  and  water leach  tests, have given
additional marketing credence to the notion that this
is a viable and effective treatment for a wide range of
waste types. Very little  in-depth research of the
chemistry and physics of S/S and CF  was done
because "it worked", as determined by certain static
and  dynamic, deionized water leach tests. Also the
use  of  the term CF with various associated
unsubstantiated or stretched logic claims as to a
given product or composition's ability to treat a given
waste effectively added another  level of apparent
creditability.  In parallel to  the use of S/S over the
past few years, there has been a somewhat erratic, or
wandering, but yet evolving regulatory  structure,
influenced by an increasingly negative and dubious
public opinion of the true effectiveness of S/S and CF
and  its users. The environmentally active and
concerned public elements and  to an  increasing
degree  the  regulatory authorities  saw no true
distinction between S/S and CF except marketing
hyperbole. In many groups, S/S and CF are viewed as
"low tech, no-tech, or  pseudo-tech"  approaches to
waste treatment. Important to  solving  the
effectiveness issue are the questions of what
comprises reasonable,  realistic,  or necessary test
procedure of S/S  and CF technologies and the "how
clean is clean?" standards. The treatment evaluation
methods and standards for S/S and CF are a point of
contention among the users and marketers of S/S and
CF, competing forms of treatment, the regulatory
authorities, and the public.

In the midst of this complex scenario we have been
doing research into the basic chemistry of chemical
fixation  of organics  and inorganic  toxic
contaminated soils, sludges, and liquids for the past
few years. We believe the necessary reality of S/S, or
more appropriately defined CF, involves exceedingly
complex chemical mechanisms and phenomena, and
this class of technology should be evaluated on such
terms as to its true effectiveness. One  of the major
objectives of this article is  to develop a definitional
separation between the nature of S/S and CF using
the HWT-20 Series (Patent  Pending,  IWT)
compositions as the prototype of a new Advanced
Chemical  Fixation  (ACF) class of treatment
technology. In that regard, we will review GC/MS
readings of acid leach and solvent extraction tests of
cases involving soils  contaminated with PCBs and
other high content mixtures of organics treated with
the International Waste Technologies (IWT), HWT-
20 Series Products. A recently discovered problem
with high content organic waste treated with a
typical S/S mixture using a quick-lime, pozzolan base
will be  discussed. We have also used  infrared
adsorption (FTIR)  and  differential scanning
calorimetry (DSC) to give insights into the chemical
bonding mechanisms  of this particular  type of ACF
technology  with a range of organic compounds in a
pure liquid or contaminated  soil form. It would be
useful at this point to  give some  background
information relative  to the  chemical design and
analytical thinking that went into the HWT-20 ACF
prototype. As was implied earlier, we  believe  that
S/S and CF  should be based on an accurate paradigm
of the   chemical   process  rather than  an
adsorption/dilution panacea judged effective only by
end-state physical characteristics of questionable
relevance and validity. Our position is  that the
extent and strength of the chemical  bonding and
alteration to innocuous forms within the treated
matrix is a truer measure on the short and long term
effectiveness of this category or form of treatment.

Chemistry Overview

This HWT ACF technology is based on three sets of
interrelated functional chemical groups. There is a
matrix cement chemistry, a free radical and ion
attack and organophilic linking mechanisms. The
underlying concepts have  been discussed in some
intermediate level of detail in previous papers, so we
will summarize this time.

Cement Matrix Chemistry

The  objective of the cement chemistry  is not
primarily end-state  physical properties, but the
                                               39

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facilitation of the overall objective of bonding the
toxic  molecules  and  ions  within  a given
contaminated material. In line with that point,
certain aspects of the cement hydration reaction
(CHR) are altered and stretched out in  time; the
fibrils (sulpho-ferri-hydrates) that exist in the second
stage of the CHR are modified to be more chemically
reactive  and caused  to be more dense. Certain
admixtures are used to cause a greater dispersion of
the cement particles in impure environments which
in turn will promote better development of the weak
IPN (Interpenetrating Polymer Network) bonding
function. This function is the slowest reaction of all
three functional groups and its primary function is to
be the silicate anchor matrix to which all other
reaction products attach.

Free Radical and Ion  Attack Chemistry

This is a parallel chemistry that can be made up of a
wide range  of compounds  that produce highly
reactive ions and complexes in the HWT-20 slurry.
This activity does not  interfere with the functioning
of the other major functional  CF  groups.  This
chemical function should attack  various  toxic
organic  and inorganic  elements within  the
contaminated medium and reduce them to relatively
inert  forms or reaction products  that can
subsequently react with one of the other functional
groups in fhe HWT-20 ACF material. A simple
example  of this capability is the use of transition
metal complexes, but even these must be thought out
carefully for one could cause  certain counter-
productive reactions. An example of this in Figure B-
1, Coordination Complexes, and  an  explanation of
the bonding is given in Figure B-2.
    6 (CeHsOH; * M3*(Transition Metal)—«• [M (C6H5OH)6]3+
                    C6H5OH
                      O
                        xs     Octahedral Phenol
                        \  X    Metal Complex
  CeHsOH C£=
    s  a^    »    Nv

x^"   v^h^-N
^	^—W*"5;	     ^> °6H!
   X^ «^  •    v *      ^y
     ^^ •    ^. *    _^ .'
;OH
X
N
N
N
S


1
\~"
\
\
N\
.V
"" "w
/ X
£''
O
C6HSOH
    Evidence:
    UV - Visible Spectral - Drastic Color Change

Figure B-1.   Coordination complexes.
                           • nElectron Charge Clouds
                        Metal da orbitals (empty or
                        partially filled orbitals)
  Evidence:
  Shift in FTIR Frequency for Ring Breathing

Figure B-2.   Pn to dn bonding.

Organophilic Linking Mechanisms-
These are intercalation compounds, such as modified
smectite clays, that interact with  the organics
present,  within certain ranges  of predetermined
selectivity, by a sorptive process in  either of two
general modes. The strong, short-range  bonding is
based on a Bronsted and/or Lewis  acid or base
reaction (see Figure B-3), relative to such a reaction
we have observed with triethanolamine.  The weak,
long ranges forces are basically hydrogen bonds (see
Figure B-4), induced dipole or Van der Waals1 forces.
There can be an initial reaction based on the weak
force reaction and later a second strong or Lewis base
reaction.

These modified smectite clays have both organic and
inorganic properties due to the substitution of the
quaternary  ammonium  ions  in the  normally
inorganic clay structure of the Group IA and IIA for
metal ions. This makes them ideal linking
mechanisms between the toxic organics in the waste
and  the  cement matrix. The introduction of the
quaternary ammonium ions also opens the basal
spaces in a pillaring effect to allow like polarity
organics  into the strong force reaction zone. Bonds
can range from weak Van der Waals1 forces to strong
coordinate covalent bonds.

The  important point is that this is  primarily a
problem in supramolecular chemistry and the
multiple  and secondary bonding  and  positioning of
the appropriate  molecular structures is the key
issue. The individual  FTIR shifts on functional
                                                40

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                                              Aluminum Oxide Layer
FTIR Analysis
Triethanolamine
2104
1075
Treated
2297
1070
Shift
193
-5
Peak
Assignment
Amine Salt
Formation
H Bonding
                                              Silicon Dioxide Layer
                          X = Electron Deficient Species or H Which is a Lewis Acid.
                          Evidence: Shift in N - R (n) Frequency in Positive Direction (Increase)
                                        DSC Analysis - Triethanolamine
Edotherms
150.97
337.30
Hot
Vaporization
(Literature)
Kcal/mol
12.78
Observed H of
Vaporization
Kcal/mol
24.16
Percentage
Increase in
Energy
89.0
Boiling
Point
335.4
                                                                            Highest
                                                                          Endothermic
                                                                          Temperature
                                                                            337.30
Figure B-3.   Lewis Acid Base Reactions: Formation of Sigma Bonds (o).
groups seen are usually not considered large and in
some cases are slight, but the number of bonds, the
sum of the shifts, and the positioning of the bonds is a
stronger effect in most cases than one would see in a
primary bond. An indication of the strength of this
multiple and  secondary bonding phenomena can be
seen in "Percentage Increase in Energy" of the DSC
analysis of a given waste (see Figure B-3). We have
also done DSC studies on the treatment of pure
phenol, nitrobenzene, and trichloroethylene and
have achieved percentage energy increases of 220.7,
275.9, and 52.8 respectively. A significant adjunct
condition is that the behavior of a pure substance in
a laboratory gives one an idea of what is possible, but
in a real, complex waste  many other factors will
interfere  with the ACF material  chemistry in
achieving the maximum desired  effect. There are
some positive assisting factors but in most  cases one
must design ACF materials to overcome a variety of
chemical hurdles before the fixation reaction can
reach the desired level of efficiency.  The use of
advanced chemical techniques and analysis provides
invaluable insights into  the  waste chemical
mechanisms.

Fourier Transform Infrared (FTIR)--
FTIR studies are used to understand the extent of
interaction between the  toxic compounds and the
HWT-20 ACF  material.  This  analytic technique
measures the changes in vibrational  motion in
specific bond relationships. It also helps to determine
the functional elements present in a given molecule
involved in a bonding process.

Differential scanning calorimetry (DSC)—
DSC measures the  changes in temperature  and
energies associated with  various significant
chemical changes involved in bonding, such as the
enthalpies of melting, evaporation, decomposition,
                                                 41

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        Hydrogen Bonding of Phenol Molecules
                Oxygen
                   f
                                     • Aluminum
                                      Oxide Layer
                              Phenol Molecules
                                  Silicon Dioxide
                                  Layer
           Oxygen
           Evidence:
           Lowering of FTIR Stretching Frequency

    Phenol   Treated Phenol    Shift   Peak Assignment
   962 cm"'    934 cm"'    -28 cm''       C - O
  3640 cm"'   3632 cm"'     -8 cm"'   H - Bonded OH
 Figure B-4.  Observed bonding phenomenon in the HWT-
           23 treatment matrix.
phase transition, etc. This technique can indicate the
strength of bonding.

Overview of the In Situ Application
The application of the ACF technology can take place
above ground level using a variety of mixing systems
or in the ground, in situ, as was done at the former
General Electric transformer repair facility in
Miami, Florida. The use of high and/or low-pressure
rotary shaft injection, with or without mechanical
blade mixing,  has been done for more  than  ten to
fifteen years in the construction industry for creating
injection piles and sub-surface barriers.   It  was a
natural  extension of this construction method to be
used in  the treatment of contaminated soils and
sediments, if one had a cement chemistry that would
prevent both inorganics and organics from leaching
at an unacceptable  level. The low pressure rotary
shaft injection and blade mixing equipment offered
by Geo-Con, Inc. was chosen because it would give an
even, homogeneous blending of the HWT-20 ACF
with the soil and subsurface porous limestone strata
encountered at the site and create accurately placed,
consistently overlapping columns.  An additional
purpose of the in situ method, other  than the fact it
treats the contaminated soil in-place, is that GE was
interested in using this technique of application in
sites where there was volatile and semivolatile
organic contamination of the subsurface soils where
it would not be desirable to expose these soils to the
air by a removal technique.

At the SITE Program's Demonstration, Geo-Con
used a relatively small diameter drill — one yard —
for two reasons. The drilling for most of the time was
in rock and the objective was to prove the concept of
in situ treatment. The mixing drill process could be
operated in  sand/clay soils with a larger diameter
drill (2 to 3 yards) and/or multiple, parallel drills,
resulting in a  quicker and  more economical
treatment. In situ treatment costs can be as low as
$20 to 30/yard, excluding treatment chemicals, on a
large project, up to $60 to 70/yard in difficult
situations.

PCS Leaching and Extraction Studies
The HWT-20 CF Series was successfully used in the
treatment of PCBs at  the General Electric (GE)
Miami Site under the U.S. Environmental Protection
Agency's Superfund  Innovative Technology
Evaluation (SITE) Program. This application was
done in situ, using mixing drills down to 6.15 meters
(m) from Geo-Con, Inc. of Pittsburgh. The first 1.2 m
was sand, the second 2.5 m was a porous coral like
limestone, and below that quartz sand, with fresh
water at 1.2 m. The level of addition of the HWT-20
CF material was 15 wt% to soil. In other words, for
every metric ton of contaminated soil 150 kg of dry
HWT-20 was added in a slurry form: The maximum
concentration of PCBs was 5,700 ppm and was found
by GC/ECD. The leaching procedures  were the
USEPA  TCLP (Toxicity Characteristic  Leaching
Procedure),  18-hour dynamic acetic acid test, ANS
16.1 and the MCC-1P leach procedures. Essentially
no PCBs came out in the EPA testing, and only one
sample was found to leach in GE's testing, that was
1.2 ppb on a two-week old sample. GE did methylene
chloride extractions of drill core samples as well, and
did not find in excess of 206 ppm PCBs in the treated
samples using GC/ECD.

Some of the pre-project laboratory experiments,
carried out  by Dr. R. Soundararajan, gave some
insights into what was occurring in the treated soil
matrix. In a sample of PCB-contaminated soil from
the same site and the same sample barrel as the
above  sample,  eight-hour methylene chloride
extractions were performed on the untreated and
crushed treated samples.

Analysis was done by GC/MS with the machine
calibrated against all 221 position-isomers of PCBs.
In one sample of this experiment, an admixture was
included that produced a sulfurous acid that would
totally disable  the organophilic clay linking-
                                                42

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mechanisms between the PCBs and  the  slower-
developing silicate-based anchoring matrix. In the
second sample, the admixture was removed so that
primary linking mechanisms could function. The
results are as follows, untreated soil released 28,800
ppm PCBs in a methylene chloride extraction:
                      Sample 1:
                     Admixture
  Sample 2:
     No
 Admixture
  Treated extraction   26,437 ppm    2,800 ppm

  Treated TCLP       10,437 ppm     12.5 ppm
These  tests  were done only  three days  after
treatment. A treatment dilution factor of 20% is
included in the above numbers. The TCLP numbers
did improve with the age of treated  sample.  This
particular sample showed  only 5,000-6,000  ppm
values  using standard GC analysis, mainly because
the GC/MS was registered with all 221 PCB isomers.
Also high values (40,000-50,000 ppm) of chlorinated
benzenes were found, most likely the decomposition
products of the PCBs, since no chlorinated benzenes
were ever used at the site. The chlorinated benzenes
were reduced,  in a similar  proportion to the
reduction in PCBs of Sample 2, from untreated to
treated extraction values. Almost all of the existing
PCB isomers after treatment were the low value
chlorine forms.

The conclusions of the above experiment were
supported  further in  another set of leach and
extraction tests performed on a sample of a clay/sand
soil contaminated with low levels of PCBs (290 ppm).
The eight-hour testing  procedure was the same  as
above,  with the focus on which isomers were bonded
or retained in the  treatment matrix  after solvent
extraction of crushed treated samples.  The TCLP
leach tests  of the treated material were all  non-
detectable. The  sample cured for seven days. The
treatment level of HWT-20 was 15 wt% to the weight
of soil. In the untreated  soil there  was  some
chlorobenzenes and substituted phenols but none
were found in the treated soil. Only the lighter PCB
isomers (tri, tetra, and penta) were  found in the
treated soil. The hexa- and hepta-chlorophenols were
not found in the treated. The  total PCB content
extracted was 190 ppm or 65 wt%.

Relative to PCBs, the current HWT ACF treatment
technology is able to alter or bond to a high degree
the heavier chlorinated  PCB molecules and to a
lesser degree the lighter chlorinated  molecules. It is
very effective in preventing the leaching of PCBs
against the TCLP of all types. Also the HWT-20 ACF
treatment sufficiently bonds  and prevents  the
leaching  of the PCB decomposition  products,
substituted.benzene and phenol  compounds. Newer
formulations of a more advanced IWT ACF product
show significantly greater  rates  of bonding or
chemical alteration of organics, including PCBs. An
example of the treatment of a PCB-containing waste
with our newer "Polyfunctional  Reactive Silicates"
(PFRS) (TM) is shown in Figures B-5 and B-6. These
ACF materials are based on new  inorganic carceplex
structures and heretofore non-existent  organic
trailers. As the results show, this is the most
effective PCB reaction to date and the  research is
continuing to be positive. The  first of these new
PFRS materials should be commercially available
later this year.
                   A  = O  +  H2X

                   ACF       Toxic
                    Material   Waste
                         i-     A = X  +  H2O

                          Irreversibly Bonded
                          End Product
                 Figure B-5.  Formation  of  Permanent o +  n  Bonding
                           (Covalent Bonding),
                 Treatment by ACF of High Content
                 Organic Waste
                 An organic content waste with a high percentage of
                 heavy hydrocarbons and with relative trace to small
                 fractional loadings of volatile and semivolatile toxic
                 compounds is normally a difficult material for the
                 usual S/S mixtures to effectively treat, unless some
                 integer multiple by weight of the S/S material is
                 added to the weight of the waste and  end-state
                 physical properties are  all that is being considered.
                 The waste sample, in this case, was  a soil with  a
                 heavy concentration of long chain hydrocarbons from
       Bis( l-chloro-iso-propyl)ether

       Naphthalene

       Phenanthrene

       Benzo(A)anthracene
Untreated extraction

      8,528 ppm

     18,060 ppm

     20,184 ppm

     30,460 ppm
       Treated extraction       TCLP

              ND                ND

            1,445 ppm             ND

              ND                ND

              ND                ND
                                               43

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                                     Dichlorobiphenyl
                                       AI2Oy Layer
            O
O
            \
          S,O2 Layer
                                     O          O
                                      Solvent Extraction and Leach Results:
Untreated
(ppm)
PCB 17,580
Dichlorobiphenyl
1150cm'1
Solvent Extraction of Treated (ppm) TCLP
N.D. N.D.
FTIR Study of PCB
Treated PCB Shift
1118cm'1 -32
Peak Assignment
Cl to Al
                                                           Coordinate Bond
       Figure B-6.  Supramolecular chemistry/multiple and secondary bonding.
an acid/clay process for recycling used oil. The major
organic toxic components of  this waste, as
determined by a solvent extraction and analyzed by a
GC/MS are shown below:

This contaminated sample was  treated 50% by
weight with an experimental and more  advanced
chemical fixation material and allowed to cure for
only two days. This treatment level is too high for an
actual project, but what we were trying to  achieve is
an accelerated effect that would allow us to examine
the bonding activity more quickly  by the solvent
extraction (GC/MS), FTIR,  and DSC analyses. A
dilution factor of 50% was used in all quantification.
Standard methods of analysis and QA/QC were used.

With such a complex mixture to analyze by FTIR and
DSC the approach had to be different than working
with a pure, known organic liquid. In using FTIR, we
focused on functional groups that  we knew were
there in relatively large concentrations and looked
for shifts within those groups to indicate a level of
bonding activity. In reviewing the data, we have
found that there were significant shifts in a number
of FTIR frequency regions, and hydrogen bonding
was  occurring  between  the aliphatic amines,
hydroxyl compounds, and  the oxygen in the  A^Os
and SiC-2 in the CF material. There was an  amine
salt formation, as the result of a Lewis base reaction
at 1,580 cm-1. The most significant shift occurred at
1005 cm-1 where a hydrogen bond was formed with
an SiC-2. This is explained by the fact that the oxygen
in the silica strongly interacted with the hydrogens
of alkyl, hydroxyl, and amino groups, which results
in a reduction of the O-Si-O bond order (Table B-l,
Infrared Data).

The DSC data (TableB-2,  DSC Data) also confirms
that relatively significant  bonding activity  is
occurring.  The enthalpy of vaporization  has
increased by 54.9% from untreated to treated soil.
                                                44

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The DSC analysis is an energy summation function
rather than a focus on a specific reaction.
Aniline Fixation Study
Aniline is considered to be a difficult compound for
chemical fixation to control in terms of leaching and
is also extremely toxic. IWT ACF products were
tested against fourteen other products and mix
designs in this treatability study. The objective was
to treat the aniline contaminated lime/soil (pH 12.5)
material such that the TCLP value was less than 50
ppb. IWT tested successfully using the HWT-9 ACF
material and will be used in the remediation project
starting in November of 1989 by Geo-Con in an in
situ mode.

Cement leach values continued to increase over time.
FTIR studies were done on the aniline plus cement
and aniline treated by HWT-9 samples. These results
supported the premise  that there  is significant
chemical bonding by a different and shifted chemical
activity spectra of the HWT-9, particularly in the
characteristic absorption bands associated with the
aniline  molecule as  compared to the cement plus
aniline.

Treatment of Volatile Organics in a Soil
Material with PFRS Materials
In a recent analysis by Kiber Associates, Atlanta, for
a major corporation one of IWT's new Polyfunctional
Reactive Silicates designs was bench tested in a
treatment of  spiked soil samples from  Miami,
Florida, with seven VOCs. The mixing of the samples
for the TCLP tests took place  in a  controlled
atmosphere and checked for the  degree  of
volatilization of the VOCs during mixing and curing.
Temperature profiles of the samples before and after
treatment were also plotted.

Samples were spiked with the following compounds
and concentrations: benzene 75 ppm, chlorobenzene
150 ppm, m-xylene 10 ppm, 1,1 dichloroethane 10
ppm, 1,3  dichloropropylene  10 ppm,  carbon
tetrachloride 10 ppm, and ethyl benzene 10 ppm.

All samples were treated at 15% by weight of the
treatment material, with a 30 day cure.

Methonol Extraction of Treated Material - Detectable
   Extraction Data (ppb)
HWT-20 - 27 benzene, 1072 chlorobenzene, 47 ethyl
   benzene, 177 xylene
HWT-20M - 591 chlorobenzene
HWT-23H - 444 benzene, 6407 chlorobenzene, 370
   ethyl benzene, 262 xylene
PFRS - 320 chlorobenzene
The  PFRS material could be altered further to
improve the solvent extraction results of  the
chlorobenzene.

TCLP Leach Data of Treated Material - Detectable
  Leach Data (ppb)
HWT-20 -14 benzene, 404 chlorobenzene, 73 xylene
HWT-20M-306 chlorobenzene
HWT-23H - 364 chlorobenzene
PFRS - 45 chlorobenzene

The temperature of the samples HWT-20 and HWT-
23H  rose  from 17°C to 25°C during mixing and
curing, HWT-20M went to 29°C, and PFRS went to
32°C. Total VOCs lost into the air during mixing and
curing was 3% for the cooler treated samples and
4.5% for the PFRS and HWT-20M samples. This air
leaching should be reduced significantly if  the
application was done in-place, underground, instead
of in the open in an above ground mixer.

Independent analytical  work  done  in  The
Netherlands on PFRS treated soils contaminated
with mercury, arsenic, chlorobenzenes, organo-
chloro-pesticides, chloro-phenoxy-pesticides, organo-
phosphate pesticides, nitrophenols, chlorophenols,
and carbon disulfide against the Dutch availability
and leach tests  was successful. Testing  of these
samples in the U.S. by TCLP and solvent extraction
procedures was also well inside the EPA limits.

Recent experimental  work  done by  Dr. R.
Soundararajan has indicated that lime, lime/fly ash,
or pozzolan-based S/S of organic-content waste of a
sufficient level (this threshold is not yet known, but
certainly the oil recycling waste in this case applies)
will generate significant  carbon monoxide and/or
acetylene gas when exposed to water of even mild
acidity. Also, during the process  of S/S or  CF
treatment, it is desirable to keep the heat generation
by the reaction with water as low as possible, since
the more heat generated the more the volatilization
of the  organics. The  IWT ACF technology only
contains trace amounts of lime in the cement fraction
of its composition and no pozzolans are used. The rate
of addition of the IWT ACF materials  used to weigh
waste is relatively low, 12% to 20%, and has a lower
heat of hydration than straight cement.

Other "tricks" one must watch out for in the field of
S/S or chemical fixation are the use of compounds
that  convert various toxic compounds  to other
compounds that can be volatilized out of the system
during  the  cement or poz/olan/lime hydration
reaction, and/or a masking technique by using
certain long chain hydrocarbons such as mineral oil.
The way to screen for these is: 1) know the addition
rate of the treatment material relative to the weight
of the waste; 2) determine whether organic based
additives  being used; 3)  use  a GC/MS as  the
                                               45

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Total aniline (ppm)
146 (10 day cure)
325 (10 day cure)
325 (10 day cure)
325 (30 day cure)
Cement (32 days)
Percent treatment
by weight
20
20
30
20
30
Untreated TCLP
(ppm)
7.1
12.5
12.5
12.5
12.5
Treated TCLP
(ppb)
ND<1
110
ND<1
ND<1
100
analytical instrument with subtraction filtering; 4)
do a complete priority pollutant scan for volatiles
and semivolatiles in the treated analysis; 5) consider
an air-leaching test during the mixing and hydration
phase of the pre-project bench testing and during at
least 30 days after if you suspect this approach is
being used.

Treatability Studies of Metals and
Inorganics
 I.   Arsenic and Mercury in Soil

     Total concentrations - As  43,000 ppm, Hg
     5,300ppm

TCLP values after seven days of sample treated at
30% by weight with HWT-11 was the following, As
3.5 ppm and Hg 0.06 ppm. These numbers should go
lower as the sample cures further.

II.   Chromium + 6 and Cyanide

From another site in Alabama the  following was
obtained from a treatment with HWT-11H compared
to treatment by straight Portland  cement.  Total
chromium 6,310 ppm, total cyanide 235 ppm.

Untreated leachate, Cr 37 ppm, CN 0.34 ppm
                             HWT-11H Treatment
                             Cr       CN

                             0.29 ppm <0.02 ppm

                               BD     BD
  Treatment
  to/weight of  Cement Treatment
     soil     Cr      CN

     15%     5.25 ppm  0.86 ppm

     35%     3.93 ppm
     BD - below detection

III.   Hexavalent Chromium
Waste lagoons contaminated  with chromium  at
7,155 ppm. Cr+6 leached at 150 ppm. Treatment
was at 25% by HWT-11H. The leach data from a one
day  cure was Cr + 6  nondetectable and  total
chromium leached at 0.15 ppm.

IV.  Arsenic, Lead, Copper
A soil sample was contaminated with arsenic 2,200
ppm, lead 670 ppm, chromium 1,250 ppm, and copper
at 3,000 ppm. Treated at 15% by weight with HWT-
11 the EP Toxicity leach values after a one week cure
were  arsenic  0.126 ppm, lead  nondetectable,
chromium 1.1 ppm, and copper 0.22 ppm.

Summation
Chemical fixation technology is far more advanced
and cost effective than most people realize, especially
from those companies or groups that have done in-
depth chemical research of the basic fixation reaction
mechanism.  International Waste Technologies has
and is doing this basic research and believes that the
HWT ACF  Product Series and  the  new,  more
advanced products (PFRS) that will come out in the
near future will compete favorably with thermal and
biological  methods in the destruction, alteration,
and/or bonding of organics and the immobilization of
inorganics. The effectiveness of ACF technology can
be verified analytically, with relative quickness and
function  in a  wide  range  of contaminated
environments at relatively acceptable costs and ease
of use factors. An important key to the success of this
category of toxic waste treatment is for the
regulators and users of this type of technology  to
insist on high standards of relevant chemical testing
and verification  in  the  pre-project  treatability
analysis  and careful  QA/QC during project
application.

In situ applications  that are effective  in terms  of
homogeneity of mixing the ACF material with the
contaminated soil to the required level and that do
not  leave any voids can be an effective, economical,
and a necessary part of the waste treatment picture.
The Geo-Con system successfully demonstrated that
objective.

IWT Response to the USEPA Applications
Analysis Report
The EPA has taken a generally critical  approach,
particularly with respect to the fixation chemistry,
in this applications analysis. Based on the drafts we
have received to date, the overall reasoning  of this
position is in  general  rather  curious to us, but
                                               46

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specifically the EPA has been negative  in the
following nine major points.

1. The EPA has ignored the use of the appropriate
  types of chemical analysis that would be  able to
  discern  whether the  IWT chemical fixation
  material, HWT-20, is in fact chemically bonding
  with the PCBs to any  degree instead  of a weak
  adsorption, encapsulation, dilution phenomena as
  its total means of waste treatment. The chemical
  bonding could have been verified by using FTIR
  and DSC analysis of the PCB-contaminated site
  material treated with the HWT-20 in a bench top
  test. The chemical bonding capability to organics
  of the IWT fixation material is central to IWT's
  product claims. IWT did perform such analysis on
  contaminated soil from the site but was unable to
  convince the EPA to duplicate these tests  (see
  section titled "Vendor  Claims",  subtitled "PCB
  Leaching and Extraction Studies"). Their position
  is that IWT agreed to a test plan in March 1988,
  which we did. They then  took the position that
  there were no conditions under which the test plan
  could be amended. The main reason we asked for
  additional testing to clear up the bonding question
  was in order to counter the  EPA's speculative
  attack to discount our product claims  in the
  various draft reports it sent to us. The additional
  testing requested by  IWT would have  been a
  relatively small additional cost and certainly it
  would  be warranted in the case  of  a new
  technological approach  along with all the
  conventional testing. The analytical procedures
  needed to be expanded over what had been done in
  the past to verify our proposed concept. Instead the
  EPA speculated and implied from a generally
  uninformed position that, at best,  there  was no
  evidence to support this claim. In fact, there is no
  way to judge  what relevant chemical processes are
  occurring and  how effective  they are from the
  analytical work done by the EPA. The claim of
  chemical bonding with organics  is  important
  because it lifts the  solidification/ stabilization
  (S/S) process to a new and important level over
  what has been done in  the past in this field. S/S is
  relatively inexpensive  and easy to use. It is also
  easy to  verify its effectiveness compared with
  other forms of waste treatment and if it can reach
  a new and  important plateau of quality of
  treatment, then it is very significant.

2. The EPA used a technology evaluation team of the
  IWT SITE Demonstration which had a perspective
  anchored in a concept structure that reflected the
  antiquated  and simplistic notions of chemical
  fixation as a physical process  that  should be
  evaluated like an extension of civil engineering
  testing.  IWT is not taking the position that all
  physical testing  is  wrong, only  that  this
  evaluation process  should have  been  augmented
  with some innovative expertise in the area of
  inorganic/organic chemistry, clay chemistry, and
  physics. This would  have caused  the  EPA to
  expand the initially agreed to test plan.

3. The EPA has mentioned many times in this report
  that the HWT-20 fixation material freeze/thaw
  results were poor. This may be true from the point
  of view as a building  material, but the EPA had
  failed  to  do  any leach testing of  the  treated
  material that went  through the  freeze/thaw
  testing to see if the freeze/thaw process affected in
  a  negative fashion  the  HWT-20's ability to
  prevent  leaching to an excessive degree.
  Continued freezing and thawing will break the
  sample into small pieces. The TCLP leach  test
  requires the sample to be ground to a small grain
  size and  the HWT-20 did  well  on the TCLP
  testing. TCLP tests on the samples used in the
  freeze/thaw  tests would  have been simple to
  perform. Also, the chemical fixation material is
  designed on the basis  of many factors. If freezing
  and thawing were proven an important issue, the
  mix  could  be  changed  to  improve  its
  characteristics in that respect. This change is
  simple cement chemistry. Freezing  and  thawing
  are not going to occur from the surface to twenty
  feet down in Miami,  Florida. Also most of the
  treatment occurred under water, therefore the
  curing treated mass would acquire  a lot of pore
  water  which, when exposed to freeze/thaw cycles,
  will cause cracking. In the  wet/dry weathering
  test, which is really  what  will happen in  this
  environment, results were excellent. Permeability
  results were in  the  range of what would be
  acceptable as a liner material.

4. The dilution factor issue of the mixing process of
  Geo-Con's in situ mixing drill  could have  been
  determined absolutely in properly controlled, pre-
  project bench testing rather than having  the EPA
  speculate about this effect. The EPA postulates
  that since there is 95% reduction in the presence
  of metals from untreated  to treated B-6 and B-7
  samples attributed to mixing, then that should
  correlate  as a one to one mapping to the reduction
  of the  presence of organics. What valid reasoning
  states  that the metals and organics must always
  congregate  in the same area? The majority of
  outstanding questions relating to the effectiveness
  of the  HWT-20 material revolve around the fact
  that insufficient  pre-project bench testing was
  done and once the test plan was established many
  months prior to the actual demonstration  it
  seemed set in concrete. Many of the important
  questions could have been resolved even  after the
  demonstration by doing chemical bench studies
  then, but that seemed impossible. It is not IWT's
  fault that this was not done. We raised the issue
  time  and  time  again  in various  written
                                                47

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   communications to the EPA project management.
   The report penalizes us and our technology for
   these deficiencies. They advised IWT to apply for
   another study.

5. The EPA buries in the text of this report rather
   than explaining in the various  summaries that
   this is an actual project for General Electric (GE),
   not something contrived for an  EPA technology
   demonstration only, and that the requirements
   placed on IWT and GE by the involved State and
   Federal  regulatory authorities relative  to the
   efficacy of the chemical fixation treatment are tied
   to PCBs only, and that VOCs were not an issue in
   terms of treatment at that time. IWT could  have
   added additional compounds into the HWT-20
   mixture to improve its ability to reduce leaching
   of VOCs, but this was not required. Even with this
   handicap the HWT-20 material affected a drop in
   the leaching of the total VOCs by a factor of 147
   and 13 (see Samples B-6, B-7) and a factor of 36
   and 22 in the total content of VOCs. Even relative
   to the immobilization of metals this report seems
   to cast doubt on the capability of the HWT-20
   chemical fixation material. In  contradiction  to
   this implication, the EPA testing shows that the
   metals passed even drinking water values in the
   leach testing on the treated  materialv Further
   independent testing on the treatment'of VOCs
   was done on various mix designs of IWT chemical
   fixation materials by a major U.S. corporation and
   the  results are given in the  section titled,
   "Treatment of Volatile Organics in a Soil Material
   with PFRS". This clearly shows the significant
   impact of formula  changes  on the  ability to
   contain and chemically fix VOCs.

6. The EPA refers to test information, reports, and
   articles given to them by IWT as evidence to
   support the basically negative  premise of this
   applications analysis.  These reports and articles
   were put together over a four-year period under
   different requirements while the IWT chemical
   fixation technology was in the process of
   evolution, and it still is changing as we learn
   more. There were not even specific leach value
   standards set at the time that some of this work
   was done. The test work reported was always run
   by independent, credible  laboratories working
   under the prescribed EPA and analytical
   procedures at the time. This was not a coherent
   body of  work  strictly put together for  this
   Applications Analysis  Report, it  was information
   given to the EPA for educational purposes on the
   development of the thinking and  experimentation
   as the technology evolved. It was meant to  give
   them the fundamental issues involved, not be used
   as evidence against IWT.
7. The EPA explanation of the nature and value of
  FTIR and DSC analysis is completely lacking and
  raises the  question about  their capability and
  reasoning behind their position in writing this
  report. Their  understanding  of bonding  is
  insufficient  as well  and.shows  in  their
  explanations in the draft reports we have seen to
  date.

8. The comments the EPA makes on IWT's lack of
  field experience  seem to us unfair  since the
  regulations and  interpretation  of  these
  regulations which  make the  IWT technology
  viable commercially have only been in effect since
  late 1987 and the body of regulation that governs
  what and how waste can be treated by chemical
  fixation, especially organics  to pass TCLP, is still
  evolving. Even considering this, IWT has gained
  the confidence  of companies such as General
  Electric and Westinghouse. Both Geo-Con and
  Westinghouse Environmental are including the
  IWT advanced chemical fixation  technologies  in
  conjunction with  their  waste treatment
  marketing. IWT  has   subcontracted   to
  Westinghouse in completing a 10,000 yd3 project
  to treat lead-contaminated soils in Atlanta.
  General Electric will complete  the  8,750 yd3
  Miami Project (which will include the  treatment
  of PCBs, VOCs, and metals) starting in November
  1989 using the IWT treatment materials. Region
  IV-Atlanta of the  EPA selected,  based on
  independent testing, IWT to  supply the  treatment
  material for a  site  containing cyanide  and
  hexavalent chromium to  drinking  water
  standards. IWT was also selected and has supplied
  the Italian Government with fixation  materials
  for the first remediation project in Italy under the
  new regulations that are modeled after the U.S.
  environmental  laws,  including the use of the
  TCLP tests.

9. No matter what IWT claims  relative to the ability
  of its fixation products to treat a given waste, and
  even if we received an outstanding rating by the
  EPA in this report, every project situation would
  require this treatment technology to be  proven
  again and again in appropriate pre-project bench
  tests, technology reviews, and possibly  even pilot
  project tests. This technology has a wide range of
  applications, is  effective if  proper screening  is
  done, and is economical  and efficient.  The IWT
  chemical fixation technology and the in situ
  method of application must not be too bad if three
  of the EPA technology evaluators used in  this
  project decided to go into business copying at least
  the form, and to a yet unknown  degree, the
  content of the technology to become competitors of
  IWT and Geo-Con before this  report  was even
  finalized.
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  EPA HAS TURNED OVER THIS MATTER TO
  EPA'S OFFICE OF INSPECTOR GENERAL FOR
  INVESTIGATION.

Geo-Con, Inc. Claims
Geo-Con is generally in agreement with the SITE
Demonstration Report as regards comments relating
to Geo-Con's Deep Soil Mixing (DSM) System.

We do feel, however, that some clarification is
needed pertaining to the report's assertion that
"location of the soil columns deviated from the
planned points and some untreated areas between
columns exist".

In actuality, the locations of most columns  were
within normal drilling tolerances.  One  column
deviated six inches. A graphical  plot  was made of
actual locations of columns  and untreated areas
referred to were assumed from that graph, and not
found through the coring program. For the most part,
the columns created  are slightly larger than the
nominal thirty-six inch diameter which accounts for
minor deviations. In any case, the distance between
centers of columns can be shortened to raise the
factor of  safety against an  untreated area. In
general, the report confirms that the soil mixing was
very effective.

DSM has proven to be an excellent method of mixing
slurry with contaminated soils for chemical fixation.
A completed DSM fixation project  results in  a
homogeneous mixture of slurry and in situ soils. It
appears that  the  question  to  answer is what
materials would be effective in neutralizing specific
pollutants and in what dosages.

There are  other proven  uses  of  DSM  for
environmental applications that are also economical.
DSM has been used to construct hydraulic barriers to
isolate contaminated soils and prevent contaminated
groundwater from leaching into a nearby water
source.

DSM was selected over other conventional hydraulic
barrier techniques  because it does not require any
soil to be excavated, thereby eliminating costly
backfill and disposal. A cement-bentonite slurry
blended with soil  to  meet the permeability
requirements and reinforcing  steel was added for
structural requirements.

For solidification and stabilization of contaminated
soil by DSM,  many common material's such as
cement, lime, kiln dust, and fly ash can be batched
into slurry form and mixed into the soil.

For aerobic bacterial destruction or organic wastes,
oxygen can be pumped through the augers and out
the tip at  high enough pressures to aerate the soil
and accelerate its  bacterial  activity.  (Existing
applications of aerobic destruction are limited to
near surface spills.)

Steam or other heated gases can be injected through
the augers to strip the soil of  volatile organics. A
hood at the surface would evacuate the waste gases
to a plant for recover and disposal.  This method
would decrease the potential for offsite emission that
is always present during an "evacuate and remove"
type of operation.

Shallow Soil Mixing (SSM) is a variation of DSM.
SSM utilizes a single large  diameter  auger to
perform stabilization and fixation projects where the
contamination is less than thirty feet deep. It is more
economical than DSM at  shallow depths because
much more soil is targeted at one time.

DSM offers a  number of  advantages over
conventional techniques:

  •  No excavation is required.

  • Treatment at depths up to 150 feet.

  • Effective for a wide variety of soil  conditions.

  • A relatively rapid construction sequence.

  •  Easy to adjust mix designs and flows.

  • No need to dewater.

Geo-Con Background

Geo-Con, in addition to its soil improvement and
specialty foundation work, is a full service remedial
construction company. Geo-Con has experience in
drainage ditches,  capping,  lagoon/landfilling
closures, soil/sludge stabilization, and  drum
removal. Geo-Con is also a leader in  slurry cut-off
walls, having installed more than 400  walls to date,
including soil-bentonite, cement-bentonite, and soil-
attapulgite.

In addition to the  DSM  soil-fixation project in
Hialeah, Florida,  Geo-Con has performed  the
following selected projects:

Site Remediation Stabilization and Geomembrane
Installation Sludge Pond Closure/Vickery, Ohio-
The sludge pond closure project conducted in
Vickery, Ohio, by Geo-Con in 1986 was the  largest
privately financed project of its kind in the  nation.
Approximately 265,000 cubic yards of PCB and
dioxin-contaminated metal sludges were stabilized.

Geo-Con first completed a pilot project  to
demonstrate the technical feasibility of handling and
                                               49

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solidifying the waste with cementitious  agents.
Eventually,  all the sludges  on the sites were
stabilized, without incident, in the  face of keen
public awareness and publicity. All solidified
sludges,  contaminated soil, and  debris were
stockpiled for temporary storage. All solidification
work required EPA Level B and Level C worker
protection, which was monitored pursuant to a site-
specific  health-and-safety  plan by  in-house
industrial hygienists and site safety officer.

The empty and decontaminated sludge ponds were
regraded  to form one  large cell  to  permanently
contain  the stabilized sludge.  Geo-Con  was
contracted to construct the RCRA closure cell. The
cell will be comprised of a clay liner  with three
synthetic liners and leachate collection and detection
systems. At the  time of the writing of this  project
summary, the capillary barrier system and clay liner
had been  completed and the synthetic liners were
being replaced.

Geo-Con Remediation Experience

Sludge Stabilization and Capping Project - Sparta,
Wisconsin-
Geo-Con was selected to perform various services
leading to the closure of a metal plating lagoon and
dump  site  in Southern Wisconsin.  Geo-Con
performed sludge and waste stabilization laboratory
studies to determine the most cost-effective
acceptable reagents for this particular  waste stream.
Once the reagent  was identified,  Geo-Con  in
conjunction with EDER Associates,  the Owner's
environmental consultant, prepared health and
safety programs  and operating plans to support the
closure plan.

Geo-Con stabilized over 2,000 cubic yards of sludge
on this project and is performing grading operations
to allow placement of final cap and cover systems.
Site Remediation - Lagoon Solidification Cap and
Landfill Creosote Impoundment/Savannah,
Georgia-
Geo-Con closed an  unlined lagoon for a  wood
treatment facility in Savannah, Georgia. This project
involved  the onsite, in situ stabilization of 12,000
cubic yards of creosote contaminated sludge to attain
specified strengths and moisture  content.  After
solidification, the sludge was transferred to an onsite
disposal location where the waste was compacted,
graded, covered with a clay cap, synthetic liner, and
cover materials. All operations were accomplished by
Geo-Con  forces using EPA Level C  and Level D
protection equipment along with a "real time" air-
monitoring program.
Site Remediation - Deep Soil Mixing Cutoff Wall -
Bay City, Michigan—
This project utilized the DSM technique to prevent
PCBs from migrating into the  Saginaw  River. A
large manufacturing company required a cutoff wall
to contain groundwater contaminated by its
operations.

Because the soils were very soft (< 1 blow count per
foot), a conventional soil-bentonite cut-off wall could
not be constructed. The  problem  was  magnified,
because the alignment of the wall is as close as six
feet in some areas to the Saginaw River. If the soil-
bentonite trench were to collapse during
construction, and if there was a  break of adjacent
lagoons, there could have been a disastrous spill. The
Owner opted for the DSM technique, which produced
a 4,500-ft-long impermeable structural wall 35 to 65
ft deep, which was keyed into a subsurface aquiclude.
Treating the soil  in-place saved the Owner  the
expense of removal and disposal of the contaminated
soil  and eliminated a sensitive and complicated
operation.
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Table B-1.    Infrared Data
    Waste extract
        cm-1
    Waste
extract + binder
     cm-1
Infrared frequency
      shift
      cm-1
                                                                   Infrared function group assignments
        3,394
        3,382
        3,373
        1,597
        1,035
     3,385
     3,372
     3,355
     1,580
     1,005
       -9
      -10
      -18
      -17
      -30
  OH Stretch O--H....O
  NH Stretch N—H....O

  Keto Group C—O....H
Hydrogen Bonding Si    Si
                       O
     Table B-2.    DSC Data
                                    DSC Endothermic Peak Values
Temperature
(Degrees C)
Waste extract 1 38.90
Waste extract + binder 121.2
414.4
414.5

Waste extract
cal/gram
Total H (vaporization) , 18.63
Total H (vaporization)
corrected to 100%


TGA - Percent wt. loss at
given temperature range
PERCENT INCREASE in H
H. (Vaporization)
cal. per gram
18.63
6.15
2.32
2.06
10.53 Total
Waste extract + binder
cal/gram
10.53
28.65
Waste extract
+ binder

36.48
54.9
      (vaporation) for waste
      extract + binder
                                                51

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-------
                                         Appendix C
                           SITE Demonstration Test Results
Introduction
A very narrow scope of soil contaminants exists at
the GE electric service" shop. The untreated soils
measured in two sectors showed a maximum PCB
concentration of 950 mg/kg, which was less than one-
half the anticipated value based  on  sampling
performed by Law Environmental (LE) for GE. The
PCB concentrations appear to be very localized,
particularly in Sector B where  the higher PCB
concentrations were seen. The additive was mixed
with the  soil by the Geo-Con/DSM  equipment,
providing vertical,  and some horizontal, blending.
After soil treatment, which produced a mass increase
of 32% due to the addition of HWT-20 and water, the
maximum PCB concentration was 170 mg/kg,  with
only one other sample value above  100 mg/kg. In
Sector B, the average PCB concentration of the
treated soil (50 mg/kg) was about one-quarter of that
of the untreated soil (180 mg/kg) after correcting for
the additive volume. These low soil values produced
TCLP leachates  very close  to the detection limit,
which made  interpretation of the  results more
difficult.

Although high VOCs were measured — up to 1,485
mg/kg total ~ the VOCs were  found  in only 3
samples, which were in Sector  B. This  was
insufficient information from which to draw any firm
conclusions. Heavy  metals,  at relatively low
concentrations (a maximum of 5,000 mg/kg total),
were measured at only the same 3 locations as for the
VOCs. Thus, the significance of the results is limited,
both due to the small number of samples and low soil
and leachate concentrations. In addition, IWT claims
that their HWT-20 additive was not tailored for
immobilization of VOC and metals, only PCBs.

The analytical data consists of physical and chemical
tests on untreated and treated soils from various soil
depths between 1 and 17 ft  below grade. Clean soil
and contaminated soil blends from both Sectors B
and C were mixed in the laboratory with Type 1
Portland cements to provide a baseline comparison to
the soil treated with HWT-20. The demonstration
 results are discussed  separately in terms of the
 physical tests, chemical tests and operations.


 Results
 A large amount of analytical and operating data was
 obtained, but due to the limitations described above,
 the program objectives  could not be completely met.
 The detailed results and operating summaries are in
 the Technology Evaluation Report [4]. The results of
 the physical testing are shown in Tables C-l through
 C-5, at the end of this Appendix.


 Physical Results
 The physical tests showed that the IWT in situ
 stabilization/solidification process could readily
 solidify soils contaminated with PCBs and VOCs.
 However, the total organics content of the soil tested
 was very  low,  mostly under 1.0 wt%, with a
'maximum of 1.6 wt% at B-6, a location of high VOCs.
 The process produced a structurally firm material
 with good physical properties, except under the
 freeze/thaw weathering testing  where large weight
 losses,  more than 5%, were measured  on many
 samples. The moisture content  of the treated soil
 samples averaged about 18 wt%.

 On  treatment,  the  bulk  density  increased
 approximately 21%, from 1.55 g/mL (96.7 Ib/ft3) to
 1.87 g/mL (116.7 Ib/ft3). This was for an average
 weight addition of HWT-20 and  water of 32%. Thus,
 the volume increased by 8.5%, which is equivalent to
 about an 18-in. ground rise in Sector B and 14 in. in
 Sector C. This was confirmed by observation of the
 ground rise in the two sectors — a 1 l/2-to-2 ft rise in
 Sector B and a 1- to 1-1/2-ft rise in Sector C.

 The unconfined compressive strengths  (UCS) in
 Sector B averaged 288 psi. This ranged from 75 psi at
 Sample Location  B-19 —  an interface location of
 relatively poor overlap  (based on the mapping of the
 soil treatment locations by  LE) — to 579 psi at
 Sample Location B-23 - a location near the center of
 a primary column. In Sector  C, the UCS averaged
                                               53

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536 psi. This ranged from 247 at Sample Location C-
15, to 866 psi at Sample Location C-l, both column
centers. The average additive dosage rate in Sector C
(0.193 Ib additive/lb dry soil) was 13% greater than
in Sector B (0.171 Ib). Although in some  moisture
ranges a concentration change affects the UCS of
cement,  this was not  observed  at Hialeah.  In
addition, no effect of bulk density change on the UCS
was observed.  These  UCS  values are quite
satisfactory, easily meeting the EPA guideline
minimum of 50 psi [5] for this type of technology.

The permeability tests showed a reduction after soil
treatment from an average of 1.8 x  10-2 cm/s for
untreated soil to 4.2 x 10-7 cm/s for treated soils. This
treated soil value was slightly greater than the EPA
and industry guideline maximum  of 10-7 cm/s for
hazardous-waste-landfill soil-barrier liners. Not only
does a low permeability reduce  contaminant
mobility, but it lessens solid erosion and weathering
degradation.  This four-  orders-of-magnitude
decrease in permeability should divert  all
groundwater around the treated monolith.

The wet/dry weathering tests  showed low weight
losses, with the absolute losses about 0.3-0.4%. The
relative  weight losses,  compared to the control
specimen, were  about  0.1%.  However, the
freeze/thaw results were not satisfactory. Half of the
samples tested had relative weight losses of more
than 3.0%, the maximum being 30.7%. The weight
losses of the control samples for these tests were
0.3%-0.5%. UCS tests on about half of the weathered
samples showed that the strength was equivalent to
unweathered samples, except when the relative
weight loss exceeded 3.0%. Many of the samples from
the freeze/thaw tests with high weight losses
crumbled at the start of UCS testing. Permeabilities
for wet/dry and freeze/thaw samples with  moderate
weight losses were equal to the  unweathered
samples.

The microstructural studies, using scanning-electron
and optical microscopy and X-ray diffraction
analyses, found  the  treated soil  to be dense,
homogeneous, and of low porosity. Variations in the
vertical and horizontal directions were absent.  Thus,
it was concluded that the Geo-Con mixing operation
was efficient and  that  a solidified  mass with a
potential for long-term durability can be produced.

Formulation tests were also performed in the
laboratory, where 3 solidified samples  were
prepared. They used uncontaminated  soil and
composite soil samples from Sectors B and C with
Type  1 Portland cement,  instead of HWT-20,  at
dosage rates of 0.15 and 0.20 Ib/lb dry  soil. The
results showed the bulk densities were equivalent to
those of the treated field samples.  The UCS values
doubled  when  the dosage rate  of cement was
increased from 15% to 20% of the contaminated soil.
The UCS values for the contaminated soils were
about equal to or greater than the values for  field
samples, and the moisture content was lower, which
may have contributed to the higher UCS values.

Chemical Results

Both soil and leachates  were analyzed for PCBs,
volatile organics and heavy  metals. The leachate
results  were  compared to the corresponding soil
compositions.

The  untreated soil  contamination  consisted
primarily of PCBs (Aroclor 1260), with one localized
area in Sector B of VOCs and heavy metals. High
PCB concentrations were measured in Sector B,  with
the maximum being 950  rag/kg, compared to the
5,700  mg/kg value reported by IWT in Appendix B.
Other  minor  discrepancies between information
reported in Appendix B and actual results also exist.
The maximum PCB  concentration measured in
Sector C was  150 mg/kg.  After soil treatment, the
concentrations in Sector B were reduced on average
by a factor of about 4, providing a maximum treated-
soil concentration of 170  mg/kg. In Sector C, the
reduction was only about 25 wt%. This indicates that
soil blending during the additive injection operation
produced large reductions in  concentrations for the
samples in Sector B, indicating that the high  PCB
concentrations measured were localized. Even
greater concentration reductions after soil treatment
were observed for heavy metals and VOCs. Analyses
for VOCs  did not provide any evidence of PCB
decomposition, which was claimed by IWT. As noted
above, the microstructural analyses showed a
homogeneous mass, indicating  good vertical and
horizontal blending.

The treated-soil leachate analyses for PCBs showed
all values below the nominal detection limit (for SW-
846 Method 8080) of 1.0 ug/L. However, when
analyses of 7  treated-soil leachates from the more
contaminated areas were repeated at a reduced
detection limit of 0.1 pg/L, four samples were found
to be below the new detection limit, with the others
0.2 ug/L or less. This  compares to untreated soil
samples, which had leachate values up  to 13.0  ug/L
(there was one apparent wild point at 400 ug/L).

Additional information contributing  to  the
determination of PCB  immobilization  follows. All
untreated soil samples (with soil compositions at or
above 300 mg/kg) had measurable  leachate
compositions (above  1.0 mg/L). All untreated soil
samples of less than 60 mg/kg had leachate  PCB
concentrations below detection limits.  For  the in-
between untreated  soil  concentrations, some
leachate had PCB levels above the detection limit
(1.0 ug/L), while others did not. All treated soil  PCB
compositions were 170 mg/kg or less, with  most of
                                               54

-------
them below 100 mg/kg. Twelve samples analyzed
using Leach Tests  MCC-1P and  ANS 16.1  all
produced leachates with PCB concentrations below
the detection limit (1.0 ug/L). TCLP leach tests on
the 4 contaminated formulation samples produced
leachate concentrations for PCBs below the detection
limit of 1.0 mg/L. Therefore, it appears that the
HWT-20 additive may have immobilized the PCBs,
but since all the leachate concentrations, from both
untreated and treated soils,  were so close  to the
detection  limit, more  information  at higher  soil
concentrations is required to confirm this conclusion.

The untreated soil with high VOC concentration was
located near a former buried drainage drum.  The
designations for these samples are B-6, B-7 and B-8,
which are samples collected in one location at three
different depths  - 1-2 ft, 7-8 ft and 11-12 ft below
grade. Three VOCs were identified — total xylenes,
ethylbenzene and chlorobenzene — with the xylenes
found in the greatest quantities. The  maximum total
VOC concentration in the untreated soil was 1,485
mg/kg at  Location B-6.  After treatment, the VOC
concentrations were reduced sharply to a maximum
total concentration of 41.3 mg/kg  at B-6, with each
component reduced approximately in the same ratio.
This reduction was probably  due  to soil blending.
However,  some other factors - such as volatilization
of VOCs to the atmosphere and excessive holding
time of the samples in the laboratory before analyses
— may have contributed significant reductions.

Immobilization of VOCs could not be determined,
since only 3 samples were measured, and the treated
soil TCLP leachates  were quite low, mostly below
100 ug/L (except for xylenes, which were about,300 to
400 ug/L). Meanwhile, the untreated soil  TCLP
leachates  were about 10 times larger for each VOC
component, with the maximum total VOC leachate
concentration being about 4.4 mg/L. IWT claims that
their HWT-20 additive used in this  test was  not
tailored to immobilize VOCs.

The heavy metals, lead, chromium, copper and zinc,
were also detected only at Sample Locations B-6, B-7,
and B-8.  The maximum  total concentration  was
5,000 mg/kg at B-6,  with lead representing about
half of the total metals in the untreated soil. A lower
proportion of lead was observed in the treated soil
samples.  The maximum total-metals concentration
in the treated soil was only 279 mg/kg, also at B-6.
This soil  concentration change after  treatment is
very large, which tends to confirm that the reduction
in treated soil concentrations was due primarily to
soil blending with low contamination areas.  The
laboratory methods for metals analysis consists of an
acid digestion  procedure  followed by Atomic
Absorption spectroscopy,  which will measure each
metal, whether or not it was bonded to the additive.

TCLP leachate analyses for  total heavy metals in
untreated soils ranged from 0.32 to 2.65 mg/L, with
zinc showing the highest concentrations and the
other  3 metals comprising 30% or less. The treated
soil leachates contained very low concentrations of
metals, with individual metals at 100 mg/L or less
and the total metals concentration ranging from 120
to 210 mg/L. Since only 3 samples are available and
the leachate values are low, any immobilization of
metals cannot be determined. IWT claims  that their
HWT-20  additive was not tailored for immobilizing
metals.

The results of the chemical  analyses are  shown in
Tables C-6 through C-9 at the back of this Appendix.

Operations

Geo-Con's equipment  operations during the
demonstration were satisfactory,  although  some
problems were encountered.  These  difficulties were
minor, and with engineering design changes many
could have been avoided. The problems were, as
follows:

  • Automatic control of the feed streams (water
    and HWT-20)  to  the  auger could  not be
    maintained. Eventually manual control was
    required. This was caused in  part by the fact
    that the additive feed  system was  oversized
    because it was designed for a 4-auger machine.

  • Flow surges of additives were encountered on
    many soil columns. The remixing of the soil and
    additive on the auger upstroke tended to reduce
    any impact this may have had on treated soil
    properties.

  • A water leak in the auger head occurred, which
    restricted the use of supplemental water on the
    last 21 soil columns. GE instructed Geo-Con to
    continue operations to minimize time loss. An
     impact on the physical and chemical properties
    of the treated soil was not observed.

  •  Positioning of the auger  deviated  from the
     targeted locations, producing  some untreated
    areas between soil columns.

  •  Difficulties were encountered in aligning the
     auger to  start many  of  the columns,
     particularly in Sector C. These difficulties
     produced delays of a few min up to 40 min.
                                                55

-------
Table C-1. Physical Properties of Untreated Soils - Sector B
Sample
designation(a)
B-1
B-2
B-3
B-4

B-5
B-6
B-7
B-8
B-9
B-10
B-11
B-1 2

B-1 3

B-1 4
B-15

B-1 6
B-1 7

Moisture
• content
%
2.8
3.0
6.4
4.4
4.7
3.6
13.3
13.3
16.8
24.8
6.3
34.9
15.6

22.5

3.2
9.7

7.5
12.4
12.3
Bulk density
g/mL
1.50
1.56
1.21
1.41
1.55
1.28
1.46
1.74
1.85
1.59(C)
1.25
1.58
1.52
1.63
1.46
1.73
1.52
1.83
1.46
1.30
1.85
1.32
PH
-
7.7
8.4
7.6
7.5
7.3
11.2
8.3
8.1
7.8
8.5
7.8
8.1

7.8

7.7
8.1

7.9
8.2
8.3
Oil & grease
%
<0.1
0.1
<0.1
0.1
<0.1
0.1
0.8
1.6
0.4
<0.1
<0.1
0.2
<0.1

. 0.3

0.1
0.8

0.1
0.8
0.7
TOG
mg/kg
2,100
1,300
2,900
2,500
1,600
2,600
16,000
12,000
3,100
< 100
< 100
8,100
920

1,500

320
960

11,000
9,900
9,400
Permeability x
102cm/s(b)
1.6
1.0
1.0
0.76
0.50
1.2
1.4
6.0
0.98
0.15
2.6
0.05
0.91

0.05

0.98
2.1

3.7
0.13
0.55
(a)   Sample depths
     B-1, 2, 3, 4. 5, 6, 10, 14, 16 at 1-2 ft
     B-7, 11, 15, 17 at 7-8 ft
     B-8, 12 at 11-12 ft
     B-9, 13 at 16-17 ft
(b)   Each value shown is the permeability multiplied by 102. For example, the B-1 permeability is I.6xl0-2, and when
     multiplied by 102 is reported as 1.6.                                                  .
(c)   Modified bulk-density test using split spoon.
                                                       56

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Table C-2. Physical Properties of Untreated Soils - Sector C
Sample
designation(a)
C-1
C-2
C-3

C-4
C-5
C-6
C-7
C-8

C-9

C-10
C-11
C-12
C-13
C-14
"
C-15
C-1 6
C-1 7

Moisture
content
16.7
14.6
17.1
14.8
9.1
9.1
5.7
20.2
14.7

5.9

8.2
19.5
5.7
12.5
23.5

5.3
15.1
23.2

(a) Sample depth
C-6, 9, 12, 15 at 1-2 ft
C-1, 2, 3, 4, 5, 7, 10, 13, 16 at
C-8, 11, 14, 17 at 11-12 ft
(b) Modified bulk-density test using
Bulk density
g/mL
1.37
1.29
1.67

1.41
1.28
1.46
1.74
1.85
1.60
1.60
1.74
1.63(b)
1.39(b)
1.63
1.82
1.63
1.59(b)
1.66
1.20
1.65
1.60(b)
7-8 ft
split spoon.
Oil & grease
pH %
8.6 0.4
8.5 <0.1
8.2 0.4
8.2 0.2
8.7 0.2
8.3 0.2
8.6 <0.1
8.5 <0.1
8.4 <0.1

8.6 <0.1

8.5 <0.1
8.5 
-------
Table C-3. Physical Properties of Treated Soils - Sector B
Moisture Permeability
Sample content Bulk density Compressive 107
designation % g/mL strength, psi cm/s(h)
B-1 15.7
B-2 9.9

B-3 20.3
B-4 17.6
B-5 31.1
B-6 23.1
12.9
B-7 24.7
B-8 19.0
B-9 15.5
B-10
B-11 12.9
B-1 2
B-1 3
B-14 20.2
B-1 5 21.2
B-1 6 26.5
B-1 7 13.3
B-1 8
B-19 19.1
B-20 17.6
B-21 18.1
B-22 20.9
22.9
B-23 17.2
B-24 20.1
1.78
1.72

1.74
1.81
1.66
1.77
1.75
1.81
1.88
1.96
-
2.24
2.15
-
1.78
1.83
1.81
1.82
--
1.58
1.79
1.92
1.99
1.76
1.98
1.90
492
330
508
172
206
86
114
115
173
303
470
--
321
204
--
221
256
413
507
-
75
199
479
428
177
579
351
1.4
...

3.3
0.8
2.3
4.2

21.0
5.9










11.0
2.6
8.3
4.1

3.5
3.5
Weathering tests
wt. loss % (a)
X
W/D
0.38
0.32

0.37
0.42
0.37
0.43
0.49 '

0.34
0.53




0.44
0.40

0.26


0.46
0.39(b)
0.39(C)

0.27
0.41
F/T
0.65
1.48.

2.07
3.34

1.84

3.04
27.92
29.53




1 .66(f)
6.06(g)
4.37
1.10


0.87
1.34(d)
6.05(6)

23.28
10.73
(a) Reported as % loss of starting weight on a dry basis. The weight losses of the wet/dry (W/D) and freeze/thaw (F/T)
controls were 0.3-0.4%.
(b) Permeability after 1 2 W/D weathering cycles = 2.7x1 0-7 cm/s.
(c) Permeability after 1 2 W/D cycles = 4.9x1 o-7 cm/s.
(d) Permeability after 1 2 F/T cycles = 8.9x1 o-8 cm/s.
(e) Permeability after 12 F/T cycles = 1 .2x1 0-7 cm/s.
(0 Permeability after 12 F/T cycles = 3.9x1 0-8 cm/s.
(g) Permeability after 1 2 F/T cycles = 5.9xtO-7 cm/s.
(h) All values shown are the permeability multiplied by 107. For example, B-1 permeability is i.4xlO~7, and when multiplied
by 1 07 is reported as 1 .4
                                                   58

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Table C-4. Physical Properties of Treated Soils - Sector C
Sample
designation
C-1
C-2
C-3

C-4
C-5
C-6
C-7

C-8
C-9
C:10
C-11
C-12
C-1 3
C-14
C-15
C-16
C-1 7
C-l 8
Moisture
content
%
18.8
14.3
20.9
17.9
20.2
14.6
12.3
16.7
20.0
15.9
20.8
18.9
19.7
23.8
15.5
13.5
18.0
15.4
16.7
16.1
Bulk density
g/mL
1.97
1.93
1.95
2.01
1.96
1.95
1.91
1.82
1.91
2.00
1.95
1.93
1.97
1.84
1.99
1.99
1.80
2.02
2.02
1.91
Compressive
strength, psi
866
528
482
611
656
294
567
343
524
813
460
466
783
409
553
636
247
435
521
530
Permeability x
10?
cm/s (d)
0.24





1.0
6.4

4.1



1.6
1.9
2.2

4.6
2.5

Weathering
wt loss %
W/D
0.35
0.41
0.27
0.31
0.38
0.40
0.34
0.31
0.38
0.39
0.32
1.68
0.27
0.40
0.25
0.31
0.33
0.30
0.29
0.32
tests
(a)
FIT
2.06
8.11
3.94
30.75
2.53
3.12
1.65
1.97(b)

0.72
1.70
0.88
0.99(C)
4.20
8.04
20.98
2.14
2.57
2.95
14.45
(a)   Reported as % loss of starting weight on a dry basis. The weight losses of the controls were 0.3-0.4%.
(b)   Permeability after 12 F/T cycles =  2.3x10-7 cm/s.
(c)   Permeability after 12 F/T cycles =  3.0x10-8 cm/s.
(d)  All values shown are the permeability multiplied by 107. For example, C-8 permeability is 4.1x10-7, and when multiplied by 107
     is reported as 4.1.
  Table C-5. Results of Formulation Studies
Addition Rates
Clean Soil .
Property
Slump flow, %
Moisture content, %
Bulk density, g/mL
UCS, psi
TCLP PCBs (Aroclor1260), i»g/L
15%
cement
139.8
3.6
2.01
740
20%
cement
102.8
4.0
2.02
1,770
Sector B
15%
cement
58.1
5.1
2.01
1,332
20%
cement
79.7
5.0
2.03
<1 0
Sector C
15%
cement
129.7
8.9
1.88
170
20%
cememt
116.5
8.9
1.81
318
                                                          59

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Table C-6. PCBs in Soils and Leachates - Sector B
                                        *
                                               PCB concentration
Sample
designation
B-1
B-2
B-3
B-4


B-5
B-6


B-7

B-8
B-9
B-10
B-11

B-12
B-13
B-14
B-1 5
B-1 6

B-17


B-1 8
B-1 9
B-20
B-21
B-22

B-23
B-24
Untreated soil
mg/kg
52
74
55
88
78

16
650


460

220
16
1.1
950

140
250
26
63
300

490
500

-
--
--
--
-

--
--
Untreated soil TCLP
leachate, ng/L
< 1.0
1.2
1.0
1.1
1.6
(0.62)
< 1.0
12.0

(15)
400.0
(250)
< 1.0
< 1.0
< 1.0
7.2
(0.33)
1.1
< 1.0
< 1.0
13.0
3.7
(0.50)
4.2
1.8
(1.0)
-
~
~
--
-

--
--
Treated soil
mg/kg
40
53
40
41


18
35
63

82

9.6
< 1.0
--
170

16
-
11
7
100

100


~
97
50
60
- 130
98
<1.0
1.6
Treated soil TCLP
leachate, yg/L
<1.0
<1.0
<1.0
<1.0

(<0.1)
<1.0
<1.0
<1.0
(0.15).
<1.0
(0.12)
<1.0
<1.0
--
<1.0
(<0.10)
<1.0
"
<1.0
<1.0
<1.0
(<0.10)
<1.0
(<0.20)

--
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
() Repeat analyses of existing TCLP leachates analyzed to a detection limit of 0.1 ng/L. Original analyses
performed to a detection limit of 1.0 jig/L.
                                              60

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Table C-7. PCBs in Soils and Leachates - Sector C
                                             PCB concentration
Sample
designation
C-1
C-2
C-3

C-4
C-5
C-6
C-7

C-8
C-9
C-10
C-11
C-1 2
C-1 3
C-14
C-1 5

C-16
C-1 7
C-1 8
Untreated soil
mg/kg
98
2.5
96
92 -
9.1
27
16
150

15
17
86
16
23
32
1.8
80
46
13
< 1
-
Untreated soil TCLP
leachate, ng/L
< 1.0
< 1.0
< 1.0

< 1.0
< 1.0
< 1.0
< 1.0

< 1.0
< 1.0
< 1.0
1.3
< 1.0
< 1.0
< 1.0
< 1.0

< 1.0
< 1.0
-
Treated soil Treated soil TCLP
mg/kg leachate, ng/L
20 < 1 .0
19 <1.0
110 <1.0
3.5 < 1 .0
40 < 1 .0
22 < 1 .0
26 < 1 .0
16 <1.0
27 < 1 .0
5.9 < 1 .0
20
80 < 1 .0
45 < 1 .0
4.7 < 1 .0
1 .2 < 1 .0
1 .0 < 1 .0
17 < 1 .0

6.0 < 1 .0
< 1.0 <1.0
7.1
( ) Repeat analysis of existing TCLP leachate analyzed to a detection limit of 0.1
                                             61

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Table C-8. Total Volatile Organics in Soils and Leachates
Sample designation (a)
B-6
Total xylenes
Chlorobenzene
Ethylbenzene
Total
B-6d(b)
Total xylenes
Chlorobenzene
Ethylbenzene
Total
B-7
Total xylenes
Chlorobenzene
Ethylbenzene
Total
B-8
Total xylenes
Chlorobenzene
Ethylbenzene
Total
Untreated soil
mg/kg

1,300
65
120
1,485

—
—
—


560, 1000(0)
20, 150
74, 28
916 avg.

140, 190(c)
5, 7
13, 	 23
1 89 avg.
Untreated
soil leachate
ng/L

3,700
280
440
4,420

—
—
—


6,600
290
1,000
7,890

2,100
100
290
2,490
Treated soil
mg/kg

35.0
1.9
4.4
41.3

32.0
2.2
4.6
38.8

34.0
2.5
4.5
41.0

1.7
<1.2
0.66
2.4
Treated
soil leachate, „
ng/L

30
<5
<5
30

<13
<13
<13
<13

430
54
120
604

270
19
36
325
(a)   Depth of samples; B-6 at 1 -2 ft; B-7 at 7-8 ft; and B-8 at 11 -12 ft.
(b)   Duplicate.
(c)   Values shown represent two soil analyses.

Table C-9. Total of Four Priority Pollutant Metals in  Soils and Leachates
Sample designation"
B-6
Chromium
Copper
Lead
Zinc
Total
B-7
Chromium
Copper
Lead
Zinc
Total
B-8
Chromium
Copper
Lead
Zinc
Total
Untreated soil
mg/kg

400
910
2,500
1.000
4,810

43
70
310
240
663

84
59
280
190
613
Untreated
soil leachate
H9/L

10
240
200
2.200
2,650

10
20
<50
290
320

10
20
100
300
430
Treated soil
mg/kg

50
39
140
50
279

47
12
55
80
194

46
6
11
17
80
Treated
soil leachate,
HQ/L

40
60
70
40
210

40
50
<50
30
120

30
40
<50
100
170
* Depth of samples: B-6 at 1 -2 ft; B-7 at 7-8 ft; and B-8 at 11 -12 ft.
                                                      62

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                                 Appendix D

                                Case Studies

Data in this Applications Analysis Report have been quoted from case studies provided by IWT
and GE. A summary of each of these sources is included in this appendix and designated below.

D-l Report of Initial Bench Scale Testing Solidification/Fixation Agent Evaluation, 8/86

D-2 Letter Report: Report on Chemical and Physical Laboratory Analyses for Bench Scale
    Specimens, 10/10/86

D-3 Data Sheets from Southwestern Laboratories

D-4 Presentation of the HWT Chemical Fixation Technology  and Japanese  In-Place
    Treatment Equipment

D-5 Advanced Chemical Fixation of Organic and Inorganic Content Wastes

D-6 Economic Analysis: Letter from Geo-Con, Inc. to Foster Wheeler Enviresponse, 8/30/88
                                        63

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                                     Case Study D-1
Law Environmental Report  to General Electric: Report of Initial Bench Scale Testing
Solidification/Fixation Agent Evaluation

Description

A laboratory study was conducted by Law Environmental for General Electric to determine
the effectiveness of the International Waste Technologies HWT-20  additive. Thirty-gallon
samples from the quartz/sand top-soil layer were collected, based on high, medium or low
concentrations of PCBs. The average concentrations of these samples were 5,628, 1,130, and 83
ppm PCBs, respectively. In addition, a sample was collected from a limestone layer (5-10 ft
below grade), which had a concentration of 73 ppm PCBs. From each of the four 30-gal soil
samples, 3 specimens were taken for laboratory analysis of total PCBs.

For each of the three 30-gal sand-samples, 6 batches (18 total) were  prepared; on treatment
with the additive, each batch filled 10 molds, 3 in. dia. by 6 in. long. From the limestone
sample, 2 batches were prepared. Each batch prepared (total of 20) used a different additive
concentration,  ranging from 0.03 to 0.25 Ib/lb dry soil, at a different moisture  range,
representing soil either above and below the water table.

Testing Protocol

The following physical tests were performed on untreated soil samples:

Particle size distribution	ASTM D-421-85 and D-422-63

Permeability (constant head) ...ASTM D-2434-68 (reapproved 1974)

Moisture-density relation	ASTM D-698-78, Method A

Moisture content	ASTM D-2216-80

Chemical  analyses of the soil samples were performed using EPA SW-846 Method 3550 for
sample preparation, and Method 8080 for PCB analyses.

Four different leaching procedures were used to evaluate the effectiveness of the HWT-20
additive:

EP Toxicity (standard) with membrane filter.

EP Toxicity with glass fiber filter.

EP Toxicity with glass fiber filter and site water plus sulfurous acid (pH = 5) as the leaching
medium.

Toxicity Characteristic Leaching Procedure (TCLP) using extraction fluid #2.

Major Conclusions

No conclusions are presented in this document.
                                         64

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Data Summary

The measured physical properties on the untreated soils were:

Particle size distribution — Typical for Hialeah area (distributions not provided)

Compaction test -- Maximum dry density 103 Ib/ft3 at an optimum moisture content of 10 wt%

Permeability — 7.4 x 10:3 cm/s (one sample)

The leachate results for the 4 leach tests of pre- and posttreatment samples were as follows:


                                          Leachate results, pg/L(a)
Untreated soil
concentration
mg/kg
1,130
1,130
5,628
5,628
73 (b)
Addictive rate
Ib/lb dry soil
0.15
0.18
0.05
0.25
0.15
EP Tox,
membrane
3.0/1.2
2.0 / 2.0
7.0 / 7.0
2.0 /< 1.0
<1.0/<1.0
EP Tox,
glass fiber
54 / 10
54/3
39/39
39/4
5/<1.0
EP Tox,
site water
13/2.6
13/5.5
65/98
65 / 32
4/<1.0
TCLP
10 /28
10/14
33/119
33/170
1 .3 /3.0
(a) Pretreatment/posttreatment
(b) Limestone
The EP Toxicity (EP Tox) tests showed reductions in PCBs in the leachate of the treated soil
samples compared to that of untreated soil samples over and above that which would occur
from dilution from the additive. The TCLP leachates for the treated soils all had higher PCB
concentrations than the untreated soil. Law Environmental had no explanation for the latter
results.

In addition, LE found that there was an optimum ratio of weight-of-additive/weight-of-water
for maximum treatment effectiveness. This value is in the range of 1.0 to 1.5. Since there was a
consistency among the 3 EP Tox tests, the validity of the  EP Tox results, compared to the
TCLP results, is enhanced.
                                          65

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                                        Case Study D-2
Law Environmental Letter Report to General Electric: Report on Chemical and Physical
Laboratory Analyses for Bench Scale Experiments
Description
The description provided for Case Study D-l is applicable here.
Testing Protocol
This work consists of analyses that were part of Case Study D-l, but issued subsequent to the
initial report. The results provided are for the treated-soil physical properties,  which were not
included in the first case study. The following physical tests were performed on treated soil
samples:
Moisture content	ASTM D-4216
Dry unit weight	Weight/volume
Permeability (falling head)	"Test method for solid waste characterization," Section 13
- Unconfined compressive Strength... ASTM D-2216-80
Major Conclusions
No conclusions presented.
Data Summary
          Additive  rate
          Ib/lb dry soil

             0.15
             0.10
             0.20
             0.10
             0.15
             0.18
             0.25
             0.15 (c)
             0.15 (d)
Mositure content
 before/after, %

   7.6 / 2.8
   9.5 / 5.4
   10.1  /4.1
 24.4/13.1 (b)
 24.5 /13.6 (b)
 20.9/11.4 (b)
 19.7/9.8 (b)
 19.8/9.6 (b)
   24.5 / -
Density dry
  Ib/fl?
UCS(a)
  psi
99.3
103.2
102.8
92.1
92.5
108.5
116.4
115.4
92.7
198
310
299
367
714
1,223
2,127
1,899
—
Strain at failure, %

     0.427
     0.351
     0.347
     0.373
     0.472
     0.737
     1.07
     0.936
        (a)  All height-to-diameter ratios were 2.1 except in the first test, which used a ratib of 1.9.
        (b)  Moisture content simulating values found below watertable.
        (c)  Limestone - all other samples are treated quartz sand.
        (d)  Permeability was 7.6 x 10'8 cm/s.

Some additional treated-soil leachate results were provided subsequent to this letter report. In
these tests, the  HWT-20  was added as  a slurry to the soil from the same 30-gal batches of
contaminated soil as described  in Case  Study D-l (previous tests used dry additive) to more
closely simulate field operations. The results were as on the next page:
                                             66

-------
Average PCB concentration in
untreated soil, ppm
1,130
5,628
5,628
5,628
5,628
Additive rate
Ib/lb dry soil
0.15
0.15
0.1 5(a)
0.20(a)
0.1 5(a)
Average PCB
concentration in
treated soil, mg/kg
893
3,942
2,844
3,261
2,929
EP Tox leachate
H9/L
2.45
4.15
4.46
4.13
2.84(b)
(a) Moisture content simulating below watertable.
(b) Used EP Tox with glass fiber filter, substituting site water (no PCBs) for de-ionized water in the
     extraction. All EP Tox tests replaced the standard membrane filter with a glass fiber filter.
                                               67

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                                       Case Study D-3
Data Sheets from Southwestern Laboratory
Description
Samples were collected from 2 core borings by LE during the demonstration. One boring was at
an anticipated poorly tested area (B-3) — based on information compiled by LE on Geo-Con
auger-injection locations — and the other was near a treated-soil column center (B-2). Samples
were collected at level increments of 18 to 24 in. and analyzed for PCBs. TCLP leach tests were
then performed on each sample with PCB concentration measured to a detection limit of 0.1 ug/L
Testing  Protocol
The  samples were cured for approximately 2 weeks before the TCLP leach tests were performed.
The  leachate analyses were performed 7 days after the extraction.
Major Conclusions
No conclusions are provided with the data.
Data Summary
          Sample
        designation(a)
Depth, ft
PCBs in soil,
  mg/kg (b)
PCBs in TCLP
leachate, jig/L
           B-2                  3.0- 3.6                   34.9               1.20
           B-2                  5.0- 5.75                  182.0             <0.10
           B-2                  7.0 - 7.8                  206.0               0.22
           B-2                  9.5-11.0                  166.0               0.12
           B-2                 12.5-14.0                   32.8             <0.10
           B-2       '          15.5-17.0                   13.7               0.11
           B-3                   1.5 - 3.0                   22.8             <0.10
           B-3                   3.0- 4.5                   47.7             <0.10
           B-3                   6.0- 7.5                   72.7             <0.10
           B-3                   7.5 - 9.0                   57.4             <0.10
           B-3                  10.5-12.0   .                 2.0             <0.10
           B-3                  13.5-15.0                    1.0             <0.10
           Blank                     —                      <1.0             <0.10
    (a)  These designations are those of LE and are not related to those reported earlier in this report.
    (b)  PCBs - Araclor 1260
                                            68

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                                     Case Study D-4
Presentation of the HWT Chemical Fixation Technology and Japanese In-Place Treatment
Equipment

Description
This is an informal report prepared by IWT describing the technology. In the report, IWT claims
that their HWT components have the physical characteristics of sorption, where all free water is
absorbed, and  of pozzolan-Portland cement  where micro-encapsulation occurs in conjunction
with the chemical alteration of the toxic character of the waste. This stabilization, they say, is a
technological improvement over the successful approaches that have been used by the Japanese
since 1970 on large-scale waste cleanups.

It is claimed that  the HWT set of chemical fixation products generate complex crystalline
inorganic-polymers. These macromolecules are made up of selected polyvalent  inorganic
elements that react in a polyfunctional manner, producing branched and cross-linked polymers
of sufficient density to cause some interpenetrating-polymer-network (IPN) bonding. These
polymers are said to have a high resistance to acids and other naturally existing deteriorating
factors. Structural bonding in the polymer is  mainly covalent. There is a two-phased reaction in
which the toxic elements and compounds are complexed first  in a fast reaction, and  then
permanently complexed further in the building of macromolecules, which continue to generate
over a long time.

The first part of the chemical fixation generates irreversible colloidal structures and ion
exchanges with toxic metals and organics by special intercalation compounds. Phase two is the
generation of the macromolecule  framework.  This is  also a relatively irreversible  colloid
synthesis, which is a slower-moving reaction going from soil-mix to gel, to crystalline, three-
dimensional inorganic polymer. The treated material should be able to pass  the required
leaching tests within 7 to  28 days. By varying the composition of the HWT treatment
compounds, the bonding characteristics  and durability of the structure are varied to suit a
particular waste situation and desired leaching standards.

This paper also describes various in situ technologies used in Japan. The original plan  of IWT
was to use the JST Method of deep-soil-mixing of Japan National Railways and Sanwa Kizai
Co., Ltd. This was subsequently changed to the Geo-Con, Inc., deep-soil-mixing equipment.

Testing Protocol
The earliest leach tests performed by IWT for wastes treated with HWT-20 are described. These
tests included:

                  EP Toxicity for PCBs
                  Hexane Extraction for Pentachlorophenol (PCP)
                  TCLP for K051, API separator bottoms
                  TCLP for a sludge containing 70% water
                  TCLP for a liquid waste

The hexane extractions show the amount of available contaminant that can be released from the
waste. IWT is claiming that chemical bonding exists between HWT-20 and the contaminants,
and if hexane or methylene chloride cannot extract it, then it is bonded and unavailable to
leaching also.

Major Conclusions
No conclusions are presented in the document.
                                          69

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Data Summary
Contaminants
PCB
PCB
PCB
PCB
POP
PCB
PCB
PCP
POP
PCP
Concentration
in waste, mg/kg
1,140
1,140
6,000
6,000
11,000
1,800
9,200
290-500
290-500
290-500
Type of
waste
Soil
Soil
Soi
Soil
Soil
Oily liquid
Oily liquid
Soil
Soil
Soil
Extraction
test
EP-Tox
Hexane
EP-Tox
Hexane
Methylene chloride
EP-Tox
EP-Tox
Hexane
Hexane
Hexane
HWT-20
additive,
Ib/lb dry
0.15
0.15
0.25
0.25
0.15
0.20
0.20
0.05
0.10
0.15
Cure
time,
days
14
14
28
28
14
3
3
28
28
28
Extractant
concentration,
mg/L
0.006
355
0.00008
1,300
450
0.069
0.337
38
2.3
0.26
 Cr                        630         K051           TCLP
 Pb                        332         K051           TCLP
 Ethylbenzene                10          K051           TCLP
 Xylenes                    83          K051           TCLP
 Anthracene                 19          K051           TCLP
 Chrysenene                 29          K051           TCLP
 Meihylnaphthalene           470          K051           TCLP
 Naphthalene                 93          K051           TCLP
 Phenanthrene              206          K051           TCLP

 Acrylonitrile               120         Sludge          TCLP
 Acrylic Acid                 5         Sludge          TCLP
 Acrolein                    59        Sludge          TCLP
 Acetonitrile                150         Sludge          TCLP
 Cu                        78         Sludge          TCLP
 Sb                        13         Sludge          TCLP

 Vinyl chloride             1,671          Liquid          TCLP
 Trichloroethylene         11,200          Liquid          TCLP
 Trichloroethylane          3,800          Liquid          TCLP
 Tetrachloroethylene        5,900          Liquid          TCLP
0.15-0.25
0.15-0.25
0.15-0.25
0.15-0.25
0.15-0.25
0.15-0.25
0.15-0.25
0.15-0.25
0.15-0.25

    0.15
    0.15
    0.15
    0.15
    0.15
    0.15
    0.33      28
    0.33      28
    0.33      28
    0.33      28
0.03-0.04
     0.05
   <0.01
   <0.01
   <0.01
   <0.01
   <0.01
   <0.01
   <0.01

      1.5
      0.1
      0.5
      3.9
      0.2
      0.7

      ND
      ND
     ND
      ND
"Not provided.    ND = Nondetected; detection limit not defined.
The PCB and PCP tests show that only a small fraction of these contaminants are extracted by hexane or methylene
chloride.
The PCB and PCP tests show that only a small fraction of these contaminants are extracted by
hexane or methylene chloride.
                                                 70

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                                     Case Study D-5
Advanced Chemical Fixation of Organic and Inorganic Content Wastes

Description
This is an informal IWT report, a followup to the one described in Case Study D-4. It describes
test results using a more-advanced additive called HWT-22. The paper describes IWT's view of
the mechanisms for the additive bonding to the contaminants. Results are also presented from
various extraction tests and from infrared  scanning and differential scanning calorimetry
(DSC). These latter tests are performed to show changes in the treated waste  structure. The
infrared scanning shows shifts in vibrational frequencies between atoms, and  DSC measures
changes in energy and temperature to release the contaminants from the soil.

IWT claims a number of unique properties associated with the additives, which are:

  •  The inorganic polymer network can be used as a durable medium with a wide range of types
     of bonding with organics and inorganics.

  •  An impact on cement hydration reactions that causes a more effective dispersion of
     treatment chemicals throughout the waste.

  •  Promotion of surfactant functions that promote microscopic homogeneity.

  •  Use of intercalation, or linking, compounds to interact with the organic toxins by a sorptive
     process. The intercalation compound can be sodium bentonite (or another clay) that has
     been reacted with a quaternary ammonium compound. The nature of the amine can be
     varied depending on the class of organic toxins to be immobilized.

The paper provides detailed discussion of the bonding mechanisms.

Testing Protocol
Two sets of extraction tests not included in Case Study D-4 are reported, one using TCLP and the
other using solvents of differing polarities. This latter test was performed to show the strength of
bonding of various contaminants of different polarity.

Various organic compounds were selected for a series of infrared and DSC experiments to better
understand the bonding mechanism. The infrared test measures bond lengths after waste
treatment and compares them to the bond length in the untreated contaminant. The DSC test
was performed to measure the energy necessary to release the compounds from the matrix.

Major Conclusions
The following conclusions are provided by IWT on its test work:

- There is true multiple bonding between HWT-22 and organic components of the waste.

- When heat is applied, many of the organics fragment into simpler molecules.

- The total energy to drive organics o.ut of the treatment mix is higher than their normal heats
  of vaporization.

- Gas chromatography/mass spectroscopy (GC/MS) data indicate that other bonding reactions
  are catalyzed by clay additives.
                                          71

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 -  The use of processed intercalation compounds chemically alters many classes of organics.
   These compounds, combined with cement, blend into a chemical fixation material that is a
   viable alternative to other more costly methods of waste treatment.
 Data Summary
 • The following TCLP leach-test results were obtained by adding 0.15 Ib HWT-20/lb dry waste
   (before thickening) to K049 slop oil emulsion, which also contained some K048, dissolved air
   flotation float from the refinery industry, and K051 API  separator bottoms. Kiln dust was
   added to the liquid waste on a 1/1 ratio to thicken before the HWT-20 was added. Curing time
   was 21 days, and a volume expansion of 25% was experienced.
Contaminant
Cr
Pb
As
Ba
Cd
Hg
Se
Ag
Cu
Zn
Concen-
tration
mg/kg
1.9
16.3
4.8
22.1
2.4
1.3
1.3
57.7
32.7
3.1
TCLP
leachate
concentration
mg/L
0.28
0.08
0.0009
1.4
0.04
0.08
0.005
0.07
0.06
0.005
Contaminant
Ni
V
xylenes
4-methylphenol
isophorone
2-nitrophenol
2,4-dinitrophenol
PCP
phenanthrene
anthracene
Concen-
tration
mg/kg
6.3
173.1
26,500
9.1
2,226
816
316
49
21
28
TCLP
leachate
concentration
mg/L
0.02
0.2
4,605
ND
8.5
1.3
ND
1.3
1.4
1.1
    ND = Not detected (detection limit not defined).
The results show that xylenes were leached at a very high rate. IWT changed the formulation to
HWT-21, and the new leachate concentration for xylenes dropped to 48 mg/L.
• The following extraction results were obtained by using solvents of various polarities. The
  higher the polarity index, the stronger the solvent.
                                      Solvent (polarity index)
                 Contaminant
Dimethylsulfoxide (7.2)     n-Butanol (4.0)    Iso octane (0.1)
                                              Extractopm concentration, mg/L
           4-Methylphenol
           Isophorone
           2,4-Dimethylphenol
           2-Nitrophenol
           Hexachlorobenzene
           PCP
           Anthracene
           Phenanthrene
           Methylnaphthalene
      10.0
    2,179
     207.5
     724
       0.15
      21.3
       3.3
       6.5
       0.22
5.5
1,213
116
361
0.10
13.7
4.7
3.9
0.12
1.9
695.3
29.0
91.4
0.24
5.6
22.8
19.2
0.84
The above table reveals that the greater the polarity of organic compound, the stronger the
bonding to the matrix.
                                            72

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  •  Results for the infrared analyses, showing the frequency  shifts for the various  bonds
     studied, are presented below:
Compound
Nitrobenzene


Phenol

Chloroaniline


Chloronaphthalene

Triethanolamine

Treatment material
frequency, 1/cm
1,150
1,720
2,929
934
3,632
662
2,348
3,542
660
2,611 ,
2,297
1,070
Shift from
untreated, 1/cm
-25
-22
- 5
-22
-8
22
6
-48
19
-37
193
-5
Peak assignment
Aromatic mono substitution
C-N stretch
C-H stretch
C-O stretch
H-bonded OH
C-CI stretch
C-H stretch
N-H stretch
C-CI stretch
C-H stretch
Amine salt formation
H bonding
Some of the numerical results from the DSC tests were:
               Compound

           Phenol
           Trichloroethylene
           Nitrobenzene
           Triethanolamine
   Literature value
for heat of vaporization
     kcal/mole

      11.89
       8.32
      12.17
      12.78
Observed heat
of vaporization
   kcal/mole

    38.13
    34.43
    18.6
    24.16
% Increase

  220.7
  314.2
   52.8
   87.8
Additional observations of IWT are:

- All compounds leave the matrix at more than one temperature.

- Total energy involved in the treated matrix was much higher than the heat of vaporization of
  the pure compounds.

- When the effluent gases were analyzed, neither the  original compound nor any of its
  fragments were seen.
                                            73

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                                     Case Study D-6
Economic Analysis: Letter from Geo-Con, Inc., to Foster Wheeler Enviresponse, Inc., 8/30/88

Description
Geo-Con provided cost information for remediating the Hialeah, Fla., site using either a 1-auger
or 4-auger machine. All costs provided include overhead and profit. The input is based on using
15 Ib HWT-20 additive/100 Ib dry soil.
    Cost Component, $/yd3
4-Auger
    Labor  	  22.00
    Equipment 	  28.00
    Subcontracts 	  6.00
    Other (purchases, insurance, health and safety)  	  9.00
    Materials (HWT-20) 	   85.00

    Mobilization/Demobilization, $

    Labor  	  26,000
    Equipment	  24,000
    Subcontracts (trucking, etc.) 	  18,000
    Other (purchases, insurance)  	  22,000

                                   Subtotal  	  90,000

    Capital Costs. $

    Augers  	  125,000
    Flow control system 	  132,000
    DSM drill	  368,000
    Leads  		  42,000
    Power Pack 	  84,000
1-Auger

  55.00
  70.00
  18.00
  25.00
  85.00
                    9,000
                    8,000
                   10,000
                    5,000

                   32,000
                   7,000
                   20,000
                     N/A
                     N/A
                     N/A
                                   Subtotal  	  751,000
                   27,000
                                          74

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                              References for Appendices
1.  Tittlebaum, M.E.,  et al.  State-of-the-Art  on
   Stabilization of Hazardous Organic Liquid
   Wastes and Sludges, in CRC Critical Reviews in
   Environmental Control,  Vol. 15, Issue 2, CRC
   Press, Boca Raton, Fla., 1985, pp. 179-211.

2.  Handbook—Remedial Action at Waste Disposal
   Sites.  EPA 625/6-85/006.   USEPA,  ORD,
   Cincinnati, Ohio and OSWER, Washington,
   D.C., 1985.

3.  Guide to the Disposal of Chemically Stabilized
   and Solidified Waste.  USEPA, SW-872 Revised.
   Municipal Environmental Research Laboratory,
   ORD, Cincinnati, Ohio, 1982.

4.  Technology Evaluation Report International
   Waste  Technologies In  Situ  Stabiliza-
   tion/Solidification,  USEPA ORD/RREL,
   Cincinnati, Ohio, 1989.

5.  Prohibition on the Placement of Bulk Liquid
   Hazardous Waste  in  Landfills—Statutory
   Interpretive Guidance. EPA 530-SW-86/016,
   OSWER, Washington, D.C., 1986.
                                             75

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