-------
     The  preliminary tests of single heavy-
metal treatment agents provided the opti-
mum concentration and optimum pH for EDTA
treatment.  The more concentrated solution,
0.1 M EDTA, is clearly more effective.  A
pH of 5 is probably as effective as pH 6,
but either is more effective than pH 7 or
above.

     The  two-agent tests demonstrated that
weaker agents do not remove any of the
metals of interest more efficiently than
EDTA alone.

     The  three-agent tests demonstrated
that EDTA, hydroxylamine hydrochloride, and
citrate buffer are all necessary for good
cleanup of the soil.  The EDTA chelates
and solubilizes all of the metals to some
degree; the hydroxylamine hydrochloride
probably  reduces the iron oxide-manganese
oxide matrix, releasing bound metals, and
also reduces insoluble chromates to chro-
mium (II)  and (III) forms; and the citrate
removes the reduced chromium and addi-
tional  acid-labile metals.  The chelating
agent/reducing agent/acidic citrate buffer
combination appears to be very effective
in heavy-metal cleanup.

     The three-agent test with just EOTA
demonstrated that cleanup of cadmium and
chromium is significantly better with the
sequential EDTA/hydroxylamine/ citrate
than with  three treatments of EDTA alone.
However, EDTA alone appears to be suffi-
cient for  removing the lead and copper;
although the nickel removal was poor with
EDTA alone, the treatment with all  three
agents  showed no better removal.

     The three-ayent test with hydroxyla-
mine hydrochloride first, followed by EDTA
and then citrate, demonstrated that the
use of a chelating agent following the re-
duction step does not improve the cleanup.
Effects of the Soil Characteristics on the
Cleanup Efficiency

     The efficient cleanup of the heavy-
metal contamination in the soil was prob-
ably facilitated by the low cation ex-
change capacity (CEC) of the soil.  How-
ever, the presence of iron and manganese
oxides apparently interferes with heavy
metal removal by EDTA;  reducing these
oxides was necessary to remove all the
cadmium.

Feasibility Studies Using Shaker and
Column Tests

     The shaker studies were quick and
effective screening tests for estimating
treatment-agent efficiency.  The column
tests, although more difficult and time-
consuming more closely represent the
behaviour that might be expected if the
agents were used for jjn situ cleanup of an
actual contaminated site.  The column tests
model cleanup under gravity flow conditions
through soil with a permeability somewhat
similar to the native soil.  If time had
permitted longer soil column tests, extrac-
tion efficiencies would probably have been
similar to the shaker table test results.
Both the shaker and column tests are very
useful for studying the feasibility of
potential soil cleanup agents.
REFERENCES

1.  Ellis, W. D., J. R. Payne, and G. D.
    McNabb.  1985 Treatment of Contamina-
    ted Soils with Aqueous Surfactants.
    EPA/600/S2-85/129  U. S. Environmental
    Protection Agency.

2.  Repa, E. W., E. F. Tokarski, and R. T.
    Eades.  1984.  Draft Final Report.
    Evaluation of the Asphalt Cover at the
    Western Processing. Inc., Superfund
    Site.  EPA Contract #68-03-3113.  U.S.
    Environmental Protection Agency.
                                            133

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134

-------
                  HYDROMETALLURGICAL TREATMENT OF SOIL
OJ
VJ1
                                  PRESENTED AT
            EPA'S WORKSHOP ON EXTRACTIVE TREATMENT OF EXCAVATED SOIL
                                  EDISON, N.J.
                                DECEMBER 1,  1988

                                       BY
                               WILLIAM B. SCHMIDT
                                      and
                              MEMBERS OF THE STAFF
                                 BUREAU  OF MINES
The Bureau of Mines is the Federal Agency responsible for a number
of major activities related to the minerals industry.  Among these
responsibilities  is  the performance  of research  on mining  and
metallurgical technologies.   This research has lead to a number of
major developments that have benefitted the industry and the people
of this country.  The 75 years of research and technical assistance
experience  has   also  resulted  in  the  Bureau   becoming  the
government's principal expert in the area of  selective extraction
of inorganic ions, i.e., technology to extract low concentrations
of  metals   and   other   inorganic  materials   from   their  host
environment.  This capability has applicability beyond the minerals
industry  to the  field  of  Superfund and RCRA remediation.   The
purpose  of  this  presentation  is  to  provide  a  little  more
information on the Bureau,  its interests and  capabilities, and to
look at ways in which the Bureau's expertise has been and might be
applied to the problems faced by EPA.

As indicated in Figures  1 and 2,  the Bureau is a relatively compact
and relatively mature agency by Washington standards.  The research
component of  the Bureau is  the largest element of  the  Bureau's
overall program,  with nine dedicated laboratories  located across
the country.

Almost half of the Bureau researchers are involved in research that
can be generally described as "metallurgical" in nature.  Research
on extractive processes—selective  capture of one or more elements
from host materials that are  either natural or recycled materials-
-represents a large component of this part of the Bureau's program.

About three years  ago,  the Bureau  began to explore  the matter of
the application of its metallurgical technologies to the problems
of  remediation of  contaminated Superfund sites,  both  minerals
production related sites and sites that had no direct association
with  minerals production.    This  lead  to the  execution  of  two
Memoranda of Understanding (MOU) with two organizational units of
EPA.    The  first  MOU  was  with  the  Office  of  Research  and
Development, Water Engineering Research  Laboratory, Cincinnati and
was signed in 1986.  The second, with the Office  of Solid Waste and
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Emergency Response, was signed mid-1987.
been the more active of the two.
This latter agreement has
On the basis of past experience, it would probably be best to try
to  deal  now  with  a  "conceptual  problem"  associated  with  the
Bureau's  techniques.   When we talk about metallurgical treatment
processes in the sense of our treatability studies, we are talking
about a tool kit of  approaches rather than a "black box"  in the way
that many in the EPA community use the term "process".  In addition
to the hydrometallurgical approach (and all of its variants) that
is the subject  of this discussion,  there are other metallurgical
approaches, e.g. beneficiation,  thermal, etc., that can be employed
alone or  in combination.  There are  dozens,  perhaps  hundreds of
permutations of arrangements of  these  tools of  metallurgy that
might be  employed  to  treat contaminated soils.   Some  are more
costly than others.   Some are more effective than others.  On all
of the treatability studies we have worked on to date,  there have
been a  handful  of  better  approaches, from which  the  Bureau has
picked "a process."  This  process  might  or might  not  be the best
process for a similar site down the road.

While it  might  be possible to field  a "universal  battery breaker
site decontamination machine", for example,  we have not set out to
develop such an  device.   Part of the reason is institutional—it
appears  that the Superfund  system  approaches each  site  as an
independent activity and no Project  Manager  can  look  beyond the
boundaries of his or her particular  project.   Part of  the reason
is   technical—what  appear   to  be  small   changes   in   site
characteristics  might  possibly  have a  major impact  on process
performance.  On  the other hand,  while we have not yet attempted
to develop these  generic treatment systems, there are a number of
things  that would  suggest  the idea  is worth  exploring.    For
example, our cost studies have shown that  unlike the situation with
mineral   processing operations,   Superfund  site  metallurgical
treatment costs are  dominated by the cost of equipment.  This would
suggest that a)  it would be in EPA's  interests to employ the same
basic treatment equipment at a large  number of sites,  and b) that
it  is  not  as  critical  that reagent quantities  be selected to
minimize  reagent  costs—some  "overkill"  can be  tolerated as long
as the equipment train has the flexibility to allow adjustment for
site-specific conditions.

Even at the most  simplified level  of generalization,  some of the
possible  hydrometallurgical  variation?  should be  obvious  from a
review of Figure  3.   The range of possibilities is not a weakness
of the metallurgical approach but  rather the basis of  its power.
It is somewhat  analogous to the situation with  software for your
PC.  The more powerful and full-featured the software,  the harder
it is to learn.   While  the beginner may be initially thrilled with
software that holds  his or her hand,  pretty  soon all the menus and
questions begin to get in the way and the user longs for a way to
directly address  the problem of interest.  The levels of residual
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contamination that EPA  seeks  are very low.  You  need a powerful
set of tools  to  meet the requirements.  The Bureau,  through its
research facilities,  can provide the needed tools.

Most of the balance  of  the discussion will deal  with the middle
portion of Figure 3.   However, there is a step that does not even
appear on that drawing  that warrants  a brief mention.  That step
is proper characterization of the material to be treated.

Characterization  in  the sense  we use  the  term,  relates  to the
determination, insofar  as is  possible,  of  the  nature and form of
the contaminants and the host material.  In what form of compound
or compounds are the contaminants present?  What is the nature of
the  host  material?     Are  there  other  (possibly  interfering)
materials present?   Most Superfund  sites are  contaminated with
products created by man and this is  another factor that prevents
the cook book application of  commercial metallurgical techniques
directly to the treatment of these wastes.

A few examples might help to demonstrate the  kinds  of treatment
techniques under  investigation.   The first two are  from ongoing
studies from  our base  program  of contamination  associated with
mining sites.   Coincidentally, both involve arsenic contamination
and arsenic is one of the elements that appears frequently on NPL
list of contaminants.   The  last is directly related  to our work
with EPA on Superfund sites.

Many minerals  production related solid wastes such as tailings and
flue dusts  are  not  too different  from soils  in terms  of such
characteristics  as mineral make-up, particle size, and response to
cleaning  technology.    In  fact,  some of  the  largest  tailing
contamination  problems  in  this  country  involve  deposition  of
tailings  along  stream  banks and at  the  bottom of lakes  and
reservoirs—sedimentation that  results in  a  mixture  of  mineral
wastes and natural soils.    A prime example of  this mixing is the
stream bank contamination along Silver Bow Creek in Montana.  These
tailings are open to  air and water erosion and  thus contribute to
arsenic contamination in Silver  Bow Creek  downstream from Butte,
MT.

Analyses of these tailings show an average arsenic content of about
500  ppm.  Mineralogical examination of  these tailings determined
that  the  material   is  mostly  quartz  with  lesser  amounts  of
K-feldspar and  plagioclase.   Minerals heavier  than quartz  and
feldspar make  up approximately 0.1 pet' of the tailings and consist
mostly of sphalerite  with  lesser amounts of galena,  chalcopyrite,
pyrite,  barite,  wolframite,  and  zircon.   Arsenic was  present as a
copper-arsenic sulfide,  either enargite or tennantite, and in much
smaller quantities as various sulpho-salts together  with  copper,
zinc,  vanadium,  and  bismuth.   Particle size of the bulk  of  as-
collected tailings was determined to be between 28 and 100 mesh by
screen analysis.

-------
-------
   tests  and   the  characterization  had  to  proceed  in  parallel.
   Initially  the   Bureau  Researchers  hypothesized  that  the  lead
   occurred as surface contamination  and  attempted  to scrub  the
   material  in  an   agitated  water  wash   to   no  avail.     The
   characterization work on the casing material revealed that the lead
   contamination,   in  the  form  of   lead   compounds   (principally
   sulfates),  occurred as crack filling materials.  Knowing the nature
   of the  problem, the Bureau researchers at the Rolla Research Center
   then crushed the casing material to -3/8"  and  washed  the product
   in water.   The processed casing material,  which  has a fuel value
   of 12,000-13,000 Btu/Lb now shows EP Tox results of less than 1 and
   total lead  levels  of less than 100 ppm.  This left the  sludge from
   the crushing/washing of  the casings  and the contaminated soil.

   EPA specified that the Bureau was to  try  EOTA, a chelating agent
   with which  EPA had prior experience,  as one of the  leachants,  in
   addition to two others of the Bureau's choice.   EDTA  exhibited a
   strong affinity  for  lead  as would  be expected.   However,  the
   problems  associated  with   the   solid/liquid   separation,   the
   difficulties in recycling the EDTA,  and a  number  of  other factors
   caused the  Bureau  to recommend against its use.  The Bureau tried
   an number of leachants and settled  on fluosilicic acid,  a waste
   product from the production of phosphate.
uo
v£> Initial tests  showed  that  a carbonation  step,  followed  by  the
   fluosilicic acid  leach  significantly reduced the  lead  levels.
   However the  Bureau was  initially unsuccessful in meeting EPA's
   goals of 5  and  500  for EP Tox and total lead.   When the results of
   the characterization studies became available, they showed that the
   soil contained  significant  amounts of metallic lead in  addition to
   the lead compounds that the fluosilicic acid could effectively deal
   with.   THe  answer  was to  add a  small amount (less than  0.5%)  of
   nitric acid  to  the final  rinse.    The  lab scale  tests are  now
   consistently producing results of less than 5 and  less than 500 ppm
   for EP Tox  and  total lead.

   The Region has recently signed a modification to the IAG which will
   result  in   the  scaleup  of  the  tests,  the   integration  and
   optimization of the process,  and  the design by  the Bureau of  a
   pilot plant  for field tests.  At present, the Bureau is  envisioning
   a trailer-mounted  plant  for the full  scale remediation  along  the
   lines shown on  Figure 4.

   The base Bureau research  program includes  technologic  development
   efforts which, while not funded by EPA or presently associated with
   any Superfund activity,  would seem  to have applicability  to  the
   kinds of Superfund  cleanup problems we have seen.   Two  examples  of
   this are  the  work in  column cells/fine bubble  flotation  and
   biotreatment to remove metals.

   From past discussions with  the  Regions and the  agenda  for  this
   meeting,  it is  apparent that EPA is  interested  in the  potential
m
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-------
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benefits of beneficiation.   There  have been a number  of  studies
and trials of techniques and devices to separate  the  fraction of
concern—the highly contaminated material—from the uncontaminated
balance of the soil.  If one could do this, at least the "reduction
of volume" part  of  SARA would be satisfied.  There are a number of
proven commercial products available like jigs, cyclones  and air
classifiers that  are used  for such  a purpose  in the  minerals
industry.  He have  routinely  included tests of these approaches as
part of our EPA treatability studies.   (To date however,  we have
not encountered  a contaminated material that broke down neatly into
contaminated and uncontaminated fractions.)

There are a number of more sophisticated approaches that may have
promise as part of  treatment processes  for Superfund  sites.   One
such approach on which the Bureau  has  done a  considerable amount
of research and which is in growing use by the minerals industry
involves fine bubble column flotation as shown in  Figure  5.   The
critical parameters governing the success of this approach are the
size  of  the  particles,   the   selection of  reagents  and  the
establishment operating parameters such that the  probability of
capture of the particles of interest are maximized.  The benefits
are improved  "graden/yield and reduced capital costs  compared to
conventional flotation cells.

Another relatively new technique is the use of bacteria to treat
metal contaminated solids.  The "newness" really refers to the use
of  biotreatment,   under controlled  conditions,   as  part  of  a
metallurgical treatment process—nature has employed this approach
for millions of  years.  As shown in  Figure 6,  these mechanisms have
been and are  being employed  in the minerals industry  on  a daily
basis  as  part  of  leaching  operations,  for  example,  for  the
production of copper.   (This  same basic mechanism,  operating on an
uncontrolled  basis,  is  responsible for  acid  drainage  from  coal
mines.)  The  Bureau's research program  is seeking  to  develop and
engineer systems that can be used in the field to selectively treat
contaminated wastes—both solids and liquids.

We are currently investigating several biotreatment techniques for
the mixed tailings-soils along the  arsenic contaminated waterways
referred to earlier.   Our researchers have  found  bacteria which
seem to absorb arsenic  from solution; tests are being conducted to
quantify this absorption and to determine the  mechanism by which
the absorption occurs.   Other bacteria may aid in leaching arsenic
directly  from  contaminated  soils.  . There   is evidence  in  the
literature that Thiobacillus  ferro-oxi'dans is capable of oxidizing
sulfides of arsenic.  A system of  injection and collection wells
along  the  streams  and creeks may  be successful  in  biologically
removing arsenic from the sedimented tailings and  soils.

In  summary,  the   Bureau  has  found  that   its   experience  in
metallurgical technology  has allowed  it to  successfully  treat
inorganic wastes from both listed  and unlisted sites.   We believe
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that these techniques can be applied to a wide range on inorganic
treatment  needs at  costs  which  are  lower  than,   or  at  least
competitive with, the alternatives.  We are continuing to work with
EPA and other Agencies to demonstrate  the applicability  of these
somewhat arcane technologies to Superfund problems.  ' We  are very
interested  in   further  cooperation,  including  work on  problems
related to the  area of mixed organic-inorganic contamination which
we understand is a particular problem for EPA and others.
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142
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                                                     Program Number:   87-20.5
               Innovative Electromembrane Process  for Recovery
                       of Lead from Contaminated Soils
               E. Radha KMshnan. P.E.. and William F.  Kemner
                            PEI Associates, Inc.
                              Cincinnati, Ohio
INTRODUCTION

     Numerous sites throughout the United States are contaminated with toxic
metals.  Battery reclamation, lead smelting and lead-based  paint  manufactur-
ing are examples of processes which could result in lead contaminated  soils.
Soils from defunct battery reclamation sites have been  found  to average about
5 weight percent of lead (Pb).  Quantities of contaminated  soils  range from
less than 5,000 cubic yards per site to almost 100,000  cubic  yards.  Many of
the sites are located over key underground aquifers 1n  populated  areas,
raising concerns for contamination of water supplies.  The  concentration
range of lead in soils found at 436 contaminated sites  has  been reported to
be 0.16 to 466,000 ppm, compared with the natural background  level of  2 to
200 ppm.1

     The cleanup of such sites has traditionally involved excavation of the
wastes and contaminated soils with subsequent disposal  at an  off-site, RCRA-
approved landfill.  In addition to increasing costs and dangers to public
safety from large-scale transportation of wastes, long-term environmental
liability 1s also a concern associated with the landfilling approach.   Many
experts have characterized this approach as simply "moving  the problem"
instead of solving 1t.  Thus, there Is great incentive  for  the development of
alternative methods for cleanup of contaminated sites.

     Figure 1 summarizes the alternatives available for treating  lead-contam-
inated soil.  It should be noted that only the soil-washing option actually
removes the lead from the contaminated soil.  This paper describes research
conducted to Investigate the process characteristics, design, and economics
of a soil-washing process employing an electromembrane  reactor (EHR) for
treatment of contaminated soils for recovery of heavy metals  such as lead.
Figure 2 provides a highly-simplified overview of the soil-washing process.
The process uses ethylenedlamlnetetraacetlc acid (EOTA) as  the chelating
agent and recovers lead by electrodeposltlon.  The primary  objective of the
research was to optimize, via bench-scale tests, the process  variables for
the cheUtion and electroplating (EMR) operations of the process.  The clas-
sification and dewaterlng steps, though crucial to the  overall process,
represent existing technology and were not studied specifically during this
research.  This process results in a lead product containing  about 90  weight
percent lead at optimum process conditions.

     The applicability of the process 1s highly site-dependent.  Factors such
as soil fines content, clay content, and lead solubility can  strongly  Influ-
ence the cost and performance of the process.  Consequently,  both the  soil
treatablllty (chelation) and electroplating tests were  conducted  on a  variety
of samples 1n order to make preliminary assessments of  process applicability.
CO
NTAHIMATID
MATtMIAl
CIMTMlt]
no
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Figure  1.    Treatment alternatives for lead-contaminated soils.
-------

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                                                       SOIL  TREATABIL1TY TESTS

                                                            The  purpose of the soil treatabl11ty testing was to determine the opti-
                                                       mum conditions  for soll-EDTA reactions to 1) maximize lead chelatlon. 2) mini-
                                                       mize  EDTA consumption, and 3) minimize reaction time.

                                                            A soil  treatabllity  test procedure was developed to evaluate the effect
                                                       of pH, EDTA  consumption,  and reaction time at a constant temperature.  The
                                                       treatabllity testing  involved physical and chemical characterization of the
                                                       raw material followed by  chelation testing for lead recovery/metals Interfer-
                                                       ence.

                                                       Physical  and Chemical Characterization

                                                            Soil  samples typically consist of varying amounts of gravel, sand, silt,
                                                       clay, and organic matter.  A sieve analysis was used to determine the distri-
                                                       bution of particle sizes  in the soil.  The exact test is described under ASTM
                                                       Designation  D 422.  Material passing a No. 200 sieve tends to be composed
                                                       largely of clays and  silts, and is generally difficult to dewater.  Screening
                                                       of the material prior to  reaction separates the material into fractions which
                                                       can be analyzed to determine the particle size distribution of the material.
                                                       Screening has shown a tendency for higher lead content material to segregate
                                                       in the fine  fractions.  Consequently, screening may be used to reduce the
                                                       volume of material to be  treated.

                                                            Samples of soil  from two sites were screened and extraction procedure
                                                       (EP)  toxicity tests performed on each fraction to determine if a toxicity
                                                       gradient  existed based on physical sizing.  The results shown 1n Tables I and
                                                       II Illustrate the tendency for lead to segregate in the fine fractions for
                                                       these soils. A similar relationship, however, may not be expected for all
                                                       soils.

                                                       Chelatlon Testing

                                                            Before  describing the chelation tests in detail, it 1s helpful to review
                                                       briefly the  properties and characteristics of EDTA.  There are many forms of
                                                       EDTA.  In this  work,  the  tetrasodium salt of EDTA was used as the chelating
                                                       agent.  By definition, a  chelating agent 1s a compound containing donor atoms
                                                       that  can  combine by coordinate bonding with a single metal atom to form a
                                                       cyclic structure called a chelation compound or, simply, a chelate.

                                                            A range of molar ratios of EDTA/lead were used at a selected pH  condi-
                                                       tion  to determine  the minimum ratio necessary for essentially complete chela-
                                                       tlon.  Liquid chelate was sampled from the soil-EDTA reactor at specified
                                                       time  intervals  to  determine chelatlon as a function of time.

                                                            These tests  provide  Information on  lead  recovery,  iron  Interference,
                                                       reagent needs,  and  feasibility of treating a particular waste by chelatlon.
                                                       The  ranges for pH,  time,  and EDTA use can be varied depending on the  partic-
                                                       ular soil.
-------
    Table I.   Sieve  analysis of waste from an Industrial site
SUe fraction
+20 mesh
(-20J+35 mesh
(-35)+100 mesh
(-100J+200 mesh
-200 nesh
In
Range
45-63
9-12
18-29
5-8
5
Percent
size fraction
Mean
54
11
23
7
5
EP toxlclty
value for Pb, mg/llter
67
186
174
248
344
Table II.  Sieve analysis  of  soil  from a battery reclamation site
Sire fraction
>10 mesh
>20 mesh
>35 mesh
>70 mesh
7100 mesh
>200 mesh
<200 mesh
Total Pb,
X
1.5
3.0
4.4
4.8
4.5
6.0
6.2
EP toxlclty
value for Pb,
mg/Hter
7
22
37
42
51
49
55
     The soil treatablllty procedures developed for this  study were  performed
on lead-contaminated soil samples from two Superfund sites  (Arcanum  near
Troy, Ohio, and Lee's Farm 1n Uoodvllle. Wisconsin).'  Table III  provides the
analysis of the metals content of these two soils.  Figure  3 Illustrates  the
relationship of chelatlon efficiency versus time for two  test runs on  the
Lee's Farm soil and one test run on the Arcanum soil.  It Is apparent  that
the chelatlon reaction 1s essentially complete within one hour  for both the
Lee's Farm soil and Arcanum soils at each of the EDTA/Pb  molar ratios.  It
cannot be predicted that other wastes or soils will necessarily be chelated
so rapidly.  Figure 4 presents final chelatlon efficiency as a  function of
EOTA/Pb molar ratio.  The optimum EOTA/Pb molar ratio appears to be  approxi-
mately 1.5 to 2.0 for both the soils tested.  The optimum EDTA/Pb ratio may
be different for other materials.  Chelatlon efficiencies exceeding  90 per-
cent were observed for the Lee's Farm soil at an EDTA/Pb  ratio  above 1.5.
The apparent lower chelatlon efficiency for the Arcanum soil may be  due to
the presence of either metallic lead (as opposed to Ionic lead)  1n the sam-
ple, or mlcroencapsulatlon of lead.

                 Table III.  Chemical analysis of test soils
                         (ug/g on as-received basis)
Element
Cadmium
Calcium
Chromium
Iron
Lead
Z1nc

Arcanum
4
59630
19
20790
78950
110
Soil source
Lee's Farm
1
47340
14
22010
38670
81
                                                                                                 Metallic lead Is  digested  In  the  analysis procedure for total  lead but
                                                                                            is not chelatable.  It should also be  noted  that metallic lead Is not
                                                                                            extracted In the EP toxlclty procedure used  to determine leachablllty charac-
                                                                                            teristics.  The EP test 1s  conducted at a  pH of 5 using acetic acid.   Since
                                                                                            the basic purpose of the chelatlon process Is to render the soil  nonhaiard-
                                                                                            ous, lead recoveries must be based on  the  ability of the chelatlon  process  to
                                                                                            produce a residue that has  an EP toxlclty  lead content of less than 5 mg/
                                                                                            liter (the federally allowable  standard) rather than the total lead removal.
                                                                                            EUR TESTS

                                                                                                 Previous research on the electromembrane reactor (EHRi has been per-
                                                                                            formed In the context of regenerating Ion-exchange resins.    The current
                                                                                            research expanded upon this  application.   Several  variables are of Importance
                                                                                            1n the experimental  design of the EHR tests.
-------
   1001
    90-1
u
Z
IU


g  e

<

ui  50-
x
U

A  401
    30
                                       pH: 12.3-12.6
                                       pH:11.8-12.3
pH:11.3-12.3
                 246

                      REACTION TIME, hrs
                   10
LEGEND

•  3.68 EDTA/Pb. LEE'S FARM SOIL

A  0.92 EDTA/Pb. LEE'S FARM SOIL

*  0.43 EDTA/Pb. ARCANUM SOI
                       Figure  3.    CheUtion efficiency as a  function of time.
 U

 UI
 o
 £Z
 u.
 ui
 ui

 U

 A
 Q.
                         LESEM2

                          •  LEE'S FARM SOIL

                          *  ARCANUM SOIL
        01234567


                      EDTA/Pb  MOLAR  RATIO



       Figure 4.    Chelatlon efficiency as a function of EOTA/Pb molar ratio.
-------
Electrode Potential—The extent of chemical  reaction occurring In an electro-
lytlc cell is directly proportional to the quantity of electricity passed
Into the cell.  For example, 1t requires 2 moles  of electrons to produce a
mole of coppjr from Cu*  and 3 moles of electrons to produce a mole of alumi-
num from Al' :
     Cu»  + 2e'

     Al'* + 3e~
Cu

Al
The electrical charge on a mole of electrons  Is  called a Faraday (F), equiva-
lent to 96.500 coulombs.  A coulomb 1s  the  quantity of electrical charge
passing a point In a circuit 1n 1  sec when  the current 1s 1 ampere.  There-
fore, the number of coulombs passing through  a cell can be obtained by multi-
plying the amperage and the elapsed time  In seconds:


Current Density—Current density Is calculated as mil If amps (ma)/cm  (amps/ft*.
etc.).Current density for the experiments was  determined by computing the
ratio of the current flow on the power  supply unit to the cross-sectional
area of the membrane.


£H—The pH 1n the electromembrane  reactor Is  a very Important process condi-
tion which Influences both the removal  of metal  from the solution and the
recovery of the chelatlng agent by regeneration.  The pH at the anode and the
cathode varied during the EHR experiments due to the production of hydrogen
Ions at the anode and hydroxide ions at the cathode; the pH, however, was not
adjusted during each experiment.


Current Efficiency—The energy requirement  for Ionic transport 1n the electro-
membrane process Is a function of  the electrical resistance of the solutions
and the membranes and the back electromotive  forces caused by concentration
gradients.  The current efficiency can  be calculated according to the follow-
ing equation:

                     Metal ion removed  (meg)  x 96.5 (C/meq)
Current efficiency
     where
                        T1me(s)  x  applied  current  (C/s)
                                                           x 100S
             meq • mi 1Hequivalent
               C • coulomb
               s • second

     The current efficiency was determined as  a  function of time for the
tests.
Chelate Concentration—The concentration  of  the  lead  chelate in the cathode
chamber of the EHR affects current efficiency.   As  concentration decreases,
power requirements to plate a given mass  of  lead Increase.
Experimental Procedure

     Figure 5 depicts the reactor system used for these experiments.  The
rectangular unit was constructed from a commercial glass aquarium with 1/4-
inch-thlck plexiglass.  It was divided into two chambers by two 1/8-inch-
thlck plexiglass pieces.  The frames served as supports for the cation
exchange membrane.  The membrane was glued Into place and the joints sealed
with sllicone rubber sealant to prevent leakage between chambers.

     The membrane used was manufactured by Ionics, specifically 61CZL386
modacryllc fiber-backed cation transfer membrane.  The membrane has low
electrical resistance and excellent resistance to physical and chemical
stress.  Host Importantly, 1t has the ability to allow sodium Ions to pass
from the anode to the cathode chamber while preventing ionic transport 1n the
opposite direction.

     Lead electrodes were used In the EHR system.  Both electrodes had dimen-
sions of approximately 7 by 10 by 1/16 inch.   They were mounted on wooden
dowel rods suspended across the top of the aquarium.  The power source sup-
plied a potential of up to 40 volts and a direct current of up to 30 amps.

     Once the reactor was operational, each run was started by addition of a
5 percent by weight of sodium carbonate solution to the anode chamber.  In
addition, an appropriate amount of metal chelate complex solution was placed
in the cathode chamber.  Each electrode was then placed In the EHR by sus-
pending it approximately 1 Inch from the membrane surfaces.  The test began
when voltage was applied and the current set at the proper amperage.  The
voltage across the circuit was allowed to vary In such a fashion that the
current was maintained at a desired setting.

     Considering the overall reactions involved In the reactor system, the
major reaction of concern was the one resulting 1n removal of metal from so-
lution; thus, the metal concentration and reaction time were monitored regu-
larly.  This was done by taking samples from the cathode chamber at regular
time Intervals.  To enhance mass transfer, a magnetic stlrrer was placed in
both chambers to cause mild turbulence throughout the operational period.

Experimental Design

     The three primary control variables of Interest in the EHR bench-scale
experiments were current density, lead concentration 1n the chelate. and
cathode solution pH.  Higher current density generally produces a lower qual-
ity plated metal, but plated metal quality Is not of paramount Importance in
the soil-washing process as long as Us quality Is not so  inferior  that it
would Inhibit sale of the product. .The maximum current density for the
experiments was kept below 30 ma/on .  Effective operation at both  high and
low lead concentrations is extremely Important in order to accommodate various
levels of contamination In soil or waste materials.  Solution pH is of
Interest because of the need to elevate pH to Inhibit Iron chelatlon in high
Iron wastes.  The EHR should thus be able to function well at both  low and
high pH.
-------
                   ANODE (•)
CATHODE (•)
Oo
                                 CASKET•
                                      N»*
                         •LEAD ANODE
                                 COVER
                                 PLATE '
                      MAGNETIC ST1RRER
                                                    Pb-EDTA SOLUTION
                                                      .OH"
                                                    LEAD CATHODE
                                                              «,**_
                                                         MAGNETIC 8TIHRER
                                                            C       ")
                                                                                    12 In.
     The source of lead chelate solution for the  experiments was  actual
chelate produced at the Lee's Farm site.  This  material  contained about  3
percent Pb and portions were diluted with water to create nominal 1  percent
and 0.2 percent solutions.  The solutions were  adjusted  to the desired pH
using sulfurlc add or sodium hydroxide.  Table IV summarizes  the actual  lead
content and pH of the feedstock solutions.

Table IV.  Lead content and pH of feedstock solutions used in  EMR experiments
Feedstock
No.
1
2
3
4
5
6
7
8
Nominal lead
content, mg/llter
30.000
30.000
10.000
10.000
10.000
3.000
2.000
2.000
pH
11
4
11
8
4
11
8
4
                                                Five experiments were performed on  the 0.2 percent  Pb solution, and two
                                           experiments  each  were performed  on  the  1  percent and  3 percent Pb solutions.
                                           A partial factorial  experimental  design was adopted to evaluate the effects
                                           of lead concentration,  current density,  and pH.

                                                Theoretical  plating  time was calculated based on Faraday's law.

                                                                       Pb* + 2e"  •» Pb

                                                Two moles of electrons (2 faradays)  are required to plate 1 mole  (2
                                           equivalents) of lead.   The grams of lead  plated 1n  1  hour at  1 ampere  at 100
                                           percent  current  efficiency can  be  calculated  as follows:
                                           grams of Pb  • (1  hr) (1 amp) (3600  sec)  (1 coulomb)   (1 faraday)    (1 mol  Pb)
                                                                                                                                                        amp-sec    96.500 coulomb   2  faradays
                                                                                                                    • 3.86 9 Pb/amp-hr
                                       1/4 In.  . U.J 1/4 In.
                             2 in.
                       Figure 5.    Schematic  Illustration of EMR test unit.
                                                Given the total amount of Pb 1n solution. and the desired  current den-
                                           sity. theoretical plating time (at 100 percent current efficiency)  was deter-
                                           mined.  Current densities were calculated based on the 400 cm2 area of the
                                           membrane.

                                           EMR Test Results

                                                Figures 6 through 9 Illustrate plating efficiency (I.e..  lead  plated as
                                           a percent of total lead In solution) as a function of time. As expected.
-------
       so
       JO
                      05            10

                      PL»THOTllE.ht»
                                               I.S
   IfflfHD
   A pH1ICURR9

      1FGENO

      T pH a CURRENT OEMSTTY IS imtai?
Figure 7.  Lead plating efficiency as a func-
tion of tine (0.2 percent Pb in initial solu-
tion, pH ° 4, 8).
>

c
     100
      80
      60
      40-
      20-
                 pH 11 CURRENT DENSITY 15 matem2
                 pH 11 CURRENT OENSrTY 25 maton2
        •0.0        0.5         1.0        1.5        2.0        2.5

                             PLATING TIME, hra

       Figure 8.  Lead plating efficiency as a  function of time (1 percent Pb in initial solution).
                                                                119
-------
                                                LEAD REMOVAL,*


                                            8       S       8       8
8
Ul
O
                          ey
                          3'
                          =T
                             Increased lead Is plated with Increasing time 1n all cases.  Extremely high
                             lead recoveries and current efficiencies are observed for the 3 percent and  1
                             percent lead solutions during the experimental time period.  It appears, how-
                             ever, that current efficiency (and subsequent lead removal) at the starting
                             lead concentration of 0.2 percent 1s low regardless of pH or current density
                             Figures 6 and 7 show that lead recoveries are below 40 percent at the 0 2
                             percent lead level for the experimental time period.  Greater time periods
                             should result In higher lead removal efficiencies for the low lead solutions.
                             Figures 8 and 9, however, show lead removal  efficiencies approaching 90
                             percent for the 1 percent and 3 percent lead solutions.  Figure 8 shows the
                             effect of current density at constant pH for a 1 percent lead solution.  As
                             expected, the  higher current density produces a faster plating rate.  It
                             should also be noted that higher current density produces a spongy lead
                             deposit on the electrode.  Figure 9 Illustrates the high plating efficiency
                             achievable at higher Initial lead concentrations.  The effect of current
                             density on plating rate 1s again confirmed by the results shown In Figure 9
                             There is no apparent effect of Initial  cathode solution pH on platlnq effi-
                             ciency.

                                  There was no noticeable difference in the visual  appearance of the lead
                             product from the various experiments of a given Initial lead concentration.
                             In the 0.2 percent lead experiments, the plated lead was not visibly discern-
                             ible on the electrode, but was confirmed by  analytical  results and the increase
                             1n the weight of the cathode.

                                  Based on the experiments  on the 0.2 percent lead liquor, the current ef-
                             ficiencies are higher at lower current  densities, decreasing from 40 percent
                             at a current density of 5 ma/cnr to approximately 20 percent at 25 ma/cmZ
                             There 1s no apparent effect of pH on this relationship.  In the full-scale
                             process, the current efficiency should  not be a controlling factor in the
                             economics because power costs  are Insignificant compared to other cost ele-
                             ments.  Time, however, 1s an Important  factor because it relates to labor
                             cost.  Consequently 1t 1s desirable to  run as high a current density as
                             possible.

                                  Table V provides an analysis of the plated lead product for those ex-
                             periments where sufficient deposit could be  scraped off the cathode.  The
                             plated metal analyzed over 75  weight percent lead 1n Runs 1 and 2.  As shown,
                             the amount of other metals plated 1s Insignificant compared to the lead.
                             Although not shown, the moisture content of  the product 1s the other main
                             constHutent.  After drying, therefore,  the  lead product 1s expected to have
                             a purity in excess of 90 percent.

                                  Hydrogen Is generated at  the cathode as a product  of the electrolysis of
                             water.  The hydrogen generation rate was not measured,  but the pH Increase
                             detected during the experiments 1n the  cathode chamber  Indicated a decrease
                             in hydrogen Ion concentration.
-------
Table V.  Analysis of plated metal from EHR experiments
              (all ug/g as-received basis)
Experiment
No.
Cd
Ca
Cr
Cu
Fe
Pb
. Hg
Zn
1
6.7
1128
<1.2
264
35.1
787700
74.1
54.0
2
3.1
1751
<1.2
226
25.7
755700
292
43.1
8
4.0
499
<1.2
175
23.9
497500
70.2
56.8
9
2.1
2709
<1.2
265
48.7
669500
180
75.8
9
(duplicate)
2.4
3015
<1.2
259
51.2
672000
182
84.7
SCALE-UP

     Although this research focused on the chelation and plating steps  of the
soil-washing process, the design factors necessary for scale-up must be
considered for the overall process.  The four major process operations  are
solids handling, EDTA reaction/washing, lead plating (EMR), and water treat-
ment.

Solids Handling

     Initial solids processing depends upon the specific site characteris-
tics.  The material may be processed via screening, magnetic separation,
and/or crushing.  Metal and other bulk material must be removed.  If crushing
is required, the material may be rescreened and stockpiled for later feed to
the system.

EOTA Reaction/Washing

     The purpose of the EDTA-reaction step Is to thoroughly mix the soil and
EDTA solution to chelate the lead.  After chelation, the lead complex is
washed from the solids in a series of dilution steps.

     The major parameters governing the operation of this phase are the lead
concentration leaving the system as a final product and the moisture content
of the solids as they move through the system.  Dewaterlng characteristics of
the material are critical In this step.  The amount of water to be used must
be optimized through the use of multiple stages.

Water Treatment

     Water from the plating step is sent to a waste treatment system.  When
the lead concentration decreases to a low level in the EKR, it will probably
be cost-effective to reconcentrate the water to maximize lead recovery.
Eventually, dissolved solids will build up and a blowdown stream will have to
go to a waste treatment system.  It 1s essential to the economics of the
process to recover and reuse the chelating agent prior to final discharge of
the water.
                                                                                           ECONOMIC  ANALYSIS

                                                                                                Comparative economics for cleanup of a given site are highly dependent
                                                                                           upon site location,  lead concentration, and nature of the material.  Some
                                                                                           sites contain  lead only, and others are contaminated with multiple pollu-
                                                                                           tants, both  inorganic and organic.  In addition, the dewaterlng characteris-
                                                                                           tics of various materials vary widely, which in turn affects processing cost.
                                                                                           The  comparative economics of soil washing versus other alternatives must be
                                                                                           determined specifically and individually for each site.

                                                                                                A computerized  cost model was developed to evaluate the effect of site-
                                                                                           specific  process variables.  Table VI lists the variables Included 1n the
                                                                                           model. The  current  cost model is based on the use of mobile equipment, in-
-------
                     TABLE VI.   Variables  in cost model
Total Material  (cubic yards)
% Material Dry  Process
Equipment Rental, S/mo.
  Mixers
  Screens and conveyors
  Filters
  EMR's
  Tankage
  Onsite Trailer
  Others
Operation, hr/day
Number of Rinses
Water/Soil Ratio.
Filtering Rate, gph/sq.  ft.
Plating Rate, hr/2000 gallons
Reaction Time,  hr/batch
Batch Size, yd1
Analytical, $/batch
Operating Supply, »
Maintenance Supply, X
Lead in Soil. 1
Lead Recovery,  t
EOTA/Lead Ratio
EDTA Recovery,  »
Capacity Utilization. I
Cost of EDTA. $/lb
Cost of Caustic, $/ton
Cost of Sulfurlc add, S/ton
Cost of Sodium Carbonate, S/ton
Cost of Sodium Sulflde.  S/ton
Lead Credit, S/lb
Slowdown rate,  1
Water Treatment. POTU,  S/1000 gal
Trans, to POTU. 
-------
REFERENCES

1.   R.  Sims, and K.  Wagner.   "In-sltu treatment techniques applicable to
     large quantities of hazardous waste contaminated soils," Proceedings of
     Management of Uncontrolled Hazardous Waste Sites. Hazardous Materials
     Control Research Institute (HHCRI). Silver Spring, MO.  Library of
     Congress. Catalog No.  83-82673.   (1983).

2.   Castle. C.. et.  al.  "Research and development of soil washing system
     for use at superfund sites," Proceedings  of Management of Uncontrolled
     Hazardous Waste  Sites. Hazardous Materials Control Research Institute
     (HHCRI). Silver  Spring.  MO.  Library of Congress, Catalog No.  81655.
     (1985).

3.   Tseng, Dy1-Hwa.   "Regeneration of heavy metal exhausted cation exchange
     resin with a recoverable chelatlng agent," A Thesis submitted  to the
     Faculty of Purdue University, Dr. James E. Etzel, School of Civil Engi-
     neering.  (Aug 1983).
-------
-------
               STUDENT PAPER COMPETITION

      To encourage student participation in the Association and to
   recognize outstanding research at New England colleges and
   universities,  NEWPCA recently held its fourth annual student
   paper competition. Judges under the direction of Mr. William
   VanBlarcom  reviewed a number of entries and selected four
   finalists who presented their papers at the January 28 session of
   the NEWPCA 1985 winter meeting. Based on the quality of the
   written papers  and  the  oral  presentations, judges  selected
   Camille C. Connick as winner  of the $200 cash award. Other
   finalists, each of whom received a $100 cash prize, were Robert C.
   Backman,  Northeastern University (The Treatment of Dairy
   Wastewater  by  the Anaerobic  Up-Flow Packed  Bed Reactor);
   AkbarJohari, University of Rhode Island (A Pilot Study of the
   Responses of Powered and Granular Activated Carbon in the
   Removal of  Shock  Loadings of Synthetic  Organics); and Bid
   Alkhatib,  University of Rhode Island (Treatment of a Combined
   Petrochemical Industrial Waste Stream for Reuse).

M    Presented herein is Ms. Connick's winning entry. Copies of
15 the other finalists1 papers are available from NEWPCA.

   MITIGATION OF HEAVY METAL MIGRATION IN SOIL

                    BY CAMILLE  C. CONNICK*

   INTRODUCTION

      The uncontrolled or accidental contamination of the environ-
   ment  with hazardous materials  through chemical  spills and
   hazardous waste site releases necessitated the enactment of the
   Comprehensive  Environmental  Response  Compensation  and
   Liability Act of 1980 (CERCLA) often called Superfund. The pur-
   pose of one Superfund  program, the U.S. Environmental Protec-
      •Graduate Student, Dept. of Civil Engineering,- Northeastern University.
   Boston, Massachusetts.
                       C.C. CONNICK

tion Agency's (USEPA) Chemical Countermeasures Program
(CCP). is to investigate in-situ chemical methods for mitigating or
eliminating environmental damage from releases of toxic  and
other hazardous materials to the soils around uncontrolled hazar-
dous waste disposal sites and from spills of hazardous chemicals
to still or relatively slow moving surface water bodies. Because it
is recognized  that the  environmental  impact  of  hazardous
material spills and releases can be worsened by adding chemicals
indiscriminately, the CCP is intended to provide guidance  and
define appropriate treatment techniques.
    This investigation of in-situ treatment of soils contaminated
by heavy metals was performed as a joint research project with
the USEPA and Northeastern University. The study involved
the determination of adsorption isotherms for the heavy metals
and specified soil, as well as the desorption behavior of the metal
using water  rinses, water and surfactant rinses, and  water plus
chelating agent rinses. The first phase consisted of shaker table
agitation (equilibration) to determine maximum  adsorption of
metal to soil. The second phase involved the use of soil column
studies  to evaluate the maximum adsorption/desorption of the
metal. A simulated spill of heavy metal-laden liquid for soil con-
tamination was followed by  successive treatment rinses under
gravity  flow conditions to determine removal efficiencies.  In-
fluent and effluent pH, metal content, permeability rates  and
variations, and chemical oxygen demand (COD) were monitored
during the study to determine metal removal efficiencies and the
occurrence of unanticipated reactions.
    The results of this research and results from a similar study
investigating the use of in-situ treatment of soil contaminated
with hazardous organic constituents are to be used as the basis
for development of pilot scale testing in a chemical additive treat-
ment tank at USEPA's Oil and Hazardous Materials Spills En-
vironmental Test Tank (OHMSETT) facility in Leonardo. NJ.

BACKGROUND INFORMATION & LITERATURE REVIEW
    The soil used in the chemical countermeasure  study  was
selected based on its frequency of occurrence at Superfund sites
in New Jersey and also its availability for excavation in an
-------
                       METAL MIGRATION IN SOIL
                                                                                              C.C. CONNICK
ON
uncontaminated condition. The soil selected for the research was
Typic Hapludult of the Freehold Series. It is described as fine to
coarse loamy, low clay content (< 15%) and a high content (>
15%) of fine, medium, and coarse sands, plus coarse fragments up
to three inches. Only soil from the B horizon was intended to be
used so as  to attempt to model soil containing contaminant
releases which  are greater than two feet underground.  Such
releases usually affect large volumes of soil, making excavation
and land treatment methods  and equipment uneconomical and
physically impractical

    The characteristics of soil have a tremendous effect on the ef-
ficiency of various treatment processes for contaminant removal.
Grain  size,  specific  gravity,  density  and water  content
characterizations determine available void volume, soil porosity,
and permeability which directly affect both pollutant and treat-
ment considerations.  Buffering capacity and soil pH  affect
neutralization and possibly precipitation reactions resulting in
enhanced or decreased water solubility of products. High organic
soils (such as peat) have a higher affinity for non-polar organics,
which  can  affect  in-situ  treatment with  surfactants and/or
solvents. A high  cation exchange capacity (CEC) observed in
some clays and fine silts can attenuate treatment of metals and
metal salts. A high mineral content can affect neutralization and
redox treatment of acid spills.  In some cases, treatment of a
caustic spill with acid might increase resolubilization of inherent
metal species.  Interfering reactions can result in a need  for a
greater volume of the treatment reagent, increasing wastewater
treatment requirements.

    A complete chemical and physical analysis of the soil was
performed prior to the start of the studies by  JRB Associates'.
The mineralogical composition of Clarksburg soil was determined
using X-ray defraction studies. Quartz is the  major phase,
representing at least  98  percent  of the total weight.  No
measurable  amounts of clay  minerals appeared in the sample
which accounts for the relatively low CEC of 8.6 mg  Na/100
grams. The organic carbon analysis showed only 0.12 percent.
                                                                             The average permeability when compacted to a density of 107
                                                                             Ibs/cu ft was 1.5 X 10~* cm/sec. The natural moisture content was
                                                                             10 to 12 percent.

                                                                             Metal Contaminants

                                                                                The heavy metals (Cd, Cu, Pb, Ni, Zn) selected for use in the
                                                                             reseach were chosen based on frequency of occurrence in soil at
                                                                             USEPA Region  II Superfund sites and concern for toxicity to
                                                                             human health and the environment. The metals Cd, Cu, Pb,  Ni
                                                                             and Zn were detected in soil at 4,3, 7,3 and 5 of 50 sites reviewed.
                                                                             respectively, at  concentrations ranging from  2,000 to 30,000
                                                                             ppm. The toxicity of these metals in such elevated concentrations
                                                                             is apparent when compared to the  acceptable concentrations
                                                                             specified by USEPA water quality criteria and the reported Rat
                                                                             Oral LDM of these cations (Table 1).

                                                                                Table 1.  WATER QUALITY AND TOXICITY LIMITS
           USEPA Water Quality
Metal           Criteria, ppm
Cd               0.01
Cu               1.
Pb               0.05
Ni               0.0134
Zn               5.
Rat Oral LDW
   mg/kg
   88 (CdCl.)
  265 (CuCl)

  105 (NiCL,)
  350 (ZnCl,)
                                                                             Chemical Countermeasures
                                                                                 A literature review was performed to investigate the avail-
                                                                             able methods for in-situ treatment of contaminants. Three types
                                                                             of treatment were reported for either removing or fixing con-
                                                                             taminants in soil including: use of surfactants to solubilize and
                                                                             flush contaminants; use of chemicals for in-situ metal precipita-
                                                                             tion; and use of chelating agents for metal extraction.
                                                                                 Surfactants were reported as being successful in the recovery
                                                                             of gasoline from soils  and as  having the  ability  to solubilize
                                                                             organic materials that were previously only solubilized in organic
-------
                 METAL MIGRATION IN SOIL

solvents'. Several analyses were performed by JRB Associates'
to determine the appropriate concentration of surfactant/water
solution which would provide adequate pollutant extraction effi-
ciency and yet not inhibit soil-column flow. A mixture of two non-
ionic surfactants, one percent Adsee 799 (Whitco Chemicals) and
one percent NP90 (Diamond Shamrock) in tap water was chosen
as the chemical countermeasure to  be tested for in-situ treat-
ment. Both  surfactants, Adsee 799 and NP90, are considered
non-toxic. They are often used for treating  farmland to enhance
percolation of fertilizers and irrigation waters.  The surfactants
are biodegradable and the potential for excessive accumulation or
hazardous effects is minimal, which further enhances their ap-
plicability for in-situ removal of organic contaminants. The high
organic content of the surfactant allows one to monitor its con-
centration in soil leachate by performing analyses such as the
COD determination of organic content.
  The use of sodium sulfide for in-situ metal precipitation and the
use of ethylenediaminetetracetic (EDTA), a chelating agent  for
metal extraction were reported as successful in fixing and remov-
ing heavy metal contaminants in soil. Chelating agents are com-
pounds or ligands (generally organic) that coordinate or bond a
metal ion in more than one position. This bonding of the metal
ion, in most cases results in its deactivation. The  metal  is no
longer able to react chemically and is, therefore, made less toxic*.
Competition from hydrogen ions usually occurs at low pH levels.
A decrease in pH always produces a shift towards disassociation
of the complex ion (an increase in free metal concentration).
Organic chelating agents may be divided  into two classes,  se-
questrants and precipitates. Sequestrants form chelate  com-
plexes which are soluble in water; therefore, the compound still
remains distributed throughout the water body although in a less
toxic form.
    EDTA is a sequestering agent used in metal cleaning, preser-
vation of canned fruits and  vegetables, leather tanning, and in
medical treatment of Zn, Fe, Ni, Pb, and Hg poisoning. EDTA is
generally applied as a soluble sodium salt along with a buffer
solution such as ammonia ammonium nitrate to maintain a pH of
                                                                                               C.C. CONNICK
9 to 10. Since the effectiveness of the chelating agent EDTA is
pH dependent, the buffer solution was prepared so as to maintain
a pH of 9 to 10 when subjected to the acidity of the soil system at
the time of treatment and during the displacement of hydrogen
ions as the EDTA reacted with the metal cations in  the  soil
system1. A 0.144 M  concentration of disodium  EDTA was
selected as the chemical countermeasure to  be  tested in this
research along with the prescribed surfactant combination sup-
plied by JRB Associates and  tap water1.

EXPERIMENTATION METHODS AND MATERIALS
    The laboratory study conducted to evaluate the effectiveness
of the chemical countermeasures  included shaker table agitation
and gravity flow  soil column studies. To insure data accuracy.
replicate leachate samples were  analyzed along with  blank
samples (non-contaminated soil mixed with deionized water) for
each run during  shaker table analysis and column tests.  All
glassware,  plastic ware, columns, storage vials, and  any in-
struments used in the study were acid cleaned (1 + 1 HNO,) and
rinsed  with deionized  water where feasible. Control samples of
metal contaminants were placed in shaker table bottles and a col-
umn to evalute the extent of  the cation adsorption onto the ex-
perimental  apparatus throughout the course of the study.
Shaker Table Studies
    Four different concentrations,  as shown  in Table  2, were
prepared for each  metal using a solution of the sulfide or acetate
salt of  the metal with deionized water. The selection of the metal

   Table 2.  METAL CONCENTRATIONS FOR SHAKER
                 TABLE ADSORPTION STUDY
Metal (Source Compound)
Cadmium (Sulfate)
Copper (Sulfate)
Lead (Acetate)
Nickel (Sulfate)
Zinc (Sulfate)
Concentrations, mg/l
40,000
2,000
20.000
20,000
30,000
4,000
200
2,000
2,000
3,000
400
20
200
200
300
40
2
20
20
30
-------
                 METAL MIGRATION IN SOIL

concentrations was based on the review of the data on average
contaminant concentrations found in, Superfund sites. The pur-
pose of various concentrations of the specified metals during the
adsorption  shaker analysis was to determine Freundlich and
Langmiur isotherms which allow determinations of compound-
specific soil/water partition coefficients.
    Seven pyrex bottles for each of the specified concentrations
of the five metals were agitated with 100 ml of the metal solution
and 10 grams of the soil. Agitation time ranged from 15 minutes
to 48 hours with samples removed at intervals of 15 min. 30 min,
1 hr, 3 hr, 6 hr, 12 hr, 24 hr and 48 hr for analysis. The shaker
table was operated at 180 rpm throughout the analysis to insure
complete mixing of the soil in the metal solution (Figure 1). pH
values of the initial metal solution prior to mixture with the soil
and pH of each liquid sample from the adsorption analysis were
     Figure 1.  SHAKER TABLE ADSORPTION STUDY
                       C.C. CONNICK

recorded. Samples removed at the specified times for each metal
and their respective concentrations were filtered using a Vacuum
Pump Millipore Filter Apparatus and a 0.45-micron filter pad
placed in a sample vial and acidified to a pH of 2 with 1 + 1 HNOj.

    Soil samples from the 48-hour  time interval for  each metal
and its respective concentrations were digested using the Nitric
Acid Digestion Procedure (Standard Methods, 302D, 15th Ed.)
The purpose of the digestion was  to  determine  the maximum
quantity adsorped on the soil following the longest contact
period. Metal content of each sample was determined using a
Perkin Elmer 560 Atomic Absorption  Spectrophotometer (AA).
Data from the adsorption analysis using the shaker table were
presented in the form of plots of percentage of contaminants in li-
quid samples versus time. These data were used to obtain the
adsorptive capacity of the soil at a given contaminant concentra-
tion. Plots of concentration adsorbed per unit weight versus
residual concentration were used to  obtain adsorption isotherms.
Soil Column Studies

   Column tests were conducted for each of the five metal con-
taminants and a mixture of Cd, Cu, Ni, and Zn to simulate field
contamination and cleanup using the specified chemical counter-
measures, under gravity flow conditions. The custom-fabricated
soil columns used in this study were 32-inch (81.28-cm) long clear
plexiglass cylinders with an inside diameter of 2.75 inches (6.985
cm). Both ends of the column were fitted with a  plexiglass cap
with  1-inch  (2.54-cm) diameter holes.  A 2.5-inch (6.35-cm)
diameter,  0.25-inch thick perforated plastic disk  was placed at
the base of each column to  prevent the loss of soil  during the
analysis. The caps were held in place with four nuts attached to
support rods running from column top to column bottom. Teflon
tubes connected to plastic fittings  threaded into the end  caps
allowed the introduction of aqueous solutions and the collection
of effluent samples. Tubes at the base of the columns were placed
into  one-liter plastic  containers for the collection  of  effluent
samples during column rinsing. An aqueous solution contaminant
or treatment rinse was introduced at the top of each column in
-------
                 MKTAL MIGRATION IN SOIL

premeasured aliquots in such a manner as to minimize the distur-
bance of the surface soil structure (Figure 2).
Column Packing
    A plug of soil weighing 0.73 pounds (331 grams) was brought
to the field moisture content of 11 to 12 percent and added to the
column. It was packed in 2-inch (5.1-cm) lifts using a custom-
made controlled-drop hammer compactor designed to  fit inside
the column (Figure 3.)
  This procedure was repeated for a total of nine lifts per column
to acheive a soil height of 18-inches (45.72-cm), a total volume of
106.9 cubic inches (1752.3 cc) and a total  mass of 6.6 pounds
(2979 grams). Records were maintained for each plug of soil that
was added to each column. Soil weight, packing depth, number of
taps required, and compaction data (from the  pocket penetro-
meter) were monitored for uniformity. The columns were packed
          Figure 2.  SOIL COLUMN APPARATUS
                       C.C. CoNNICK
 Figure 3.  CONTROLLED-DROP HAMMER COMPACTOR

in this manner to achieve the desired density of 105 to 110 Ibs/cf
(1.68 to 1.76 gm/cc) to simulate original field conditions and the
desired permeability rates of approximately 1.6 X 10"' to 1.0 X
10'» ft/sec (5 X 10"4 to 3 X 10'4 cm/sec).

Determination of Quantity of Countermeasure

    The treatment or cleanup of the contaminated soil was de-
fined  as  the  number  of pore volumes of water or  water and
countermeasure needed to remove the desired amount of metal.
Successful cleanup was defined as the removal of enough metal to
produce a leachate from the columns which fell below EP toxicity
criteria4.  EP Toxicity Concentrations for the heavy metals used
in this study are presented in Table 3. EP toxicity values are 100
times the concentration permitted by drinking water standards.

    The pore volume (quantity of water within the  pores of a
saturated soil sample) was calculated using the following equation:
                       pv = wv — sv
-------
                 METAL MIGRATION IN SOIL
where pv = pore volume (cc); wv = whole volume of soil in col-
umn (cc); and sv = solid volume of soil (cc) = (weight of soil added
to column in grams)/(specific gravity in g/cc)1.
    The determination of specific  gravity of  the  soil was
calculated following the procedure outlined in Methods of Soil
Analysis' and ASTM D854-58. The pore volume of each of the
packed columns was determined based on the above formula. The
average pore volume of the 14 packed columns was 690 ml and for
the remainder of the study this volume was used as the "treat*
ment" pore volume.

       Table 3.  EP TOXICITY CONCENTRATIONS
          Metal
          Cadmium
          Copper
          Lead
          Nickel
          Zinc

Column Contamination
Concentration, mg/l
        1
      100
        5
        1.34
      500
    The concentration  of contaminant  used  in the column
analysis was chosen as the maximum concentration used in
shaker table analysis. Two columns were contaminated with each
metal. Two columns packed with soil were used as blanks. No
metal was applied to these columns, but they did receive the
treatment rinses applied to the contaminated columns.
  Columns  1 to  10  received 1.915 liters of  the metal con-
taminants. The tube at the base of the columns was closed off and
the contaminant poured slowly into each column through the hole
in the cap of each column. The columns were filled to the top with
the metal solution which was allowed to saturate the soil for four
days. Following  this  period of saturation, the metal con-
taminants were drained from the base of each column into a two-
liter collection container. The columns were then allowed to air
dry for two days  to insure complete draining and simulate the
                        C.C» CONNICK

 drying of a spill which might occur in the field. Samples of the
 drained contaminants (leachate) were analyzed for metal concen-
 tration using the atomic adsorption spectrophotometer (AA). The
 pH of the metal contaminant was recorded before and following
 its passage through the soil column. A soil sample was taken
 from the surface of each column and digested using the Nitric
 Acid Digestion  Procedure (SM 302D).
 Column Treatment and Cleanup

     One column of each contaminant pair received only tap water
 rinses while its sister  column  received the chemical counter-
 measures, water  plus  surfactant (Rinse 2) and  water plus
 chelating agent (Rinse 6). Columns receiving only tap water were
 rinsed 15 times in pore volume aliquots (690 ml). Columns which
 received the surfactant and EDTA solution received a total of
 eight rinses, one surfactant rinse, one EDTA rinse and six tap
 water rinses. Initial and final pH, metal content, and COD were
 recorded for each rinse.

 RESULTS AND DISCUSSION

    From the shaker table analysis, plots of adsorbance versus
 time were prepared for each concentration of each metal. Figure 4
 shows an example of cadmium adsorption. From each plot, the
 final adsorbance was estimated and presented as total percent ad-
 sorbance and total mg metal adsorbed per gram of soil as well as
 the equivalent (m-moles) metal adsorbed per gram of soil (Table
 4). The shaker table results were used to estimate a "minimum"
 contact time between soil and contaminant to achieve a heavily
 contaminated soil and to determine if the time to reach equilibri-
 um is a function of initial contaminating concentration. Data in-
 dicated that six hours of agitation achieved maximum adsorption
 values for the contaminant concentration tested, with a longer
 time needed  for the lower concentrations. The shaker table data
 were also used to generate adsorption isotherms, a graphical pres-
entation of the mass of metal adsorbed per gram of soil versus the
residual metal contaminant concentration in the contact solution.
Table 4  (showing the format of data generated for each metal)
-------
                 METAL MIGRATION IN SOIL
     lUO -I
                       INITIAL CADMIUH CONCENTRATION  MO HG/L
                              It

                         TIME - HOURS
           Figure 4.  CADMIUM ADSORPTION
                  - SHAKER TEST ANALYSIS

Table 4.  SHAKER TEST RESULTS - CADMIUM ANALYSIS
A) 24 Hour Test — Liquid Sample Analysis
      Initial     Final     Reduction
Cone, Cone, Cone,
No mg/l mg/l mg/l
1 30000 26000 4000
2 2200 1300 900
3 320 175 145
4 26 12 13
B) Soil Sample Digestion Analysis
Digested Soil
Initial Sample Sample
Cone, Cone, Mass, Adsorbance,
No mg/l mg/l g mg/g
1A 30000 7000 3.423 133
2A 2200 160 3.567 2.33
3A 320 150 3.041 2.46
4 A 25 2.25 3.224 0.041
Adsorbance,
mg/g
40
9
1.45
0.13
Equiu Equiu
Cone, Cone,
Removed, Remaining,
mg/l mg/l
13300 16700
233 1967
246 74
4.07 20.9
Adsorbance,
percent
13
41
45
52
Adsorbance,
percent
44
11
23
84
                       C.C. CONNICK

Table 4.  SHAKER TEST RESULTS - CADMIUM ANALYSIS
                      (CONTINUED)
C) Summary
Concentration
Remaining,
No mgTl mM/l
1
2
3
4
1A
2A
3A
4A
26000
1300
175
12
16700
1967
74
21
231.3
11.6
1.56
0.107
148.6
17.5
0.658
0.187
Log-Cone
Remaining,
mM/l
2.36
1.06
0.19
-0.97
2.17
1.24
-0.181
-0.731
Adsorbance,
mg/g
40
9.0
1.45
0.13
133
2.33
2.46
0.041
mM/l
0.356
0.080
0.013
0.0012
1.183
0.021
0.022
0.00036
Log
Abs.
mM/l
-0.449
-1.10
-1.89
-2.94
0.07
-1.68
-1.66
-3.44
summarizes the data required for isotherm generation based on li-
quid sample analysis. Part B presents the results of the digested
soil samples. Part C is a representation of data in Part A and B,
expressed in units necessary for  plotting the two types of
isotherms.

    A comparision of the percent adsorption columns in Part A
and Part B of the summary  tables showed that the digested soil
samples  consistently  varied  from  the  corresponding  li-
quid/leachate samples. The soil sample analysis consistently in-
dicated  a lower  value  for total  metal adsorbed than did the
filtrate analysis.  An explanation for this trend is that the soil
digestion process  does not remove all the  metal adsorbed,
therefore, total adsorbance is underestimated by the soil sample
analysis.

    The isotherms developed were prepared using the Freundlich
(Figure 5) and Langmiur equations (Figure 6). The Langmiur ad-
sorption isotherm equation1 can be derived from simple ion ex-
change considerations,  assuming that only one type of adsorp-
tion site is involved and  that only simple heavy-metal  cations
take part in the exchange reaction (1-site model). The Freundlich
isotherm1 equation can be interpreted as an approximate descrip-
tion of ion exchange involving one or more types of heavy metal
cations and one or more types of adsorption sites (2-site model).
-------
                 MKTAL MIGRATION IN SOIL
   10° -,
             COLUHIi TCStS

        	Xmumi 111111*1 ADSORPTION BUMF.

         Q  -PMOICHD INITIAI AOSOMMOII

         O  -NIASlHtO INITIAL ADSOIMION
                                SHOO HSU

                           • -IIQUIO SAHflf ANAIYSK

                           A -SOLID SAHnt ANALYSI!
                                 lSQTnt»n

                           IOC ADS. • 0.«S« I IOC COdC. -*

                                • • O.»»l   I • (
      10-*       ID'1       10°       to1        10*        10'
                  KSIOUAl COIlCCNTIAtlOII - MILIINOICS/I lit*

Figure 5. FREUNDLICH ISOTHERM - CADMIUM ADSORPTION
 cr\
 rv>
   10' :
   10'
   10"
SHA>» TAIH ANALYSIS

• - LIQUID SAHUt ANALYSIS

* • SOIIO S««nt ANALYSIS
                               ISOTH[»M

                    ADS • l/(l>l.4  I I/CONC • tl.tl)

                    I • Q.il*     N . ft

                    tuiihur MIOICKO Aosoimo*

                      • I/M • O.OIOS NIILINOIES/IITU
       10-'       I0-*       10"'       10°        10*        10*
                   ItSIDUAL CONCCNTIATION .  I/(HI LIIMOLCS/lI TCI I

Figure 6. LANGMUIR ISOTHERM - CADMIUM ADSORPTION
                        C.C. CONNICK

    From the plots and their corresponding correlation coeffi-
cients, it can be seen that for all five metals the Freundlich equa-
tion corresponds well with the adsorption data generated in the
study of this soil and contaminant system. The Langmiur equation
corresponds well only with data generated from the adsorption
behavior of Pb, Ni, and Zn.
    An explanation  for  the  correlation of the data  to the
Langmiur equation for only Pb, Ni, and Zn is that these ions are
not complexing in solution to the same degree as Cd and Cu and
they are adsorbing to the soil based on the mono-layer theory
with more uniform bonding strengths. Excessive complexing of
Cd and Cu in solution would cause adsorption on the soil surface
to be less  uniform with varying strengths of attachment and.
therefore, be more accurately described by the Freundlich theory.
Support of this hypothesis is found  in a study by B.E. Blom*
which determined that in the presence of a relatively large excess
of calcium or potassium the formation of CdCr enabled the Cd to
be more easily bound to the soil system due  to the preference of
univalent ions over multivalent ions.  The soil used by  Blom was
similar in  type to the Typic  Hapludult soil type used  in this
study, although the calcium content of the Typic Hapludult soil
was not determined. It can be hypothesized (but not proven) that
Cd was adsorbed as CdCr in this study. During AA analysis, the
flame appeared red and yellow in color, indicating the presence of
significant levels of calcium and sodium respectively, in the liquid
sample.
    Considering the theoretical aspects of the two isotherm types
and the better agreement of the Freundlich equation to the data
generated, the Freundlich isotherm was selected for use during
soil column evaluation. The isotherm plots also contain a dotted
line which represents a family  of potential adsorbance versus
residual concentration end points. The line was formed by select-
ing a series of arbitrary final concentrations and,  using  the
change from the initial concentration, calculating the unique ad-
sorbance that could occur. The predicted adsorbance of the metal
in the column at the initial contaminant concentration applied is
designated at the intersection of the isotherm line by the square
-------
                 METAL MIGRATION IN SOIL
symbol. The actual adsorbance measured for the metal by the soil
column is designated by the hexagon symbol. The optimum con-
tamination obtained in the columns was consistently lower than
that obtained in shaker tests.  This is due  to  the greater
contaminant-to-soil ratio in the shaker test and also the improved
soil-liquid contact achieved during the agitation process, as com-
pared to the gravity flow conditions in the soil column.

    Adsorption of the metal contaminants achieved by the soil
column were: Cd. 0.083 mM/g; Cu, 0.023 mM/g; Pb. 0.030 mM/g;
Ni. 0.073 mM/g; and Zn, 0.132 mM/g. These values are about 70
percent of the values predicted  to be adsorbed based on the
shaker test analysis.
Soil Treatment and Decontamination
    Table  5  presents the percent removals of the metal con-
taminants by each treatment method. The tap/surfactant/EDTA
8-rinse treatment was more effective than the 15 tap water rinse
in all cases except lead. An increase of metal concentration in the
leachate following the application of the EDTA/buffer solution
indicates that EDTA is responsible for the increased removals in
these columns. Metal concentrations in surfactant leachate are
equivalent or less than the concentrations in the leachate of the
corresponding tap water rinse from its sister column, indicating
that the surfactant  was ineffective in desorbing heavy  metals
from soil systems. This is shown in Figures 7 and 8. The shape of
the removal curves indicates the majority of the metal is removed
in the first four to five rinses. The column receiving the EDTA

     Table 5.  TOTAL PERCENT METAL REMOVED
              Tap Water Only,
     Metal       15 Rinses
      Cd             87
      Cu             44
      Pb             74
      Ni             87
      Zn             88
Tap/Surfactant/EDTA,
 	8 Rinses	
        100
         82
         63
         94
         93
                                                             C.C. CONNICK
                                      o
                                      o
                                      «J
                                        102-
 10'
                                                                     A - INITIAL CONCENTRATION

                                                                     • - TAP  WATER RINSE
                   4       6       «      10

                   RINSE VOLUME - LITERS
                                                       U
Figure 7.  CADMIUM COLUMN TEST - WATER RINSE
-------
        METAL MIGRATION IN SOIL
                   • - INITIAL CONCENTRATION
                   A - TAP HATER RINSE
                   i - SURFACTANT RINSE
                   A- EDTA RINSt
             4       6       8      10

             RINSE VOLUME - LITERS
                                        I?
                                               14
Figure 8.  CADMIUM COLUMN TEST TAP
      WATER/SURFACTANT/EDTA RINSE
                       C.C. CONNICK

solution experienced a marked decrease in permeability. This in-
dicates that the increase of the system pH due to the addition of
the EDTA buffer mixture is causing the  precipitation of the
metals,  presumably  as hydroxides. (Precipitants were also
observed in the leachate from the EDTA treated columns.)

    EP  Toxicity analysis performed in  the  soil following the
treatment rinses indicated that five pore volumes of tap water (or
tap water plus surfactant) were successful in reducing the metal
content of the  soil contaminated  by zinc, copper and lead to
within EP Toxicity limits, but only with the application  of the
EDTA/buffer rinse was the soil contaminated with cadmium and
nickel reduced to levels within EP Toxicity  limits. Using rain
data for the area of the soil origin, the pore volume of rinse ap-
plied was equated to 0.34 years of rain.

CONCLUSIONS

    Results of  this study  indicate that in-situ  treatment is a
viable solution for the removal of metals Cd, Cu. Pb, Ni and Zn
from contaminated soil. Care must be taken when extrapolating
the results obtained in these tests to other situations as there are
many variables which influence detoxification.

    The use of the surfactant mixture as a rinse treatment for the
removal of heavy metals proved ineffective in this soil system.
The surfactant solution provided  removal efficiencies com-
parable, but not superior to the tap water alone rinses.

  EDTA proved effective in desorbing the metal cations from the
soil system. The columns which received only eight treatment
rinses, one of which included EDTA. indicated greater removals
of contaminant than the columns which received 15 rinses of tap
water alone. The use of EDTA appears to flush the metal from
the soil as observed from the very high metal content  of the
EDTA rinse leachate in comparision to the previous tap water
rinse leachate from the same column.

  A decrease in the permeability of the column is observed when
a large volume of treatment rinses is applied. This occurs in part
-------
OS
VJ1
                 METAL MIGRATION IN SOIL

because the fines are washed to the base of the column where they
accumulated  and  inhibit the flow.  The  application of  the
EDTA/buffer solution increases the system pH to 9 to 10 which
induces the formation of precipitates within the column, further
decreasing the column permeability and  potentially clogging it.

    Maximum adsorbance of the metal by the soil under shaker
table anaylsis was obtained within the first three to six hours for
contaminant concentrations greater than approximately 20,000
mg/1. The required contact time increased to six to twelve hours
for contaminant concentrations between 20,000 mg/1 and 20 mg/1.
At contaminant concentrations less than 20 mg/1, the time to
equilibrium was as long as 18 hours.

  The  Freundlich isotherm appeared to be applicable for  the
description of the  adsorption behavior of all  the  soil/metal
systems in this study. This implies that the adsorptive sites in
the soil system are heterogeneous and a possible interaction
among particles in the adsorbed  phase  may be occurring. The
energy of this adsorption decreases logarithmically as the frac-
tion of surface covered increases.

  The Langmiur isotherm only successfully described the adsorb-
tive behavior of Pb, Ni. and Zn. The Langmiur adsorption equa-
tion is derived from simple ion exchange considerations, assum-
ing that only one type of adsorption site is involved and that only
simple heavy metal cations take part in the exchange reaction.
The fit of Pb. Ni and Zn adsorption results to the Langmiur equa-
tion may indicate that these ions are not complexing in solution
to the same degree as Cd and Cu and that they are adsorbing to
the soil based on the mono-layer theory with more uniform bond-
ing strengths.

REFERENCES

1. Ellis, W.D. and J.R. Payne, "Chemical Countermeasures  For
   In-Situ Treatment of Hazardous Material Releases", USEPA
   Contract No. 68-01-3113, Oil and Hazardous Materials Spills
   Branch, Edison, NJ, 1983.
                                                                                                    C.C. CONNICK

                                                                              2. "Final  Report:  Underground  Movement  of Gasoline  in
                                                                                Ground Water and Enhanced Recovery  by Surfactants",
                                                                                Texas Research Institute, 1979.
                                                                              3. Drake, E. et aL, "A Feasibility Study of Response Techniques
                                                                                For  Discharges  of Hazardous Chemicals that  Disperse
                                                                                Through the Water Column", US  Dept. of Transportation,
                                                                                Report No. CG-D-16-77, 1976.
                                                                              4. US EPA, Federal Register, Vol. 45, No. 98, Rules and Regula-
                                                                                tions, Appendix II,  p. 33127.
                                                                              5. Shepard, J., Submarine Geology, Harper and Row Publishers.
                                                                                NY,  1973.
                                                                              6. Black, C.A.,  ed.,  Methods of Soil Analysis,  Chemical and
                                                                                Microbiological Properties, Agronomy No. 9, Part 2, 1965.
                                                                              7. Metcalf and Eddy, Inc., Waste water Engineering: Collection
                                                                                Treatment and Disposal, McGraw Hill, NY, 1972.
                                                                              8. Blom, B.E.. "Sorption  of Cadmium  by Soils", National Sci-
                                                                                ence Foundation, June,  1974.
-------
166
-------
  	!    UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
\LMP4?              OFFICE OF RESEARCH AND DEVELOPMENT
                HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
                               CINCINNATI. OHIO 45268
                                                     REPLY TO:
                                                     Releases Control Branch
                                                     U.S. EPA
                                                     Woodbridge Avenue
                                                     Edison, New Jersey 08837

DATE:     December  19, 1985

SUBJECT:  Draft Research Project Plan:  Removing Lead with EDTA Chelating
          Agent from  Contaminated Soil at the Michael Battery Company,
          Bettendorf, Iowa

FROM:     Richard P.  Traver, Staff Engineer
          Releases Control Branch, LPCD, HWERL

TO:       James R. MacDonald, Environmental Engineer
          Site Investigation Section, Emergency Planning
            and Response Branch, ESD - Region VII

THRU:     Frank J. Freestone, Chief
          Technology  Evaluation Staff, RCB, LPCD, HWERL
    This is in response to your request to Ira Wilder for an estimate to use
the EPA Mobile Soils Washing System at an Immediate Removal  Action at the former
Michael Battery Company, Bettendorf, Iowa.

    Attached is a Research Project Plan for your review and  comment.  The pro-
posed project consists of the following four phases:

    Phase I   	 Preliminary Laboratory Feasibility Study for Evaluating
                     Potential Use of EDTA Chelating Agent for Removing Lead
                     from Michael  Battery Soil

    Phase II  	 Laboratory Feasibility Study for Evaluating Removal of
                     Chelated Lead from EDTA Solution, and Preliminary Process
                     Design

    Phase III 	 Full Scale Pilot Study

    Phase IV  	 Field Demonstration
   *

    The objective of the proposed  project is the development of operating proto-
cols and cost estimating procedures that could be used by Region VII to engage
the services of a commercial cleanup company or those of an  existing EPA cleanup
contractor.  We are flexible regarding the extent to which this plan needs to be
implemented and we stand ready to  discuss any modifications  you might suggest to
suit your purposes.
                                      167
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Draft Research Project Plan
    We regret the delay In our response to your  request.   The  basis.of  the
attached project plan is the result of similar estimating  efforts  for lead  con-
tamination in Boston, and the research and demonstration efforts for lead-
contaminated soil treatment in EPA Region  V  at Lee's  Farm, Woodville, Wisconsin.
Hopefully, the additional time taken will  provide  Region VII with  a more  complete
plan due to our newly acquired understanding of  heavy metal contamination and
remedial alternatives.

    If you have any questions on the plan, please  do  not hesitate  to contact me
(FTS-340-6677) or Frank Freestone (FTS-340-6632).   Please  let  me know your  view
of "where to from here."

Attachment
cc:  R. Hazel, Reg VII
     A. Zownir, ERT
                                       168
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                            DRAFT RESEARCH PROJECT PLAN

         REMOVING LEAD WITH EDTA CHELATING AGENT FROM SOIL CONTAMINATED
                           WITH LEAD IN BETTENDORF, IOWA

                    OPTION B:  On-Site Treatment/Soil Washing

                                 December 19, 1985


OBJECTIVE

The overall objective of this project is the development of engineering speci-
fications, cost estimates, and operating protocols for use by Region  VII to
evaluate the alternative of soils washing for treatment of lead-contaminated
soil, defined as Option B under the Region VII Action Memorandum of 8/28/85.
If this alternative is subsequently implemented for a full-scale cleanup, the
treatment of substantial quantities of contaminated material  at  the Michael
Battery Company could be pursued under either a separate contract with  a haz-
ardous material cleanup company or under the appropriate EPA Emergency  Response
Cleanup Services contract.


SUMMARY AND LIMITATION OF SCOPE

The Hazardous Waste Engineering Research Laboratory's Releases Control  Branch
(RCB) in Edison, NJ, has been asked by EPA Region VII to evaluate the feasi-
bility of removing lead from contaminated soils at the Michael Battery  Company,
located in Bettendorf, IA.  Previous work by RCB and others*-? has shown that
lead may be removed from some soils using EDTA as a chelating agent in  an aqueous
solution to solubilize the lead, with subsequent removal and concentration of
the lead from solution.  This Research Plan addresses a multi-phase engineering
feasibility study only, and does not explore other aspects of the lead-in-soil
problem at the Bettendorf Site such as:  a detailed "extent of contamination"
survey, or means of solving the contamination problem other than by processing
the soils.  It should be further noted that removal and treatment of  contami-
nated soils may be limited to collected dust/soil from the main  building, the
approximate 535 cubic yards of soil from site drainage ditches,  and the approxi-
mate 300 cubic yards from around the building.


BACKGROUND

    1.  Site Description - The information Pertaining to the Site Description  is
                           Basically a Summary of Information Provided  in James
                           R. McDonald's Draft Action Memo of 8/28/85.
    *
The Michael Battery Company operated a battery manufacturing and recycling busi-
ness in Bettendorf, Iowa, from October 1979 thru June 1983.  Michael  Battery
Company leased the 0.6 acre site and a 5,000-square-foot metal building from the
present deeded owner, Jessee Roofing and Painting Company.  The  site  is located
                                       169
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 in  an  industrial area of Bettendorf within the floodplain of the Mississippi
 River  which  is  located approximately one half mile south.  Surface run-off from
 the battery  manufacturing operation has contaminated portions of the adjacent
 property.

     The subsurface geologic characteristics are the bedrock, which 1s approxi-
 mately 10-15 feet below the surface, and the 0-10 feet of unconsolidated
 sediments which are alluvial silts, clays and fine sands.  The upper surface  has
 received crushed limestone to level the surface and to serve as footings for  the
 building.  The  hydrology in the area consists of the surface water, groundwater
 in  the unconsolidated alluvial deposits, and the deep bedrock aquifer.  The sur-
 face water and  storm runoff is largely contained 1n the industrialized area
 around the site, and is eventually diverted to the Mississippi River.  Local
 drainage from the Michael Battery Company site 1s to the south, over the adjacent
 Rogan  Scales property, Into a railroad ditch draining west.  The runoff In the
 ditch  ponds  and percolates Into the substrata.  The Davenport Water Company has
 water  intakes on the Mississippi River, 3.75 miles downstream from the site.
    A.  Quantity and Types of Substances Present

In February 1982, 1n response to a report of Illegal  dumping of sulfuric acid  at
the site, preliminary soil and surface water samples  were collected.   These pre-
liminary samples identified heavy metal contamination of both soils and surface
waters.  Followup sampling conducted by EPA on July 8, 1982, detected lead con-
centrations in soil up to 5,200 ppm.  In response to  these sampling efforts, an
expanded EPA field investigation was conducted in April  1984.  On site monitoring
wells were installed in June 1984.  The results of the above Investigations have
indicated that significant lead contamination exists  on site.  The areas of lead
contamination have been divided Into four subareas:   (1) metal building; (2)
western drainageway; (3) sump area and eastern drainageway;  and (4) storage areas
around the building.  The concentrations of lead and  the volume of lead-contami-
nated soil/dust In each area are summarized below:

        1.  Interior Dust/Soil Samples

Concentrations of lead 1n dirt and dust collected from inside the 5,000 square
foot metal building, ranged from 4% to 5% for EPA samples collected in June, 1984,
and from 17% to 33% for the National Institute of Occupational  Safety and Health
(NIOSH) samples collected in November, 1984.  Dust has settled  throughout the   ;
building on walls, roof and floors; with notable concentrations on the roof trus-
ses and cross member supports for the walls and loft  area.  An  estimate of the
quantity of dust/soil that could be vacuumed from the building  would be approxi-
mately ten 55-gallon drums.
                                       170
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        2.  Western Drainage Samples

The western drainage from the Michael  Battery Company  site is  directed  south  from
the blacktop around the building, southwest across  Rogan Scales  property,  flow-
ing west in the drainage ditch to the  southwest  corner of the  lot.   Concentrations
of lead in this drainageway varied from 65 ppm to 31,700 ppm and averaged  over
4,000 ppm.  Soil samples were collected to a depth  of  12 inches; if subsequent
soil sampling below the 12 inch depth  reveals further  lead contamination,  quanti-
ties of soil to be processed could be  dramatically  increased.  The  length  of  the
western drainage ditch is approximately 150 feet.  The surface area of  the sur-
rounding contaminated drainage area is approximately 13,000 square  feet.   The es-
timated volume of contaminated soil, assuming an average depth of one foot, is
480 cubic yards.


        3.  Sump and Eastern Drainage  Samples

Drainage from the sump at the loading  bay at the east  end of the building  was
pumped onto the shoulder of Devils Glen Road where  it  drained  south to  the drain-
age ditch beside the railroad and then drained west.   Concentrations of lead  in
this eastern drainage varied from 94 ppm to 9,600 ppm  and averaged  4,600 ppm.

The length of the Devils Glen Road shoulder from the sump to the drainage  ditch
south is approximately 150 feet.  The  surface area  of  the surrounding contami-
nated area is estimated to be 1,500 square feet. The  estimated  volume  of  con-
taminated soil, assuming an average depth of one foot, is 55 cubic  yards.


        4.  Storage Areas Around the Building

The highest concentration of lead found (102,000 ppm)  was located outside  the
backdoor where Michael Battery Company sorted lead.  Other storage  areas in-
cluded an area north of the blacktop adjacent to the auto parts  warehouse;
concentrations range from 74 ppm to 5,300 ppm and average 1,000  ppm. A second
storage area is located to the west of the blacktop area; concentrations range
from 210 ppm to 2,300 ppm and average  770 ppm.

Sweeping of soil/dust from the asphalt surfaces  would  result in  an  estimated
five 55-gallon drums of material.  The unsurfaced area on the  site  with potential
storage, not including the western drainage-way, is estimated  at 8,000  square
feet.  The estimated soil volume assuming a one  foot depth is  300 cubic yards.


        5.  Surface Water and Groundwater Analysis

Previous sampling efforts have documented moderate  lead contamination of sur-
face drainage waters (96 ppm).  No significant groundwater contamination has
been detected, however.
                                       171
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REMEDIAL ACTION

Based on CDC advisories, a clean-up level of 1,000 ppm lead in soil  is recom-
mended.  Soils which fail the E.P. Toxicity Test for lead, it is proposed, would
be handled as hazardous waste and transported to a licensed hazardous waste site
for disposal.  Soils which do not fail the E.P. Toxicity Test, but which contain
lead in concentrations above 1,000 ppm, would be disposed of at a state approved
landfill.

Region VII1s Remedial Action Plan calls for cleaning the interior of the building,
including the roofing, trusses, walls and floor of all dirt/dust.  This would be
accomplished vacuuming with a High Efficiency Particulate Air (HEPA) filter fol-
lowed by pressurized water and detergent wash.  The use of a chelate solution of
EDTA should be considered for the wash solution.  This would allow for the col-
lected wash solution to be treated and recycled.  The concentrated lead would be
either disposed of as a hazardous material, or could be sold to a metal refinery
to be reprocessed.

Region VII has proposed three action options:  Option A - Dig and Haul, Option B -
Soils Washing, and Option C - On-Site Chemical Fixation and Capping.  Options A
and C are briefly summarized with a detailed explanation of Option B following.
OPTION A - DIG & HAUL

Region VII's Option A calls for excavation and off-site disposal  of soil  and
materials having lead concentrations in excess of 1,000 ppm.  It  is estimated
that the volume of soil and lead dust would approach 900 cubic yards.   It is
presumed that 75% of this material (675 cubic yards) would not fail E.P.  Toxic-
ity criteria for lead (£ 5 mg/1 1n leachate) and would be suitable for disposal
in a state approved landfill.  The remaining material, approximately 225  cubic
yards, 1s expected to fall the E.P. Toxicity Test and would be handled as a
hazardous waste.  Disposal of this material would be carried out  at an approved
Resource Conservation and Recovery Act (RCRA) disposal site.  Cost estimates are
approximately $214 K if only a portion of the material must be disposed of at a
RCRA approved site.  If all material must be taken to a RCRA site, the cost
estimate is $463 K.  It should be noted that this Option does not eliminate the
contamination problem, but merely relocates it until such time that the RCRA
site material would have to be treated.
                                       172
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OPTION C - ON-SITE CHEMICAL FIXATION & CAPPING

Region VII has proposed a commercial chemical fixation process for on-site en-
capsulation.  This approach would stabilize the contaminated soil  through  a pro-
prietary fixation process.  The fixated soil would be replaced on-site and then
covered with a clean soils cap.

With the approximate 1125 cubic yards of material, the rough cost  for on-site
chemical fixation is $100/cubic yard, or $112 K.  An additional  estimated  $60 K
would be needed to install a clean soil cover.

No laboratory analysis has been performed evaluating the effectiveness of  chemi-
cal fixation with the site specific Bettendorf Soil.  A thorough bench-scale
study would be necessary in order to determine if the fixated soil  would pass the
E.P. Toxicity Test for lead.  It is also uncertain if the site would  be usable
by the owners following the chemical fixation process.


OPTION B - SOILS "WASHING" USING EDTA

The soil decontamination process first used by RCB was at a lead-storage type
battery reclamation site in Leeds, Alabama, in 1984, at the request of Region  IV.
This involved the use of a prototype "Soils Washing System" for application of
13% EDTA solution to lead contaminated soil.  The lead-in-soil  concentration was
reduced from 50,000 to less than 100 ppm.  EDTA or ethylenediaminetetraacetlc
acid, disodium or tetrasodium salt, is a commercially produced chelating agent
that, in an aqueous solution, can complex with lead to produce a water soluble
chelate. (See attached Project Summary and Fact Sheet for more detail  on the de-
sign and operation of the EPA prototype Soils Washing System.)

Region V has subsequently evaluated various treatment processes for the cleanup
of a battery reclamation site at Woodville, Wisconsin.  After examining the ORD
experience and conducting laboratory tests, Region V also chose washing with
EDTA as the best approach.  A pilot-scale system is now being implemented  in the
field for treatment of battery casings.

A literature search and laboratory study, performed by JRB Associates under the
Hazardous Waste Engineering Research Laboratory's "Chemical Countermeasures Pro-
gram," also established the use of EDTA as the likely technology for  the removal
of a variety of heavy metals from soils.  The study noted that lead-in-soil wash-
ing with EDTA must be evaluated on a site-specific basis.  An independent  study
conducted by Northeastern University, in cooperation with RCB, corroborated these
findings.
                                       L73
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A significant concern at this time is not knowing the percent of EDTA that  can
be  regenerated for reuse.  Chelate that cannot be regenerated causes a double
expense:  one, it must be replaced; and two, it must be disposed of in a safe
manner.  Apparently, iron blocks the regeneration process.   In the Alabama  work,
iron is listed at 2,100 mg/kg and apparently, although not  specifically noted,
the EDTA regeneration was only 5% through sulfide precipitation.  The iron
content of the alluvial silts, clays and fine sand at the Bettendorf site is
approximately 1-2% in the form of hematite, magnatite and ilmenite.  Dr. Anderson
of the Geology Department of Augustana College (across the  river from Bettendorf)
indicated that the Mississippi River received a "slug" of Iron from Wisconsin in
that area in the last ice age.  If this is the case, there  is, on the average,
three times as much iron as there 1s lead.  This would be expected to cause sig-
nificant problems in regenerating the lead if the chelate can remove the iron
from these mineral structures.  For this reason, a thorough comparison on a lab-
oratory scale basis needs to be run on both sulfide precipitation and electrodi-
alysis as means for EDTA regeneration.


SCOPE OF WORK

The response activities proposed by RGB for dealing with the lead problem in
Bettendorf consist of four phases.  Phase I will be a laboratory feasibility
study to determine if EDTA offers a reasonable chance of success for removing
lead from the type of soil matrix present at the affected Michael  Battery site.
Phase II will also be a laboratory-scale engineering study  geared to determine
the optimum approach and conditlons'for removing chelated lead from solution
and regenerating EDTA for recycling purposes.  If these phases are successful,
Phase III will  be a full-scale pilot study Involving approximately 100 drums
of lead-contaminated soil being shipped to Edison, New Jersey, where the ORD
Soils Washing System will be used to evaluate process performance, operating
costs, and system capacity.  Additionally, Phase III will provide for any
necessary permit applications, Including a delisting petition.  Phase IV will
be a field activation with the Soils Washing System at the  Michael Battery
site to demonstrate the field capability of the technology  and to develop oper-
ating protocols for use by Region VII in acquiring contracted cleanup services,
If so desired.
Phase I    Preliminary Laboratory Feasibility Study  for  Evaluating  Potential
           Use of EDTA Chelating Agent for Removing  Lead from Bettendorf Soil

The objective of Phase I  1s to establish the optimum concentration  of  EDTA 1n
solution for lead removal  and the percent lead reduction In  the  Bettendorf soil
-------
 A  2-4  kg sample consisting of a homogeneous blend of "Michael Bettendorf Site
 Soil"  contaminated with 2,000-330,000 ppm lead will be obtained by Region VII
 by compositing samples from several hot spots.  Region VII will attempt to make
 this single composite sample as representative as practicable of the soils in
 the hot spots in terms of organic content, soil particle size, and potentially
 interfering elements such as Zn, Ba, Ti, Cr, and Fe.

 It  should be noted that this preliminary study is a single sample study only--
 the results must, therefore, be interpreted with great caution.  Soil  variabil-
 ity among the hot spots could easily be obscured in the blending process needed
 to  obtain the single "representative" sample.  Phase II will  include samples
 from a greater number of locations such that an analysis of the variability of
 key parameters of the soils to be treated can be made.

 The single sample will be "washed" with EDTA solution in the laboratory to deter-
mine the effectiveness of the EDTA chelating process.  Ten gram (10g)  soil por-
 tions will be agitated on a "shaker table" for 30 minutes with one hundred mini-
 liter (100 ml) volumes of the following percentages of EDTA (disodium  salt) in
 water:

                  0 (blank);  1.0;  2.5;  6.5;  13.0;  and  25.0


Analyses will then be performed to determine the amount of lead removed by EDTA
washing and lead remaining on treated soil.

An  EP Toxicity Test (40 CFR 261.24) and a qualitative analysis for all  metals
 present in the Bettendorf soil  blend will also be performed to determine some
of the soil's characteristics.

The QA/QC program for this Phase I study will have the single sample limitation
as noted above, and will  include the following:

[a]  The soil washing and analyses procedures will be performed in duplicate.

[b]  At least three replicate portions of the original  Bettendorf soil  blend
     will  be analyzed to assure homogeneity.

[c]  "Lead in Soil" analyses will  be performed using both X-Ray Fluorescence and
     Acid  Digestion methods.

[d]  Analyses performance will  be evaluated using "QA Audits" with primary em-
    . phasis on Performance Evaluation Audits.
                                       175
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A reduction of lead content in soil to approximately 1,000 ppm is currently con-
sidered successful for Phase I.  If unsuccessful. due to the possible presence
of interfering compounds (e.g., iron) that limit the performance of EDTA, a more
intensive laboratory effort (not fully described in this Plan) may be necessary.
This subsequent effort would seek to define alternative chelating agents or
entirely different treatment processes.  If successful  and an adequate reduction
of the soil lead level is achieved with EDTA, Phase II  will  be implemented.

It should be noted that some residual EDTA will remain  on the treated soils along
with residual lead (and probably other residual substances).  There is a possi-
bility that the residual EDTA could cause the residual  lead to have a greater
environmental mobility than that experienced by an equivalent concentration of
lead prior to the treatment process, or the EDTA may, Itself, pose some type of
toxicity problem.  While the reported 1059 of EDTA is 2 g/kg (rats, orally), and
toxicity does not appear to be an obvious problem, these aspects of the use of
EDTA will be investigated on a preliminary level during this initial  laboratory
study phase.  Assistance from other ORD offices may be  needed for answers to
these questions.


Time Frame ...  15-30 days from receipt of "representative"  sample.

Cost  	  $10,000 - $15,000

Product 	  Letter report on the preliminary feasibility of EDTA extraction.

Phase II    Laboratory Feasibility Study for Evaluating Removal  of Chelated Lead*
            from EDTA Solution, and Preliminary Process Design

The objective of this phase is to establish the optimum treatment process for the
recovery of lead and EDTA from the "soil wash" solution and  to prepare preliminary
engineering process specifications, a detailed cost estimate, a test  plan, and a
schedule for Phase III.

The EDTA recovery process used by ORD at Leeds, Alabama, reacted sodium sulfide
with the EDTA-lead chelate to form a lead sulfide precipitate that was dewatered
and disposed of at a smelter.  Subsequent acidification of the remaining EDTA
solution enabled substantial  recycling of EDTA.  An alternative treatment process
for the removal  of lead from solution is based on electrolytic reduction and may
be potentially more cost-effective than the use of sodium sulfide.  Evaluation of
final disposal  or reclamation of the EDTA (e.g., solidification for storage) will
be pursued.
                                       176
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Additionally, further testing with a selected concentration of EDTA on several  sep-
arate "representative" samples from hot spots (the inverse program of Phase I)  will
be performed to determine if variability of soil parameters will  cause unacceptable
treatment system performance changes among the various soils to be treated.  Each
soil sample will be analyzed for particle size, organic content,  presence of other
metals or other interfering compounds, and other parameters that  could affect per-
formance of either the EDTA extraction or the recycle of the EDTA.  This testing
will be performed with QA/QC similar to that in Phase I to assure reliability and
reproducibility of data. The samples will be obtained through coordination with
Region VII.

At this time, it will be necessary to assure that the soil samples received are
reasonably representative of those expected in the field.  Subsequent project ele-
ments (Phases III and IV) are considerably more expensive than these laboratory
phases and rely heavily upon the precision and accuracy of the laboratory data.

Once an EDTA recovery process is identified, the necessary process equipment for
executing the entire treatment (lead removal with EDTA recycle) at pilot scale
(Phase III) must be identified and sources sought for needed equipment not now on
hand (e.g., dewatering equipment for lead sludge or electrolytic  lead removal  cells)

Finally, a detailed cost estimate, testing protocol, including a  Sampling and
Analysis Plan and a Quality Assurance Project Plan, and schedule  for Phase III  will
be prepared.


Time Frame ...  30-60 days from receipt of authorization to proceed.

Cost  	  Laboratory work:                 $10,000-$!5,000
                Detailed Engineering Planning:   $50,000-$!35,000

Product 	  Letter report providing the results of Phase II and detailed
                planning information for Phase III as noted above.

Phase III    Full Scale Pilot Study

The objective of this phase is to obtain engineering information  on the unit cost,
capacity, personnel requirements, and treatment effectiveness of  lead removal  using
EDTA in the EPA soils washing system, and to provide preliminary  planning infor-
mation for Phase IV.

The study will simulate a field activation using the full-scale prototypical equip-
ment* in Edison, New Jersey.  Equipment needed for the treatment process but not
currently on hand will be acquired or leased, whichever is more favorable.  The
buy/lease decision will be made during Phase II, such that the estimate for Phase
Illis as accurate as possible.
                                       177
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The tests will involve the following sequence of activities:

1.  EPA and contractor personnel involved with the proposed tests will  be provided
    with operator training, safety training, and medical  monitoring  as  appropriate.

2.  Equipment will be set up indoors in a suitable area where the testing can  be
    conducted safely and in an environmentally suitable manner.

3.  Initial process shakedown will be conducted using clean soils to assure that
    all elements of the process function properly individually and together.   Such
    normal operating activities as determining pump capacities and flow balances
    among the various unit processes must be performed carefully  and on clean
    material.  During this activity, minor process adjustments will  be  made to
    assure appropriate system function in the absence of  contaminants or treatment
    chemicals.

4.  Clean soil of a type reasonably similar to the Bettendorf soil will  be inten-
    tionally contaminated with lead known to be in similar form and  concentration
    as the lead from the Michael Battery site and control Ted-condition  tests will
    be performed, first at laboratory scale, then at pilot scale  to  assure that the
    treatment process is operating properly.  (This is done to reduce the amount of
    Bettendorf soil that must be transported to Edison for the shakedown portion of
    the tests as opposed to the portion of the tests intended for data  gathering.)
    This activity will assure that the treatment chemistry 1s operating properly
    and that such steps as EDTA addition, addition of other treatment agents,  and/
    or removal/recycle of the EDTA are functioning properly.

5.  Approximately 100 - 200 (55 gal.) drums of lead-contaminated  soil will be  ob-
    tained from Region VII and used 1n a set of tests (probably three or four
    "runs") designed to provide capacity and performance  Information.   The samples
    contained in the drums must be "representative" to the satisfaction of the EPA
    Office of Solid Waste such that the data resulting from the treatment  test can
    be submitted in a delisting petition, as noted below.   Variables for the test
    will Include soil feed rates, EDTA concentration, recycle system data, and other
    system operating parameters.  Measurements will Include Initial  lead concen-
    tration, final lead concentration, lead concentration  in  produced sludge,  feed
    rates, EDTA recycle effectiveness (EDTA use rate), and other  chemical  use  rates.
    Also, the number and training levels of the personnel  needed  for operating the
    process will  be determined.  The goal of these tests  is to Identify the most
    cost-effective treatment  conditions, requiring the minimum personnel,  at the
   .greatest possible capacity.
                                      178
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6.  After the tests, remaining soil  must be disposed of.  Some soils,  by  design,
    will not have been adequately treated and may have to be recycled to reach the
    design treatment level. There is always an outside possibility  that  all  of the
    soil will fall short of the treatment goal. These soils  will  be either trans-
    ported back to Bettendorf or sent to a hazardous waste disposal facility.
    Specific arrangements for the disposition of untreated/inadequately  treated
    soils must be made and agreed to by all principals prior to the transportation
    of the contaminated soils from Bettendorf to Edison,  and should be addressed  in
    the Plan for Phase III prepared  during Phase II.

7.  The equipment and test area must be decontaminated and the decontaminating
    solutions disposed of in a suitable manner as noted above for the soils.

8.  The test equipment must be disassembled and returned  to  storage or prepared for
    shipment to the field.


Concurrent with these tests, necessary permitting documentation associated with
Phase IV (and also appropriate to a  full field activiation using the  same process)
will be prepared.  As noted above, this will  include State and Federal requirements
and will probably include a delisting petition.  Data from the pilot-scale tests
will be used in the delisting petition to demonstrate that the treated soil  is
"nonhazardous" to the satisfaction of OSW.

Additionally, during and following these tests, preliminary  planning  will be con-
ducted for a field activation using  the EPA prototype Soils  Washing System.   This
planning will include all of the necessary logistical elements and  preparations
for operating the system in the field for an  extended period.  However,  because
this planning is a significant effort, a detailed plan will  not be  conducted
until  authorization to proceed with  Phase IV  is received.


Time Frame ...  3-6 Months from authorization to proceed

Cost 	  $300,000 - $700,000

Product 	  Interim report providing data, detailed estimates and preliminary
                plans for Phase IV

Note:   This interim report will contain sufficient data for  the specification of  a
       field operation by sources other than  ORD.  Therefore, Phase IV is designed
     •  to be an optional phase.
                                        179
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 Phase IV      Field  Demonstration


 The objective of  this  phase will be to determine field-related variations to the
 unit  costs,  lead  removal  performance and system reliability determined during the
 pilot scale  tests in Phase III.  The resulting information from this phase would
 be  used by Region VII  to  specify contracted cleanup efforts using commercially
 available equipment and personnel.

 Pilot scale  tests conducted during Phase III will be done under carefully con-
 trolled conditions  at  Edison, NJ, with a maximum of nearby shop and logistical
 support to help overcome  unanticipated difficulties.  Running changes can be made
 relatively easily and  cheaply because of the availability of extra personnel when
 needed and a strong base  of equipment testing capabilities.  Field operations, by
 comparison,  require substantial advance planning to assure that the operation pro-
 ceeds smoothly from mobilization through startup and into reliable continuous
 operations.   Omissions or errors in the planning process, as well as uncontrolla-
 ble variations such as severe weather, quickly translate into lost time and extra
 costs. Field tests are,  therefore, expensive, demand the most from advance plan-
 ning  and preparations, and require contingencies in the planning process relative
 to  both time and  costs.   However, once these advance planning activities have
 been  completed, the equipment has been set up and is operating smoothly, continu-
 ing field operations are  not especially difficult.

 RGB has had  twelve years  of field experience with operations utilizing complex
 cleanup equipment for hazardous material spills and waste sites.  These experi-
 ences have highlighted the need for careful, sequential advance planning and ade-
 quate shakedown and testing prior to committing to expensive field activities.


 This  phase would  proceed  in approximately the following manner:

 o   Meet with  Region VII to define goals, objectives, financing arrangements, oper-
    ating location(s) permitting responsibilities; division of activities between
    ORD and Region VII (e.g., Region would handle legal  and public affairs, ORD
    would execute technical aspects of project; Regional analytical support could
    be very helpful if available; authority to access site critical).  Note that
    operating  location may or may not be on the site to be cleaned up—depending
    upon many  factors.

 o  Define with Region VII a project management plan, including roles and responsi-
    bilities of Regional, ORD, and contractor individuals on the project.  Define
    lines of communication and patterns of routine reporting.  This is critical 1
    *
 o  Define with Region VII a desirable scope of operation, e.g., materials to be
   treated during demonstration, duration of operation, operating period per day
    (8, 10, 12, or 24 hours).

o  Define with Region VII means to excavate and transport (if needed) contaminated
   soils to treatment site and treated soils from treatment site to point of origin.
                                       180
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o  Define with State of Iowa, as needed, permitting requirements and responsi-
   bilities.  (This will be done preliminarily during Phase III but must be
   continued during Phase IV.)

o  Prepare detailed site-installation design(s), with provision for security,
   power, wastewater discharge, water supply, storage of equipment and chemicals,
   personnel support trailers or other quarters, etc.

o  Prepare detailed logistical support list of all  necessary equipment to be
   taken to the field, including spare parts and necessary tools and trouble-
   shooting apparatus.

o  Arrange for necessary analytical support, either through the Region, a local
   laboratory, or an on-site mobile laboratory, as  appropriate.  Prepare a de-
   tailed Sampling and Analysis Plan and a Quality  Assurance Project Plan.

o  Arrange for suitable ultimate disposal (hazardous landfill, smelter) of con-
   centrated lead products.

o  Arrange for chemical and other expendable supplies.

o  Prepare detailed project plans, including schedule and budget, with arrange-
   ments for routine reporting to compare planned progress and expenditures
   against actual progress and expenditures, and management "checkpoints."

o  Mobilize operating crews, with appropriate safety, environmental, and operator
   training (may be subcontractor personnel, particularly if 24 hr/day, 7 day/
   week operations are needed and multiple crews with rotation are used).  Conduct
   training on equipment set up at Edison or at Bettendorf.

o  Mobilize equipment including all necessary arrangements for transportation,
   setup, and on-site shakedown.

o  Execute operation, in accordance with detailed operating plans.

o  Demobilize and decontaminate equipment and restore operating site(s) to a con-
   dition suitable to owners (criteria for suitability to be agreed to prior to
   mobilizing personnel and equipment at site).  Return equipment to Edison and
   perform restoration maintenance, as needed.


The scope of this Phase can be highly variable.  It is desirable to clean up a
smaVl site or sites to demonstrate the suitability  of the process; however, it
is not desirable to use the ORD equipment for extended operations for the pur-
pose of cleaning up many sites.  The most appropriate scope will involve a
short proof-of-technology demonstration to obtain specifications and cost esti-
mates such that the actual cleanup involving many "hot spots" could be executed
by a cleanup contractor.
                                       181
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Time Frame
Planning & preparations:  1-6 months (depending on permits)
                Field Demonstration:
                Report:
                          30-90 days of operations (including
                          some "down time" for maintenance, etc.)

                          Draft delivered 90 days after completion
                          of field operation; final  report to
                          management after additional  90 days.
Cost 	  $500,000 - $2,000,000:
                          (depending on hours/day of operation
                          and degree of acceleration of the
                          schedule)
Products
Final Report, consolidating the work of all  phases,  and providing
specifications, cost estimates, and activity schedules  suitable  for
use by Region VII 1n procuring contracted  services for  a full-scale
cleanup using EDTA-extraction technology.

Technical  paper, providing synopsis of Final  Report.
                                       182
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   SECOND INTERNATIONAL SYMPOSIUM ON
   METALS SPECIATION, SEPARATION AND RECOVERY	

                               May 14-19,1989
                                  Rome, Italy

                         RESULTS OF BENCH-SCALE RESEARCH EFFORTS
                                       TO  WASH CONTAMINATED SOILS
                                   AT  BATTERY-RECYCLING FACILITIES
 Judy L. Hessling
 PEI Associates, Inc., Cincinnati, Ohio

 M. Pat Esposito
 Brack, Hartman & Esposito, Inc., Cincinnati, Ohio

 Richard P. Traver, P.E.
 U.S. Environmental Protection Agency, Edison, New Jersey

 Richard H. Snow, Ph.D.
 IIT Research Institute, Chicago, Illinois
 INTRODUCTION AND BACKGROUND

       Under U.S. laws such as CERCLA* and the National Contingency Plan
 that implements it, response actions at hazardous waste sites must reduce the threat
 of uncontrolled wastes.  Until recently, this has often meant the excavation or
 removal of wastes from uncontrolled situations and the movement of those wastes
 to permitted landfills. In 1984, Congress clearly showed its intent to minimize the
 volume of such wastes going to permitted landfills by passing the Hazardous and
 Solid Waste Act (HSWA) amendments.  One effect of this legislation has been the
 mandate of a major change in cleanup procedures to encourage the application of
 waste treatment technologies prior to disposal

       The policy of the U. S. Environmental Protection Agency's (USEPA) Office
 of Solid Waste and Emergency Response, which is responsible for implementing
 the 1984 HSWA amendments, is to discourage containment-based  disposal of
 CERCLA wastes and to encourage the use of technologies which eliminate or reduce
 the hazardous characteristics of the  waste. On-site treatment technologies that
 destroy or reduce  contaminant levels achieve more positive control  than
 containment technologies.  Off-site disposal in  landfills will probably continue to
 be allowed on a more limited basis in the future, but only when destruction or
 treatment technologies are not available for reducing the hazards of the waste prior
 to disposal.  As landfill  space becomes more limited and  expensive,  and  as
-transportation becomes more stringently  controlled, on-site waste treatment
"technologies  will   become  more  desireable—if  they are technologically
 demonstrated, environmentally safe, and affordable.

       Soil and debris contaminated by lead  (Pb) and other heavy metals are
 problems at many hazardous waste sites where metal recycling and reclamation
 activities have been conducted.  Typical examples are sites where used batteries are
 collected and processed by various cracking and secondary smelting operations.

 ^Comprehensive Environmental Response, Compensation, and Liability Act
                                     183
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        Piles  of spent battery casings as well as slag and dust from furnace
 operations are often found at such sites.  Soil contamination at these sites can
 typically reach levels in the hundreds and thousands of parts per million (mg/kg)
 metals.  At some sites, Pb levels as high as 10% in soil have been found.  Twenty-
 three battery recycling sites currently appear on the United States' priority listing
 of contaminated sites requiring cleanup under CERCLA. Many others are known
 to exist which are not yet part of the priority list for remediation.

        Soil washing can be an effective means of either cleansing the soil  or
 reducing the volume of contaminated solids that ultimately must be treated  or
 disposed. It  has been under intense investigation by the USEPA for the past ten
 years.  Recently, the USEPA and the Bureau of Mines  established a Memo  of
 Understanding for evaluating  specific ore  enrichment/extraction technologies
 with potential application to  lead battery hazardous waste sites.   Specific
 technologies centering on the  use  of fluosilicic  acid, electrowinning,  and
 recovery/recycle of lead-enriched soil fractions for reprocessing in secondary lead
 smelters are being evaluated and demonstrated.

        Recently, a series of soil-washing studies  sponsored by the USEPA's Risk
 Reduction Engineering Laboratory was completed through the collaborative efforts
 of a group of scientists from various research organizations.  In these studies, the
 investigators attempted to wash samples of soil from six battery-recycling sites  in
 the United States as well as a surrogate synthetic soil spiked with lead and other
 metals.  The soils were subjected to a rigorous bench-scale  washing cycle using
 either tap water or tap  water plus additives (surfactant or chelate).  After a 30-
 minute contact period, the soils were separated from the wash water and rinsed.
 The washed soil was separated into three distinct size fractions during the rinsing
 operations to study the partitioning of metals relative to particle size.

        This paper presents a partial analysis of the results of these bench-scale
 studies. It includes a discussion of the background operations at each site that were
 responsible for the soil contamination problems,  a description of the geophysical
 properties of the soil and contaminant levels at  each site, an explanation of the
 experimental bench-scale procedures followed, and a presentation  of the findings
 relative to total lead levels in the soils before  and  after treatment Results of tests
 performed on EPA's synthetic soil matrix (referred to as SSM) are also presented
 and compared with the results for the actual site soils.  The project included testing
 the soils for leachable Pb, but the analytical data from this portion of the study are
 not yet available and therefore could not be presented at this time. The leachate test
 results could significantly alter the initial  findings and  conclusions offered  in
 this report.
 SUMMARY OF FINDINGS
•»»•
        The study results available at this time indicate that soils from battery-
 recycling operations in general are not highly responsive to soil washing under the
 types of contact and washing conditions included in these experiments. Total Pb
 contamination was  virtually unchanged in  several of the soil residues after
 treatment, separation, and rinsing.  At best, some portions of some soils showed
                                        181
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reductions on the order of 50 to 80 percent in total Pb concentrations compared with
the untreated soils; however, even with such reductions, the total amount of lead
remaining in  the residues was often still very high (hundreds to thousands of
mg/kg).  Generally, plain tap water was least effective as a washing medium. The
addition of a  surfactant to  the water produced marginal improvement, and the
addition of a chelate showed even further promise as a washing aid, based on the
increased concentrations of Pb in the spent wash waters.

       These  results are markedly different from those obtained when washing
the synthetic  soil.  Lead concentrations, which were very high in the soil before
treatment (>14,000 mg/kg), were substantially reduced after treatment, especially
when a chelate was added to the wash water. Apparently, the Pb in the freshly
spiked soil had been afforded little opportunity to weather and mineralize and was
therefore more easily removed from the soil by this technology.
SITE PROFILES

       The six sites that are the focus of this study are among the United States'
highest priority sites for cleanup under CERCLA. As shown in Figure 1, these sites
represent a broad range  of geographic locations, climatological conditions,  and
native soil types. A variety of process operations and waste disposal practices over
several years contributed to soil contamination at these sites.

Sti&A

       Automotive battery-recycling and secondary lead smelting and refining
operations at this 46-acre site in rural northeastern United States began in 1972 and
continued for 12 years. Recycling operations consisted of cracking the batteries,
draining the acid, removing the lead plates, and crushing the casings. The scrap
lead was then smelted in a blast furnace or (later) rotary kiln and refined to
produce soft lead or antimonial lead. Furnace gases  passed through an 18-cell
baghouse for particulate  removal.   Lead-bearing wastes, including the crushed
battery casings (rubber and plastic), blast furnace and kiln slag,  and baghouse
dust, were piled, buried, or landfilled on site. In 1980, the owner entered into an
Administrative Consent Order to remediate soil and ground-water contamination
at the site; and in 1983, the site was listed on the Superfund National Priorities List
(NPL).  The  interim  remedial investi-gation/feasibility study report (January
1989) indicates that soils in the plant area contain up to 12,700 mg/kg lead. Current
activities on site are associated with closure and post-closure  care of the landfill.

SiteB

       Lead-acid batteries were recycled at this 4.5-acre site in mideastern United
States from the early 1970's until 1985. Lead and lead compounds were removed
•from the batteries and shipped offsite for processing.  Acid was drained into onsite
lagoons, and broken  battery  casings  (primarily  plastic)  were shredded  and
stockpiled on site. During a 1986 removal action, acidic liquids were pumped from
the lagoons, neutralized, and discharged to a storm sewer; sludge was excavated,
blended with hydrated lime, and returned to the lagoon; and surface soils were
disked with lime to a depth of 2 ft. An 800-sq-ft mound of soil mixed with battery
                                        185
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casings remains on the site.  Lead concentrations as high as 67,700 rag/kg have
been measured in the soil; elevated levels of arsenic, cadmium, copper, nickel, and
zinc have also been detected.

SiteC

       From 1972 to 1986, a lead-acid battery reclamation facility was operated on
this 17.4-acre site in a southern Atlantic State. Lead and lead oxide were removed
from discarded batteries and shipped offsite for smelting.  Initially, rubber battery
casings were crushed and used as fill and paving near the processing area;
several tons of this fill material was later excavated for recovery of additional
lead.   Plastic casings, which eventually replaced rubber in the manufacture of
batteries, were crushed and sold to a recycler. Until 1981, sulfuric acid from the
discarded batteries was treated with lime (calcium oxide) or ammonia and
discharged to a 22-acre unlined holding pond; in later years, the wastewater was
neutralized and discharged under permit to a publicly owned treatment works
(POTW).  Also, some waste acid was marketed to  the phosphate industry as a
processing agent. Lead concentrations in the pond sediments are generally below
500 mg/kg, but they range up to 40,000 rag/kg in the process area soils.

SiteD

       This Pacific Northwest site covers approximately 60 acres in a heavily
industrialized area.  Battery recycling, secondary lead smelting and  refining,
zinc alloying and casting, and cable sweating operations began in 1949; lead oxide
production began in 1965. Over the 30-year operating life of the facility, 86,900 tons
of waste battery casings (rubber and plastic), 11,800 tons of matte (composed of iron
and lead sulfides), and 6.57 million gallons of sulfuric acid were disposed of on the
site and adjacent property. Approximately 98 percent of the battery  casings are
buried below the surface, where they are in direct contact with the ground water.
Concentrations of lead in the battery-casing wastes range up to  190,000 rag/kg;
concentrations of lead in the surrounding surface soils range up to 20,000 mg/kg.
An  estimated 22,000 cu yd of soil requires treatment or removal. The site was listed
on the NPL in 1983.

SiteE

       This site in southeastern United States consists of several parcels of land
where  lead-bearing  wastes from  the  main lead-acid battery-recycling and
secondary  smelting facility were deposited  as fill.  Operations at the facility
involved battery cracking and separation of lead-bearing solids followed by lead
smelting,  refining, alloying,  and casting.  Waste  acid and  rubber and plastic
chips from the battery-cracking operation were  shipped offsite for recycling or
disposal.  Slag from  the smelting/refining operation was accumulated in  waste
piles on site. In 1986, the facility began adding calcium sulfate sludge  to the blast
furnace slag to immobilize the lead  and then disposing  of the fixed  slag in  the
county  landfill.  Soil samples collected from various locations during the 1987
remedial investigation indicate that lead contamination averages more than 1000
mg/kg over most of the site and exceeds 30,000 mg/kg in some areas.
                                        186
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SiteF

       From 1979 to 1981, a nickel-cadmium battery-recycling facility operated on
this 6.7-acre site in south-central United States. The batteries were charged to one
of four furnaces; and cadmium, which was driven off from the process as cadmium
oxide, was condensed from the exhaust gases and poured into molds.  The molds
were then resmelted in a ball furnace, and the cadmium was recast into 1-1/4-lb
balls for shipment to various plating  operations.  Furnace gases were ducted
through a manifold to a cyclone separator and fabric filter before being discharged
to the atmosphere. Cadmium emissions from the fabric filter, along with improper
storage and  handling of process materials and  residues, have contributed to
widespread soil contamination at the site.  Prior to an immediate removal action
in 1983, cadmium concentrations in the soil ranged up to  9000 mg/kg; although
most of the contaminated materials and debris have now been removed, cadmium
concentrations still range between 1000 and 5000 mg/kg over the south portion of the
site. Concern over possible exposure of neighboring residents to cadmium from
fugitive dust emissions prompted capping of the unpaved areas of the site. More
recent sampling has shown that the soil is also contaminated with lead, copper,  and
nickel.

SSM

       In 1986,  the EPA developed a Synthetic Soil Matrix (SSM) for purposes of
evaluating alternative technologies for treating hazardous wastes.  The soil, which
is composed of a mixture of gravel, sand, silt, clay,  and topsoil, was spiked with 17
chemical contaminants (volatile organics,  semivolatile organics, and metals) at
concentrations typically occurring at Superfund sites. The target concentration for
lead was 14,000 mg/kg. The spiked soil was prepared in 500-lb batches by blending
an insoluble lead salt (PbS04*PbO) and the other contaminants with the clean soil
in a 15-cu-ft mortar mixer. The SSM was stored in 5-gal steel pails or 55-gal drums
for subsequent testing and thus was never exposed to field conditions.
SOIL CHARACTERIZATION

       Samples of the raw soil from  each of the  six sites and  SSM were
characterized  for  physical and  chemical properties, including  grain  size
distribution, moisture content, pH, cation exchange capacity (CEC), humic acid,
total organic carbon (TOO, and lead (total and leachable). These characterization
data are  summarized in Table 1.   The predominant clay minerals and  lead
species, as determined by X-ray diffraction, are also indicated.  Soils from Sites C,
D, and E have a high percentage of sand and gravel, whereas soils from Sites A, B,
and F and the SSM have a relatively high percentage of silt and clay. The moisture
content of all the soils ranges from 2 to 20 percent.  Soil pH is around neutral for
Sites A, C, D, E, and F and slightly alkaline for Site B and the SSM. The CEC for
soils from the six sites is below 40 meq/100 g, in contrast to that for the SSM, which is
above 130 meq/100 g. Humic acid content for all soils measured is low (1 percent or
less).  Soils from Sites B, D, and E have a low TOC, and soils from Sites A, C, and F
and the SSM have a high TOC. The total lead concentration in the soils ranges
                                      187
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from a few hundred parts per million (ppm) for Site F to a few thousand ppm for
Sites C and E to tens of thousand ppm for Sites A, B, and D and the SSM. Leachable
lead concentrations are  generally two orders of magnitude lower than total lead
concentrations. The predominant lead species in the naturally occurring soils are
cerussite (Sites A and C), hydrocerussite (Site B), hillite (Site E), and anglesite and
plattnerite (Site D); lead sulfate and lead oxide were used to spike the synthetic soil.
EXPERIMENTAL SOIL-WASHING PROCEDURES

       The soil-washing procedures followed during this testing and evaluation
program were  based on a set of four assumptions that underlie  the volume-
reduction approach  to  washing contaminated  soils.  The assumptions are as
follows:

          •A significant fraction of the contaminants in  soil are either
          physically or chemically bound to the silt-  and clay-sized particles of
          the soil.

          •The silt and clay are attached to the sand and  gravel by physical
          processes such as compaction or adhesion.

          •Physical  washing (e.g., scrubbing) of the sand and gravel fractions
          will effectively remove the fine silt and clay materials.

          •The contaminants will be removed to the same extent that the silt and
          clay are separated from the sand and gravel.  Increasing the efficiency
          of the washing process will directly increase the removal rate.

       In each experiment, a 500-gram sample of soil was mixed with 5000 ml of
wash water (10:1 wash water-to-soil ratio) in a 10-liter glass jar and agitated on a
reciprocating shaker for 30 minutes.  The soil was  then  separated from the wash
water by wet sieving and filtering; this operation simultaneously separated the soil
into three size fractions:

       >2-mm  fraction            Coarse sand and gravel      No. 10 screen

       0.25- to 2-mm fraction       Fine sand                  No. 60 screen

       <0.25-mm  fraction          Silt and clay               Filtered (on
                                                             0.45u filter
                                                             paper) from the
                                                             wash water
                                                             that passed
                                                             both screens

       The solids  retained on each screen were  rinsed with 2000 ml of tap water
and subjected to a mechanical (vibratory) dewatering device for 10 minutes.  The
residues and the  spent wash waters were then submitted to an EPA-approved
laboratory for contaminant analysis following the methods of SW-846.
                                        188
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       Duplicate samples  of each  soil were washed by this method, and the
analytical results for the two sample sets were averaged.  The duplicate analytical
results did not always match well, especially  for samples  with relatively high
levels of lead contamination. This variability was expected, however, and must be
tolerated under real field conditions where soil contamination often varies widely
within small areas.

       Three wash solutions were studied:

              1) Tap water, pH 7

              2) Tap water plus anionic surfactant (0.5 percent solution)

              3) Tap water plus tetrasodium ethylenediamine tetraacetate
                 (NajEDTA) 3:1 molar ratio EDTA to toxic metals), pH 7-8

Figure 2 presents a schematic of the  procedure followed for all experiments.


RESULTS AND DISCUSSION

       Table 2 presents the analytical results for total Pb found in the spent wash
waters.  Little or no Pb was found in  any of the tap-water wash solutions, which
indicates that tap water alone was unable to dissolve the lead in the soil. The
addition of the surfactant increased the amount of lead in the spent wash water
about 100-fold, and the addition of the chelate increased the lead solubilization even
more.  In  some cases, for example soils from Sites A, B, and E and the synthetic
soil, the chelate increased the amount of lead in the spent wash water about 1000-fold
over the plain tap-water  wash.   These data indicate that most  of the lead
contamination in the battery-recycling-site soils is insoluble in water.  They also
indicate that surfactants and chelates such as EDTA offer good potential as soil
washing additives for enhancing the  removal of lead and possibly other metals
from contaminated soils and solid debris.

       Analytical results for the soil residues from the experiments are presented
in Tables 3-5. Average values for each soil size fraction recovered after washing
are shown, as well as the average total contamination levels in the whole soils prior
to treatment.  Overall, these data are not encouraging.  No clear pattern has been
identified, other than for most of the soils, the  residuals were  still  highly
contaminated with Pb, even after treatment  with the  chelate.  Two obvious
exceptions to this generalization are the soil from Site F and the SSM.  Both soils
had similar  grain  size distributions and both had a clay content that was
dominated by kaolinite. The treated fractions of all sizes for these two soils were
the cleanest (had the lowest residual  Pb levels) of the lot when washed with chelate.

       The data collected in this study have not been  statistically evaluated for
trends. They have been checked for quality assurance purposes, however,  and no
deficiencies or abnormalities were noted.  Visual observation of the data set as a
whole has revealed  no apparent trend in soil or contaminant behavior relative to
the type of Pb contamination (predominant lead  species), type of predominant clay
                                       189
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(percent or mineralogy), or particle size distribution. Overall, the results of this
research strongly suggest that the applicability of soil washing to soils at these types
of sites must be determined on a case-by-case basis.
CONCLUSIONS

       It appears that soils from battery-recycling sites that have undergone years
of neglect and weathering may not readily respond to soil washing as a remedial
treatment technology. Also, Pb probably cannot be physically separated from the
soil or concentrated into a smaller volume by particle size separation; it certainly
did not partition cleanly into any of the three particle size ranges evaluated in this
study.

       Future efforts to interpret the results of this research effort will  include
results of leachate tests on the residues. These data were not yet complete at the time
of this writing and unfortunately could not be included in  this discussion  of
results.  Initial teachability tests on the untreated soils (presented  in Table  1)
showed that all released relatively small amounts of Pb (compared with  total  lead
levels) when exposed the the mild acid extraction  medium of EPA's established
leaching procedures. Nevertheless, the leachate values were all substantially
higher than available U.S. standards permit (5 mg/1 Pb maximum).   It  will be
interesting to see if the leachates developed from the treated soils contain reduced
levels of Pb; if this is the case, it may improve the picture for soil washing as it will
indicate that this technology can be used to remove the most soluble portion of the Pb,
thus removing the most important negative environmental impact associated with
this type of soil contamination, which is toxic metal mobility.
ACKNOWLEDGMENTS

       This research was funded in its entirety by the USEPA's Office of Research
and Development,  Risk Reduction Engineering Laboratory.  Mr.  Richard P.
Traver was the USEPA Project Officer in charge of the work.  The authors wish to
thank Mr. Traver for his guidance, encouragement, and timely review of the data
throughout the research effort

       The Synthetic Soil Matrix which was included in this report is available for
other soil treatability research efforts.  For further information on its composition,
availability,  and response to other treatment technogies, please contact:

  Mr.  Ray  Frederick
  U.S.  Environmental Protection Agency
  Risk Reduction  Engineering Laboratory
  Releases Control  Branch
  2890 Woodbridge Ave.
  Edison,  New Jersey   03837
  (908) 321-6627
Keywords:  Lead, Soil Treatment, Soil Washing, Volume Reduction, Hazardous Waste
                                        190
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                TABLE 1. CHARACTERIZATION OF SOILS FROM BATTERY-RECYCLING SITES
Parflfflatar
Grain size distribution
Sand and gravel, wt %
Silt, wt %
Clay, wl %
Predominant day species
Moisture content, %
PH.S.U.
Cation exchange capacity,
meo/100 g
Humte add, *
Total organic carbon.
mg/kg
Lead (total), mg/kg
Lead (teachable), mg/llterb
Predominant toad species
film A
69
17
14
Illlte/
Kaollnlte
7.2
6.16
36.6
0.34
16,000
67,150
300
PbCQ3
SHeB
55
31
14
Illlte/
smectite
17.5
9.34
36.6
0.04
7.016
75,850
418
PB3(C03)2-
(OH)2
SltflC
87
6
7
Smectite
6.5
7.24
40.2
0.76
14,150
3,230
65.5
PbCOa
SllaD
91
5
4
Smectite/
Illlie
2.4
6.60
23.6
1.21
6.555
27,160
146
PbSOV
PbOj
SHflE
90
8
2
Kaollnlte
8.8
6.31
6.2
NA«
3,588
3,945
196
PD4S04-
(C03)2(OH)2
SilflF
63
20
17
Kaollnlle/
smetlle
10.7
6.55
13.4
N\
14,500
302
N\
r*V
SSM-III
59
28
12
Kaollnlle/
bentonlte
19.5
8.5
133
m
32.000
14,318
19.9°
PbSOV
PbO
SNA- not analyzed.                                                              Kaollnlte-AlaSlaOs (OH)«
&As measured by the Extraction Procedure (EP) Toxldty test, unless otherwise Indicated.      Smecllte.Na-Ca.AI-SI-0-H
CAS measured by the Toxldty Characteristic Leaching Procedure (TCLP).                   llllie.K-AI.SI.O-H
                                   Figure 1.  Locations of battery-recycling sites.
                                                       191
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W 1 •» '
. 	 . I | «v« •
f\ 	 	 	 •rlV tSi-l--
\^J ""* |-=— | "• V '
«— , T ,
Qtttflt
von*
5, _*. £* 	 fc-xzz/* — *-H *>**
— ^ 	 KMI LJ
*" \ / "" 	 »^zz^-r-*-n»«"*
—•II1 	 ' KM.I A '-J
1 1 M-A1C
•"•• 	 I 1
^53f ^^
1 PRUMM f ncMUM
rn"11111 iT"1*
IT — *"!_ 1 	
turn
Figure 2. Bench-scale soil washing procedure.
TABLE 2. TOTAL LEAD CONTENT OF SPENT WASH WATERS
ing/liter
Site Water
Wash
A 0.79
B 024
C 0.32
D 0.82
E 0.43
F <0.06
SSM Not Analyzed
Surfactant Chelate
Wash Wash
164 1,255
1&6 912
38.4 73.5
127 324
Not Analyzed 456
Not Analyzed 5.4
Not Analyzed 12.500
192
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TABLES. TOTAL LEAD CONTENT OF TREATED SOIL
RECOVERED ON NUMBER 10 SCREEN (> 2 MM) mg/kg
Site
A
B
C
D
E
F
SSM

Site
A
B
C
D
E
F
SSM
Whole soil untreated
67460
76350
3,230
27450
6494
210
14.318
Water Wash
163400
60460
893
31350
6,487
42
122
Surfactant Wash
98400
66300
1380
25,610
Not Analyzed
Not Analyzed
Not Analyzed
ChelateWash
119,050
164,200
886
8366
1,081
30
98
TABLE 4. TOTAL LEAD CONTENT OF TREATED SOIL
RECOVERED ON NUMBER 60 SCREEN (0.25-2mm) mg/kg
Whole soil untreated
67460
76360
3,230
27460
5^14
210
14.318
Water Wash
22300
62£00
2460
12300
2,020
312
491
Surfactant Wash
32,000
49,670
1.766
10,960
Not Analyzed
Not Analyzed
Not Analyzed
Chelate Wash
24,550
57350
2340
8,670
1316
408
171
               193
-------
       TABLE 6. TOTAL LEAD CONTENT OP TREATED SOIL
PASSING BOTH NUMBER 10 AND NUMBER 60 SCREEN (<0.25mm) mg/kg
Site
A
B
C
D
E
P
SSM
Whole soil untreated
67,160
76350
3,230
27460
6,194
210
14.318
Water Wash
14,650
49,500
2£49
41/100
13,698
111
30.600
Surfactant Wash
36,460
62400
2,646
42,700
Not Analyzed
Not Analyzed
Not Anal vied
Chelate Wash
41,250
24470
3.995
16^50
4,693
73
1.470
-------
                                    EPA/540/2-88/002
                                      August 1988
    Technological Approaches to the

Cleanup of Radiologically Contaminated
             Superfund Sites
            U.S. Environmental Protection Agency
               Washington, D.C. 20460
                     195
-------
                                       Executive Summary
Introduction

This document identifies potential  technologies that
possibly can be applied in the control and remediation
of radioactive contamination  at Superfund sites. This
report  provides a  discussion of  the technologies; it
does not give a detailed critical  evaluation  of  them.
The report does  not  include in-depth analyses that
would be needed  to determine the applicability of any
of these technologies at a particular site.

The report only addresses treatment and disposal  of
radiologically contaminated soils, and radon control. It
does not  address,  for  example,  remediation  of
radiologically contaminated buildings. The report also
does  not  address  treatment  of  radiologically
contaminated ground  water,  which is  of concern  at
some Superfund sites.

The radioactive materials at many Superfund sites are
by-products  of  uranium,   thorium,  and  radium
processing in the  form of  tailings,  contaminated
buildings and equipment, and stream sediments.

The primary public health threats from the radioactive
materials are through  inhalation of  radon  and  radon
progeny, external  whole  body exposure to  gamma
radiation, and ingestion of radionuclides through food
and water.  Radon  and   radon  progeny  are
continuously produced  through  the decay  and
decomposition  of uranium,  thorium, and radium.
These  hazards will  persist  throughout the  entire
decay  time if no  remedial  action  is  taken.  These
hazards could include the increased risk of cancers in
the exposed whole body and may  also increase the
risk  of  genetic damage that  may continue to cause
inheritable defects in future generations.

It should be noted that the  radioactive contaminants
are  not  altered  or destroyed  by  treatment
technologies.  The  volume of contaminated material
may be  reduced,  but the   concentration  of the
contaminants will  be  much  higher in the  reduced
volume. Some type of containment and/or  burial  is
the only ultimate remedy for  materials contaminated
at levels above those considered safe for exposure.

Table A on the following page shows the state of the
art  of the various disposal,  on-site treatment, radon
control, chemical extraction, physical  separation, and
combined physical separation and chemical extraction
technologies that are discussed in this  report. Since
none  of the  chemical extraction  and  physical
separation  technologies has  been used  in  a  site
remediation situation,  their  application  must  be
approached cautiously.

Significant research and development  activities would
be  necessary prior to full-scale mobilization for site
cleanup. The same  holds  true for solidification or
stabilization  processes.  Only excavation  and land
encapsulation  have  been  used  to remediate
radiologically contaminated sites; ocean disposal has
been used  for disposal  of  low level radioactive
wastes.

Remediation Sites

Twenty sites that contain  man-made radioactive
wastes are  on or  are proposed for inclusion on the
National Priorities List (NPL). These Superfund sites
are described briefly in Appendix B of this document.
(Information  provided is accurate as  of  December
1987.)  The sites  contain  tailings  piles and
redistributed tailings,  solid waste  landfills, hazardous
waste landfills, fabrication plants and laboratories, and
contaminated ground water. Remedial  investigation
and  feasibility studies (RI/FS) have been completed
on  eight sites and  are underway  on  seven sites.
Remediation  at  none  of these  sites has been
completed.   However,  the  Department of  Energy
(DOE)  has  completed  remedial actions  at  vicinity
properties associated  with DOE NPL sites.

The  DOE cleanup projects, which also are  described
in  Appendix B,  mainly  stem  from DOE's  inherited
responsibilities  in  the  area of  nuclear  materials
production. DOE has four major cleanup  projects:

    (1) Formerly Utilized  Sites  Remedial  Action
       Project (FUSRAP) - 29 sites;
    (2) Uranium Mill Tailings Remedial Action Project
       (UMTRAP) -  24  sites;
    (3) Grand Junction Remedial Action Project
       (GJRAP) - 1  site; and
    (4) Surplus  Facilities  Management  Program
       (SFMP) - 17  sites.
                                                  196
-------
Table A. State of the Art of Remediation Technologies
                                                                Field
Technology
On-site Disposal
Capping
Vertical barriers
Off -site Disposal
Land encapsulation
Land spreading
Underground mine disposal
Ocean disposal
On-site Treatment
Stabilization or solidification
Vitrification
Radon Control
In homes
- ESP
Area) control
Chemical Extraction
Witt) water
With inorganic salts
With mineral acid
With comptexing agents
Physical Separation
Screening
Classification
Gravity concentration
Flotation
Combined physical separation
and chemical extraction
Soil washing and physical
separation
Separation and chemical
extraction
Demonstration
Bench Pilot with
Laboratory Scale Scale Radioactive
Testing Testing Testing Material

X


X
X
X
X
X X
X X

X X
X X
X X
X X
x xxx (from ores)
x xxx (from ores)

x x (from ores)
x x (from ores)
x x (from ores)
x xx (from ores)

x x
x
Radiologically
Contaminated
Site
Remediation Remarks

x


x
Land spreading of low-level radium sludge
from drinking water is an allowed policy in
Illinois
DOE currently working on mined repository
for radioactive waste
Stringent regulations for radioactive waste
Proposed by DOE for low-level radioactive
waste
Field testing by ORNL
x As a temporary and interim measure



(
Used in extraction of radium, thorium, and/or
uranium
Used in extraction of uranium

Used in extraction of radium, thorium, and/or
uranium
Used in extraction of radium, thorium, and/or
uranium
Used in extraction of radium, thorium, and/or
uranium
Used in extraction of radium, thorium, and/or
uranium

Pilot-plant development and testing needed
v lor radioactive wastes
Various portions of the process have been
developed for extraction of uranium from
     Separation, washing,  and
     extraction
ores. Pilot-plant testing and development
needed for radioactive waste
Significant bench-scale and pilot-plant
testing needed for radioactive waste
                                                             197
-------
 Current DOE  projects also involve the  cleanup  of
 thousands  of vicinity properties,  about  4000  in
 GJRAP alone. The  Grand Junction  Remedial Action
 Project has  excavated  and moved  contaminated
 material to an interim storage site from approximately
 700  vicinity sites  and  is  currently  evaluating
 alternatives for remediation of the interim storage site.
 To date, seven sites administrated by DOE under the
 FUSRAP project have been remediated. Three of the
 FUSRAP sites  are  also  on the NPL.  The  SFMP
 includes over 30 currently active projects.  Two of the
 SFMP sites are on the NPL.

 In addition, DOE's Office of Defense  Programs (OOP)
 has a  program similar to SFMP for its sites. OOP
 conducts selected remedial decontamination activities
 as required at facilities under their jurisdiction.

 In  most  remedial actions  conducted to date, the
 radioactively contaminated material  has been
 excavated and  contained  in either permanent or
 temporary  above-ground containment facilities.
 These  facilities  have been  designed  to include
 perimeter air  monitoring, surface  water  runoff
 collection and  containment features,  and  ground
 water monitoring devices.

 All methods used to accomplish  remedial action on a
 site contaminated with radionuclides  will result in
 waste  materials  that require disposal or storage.  The
 final disposal  of these waste materials is the single
 largest problem in remedial action.

 Some of the Superfund sites contain  various types of
 hazardous wastes,  and the radioactive portion may
 pose a  relatively minor problem. The  presence of
 other   hazardous  materials   may  complicate
 remediation  of the  radioactive portion of  the waste
 and vice-versa.

 Section  121  of CERCLA  mandates  that remedies
 must be protective, utilize  a permanent solution  and
 alternative  treatment technologies  or  resource
 recovery options  to the maximum extent practicable,
 and be cost effective.  In addition, cleanup standards
 for remedial  actions  must  meet any  applicable or
 relevant and appropriate requirements (ARARs).

 Standards developed under Section 275  of  the
 Atomic  Energy Act  and Section  206 of the  Uranium
 Mill Tailings  Radiation Control Act (UMTRCA) of 1978
 may be applicable or  relevant and appropriate on  a
 site-specific  basis to  the  cleanup of  radiologically
 contaminated Superfund sites. The EPA promulgated
 40  CFR 192, Health  and Environmental  Protection
 Standards for Uranium Mill  Tailings in January 1983
under authority of these Acts. The pertinent standards
are contained in 40 CFR 192.12,  192.32, and 192.41,
and deal with the acceptable levels of radioactivity in
residual materials and  radiation emission levels from
them, and with disposal requirements. The  disposal
 requirements include  a design life of at least  200
 years, and preferably  1,000 years where  the latter is
 reasonably  achievable.  However,  standards  are
 applicable to uranium mill tailings only. Relevance and
 appropriateness  must  be  determined  according to
 specific site conditions.


 Disposal
 Disposal  can be  in one of two  categories:  on-site
 disposal  or  off-site  disposal. Applicability of  these
 methods  to  Superfund  sites is controlled by site-
 specific factors; therefore, their usefulness must be
 determined  on a site-by-site basis.


 On-Site  Disposal

 Two  methods are  available for  on-site disposal.
 These may be applied  in situ. They are:

        Capping

        Vertical barriers

 Capping is simply covering the contaminated site with
 a  thick layer of  low-permeability  soil. The design
 would be chosen to:  (1)  attenuate  the gamma
 radiation associated with all the radionuclides present,
 (2)  protect  the  ground  water  and 3)  provide
 reasonable assurance  that  release of radon from
 residual radioactive material  to  the atmosphere  will
 not  exceed  acceptable limits.  Capping has  the
 advantages of relatively low cost, ease of  application,
 and  having been used for remediating radiologically
 contaminated sites.

 Capping has  certain drawbacks.  It does not eliminate
 the source of radioactivity; this  limits further use of
 the site. The  cap must be maintained as long as  the
 contaminant exists at  the site.  A  cap  must not be
 penetrated for construction or installation of structures
 and  utility hardware.  Therefore, existing  structures
 must  be  removed before capping.  Also,  horizontal
 migration  of the radionuclides  in ground water  could
 still occur.

 Vertical subsurface barriers (barrier walls) could  serve
 as barriers to horizontal migration  of  radionuclides,
 but perhaps   more  important,  as barriers  to  the
 horizontal  movement  of ground  water  that may  be
 contaminated with  radionuclides.  Vertical barriers  are
 relatively simple to install. They perhaps could  serve
 as the  container  walls  for extraction techniques.
 Disadvantages include  the difficulty  of obtaining truly
 low  permeability   and  the  possibility  of material
 incompatibility  with  waste chemicals.  Before
attempting the installation of  a barrier wall, detailed
data are  required on  the  physical  and  chemical
characteristics of the soil.
                                                    198
-------
 Off-Site Disposal

 Off-site  disposal  can  be  considered for either
 temporary storage  or  permanent disposal.  The
 purpose would be to limit the exposure of people and
 the environment to the radionuclide. This method can
 be applied to both untreated materials and materials
 that  have been modified through a  volume reduction
 process. The waste materials could  be treated before
 disposal to reduce their volume or  to stabilize them
 so that they may  be transported more easily.  Four
 off-site disposal  methods are briefly described in this
 report:
        Land encapsulation
        Land spreading
        Underground mine disposal
        Ocean disposal

 Land encapsulation,  either permanent or temporary,
 has  been the disposal method  most used so far for
 low-level  radioactive  waste  materials.  Land
 encapsulation on site can also occur, but this may not
 be applicable in  all situations. It can be as simple  as
 excavating the  contaminated  material and, without
 further treatment, hauling it to a secure site designed
 for land encapsulation.  The containment  structure
 technology has been used to remediate  radiologically
 contaminated sites.  This  technology  was  originally
 developed for the disposal of hazardous wastes.

 Joint NRC-EPA Design  Guidelines and Combined
 NRC-EPA  Siting  Guidelines  for  Disposal  of
 Commercial Mixed  Low-Level  Radioactive  and
 Hazardous Waste  provide  guidance  on  land
 encapsulation siting  and  design  where  chemical
 contamination is  also a problem  (see Appendix A).

 Selecting a site for a new facility or finding an existing
 site that will accept the waste can be very difficult. In
 addition, the problems of handling  and transporting
 the  waste  must be considered.  If the  radioactive
 portion is first concentrated, as in chemical extraction
 and  physical separation,  additional disposal  issues
 could result due  to higher levels of radioactivity in the
 concentrated  waste.  Advantages  of  land
 encapsulation  include the  relative  maturity  of the
 technology, the complete removal of the waste  from
 the affected site, and the relative  simplicity of the
 prerequisite information needs.

 Land spreading is  a technology  that has  been
considered for  radiologically  contaminated  wastes.
 This technology  involves  excavation  of  the
contaminated material, transporting it to a suitable
 site,  and spreading it on unused  land, assuring that
radioactivity  levels  approach the natural background
level of these  materials  when  the operation  is
completed.

 Land spreading  might be more appropriate for dry,
granular  tailings  and  soils.  It  would  likely be
inappropriate for materials  contaminated with  both
radioactive  and nonradioactive hazardous wastes.
Another  similar method  is  blending with clean  soil
prior to land spreading.

Underground mine disposal could provide secure and
remote containment. Disposal in underground  mines,
either new or existing,   could  be  costly.  The
radiologically contaminated waste could be excavated
and transported without  treatment to the mine  site.
Alternatively,  it could  be  pretreated  for volume
reduction  or  solidified  to  facilitate transport  and
placement.

There would  be  a  tradeoff between  costs  for
treatment or solidification and costs for transportation
and placement. Transportation costs and associated
risks  need  to  be  researched further.  Movement  of
radionuclides into ground water must be considered
and prevented.

Ocean disposal could  be  an alternative to land-
based disposal options.  This alternative  should  only
be  evaluated for low level mill tailing wastes and not
considered  for enhanced radioactive  materials or
concentrated residuals.


On-Site  Treatment
Two methods are  available  for treating  radiologically
contaminated  wastes  so   that  the  radioactive
contaminants may be immobilized. These are:

       Stabilization or solidification
       Vitrification

Stabilization or  solidification immobilizes radionuclides
(and could reduce radon emanation) by trapping them
in an  impervious  matrix. The solidification agent-
for  example,   Portland  cement,  silica  grout,  or
chemical  grout-can be injected  directly into  the
waste  mass or the waste can be  excavated, mixed,
and replaced. It offers the  opportunity to leave the
waste materials on site in an  immobilized state.  It may
be used as additional security for a waste mass  that
will  be capped. The  presence  of other  hazardous
chemicals  could  interfere with  some  solidification
processes.  Although  the  radionuclides are  not
removed  in this process, their mobility and spread in
the  environment are restrained.

Vitrification is  another  process that can  immobilize
radioactive contaminants by  trapping them  in  an
impervious matrix. The  in   situ  process  melts  the
waste  materials between two  or  more  electrodes,
using large amounts of  electricity while doing so.  The
melted material then cools to a glassy mass in which
the  radionuclides are trapped.

Volatilization of  waste substances must be contended
with;  some of the volatiles  may be  vaporized
                                               199
-------
 radionuclides.  Excavation and  vitrification in a plant
 designed  for  the  purpose  can be  done  using an
 electric furnace or a rotary kiln, but dealing with the
 resulting  solids  may  pose  additional  problems.
 Vitrification is  very energy-intensive.


 Radon Control Without Source
 Remediation
 As an  interim measure,  it  may be possible to
 remediate on-site  properties through radon removal
 techniques.  In theory, these may  include the
 following:

        Radon reduction in homes
        Electrostatic precipitators
        Areal soil gas venting and area! removal

 Radon  and its decay progeny do  not  pose  a
 significant  health hazard in an  open  outdoor
 environment.  However,  they  can  accumulate to
 harmful concentrations  in confined spaces,  such as
 residences where there is an underlying radionuclide
 source.

 Direct radon reduction in homes can be accomplished
 in a variety of ways. Techniques include sealing entry
 cracks  and holes, forced ventilation of soil  and
 building materials  in and adjacent to  the foundation,
 and passive and forced ventilation of indoor airspace.
 The techniques, properly applied, are effective. These
 control  systems must be maintained  as long as the
 radionuclide  source  is present.  The  particular
 techniques  to  be applied to  a  specific situation
 depend upon  the  structural characteristics  of the
 building and the nature of the underlying soil.

 Electrostatic precipitators may reduce the number of
 the particles in a  room including  particles to which
 radon progeny are attached. The health effects of this
 are not known.

 Areal soil gas venting may be applicable to reduction
 of radon emanation over a waste site.  The technology
 has been used to  remove methane from landfills and
 organic vapors from  soil. The effectiveness will
 depend in  part on the soil characteristics. Areal
 removal  systems  would  require  long-term
 maintenance.


 Chemical Extraction of Radionuclides
 from Contaminated Soil
 The objective  of  this  separation  technology is to
concentrate the radioactive contaminants by chemical
extraction, with the  aim of thereby  reducing the
 volume of waste for disposal. The chemical extraction
technology  ultimately generates two  fractions. One
fraction  contains the  concentrated radioactive
contaminants and may require disposal; the remaining
material is  analyzed  for residual contamination  and
 evaluated for replacement at the point of origin or at
 suitable alternative  sites.  The various  applicable
 chemical  extraction  techniques include  extraction
 with:

        water
        inorganic salts
        mineral acids
        complexing reagents

 Except  for the use of inorganic chlorides  to remove
 radium from liquid effluents at uranium mines, none of
 the  chemical extraction technologies  has  been  field
 demonstrated  to remove radionuclides from waste
 material at a  site.  Bench-scale  and pilot-scale
 testing  would  be  needed  to  determine  whether
 chemical extraction can be used for site remediation.

 Water can  be  used  to  extract a  portion of the
 radionuclide  contaminants.  Contaminated   soil or
 tailings could be mixed with  large quantities of water.
 The water,  with the soluble radionuclide  fraction,
 could be removed from solids by physical separation.
 Since  many of  the soil-cleaning  techniques  use
 water as part of their process,  this method could be
 used as pretreatment.

 A review of the literature indicates a broad  range of
 results with the use of salt solutions to remove radium
 and  thorium  from  mill tailings and  soils.  In many
 cases the effectiveness of a given salt appears to be
 related  to  several  obvious  variables,  such  as  the
 nature of the  tailings (geochemistry,  particle size
 distribution, and chemical composition); the nature of
 the soil;  the concentration of the salt solution;  pH;
 solid-to-liquid ratio; process time; temperature;  and
 method of extraction.

 Mineral  acid   extraction  techniques are being
 developed and have been used to  extract   radium,
 thorium,   and   uranium   from  mineral ores.
 Improvements  in these acid  extraction processes
 have been found to be possible in the laboratory  and
 at uranium mills.  The results  show  that the  acid
 extraction processes can  remove most of the metals,
 both radioactive  and nonradioactive,  and therefore
 may  deserve  further   study  for  cleanup  of
 radiologically   contaminated  sites  and  tailings.
 However,  different  processes may be  needed for
different radionuclides.

 Extraction  with  complexing agents differs  from acid
 extraction in  that  complexing  agents like EOTA
 (ethylenediaminetetraacetic acid) are used  instead of
 mineral  acids.  Radium forms stable complexes with
many organic ligands (a molecule that can bind to  a
metal ion  to form a complex)  while thorium is  not
likely to be removed  by complexation.  Laboratory
experiments  show  that  radium  forms   stable
complexes  with  EDTA, suggesting the  potential for
                                                200
-------
extraction in soils and tailings with low concentrations
of thorium.

The above  extraction processes  produce a pregnant
liquor  containing the radionuclides.  In  treating  this
liquor to concentrate and collect the radionuclides for
disposal, the following support techniques are utilized:

        precipitation and coprecipitation
        solvent extraction
        ion exchange

By addition of chemicals,  the  radionuclides can be
precipitated out from leach liquor. The slurry from the
precipitation tank is dewatered in thickeners; this  is
followed by filtration. The  filter cake  containing the
radionuclide fraction  is  then  ready for disposal.
Precipitation is a  difficult, cumbersome  operation
requiring complex chemical separation. Close control
of operating conditions is required.

Solvent extraction  can be an  efficient  method for
separating the radionuclides. In  solvent extraction, the
dissolved radionuclide fraction is  transferred from the
feed  solution  into  the  organic  solvent  phase.   The
loaded organic solvent is stripped of the radionuclides
by an aqueous reagent. The barren organic solvent  is
recycled back to the extraction step. The radionuclide
is precipitated  out  from the aqueous liquor. Solvent
extraction offers better selectivity and more versatility
than ion exchange.

Ion exchange involves the  exchange of ions between
the solution and a solid  resin. Ion exchange does not
extract  material from the  soil directly. Rather,  it
separates the  constituents in  a  solution,  such  as
might result from  chemical extraction.  It  has been
used  extensively in uranium and radium  extraction
from ore. There are three types of exchange: fixed
bed,  moving bed,  and resin-in-pulp.  Any of these
are theoretically applicable  to radionuclides in liquids
as a  technique to  complete the  chemical  extraction
technology.

Because of the need for a combination of extraction
methods to remove uranium, thorium, and radium, the
chemical extraction technologies  appear to be quite
expensive and complex.


Physical Separation of Radioactive Soil
Fractions
The  radioactive contaminants in  soils and  tailings in
many cases are  associated with the finer fractions.
This is true for  uranium  mill  tailings  and radium
processing  residue. Thus,  size  separation may be
used  to produce  a reduced volume of concentrated
material  for disposal,  leaving  "cleaner"  fractions.
These fractions must be disposed as well. Physical
separation may be  used with chemical extraction to
produce fractions of smaller volume with even more
 concentrated  contaminant.  The  physical  separation
 technologies may  be  suitable  for  removing
 radionuclides  that originally have been  deposited  as
 solid particulates on the soil.

 Four physical  separation  technologies  may  be
 applicable  to  the separation  of radioactive waste
 components of soils and tailings:

        Screening - both dry and wet
        Classification
        Flotation
        Gravity Concentration

 These processes are already extensively used in the
 extraction of  uranium from ore. They have not been
 used in the field to further  extract other  radionuclides
 from tailings   or  soils.  Pilot  plant testing  would  be
 needed to determine the ability of physical separation
 technology to  clean radiologically  contaminated soils.

 Screening separates soil (or soil-like  material) on the
 basis of size. It is normally applied only to particles
 greater  than 250 microns in size.  The process can  be
 done dry or  by washing water  through the  screen.
 Screening is  not efficient with damp materials, which
 quickly blind the screen.

 Screening can be applied  to  a  variety  of  materials,
 and it is relatively simple and  inexpensive.  It  may  be
 particularly effective as a first operation to remove the
 largest   particles,  followed   by  other  methods.
 Screening  is   a noisy  operation,  and dry  screening
 requires dust control.  Finer   screens  clog easily.
 Information  needs include  size  distribution  and
 moisture content  of the feed stream, and throughput
 required for the equipment.

 Classification   separates  particles according  to their
 settling  rate in a fluid. Several  hydraulic, mechanical,
 and  nonmechanical  configurations  are  available.
 Generally, heavier and  coarser  particles  go  to the
 bottom,  and  lighter,  smaller   particles  (sometimes
 called   slimes)  are  removed  from  the  top.
 Theoretically,   classifiers  could  be  used to separate
the smaller particle  fractions, which  may  contain
much of the radioactive contamination in waste sites.
Classifiers could be used with chemical extraction in a
volume reduction process. Classification is a relatively
low-cost, reliable operation. Soils  high  in  clay  and
sands high in  humus, however,  are difficult to process
this  way. Information required  for selecting
classification   includes   size  distribution,   specific
gravity, and other  physical characteristics of  the soil.

Flotation is a liquid-froth separation  process often
applied  to  separate  specific  minerals  (particularly
sulfides) from  ores. The process depends more on
physical and chemical attraction phenomena between
the ore  and the frothing agents, and on  particle size,
                                                   201
-------
 than on material density. If particles can be collected
 by the froth, flotation is very effective.

 Ordinarily,  flotation is  applied to fine  materials;  the
 process  often  is  preceded  by  grinding  to  reduce
 particle  size.  Process  effectiveness  has  been
 demonstrated in extracting radium from uranium  mill
 tailings (Raicevic,  CIM   Bulletin,  August  1970).
 Detailed  waste characterization  is a prerequisite for
 application  of  the  flotation  process;  mineralogy,
 chemistry,  specific gravity, and  particle size are all
 important.

 Gravity separation is used in  the uranium and radium
 ore  processing  industries. This  process  takes
 advantage  of the  difference  in material densities to
 separate the materials into layers of dense and light
 minerals. Separation  is influenced  by particle  size,
 density, shape, and weight. Shaking (e.g.,  a shaking
 table) and a variety of other motions are employed to
 keep  the  particles  apart and in motion;  this is an
 integral part of the process. Gravity separation can be
 used  in  conjunction with  chemical  extraction.  One
 drawback  to gravity separation  is its  generally low
 throughput.  Information needs  are  essentially  the
 same as for flotation.

 Additional  technologies are required to support
 separation  methods,  including  sedimentation  and
 filtration,  both  of  which are methods used in  waste
 water treatment.  They may  be  used individually or
 together.


 Combined Physical Separation and
 Chemical Extraction Technologies
 The  combined physical  and chemical separation
techniques  that can  be applied to decontaminate
 radioactive soils are:

       Soil washing and physical separation
       Separation and chemical extraction
       Separation, washing and extraction technique

The  soil washing  and  physical  separation process
involves washing the  soil with  chemical  solution,
followed by  separation of coarse and fine particles.
The type of  solution used for  washing will depend on
the contaminant's chemical and physical composition.
In  1972 DOE initiated laboratory-scale studies of soil
cleaning techniques;  on the basis of these studies, a
washing  and   physical  separation  process  was
selected for pilot-plant study of  cleaning  plutonium-
contaminated soil.  The  results  of  that  pilot-plant
testing (at Rocky Flats) show this process to  have
potential for success.

In  pilot-plant test  runs, soils contaminated to  45,
284,  7515,  1305, and  675 pCi/g of  plutonium  were
cleaned to contamination levels of 1, 12, 86, 340, and
89 pCi/g,  respectively, using  different  washing
 processes. The coarse particle weight fraction ranged
 from 58 percent to 78 percent. Soil washing has been
 shown  to work in clay soil.  This process may  not
 work for  humus  soil.  The process is simple  and
 relatively  inexpensive and needs no major process
 development. It would, however, need  further  pilot-
 plant testing  and development work  to  test  its
 applicability to contaminated soil.

 In  combined  physical separation and  chemical
 extraction, the  soil is  first separated into fine  and
 coarse  particle fractions. The coarse particle fractions
 may  be  washed  or extracted.  The  fine  particle
 fractions are combined with extracted contaminants
 and could be  sent to a secure disposal site.  The
 "clean" coarse fractions are  analyzed  for  residual
 contamination  and evaluated  for placement  at  the
 original  site or  an  alternate site. An advantage of this
 process is   that  soil containing higher  levels  of
 radioactivity could be treated. Also,  various sections
 of the  process have  been developed for extracting
 uranium, and laboratory work is underway  in Canada
 for extracting radium from uranium  mill  tailings. The
 main disadvantages  of this  process  are  that  it is
 expensive and  has high chemical usage. In addition,
 the  use of  chemicals raises concerns  of  further
 contamination to the environment. The process would
 need further development work  in  order  to better
 extract radionuclides from  soil.

 In applying the separation, washing, and  extraction
 technique, the contaminated soils can conceivably be
 washed with  a  variety of  washing fluids, followed  by
 chemical extraction. The nature of the washing fluids
 and  chemicals  depends on the contaminants and  on
 the  characteristics of  the soil.  It could  be
 advantageous  to  separate the  soil into  fine  and
 coarse fractions and use the washing system  on the
 coarser  soil  fraction  to reduce  the  throughput and
 chemical  usage.  The treated   soil, the  finer  soil
 fractions  and  the collected  contaminants  would
 require appropriate disposal.


 General Issues
 Several  issues are of  significant concern in attempting
to apply remedial technologies  at sites contaminated
with radioactive materials. They include:

        Final  Disposal and Disposal Siting. Publicly
    acceptable  sites  are difficult  to  find, and  there
    may be problems  in convincing the public that the
    "clean" fractions  of the treated wastes are truly
    acceptable. Some form of disposal may ultimately
    be necessary as radioactivity cannot be  altered or
   destroyed by any treatment technology.

        Handling of concentrated residuals.  Reduc-
   ing  the  volume of radiologically  contaminated
   waste  will increase  the  concentration   of
                                                  202
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    radionuctides  and may  substantially increase the
    safety hazards of the contaminated fractions.

    •   Mixed Wastes. It is important to note that in
    some cases  there  may  be two  categories  of
    residual contamination:  process wastes and soils
    contaminated  with isolated radionuclides  or
    groups of radionuclides.  While  removal  of  the
    radioactive  fractions of soils contaminated with
    single radionuclides such as uranium or plutonium
    might result in "clean" fractions acceptable for
    unrestricted disposal, removal of the radioactivity
    from a  soil  contaminated with  process  wastes
    may not. In this second case, the nonradioactive
    fractions of  the  residues could  result in an
    unacceptable  product.  Therefore,  before
    considering  any  separation technique, it  is
    necessary that acceptable limits for both  the
    radiological   contaminants  and  the  non-
    radiological  contaminants  be  defined. In  some
    cases  multiple  treatments   or  combined
    technologies  could be  required to  achieve
    environmental goals.
land.  Alternative  technologies,  which  have  to  be
evaluated  and discussed further,  may  have  the
potential  for reducing the mobility, toxicity, or volume
of these contaminants.  Further  studies need to  be
completed prior  to the  implementation of  these
alternatives.
Criteria for Further Studies
The utility of any potential treatment process  and the
applicability  of  the  overall remedial  action  depend
heavily  on the  physical characteristics  of  the
contaminated media and the surrounding soils.  Since
none  of  the  chemical  extraction and physical
separation  technologies have  been used in a  site
remediation situation, their  application  must be
approached  cautiously. The  same holds  true for
solidification or stabilization processes.  Only  land
encapsulation and ocean disposal have been used.

It  is  important to  study  the patterns  in  waste
characteristics  at various sites and  develop waste
groups with  similar major characteristics. Applicability
studies can identify  promising technologies to be
tested for treatment of each waste group.  Preliminary
screening of the technologies  can  be accomplished
based primarily  on the waste characteristics.

When one or more remediation  concepts are selected
that appear  applicable to  a site, plans may be  made
for  treatability studies.  Success there could  lead to
pilot-scale  testing   and  eventually to  full-scale
demonstration  of  site  cleanup.  This  step-wise
procedure is essential for  the development  of any
remediation technology, with carefully developed work
plans and quality assurance plans  preceding  each
step.


Conclusions
The  remediation of  radioactively contaminated sites
under Superfund,  FUSRAP, and UMTRAP has been
hampered  by  the  lack   of methods  other  than
temporary storage or permanent  encapsulation on
                                                 203
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204
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            Enargy. Mnn and
            B«oi»e«« Canada
            CANMET
            Canada Centre
            lor Mineral
            and Energy
            Technology
Erwrg*. was tt
Resource* Canto
Centre Canadian
da la tecnnolog*
daa mmtrauK
al da renergie
RAOIUM(226) REMOVAL FROM A CONTAMINATED SOIL

                     by

                 K.E. Haque*
no
o
\_n
           RADIUM(226) REMOVAL FROM A CONTAMINATED SOIL
           K.E. Haque
           Extractive Metallurgy Laboratory
           November 1988
           For presentation at  'Workshop on Extractive Treatment of Excavated Soil";
           Dec.  1-2,  1988. EPA-Edlson, N.J.. U.S.A. and for publication In the Workshop
           Proceedings
           Project:   30.86.01
                      Tailings  Characterization and  Treatment
                                                                                                                       ABSTRACT

                                                                                              Approximately 4000 tonnes of radium(226) contaminated soil have
                                                                                     been Identified In 10 acres of land near a residential area In Ontario.
                                                                                     Rad1um(226) level 1n the as received soil was 105 pCI/g soil.  Radium
                                                                                     removal by chemical treatment was undertaken.  The soil was leached with
                                                                                     add (HCl. HNO,). chloride salts and EDTA respectively.  Leach results
                                                                                     Indicated that radium In this soil was refractory.  The best radium
                                                                                     extraction (621) was obtained by leaching with 600.0 g HCl/kg soil or with
                                                                                     151.0 g KCl/kg soil with 501 solid In the leach slurry.  Because of the
                                                                                     refractory nature of the radium It would be a logical alternative  to remove
                                                                                     the 4000 tonnes of the contaminated soil from the present location and
                                                                                     dispose of It In a uranium mill tailings site or In an underground
                                                                                     depository, such as a uranium mine.
            MINERAL SCIENCES LABORATORIES
            DIVISION REPORT MSL 88-143 (OP&J)    DRAFT
            Crown Copyrights Reserved
                                                                                     Keywords:  radium, contaminated soil, leaching, refractory  radium

                                                                                     * Research Scientist, CANMET, Energy Mines and Resources  Canada,  555 Booth
                                                                                       Street. Ottawa. K1A OG1
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rv>
o
                               INTRODUCTION

         Rad1um(226)  1s  the most abundant naturally occurring radioactive
element.  It Is the nuclear disintegration product of uranium and thorium
and generally occurs  within their minerals In minute quantities (3.3x10"'
part R«(226) per part of uranium)  (1).  Once radium was a highly priced
element, but now It  has  little commercial value.  Its principal applications
were 1n the field of cancer treatment  and In the manufacturing of luminous
dials for watches (2).  Today synthetic radlolsotopes are being utilized 1n
place of radium.  Because of  scarcity  and high  toxUUy, further commercial
or clinical applications of radium have never been  explored.
         In the early days of the processing of radioactive elements  (e.g.,
Ra(226). u, Th) health hazards associated with  radiation were not  fully
understood.   Generally,  the industries processing the radioactive  elements
used to dispose of the  radioactive waste without sufficient consideration  of
potential  environmental  nazaras.  Recently, some disposal  sites of this
nature  have been  developed for residential  and commercial  purposes.  As a
 result  these places  have become the centers of serious environmental
 concerns.
          For example, an almost  10 acre piece  of land near a residential
 area In Ontario has  been recognized as being contaminated with rad1um(226).
 Haclaren Engineering. Inc. of Toronto, conducted a radiation survey at this
 site and their results  Indicate  that  approximately 4000 tonnes of
 radlum(226) contaminated soil having  • radium  level  on the  average of  37
 pCI/g son are present 1n that area.
          The  Extractive Metallurgy Laboratory  of CANMET undertook  the
 responsibility to develop chemical  Methods for the removal  of  radium from
 this contaminated soil.  The radium level  of  the as  received soil  was 105
 pCI/g  soli.   The radioactive materials can be  removed from the contaminated
 soil by various methods, for example  by leaching with add, a chloride salt
 or  a chelatlng reagent, or by gravity separation.  CANMET's objective was to
 remove almost all of the  radium and  to obtain soil with background level  of
 radium of 2-3 pC1/g soil.
                              GENERAL PROCEDURE

         The rad1um(226) contaminated soil  sample (approximately 10 kg) was
supplied by MacLaren Engineering Inc.  Wood chips and stone pieces were
removed by sieving.  The air dried soil was sized to 80% -200 mesh (74 urn).
All the leach tests were conducted on 250.0 g soil per test.  The calculated
amount or the reagent and water was added to the soil sample In order to
maintain a definite initial concentration of the reagent and solids in the
leach slurry.  At the end of leaching the leach slurry was filtered and the
residue was washed with water.  Dried residues and the filtrates were
analyzed for rad1um(226).  Unless otherwise stated radium In this report
refers to rad1um(226).

                           RESULTS AND DISCUSSION

         The sizing results of the soil Indicated that the higher concentra-
tion of radioactivity appeared In the finer fractions (e.g.. 155-165 pCI
Ra/g soil of -325 mesh);.however, the concentration of radioactivity in the
finer fractions was not high enough  to follow this route of  radium removal
from thli soil.  Consequently, attention was focused on the  chemical methods
of radium removal from the soil.
         A series of leach tests was conducted on the soil utilizing either
water, hydrochloric acid or nitric acid.  This leach program was based  on
the assumption that If the radium compound or compounds In the  soil were
soluble or even slightly soluble In  acid then almost radium  free soil  could
be obtained.  Table 1 shows the leach  results.

       Ttble  1.  Acid leaching of the  soil  (501  solids. 2  h  retention)
leachant
(9/kg soil I)
H,0
•
HCl - (44.0)
HCl - (600.0)
HNOj, . (210.0)
Temp
•c
22
SO
22
•
50
Ra-grade (pCI/g)
Feed
IDS
1
Residue
103
100
98
30
135
Radium
Extraction
wt X
1
5
7
78
Weight
loss
wt t
6
21
22
-------
         These leach results  clearly confirmed that radium In this sol!  was
present 1n the form of a sparingly  soluble  salt or salts, such as RaSO.,
Ra8a(SO,), or RaPb(SO.),.  Water  leaching at SO'C could not solublllze more
than 51 of the radium.  Ho-e.er.  the best leach residue In terms of the
lowest radium concentration (30 pd/g)  soil was obtained by leaching with
600.0 kg HCI/tonne soil; however  the acid consumption was quite high (260.0
kg HCI/tonne soil).  Nitric add  leaching essentially could not solublllze
any radium from the soil.
         The extraction data In Table  1  lead to the conclusion that the
solublllzatlon of radium took place at  high acidity through equilibration
between the sparingly soluble radium compound  (e.g., RaSO.) and the chloride
anlon (Cl~) (equ. 1).
         RaSO. + 2C1-
>RaCl, + SO!"
(1)
         These results Indicated that radium extraction may even take place
by leaching with C1~ under mildly acidic  conditions or with excess Cl~ In
the  leach slurry.  Accordingly, a series  of tests was conducted on the
contaminated  soil with water acidified to pH t.O - 2.0 with hydrochloric
add. and also with chloride salt solutions (e.g., NaCl, KC1) respectively.
Table 2 and 3 show the leach data.
       Table  2.  Chloride leaching with low acidity (30'C, 2 h, pH  1.6)
Leachant
H,0 ••• HC1
•
Pulp density
« solids
20
•
Ra-grade (pCl/g)
Feed
105
•
Residue
60
40
Ra-extractlon
wt S
43
62*
 * The soil  sample  was prewashed with carbontetrachlorlde,  ethanol  and  final-
   ly with water.
         The leaching of the soil  with water alone provided marginal
extraction of radium (Table 1), but leaching with water acidified with
hydrochloric add to pH 1.6 provided 431 of radium extraction and yielded a
residue with 60 pCt Ra/g soils.  However second stage leaching on the first
stage leach residue with the fresh water and hydrochloric mixture at pH 1.6
improved radium extraction marginally (2-31).
         Generally, some organic matter such as humlc add or hydrocarbon
residues 1s present in the soil.  This organic matter may cause Inefficient
extraction of radium.  Therefore addle water leaching was conducted on soil
samples prewashed with CC1., ethanol and then finally with water.  Radium
extraction Improved to 62X and the leach residue contained 40 pCI Ra/g
soils.
         Radium leaching from  the uranium mill tailings with a salt chloride
solution such as NaCl or nC: :r oy a chelatlng reagent (e.g., EOTA) 1s well
documented 1n the  literature (3,4).  Accordingly, a  series of tests was
conducted on the soil with NaCl, KC1 and EDTA respectively.  Leach results
are shown in Table 3.
                                                                                     Table 3.  Leaching with chloride salts and EDTA
Leachant
g/kg
NaCl - 117.0
•
KC1 - 151. 0
•
EOTA -
100.0
•
•
Pulp
density
X solids
SO
•
m
10
so
•
20
Temp.
•c
22
SO
22
•
22
SO
22
Time
h
2
•
•
•
•
•
•
Ra-grade. (pCl/g)
Feed
105
•
•
•
•
•
. •
Residue
80
76
40
65
85
75
80
Ra-extractlon
wt t
25
28
62
38
20
29
24
                                                                               The extraction data in Table 3 demonstrate that radium is
                                                                      extractable by leaching with both chlorides anlon (Cl~) or by a complexing
                                                                      reagent such as EOTA.  In this test program both NaCl and KC1 were applied
-------
             separately for the leaching of radium from the soil.   However,  potassium
             chloride Is more effective than sodium chloride.   The highest radium
             extraction (621) was obtained by leaching with 151.0  g KCl/kg soil  with SOS
             solids In the leach slurry, but the leach residue stilt contained 40 pCt -
             Radium per gram of the soil.
                      A complexlng reagent such as EDTA (ethtenediamlne tetracetate) was
             also effective In the extraction of radium from the soil but was not so
             effective as NaCl or KC1.  Here the highest percent of radium extraction
             (29%) was obtained by leaching with 100.0 g EDTA/kg soil, at SO'C with SOS
             solids In the leach slurry.
                                                                                                     4.  K.E. Hague and G.M. Rltcey; 'Leaching of radlonuclldes  from uranium mill
                                                                                                         tailings and their flotation concentrates by hydrochloric acid and
                                                                                                         chloride salts'; Hydromet. 11. 91-103;  19S3.
                                     CONCLUSION AND RECOMMENDATION
(V)
o
en
         The radium compound(s)  present  In the soil sample was  refractory to
chemical  leaching,   water leaching of  the soil removed  essentially  no
radium.  Neither strong add nor concentrated chloride  salt  solutions were
effective in complete removal of radium  from the soil sample.   The  most
aggressive leaching (600.0 g HCl/kg soil) yielded a residue  with  30 pCI
radium per gram of soil.
                        **4i,^,
         The removal of setftam- f rom this soil by chemical methods will
require further work.  As well,  the recovery or removal of Ra(226)  from
leach liquor is still an unresolved problem.  In view of these  limitations
and the apparent chemical stability of Ra compounds,  the physical removal of
these 4000 tonnes of radium contaminated soil from  the  present  location  and
disposal 1n a uranium mill tailing sites or  In an underground depository of
a uranium mine, would be a logical choice.
                                               REFERENCES

              1.  Textbook of Physical  Chemistry;  by  S. Glasstone,  2nd  Edition;  Pub. by
                  D. Van Nostrand Company,  Inc. 1946.

              2.  K.E. Haque; 'The leachablllty of radium  from uranium  ores';  C1H Bulletin
                  80(908). 76-82; Dec.  1987.
              3.  I. Nlrdosh; *A review of recent developments  in  the  removal  of "*Ra  and
                  "•Th from uranium ores and mill tailings'; Uranium  4,  83-95;  1987.
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                       INTERIM REPORT
INVESTIGATION OF FEEDSTOCK PREPARATION AND HANDLING
      FOR MOBILE ON-SITE TREATMENT TECHNOLOGIES
                               by

                       William F. Beers, P.S.S.
                         Roy F. Weston, Inc.
                       EPA OHMSETT Facility
                      Leonardo,  New Jersey  07737

                            Contract No:
                            68-03-3450

                          Project Officer.
                       Richard P. Traver, P.E.
                 Program Manager/Soils Treatment Team
                       Releases Control Branch
                  Risk Reduction  Engineering  Laboratory
                       Edison, New Jersey 08837
              OFFICE OF RESEARCH AND DEVELOPMENT
              U.S. ENVIRONMENTAL PROTECTION AGENCY
                      CINCINNATI, OHIO 45268

                          DECEMBER 1987

                             209
-------
210
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                                NOTICE

        The information in this document has been  funded wholly or
    in pact  by the  United States  Environmental  Protection Agency
    under  Contract  No.  68-03-3450  to Roy F.  Western,  incorporated
    (WESTON).   It has  been subject  to the Agency's peer review and
    administrative review,  and it has been approved for  publication
    as  an EPA document.   Mention  of  trade  names  or commercial
    products  does not  constitute  endorsement  or recommendation for
    use.
ro
                                  -ii-
                           ABSTRACT

    The principal  objectives of  this  study were as  follows:

    •    To categorize materials found  at Superfund sites.

    •    To  review  current  technologies  for  separation  of
         contaminants    from     feedstock    excavated    soils,
         sediments, and sludges.
                                                                                               To  conduct   experimental
                                                                                               preparation equipment.
                                     evaluations  of   feedstock
    •    To provide  recommendations  for future  research needed
         on feedstock preparation technologies.

    Categories of  the debris matrix  associated with  hazardous
wastes were determined by interviews  with  personnel associated
with Superfund sites.  The quantity  of debris  varies  consider-
ably at sites, ranging from  less than 1 percent to greater than
80 percent.  For the purposes of this  report, debris is defined
as any material which cannot  be handled by a treatment process.

    The  contaminated  materials  found  at  Superfund  sites have
wide variability.  They range in size  from  submicron-sized col-
loidal particles to  entire  tanks and buildings.  The physical
and chemical  relationships between contaminants  and debris are
exceptionally  diverse.  Contaminants  can  appear as  ions dis-
persed in  groundwater, as solids,  or  as liquids  dispersed on-
site.  The  initial  patterns  of  concentration have been modified
through  both  natural and man-made  processes.  Therefore,  the
contaminants may be an inherent part  of the material, may occur
as a  discrete phase within the matrix, or  may  be found only  on
the surface of the debris.
                                                                                                                   -iii-
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(V)
    The  most  frequently  occurring  National  Priorities  List
(NPL) materials were those  encountered  at  municipal solid waste
landfills.    These  materials  exhibited  the  full  spectrum  of
sizes, compositions, and material-handling problems.


    The  study  found  that the  selection  and  performance  of
technologies  for  feedstock  preparation,  debris  handling,  and
effluent  treatment  are  all  predominantly   influenced  by  the
following factors:


    •    Feedstock size requirements.


    •    Type of contamination.


              of dominant matrix.
       •    Type  of  debris  (size,  shape,  phase,   form.  Btu  and
           recycling values).


       •    Quantity  of  debris  (percentage by volume or weight).


       •    "Clean-up"  standards or target levels (Federal, state,
           local,  private).


       •    Potential for  decontamination  of the debris.


       Although conventional equipment exists  to  handle all feed-
   stock  preparation required by current  mobile on-site equipment,
   there  is much  room for  improvement  of this  approach.


       This   report  was   submitted   in   partial   fulfillment   of
   Contract  No.  68-03-3450  by  Roy F.  Weston,  Inc.  (WESTON) under
   the sponsorship  of   the  U.S.  Environmental  Protection  Agency.
   This report  covers   a  period from  September  1987 to  September
   1988.  and  work completed as  of August IS,  1988.
                                -iv-
                           CONTENTS

Notice	ii

Abstract	iii

Figures	vii

Tables	vii

    V.   Introduction	%	1
              Background	1
              Objectives	3
              Approach	4
    2 .   Conclusions	6
    3 .   Recommendations	8
    4 .   Superfund Site Material Characteristics	10
              Types of Materials	10
              Superfund Site Debris	16
              Hazardous Material Handling Characteristics	24
    5.   Feedstock Preparation and Debris Handling
         Equipment	27
              Equipment Requirements	27
              Types  and Categories of Equipment  Available	30
                   Excavation equipment	32
                   Size modification equipment	35
                   Separation equipment	37
    6.   Feed Preparation for Selected Mobile On-Site
         Technologies	46
              Descriptions of Selected Processes	46
              Biological Treatment
                   Activated sludge process	46
              Chemical Treatment
                   Dechlorination	52
                   Neutralization	SS
              Physical Treatment
                   Soil washing	.".59
              Thermal Treatment
                   Rotary kiln  incineration	64
     7 .   Feedstock Preparation  Practices	71
               Infrared  Incinerator	72
               Rotary Kiln  Incinerator  at Beardstown, Illinois.75
               Low-Temperature Thermal  Stripping	80
               Soil Washing	84
               Rotary-Disk  Filtration	88
     8.   Feedstock Preparation  Equipment Data Base	91

 Bibliography	96
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     Appendices

         A.   Debris List..

         B.   Vendor Lists.
.A-l

.B-l
                                                                                                                      FIGURES
1    Classification of  Superfund sites	12
2    Frequency of occurence/size relationship for
       processing equipment	14
3    Size/moisture continuum of NPL site materials	IS
4    Elemental units in feedstock processing	31
5    Activated sludge process flow diagram	47
6    Mobile soil washing technology process flow diagram..60
7    Rotary kiln process flow diagram	65
8    Peak Oil site process flow diagram	76
9    Lauder Salvage Yard rotary kiln incinerator
       process flow diagram	78
10   LT3 Feedstock preparation process flow
       diagram	83
11   Schematic of the EPA Mobile Soil Washing System	86
12   ATAM equipment test results	90
r>o
M
uo
                                                                                          Table

                                                                                              1
                                                                                                                      TABLES
                                  Debris  size requirements for  mobile on-site
                                    treatment	
                                                                                     Page
                                                                                                                                                        18
                                                                                                   Debris handling at Superfund sites	20
                                   -VI-
                                                                                                                       -vii-
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                              SECTION  1
                            INTRODUCTION
   BACKGROUND
       In the  past  decade,  there  have been  numerous legislative
   requirements and  incentives  for  more complete  remediation at
   hazardous waste  sites.   Under  the  Comprehensive Environmental
   Response, Compensation,  and Liability Act of 1980 (CERCLA), the
   current National  Contingency Plan  (NCP)  that implements it, and
   the Superfund Amendments and Reauthorization Act of 1986 (SARA)
   requirements, actions  must  be taken  at  hazardous  waste sites to
r\j reduce the  threat of  uncontrolled waste releases  to  the envi-
j±r ronment.   In the 1984  Resource Conservation and  Recovery Act
   (RCRA) Amendments,  the  U.S.  Congress clearly showed its intent
   to minimize the volume of  solid waste  disposed-of   in  land-
   fills.  RCRA-based policy  would mandate  a major change  in the
   current  practice, at  CERCLA  sites,  of removing the  hazardous
   waste  material   and   burying it  elsewhere  without  any  prior
   treatment.
       The policy of  the  EPA'8  Office of Solid Haste and Emergency
   Response  (OSWER),  which  is  responsible  for  implementing the
   1984 Hazardous Solid Haste Amendment (HSHA) requirements,  is to
   discourage the  excavation  and  reburial  "disposal"  philosophy
   for CERCLA waste and  debris.  Instead, OSWER  encourages  the use
   of  on-site  technologies  to  eliminate  or  reduce  the hazardous
   character  of  the waste  materials,  since  on-site  treatment
   achieves  more  positive  control  than  containment.    In the
   future, off-site disposal  to engineered and protected landfills
   will only be allowed  when no destruction  technology is avail-
   able, or  for "pretreated"  soil  and  debris materials complying
   with Best  Demonstrated Available Treatment (BOAT)  levels, as
   promulgated under  the  impending  1988  Land Ban legislation.
                                 -1-
    This body  of  legislation  has created  a pressing  need for
more economical and effective  technologies  to  detoxify material
at  existing  hazardous  waste  sites.    As  landfill  disposal
becomes more expensive and as  hazardous  waste  transportation is
more stringently  regulated,  on-site waste  destruction or volu-
metric  reduction  technologies  will  become  far  more desirable,
providing  that  technologically  feasible,  environmentally safe,
and economically viable treatment systems can be developed.

    In  order  to destroy  or  reduce  the hazardous  character of
any  contaminated  material,  any  treatment  technology selected
must  receive  a "feedstock"  having  a  predetermined  range of
physical/chemical  characteristics in  order to  assure reliable
treatment  efficiencies  and  cost-effectiveness.   The  types of
contaminated  materials  identified  and  discussed  in Remedial
Investigation/  Feasibility Study (RI/FS)  reports  are  primarily
soils,  sludges,  and   liquids.   The  debris component  was  pre-
viously an  issue  in  remediation  if  the  contaminated   matrix
consisted  primarily of  a mixture of  materials (i.e., building
demolition debris or  sanitary landfill wastes, such as  house-
hold  trash and garbage). On  a  Superfund  site, such  materials
may  be  small   in  volume but  may be  the cause of   all  of  the
process upsets to a treatment system.  Current practice involves
the  time-consuming task  of  individual  decisions  regarding  the
separation of  potentially damaging  materials.  The land disposal
rules,  scheduled  to  be enacted  in  November 1988,  will  address
the  disposition of  feedstock  and site  debris, as  well  as con-
taminated  soil, under the Land Ban  legislation.

     The review conducted  in this study, of numerous  Records of
Decision  (RODs)  and  RI/FSs,   indicated  that there  is  a  lack of
site-specific  historical data quantifying  and qualifying Super-
fund debris.   Few,  if any,  RODs or RI/FSs  take into considera-
tion  factors  such as on-site excavation, handling, segregation.
                                                                                                                      -2-
-------
rv>
sizing,  and  delivery of  feedstock to  the various  recommended
mobile  on-site technologies,  such as  biological  degradation;
chemical  treatment,  e.g.,   potassium-polyethylene  glycol   (K-
Peg),  solidification/stabilization,  incineration,  low-tempera-
ture  thermal  desorption;  and  physical  treatment,  e.g.,  soils
washing.    The   lack   of   published,   information   regarding
requirements for  feedstock  treatment  and  feedstock  preparation
practices  is   a  significant problem.    It  is  critical  that  an
engineering and economic  evaluation  of  the  types of materials
and  their  impact  on the  above  technologies  be  performed  in
order to assure successful  implementation  of on-site treatment
processes  in  the  future.    This Risk Reduction  Engineering
Laboratory (RREL)  study  addresses these  issues.

OBJECTIVES

    The objectives of this study were  as follows:

    •    To categorize Superfund-related solids,   sludges,  sedi-
         ments, and materials  according   to  excavation,  hand-
         ling,  and  separation  problems,  including a discussion
         of the frequency  of problem occurrences.

    •    To provide  a  written  summary  on  the state-of-the-art
         technologies  for  isolation/separation   of  materials
         from feedstock  soils,  sediments, and sludges.

    •    To  provide  recommendations  for  future ' research   on
         feedstock  preparation  technologies  that have a high
         probability  of  success  and  that  are   applicable   to
         frequently occurring material-handling problems.

    •    To provide an engineering analysis of feedstock  prepa-
         ration and handling  methodologies  for   the following
         candidate on-site treatment technologies:
                                 -3- .
              Incineration
              Low-Temperature Desorption
              Chemical  Treatment (K-Peg)
              Solidification/Stabilization
              Physical  Treatment (Soils Washing)
              Biological Degradation

    Each of  the  six  mobile  on-site  technologies  reviewed  re-
quires that  the feedstock material  be delivered  within prede-
termined specifications so that the selected treatment  hardware
can reliably, efficiently,  and cost-effectively  destroy or  re-
duce  the  contaminants  of  interest.   To accomplish  this  task,
the contaminated  material,  which may  be soil,  sludge,   liquid,
or debris,  must be prepared by either of the following methods:

    •    Physical  pre-processing  or   oversized  material   con-
         ditioning   (e.g.,    crushing,   shredding,   screening,
         separation, dewatering, etc.).

    •    Chemical  preconditioning,   such as  neutralization  and
         reduction/oxidation.

APPROACH

    The  approach  to  analyzing  the  suitability  of  available
feedstock  preparation  equipment   for   Superfund  site   cleanup
through mobile  on-site treatment technologies  consisted of  the
following:

    •    Definition   of   contamination   and  material   matrix
         characteristics  at  Superfund  sites.

    •    Literature  reviews  to  review and  identify  past  and
         current  trends in feedstock preparation.
                                                                                                                       -4-
-------
ON
    Unit  operations  in  the  feedstock  preparation
    process.

    Historical  and currently available equipment,  as
    well  as equipment currently  under  development  for
    these or similar unit operations.

    Previously  developed  specialized  equipment  for
    use   with   the  six  mobile  on-site  technologies
    reviewed in this report.

Investigation of constraints on  feed  materials to the
current on-site  treatment technologies:

     Interviews  with experts on  each  mobile treatment
     technology.

On-site evaluation of the  feedstock preparation proc-
ess for  operating mobile  on-site  treatment technolo-
gies:

     Review of  unit operations.

     Review of problems  and upsets  in  unit operations.
                      \
     Review of  skill levels and operating experience.

     Review of  successes  and  failures  in  the  use  of
     such equipment.

 On-site  field  testing  and evaluation  of  new feedstock
 preparation unit  operations.
                                  -5-
                           SECTION  2

                          CONCLUSIONS

1.   Tightening regulatory restrictions on  landfills  promises to
    sharply drive up  the cost of  waste disposal  in the United
    States.   At Superfund sites, this  trend provides  a growing
    impetus to  reduce  off-site shipments  of materials during
    remedial actions by more  thoroughly  processing contaminated
    materials  on-site.   The  resultant  need for  processing on-
    site of greater quantities  and varieties of  materials cre-
    ates a  strong  motivation for  development of  more effective
    systems to  prepare feedstocks for  mobile  treatment  proc-
    esses.

2.   An adequate technical base  for the development of feedstock
    preparation systems exists  in  the equipment  currently used
    for  excavation,  materials  transport,   size   reduction,  and
    material separation  in  the construction, chemical process,
    refuse-derived fuel,  and municipal  solid waste industries.
    However, the unique environmental, health,  and safety prob-
    lems raised  by processing  diverse  hazardous materials on-
    site hinder  the direct  use of  off-the-shelf  equipment in
    remedial actions.  It  is  likely that most improved feedstock
    preparation  equipment will  be  based   on  modifications of
    conventional machinery,   rather  than  on radical  new tech-
    nologies .

3.   There  is  extreme  variety among  Superfund  sites  regarding
    relative  amounts   and types of  contaminants,  material ma-
    trixes, ease  of matrix  decontamination, and best  contami-
    nant treatment.  To  accommodate  this site-specific  diversi-
    ty, it is generally preferable to  install  a  standard  mobile
    contaminant treatment system on-site and to  employ  a  flexi-
    ble  set of  feedstock preparation  operations to  produce  a
    stable, uniform feedstream.
                                                                                                                     -6-
-------
         In order  to  establish  priorities  for  the development  of
         feedstock   preparation  equipment,   a  systems  engineering
         approach   is  needed  to  analyze  various  combinations  of
         feedstock  preparation,  contaminant  treatment,  and  residue
         disposal   operations.    This  approach   implies   iterative
         redesigns  examining  interfaces  between  feedstock  prepara-
         tion,  contaminant  treatment,  and residue disposal  in  order
         to identify those  changes  that  would most  improve  overall
         on-site remediation.
(V)
                                  -7-
                       SECTION 3

                    RECOMMENDATIONS

Since  the  development  of  feedstock  preparation  equipment
will  likely  involve  site-specific adaptations  of  conven-
tional equipment,  it is recommended that  further  investiga-
tions continue  to  emphasize on-site demonstrations  of unit
operations traditionally  used in  the  municipal  waste,  re-
fuse-derived  fuel,   chemical   processing,  and  construction
industries.  The  numerous  candidate  feedstock  preparation
technologies discussed  in  this  report  should be  tested in
early demonstrations in order  to qualify them for use with
improved  technologies   now being developed  for  hazardous
waste treatment.

A  systematic analysis  of  the  technical  requirements  for
on-site  mobile  feedstock  preparation  and  residue disposal
systems  should  be  performed  to  identify  the  greatest
technology  development  needs  on  a  national  scale.  Con-
sideration  should  be  given to  the types  of materials at
Superfund  sites  and  the  feedstock  constraints  of   mobile
on-site    treatment   systems.     Technology   development
candidates   should   be   ranked   by   potential   national
contribution  to Superfund site remediations  in terms of
human  health  risk  reduction,  decreased  costs,  number of
sites, and/or quantity of  contaminants treated.

In order to  facilitate  the testing of feedstock preparation
equipment  under controlled conditions,  work  should  continue
on creating  standardized  debris.  A "universal debris"   may
provide  the best  initial  screening test  for new feedstock
preparation  technologies.  Follow-up  tests  using  selected
debris types may  prove useful  in determining processing ca-
pacity versus debris content,  wear points, types  of  process
upsets,  and materials  that can be handled.
                                                                                                                      -8-
-------
oo
4.   An attempt  should be  made  to  gather  better  information
    about  Superfund debris.   The survey of RODs  and  telephone
    interviews  made for  this report  indicated  that there  was  a
    lack  of  useful information about debris characteristics. It
    is recommended that  a  standard  table  describing  debris
    types  and supplementing current  RI/FS documentation be cre-
    ated,  in order to  capture  information from ongoing efforts.

5-   It is recommended that follow-up  studies  be performed as
    follows:

    a.   Work should  be  continued on  maintaining a data base
         for mobile   and   transportable  separation  equipment,
        which   contains   current   information   on   commercial
         sources.    costs   (lease/purchase.   operation    and
        maintenance),   debris  applications,   and  anticipated
        performance.  This  data  base  will be  of  use to  EPA
        remedial   project   managers.    on-site   coordinators,
        contractors,  and engineering/response personnel.

    b.   Additional pilot-scale feedstock preparation  equipment
        tests  should  be conducted.

    c.   Detailed   engineering  reviews  and evaluation of  the
        most widely  applicable  Vendor  technologies for  feed-
         stock  preparation  should be performed,  with particular
         emphasis   on  the  equipment used   in  municipal  solid
        waste  recycling programs.
                                -9-
                                                                                                                  SECTION 4
                                                                                                   SUPERFUND SITE MATERIAL CHARACTERISTICS
TYPES OF MATERIALS

    Superfund sites contain  hazardous materials and the variety
of items usually  found  in municipal  solid waste  sites.   Analy-
sis of  the National Priority List  (NPL)  indicates that 18 per-
cent  of Superfund  sites  are.   in  fact,  municipal  landfills.
Historically,  many  of  these  municipal  landfills  have  been
receptors  of  drummed   industrial   wastes,   sludge,  and  free
liquids. The  remaining  sites usually have some material that  is
similar  in  structure  or composition to that characteristically
found  in municipal  landfills.   The primary difference between
municipal  solid wastes  (MSWs) and  the  materials  found at  other
sites  is the amount of inorganic materials.  The  high  amount  of
inorganics  in MSWs  stems  from the disposal practices used,  such
as  daily covering  of  the waste  soil materials,  as well as  the
migration of pollutants  into the  soil and bedrock  at the site.

    Characterization  of Superfund  materials has  been  attempted
by  several  authors.  The volume  of hazardous  wastes by  major
categories  was  estimated   in  a  1974  EPA  report.  Categories
included aqueous solutions  of  organic  and  inorganic compounds,
comprising 88.6  percent of  total  wastes;  pure  organics,  com-
prising 8  percent;   and solids   and  sludges,  comprising  the
remaining  3.4  percent.  These  figures  represent  wastes  gener-
ated,  not  waste materials found at NPL sites.

     In order to  identify likely  feedstock  handling problems as
 applied to feedstock preparation systems,  a statistical  sample
 of  the  888  NPL sites was studied.  This  sample was surveyed  for
 the types   and sizes of  solids contamination,  the presence  of
                              -10-
-------
sludges,  the  presence of  free  liquids,  and the  presence  of
sediments.  The results of this survey are summarized  in  Figure
1. which shows  the  frequency  of  occurrence of these  classes  of
materials.  This  sample is  representative of  HPL waste  sites.
However,   these  NPL  sites  are  significantly biased in  their
emphasis on the  liquid phase, which  is  a significant criterion
for  inclusion on the KPL  list.   The results  shown  in Figure 1
should not  be considered representative of the  total national
population  of waste  sites.   Analysis of these  sites indicates
that groundwater and/or surface  water contamination was present
at almost all sites.

     The  most important  site variable  affecting  handling  of
materials  of the type found  on  Superfund sites  appears  to be
moisture  content,  which drastically affects the  gross physical
 properties  of the waste.  The moisture content of raw municipal
 waste varies  considerably from  the  sludge  effluent  of  the
 Publicly Owned Treatment Works (POTWs)  to relatively dry house-
 hold garbage. The  moisture content  of  the MPL  site  waste mate-
 rials likewise varied from free liquids in  ponds,   as found at
 the Saco Tannery Haste  Pits  site,  to the dry paniculate dusts
 of the Iron Bound Area dioxin sites.

     The  four most common material  types  found at Supertund
  sites  were  soils,  sludges,  municipal  solid  waste, and  free
  liquids. Soil contamination was  the result of both placement of
  the contaminant directly on the soil and the placement of  soil
  material over  a contaminated site,  as  would occur  in the clos-
  ing of  a  lagoon.  Sludges  of both  industrial  and municipal
  origin were co-deposited  with  soil  material  iff many cases. In
  addition,  sludges  were often found to be applied  to municipal
  solid wastes.   The defluidiration of the sludges led to contam-
  ination  of  other  materials.  Due to this mixing of  contaminated
  and  noncontaminated  materials,  contaminated  material   types
  found at NPL  sites cover a wide  range of  sizes and concentra-
  tions of contaminants.
                               -11-
                                                                                                                                      8       3

firm
OT » • —     2

           I?
-------
rv>
       Feedstock  preparation  equipment  developers  must  recognize
   this wide variation  in  sices  and concentrations when  designing
   systems to  provide  a uniform  feed material for a specific proc-
   ess.  Figure 2  is a  graphical  representation of  the range  of
   applicability  for physical processes  technologies  that could be
   useful  in  the  preparation  of  feedstock  for  mobile  on-site
   treatment technologies.

       The moisture content continuum of on-site materials is less
   often  realized than the size continuum,  but  it is  an integral
   feature  of  materials  found  at NPL  sites.  The combination of
   these  continuums can be represented by  a  ternary  diagram,  as
   shown  in  Figure 3.  The basic  material  types  have  indistinct
   boundaries  (in a physical sense) which  prohibit strict defini-
   tion  of  regimes  in the  diagram. The  central areas of  the  fields
0 have  specific physical descriptive properties, but  compositions
   near  the edges  could fit the general definitions  of two  or more
    field names.  As a  result, descriptions  in  the ROD  narratives
    for NPL  sites  are  not precise  enough  to  guide designers  of
    feedstock preparation equipment. For instance,  all  large mater-
    ials are often  described simply as "debris",  a  term of  no tech-
    nical significance to  equipment designers.  Information  Intended
    to serve as  • basis for design of feedstock preparation systems
    must  include the  range of particle sizes  found at the site.
    material fluid  contents,  and tne  chemical  composition  of both
    matrix and debris.

        The  characterization  of   a   site  purposely   averages  the
    observed  grain  sizes. The  use  of  equipment  to  handle these
    materials  is specific for a grain sire  range. The presence  of
    materials  with  properties outside of  the design basis is often
    the  cause  of equipment  failure.  The extreme ends  of the grain
    size  spectrum pose the greatest problems in equipment selection
    and  cause  most  problems in equipment operation.
                                  -13-
                                                                                                                                        ff
f
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 Jl
-------
IV)
     115-267J
                  FlguraX SUMnottura continuum of NPL •!!• iMMrtol*.
SUPERFUND SITE DEBRIS

    Debris is commonly defined  as  out-of-specification material
which cannot be handled by a given treatment  system and may.  in
fact, damage  the processing  equipment.  Debris defined in  this
sense (i.e., on the basis of  treatability)  does not necessarily
imply  a  separation  based  on  level  of  contamination.    For
instance,  oversized debris  may  or   may  not  require  remedial
treatment by alternate technologies or special  pretreatment.

    Specific  items  of  solid debris  and  contaminated  materials
found at  Super fund  sites vary considerably  in  nature,  but  most
can be grouped into the following nine general  categories:

    •    Cloth.

    •    Glass.

    •    Metals  (ferrous/nonferrous).

    •    Paper.

    •    Plastic.

    •    Rubber.

     •    Hood.

     •    Construction/demolition  materials    (e.g.,   concrete,
          brick,  asphalt).

     •     Electronic/electrical  devices.
                                                                                                                         -16-
-------
    These categories of debris  have  been defined on  the basis
of information obtained  from interviews  with various EPA Region
Superfund Site Managers;  EPA  Environmental  Response Team (ERT)
members;  EPA TAT, REM. and  FIT  consultants;  and  EPA-RREL Tech-
nical Project Managers,  for each of the various treatment tech-
nologies.  A detailed breakdown  of  specific  items found in each
debris category is presented in  Appendix A.

    In addition  to  this  wide  range of  debris  types,  the quan-
tity  of  debris  at  sites  also  varies  considerably.    It  was
"unofficially" estimated  in  the  above  survey that  debris at
sites varies on  a volumetric  basis from  less than 1 percent to
greater  than 80  percent.  The  larger volume  occurs  at sites
where demolition  debris  or sanitary landfill  wastes  have been
disposed-of along with hazardous materials.

    A preliminary  assessment  of each of the six mobile  on-site
treatment technologies was  conducted  to  determine  the  maximum
size  of  debris  and  material  that  could be  subjected  to the
treatment process.  An examination of  the six  mobile  treatment
technologies  discussed  herein  indicated  that  all could  gener-
ally  accept  1-in.  and  smaller materials.   There  is, however.
considerable variation in the acceptable  range of feed material
sizes  for  each  specific  technology.  For  instance,  within the
category  of   incineration,  fluidized-bed incineration requires
that  the feed particle size  be approximately  the  same  as the
bed  particle size  for  optimum  performance, while  rotary  kilns
may.  in  principle,  accept material  sizes up to the* kiln's  dia-
meter.   Since the feed size for a given  on-site  treatment  unit
must  be  tailored  to provide the  requisite particle  diameter,
debris is a  relative term.

    The  maximum  debris  size  for each technology, based  on this
preliminary  assessment, is  shown in Table 1.
                              -17-
 TABLE  I.   DEBRIS  SIZE  REQUIREMENTS FOR MOBILE  ON-SITE TREATMENT
Maximum debris size
Technology
1-2 inches
l/2-inch
effective 6 inches
l/4-inch
2 inches
l/4-inch
Biological Degradation
Chemical Treatment (K-Peg)
Incineration
Low-Temperature Desorption
Physical Treatment (Soil Hashing)
Solidification/Stabilization
    Debris  larger  than  the  maximum  allowable   size   must  be
segregated  from the feedstock  material and handled  separately.
This  oversized material  must  then  either be  treated  indepen-
dently  or  reduced in size in order to  meet the feedstock speci-
fications of the  on-site  treatment equipment.  A  common problem
encountered  at NPL sites is the  determination of  representative
average contamination  levels  on  large debris,   such as  stone,
wood  pallets,  automobiles, and  buildings.

    A common operational problem  in  on-site  remedial actions is
material management  to produce a uniform  feedstock  from unhomo-
geneous site  materials.   The preliminary  information  collected
on debris  indicates  that current handling  procedures at hazard-
ous waste  sites range  from  "elaborate  separation and recycling"
to "no separation".  Following  site remediation,  processed mate-
rial  and debris  is  either  1)  sent  for  ultimate disposal in  a
secure landfill;  2) decontaminated  to levels allowing disposal
 in a municipal  landfill; 3)  used as  material for  construction
 foundation bedding; 4) recycled as  a  recoverable  resource;  or
 S) "delisted"  on-site to a non-hazardous status.

    Historically, the selection of  material-handling practices
 has been determined by the following factors:
                                                                                                                    -IB-
-------
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Technology feedstock  requirement.

Type  of  contamination.

Type  of  debris   (size,   shape,  phase,   form.  Btu  and
recycling value).

Quantity of debris  (percentage by volume  or weight).

"Clean-up"   standards   or   target  levels.    (Federal.
state,  local, private).

Potential for decontamination  of the debris.
                                           A conciliation  of debris types  and  debris  handling opera-
                                       tions at 29 Superfund sites  is shown  in Table 2.

                                           Once  contaminated debris has  been  separated from  the  haz-
                                       ardous waste   material  undergoing  treatment, it  must  either  be
                                       disposed-of  in  a  secure  landfill,  stored  for  future   approved
                                       treatment  (i.e..  dioxin-contaminated material),  or  decontami-
                                       nated.   The  determination that  debris  is  contaminated is  gen-
                                       erally an  assumption that is made with little  or no analytical
                                       testing.   In  some   instances,  monitoring  devices,  such  as  an
                                       HNU/Organic Vapor Analyzer  (OVA) or  a Oeiger  counter  are  util-
                                       ized to  determine  If a particular material  is contaminated with
                                       volatile organic compounds or is radioactive.

                                           Decontamination  of  debris is possible for contaminants  that
                                       can be  recovered by aqueous washing,  either through solution or
                                       physical   separation.    Soluble   contaminants  can   be  washed,
                                       rinsed,  or otherwise surface-cleaned  or  removed  when associated
                                       contaminated   soil    is  cleaned   off.    Insoluble  and   inorganic
                                       (heavy metal) contaminated  fine soil  materials  can sometimes be
                                       successfully  separated  from  debris by high-pressure  washing or
                                       vibratory   separation,   allowing the   oversized   material   to be
                                                                       -19-
-------


Silt naae

IPA
Region

Najor
contaminant
Retomended
clean-up
alternative

Drhr t\
t»pf.

l>flir i v
hand! ing
                                               Solidi f ication
                                               Stabi.iiatton
                                               Biologic*)  Degradation
                                               (in tttu)
                                               Soil Washing
                                               Containment
?. NorgantOM. WV III



6. Southern M) III




9. Cryochem III
10. ShaMtr III

II. Montgomery Bros. 'Ill

12. Bridgeport Oil II

13. S.issvale III






Organics.
Metal 1


Organics




"Organics
PCBs

Organics

Oil
Mater

Oioiint.
K>>





Cjppinfl
Inn trjlion


Biologictl D«gr«)j-
tion
Incinrrat ion
Soil Wtthing
ISV
Work plan tlao«
Nethanol Citrtction

Off-lite di$pos«l

Incinerate lagoon
contents

Off-tile diipotal
in secure land-
fill and recycling




1 ires
Bel r iterators
Mood
Contret*
Cloth
Railroad ties
fla i 1 s . vood
Concrete, rocks


No debris
1 ires

OriMRS
Residential
Irash
wood. drtMs
lanks
Buildings
Buildings
Netals
Druas




Separation









Vibratory
aside
Off-site
disposal

Clean tanks

Oioiins to
secure land-
fill: steel
decontami-
nated and re-
cycled to
steel (ill
                                        I ABU 2.  (CONIINUCD)
EPA
Si le ntmt Region
14 . Alii ed^topk ins S





IS . B*i rd 4 HcGu i re 1



16. Hetaltec II
Aerosystexs, NJ
17. Syncon II





18. Oela.are City III


19. Drake Cnevical III


20. Col nun Evans IV
Major
contaminant

001.
lylene




Dioiins


ICt

Pesticides
PCBs.
Netjl t



PVC. ICl


Organics
and inor-
ganics
KBs
Recon«#nded
clean-up
alternative
.
Inc inerat ion
Off-site disposal





Oil-site disposal


Meat treatment
Rotary Dryer
Off-site
disposal




Off-site disposal
Reuse of recover-
able product
Off-site disposal


Incineration
Debr i s
types

Rails
Concrete pad
Blocks


t jnfc t
Mood buitdiigt
FUsonry


Ho debris
Large stones
Buildings
Unks
coils



No debris


Furniture
Piping

Hiscel laneous
0>br i s
hand! ing

taainated for
re-use;
Railroad ties.
concrete to
secure land-
fill
uood-snrrdded
and incinerated
Hasonryoff-site
disposal
Screening of
stones/rocks
Buildings and
tanhs-deconta*-
lulure use
Piping, etc.
-OH -si It
disposal
Reuse of
recoverable
product
Off-site
disposal

Separation
                                                                                  «ith shredding
                                                                                  and recycling
                                                                                  of metals
21.  Hollingsxorlh     IV      ICC.  metals    Vacuum extraction    None

22.  Hooray           IV      PCBs           Solidification       None
                                                                  224
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                          (PA     IUj*r
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r\>
 creosote-contaminated bayou can be  as effectively processed as
 the  naturally  organic-rich sediment  occurring  in  an  adjacent
 bayou.  Differences, such  as  increased adhesion  due to oil and
 grease  in  sand,  can normally be tolerated  by  process  equip-
 ment.   In  practice,  differences  occur, principally as a result
 of  operational  changes  caused  by  the  presence  of  hazardous
 material.

     Material processing  in  its  simplest form requires 1) exca-
 vation; 2)  movement  to the treatment  process; and 3) movement
 from  the  treatment process to  disposal or  further treatment.
 Each  of these operations  must  be  modified  to  accomodate  the
 presence of hazardous material.

.     When working with non-hazardous materials, equipment opera-
 tors  were  less constrained by  material  placement, permitting
 faster excavation with the sane equipment.   Mon-harardous mate-
 rials are generally excavated using  larger  equipment  that dis-
 charges materials in a less controlled fashion.  These observa-
 tions hold  true  within specific layers  and  at specific depths
 of excavation.

     Dust,   vapor,  and  airborne  emissions control  is virtually
 non-existent  at  non-hazardous  material  sites.   Health  and
 safety  concerns  related  to the contaminants' toxicity also led
 to  the  adoption of  slow  and careful  excavation  practices  at
 hazardous  material  sites.   In general,  health and safety con-
 cerns required continuous, careful  documentation of the proce-
 dures,  quantities,  and disposition of  materials throughout the
 on-site treatment process  at  hazardous material  sites,  thereby
 increasing costs greatly.
     Transport  of  hazardous  materials  to  treatment  units  was
 also  inherently complicated  by  the need  for  containment  of
 fugitive  dust  and  vapors.    Dust   control  measures,  such  as
 enclosed  conveyors, are seldom  used in  non-hazardous material
                              -25-
sites.   Non-hazardous  material  transport   included  free-form,
high-capacity.•   uncontrolled   stockpiling;   high-volume   bulk
transport  capabilities and  capacities;  and the use  of  high-
volume  processing  if  the  excavated  product  were  to  be used
on-site.

    On-site mobile  processing  equipment used on  hazardous mate-
rial   sites  generally  consists   of   small.    low-throughput
devices.   The small  size is  often the  result  of road limita-
tions and regulations.  The  detrimental effect  of small size on
cost  is compounded by  several  factors.   The  costs  of  set-up
time  and down-time while  awaiting permitting  and trial  opera-
tions  tend to be  the same  for small  and large  units,  but  cost
recovery  is  faster   using  larger units.   Once operational.
smaller  plants  have  higher unit  operating costs  per  ton  of
waste,   because  control  and  monitoring  instrumentation  costs
must  be amortized over a  longer  period.  The  latter  differences
in  operation  arise  principally  from regulatory  documentation
requirements.   Other  factors  contributing  to the high costs of
hazardous  waste  treatment  include insurance  against  potential
liability  and permit  limitations  on quantities and qualities of
materials  being processed.
                                                                                                                      -26-
-------
ro
IV)
                           SECTION 5

      FEEDSTOCK PREPARATION AND DEBRIS  HANDLING EQUIPMENT


EQUIPMENT REQUIREMENTS

    Mobile treatment technologies for hazardous waste sites are
essentially transportable  process plants  designed  to accept  a
specified  feedstream  with  well-defined  physical,  chemical,
thermal, and  flow-rate  characteristics.   However,  materials  at
uncontrolled hazardous waste  sites normally consist  of  a hap-
hazard  assortment  of  materials  having  unpredictable   sizes,
shapes,   compositions,  and  levels  of contamination.   Prior   to
treatment,  the  hazardous waste  and  contaminated materials may
be rearranged by excavation, sorting, transport,  and/or storage.

    Cm-site feedstock preparation systems essentially serve  as
the  interface  between a  wide spectrum  of materials recovered
from  the waste  site and  a  clearly defined  mobile treatment
feedstream.   It  is  possible,  in principle, to adapt  the  mobile
treatment system  to each  site treated,  rather  than to  use  a
feedstock  treatment  system.   However,  the wide  variation   in
feedstock  materials  and  the  inherent   inflexibility  of  the
treatment hardware  make  feedstock modification more  economical
and more feasible than treatment  system  modification.  The cur-
rent  technological  challenge of  mobilizing innovative systems
with fixed processing equipment is difficult- enough without the
further   complication  of  repeatedly reconfiguring the new tech-
nology to site-specific configurations.

    Although feedstock  preparation  requirements vary for each
treatment technology  and waste  site situation, the  basic on-
site  unit operations  used to produce  an  acceptable  feedstream
                                  -27-
are similar in most  cases.  Some common preprocessing unit oper-
ations include particle  size  reduction or  increase;  separation
of material types  and  compositions;  chemical or thermal adjust-
ment;   fluid-solid separation;  and  contaminant  concentration.
The operational  functions  of  this preprocessing  equipment and
the need  for durability,  reliability, maintainability,  mobil-
ity, and economy  are,  in many cases, quite similar to the  func-
tions and characteristics of  conventional  equipment.  Thus, most
feedstock preparation  operations  are based on analogous conven-
tional equipment,  such as  shredders,  crushers,  screens,   dewa-
tering filters, etc.

    Remedial  action  pretreatment  systems  have  unique require-
ments  that  may  necessitate  physical  changes  in  equipment  or
operational modifications.  These requirements include the fol-
lowing:

    •    Health,  safety,  and environmental  precautions  associ-
         ated with hazardous waste handling.

    •    Ease of  start-up and demobilization.

    •    Acceptable  operation in  urban/suburban areas.

    •    Ease  of  mobility to  remote,  relatively  inaccessible
         sites.

    •    Simultaneous  compatibility,  based on a  number  of para-
         meters,  with  a downstream process system.

These  unique  requirements  may  serve  as  a  basis  for   future
 research  and  development  (R&D)  activities  in  the  feedstock
preparation area.
                                                                                                                      -28-
-------
         Feedstock preparation technology will  likely become an area
     of  growing  interest  in the future,  due  to the expected evolu-
     tion of regulatory compliance requirements.  The impending land
     ban on disposal of hazardous material will increase the cost of
     waste disposal and will  require  modifications  of  current prac-
     tices  in  debris  disposal.   The  rising cost  of  contaminated-
     debris disposal will encourage more  on-site  treatment of mate-
     rial  now  classified  as debris.   The net  result will  be the
     inclusion  of  more  debris  processing  equipment  in   feedstock
     preparation and treatment systems.

         This  trend  toward  processing  more   debris  on-site  will
     increase the  quantity  and variety of feedstock  materials.   It
rv>   will  expand the  need  for a  "systems engineering"  approach to
££   remediating hazardous waste sites.   It  is  becoming  more impor-
     tant,  from  a  cost  standpoint,  not  to  "sub-optimize" designs
     based on  a set of  individual subsystems  (i.e.,  site prepara-
     tion,  excavation, transportation,  storage,  feedstock prepara-
     tion, waste treatment,  and disposal  of  treated materials) but
     rather to  optimize the  entire on-site  project over  its entire
     life cycle.  The  integration of  feedstock  preparation and  waste
     treatment  processes  is  of particular importance  to  this  "sys-
     tems engineering" approach.

         It was  found that  a fluid\zed-bed  incinerator  (Section  6)
     case  history illustrated the problem of optimizing the  overall
     feedstock preparation and  treatment  technology system.   In this
     case,  the  incinerator  and feeder could, -in  principle,  process
     most solids,  liquids, or gases.   However,  in  the  system  design,
     these  two  subsystems  were not  closely  matched  in  performance
     for changes in throughput rate as a  function  of grain size  and
     fluid  content.  Thus,   when  the  feedstock  material  had  out-of-
     specification  values for particle  size or  fluid  content,  the
                                   -29-
performance of  the feeder and reactor  varied  in different ways
and overall system performance was drastically  impaired.   Fur-
thermore,  in  the  incinerator  design,  little  room  was allowed
for the  feeder,  and the  small feed  unit  subsequently acquired
became the particle size limiting factor for the whole process.

TYPES AND CATEGORIES OF EQUIPMENT AVAILABLE

    In order  define the performance  requirements for  feedstock
preparation equipment, we  examined the feedstock specifications
for  some  widely   applicable  thermal, physical,  and biological
treatment  methods.  Comparison  was  then  made of  the required
feedstock  properties  with  the   site material  characteristics
presented  in  Section 4.   Specific waste  treatment  methods  an-
alyzed  included the  mobile  on-site treatment  technologies  of
incineration,  soils washing,  Low-Temperature  Thermal  Stripping
(LT ),   immobilization/fixation,  dechlorination,  and  biologi-
cal  degradation.    Thermal  treatment  technologies  investigated
included  rotary kiln  incinerators,  fluidized-bed incinerators,
and  multiple-hearth  incinerators.   The   incinerators  examined
were  capable  of treating  both solid  and  liquid materials.  Ex-
perience  with soils  washing  was  gathered  primarily  from  EPA
Mobile Soils  Hashing projects.   Low-Temperature Thermal  Strip-
ping experience was obtained through WESTON's corporate  experi-
ence with  the design,  construction,  and operation of the WESTON
Low-Temperature  Thermal Treatment  (LT3)  Unit.   Biological  de-
gradation  of  Superfund-related   materials  via  the  activated
sludge  process,   aerobic  lagoons  and  tanks,   composting,  and
trickling  filters  were also examined for feedstock preparation
requirements.

    The  basic support operations for  mobile  on-site  treatment
technologies,  as shown  in  Figure  4,  are excavation,  stockpiling.
                                                                                                                      -30-
-------
                       Excavation
rv>
rv>
                       Stockpiling
                       Conveying
Homogenization
                       Treatment
                  Rgur»4. Elements) unit* in fMdttock procmlng.
homogenization, conveying, and delivery  to the conversion proc-
essor.  Each technology requires a specific  input  size and com-
position to produce a  characteristic  product.  Therefore, mate-
rial  segregation  by  composition, morphology,  and size  is com-
monly employed  to preprocess the feed prior  to  the actual con-
version of the hazardous contaminant to a benign material.

Excavation Equipment

    The  processing cycle  generally  starts  with  feed material
excavation. The excavated  material  is transferred to  additional
processing equipment that  renders the material  relatively uni-
form  in  size  and  composition for the treatment stage. The exca-
vation stage produces a characteristic product depending on  the
method of  excavation,  the size of the excavation equipment,  the
physical properties  of each material  being  excavated,  and  the
relative amounts of each material.

    The choice  of  the  excavation method is primarily  determined
by  the  physical  properties  and  proportions  of  the  materials.
The physical  properties of  the  excavated materials are  largely
a  function of  the chemical components  of  the  material.    The
excavation  operation  may  or may  not change this  composition.
For example,  in the processing  of  wastes from  a typical waste
site,  the  segregation  of drums  and  other  large,  bulky  debris
from  soil  is   often  performed, essentially  producing two feed-
streams.   High water  contents will  lower  the  conesiveness  of
most  NPL site materials.   Thus,  excavation  with  a backhoe  or
clamshell  bucket  may  significantly  retain  only  drier,   more
solid aggregations and larger  particles,  with the wetter mate-
rial  remaining behind.

    The  strength  of  the  material must  be  considered  in  the
choice  of excavation  equipment.  Contaminated   water,  bedrock.
                                                                                                                      -32-
-------
f\>
OJ
o
laminated organic-rich  soils,  and  municipal  rubbish,  all  of
which  are  encountered  at  Superfund  sites,  require  different
types of excavation  equipment.

    Excavation equipment normally  operates  in  a  batch  mode,
removing a fixed amount of material  in  a  periodic  cycle.   Con-
tinuous excavation equipment (highway pavement  excavators)  may
be justified  at large, relatively homogenous sites.

    There are five general  types of excavation equipment avail-
able  for  use  by site  remediation  personnel,  to  move  soil,
sludge, or  sediment.  They are as follows:

    •    Backhoes

         -  Rubber-tired
         -  Tracked

    •    Front-end Loaders

         -  Rubber-tired
         -  Tracked
             Bulldozers
                                   \
        •    Cranes with drag-lines or clamshells

        •    Dredges

        Backhoes  are  the  most   common  equipment  for  excavating
    soils.   Backhoes  come  in various  sizes,  ranging  from  small
    Bobcat  units  to large  track-operated  power backhoes  that are
    capable of excavation of  several cubic yards at  one time.  The
    most  widely used  backhoe is  a rubber-tired tractor backhoe for
    the excavation of soils. The  small  Bobcat unit  is normally used
    in confined areas where the  normal rubber-tired  backhoe  cannot
                                 -33-
operate efficiently.   Larger track-operated  power backhoes are
normally  used where  large  quantities  of  material  and  depths
greater than 10 to 12 feet need to be excavated.

    Front-end  loaders  are typically utilized  for  the loading  of
vehicles or for the transfer of contaminated material to the on-
site treatment unit. The size of front-end loaders varies from 1
cubic yard  for the bucket on rubber-tired backhoes to  3.5  cubic
yards or  larger  on larger units. In certain instances,  front-end
loaders can be used for clearing or excavating materials.

    Bulldozers  are  normally  utilized  for  the  loosening and
extrication  of  large quantities  of  material.   In addition,  they
can be used to clear debris or low-growing vegetation.  Bulldoz-
ers vary  in size, availability, and range, from a small tractor-
type crawler-dozer to  large D-9 machines  with ripping  equipment
for  loosening compacted  materials or  bedrock.   The use of  bull-
dozers  is unusual on hazardous  waste sites because  they do not
have  lifting capability  and they tend to  mix contaminants  with
previously  uncontaminated material.

    Cranes  with  clamshells  or  drag-lines  are  typically utilized
for  the excavation  of  sludges, sediments, or  pliable  materials.
Cranes  are  used  only when the pond,  lagoon,  or water body is too
large  or  too deep to be excavated with a large power  hoe.  or in
instances when the liquid contents cannot be drained off  and the
solids  are  not pumpable.

    Dredges  are  utilized  at  sites  where the  surface  liquids
cannot  be removed and  the solids are pumpable.  There  are three
categories  of  dredges:   mechanical,   hydraulic,  and  pneumatic.
Descriptions  of   these   devices'   applications,   limitations,
 impacts,  and  relative  costs are discussed in  Boyer  et. al, Sep-
 tember   1987.  Dredges  vary  in size  from those  used  to clear
                                                                                                                       -34-
-------
harbors and  civecs to  small  portable units  used  in  ponds or
lagoons,  such as the Mud-Cat and the Electric Mega-Flump  (manu-
factured by Crisafulli  Pump).

Size Modification Equipment

    The separation  of  phases  is usually  the initial  task in
feedstock  preparation.   This  initial  processing  may  include
shredders  and  screens  and/or  direct  feed  into  the treatment
equipment.  The  second task  is  the  segregation  of materials
according  to size.   Over-  or  undersized material may be  commi-
nuted or  agglomerated,  respectively,  to  provide  properly  sized
feed material  for  the  conversion process.   Size reduction is
the more common process, but flocculation of  suspended  particu-
lates or  compaction of  low-density  substances  is  also used. The
selection  of  process  equipment   for  mobile  on-site treatment
systems  depends  on its  role  in  the  overall  site treatment
system.  The principal selection criterion is  appropriate  capac-
ity for the system's feed rate.   A  choice  between continuous or
batch processing must also be  made.  Since few models of excava-
tion equipment currently used on  hazardous  waste  sites  are con-
tinuous in nature, a firm requirement for continuous processing
rarely exists.   If  small-sized  continuous  process  equipment is
selected,   buffer  storage  is required for  batches of excavated
material.

    Review of  the  size  comminution equipment literature  indi-
cated that there is a  commercially available item of process
equipment  for every material identified  at  HPL sites. An  excel-
lent review  of  size-reduction  equipment for  4-in.  and  larger
particles  is provided  by Mayberry,  1983.   Equipment  identified
for  potential  use  in  feedstock  preparation  for  the treatment
technologies  studied  includes   shear  shredders,   ball  mills,
hammer mills and, potentially,  cannon  shredding.
                             -35-
    The  performance  required  of  size  reduction  equipment  is
primarily determined  by  the  feedstock  specifications  for the
mobile treatment unit.   Variables that must  be  addressed in the
proper selection  and  specification of  size reduction equipment
include the following:

    •    The ability of the  treatment process  to  accept metal-
         lic materials.

    •    The desirability  of size  comminution  of material  con-
         taminated only on its exterior surface.

    •    The  ability  of   the  treatment  process  equipment  to
         handle  high  quantities   of  a  potentially upsetting
         material  (e.g..  shredded  galvanized metal or flammable
         liquids fed to a fluidized-bed reactor).

    •    The ability of the  treatment process  to  accept stringy
         metallic wastes (e.g.,  wires, cables).

    •    Downstream feedstock  preparation equipment.

    •    The  potential  for  explosions  and  release  of  toxic
         materials within the  size reduction equipment.

    •    The  morphology  of  oversized  materials  (e.g.  platy,
         sheetlike, smooth,  rounded).

    •    The ease  of  cleaning and  decontamination during equip-
         ment breakdowns  and demobilization.

    Many kinds  of size  reduction equipment  are  used by the
 mining and chemical processing industries.  Specific equipment
 selection  often depends  on  material hardness.   For  large, hard
 materials  (i.e.,  rocks),  jaw  crushers and gyratory crushers, or
                               -36-
-------
heavy-duty impact  mills,  rotoc.  hammer,  ball,  or  cage mills are
commonly specified.   Roll crushers exist, but they tend to have
high wear  rates.   Shredders  are  available that  can comminute
almost any  solid  object  from automobiles to  I-beams.   Some of
the more  capable  developmental machines  in  the  Department of
Energy's  Idaho  laboratory  can crush virtually any component of
a nuclear waste container.  For softer  organic  materials, many
mobile shredders are available.

    If fine grinding  is  required  to  liberate  contamination  from
its debris  matrix,  many varieties of  physical  and  fluid mills
(ball. rod. hammer,  roll,  jet,  tumbling,  etc.) have  been  devel-
oped  for  chemical,  food,  mining, and  cement industries.   The
reader  is referred  to  the  literature  of these  industries  for
details (see Bibliography).

Separation Equipment

Phase Separations

    Separation  of materials  is a prime consideration  in feed-
stock  preparation.   Of  particular  concern  is the separation of
multiphase  materials.  The separation of water from  sludge,  -the
dewatering  of  sands  and  soils,  and the  concentration of  dis-
persed  contaminated  colloid* are frequently critical  problems
 at NPL  sites.

     Systems for phase separation of feed  slurries and  effluents
 from mobile treatment technologies can be  run as batch or  con-
 tinuous operations.  Provided that the  feed  material is  homoge-
 neous,  continuous process equipment can provide  excellent  serv-
 ice.   However, continuous processes have  high throughput rates,
 are more technically complex, and have high capital  costs.
                               -37-
In addition,  they require redundancy  in  process equipment, need
sophisticated control  systems,  generally have  high operational
costs, are susceptible to operator error, and may not be easily
transportable.  Process equipment  performance  in most continuous
operations has  been found to be specific  for  a  certain particle
density and  diameter,  particle size  distribution, and chemical
composition of  particles and fluids.

    Batch separation processes to treat  effluents are generally
simple, capitalizing  on the  settling of particles  by gravity.
Both continuous and batch processes are  used  extensively in the
water  and  wastewater  treatment  industries, where high volumes
of water must be  processed  at minimal costs.   Proper selection
of batch versus  continuous processes  is  determined by the spe-
cific  composition,  size, size  range,  and  distribution  of the
particles  that  need  to  be  separated,  and   the  feed  volume
required by the treatment process.

    Hazardous waste sites on the  NPL have  great  variability  in
types  of  soil  and  contaminated material.  This  suggests  that,
if process  equipment   is to  be used  repeatedly and transported
from  site  to  site,  two basic options  for  on-site processing
systems are available.

    The first option  is  to  obtain  continuous  processing equip-
ment  and to  provide a closely tailored material  feed by careful
preprocessing.  Arguments against  this option  are the additional
capital and  operational  preprocessing costs that will be  incur-
red, the greater probability  of processing  upsets, and the pos-
sible need to modify preprocessing equipment for  each site.

    The second option  is the use of  batch  processing equipment.
Small-volume portable tanks,  lined  bulk-material  trailers,   or
dedicated  tank  trucks  may be   considered for   use  as   batch
                                                                                                              -38-
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OJ
processing vessels. Arguments  against  this option are the pos-
sibilities  of  leakage  during  liquid  transport/storage  and
increased  processing   time.    Within   the   framework  of  these
options, the techniques of thickening and dewatering the efflu-
ent or feedstock are discussed  as follows.

    Thickening  of  the slurries  may  be  accomplished  through
gravity  segregation,  flocculation,  filtration, centrifugation,
and  straining.  Thickening  through  simple gravity-segregation
allows  particles  to settle  according to Stokes'  laws of sedi-
mentation.   Removal  of particles  down to   coarse-silt-size can
be rapidly  accomplished  by  this process.  Increasing  the resi-
dence time of the  fluid  in  the sedimentation  chamber  can effec-
tively  remove particle sizes  down to  3  microns,  provided that
the particles have  a  significantly higher  specific  gravity than
the water media.   Since  low-density  objects will  float, petro-
leum  adsorbed  onto fine-silt-and-clay-sized  fraction may give
the total particle  a  neutral or positive buoyancy. Segregation
through  flocculation  is possible  if  the particle has  positive
buoyancy. Neutrally buoyant particles will  not settle and must
be separated through  other  processes using size  differences  or
chemical affinities.

    Processing  equipment  alternatives designed  for  thickening
through  gravity-segregationI  are  batch settling  tanks,  unit
thickeners,  and tray  thickeners. These thickeners  are construc-
ted of  a variety  of  materials,  including   steel,  concrete,  and
plastic-lined earthern pits. For dilute  suspensions,  clarifiers
offer good  performance.   These clarifiers  include  rectangular,
circular, and  reactor clarifiers.  The  latter incorporates  the
mixing  and   flocculation  equipment  in a single tank.  Floccula-
tion  has proven successful in agglomerating  clay particles  in
order to enhance  settling.  The design of  the proper  flocculant
and chemical addition  is specific for each slurry to be treated.
                                      -39-
The  determination  of  the  precise  coagulant mix  is  normally
developed by a trial-and-error approach.  These  reactor clarifi-
ers  may be  operated such  that  the finished  water  is  passed
through sediment at  the  bottom of  the  tank to provide filtra-
tion of the pin floe, thereby polishing the effluent.

    Another  process used  in  the  separation  of  materials  for
mobile on-site treatment technologies  is  filtration.  Filtration
equipment, in  the generic  sense,  operates  in much  the same way
as  screens.  This  principle  is directly  applied in  filtration
via  inclined-wedge  wire  screens and micro screens.  Permutations
of this principle  permit rotation  of  the screens,  as  found  in
the  rotary-wedge  wire  screens. The combination of  wire screen-
ing  and screening  by layers  of particles themselves  is applied
in the  diatomite filters.  A variation on this  theme is centri-
fugal screen filters. Other  combinations  of processes  that may
be  applicable  to  feedstock  preparation  for mobile  treatment
technologies include wide-angle conical  screen  centrifugal fil-
ters and circular disk-membrane trap filters.

    Centrifugation,  in its simplest form, uses gravity enhance-
ment  to allow  particles to  settle according  to  Stokes'  law.
Centrifugation  can be applied as either  a  batch or continuous
process.   Applicable equipment identified  for  consideration  as
potential  feedstock  preparation   devices   includes  continuous
decanting  horizontal-screw centrifuges  and  screen-bowl continu-
ous  decanter  centrifuges.   Field  experience  with centrifuges
suggests that the highly abrasive material  that would be fed  to
the  centrifuges  will  cause  rapid  wear  and hence,  relatively
high maintenance costs.

    Commercial  centrifuges  tend  to be  continuous-flow devices
for  the separation of fine  particles.    They are often used  in
conjunction  with  internal filter  screens.   A  large  number  of
washing and back-flushing  cycles are possible with centrifugal
                              -40-
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uo
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separators.  Centrifuges  show best results in relatively stable.
carefully oriented platforms and  are  not tolerant  of  platform
motion;   therefore,  special  installation  and operational  care
must be taken in field operations.

    Filtration equipment  and filter media  are  available  in a
wide range  of  configurations.   For  very fine materials,  a pre-
coat is often used to:

    •    Provide an initial fine layer  on a screen coarser than
         the particle size.

    •    Provide a large  surface  area  that hinders blinding of
         the filter screen.

    Filtration equipment is available  in batch,  semi-batch,  and
continuous configurations.  Options include vacuum or pressure,
precoat,  table,  pan, continuous  disk,  plate-and-frame,   leaf,
cartridge, drum, edge shell, and  tubular.   Selection is princi-
pally based  on the characteristics of  the  bulk particles col-
lected  on  the media.  Vacuum filters  are  often used for  hard,
fine materials, including clays.  Plate-and-frame or shell fil-
ters tend  to be used for sludges, colloids, or slimes contain-
ing  viscous liquids.   The  unit  operation  of  expression  (com-
pression) can  be  used to  dewater  the resulting  filter cakes.   A
wide variety  of wash and  back-flushing cycles  are available  to
adapt filter  systems to  the specific  eccentricities  of a par-
ticular  site mixture.

    The  addition  of  chemical additives used in municipal  water
clarification  can  improve  the performance of  filtration  and
centrifugation equipment.  The use  of  chemical  additives  for
coagulation  and flocculation yields sludge-type materials  that
can be  dewatered through  conventional  dewatering techniques.
                                 -41-
    Dewatering systems  include  rotary vacuum  filters,  rotating
belt presses, and evaporators.  This  equipment is available in a
wide range of sizes and complexities.  The  simplest are lagoons
with  natural  evaporation.  Greater  efficiencies   are  obtained
through dewatering beds and evaporative-drying beds.  A combina-
tion  of  gravity and  pressure removal of  water is used  in the
most complex dewatering devices.

    Equipment  potentially  applicable  to   frequently  occurring
materials  and treatment  technologies used on  Superfund  sites
includes  the Carver  hydraulic  filter press,  the  Sparkler HRC
horizontal-plate  filter,  and portable vacuum-assisted dewater-
ing beds.

    Foams are produced  in  the processing of hazardous materials
in  the biologic,  soils washing,  and,  to some extent, neutrali-
zation  treatment  technologies.   These  foams  can  be  separated
through  the  judicious placement of underflow  weirs in the  proc-
ess  stream.  The equipment  utilized for this  operation  may  be
specifically  designed,  such  as  that  found  in  conventional
wastewater plant  "scum suckers",  or can be  quickly  fabricated
from  a holding tank  having drains below fluid  level. Equipment
similar  in design to conventional grease  traps should be able
to  remove significant  quantities  of the  foams produced by  on-
site  treatment technologies.

    Floating   of  fine,  hazardous-waste-rich  particles   offers
possibilities  as  a method for  contaminant  concentration.  During
soil  washing tests,  oily  material  washed from the  sands pro-
duced a  stiff  foam.  This foam could possibly be decanted  and
broken down  chemically to  reduce  its volume.

    The  operation  of  one  treatment  system,   the  mobile  soils
washer (NSW),  is   based entirely  on  liquid-solid  particle size
                                                                                                                      -42-
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rv>
    separators.  The MSW  technology produces  a fine suspended  sedi-
    ment  containing concentrated  contaminants,  and  a coarse  sedi-
    ment  which is  intended  to  be recycled  back to  the site.   The
    operating  principle  of  the MSW  is the  association of  organic
    contamination with the surfaces of  soil particles.   The  predomi-
    nance  of  surface  area is  on  smaller  silt  and  sand-grain-sized
    particles; hence, the  contaminants  are often concentrated  in  the
    fine-particle fraction.

    Physical Separations

        There  are  a number  of  alternative processes  Cor  separating
    debris  from contaminated materials that  do not  involve  phase
    separations.   These processes are  based  primarily on two  prin-
ts  ciples:  1)  "manual"  sorting,  with decisions  made by site  opera-
U1  tors  on larger items  that  cannot be processed  by the  treatment
    technology;  and 2) mechanical sorting  of solid materials  based
    on  differences  in  physical, chemical,  or  radioactive properties.
    There  is  a wide  variety  of  conventional  physical  separation
    equipment,  potentially  useful  for  feedstock  preparation,  that
    has not generally  been tried on  hazardous waste  sites. Many of
    these  are  used  for gangue ore separations in the mining industry.

        A  number of principles  now used in refuse-derived fuel (RDF)
    plant  equipment are prime candidates for future use  in  remedial
    actions.  An obvious  application  is separators  based on metallic
    properties (e.g.,  tramp-iron  removal  By  magnets or  feedstream
    scans  to halt  processing upon  detection of magnetic  or conduc-
    tivity  anomalies  in  non-metal   matrixes).  Another  potentially
    useful unit operation used  in RDF  plants is classification based
    on  terminal velocity  of  air jets  (e.g.,  for  paper and plastic
    removal from dense  solids).
                                  -43-
    Sieving can be  used in classifying dry  particulate solids,
although energy requirements may be  higher than  analogous par-
ticle size separations based on  terminal  velocities in liquids.
Sieving or  screening can  be performed  by  a  large number  of
devices  using  grizzly  bars  (still  or  vibrating);  revolving
screens (screens  that shake  or  vibrate  mechanically  or  elec-
trically); screens  that  oscillate,  reciprocate,  or gyrate; and
continuous  belt  screens.   Similarly,  solid  separators  exist
that work  on  a wide  variety  of  principles  and configurations.
Some  existing  commercial  separators  are   based  on  conical
screens;  continuous  belts  in  inclined troughs;  rotating rakes
on inclined tank  bottoms;  centrifuged jet bowls;  and  jets that
hinder settling.

    Other  solid  separations can  be accomplished by  jigging
(pulsing  solids through screens  in  liquids);  tabling (washing
solids  across  inclined  riffled pans);  and spiral concentration
(particle washing in spiral channels).   "Dense-media" (liquid-
solid suspensions) can be  used to  make solid particles separate
at specific density  points.  Many  wet and dry  magnetic separa-
tors,  of  various configurations,  are available for recovering
ferromagnetic  materials.   The same   concepts  can  be  used for
diamagnetic separations.  Commercial  separators based  on elec-
trostatic properties have also been  successfully used in  mining
operations.

    As  new, developmental  treatment  technologies mature,  field
trials  will   define  unacceptable   feedstock   characteristics.
Future  technology developers should consider  the possible use
of  conventional  materials  handling  equipment,  such  as   those
referenced previously,  that can make separations  based   on the
specific  feedstock  physical properties to which  the treatment
technology is sensitive.
                                                                                                                      -44-
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    Chemical Treatment Equipment
(V)
(JO
    Neutralization  of  waste  matrixes  is  a  common  chemical
operation for feedstock preparation.  However,  many other chemi-
cal treatment operations presently used in the chemical, paper,
and petroleum  industries  could be  applied in  modifying feed-
stock or in  concentrating fluid contaminants.  Conventional com-
mercial  equipment  for  leaching,  percolation,  sorption,  ion
exchange, extraction,  adsorbtion,  absorption,  or precipitation,
offers the possibility of  recovering  or concentrating contami-
nants for subsequent treatment by mobile  systems. As new treat-
ment technologies evolve,  the development of ancillary chemical
pretreatment  systems could  serve  to  "fine-tune"  their effec-
tiveness.
     Heat Transfer  Equipment

         A  number  of  new  thermal  treatment  systems  (e.g.,  low-
     temperature   vaporizers,    in   situ    techniques,    advance
     incinerators,  f luidized-bed systems)  are now under development.
     The  economics  of  mobile thermal  treatment systems  are often
     dependent on  the  high cost  of  "mobile" energy,  especially in
     feedstocks  with  high  water  content.  There  may  be  future
     opportunities   for  thermal  recovery   systems   (recuperation,
     regenerators,   etc.)   to   effect   economies   by  pretreating
     feedstock streams.
                                  -45-
                                                                                                                    SECTION 6
                                                                                            FEED PREPARATION FOR SELECTED MOBILE ON-SITE TECHNOLIGIES
    Treatment processes  that were  examined in this  report  for
possible constraints on the  feed  input  include physical, chemi-
cal,  and  biological processes.   The constraints were found  to
be primarily operational  concerns and  closely related economic
concerns.   The following  section  briefly describes six specific
processes  and  their potential  constraints  on the  handling  of
Superfund-type materials.   Included in  this  review is informa-
tion on the  types  of waste that  have  been used  with  the  tech-
nology; key  process equipment;   specific  feedstock preparation
requirements; staff  and training  requirements;  and limitations
of  the  equipment,  including  site-selection  constraints  and
availability.

DESCRIPTIONS OF SELECTED PROCESSES

BIOLOGICAL TREATMENT - THE ACTIVATED SLUDGE PROCESS

I.Technology Category
    The activated  sludge  process is a  biological treatment pro-
    cess  involving  wastewater  mixed  with  an  active  mass  of
    microorganisms  in  a chamber providing  optimum  growth condi-
    tions  (activated sludge).  This process  is  used  to  stabi-
    lize biodegradable organic matter under aerobic conditions.
    The basic process flow diagram is shown in Figure  5.
                                                                                     2.Type of Waste
                                                                                         Activated sludge treatment  is  used to reduce concentrations
                                                                                         of a wide  variety  of  organic  compounds,  including  many
                                                                                         toxic  and  hazardous  compounds.    It  is  widely  used  for
                                                                                                                   -46-
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   Treatment Process
                                   Function
Pretreatment
       Influent
                              Removes Roots, Rags, Cans and Large
                              Debris (Haul to a Landfill, or < Possible
                              Grind and Return to Plant Flow)
                              Removes Sand and Gravel
                              (Haul to Landfill)
                              Freshens Wastewater
                              and Helps Remove OH
                              Measures and Records Flow
                              Removes SMtoabM and
                              Floatable Materials
                              Treats Solids Removed
                              by Other Processes
                              Removes Suspended
                              and Dissolved Solids
        Effluent
          Figures. Activated sludge proc*** flow diagram.
    treating municipal and  industrial wastewater;  specifically,
    reducing  CODs  and BODs  in wastewater with  organic  concen-
    trations  up  to  10,000  mg/1  BODs.   It  is  also  used  for
    effectively  treating groundwater with  low concentrations of
    organics.

3.   Company Name,  Phone Number. Contact
    a)   Detox.  Inc.,  (513) 433-7394,  Evan Nyer
    b)   Polytac Corporation,  (215)  264-8740, David  Declement
    c)   Zimpso,  Inc., (715) 359-7211, J. R. Nicholson

4.   Key Equipment
    a)   Aeration chamber (constructed tank or earthen pit).
    b)   Air  supply  equipment  (blower  or  mechanical  surface
         aerators).
    c)   Secondary clarifier.
    d)   Sludge  recycling pump.

5.   Process Capacity and Rate
    Available  mobile  system   hydraulic  capacity  ranges   from
    7,000  gallons per  day  (gpd)  to  over 50,000 gpd.   An acti-
    vated  sludge  system  using high-purity oxygen  is well-suited
    to  mobile   treatment   applications   because  the  high  02
    efficiency   allows  the  use  of   smaller  reactors,  shorter
    detention  time,  and reduced power consumption   compared to
    activated sludge processes using atmospheric air.

6   Process  Residues
    Process  residuals  from  activated  sludge treatment of  leach-
    ate include  the following:

    a)   Waste   activated sludge containing high  concentrations
         of  metals and refractory organics that were present  in
         the wastewater.
                                                                                                                  -48-
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        b)   Air  emissions  of  volatile organic  compounds  that  are
             stripped from the waste during aeration.

        Sludge  will  require dewatering and nay  be  shipped  off-site
        for  disposal via  a  further  treatment or disposal  facility.
        If  the sludge  is hazardous,  it  must be  disposed-of  in  a
        RCRA-approved manner.  If the  sludge  is  not hazardous,  dis-
        posal should conform with state sludge disposal  guidelines.
IjO
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7.   Process Effectiveness
    Very high  (99  percent)  removal  efficiency  for many  non-
    halogenated organics  can be  achieved by  activated sludge
    treatment.

8.   Feedstock Preparation  Requirements
    Since  the  biomass  is  susceptible to  poisoning  by heavy
    metals and halogenated  organics,  pretreatment  using physi-
    cal/chemical   treatment   units  is  necessary  in  order  to
    remove these  compounds,  if present in the wastewater, prior
    to  activated  sludge  treatment.    Grit  removal  and coarse
    screening are used to  prevent damage to rotors and pumps.

9.   Staff Training Requirements
    The activated sludge  treatment process requires  the control
    of various environmental  parameters  such  as dissolved oxy-
    gen, pH,  nutrients,  alkalinity,  and  suspended  solids.   Due
    to  this  multi-parameter  control,  the process  has  a high
    level  of  operational  complexity  but 'utilizes-  established
    techniques  and  training.   Operators responsible  for  the
    system would require  appropriate  training.  'Maintenance  and
    operation  of  mechanical  equipment  is  important,  and  the
    chemical,  biological,  and physical  characteristics of  the
    process must be  understood.  Close operating tolerances  are
    required to  achieve the  99 percent  removal rate,  but  this
    is an  achievable goal.
                              -49-
10.  Manpower  Requirements
    Usually,   one  operator  is  sufficient  for  operating  the
    mobile activated  sludge treatment  system.    System  mainte-
    nance will require additional skilled labor.

11.  Process Limitations/Constraints
    The  following  are  some of  the  drawbacks  associated with
    activated sludge treatment  of hazardous waste:

    a)   The  reliability  of the process  is  adversely affected
         by "shock" loads  of toxics.   Feed-equalization proces-
         ses are critical for small units.

    b)   Slow  start-up  time (on the  order of  days  to   weeks)
         because  the  organisms  must  become acclimated  to the
         wastes.

    c)   Higher detention time for complex  wastes.

    d)   The necessity for  constant, skilled attendance.

    e)   Production of relatively high volumes  of sludge.

12. Equipment Mobility
    Mobile  biological  reactors are  relatively  simple  systems
    and  are  readily  transportable  on standard  flat-bed  trail-
    ers.   The site may  lend itself  to in  situ treatment  if  the
    waste materials are  principally  lagoonal  waters.
                                                                                         13.  Site  Preparation Requirements
                                                                                             Currently available units require an  area  of 12-ft-by-40-ft
                                                                                             (floor  space).   Site  preparation will  involve  provisions
                                                                                             for  transporting  contaminated  water  to  the  unit  and  for
                                                                                             transporting  effluent  from  the  unit.    Properly  graded
                                                                                             access  roads will be required.
                                                                                                                      -50-
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14.  Time  Requirements/Constraints
    Activated  sludge treatment system  requires  3  to 4  days  to
    set  up the equipment on-site and  to  put  it  into mechanical
    operation.   The plant must  be  operated  for a  time before
    the  biological  processes  obtain sufficient development  to
    effectively degrade the waste materials.

15.  Health and Safety Requirements
    As with every  other  treatment  process resulting in hazard-
    ous   materials,  operating  personnel  should  be  extremely
    careful in  handling the  process  residuals.  This   includes
    wearing proper protective  equipment.   Loss  of  volatile
    organics  from the  biological treatment process may generate
    localized  air  pollution  and a  potential health hazard  to
    field personnel.  Vapor  containment covers could be used to
    mitigate these emissions by  passing the spent gases through
    activated  carbon.   The  high-purity O2 treatment  system is
    equipped  with  hydrocarbon  analyzers  and  control  systems
    that   deactivate the  system  when  high   concentrations  of
    volatiles  are detected in the  wastewater.   This eliminates
    a potential   fire  hazard  associated  with  low flash-point
    compounds.

16.  Utility Requirements
    a)   Electric power  for pumps and aeration
    b)   Water source  for housekeeping needs

17.  Permitting Requirements
    Mobile activated sludge treatment  is  a fully  commercialized
    and proven system.   According to the  vendor (Zimpso),  aver-
    age time required  for  approval  of the unit by Federal  and
    state  agencies is  about  4  to  6 weeks.   Compliance with
    regulatory requirements  is required for  both  wastewater  and
    air (VOC)  discharges.
                             -51-
18  Estimated Costs
    Costs for  various  sizes  of  conventional  activated  sludge
    systems,   consisting   of   an   aeration  tank  with  a  6-hr.
    retention time;  a  mixed-liquor  suspended  solids  concentra-
    tion of  2000 mg/1;   a  secondary  clarifier;   and a  sludge
    recycling  pump,  for  treating  leachate  with  a  COD  con-
    centration of 10,000  mg/1,  are as  follows:
         Size, gpm            25          50       100
         Capital  Cost    $137,000     183,000   242.000
         O&M COSt/Yr.    t  9,000      12,000    15.000

19.  Number  of Systems  available
    Zimpso  has  one  mobile  unit   (capacity 18.000 gpd  max.)  in
    operation, which is a bio-physical  system  using the adsorp-
    tive capacity  of   powdered  activated  carbon  in conjunction
    with biological  treatment in a single step.

    Polytac has five mobile units in  operation.   The process  is
    » hybrid  of  several  biological  treatment  schemes consisting
    of assorted aerated/submerged fixed-film reactors.

CHEMICAL TREATMENT - DECHLORINATION

1.  Technology Category
    Dechlorination  is  a  chemical treatment  technology in which
    chlorine  is  chemically  removed   from chlorinated  organic
    compounds  such  as  polychlorinated   biphenyls   (PCBs)   and
    dioxin using a  reagent  whose structure  contains  sodium  (or
    other  alkali  metals)  combined  with  polyethylene  glycol
    (PEG).

2.  Type of Waste
    Dechlorination  equipment   is  commercially  available   for
    treating  organic   fluids  contaminated with  PCBs.   such  as
    power transformer  oils.   It  is being  applied to  PCB-contam-
    inated soils.
                                                                                                                 -52-
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  3.  Company. Contact, Phone Number
           Chemical Waste Management,  Peter  Daley,  (312)  841-8360
           PPM Inc., David Klones,  (913)  621-4206
           Sunohio, Tom Smith, (216) 452-0837

  4.  Key Equipment
           Reactor vessel
           Chemical storage tanks
           Chemical feed pumps
           Dual filter beds

  5.  Process Capacity and Throughput Rate
      The  capacity of available  systems  ranges  from  4,000  to
r\j    10,000  gpd,  based  on treatment of PCB-contaminated trans-
o    former oils.

  6.  Process Residues
      Residues   produced   include   inorganic   salts  (especially
      sodium  and potassium chlorides),  or  sulfates,  plus insol-
      uble  polymers,   all  of which  are  less toxic  than the ori-
      ginal contaminants, but which may  still  require disposal in
      secured  landfills.   Occasionally,  the   presence  of  heavy
      metals necessitates separate  treatment prior to disposal.
   7.   Process  Effectiveness
                                   \
       Over 99  percent  destruction efficiency has  been achieved
       with this technology for  PCBs in liquids  and soils.

       Feedstock Preparation Requirements
       Transformer oils  do  not  normally require special pretreat-
       ment.  Contaminated soils  require dewatering  to reduce  the
       deleterious effect  of moisture on  reaction  rates.    Soils
       must be slurried in order for this process to  be effective.
                                -53-
9 .   Staff Training Retirements
    This  process's   simple   operation  and   low  maintenance
    requirements preclude the  need  for  specially trained  opera-
    tors.

10.  Manpower Requirements
    Two operators per  shift,  or 4,160 man-hours  per  year for  a
    260-day operating year.

11.  Process Limitations/Constraints
    Matrix material must  be 1/4-in.  or less  in  size to  ensure
    contact with the reagent.

12.  Equipment Mobility
    Trailer-mounted  dechlorination  equipment  requires   minimal
    dismantling and reassembly  for site relocation.

13.  Site Preparation Requirements
    with properly graded access  roads,  and a required plan  area
    of  50   square   feet,   site  preparation   requirements   are
    minimal.

14.  Implementation/Lead Time Requirements
         Permit approval: 2 months  (average)
         Authorization to start-up duration:  1  month
         On-site testing: 1 week

15.  Health and Safety Requirements
    Level C safety protocols.
                                                                                                                      -54-
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16.  Utilities
    Clean water  and  power  are  required.

17.  Permitting Requirements
    As  a  fully  commercialized  and  proven  process,   mobile
    dechlorination should present  no difficulty in obtaining  a
    Federal permit,  and  local  acceptance should  then  follow.
    The  PCB  concentration   of  treated   oils  is  less  than  2
    mg/L/L; thus, they are considered PCB-free.

18.  Estimated Costs
    Costs  are  unavailable at present, but  is is  expected  that
    they will be comparable to  incineration  for  concentrations
    of  5.000  to 7,500 mq/L  and significantly less than incin-
    eration for  levels of 0  to 5,000 mq/L.

19. Number of Systems Available
    At   present,  only   one  mobile  dechlorination   unit  is
    available,  from Chemical Waste Management.

CHEMICAL TREATMENT  - NEUTRALIZATION

 1.  Technology  Category
    Neutralization    is   a   chemical   treatment    technology
    consisting  of  adding acid V>r base  to  a waste in order  to
    eliminate  excess  causticity   or   acidity,   bringing  the
     resultant  pH  to  within   a  prescribed  "neutral"   range.
    Neutralization  can  be  used  as  a  final waste  treatment
     process,  or  as  a pretreatment  process  to prepare  a  waste
     stream  for  further   treatment.    Neutralization  is   also
     applied  to  processes   that  render  a   hazardous  material
     non-hazardous.   Neutralization  is often  applied  to cyanide-
     containing  solutions  to  prevent  accidental  releases  of
     cyanide gas.
                               -55-
2.  Type of Haste
    Neutralization  is  used  on  organic  and  inorganic  waste
    streams including  sludges,  slurries, spent  acid  and alkali
    wastes, and groundwater.

3.  Company Name, Phone Number,  Contact
    a)   Chemical Haste Management,  (312) 841-8360, Peter Darley

    b)   Envirochem Haste  Management Services,  (919)  469-8490,
         Jerry Deakle

    c)   Rexnard C.R.I.C.,  (414) 643-2762, Richard Osantowski

    d)   Research Triangle Institute

4.  Key Equipment
    a)   Chemical feed system.

    b)   Rapid-mixing  tank  or,   for  rapidly  reacting  reagents.
         in-line mixing.

    c)   Adequate  and  properly maintained  pH instrumentation,
         either  for  single  monitoring of manual  systems or for
         complex automatically controlled systems.

    d)   Adequate  and  properly  maintained  indication  or moni-
         toring system for hazardous material concentrations.

5.  Process Capacity and Rate
    Available  system  capacity  ranges  from  1500  gpd   to  over
    100,000 gpd.

6.  Process Residues
    Neutralization  of  hazardous  wastes  has  the  potential  of
    producing  air  emissions.   Toxic gases  such as   ammonia,
    hydrogen sulfide,  and  hydrogen  cyanide  may  be  released if
                              -56-
-------
       wastes  are  not  mixed  slowly  oc  analyzed  for  potential
       adverse  reactions.   Neutralization  may cause  precipitation
       and may  result  in significant quantities  of sludge.   Sludge
       volumes  produced  by neutralization  of  soils  and  sludges
       depend   on  the  characteristics  of  the  waste   and  the
       neutralization  chemicals.   Additional  processing  of  the
       sludge  either  on- or  off-site  may  be required  in order to
       meet applicable regulatory requirements for disposal.

    7.  Process  Effectiveness
       Relatively  high   (95  percent)   process  efficiency  can  be
       achieved with neutralization technology.

ro   8.  Feedstock Preparation  Requirements
f\>      Feedstock preparation  for  soils and  sludges  would consist
       of segregating  debris  using a vibrating screen.   Additional
       processing through homogenization with drag-lines and back-
       hoes is often  undertaken.
    9.  staff Training Requirements
        Neutralization falls  into  two categories - manual  chemical
        addition and  monitoring,  and completely automated  systems.
        In  both cases.  pH  monitoring  instruments must be  relied
        upon  to judge  the  adequacy  of  treatment.   pH  monitoring
        instruments   require  careful,   knowledgeable  maintenance.
        Appropriate operator training would be  required to  ensure
        good  long-term operations.

     10. Manpower Requirements
        This   technology   could,   in  theory,  be  operated  by  one
        skilled operator.   Sizing of the equipment to the volume of
        material  to be treated  often dictates  several operational
        personnel  be  active on-site.  Daily duties include:
        •    Inspection and maintenance of pH  instruments.
        •    Chemical solution make-up, where  applicable.
                                   -Si-
ll .  Process  Limitations/Constraints
    Neutralization may  not  be effective  for  spent  acid  and
    alkali  wastes  with  pH between  4.0  and 9.0.   Solids  and
    sludges  may  require excessive  dosage of  chemicals due  to
    the difficulty of  achieving complete mixing  and  the poten-
    tially high buffer  capacity of  solid phases.

12.  Equipment  Mobility
    Requires minimal  amount of  dismounting and  reassembly for
    moving.  Most equipment is  either truck- or  skid-mounted.

13.  Site Preparation  Requirements
    Minimal  site  preparation.   In  many cases,  properly graded
    access  roads will be sufficient.
14.  Time Requirements/Constraints
    Equipment with  nominal capacity  is  available  on  a  short-
    term basis;  that  is,  less  than one  week.   Emergency meas-
    ures may require short-term use of readily available equip-
    ment or  reagents while  awaiting  the  long-term  equipment.
    For  example,  a rapidly  installed  caustic-soda  feed system
    might  be used  until  receipt  and  installation  of  a  more
    economical lime neutralization system.

15.  Health and Safety Requirements
    Due to the corrosive nature of neutralizing  agents and the
    possibility  of  toxic  gas  emissions,  the  process should be
    controlled from a remote  location,  if possible.   Feed tanks
    should  be  totally  enclosed  to   prevent  escape  of  acid
    fumes.   Adequate mixing  should be  provided  to  disperse the
    heat of  reaction if  wastes being treated are concentrated.
    Personnel involved in  the  handling of neutralization agents
    should  use  proper   protective equipment.    Worker  contact
    with corrosive  neutralizing  agents should be  minimized by
    using remote control.
                              -58-
-------
        16.   Utility Requirements
             a)  Electric  power  {or pumping and mixing of wastes.
             b)  Hater source for preparation of  neutralizing  solutions.
        17.
        18.
rv,
.fc
OJ
Permitting Requirements
The mobile  neutralization technology  is  a  fully  commer-
cialized  and  proven  system.   The  process  falls  within
existing regulatory guidelines.  Monitoring  systems gener-
ally must be approved by governing agencies.
Estimated Costs
Costs of  a  neutralization  system consisting of an agitated
tank  with a  3-min.  retention  time:  a  metering pump  for
acid or caustic  addition;  and a pH control loop and valve.
for treating  leachate with a pH of 3.4, are as follows:
             Capital Costs
             Operation and
             Maintenance Costs
                          S1SO.OOO for a 3.000-gpd system
                          f230.000 for a 22.000-gpd system
                          Including instrumentation
                          $0.07/g»l for a 3.000-gpd system
                          $0.03/gal for a 22.000-gpd system
             (Source;  Superfund  Treatment   Technologies   -  A  Vendor
             Inventory, EPA. 1986)
                                       •(
        PHYSICAL TREATMENT - SOIL WASHIKQ

        1.   Technology Category
             Soil washing  is  defined as a physical treatment technology
             in which contaminants  are extracted from a sludge or soil
             matrix  using  a liquid  as  the washing solution.  The spent
             washing  solution  is  then treated  to remove  the contami-
             nants  via a  conventional wastewater  treatment system.   A
             typical  soil  washing processing  flow diagram  is  shown   in
             Figure 6.
                                      -39-
t
m
t*
IT
5
                                                                                   g
                                                                      s
                                                                                                                         fl
                                      if
                                                                                                                   1C
                                                                                                                   «>s
-------
2.   Type of Waste
     Soil washing is suitable for soils contaminated with heavy
     metals, aromatic  hydrocarbons,  oily compounds,  PCBs,  and
     organic bromine compounds.

3.   Company Name.  Phone  Number,  Contact
     a)   Lee Strangio  and  Associates
     b)   Roy F. Weston.  Inc.. (215) 692-3030. James Nash, Alan
          Tamm
     d>   Biotrell
     e)   Charles Castle. EPA Region v,  (312)  539-2318
     f)   Hick Morgan.  EPA Region IX,  (916) 243-5831

4.   Key Equipment
     Countercurrent extraction equipment.
     Process Capacity and Rate
     The processing  rate of the  system  ranges  from 2.3 to  3.8
     rn   hr  (81-134  ft /hr).   The  actual  processing  rate  is
     established by  the  liquid treatment  capacity  of  the auxil-
     iary  mobile equipment  (i.e..  activated  carbon  treatment
     facilities,  flocculation/sedlmentation  chambers)  that  is
     required to process the wastewater for recycling.

     Process Residues
     Soil  washing  can  remove  contaminants from  coarse  mate-
     rials.   The effluents  of  the  process include- the  clean
     coarse  fraction.   A  foam  by-product is occasionally pro-
     duced, but  it varies due to  contaminants and  process  chem-
     istry.   Soil washing/extraction  yields  a hazardous residue
     consisting  of  a fine-particle sludge containing  the con-
     taminants.  This  sludge  contains a high percentage of clay
     particles  and  organic  soil components.   The  amount  of
     sludge  produced depends  on  a)  the composition of the soil;
     and b)  the  type of  purification  process used  for  the  spent
     extracting  liquid.
                              -61-
    Further  processing of  the  sludge  involves  either  trans-
    porting  it  to  a  controlled  disposal  site for  chemical/
    thermal  treatment or  treating  it  on-site  (via  incinera-
    tion,  chemical  oxidation,  or hydrolysis)  to destroy the
    contaminants.

    Wastewater  generated from mobile  soil washing  systems may
    require  further  treatment  before  ultimate  discharge  to
    municipal  sewer systems or off-site drainage systems.

7.    Process  Effectiveness
     Removal  efficiency  for mobile soil  washing technology has
     been demonstrated to be about 90 percent.

8.    Feedstock  Preparation Requirements
     a)   Segregation  of  large  debris  (wood,  rocks,  boulders,
          etc.) using a vibrating screen.

     b)   Breakdown  of  the  clay  fraction  of  the   soil   into
          treatable sizes by:

          1)    freezing  or   drying  combined  with   impact   or
               crushing techniques.

          2)   chemical   disaggregation    via   ionic    charge
               neutralization.
9.   Staff Training Requirements
     The  operators  responsible  for  the  entire  system  would
     require  special  training.  This  results  from  the  process
     having  a  high  level   of   operational   complexity.   This
     complexity  originates   from  the  multistage  soil  washing
     operation  and the variable  treatment requirements  for the
     contaminated  aqueous extracting agents.
                              -62-
-------
r\j
  10.  Manpower Requirements
      WESTON  has  successfully  operated  a  batch  soil  washing
      operation on a small site that required a  skilled operator
      and  assistant.   Operation  of the  prototype soils  washer
      developed by the EPA required six semiskilled personnel.

 11.   Process Limitations/Constraints
      High weight percentages  of  silt  or  clay in the soil mate-
      rial interfere with the  solid/liquid separation subsequent
      to the washing  phase,  complicating  effluent  liquor  treat-
      ment  requirements.   Laboratory   and  pilot-scale  testing
      would be necessary  to  determine  feasibility of  the soil
      washing system and  the  effect of  the clay/silt  content  on
      the  wastewater treatment  requirements.

 12.   Equipment Mobility
      The  equipment used in the system  is  skid-mounted,  designed
      for   transport   on   a   drop-deck   trailer   with  equipment
      installed  on  level  ground   for   operation.   The  typical
      overall  dimensions  are:  32  ft long, 8  ft  wide,  and 8  ft
      high.  The typical empty  weight is 14,000  Ibs.  Operations
      are  often scaled for addressing the volume of material  to
      be treated.
                               \
13.  Site Preparation Requirements
     Site preparation requirements  are.minimal.  In many cases,
     properly graded access roads  will  suffice.

14.   Time Requirements/Constraints   (permitting,  site  prepara-
     tion, etc.)

15.   Health and Safety Requirements
     Hazards  associated with  this  process  are minimal.   Person-
     nel   involved  in  acid   handling  (washing  fluid)  would
     require  training  and use  of   protective  gear.   Excavation
                             -63-
     and processing of  the soils must be performed by  personnel
     wearing appropriate safety gear.

16.  Utility Requirements
     Electricity  for  pumping  and mixing  of soil  slurry and  a
     portable water source for preparing the washing  fluid  and
     for rinsing the solids are required at  the  site.

17.  Permitting Requirements
     This  technology  has  not  been  fully  commercialized,   and
     regulatory  guidelines/performance standards  have not  been
     developed for it.

18.  Estimated Costs
     The following are  the estimated costs  for  the treatment of
     soils contaminated with heavy metals only:
          Capital Cost    -  $40/ton
          Operation 6  Maintenance Cost - $80/ton
     (Source: Interim Technical Report  -  Heavy-Metal  Contamin-
     ated Soil Treatment Conceptual  Development by WESTON,  Feb.
     1987)
            >
THERMAL TREATMENT - ROTARY KILN INCINERATION

1.   Technology Category
     Rotary  kiln  incinerators  are  thermal treatment  systems
     utilizing a  horizontal  rotary kiln  (cylindrical,  refrac-
     tory-lined shell) as  the  primary furnace configuration for
     combustion of  solid and  liquid wastes.  Typical  operating
     parameters are:
          Temperature:   1SOO°F to 3000°F
          Residence Time:  seconds for gasses;  up to  hours  for
          solids.  A  typical  process  flow  diagram  is shown  in
          Figure 7.
                                                                                                                      -64-
-------
f>0
-Cr
ON
                                                 Size/Phase
                                                 Segregation
      1S-267d
                       Figure 7. Rotary kiln procM* flow diagram.
                                                                                              Type  of  Waste
                                                                                              Rotary kilns can handle solid, liquid,  and  gaseous organic
                                                                                              wastes.   Incineration of solids  and  liquids,  independently
                                                                                              or  in combination,  is easily  achieved.  Hazardous  wastes
                                                                                              that   have  been  treated  in   rotary  kilns  include  PCBs,
                                                                                              dioxins, polyvinyl chloride (PVC) wastes, and pesticides.
                                                                                              Company Name,  Phone Number, Contact
                                                                                              a)    ENSCO Environmental  Services,
                                                                                                   McCormick
                                     (615)  794-1351, Robert
b)   Winston  Technology,  Inc..  (305)  978-1300,  Patrick
     Philips

c)   Roy F. Weston, Inc., (215) 692-3030, John Noland

d)   IT Corp., (213) 378-9933

Key Equipment
a)   Solids feed system.
b)   Rotary kiln.
c)   Afterburner (secondary combustion chamber).
d)   Air pollution control units.
e)   Process stack.

Process Capacity and Rate
Available  thermal  capacity  of mobile  rotary kiln systems
ranges from  8  to over 45 million Btus per  hour.   At  pre-
sent,  mobile  rotary  kiln  systems  have   capacities   for
treating  up to  10,000  Ibs/hr  of solids  and up  to  3,000
Ibs/hr of  liquids.

Process Residues
Mobile  rotary  kiln  incineration  systems  produce  solid,
liquid,   and  gaseous   residues   which  may  include   the
following:
                                                                                                                       -66-
-------
         a)   Bottom ash/soil
         b)   Fly ash
         c)   Scrubber liquor
         d)   Off-gasses
     Solid  waste streams  may require further  treatment  and/or
     landfill  disposal.   Aqueous waste  streams  may  be  dis-
     charged  to municipal  or industrial  sewers or  may require
     treatment,  depending  upon  the  nature of  their  constit-
     uents.   Following  the  removal  of  particulates   and  acid
     gases  by  air  pollution control  equipment,  off-gases  are
     discharged  through a  stack.

7.    Process  Effectiveness
     Mobile rotary  kiln  incineration has  achieved destruction
     efficiencies as high  as  99.9999  percent.

8.    Feedstock  Preparation Requirements
     Since  feedstock must  be 1/4-ln. or  less in  size,  debris
     and  drums  containing  the  wastes  must  be  crushed  or
     shredded  prior  to   feeding  to  the  kiln.    To  provide
     continuous operation  while minimizing the  possibility of
     residuals   of  contaminants  remaining  in  the   larger-sized
     particles,   feedstock   requirements   generally   specify
     material 2 in.  and less  in Diameter.

9.    Staff  Training Requirements
     Mobile  rotary  kilns  require   substantial  operation  and
     maintenance expertise,  including significant  'knowledge of
     automatic  controls  and instrumentation.   Hence,  operators
     responsible for  the  system require  specific  training for
     these systems.

10.  Manpower Requirements
     Personnel  required for  the adequate operation and mainte-
     nance of  mobile rotary kiln incinerators include 1  super-
     visor, 2 operators,  and 4 yard-crew workers.
-67-
                                                      11.  Process Limitations/Constraints
                                                           Constraints  pertaining to the  use of rotary kilns  include
                                                           the  following:
                                                                 a)   Susceptibility  to  thermal  shock.
                                                                 b)   The  need  for  additional  air  to make  up  for
                                                                     leakage through the kiln's end seals.
                                                                 c)   High particulate loadings.
                                                                 d)   Relatively low  thermal  efficiency.
                                                                 e)   High capital cost.
                                                           Wastes  containing high  levels of inorganic salts  degrade
                                                           the  refractory lining  and cause slagging of the  ash.   High
                                                           concentrations  of heavy  metals can result  in  emissions of
                                                           heavy metals which  are difficult  for air  pollution control
                                                           equipment to remove.

                                                       12.  Equipment Mobility
                                                           Full-scale  rotary kiln incineration systems are generally
                                                           mounted  on  multiple   flat-bed  trailers.  For  example,  the
                                                           EPA-ORD  Mobile  System  consists  of  three  trailers:  the
                                                           first  trailer  carries  a  shredder, a  hydraulic-ram feed
                                                           system,   and the  rotary  kiln;  the  second  trailer  carries
                                                           the   afterburner  and   a  water  quenching  system;  and  the
                                                           third trailer contains a particulate  scrubber,  a  process
                                                           stack,  and  a generator.  These components and the trailers
                                                           themselves   are  designed  so that  they can  be  intercon-
                                                           nected.   These trailers  meet  Federal and  state weight and
                                                           size requirements for  Interstate highways.

                                                       13.  Site Preparation  Requirements
                                                           Site preparation  requirements  for  implementing  a  mobile
                                                           rotary  kiln incineration system are as follows:
                                                                 a)  Properly  graded access road.
                                                                 b)  Concrete  pad for  rotary kiln.
                                                                 c)  Spill control/containment measurers.
                                                                                    -6B-
-------
      M.   Time Requirements/Constraints
           Rotary  kiln   incineration,   being  a  multiple-component
           system,  requires  several  weeks to  set  up the  equipment
           on-site.   Demobilization  may   require  more  time   than
           mobilization,  depending  on   the  complexity  of  equipment
           decontamination.
                                                                                          Typical  treatment  costs  for contaminated  soil  are  esti-
                                                                                          mated at $150  to  $500 per ton.   This  cost  depends upon the
                                                                                          waste matrix, contaminants,  and  heat value.
no
.Cr
00
15.   Health and Safety Requirements
     Since the system produces solid, liquid, and gaseous waste
     streams,  extreme  care should be  taken  in  handling these
     process residuals/effluents  for disposal.   Operating  per-
     sonnel should use  protective  equipment,   assuming these
     wastes to be hazardous wastes until  proven otherwise.

16.   Utility Requirements
     Utilities required for on-site  mobile rotary kiln  incin-
     eration include:
          a) Process water
          b) Electrical power
          c) Auxiliary fuel
       17.   Permitting Requirements
            Both  state and Federal permits are  required to  install  and
            operate rotary kiln incinerators.  Discharge of wastewater
            to municipal or industrial sewers requires compliance with
            regulatory requirements.   Emissions from the process  (off-
            gases discharged through  the stack) require air  pollution
            control permits.   Oxygen  (Oj)   and  carbon  monoxide  (CO)
            concentrations are continuously monitored within  the  stack
            to assure compliance with regulatory requirements.
       18.   Estimated Costs
            Costs depend  upon the  system's  design and size.   Capital
            costs for mobile rotary kilns can vary greatly.   Operating
            costs depend on the types of wastes  and the site location.
                                     -69-
                                                                                                                           -70-
-------
                          SECTION 7

                FEEDSTOCK  PREPARATION PRACTICES

    The  performance  of several  feedstock  preparation  systems
was  observed during  actual  remediations  at  hazardous  waste
sites.   Only  in  the  field  operation  of   feedstock  handling
equipment can the full  range of  on-site conditions be found. No
hypothetical evaluations  can provide tha diversity of materials
encountered in the hazardous waste feed material itself.   As an
example, a  bolt that  passes the screen separator only 1/100 of
the  time might  cause costly system  failure that would  not be
discovered  in dry  runs.   It is  imperative to define these real-
world  upsets  before  the  next wave  of  Superfund site cleanups
begins.

    The  feed preparation  systems observed  included  both  off-
the-shelf and custom-modified equipment.   Custom modifications
were  used   principally  where spatial  relationships prohibited
the  use of  off-the-shelf   products.  In  general,  these  custom
modifications differed little  in design  from the off-the-shelf
equipment.  One significant area  of design difference was in the
provision of  dust-control shielding.   The comparison of  covered
custom and  off-the-shelf  uncovered conveyors  illustrated  the
significant  increase in  performance  that  minor modifications
can provide.

    The  field   examinations  described   below   suggested   that
modifications  to  existing  equipment,   or different  equipment,
must  be  obtained in order to:
     •    Effectively handle platy-type materials on screens.

     •    Provide  easily  removable dust-containment  covers  to
         facilitate equipment repairs.
                              -71-
    •    Minimize potential of screen passage of spear debris.

    •    Provide  methods  better  than   the  hand-cleaning  of
         screens.

    •    Provide better  control  of  fugitive dust  emissions at
         material-transfer points.

    In  addition  to  the  modification  of  hardware,   the  field
examination found that significant increases in efficiency were
achieved  by  minor  differences  in  operational  practices.   The
documentation  and  compilation  of   such  operational  practices
could  provide extremely  valuable information  for  the environ-
mental remediation industry.

    The mobile  treatment  technologies discussed  in the  follow-
ing  subsections  were selected  as  representative of national
problems faced in the cleanup of hazardous waste  sites.

INFARED INCINERATOR
    The  Peak  Oil  Site,   located   in  Brandon,  Florida,   was
examined  in order  to observe  feedstock preparation practices.
The  Peak  Oil  Site is  the  test  facility  for  an electrically
powered  infrared   incinerator   operated  under  the  Superfund
Innovative Technology Evaluation  (SITE) program. The historical
use  of  the Peak Oil  Site was  as  an oil reprocessing facility.
The principal  materials  found on the  site  and addressed in  the
SITE  demonstration were   from  waste  lagoons.   The   lagoons
contained  water,  process  sludge,  and sediment.  Contaminating
materials were PCBs,  furans. and dioxin. Processing of  the site
materials began with  the initial removal of  the supernatant  in
the  lagoons.   The  resulting sediment was thickened through  the
addition of  sand,  soil,  and dry lime.  The  added materials  were
mixed  into the  lagoonal materials   by drag-lines, buckets,  and
                              -72-
-------
backhoes.   A  consistency  was   obtained   that   made  possible
handling through conventional front-end loaders and backhoes.

    This equipment excavated  the thickened material  and  trans-
ported  it  to a  primary  power  screen.  The screen  was  equipped
with a coarse screen at the influent feed-equalization  chamber.
Material passing  this  screen was deposited on a  belt  conveyor
and  was transported  to  the   elevated  secondary  screen.  The
secondary  screen  was fabricated  with  a  1-in.   mesh  and  was
operated in a vibratory mode.

    The intended purpose of the  power  screen was  to "break  up
lumps,  blend,  and  aerate  the  feed." The  attempt to  break  up
lumps  was  partially  accomplished.   However,   a  small  but
significant  fraction  of  the aggregated lumps  appeared to roll
down the screen without disaggregation.   These lumps did easily
disaggregate upon  impact  with  an effluent shield after passing
off  the  screen.   Increasing  the  residence  time  on  the  screen
may  have  solved  this  problem.   The  desired  achievement  of
blending of  the  feed  in  this equipment  is doubtful. Aggregated
particles  were  bypassed  from  the feed, separating the material
that  had higher  cohesiveness  from the  feed  stream".  Addition-
ally,  since  this process operated  on  only a small  fraction of
the  total  waste  at a  time,  the .scale of blending was  small. It
was  observed that the majority of  the  blending of  the  feed took
place  not  in the power screening,  but  in the excavation phase
immediately  prior to  the power  screening. The stated  objective
of  the power screening was to aerate  the' feed  material. This
was  accomplished through  free-fall of the  feed material to  a
storage  pile below the  l-in.  vibratory screen.    Ho guards or
containment  shields were  employed  to control  potential fugitive
dust or vapor emissions during this unit's operation.
                              -73-
    Debris  observed  on-site  included  large  concrete pavement,
demolition-type  debris,  rags,   roots,   pipes,   several  small
tanks, and  paper/plastic  trash.  This material was  addressed  in
several  unit  operations.  The  largest  debris was  deliberately
not excavated.  The smaller debris  was  excavated and passed  to
the power  screening unit.  The initial  coarse  screen extracted
materials grossly  unsuitable  for  the conveyor.  The final l-in.
vibratory  screen  separated the  feed material   and  the  smaller
debris.  The smaller  debris present at  the  time of  observation
was  principally   stringy  flat  plates  of  paper   or   plastic
sheeting. This  particular material  covered  much of  the  screen
surface  and contributed  to  bypass of undersized material to the
oversized bin.  A  screen  attachment  had a very  high angle  from
the horizontal. This configuration appeared to  be  an attempt to
transport  this  screen-blinding  material  off  the  screen  as
quickly  as  possible.  The net  effect,  however,  was to  decrease
residence time  for legitimate  soil aggregates  and  to  decrease
the effective sieve size  of the screen.

    The  material  passing the  screen  was excavated  by  backhoe
and  placed  in  a  feed-equalization chamber  for   incineration.
This  feed-equalization  chamber fed an  inclined-screw  conveyor.
The conveyor  system  appeared  to  operate  without upset  for  this
feed.  The  inclined-screw conveyor  was  covered  with  a  temporary
cylindrical  cover  that  could  be  removed,   if required,   for
maintenance  or  repair.  Dust  suppression  was  accomplished  by
this  cover.    Control  of  fugitive vapor   emissions   was   not
addressed  in feedstock  handling. The  power  screen  was  specif-
ically used to increase  the  contact of  contaminated soil  with
uncontrolled air flows.
                                                                                                                   -74-
-------
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ui
    The last  operation in the feedstock  handling scheme was the
use of rotary screws  to  spread the  feed material evenly,  with
uniform  thickness,  on  the  wire-mesh  belt  that  carried  the
material through  the primary extraction  and  combustion chamber.
This  application  of  screw  conveyors   mixed  the  feed  while
conveying it.

    Solid effluent  from the incinerator  wire-mesh belt  was fed
to  a  screw conveyor  for  discharge.  Quenching of the hot solids
occurred, and the warm  material was  allowed to drop  from the
screw  conveyor  to   a  windscreen-protected  waste  pile.  Extrac-
tion  of  the  waste  pile was  accomplished through  the use  of  a
Bobcat-type front-end loader.

    The  processes  involved in  feedstock handling are outlined
in  the process  flow  diagram (Figure 8).

ROTARY KILN INCINERATOR  AT BEARDSTOWN, ILLINOIS

    The  Lauder  Salvage  Vard  in   Beardstown,   Illinois,  was
observed to  examine feedstock preparation techniques.  A mobile
rotary  kiln  incinerator  was  observed   in  operation  at   this
site.   The   Lauder   Salvage Yard  was   formerly  an automobile
junkyard that had,  on occasion, drained  transformers to recover
recyclable  materials.   The  drained  oil  contained  PCBs   and
contaminated  the  surrounding  ground.    Contaminated  material
that  was  segregated at  the site included assorted metal debris
ranging  from automobiles  to small  pieces  of  sheet  metal.  The
contaminated  soil  that  was treated in the  destruction  tech-
nology  demonstration was a  sandy   loam with' some  naturally
occurring  cemented  aggregates. Debris   addressed  in processing
the feed  material included  roots  and pieces  of wood,  wire,  and
hose,  as  well  as various-sized fragments of ceramic insulation.
The site materials addressed  were  all   above  the  local   water
table.
                              -75-
                                                                                                                         Site Materials
                                                                                                                       Dewatering Through
                                                                                                                        Gravity Drainage
                                                                                                                          of Lagoons
                                                                                                             Lime
                                                                                                           Sand/Soil
                                                                                                                             J.
 SkJdge
Thickening
                                                                                                                          Excavation
                                                                                                                            Power
                                                                                                                          Screening
                                                                                                                            Feed
                                                                                                                          Equalization
                                                                                                                            Feed
                                                                                                                         Equalization
                                                                                                                         » Treatment
                                                                                                                           Process
                                                                                            IZ-Z87.
                                                                                                            Flour* 8. Peak Oil «M«
-------
ro
VJ1
IV)
    Highly contaminated  soil  had been  excavated,  stockpiled.
and covered with plastic pending  permit  approval  for  incinera-
tion.  Soil having  lower  levels of  contamination (lv«o« Yard rotary kiln man
                                                                                                                                    i flow diagram.
-------
       Material  passing the initial screen was  directed to an open
   flat-belt  conveyor. This  conveyor  transported the  material to
   the final  screen, which had a l-l/4-in. mesh. The  conveyor and
   vibratory  screen were constructed  as  one  unit,  manufactured by
   Royer.  The belt  on  the conveyor was  subject  to shredding due to
   the passage  of  splinters  or  spear-shaped  debris  through the
   primary screen.  No satisfactory solution  to this  problem was
   found at  this  site.  Down-time was minimized  from  this type of
   upset  by   keeping   a   supply  of   replacement  belts  on-site.
   Fugitive  dust  and  vapor emissions  were addressed  through the
   use of passive water sprinklers. The  conveyors were open to the
   atmosphere  and  weather,   and a  rain  of  sand  particles  was
   observed under the operating equipment. This  rain  was attribu-
^ ted to  particle  release from the  return belt, rather than  from
l~° material  loss,  as  the material  was  transported.  The conveyor
   discharged onto  the  secondary  screen as  the belt  passed the
   high-end  pulley. This material transfer  did generate  dust at
   this point. Ho containment or suppression was noted  at the  time
   of observation.

       The secondary  screen  was inclined  to  the horizontal to
   allow  passage  of  the  oversized  material from  the  screen. The
   screen  surface  was covered  with  a  rubberized-fabric mat. The
   feed  to  the screen  passed  between  this  mat  and  the  screen
   surface. This mat was fabricated to provide  increased residence
   time  for  the feed material  as well  as to  supply dust  control
   through the  actual screening.  This  shield  performed  well in
   actual  use.  accomplishing  the desired tasks. Minimal bypass of
   undersized materials was observed,  and the  screening itself was
   a  relatively  low-dust operation. Oversized  material  was  allowed
   to  drop into  a  six-cubic-yard container for  future  processing.
   Undersized material  was allowed  to  drop  onto  a conveyor  that
   discharged to a screened feed pile.
                                 -79-
    The screened  feed  was excavated  by a front-end  loader and
was transported  a short distance  to  a scale,  then immediately
to  a   feed-equalization  chamber  at   the   incinerator.  Feed
material placed  in  this  chamber was withdrawn  through  a flight
conveyor  and was transported  to  the feed-equalization chamber
for the screw conveyors that transported  the  feed to the rotary
kiln. The  size.limit for the  rotary  kiln system was determined
by  the  screw  conveyor  size  (less than  3-in.).  The screening
process  and  the  feedstock preparation  attempted  to  provide
material  with a  maximum  diameter  of  l-in.   as  a  precaution
against upset.

    The flight conveyor was enclosed in a metal  sleeve; access
was provided through a  removable  upper  plate.  The complexities
involved  the repair and  maintenance  of this enclosed equipment
became obvious when a  chain link  separated  in the flight-chain
belt.   Poor  access  provided by the covering sheath  resulted  in
excessive  repair  time.  In  addition,   the  risk  of  personnel
contamination  and  injury  was  enhanced by the restricted  work
space provided by  the cover,  even  when it was fully  opened.
Process upsets of this type during operation of the  incinerator
would  require   removal  of   the   contaminated  feed  from  the
conveyor  by hand prior  to  obtaining  access  for repair of  the
equipment.

LOW-TEMPERATURE THERMAL STRIPPIHG

    The  extraction of   volatile  organics  in  soils   through
thermal  methods  has  been  demonstrated  in  an on-site  mobile
treatment  unit developed and  operated  by Roy  F. Weston,  Inc.
(WESTON).    This  equipment,   called   the LT3   (Low-Temperature
Thermal Treatment System),  was observed  in operation at a site
in  Springfield,  Illinois.  Feed  preparation   and handling  was
examined at  this  site.
                                                                                                                      -80-
-------
        This  site  was  formerly a garage  owned  and operated by the
    State of  Illinois.   Leaking  underground storage tanks contami-
    nated  the  soil  under  a  large concrete  apron surrounding the
    buildings.  Contamination in  the  soil  was principally petroleum
    hydrocarbons  associated with leakage  from motor  fuel tanks.
    The  soil  had a  high clay  content and  exhibited a  well-devel-
    oped,  blocky  structure  in  freshly  excavated  surfaces.  The
    moisture  content  of the  soil  was  critical  in modifying the
    handling/processing  character of  the excavated material.  When
    the  soil  was   excavated,   it  was  plastic.  Upon  drying,   as
    frequently  occurs  in  storage piles,  the  soil became hard  and
    extremely difficult  to  disaggregate.

ui       Excavation   of  the  contaminated  material  began  with  the
    removal  of  the concrete apron.  This material was not segregated
    during excavation  and was  included in the feed material storage
    pile.  Other  debris encountered  in the   feed  storage  piles
     included lengths of  tank piping  and  electrical conduit,  as well
     a broken fragments  of drainage  tile.  Excavation by  a backhoe
     proceeded to a depth of approximately 8 feet,  which intersected
     the local water table. The excavation produced  a series of feed
     storage  piles which were  covered with heavy  plastic  covers  to
     minimize fugitive vapor  and dust emissions.  Covering  the feed
     storage  pile was very  important  in the controlling  the loss of
     soil moisture.

         Materials  from  these  storage piles  were  moved to the  LT
     feed preparation  trailer  through the  use   of  a small  backhoe/
     front-end  loader  combination.  The feedstock pile was  excavated
     and  loaded onto  the  vibratory  screen.  The  bucket  from  the
     front-end  loader  containing  the  unprocessed feedstock  was slow-
     ly discharged onto a vibratory screen.  As  the  vibratory  screen
     was  loaded, a  fine water-mist was  sprayed onto the screen to
     control  the dust generated in the material  transfer  operation.
                                   -81-
    The vibratory  screen was  installed  in a  horizontal posi-
tion. This  screen  had a 1-1/4-in mesh.  Operation of the screen
showed good residence time and  sufficient disaggregation of  the
soil agglomerates.  Soil material in  the oversized stream could
not be further broken without  the use of  hammers.  Little or  no
bypass  of  undersized  materials was observed.  Similarly,   no
cstectable dust was  observed in the operation  of the vibratory
screen.

    The  intended  purpose of the screen was  to  separate over-
sized material that could r.ot  be  processed through  the screw
conveyors.   These  screw  conveyors  were   located  immediately
below  the  screen   and  were fed . by  the   undersized  material
sliding  along the  sides  of   steep-walled bins to  the screw
conveyor entrance. The  screw conveyors were used to gather  the
undersized materials  and to convey them to the  enclosed flight
conveyor.  The process  of feedstock preparation utilized in  the
LT  is diagrammed in Figure  10.

    All  equipment  was   observed  in  operation  while processing
material.   One  significant  process  upset  occurred   in   the
vibratory  screen during the  observation  period.  This  process
upset  has  been   reported   to  occur   periodically  in  other
vibratory  screen operations.   A  splinter-shaped  piece  dropped
from the screen and was  passed  into the  screw conveyor. Once in
the  screw conveyor,  this  piece  lodged,  requiring  total  feed
system   shutdown   and   manual   extraction  of   the  upsetting
material. Feed material being processed during the upset had to
be  manually extracted  in order  to  gain  access  for  equipment
repair.
                                                                                                                       -82-
-------
             Matttial Excavation
                   1     ""
             Material Stockpiling
             Stockpile Excavation
               and Transport
              Primary Vibratory
                 Scmn
 ConooionBln
 Screw Convtyor
   ColMlon
                            Ovcnrttwl Material
                               CoMdlon
    Flight
   Conveyor
 Trough
Discharge
 Disposal
    The  screw-conveyor-accumulated  feed  material  was  gravity
transferred  to  a  flight  conveyor.  Initial  bypass  occurred,
which was  attributable to the fineness  and lack of cohesiveness
of  the  feed material.  This  was  corrected  by decreasing  the
residence  time on  the  flights  as  the conveyor  speed  was  in-
creased. The increased speed  delivered the  material adequately
to  the  feed-equalization  chamber/vapor-suppression  trap.  The
flight  conveyor  utilized a quick-release  cover. This cover  was
used  for suppression  of fugitive  emissions.  The quick-release
feature  provided  ease  of  maintenance and  repair.   The  feed-
equalization  chamber,   once  filled,   was   constantly   being
replenished  during the operation  of the equipment and  provided
surge  protection  for  the  feed  train  of  the treatment  unit
itself.  In  addition,  it provided  a barrier  to effluent  gasses
from the heated  auger.

    The feedstock  preparation  mobile on-site treatment  unit
performed  as  designed  and  contributed  to  a smooth  operation.
Equipment  used on-site included:

    Feed delivery system -  Custom-designed  Thomas & Mullet Co..
Inc.,  equipment  included  an enclosed . feed-screw assembly  for
undersized material collection  from  the  vibratory  screen and a
custom-designed  flight  conveyor  to  elevate  material  to  the
LT  feed-equalization  chamber.    The vibratory screen  used was
a  modified,  double-deck, 4-in.-by-10-in.  Simplicity Screen Kit,
Model  K2410-86-1760.   This  was  operated  with  a  single  screen
deck.

SOIL HASHING
                                                                             Soil washing  is the  use of mechanical  and/or chemical  means
                                                                         to  disperse contaminated soil into a wash fluid  and  to separate
Figure 10. LT3 reednaefc preparation pieeiee flowdigram.
                                                                                                       -84-
                   -83-
-------
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the contaminant  from the  soil.  Contaminants  that  are water-
soluble  are  easily  washed  away   from   the  soil   particles.
Insoluble contaminants require more rigorous methods, the  first
step being the separation  of  the soil into appropriate  particle
size  fractions.   Insoluble  contaminants   adsorb  to  particle
surfaces. Since  fine particles  have  a  high surface  area  for  a
given weight,  contamination  is  higher  for  the finer  fractions
than it  is  for the  coarse fractions, each fraction  presenting
different  requirements   for  processing.  The  EPA Mobile   Soil
Washing  System  (MSWS)  was  designed around this particle size
separation scheme.

    The  Mobile Soil  Mashing  System  consists   of  two pieces  of
trailer-mounted  hardware.  The  first  is  the  drum screen unit
(DSU)  schematically  shown in the upper  portion  of   Figure  11.
The  second  unit is  a froth  flotation  unit (FFU) shown  in the
lower  half  of Figure 11.  Both  of these  units require support
equipment to  operate. Earth-moving equipment  is  needed to bring
the soil to the drum screen, and a treatment  system  is required
to allow recycling of the  spent wash  fluid.

    Contaminated  soil  is fed  into   the  system  through  a soil
feed meter  on the drum screen.  In order  for  the  meter to work.
cobbles  larger than  1  in. in  diameter must  be  screened out  of
the  soil.  The soil  meter is then able to deliver  soil  to the
first  screen  at  a controlled  rate.

    The  drum screen  separates  the soil into two particle  sizes
— greater  than  2 mm. and less  than  2 mm.  The particles greater
than  2 on.  are tumbled  and  washed in the the  drum section. This
process  starts  inside  the first cylindrical  screen.  While  the
screen  rotates,  the soil  is  tumbled and broken-up  by  high-
pressure streams of water.  Soil that  is fine  enough to pass
through   the  screen   becomes part of a slurry that  is  pumped to
                                   -S5-
                                                                                       10
                                                                                       c
                                                                                     1/1
                                                                                     o
                                                                                       n
                                                                                       •3
                                                                                       a
                                                                                       rn
                                                                                       •O
                                                                                        O
                                                                                        er
-------
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the froth  flotation  unit.  The  larger  particles  (greater than 2
mm.) are picked up and deposited  in the rotating drum.

    The drum,  as well as  both screens, are  on  an incline.  It is
this incline,  in combination with the rotation, that causes the
gravel to move along the screens. Approximately fifteen minutes
is  required to  wash  the  gravel while  it  travels from the first
screen to the  second.  During this washing, additional material
that is less than 2 mm. is  removed from the gravel.

    The  second  screen allows  for final  separation  of  the two
particle  sizes.  A  diluted  slurry  of   fine  particles  passes
through  the  screen  and  is  pumped to  the  nozzles  of the first
screen.  Meanwhile,   the  gravel   is  given  a  final  rinse  with
sprays  of  clean wash fluid before  discharge into bins or di-
rectly back to the ground.

    The  particles  that are less  than 2  mm.  are washed in the
froth  flotation unit  while  the  gravel   is being  washed in the
drum screen. The slurry created in the sump of the first screen
is  pumped  from the  drum screen  to  the  first cell of the froth
flotation  unit.  In this cell,  as in each of  the other three
200-gallon  cells,  the slurry is agitated  and sparged.  If  a
froth  is formed by this  action,  it  is skimmed from the surface
by  a  rotating paddle wheel.  The  non-frothed  slurry is pumped to
a hydrocyclone.

    The  function of a  hydrocyclone is to remove solid particles
from  a liquid slurry. A hydrocyclone's effectiveness depends on
the density,  size, and shape of  the particles.  In  general,  soil
particles  with a  density  of 2.6 gm./cm.3 and less than  0.075
mm.   in  diameter  will  not  be  removed from the slurry. These
                                 -87-
particles, with  the  liquid,  will pass  out of  the top  of the
hydrocyclone. This material  is  called the overflow. The solids
that are  concentrated by the hydrocyclone pass out the bottom
(the apex) along  with the liquid. This  material  is called the
underflow.  In order  to  keep  working  properly,  the  underflow
cannot  have  more  than  10  percent  suspended  solids.  This
characteristic .of the hydrocyclone  is a  controlling  factor  in
the whole system's processing rate.

    The overflow  and  the underflow of the  hydrocyclone flow  in
opposite  directions.  In  Figure 11,  the  concentrated underflow
of each subsequent hydrocyclone is deposited  in the cell to the
right of  the hydrocyclone's  feed source.  The overflow  is depos-
ited to the  left  of the hydrocyclone's feed  source.  This  coun-
tercurrent process  results  in two outputs from the froth flota-
tion unit. They  are:   1) the majority of  the soil in a concen-
trated slurry that  is considered the clean soil;  2) the major-
ity of the spent  wash fluid  along with finer  fractions of the
soil.

ROTARY-DISK  FILTRATION

    One piece of  feedstock preparation equipment,  a rotary-disk
filter manufactured by AT AM, Inc. of  Poynette,  WI . ,  was tested
at  the OHMSETT  facility.  Effluent  from  the  EPA  Mobile  Soil
Washing System was  used  as  feed material.   Soil used in testing
was  a  "Freehold  series"  soil that  had  been judged by previous
investigators to be  typical of  EPA  Region  II  Super fund  site
soils.
    Rotary-disk  filters  were  selected  for this  test  because
 they  provide continuous filtration with  high-volume  throughput.
 Additional   benefits  claimed  for  rotary-disk  filters  include
 automated operation and  absolute particle  removal  on a  single
 pass.  Since  no cake  is  formed during  the process,  flow rates
 are   maintained.    However,   this  produces  a  slurry  effluent
 ("vessel  drains")  that  requires  further dewatering.
-------
          Performance of this processing  equipment with the  test  soil
      wag  limited  by the fine grain  size of the feed material,  which
      produced  colloids  that  would  not  settle  to  produce a  clear
      supernatant.   The results of  the test  are  shown in  Figure 12.
      Scheduling problems  precluded additional  test  runs at OHMSETT.
      but  further  testing with  other soils and with  colloid-breaking
      chemicals   is  recommended   in  order  to   provide   a   better
      definition of  the range of applicability of  the  ATAM unit.
Ul
CO
                                     -89-
                                                                                                                                              0.2S  OS    1.0
                                                                                                           Figure 12. ATAM equipment leil results.
-------
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                             SECTION B

            FEEDSTOCK PREPARATION EQUIPMENT DATA BASE

    The  equipment  selection process  for mobile  on-site  treat-
ment  technologies would be  greatly  facilitated by the  prepara-
tion  of  a thoroughly  cross-referenced data  base  of  equipment
evaluations  and observations.  Such  a  data  base  could   aid  a
remedial   engineer  in  the  selection  of  a  specific  piece of
feedstock  preparation   equipment.   This  equipment   information
data  base would include items such as the following:

    •    Equipment/process description.
    •    Vendor name, address, phone number, contact.
    •    Type of materials/debris handled.
    •    Mobility/transportability.
    •    Purchase/lease costs and terms.
    •    Set-up/dismantling costs and time.
    •    Labor requirements.
    •    Capacity.
    •    Efficiency.
    •    Operating/maintenance costs and requirements.
    •    Permitting  and safety requirements.
    •    Utility requirements.
    •    Site preparation requirements.

    The  data base management  system could include  the capabil-
 ity to search for  specific  ranges  in the. fields. -For example,
 selecting  equipment  that  could  operate  within a  given  cost
 range  and   capacity  would  be   useful,   particularly  where  a
 "unique"  Superfund  site  must  be   addressed.   Screens  for  the
 proposed  data base  could  be set  up  as shown  in the  following
 pages.
                                     -91-
                                                                                                                            PERFORNANCE/COST DATA BASE
                                                                                                                              DATA ENTRY 9CET
                                                                                                                                VENDOR DATA
                                                                                                 1.  TEDHLflSY_

                                                                                                 Z.  PROCESS
                                                                                                    VENDOR
                                                                                                    NAME
                                                                                                    PHONE	
                                                                                                    CONTACT
                                                                                                 «.  EOUIPKXT (P-PRINARVi A-AUIILtARY)
                                                                                                    CODE              ITEM
                                                                                                                                       COST
                                                                                                5.   LABOR
                                                                                                    OPER/miN
                                                                                                    SJWIS10N '
                                                                                                    ANALYTICAL
                                                                                                6.            TINE
                                                                                                    NGBIL1UTION
                                                                                                    DEMOBILIZATION
                                                                                                7.  UTILITIES

                                                                                                   UATER
                                                                                                   ELECT
                                                                                                   FUEL
TYPE
                                                                                                                     COST
      OUMTITY   COST
                                                                                                S.  FEED PREPARATION
                                                                                                   PROUSS	
                                                                                                   COSTS
                                                                                                    EOUIP.
                                                                                                    OM
                                                                                                9.  SITE PREPARATION
                                                                                                   ACCESS ROAD
                                                                                                   PAO/SRADINB
                                                                                                   SPILL/CONTAIN
                                                                                                   SECURITY

                                                                                                10.  SOURCE/REF.
      COST
-------
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OS
o
                                                         SCION I
                                                PERFtMMCE/COST DATA ERSE
                                            MTR ENTRY 9EH/PERFOWKE SUWARV
              TEWBL06Y CPIEBOHY:.

              PROCESS:	
              HASTE OflSSi
              PROCESS EFFICIENCY:
                   MRSTE REMMD/DESTROYED!
                   UASTE VOUK REDUCTION:

              RESIDUES:
                 FORK:	
                 TRERDCNT NEEDED:.
                 FEED PREPARATION:.
                               TY (FEED RATE)
                     LIQUID UASTE:
                  COST ESTINATEl   CAPITAL.

                  SOURCE/REF:
                                                    URSTE FORM:
                                                   VO1K:
_SatO UAETE.

   DM 	
                PROCESS STATUS   HASTE/RESIDUES CLASS I FORN  RESIDUE TREAT  FEED PREP
                C-OMCKIIL     0-ORGAJfICi I-INDRBRNIC       A-«IR          C-OUH
                P-P1LOT          S-SQLlDS/aUDeE/SDIL         D-OEWTER      S-SWED
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r\3
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                                                                                                                       -104-
-------
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-------
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                                                                                                                   -108-
-------
                             APPENDIX A
                        DEBRIS  IDENTIFICATION
   Cloth
     - Rags
     - Tarps
     - Matresses
                               Paper
                                 - Books
                                 - Magazines
                                 - Newspaper
                                 - Cardboard
                                 - Packing
CTv
OO
Glass
  - Bottles  (white,  brown,
    green, clear,  blue)
  - Windows
Plastic
  - Buckets
  - Pesticide containers
  - Six-pack retainer rings
  - Thin plastic sheets
  - Plastic bags
  - Battery cases
   Ferrous Metals
     - Cast iron
     - Tin cans
     - Slag
                               Rubber
                                 - Tires
                                 - Hoses
                                  -  Insulation
                                  -  Battery  cases
    Nonfatrous Metals
      - Stainless steel
      - Aluminum
      - Brass
      - Copper
      - Slag
                               Wood
                                  -  Stumps  and  leaves
                                  -  Furniture
                                  -  Pallets
                                  -  Plywood
                                  -  Railroad ties
                                 A-i
                                                                                                          DEBRIS  IDENTIFICATION
                                                                                                                (continued)
Metal Objects
  - Autos/vehicles
  - SS-gallon drums/containers
  - Refrigerators
  - Tanks/gas cylinders
  - Pipes
  - Nails
  - Nuts and bolts
  - Wire and cable
  - Railroad rails
  - Structural steel
                                                                                   Electronic/Electrical
                                                                                     - Televisions
                                                                                     - Transformers
                                                                                     - Capacitors
                                                                                     - Radios
                                                   Construction Debris
                                                          - Bricks
                                                          - Concrete blocks
                                                          - Asphalt
                                                          - Stones and rocks
                                                          - Reinforced-concrete pipe
                                                          - Wood
                                                          - Steel beams
                                                          - Asbestos insulation and roofing/siding shingles
                                                          - Fiberglass insulation
                                                          - Fiberglass tanks
                                                                                                                    A-2
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                           VENDOR LISTS

 The   following  manufacturer,  vendor,  equipment,  and  product
 lists were  prepared from vendor literature  obtained  during the
 course  of  the  project,  including the  Landfill  Equipment Guide
 published  in the  August 1988  edition of  Waste  Age magazine.
 This  Guide  is  updated  annually.   Additional   equipment  and
 material  sources  can be  found  in the  local telephone business
 Yellow  Pages  for   the  area  in which  a  site  is  located.    In
 addition,  the Thomas Register  has listings for  these vendors,
 and  others  that  may  have  identical  or  similar  equipment and
 products  that could achieve  the  same  results.    This  list was
 prepared  to  enable the  remedial  designer  to begin  an  initial
 vendor  and  product  search.
ON
  In  selecting  equipment   and  products  to  be  utilized,   the
  purchaser  should  review  with  each vendor  such  items  as  unit
  costs,  additional  equipment required for application, transpor-
  tation  charges, delivery  times,  equipment  maintenance  require-
  ments,  product  incompatibility,  required  operator  experience,
  safety  precautions,  and any other pertinent  or  special  require-
  ments .

  Excavation Equipment
  (See your  local phone book for  you*  area supplier)

  Backhoe Manufacturers

  FMC Corporation Construction Equipment  Group
  2800 Lakeside Drive
  Bannockburn, Illinois 60015
  312-295-5500
Caterpillar Industrial Products, Inc.
100 N.E. Adams Street
Peoria, Illinois 61629
309-675-5800

Deere & Company
John Deere Road
Holine, Illinois 61265
309-752-8000

Ford Motor Company
American Road
Dearborn. Michigan 48127
313-322-3000

Gradall Company
406 Mill Avenue. S.W.
New Philadelphia. Ohio 44663
216-339-2211

J.I. Case Company
900-T Alderson St..
P.O. Box 1087
700 State Street
Racine. Wisconsin 53404
414-636-6011

Ditch Witch
P.O. Box 66
Perry.  Oklahoma  73077-0066
                                B-l
                                                                                                                    B-2
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Bulldozers

Deere 6 Company
John Deere Road
Ho line, Illinois 61265
309-752-8000

Komatsu America Corporation
1900-T Powell Street
P.O. Box 8830
Emeryville. California
415-652-4567

Caterpillar Tractor Company
100 N.E. Adams Street
Peoria, Illinois 61629
309-675-1000
J.I. Case Company
900-T Alderson Street
P.O. Box 1087
700 State Street
Racine. Wisconsin 53403
414-636-6011

Front-End Loaders

Komatsu America Corporation
 1900-T  Powell Street
P.O.  Box  8830
Emeryville,  California
 415-652-4567
 Caterpillar Industrial Products,  Inc.
 100 N.E.  Adams Street
 Peoria. Illinois 61629
 309-675-5800
                               B-3
Deere & Company
John Deere Road
Holine, Illinois 61295
309-752-8000

Sperry New Holland
New Holland, Pennsylvania  17557
717-354-1458

J.I. Case Company
Drott Division
900-T Alderson Street
P.O. Box 1087
700 State Street
Racine, Wisconsin 53404
414-636-6011
Dredgemen Manufacturing Company
Suite  200
One Manyland Farms
Brentwood,  Tennessee  37027
615-377-1115

Wz & S Development Inc.
4957 Main Street
P.O. Drawer 297
Greenbush,  Michigan 48738-0297
517-724-5463
 Elliott Machine Corporation International
 1657  Bush Street
 Baltimore.  Maryland 21230
 301-837-7900
                               B-4
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 Mud-Cat Division
 5105-T west 35th Street
 P.O. Box 16247
 St. Louis Pack. Minnesota 55416
 612-893-6400

 Crisafulli Pump Co.. Inc.
 Box 1051 Crisafulli Drive
 Glendive,  Montana
 406-365-3393

 Can Densifiers

  John  Willis
^CP Manufacturing,  Inc.
MP.O.  Box 2516
  National City, California 92050
  619-477-3175

  Richard White
  Dens-A-Can International
  P.O.  Box  11505
  Pittsburgh,  Pennsylvania  15238
  412-231-4500

  Drew Morris
  Drew-It Corporation
   P.O. Box 10111
   Greenville,  South Carolina 29603
   803-294-0357
   John Fuchs
   Galland Kenning Nopak, Inc.
   1025 S. 40th Street
   Milwaukee. Wisconsin  53215
   414-645-6000
                                 B-5
Cranes

FMC Corporation
Construction Equipment Group
2800 Lakeside Drive
Bannockburn, Illinois 60015
312-295-5500

Caterpillar Industrial Products
100 N.E. Adams Street
Peoria, Illinois 61629
309-675-5800

Saf-T-Boom Corporation
1 Skyway Drive
Little Rock, Arkansas 72207
501-375-3291

Conveyors

Paul Griesedlieck
Hustler Conveyor Co.
Sub. of American Pulverizer  Co.
4985 Fyler Avenue
St. Louis. Missouri  63139
314-352-6000

John Loudis
International Baler  Corporation
5400 Rio Grande Avenue
Jacksonville, Florida 32205
904-358-3812  (In Florida)
800-874-8328  (elsewhere)
                               B-6
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 Edgar Ewe11
 Monarch Specialty Systems,
 713 W. Lafever Street
 Ossian. Indiana 46777
 219-622-7831
Inc.
  Chuck  Maguire
  Recycling  Equipment Mfg.
  N.  6512 Napa
  Spokane, Washington 99207
  509-487-6966

  Richard Veeck
reunited Farm Tools,  Inc.
^Miller Division
  P.O. Box 336
  Turlock, California 95381
  209-632-3846

  Judith  Stelian
  Beumont Birch Company
  3900 River Road
  Pennsauken, Hew Jersey 08110
  609-663-6440

  John Willis
  CP Manufacturing, Inc.
  P.O.  Box  2516
  National  City, California 92050
  619-477-3175
   Brian Trudel
   Carrier Vibrating Equipment  Inc.
   P.O. Box 37070
   Louisville, Kentucky 40233
   502-969-3171
                                 B-7
Joe Coniglio
Dover Conveyor
P.O. Box 300
Midvale, Ohio 44653
614-922-9390

Skip Foster
Dresser Industries/Jeffrey
Manufacturing Division
P.O. Box 387
Woodruff. South Carolina  29388
803-475-7523

Concrete Busters

NLB Corporation
29830 Beck Road
Wixom, Michigan 48096
313-624-5555

Concrete/Asphalt Planers

Kennametal, Inc.
Coal and Construction Tool  Division
Bedford, Pennsylvania 15522
814-623-2711

Ingersoil-Rand Company
Department B-417
254 East Washington Avenue
Washington, New Jersey  07882
717-532-9181

CMI Corporation
Oklahoma City. Oklahoma
800-548-9431
                                                                                                                      B-8
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 Wirtgen America, Inc.
 1717 Elm Hill Pike
 Nasville, Tennessee 37210
 615-367-1600

 Veca Long
 Flexowall Corporation
 2336 Merced St.
 San Leandro, California 94577
 415-357-2075 (in California)
 800-368-3421 (elsewhere)
  John Fuchs
  Galland Henning Nopak.  Inc.
-01025 S.  40th  Street
oj
  Milwaukee.  Wisconsin  53215
  414-645-6000
  Bill Guptail
  General  Kinematics  Corporation
  777 Lake Zurich Road
  Barrington,  Illinois 60010
  312-381-2240

  M.  Eilenfeld
  Grasan Equipment Co.,  Inc.
  P.O. Box 714
  Mansfield, Ohio 44901
  419-526-4440
  Paul Gruendler
  Gruendler Crusher Division
  General Steel of Indiana
  12955 Maurer Industrial Drive
  St. Louis, Missouri 63127
                                B-9
Myron Galanty
Franklin Miller, Inc.
60 Oakner Parkway
West Orange, New Jersey 07039
201-736-3900

C.H. Pendelton
G.E.w. Co.
P.O. Box 375
Branford, Connecticut 06405
203-488-2581

M. Eilenfeld
Grasan Equipment Co., Inc.
P.O. Box 714
Mansfield, Ohio 44901
419-526-4440

David Hawker
Hazemag U.S.A., Inc.
P.O. Box 1064
Uniontown, Pennsylvania 15401
412-439-3512

Hal Feldman
Jersey Stainless,  Inc.
230 Sherman Avenue
Berkeley Heights,  Hew Jersey 07922
201-464-1752
Fred Bunke
Prodeva,  Inc.
100 Jerry Drive,  Drawer  R
Jackson Center, Ohio  45334
513-596-6713
                                                                                                                     B-ll
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  Chuck' Haguire
  Recycling Equipment Manufacturing
  N.  6512 Napa
  Spokane, Washington 99207
  509-487-6966

  Norman C. St. Clair
  Riverside Products Division
  Sivyer Corporation
  P.O. Box 765
  Bettendorf. Iowa 52722

  Carl Oray
^Pennsylvania Crusher Corporation
-^P.O. Box 100
  Broomall, Pennsylvania 19008
  215-544-7200

  Richard Veeck
  United Farm Tools, Inc.
  Miller Division
  P.O. Box 336
  Turlock, California 95381
  209-632-3846

  Grinders for Wood Recycling

  Jerry Biedler
  Farmhand,  Inc.
  P.O. Box 1500
  23610 Highway 7
  Excelsior, Minnesota 55331
  612-474-1941
                                B-12
Powell Clinton
Fuel Harvesters Equipment, Inc.
12759 Loma Rica Drive
Grass Valley, California 95945
916-272-7664

Don Reis
Jones Manufacturing Co.
Route 1, Box 80
Beemer, Nebraska 68716
402-528-3861

Larry Burkholder
Morbark Industries
Box 1000
Minn. Michigan 48896
517-866-2381

Magnetic Separators

D.G. Morgan
Applied Magnetics
P.O. Box 20911
Milwaukee, Wisconsin
414-321-9739

Joseph B. Taylor
Carpco, Inc.
4120 Haines Street
Jacksonville, Floria 32206
904-353-3681
                                                                                                                     B-13
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  Ralph Tobect
  Dings Magnetic Co.
  4740 W.  Electric Avenue
  Milwaukee.  Wisconsin 53219
  414-672-7830

  Ed Tvichell
  Erie Manufacturing Co.
  P.O. Box 10608
  Erie, Pennsylvania 16514
  814-833-9881

  Alan Zelunka
r\jGensco Equipment Co.. Limited
Cn53 Carlaw Avenue
  Toronto, Ontario M4M 2R6, Canada
  416-465-7521

  Frank Harling
  Lindemann Recycling Equipment, Inc.
  500 Fifth Avenue, Suite 1234
  New York, New York 10110
  212-382-0630

  Richard Veeck
  Miller Manufacturing, Co.
  P.O. Box 336
  Turlock, California 95381
  209-632-3846
  Scott Newell
  Newell Manufacturing, Co.
  P.O. Box 9367
  San Antonio, Texas  78204
  512-227-9090
                                B-14
Chuck Maguire
Recycling Equipment Manufacturing
N. 6512 Napa
Spokane, Washington 99207
509-487-6966

Dan Omelina
Stearns Magnetics, Inc.
6001 S. General Avenue
Cudahy, Wisconsion 53119
414-769-8000

James A. Butke
O.S. Walker Co.,  Inc.
Rockdale Street
Worcester, Massachusetts  01606
617-853-3232

Plastics Recycling Equipment

Edmund Meier
Buss-Condux,  Inc.
2411 United Lane
Elk Grove Village, Illinois 60007
312-595-7474

Thomas R. Tomaszek
Nelmor Co.
Rivulet St.
N. Oxbridge,  Massachussetts C1538
617-278-5584
                                                                                                                    B-15
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    Louis J. Nobprini
    Ramco Products of Mossberg Industries
    160 Bear Hill Road
    Cumberland, Rhode Island 02864
    401-333-3000  (in Rhode Island)
    800-556-7834  (elsewhere)

    David Miller
    Rapid Granulator. Inc.
    P.O. Box 5887
    Rockford,  Illinois 61125
    815-399-4605

f^  Shredders

    Don Graveman
    American Pulverizer  Co.
    5540 W. Park  Avenue
    St. Louis,  Missouri  63110
    314-781-6100

    Diane Eckert
    Branick Industries
    P.O. Box  1937
    Fargo,  North  Dakota  58107
    701-235-4446

    Robert  Skodzensky
    Carthage  Machine Co.
    571 W.  End Avenue
    Carthage,  Hew York  13619
    315-493-3280
B-16
                                                     V.J.  Johnson
                                                     Centre Morgardshammar (Canada), Inc.
                                                     220 Humberline Drive. Unit 1
                                                     Rexdale. Ontario M9H 5Y4, Canada
                                                     416-675-2662

                                                     Bruce Bataglia
                                                     Columbus McKinnon Corporation
                                                     Shredder Division
                                                     Audubon & Sylvan Parkways
                                                     Amherst, New York 14228-1197
                                                     716-689-5400

                                                     Skip Foster
                                                     Dresser Industries/Jeffrey Manufacturing Division
                                                     P.O.  Box 387
                                                     Woodruff, South Carolina 29388
                                                     803-476-7523

                                                     Paul Gruendler
                                                     Gruendler Crusher Division
                                                     General Steel Industries
                                                     12955 Maurer Industrial Drive
                                                     St. Louis, Missouri  63127
                                                     314-849-3700

                                                     Ted Alderson
                                                     Hammermills, Inc.
                                                     Subsidiary of Pettibone Corporation
                                                     800 First Avenue, MW
                                                     Cedar Rapids, Iowa 52405
                                                     319-365-0441
                                                                                   B-17
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  Don Kaminski
  The Hell Co.
  3000 W. Montana Street
  Milwaukee. Wisconsin 53215
  414-647-3350

  Hal Feldman
  Hi-Torque Shredder Company
  230 Sherman Avenue
  Berkeley Heights, New Jersey 07922
  201-464-2002

  Keith Borglum
r\j Kay Industries, Inc.
13 Highway 218 South
  Janesville, Iowa 50647
  319-987-2313

  Kent Klawitter
  Komar Industries, Inc.
  4425 Marketing Place
  Groveport, Ohio 43125
  614-836-2366

  Ray LaBounty
  LaBounty Manufacturing, Inc.
  P.O. Box B
  Two Harbors, Minnesota  55616
  218-834-2123
  Frank Harling
  Lindemann Recycling Equipment,  Inc.
  500 Fifth Avenue. Suite  1234
  New York, New York 10110
  212-382-0630
                                B-18
Norm Kramer
MAC Corporation
201 E. Shady Grove Road
Grand Prairie, Texas 75050
214-790-7800

Andrew J. Pasztor
Maren Engineering Corporation
P.O. Box 278
S. Holland, Illinois 60473
312-333-6250

Robert Skodzensky
Mitts & Merrill, Carthage Machine Co.
571 West End Avenue
Carthage. New York 13619
315-493-2380

Alex Cobb
Montgomery Industries International
P.O. Box 3687
Jacksonville, Floria 32206
904-355-5671

Fuel Harvesters Equipment,  Inc.
12659 Loma Rica Drive
Grass Valley, California  95945
916-272-7664

Marrison-Knudsen Forest
Products Company,  Inc.
P.O. Box 7808
Boise, Idaho 83724
800-635-5000
                              B-19
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   Shred-Tech
   Cambridge. Ontario.
   519-621-3560
                    Canada
    Shred-Pax Corporation
    136 W. Commercial Avenue
    Hood Dale.  Illinois  60191-1304
    312-595-8780

    Oil/Water Separators
(V)
—q
Co
SCA Chemical Services,
60-T State Street
Boston, Massachusetts
                           Inc.
    National Fluid Separators,
    829-T Hanley
    St.  Louis,  Missouri
                           Inc.
    Roy Palmer Association, Inc.
    9S-T King Street
    Dover, New Jersey 07801
    201-625-0010

    York Separators
    42 Intervale Road
    P.O. Box 3100
    Parsippany, New Jersey

    McTighe Industries, Inc.
    1615 Ninth Avenue
    Suite 1-T
    Bohemia, New York  11716
    516-588-5800
                                  B-20
Envirotech Corporation
WEMCO Division
1796 Tribute Road
P.O. Box 15619
Sacramento, California

Casscorp
6777 Nancy Ridge Drive, Department T
San Diego, California 92121
619-450-2114

Niag-ra National Corporation
670-A Trabert Avenue. N.H.
Atlanta, Georgia 30318
404-355-8194

Sefilco. Limited
1234 Depot St.
Glenview, Illinois 60025
800-323-5431

Haniworthy USA,  Inc.
Pump 6 Compressor Division
10555 Lake Forest Boulevard
Suite 1F-T
New Orleans, Louisiana  70127

Bowden  Industries,  Inc.
7540 S. Memorial Parkway
Department H
Huntsvilie, Alabama  35802
205-882-9082
                                                                                                                     B-21
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   J.R. Schneider Co., Inc.
   5725 Paradise Drive
   Suite 400T
   Corte Madera, California

   Pollution Control Engineering, Inc.
   10751-T South Lakewood Boulevard
   Downey, California

   Separation & Recovery Systems, Inc.
   16901-T Armstrong Avenue
   Irvine, California

r\j SKIM, Inc.
—j
vo 1532-T South Samol Drive
   Los Angeles, California
   213-263-3829

   Garsite Products, Inc.
   10-T Grand Boulevard
   P.O. Box 4289
   Deer Park, New York 11729
   516-667-1010

   American Felt & Filter Co.
   P.O. Box 951-A
   Newburgh, Hew York

   Absolute Oil Separator Corporation
   57-15 32nd Avenue
   Woodside, New York 11377
   718-721-1138
                                 B-22
Abanaki Corporation
P.O. Drawer 149
Chagrin Falls, Ohio 44022
216-247-7400

Oil Skimmers, Inc.
12800-G York Road
Department WRT
Cleveland. Ohio 44133
216-237-4600

Fram Industrial Filtration and Separation
P.O. Box 33210
Tulsa, Oklahoma
Climton Centrifuge
P.O. Box 217
Department B
Hatboro, Pennsylvania
215-674-2424
19040
 Industrial Process  Systems,  Inc.
 109-T N. Wayne Ave.
 Wayne,  Pennsylvania

 Surface Separator Systems,  Inc.
 P.O. Box 5305
 Knoxville, Tennessee   37918
 615-688-8820
Broadbent,  Inc.
2684 Gravel Dr.
P.O. Box  185249
Fort Worth, Texas
817-595-2411
                                                                                                          76118
                                                                                                                    B-23
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cx>
o
Monarch Separators.  Inc.
6827-A Signat
Houston, Texas 77041
713-466-1974

Parker Systems. Inc.
2880-A Yadkin Rd.
Chesapeake, Virginia 23323
804-485-2955

Marco Seattle
2300 West Commodore Way
Seattle, Washington 98199
206-285-3200

Envirex, Inc.
P.O. Box 1067
Waukesha, Wisconsin 53187
414-547-0141

SEPARATORS

Gasoline

Velcom Filters,  Inc.
1750 Rogers Ave.
San Jose, California

Absolute Oil  Separator Corporation
57-15 32nd Ave.
Woodside. Hew York
718-721-1138
                                 B-24
Fuel From Hater

Douglas Engineering
A Division of U.S. Hydex, Inc.
4626-T Clayton Rd.
Concord, California  94521
415-827-9040

Foster-Miller, Inc.
6228 Geudta Dr.
San Jose. California

Arnetek,  Inc.
Process  Equipment  Division.
26531 Ymeg Rd.
Temecula, California

Layton  Industries,  Inc.
542-T E.  Squantam
North Qulncy,  Massachusetts

Foster-Miller,  Inc.
360  Second Ave.
Waltham, Massachusetts

Foster-Miller, Inc.
 57 Nassua Ave.
Manhasset,  New York

 Universal Filters, Inc.
 1601-T Fairview Dr.
 Building N.  3
 Carson City,  Nevada
                                                                                                                      B-25
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IV)
OO
Universal Filters. Inc.
1225-T Main St.
Asbury Park. New Jersey

Continental Separator Systems
P.O. Box 993-T
East Brunswick, New Jersey

The Kraissi. Company. Inc.
303 Williams Ave.
Hackensack, New Jersey

FLOTATION MACHINERY

Dorr-Oliver, Inc.
79 Havemeyer Lane
Stanford. Connecticut 06904
800-243-8160

AFL  Industries,  Inc.
3661-T w. Blue Heron Boulevard
Riviera  Beach, Florida   33404
305-844-5200

Clow Corporation
Waste Treatment  Division
P.O.  Box 68-T
Florence, Kentucky  41042
606-283-2121

American Density Materials,  Inc.
RD 2, Box 38E
 Belvedere,  New Jersey  07523
 201-475-2373
                                 B-26
Heil & Patterson. Inc.
P.O. Box 36
Department 10
Pittsburgh, Pennsylvania 15230
412-788-6900

FLOTATION UNITS

Skim, Inc.
1532-T South Sunoc Dr.
Los Angeles, California 90023
213-263-3829

Industrial Waste Systems/Davis Water
& Haste Industries,  Inc.
1828 Metcalf Ave.
Thomasville, Georgia  31792
912-226-5733

Komiine-Sanderson Engineering Corporation
100 Holland Ave.
Peapack, New Jersey  07977
201-234-1000

Monarch Separators,  Inc.
6827-A Signat
Houston, Texas 77041
713-466-1974

Follansbee Steel Corporation
Sheet Metal Specialty Division
One State St.
Follansbee. West Virginia 26037
                                                                                                                    B-27
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282
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no
cx>
                        ASSESSMENT OF CHEMICAL  AND  PHYSICAL  METHODS  FOR
                              DECONTAMINATING BUILDINGS  AND  DEBRIS
                                       AT SUPERFUND SITES
                                    Michael  L.  Taylor. Ph.D.
                                         Majld  A. Dosani
                                          John  A. Wentz
                                        Roxanne B.  Sukol
                                        Timothy L.  Kling
                                         Jack S. Greber
                                      PEI Associates. Inc.
                                        Cincinnati, Ohio
                                        Naomi P.  Barkley
                              Risk Reduction Engineering Laboratory
                              U.S. Environmental  Protection  Agency
                                        Cincinnati, Ohio
        ABSTRACT
             Many Superfund sites contain buildings, building materials, and debris
        that are contaminated with one or more toxic organic and/or inorganic chemi-
        cals.  To date, no generally applicable decontamination technique has been
        developed for the removal of organic contaminants such as polychlorlnated
        biphenyls (PCB's) from the various materials included in a modern-day struc-
        ture.  The objective of this study was to evaluate chemical and physical
        methods for decontaminating buildings and debris at Superfund sites.
             For evaluation of techniques designed to remove PCB's from concrete
        floors in buildings, concentrations of PCB's in the top 1/2 inch of a
        concrete floor In a building located at a Superfund site were determined
        before and after treatment by analyzing cores obtained from selected loca-
        tions in the floor.
             An Innovative system for decontaminating debris was also designed,
        assembled, and evaluated.  After bench-scale experiments were performed to
        determine an optimal solution cleaning PCB-contamlnated. corroded', metallic
components, a 300-gallon, pilot-scale module was designed and  field-tested  at
a Superfund site.
     The results obtained during this study were very promising,  and  the
techniques evaluated showed a great deal of potential for removing  PCB's from
concrete'flooring and from the surface of the contaminated debris.  This
paper discusses the procedures and the analytical results of both the chemi-
cal and physical decontamination techniques evaluated during this study.
-------
                                     DISCLAIMER NOTICE
oo
.t
             This  paper was  prepared as an account of work sponsored by an agency of
        the United States  Government.  Neither the United States nor any of their em-
        ployees, nor  any of  the  contractors, subcontractors, or their employees  make
        any warranty, expressed  or  implied, or assume any legal liability or respon-
        sibility for  any third party's use or the results of such of any information,
        apparatus, product,  or process disclosed in this paper or represents that its
        use by such third  party  would not infringe on privately owned rights.   The
        views and  conclusions contained in this document are those of the author and
        should not be interpreted as necessarily representing the official policies
        or recommendations of the U.S. Environmental Protection Agency or of the U.S.
        Government.
                                                                                                        INTRODUCTION
     A large number of sites  in the  United  States  are contaminated with
hazardous waste and cleanup of these waste  sites  is the top environmental
priorityof the decade.  As of this  writing,  about 800 sites are listed on
the National Priorities List  (NPL),  and an  additional 378 sites have been
proposed for inclusion on the list.   In the Superfund Amendments and Re-
authorization Act (SARA), a mandatory cleanup schedule is being considered
that would require EPA to cleanup at least 375 of these sites over the next 5
years.
     Many Superfund sites contain buildings (e.g., office buildings, manu-
facturing facilities), building materials (e.g., glass, concrete, mortar,
brick, stone), and debris'(e.g., scrap metal, pieces of wood, equipment or
furniture) that are contaminated with one or more toxic organic and/or in-
organic chemicals.  Decontamination of these items is  important in preventing
the spread of contamination off-site and In reducing exposure  levels to
future users of the buildings or equipment.  To date,  no generally applicable
decontamination technique has been developed for the removal of organic
contaminants such as polychlorinated blphenyls (PCB's) from the various
materials included in a modern-day structure.  At present, equipment 1s
usually steam-cleaned, and buildings and structures are frequently torn down
Instead of being decontaminated.
     A recent U.S. Environmental Protection Agency publication (1) discusses
various methods, including scarification, hydroblasting. and a variety of
chemical treatments for cleaning the surfaces of concrete and similar mate-
rials.  Many of these methods produce large amounts of liquid residues that
-------
rv>
oo
have to be collected and treated.   Moreover, the overall effectiveness of
these methods has not been carefully verified.  Reliable data which provide
an indication of the efficacy of either established or emerging methods of
decontaminating intact structures  and structural components are lacking.
     Therefore, the major objective of this  study was to evaluate the ef-
ficacy of currently available chemical and physical decontamination methods
for removing contamination from Intact buildings and restoring these struc-
tures to a usable condition.  Another goal was  investigation of methods that
show promise for removing toxic contaminants from debris.  A successful
decontamination method can offset  the high costs of dismantling and disposing
of contaminated structures, while  at the  same  time salvaging or increasing
the value of the reconditioned buildings, equipment, or property.
     Phase T of this study was directed toward  locating an actual contami-
nated site or sites that would be  suitable for  demonstrating various cleanup
or site remediation technologies.   Several sites  (some NPL-Hsted and some
non-NPL-listed) were visited and evaluated.  Ultimately,  two PCB-contamlnated
Superfund sites, the Pioneer Equipment site  and the Carter  Industrial site
which are less than 1 mile apart in Detroit, Michigan, were selected for
Phase  II of  this study.
      In Phase  II of this building and debris decontamination study, the
efficacy of  selected decontamination  technologies  for  removing PCBs has been
evaluated during field  studies performed at  the two contaminated  sites  1n
Detroit.  Methods  for removing PCBs on the  surface  and  in the  top I inch of a
concrete  floor at  the Pioneer site were assessed in a  comparative fashion.
      Also during Phase  II, a system for decontaminating debris was designed
and  assembled.  Bench-scale studies were conducted  In  which the optimal
solution for accomplishing hydromechanics 1 cleaning of contaminated debris
was determined.  Based upon the outcome of bench-scale studies, a pilot-scale
version of the debris cleaning system was designed and demonstrated at the
Carter site.
BUILDING DECONTAMINATION DEMONSTRATIONS AT PIONEER EQUIPMENT SITE
     At the Pioneer Equipment Site, two decontamination techniques for re-
moving PCBs were demonstrated.  These two techniques were 1) a method for in
situ degradation of PCBs which entails application of an alkali metal/poly-
ethylene glycolate mixture directly to the concrete surface, and 2) a shot-
blasting technique which entails use of steel shot to cut away concrete
surfaces.  The decontamination tests were conducted in a statistically valid
manner In order to minimize both the effects of varying PCS concentrations in
the floor and the subtle effects of variations in concrete composition Itself
on the comparison of decontamination methods.
Sampling Procedure
     Prior to Implementation of the two decontamination technologies, the
concrete floor (which is located in an abandoned building) was divided into
sections, and each section subdivided to form test plots.  Within these test
plots, sampling locations were identified for baseline (pretreatment) and
posttreatment sampling.  More specifically, the floor was sectioned off into
four 20-foot x 10-foot rectangular plots and each was then bisected to create
a total of eight 10-foot x 10-foot plots.  These plots were all in the north-
west quadrant of the north room of the building and had a north/south longi-
tudinal axis.  Five sampling locations were Identified 1n each of the eight
test plots.  Two adjacent points were marked off at each of the five sampling
locations where the first point was sampled as part of the pretreatment
-------
  sampling program and the  second  point  was  sampled  subsequent to treatment of
  the test plot.
       Concrete core samples  were  obtained using a 2-Inch  coring tool  at each
  of the five sampling locations  In  each test  plot.   Each  concrete core had a
  diameter of approximately 1.75  Inches.  From each  of these eight plots,  five
  core samples were obtained  for  a total of  40 samples.  The top 1 Inch of 24
  of the 40 samples (i.e.,  3  per  plot) were  analyzed for PCB content.  The
  remaining 16 core samples (2 from each plot) were  each divided Into  two
  sections (the top i Inch  and the next  i Inch, thus creating 32 samples)  and
  each section were subsequently  analyzed for  PCBs.    Thus, a total  of 56
^sample analyses were completed  prior to Implementing the two decontamination
oo
°*t>rocedures •
       After the completion of the two decontamination technologies, another  40
  core samples were obtained from locations  on the floor that were as  close as
  possible to the original  sampling locations.  The  samples were sectioned and
  analyzed as described for the pretreatment samples, resulting in another set
  of 56 analyses.  The locations  of the top i  inch and the next i  Inch core
  samples are shown in Figures 1  and 2, respectively.
  Demonstration of the IT/SEA Marconi Reagent:  Methodology and Results
       The chemical reagent, also called the IT/SEA Marconi reagent, is a
  polyethylene glycol-based mixture.  The reagent was Initially heated in a
  waterbath and then  applied to the concrete surface using a sprayer or brush.
  Typically,  the  reagent is allowed to  remain 1n place for 2 to 3  weeks.   In
  previous studies,  the liquid penetrated up to 2 Inches, where it contacted
  the  PCB  and reacted to form non-PCB byproducts.

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     During the technology demonstration at the Pioneer Equipment  Site,  cans
of IT Marconi reapent were heated  in a waterbath  to a  temperature  of  180°  to
190°C.  When the reagent reached the correct  temperature, a  small  amount of
hot reagent was poured onto  the concrete floor within  designated  test plots.
and was-spread evenly using  a roller.  This process of applying  the reagent
was repeated two additional  times  at 24 hours and 48 hours  following  the
initial application of reagent. The reagent  was  then  allowed to  dry  for a
period of 2 weeks.
     After 2 weeks, 20 posttreatment core  samples were collected from the
areas that had been treated  with  the Marconi  reagent  and  were analyzed for
PCBs.
     The concentrations of PCBs in the top i  Inch of concrete before  and
after the application of IT/Sea Marconi  reagent are summarized in Table 1.
The apparent reduction In PCB concentration ranges from 11 to 97 percent
(average reduction of 73 percent), and these results seem to indicate that
the reagent was able to penetrate into the concrete floor and reacted with
PCBs.  The penetration of the reagent Into concrete and reaction with PCBs 1s
supported by the  results obtained for the next i  inch of concrete, as shown
in Table 2.  In this latter  table, the percentage reduction  in PCB concentra-
tion  ranges  from  66  to 99 percent (average reduction of 91 percent).
      On the  basis of this rather limited study,  1t appears that the  IT/Sea
Marconi reagent has  some beneficial effect upon  PCBs which are on the surface
of or perhaps  contained within the upper J Inch  of a concrete floor.
      Additional studies involving more analyses  of concrete  prior to and
after application of the reagent should be performed  to corroborate  these
-------
   TABLE  1.   CONCENTRATION OF PCBs IN A SURFACE  (TOP  i  INCH) OF
       CONCRETE BEFORE AND AFTER SEA MARCOHI  REAGENT  (ppn)
Sample No.
MRl
HR2
MR3
MR4
MRS
MR6
HR7
MRS
MR9
MR10
MR11
KR12
IVJ M«3
So MR14
oo MR15
MR16
MR17
MR18
MR19
HR20
Pretreatment
52.0
6.5
22.0
5.7
8.3
6.5
9.2
42.4
22.1
23.3
33.2
21.7
50.0
19.8
39.8
4.6
8.1
60.0
10.2
12.3
Posttreatment
3.67
2.46
0.64
1.58
2.79
2.35
1.96
1.43
1.94
1.58
5.03
3.25
5.45
5.63
6.22
3.04
4.12
5.82
9.10
5.48
' Reduction
93
62
97
72
66
64
79
97
91
93
85
85
89
72
84
34
49
90
11
55
    TABLE 2.  CONCENTRATION OF  PCBs  IN A SURFACE (NEXT J INCH)  OF
        CONCRETE BEFORE AND AFTER SEA MARCONI REAGENT (ppm)
Sample No.
  MR21
  MR22
  MR23
  MR24
  MR25
  MR26
  HR27
  HR28
Pretreatment
     3.5
     5.0
     6.3
    13.0
     4.1
     1.8
     2.7
     3.0
Posttreatment
   0.23
   0.23
   0.21
   0.10
   1.41
   0.35
   0.10
   0.01
% Reduction
     93
     95
     97
     99
     66
     80
     96
     99
Initial findings.  Furthermore, additional  work 1s needed to determine the
optimum reaction conditions for the IT/Sea  Marconi reagent.
Demonstration of the Shotblastlng Process:   Methodology and Results
     Shotblastlng 1s a destructive procedure that may be used to remove
surface- layers of contaminated concrete.   By selecting the shot size and the
rate at which the machine traverses the concrete surface, one can control the
amount of concrete removed from the surface of a concrete floor.  Typically,
a 1/16- to 1/8-Inch layer of concrete .can be removed by the shotblaster.
(Note:  The shot blasting machine used in this study was Blastrac Model  1-10D
with a Model 554-DC dust collector.)  The machine is equipped with a HEPA-
fUtered vacuum system that captures nearly all of the partlculate generated
during Shotblastlng.  The captured dust 1s periodically removed from the
vacuum system of the shotblaster and transferred to barrels for subsequent
disposal.  Despite the HEPA-f1ltered vacuum system, use of the Shotblastlng
process may generate airborne debris, which has the potential for cross-
contamination of test plots.  Therefore, the Shotblastlng evaluation at  the
Pioneer Equipment Site was commenced after all activities related to the
evaluation of the IT/Marconl reagent were completed.
     Designated test plots on the concrete floor (see Figures 1 and 2) were
shotblasted and a minimum of 0.125 to 0.250 Inch of concrete was removed.
Fugitive dust generated by the process that was not captured by the vacuum
system was gathered and vacuumed separately, and disposed of as contaminated
concrete material.  Following Shotblastlng, 20 posttreatment core samples
were collected.
     The concentrations of PCBs 1n the top i Inch surface of concrete before
and after the Shotblastlng process are summarized In Table 3.  The percentage
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TABLE 3.   CONCENTRATION  OF  PCBs  IN A SURFACE (TOP J INCH) OF
    CONCRETE BEFORE  AND  AFTER  SHOTBLASTING PROCESS (ppm)
Sample ID
SB1
SB2
SB3
SB4
SB5
SB6
SB7
(\> SB8
<* SB9
^° SB10
SB11
SB12
SB13
SB14
SB15
SB16
SB17
SB18
SB19
SB20
Pretreatment
4.4
0.13
65.0
7.7
26.0
17.2
11.8
35.7
13.4
4.6
1.6
4.4
4.7
23.5
3.2
25.0
22.8
21.4
40.9
42.5
Posttreatment
3.0
1.5
2.52
3.17
2.11
6.92
5.44
6.3
3.4
3.91
1.86
2.75
1.97
1.56
1.41
4.84
1.28
5.38
8.15
7.78
I Reduction
32
-1054
96
59
92
60
54
82
75
15
-16
38
58
93
56
81
94
75
80
82
reduction in PCB concentration after shotblasting ranges from 19 to 96  per-
cent, (average reduction of 68 percent) which Indicates that the technique  is
fairly effective in removing PCBs from the surface of the concrete floor.
However, in two samples (SB2 and SB11) the PCB concentration apparently
increased after shotblasting treatment.  This apparent Increase is most
likely due to the fact that the post-treatment samples were, in the case of
these two samples, obtained from locations on the floor which were Initially
more heavily contaminated with PCBs.
     These results Indicate that 1n the case of the PCB-contaminated floor  at
the Pioneer site, PCBs In the top i to } Inch of the concrete floor are, as
expected, effectively removed by shotblasting.  Of course, further analyses
should be performed to determine the depth of penetration of PCBs Into  the
concrete.  Conceivably, the concrete could be repetitively shotblasted  until
no significant levels of PCBs remain.
     Only a small amount of fugitive dusts were generated by the shotblasting
process.  At least 95 percent of the concrete dust was captured by the  vacuum
system, which 1s an Integral part of the machine.  In total, 1000 square feet
of concrete were shotblasted and approximately a 1/8- to 1/4-Inch layer of
concrete was removed.  The total quantity of dust amounted to two barrels.
Cost Estimation of Marconi and ShotblastJnq Technology
     On the basis of the experience at the Pioneer site, a cost analysis was
performed to determine the costs of large-scale implementation of each  of the
two building decontamination techniques.  The cost of Implementation of any
technology to cleanup a hazardous waste site can vary substantially depending
on the site's location, nature, types of contaminants, availability of  the
facilities and many other variables that can unexpectedly Increase or perhaps
-------
decrease the estimated cost.   Each  hazardous  waste  site  Is atypical and
cannot be compared with any other site.   Therefore, to establish a base  1n
the cost estimation,  several  assumptions  have to be made.
     A 10,000 square  feet plot was  taken  as a base-line  area on which  the
cost estimation was performed.  These costs are based on the following as-
sumptions:  1) the site 1s within SO miles of the contractor's facility, 2)
no pretreatment cleaning is needed  to the plot, 3)  the plot does not have any
obstructions, such as debris, equipment,  or machinery, 4)  the  site has elec-
trical power and outlets.  The costs for  large-scale  Implementation of Marconi
reagent and Shotblastlng techniques made  on  the basis of the foregoing as-
sumptions are summarized in Tables  4 and  5  respectively.
     It can be seen from these tables that the cost of Marconi reagent is 85t
per square foot as compared to $2.19 for  Shotblastlng.   The Shotblastlng
technique 1s labor Intensive and generates  a  significant quantity  of contami-
nated waste, whereas 1n the case of the Marconi reagent  technique, minimal
labor 1s required and the reagent does not generate wastes.  On  the basis of
our limited experience It appears that the cost of  Shotblastlng  Is  almost 3
times higher than that of Marconi  technique.   It should  be noted that  these
costs do not Include the sampling and analytical cost.

DEMONSTRATION OF DEBRIS DECONTAMINATION:BENCH SCALE EXPERIMENTS
      In designing the debris decontamination system the  goal  was to produce a
portable, self-contained module which would  Include a component  1n which
debris could be washed using a non-toxic cleaning solution.   From the  outset
1t was felt that the debris decontamination  system should  include a solvent
reclamation system which would permit the cleaning solution to be reclaimed
and reused  thereby minimizing the volume of  contaminated liquids produced
        TABLE 4.   ESTIMATED COST OF IMPLEMENTATION OF MARCONI REAGENT
                   TECHNIQUE BASED ON 3 APPLICATIONS TO A
                           PLOT OF 10.000 SQ. FT.
          Description
                                                                 Cost
1.  Fixed rate labor (Includes cleanup technicians)               $3,500
    70 hours at the rate of $50/hr
2.  Fixed rate equipment (Includes reagent heating system,           500
    applicator)
3.  Other Direct Costs
     Expendables (Includes Marconi reagent, protective            2,900
      clothing, empty drums, miscellaneous)
     Non-expendables                                                  0
     Travel (9 $50 per diem)                                        450
4.  Disposal (approximately 2 drums 9 $125/drum)                    250
5.  General and administration  (calculated on  Item  3  0  16.11)       539
6.  Fee (fee on Item 3 and 5 8  10. OX)                               389
        Total estimated cost for  10.000  square feet             $8.528
        Cost per square foot
                                                                  $0.85
-------
TABLE 5.  ESTIMATED COST OF IMPLEMENTATION  OF  SHOTBLASTING
      TECHNIQUE BASED ON THE REMOVAL  OF  TOP 1/4  INCH
                TO A PLOT OF 10,000 SQ.  FT.
 Description
                                                       Cost
       1. Fixed rate labor  (Includes foreman, cleanup technician
           equipment operator)  180 hours at the rate of $50/hr
       2. Fixed rate equipment  (Includes rental of shotblaster,
           HEPA vacuum,  air compressor)
^     3. Other Direct Cost
i—>
            Expendables  (Includes vacuum bags and filters, micro-
             traps, protective  clothing, miscellaneous)
            Non-expendables
            Travel (0 $50 per diem)
       4. Disposal (approximately 30 drums of contaminated concrete
           0 $125/drum)
       5. General and administration (calculated on  Item 3 0 16.IX)
       6. Fee (fee on Item 3 and 5 0 10X)
               Total estimated  cost for  10,000 square feet
                                                       $  9.000
                                                         4.612

                                                         2.090
Cost per square foot
                                                        $2.19
during the debris washing process.   In order to test some of these concepts,
the bench-scale experiments  described below were performed.
     A bench-scale version of a Turbo-Washer (Bowden Industries) served as
the debris washer for the bench-scale Initial studies.  This unit Includes an
axial flow pump, a propeller shaft, a propeller, and a pressure chamber, all
housed within a heated tank  which 1s also equipped with a rotating disc for
removing oil which rises to  the surface of a protected (minimal turbulence)
segment of the cleaning tank.  During operation the Turbo Washer's pump
generates vigorous mixing of the cleaning solution by continuously redr-
culatlng the cleaning fluid  In and out of the pump.
     Using the bench-scale version of the Turbo-Washer, four cleaning solu-
tions were evaluated.  The cleaning solutions selected for evaluation In-
cluded tap water. 10 percent sulfurlc add, and aqueous dilutions of two
proprietary cleaning solutions. BB-100 (Bowden Industries) and Power Clean
(Pen)tone Corporation).  The experimental procedure Involved the application
of measured quantities of used motor oil, grease, and soil to rusted Iron
parts to simulate the kind of grime that Is likely to be encountered on oily,
PCB-contamlnated, metal parts and debris In the field.  Three tests were
performed with each cleaning solution, and a fresh set of oil/grease con-
taminated metal parts were employed for each test.  For consistency, each set
of contaminated parts was matched closely with regard to the size, shape, and
type of metal.  The parts were arranged 1n the same order 1n parts-washer
basket during washing.
     At the completion of each test, two allquots of cleaning solution were
collected, one aliquot was submitted for oil and grease analysis and another
for total suspended sol Ids analysis.  Two surface wipe samples from selected
-------
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  metal parts were also collected for oil and grease analysis  to determine the
  level of oil/grease remaining on the metal surfaces after treatment 1n the
  parts washer.  The skimmer oil from each of the three runs was mixed together
  for oil and grease analysis.
       The 'results of the oil/grease and total suspended solids analyses are
  summarized 1n Table 6.  The analytical results of the wipe samples Indicate
  that, after cleaning, the amount of oil and grease on the metal surfaces was
  significantly higher in the case of water or sulfurlc add and comparatively
  lower for BB-100 and Power Clean.  This Indicates poor cleaning performance
  of water and sulfurlc acid.  Moreover, the handling of 10 percent sulfurlc
  acid was difficult, and it also had a corroding effect on the hydromechanlcal
   cleaning  equipment.   Hence,  It was concluded that water and sulfurlc add
   should  not  be  considered as  a potential cleaning solution for oily PCB-con-
   tamlnated debris.
        On the basis  of the results of  the surface wipe  testing listed 1n Table
   6, It was concluded  that BB-100 solution  1s a more effective cleaning solu-
   tion than a Power  dean solution.  This Is shown graphically In  Figure 3,
   which plots the results of wipe samples (1n milligrams of oil and grease/
   square  centimeter) for each  run.   Table 6 results also show  that BB-100
   removed solids from metal  surfaces more effectively  than Power Clean.  The
   data also show that at the completion of  third  run,  the BB-100 solution  still
   had more cleaning  capacity to remove dirt from  metal  parts than  did  Power
   Clean.   Hence, of  the four cleaning  solutions tried,  BB-100  was  selected as
   the cleaning solution best suited  for cleaning  oily  PCB-contamlnated  metal
   parts and debris 1n the field.
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                     Figure 3.   Amount of oil and grease on metal surface
                                after completion of cleaning cycle.
     Throughput these cleaning solution  evaluations  the  Bowden Turbo-Washer
performed well.  Good agitation of  the cleaning  solution was  attained  and  the
unit performed reliably.  Therefore 1t was  concluded that  a large-scale
version of the Turbo-Washer would be used 1n subsequent  field tests.
Demonstration of Debris Decontamination:  Results  of Pilot-Scale  Tests at
Carter Industrial
     An Experimental  Debris Decontamination Module (EDDM)  was designed and
constructed on the basis of the bench-scale results.  A  300-gallon capacity
Turbo-Washer was Installed on a 48-foot  semi-trailer and the  Turbo-Washer was
modified by Incorporating a participate  removal  system and oil/water separa-
tor.  Also mounted on the trailer was a  carbon sorption  system for removing
PCBs from the cleaning solution.  Figure 4 represents a  flow-diagram of  the
pilot-scale module.  The trailer-mounted module was transported to the Carter
site for field-testing.
     During the operation of EDDM,  metallic debris Item will  be selected and
will be transferred Into the EDDM and the cleaning process will be Insti-
tuted.  The cleaning solution will  be cycled through a continuous, closed-
loop system 1n which the 011/PCB contaminated wash solution will  be passed
through oil/water separator and the clean solution will  then be recycled into
the module.  At the completion of the cleaning process,  the basket containing
the clean debris will be removed from the module.   The liquids resulting from
the decontamination of debris In the EDDM will be treated and disposed of.
     At the Carter site, two 200 Ib. batches of metallic debris were cleaned
using  the EDDM.  A solution of BB-100 surfactant was used as the cleaning
solution.  Prior to Initiating the  cleaning process five Individual pieces of
metal  from each batch were sampled  for PCBs using a surface wipe technique.
The debris Items were placed Into a basket and transferred Into the EDDM and
-------
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the cleaning process was instituted.   Each batch of debris  was cleaned for a
total period of 2 hours.  During the  cleaning process,  a portion of the
cleaning solution contained in the Turbo-Washer was pumped  through a closed-
loop system in which the oil/PCB-contaminated wash solution was passed
through the partlculate filter and into the oil/water separator.  The ef-
fluent from the oil/water separator was then recycled into  the module.  At
the completion of the cleaning process, five additional wipe samples were
obtained from the same pieces of metallic debris to assess  the post-decon-
tamination level of PCBs.  The surface wiping procedure was carried out as
described in the "Field Manual for Grid Sampling of PCB Spill Sites to Verify
Cleanup" (EPA 560/5-06/017, Hay 1986, pg 33), which entails utilization of
the hexane-soaked cotton gauze pad to wipe a 100 cm2 area on the surface of
the object being sampled.  In the case of the metallic debris sampled in this
study, the posttreatment wipe sample was obtained from a location adjacent to
the location of the pretreatment sample.  This was necessary since wiping the
surface removes the contamination and therefore if one were to wipe the same
surface after cleaning, the results obtained would be biased low.  The sur-
face wipe samples were analyzed for PCBs at the Hayden Environmental, Inc.
(formerly PSC Inc.) 1n Dayton, Ohio.
     The quantity of PCBs on the surface of each piece of metal before and
after cleaning are  summarized in Table 7.  The percentage reduction of PCBs
achieved during cleaning ranges from 33 to 87 percent  (average  reduction of
58 percent) for Batch 1 and from 66 to 99 percent  (average reduction of 81
percent) for Batch  2.  However, in the case of Sample  1  1n Batch 2, the PCB
concentration apparently Increased after the cleaning  process.  This apparent
-------
TABLE 7.  CONCENTRATION OF PCBs FOUND IN SURFACE WIPES AND BLANKS
Sample No.
Batch 1
1
2
3
4
5


Batch 2
1
2
3
4
5


Pre treatment (ug/100 cm ) Posttreatment (ug/100 cm ) S Reduction

134
490
1280
73
203
2
Blank: < 1.0 ug/100 cm

8.0
6090
374
96
1690
t
Blank: 1.0 ug/100 cm

SO
178
8S6
43
23

Average * reduction:

13.0
1800
128
10
18

Average t reduction:

63
64
33
41
87

58

-63
70
66
90
99

81
Increase Is  most likely due  to  the  fact  that  the  posttreatment wipe sample.
In the case  of this sample,  was obtained from a  location on the debris sur-
face which was Initially more heavily contaminated with PCBs.
     The results also Indicate  that the  quantity of PCBs removed during
cleaning-of Batch 2 was greater than that of Batch 1.  The reason for better
cleaning results for Batch 2 could be due to the following:  In the case of
Batch 2, after 1 hour of cleaning the basket containing the debris was re-
moved from  the washer and the parts were manually rearranged so that all the
sides of debris were exposed to the cleaning solution with the same force of
the  turbo washer.  The basket was then  lowered back  Into the washer and
cleaning was  continued for  1 more hour.  However.  1n the case of Batch  1. the
cleaning process was continued  for 2 hours without rearranging the debris In
the  basket.
      The  surfactant  solution In the  Turbowasher  was  sampled twice during the
 actual  cleaning process  and the concentration of PCBs  found were 928  ug/1 and
 420 ug/1.   Following the completion  of  the debris washing  experiment  the
 cleaning solution was  pumped through a  series of particulate  filters  and
 finally through activated carbon.   The  PCB concentration was  reduced  to 5.4
 ug/1 during this treatment. Most municipalities allow water  containing <1
 ug/1 PCB to be sewered and this level  can reaidly be achieved by cycling  the
 process water through carbon a second time.
 Conclusions
 BUILDING DECONTAMINATION AT PIONEER SITE
      The results obtained using the IT/SEA Marconi reagent indicate the
 reagent has some beneficial effect upon PCBs which are on the surface of or
 perhaps contained within the upper 1/2 inch of a concrete floor._ However.
-------
ro
vo
ON
additional  studies  should  be  performed to corroborate these Initial findings
and also to determine the  optimum reaction condition for the Karconi reagent.
     The results obtained  In  evaluating  the shotblastlng technology Indicate
that the technique  Is useful  for removing PCBs from the surface of a concrete
floor.  PCBs in the top 1/4  to 1/2  Inch  of the concrete floor at the Pioneer
site were effectively removed by shotblastlng.  Further analyses should be
performed to determine the depth of penetration of PCBs into the concrete.
Conceivably, the concrete  could be  repetitively shotblasted until no
significant levels  of PCBs remain.

DEBRIS DECONTAMINATION AT  CARTER SITE
     Evaluation of the pilot-scale  EDDM  yielded very promising results.  PCBs
were apparently very efficiently  removed from the surface  of the contaminated
debris.  Additional pilot-scale tests  should  be performed  In order  to optimize
the performance of the EDDM.
                                                                                                                                                                                        .-8
                                                                                                       ACKNOWLEDGEMENT
                                                                                                            This research was funded in its entirety by the United States
                                                                                                       Environmental  Protection Agency's Risk Reduction Engineering Laboratory under
                                                                                                       Contract No.  68-03-3413. Work Assignment No. 25. Naomi Barkley, Project
                                                                                                       Officer.  PEI  Associates. Inc..  Cincinnati, Ohio, was the prime contractor
                                                                                                       with subcontractor support from Radian Corporation (sample analysis) and IT
                                                                                                       Corporation (IT Corporation has  exclusive rights to the SEA Marconi Reagent).
                                                                                                            The authors wish to acknowledge the assistance of Mr. Ralph Dollhopf,
                                                                                                       EPA Region V On-Scene Coordinator for the Pioneer and Carter Sites.
                                                                                                                                     REFERENCES
                                                                                                    1.   Esposlto, M. P., J. 1. McArdle, A. H. Crone, J. S. Greber. R. Clark.
                                                                                                         S. Brown. J. B. Hallowell, A. Langham. and C. 0. McCandlish.  Guide for
                                                                                                         Decontaminating Buildings. Structures, and Equipment at Superfund Sites.
                                                                                                         EPA Report No. 600/1-85/028. U.S. Environmental Protection Agency,
                                                                                                         Cincinnati, Ohio, January 1985.
                                                                                                                                    KEY-WORD  INDEX
                                                                                                                                    Remediation
                                                                                                                                    Decontamination
                                                                                                                                    Superfund
                                                                                                                                    PCS
                                                                                                                                    Concrete
                                                                                                                                    Debris
                                                                                                                                    Chemical  Reagent
                                                                                                                                    Shotblastlng
-------
            DEVELOPMENT OF SITE REMEDIATION TECHNOLOGIES
                           IN EUROPEAN  COUNTRIES
                                 Thomas J. Nunno
                                Jennifer A.  Hyman
                         Alliance Technologies Corporation
                                   Bedford,  MA
                                       and
                                 Thomas Pheiffer
                       U.S. Environmental Protection Agency
                   Office of Program Management  & Technology
                                 Washington, D.C.
                                    ABSTRACT

Site  remediation  is a pressing  issue in European  countries due to limited  availability
of land.  Therefore,  much progress  is  being  made  in the development of effective
technologies for remediating  contaminated sites.  The purpose of this  program was to
investigate the most  successful  and  innovative technologies  for  potential  application
into  US markets.  This EPA-sponsored project  was based on a 9-month research effort
which   identified  95  innovative  technologies  in  use  or being researched  in  foreign
countries.   The  most promising  technologies were studied in-depth through  personal
interviews  with  the engineers who research  and apply  these technologies, and  tours of
laboratory   models  and   full-scale  installations.    The  most   successful  full-scale
technologies  investigated  were  developed in  Holland,  West  Germany  and  Belgium.
These   technologies  include  vacuum  extraction  of  hydrocarbons  from soil,  in situ
washing of cadmium-polluted  soil,  rotating  biocontactors  for treating  pesticides in
ground  water,  high-temperature  slagging incineration of low-level radioactive  wastes,
in situ  steam stripping,  and a  number  of  landfarming and  soil washing  operations.
The  paper provides description of 13 site remediation techniques that have shown such
promise in  laboratory studies or  in  practice to warrant consideration  of their use in
the United States.

INTRODUCTION

The  following  paper summarizes  the   results of  a   9-month  study  by  the   U.S.
Environmental  Protection Agency's  Office of  Program Management and Technology.
The  purpose of this EPA program was to identify and  assess international technologies
applicable  to  hazardous  waste  site  remediation in order  to promote  their use in the
United  States.  The program was  conducted  in two phases:   1) Phase  I  -  Technology
Identification  and  Selection;  and  2)  Phase II  - Technology Review.   This paper
summarizes  the results of Phase II of this program, a  detailed investigation of the most
promising technologies identified by the Phase  I efforts.
                                 297
-------
 The  Phase  II  investigation  of the most promising  technologies was  accomplished by
 interviewing scientists and engineers  who  are researching or have extensive experience
 with  each technology.  Meetings  at  laboratories,  facilities  and  site  installations were
 scheduled  by  Alliance  or  organized  by  the  coordinators of  treatment technology
 research  in  each country.  Key coordinators from  foreign countries include Ms.  Esther
 Soczo', Coordinator  of Soil Development at The National Institute of  Public Health and
 Environmental  Hygiene (RIVM),  the major  government research center in  Holland;
 Dr. lr. K.  J.  A. de  Waal, Deputy  Director of  TNO (Netherlands  Organization for
 Applied  Scientific  Research); and  Mr. Christian  Nels, Director  of  Research  for
 Umwehbundesamt, (Federal Republic  of Germany's equivalent to  U.S. EPA).

 OVERVIEW OF SITE REMEDIATION PROGRAMS IN EUROPEAN COUNTRIES

 Although  the Phase  I  efforts reviewed  site remediation technologies  from all  parts of
 the world outside  the  U.S.,  the  Phase II  investigation focused  on  technologies in
 Holland,  Belgium, and Federal Republic of Germany.  Other countries such as France,
 Italy  and  Denmark  are performing extensive technology development.  However, much
 of this   work   is  already  being documented   by  the NATO/CCMS  Pilot  Study
 Demonstration  program.1   The  Phase  I  Technology  Indentification  and  Selection
 Report2 summarizes   the  status   of  site  remediation  programs  and  technology
 development  in many countries.

 Site cleanup  criteria, developed in  Holland, have served  to promote the development of
 full-scale  site  remediation  technologies   in  that  country.   In  addition,  the  other
 countries   (Federal Republic  of  Germany  and a province in  Canada) are using these
 standards  as guidelines  in  evaluating  cleanup  goals.   The  Dutch   government  has
 developed three sets of soil  concentration  levels for hazardous contaminants  which are
 used  as guidelines for prioritizing site  remediation.   Table 1  gives  examples of the
 three reference  levels designated  A, B, and C.
                      Ttl.E 1. DUTCH IC'CltiCE IfVIIS USEC '01 TH£ JUD6»tkT
                             0' SOU COoTtmiitT ion
                                                    Concentration lewei
                                                    (•9/«9 ory «ci«nt)
                    Component
•olycyclic aromatic hydrocarbons 
-------
SUMMARY OF PHASE II RESULTS

The    field   team   visited   12 research   groups,   consultants,   and  manufacturers   at
15 locations  in  three  countries  in  Europe.  The  site  visits,  conducted from  March 21
through  April  2,  1988  during  the  Phase II  effort,  are  summarized  in  Tables  2,  3,
and 4.
t.OK J. tell W.truog intututionl VitnM Oy •MHincvC 0» twin Turn In M.rch 1III m IM Nttrxjruno. •»« m. F.o.r.l M(H«l.c of COT..-,
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                                           299
-------
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In   general,   the   Phase II   efforts   were  successful  at   identifying   site   cleanup
technologies not  currently  used  in the  United States, as well  as unique applications  of
techniques  used  in  the  United States.   Among  the most  important Phase II findings
were  five  different soil  washing  techniques  in  Holland and the  FRG.   Another key
finding was the  High Temperature Slagging Incinerator  (HTSI)  technology reviewed  in
Belgium.   In addition,  the field team reviewed unique  applications of in  situ  biological
treatment  and  composting  techniques,  vacuum  extraction  and  in  situ  air  stripping,
in situ extraction of  cadmium  from  soils,  application  of rotating biological contactors,
and electrochemical dehalogenation techniques.

All  of  these unique  applications   and  research  should  contribute significantly  to our
knowledge  base  of site cleanup  technologies in the  United States.  The results of  Phase
II site  visits are summarized  below.
                                       300
-------
Soil Washing Equipment Findings

The field team reviewed five high throughput soil  washing technologies in Holland and
the FRG.  Characteristics of these technologies  are  summarized  in Table 2, including
throughput, unit  operations, reject particle size, and costs.

A key  similarity among  all of the units was that they operate on  the  principle that
most  of the  contaminants are sorted  to the fine materials (<63 um) and  segregation of
these materials   from  the  other size  fraction  "cleans", the soil.  Some  of the units
(i.e.,  the Heijmans unit),  employed  very  simple  particle  separation and  wash  water
treatment  technologies,  .while  others  (Harbauer  and  Oil  CREP)  employed  more
sophisticated extractants and cleaning  agents.  A major consideration of all washing
techniques is the  fact  that as  particle reject  size  decreases, so  does  sludge residue
generation.   Cleaning efficiency tends  to  decrease with decreasing particle reject size
cuts as  well.

Although it  is impractical  to discuss the details of each soil washing technique  in this
article,  a brief   discussion of the  HWZ soil washing operation  in  Amersfort, Holland
will  serve  to illustrate a typical soil  washing unit.  The HWZ unit was  approximately
the median  in size  and complexity  of unit operations among  the soil  washing units
investigated.   One atypical  feature of  this unit is that 30  percent of the wash  water
was  discharged   to a  nearby  estuary,  whereas  many  of  the   other  units employed
100 percent recycle of wash water.

The  HWZ soil cleaning method is based  on techniques of soil washing  and particle
sizing, along with  a  water treatment  stream.  A  flow schematic  of  the system is shown
in Figure 1.
                                  t. MWZ Mil
                                  301
-------
After  first  crushing  the   larger  pieces  of rubble,  pieces  4 mm < x < 50 mm  are
separated out of the stream by wet sieving.  Soil particles 63 um < x < 4 mm comprise
the  main  soil  stream.   These  particles  are washed of adsorbed  contaminants  by
scrubbing with  detergents and  adjusting the pH to 12-13  by addition of NaOH.  The
HWZ  soil scrubber employs two  mixing  propellers,  one  mixing up and  the  other
mixing down, with  a  net  flow  downward.  A  hydrosizer then removes  low density
organic and  carbon particles such as wood and rubber.  After  a  dewatering step,  the
remaining  sand  (63 um  <  x < 4 mm)  is  often clean enough  to  be used  in  asphalt
batching, or else  it  must be  landfilled.   The  fines  (<63 um)  are separated  by
hydrocyclones  and dewatered  in  a  belt  press.   The   remaining contaminants  are
concentrated in  this small volume of fines and it is disposed of as  hazardous  waste.

The contaminated  scrub  water and the overflow  from the wet sieves,  hydrocyclones
and  belt  press  are cleaned  in the  water  treatment  stream.  After residual fines  are
removed  by sedimentation,  the  water  is  treated  in  a  tank  by  precipitation,
neutralization,  coagulation,  and  flocculation  to remove  the  dissolved  contaminants.
Cyanide  can  be  removed here by  the addition of ferrous sulfate.

In  the last  steps  of the water  treatment stream, floating iron hydroxide particles  are
removed  by  sand  filtration, and dissolved  organics by activated carbon.  The  cleaned
water  is then  discharged  or recycled as shown in  Figure 1.   The  treatment of  soil
contaminated with bromine  compounds  has been successful on a  laboratory-scale,  but
has not yet been tested on a full scale.

In  general,  pollutant  levels  and  removal  efficiencies  achievable  by soil washing
strongly  depend on the distribution of  the  pollutants over the different size fractions
and  the  presence  of soil  particles other  than sand  (such as adsorbing clay and carbon
particles)  which are  difficult to wash.   The contaminants  trapped  in  the clay clumps
cannot be reached by scrubbing,  but  if  crushed, can  be taken  out  in  the sludge.
Where the amount  of  fine  fractions <63  um  is greater than  20 percent, the volume
reduction of  the contaminated soil  is generally not sufficient to warrant  treatment.

Most of  the  soil  washing  companies noted that  their  practical upper  limit of fines
(<63 um)  was 20  to 30 percent  in  the  soil to be  cleaned.   Because the proportion of
fines present increases the  generation of sludge, treatment costs tend  to increase  for
finer  grained  soils.   The   Harbauer technology shows  an advantage of  potentially
generating  less sludge;  however, the additional costs of wash water treatment employed
for  that   technology make  it  slightly  more  expensive  than  the  other soil washing
technologies  reviewed.

Heijmans, which is among  the  more simply designed systems, accepts  soils  with fine
fractions <63 um  up to 30  percent,  but  their process works best on sandy soils with  a
minimum of humus-like compounds.  Because no sand  or charcoal filters are employed
by  Heijmans,  the  system  is  not  able to  treat  such  contaminants  as  chlorinated
hydrocarbons or  aromatics.   Like most  soil washing techniques,  the throughput and
cost  of treatment  is dependent  on quantity of fine fractions (<63 um) in the soil to be
cleaned.
                                 302
-------
The  Heijmans  system  has  had  its  greatest  success  treating soil  contaminated  by
cyanides (CN).   Heijmans  adds  hydrogen peroxide (H2O2)  into the scrubber to  react
with CN  to form C02 + NH4.   In  one  experiment, CN at a concentration of 5,000  to
6,000 mg/kg  dry  soil  was  reduced  to 15 mg/kg.   A  table showing  the results  of the
Heijmans  soil  washer  on  seven  different  types  of  contaminated  soil is shown  in
«^_i.i_ *
Table 5.
                        TAIK S.  IfiULTI or IOIL CIEANIICS HlfOIHJO IT KCUNAKI
                                • UltUtlCNmtC I.V.* (Antlyiti performed by in
                                Independent laboratory)*
Site
CelvenUing
Fuel drilling
Gel vani i ing
CatHorkt
Catvorki
Diesel fuel
Cel vani I irg
'Source: Reference
Soil type
Silt
Sand
Coarse sand
Pine land
Mne sand
Coarse sand
Silt
Hne aani
Coarse sand
4, .MU..«,
Conteolnent
Total cyenide
Chroae
nickel
Zinc
Caroline
Total cyanide
Chrome
Cadmium
Copper
Niciel
lead
total cyanide
Total >CAt
Mineral oil
Total cyanide
line
E nil ieutechni vk b.
Iffert
(•»/«!)
250- $00
43-45
250-890
460-720
1,000-7,000
400-1,000
100-2, SOO
4-18
100-250
100-60:
100-450
80-220
250-400
3,000-8,000
75 -JOC
160-170
v. lodemiener Inc.
1«8!.
After
10-15
11-15
40-70
140-200
80-120
6-10
70-120
0.5-1.4
25-6C
2C-7C
5 15
0.5-10
90-12C1
7- 10
sc -a:

Vendor supplied  cleaning  efficiency  data for  the  other  four  soil washing  units are
summarized  in  Table 6  for a variety of contaminant  types.  In  general,  the  efficiencies
for heavy  metals and cyanides are similar among the units. The OIL  CREP unit tends
to be  more  efficient for  hydrocarbon  wastes and the  Harbauer unit has  advantages  in
soils with higher  clay content.
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                                     303
-------
High Temperature Slagging Incineration (HTSH

The Belgium  HTSI  technology shows promise  as  a transferable technology  for  high
hazard  waste  streams  and  fibrous  asbestos  wastes.  Details of this technology  are
summarized  in  Table 3.    Very  high  combustion  efficiency  and  offgas  cleaning
efficiencies along with very stable slag residues  make this technology very attractive.
The  high  treatment costs S3.50/kg  ($1.60/lb)  associated with  the  low throughput
60  kg/hr (133 Ib/hr) unit  make  the  development of higher throughput units critical to
successful importation to the United States' market.

Other Unique Applications of Site Remediation Technologies

During  the  trip,  many  other   successful  applications  of  conventional and  novel
treatment technologies  were observed, on both a  research scale, as well  as full-scale.
Table 4 outlines the  important characteristics of these technologies.

Biorestoration  research  and full-scale applications of bioremediation technologies  have
advanced  in  European countries  much as it  has  in the  United States.   During  visits
with  two  research organizations  (TNO and RIVM)  and three consulting companies, the
field  team observed  many successful  studies  and  applications of biological  treatment
technologies, mostly  aerobic systems.

In situ  bioremediation  was  being researched  and  tested  at  RIVM and applied by
Heidemij  in Holland.  RIVM found that hydrogen peroxide was  a suitable oxygen
source  for  in  situ  bioremediation.  Biodegradation  rates  of 10 mg C/kg day   were
obtained by RIVM.   At a  contaminated  gasoline site, bioremediation will be  used Tor
cleanup to  the  Dutch "A" limit of 20 mg/kg.

Onsite  bioremediation  technologies  are being  researched  and applied in  both  Holland
and the FRG.  TNO showed  successful  results  from laboratory experiments  for  both
wet  slurry  biological  treatment  systems   and  dry  compost-type  systems.   This
fundamental  research  showed  diffusion  of  organics from the soil  particles to be the
rate limiting step.  Full-scale  applications of compost-type systems  were being applied
by  both Heidemij (Holland)  and Umweltschutz Nord (FRG).   Costs  for  full-scale  ex
situ composting applications were reported to be  in  the range of S82 to S136/ton.

A Rotating Biological Contactor (RBC) application employed by TAUW in Holland was
used  on pesticide-contaminated ground water  containing  chlorinated organics.  TAUW
found that the RBC system reduced  activated carbon requirements  by 92 percent, and
decreased remediation costs by 30 percent.

Other  physical/chemical  treatment research reviewed  included  an  in situ   cadmium
extraction project by TAUW and an  electrochemical dehalogenation  research project  by
TNO.   The cadmium extraction  project employed in situ  hydrochloric acid leaching of
cadmium  from  over  30,000 m3 of  soil.   The  acid leachate  was  purified  by  ion
exchange  and  reused.  The treatment cost was  estimated to  be  $75/ton  of soil.  The
electrochemical dechlorination  research is currently nearing the end of the bench-scale
phase.  The  potential  application  to  site remediation  is in  the detoxification  of
complex organohalogens  in the  aqueous phase.   Current costs are  projected  to  be
$0.023/gal.  Full-scale research will begin June 1988.
                                  304
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Numerous  full-scale projects  involving in situ vacuum  extraction and air stripping of
volatile contamination were reviewed  in  the FRG.   Hannover  Umwelttechnik (HUT)
has installed over  300 vacuum  extraction systems for vadose  zone decontamination.
HUT has  also developed a unique in  situ air stripping system  for removing  volatiles
from  ground  water in conjunction with  vacuum  extraction.  Treatment costs  for the
HUT system are less than 10 DM/tonne (S5/ton).

CONCLUSIONS AND  RECOMMENDATIONS

Soil  washing  experience  in the Netherlands and  the  Federal  Republic of Germany
(FRG)  has shown that soil  washing  can  be  conducted on a  large-scale  at  costs
substantially  lower than   those  of  incineration  (with  notably  less  effectiveness).
Although  most of  the technologies generate 10 to 20 percent of the initial volume as
sludge,  depending  on  the  fines' content, work  is  being conducted  in the  FRG to
improve  effectiveness  of  soil  washing  on  fine materials and  to   reduce  sludge
generation.   Typical   cleaning   efficiencies  for   soil  washers   ranged  from  75  to
95 percent removal, depending on  the  contaminant.  Although the authors believe that
soil  washing   technologies  could   be   used  effectively   in the  United  States  to
significantly  reduce landfilling of  CERCLA site  soils,  it  is  unlikely that domestic or
foreign  companies  will  invest  in  this market  unless  a  uniform  set of soil  cleanup
criteria  are developed or technology based  criteria are established.

Biological treatment technologies have  been shown to  be  useful  both for polishing to
lower  concentrations   using in situ  treatment,  and   for  gross  removals  of   organic
materials  using  RBC and  composting  systems.   Efforts should  be made to encourage
the use  of these types of systems in the United States.

High  temperature  slagging  incineration   appears  to  be   a  viable  technology for
application  to  high hazard wastes and   asbestos  waste  in   the  United States.   The
licensing and construction of units  in the  United States  should be tracked to encourage
evaluation of domestic installations.

In situ  vacuum extraction of volatile organic compounds is a  well-known technology in
the United States.  Applications  in the FRG include the use  of  in  situ  air stripping of
volatiles from  ground water into the  vadose zone   and  their subsequent  removal by
the extraction wells.  Such  vacuum extraction  applications and  other innovations such
as bioaugmentation  should be encouraged in the United  States.

The apparent  success of this  relatively short-duration,  technology  assessment program
indicates  that despite  the wealth of information available in the United States,  there
is  much  to  be  learned  from  ongoing   work   in  foreign  countries.  The   authors
recommend  that  further efforts  be made to encourage the  transfer of European site
remediation  technologies  through  improved  literature  dissemination  and  seminar
presentations at symposia.  It  is also recommended  that  results  of research identified
under  this  project and  the  NATO/CCMS • Pilot  Demonstration  program be closely
monitored over the next  few years.
                                  305
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ACKNOWLEDGEMENTS

The EPA  project  upon  which  this paper  is  based  was sponsored by  Mr. Thomas
Devine,  Director  of EPA's  Office of  Program Management  and Technology.  The
authors would like to  acknowledge the  efforts of the EPA Technical Monitor, Mr. Ed
Opatken of EPA's  Risk  Reduction Engineering  Laboratory for his technical direction
during  the  Phase I and  Phase II  efforts.  Special  thanks is given  to  Mr. Donald
Sanning, also with  RREL,  whose  comments  on the  Phase  I  report  and European
contacts proved very valuable to the project.

The  authors  acknowledge  the  cooperation  of  all  the  EPA  research  laboratory,
enforcement, and  regional personnel, who  contributed  to  the  Phase I document.  The
authors also  wish to thank Ms. Margaret  Brown of Berlin, FRG and all the foreign
researchers and cleanup firm contacts who contributed to the Phase II field efforts.

REFERENCES

1.   NATO/CCMS  Pilot  Study:   Demonstration  of Remedial Action Technologies for
     Contaminated Land  and  Ground Water.   First International Workshop, Karlsruhe,
     Federal Republic of Germany.   March 16-20,  1987.

2.   Nunno,  T.J.  et al.   "Assessment  of International Technologies  for  Superfund
     Applications  -  Technology  Identification and  Selection."   Final  Report.   EPA
     Contract No. 68-03-3243.  March 1988.

3.   Nunno,  T.J.,  and  J.A.  Hyman.   "Assessment of  International Technologies For
     Superfund   Applications  -  Technology  Review  and  Trip  Report  Results."
     EPA/540/2-88/003.  September 1988.

4.   Heijmans Milieutechniek b.v. Bodemsanering.  "Installatie Voor Het Reinigen Van
     Grond".  Translated brochure.  January 1988.

5.   Harbauer GmbH, "Harbauer Soil Cleaning Process".  Undated.

6.   Heidemij  Uitvoering,   "Procestechnologie,  Heidemij   Uitvoering".   Brochure.
     Undated.

7.   Breek,  H.C.M.  Written   correspondence  to  J.  Hyman, Alliance  Technologies
     Corporation.  March 16,  1988.

8.   TBSG   Industrievertretungen   GmbH.   Written   correspondence   to  J. Hyman,
     Alliance Technologies Corporation.  May  4,  1988.

9.   Vanbrabant,  R., and  N. Van de Voorde.  "High  Temperature Slagging Incineration
     of Hazardous  Waste."  2nd  International  Conference  on   New  Frontiers  for
     Hazardous  Waste  Management  Proceedings.  Pittsburg,   PA.  p.  40.  September
     27-30, 1987.
                                  306
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HARBAUER SOIL CLEANING SYSTEM
                    by
                 Margaret Brown
                Kemmer/ Harbauer
                 Presented at:

Workshop on Extractive Ireatment of Excavated Soil: December 1 -2, 1988

               Edison, New Jersey
                     307
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                    HAPBAUER SOIL  CLEANING SYSTEM
1. SUMMARY
The system to be described is an extractive soil washing
system, the HARBAUER FBI and PB2, which since July 1987
has been in operation at the former Pintsch oil refining
facility in Berlin. To date 5000 tons of soil from the Pintsch
site itself and 6,500 tons of soil from other selected sites
have been cleaned by the unit. Experiences and results from
these soil extraction operations will be outlined.

2. INTRODUCTION

Level of contamination at the Pintsch site was medium to
extremely high in both the soil and the ground water as the
result of refining/recycling of used oils which in some cases
were contaminated by PCBs, solvent and other chemicals.

The primary pollutant groups which were found in both soil and
ground water were: Mineral oil, halogenated hydrocarbons,
polycyclic aromatic hydrocarbons, polychlorinated biphenyls
aromatic hydrocarbons and phenols.

In addition polychlorinated dibenzodioxine and dibenzofuran
were found.

In order to control the immediate danger and limit the release
and spread of contamination through dust aridxair emissions as
well as further contamination of the ground water, the Senate
of Berlin initiated a clean-up program in the fall of 1984.

The firm Kemmer/Harbauer was responsibility for the majority of
the clean-up activities on the site.
Major activities included:

Demolition of existing buildings which were contaminated not
only from process activities but with dioxins as a result of a
fire on the site.

Escavation of soil, removal of existing tanks, equipment,
digging out and removal from overflow trenches and ditches.
(Much of this work was carried out in maximum level protective
clothing.)

Providing decontamination stations and protective clothing for
all employees and vehicles.

Design, building and operation of a ground water treatment
plant.
                                 308
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Design, building and operation of a soil cleaning plant.
The soil cleaning facility has been in operation since July
1987 and has in the framework of a Demonstration project under
the auspices of the Berlin Senators for Building and City
Planning successfully cleaned 11,500 tons of soil.

Many of the previously listed activites such as demolition and
removal of existing tanks and oil supplies were carried out as
emergency measures however with the beginning of the soil
cleaning activities the real remediation of the site is being
realized. Soil escavated and cleaned is refilled on site with
treatment of extractant residues in the adjacent ground water
facility and subsequent release of effluents directly into the
nearby canal.

3. FUNCTION AND COMPONENTS OF THE HARBAUER SYSTEM

The principal process steps of the Harbauer system can be seen
in the schematic diagram of the plant.

The entire facility -WHICH ONE SHOULD NOTE IS A CLOSED SYSTEM-
can be seen as divided into four basic operations:

- Soil preparation and extraction or clean-up
- Clean-up of process waters
- Treatment/dewatering of remaining sludges
- Removal and cleaning of exhausted air emissions

After separation and sorting of large materials and grinding
and sieving of the remaining soil to a particle size of 60mm
the soil is mixed with extractant and through the application
of mechanically produced energy is subjected to vibration which
releases the pollutant from the soil and allows it to be
separated into the liquid or extractant medium. The amplitude
and frequency of the vibration can be controlled as well as the
forward speed of the sample to produce the ideal energy density
to optimize efficiency of separation. The efficiency of the
energy can also be enhanced by the use of cleaning agents
(basically biodegradable detergents)
Through multi-step rinsing, separation and dewatering
operations the cleaned soil particles are recovered from the
extractant medium and removed as clean product. The lower limit
of particle size for this separation is 15u and as such
REPRESENTS THE STATE OF THE ART FOR SOIL WASHING.
No other system is capable of separating particles in this
range. Operational costs and requirements for both the initial
                                  309
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separation and the subsequent separation and dewatering of
sludge increase disproportionately with decreasing particle
size. When Harbauer began our project the limit was 63u. We are
now investigating, under a joint research project with the
Ministry for Research and Technology and the Land Berlin
whether it is feasible, technically and economically, to
achieve an even finer separation;in the range of lOg.
Following the extraction step the dislodged pollutant is found
in two phases - as very fine particulate pollutant (less than
15u) and as a solution or emulsion in the water or extractant
phase. The water soluble pollutant phase is fed into the ground
water treatment plant where it is concentrated in a four step
cleaning process:

- Oil Separation

- Flotation

- Desorption

- Filtration and adsorption on active charcoal

The secondary residues of the water treatment process are oily
sludges, flotation sludge and loaded charcoal.
The pollutant which occurs as particles in the water/sludge
suspension is recovered together with with the fine particle
fraction following separation from the larger clean soil
particles. This fine phase is dewatered with a filter band
press. The amount of residual sludge is dependent upon the
particle size distribution of the input material and for the
soils processed to date is between 5% and 10% of the input.
The pollutant level of this residual sludge is determined
primarily by the solubility of the pollutants present.
Pollutants such as heavy metals with relatively low solubility
result in an enriched sludges whereas organics with high
solubility such as benzol result in comparatively low loading
of the sludge.

The disposal method of sludges is at present in a landfill but
investigations are underway to find another treatment method
(eg. chemical, fixation, thermal).

Light materials in the soil such as tar, -wood, roots and
charcoal particles will be separated by upward current
classification.

Because of environmental and worker safety reasons the
                                   310
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individual process components for the first three process steps
have an air removal system so that the contaminated exhaust air
is fed directly into the air stripping tower of the water
treatment plant in step four. Air cleaning is achieved through
a two step, process using wet scrubbing with subsequent charcoal
filtration and regeneration.

In this step any separated volatile materials are recovered as
solvent mixtures and incineration.is the indicated method of
disposal.

In the event that a planned crushing unit is added it will be
necessary to have a dry air cleaning system (dust filter) to
collect emissions and these residues should then be treated by
solidification.
DEVELOPMENT OF THE UNIT

The principal elements of the soil washing facility are shown
in the attached schematic.

A lab scale unit was used to determine the feasibility of
separating pollutant from soil and subsequently recovering
cleaned soil through separation and dewatering.

Successful results were obtained from the laboratory
demonstration phase between Nov. 1985 and July 1986 and it was
determined that a full scale application was then feasible.
Because of the non-homogeneous nature of soils, the variety of
particle sizes, moisture contents,and textures as well as the
many variations of pollutant type and concentration that one
may encounter the clean-up of contaminated soils is extremely
complicated. To accomodate this variable and complex matrix a
multi-step or modular system was developed to provide
additional flexibility to the total system design.

Through this modular approach it was possible during
developement to adapt and optimize individual modules based on
operational experience. This resulted in a system with a high
degree of flexibility to respond to changing input parameters.

The first unit was built in September 1986 and consisted of two
basic segments:

- Mixing of the soil with extractant in a blade washer and
subsequent extraction by vibration.

- Material separation and rinsing using a sedimentation tank,
blade washer filter band press and drying beds.
                                    311
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The first full scale unit (FBI) proved, as the lab scale work
had indicated that separation and recovery were possible but
the particle size separation limit for this initial unit was
130u; which for the high clay content soil at the Pintsch site
meant up to 40% residual sludge volumes. Therefore after a
relatively short time the unit was extended to include an
additional steps for the separation of fine particles.
(Sonnen,1987)

These additional elements (PB2) included a multi-step
hydrocyclone, which separated particles down to 15u/ and a
filter band press for dewatering of the residual sludge.

Because the producers of the individual components had no
experience with such an application the units had to be
optimized on site based on the results of an extensive
measuring system. A number of major parameters for these new
elements, which were critical to the overall efficiency of the
unit, had to be adjusted as indicated below.

HYDROCLONE UNITS -
- optimization of relationship between the input and output
  jets of the series of hydroclones,
- optimization of pressure relationship and throughput volumes,
- adjustment of the feed pumps,
- avoidance of clogging.

FILTER BAND PRESS -

- Determination of the optimal flocculating agents,
- Extending wearability in the presence of high mineral content
  sludges.

Having finished the developement of the PB2 a test run of
10,000 tonnes was made over a three month period for a variety
of soils. These soils were obtained from the following types of
sites:

Site of former chemical production/refining companies,

- Waste oil refining facility

- Tar chemistry facility

- Paint fabrication facility

The primary pollutants found in these facilities were:
Hydrocarbons
Chlorinated Hydrocarbons
                                  312
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Aromatic and Polyaromatic Hydrocarbons
PCBs
Phenols
Sites of former gas works,

- HKW Moabit

- Eisstadion Wilmersdorf

Primary Pollutants for these sites were:
Hydrocarbons
Polyaromatic hydrocarbons
Phenol
Cyanide


The 10,000 ton evaluation showed that additional refinements in
some areas could be made to increase clean-up efficiency and
operational safety. These areas were as follows:

- Additional separation step for selected "Light" materials
  (charcoal, wood, tar)
- Further separation and clarification in the fine particle
  area
- Additional measuring and control of process parameters to
  achieve optimum operating conditions

The current development stage(PB3) will include the following
changes/additions in order to address these parameters.
                                  313
-------
- Upward current classification to separate light materials.

- Thickening and Clarification for phase separation of the fine
range.

- Changed water cycles

- Introduction of additional clarifying technologies and dose
possibilities  for the ensuing process steps.


The PB3 with these changes was finished the end of August and
began a test period of continuous operation in September to
perform addition runs to evaluate the PB3.
5. Clean-up Efficiency

Results from the clean-up of the various soils is shown in the
attached diagrams. In addition to the soils mentioned,under
section soils containing mercury were also processed.
(See ABB 3)
6. Further Development

Using the outlined systematic solution it is possible to clean
soil with complex pollutants and problematic particulate
composition in such a way that the cleaned soil may be refilled
and reused.

We now have experience and results from a relatively broad
range of sites ( former chemical/physical facilities/ gasworks,
heavy metal contaminated earth). Nevertheless there is still a
need for further research and development to evaluate the total
picture for abandoned site clean-up; in light of the
non-homogeneous nature of these sites and the unique character
of each clean-up problem.

The actual potential for development lies in the treatment of
the fine and medium clay fraction (material with particle sizes
under 15n) as well as in improving the separation ,
clarification, dewatering and transport aspects. These are the
main points of the ongoing research and development project as
shown in the particle size chart.
                                 311
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Based on the positive results so far one can assume that with
the latest developments of the PB3 and the planned final stage
for PB4 based on testing of the PB3; one should have a unit
capable of handling the majority of abandoned sites in a
systematic way using an environmentally safe and economically
feasible technology.
                                  315
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CLEAN-UP  RESULTS FOR SOILS  FROM:

(1)  Former Oil Recycling  Facilities
(2)  Former Paint Operation
        Chlorinated
        Hydrocarbons
Aromatic
Hydrocarbons
                                                                           Phenol
                                                                              A'B'B  1
-------
          CLEAN-UP RESULTS PROM A FORMER GAS WORKS
  Petrol*
Petroleum ether
extract
(total organics)
Polyaromatics
Pollutant
          ABB  2
Total cyanide
-------
                   CLEAN-UP EFFICIENCY  FOR  MERCURY  CONTAMINATED  SOILS
CO
h-1
CD
                     800
                     700
                     600
                     500
           mg  / kg 400

           Hg       30°
           Dry wt basSLQP
                     100
                       0
           Percent
           Cleanup
                     O' Input
                     •  Output
                     100
                              Probe Mr. 1
Probe fir. 2
Prob« Mr J
    ABB
Total
Percent
-------
                                         PARTICLE  SIZE
   100

    90

!c  60

ol  __
^  '°
    50
       Clay
             fine
Silt
 average
                            large
         Gravel
fine.    average    large
                                                                                            Stone
                                                                                   10

                                                                                   20



                                                                                   40

                                                                                   .50



                                                                                   73

                                                                                   50

                                                                                   PO
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-------
                                             Dust removal
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 STEP  1.
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 STEP.. 4.
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 STEP 5.
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  WELLS
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 washing/removal of
 particles 12-60

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-------
 SrEFft
FACT  SHEET
United States
Environmental Protection
Agency
                                                                                                                             November 1990
                      Mobile  System  For Extracting Spilled Hazardous Materials From Soil
  The Risk Reduction Engineering Laboratory, Releases Control Branch at
Edison, NJ, has recently developed a mobile system for extracting spilled
hazardous materials from soils at cleanup sites.

  Landborne spills of hazardous materials that percolate through the soil pose
a serious threat to groundwater.
                 Effective response to such incidents should include the means for removing
               the contaminants and restoring the soil to its original condition. Currently
               practiced techniques, such as excavation with transfer to land fill or flushing
               with water in situ, are beset with difficulties - large land area and volume of
               materials involved. An innovative In Situ Containment/Treatment System has
               been developed to treat contaminated soils.  However, it is not suitable for
               all soils and/or all chemicals.
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                 The mobile treatment system (see illustration) has been designed for water
               extraction of a broad range of hazardous materials from spill-contaminated
               soils. The system will: (1) treat excavated contaminated soils, (2) return the
               treated soil to the site, (3) separate/segregate highly contaminated fines (i.e.,
               clay, silt) from cleanable coarse soils fractions for supplemental treatment
               (i.e., solidification, incineration), and (4) treat volatile organic contaminants
               through use of vapor phase carbon canisters. A prototype system has been
               developed utilizing conventional equipment for screening, size reduction,
               washing, and dewatering of the soils. The washing fluid water may contain
               additives, such as acids, alkalies, detergents, and selected organic solvents
               to enhance soil decontamination. The normal processing rate will be  3.2-m3
               (4-yd3) of contaminated  soil per hour when the soil  particles are primarily
               less than 2-mm in size and up to 14.4m3 (18-yd3) per hour for soil of larger
               average particle size.

                 For further information, contact the Risk Reduction Engineering Laboratory,
               Releases Control  Branch, Edison, NJ. Telephone numbers  are:  (908)
               321-6926 or (FTS) 340-6926.
                               SPKNT CARKON
           PROCESS FLOW SCHEME FOR SOIL WASHER
-------
322
-------
                MOBILE PILOT SCALE SYSTEMS FOR ON-SITE VOLUME
              REDUCTION TESTS ON SOILS, SLUDGES AND SEDIMENTS
LOCATION
  USEPA, RREL, Woodbridge Avenue, Edison, New
Jersey 08837-3679

CONTACT
  Releases Control Branch, Michael Gruenfeld,
CML (908)321-6625, FTS 340-6625.

PURPOSE OF FACILITY
  The various units employed in these systems are
available for use at any  applicable cleanup site,
including Superfund, UST, RCRA or other.
  Volume reduction treatment for soils, sludges and
sediments is receiving increasing interest as a step
in cost-effective treatment trains used for cleanups.
This treatability testing capability consists of two 40
foot semi-trailers fitted with a series  of  volume
reduction related unit processes suitable for particle
size segregation and extraction of contaminants
from solid particles, and one 40 foot semi-trailer set
up as a mobile physical testing laboratory for bench
scale tests and soils-related physical measurements.

CAPABILITY
Wastes for which Facility is Permitted
  As  mobile .systems,  these  facilities  do  not
ordinarily need RCRA permitstoconduct treatability
studies  on Superfund sites. State rules must  be
checked in each case. The systems are designed to
be easily decontaminated, thus any waste can  be
handled. Special considerations would  have to be
given  to highly infectious  wastes  or  radioactive
wastes.
EQUIPMENT AVAILABLE
  The   Unit  Processes  involved  include  dry
screening,  wet  screening  on  a  variable mesh
trommel  screen,   and  various  wet  and  dry
classification  processes. Additionally,  two  pilot
systems are currently under development and will be
added  to the treatability capability: one ultrasonic
system for removal of organics from sands and silts
and one acid/base extraction system for removal of
heavy   metals.  The  Mobile   Physical  Testing
laboratory is equipped with a glovebox and hood,
and has a six-air-change-per-hour HVAC capability.
Additionally, it will be equipped  with glassware for
lab bench scale treatability testing and with wet and
dry screens  characterization.

PUBLIC AVAILABILITY
  These units will be available in the Fall of 1989 on a
regional need and program interest basis. Assuming
each test is  approximately one month in duration,
the facility could be used for a maximum of 10-12
tests per year.

USER FEE
  The cost of a test will be made up of several sub-
elements:  planning,  mobilization/demobilization,
on-site operations  and  report  preparation.
Estimated costs range from approximately $20 K to a
relatively short and simple test conducted in New
Jersey  to over $100 K for extended tests conducted
over 1,000 miles away.
                                              323
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324
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IV

                                                         •
                                        Mobile Soils Washing System
-------
326
-------
                    United States
                    Environmental Protection
                    Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
                    Research and Development
EPA-600/S2-83-100 Dec. 1983
&EPA         Project  Summary
                    Mobile  System for  Extracting
                    Spilled  Hazardous  Materials
                    from  Excavated  Soils
                    Robert Scholz and Joseph Milanowski
                      A technique was evaluated for the
                     scrubbing or cleansing of excavated
                     •oils contaminated  by  spilled  or
                     released hazardous substances.
                     Laboratory tests were conducted with
                     three  separate  pollutants  (phenol,
                     arsenic  trioxide.  and polychlorinated
                     biphenyls [RGB's]) and two soils of sig-
                     nificantly   different  character
                     (sand/gravel/silt/clay  and  organic
                     loam).
                      The tests  show that scrubbing of
                     excavated soil on site is an efficient
                     approach for freeing soils of certain
                     contaminants but that the effectiveness
                     depends on the washing fluid (water +
                     additives) and on the soil  composition
                     and particle-size distribution. Based on
                     the test results, a full-scale, field-use,
                     prototype system  was designed.
                     engineered, fabricated, assembled, and
                     briefly tested under  conditions where
                     large (>2.6 cm) objects were removed
                     by a bar screen. The unit is now ready
                     for field demonstrations.
                       The system includes two major soil
                     scrubbing components: a water-knife
                     stripping and soaking unit  of  novel
                     design for disintegrating the soil fabric
                     (matrix)  and  solubilizing  the
                     contaminant from the larger particles
                     (>2 mm) and an  existing,  but re-
                     engineered, four-stage countercurrent
                     extractor for freeing the contaminants
                     from smaller particles (<2 mm). The
                     processing rate of the system is 2.3 to
                     3.8 mVhr (4 to 5 ydVhr). though the
                     water-knHe  unit (used  alone) can
                     process 11.5 to 13.5 mVhr (15 to 18
                     ydVhr). The complete system requires
                     auxiliary equipment, such as the EPA-
                     ORD  physical/chemical  treatment
                     trailer,  to process the wastewater for
 recycling; under some circumstances,
 provision must be made to confine and
 treat released  gases and  mists.
 Treatment  residues  consist  of
 skimmings from froth flotation,  fine
 particles  discharged  with  the  used
 washing fluids, and spent carbon. The
 principal  limiting  constraint  on  the
 treatability of soils is clay content (high
 weight-percent), since breaking down
 and efficiently treating consolidated
 clays is impractical or not economically
 attractive. Most inorganic compounds.
 almost all water soluble or readily oxi-
 dizable organic chemicals,  and some
 partially miscible-in-water organic* can
 be treated with water or water plus an
 additive.
   During limited laboratory extraction
 tests,  phenol was  very  efficiently
 removed  from  both  organic   and
 inorganic  soils,  whereas  PCB   and
 arsenic clung more tenaciously to the
 soils and were released less readily into
 the washing fluids. The extent to which
 the system has practical, cost-effective
 utility in a particular situation cannot be
 determined until preliminary, bench-
 scale lab work has been performed and
 acceptable limits of residual concentra-
 tions in the washed soil are  adopted.
 Laboratory tests show that soil scrub-
 bing has  the  capability of  vastly
 speeding up the  release of chemicals
 from soils, a process that occurs very
 slowly  under  natural leaching
 conditions.
   Note that this system requires exca-
 vation  of the soil, which  can subse-
 quently be replaced or transported to a
 low-grade landfill. In situ washing of
 contaminated soil, a process in which
 the contaminated area is isolated for
                                  327
-------
 objects, size reduction to maximize soil-
 solvent contact,  extractive treatment,
 separation of contaminated solvent from
 (relatively) decontaminated soil particles,
 and return of the soil (either "as is" or
 after drying) to the excavation.
   Excavation can be readily handled by
 conventional   earthmoving  and
 construction  machinery. Size reduction
 ot soils can be  accomplished with
 various,   commercially  available
 equipment,  including rotary scrubbers,
 log washers, attrition scrubbers, and
 high   intensity  water-knives.  The
 properties of each were considered, and
 the water-knife was chosen as the most
 versatile unit; it was also suitable for both
 disintegrating clay-like  lumps and for
 scrubbing the loosely held contaminant
 from  the  resulting  smaller  (>2 mm)
 components.
   For  the decontamination process to be
 effective with a wide range of  water-
 insoluble and tightly held contaminants
 on small particles (>2 mm), follow-on
 multi-stage extraction was judged to be
 necessary.  The  use of  countercurrent
 extraction   allows  several  stages  of
 extraction  with minimum solvent use.
 Clearly, the final system also requires
 equipment  to separate fines from  the
 solvent, both between extraction  stages
 and   after   the   last  stage. Gravity
 separators,  clarifiers, and  filters were
 generally inappropriate for the planned
 system; hydrocyclones were selected for
 evaluation.
   The  three hazardous  contaminants
 selected for testing were phenol, arsenic
 trioxide, and PCB's. These were chosen
 because of the frequency with which they
 are encountered in spills and the range of
 physical and chemical  characteristics
 they offer. Laboratory tests were carried
 out to assess the  effects of different
 water-based solvents and different pro-
 cessing conditions  on  these   three
 chemicals mixed  with the two soil types
 noted earlier. The results of these studies
 were then used to design the full-scale
 prototype.

 Equipment Evaluation
 Size Reduction and Extract/on
  A series  of tests was conducted with
 the water-knives, first using a local, avail-
 able,   uncontaminated  soil  sample.
 Numerous approaches to exposing the
 soil to the water-knife jets were tried and
 abandoned (refer to the full report). Only
when  the   soil  was contained   in  a
truncated,  cone-shaped,  tilted rotary-
screen drum (2-mm mesh openings) was
the desired lump breaking obtained. The
first tests were performed in an 18-in.
trash basket (top ID = 15 in.; bottom ID =
12 in.) in which  50% of the bottom
sidewall (up to 8 in.) was cut away in four
sections that were overlain with various
mesh  screens.  (The  device  was  re-
engineered for the actual testing.) In the
bench   apparatus,  approximately two-
thirds of the soil was washed out through
the screen  within the  first  2 min of
treatment with 4.5 L/min (1.2 gal/min) of
water at a pressure of 4.9 kg/cm2 (70psi)
and a drum speed of 10 to 20 rpm. Further
experiments indicated that a three step
sequence was needed to achieve the best
decontamination:

   1. Low-pressure wash,

   2. Soaking, followed by stripping, and

   3. Low-pressure fresh-water wash.

Liquid-Solid Separation

   To study the separation  of soil fines
from water,  a full-sized hydrocyclone
(227 L/min) was used  with different
inflow rates (and pressures) and different
concentrations of both soils. Though the
results  of  these  tests  show that  the
hydrocyclone  is  suitable for each soil.
they also indicate that the solids were
better  concentrated  in the  underflow
from the inorganic soil. With both soils,
the  overflow  contained  a small  but
significant amount of fines (0.7% to 3.7%),
which would require additional separation.
Passing  this   overflow   through   the
hydrocyclone in a second treatment was
not notably effective in removing these
fine solids.
   Because the  hydrocyclone was too
large for  routine use in the laboratory
study of contaminant removal from soil,
simply gravity settling in a beaker was
evaluated and found to represent a good
simulation of  the separation achievable
with the hydrocyclone.

Extraction Tests
   Tests were carried out with the three
chemicals (all  three were not used in all
experiments) to establish the following:

   a) probable  loading on a soil column,

   b) distribution on particles of different
     sizes, and

   c) effect of  extraction with different
     sovents on  particles of different
     sizes.
Column Loading Studies
  A  stock solution  of the contaminant
equal in volume to the void space in the
column was added to a 15.2-cm (6.0-in.)
column of  soil (various moistures and
densities) and allowed to drain for 24 hr.
The   contaminant  remaining  in   the
column was calculated on a dry  weight
basis, based on the  amount of fluid that
drained from the column. Modified  gas
chromatographic and atomic absorption
methods  (described more fully  in  the
report) were used. Results obtained with
the three materials are shown in Table 1.
Note the  heavy loading of phenol, which
represents the situation that might exist
shortly after a spillage onto soil.

Distribution Tests
  Different procedures were used with
phenol and with arsenic trioxide to evalu-
ate their distribution  on particles of
different sizes. For phenol, dry soils were
first size-classified with a sonic fraction-
ation device.  Each fraction was then
wetted with a stock solution of phenol.
After 18 hr. the  fractions were rinsed
with water and analyzed. For arsenic, the
soil from the column dosing tests was
dried,  size  fractionated,   and then
analyzed.  High  recoveries  (based on
analyses) were achieved in both cases.
  With phenol, these tests indicated that
approximately 90%  of the contaminant
was  absorbed (or retained interstitially)
on the larger particles (0.6 to 2 mm*) of
the  organic  soil.  These  somewhat
unexpected  results  also appear to be a
consequence of nonuniform distribution
of organics in the different particle-size
fractions. Tests confirmed that the  fine
particles  contained  predominantly
organic degradation products rather than
plant tissues, which remained primarily
with  the  larger  particles.  Such
differences  may make it necessary, in
some  cases,  to  presoak the  soil for
efficient extraction.
  Unexpected results were also obtained
when testing the distribution of phenol on
the  inorganic soil. The relatively  low
adsorption  by the  finer particles was
attributed  to difference*  in  internal
porosity  and  chemical  composition
between the large  and small particles
rather than the proportionately  greater
surface area  (calculated on a  weight
basis) of the fine particles.
  The results  obtained with  arsenic
trioxide on the organic soil were similar to
those obtained with phenol. With the
                                                                                 • Nominal *OM •'• 8***1 '<*
                                                       328
-------
inorganic  soil, however,  the  arsenic
compound  exhibited  the  normally
expected relationship between  particle
size  (i.e., surface  area) and  amount
adsorbed. That is to say, because of the
greater   surface-to-mass  ratio,  more
adsorption occurs per unit weight of fines.
  PCB's were not tested to any  great
extent because of their low solubility and
the hazards  involved in working with
them. Time and funding constraints also
influenced this decision to  curtail PCB
studies.

 Water-Knife Stripping Tests
  Contaminated   soil   samples  were
subjected to 1 min of stripping by the
water knife  to remove particles smaller
than 2 mm. Residual contaminants on the
remaining (larger than 2 mm) particles
were then determined. The results (Table
2) show the value of additional washing
or extraction, at  least for  phenol and
arsenic trioxide.

Chemical Extraction Tests
   Since water is not the optimum extract-
 ant for all contaminants tested, and since
 most  of the contaminants  will   be
 absorbed by and adsorbed on the smaller
 «2  mm) particles, a series of tests with
 the  following aqueous  solutions was
 conducted  to  determine whether
 extraction efficiency could be improved:

  water «• sulfuric acid to pH 1

  water + sodium hydroxide to pH 11

  water + 7.5% sodium bisulfata

  water + 5.0% sodium hypochlorite

  water* 1.0%TWEEN80

  water* 1.0%MYRJ52

  water *• 5.0% methanol

   For the inorganic soils contaminated
with phenol, all extractions were  highly
efficient,  with removals  greater than
87%. Only for the organic soil could the
difference  between  solvents  be
considered significant, with the sodium
 hydroxide   solution  being   the  most
 effective solvent. A portion of  the data
 presented in the report is summarized in
 Table   3.   The   relative  and  actual
 importance  of the residual contaminant
 on the soil  should not  be  ignored, nor
 should the fraction of solvent remaining
 in the  soil (not shown in Table 3). When
 the  residual  level  of contamination  is
Table 1.    Maximum Column Loadings
Contaminant
Phenol
Arsenic trioxide
PCB
Organic Soil
Img/g soil)
453.2
5.0*
25.6
Inorganic Soil
(mg/g soil)
48.3
0.75'
3.0
'As arsenic (As).
Table 2.    Effect of Washing on Large Particles *
Soil
Inorganic



Organic



Test
Time
(min)
IS
30
60
120
IS
30
60
120
Phenol
97.9
98.2
98.8
99.1
60.7
79.2
86.0
91.6
% Removal
x*,o,
28.9
52. 1
42.2
52.1
47.7
55.8
54.0
S9.0
PCB
21.4
5O.O
21.4
28.6




*2 to 12.7 mm
Table 3.   Solvent Extraction: Representative Single-Washing Tests*
Contam-
inant
Phenol


AstOt



PCB



Soil"
1
O

1

0

1

0

Solvent
Water
Water
NaOH (pH 1 1)
Water
HjSOt (pH It
Water
HiSOt (pH 1)
Water
1% Tween SO
Water
1% Tween 80
Initial
Soil Dose
(mg/g dry
soil)
48
452

0.75

5

3

26

%
Removal
98.6
77.8
88.4
42.7
85.3
75.0
85.0
24.6
37.5
48.3
23.8
Supernatant
Concentration
(mg/U
1.190
17.600
20.000
16
32
376
426
72
110
418
366
Residual Soil
Concentration
mg/g
0.68
1O0.4
52.5
0.43
0.11
1.2S
0.7 S
2.66
1.88
132
19.5
 • fxtractant to dry solids  10:1 (w/w).
 " I - inorganic: 0 - organic.

 sufficiently low. the treated soil may no
 longer require  disposal as a hazardous
 material, e.g., in a safe landfill.
   Samples  of  phenol-contaminated
 organic and inorganic soils  were also
 subjected to multiple extractions. These
 tests  demonstrated   that   continued
 removal of phenol did occur, even when
 the extractant was recovered solvent
 (water) from a previous stage and already
 contained   phenol.   Residual  phenol
 concentrations of 30 mg/kg (0.03 mg/g)
of  soil  were  achieved  after  four
countercurrent  extractions  of  the
inorganic soil.


Prototype Design and
Construction
The  process sequence  for  full-scale
treatment (Figure 1) was finalized, based
on  the  laboratory  experiments.  The
sequence includes initial  removal of
oversized chunks P>2.5 cm), water-knife
                                                           329
-------
 scrubbing to deconsolidate the remaining
 soil matrix and to strip any contaminant
 loosely absorbed on the solids(>2 mm)or
 held in the void spaces of the soil, and
 four-stage,   countercurrent   extraction
 coupled  with hydrocyclone  separation
 after each extraction  stage to separate
 the solids (<2 mm) from the liquid. Froth
 flotation is used to give maximum mixing
 of extractant and soil in each stage. The
 overhead extract (mostly sorbent)  from
 the first  stage  extractor hydrocyclone
 contains the highest level of dissolved (or
 dispersed) contaminants and fines. This
 extract must be clarified and then treated
 (possibly with activated carbon) before it
 is recycled.
   Note that: chunks (> 2.5 cm) are not
 normally  processable  in the system
 except for moderate washing  on a bar
 screen*; the 2.5-cm to 2-mm as well as
 the <2-mm fraction, will be used to fill in
 the.excavation; all processing fluids must
 be  appropriately treated. All dust  and
 vapor emissions should be ducted to an
 air cleaner or scrubber before discharge.
   The  basic  system  was  constructed
 according to the design shown in Figure 1.

   The  water-knife  unit  (rotary  drum-
 screen scrubber) consists of a tilt-skip
 loader  and hopper feed from which the
 soil moves into a tillable 19-m (21 -ft) long
 by 1.4-m (4.5-ft) ID cylinder fined with
 end pieces, water-knives, and a rotating
 mechanism (Figures 2. 3, and 4).
   Soil  is  metered  from the  tilt-skip
 reservoir hopper at rates up to 18 ydVhr
 onto a manually washed  bar  screen
 where  >2.5-cm  (1-in.)  chunks  are
 rejected. The solids then pass into the
 tilted drum-screen  scrubber  where  it is
 subjected to first-stage water-knife strip-
 ping, water soaking, and finally second-
 stage water-knife stripping using fresh or
 partially recycled water. The first section
 of the scrubber cylinder is 1.3-m (4-ft)
 long and is fabricated from 2-mm mesh
 (HYCOR   Centra-Shear  screen)   and
 equipped with  internal water-knives.
 Solids then move  into  the  5-m (15 ft)
 soak cylinder that is fined with a baffle
 plate  that has  a 0.5-m (22-in.) center
 opening through which solids pass into a
 0.7-m  (2-ft) long screened, water-knife
 rinse zone.  Fines «2 mm) pass through
 the screens, as does the wash water. The
 coarse particles are voided at the end of
                                  +2 mm Scrubbed Soil
' There ere two bar screens. The toil is noted-reused
 on • 7.5- or 5-cm (3- or 2-in.) upper screen in the
 •kip-hopper from which large or nondisintegrable
 chunks are raked off. Washed chunks that pass the
 upper screens are rejected and removed at the
 second (lower) bar screen «2.6 cm [1 in.]).
Contaminated
    Soil
     u
Feeder
Rough
Screen
\
>
          Oversize
          Non-Soil
          Materials
         and Debris
           ' •  Exhaust
             from Hood
                                                           Skimmings
                                                           to Disposal
            Counter-Current
               Chemical
               Extractor
          -2 mm
                                               Spent
                                               Washing
                                               fluid*
                                                               Scrubbed
                                                                 Soil
 Drying
  Bed
(If Needed)
                                                         Runoff
            Clarifiar
                                       Fitter
                                       Backwash
 j	.  Fines to
J    Disposal
                  Clarified
                  Washing Fluids
                Makeup Water
Washing Fluid ftecycler
                                           I
                                      Spent Carbon
                                           I
Figure  1.    Process flow scheme for soil scrubber.
 Figure 2.    Fully constructed rotary drum screen scrubber.
the drum. The unit can be backflushed M
needed. The screens resist  buildup of
fines (blinding). The actual arrangement
of the water-knives and other details of
construction are given  in the project
report.
           From the water-knife and soaker unit,
        the slurry (<2-mm particles) is pumped to
        the  countercurrent extractor. The four-
        stage  countercurrent extraction  unit
        (Figures 5 and 6) has been modified from
        the  so-called EPA  beach sand froth
                                                             330
-------
                Tilt Skip
                Hopper up to
                Load Metering
                Hopper
                                                           Metering Hopper
                                                            Drum-Screen
                                                            Soil Scrubber
Hand Wash
Large
Stones
figure 3.    Soil loading and metering system (cross sectional side view).
                                                             Initial
                                                          Spray Zone
                                                                         Soil In
                                                                  Inner
                                                                  Cylinder

                                                              Outer Shell
                           A. Drum cross section

                           ,~~ 16 Inches
                                  Battle
                                             Soil Surface
                                                                Inner
                                                                Cylinder
Figure 4.
       Soak Zone
 Channel Formed oy     Screen
 Soil and Drum Wall

                 B. Drum Isometric

Soak zone description.
flotation  unit.* Basically, the washing
chamber  was  partitioned  into  four
sections  (3-ft long X 4-ft wide X 5-ft
deep),  each  of which  has an  aerator
agitator and a hydrocyclone with pumps
and piping. Flow  of solids «2mm) and
fluid is countercurrent with clear water
being introduced at the fourth (discharge)
chamber (Figure 6). The extraction unit
has an on-board  diesel  generator; the
water-knife unit requires external power.
The underflow (solids-rich) slurry from
the fourth hydrocyclone is discharged to a
drying bed.
  To achieve mobility,  the water-knife
unit  is skid-mounted for  transport by
semi-trailer; the countercurrent extractor
is integrally attached to a separate semi-
trailer. Refer to Figures 2 and 5 for details.
Calculations   indicate  that  the  total
system has a throughput range of 2.3 to
3.8 mVhr (3-5  yd'/hr). but that the
water-knife unit alone can process 11.5
to 13.5 mVhr (15 to 18 ydVhr).


Conclusions

  The  following   conclusions  can  be
drawn from the work carried out during
this program  and the knowledge gained
during that effort:

  1.  Spill-contaminated  soils  can  be
    excavated and treated onsite  using
    extraction with water or aqueous
    solutions for many pollutants that
    are frequently encountered in such
    situations.

  2. A system capable of decontamina-
    ting 2.3  to 3.8 mVhr (3-5 ydVhr) of
    soil  has  been  designed  and
    constructed  and it is now available
     for field testing by EPA.

  3. Water-knives function as a compact.
     efficient and economical means or
     achieving effective contact between
     contaminated soil  particles and
     extractant

  4. Countercurrent  extraction  is an
     effective  process   for  removing
     certain   adsorbed   contaminants
     from  soils  and, for the  size  of
     equipment  needed,  hydrocyclones
     are preferred devices for separating
     the extracted solids from  the ex-
     tractant.
 •Girth D. Gumtz. Ractorotion of Beach** ConUmin-
 •tad by Oil. EPA-R2-72-046 (WMhington. D.C.: US
 EPA. 1972).
                                                          331
-------
  5. Laboratory  experiments  demon-
    strate   that   soil  characteristics
    (particle  size,  distribution, organic
    content.  pH, ion-exchange proper-
    ties, etc.) are  important factors in
    the  removal  or  retention  of
    contaminants.

  6. In addition to the actual percentage
    of the contaminant  removed, the
    allowable  level  of  pollutant
    remaining in the soil is an important
    factor   in  determining  when
    adequate  decontamination   has
    been  achieved  since  the   final.
    residual  concentration affects the
    options available for disposal of the
    cleansed solids.


Recommendations


  Based on the observations made during
this investigation,  several suggestions
are offered for future work.

  1. Laboratory screening tests should
    be performed on a wider range of
    typical  compounds  and mixtures
    encountered  in  hazardous
    substance spill and release situa-
    tions to ensure that appropriately
    high levels of decontamination can
    be achieved with this process.

  2. The results of this study apply pri-
    marily to spill situations. Contami-
    nated soils found at waste disposal
    sites   may  exhibit  different
    extraction  characteristics because
    of the extended soil/contaminant
    contact time and of weathering and
    in situ reactions. Studies are needed
    to establish whether and to what
    extent  such  changes  affect the
    decontamination process.

  3. Other  extractant solutions should
    be evaluated to determine whether
    the efficiency of the process can be
    improved without  damaging the
    equipment  or  increasing  the
    hazards  to which the workers are
    exposed.

  4. A wider range of soils should be
    examined  to  determine   what
    changes in the system are practical
    to better cleanse soils with charac-
    teristics  (e.g., greater cohesiveness
    and adsorptive properties of clay-or-
    silt-rich  soils) that  differ  signifi-
    cantly from those of the soils already
    tested.
Figure S.
  Chemical
  Additive
  (If Needed]
             EPA Froth Flotation Systemfbeach cleaner) modified as a countercurrent
             chemical extractor for soil scrubbing.
 Spent
Washing
 Fluid
           Raw
           Feed
                    Chemical
                     Additive
                    (H Needed)
 Chemical
 Additive
(H Needed)
Fresh
Water
Figure 6.
                 Slurry Pump


             Process flow scheme for soil scrubber.
                                                                    Clean
                                                                    Product
  The  full  report  was  submitted  in
fulfillment of Contract No. 68-03-2696 by
Rexnord. Inc., under the sponsorship of
the JU.S.  Environmental  Protection
Agency.
                                                        332
-------
     Robert Scholz and Joseph Milanowski are with Rexnord Inc.. Milwaukee. Wl
       53214
     John E. Brugger is the EPA Project Officer (see below).
     The complete report, entitled  Mobile System for Extracting Spilled Hazardous
       Materials from Excavated Soils." (Order No. PB 84-123 637; Cost: 511.50.
       subject to change) will be available only from:
             National Technical Information Service
             5285 Port Royal Road
             Springfield. VA 22161
             Telephone: 703-487-4650
     The EPA Project Officer can be contacted at:
             Municipal Environmental Research Laboratory—Cincinnati
             U.S. Environmental Protection Agency
             Edison. NJ 08837
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
  BULK RATE
 U.S. POSTAGE
    PAID
Cincinnati. Ohio
Permit No. G35
Official Business
Penalty for Private Use $300
                                                                                   ft U.S. GOVERNMENT PRINTING OFFICE: 1984.756-102/819
                                                            333
-------
-------
FIELD APPLICATION OF PILOT SCALE
          SOILS WASHING SYSTEM
               -Lakehurst Naval Air Station, New Jersey-


                            by
                         James Nash
                      Roy F. Weston, Inc.

                      Contract 68-03-3450

                    Work Assignment 1-87215
                        Project Officer:
                     Richard P. Traver, P.E.
               Program Manager/Soils Treatment Team
                     Releases Control Branch
                Risk Reduction Engineering Laboratory
                U.S. Environmental Protection Agency
                       Edison, NJ  08837
           RISK REDUCTION ENGINEERING LABORATORY
             OFFICE OF RESEARCH AND DEVELOPMENT
            U.S. ENVIRONMENTAL PROTECTION AGENCY
                   CINCINNATI, OHIO 45268
                           335
-------
                                      CONTENTS
                                                                                                                         ABSTRACT
uo
OJ
Abstract	 ii
Figures	ill
Tables	ill
Acknowledgements	iv
1.   Introduction	1
2.   Conclusions	2
3.   Recomnendations	1
4.   Soil Hashing	4
          Contamination and Particle Size	4
          Separation Techniques	5
5.   The Pilot Drum Screen Hasher	8
          Design	8
          Performance	8
6.   Soil Hashing at NAEC Lakehurst	11
          Bench Tests	11
          Pilot Testing	11
7.   QA Discussion	IS
8.   Results and Discussion	16
Appendices
  A. Pilot Drum Screen Hasher, Plans
  B. Analytical Data
     Volume  reduction pretreatment  and  feedstock preparation  of
contaminated  soil by soil  washing will  be  a viable  alternative
technology   to   allow  landfilling  under  the  Land   Disposal
Restriction  regulations  to take effect  November 1988.   To  allow
for  economical field evaluation treatability studies,  the  EPA-
Releases Control  Branch has fabricated a  pilot drum screen washer
capable of operating at  up to 100 pounds of soil per hour.  The
unit is constructed  of 316 stainless steel,  requires 100 VAC, 20
AMP  electrical  service  and  weighs approximately  750  pounds.
Hater requirements are up to  8-gallons  per  minute at 100-pounds
per square inch pressure.  Successful operation for sixteen hours
was  performed at 2-gallons  per minute.   A field trial  of the
unit, using a biodegradable grease cutting additive  added at one
pound per ton of soil, achieved a 99% reduction in oil and grease
for  a  petroleum  hydrocarbon  contaminated  soil  bringing  the
cleaned soil   fractions  below the RCRA  hazardous waste action
level.   The drum  screen washer is  a  key  component of a treatment
process.   Feed   stock preparation,   dewatering  of  contaminated
fines  and  post  washing  separation  techniques  are  added  as
required.
-------
(JJ
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                                        FIGURES
            NUMBER
              1  Basic Components of a Soil
                Hashing Process
              2  Basic Components of the
                Pilot Drum Screen Hasher
              3  Pilot Soil Hashing Process at
                NAEC, Lakehurst July-August 1988
NUMBER
  1  Example of Distribution
     of Contamination
  2  Liquid Solid Separating
     Techniques
  3  Soil  Feed  Rate  - Freehold
     Series Soil
  4  Hash  Fluid Flow Rates -
     Tap Hater
  S  Lakehurst, NAEC Soil
     Hashing Data
  6  Replicate  Data  on
     Collocated Saaples
                                         TABLES
 EASE.

  7

  9

 13



 PAGE

 5

 6

10

10

14

13
                          ACKNOWLEDGEMENTS
      The  cooperation  of the Environmental  Engineering Office of
 the  Naval Air  Engineering  Center,  Lakehurst,  New  Jersey,  most
 particularly Ms. Lucy   Bottemly,  made this field study possible.
 In helping to  arrange  for this field study  the  author wishes to
 thank Mr. Mike Lukas  of  the  Navy Facilitties Northern Division
 and Mr.  Glenn Hilmar,  EPA Region II RPM for NAEC  Lakehurst.   Tony
 Rubo,  of Enviresponse  Inc. provided the mechanical design of the
 pilot  unit used  in this  study and  Jerry Cotter, of G. Cotter
 Enterprises   fabricated  the   unit,  along  the   way  making
 improvements  as necessary.  Dave  Knapp  of  Enviresponse greatly
assisted  in  the  field  work  and  Richard  P.  Traver  of  the  EPA
Releases Control  Branch  provided technical guidance  and support
for this effort.
-------
00
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OO
                            SECTION 1
                          INTRODUCTION
     The process  of  "soil  washing" to  remove  or  decrease  the
concentration  of  contamination  on  soil has  been  an  area  of
intense study by  the  EPA,  Risk Reduction Engineering  Laboratory
for eight years.  The outgrowth of that work  is the  EPA  Mobile
Soils Washing System.  Mounted on  three trailers, ranging  40 and
50 feet in length, this system is  capable of washing  up to  12,000
pounds of soil  per  hour.   This report describes a smaller field
unit.   Constructed  as part  of this work  assignment,  the  Pilot
Drum Screen Washer is intended to  provide RPMs  and other decision
makers with a  relatively  low cost apparatus to  rapidly  evaluate
soil washing  technology  feasibility at  individual  waste  sites.
The  unit  is  also   very   suitable  for  use   at a  centralized
treatability lab.

     Traditional  laboratory  or  pilot  scale   soil   treatability
studies have typically relied upon random  sampling of  the total
hazardous  waste  site soil   and  compositing  both   surface  and
shallow excavated grades  into a  single  sample.   The  composited
sample is then  returned to the lab, and from  this  grab an even
smaller grab is taken to perform the treatability evaluation.

     The 100 pound  per hour f/hr  Pilot Drum Screen  Hasher,  just
by it* shear processing capacity,   is capable of  treating several
tons of soil  over a short two week period.   This approach will
provide  a  tremendously  useful engineering  design  database  by
evaluating not only varying concentrations of contaminants  across
a waste  site,  but also varying soil characteristics which will
also typically occur in the field.
                       SECTION 2
                      CONCLUSIONS

The principle of soil washing and dividing  the soil-wash  mix
according to particle size is proven  in  this work to  yield a
99% reduction in oil and grease content.  The soil washed in
this field study was approximately 90% by weight  in the
0.25-nm to 2-mn  size range.   Using the  biodegradable grease
cutter Citrikleen'"', excess  petroleum hydrocarbons and
solids finer than 0.25-mm 90% of  the soil achieved 90%
reduction.

Sludge produced  from this process can be dewatered to
achieve a 40-45% solids filter cake.

The pilot drum  screen washer is  a  field worthy  pilot  unit.
The unit  processed  soil over a two  week period  for  as ouch
as  ten  hours at a  stretch.   The  only  system  problem  was
nozzles  plugging with  imperfectly  filtered  pond supplied
wash water.  These were unplugged as they occurred.

For this  field  study, wash  waste water was very  effectively
treated.  Using a continuous belt filter press recycle  water
was  provided that   surpassed  the  initial  quality  of  the
original pond supplied wash water.
-------
   SECTION 3
RECOMMENDATIONS
1.    Install  upflow  separators or  wet classifiers  beneath the
     Pilot Drum Screen Washer to remove the waste water from the
     soil particles.   This will Improve the quality of clean soil
     fractions.

2.    Also include an auger classifier to discharge the particles
     from the bottom of the upflow separator.  Recommendations 1
     and 2 basically  accomplish the  separating  function  of the
     existing Countercurrent Extraction Unit  used in the Mobile
     Soils Washing System.   Although the residence time is longer
     in the CCU,  the  work  done here implies that residence time
     may not  be necessary.

3.    A dedicated trailer with an auger or bucket  conveyor to feed
     the pilot  unit  and auxiliary equipment  to  handle the wash
     and waste  water  should  be designed and fabricated to allow
     for rapid  and effective  field  treatability  studies.  Actual
     waste water treatment would best be dealt with  by selecting
     processes on case-by-case basis.

4.   Bench scale  work conducted prior to  this  field study made
     use  of  120°P wash  water that  resulted  in  a 100-105°P mix
     with the soil.  The O ( G levels  achieved in that work were
     lover than reported here.    Provisions  should  be  made  to
     easily heat the wash fluid to enhance  contaminant removal.

S.   Incineration techniques should be investigated to dispose  of
     the high organic (low ash) filter cake sludge.
                            SECTION 4
                           SOIL WASHING

CONTAMINATION AND PARTICLE SIZE
     Measured contamination on  soil   is  greater  for  finer  clay
silt and  colloidal  soil particles  than  for  coarse.   The  reason
is,  for  a  given weight,   fine  particles  have  greater exposed
surface area and  the  apparent  preference of many contaminants  to
adsorb  to particle  surfaces.1   In studies conducted  on various
soils,  ranging in particle size distributions from rocks to clay,
hydrophobic contaminants have  consistently been found at greater
concentrations  in the  finer  fraction.    Even in  the case  of
hydrophilic contaminants,  aggregates of the finer particles,  hold
the  contaminant by  capillarity.   In addition  to the  greater
surface areas clay exhibits high cation exchange capacities which
will attract the contamination.
                                                                The first step  (or steps)  in soil  washing is  to  separate the
                                                           soil according to a  particle size threshold.   A common  threshold
                                                           is  two  millimeters   (2-mn)  above  which  is  considered  gravel,
                                                           cobble,  rocks and boulders;  below  which  is sand,  silts,  and
                                                           clays.   The  most  concentrated  contamination on a  per  weight
                                                           basis,  is  in the  silts  and  clays.    That  threshold  is  0.6
                                                           millimeters and  less.   In  general,  soil  washing separates  the
                                                           bulk soil  into  three size categories greater than 2-mm,  2-mm to
                                                           0.06-mm, and  less than 0.06-am.  The  less than 0.06-mn  includes
                                                           solubilized and emulsified contaminants.

                                                                In  many  instances  the  volume of  soil requiring  costly
                                                           treatment or landfllling can be reduced by soil washing.
                                                                1This is not to ignore the fact that EPA accepted analytical
                                                           extraction  techniques  are   less   likely  to  recover  absorbed
                                                           contaminants therefore  amplifying  the notion  that contamination
                                                           is a surface phenomena.
-------
   and  results  in a  waste water that may  need treatment prior  to
   recycling or disposal.
        The liquid-solid  separating  techniques  that can be used  in
   soil washing include:


               TABLE  2  LIQUID-SOLID SEPARATING TECHNIQUES
CO
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SEPARATION
TECHNIQUES

Grizzly
Screens
Trommels
Classifiers
Settlers
Cyclones
Centrifuges
Filters
PARTICLE
APPLICATION

Debris
Coarse particles
Coarse particles
Medium
Medium
Fine
Fine
Fin*
        Particle size  and density  are  the principal  criteria for
   selecting a  separating  technique.  The EPA Mobile Soils Washing
   System  (MSWS)   uses  trommels   (drum  screen),  cyclones,  and  a
   filter.  The pilot  drum screen  washer  (POSH),  is a trommel.  In
   the  field  treatability study at Naval Air  Engineering Center,
   Lakehurst,   New  Jersey  the  PDSH  was  part  of  a process  that
   included an upflow settler,  settler, and filter.
                                                                     A typical  poorly  graded soil  could have  the  following particle
                                                                     size distribution: >2-ma,  5%;  2-nun to  0.06-mn,  80%;  <2-mo,  15%.

                                                                     This  is  basically  a sand.    Past oil and  grease  analyses of
                                                                     contaminated sand as well  as  the work  reported  in  Section 6 has
                                                                     resulted  in values like  the ones in Table 1.
                                                                                               TABLE 1 EXAMPLE OF DISTRIBUTION OF CONTAMINATION
                                                                                                                                         CONTAMINANT
                                                                                                                                           *  OF
                                                                                                                                           TOTAL
                                                                    Eighty-five percent of  the total  is  holding one percent  of the
                                                                    contamination.   More  importantly 99 percent of the contaminant is
                                                                    on  IS  percent of the sand.


                                                                    SEPARATION  TECHNIQUES



                                                                        Soil washing is  the us* of mechanical and/or chemical  means
                                                                    to  disperse contaminated soil and  separate the contaminant  with

                                                                    as  little  soil  as possible.   A  basic schematic of  a nine  step

                                                                    soil washing process is  shown  in Figure 1.   The beginning of  the

                                                                   separation  process actually begins  with  Step 0 where rocks  and

                                                                   boulders,  trash  and   debris  are  selectively  removed.    After

                                                                   transportation to the  soil  washer,  the actual process begins by

                                                                   dispersing  the   finer  particles  and  the  contaminant from   the

                                                                   coarser soil.  Once the  component parts  are  liberated from each
                                                                   other  in  some  wash fluid,  they  can  be  separated by one  or a
                                                                   combination  of ways.   The  removal  of the wash fluid (and  any

                                                                   rinse fluids) from the solid particles  is  the  final  separation
-------
                              SECTION 5
                      PILOT DRUM SCREEN  WASHER
       The EPA-HSWS,  although a  12,000 f/hr prototype seal* soil
  washing  aystea,   is  quit*  costly  to  transport  and  operate.
  Concerns over  the  expense  of  using  it  at  a  site  without  an
  interim scale above  lab-bench  led to the  fabrication of a pilot
  druo screen  washer.    Ancillary pilot scale  treatment additions
  are planned to  make complete pilot soil washing system.

  DESIGN

       The POSH consists of a variable rate dry feeder and rotating
^creen-drua-screen combination.    Soil  deposited inside the first
'-'cylindrical screen is  dispersed by the tumbling action and spray
  froa wash  nozzles inside the screen.   Particle*  less than 2-mn
  pass through the  screen and  exit  the  POSH through the first sump
  drain.    Particles  larger   than  2-ma  pass  into  a   solid  wall
  cylindrical drua  where the  tumbling  action  continues.   Exiting
  the drua,  onto a  second 2-ma cylindrical  screen,  particles less
  than 2-«a  released from aggregates in the drua pass  through the
  screen.  Dispersed material froa the second screen exit the  PDSW
  through the second sump drain.    Particles larger  than 2-ma exit
  through the third  sump drain.   The basic  components are shown in
  Figure 2.  More details are in Appendix A.

  PERFORMANCE

       The following processing rates for soil  using the PDSW were
  measured using  the soil characterized in the graphs in Appendix B
  (B-l and B-2).
SECONDARY
SEPARATION
            1
COURSE
2— J™ ,
^ 1




                                    1RANSPORT
                                     (clean)
                                                                                                 Figure 1. Basic oor|joncnts of a soil washing process
-------
           TABLE 3. SOIL FEED RATE - FREEHOLD SERIES  SOIL
CONTROLLER
SETTING
100
300
500
750
999
LB/KR
4
11
20
36
56
FEED RATE
FT3/hr
.05
.13
.24
.42
.65
           TABLE 4. WASH FLUID FLOW RATES - TAP HATER
uo

i\5  NOZZLE
    PRESSURE
     (PSI)
      HASH  FLUID
    FLQH      GAL/HIM
(FIRST HASH)  (SECOND HASH
  (1)
BACKWASH
  (2)
BACKWASH
                    TOTAL
    10
    20
    40
    60
    100
    .6
    .8
   1.3
   1.6
   2.2
.6
.9
1.4
1.7
2.4
.56
.85
1.3
1.6
2.2
.3
.5
.8
.9
1.3
2.1
3.1
4.8
5.8
8.0
                                                                                                            FEED
                                             DOUBLE  SCREW  L«acWAa<
                                             AUGER FEED    ftlNFUT
                                                                                      SCMEEN
                                                                                               AUGER FEED
                                                                                                  OU1FOT

1 /
r
/""J

i
1
                                                                                                                                                    MPUT
                                                                                                                      ••  ,   ••yx
                                                                                                                       -LI     IX
                                                                                                                           <2-yy
                                                                                                                                 <2-MU
                                                                                                                                                MUM SCREEN
                                                                                                                                                /-BELT (MM
                                                                                                                                   DRUM
                                                                                                                                 ftOTADON
                                                                                                                                 COM1ML
                                                                                                                                                    1£C
                                                                                                                                                 AOJUSTUEM1
                                                                                             Figure 2.  Basic ccnponents of the PILOT DKJM SCFOH HASHER
-------
                                SECTION 6
                     FUNCTIONAL SHAKEDOWN  OF THE PDSW

         The  PDSW  was  used  at the  Naval  Air Engineering  Center,
    Lakehurst,  New  Jersey between  July 25  and  August  12,  1988.   The
    primary  goals were twofold.   First  to work the  new  unit under
    field  conditions  and  second   to  provide  useful data  to  the
    Environmental Engineers  at NAEC that would assist then in their
    remedial planning for an actual superfund disignated site.
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     The EPA  -  Region II Superfund  Office,  the Navy's  Northern
Division   Engineering  Facilities   Command  and   the  NAEC
Environmental Engineers,  responded to a request by  EPA'3  Releases
Control  Branch,  to  evaluate  soil   washing  of  a  hydrocarbon
contaminated  site  at Lakehurst,  by  suggesting  eleven  sites.
After   a  preliminary   sampling  survey  and  lab   study  of
contaminant/soil  characteristics,  two sites  were   identified by
the  EPA-Releases  Control  Branch.   The  preliminary  laboratory
characterization  report  of  soil  from  these two sites  is in
Appendix B (B-5 ff).
     BENCH TESTS

         In  the  lab characterization  it  was discovered that  sot  of
     the  soil could  have its  oil  and grease  content lowered by  an
     order of magnitude.   For soil from the  "Blimp Crash Site",  this
     resulted in  a  reduction from RCRA hazardous at 3.6%  to RCRA non-
     hazardous at 350 to  400 mg/kg.
     PILOT TESTING

         Based  on the  lab characterization  study the  soil  washing
     process  at  NAEC  was planned to require complete recycling of the
     wash water.   The site selected,  the Blimp Crash Site, was remote
     with  no available  utilities;  therefore,  all electrical,  pumping
and pneumatic services had to be supplied by portable units.  The
diagram in Figure 3 shows all the  key components in the process.
As discussed  in  Section  4,  the PDSW performs  only part  of the
soil washing process.   The  rest of the process  was assembled to
yield  the  following  particle  size  splits:  greater than 2-mm,
between  2  and  0.25-mm  and  less  than  0.25-raa  with   the waste
water.

     The resultant acidic waste water was a  stable oil in water
emulsion that could be broken by an 800-ppn lime addition.  This
brought  the  pH   to  8.5-9.9.    Because  the  wash  water  also
contained  fine  soil   particles the  broken  emulsion  formed  a
precipitated sludge.   The initial treatment approach was to use a
clarifier to obtain the recycle water.

     A  Mega   Sludge   continuous  belt   filter   press   made  by
Consolidated Sludge Company  was added to the process  during the
second week when  it became obvious  that  the small clarifier could
not keep pace with the water requirements (See Appendix C).  with
the addition  of  the  belt filter  press,  the clarifier became a
sludge thickener  enhanced by additions of anionic electrolyte and
polymer floe aid.  The analyses of  the three product streams with
the PDSW operating  at 100 pounds  per hour agreed  veil with the
lab characterization.
                                                                                    In addition to the soil used in the lab study a coarser soil
                                                                                found  at the  middle  of  the site  at one  foot below  grade was
                                                                                screened  in the  pilot  study.    Table 5  presents  the analyses
                                                                                results for both soils  including  the  process conditions.
-------
                     TABLE 5 -  LAKEHURST,  NAEC SOIL WASHING DATA
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.fc
3.
4.
5.
6.

7.
 DESCRIPTION

 Soil Feed Rat*
    Initial oil t grease
    0.25-2-ma oil t grease
 Wa»h Hater Rate

 Wash Water pH
 Wash Water Total Solids
 Sludge, settled total  solids
 Belt  Filter Press Cafce
  total solids
Belt  Filter Press Cafce
  Ash content
Belt  Filter Press
  suspended solids
                                                   QUANTITY.
                                              (4
   50 - 100 pounds/hr
   38,000 mg/kg
   375 no/kg
   1-2 gal/Bin
.5 liters/pound of soil)
   4.7
   2.97%
  15.5%

   47%

   30%

   20  mg/liter
                                                                                                          Numbers  in  circles
                                                                                                          refer  to Table 5.

SAMPLE

2ND I
SCHEENI




WQCH
(B


i
BLEND

|*ASHmOl
ORUU


1ST
SCMEEN


fTi
SOIL ]
FEED |
                                                                                                Figure 3. Pilot soil washing process at tiAGC, Lakehurat July- Aug 1988
-------
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                                      SECTION 7

                                    QA DISCUSSION

               This  report is submitted  as  a Level  4.   The  data  that is
           reported,  based on replicate analyses of  collocated samples, is
           consistent.  Table  6 is a listing of replicate analyses.
                     TABLE 6.  REPLICATE DATA ON COLLOCATED SAMPLES
SOIL,  OIL 4 GREASE
     Contaminated


     Hashed

BELT PRESS CAKE
     Solids

     Ash


RECYCLE HATER
     Suspended Solids
42,000 mg/kg
35,500
36,000
   400 ag/lcg
   350
                                              48%
                                              46%
                                              28%  Dry  Basis
                                              32
                                              31
                                              25 mg/liter
                                              20
                                                                                                           SECTION 8
                                                                                                     RESULTS  AND DISCUSSION

                                                                                    The  task goal  of  fabricating  and  determining  performance
                                                                               characteristics  for  the PDSW was  accomplished with the bonus  of
                                                                               using  the unit at a  remote contaminated site.   The  POSH,  being
                                                                               only  part  of  a   soil  washing  system,   required   additional
                                                                               equipment.  Both pre and post drua screen operations were  carried
                                                                               out  to best emulate the EPA Mobile Soils Hasher as was possible
                                                                               with  equipment   available.     A  major  observation  for the
                                                                               improvement of the process behavior during  the Lakehurst exercise
                                                                               would  be  the  inclusion  of an  upflow  settling tank and  auger
                                                                               classifier in the soil washing process.
     The PDSH performed well in the  field.   As a matter of fact,
at  up to  100 pounds  per hour  of  contaminated soil,  the soil
feeder out performed the  rates measured using the drier Freehold
Series soil.   Blinding of the screens  did occur but  not  to the
extent anticipated.   Only twice was special backwashing required.
And with  the Blimp  Crash Site soil  very low nozzle  flow rates
were attainable thus reducing the burden on the recycle process.
-------
                                                                        APPENDIX A
                                                                     ACRISON FEED HOPPER
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                                          APPENDIX B

                                             DATA
* Soil Characteristic  Curves  for Soil used to calibrate feed
  rates


* Cltrikleen    data  sheet


* Preliminary lab study
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• C«rboniiM oib and fnmi an ««ilv ftri>o>«a from tt+nti. trarwniMiont.
Ttoton. houtln«B and mtut p*m «>itti Cltriktovn M w*n. foam . a»w»r» or dip
JPOliCMiaAt. Watw rinMO MrfaCH V* dMn.

• In warn traatmant ptarta, Otrlkla«n n uMd for ctoarttof, o)«f/awr«f and
daadorixbtf lift tuoom. w«i ««anatona or o>t local
for furtntf information.
                                                                                                                                           Clulklaan it a biodaojadaDM •»»*-*<**»•. naavv dutv
                                                                                                                                           'ormutatad with an or«an« nonotirowum nvdfocaroon tolvam and a
                                                                                                                                           camponant aurfa«ant-«mutaifl«r tvitwn to m**M •upanor ctaanmf
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                                                                                                                                           fn CltrlklavA aiiovt ditpotM afttf *o*i ^Maaa into Miu'anoniv
                                                                                                                                               i trtitmant piano.
                                                                                                                                           Uwd in coneantrand form or at ••now* wanr dliwtlon fata*. Citrihtaan *iii
                                                                                                                                           rapidlv panattata and lift it>a «x)««t «anoja of patnwawm. animal and vaajtjD*
                                                                                                                                           basad oita. fan and araaaai. »fi«h am tttan aawhr r*ma»ad by wataf nnunf
                                                                                                                                           Tha oilv contaminant! in vtae Citrihlaan totutiorM. lah in a tail  tar* or
                                                                                                                                           hoMtnf pond afttt titaninc. «nil iw to ma  tuMac* and Moaran.  Thi, wi
                                                                                                                                           may M r»mo»ad bv top Mimmmaj  The famamtnf oonom lava* it clean.
                                                                                                                                           Wodafradabl*. rvutabM Uouid ctaarunf to*ution whicfi can o* fluahcd to ma
                                                                                                                                           tawar it no Ion
                                                                                                                       PENETONE CORPORATION  • A Subt^iary of Wttt Chtm«i Products. Inc.
                                                                                                                       GENERAL OFFICES: 74 HUOSON AVENUE. TENAFLY. NEW JERSEY 07670 • I20t| S67-3000
                                                                                                                       OTHER LOCATIONS IN PRINCIPAL CITIES
                                                                                                                                            B-3
-------
                 CITRIKLEEN*
                 A BIODEGRADABLE. WATER SOLUBLE SOLVENT CLEANER AND DEOREASER
                     PROPERTIES:
OH Uoncmtritst.

'IMA *OM»I leoAo«tf«tti

      11 1 0am *«»f,

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-------
                                                                                                                 Contents
(JO
Ul
o
     Although the  information  described  in  this report has been
funded  wholly or  in part  by the United  States  Environmental
Protection Agency under Contract No.  68-03-3450 to Roy P. Heston
Incorporated, it has not bean  subject to the Agency's review and
does not necessarily reflect the views of the Agency  and no offi-
cial endorsement  should be  inferred.
Conclusions	1
Recommendations	1
Background	1
Sampling	4
Soil Size Distribution	8
Contaminant
  Concentrations	11
  Characteristics	.. .11
Soil washability	14
References	17
FIGURES
Figure 1  US EPA Mobile Soils Hashing System	3
Figure 2  Site map of the "Blimp Crash Site*  (Site II)	6
Figure 3  Photograph of part of Sit* II	6
Figure 4  Site map of the Refu«ler Repair Shop, Building 345
           (Site *33)	7
Figure 5  Photograph of the Site 133 area, Building 345 at
          left center of picture	7
Figure 6  Photograph of seeping oil at Site II	10
Figure 7  Trace from infrared scan Site II	12
Figure 8  Trace from infrared scan Site 133	13
Figure 9  Lab soil washing results for Site II	15
Figure 10 Lab soil washing results for Site 133	16
TABLE
Table 1   Soil Particle Sice Distribution for
          Two Soil Samples	9
-------
CONCLUSIONS

     Specifying 2  mm as  the  separation diameter has, in the past,
served as  a  criteria to analyze contaminated soil  and  evaluate
the effectiveness  of soil washing on-soil greater and less than 2
mm.   The  NAEC Sites  II and 133 soils do  not  have significant
quantities >2-mm.    More suitable separation diameter  is  0.25  mm
which is the opening in  a  160-mesh screen.

     The use of a  surfactant to  enhance soil washing is effective
on the  sample  from  the  blimp crash  site,  but  not measurably ef-
fective  (maybe even counter effective)  on  the  sample  from the
refueler  repair shop.   Regardless  of  whether  surfactant is used
on the  soil from the refueler repair  shop,  soil washing was
demonstrated to be effective at  both sites.

RECOMMENDATIONS

      Continue  with  the planned on-site pilot treatment study.  If
only  one  sit*  can be dealt with it should be Site  II.   If time
allows, both  sites  have a  good  prospect  of benefiting from soil
washing as part of  a treatment system.

BACKGROUND
As part of  the  Navy  Assessment  and Control of Installation
                                                                      Pollutants  (NACIP),  44  potentially contaminated  sites at  Naval
                                                                      Air Engineering Center (NAEC),  Lakehurst  have been  identified  and
                                                                      verified.   Of these  sites a number  of  them involve soil con-
                                                                      taminated with petroleum based material.   The  U.S. EPA'a Office
                                                                      of Research and Development, as part of  its mission to stimulate
                                                                      the use of  emerging technologies,  wishes to demonstrate the  ef-
                                                                      ficiency of Soil Hashing  at one site at NAEC.

                                                                           Soil Washing  is  one of  the  Alternative  Technologies  advo-
                                                                      cated by the  US EPA for use at RCRA/CERCLA sites  to reduce  the
                                                                      quantity and  impact of contaminants in soil.   Under contract to
                                                                      the US EPA a number of engineering  and  consulting firms built  the
                                                                      Mobile Soils  Hashing  System.   Shown  schematically in Figure 1,
                                                                      the MSHS  represents  the basic requirements  for  a system that
                                                                      tumbles  and  separates   contaminated  soil into  particle  size
                                                                      categories  that   are appropriate for  subsequent  "ultimate
                                                                      disposal*.
                                                                           This preliminary  laboratory  characterization  of  soil  from
                                                                      two of the sites at  NAEC is presented to the US EPA  and the US
                                                                      Navy prior to conducting an on-aite  demonstration  of  Soil Hash-
                                                                      ing.  The two  sites were  selected based on appropriateness of the
                                                                      technology as it now  stands,  and non-interference with  NAEC
                                                                      operations.
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SAMPLING

     Site II,  the 'Blimp Crash Site* and Site 133, the  "Refueler
Repair Shop,  Building 345*,  were  selected as  good  candidate  sites
for demonstrating soil washing.   Histories and analytical data on
each site were supplied by the EPA Region  II and  NAEC's Environ-
mental staff.
     •The crash of a blimp in 1931 resulted  in the spill of
     approximately 1,000 gallons  of  fuel and  hydraulic  fluid
     over a 20 ft. by 20 ft.  area (Figures  243).  At the
     time of cleanup operations in 1981, the site also  con-
     tained  the  remains of a vehicle and  five  55-gallon
     drums, whose compressed appearance  suggested that  they
     had been dropped  from  some  height.   The site contained
     a rich, wet, black material on the  ground, adjacent to
     the five compressed drums.
     Site  33  is a dry  well located on the  north side of
     Building 345 (Figures 4 4  5),  in close proximity  to  the
     old channel of  the  Ridgeway  Branch.   The building  was
     constructed in  1959  and has been used since  that date.
     Present occupants of the refueler repair shop are con-
     tractors who repair Navy refueler trucks.  The building
     has  a deck drain  leading  to  the dry well.   It  was
     reported that waste solvents,  oils,  and lubricants were
     poured into  the deck drain which  flowed Into the  dry
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     well.   There were no estimate* of the quantity of waste
     lubricant* poured into the dry well.*1

     According  to  analytical  data  obtained on previously  sampled
surface soil,  the blimp crash site has a  pH of 4.1 and  a total
petroleum hydrocarbon content of  54,000   milligrams/kilogram of
soil (rag/kg).  The soil north of Building  345 has a pH of  5.1 and
a total  petroleum hydrocarbon  content  between  1500 and 3400
mg/kg.
     Sample* for  this preliminary  characterization  were  taken
from a single square  foot  area  at  each site.   The sample  taker
purposely took  samples  exhibiting  the  greatest  staining,   (see
Figures 2(4).   The  emphasis of this  study is Soil  Hashing  and
not the cost/benefit  relationship as applied to these  sites.   The
proposed field demonstration and associated sampling will provide
information  to estimate a cost.
                                                                                                          FIRE  WATER  POND
WETLANDS   \
                                                                          Figure 2 Site  M«p  of the "Blimp Crash Site" (Site fl)
                                                                          Figure 3 Photograph of pert of Site II
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flgur. k  Sit.  ««F  of  tU.  R.fu.l.r R.p.lr Shop, Building 3k5 (Sit.
»33)
 Plgur. 5 Photogr.ph  of  th.  Sit. *33 «r.«. Building 3H
 e.nt.r.  Th. dry  v.ll  1*  forward of th. building.
                                                       «t l.ft
SOIL SIZE DISTRIBUTION

     In previous  laboratory  and pilot evaluation*  of soil wash-
ing,2'3 five  broad particle  size  ranges have been specified to
group  soil  particles  for subsequent chemical  analysis  to deter-
mine contamination levels.  These size ranges are:

     o    25 mm and larger - cobble
     o    2 - 25 mm - gravel
     o    0.2S - 2 mm - sand
     o    0.074 - 0.2S mm - fine sand
     o    leas than 0.074 mm - silts and clay

This study  considers only  three  size ranges.   The ranges and the
quantity of soil  (with  contamination)  for each  sample  is listed
in Table 1.
                                                                                          The samples that were  taken do not represent an  average  of
                                                                                     their respective sites.  The  Blimp Crash Site sample  included a
                                                                                     significant quantity of  a  severely stained surface deposit.   It
                                                                                     could have been a  lichen type growth that had absorbed  the  con-
                                                                                     taminant and  subsequently  died,  or just  a  layer of  wind  blown
                                                                                     fine particles,  pollen  and  seeds that came  to rest on the viscous
                                                                                     oily contamination.  Whichever the case, subsurface samples  would
                                                                                     not likely have  this fragile,  low density material to deal with.
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     TABLE  1.   SOIL  PARTICLE SIZE DISTRIBUTIONS FOR TWO SOIL SAMPLES *
              (DRY BASIS)
                                       Sample
                             Site II             Site 133
     Size Range              215-1-1             215-1-33
     > 2 nan
     0.25 - 2  mm
     <0.25 mm
                          7.8
                         74.6
                         17.6
26.4
50.7
22.9
     • These samples were selected from the highest contaminated soil
     at each site.   Therefore  these  values represent neither Site II
     nor Site 133.
OJ
ui
ui
     The condition of the  contamination  in the subsurface is
revealed by  free oil  seeping  to the surface of the water table.
In a 1981 attempt to remove  the  contaminated soil  from Site II, a
pond was created.  During this present sampling, droplets of oil
were observed coming from the bottom of the pond adjacent to the
soil sample location.  (See Figure 6).
                                                                                                            Figure 6 Seeping oil at Site II
                                                                                                The  sample  taken  from Site  33 contained  gravel  and cobble
                                                                                           with  distinct  irregular edges  not characteristic  of  the smooth
                                                                                           rounded stones of the area.  This material, being part of a road-
                                                                                           way, is likely not characteristic  of  the  subsurface.   A fragment
                                                                                           of concrete  50  x 75 mm  was part  of  the  sample, but  not at all
                                                                                           considered in the size  distribution.
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                          CONTAMINANT

Concentrations

     By chloroform extraction,  the measured oil and  grease  for
these two samples are 35000 mg/kg and 4800 mg/kg for Sites 1  and
33 respectively.  These values  are comparable  to the  values
reported in Reference 1.

Characteristics

     At both  sites  the  recoverable hydrocarbons appear to be
oxidized.   Infrared  spectroanalysis  of chloroform extracts show
the presence of C-OH, C-0 and C -  0 bonds.  In addition aromatic
material  is present.   Figures 7  and  8  show  the IR  traces  for
Sites  II  and  133 respectively.   The dashed line is  a trace of
EPA/API Standard Reference No.  6 Oil.   These traces were obtained
from different  sample thicknesses, therefore transmission values
can be compared only qualitatively from one trace to another.
     The  solvent  extracted  oil has a kinematic viscosity of 950
centistokes as  determined by ASTM method  D 445.   Its specific
gravity, by pycnometer measurements,  is  0.91.
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50 W
l> W
o- »
o S
Soil Waahabillty

     Soil samples were washed with Tlde» and Cltrikeer® at dosage
levels of one pound per ton  of  soil and at 100°P.  Soil washing
bench tests have used in the past, a ten to one wash solution to
soil ratio.   This study used  less solution  than soil at  a 1:3
ratio to achieve the low dosage.   The residual oil and grease was
extracted from  the  soil after the washings to determine washing
effectiveness.  The results  are  shown  in Figures  9  and 10.   The
most dramatic effect  of adding a  surfactant can  be  seen  in the
shift  in contaminant  to the finer particle  size for Site II.
Both surfactants dramatically reduced the contaminant on the >2-
mm and 0.25 to  2-mm sice range  particles.  The contamination is
concentrated in  the <0.2S-on  size range which includes the
wastewater.   This represents more than an  order of  magnitude
decrease for 80%  of  the  sample taken.   The  possibility of
nutrient addition after washing and reappllcation to the site to
allow biodegredation could  be Investigated.  The wastewater con-
taining  the 20% contaminant  enriched fraction was clarified with
the  addition of  sodium hydroxide.    Lime  would  likely  be  a
suitable substitute.   Solids  precipitated upon standing.
                                                                                  Using a surfactant  on  Site  133  soil had no measurable effect
                                                                             over simple particle size separation with water alone.  Seventy-
                                                                             five percent of the soil contains only 14% of the contamination.
                                                                             Again  land application with nutrients is  a possibility.   The
-------
     finer  fractions  in the  wastewater  also  precipitated with

     hydroxide addition.
Ol
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 10


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                                             1

                                      »OJ» "C"
                Figure 9  Lab soil washing results for Site II
                                                                                                     NO


                                                                                               P"71 TOTAL —
                                                                                                                     £
                                                                                                                     £
                                                                                                                               1
                                                                                                Figure  10.   Lab Soil Washing results for Site  »33
-------
      REFERENCES


      1.   Dane*  t Moore,  'Confirmation Study Remedial Investigation -
          Phase  1 Naval  Air  Engineering  Center  Lakehurst, New Jersey*
          Prepared  for  Dept of  the Navy,  Northern Division  NAV-
          FACENGCOM, April 24, 1987.
                                                                                                                         APPENDIX  C
                                                                                                                   MEGA SLUDGE  
-------
        (216)3815371
OJ
                                                                                     MSP
                 CONSOLIDATED  SLUDGE  COMPANY
                     670 SOUTH GREEN ROAD     CLEVELAND. OHO 44121

                                          November 3, 1988

Mr. Jin Sash
Roy f. Westcn, Inc.
Post Office Box 177
Ohnsett Facility - Waterfront
Highway 36
Leonardo, MT 07737

tear Mr. Mash:

Attached are the results of the testing that was performed on the sludge at NAS
Lakehurst.  This demonstration was performed onsita with a one meter MB« Sludge
Press Oewatering System,  The sludge consisted of oil, grease and petroleum.

Using a belt filter press achieved a high pressed solids percentage of 40-45%
from an extremely low feed solids percentage of .15%.  It was necessary to
stabilize the sludge with lima at a rate of 3 Ibe. per 800 gallon* of sludge.
This strengthened the flooc and produced an extremely clear filtrate.

Use of process water had high amounts of partlculate matter that was
precipitated into sludge caka, thereby cleaning the process water virtually
solids free.  Filtrate was of batter quality and extrmly clearer than Inccmln?
recycled water supplied to the press.  Polymers settled out the  solids,
eliminating the brownish-red tint from the filtrate which was produced by the
addition of citra clear surfactant to the soil decontamination unit.

The soil decontamination process produced minima voliros of solids in the
sludge. However, as tne full scale unit is put in service,  the  increase In
solid* will allow for a higher degree of settleabillty.   the higher inooalng
soUds will facilitate tetter mechanical dewatering by either  gravity or
pressure related processes.  In addition, a drastic reduction of polymer should
be realized due to the higher degree of Ionic conditioning within the increased
solids concentration.

In closing, the results conclude that the use of a belt  filter press in this
application can dewater this sludge to a consistency of  greater  than forty
percent and given a higher percentage of feed solids should  proportionately
Increase caka dryness.

Please feel free to contact Mark Marcelletti or myself,  if you have any
questions.
                                               very truly,
                                             r-Ygurs very
                                                  Sales 1 Marketing
                                                                                              TOTAL PERCENT SOLIDS
                                                                                                                   CONSOLIDATED SLUDGE CO.
                                                                                                                                                       DATE
                                                                                                                                                                    8-12-88
Z
MODE
POVER
TIM

0.15
II
80Z
5 minutes

\l
COMPANY NAME ROY
N
F. WESTON
MODE
POVER
TIKE
II
80Z
10 seconds/. 9er
STREET OHMSETT FACILITY
CITY LEONARDO
ZIP CODE 07737
STATE NJ


FOR:
NAS LAKEHURST
                                                                                                                       SLUPCETYTE:  OIL. CREASE.  PETROLEUM
                                                                                                                        DETAILS OF FILTER BELT TESTING
TIME OF DAY
POLYELECTROLYIE
AMOUNT CHEMICAL USEB
CHEMICAL SOLUTION Z
CHEMICAL TEED C.P.M.
SLUDGE FEED RATE C.P.M.
SLUDGE INCOMING t
BELT SPEED F.P.M.
FLOCC MIXER Z
SAMPLE LOCATION
SL'JDCE CAKE I
FILTRATE X
DILUTION WATER/POLYMER
DRY LBS./HR.
DRY TONS/HR.
CHEMICAL LBS./HR.
CHEMICAL LBS./DRY TON
COST /DRY TON ($ /LB.)

IS. 00
33/335






200ml /1 200ml per 12S gallons
0.5
.8/.8
20
0.1S
8.0
80
BLADE
40.45
< .1
NONE
IS
0.01
0.4
40

















































































































































                                                                                               NOTE:  3 Ibs. llm* idded per 800 gal. sludge.
      JC:ta
      Enclosure
                                                                                                        Copyright  1987 Consolidated Sludge Co..  Inc. - All Right* Reserved
-------
CO
ON
I—'
                                HEGA SLUDGE PRESS
What Is HEGA SLUDGE  PRESS?

          MEGA  SLUDGE  PRESS   ("HSP")  is a mobile  filter belt press
used  for  the  dewatering  of  sludges  and   slurries, thus  greatly
reducing their  volume  for disposal,   and at  the sane tine producing
a thick  sludge  cake   that   is easily  transportable  and  can  be
disposed of, without the  problems  of "run off* normally associated
with the disposal  of liquid  sludges.

What Is new about HEGA SLUDGE  PRESS?

          The MSP process is new with respect  to a  number of unique
design  features,   thus solving  the  many   technical and  economic
problems associated  with  sludge dewatering in  the past.

       a)  The MSP unit Is snail, nobile, and conpact, thus allowing
          for low capital cost and minimum nanual labor requirment,
          as well   as  increasing   the  nunber    and  variety  of
          installations for   dewatering.   It has been  designed  for
          all sizes   of effluent  treatment  works,   including small
          and nediun  works  for which mechanical  sludge dewatering
          has  previously    been  uneconomical,  and   often  tines
          inpossible.

       b)  The MSP  unit is   particularly robust,  which facilitates
          extreme corrosion  resistance, a  very Important fact when
          dealing with sludges and slurries.

       c)  MSP  Is very  simple to install,  operate and  maintain.
          Simplicity of  operation is very Important  for plant  use
          in effluent  treatment as the  level of operation expertise
          can vary  widely.   The MSP  can operate for  long periods
          without operator  attendance, and   no complex controls  are
          involved.

       d) MSP's nobility  Is unsurpassed.  Set up   and installation
          costs  are negligible,  and in   some cases  non-existent.
          This   can  conpletely  eliminate   many  unforeseen  costs
          sometlnes  associated  with contract  dewatering.   Each
          trailer is specifically designed   for transport on pickup
          trucks.  It can be taken   to  installations to deal with  a
          variety of  sludges and  lagoons where  other filter press
          operations  are inpossible.   MSP  has rendered  obsolete
          cumbersome filter  presses  which  require  housing in large
          buildings.    Thus,  MSP's   Installation   can   reduce
          transportation costs as   much as  951.   By  reducing  the
          risk  of secondary  pollution, MSP's unique packaged nature
          keeps potentially  expensive labor  costs to a nininun.
       e) Operating costs are minimal.  MSP has a power  requirement
          of only 20.62 amps, which is a major breakthrough.   Other
          systems are characterized by  heavy power consumption  and
          high chemical, labor and maintenance costs.

       f) For high capacity applications a  number of MSP units  are
          installed  and operated  in  parallel.   This  system  has
          major advantages over the   installation of a single  large
          unit.  Great  flexibility of operation is  facilitated as
          individual units can be  taken out of operation depending
          on variations  in sludge loadings.  A  continuous standby
          situation  is facilitated.   In  the  case of  mechanical
          breakdown the operational units can take over  the duty of
          the  non-operational unit.   The  use of  a standby  unit
          provides great economies in capital  cost and  the cost of
          spare parts.

       g) The capital cost  and running costs of the  MSP unit make
          sludge dewatering  an econonic  reality for all  sizes of
          problems.   Its installation  removes  the necessity  for
          sludge drying  beds, sludge  storage and/or  picket  fence
          thickeners.  Its installation  reduces transport costs by
          approximately 95S and greatly  reduces the possibility of
          secondary pollution.

What is the MSP Process?

          A successful  sludge treatment system involves  much more
than  simply the supply of a dewatering unit.   A dewatering system
involves the  use of  various itens   of mechanical  equipment  which
must be  chosen to work in  harmony with each other,  to produce an
efficient  and trouble-free  system.   Each piece  of equipnent  is
dependent on the other mechanical  Items for its efficient operation
and, therefore,  expertise and experience  in the whole  concept Is
important.   The  MSP  Process  is  a  total  sludge  handling  and
treatment system.  MSP  does not simply offer a  piece of machinery
and  expect  the  client to  "get  on  with  it."  We have  a  wide
experience in this  field of work  and can,  therefore, quantify  and
qualify a client's requirements and produce a system suited to that
client's  needs.  The  MSP  Process   could carry  out  a series  of
operations starting  at liquid sludge  pumping and ending  with  the
delivery of thickened sludge to a  suitable transportable container.
without the  need for nanual  handling.  The components  of  the  MSP
Process are as follows:

       a)  Liquid Sludge Pumping.  A  special system is used by
           MSP whereby very viscous and high-solid sludges can be
           pumped at an exact controllable rate, without blocking
           or breakup of sludge floe  by excess agitation.
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              b)   Chemical  Treatment.    A  system  of chemical  storage and
                  mixing  is  provided  that  does not result  in deactivation
                  of   the chemical  by  excess  agitation.   A  very precise
                  means of  chemical dosing  is  provided that can be varied
                  to  suit the  needs of  any particular sludge.

              c)   Sludge  Flocculatlon.   A  system of sludge  flocculation  is
                  provided  thatis specific to  the type of sludge  to  be
                  treated.

              d)   Dewatering  Units.  The  MSP unit  dewaters by  means  of
                  naturalgravity   drainage,  capillary   action,   and
                  pressing.   Its   operation  is very flexible  as both belt
                  speed and roller pressures can be adjusted  to suit all
                  conditions.

                                                The MSP
e)  Thickened  Sludge Conveying.
                a specifically  designed  screw
00
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                     		            Process Involves
           the  use  of   a  specifically designed screw  auger to take
           the   sludge   away   from  the  dewatering  unit,  and  to
           transport  It  to a   belt conveyor, or  outside elevating
           screw  auger  for delivery to a suitable container.

       f)   System Housing.   The MEGA  SLUDGE PRESS Process  can be
           completely assembled. Installed, and  tested on a custom
           designed  common  Stainless  Steel   bast  frame,  In  a
           client's  plant, in the  open or  In  a mobile  trailer
           supplied by   Consolidated Sludge  Co., Inc.  Out  to the
           compactness  of the  system, Consolidated Sludgt Co., Inc.
           can   supply   a mobile  trailer  with  all the  equipment
           pre-lnstalled and   pre-tested.  The trailer  is equipped
           with  lighting,  heating.  Insulation,  ventilation  and
           drainage,     making   the     MSP    Process    totally
           self-sufficient.

The MSP Process has undergone  a six-year development period and has
been  operating successfully   under  full-scale  conditions in  the
United  States.   It has been  supplied  for  the  treatment  of
biological   sludges to   both  Industry  and municipalities.   Plants
have been   installed for the   treatment of excess  activated sludge
from treatment   of  abattoir,   dairy and brewing  waste, as  well as
•flocor" sludge from the chemical  Industry.

What pre-testlng facilities are available?

          Sludge   and    slurries   vary  considerably    in   their
consistency and,  therefore,  in their treatment.   Even with sludge
produced from the same  effluent treatment, processes may vary from
site  to  site.   A  single  sludge  may  even  demonstrate  varying
treatment   characteristics    during  a   yearly  period.    It  is,
therefore.  Important that facilities  art available where necessary
for  sludge  dewatering   tests on  the  sludgt   to  bt  treated.
Laboratory tests  are very  limited  in their value  and pilot-scale
trials  often produce  results that  cannot be  duplicated on   full
scale.  Consolidated Sludge Co., Inc. can provide full-scale trials
with their complete  mobile dewatering trailer.  In  this manner,  a
client  can see  the full  scale  operation working  on the  actual
sludge  in  question  prior  to   purchase.   By  his  own  testing
procedures, he  can satisfy  himself as to  the suitability  of the
equipment.

What types of sludge have been successfully treated?

          a.  Raw primary sewage sludge.
          b.  Digested primary sewage sludge.
          c.  Excess activated sludge from domestic sewage.
          d.  Excess activated sludge from industrial waste.
          e.  Secondary humus sludge from domestic sewage.
          f.  Digested secondary humus sludge.
          g.  High rate biological filtration sludge (flocor).
          h.  Pig slurry.
          i.  Cattle slurry.
          j.  Chemical sludge from chemical precipitation from
              organic wastes.

Capacity of MEGA SLUDGE PRESS

          The  volumetric capacity  of a  single MEGA  SLUDGE PRESS
unit  depends a  great deal  on the  total solids  content and  the
dewatering characteristics of the  sludge In question.  Sludge  flow
up to approximately 3,500 gallons  per hour have been treated.  Raw
sludges  with total  solids contents  from 0.22  - 25.OX  have  been
treated to  give a thickened  sludge cake  between 111 -  681 total
solids content.  The reduction of  sludge volume by the MSP Process
system  Is normally  between 85X  -  95X and  the thickened  sludge
produced no  longer has liquid flow characteristics.

What are the advantages of the MSP Process?

       a)  Sludge  drying beds  are  not required  - Sludge  drying
           beds.   under  most   cllnatic  conditions   art  almost
           Impossible to  operate successfully, with  tht situation
           often  arising  when new  sludge  has  to bt  discharged
           before the old sludge has dried properly.
                                                                                                     There is a  high and costly manual
                                                                                                     drying  beds  requiring  work    in
                                                                                                     conditions.
                                                                                                                            involvement  in  sludge
                                                                                                                            messy  and   hazardous
                                                                                                     The sludge  removed fro* drying  beds has a high  sand or
                                                                                                     stone content making it unacceptable for land disposal.

                                                                                                     A large site area is required  for drying beds.
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d)  Paddle Mocculatqr.   A variable-speed paddle flocculator
    7ssuppliedandfitted complete  -  constructed  from
    stainless steel.

e)  Chemical Mixer.  A mechanical  chemical  mixer is supplied
    and fitted complete,  constructed from stainless steel.

f)  Chemical  Pump.  A  variable  speed  peristaltic chemical
    dosingpump is  supplied and   fitted together  with all
    suction and dlshcharge' pipework and valves.

fl)  Dewaterlng  Press.    Mega  Sludge  Press    Is  supplied
    complete with ABS inlet pipework and drainage  pipework  -
    constructed  from GRP*  and stainless  steel.

h)   Small Auger.  A  stainless  steel  screw auger  and  hopper
     is supplied and  fitted  to convey thickened sludge  from
     the MSP to the outside  of the housing module, complete
     with motor and fixings.

i)  Large Auger.   A  stainless steel screw   auger  and  hopper
    is supplied  and  fitted to convey  thickened sludge  from
    outside the mobile trailer to  transportable  container.

J)  Programmable  Control Panel.    A  complete wall mounted
    NEHA4 controlpanel isTupplied with a  programmable
    controller, necessary software, disconnect switch, motor
    starters, switches,  Indicator   lights,  speed indicators,
    GPN meters, and total aup and  hour meters.

k)  Wiring.   An  electrical  wiring  schematic   specifically
    designed  for   each  individual  installtlon    will  be
    supplied.  The trailer will come completely  wired  as per
    National Electric Codes.

I)  Pipework.  All water, chemical, and drain line locations
    will be submitted on a schematic for each plants'  unique
    requirements.  The MSP drain  line  will have a four  bolt
    flange, the floe  tank will have welded  half  couplers for
    sludge Intake and drain.   It will  then  be fitted for the
    necessary chemical  and water  feed inlet lines, as  will
    the  chemical tank  be  suitably  plumbed.   The trailer
    mounted  units  will   be   plumbed  as  per   ASTM  0-1784
    specifications.

m)  Housing.  A 16-foot (or optional 18-foot) mobile trailer
    is supplied  and  all   necessary MSP  equipment Installed
    and pre-tested.   The trailer  Is constructed  from heavy
    box tubing longitudinals  and formed steel cross members,
    welded into an intergal unit.   The trailer is  covered on
    the outside with  preflnlshed white aluminum  panels.   The
    inside walls and  celling  panels are white KEMLITE  coated
          The  MSP  Process is  no  more  expensive  (capital)  than
          drying beds,  has lower running  costs due to  removal of
          manual  involvement,  provides  instantaneous  drying  of
          sludge,  plus  automatic  conveying   of   sludge  to  the
          transporter.

       b) Pre-thickening of sludge by picket fence thickener  is not
          required.  The  MSP Process  can dewater   sludge straight
          from sources over a wide range of sludge concentrations.

       c) Sludge  storage is  not  required.  The  MSP Process  can
          receive sludge directly from settlement tanks.

       d) With respect  to activated sludge  plants  the MSP Process
          can be set  up to automatically withdraw  sludge from the
          system in-line with sludge  build  up, thus controlling an
          efficient and  correct level of biological  solids in the
          system.  Up to 99.OS B.0.0. removal  have been recorded.  ,

       e) The MSP Process can be easily upgraded.

       f) Major savings  in transport costs  can  be achieved.   MEGA
          SLUDGE PRESS reduces sludge volumes for disposal  by  up to
          951.  This saving far outwelghts MSP's running costs.

       g) The thickened nature of the final  sludge reduces handling
          and odor problems, and  provides for alternative means of
          disposal not available for liquid sludge.  In a thickened
          form  the  sludge  has  a higher  fertilizer  value  when
         •discharged to  farm land  and removes the  possibility of
          secondary pollution of land "run off.*

What Is supplied with a MESA SLUDGE PRESS package?

          The fact that  the MSP Process is a  total sludge handing
and treatment package is emphasized and illustrated by reference to
its components.
                                                                                                     a)   Sludge   Pumping.
                               A variable-speed, high capacity
                              Is  supplied, which  is  particularly
                                                                                                         peristalticpump
                                                                                                         suited  for high  solids or viscous  liquid.
                                                                                                     b)   Chemical Storage.
                                                                                                         suppliedcomplete   with  all  fixtures
                             A chemical storage and mixing tank is
                                                   and  fittings  -
           constructed from stainless steel.
                                                                                                     c)   Flocculation  Tank.   A  flocculation  tank  Is  supplied
                                                                                                         complete withinlet and outlet connection  and  supports
                                                                                                         for  paddle   flocculator  - constructed   from  stainless
                                                                                                         steel.
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         1/4" plywood.  The floors  are constructed with exterior
         grade marine  plywood and  coated with full  width vinyl
         linoleum.   The walls  and ceilings  are also  insulated
         with 1.625*  fiberglass Insulation.  Each trailer  has a
         480  volt HUB8EL  twist  lock connector  mounted on  the
         exterior for  easy installation.   Inside lighting  is 12
         volt and  110 volt  with wall  mounted switches.   A 230
         volt  and  110  volt   wall  outlets  are  supplied  for
         versatality   with   peripheral  associated   electrical
         equipment.
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                 MSP PROCESS GOALS

a) To provide a completely  automatic desludging system that
   will  remove sludge from the system on a daily basis, at a
   rate   related to  sludge build-up  on the  plant, without
   manual  intervention.  MSP  offers trouble-free operation,
   correlating  directly with  profits  associated with  the
   number  of actual uninterrupted sludge dewatering hours.

b) To provide a means whereby the sludge thus removed can be
   automatically conditioned  by chemical, and  dewatered by
   mechanical means,  thus removing  the problems  of drying
   bed operation and manual involvement necessary.

c) To provide a  means by which the dewatered  sludge can be
   automatically  conveyed  to  a  suitable  receptacle  for
   disposal ultimately as land-fill or land spreading.

d) To  provide a  total system  that operates  at a  minimum
   power  requirement,   minimum  manual   intervention  and
   minimum chemical and maintenance costs.

e) To provide a system that is constructed of materials that
   are resistant to corrosion  (GRP and Stainless Steel) and
   allow for long life and smooth operation.

f) To provide a system which is characterized by operational
   siaplicity,  and  minimal   maintenance  features,  which
   equates to low labor and maintenance costs.

g) To provide  a system  that is  economical fro*  a capital
   cost  point  of view,  and reduced labor  and installation
   costs by its pre-packaged and/or mobile nature.
                                                                                            h)  To   provide  a
                                                                                               operation.
                  system that  is well  tried in  full-scale
                                                                                            i)  To provide  a  dewatering  system that has been demonstrated
                                                                                               on  a  full   scale  basis  on  the  application In  question
                                                                                               prior  to possible  purchase.

                                                                                            j)  To provide  a  system  with  an  efficiency of  operation  with
                                                                                               respect    to  'sludge  volume   reductions,   final    cake
                                                                                               thickness,  clarity of  filtrate  and overall  running costs
                                                                                               and manual  involvement which  is a substantial improvement
                                                                                               over any existing  system.

                                                                                            k)  To provide  a  system  that can,  at the clients' request,  be
                                                                                               supplied with  all equipment  installed and   housed  in its
                                                                                               own mobile   trailer  supplied   with all  necessary heating
                                                                                               and lighting, mixers,  tanks,  motors, pumps,  and plumbing,
                                                                                               thus again  greatly reducing  labor and installation costs.
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                            GENERAl DESCRIPTION
               The concept of a mechanical   belt  dewatering  press  is  not
     new, but  those developed to  date  have suffered  from   high capital
     cost, operational  complexity and  short working  life.   However,  the
     concept  of  "mobile"  sludge  dewaterlng  is   a   relatively   recent
     innovation, and with the introduction   of  MEGA SLUDGE  PRESS,  it  has
     been perfected for a variety of industries.

               The MSP  Process was developed to   make sludge dewatering
     an economical reality  for all sizes of treatment  plants.  Special
     attention  was  given  to  producing a   systen  which   operated   on
     extremely  low-power consumption.    The MSP   Process has  undergone
     extensive trials over a six-year  period and  has  proven its ability
     to fulfill  those basic design concept   requirements.   In addition,
     the  simplicity and  compactness  of the  system  allows the   whole
     process  to be  pre-packaged and  delivered  complete,   on a   common
     stainless  steel base  plate thus   reducing  labor  and  installation
     costs for permanent facilities.
O.)
5£             The basic machine consists   of a glass  reinforced plastic
     one piece body, mounted on a  type 304  stainless  steel  frame, which
     Is attached  to the main bast  frame that  supports  the   flocc tank,
     sludge  pump and  drive motor,  and the screen  auger.    The  roller
     arrangement  Is one  large  urethane covered  stainless steel  roll
     around a stainless steel shaft mounted   at the front of the machine
     in aluminum bearing blocks with sealed  bearings and directly  driven
     by the  gear motor  unit through  a Nybrol  and  stetl   coupling.  A
     matching roller behind the driven roll  engages with It  to provide a
     squeezing action on  the pulp.  The tall roll is  an ABS outer case
     roller on  a stainless  steel axle. A   similar but  smaller  roller
     with a  grooved face is  mounted beween the  pressure  roll  and  the
     tail roll  for cloth adjustment and  take up.   All these rollers  run
     with  greaseable  sealed  bearings  mounted   Inside  the  annodlzed
     aluminum   bearing block  housings  which are  fitted  with  adjuster
     screws.  All bearings are  self-aligning FAFNIR type,  sealed  inside
     the  block  housings which are  readily  accessible and  greaseable for
     minimal maintenance  and exceptional  longevity.   All   roller  shafts
     run  the entire  length of each  Individual   roller,  eliminating such
     problems as  warping and 'fracturing.

                Beneath the body, a pair of   cone   idlers on  a common axle
     assist with  the control of the  belt  which  runs partly  Inside  and
     partly outside  the  body.  Where the  cloth nears the outside  of the
     body,   it  bears on  two  3"  urethane  and  stainless   rollers  for
     extended  belt   and  body  wear.  Operational  flexibility  Is provided
     by   means  of  a variable  speed gearbox  and pressure   variation is
     facilitated  by  additional pressure  rollers  supplied with stainless
      steel  yokes,  tension rods,  tie  bean and springs.
                                                                                                              MSP PROCESS DESCRIPTION
          Sludge  is  first  pumped  to   a  flocculation  tank   which is
supplied with a paddle flocculator  driven  by  a  variable  drive motor
which facilitates  variable  paddle  speeds  to   suit all  flocculation
conditions.

          Adding  the dosage  of  polyelectrolyte  solution  either into
the tank  itself  or into  the sludge   inlet pipe  is  facilitated by
means of  a variable-speed   chemical  pump.    This  pump   obtains its
chemical  supply  by  a  stainless  steel  chemical  mix/storage  tank
which is supplied with a mechanical mixer.

          The  suitably-flocculated   sludge   gravitates   from  the
flocculation  tank   to  the  dewatering   press.    The  sludge  is
discharged  onto  the  surface of   the  moving  drainage belt,   where
natural drainage  occurs, with  the  sludge solids  remaining   on the
belt  surface.    The  dewatering   belt carries  the  sludge   solids
through a  series of rollers  which effect a  squeezing   action thus
removing further  moisture.  The   thickened sludge is  removed from
the belt surface  by means of  a fixed  scraper blade.  The  belt then
travels beneath   the machine where  it is  cleaned  by  high pressure
water jets prior  to arriving at the front  of  the machine to receive
further sludge.   Under normal  circumstances the   thickened  sludge
would  fall into  a  screw  conveyor  for   transport  to  a  suitable
container.  All drainage liquid falls  into the  MSP press body  where
it gravitates  to the outlet  pipe.  Wash  water is collected   in  a
stainless steel drain pan and piped away.

          It  should be  noted  that  great flexibility   is achieved
with respect to dealing with variation in  sludge characteristics  by
the fact  that dosage  rates, flocculation  speeds, belt   speed and
roller  pressures are  easily variable.    The system  Is completely
automatic  and  requires  operator  involvement  only  for  chemical
makeup and maintenance.

          Both the sludge feed  punp and the sludge treatment  system
can  be   operated  manually   or  automatically    by  programmable
controller.  With  a known dewatering  treatment  capacity  (obtained
by full  scale  trials) and known sludge build-up   rate (obtained  by
estimate or measurement)', the sludge treatment  system and  feed pump
can be controlled by automatic time  clock to cut  in and out during
a pre-determined  period per day, to allow for removal and treatment
of a  volume of   sludge equal  to the sludge  build-up rate   in  the
treatment  plant.The   thickened  sludge  would    be  automatically
conveyed into a transportable container.  This  process results  in a
very  fine  control  over  sludge concentrations   in  the  effluent
treatment  plant  and  hence  high  operating  efflciences  without
continual manual  involvement.   The only routine  manual  operations
are the periodic  making  up  of a chemical solution  and  the removal
of the sludge container.
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                    PROJECT  DESCRIPTION
          The MSP Process  tendered  by  Consolidated Sludge Co.,  Inc.
will include  all tne  necessary  equipment for  the pumping  of raw
sludge, its  treatment and the  conveying of thickened sludge   to a
suitable receptacle.

       a) The MEGA SLUDGE  PRESS   has  been designed specifically for
          use without  pre-treatnent  by  picket fence  thickener or
          any other means,  and one of its main  advantages  is  that
          large capital  savings  can   be achieved  as this   form of
          pre-treatment  is not   necessary.   The  MSP Process  has
          proved  successful in   dewatering a  wide range  of  inlet
          solids concentrations  (0.22X • 25J).

          Obviously,  the rate of   final thickened sludge production
          (dry  solids   per  hour)   increases  as   inlet  solids
          concentrations increase,  but if higher  daily production
          rates are required it  is  much more economical to  run the
          presses for longer periods   or even provide an additional
          press,  compared   with  the expensive   alternative  of
          pre-thlckening.

       b) Excess activated  sludge  would be pumped  either from the
          excess  sludge sunp  or  the return  sludge  line  to  the
          dewatering plant via variable-speed peristaltic pumps.

          The type of  pump used  for  this  application is critical.
          The capability to pump  high  solids and viscous liquid at
          a controlled rate  without  excess agitation  is essential
          to all  forms of sludge  dewatering plants.  The   type of
          peristaltic pump used Is  specifically designed to  perform
          exactly to the requirements of   the MSP Process and  gives
          fine  flow control without blocking.

           In addition, these sludges   can  be  extremely corrosive  in
          nature, and the peristaltic pump  has an advantage  in  that
           liquid does  not come into   direct  contact  with  any  pump
          part.

        c) Controlled  pump  flows  will first  be  discharged   into  a
          flocculation  tank.   Facilities   will  be  provided   for
          adding polyelectrolyte solution  either  into the feed  line
          to   the flocculator  or  directly   Into the flocculation
          tank.    This   tank   will   be   fitted   with   a   paddle
           flocculator.    The  paddle  mixer   will be  driven  by   a
           variable-speed  drive to give exact  and  ideal flocculation
          conditions.   Pump flows  will  enter   the  bottom   of  this
           tank   and  will   be discharged  by  overflow  chute  to  the
          dewatering  machines.   Various  sludges   require different
           flocculation  conditions  and  the facility  for  controlling
           mixing speed  is  essential.
d) Polyelectrolyte solutions  will  be  made  uo   in  a  suitable
   mixing tank  supplied with  a mixer.   The  mixer   will  be
   designed   to   mix   well  without   de-activating    the
   polyelectrolyte, which can be caused by  high agitation.

e) Polyelectrolyte solution  will be delivered  via  variable
   speed chemical pumps.  A peristaltic pump will  be  used
   for this purpose,  giving a wide dosage   range  with  great
   accuracy.  The  pump will  be mounted above  the  chemical
   tanks and will  feed into either the sludge  feed  pipe or
   the flocculation tank.

f) The suitably-flocculated sludge  will  be discharged  via  a
   GRP  chute   and  gravitate   to  the    dewatering  unit.
   Descriptions  of the  Mega Sludge   Press dewatering   unit
   have  already been  given  but the  following points   are
   emphasized:

     1. The units  are constructed  from  corrosion resistant
        material  of  GRP  and Stainless  Steel  components.
        This  factor  becomes   more   important  if   outdoor
        application is considered   especially  in areas  close
        to the  sea.  Mild  steel,  even  If well   coated can
        have a short life in these  atmospheres.

     2. The  MSP  Process is  designed  to   operate  using   a
        number of  treatment modules operating  in parallel,
        depending on treatment  capacity required.   This  has
        major  advantages over  the  use of a single  large
        treatment unit because:

        Greater flexibility of operation can be achieved;

        A standby facility is always available  if  mechanical
        failure  occurs;(a  warehouse  of parts  is   readily
        available)

        A complete MSP  unit is  always available  which  can
        fulfill  capacity requirements  by  operating  over  a
        longer period.   No standby facility is  provided  if
        only one large unit is used;

        Economical operating  costs can  be achieved  by  the
        operation of  only one screen during  periods of  low
        sludge production; and

        The system  can be  simply upgraded by  inclusion of
        additional treatment modules.

     3. The  dewatering   units  are  extremely    simple  to
        maintain   and   operate,   and   continual   manual
        attendance is not  required.  Consistent performance
        can be  achieved without  any problems of  belt "off
        tracking.'
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           4. The  instantaneous   variable-speed  belt   movement and
              variable  pressure control  gives  great  flexibility  of
              operation  under  all  conditions.

           S. The  whole  system   can   operate  automatically  under
              STATE  OF  THE  ART programmable  controllers.

           6. The  power  requirement for  a  treatment module is only
              20.62  amps.

      g)  The  sludge   deposited on the  moving  dewatering  belt will
          undergo   natural   drainage,    capillary  drainage,    and
          pressing  prior  to  the dewatered sludge  being  scraped from
          the  surface  of  the belt.   The  belt cleaning  system  using
          pressure  jets  is  also installed.

      h)  The  dewatered  sludge from the  press  will   fall  into   a
          screw  auger.    The 7'   diameter  auger  will  convey  the
          thickened sludge  into a  snail hopper  tank which,  in  turn,
          will   serve  as   screw conveyor   for transferring  sludge
          into a suitable container or  roll off.

      i)  Drainage  water   and wash water  are  discharged separately
          for  return  to   the effluent treatment systen,   or in sons
          instances,   pumped directly   back to   the sludge  source,
          where  polyelectrolyte residue   aids  in  further chesical
          dewatering,   therefore,  cutting  polymer   feed rates  and
          costs.

      j)  The  simplicity  of  operation  facilitates   trouble  free
          operation with  little manual attention.    Therefore full
          use  of the  plant can be  facilitated over  longer than five
          hours  per day,  thus providing  for  better economic use of
          the  plant.   Previously  sludge  dewatering systems, due to
          their  complexity,   required continuous  manual attention.
          The  HSP  Process has been specifically designed to operate
          for   long  periods  without manual   assistance,   and  has
          built-in, fail-safe features.
© Copyright  1988 Coniolld»t«d Sludt* Co«n»nv - All Rl«hti
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368
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                                                         FACT SHEET
                                           United States
                                           Environmental Protection
                                           Agency
                                                                                                                               October, 1988
                                   In  Situ Containment/Treatment System
  EPA's Office of Research and Development (ORD) has recently completed
construction of a Mobile In Situ Containment/Treatment Unit designed for field
use to detoxify soils which have been contaminated by hazardous materials
from spills  or uncontrolled hazardous waste  sites. EPA develops such
equipment  to actively encourage  the  use of cost-effective,  advanced
technologies  during cleanup operations.  Once an item  of  hardware is
complete,  it is  tested under field  conditions. After  testing, the plans,
specifications and other information are made available publicly for the purpose
of encouraging commercialization of the new technology. Numerous systems,
including a mobile water treatment unit and a mobile laboratory, have been
developed by ORD, were duplicated by the private sector, and are now
available commercially.
  When spills, or hazardous substance releases from waste sites, contaminate
soils and threaten nearby surface water or groundwater, an effective method
of treating the soil is needed. Excavation and hauling of contaminated soil.
to a secure landfill is one solution. However, this approach is not practical
for  those incidents where a large volume of soil is  involved. An  alternate
commercially feasible approach is to flush the soil in  place with water. ORD
is developing an innovative, improved method for treating contaminated soils
in place at reduced cost, in terms of dollars per pound of contaminant removed.
The technique employs flushing with additives and detoxification by chemical
reaction.

  The mobile In Situ Containment/Treatment Unit, shown left, is mounted on
a 13.1 -m (43-ft) drop deck trailer and includes: a diesel electric generator, an
air compressor, mixing tanks, hoses, a solids feed conveyor, pipe injectors,
soil  testing apparatus,  and  accessory items.  In situ containment  is
accomplished by direct injection of grouting material into the soil around the
contaminated area in order to isolate the released chemicals. The chemicals
are then treated in place by flushing, oxidation/reduction, neutralization or
precipitation. Specially prepared solutions of wash water can be delivered into
highly contaminated soil through 8 injectors. A vacuum well-point withdrawal
system (not shown) creates an artificial hydraulic gradient which draws the
wash solution from the  injectors through the contaminated soil thereby
collecting water-soluble contaminants in the solution. The withdrawal system
has granular activated vapor-phase carbon packs for removal of organic vapors
released during the withdrawal operation.

  The collected chemically contaminated wash solution is processed through
a mobile water treatment unit, where contaminants are removed. Fresh
chemical additives are then introduced into the cleansed wash solution which
is re-injected into the contaminated area. This process is continued until a
point of diminishing returns is reached.

  For further information, contact the Risk Reduction Engineering Laboratory,
Releases Control  Branch, Edison,  NJ. Telephone numbers are:  (908)
321-6926 or (FTS) 340-6926.
-------
370
-------

Mobile In Situ Containment/Treatment Unit
-------
372
-------
            In Place  Detoxification  of
            Hazardous Materials Spills
                                          in Soil
 INTRODUCTION
   Spill incidents can occur in almost any known geographic
 a^ea, contaminating air, water and/or soil. Containment and
 treatment technology for water spills has received the most
 attention and is the furthest advanced. However, in many
 instances, both water and soil are contaminated when land
 spill threatens  a nearby  water body or the groundwater
 table. The state-of-the-art of land spill cleanup has consisted
 mainly  of excavation and hauling to an  approved  landfill
 site  or  possibly flushing of the affected area with water.
 These  methods are appropriate in certain circumstances.
 However, when the groundwater is threatened, when a large
 soil mass is contaminated or when no suitable disposal site
 is available, other approaches may be needed.
   It is the purpose of this effort, funded by the U.S. En-
 vironmental  Protection  Agency  under  contract number
 68-03-2508, to develop  a mobile treatment system which
 allows in place (in-situ) detoxification of hazardous mate-
 rials spilled on soil. Detoxification in this context refers to
 amelioration  of a  spill's effect by chemical reaction. The
 project  goals  were to design  and  demonstrate  a  mobile
 vehicle  capable of encapsulating a 10,000 gallon land spill
 in grout and treating the spilled chemicals in place by either
 oxidation/reduction, neutralization,  precipitation or  poly-
 merization. The approach to achieving the design goals was
 to use  direct  injection of grouting material  into the soil
 around the contaminated area to envelop the spill and isolate
 it from  the groundwater, followed  by detoxification by
 injection of treatment agents. This paper documents the
 results of the laboratory and  pilot tests  and the resulting
 preliminary system design. The vehicle which will be fabri-
 cated and demonstrated during 1978 should be  a  part of
 the EPA spill response arsenal by 1979.

 Project Approach
   The  work was divided into five phases: 1) Laboratory
 Study, 2) Pilot Testing and Design, 3) Fabrication, 4) Test-
 ing and  Demonstration  and 5) Reports. The  information
 obtained during the laboratory and pilot  tests was used to
 develop the final system design and, as anticipated, the end-
 product design was modified from that originally envisioned.

Laboratory Testing
  The laboratory tests had two main objectives:
 Kathryn R. Huibregtse
 Envirex Inc.
 Milwaukee, Wisconsin
 and
 Joseph P. Lafornara
 U.S. Environmental Protection Agency
 Edison, New  Jersey
 and
 Kenneth H. Kastman
 Soil Testing Services Inc.
 Northbrook,  Illinois
   1. To determine if in-situ treatment techniques could
     effectively detoxify chemicals present in various soil
     systems and,
   2. To evaluate,  choose and test various grout types for
  '   their potential use in spill containment.

Choice of Chemicals and Soils
   Various reagents and soil types were chosen for testing
the four types of chemical reactions: oxidation/reduction,
neutralization, precipitation and polymerization. Chemical
compounds studied as contaminants were chosen based on
the following criteria: 1) efficiency of the chemical reaction,
2) common  use of the chemical and 3) potential  risk of
spillage. Treatment agent choices were based on: 1) the haz-
ardous nature of the treatment chemical, 2) its availability,
3) its handling difficulties and 4) the  volume needed for
detoxification of the contaminant. Contaminant concentra-
tions were established by common shipment concentrations,
and the strength of the reactant was established to keep the
detoxification  controllable.  The  chemical   systems  are
shown in Table I.
   Four soil types were also included in the  laboratory
study. It was determined that classification of soils by grain
size would be  most advantageous, since this characteristic
often controls the soils permeability and therefore its amen-
ability  to injection  of treatment  agents. The four soil types
considered were  clay, silt,  sand and gravel.  In order to
simplify data interpretation, it was decided to select  soils to
minimize the  amount of interaction of the soils with the
chemical systems.  This was justified because the objective
of the laboratory study was to evaluate the effects of a soil's
physical  properties  on  in-situ  detoxification  and  it was
thought that the potential interferences from soil chemical
properties could be to  mask important physical  effects
which needed to be defined. Therefore, the following rela-
tively inert soil types were chosen: clay-Georgia  Kaolin;
silt-No. 290 Silica Flour; sand-blended Ottawa Silica Sand
(Flint shot and No. 1 Federal Fine); gravel-trap rock. The
soil gradations were selected to be representative of the
specific soil type to be tested. For example, the amount of
clay or silt in the sand sample was minimal.
                                                       373
-------
                                                                                        In Place Detoxification
                                   Table I: Chemical Reaction Systems Investigated
React ion Type
Oxidation/
P.educt ion
Neutral izat ion
Precipitation
Polymerization
Contaminant
Compound Concentration
Sodium Hypo- 12-15-i Cl
chlorite
Su If uric Acid 3M
Copper Sulfate 75 g/1
Styrene 100*
Reactant
Compound Concentration
Sodium Bisulfite 7.$%
Sodium Hydroxide 1-5N
Sod Sum Sul fide/ 1 .0
Sodiur.i Hydroxide O.I
Persulfate
 Laboratory Reaction Feasibility Testing
   The laboratory  testing  was subdivided into three parts:
 design and fabrication of the testing apparatus and develop-
 ment of the procedures: the actual performance of the tests
 and evaluation  of the results. Two types of testing were
 performed: flow through  tests in which  drainage of the
 system was allowed during  the reaction  and sealed  tests
 which involved  direct  addition of reactant to the soil  with
 no drainage of the soil  allowed.
   In order to evaluate as  many of the critical variables as
 possible,  an  experimental design  was established.  This
 approach varied soil conditions (bulk density and water
 content), contaminant loadings (as percent of the soil void
 space available) and detention time (pressure). The soil and
 chemical  systems were  to be evaluated separately.  After
 initial  attempts and problems involved with developing a
 safe,  uniform and  generally applicable approach to  poly-
 merization in  the soil, this  reaction was not further evaluat-
 ed. Therefore testing  was limited to three reactions and
 four soil types.
   The laboratory  testing apparatus consisted  of a 3.S in.
 diameter  clear column supported by machined aluminum
 bottom and top fittings (See  Figure 1). The column was
 fitted  with an  underdrain support system  for  the  flow-
 through tests and a  porous plate/screen cover to  distribute
 the chemicals  placed  into the column. When necessary,
 regulated air pressure was used to force the reactant through
 the contaminated soil. The sealed apparatus required elimi-
 nation  of the base and drainage  holes. Columns of both
 acrylic  and  clear PVS  plastics were used since  neither ma-
 terial  was  resistant  to  all  of the chemical species tested.
   The testing procedure involved mixing specified amounts
 of soil and water and  packing this mixture to incremental
heights to achieve a specified soil bulk density. These soil
columns were  then contaminated  with  liquid  to fill a
certain  soil  void volume,  the  treatment agent added and
samples collected  at the underdrain.  If sealed tests  were
performed   on  a  system  the contaminant/reactant/soil
 mixture was allowed to stand for a given time and soil core
 samples were taken and analyzed.
                                             CHEMICAL ENTRY
                                                PORT
            U:iU[il UP.AIII
             SYSTEII
                                            «  SUPPORTS
                                   FITTI'IC
Figure 1 : Laboratory Testing Apparatus

   Initially, flow-through testing  only was  to  be imple-
mented.  However, it soon became  apparent  that this
approach was not feasible  for the fine grained clays. The
                                                         374
-------
       In Place Detoxification
high pressures  required to force the reactant  through  the
soil caused  short circuiting along the column sides and no
detoxification occurred. Therefore it was decided to test a
surface treatment method (sealed tests) for the clay systems.
   The  data collected from all  laboratory  testing were
evaluated and the percent of contaminant treated was cal-
culated along with the residual concentration in the treated
soD. Statistical  analyses  of these results  using  ANOVA
design and F tests were used to identify which of the vari-
ables  had significant effects on the efficiency of the reac-
tion. The results indicate that both soil type and reaction
type significantly affect the degree of detoxification, along
with the three internal variables (soil conditions, detention
time and loading).
   The efficiency of in-situ treatment in gravel was much
lower than with other soils (See Table II). This is a result of
most  of the contaminant rapidly percolating  through the
gravel prior to treatment. However, for the contaminants
entrained on the gravel, the reaction efficiency ranged from
95-99%.  The overall efficiency  of the neutralization reac-
tions  was also lower since  a pre-reactant  water  rinse was
required  in order to reduce the heat of reaction. Precipifa-
tion reactions  were more efficient than anticipated. This
may be due to the blocking affect of the precipitate which
clogs some of the voids and forces the treatment agent to
 flow into other contaminated areas. Redox reactions were
'generally quite efficient under all conditions. The detention
 time was critical for sand detoxification indicating that too
 high a pumping rate will be detrimental in final treatment.
   The effectiveness of sealed detoxification (surface treat-
 ment) was not anticipated. As long as void saturation was
 not exceeded, the  treatment agent entered the fine grained
 soils and mixed to a degree which detoxified  most of the
 contaminant. This apparent  mixing in the small void sizes
 was not expected. Reduced  reaction  efficiencies were ap-
 parent  for  precipitation  because the precipitate did block
 the  reactant's path into the soil. Overall, even this reaction
 was quite effective. The main problem with a sealed system
 is that the volumes which can be treated are limited to voids
 available for the reactant.

 Grout Evaluation
   The second  objective of  the laboratory testing was to
 evaluate the grout which could be used for encapsulation of
 a spill. The main types of grout available include particulate
 grouts such as  cement and  bentonite and  chemical grouts
 which are  mainly  Acrylamide  (AM-9), urea-formaldehyde
 resin, lignin or silicate based materials. Particulate grouts
 are  generally used  in coarse grained soils since  they have a
 relatively high viscosity due to their suspended particles in a
                                     Table II: Summary of Laboratory Test Results

Soil
r.vH
•V-.r.d
TonJ
S.V.u1
s;it
Gilt

iilt
Silt
Crave 1
rrave 1
Travel
r.ravcl
Clay
Clay
May
Clav


"cac t icn
••ci^
^•ido.x
TPT
•'.vo
•'ciJ
redox

PPT
,'vo
.-' c i d
"edox
PPT
Avp
.•' c i d
rcdox.
rrr
Avo
-Based on the

Test Ty«e
Flo-.-/ Thru
Do1.) 7l-.ru
Ho.-.1 Thru
Flo.-/ T.'iru
Do / Tliru
rlo: Tliru

F 1 ovi Th r u
rlf;-..- Thru
F 1 CM Th r u
rlc-.' Thru
rio'v Thru
rlrr; Thru
Sealed
Scaled
Sealed
Scaled
/total atrount
P.an«je of
Effectiveness-
3.4-52.2
10. '.-66. 4
10.2-85.8
( 3.^5.8)
30. 2-n
-------
                                                                        In Place Detoxification
water base. Chemical grouts are generally in solution form
and can  be used to grout finer grained soils. One of the
most commonly used  chemical grouts is  AM-9 which can
                              be used to grout both clays and silts. However, AM-9 has an
                              acrylamide base which is toxic to groundwaters. Therefore
                              it was not considered suitable for the spill containment
                              application.
s

ui

03
C
O
CO
  O
  ca
  o
  i
  a
  a
  O
  o
  o
      0.160
     o.Uo
     0.120
     0.100
     0.0300
     0.0600
     0.0^*00
     0.0200
     0.0
                      INST. A INST.
                      GEL   GEL
               ,INST.
               GEL
A9M  A8M
                                   QM
 INST
•GEL
                                          2 M
                              5 M
               I5M\58MA     |2M   60 M
               SHRINKCCF        •
               17 M
               I7M
                10 HR  L.	
           ,95 M  «  810HR  >
            •.   n *"2O5 M »-|
                                   r-,
                                   GEL
 40HRXX     10 HR
 V.WEAK JBOM  FT.OC GEL
  G£L

                            NO GEL    NO 06L
                                                     GEL

                                                     GE1
                                                  8HR
                                                             ZONE OF  OPTIMUM  COMBINA-
                                                             TIONS FOR GEL FORMATIONS
                                                                      6 TIME.
             NO GEL   NO GEL   LTGEL
            •       •       »a HR
               NO GEL
                                 NO  GEL
                                        1
                                          KEY

                                          AMOUNT OF SODIUM SILICATE
                                          IN TOTAL GROUT VOLUME

                                               33% (BY  VOLUME)
                                               26* (BY  VOLUME)

                                               162 (BY  VOLUME)

                                           M -  MINUTES
                                           H =  HOURS
                                           INST.  = INSTANTANEOUS  GEL
                                                    FORMAT I ON
                                           FLOC.  - FLOCCULATED  GEL
                                                    STRUCTURE
              0          0.010        0.020   ,     0.030
          RATIO OF  COPPER  SULFATE TO  SODIUM  SILICATE  CY WEIGHT
Figure 2: Affect of Various Chemical Mixtures on Gel Formation for Silicate Grout
                                            376
-------
       In Place Detoxification
   Evaluation indicated  that bentonite/cement or silicate
grouts would be most  feasible for spill containment. De-
pending on both the soil and chemical characteristics, one
may be more applicable than the other. Both systems are
environmentally acceptable, since the bentonite is a natural
clay product and may eventually  resorb into  the soil and
the silicate grout  may  break down  with  time;  thus long
term adverse effects will be minimized.
   There are several silicate grout formulas in general usage.
The silicate grout  used  in this survey was formed using a
mixture  of  sodium  silicate, sodium bicarbonate  and  a
copper sulfate  catalyst.  Extensive  laboratory  testing was
performed to  establish the most feasible  dosages.  The
results are plotted in Figure 2. It  is anticipated that this
type of presentation  will be included in the final systems
operation and  maintenance  manual  with  instructions for
choosing an appropriate mix. Chemical tests to determine
the grout's resistance to  treatment  chemicals were  also
performed.  The results  indicated  that  the  silicate grout
while resistant to bisulfite,  hypochlorite, sodium sulfide
and  copper sulfate,  had very low  resistance to  acids and
relatively low resistance to bases. This  was expected because
the silicate is an alkaline material and the gel is affected by
pH. When  a  high pH occurs, a bentonite grout  would be
recommended.
   The final output of this effort was to develop an approach
for establishing a specific chemical's  treatability  by in-situ
techniques.  This involved determining if neutralization,
oxidation/reduction  or precipitation would detoxify the
hazardous material and establishing which type of grout
would be most resistant  to chemical  penetration. These
results will be presented in the final report and Operation
and Maintenance Manual in tabular form for quick reference.

Pilot Testing
   Based on the results of the laboratory tests, two reaction
types and two soil types were chosen for pilot scale evalua-
tion.  Precipitation and redox reactions were selected to
further define effect of solids formation. Sand and clay soils
were  chosen so that both flow-through and  sealed pro-
cedures could be tested on a larger scale. The main objec-
tives  of the pilot  testing  were:  I) to determine  if the
detoxification procedure  was feasible on a larger  than
laboratory scale and  2) to establish critical parameters such
as pumping rate, injector placement and back pressure, for
consideration in the development of the final system design.

Testing Equipment and Procedures
   Special test cells were constructed for the two types of
tests as illustrated in Figure 3. Both were made from coated
plywood, the larger box  having heavy reinforcing. Addi-
tional tanks, pumps, tubing and mixers were procured and
used during the test operations, as needed. The test pro-
cedures  for the surface and  injection treatments were quite
different. The surface  testing was basically similar to the
laboratory tests. The soil and water were compacted in the
                            PLEXIGLASS
                              THK.
                                                                                 .0
                                                                                 »


                                                                               SAND TEST BOX
Figure 3: Pilot Test Cells
                                                           377
-------
                                                                                        In Place Detoxification
 box to a given bulk density  and the specified amount of
 contaminant was sprinkled over the surface and allowed to
 migrate. After 24 hours, the reactant was sprinkled on  the
 soil surface and allowed to detoxify the soil for 48 hours.
 Core samples were taken at specified locations in the box
 and analyzed for contaminant concentration.
    The flow through testing required that the box be filled
 with 5600-5800 Ib of sand which was placed and compacted
 in  3.5 cm layers to achieve the desired bulk density. Water
 was added to yield  a 5% water content. The contaminant
 was again placed on  the surface, and the reaction was per-
 formed the same day as contamination. An injector and wet
 well were placed on opposite  ends of the box and then  the
 specified volume of reactant was forced through the injector
 into  the  soil. After the  reactant  was pumped into  the
 system, a volume of water was injected to rinse the soil of
 excess reactant. Throughout the pumping period, the wet
 well was continuously emptied into a separate holding tank.
 After all liquids were pumped into the soil, core samples
 were collected and analyzed for moisture content and con-
 taminant concentration.
    Two pilot  grouting tests were also performed to aid in
 choosing injector types and establishing anticipated pump-
 ing pressures and to define some of the problems associated
 with grouting. Various mixes of grout were pumped and  the
 resultant grout wall  observed and tested, where possible.


 Results of the  Pflot Tests
   Data on the percent of contaminant removed in the pilot
 tests  are shown in Table  II. This measure of extent  of
 reaction was based on residual concentrations found in the
 soil as opposed to the total amount of contaminant which
 had reacted as calculated for the laboratory testing. This
 percent reaction is generally higher than the contaminant
 percentages, but for a large system it is a better measure of
 the overall effectiveness of detoxification. However, direct
 comparisons to the laboratory results should not be made.
   The effectiveness of detoxification for all  of the  pilot
 tests was quite high. As expected, the geometry of reactant
 injection and the shape of the pilot study box affected the
 detoxification. When  evaluating the results of flow-through
 testing, it was apparent that  the detoxification was most
 effective within a  radius of 1.5 ft from the  injector. How-
 ever, detoxification effects did extend beyond  this radius.
 The surface  treatment results  reflected  those predicted
 from the laboratory testing. The redox reactions were very
 effective, removing most of the contaminant  which was
 entrained in the surface layers. Precipitation reactions were
 less efficient than the  redox reaction. This can be attributed
 to the blocking of voids by precipitate formation. Shrinkage
cracks which formed  when the surface dried allowed more
effective reaction in some of the lower layers. However, as
with the redox system, the majority of the contaminant
entrained in the surface layer was detoxified.
  Evaluation of the  grout test results indicated that injec-
tion of chemical  grout  on an angle was  possible,  while
grouting near  the soil surface was not feasible because of
short  circuiting  caused by grouting pressures being larger
than the soil  over burden weight. The paniculate grout '
was difficult to handle  in the shallow testing box and the
 only injection device which proved feasible was one with a
 single outlet hole.
   The pilot  tests also indicated:  1)  the importance of
 driving an  injector directly into the soil  as  opposed to
 boring  and  then placing the injector, 2) the necessity of a
 wet  well equipped with a self priming  pump for liquid
 removal,  3) the need for pumping systems equipped for
 pressures up to 80 psi., 4) the requirement for volumes of
 rinse water was not as critical as originally anticipated, 5)
 the back-pressure caused by higher void volume loadings of
 contaminant reduced  the  forward flow  rate significantly
 and 6)  the neutralization chemicals could be added using a
 multi-holed injector (which allowed for much  faster treat-
 ment).  It was determined that pilot test grout gel times
 were shorter than in the lab  and  that  the  chemical grout
 injection  could  be  controlled by the volume added while
 the particulate grout addition was best regulated by pres-
 sure in the injection lines.

 Prototype Design

 Preliminary Design
   After the pilot tests were completed, the design of the
 prototype system  was begun. Much  of the information
 obtained  throughout both the laboratory  and pilot tests
 significantly influenced the design.  A process  and instru-
 mentation diagram is shown  in Figure 4 and  a layout  is
 shown in  Figure 5. The system provides much flexibility for
 spill  cleanup. The grout or chemicals  are to be mixed in
 alternate  batches  in the two 1500 gal  fiberglass tanks.
 Batching  eliminates  potential problems  associated  with
 exact mixing of grout constituents at the point  of injection
 and thereby allows closer system control.
   Two pump types were included.  For grouting, positive
 displacement pumps will provide the most control and the
 simplest  operation, however  they were  not  sufficiently
 chemically  resistant for chemical  injection which will be
 accomplished by the air pumps, available in HasteUoy C. It
 was also determined that multiple pumps  instead of exten-
 sive manifolding of injectors would allow more control of
 the volumes pumped into the soil. If necessary, the injectors
 can be  manifolded  in pairs to allow  higher pumping rates,
 however this  approach may not always be feasible when
 difficult soil conditions are  encountered. The volume  of
 liquid added is  to be metered and totalized, since in most
 instances  the chemical solutions will be added  until a cal-
 culated amount is pumped into a specified area. The injector
 will then be withdrawn a certain distance and the pumping
 process repeated.
   The vehicle will be equipped with a diesel-electric genera-
 tor and an  air compressor. An "air-hammer" type device
will be used to drive the injectors (1V4 in. OD, 1 in. ID) into
 the ground. Separate multiholed injectors will be used for
chemical  addition.  Since  the cost of  chemical resistant
injectors would  be  excessive, standard  steel pipe injectors
will be replaced when they corrode to the point where they
are no longer  usable. All components would be accessible
either on the vehicle or from the side. The controls will be
centralized on a panel permanently mounted on the truck.
Accessory equipment will include standard  test apparatus
                                                      378
-------
      In Place Detoxification
to measure  soil conditions and  chemical concentrations,
well  points for use as wet wells, some small air pumps to
empty wet wells, and a surface holding tank.
   Costs are presently being developed and this design may
be modified depending upon  the complete economic con-
siderations.
                                     Table III: Summary of Pilot Testing Results
Test Conditions
Results
Test Avg Cont Avg Percent
Ho. Media Containment ^loading Location Cone Removal (Tot)
1 sand MaOCI


4 sand NaOCI


2 sand CuSOt,


3 sand CuSOi,


7 clay JlaOCl


8 clay llaOCI


9 clay CuSOt,


10 clay CuSOi,


25 top
mid
1)0 1
50 top
mid
bot
25 top
mid
bot
50 top
mid
bot
25 top
mid
bot
50 top
mid
bot
25 top
mid
bot
50 top
mid
bot
411
2066
337'i
2539
2218
6606
1040
1253
1262
2096
5791
8530
20306
413
28
20306
413
28
8197
2653
86
8197
2653
86
2 Removal 100 x = (concentration of contaminant in - concentration
soli before treatment treatment
Cl
HI
95.2
97.6
Ct
5T.3
100
97.3
Cu
71.5
8?.2
C8.7
Cu
7^.7
94.9
96.5
Cl
99". 7
85.0
60.7
Cl SO,
99.9 99.9
82.3 99.85
C5.7 99.82
Cu
75". 8
99-5
76.7
Cu
70.6
76.0
76.8
after)
Avo. Percent
P.enoval (Inj)
SO,
95778
99.79
99.76
s?j
99.92
99.90
99.89
Cu
89.5
89.7
88.2
Cu
8873
97.9
97.5
—
-
-
_
-
-







concentration of contaminant In
soli before treatment
                                                       379
-------
                                                                                       In Place Detoxification
                                                                                   CCXtNT
                       . •   - -•     II  i .1 '     l
                        ••.OA   iiJiJJ   1!
 Figure 4: Process and Instrumentation Diagram of Prototype Unit
Design Limitations and Decision Matrix
   The  limitations  of in-situ detoxification  techniques
either through surface treatment or direct injection of grout
and  chemicals  must be understood before the  prototype
equipment is  used.  When  a land spill  occurs, alternative
approaches should be evaluated and the most time and cost-
effective approach  for the  specific  situation  chosen. In
order to determine if in-situ detoxification is most efficient,
a decision matrix will be prepared. This matrix will present
an approach for evaluating  the feasibility  of grouting  and
chemical injection, as well as surface containment and treat-
ment. Among  the critical  variables are type of chemical
spilled, interaction with the soil,  the soil's "groutability"
(permeability, void loading, geometry, water  table level,
etc.), soil volume contaminated,  feasibility of excavation
and  availability  of treatment  supplies  and  manpower.
   This equipment will not be applicable  to all land spills.
However, there are many situations in  which it  will be a
feasible technique. The surface treatment approach may be
desirable in many cases even if  the spilled soil  is to be
removed and  transported to a landfill. This pretreatment
will protect equipment and  may even allow redefinition of
the removed soil as non-hazardous. Grouting in and of itself
will be feasible even when direct chemical treatment is not
possible. Construction  of  a grout layer  will protect the
                                                     380
-------
      In Place Detoxification
ground water if excavation is incomplete or if rain rinses the
area. Although grouting will be limited to relatively coarse
grained  sand and gravel materials, it is these soils that allow
permeation of the contaminant through the soil structure
and into the groundwater.

Design Changes
   Several changes have been made  in the initial design con-
cept. Most significant is the addition of a surface treatment
technique for  fine grained soils. Polymerization was limited
to a few possible materials and was determined to be too
dangerous to implement in a field situation. The pilot tests
indicated that  it was critical to meter liquid  flows indivi-
dually so the original design which included a high capacity
pump with extensive manifolding of injectors  was changed
to include a larger number of lower capacity pumps with
much less manifolding.
   It was also  determied that the pumping rates for chemi-
cal  injection should be  relatively  low to allow effective
reaction. Therefore the overall  time required for treatment
will be longer than anticipated.
 CONCLUSIONS
. 1.  An in-place treatment technique has been shown to be
    an effective land spill cleanup on a laboratory and pilot
    scale basis.
 2.  Grouting technology appears to be an effective method
    to contain spills and thereby minimize potential ground-
    water contamination.
 3.  Where small grained soils (silts and clay) preclude the use
    of injection  equipment, a surface  treatment using a
    diluted reactant  provides an efficient way to detoxify
    land spills of applicable hazardous materials.
 4.  In order  to establish the most time and cost-effective
    method for land  spill cleanup, the limitations of the  in-
    place  detoxification as  well as  specific spill variables
    must be considered.
 5.  A stepwise approach to containment by grout injection,
    followed  by  chemical treatment seems to provide the
    most flexible treatment system.

 ACKNOWLEDGMENT
    'The work on which this paper is based was performed
 under Contract 68-03-2458 with EPA's Oil and Hazardous
 Materials Spills Branch, Industrial Environmental  Research
 Laboratory (Cincinnati) Edison, New Jersey."
Figure 5: Preliminary Layout of Prototype Unit
                                                         381
-------
382
-------
                           FIELD EVALUATION OF IN SITU WASHING
                       OF CONTAMINATED SOILS WITH WTER/SURFACTANTS1

                                        James Nash
                           Mason & Hanger-Silas Mason Co., Inc.
                                       P.O. Box 117
                                Leonardo, New Jersey 07737

                                    Richard P. Traver
                     Hazardous Waste Engineering Research Laboratory
                                 Releases Control Branch
                                 Edison, New Jersey 08837

                                         ABSTRACT

     Since 1981, the Releases Control Branch of the Hazardous Waste Engineering Research
Laboratory has been developing techniques to wash contaminated soil 1n place (In situ).
The project Includes: design and fabrication of the hardware to carry out the washing,
evaluation of surfactants to do the washing, determination of which geological  character-
istics to use to judge the appropriateness of 1n situ washing, development of a monitoring
and reporting system, evaluation of two candidate sites for the field testing of the  hard-
ware, and a pilot treatment study at a contaminated site.

     This paper summarizes the design and development of_the In Situ Contalnment/Treat-
ment Unit (ISCTU) and the evaluation of surfactants for 1n situ soil washing.  The empha-
sis Is on work completed at Volk A1r National Guard Base, Camp Douglas,  Wisconsin. The
work shows that surfactants will remove otherwise obstinate contaminants from soil even
without mechanical agitation of the soil. However, subsequent treatments of the surfactant
laden leachate 1s an unresolved problem.
INTRODUCTION

     In situ soil washing 1s the term to
describe washing of contaminated soil wlth-
  This report 1s a summary of work per-
  formed 1n partial  fulfillment of Con-
  tract Numbers 68-03-3113 and 68-03-3203
  under sponsorship of the U.S. Environ-
  mental Protection Agency.  The U.S.  A1r
  Force through Interagency Agreement
  IPRW 57931283-01-0 with the U.S. EPA
  has also sponsored much of the work
  reported here.  This paper discusses
out excavating.  The washing Is accomplished
by applying a liquid at or near the surface
the key activities of four projects:
"Treatment of Contaminated Soils With
Aqueous Surfactants", "Retrofit of the
In Situ Containment and Treatment Unit",
TJfiemlcal Countermeasure Application at
Volk Field Site of Opportunity", and
"Site Characterization and Treatment
Studies of Soil and Groundwater at Volk
Field."
                                            383
-------
so that the solution will  flow down
through the soil  structure.   By substitu-
tion, emulsiflcatlon and/or solublUzation,
contaminants are  removed from soil  parti-
cles and held 1n  the liquid phase.   The
liquid will then  percolate down to  a
perched or unconflned aquifer where It
can be removed through withdrawal wells.
Soil Soils with permeabilities (a measure
of the ability of a fluid to pass through
the soil) of greater than 10-* cm/sec
should be suitable for this technique.

     At this time, 1n situ soil washing
with a surfactant 1s not a field useable
remedial technique.  Although surfactants
do remove obstinate contaminants from
soil, treatment and disposal problems
after removal have not been solved.
Petroleum hydrocarbons and PCBs, which
have low mobility 1n soil .structures, were
removed from soil 1n laboratory tests.
Problems still remain regarding separation
of the surfactant from the contaminant and
the water.

Treatment of Contaminated Soils with
Aqueous Surfactant?

     Soap, a sodium or potassium salt of
fatty adds, was the earliest man-made
surfactant.  Credited to the Phoenicians
1n 600 BC. there had been no additional
surfactants developed until the twentieth
century.  The relatively recent develop-
ment of surfactants has Included sulfo-
nates and ethoxylates.  In work conducted
at Texas Research Institute1 for the
American Petroleum Institute, two commer-
cially available surfactants were Identi-
fied for use In lab tests to wash gasoline
from Ottawa sand.  Those two surfactants,
used together, were an ethoxylated  alkyl-
phenol and a dodecyl benzene sulfonate.
The reasons for their selection at  that
time were low Interfaclal tension and
compatibility with salts found 1n soil.
The API work as well as studies conducted
under this EPA program revealed that
surfactants In water solutions may
hydrolyze and form floes that block soil
pores or will block the soil pores  with
surfactant particles called micelles.
     Blockages are also caused by the
surfactant/contaminant emulsion.  The use
of two surfactants Is required because the
ethoxylated alkylphenol  retards the for-
mation of floes and micelles while the
sulfonate 1s required for cleaning.  The
surfactants should be easy to mix with
water and should not cause the fine soil
particles to be suspended in the wash
solution.  Mobilized soil fines will block
flow at the narrow passages between soil
particles.  A "mat" 1s formed 1f enough
passages are blocked along a continuous
front.  These mats halt fluid flow and
thereby stop the washing process 1n that
area.  Aging studies of surfactant solu-
tions were performed to observe the forma-
tion of floes.  The measurement of turbi-
dity over time was used to demonstrate the
effect of blending.  The surfactants
selected for blending in this work were an
ethoxylated fatty acid and an ethoxylated
alkyl phenol.  See Figure 1.
       no

       10
        M
                22  24
                            14
       I  ISO
Figure 1.
               Particle growth as measured
               by turbidity increase. For
               two surfactants  and their
               blend.
      The crystalline floes  formed during
 these measurements blocked  the pores of a
 column of medium to fine sand.
                                           38«
-------
      The first washing tests were  run  on
 a shaker table and  the next  test series 1n
 columns.  Contaminated soil  was compacted
 1n 3 1n. Increments Into 3 1n. diameter,
 5 ft high glass tubes.  The  tubes  were
 fitted with  nlppled glass caps at  the
 bottom and top.   A  pressure  head of 30 cm
 of surfactant  solution was applied to  the
 surface of the contaminated  soil.  The
 soil  pores were, therefore,  experiencing
 saturated flow of the  surfactant solution.2

      The soil  used  for the laboratory  work
 was a Freehold series  typlc  hapludult  from
 Clarksburg,  New Jersey.   It  was selected
 because of Us grain size distribution and
 similarity to  soil  at  CERCLA candidate
 sites 1n EPA's Region  II.  Ten percent was
 silt  or clay,  eight  percent  gravel and 80%
 coarse-to-flne sand.   Its permeability of
 10-4  cm/sec  1s at the  low end for  1n situ
 washing.   Nine to eleven  perceijt oT~the
 soil  was HC1 soluble.  Of the crystalline
 structure, 98% was  quartz and 2% was
 feldspar.  Only  0.12%  was organic  carbon
 which 1s  a low value and  accounts, 1n
 part, for  a  low  cation exchange capacity.

      A  topped  Murban crude oil In methyl-
 ene chloride was  applied to the soil.
 This  contaminant  was selected because It
 contained many organic types  Including
 aromatics, polynuclear aromatics,  allpha-
 tlcs, polar  and  non  polar compounds.  The
 methylene  chloride was allowed to evaporate
 and the  soil was  aged prior to being
 loaded  Into  the test columns.  Other con-
 taminants. In  separate tests, were chloro-
 phenols and  a  polychlorlnated blphenyl.

      Gas chromatographlc analysis  showed
 that  ten pore  volumes of surfactant solu-
 tions passed through the columns  removed
 88% of the topped Murban crude oil  and 90%
 of the PCB's.  Using high performance
 liquid chromatograQhy (HPLC), It was shown
 that chlorophenols were removed with the
 water alone.   Surprisingly,  removal In the
 column studies, where there  1s a  low level
 of mechanical washing,  was better  than re-
moval In the shaker  table studies.   Start-
 Ing at 1000 ppm contamination 1n the
columns, removal efficiencies as high  as
98% were reported.
'Control  of  In  S1tu  Hashing Fluids

      Accelerating the  natural tendency of
 a  contaminant  to migrate through the  vadose
 zone Into the  groundwater Is the basic
 purpose  of  In  situ  soil washing.   In  order
 to do this  so  there Is no adverse  Impact
 on an aquifer, rigid controls must be
 maintained  to  assure the contaminant  Is
 captured.   The EPA's In Situ Containment
 and Treatment  Unit  (ISCTUFwas designed
 for this purpose.   The drawing 1n Figure 2
 represents  the parameters (of an hydraulic
 budget)  that were considered for the
 (ISCTU).3   They are: recharge G., discharge
 Da, treatment  system flow R, evapotrans-
 p1ration E, precipitation P, natural
 groundwater flow Uj, and Induced ground-
 water flow  U?.  Variation 1n these
 qualities will  change  those Hems 1n  lower
 case letters;  vadose zone thickness w,
 mounding m, drawdown (he-hw), and radius
 of  Influence re (not to be confused with
 the radius  of  capture).
      Figure 2.  In situ parameters
                                          3S5
-------
 Figure 3 Is a simplified drawing of the
 ISCTlJ, which Is equipped with recovery and
 delivery pumps, batch mixing and propor-
 tional-additive metering pumps, flow rate
 controls, pressure and flow meters, and a
 volatile organic stripping tower.  Any
 treatment of groundwater requiring more
                                     than air stripping must be done  "off-
                                     board."  A microcomputer/data  logger  Is
                                     used to monitor environmental  conditions
                                     and the effect of pumping and  recharge on
                                     the aquifer.  To do this, depth  gauges,
                                     flow meters, moisture meters,  and a weather
                                     station are connected to the data logger.
                         A. AIR DIAPHRAGM PUMPS

                         B. PROPORTIONAL CHEMICAL
                          ADDITIVE METERING PUMP

                         C. INPUT MANIFOLD
              MAIN ELECTRICAL
                BREAKERS
                                       D. PROCESS MONITOR RECORDER

                                       E. WATER PUMP

                                       f. BATCH CHEMICAL METERING PUMP
                                      CHEMICAL MIXING TANK .
                                                     PULLOUT OPERATOR'S PLATFORM
DIESEL ELECTRICAL
  GENERATOR
                                            INJECTION MANIFOLD

                      Figure 3.  In Situ Containment and Treatment  Unit
Site  Selection  for  the  Field  Evaluation

      In September 1984  the U.S.  A1r Force
and the U.S. EPA started  1n a joint effort
to evaluate ^  situ washing technology.
The primary objective of  the  project was
to demonstrate  full-scale feasibility.
A secondary objective was to  develop a
more  comprehensive  strategy for  the decon-
tamination of fire-training areas  of all
A1r Force and Department  of Defense (DoD)
Installations.  The following criteria
were  used 1n selecting  a  site suitable
for full-scale  soils washing  research.
A site of less  than one acre  was desired
to reduce soil  variability and reduce
sampling costs.  Because  soil  washing 1s
best  suited for permeable soils, a sandy
site was sought.  Contaminants at  the
site  were to be common  organic chemicals
found at many other A1r Force sites,
I.e., trlchloroethane,  benzene,  toluene,
trlchloroethylene.  Officials  of the
selected installation and responsible
environmental agencies  would  need  to be
cooperative.
                                          Preliminary screening of candidate
                                     sites was  accomplished through a review
                                     of A1r Force Installation Restoration Pro-
                                     gram  (IRP)  reports.   Over sixty reports and
                                     nearly 800  sites were screened.  During
                                     the review, 1t  was  apparent that most sites
                                     with  organic chemical  contamination fell
                                     into  two common categories:   sites of fuel
                                     spills and  fire training  areas.

                                          Fire training  areas  were especially
                                     suited to this  research because of their
                                     limited size and range of contaminants,
                                     which Included  chlorinated solvents, fuel
                                     components  and  lubricating oil.  Fire
                                     training areas  are  found  at  almost all  A1r
                                     Force Installations  and,  because of the
                                     long-term fuel  and  solvent dumping at these
                                     sites, they have significant off-site pollu-
                                     tion  potential.

                                          Following  this  careful  review, a fire
                                     training area at Volk  Field, Air National
                                     Guard Base,  Wisconsin, was selected as  a
                                     research site.   Historical  records Indi-
                                     cate  that the Volk  fire training area may
                                           386
-------
 have* been established as early as World
 War  II and has routinely received waste
 solvents, lubricating oil, and JP-4 jet
 fuel.  Although It Is Impossible to deter-
 mine the quantity of chemicals that soaked
 Into the ground versus the amount volatil-
 ized and burned 1n fire training exercises,
 one  estimate 1s 52,000 gallons.  Measure-
 ment of volatile organlcs from groundwater
 samples taken 1n 1980 directly below the
 fire pit showed chloroform, tMchlorethane,
 tMchlorethylene, benzene, toluene, and
 ethyl benzene totaling above 50 mg/Hter.4

 Site Studies

      Two site studies were made at the fire
 pit  area during 1985.  These studies were
 conducted to thoroughly understand the
 hydrology and chemistry associated with
 the  contamination have produced as a
 by-product a great deal of data and In-
 sight Into a chronic oil spill.  Initially,
 the  character of the contamination was
 misunderstood.  The original  concept of
 a floating layer of oil that  could be
 handled easily gave way to the realization
 that the contamination had not remained as
 a water Insoluble oil but had been trans-
 formed to soluble organlcs by biological/
 chemical  activity.  Biological activity
 had  been nourished by the flreflghtlng
 foams used In the training exercises.
 These fire-fighting foams may have also
 contributed directly to solublUzIng the
 oils.  The groundwater, 25 ft below the
 surface (and only 60 ft from the
 pit), had up to 50 mg/llter total  organic
 carbon (TOC).  Infrared spectrophotometrlc
 (IR) scans Indicated this contamination
 was  1n part esters or organic acids.
 Upon emerging  from the centrifugal  pump
 (used for a pumping test), the groundwater
 frothed.5  Directly below the pit  the
water table was at 12 ft.  The hydraulic
conductivity was 5 x 10*2 cm/sec.

 Treatment Studies of the Soil

     The  overall  soil contamination had
the physical consistency of a medium
weight lube oil.   At a one-foot depth
 average oil  and grease (determined by
carbon tetrachloMde [0014] extraction)
was 13,500 mg/kg.   Deeper Into the soil,
oil and grease (OSG) values decreased.
At 5 ft, and continuing to the capillary
zone at 10 ft, OSG values were 400-800
mg/kg.  Soil samples from the aquifer
taken at 15 ft produced 5000 mg/kg OSG.
The chemical composition of the CC1.4
extract also varied with depth.  IR scans
of extracts of soil from 1 ft depth
match scans of parafflnlc oil.  Esters or
adds of oil become more evident when
approaching the water table.  Below the
water table, the oxidized oils although
present, are less prominent.  This profile
Is apparently a symptom of weathering.
The more soluble oxide forms have been
carried to the groundwater by percolating
rain water.

     The volatile contaminants also show
evidence of weathering.  In contrast to
OSG, the weathered volatlles are found
closer to the surface than to the water
table and are an order of magnitude less
abundant than OSG extracts.  A relatively
high abundance of Isoprenold compounds
(Includes many naturally occurring mater-
ials such as terpenes)  1n relation to
normal  alkanes also Indicates long term
mlcroblal degradation.6  A terpene-Uke
odor was noticed while taking soil samples
to determine the lateral  extent of contam-
ination near the surface.  Within 6
1n. of approaching the clean soil  and
at depths of 6 to 12 In.  a
"mlnty-turpentlne" smell  was reported by
the field technician.

     A part of the fire training area was
prepared so that ten mini soil washings
could be conducted simultaneously.  The
first foot of soil was not to be Included.
Therefore, ten 1 ft deep holes were dug
and the bottom of each hole was called
the "surface" of the test chamber.  Each
"chamber" was a 14-1n.  depth of soil from
the bottom of the hole down.  Surfactants
tested were:   an anlonlc sulfonated alkyl
ester (Pit 97), a polyethylene glycol  dio-
leate (Pit 110), ethoxylated alkyl phenol/
ethoxylated fatty acid blend (Pit #8), and
the contaminated groundwater (Pits 12,3,4,
5,9).  The dloleate caused soil plugging
immediately.   Compared to water, penetra-
tion rates were reduced when any surfac-
tant solutions were used.  The groundwater,
                                            387
-------
which has a low concentration of biologi-
cally produced surfactant, had the least
effect on the penetration rate.

     The dominant contamination 1n the
soil was oil and grease, up to 16,000
mg/kg, where volatlles were less than 100
mg/kg.6 04G measurements were therefore
used to determine the effectiveness of the
soil washing.  To avoid channeling during
the pilot treatment, prewash 04G measure-
ments were made on samples taken adjacent
to the chambers.  Statistically, the 04G
measurements had a coefficient of varia-
tion (CV) throughout the test area of 35%
making 1t difficult to draw conclusions
of soil washing effectiveness.  Figure 4
shows the 04G measurements after the sur-
factant wash process and the blank value.
Pit #8 was washed with the lab-developed
50/50 surfactant blend.  It 1s Interesting
to note that the 04G at 12-14 1n. has
Increased 24% above the blank and the
surface top layer 04G has decreased 50%,
Implying a transport of contaminant down-
ward during the seven days of washing with
14 pore volumes.  Keep 1n mind a CV of 35%
precludes any definitive conclusion.  The
expected reduction of contamination at the
12 1n. depth to 50% of the original level
was not realized.

Treatment Studies of the Groundwater

     Bench  scale and then pilot treatment
studies of  the  already contaminated ground-
water were  undertaken 1n anticipation of
full-scale  soil washing.  Bench-scale
studies evaluated addition of: Hme,
hydrogen peroxide, alum, ferric chloride,
and  various water treating polymers.  The
pilot  treatment was run using the EPA's
Mobile  Independent Chemical/Physical Treat-
ment Unit,  a holding  lagoon,  and an air
stripper made  by the Air Force.  Figure  5
is  a process flow diagram that also indi-
cates  sampling  points.  The  three treat-
ments  consistently used  during the opera-
tion were  lime  addition,  settling, and
  t
  J?
  '!








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SI C

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       Figure 4.   Soil washing data


volatilization.  Total  organic carbon
(TOG), volatile organic analysis (VOA),
and suspended solids (SS) tests were
used to monitor the effect of these
treatments.

     Addition of lime brought about signi-
ficant reductions in TOC.  Organics were
removed with an iron hydroxide to form a
floe.  (Interestingly, the contaminated
groundwater had up to 56 mg/llter iron
compared to background levels of 0.2 mg/
liter.) Volatlles were 95 to 98% removed
in the lagoon and air stripper.  Figure 6
Is a bar chart depicting the measured
level of TOC at four points in the process.
Figure 7 is a bar chart showing the mea-
sured levels of four volatiles at three
locations  in the process.
                                           388
-------
                                                                 minus
                   IIH


1
2
1
\\
t
*

rusi
•ii ,






M "1
ciuinti

^
              •HI
                        J
                       Figure 5.  Well field effluent treatment process and
                                  sampling points •
                                                 i
           1234
Figure 6.  Four data sets showing Level of
           TOC at the well field, clarifier
           effluent, stripper  feed, and
           stripper effluent.
TOA



                                                         'W
             i

                                                                I
                     n
              BEN
                                                                 TOL
                             EfH
                             BEN
Figure 7.   Volatiles at the well  field,
           stripper feed, and stripper
           effluent.
                                       389
-------
     In anticipation of conducting a ^ji
situ soil washing of the entire pit,
tests were run to determine control of
the natural groundwater flow beneath the
pit.  This was accomplished by a six-
member well field.  In total there have
been 13 wells Installed in the study,
7 monitoring wells and 6 withdrawal wells.
Boring logs were* kept during the drilling
operations.  Split spoon samples of the
sand and weathered sandstone were used for
chemical analysis and particle size analy-
sis.  The fines content of the directly
 below  the  pit  Is  significantly  lower than
 in  the adjacent uncontamlnated  soils -
 2 to 5% versus 10 to  15%.  Fines  content
 of  soil  8  ft below the water table,
 slightly down gradient, and In  the plume
 1s  unusually high: 28% versus 10-15%.
 The production wells  placed In  the high-
 est contamination zones have the  poorest
 fluid yield.  Paradoxically, according
 to  equlpotential lines constructed from
 water  table depths, there is a  convergence
 of  flow  passing beneath the pit
 (see Figure 8).
                                                                             902.45
      AIR
      STRIPPER
                      Figure 8.   Treatment  site showing water
                                 table equipotential lines
      This  1s  directly  1n  line  with  a  pro-
 duction well  producing water containing
 700 mg/ liter TOC  at less than 2  gallons
 per minute.   The average  for the  rest of
 the wells  is  260 mg/llter at 6 gallons per
 minute. The  design pumping rate  for  each
 well was 12 gpm.   In spite of  well  yield
 problems the  natural gradient  of  0.001
 (ft/ft) was easily reversed to create a
 radius  of  Influence of greater than 100
 ft and  a radius of capture greater  than
 the 40  ft  training pit radius.
A Follow-up Electromagnetic Survey

     An electromagnetic survey was con-
ducted over the ground surface surrounding
the training area to determine the measur-
able extent of the plume.   The decision to
do this was based on the low conductivity
of the soil, high conductivity of the
plume (600 micromohs), and the low
conductivity of the background water
(20 micromohs).  A study conducted by
the New Jersey Geological  Survey? had been
                                          390
-------
able to map an organic plume from a fire
training area In a sandy aquifer.  In the
report of that work, the fire fighting foam
AFFF was felt to be the conductive organic
that made the survey possible.  In this
work the high Iron content of the plume 1s
considered the reason for the success of
the survey.  The reason for the high Iron
content Is the reducing conditions that
exlst(ed) during biological activity at
the site.  Figure 9 Is a map of the plume
based on conductivity.
The CCl-4 extract of a soil sample taken
at 12 ft at the point marked "S" In the
figure was Identified as an oxidized oil.

     The authors wish to express their
appreciation for the cooperation, encourage-
ment and help given by a number of people
from the Wisconsin A1r National Guard and
Department of Natural Resources.  But
especially we wish to acknowledge Doug
Downey of the U.S. A1r Force for his
gentle persistence In directing the work
done at Volk Field.
                                               CONCLUSION

                                                    The mechanical  aspects  of applying
                                               a  surfactant to  soil  and  controlling an
                                               underlying  unconfined acqulfer to capture
                                               the  wash solution  have been  demonstrated at
                                               a  site  of opportunity.  Issues that remain
                                               to be addressed  are  treatment, If necessary,
                                               of the  used surfactant solutions. Isolation
                                               of the  containment from the  surfactant and
                                               developing  a method  to recycle the surfac-
                                               tant.
     Figure  9.   Electromagnetic  Survey
                                            391
-------
REFERENCES

1. Texas Research, Institute, Inc.
   Underground Movement of Gasoline on
Undergr
Ground*
        Jwater and Enhanced Recovery by
   Surfactants. September 14, 1979
   American Petroleum Institute, 2101 L
   Street, NW. Washington, DC.

2. EIHs, M. D., J. R. Payne, Treatment
   of Contaminated Soils with Aqueous
   Surfactants (Interim Report)
   September 6, 1985 to EPA-HWERL.
   Releases Control Branch, Edison, NJ.

3. Waller, M. J., R. Singh, J. A. Bloom.
   Retrofit of a Chemical  Delivery Unit
   for In S1tu Waste Clean-up, EarthTech,
   Inc.  January 7, 1983.
   Releases Control Branch, Edison, NJ.

4. Hazardous Materials Technical  Center
   Installation Restoration Program
   Records Search prepared for 8204th
   Field Training Site, August 1984
   available N.T.I.S.

5. Nash, J. H., Pilot Scale Soils Washing
   and Treatment~at Volk Field ANG, Camp
   Douglas WI, In preparation.

6. McNabb, G. n., et. al.   Chemical
   Countermeasures Application at Volk
   Field Site of Opportunity,
   September 19, 1985 to EPA-HWERL.
   Releases Control Branch, Edison, NJ.

7. Andres, K. G. and R. Crance,  Use of the
   Electrical Resistivity  Technique to
   Delineate a Hydrocarbon Spill  In th~e
   Coastal Plain Deposits  of New Jersey.
   Proceedings;   Petroleum Hydrocarbons
   and Organic-Chemicals In Ground Water,
   November 5-7, 1984 available  National
   Water Well Association. Dublin, OH.
                                         392
-------
               DRAFT
     SUMMARY OF THE WORKSHOP ON
         EXTRACTIVE TREATMENT
           OF EXCAVATED SOIL

           DECEMBER 1-2, 1988
             Contract 68-03-3255
       Foster Wheeler Enviresponse, Inc.
             Edison, NJ  08837
              Project Officer
              Mary K. Stinson
         Technology Evaluation Staff
           Releases Control Branch
     Risk Reduction Engineering Laboratory
             Edison, NJ  08837
RISK REDUCTION ENGINEERING LABORATORY
 OFFICE OF RESEARCH AND DEVELOPMENT
 U.S. ENVIRONMENTAL PROTECTION AGENCY
          CINCINNATI, OH  45268
                  393
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394
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                          DISCLAIMER AND PEER REVIEW NOTICE


     The  Information In this document has been funded wholly or In part  by the
  United  States Environmental Protection Agency under Contract No. 68-03-3255 to
  Foster  Wheeler Envtresponse, Incorporated.  It has been subject to the Agency's
  peer  and administrative review, and It has been approved for publication as an
  EPA document.  Mention of trade names or commercial products does not
  constitute endorsement or recommendation for use.
OJ
                                           it
                                    FOREWORD

   Today's rapidly developing and changing technologies and Industrial products
and practices frequently carry with them the Increased generation of materials
that If Improperly dealt with can threaten both public health and the
environment.  The U.S. Environmental Protection Agency is charged by Congress
with protecting the nation's land, air,  and water resources.   Under a mandate
of national environmental laws, the agency strives to formulate and Implement
actions leading to a compatible balance  between human activities and the
ability of natural systems to support and nurture life.  These laws direct the
EPA to perform research to define our environmental problems, measure the
Impacts, and search for solutions.

   The Risk Reduction Engineering Laboratory 1s responsible for planning.
Implementing, and managing research, development, and demonstration programs to
provide an authoritative defensible engineering foundation In support of the
policies, programs, and regulations of the EPA with respect to drinking water.
wastewater, pesticides, toxic substances, solid and hazardous wastes, and
Superfund-related activities.  This publication Is one of the products of that
research and provides a vital communication link between the researcher and the
user community.

   This report summarizes technologies discussed at a workshop held at the U.S.
EPA Technical Information Exchange In Edison, NJ.  These treatment methods have
potential for cleaning excavated soils by use of extraction agents.  Areas for
further research and development are Identified to aid In developing potential
treatment technologies for volume reduction of Superfund soils prior to land
disposal.

   For further Information, please contact the Superfund Technology
Demonstration Division of the Risk Reduction Engineering Laboratory.
                                                                                                                                             E. Timothy Oppelt, Acting Director
                                                                                                                                             Risk Reduction Engineering  Laboratory
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uo
VD
                                    ABSTRACT

   The U.S. EPA sponsored a workshop on December 1-2,  1988  to  review methods
for extractive treatment of excavated soil.   Sessions  were  held on
characterization of contaminated sites, techniques  used for metals extraction,
techniques for radioactive materials extraction,  and techniques for organic
contaminant extraction.

   Lead has been extracted successfully from soil using ethylenedtamlnetetra-
acetlc acid (EDTA) In an electronembrane process.   Radlonuclldes volume
reduction chemical extraction (VRCE) methods have been applied.  Extraction of
radlonuclldes from soil  has been accomplished using water or salt solutions,
but extraction efficiency has been limited.

   Numerous technologies for organtcs removal  have  been developed.  RCC's
B.E.S.T. process has shown good results for removing oily wastes from  soil.
The MTA and Btotrol processes have shown promise on a  pilot scale.  Harbauer
has been successful In treating finer particle soils above  63  urn and  Is
studying decontamination of soils as fine as 10 urn. A humlc acid extraction
process has shown limited results in removing organlcs from soil.

   Many sites 1n the U.S. contain contaminated soils that presumably could be
treated by one or more existing technologies.   Some of the  technologies  will be
in full-scale operation In the near future,  having  been demonstrated on  a  pilot
scale.  However, few of them have successfully removed contaminants from soil
clay fractions (<10 urn).  Further study Is required.
                                                                                                                                       CONTENTS
Foreword	     111
Abstract	      1v
Figures	     vll
Tables	    vlil
Acknowledgments 	      1x

     1.   Introduction and Summary   	       1
               Introduction  	       1
               Summary of Results 	       1
     2.   Conclusions and Recommendations  	      11
               Conclusions	      II
               Recommendations   	      11
     3.   Introductory Remarks and Soil Washing Technology Overview .  .      13
               Introductory  Remarks  	      13
               State-of-the-Art  of Soil Washing Technology	      14
               Assessment of International  Technologies for
                  Superfund Application  	      17
     4.   Technical  Session  - Site Characterization 	      23
               Hoc,  The  Unconstant Constant 	      23
               Case  Histories for Underground Storage Tanks 	      25
               Characterization  of RCRA/CERCIA Sites With
                  Contaminated Soil   	      25
               Site  Characterization Technical Session:
                  Selected Questions  and Answers  	      26
      5.   Technical  Session  - Techniques/Experiences for Metal
              Extraction	      30
               Hydromtallurglcal Treatment of Soil	      30
               Lead  Extraction  from  Excavated Soil  	      32
                Innovative Electromembrant Process for Recovery of Lead
                  from Contaminated Soils   	      34
               Metal Extraction Technical Session:  Selected
                  Questions  and  Answers  	      36
      6.   Technical  Session  - Techniques/Experiences for Radioactive
             Materials Extraction  	      38
               Soil  Washing  and Chemical  Extraction of
                  Radlonuclldes   	      38
               Ra (226)  Removal  from a Contaminated Soil  	      39
               Remediation  of Formerly Utilized  Sites Remedial
                  Action Project (FUSRAP)  Sites  	      43
                Radioactive  Materials Extraction  Technical Session:
                  Selected Questions  and Answers  	      44
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                                  CONTENTS (continued)
                                                                                                                                             FIGURES
         7.    Technical  Session -  Techniques/Experiences  for Organlcs
         8-
VD
-J  References
  Extraction
     Btotrol Soil  Washing Systems for Removal  of
       Organic Contamination at Wood Treating  Sites .
     Experience Gained with a Soil-Decontamination
       System In Berlin 	
     Organlcs Removal by Froth Flotation as a  Soil
       Washing Process  	
     The B.E.S.T.  Sludge Treatment Process  	
     Surfactants for Washing of Petroleum from Soil .
     EPA Soil Washing Technology Overview - Good
       Economic Sense 	
     Organic Extraction Technical Session:  Selected
       Questions and Answers  	
Summary and Roundtable Discussion Period	
    Appendices

         A.
         B.
Program Agenda  .
List of Attendees
46

46

47

52
54
62

62

73
74

75
78
81
Number
1
2
3
4
5
6
7
Distribution of CERCLA soil subcategorles 	
Simplified process flow diagram of overall soil
washing process 	
Flow schematic of the Harbauer soil washing process 	
Particle size distribution for Harbauer's soil
washing process 	
Generalized flowsheet for soil wash plant 	
B.E.S.T.™ process flow diagram 	
Results of soil washing with water or humic acid solution . . .
Page
27
35
51
53
56
61
63
                                            v<
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TA8US                                                                                       ACKNOWLEDGMENTS






                                                                                               To Be Added
Number
1
2

3
4

5
6
00 7
8
9

10

11

12
13
14
15
16
17 •

Soil Washing Installations Visited by Alliance/EPA Field Team.
Results of Soil Cleanings Performed by Heljmans
Mllleutechnlek B.V 	
Summary of Soil Washing Performance for Other Systems 	
Typical Superfund Soil and Sludge Contamination Levels
for Selected Contaminants 	
Chemical Analysis of Test Soils 	
Add Leaching of The Soil 	
Chloride Leaching With Low Acidity 	
Leaching With Chloride Salts and EDTA 	
Comparison of Pentachlorophenol In Feed and Clean
Product BSTS Pilot Study 	
Performance of The Harbauer Soil Washing System on
Sandy Soil 	
Performance of the Harbauer Soil Washing System on
Soils With Light Clay Content 	
Soil Washing Results for Volattles 	
Soil Washing Results for Semlvolatlles 	
Soil Washing Results for Fuel Products 	
Results of Soil Washing With Water or Humlc Acid Solution . . .
HaxImuM Debris Size/Technology 	
Rank-Order Summary of Treatment Technology Ons Ite 	
Page
18

21
22

28
36
40
42
42

48

54

54
57
57
58
64
67
70
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                                     SECTION 1


                              INTRODUCTION AND SUMMARY
  INTRODUCTION

     This report presents a sumary of presentations and discussions on
  extractive treitnent of excavated soil held at the US EPA Technical Information
  Exchange (TIX) Conference Center, Rarltan Depot, Edison, NJ.   The two-day
  workshop entitled "Workshop on Extractive Treatment of Excavated Soil* Mas held
  on December 1-2, 1988.  The program was sponsored by EPA's Office of Research
  and Development, Risk Reduction Engineering Laboratory, Superfund Technology
  Demonstration Division, Releases Control Branch (RCB).

     The program  agenda began with introductory remarks by Mr. Frank Freestone
  (EPA/RCB)  followed  by general presentations on soil washing state-of-the-art
  and  international soil washing applications.  This Introductory session was
  followed by four technical  sessions on  (1) site characterization;  (2)
^techniques for/experiences  with metals  extraction; (3) techniques  for
oexperlences with radioactive materials  extraction; and  (4) techniques for
^experiences with organlcs extraction.   The workshop  finished with  a sumnary  and
  roundtable discussion moderated  by Hr.  Freestone.  A complete program agenda is
  given In Appendix  A.   In  addition, a  list of  program participant's name,
  affiliation,  address,  and phone  number  is given  In Appendix B.

      This report Is divided Into  eight sections:   (1) introduction  and summary;
  (2) conclusions and recommendations;  (3) the  Introductory session; (4)  the four
  technical sessions; and (5) the  roundtable  summary and discussion.  Each
  technical section concludes with pertinent  questions, comments,  and  other
  salient remarks on previously presented topics covered during that session's
  questIon-and-answer period.

       Presentation summaries for this report were prepared using notes taken
  during the workshop, copies of the presentations, tape recordings of the
  workshop  proceedings, and/or company literature.  When possible, relevant
  material  from the  furnished presentations was excerpted directly.

   SUMMARY OF RESULTS

       The  following  discussion briefly summarizes the  results of the
   presentations given at the workshop.   More detailed  discussions are found 1n
   Sections  3  through 8 of  this report.

   Introductory Remarks  and  Soil Washing  Technology  Overview

       The Introductory  session  served  to outline  the  focus of  the two-day
   workshop and Included  two  general presentations  on  soil  washing technology.   In
   his Introductory remarks,  Mr. Freestone characterized the principal goal  of the
   EPA's soil cleaning program as  the  desire  to influence  and encourage connercial
   development and use of viable systems  for  treatment of  excavated  contaminated
   soils from uncontrolled site remediation activities.  Mr. Freestone  then
 Identified five major program areas currently being pursued:  (1) problem
 characterization; (2) evaluation of state-of-the-art technologies; (3)
 development and demonstration of promising systems; (4) technology-transfer;
 and (5) coordination with other organizations outside the EPA.  Hr. Freestone
 then discussed current and future efforts being made by EPA, other government
 agencies, and non-government groups In these program areas.

     The presentation by Dr. Ramjee Raghavan discussed a recent report prepared
 for EPA on state-of-the-art soil washing technology1.  This study developed a
 state-of-the-art review of soil cleaning technologies and their applicability
 to Superfund sites In the United States.  Research objectives Included
 summarizing Superfund site soil and contamination characteristics, soil
 cleaning technologies, principles of operation, process parameters, and the
 technical feasibility of soil  washing In the United States.  Three generic
 types of extractive treatments were identified: (1) water washing augmented
 with a basic or surfactant agent or with an acidic or chelating agent to remove
 organlcs and heavy metals, respectively; (2) organic solvent washing to remove
 hydrophoblc organlcs and PCBs; and (3)  air or steam stripping to remove
 volatile organlcs.  Several pilot and full scale technologies employing these
 extractive technologies were described  and discussed.   In addition, specific
 process parameters influencing the effectiveness of each soil  washing
 extraction technique were described.

     Mr.  Thomas  Phelffer of the EPA Office of Program Management  and Technology
 summarized the  results of a nine-month  EPA study on international  technologies
 applicable to hazardous waste.2  This study reviewed five full-scale soil
 washing  technologies in Holland and FR6.   A key similarity among all  of the
 units  was  that  they  operate on the principle that most  of the  contaminants  are
 sorbed to  the fine materials (<63  urn) and that  segregation of  these materials
 from the other  size  fractions  "cleans*  the soil.   Some  of the  units (I.e.,  the
 Heljmans unit)  employed very simple particle separation and wash water
 treatment  technologies,  while  others  (Harbauer  and  Oil  CREP) employed  more
 sophisticated extractants  and  cleaning  agents.  A major consideration  of all
 washing  techniques Is  the  fact  that  as  particle reject  size cutoff decreases,
 so does  sludgt  residue generation.  Cleaning  efficiency tends  to decrease with
 decreasing particle  size.

    Most of the soil washing companies  noted  that their practical  upper limit
 of fines (<63 urn) was  20X  to 30* in  the  sol)  to be  cleaned.  Because the
 proportion of fines  present  Increases the generation of sludge,  treatment costs
 tend to  increase for finer grained  soils.  The Harbauer technology shows an
 advantage of potentially generating less  sludgt; however,  the  additional costs
 of wash water treatment employed for that technology make  It slightly  more
 expensive than  the other soil washing technologies  reviewed.

 Site Characterization

    the  first presentation in this technical session was a paper by Dr.  Warren
 Lyman on "Koc, The Unconstant Constant".3  Dr. Lyman's presentation focused
on the value of the organic carbon sorptton equilibria relationship:
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o
o
                             K     ug  adsorbed/9 organic carbon
                              oc •  	
                                         ug/ml  solution
      In estlnatlng the partitioning  of chemical constituents In soils.  Or. Lyman
      cited the correlation KQC • KO/FOC where:
           Koc • organic carbon sorptlon  constant

           KD  • measured sorptlon constant
           'oc
                 fraction organic carbon (0 <  Foc  <  t)
    Dr. Lyman then Identified a series  of anomalies  and circumstances  In which
the relationship was less than exact.   Dr.  Lyman noted that the relationship
holds for neutral organic solutes In equilibrium with soils containing greater
than 0.1 organic carbon.  Specific problems Identified by Dr. Lyman  Included:
(1) measurement protocols; (2) variability In  predictive correlations; (3)
"solids concentration effect*, due mostly to nonsettleable particles;  (4) the
variable nature of organic matter in soils and sediments; (5) the effect of
(truly) dissolved organic matter; (6)  anomalous temperature effects;  (7)
unusual pH effects (acids, bases); (8)  the effects of salinity or ionic
strength; (9) kinetic limitations; and (10) chemical class differences.

    Rich Griffiths of EPA/RCB gave a presentation  on the capabilities of and
Information contained within a computer data bast  system written to  access case
history files/  Information entered Into the  program was generated  by the
Releases Control Branch or acquired from the Superfund Technology Demonstration
Division and covers such areas as landfill remedial  action, removal  action,  and
underground storage tank corrective action.  The  program presently utilizes  27
search criteria  enabling the user to search case  history files  for various
Information.  Some examples of available search criteria are:   treatment
technology, site geology and hydrology, chemicals Involved, volume affected,
and  sources of contamination.  No soil washing technology case  studies are
currently contained  in  this  file.

     Pat  Esposlto of Bruck Hartman and Esposlto, Inc. summarized available
Information on RCRA  and CERCLA sites with contaminated  soil.5   Of  151 rods
reviewed for soil data  at Superfund sites, 60 had no Information on  soil  type,
30 were  classified as sandy,  15  were primarily clay soil,  and  45 were •  mixture
of sandy-clay  soil.  From this data, 75 ROOs,  or half of  the  sites,  have sandy
or sandy-clay  soils  amenable  to  soil washing.   Two-thirds  to  three-quarters  of
the  sites needing soil  treatment are predicted to be in  the eastern  United
States.   In a  CERCLA soil study,  of 116 ROOs reviewed,  a  soil  description was
found for 95 ROOs.   Fifteen  percent of these ROOs contained sandy  soil.   No
information was  found on  soil  type or soil contamination  at RCRA sites.

     In 1987, this Information was used as the basis for development  of a
surrogate Superfund  soil  for  research purposes.  The surrogate soil, or
synthetic soil matrix (SSH) was  prepared by blending prescribed amounts  of
clay, sand, gravel,  silt, and  topsoll together In two 15,000-lb batches  using a
                                               3
 conventional  concrete mixer.   A select group of organic and inorganic
 contaminants  known to frequently occur at CERCLA sites was then added to the
 soil  through  a series of pilot-scale blending operations.   This synthetic soil
 has been used as a test matrix for evaluating the treatment efficiency of
 several  different technologies Including soil washing/volume reduction.  The
 development,  characterization, and preparation/manufacture of this synthetic
 soil  was also discussed.

 Metal  Extraction

     This technical session began with a presentation by William Schmidt of the
 U.S.  Bureau of Nines.   Recently, the Bureau began to explore the matter of the
 application of Its metallurgical technologies to the problems of remediation of
 contaminated  Superfund sites."  Mr.  Schmidt discussed a few examples to
 demonstrate the kinds of treatment techniques under investigation.  The first
 two were from ongoing studies  of contamination associated  with mining sites
 involving arsenic contamination.  The last example was directly related to work
 with  EPA on Superfund sites.   Mr.  Schmidt discussed analytical results and
 mineralogy at each site,  leaching treatment test results,  and leachate
 treatment methods using Ion exchange/adsorption to a ferric oxide/ferric
 hydroxide matrix.   According to Mr.  Schmidt,  the Bureau has found that its
 experience In metallurgical technology has allowed it to successfully treat
 inorganic wastes from both listed and unlisted sites.   They believe that these
 techniques can be applied to a wide  range of Inorganic treatment needs at costs
 that  are lower than,  or at least competitive with,  the alternatives.

    Andre Zownir of U.S.  EPA's Environmental  Response Team gave a presentation
 on  soil  washing applled.at the Lee's Farm site In Woodville,  W1s., a former
 battery  recycling site.'   The  objective of this study was  to  explore the
 feasibility of soil washing with EOTA to remove lead contamination from
 contaminated  soils at  the Lee's Farm site.   Contaminated soil  from Lee's Farm
 averaged 50,280 ug/g  total  lead and  65 mg/L Extraction Procedure Toxlclty (EP
 Tox)  lead.

    Soil  wash)no of the coarse fraction with  20 wtl EDTA reduced lead 9SX to
 97X with a total  lead  concentration  ranging from 656 to 3411  ug/g remaining In
 the treated soil.   Soil  loading (the percentage of  soil  In the extraction
 mixture)  of 25X and 45X were used, and the  Increase did not significantly
 reduce extraction  efficiency.   The EOTA polish  rinse,  following the EOTA
 extraction step,  adversely affected  treatment compared with an EOTA-free
 (water)  rinse  by Increasing EP Tox lead and not reducing total  lead In the
 treated  soil.   The 45-nln extraction  step was shortened  to 15  mln for
 subsequent experiments  because  the lead uptake  by EOTA was  occurring more
 rapidly  then expected.  Sequential extractions, where  an extraction solution
was repeatedly exposed  to contaminated  soil, were performed to replicate field
conditions.  These experiments  found that the EDTA  solution still  reduced lead
significantly after 11  sequential extractions.

    A presentation by Radha Krtshnan of PEI Associates,  Inc. discussed an
electromembrane process for removal and recovery of.lead from contaminated
soils using ethylenedtamlnetetraacetlc acid (EDTA).8  Soil  treatablllty
testing was conducted to determine the optimum conditions for soil-EDTA
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  reaction to:  (1) maximize lead chelatlon; (2) minimize EDTA consumption; and
  (3) minimize reaction time.  Results showed that Increased lead was plated with
  Increasing tine 1n all cases.  Extremely high lead recoveries and current
  efficiencies were observed for the 3* and IX lead solutions during the
  experimental time period.  Lead recoveries were below 40X at the 0.2X lead
  level for the experimental time period.  Greater time periods should result In
  higher lead removal efficiencies for the low lead solutions.  However, lead
  removal efficiencies approached 90% for the IX and 3X lead solutions.

      According to Or. Krishnan, this bench-scale research has shown the
  feasibility of the two essential process steps of an Innovative soil-washing
  process:  chelatlon and electro-deposition.  A long-term pilot-scale
  demonstration at several actual sites is necessary to develop the data required
  for commercialization.

  Radlonucllde Extraction

      B111 Richardson of EPA's Office of Radiation Programs presented a
  discussion of the radlonucl ides volume reduction chemical extraction (VRCE)
  project located at a Montgomery, Ala. facility.9  The VRCE project Included
  three stages:  (1) mineralogy; (2) treatment (soil  washing and chemical
  extraction); and (3) Implementation.  Radioactive soils used for
^experimentation were taken from the Glen Ridge/Montclalr, N.J. areas.  Soil
ofrora both areas were contaminated with Ra(226) and Th(230) years ago during a
H-1 radium extraction process.  The primary contaminant was
      Soil samples taken from the Glen Ridge and Montclair areas underwent
  characterization studies to evaluate soil  sizing and distribution of
  radlonuclldes.  Soils high In activity were chosen for analytical work.

      Initial washing studies using slightly acidic salt solutions  (NaCl,  KC1,
  CaCl, EDTA) showed filtrates with high levels of soluble radium.   In an  effort
  to remediate the soil without solubillzing any more radlonuclldes,  the use of
  salt solutions was discontinued and water was substituted.   Even  though
  one-step washing of the samples showed relatively modest removal  percentages,
  most of the specific radioactive levels were not close to the allowable
  standard of 15 pCI/g.

      A final study was performed to determine the effect an Increased shaker
  rate had on removal percentages.  The rate was Increased from 100 rpm to 350
  rpm on three sieve-size samples.  Thirty-five percent of the Montclair soil was
  recovered at 350 rpm.  The weighted average radioactive level  of  the soil  was
  approximately 13 pCI/g.  The specific levels of the washwater were less  than  25
  pCi/L.

      Or. Haque from the Canadian Center for Mineral  and Energy Technology
  (C AHMET) presented a paper on Ra(226) removal  from soil.10   A series of  leach
  tests was conducted on the sol), utilizing water,  hydrochloric acid,  nitric
  acid, chloride salt solutions, and EOTA extracting solutions.   According to Dr.
  Haque. the removal  of radium from this soil  by chemical  methods will  require
  further work, as none of the leachlngs were very effective.   The  recovery  or
  removal of Ra(226)  from leach liquor Is still  an unresolved  problem.
    Mr. R. Atkln of the U.S. Department of Energy.spoke about the Formerly
Utilized Sites Remedial Action Project (FUSRAP).11  Established in  1974.  one
of FUSRAP's purposes has been to restore sites for the unrestricted use by  the
owner.  Until 1984, DOE followed its own protocols and procedures for disposal
of uranium-contaminated soil residues.  As a result of SARA, DOE is now
following CERCLA protocol and has just begun evaluating treatment
technologies.  Formally, the approach had been to find a permanent disposal
site for the uranium-contaminated residues.  The search was primarily focused
in Oregon, but DOE has had difficulties In accomplishing the task and as  such.
Is now looking toward treatment technologies.

    FUSRAP primarily Includes sites formerly utilized during the Manhattan
project by the Manhattan Engineering District.  Under this project, uranium ore
was placed 1n temporary storage, mostly in the northeast and midwest.  The  ore
was assayed, sampled, and sent for processing at six locations.  Sites
associated with uranium milling are Incorporated within UMTRAP  (Uranium Mill
Tailings Remedial Action Project) while most of the other sites fall under  the
FUSRAP Program.  After processing, samples went to two different places.
Uranium oxides were sent to facilities as a part of the plutonlum operation,
while uranium hexafluorldes were taken primarily to Oakrldge, Tenn. for
enrichment.

    The majority of FUSRAP  sites are located In New York and New Jersey,  with
others In Missouri.  Each state has a site manager.  Permanent  disposal  Is
being sought In each of these states for the contaminated residues.  As  a
result of a congressional mandate, five sites were added to the FUSRAP Program
that were not formerly utilized by the Manhattan project, but did contain
similar contaminated materials.  The total number of FUSRAP sites became  29.
Two more sites are about to be added.

    Sites were chosen by DOE headquarters In Washington and turned  over  to  the
field office in Oakrldge.   Following characterization and preliminary
engineering, the NEEPA/CERCLA remedial action process Is begun.  Decontaminated
materials are presently In  interim storage at the site of origin.   Ideally, DOE
would like to store the materials at a permanent disposal site, but no
permanent site currently exists.  Three DOE sites in New Jersey have been
remediated: Middlesex Sampling Plant, Maywood, and Wayne.  These sites have
30.000, 35,000, and 50,000  yd3 of decontaminated residue  in vicinity property
Interim storage, respectively.

Organic*  Extraction

    Mr. Steve Vallne of Blotrol  Inc. gave a presentation on the Blotrol  Soils
Treatment Systeti (BSTS).1Z  The BSTS system is a unique and proprietary
physical/Microbiological treatment technology for onsite remediation of
contaminated soils.  The BSTS technology uses soil scrubbing as a volume
reduction step In  a multtcomponent soil decontamination system.   It Is  ideal
for soils that require excavation, and/or where other technologies  will  not
produce timely results.  Large-scale BSTS units will have throughputs of  10
ton/h and will operate on a 24-hour day, 7-day/week basis.
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      BSTS has the broadest experience base on a variety of  contaminated  media,
  among the* wood-treating wastes Including penta-creosote components.  Other
  potential contaminants that are targets to be treated  by the  BSTS  include
  chlorinated hydrocarbons such as TCE, PCE, and TCA,  In addition  to PAHs,  coal
  tar residues, and organic pesticides.  Underground storage tank  contaminants
  such as fuels and solvents are attractive candidates for biological  treatment
  using the BSTS units.

      A major application of the BSTS technology Is In volume reduction for a
  large-scale treatment project where the principal treatment strategy Is for
  on-slte Incineration.  By using volume reduction prior to  Incineration, the
  total cost of treatment Is significantly reduced.  In general, BSTS process
  cost totals generally fall within the range of $75 to S125/ton depending upon
  volume, soil type, and contaminant concentration.

      Ms. Hargarett Nells, representing Harbauer GmbH and Company  AG, discussed
  the operation of the Uarbauer extractive soil washing system  at  the Plnsch Oil
  site since July 1987.z'13  The primary pollutant groups found at the Plnsch
  site In both soil and ground water were:  mineral oil, halogenated
  hydrocarbons, polycyclic aromatic hydrocarbons, polychlorlnated  blphenyls,
  aromatic hydrocarbons, and phenols.  In addition, polychlorlnated
  dlbenzodtoxlne and dibenzofuran were found.
-f
°    The Harbauer soil washing system Is currently considered  to  be among the
  best soil washers developed  In the FRG.  The heart of the unit 4s a low-
  frequency vibration  step used to  improve cleaning by mechanical  action.
  Harbauer claims that a combination of low-frequency vibration and other washing
  techniques  Is effective at desorblng contaminants from the smaller particles,
  allowing Harbauer to separate out a  larger proportion of reusable soil.
  Harbauer separates soil particles from  15 urn and greater for a recovery rate of
  95%.

      All  the  contaminated effluents  from soil washing are pumped  to the ground
  water  treatment system on  site.   The ground water treatment system has five
  main operations:  dissolved  air  flotation (OAF), countercurrent  stripping, air
   stripping,  sand filtration,  and  adsorption  (activated carbon and resin).  The
  groundwater treatment facility  Is full  scale,  treating 360 m-yh  (1,584 gpm).

      Although the Harbauer  system Is  considered semtbatch, because only some of
   the'steps  are run  In batches,  It has a  throughput of 20 to 40 ton/h (22 to 44
   ton/h).  The unit cost  Is  $250  DH/ton  of  soil  (about $136/ton),  not Including
   the cost of residue  disposal.   Capital  costs  for the same facility today would
   be In  the  range of 7 to  10 million  ON  ($4.3  to $6.1 million).  Operational
  costs  and  requirements  for both the Initial  separation and the subsequent
   separation'and dewaterlng  of sludge Increase disproportionately with decreasing
   particle size.  When Harbauer began the project, the  limit was 63 urn.  They are
   now Investigating, under a joint research project with the Ministry for
   Research and Technology  and  the land Berlin, whether  It 1s feasible,
   technically and economically,  to achieve  an even finer separation  In the range
   of 10  urn.

       HP.  Paul Trost of MTA Remedial  Resources  Inc. gave a  presentation  on the
 HTA Soil Hash process  involving  the use  of  froth  flotation,  a commonly used ore
 beneftclatlon technique.1*   In the MTA Soil Hash  unit,  the incoming
 contaminated soil Is preconditioned with a  combination  of surfactants  and
 alkaline agents to aid In the removal and separation  of the  organic
 contaminants from the clay and sand.  The soil/water  slurry,  generally being
 approximately 30 wtX solids, Is  then pumped as  a  slurry to the froth flotation
 cells.  These cells are equipped with paddle wheels to  skim  off the froth that
 forms at the top of the cell.  Depending upon soil mineralogy, the  froth will
 contain 5 wtX to 10 wtX of the original  soil feedstock.   The clean  soil  passes
 from one cell to the next as an  underflow:  retention  time In each cell  is
 regulated by adjustment of the weir gates dividing one  cell  from the other.
 Typically, retention times from  5 to 30  min are necessary to achieve the
 desired cleanup.  The clean soil, after  exiting as a  slurry  from the cells.  Is •
 then piped over to a standard solid/liquid  separation system.   The  water can be
 recycled back Into the process,  thereby  minimizing water treatment.  Final
 water cleanup can be achieved by using carbon adsorption or  other suitable
 means.

     Process flow rates have been engineered for Soil  Wash units  as  small  as  5
 ton/d to as large as 860 ton/d.  Both operating and capital cost have been
 determined on a number of private and Superfund projects  to a  +10%  level.
 Depending on the nature of the contaminant, mineralogy of the  sample,  volume of
 the material, the degree of cleanup,  and  the rate of  cleanup,  the costs will
 vary from $50 to $180/ton.   Typically,  a  50,000-ton cleanup would cost
 approximately $85 to JlOO/ton assuming a  Level  C protection.    This cost
 Includes operating and capital  costs,  disposal  of the froth containing the
 contaminant,  excavation,  backfill,  and  health and safety.  MTA RRI  has
 evaluated Soil  Wash  systems  varying in  size from 5 to 860 ton/d, and is
 currently In  the process  of  designing  and constructing a 50 ton/d mobile
 demonstration unit.  Availability Is expected In 1989.

    Nr.  Douglas  Austin  of Resource  Conservation-Company  (RCC) cave  a
 presentation  on  the  RCC B.E.S.T.'"  process.15'16  The  B.E.S.T.'" process
 mixes  a  refrigerated anine solvent  with oily sludges.  The solvent  Immediately
 liquifies the sludge and  turns  the  mixture Into  a  homogenous  solution.   Since
 the temperature  Is kept below the solubility limit of  the solvent, solids are
 no longer bonded by  the oil/water emulsion that  was part of the original  sludge
 and are  released from the solution.  Once the solids are removed, the
 temperature of the liquid fraction, which contains the oil, water, and  solvent.
 Is heated above the solubility point for  the solvent,  and the  water  separates
 from the oil  and solvent.  The last step  in  the  process  is to  remove the
 solvent fro*  the oil using classical distillation.

    The distillation overheads are stripped  off  as an  azeotrope containing 10
wtX water and 90 wtX solvent.  These overheads are sent,  along  with  the solvent
vapors from the dryer, to a condenser from which the condensate Is sent to a
decanter.  In the decanter, the bottom water fraction  is  removed  and recycled
through the water stripper; what  Is left  Is  pure recovered solvent.  The
recovered solvent Is refrigerated and returned to  the  beginning of the process,
and the cycle Is repeated.

    B.E.S.T.™ process economics vary widely from one  application to
-------
  another.  Variables  Include  feed composition  (and variability), product
  requirements, utility costs  and availability,  feed flow rate and  volume  (If not
  a continuous  flow),  fixed costs (Installation  and demobilization),  etc.   The
  total costs quoted by RCC range from a low of  SSO/ton  (owner-operated  on
  continuously  generated,  large volume, low organic sludge  In a  large.  Integrated
  Industrial facility), to a high of $ISO/ton (RCC-owned and operated on a
  stand-alone basis at a small, remote Superfund site).
  the
Dr. A. Abdul of General Motors Research Laboratory gave a presentation
use of humlc acid leaching for organic contaminants.17  The contaminan
           on
contaminants
  studied were  aromatic hydrocarbons:  benzene, toluene, p-xylene,
  3-ethyltoluene,  sec-butylbenzene, and  1,2,4,5-tetramethylbenzene.

     According to Or. Abdul, washing with the humtc acid solution enhanced  the
  migration of  the contaminant  from aquifer material to solution after a number
  of washings for  a  few of  the  contaminants.  The humlc acid  solution did not
  help contaminant removal  of benzene or toluene, yet washing ethylbenzene with
  the solution  showed  a 40X Improvement  over washing with water alone.

     From this study, washing  with a 27 ppra humlc acid solution was found to
  improve the removal  of  some organic compounds from aquifer  material.
  Additional research  is  needed (n such  areas as the hydrophobictty of the humlc
j^acld,  the pH  of  the  pore  water, the aquifer organic carbon, and the Impact of
othe humlc acid on  the environment.
JO
     Mr. Rick  Traver  of  EPA Releases Control Branch gave a presentation focusing
  on four papers describing current efforts by the U.S. EPA on soil washing
  technologies. These papers were:   (1) Mobile System for Extracting Spilled
  Hazardous Materials  from  Excavated  Soils; (2) Investigation of Feedstock
  Preparation and  Handling  for  Mobile On-stte Treatment Technologies; (3) Results
  of Treatment  Evaluations  of Contaminated Soil; and (4) Superfund Standard
  Analytical Reference Matrix Preparation and Results of Physical Soils Washing
  Experiments.

     The first paper  discussed EPA/RCB's nftrtx soil washer. Its design,
  components, applications  and  limitations.    Various conclusions drawn from
  work done with the soil washer were presented.  The second  paper discussed the
  Importance of feedstock preparation and handling for mobile treatment units,
  making recommendations  on how to classify and segregate materials."  The
  third  paper discussed the material  used In the development  and formulation of
  Synthetic Analytical Reference Matrix  (SARM) surrogate soil.20

      In the third study, SARM  surrogate soil containing a wide range of chemical
  contaminants  typically  occurring at Superfund sites was prepared and subjected
  to bench- o'r  pilot-scale  performance evaluations using the  following treatment
  technologies: (1) physical separation/volume reduction (soil washing); (2)
  chemical treatment (specifically, K-PEG); (3) thermal desorptlon; (4)
  incineration; and  (5) stabilization/fixation.  This report  covered the
  formulation and  development of the  surrogate soil; it also  highlighted the
  results of the five  treatment evaluations.

     The fourth report covers  development of a surrogate soil and experimental
                                                                                                                         into  Solution than  In mobilizing the metals.
                                                                                                                                               10
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                                    SECTION  2
                         CONCLUSIONS AND RECOMMENDATIONS
CONCLUSIONS
        The seminar was a reasonably concise forum for disseminating information on
    soil washing state of the art and soliciting Ideas from an Informed audience.
    Conference size was Intentionally kept small to avoid the loss of Interaction
    associated with larger gatherings.

        The following general conclusions were drawn from the technical portion of
    the  seminar:

    o    Although many sites contain substantial amounts of clay materials,  it is
        likely that many sites across the United States contain soils that would
        potentially be amenable to soil washing/extraction technologies.

    o    Soil washing technologies are well developed In Europe on a high-throughput
        basis.

_t  o    Several soil washing  technologies have been successfully demonstrated in
o      the United States on  a pilot scale.  Full-scale operations will be
t=      available within 6 months.

    o    Recovery of EOTA and  lead from soil washing processes was found to be
        feasible through electromembrane methods.

    o    Water extraction of radionuclldes is best accomplished using water or salt
        solutions.  Extraction efficiencies with radionucltdes were limited and
        require additional research.

    o    Soil washing technologies for organlcs removal are well developed in the
        United States and Europe.  The 8.E.S.T.   process by RCC has shown good
        results for oily wastes.  The HTA and Blotrol processes have also shown
        cost-effective, pilot-scale results.  Harbauer has shown good results for
        silt/clay  soils with  higher finer contents.  A humlc acid extraction
        technique  has shown limited results in removal of organic constituents.

    RECOMMENDATIONS

        Various recomendatlons were made to improve the format of the seminar and
    Increase  Its value to the participants and EPA.

        One suggestion was to organize conference attendees into smaller, separate
    working groups or "committees'.  This would allow for the discussion of many
    topics In  a smaller  setting, enabling attendees to choose a specific area of
    Interest.  These  topics might consist of focused technological techniques or
    particular remedial problems.  Some  topics mentioned included:  analytical
    methods,  acceptable levels of clean-up, analysts of lessons learned, feedstock
    preparation, or comprehensive review of commercial techniques.  These working
    groups would then reconvene and report their findings and conclusions to one
    another.
                                        II
    Another recoomndatlon called for the inclusion of an infernal gathering
place or "hospitality" room so that discussion could continue after  the
presentations and question/answer period.  This would open up the  '
question/answer period for group interaction while allowing specific questions
to be asked at the latter opportunity.  A variation of this idea would be to
allow a period following each presentation for specific questions addressed to
the current speaker, while setting aside a 30-min period as a forun  of general
discussion.

    Several recomendatlons were given on subjects that needed  further
attention for future presentations.  One hope was that there would be more case
studies presented so actual performance of treatment systems could be
addressed.  A standard criterion of information might be required of all
technologies presented so that they could be evaluated on the same basis.  Some
possible questions include:  cost per cubic yard of soil treated, removal
efficiencies of certain contaminants, range of treatment applicability,  and
time or material requirements for remediation.

    Considerations for more In-depth presentations on the mineralogy and soil
size distribution of samples studied were discussed.  Attention should also be
paid to the characteristics and disposal methods of the concentrated wastes and
sludges coning from the treatment processes.
                                                                                                                                           12
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                                      SECTION 3
               INTRODUCTORY REMARKS AND SOIL WASHING TECHNOLOGY OVERVIEW

   INTRODUCTORY REMARKS

       The U.S. EPA Office of Research and Development (ORO) coordinated the
   formation of a program on the extractive treatment of excavated tolls, sludges,
   and  sediments.  The goal of this program Is to Influence and encourage
   commercial development and use of viable systems for treatment of excavated
   contaminated soils from site remediation activities.  Several major program
   areas  that have been  Identified are: (1) problem characterization; (2)
   evaluation of state-of-the-art technologies; (3) development and demonstration
   of promising systems; (4) technology transfer; and (5) coordination with other
   organizations.  Current efforts and Issues within these areas are discussed
   below.

       Of the many ways  to characterize a site, one way Is to characterize by the
   capability of the treatment technologies that are currently available.  As
   such,  one approach is to subdivide the products Into organics, metals,
j_ radioactive  materials, or a combination thereof.  ORO 1s Interested In some of
o the  fundamental questions of Interaction between the contaminants and the fine
vji particles in order to further characterize the specific problem.  Protocols for
   performing treatabtllty studies are needed to understand the extent to which a
   particular site can be remediated.  Currently, a mobile testing laboratory Is
   being  developed to aid In the characterization of site problems.

       ORD has  been coordinating with the SITE Program on the evaluation of
   state-of-the-art technologies.  Technologies have been developed or
   demonstrated In field tests and as a part of the emerging technologies
   program.  Treatment processes that may be evaluated Include the Blotrol system
   and  the Critical Fluids system.  ORD Is also interested In treatabtllty studies
   In  support of regional offices and the Office of Solid Waste and Emergency
   Response  (OSWER) for  a site-specific problem.

       Historically, ORD has built large-scale pieces of experimental equipment
   (e.g., mobile  incinerator) for the development and demonstration of Innovative
   technologies.  Due to the great expenses of these systems, they have begin to
   focus  on  pilot- or even bench-scale tests, of which they have a number under
   development. Promising pilot systems will be used for site-specific
   treatabtllty studies.  A testing and evaluation facility Is presently being
   constructed  In Edison, NO  (E-TEC. the Environmental Technology and Engineering
   Center) to provide an environmentally safe and secure location to test novel
   systems for  the extraction of contaminants from excavated sotls.

       Recently, legislation was passed that It is hoped will encourage the
   interaction  between the Federal government and the private sector.  ORD hopes
   to  assertively use the authority contained within these laws to develop a
   partnership  with specific organizations for technology transfer.  ORD will also
   be  providing technical support to the regions and OSWER for site-specific
   problems.  Additionally, ORD has set aside funding for producing automated
   Information  systems.  These systems will Include treatabtllty Information, cost
   and performance data, as well as other site-specific cleanup data.  ORD

                                          13
intends to actively sponsor further meetings and symposia on subject matter
relative to the extractive treatment of excavated soils.

    It Is ORD's intention to coordinate this program on extractive treatment  of
excavated soils with other organizations, national or international, that  have
common Interests.  Those targeted Include commercial system operators,
academla, other federal agencies (Bureau of Mines, DOE), other EPA programs,
and International companies.

STATE-OF-THE-ART OF SOIL WASHING TECHNOLOGY1
(Presented by:  R. Raghavan, Foster Wheeler Enviresponse, Inc.)

    This study developed a state-of-the-art review of soil cleaning
technologies and their applicability to Superfund sites In the United States.
Research objectives Included summarizing Superfund site soil and contamination
characteristics, soil cleaning technologies, principles of operation, and
process parameters.  A final objective was the assessment of technical
feasibility of soil washing technologies at Superfund sites in the United
States.

    National Priority List (NPL) sites were used as the basis for classifying
contaminants and soil types.  Contaminants were classified as volatile,
hydrophtllc, or hydrophobic organics; PCBs; heavy metals; or radioactive
material.  Cleaning soil contaminated with PCBs or with radioactive material
was beyond the scope of the study.  Soils were classified as either sandy,
sllty, clay, or waste fill.

    Three generic types of  extractive treatments were  identified for cleaning
excavated soils.  They Include:  water washing augmented with a basic or
surfactant agent or with an acidic or chelating agent to remove organics  and
heavy metals, respectively; organic solvent washing to  remove hydrophobic
organics and PCBs; and air or steam stripping to remove volatile organics.

    In water washing with extractive agents, excavated  soil is pretreated  by
removing large objects or hard clods of  soil.  The  soil Is mixed thoroughly
with the appropriate extracting agent followed by solid/liquid separation  to
strip and remove contaminants from the soil.  Separated soil Is cleaned of any
residual extracting  fluids.  The spent extracting agent undergoes posttreatment
to decontaminate the solution for recycle back to the unit.

    Two general techniques for solvent extraction of hydrophobic organics  are:
(1) leaching; and  (2)  Immersion extraction.  Leaching extraction Is a batch
operation In which solvent  Is sprayed over soil contained  in a false-screened
bottom tank(s).  The solvent leaches the contaminant from the soil and  Is
collected at tht bottom after percolating through the soil.  A series of  tanks
Is operated In countercurrent fashion to Increase extraction efficiency.   For
cases  In which the soil contains low-solubility contaminants, fine soils,  or
soil's with a low residual contaminant content, immersion extraction  Is
considered superior to the leaching extraction process.  With immersion
extraction, the contaminated soil is dispersed and  agitated in a tank  filled
with solvent.  After extraction equilibrium is reached, agitation  is  stopped
and the  solid Is allowed to settle.  The solvent  is drained and treated  for
recycle.
                                        14
-------
o
ON,
     Air stripping Is  normally used to remove volatile organic compounds (VOCs)
 from the soil  by vaporizing  the VOCs.  Stripping can be done with steam to
 Increase the rate of  vaporization.  The VOCs are removed from the circulating
 air stream by use of  adsorption or combustion.

     Several soil cleaning technologies employing the three primary extractive
 treatments are described and evaluated within the report.  Technologies
 mentioned in the report for  water washing of contaminated soils with extraction
 agents are:

 o   Netherland's bromide removal from sand;

 o   Heijmans Htlieutechntek's extraction cleaning of heavy metal and cyanide
     from soil;

 o   HVZ Bodemsanering's extractive cleaning of  cyanide-contaminated sandy
     soils;

 o   Ecotechnlek's thermal washing  Installation  for  cleaning sandy soil
     contaminated with crude  oil;

 o   Bodemsanering Netherland's  (BSN)  high  pressure  washing of sandy soil
-    contaminated with oil;

     Harbauer soil cleaning system;

 o   EWH - Aslen - Breltenburg pilot  plant  to  clean  sandy soil contaminated  with
     oil;

 o   Lee's  Farm  lead extraction  from  soil;  and

 o   EPA's  mobile  system  for extracting spilled hazardous materials  from
     excavated soil.

 A  number of continuous extractors employing the solvent extraction  theory
  Include:

 o   Rotocol extractor by Dravo Corp.
 o   Endless belt  extractor
 o   Lurgl  frame-belt extractor
 o   OeSmet continuous  *  belt extractor
 o   BMA diffusion tower
 o   Oe Danskt Sukkerfabrlker (DOS) dlffuser extractor
 o   B.E.S.T.  process

 Air stripping technologies  that were evaluated include:

 o   Holo-FIHe  screw
 o   Rotary kiln/dryer
 o   Hereschoff  furnace
  o   Circulating bed combustor
15
                                                          o   Bubbling bed combustor

                                                              The effective removal of contaminants from  soil  depends on various
                                                          parameters.  Important process parameters Identified for the removal  of certain
                                                          contaminants using a specific extraction treatment process  are listed below:

                                                          Water Washing with Extraction Aoents

                                                          o   Removal of hydrophllic organic compounds
                                                                   pH
                                                                   humic content of soil
                                                                   agitation
                                                                   extraction time
                                                                   soil loading
                                                                   extraction stages
                                                                   wetting agent

                                                          o   Removal of hydrophoblc nonvolatile organic  compounds
                                                                   surfactants
                                                                   caustic agents
                                                                   extraction agents
                                                                   agitation
                                                                   temperature

                                                          o   Removal of heavy metals using chelatlng agents effect of other metal
                                                              cations

                                                                   effect of anlons
                                                                   soil classification
                                                                   temperature of solution
                                                                   Ionic strength effect
                                                                   chelate concentration
                                                                   chelate duration
                                                                   soil-loading
                                                              -    PH

                                                          o   Removal of heavy metals using acids

                                                                   extractant type
                                                                   extractant concentration
                                                                   soil loading

                                                          Solvent Extraction

                                                          o   Removal of nonvolatile organic compounds
                                                                   extraction stages
                                                                   physic*! property of solvent
                                                                   selectivity
                                                                   solid-to-extraction solution ratio
                                                                   temperature
                                                                                                  16
-------
  Air or Steaa Stripping

  o   Removal of volatile organic compounds
          heat
          stripping gas
          soil type
          soil preparation
          posttreatment

     Although extraction of organlcs and toxic  metal contaminants from excavated
  sandy/sllty soils low In clay and humus content  has been successfully
  demonstrated at several pllot-plant-scale test facilities, extraction from clay
  and humus  soil fractions  Is more complicated.   Above-ground extraction of
  organlcs and heavy metals from clay and humlc  soil fractions has not been
  successfully demonstrated on the pilot-plant scale.  Also, the separation of
  the extractant from the soil and regeneration  of the extractant has not been
  successfully demonstrated for clay soils.

     More pilot-scale testing must be conducted to support any statement on the
  environmental and economic practicability of extraction technologies at sites
  tn the United States.

^ASSESSMENT OF INTERNATIONAL TECHNOLOGIES FOR SUPERFUND APPLICATION2
-^(Presented by:  T. Phelffer, EPA/OSUER)

     This presentation summarized the results of a 9-month study by the U.S.
  EPA's Office of Program Management and Technology.  The purpose of this program
  was to Identify and assess  International technologies applicable to hazardous
  waste site remediation in order to promote their use  in the United States.  The
  program was conducted in  two phases:  Phase I  -  Technology Identification and
  Selection; and Phase II  - Technology Review.  The results of Phase II, a
  detailed Investigation of the most promising technologies identified in Phase
  I, are summarized in this report.

     The field team visited  12 research groups, consultants, and manufacturers
  in Holland, Belgium, and  FRG.  Phase II efforts were  successful at identifying
  site  cleanup technologies not currently used In the United States, as well as
  unique applications of technologies used In the United States.  Various types
  of remediation systems were observed Including soil washing, incineration. In
  situ  biological treatment and composting, vacuum extraction and In situ air
  stripping. In situ extraction of cadmium soils,  application of biological
  contactors, and electrochemical dehalogenatlon.

     Among  ,the most Important soil washing findings involved systems observed in
  Holland and FRG.  Five high-throughput soil washing technologies reviewed are
  summarized In Table 1.  A key similarity among all the units was that they
  operate on the principle  that most of the contaminants are sorted to the fine
  materials  (<63 urn), and segregation of these materials from the other size
  fraction 'cleans* the soil.  A major consideration of all washing techniques is
  the fact that as particle reject size decreases, so does sludge residue
  generation.  Cleaning efficiency tends to decrease with decreasing particle
  reject size cuts as well.
                                        17
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                                         In general, pollutant levels and removal efficiencies achievable by  soil
                                     washing  strongly depend on the distribution of the pollutants over .the
                                     different  size fractions and the presence of soil  particles  other than sand
                                     (such as absorbing clay and carbon particles), which are difficult to wash.
                                     The contaminants trapped In the clay clumps cannot be reached by scrubbing, but
                                     If crushed, can be taken out In the sludge.  Where the anount of fine fractions
                                     <63 urn  Is  greater than 20%, the voluae reduction of the contaminated soil  Is
                                     generally  not sufficient to warrant treatment.

                                         Most of the soil washing companies noted that their practical upper  limit
                                     of fines (<63 urn) was 201 to 30X In the soil to be cleaned.   Because the
                                     proportion of fines present Increases the generation of'sludge,  treatment  costs
                                     tend to Increase for finer grained soils.  The Harbauer technology shows an
                                     advantage  of potentially generating less sludge; however, the additional costs
                                     of wash water treatment employed for that technology make It slightly more
                                     expensive  than the other soil washing technologies reviewed.

                                         The Heljmans process works best on sandy soils with a minimum of humus-like
                                     compounds. Because no sand or charcoal filters are employed by Heljmans,  the
                                     system Is  not able to treat such contaminants as chlorinated hydrocarbons  or
                                     aromatic*. Like most soil washing techniques, the throughput and cost of
                                     treatment  Is dependent on quantity of fine fractions (<63 urn) In the soil  to be
                                     cleaned.

                                         The Heljmans system has had Its greatest success treating soil contaminated
                                     by cyanides (CN~).  Heljmans adds hydrogen peroxide Into the scrubber to
                                     react with CN* to form COj » NH4+.  In one experiment, CN" at a
                                     concentration of 5,000 to 6,000 mg/kg dry soil was reduced to IS mg/kg.
                                     Cleaning results of the Heljmans soil washer on seven different types of
                                     contaminated  soil are shown In Table 2.
                                                         !
                                         Vendor-supplied cleaning efficiency data for the other four soil washing
                                     units are summarized  1n Table 3 for a variety of contaminant types.  In
                                     general, the  efficiencies- for heavy metals and cyanides are similar among  the
                                     units.   Based on these data, the OIL CREP unit tends to show greater efficiency
                                     for hydrocarbon wastes, and the Harbauer data shows advantages 1n soils  with
                                     higher clay content.

                                         Soil washing experience In the Netherlands and the Federal Republic  of
                                     Germany (FR6) has  shown that soil washing can be conducted on a large scale at
                                     costs substantially  lower than those of Incineration (although with notably
                                     less effectiveness).  Although most of the technologies generate 10* to  20X of
                                     the Initial volume as sludge, depending on the fines content, work Is being
                                     conducted In  the FRG  to Improve effectiveness of soil washing on fine materials
                                     and to reduce sludge generation.  Typical cleaning efficiencies for soil
                                     washers have  ranged  from 75X to 9SX removal, depending on the contaminant.
                                                                                                                                        20
-------
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                                    SECTION 4
                    TECHNICAL  SESSION  - SITE CHARACTERIZATION
Koc, THE UNCONSTANT CONSTANT3
(presented by:   W.  Lynun,  Camp Dresser HcKee,  Inc.)

    This presentation examined soil  sorptlon equilibria and their subsequent
effect on soil  washing.  Koc may  be  thought of as the ratio of the amount of
chemical adsorbed per unit weight of organic carbon (oc) In the soil or
sediment to the concentration of  the chemical  In solution at equilibrium:
                        oc
                   ug  adsorbed/g organic carbon

                          ug/mL solution
Values of Koc (In the above units)  may  range from 1 to 10,000,000.  Dr.
Lyman's presentation focused on  methods for estimating the organic carbon
sorptlon "constant", Koc,  and Its variation with changing conditions.

    A frequently used expression for  estimating Koc Is:
where:
Koc
KQ
Foc
                organic carbon sorptlon  constant
                measured sorptlon constant
                fraction organic carbon  (0 < Foc <1)
    KQC can be applied to a wide variety  of  soils and sediments.  There Is a
high correlation between KO and Fgc,  and  this equation appears to work over a
wide Foc range (0.001 < F-- < 0.4).   Most topsolls and sediments have FQC
In the range of 0.1X to 10%.  KQ. can be  predicted by using correlations with
Kgy (octanol/water partition coefficient), contaminant solubility, and other
parameters.  In general:

                            log Koc  - A log  X + B

    where:  X » amount of contaminant absorbed

    Although Koc Is referred to as a  "constant*, It depends on several
variables and Its value, therefore,  is highly unconstant.  The following
section deals with many of these parameters  and the effect they have on values
of Kgc.

    There are problems found In the measurement protocols of Koc.  Typical
measurement protocols established by  EPA,  ASTM, and OECO are seldom followed,
resulting In variations of Koc.   These protocols sometimes Involve mechanical,
chemical, or thermal action on the soil,  tending to denature or break up the
the soil in a nonreproduclble way.   This  action may even form mlcropartlcles,
which are nonsettleable.  As such, the final test matrix Is not like soil that
is naturally occurring.
                                       23
     There  tends to be a variability In predictive correlations for Koc.  Over
 90 correlations are found in the literature for Koc and KD, yet a fairly wide
 variability  Is  found In the slopes and Intercepts of the correlation
 equations.   No  rules have been established for the selection of the best
 predictive equation.

     Studies  show a decrease In the sorptlon constant with an Increase In solids
 concentration.   These values have been obtained sediment concentration in the
 order of 10  *xj/L to 104 mg/L.   If the value of the sorptlon constant Is to be
 predicted for soil,  Is It appropriate to extrapolate to a higher solid value?
 Possible proposed explanations for the decrease of the sorptlon constant with
 an  Increase  In  solids concentration are:   (1)  nonsettleable particles (NSP);
 (2)  particle Interaction model;  (3)  implicit adsorbate model;  and (4) kinetics.

     The variable nature of organic matter creates differences  in the value of
 Koc.  A range of Koc  values Is observed for different types of soils and
 sediments.   Some of the uncertainty  may be due to protocol  differences or
 nonsettleable particles,  but there are known differences In humic acids that
 would affect Koc.   Sediment 1s more  aromatic than soil.   It is also  less highly
 condensed, richer In  phenolic  groups and  carbon,  poorer In  nitrogen,  sulfur,
 hydrogen, and carbonyl  groups.

    Dissolved organic  compounds  (DOCs)  affect  sorptlon by:   (I)  enhancing the
 chemical's water  solubility; (2) modifying characteristics  of  the sorbent;  and
 (3) preempting the  sorptlon capacity of the matrix.   True dissolved  organic
 compounds (such as acetone, methanol.  and  acetic  acid) must not  be confused
with nonsettleable particles.  The overall  effect  of  the DOCs  Is  the  lowering
of the sorptlon.  A general relation  can be  expressed  as:
                  In
d(e)Fc
                                                                                        where:
                                                                                                  d.e  - empirical constants
                                                                                                  Fc   - volume fraction of solvent  (0 <
                                                 x < 1)
                                                                                            Temperature also affects sorptlon, but not  In a  predictable  direction.   The
                                                                                        variation of temperature may have counteracting effects on  the chemical's water
                                                                                        solubility and the sorptlon capacity of the matrix.  Host studies  of
                                                                                        temperature effects show < decrease In sorptlon with an Increase In
                                                                                        temperature.  For cases Involving small temperature changes  (e.g., 25/C  to
                                                                                        5/C), the sorptlon will change by less than a factor of two.  If the change  Is
                                                                                        primarily due to a change In solubility, the sorptlon constant can be predicted
                                                                                        by the following equation:
                                                                                                               (KOc'l)        (ST1)
                                                                                                          log      _  - -0.83	
                                                                                                               (Kg7^>        (STZ)

                                                                                            Soil  pH affects sorptlon.   Neutral  acid species (AH) sorb more strongly
                                                                                        than antons (A-).   Protonated  bases (8H+)  appear to dominate, however.  The
                                                                                                                                         24
-------
effect of pH can be predicted by:

                  K0 (eff) - K
    The salinity or Ionic strength of the soil  or sediment  affects  sorptlon  of
organic*.  Three mechanisms nay be Involved.   Sorbed  organic  Ions nay  be
displaced by salt In an Ion exchange reaction.   This  mechanism Is Important  for
cations (BH+).  Also, the activity of the chemical  Is Increased; this  leads  to
enhanced sorptlon for neutral organlcs.   This effect  can  be predicted  by  the
following:

                     c   s                  s
               log (K  /K  ) - 0.83 log (S/S )
                     oc  oc
where:
      log (S/S )  -  KI

-0.0272 log S + 0.134
   third mechanism, which Is not well understood, 1s where the sorbent structure
   characteristics are altered.
-"
    Or. Lyman concluded his presentation with a discussion of kinetic
 limitations as predicted by Karlchoff's kinetic model and Wu/Gschwend's radial
 diffusion model.  Dr.Lyman noted the Wu/Gschwend model predicts slower
 sorptlon/desorptlon rates for larger particles and high sorptlon constants.

 CASE  HISTORIES FOR UNDERGROUND STORAGE TANKS4
 (Presented by:   R. Griffiths, EPA/RCB)

    This presentation dealt briefly with the capabilities of and Information
 contained within a computer data base systea written to access Information on
 case  history  files.   Information entered Into the progran was generated by the
 Releases Control  Branch or acquired from the Superfund Technology Demonstration
 Division and  covers such areas as  landfill, remedial action, removal action,
 and underground  storage tank corrective action.  The program presently utilizes
 27 search criteria enabling the user to search case history files for various
 Information.   Some examples of available search criteria are:  treatment
 technology,  site geology and hydrology, chemicals Involved, volume affected,
 and sources of contamination.  No  soil washing technology case studies are
 currently contained  In this file.

 CHARACTERIZATION OF RCRA/CERCLA SITES WITH CONTAMINATED SOIL5
 (Presented by:   P. Esposlto, Bruck, Hartman i Esposito, Inc.)

    Recent figures on the number of hazardous waste sites In the United States
 Indicate  that there are approximately 22,000 to 24,000 uncontrolled CERCLA
 sites, 3,000  RCRA-pernltted treatment/storage/dtsposal sites, and another
 10,000 locations where hazardous wastes are currently generated, but not
 treated,  stored, or disposed.  These RCRA/CERCLA sites were characterized with
                                        2S
                                                                                         respect to geographical location, type of operations, type of contaminants,
                                                                                         affected media.
                                                                              and
                                                                    i
     Of 151 ROOs reviewed for soil  data it Superfund sites, 60 had no
 Information on soil type, 30 were  classified as sandy, IS were primarily clay
 soil, and 45 were a mixture of sandy-clay soil.  From this data, 75 ROOs, or
 half of the sites, have sandy or sandy-clay soils amenable to soil washing.
 Two-thirds to three-quarters of the sites needing soil treatment are predicted
 to be in the eastern United States.  In a CERCLA soil  study,  of 116 ROOs
 reviewed, a soil  description was found for 95 ROOs.  Fifteen percent of these
 ROOs contained sandy soil (Fig.  1).  Typical  Superfund soil  and sludge
 contamination levels for selected  contaminants are shown in  Table 4.  No
 Information was found on soil  type or soil  contamination at  RCRA sites.

     In  1987,  this Information  was  used as the basis for development of a
 surrogate Superfund soil  for research purposes.   The surrogate soil, or
 synthetic soil  matrix (SSM), was prepared by  blending  prescribed amounts of
 clay, sand,  gravel,  silt,  and  topsotl  together In two  15,000-lb batches using a
 conventional  concrete mixer.   A  select  group  of organic and  inorganic
 contaminants  known to frequently occur  at CERCLA sites was then added to the
 soil  through  a  series of  pilot-scale  blending operations.  This synthetic soil
 has  been  used as  a test matrix for  evaluating the treatment efficiency of
 several different  technologies Including  soil  washing/volume  reduction.

     The development,  characterization,  and preparation/manufacture  of this
 synthetic soil was also discussed.

 SITE CHARACTERIZATION TECHNICAL SESSION:  SELECTED QUESTIONS AND ANSWERS

Question 1:  What  Is the purpose of making the synthetic soil?
                                                                                        Response:
                                                                                        Question 2:
             (Esposlto) So five technologies (incineration, low-temperature
             sorptlon, solidification,  stabilization, chemical treatment, and
             soil  washing) can  be evaluated on four soil samples having the
             same  soil matrix and contaminants,  but with varying levels of
             contaminant concentrations.

              What do you consider to be  clay In terms  of particle size?  Oo
              you  consider particles below  100 urn or 20 urn?
                                                                                        Response:      Below 10 urn.
                                                                                        Question 3:
                                                                                                  \
                                                                                        Response:
                                                                                       Question 4:
             Could you compare and contrast treatment technologies  that  are
             developed here versus Europe?  How do the two compare?

             (Phieffer) - They appear to be doing more demonstration and
             Implementation because they have hard numbers.  Also,  they  have
             levels that .they can design on, which we don't have over here.

             You indicated that with basic organics the retention mechanism
             was cation exchange,  but that seems to be contradictory relative
             to the previously mentioned relationship between Koc and organic
             content In soil.   Am I  missing something?
                                                                                                                                             26
-------
                     of OCCWTMCM
SeWWUM
                                                                                                      TABLE  4.   TYPICAL  SUPERFUNO SOIL AND SLUDGE CONTAMINATION
                                                                                                                LEVELS FOR  SELECTED CONTAMINANTS[5]
                                                                                                                                           Average
                                                                                                                                              PP"
                    Maxtonn
                      ppa
                                                                                          Volatile^

                                                                                          Ethyl benzene
                                                                                          Xylene
                                                                                          1,2-dlchloroethane
                                                                                          Perchloroethylene
                                                                                          Acetone
                                                                                          Chlorobenzene
                                                                                          Styrene

                                                                                          Semlvolatllei

                                                                                          Anthracene
                                                                                          PCP
                                                                                          Bts(2-ethy1hexy1)phtha1ate

                                                                                          Inorganics
3,200
8,400
  580
  540
6.800
  360
  120
4,800
  700
1,900
 53,000
150.000
  6,700
  9,200
 55,000
  3,900
  1,100
100,000
  7,200
 22,000
Pb
Zn
Cd
As
Cu
Cr
N1
3,100
5,000
180
90
2,100
370
200
61,000
67,000
3.000
950
52,000
3,000
1,900
                                                                                                                                  28
-------
Response:     (Lyman)  - Yes,  you're  right.  That relationship between total
              sorptlon and organic carbon content does not generally hold for
              organic  bases.   So,  I  had preceded my  Initial conments by saying
              they were principally  for neutral organic chemicals.  But, when
              you have an organic base to the extent that It Is protonated, the
              organic  carbon  content plays a secondary or tertiary role In the
              total sorptlon.
                                       29
                                                                                                                                     SECTION 5
                                TECHNICAL SESSION
                   TECHNIQUES/EXPERIENCES FOR METAL EXTRACTION


HYDROMETALLURGICAL TREATMENT OF SOIL6
(Presented by:  U. Schnldt, U.S. Bureau of Mines)

    The U.S. Bureau of Mines 1s the federal agency responsible for a number of
raijor activities related to the Minerals Industry.  Among these
responsibilities Is the performance of research on mining and metallurgical
technologies.  About three years ago, the Bureau began to explore the matter of
the application of Us metallurgical technologies to the problems of
remediation of contaminated Superfund sites, both mlnerals-productlon-related
sites and sites that had no direct association with minerals production.

    Several examples are discussed In this paper that will help to demonstrate
the kinds of treatment techniques that are under Investigation.  The first two
are from ongoing studies of contamination associated with mining sites, both
Involving arsenic contamination.  Then work on low-level arsenic solution
treatment Is described.  The last example Is directly related to work with EPA
on Superfund sites.

    Many solid wastes resulting from minerals production, e.g., tailings and
flue dusts, are not very different from soils In terms of such characteristics
as mineral makeup, particle size, and their response to cleaning technology.
Some of the largest tailing contamination problems In this country Involve
deposition of tailings along.stream banks and at the bottom of lakes and
reservoirs—sedimentation that results In a mixture of mineral wastes and
natural soils.  A prime example of this mixing Is the stream bank contamination
along Silver Bow Creek In Montana.  These tailings are exposed to air and water
erosion, and thereby contribute to arsenic contamination In Silver Bow Creek
downstream from Butte, Mont.

    Analyses of these tailings show an average arsenic content of about 500
ppm.  Mlneraloglcal examination of these tailings determined that the material
Is mostly quartz with lesser amounts of K-feldspar and plagiocltse.  Minerals
heavier than quartz and feldspar make up approximately 0.1* of the tailings and
consist mostly of sphalerite with lesser amounts of galena, chalcopyrlte,
pyrlte, barlte, wolframite, and zircon.  Arsenic was present as a
copper-arsenic sulflde, either enarglte or tennantlte, and In much smaller
quantities as various sulpho-salts together with copper, zinc, vanadium, and
bismuth.  Particle size of as-collected tailings was determined to be mostly
between 28 and 100 mesh by screen analysis.

    Detailed leach tests were conducted with 10 g of tailings In 50 ml of leach
liquor to determine the effects of acid concentration, time, and temperature.
Leaching with plain water at temperatures between ambient and boiling and with
reaction times up to 4 h was not successful.  Maximum arsenic concentration In
any of the water leach solutions was 6 mg/L.

    Ambient temperature acid leaching with H2S04, at concentrations up to 5X
50,000 ppm) HjSOj, was not significantly better at removing arsenic from
                                                                                                                                         30
-------
    the tailings.  Leach solution concentrations reached 42 mg/L arsenic, but the
    arsenic concentration of the solid tailings residue had not changed.

        Increasing the temperature and/or the acid concentration Increased the
    arsenic extraction, but complete removal was not achieved.   Solution
    concentrations reached 103 ng/L As at leach conditions of 5 wtX HjSO* at
    80°C  for 2 h, but only about half of the arsenic was leached fro* the
    tailings.  The solid residue still contained about 200 ppn As.   Further leach
    tests are expected to find appropriate conditions for greater arsenic removal
    from  the tailings.

        Another, less mature study relates to Whltewood Creek (n South Dakota.  The
    Lead-Deadwood area 1s one of the largest Superfund sites In the country,
    Involving over 100 miles of contaminated floodplaln along Uhltewood Creek, the
    Belle Fourche River, and the Cheyenne River.  Arsenic-bearing tailings and both
    red and brown oxidized tailings were obtained from this area.  Hlcroscoptc
    examination shows that all three tailings are not very different In mineral
    makeup fro* tailings obtained from regular soil.  The tailings are mostly
    quartz with lesser amounts of blottte, pyroxene, hornblende, ankerlte, Iderlte,
    Iron oxide, and less than IX sulfides.  Pyrrhotlte Is the most common sulflde,
    followed In abundance by purlte. and In trace amounts by arsenopyrlte.
    ArsenopyHto Is the only arsenic-bearing mineral Identified In this tailing
    sample.  Leaching studies are about to begin on these wastes.  It Is expected
_£_.  that  the results will parallel those related to Uhltewood Creek.
H-1
j=      Beyond the leaching tests, there are some other Interesting aspects to
    these studies.  One of the problems In arsenic treatmnt not yet addressed by
    most  researchers Is further treatment and/or disposal of the arsenic-laden
    leach liquor.  Solution concentrations of 100 txj/L. while low by metallurgical
    standards, are very high by environmental standards.  Complete resolution of
    the arsenic problem In solid wastes such as tailings or contaminated soils may
    depend on resolution of this low-level arsenic solution treatment problem.

        Research at the Salt Lake City Research Center has found that the most
    promising method of resolving this solution treatment problem Is to adsorb the
    arsenic on a ferric oxide/ferric hydroxide matrix.  This method has been
    successful In lowering arsenic concentrations to significantly below the
    National Primary Drinking Hater Standard of 0.05 ng/L.  The precipitate from
    this  procedure Is a stable solid, which successfully passed the Extraction
    Procedure Toxlclty (EP Tox) Test and would therefore be classed as a
    nonhazardous waste.  The sludge contained about IX arsenic, which Is between 25
    and 50 times more concentrated than was the tailings, resulting In a
    significant decrease In the volume of the arsenic-laden waste.  Long-term
    stability Resting currently In progress on this sludge Indicates no leaching of
    the arsenic  Into water over a 3-month period.

        .The last example of waste metals extraction relates to an ongoing study of
    the treatment of wastes from a battery disposal Superfund site In Region V.
    The wastes of concern are 'hard rubber' casings and lead-contaminated soil.

        The characterization work on the casing material revealed that the lead
    contamination was 1n the form of lead compounds (principally sulfates) and
    occurred as crack filling materials.  The Bureau of Mines researchers at the
                                            31
Roll a Research Center crushed the casing material to  -3/8  1n. and washed the
product In water.  The processed casing material, which has a fuel  value of
12,000 to 13,000 8tu/lb, showed EP Tox results of less than 1 ppm.'wlth total
lead levels of less than 100 ppm.  This left the sludge from the
crushing/washing of the casings and the contaminated  soil.  The Bureau tried a
number of leachants and settled on fluoslllclc acid,  a waste product from the
production of phosphate.

    Initial tests showed that a carbonatlon step followed  by the fluoslllclc
acid leach significantly reduced the lead  levels.  However, the Bureau was
Initially unsuccessful In meeting EPA's goals of 5 ppm and 500 ppm  for EP Tox
and total lead, respectively.  When the results  of the characterization studies
became available, they showed that the soil contained significant amounts of
metallic lead In addition to the lead compounds  that  the fluoslllclc acid could
effectively deal with.  The answer was to  add a  small amount (less  than O.SX)
of nitric add to the final rinse.  The laboratory-scale tests are  now
consistently producing results of less than 5 ppm EP  Tox,  and less  than 500 ppm
total lead.

    There are a number of more sophisticated approaches that may have promise
as part of treatment processes for Superfund sites.   One such approach on which
the Bureau has done a considerable amount  of research and  which  Is  In growing
use by the minerals Industry Involves  fine bubble column flotation.  The
critical parameters governing the success  of this approach are the  size of the
particles, the selection of reagents,  and  the establishment of operating
parameters such that the probability of capture  of the particles of Interest
are maximized.  The benefits are  Improved  'grade"/yield and reduced capital
costs compared to conventional flotation cells.

    The Bureau has  found that  Its experience  In  metallurgical  technology has
allowed It to successfully treat  Inorganic wastes from both NPL-listed and
unlisted sites.  They believe  that these techniques  can be applied  to a wide
range of Inorganic  treatment needs at  costs  that are lower than,  or at least
competitive with, the alternatives.

LEAD EXTRACTION  FROM  EXCAVATED SOIL7
 (Presented by:   A.  Zownlr. EPA/ERT)

    The Environmental Response Team  (ERT)  of the U.S. EPA  provides  expertise
and consulting  In treatability studies;  sampling and assessment;  analytical
methods; alternative  technology,  and personnel  training  for  hazardous waste
 sites  and materials situations.   The Emergency  Response Division, Office of
Emergency and Remedial  Response  (OERR) and U.S.  EPA  Region V  requested the ERT
 to provide, support  at the  Lee's  Farm  site  In Moodvllle, His.,  a  former battery
recycling site.  The  purpose was  to evaluate the specific  equipment and
methodologies being used at the  site  to  extract  lead from  soil.

    The processing  and  disposal  of  spent  lead  storage battery  cases at the
 rural  site had  contaminated the  soil with  lead  and  lead compounds.   A
 preliminary excavation  and a detailed  site survey  Indicated  the  presence of
 approximately  15,000  yd-* of contaminated material  (mostly  soil  and  broken
 battery casings).   As an option  to  land  disposal of  this material,  the method
                                                                                                                                              32
-------
      of choice was  soil washing with a chelatlng agent to extract the lead
      contaminant.

          The  objective of  this study was to explore the feasibility of soil washing
      with EOTA (•thylenedtantnetetraacettc acid) to remove lead contamination from
      contaminated soils at  the Lee's Farm site.  Contaminated soil from Lee's Farm
      averaged 50,280  ug/g  total lead and 65 mg/L Extraction Procedure Toxlclty (EP
      Tox) lead.  To facilitate materials handling and soil/liquid separation, the
      soil was classified Into three fractions prior to soil washing:  oversized,
      coarse,  and fine.  These fractions comprised approximately 25X, SOX, and 25X of
      the whole soil,  respectively.

          Soil washing comprised a four-step process:  chelatlon, a polish rinse, and
      two water rinses.  For chelatton, the extractant was a 20 wtX aqueous solution
      of Clba-Celgy  SequestreneK 220 tetrasodlum EDTA.  The 20X EOTA concentration
      was chosen to  replicate work previously performed at Lee's Farm by PEI
      Associates under contract to EPA.  The chelatlon solution was adjusted to pH
      7.0 because the  conditional stability constant of the EDTA-lead complex was
      favored  over that of the EDTA-Iron complex.  The EOTA solution and coarse soil
      fraction sample  was mixed 45 mln at 100 rpm to suspend the particles.  Soil
      loading  (the wtt of soil In the chelatton solution)  was varied.  After
£    chelation, vacuum filtration In a Buchner funnel was used for soil/liquid
\jt    separation.  Next, soil was exposed to three successive rinse steps:  a OX, 2X,
      or 5X EOTA polish rinse followed by two 01 water rinses.   Each rinse duration
      of 20 mln was  followed by solid/liquid separation.   All  experiments were
      performed at room temperature and ambient pressure.

          For  the sequential chelations, the 20X EDTA chelatlon solution was
      repeatedly exposed to  new batches of contaminated soil  (25X loading).  The
      coarse soil fraction was extracted with the chelation solution for 15 minutes
      followed by 5-min, 2X  EDTA polish and two water rinses.   Soil/liquid separation
      occurred between steps.  After soil washing, the chelatlon solution was saved
      to extract the next sample of contaminated soils until  the required number of
      sequential chelations  were performed.

          The  oversized (> 0.25 in.) soil fraction was treated  with an EOTA-free
      water wash rather than an EDTA extraction.  The wash consisted of spraying the
      oversized particles with a designated amount of delonlzed water based on a
      soil/water weight ratio.  After spraying, the soil was  air dried before EP Tox
      analysis.

          Soil washing of the coarse fraction with 20 wtX  EDTA  reduced lead 95X to
      97X with a total lead  concentration of 656-3411 ug/g remaining  in the treated
      soil.  Soil  loading (the percentage of soil in the extraction mixture)  of 25X
      and  45X were used, and the Increase did not significantly reduce extraction
      efficiency.   The EDTA  polish rinse,  following the EDTA extraction step,
      adversely affected treatment compared  with an EDTA-free (water)  rinse by
      Increasing EP  Tox lead and not reducing total  lead In the treated soil.   The
      45-min extraction step was shortened to 15 mln for subsequent experiments
      because the lead uptake by EOTA was  occurring  more rapidly  than  expected.
      Sequential extractions, where an extraction solution was  repeatedly  exposed  to
      contaminated soil,  were performed  to replicate field conditions.   These
                                            33
  experiments found that the EOTA solution still reduced lead significantly after
  11 sequential extractions.

      In conclusion, this study found that COTA is an effective extraction  agent
  for lead-contaalnated soil and can meet EP Tox criteria, and that soli washing
  Is an emerging technology applicable to a wide range of contaminants in soil.

  INNOVATIVE ELECTROMEMBRANE PROCESS FOR RECOVERY OF LEAD FROM CONTAMINATED
  SOILS8
  (Presented by:   R. Krlshnan,  PEI  Associates,  Inc.)

      This  paper describes  research conducted to Investigate the process
  characteristics, design,  and  economics of a soil-washing process employing an
  electrooembrane reactor (EHR)  for treatment of contaminated soils for recovery
  of heavy  metals such  as lead.   Fig.  2  provides a  highly-simplified overview of
  the soil-washing process.   The process uses EOTA  as  the  chelatlng agent and
  recovers  lead by electrodeposltion.  The  primary  objective of  the research was
  to  optimize, via bench-scale tests,  the process variables  for  the chelatlon and
  electroplating  (EMR)  operations of the process.   The classification  and
  dewataring steps,  though crucial  to  the overall process, represent existing
  technology and  were not studied specifically during  this research.   The process
  results In a lead  product containing about  90  wtX lead at  optimum process
  conditions.

     Soil treatability testing was conducted to determine the optimum conditions
 for soil-EDTA reaction to:  (I) maximize lead chelatlon; (2) minimize EOTA
 consumption; and (3) minimize reaction tine.  The soil treatability  procedures
 developed for this study were performed on lead-contaminated soil samples  from
 two Superfund sites: Arcanum near Troy, Ohio,  and Lee's Fan* 1n Woodvllle,
 WIs.  Table 5 provides the analysis of the metals content of these two  soils.

     Previous research on the EMR has been performed In the context of
 regenerating Ion-exchange resins.   The  current research expanded upon this
 application.   Several  variables are of  Importance In the experimental design of
 the EHR test.   These are:   (1)  electrode potential; (2) current density; (3)
 pH; (4) current efficiency;  and (5) chelate concentration.

     EMR experiments were performed on 0.2X,  l.OX,  and 3.OX Pb solutions.  The
 three primary  control  variables of Interest  In  the EMR  bench-scale experiments
 were current density,  lead  concentration in  the chelate,  and cathode  solution
 pH.

     Results showed  that  In all  cases  an Increased  quantity  of lead was  plated
with Increasing  tine.  Extremely high lead recoveries and current  efficiencies
were observed for the  3X and IX lead  solutions  during the experimental  tine
period.  It appeared,  however,  that current  efficiency  (and  subsequent  lead
removal) at the  starting lead concentration of 0.2X was low  regardless of pH or
current density.  Lead recoveries were below 40X at the 0.2X lead  level  for the
experimental time period.  Greater time periods should result In higher  lead
removal efficiencies for the low lead solutions.  However, lead removal
efficiencies approached 90X for the IX and 3X lead solutions.
                                                                                                                                             34
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                                                                              TABLE 5.   CHEMICAL ANALYSIS OF TEST SOILS [8]
                                                                                         (ug/g on as-received basis)
                                                                                                          Soil  source
                                                                      Element
                                                                      Cadmium
                                                                      Calcium
                                                                      Chromium
                                                                      Iron
                                                                      Lead
                                                                      Zinc
                                                                                              Arcanun
     4
59.630
    19
20.790
78,950
   110
                          Lee's Farm
     1
47,340
    14
22,010
38,670
    81
                                                                A higher current density produced a faster plating rate.  It should also be
                                                            noted that high-current density produced a spongy lead deposit on the
                                                            electrode.  High plating efficiency was achieved at higher Initial lead
                                                            concentrations.  There was no apparent effect of Initial cathode solution pH on
                                                            plating efficiency.

                                                                Based on the experiments for the 0.2% lead liquor, the current efficiencies
                                                            were higher at lower current densities, decreasing from 40X at a current
                                                            density of S ma/car to approximately 20* at 25 ma/cor.  There was no
                                                            apparent effect of pH on this relationship.  In the full-scale process, the
                                                            current efficiency should not be a controlling factor In the economics, because
                                                            power costs are Insignificant compared to other cost elements.  Time, however,
                                                            Is  an Important factor, because It relates to labor cost. Consequently It Is
                                                            desirable to run as high a current density as possible.

                                                                This bench-scale research has shown the feasibility of the two essential
                                                            process steps of an Innovative soil-washing process:  chelatlon and electro-
                                                            deposition.  A long-term pilot-scale demonstration at several actual sites 1s
                                                            necessary to develop the data required for commercialization.
                                                             METAL EXTRACTION TECHNICAL  SESSION:  SELECTED QUESTIONS AND ANSWERS

                                                             Question 1:    Most  of  us working with lead extraction seem to get about a  95*
                                                                           removal, give or  take  a few.  Would you elaborate on the point
                                                                           you brought up about the certain form of lead that remains and  1s
                                                                           unchelatable?

                                                               Response:    (Krlshnan) -  Our  Initial assessment of the speclatlon  of lead was
                                                                           based on gut  feeling.  The fact that since only tonic  lead lends
                                                                                                    36
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              itself to chelatlon and  because you do have metallic lead
              present,  especially at battery sites, along with lead dioxide and
              lead sulfate,  the  chelatlng  agent does not go for the metallic
              lead.   Getting the lead  Into Ionic form  Is where this all comes
              from.

              (Zownlr)  - He  had  a theory that the lead nay be copreclpltatlng
              with other Minerals like Mgnesluat carbonate.  Also, I believe
              possibly  that  In the aluminum/silica matrix, the lead Is being
              substituted for the aluminum Ion.  Does  anyone have any other
              Ideas?

              (Trost) - Under certain  natural conditions, you can get a
              plumbogeroclte, which Is a lead/Iron hydroxide sulfate.  I think
              you would do well  to check Into the presence of plumbogeroclte.

Question 2:    What are  the estimated costs (for the electromembrane process)
              and what  do those  costs  Include?

  Response:    (Krlshnan) • $150-220/ton, which Includes excavation and
              polishing of the effluent water.

Question 3:    In your process, do you  deposit lead from the clean solution or
              dirty solution?

  Response:    (Krlshnan) - The lead Is deposited from  the clean or filtered
              solution.  The filtered  chelate would fora the cathode chamber of
              the electromembrane reactor.

Question 4:    What affect did increasing the concentration of other metals, say
              cadmium,  have  on the process?

  Response:    (Krlshnan) - We looked at one site that had cadmium and some
              lead.   The lead preferentially attaches  Itself to the chelate as
              compared  to the cadmium.  The optimum pH of both are comparable.
              We were able to reduce some  of these soils to below the toxlclty
              level  for lead, but not  for  cadmium.

Question S:    About the 201  concentration  of the EDTA, where did you arrive at
              that percent?

  Response:    (Zownlr)  - It  was  available  and it worked on our soil.   We did
              try one run at the maximum you can get, which I think is 39X, and
              we weren't getting anything  different.
                                                                                                                                      SECTION 6
                   TECHNICAL SESSION - TECHNIQUES/EXPERIENCES
                       FOR RADIOACTIVE MATERIALS EXTRACTION


SOIL WASHING AND CHEMICAL EXTRACTION OF RAOIONUCLIDES9
(Presented by:  Bill  Richardson, EPA/EERF)

    The Office of Radiation Programs within the EPA Office of Air and Radiation
1s comprised of three Divisions:  (1) Criterion and Standards;  (2) Radon; and
(3) Analysis and Support.  The Analysis and Support Division is responsible for
guidance in characterization and investigation of radioactive-contaminated
sites, technology development, and the Volume Reduction Chemical Extraction
(VRCE) project.  This presentation provided an overview of work accomplished
under the VRCE project for the decontamination of radioactive soil.

    The VRCE project, primarily located at a Montgomery, Ala. facility, was
developed In three stages:  (1) mineralogy; (2) treatment (soil washing and
chemical extraction); and (3) implementation.  Radioactive soils used for
experimentation were taken from the Glenrldge/Montclalr, N.J. areas.  Soil from
both areas was contaminated with radium (226) and thorium (230) years ago
during a radium extraction process.  The primary contaminant was BaRaS04.

    Soil samples taken from the Glenrldge and Montclair areas underwent
characterization studies to evaluate soil sizing and distribution of radlonu-
clldes.  The Montclair soil was received in barrels, while the Glenrldge soil
was excavated from * field.  The contamination level of the Montclair and
Glenrldge soil was 180 pCI/g and 800 pCi/g, respectively.  A third soil, termed
the "representative soil," was excavated from a vacant lot and had an average
radium contamination of 53 pCi/g.  Soils high in radioactivity were chosen to
facilitate the analytical procedures.

    From evaluation of the sized soil samples, a large Increase in activity was
found In the Nos. 16-30-sieve soil fraction.  The activity of the smaller
particle size sample was almost double the activity of the larger particle size
sample for Glenrldge and Montclair soils.  However, the representative soil did
not show as large of an Increase in activity between particle size fractions.

    Initial washing studies consisted of rinsing the three samples with
slightly acidic salt solutions (NaCl, KC1. CaCl, EDTA).  The filtrate from this
study contained high levels of soluble radium.  In an effort to remediate the
soil without solubl11zing any more radionuclldes, the use of salt solutions was
discontinued and substituted with water.

    A particular sieve-size sample was shaken gently (100 rpm) with water for  1
hour.  The samples were shaken gently, so that soil particles were not broken
Into smaller sizes.  Samples were filtered and then evaluated for specific
activity.  The old mill tailings standard of 15 pCi/g was used as a criterion
of performance.  Even  though one-step washing of the samples showed relatively
modest removal percentages, most of the specific activities were not close to
the standard of IS pC1/g.
                                                                                                                                          38
-------
  ,» Vi""1  ltudy w" PtrfoPB«d to determine the effect an Increased  shaker
 ™  ,h!d "I/*"0!!1 P«rcMt*9«s.   The rite was Increased fro* 100 rpm to350

 «Tl  wsUr.1o;^r!? Jlr"'1",;!0"*1:  ™rt*-f"« P"™' o? the fental.lr
 ?S Ir?/  r««v«r«d Jt 350 rpm.   The weighted average activity was approximately
 13 pCI/g.  The specific activity of the washwater was less than 25 pCI/l.


 RADIUM(226) REHOVAL FROM A CONTAMINATED SOIL10
 (Presented by:  K. Haque. Canadian Center for Mineral and Energy Technology)


 H.» A !°l!er' P.1'" of 1lnd n"r ' r«1dent1al area In Ontario has been
 ToSneV2 T S0"1"!?1!!*1 "Uh r»dlu"(226).  MacLaren Engineering? Inc. of
 Toronto, conducted a radiation  survey at this site, and their results  Indicate
 the presence of approximately 400 tonnes of rad1u»(226)-contam1nated  soil
 having a radlu* level on the average of 37 pCI/g soil.


 ™H Jh8 Ext?'Ci1V? Met»nur9y «-«l>or«tory of CANMET (Canadian  Center for Mineral
 for tK!r?lJ!^n0l°9yJ,Undrt00l(^h* r«P»«H>111ty to develop chemical methods
 for the remova  of radium from  this contaminated soil.  The radium level of the
 as-received soil  was 105 pCI/g  soil.  The radioactive materials can be removed

                      J011  bV?r10u' <"thodl-  for examp>« b' '••'"3 -m
      T     .         >  ?r " Chel»t1n9 reagent,  or by gravity  separation.
       $.obJ*CW "?*  to reoov«  «'"«t »"  of the radium and to obtain soil
    h  background levels  of radium  of 2 to 3 pCI/g soil.            »«"-«in son


    Mlrf,r«1!SS;4Mti?inlt'd,  »"  «"•»'• (Approximately 10 kg) was supplied
          ?h^2 \   A  2'  '??'   "00d Ch1p$ lnd $tone "lec« W8re rem<>»«d by
          The air-dried soil  was  sized to 80* -200 mesh  (74 urn)   All  the leach

                     °n5   9 Jo11 per te$t'   The calculated  amount of the
                            t0  the $o11  ""p'«  '" order  to ro*1nt»1n » defined
                           e r"gent "nd JoMd* 1n the lwh  Jl«"-ry.   At the
«t«r     l.             H"?,?" fnt«red «nd the r"1du« "" «*h«l »l"h
water.  Dried residues  and  the  filtrates were analyzed for rad1u»(226)   Unless
otherwise stated,  radlu*  In this  report  refers  to rad1um(226)


h«rfr2rhi«l!r °M"Ch *!!*! "" Sonduct«d on  tn«  "11  utilizing either water.
Mon 5hl?  5 fhld'  % nUHc  'Cid'  Th1$ 1eich  pr°9r« "»* b«"d on th« «»«"P-
O?«I,M!   f K? rid1u"Jeo"P°und or compounds In  the  soil were  soluble or even
slightly soluble In acid, then virtually radium-free  soil could be obtained.
                      'U01" '!) Tib1t 6<  5lMrly eon"™«d that radium in this
an    ,      i     thS B^«°f * *Pir1n9ly "l«bl« salt or salts, such as
Rlf°4; «»B«($04),, or RaPb(S04),.  Water  leaching at 50°C could not
solublllze i»r« than 5X of the radium. The best leach residue. In terns of  the

lnTnYid,rr.C°ne'ntr?t1on (3° pC1/9> so11' w" obtained by Caching with
H?i/tJ2.  Inr"*-??'!8  T!V?r th* *Cld COMWIPt1<>'' «* °.«1t« high (260.0  kg
radium from the 'soil          Caching essentially could not solublllze any


    The extraction data In Table 6 lead to the conclusion that the solublllza-
tlon of radlw  took  place at high acidity through equilibration between the
                                      39
TABLE 6.   ACID LEACHING OF THE SOIL (50% SOLIDS, 2 HR RETENTION)[10]

Leachant
(g/kg soil 1)
H20
H;0
HC1 - (44.0)
HC1 - (600.0)
HN02 - (210.0)

Temp.
°C
22
50
22
22
50

Ra-qrade
Feed
105
105
105
105
105

(oCI/a)
Residue
103
100
98
30
135
Ra
extraction
wtX
1
5
7
78

Weight
loss
wtX
--
--
6
21
22
                                                                                                                                        40
-------
sparingly soluble radium compound (e.g.,  RaS04)  and the chloride anlon
(CD-

    These results Indicated that radium extraction may even take place by
leaching with Cl" under mildly acidic conditions or with excess Cl  In the
leach slurry.  Accordingly, a series of tests was conducted on the contaminated
soil with water acidified to pH 1.0 to 2.0 with  hydrochloric acid, and also
with chloride salt solutions (e.g., NaCl, KC1),  respectively.  Tables 7 and 8
show the leach data.

    The leaching of the soil with water alone provided marginal extraction of
radium (Table 6), but leaching with water acidified with hydrochloric acid to
pH 1.6 provided 43X radium extraction and yielded a residue with 60 pC1 Ra/g
soils.  However, second-stage leaching on the first-stage leach residue with
the fresh water and hydrochloric mixture at pH 1.6 Improved radium extraction
marginally  (2X to 3X).

    Generally, some organic matter  such  as humlc acid or hydrocarbon residue Is
present  In  the soil.  This organic  matter may cause inefficient extraction of
radium.  Therefore, acidic water  leaching was conducted on soil samples
prewashed with HC1, ethanol,  and  then  finally with water.  Radium extraction
 Improved to 621,  and  the  leach  residue contained 40 pCi Ra/g  soils.

     Radium  leaching from the  uranium mill  tailings with a  salt  chloride
 solution such as NaCl or KC1  or by a chelating  reagent  (e.g.,  EDTA)  is well
documented  in the literature.   Accordingly,  a series  of tests was conducted on
 the soil with NaCl,  KC1,  and  EDTA,  respectively.   Leach results are  shown In
 Table 8.

     The extraction data In Table 8 demonstrate  that radium is extractable by
 leaching with both chloride anions (Cl") or  by  a complexlng reagent  such as
 EDTA.  In this test program,  both NaCl and KC1  were applied separately for the
 leaching of radium from the soil.  However,  potassium chloride is more «yf««j-
 tlve than sodium chloride.  The highest radium  extraction  (62X) was  obtained  by
 leaching with 151.0 g KCl/kg soil with 50* solids In  the  leach slurry,  but the
 leach residue still contained 40 pCi Ra/g of the soil.

     A complexlng reagent such as EDTA (ethylenedlamine tetraacetate) was also
 somewhat effective In the extraction of radium from the soil, but was not so
 effective as NaCl or KC1.  Here, the highest percent  of radium "trac"" (29*'
 was obtained by leaching with  100.0 g EOTA/kg "11. at 50°C with 50* solids
 In the  leach slurry.

     The removal of radium from this soil by chemical  methods will require
 further work as none of the leachlngs were very effective.   In addition, the
 recovery or removal  of Ra(226) from leach liquor Is still  an unresolved
 problem.   In view of these limitations  and the apparent chemical stability of
 Ra compounds, the physical removal of these 4.000 tonnes of radium-contaminated
 soil  from  the present  location and disposal In a uranium mill  tailings site or
 an  underground  depository of a uranium  mine would be a logical choice.
                                         41
      TABLE 7.  CHLORIDE LEACHING WITH LOW ACIDITY  (30°C, 2 HB, pH ,1.6)(10]
Leachant
Pulp density
  X solids
 Ra-orade (oCI/ol
Feed        Residue
Ra-extractlon
     wtX
H20 + HC1
H20 + HC1
20
20
IDS
105
60
40
43
62*
*  The soil sample was prewashed with carbon tetrachlorlde,  ethanol,  and
   finally with water.
               TABLE 8.  LEACHING WITH CHLORIDE SALTS AND EDTA[10]
Leachant
9/kg
NaCl -
NaCl -
KC1 -
KC1 -
EDTA -
EDTA -
EDTA -
117.0
117.0
151. 0
151.0
100.0
100.0
100.0
Pulp
density
% solids
50
50
50
10
50
50
20
Temp.
22
50
22
22
22
SO
22
Time
h
2
2
2
2
2
2
2
Ra-arade (nCl/ol
Feed Residue
105
105
105
105
105
105
105
80
76
40
65
85
75
80
Ra-extractton
wtX
25
28
62
38
20
29
24
                                                                                                                                        42
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REMEDIATION OF FORMERLY UTILIZED SITES  REMEDIAL ACTION PROJECT  (FUSRAP)
SITES"
(Presented by:  R.  Atkln,  U.S.  DOE)

    The Office of Remedial Action and Waste Technology of the Department of
Energy currently operates  four  programs:   (1) Formerly Utilized Sites Remedial
Action Project (FUSRAP); (2)  Surplus Facilities Management Program  (SFMP); (3)
UMTRAP; and (4) Grand Junction  Remedial Action Program (WRAP).  The FUSRAP
program Is managed by the  DOE field office In Oakrldge, Tenn.  This
presentation provides a brief history and  general overview of the FUSRAP
Program.

    Established In 1974, one  of FUSRAP's purposes has been to restore sites for
the unrestricted use by the owner.  Until  1984, DOE  followed its own protocols
and procedures for disposal of  uranium-contaminated  soil residues.  However,
DOE Is now following CERCLA protocol and has just begun evaluating  treatment
technologies.  The approach had been to find a permanent disposal site for the
uranium-contaminated residues.   The search was primarily focused In Oregon, but
DOE has had difficulties In accomplishing  the task and therefore now is looking
toward treatment technologies.

    The FUSRAP program primarily consists  of sites utilized during  the
Manhattan Project by the Manhattan Engineering District.  Under this project,
uranium ore was placed In  temporary storage, mostly  In the northeast and
midwest.  The ore was assayed,  sampled, and sent for processing to  six
locations.  After processing, samples went to two different places.  Uranium
oxides were sent to facilities  as a part of the plutonium operation, while
uranium hexafluorides were taken primarily to Oakrldge, Tenn.,  for  enrichment.

    The majority of FUSRAP sites are  located in New  York and New Jersey, with
others In Missouri.  Each  state has a  site manager.  Permanent disposal Is
being sought In each of these states  as a  preferred  method of disposal for the
contaminated residues.

    As a result of a Congressional mandate, five sites were added to FUSRAP
that were not utilized by  the Manhattan project, but that did contain similar
contaminated materials.  The  total  number  of FUSRAP  sites became 29.  Two more
sites are to be added In the  near future.

    Sites were chosen by DOE  headquarters  in Washington and turned  over to the
field office in Oakrldge.   Following characterization and preliminary engineer-
ing, the NEEPA/CERCLA remedial  action process Is begun.  Decontaminated
materials art presently stored  In interim  storage at the site of origin.
Ideally, DOE would like to store the materials at a  permanent disposal site,
but no permanent site currently exists.  Three DOE sites In New Jersey have
been remediated:  Middlesex Sampling  Plant, Maywood, and Wayne.  These sites
have 30,000, 35,000, and 50,000 yd3 of  decontaminated residue 1n vicinity
property Interim storage,  respectively.
                                       43
 RADIOACTIVE MATERIALS EXTRACTION TECHNICAL SESSION:
 ANSWERS
                                                                                                                                                           SELECTED  QUESTIONS AND
 Question 1:


   Response:
 Question 2:
   Response:
Question  3:


  Response:




Question  4:


  Response:



Question 5:


  Response:
 CANMET worked on  Elliot  tailings  removal  in using flotation
 technique.  Can you  address  this  and tell  us of the success?

 (Haque)  - The Elliot tailings  contained  lots of sulflte material,
 mostly pyrlte. Radium precipitates  as RaSOi during the sulfuric
 acid treatment process.   It  will  be possible to concentrate by
 flotation, along  with the  sulflte metals.   My colleague did this
 study and he concentrated  almost  90X of  the radium.   The problem
 came up  of what to do with that 10% solid  concentrate, which had
 high-level radium.   It was looked at in  a  study,  but the results
 were not accepted because of costs.

 What does it cost in  J/yd3 to  put these  soils in  a big pile,
 haul them off, and dump at either a  mine tailing  site or a site
 such as  the one In Utah that Is accepting  this  kind  of thing at
 less than 2.000 pCI/g?

 (Richardson) - We've done some preliminary  cost estimates for
 soil washing and  It comes out  to  be  about SlOO/yd  .   At  a
 number of sites In the United  States, we've  seen costs for
 excavation and transportation  to  be  at $700-900/ydJ.   I  have
 heard S350-400/yd3 for In situ vitrification,  if in  fact you
 can use that for radioactive material.  I'm not sure  what the
 costs are for solidification.

 I  was more curious about the Wayne site and Maywood.slte as  to
 the costs per yard to make the 35,000 and 50,000 yd3  piles?

 (Land)'-  For placing the soil In  Interim storage, the  cost is
 SISO-250/yd3.   The cost  to transport the soil from interim
 storage to an  In-state-permanent disposal site would be  an
 additional  $200-300/yd3.

 Are you finding  Th(230)  migrating  in the groundwater away from
 your FUSRAP  sites?

 (Atkin) - The contamination at  both  the Wayne and Maywood sites
 is  primarily Th(232).  The  answer  is no,  we have not found any
 migration of Th(232)  at  any of  our sites.

 We  have no effective  soil washing  technique  to my  understanding.
 I mean, the fines  do  not wash,  correct?

 (Snodgrass) - We feel  we can  remediate about one-third of the
 site based on our  study.  This  fraction consists of the majority
 of  the larger parts.   The radioactivity becomes concentrated  in
 the finer materials, and for  that  reason you  have to  fall back
 upon excavation, transportation, etc.  So, why do we  use  soil
washing?  Well, if you can remediate  one-third of the  site at
                                                                                                                                           44
-------
rv>
Question 6:





  Response:





Question 7:



  Response:


 Question 8:


  Response:
                     $100/yd3  and  the  rest  at $300/yd3, do you chose that or
                     S300/yd3  for  the  whole site?   I feel you go the soil Mashing
                     route If  It Is  possible at  full-scale, and that Is the next step.

                     What kind of  radioactivity  do  you measure, and does the
                     measurement depend on  the size of the particles?  If you measure
                     gums from a large particle that was crushed up, you would
                     probably  get  a little  wore  gamu radiation.  But, If It was alpha
                     radiation, you would probably  get a  lot more than with beta.

                     (Richardson)  - We were concerned about that  In some of our analy-
                     ses of larger samples. Not  only that, but  from just a statistical
                     analytical problem.  So, we took some 4-4 material and counted  It
                     using gamma ipectroscopy,  then crushed It  and got essentially  the
                     same numbers.

                     You mentioned that you saw less Th(230)  than Ra(226)  after the
                     material  was washed, for all  cases.  Was  this  In  the water or
                     residual  soil?
                                                                  Th(230) was less 1n
(Richardson)  -  It  was  In  the  residual  soil.
the soil  sample than Ra(Z26).

So that indicates  something contrary  to whatever else we've
experienced with respect  to the  solubility of thorium, right?

(Richardson)  -  We  are  measuring  the Th(230) concentration  In
those filtrates now.   As  I  indicated  earlier, the Ra(226)  Is
below 25 pCI/L. One thing  I  want  to  mention, around pH 3.5. the
thorium ion hydrolyzes and  you get a  thorium hydroxide material
that polymerizes and  It becomes  a  very insoluble mess.   It seems
to me, in order to do  some  thorium chemistry with soil, you've
got to be below that  pH.
                                                                                                                                      SECTION 7
                                                                                                                      TECHNICAL  SESSION -  TECHNIQUES/EXPERIENCES
                                                                                                                               FOR ORGANICS EXTRACTION
BIOTROL SOIL HASHING SYSTEMS FOR REMOVAL OF ORGANIC CONTAMINATION AT WOOD
TREATING SITES12
(Presented by:  S. Valine, Blotrol, Inc.)


    Biotrol, Inc. is a commercial treatment services firm that specializes  in
environmental systems to be used In on-slte remediation of organic contamina-
tion.  Blotrol developed a family of microbiology-based treatment systems to
remediate contaminated groundwater, surface water, and soils, as well as
provide effluent pretreatment for process water.  A brief description of two of
these systems follows.

    The Blotrol Soils Treatment System (BSTS) Is a unique and proprietary
physical/microbiological treatment technology for on-site remediation of contam-
inated soils.  The BSTS technology uses soil scrubbing as a volume reduction
step in a mult1-component soil decontamination system.  It Is Ideal for soils
that require excavation for application where other technologies will not
produce timely results.  Large-scale BSTS will have throughputs of 10 ton/h and
will operate on a 24-h/day, 7-day/wk basis.

    Operating on the concept of using water to scrub contaminants from the  soil
particles, the water is subsequently treated using microbiological treatment or
other physical/chemical treatment alternatives, and then the water Is returned
to the soil scrubbing unit for reuse.  The BSTS technology Is generally con-
sidered to be a net consumer of water, thereby eliminating requirements for
significant water discharge during operation.

    Excavated soils are first classified according to size, and oversize
materials are sent through a size reduction and segregation step to maximize
the volume of Materials that can be treated.  The objective in applying the
BSTS technology Is to achieve a "clean* classification and minimize the amount
of residuals that have to be managed over the long-term.

    The soil scrubbing process utilizes a series of steps that Include flota-
tion, attrition, counter-current clarification, filtration, and separation to
remove the desired level of contaminants.  Although the process was originally
developed to remove organic contaminants. It has been determined that inorganic
contaminants can also be removed using this technology.

    The contaminants that are removed by scrubbing Include dissolved as well as
entrained materials, which can then be treated by a variety of strategies.  The
most ideal approach for concentrate disposition Is to recover the materials for
reuse In an existing process at the candidate site.  Other alternatives Include
diverting the concentrate to residuals management (i.e., encapsulation,
solidification) or further treatment.
                                               45
                                                                                                                                                 46
-------
    The contaminants In the soil  fed to the BSTS process are either scrubbed
from the surface of the soil during treatment  or remain absorbed on organic and
clay partlculates, which are separated from the soil  during the washing
process.  Mass balances established that 20K to SOX of the penta from the
contaminated soil was present In  the clarified wash water and fed to the
Btotrol Aqueous Treatment System  (BATS) reactor where It was biologically
degraded.

    The heart of the BATS Is the  bloreactor unit, In which the microbes are
Immobilized as a fixed film.  The units can be based on either aerobic or
anaerobic conditions depending upon the target contaminants.  The BATS receives
contaminated water In a receiving tank where 1t Is conditioned for treatment tn
the bloreactor.  The water Is passed through the bloreactor where the microbes
mineralize and/or metabolize the contaminants  Into harmless constituents
Including carbon dioxide and water.

    The BATS system has the broadest experience base on a variety of contamin-
ated media In wood-treating wastes  Including penta-creosote components.  Other
potential contaminants that are targets to be treated In BATS  Include chlorin-
ated hydrocarbons such as TCE, PCE, and TCA, In addition to PAHs, coal tar
residues, and organic pesticides.   Underground storage tank contaminants such
as  fuels and solvents are attractive candidates for biological treatment using
the BATS units.

    Blotrol has  a field treatablllty demonstration unit available for evalua-
tion of soil at  specific candidate  sites.  Data collected from a treatablllty
demonstration conducted during the  fall of 1987 at a Superfund wood preserving
site In Minnesota are presented  In  Table 9.  Data are segregated by soil type
and test number  and  Include the  soil  feed rate on a dry basis, as well as  the
concentration of penta  tn both the  feed and washed product.  Based on these
Initial  test results, design of  a conwerclal-scale BSTS has been Initiated.
Capital  and operating cost  projections  are continually  Improved as the study
continues.

    A  major application of  the BSTS technology  Is  In volume reduction for
large-scale treatment  projects where  the principal  treatment strategy  Is for
on-slte Incineration.   By  using  volume reduction  prior  to  Incineration,  the
total  cost  of treatment Is  significantly reduced.   In general, the BSTS
technology  total costs  will  fall within the range of $75  to $125/ton depending
upon volume,  soil type,  and contaminant concentration.

     The Blotrol  Aqueous Treatment  System (BATS)  Is  an  engineered system  that
has been designed for continuous operation and discharge  In  the treatment  of
 various types of waters containing organic contaminants.   BATS Is  a complete
 turnkey system containing  all  the  process  equipment and controls necessary to
provide a suitable environment for the bacterial  systems  that  are  the heart of
Blottol's proprietary microbiological  technology.

 EXPERIENCE GAINED WITH A SOIL-DECONTAMINATION SYSTEM IN BERLIN13
 (Presented by:   M.  Nells,  Harbauer, GmbH S Co.  AG)

     The Harbauer extractive soil washing system has been  In operation  since
                                        47
                                                                                                             TABLE 9.  COMPARISON OF PENTACHLOROPHENOL IN FEED AND CLEAN  PRODUCT
                                                                                                                       BSTS  PILOT STUDY - OCTOBER TO NOVEMBER 1987[I2]
Feed
Soil
1





2





3








1/3*
Test no.
4
5
11
12
13
Mean
6
7
8
9
10
Mean
1
2
3
15
16
18
19
20
Mean
17
Dry (Ib/h)
420
285
241
389
214
310
345
463
451
398
442
420
NA
401
396
425
465
433
531
434
441
402
Penta, ppm
NA
795
1.308
1.893
1,997
1,498
152
148
119
120
262
160
229
218
215
206
211
234
208
213
218
723
Clean soil product
penta, ppm
35
34
65
106
US
80
14
8
6
5
17
10
7
NA
18
22
NA
27
29
26
22
53
NA - Not available.
*  - 50:50 mixture.
                                                                                                                                               48
-------
July 1987 at the former Pintsch facility In  Berlin.  The  level of contamination
at the Plntsch site was medlun to extremely  high  In both  the soil and ground
water as the result of refining/recycling of used oils that (n some cases were
contaminated by PCBs,  solvent, and other chemicals.

    The primary pollutant groups found In both  soil and ground water were:
mineral oil. halogenated hydrocarbons, polycycllc aromatic hydrocarbons,
polychlorlnated blphenyls, aromatic hydrocarbons, and phenols.   In addition,
polychlorlnated dlbenzodtoxlne and dtbenzofuran were found.

    In order to control the Immediate danger and  limit the release and  spread
of contamination through dust and air emissions,  as well  as further
contamination of the groundwater, the Senate of Berlin Initiated a cleanup
program In the fall of 1984.  The firm Kemaer/Harbauer was responsible  for  the
majority of the cleanup activities on the site.

    A laboratory-scale unit was used to determine the feasibility of separating
pollutant from soil and subsequently recovering cleaned  soil through separation
and dewaterlng.  Successful results were obtained from the laboratory
demonstration phase between November 1985 and July  1986,  and It  was determined
that a full-scale application was then feasible.  The first unit was built  In
September 1986 and consisted of two baste segments:

o   Mixing of the soil with extractant In a blade washer and subsequent
    extraction by vibration.

o   Material separation and rinsing using a sedimentation tank,  blade washer
    filter band press, and drying beds.

    The  first full-scale  unit  (PB1) proved, as the  laboratory-scale work had
Indicated, that separation  and recovery were possible.   The  particle  size
separation limit  for  this  Initial unit was 130 urn,  which for the high clay
content  soil at the Plntsch site meant up to 40% residual sludge volumes.
Therefore, after  a relatively  short time, the unit  was  extended  to  Include
additional steps  for  the  separation of fine particles.

    These additional  elements  (PB2) Included a multi-step hydrocyclone, which
separated particles down  to 15 urn, and a filter band press  for dewaterlng of
the residual  sludge.   Having  finished the development of the PB2,  a  test run of
10,000 tons was made  over a .3-month period for a variety of soils.

    The 10.000-ton evaluation showed  that additional  refinements In  some areas
could be made  to  Increase cleanup efficiency and operational  safety.   The
current  development state (PB3)  Included the following  changes/additions In
order to address  these parameters:

o  upward current classification to  separate light materials;

o  thickening  and clarification  for  phase separation of the fine range;

o  changed water cycles;  and
                                        49
o   Introduction of additional clarifying technologies and dose possibilities
    for the ensuing process steps.

With these changes, the process was finished) In August.  After an  additional
test period, the process was operational.

    The Harbauer soil washing system Is currently considered  to be among the
best soil washers developed In the FRG.  The heart of the unit Is  a low
frequency vibration step used to Improve cleaning by mechanical action.   A flow
schematic of the Harbauer soil washing facility Is shown In Fig. 3,  with more
detailed explanation that follows.

    The first step in the Harbauer soil washing process Is soil preparation.
Particle sizes > 60 mm are separated out of the stream by a vibrating sieve.
Gravel in the size range 10 mm < x < 60 mm is separated out and washed with a
blade washer before the main soil stream, x < 10 mm enters the vibration unit.

    Harbauer attributes the success of their soil washing plant primarily to
the vibration unit.  In this unit, the soil Is subjected to oscillations using
mechanical energy to dislodge the contaminated fines from the soil  matrix.  The
soil Is mixed with an extractant and passes thorough the vibration unit by a
screw conveyor to which the vibrations are axlally applied.   Because the energy
and residence tine can be carefully controlled, the unit can  handle a wide
variety of pollutants and soil types.  After passing through  the vibration
unit, the cleansed soil is then separated In stepwise fashion with removal  of
particle sizes fro* 10 on down to ZOO urn occurring In the first step by
sedimentation; the second fraction 1s removed down to 20 urn by a series of
hydrocyclones; and the last fraction Is removed down to 15 urn by a flocculatlon
step followed by a filter belt press.  Dewaterlng of the sludge Is done by belt
press, to decrease the volume of residues that must be landfilled.   The amount
of residual sludge is dependent upon the particle size distribution of the
Input material.  For soils processed to date, residual sludge amount Is between
5X-10X of the Input.  The pollutant level of this residual sludge  Is determined
primarily by the solubility of the pollutants present.  Pollutants such as
heavy metals with relatively low solubility result In an enriched  sludge,
whereas organIcs with high solubility such as benzol result In comparatively
low loading of the sludge.

    All the contaminated effluents from soil washing are pumped to the ground
water treatment system on-slte.  The groundwater treatment system  has five main
operations:  dissolved air flotation (OAF), countercurrent stripping, air
stripping, sand filtration, and adsorption (activated carbon  and resin).  The
groundwater treatment facility is full scale, treating 360 •ryh (1,584 gpm).
Unique in Its large capacity, it has been operating since 1984 and Is a NATO/
CCNS Pilot Study demonstration facility.

    Although the Harbauer system Is considered semi batch, because  only some of
the steps are run in batches, it has a throughput of 20 to 40 ton/h.  The unit
cost 1s 250 ON/ton of soil (about S136/ton. not Including the cost of residue
disposal).  Capital costs for the same facility today would be In  the range of
7 to 10 million OH ($4.3 to $6.1 million).  Operational costs and  requirements
                                                                                                                                               50
-------
Figure 3.   Flow schematic of the Harbauer soil wishing process.  [2]
                                 51
for both the Initial  separation and the subsequent separation and dewaterlng of
sludge Increase disproportionately with decreasing particle size.  When
Harbauer began the project, the limit was 63 urn.   They are now Investigating,
under a joint research project with the Ministry  for Research and Technology
and the Land Berlin,  whether It 1s feasible, technically and economically, to
achieve an even finer separation In the range of  10 urn (Fig. 4).

    Although specific data was not presented to support It, It seems that a
combination of low frequency vibration and other  washing techniques 1s effec-
tive at desorblng contaminants from the smaller particles, allowing Harbauer to
separate out a larger proportion of reusable soil.  Harbauer separates soil
particles from 15 urn and greater for a recovery rate of 95%.  Data on the
efficiency of the Harbauer soil washing system on sandy and clayey soils
polluted by various organlcs Is provided In Tables 10 and 11.  The data In
Tables 10 and 11 show similar organic removal efficiencies for sandy and clayey
soils.  However, 1t Is noted that higher residual volumes will be generated by
the clay soil cleaning, adding to the treatment costs.

    Limitations that Harbauer has encountered are typically associated with the
treatment process they employ, such as the costly disposal of carbon containing
PCBs and polyaromatlcs, or problems with the separation efficiency of hydro-
cyclones.  Harbauer has had limited success In treating heavy metals contamina-
tion, but additional techniques are being examined for this purpose.  Harbauer
plans to keep the facility on the Berlin site as a fixed unit (the legality of
this action Is pending) and Is already treating soil brought In  from other
sites.  Three other units, which can be mobile or stationary, are currently In
the planning stages.

ORGANICS REMOVAL BY FROTH FLOTATION AS A SOIL HASHING PROCESS14
(Presented by:  P. Trost, MTA Remedial Resources, Inc.)

    MTA Remedial Resources, Inc. (MTARRI) specializes In onslte detoxification
of hazardous wastes and volume reduction of contaminated soils.  Combined
technology transfers from the mining, metallurgy, and the enhanced oil recovery
fields have resulted In a patented soil wash process.  One of the technologies
involved  In the soil wash process  is froth flotation.

    Froth flotation involves a series of cells, which are linked together by
underflow weir gates to move the slurry from one cell to the other.  Cells can
vary  in size from bench-scale to 3,000 ft3.  Each cell contains  a rotor and a
stator with air Inducted or blown down the center of the shaft,  thereby
creating  large amounts of turbulence and • froth at the top of the water.  The
process is a continuous flow process and not a batch process.

    The Incoming contaminated soil Is preconditioned with a combination of
surfactants and alkaline agents to aid In the removal and separation of the
organic contaminants from the clay and sand.  The soil/water slurry, generally
being approximately 30 wtX solids. Is then pumped as a slurry to the froth
flotation cells.  These cells are equipped with paddle wheels to skim off the
froth that forms at the top of the cell.  Within the froth  Is the contaminant,
water,  surfactant, and minor amounts of clay.  Dependent upon soil mineralogy,
the froth will contain 5-10 wtX of the original soil feedstock.  The clean  soil
passes  from one cell to the next as an underflow; retention time 1n each cell
                                                                                                                                       5Z
-------
                                                                                    TABLE 10.  PERFORMANCE OF THE HARBAUER SOIL WASHING SYSTEM ON SANDY $011(2]
                                                ^     L.
8Q   O  O   Q    O   O   O   O
»   *.  <0   ^    **>r«   —
Pollutant
Total organic! (ng/kg)
Total phenol (mg/kg)
PAH (mg/kg)
Extractable org-Cl
compounds (rag Cl-kg)
PCB (mg/kg)
TABLE 11. PERFORMANCE OF
WITH HIGH CLAY
Pollutant
Total organic* (ng/kg)
Total phtnol (*9/kg)
PAW (mg/kg)
Extract ablt org-Cl
compounds («g Cl-kg)
PCB (mg/kg)
Input Output
5.403 201
US 7
728.4 97.5
90.3 nd
3.2 0.5
THE HARBAUER SOIL WASHING
CONTENT[2]
Input Output
4.440.5 159
165 22.5
947.8 91.4
33.5 nd
11.3 1.3
Removal
efficiency
(*)
96.3
93.9
86.6
100
84.1
SYSTEM ON SOILS
Removal
efficiency
<*)
96.4
86.4
90.4
100
88.3
                                                                                                                           54
                   53
-------
                                                                                                                                             9S
                                                                                                                        a •
                                                                                                                        • ^
                                                                                                                        9 _
1s regulated by adjustment of the weir gates dividing one cell  from the other.
Typically, retention times from S to 30 mln are necessary to achieve the
desired cleanup.  The clean soil, after exiting as a slurry form the cells. Is
then piped over to a standard solid/liquid separation system.  The solid/liquid
separation generally utilizes claHflers followed by a belt filter press to
achieve the desired moisture content.  Water released by the filter press Is
recycled back to the system.  Waste streams coming out of the system Include
the contaminant In the froth and minor water bleed-off.  For soils containing
high concentrations of volatile organic compounds (VOCs) vapor emission
controls are emplaced over the reactor vessel, the froth flotation cells, and
the froth belt filter.  Captured VOCs can then be diverted through activated
carbon or a recovery solvent.  The froth waste stream Is approximately 5-10 wt*
of the original feed material and must be disposed of In a landfill or be
Incinerated.  The water can be recycled back Into the process,  thereby
minimizing water treatment.  Final water cleanup can be achieved by using
carbon adsorption or other suitable means.

    Fig. 5 Is a generalized flowsheet for an organic decontamination plant
using the froth technique.  Fig. 5 Is generally applicable for soils containing
less than 5 wtX of total organic carbon.  HTARRI has, however,  successfully
detoxified sludges (e.g., API separator sludges) containing up to 45* total
organic carbon.  This is accomplished by utilizing a solvent wash step in front
of the flotation section.  Both  the solvent and the recovered oil contained <
2X BS&W, and thus could be recycled to a refinery.  The flotation step then
strips the remaining amounts of  solvent and oil from the soils, thus achieving
the very high removal rates of 98X to 99+%.

    Table 12 shows the results for removal of volatlles from a Superfund site.
As can be seen, the dichlorobenzenes, benzenes, toluenes, xylenes, and styrenes
have high removal efficiencies.  One reason for this high removal rate is due
to the froth flotation cell actually being a very efficient air stripping unit
for solids.  Nass balances of a  volatile contaminant:  (1) in the original soil;
(2) In the water; (3) In the froth; and (4) in the clean tails, show that a
large amount of the volatlles are  Indeed volatilized from the froth to the air.

    For polynuclear aromatlcs and heavy or viscous oils, removal rates gener-
ally will vary  between 98+* to 99+X.  Table 13 shows results of removal  rates
of polynuclear  aromatlcs,  again  from • Superfund site.  The removal rates can
be pushed to the 99+X level  if required by emplacing a  solvent wash step in
front of  the flotation cells.  Table 14 shows the removal of fuel products from
underground storage tanks.  Thus,  the froth flotation  system is capable  of
removing  the volatlles, semlvolatiles, and  fuel products from soils at high
production rates and with  a high degree of removal.

    Equipment for froth flotation  Is available off-the-shelf; thus, there  is
not a necessity to develop new equipment.  This equipment is available to treat
as little as 5  ton/d  to a  maximum of 50,000 ton/d.  The fact that the equipment
has already been developed provides a tremendous time  saving advantage when
applying  this technology to hazardous waste.
S.
                                        55
-------
               TABLE  12.  SOIL WASHING RESULTS FOR VOLATILES[14]

1,1-Dlchloroethene
1,1-Olchloroethane
Trans- 1 , 2-01 chl oroethene
Chloroform
1,2-Dlchloroethane
1 , 1 , 1 -Trlchl oroethane
Tri chl oroethene
1 , 1 , 2-THchloroethane
Benzene
Tetrachl oroethene
Toluene
Chlorobenzene
Ethyl benzene
Styrene
Acetone

Heads (pp«)
43
72
142
99
4,500
5
63
3,700
8
56
30
79
453
280
61
Volatile*
Tails (ppn)
NO
NO
NO
NO
10
NO
0.15
12
NO
0.40
NO
0.90
5.8
7
15*

X Removal
99.9+
99.9+
99.9+
99.9+
99.8
99.9+
99.8
99.7
99.9+
99.3
99.9+
98.9
98.7
97.5
75.4
*  Possible laboratory contamination.
              TABLE 13.  SOIL WASHING RESULTS FOR SEHIVOLATILES[14]


Naphthalene
Fluorene
Phenanthren*
Anthracene »
01-n-Butyl phthalate
Benzo(a)anthracene
Nonadecane
Trldecane
Tetradecane
Creosote

Heads (ppa)
26
28
86
11
13
6.4
6,000
4,000
9,000
25.000
Semlvolatlles
Tails (ppn)
0.032
0.216
0.78
0.08
0.04
0.076
67
34
71
250

X Removal
99.9
99.2
99.1
99.3
99.7
98.8
98.9
99.2
99.2
99.0
                                        57
                                                                                                                  TABLE  14.  SOIL WASHING RESULTS  FOR FUEL PRODUCTS!14]
                                                                                                                                                        Fuel  Products
                                                                                                                                    Heads
                                                                                                                                                        Tails (ppra)
X Removal
2 Methyl 1-Oodecanol
1-Chloro Tetradecane
n-Heptane
n -Octane
n-Nonane
n-Decane
3,8-OlMthyl Undecane
1-Heptadecanol
n -Undecane
Gasoline
Kerosene
Diesel
Benzene
Toluene
11.0
13.1
21.7
165
97.4
128
554
623
203
54,400
54,447
43,900
3
45,690
< 0.001
< 0.001
< 0.001
< 0.001
< 0.04
< 0.04
< 0.04
< 0.04
< 0.04
29
2,119
1,462
0.002
27
99.9+
99.9+
99.9+
99.9+
99.9+
99.9+
99.9+
99.9+
99.9+
99.9
96.1
96.7
99.9
99.9
                                                                                                                                            58
-------
      Process flow rates have been  engineered  for  so<1 washing units as small as
  S ton/d to as large as 860 ton/d.   Both operating and capital cost have been
  determined on a number of private and  Superfund  projects to a ±10X level.
  Depending on the nature of the contaminant,  mineralogy of the sample, volume of
  the material, the degree of cleanup, and  the rate of cleanup, the costs will
  vary from $50 to $180/ton.  Typically, a  SO,000  ton cleanup would cost
  approximately $85 to $100/ton assuming a  Level C protection.  This cost
  Includes operating and capital costs,  disposal of the froth containing the
  contaminant, excavation, backfill, and health and safety.

      HTARRI has evaluated soil washing  systems varying In size from 5  to 860
  ton/d/ and Is currently In the process of designing and constructing  a 50  ton/d
  mobile demonstration unit.  Availability  Is  expected  In 1989-1990.

  THE B.E.S.T. SLUDGE TREATMENT PROCESS15'16
  (Presented by:  0. Austin, Resource Conservation Company)

      Resource Conservation Company (RCC)  developed  and patented  the B.E.S.T.™
  process  in the mid-1970s  as  a means of dewatering  municipal  wastewater
  sludges.  The process was proven to successfully recover  solids high  enough  in
  nutrients to be sold  as animal feed or fertilizer.   The low price of  these
.tr products combined with  the availability of inexpensive disposal alternatives
rv>made commercialization  uneconomical at the time.  The process was not developed
°° further  until  1984 when environmental  legislation  under RCRA escalated
  hazardous waste disposal  costs.  As a result, investigation of  B.E.S.T.™ as
  a  method  for the treatment of oily sludges was  initiated.   After an  Intensive
  market  study,  RCC  felt  that  It could provide a totally  engineered processing
  plant  at  competitive  prices  to process listed and  non-listed oily wastes.

       In  1985, RCC built  its  first  full-scale unit.   This  unit has a  nominal
  capacity of 100  ton/d (wet  throughput) and can handle sludges that  contain up
   to 301 oil  and up  to  40X solids,  without modifications.   Actual throughput,
   however,  will  vary with the  composition and chemistry of the sludge.

       B.E.S.T.™ was designed using modular concepts, which makes the unit
   mobile.  TIhe ability  to move the unit from  site to site enables RCC to contract
   B.E.S.T.™ on  a fee basis.   By owning and operating B.E.S.T.™ units, RCC
   can contract cleanup  work and free customers  from capital expenditures.

       The key to the patented B.E.S.T.™ process  Is the use of one or more of a
   family of aliphatic amtne solvents to effectively break oil-water emulsions and
   thus release bonded water In the sludge.  The aliphatic amines have a unique
   property; cooled below 20°C they become  completely mlsclble with water, but
   upon heating they becooe Immiscible.  To take advantage of this  'solubility"
   property, the B.E.S.T.™ process mixes the  refrigerated amlne  solvent with
   the oily sludges.   The solvent immediately  liquifies the sludge  and turns the
   mixture Into a homogenous solution.   Since  the  temperature  is  kept below the
   solubility line, solids are no longer bonded by the oil/water  emulsion that was
   part of the original  sludge and  are released from the solution.  Once the
   solids are removed, the temperature of the  liquid fraction, which contains the
   oil, water, and solvent, is heated above the solubility point  and the water
   separates from the oil and solvent.   The last step In the process is to remove
   the solvent from the oil using classical  distillation.
                                          59
     In Fig.  6,  the B.E.S.T.™ process flow Is diagrammed.   The sludge Is
 Introduced to the solvent In a mix tank where refrigerated solvent Is agitated
 along with the sludge.   The mixture then Is sent to a solid bowl decanter
 centrifuge used to increase the rate of the solids separation and to Insure
 that subaicron-size particles are removed.   It Is critical to a successful
 operation that the first centrifuge obtain  a very high capture rate and produce
 very clear centrate,  because any carryover  of solids may result In the
 formation of "rig" layers (n the decanter or emulsions in  the oil product
 resulting In degraded oil.   The solid cake  from the first  centrifuge normally
 contains approximately  50 wtX solids.   These solids are sent to a second mixing
 tank,  and the solids  are again washed with  the solvent.   By this time, the oil
 has  been extracted from the solids twice and has been reduced to about 1 wtX.

     The solids  can be washed further by pressing them through a multiple-stage
 countercurrent  extractor, which can reduce  the oil  concentration in the solids
 to less than 0.01X.   If very low oil  levels are not required, the
 countercurrent  extractor may be bypassed.   At this point,  the solids are
 essentially  free of oil  and water and are sent to a second centrifuge where
 they are concentrated to about SO wtX.   This cake is sent  to a dryer, which Is
 a hollow disc Indirect  heater that uses steam as the heating medium.  Since the
 solvent has  a lower heat of vaporization that water, the drying step requires
 less energy  than If water were being evaporated.

     The centrate that leaves the first  centrifuge is essentially free of solids
 and  contains all  the  oil  and water extracted from the raw  sludge.  This cen-
 trate,  which Is still cool,  and therefore In solution with the amlne solvent.
 Is heated In a  series of heat exchanger to  a temperature well  above the solu-
 bility  curve; thus, the  mixture Is In  the Immiscible region.   This two-phase
 stream  Is passed through a  decanter where the lower water  fraction Is separated
 and  sent to  a stripping  column to remove residual  solvent.   The top fraction
 leaving the  decanter  Is  primarily the  solvent containing oil  extracted from the
 raw  sludge.   This  top oil/solvent fraction  Is sent  to a  second stripping column
 where the solvent  Is  recovered and the  oil  Is discharged.

     The overheads  are stripped off as an azeotrope  containing 10 wtX water and
 90 wt*  solvent.  These overheads  are  sent,  along with the  solvent vapors from
 the  dryer, to a condenser from which the condensate Is  sent  to a second
 decanter.  In the decanter,  the bottom water fraction Is  removed and recycled
 through the  water  stripper,  what  Is left Is pure recovered  solvent.   The
 recovered solvent  Is  refrigerated and returned  to the beginning of the problem,
 and  the cycle Is repeated.

     Process  economics for the  B.E.S.T.™ process depend  largely upon  several
 variables  such  as  feed composition, product  requirements, utility costs,  feed
 flowrates, and  volumes,  etc.   The  total  cost  on a wet  feed basis  is  In the
 range of  $50  to $15/ton.
    RCC is currently operating its B.E.S.T.™ System at an abandoned oil
re-refining site.  The B.E.S.T."1 unit installation was completed in July
1986 at Which time waste material was first Introduced into the system.  Thi
B.E.S.T.™ solvent extraction process has proven its ability to make the _.
basic sludge separation as required and therefore indicates that B.E.S.T.™
does Indeed represent a new technology and a real viable alternative.
The
                                                                                                                                                60
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                       19
[SI]  *mji6t|p MOU  ssaaojd
                                                                                   SURFACTANTS FOR WASHING OF PETROLEUM FROM SOIL17
                                                                                   (Presented by:  A.  Abdul,  General Motors  Research  Laboratory)

                                                                                       A bench-scale experiment Mas performed to  study  the  effect of  a  huMlc acid
                                                                                   solution on removing organic contaminants fro* hydrogeologlc systems.   In the
                                                                                   experiment, two coluans containing  aquifer Material  Mere loaded with contam-
                                                                                   Inants.   One col ion Mas leached with Mater while the other Mas leached  with a
                                                                                   27 ppm aqueous  humlc acid solution.  The  contulnants studied were aromatic
                                                                                   hydrocarbons:  benzene, toluene, p-xylene, 3-ethyltoluene, sec-butylbenzene,
                                                                                   and 1,2,4,5-tetramethylbenzene.

                                                                                       Results of  adsorption breakthrough curves  for  the Migration of the  six con-
                                                                                   taminants through the column showed that  the relative concentration  (C_/C|)
                                                                                   Increased with  an Increase In  the number  of washings. As expected,  compounds
                                                                                   Mlth a higher Mater solubility Mere adsorbed by the  aquifer material  In fewer
                                                                                   washings than compounds with lower  water  solubilities.  Washings to  load the
                                                                                   column Mere continued until all contaminants had a relative concentration of
                                                                                   1.0.

                                                                                       The mass of contaminants retained  by  the aquifer material versus the number
                                                                                   of washings Is  shown In Fig.  7.  Data  of  all the contaminants for  both  Mashing
                                                                                   with water or humlc acid solution are  plotted.  It can be seen that  Mashing
                                                                                   with the humlc  acid solution enhanced  the migration  of the contaminant  from
                                                                                   aquifer material  to solution  after  a number of washings  for a few  of the
                                                                                   contaminants.  With fewer washings, the humlc  acid solution did not  have as
                                                                                   noticeable of an  effect on the release of contaminants from the aquifer
                                                                                   material.

                                                                                       As can be seen In Table 15, Mashing with a humlc acid solution was
                                                                                   effective 1n enhancing the removal  of  some of  the  contaminants.  The humlc acid
                                                                                   solution did not  help contaminant  removal of benzene or  toluene, yet Mashing
                                                                                   3-ethylbenzene with the solution  showed a 40%  Improvement over washing  Mlth
                                                                                   Mater alone.

                                                                                       From this study, washing with  a 27 ppm humlc acid solution was found to
                                                                                   Improve the removal of some organic compounds  from aquifer material. Addi-
                                                                                   tional research Is needed In  such  areas as the hydrophoblclty of the humlc
                                                                                   acid, the pH of the pore Mater, the aquifer material organic carbon  content,
                                                                                   and the Impact of the humlc acid on the environment.

                                                                                   EPA SOIL WASHING TECHNOLOGY OVERVIEW  - GOOD ECONOMIC SENSE
                                                                                   (Presented by:   R. Traver, EPA/RCB)

                                                                                       This presentation focused on  four  papers describing  current efforts by the
                                                                                   U.S. EPA on soil  wishing technologies. These  papers are:  (1) Mobile System
                                                                                   for Extracting Spilled Hazardous Materials from Excavated Soils;  (2) Inves-
                                                                                   tigation of Feedstock Preparation  and  Handling for Mobile Onslte Treatment
                                                                                   Technologies; (3) Results of  Treatment Evaluations of Contaminated Soil; and
                                                                                   (4) Superfund Standard Analytical Reference Matrix Preparation and Results of
                                                                                   Physical Soils Washing Experiments. Summaries of  these  papers are presented
                                                                                   below.
                                                                                                                          62
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                                   Washing with Humlc Acid
                                            Pora Volume
                                                  430
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   Mobile-System for Extracting Spilled Hazardous Materials from Excavated
   Soils18

       A technique was evaluated for the scrubbing or cleansing of excavated soils
   contaminated by spilled or released hazardous substances.  Laboratory tests
   were conducted with three separate pollutants (phenol, arsenic trloxlde, and
   PCBs) and  two soils of significantly different character (sand/gravel/stlt/clay
   and organic loan).

       The tests  showed  that scrubbing of excavated soil onstte Is an efficient
    approach for  freeing  soils of certain contaminants, but that the effectiveness
   depends on the  washing  fluid  (water and  additives) and on the soil composition
    and particle-size distribution.   Based on the test results, a full-scale
    field-use, prototype  system was  designed, engineered, fabricated, assembled,
    and briefly tested under conditions where large  (>2.5 cm) objects were  removed
    by a bar screen.   The unit  Is now ready  for field demonstrations.

        The system Includes two major soil  scrubbing components:  (1)  a water-knife
    stripping and soaking unit  of novel  design  for disintegrating  the soil  matrix
    and solublUzIng the contaminant from the  larger particles  (>2  mm) and (2)  an
:*:  existing  but re-engineered four-stage countercurrent extractor for freeing  the
t_>  contaminants from smaller particles (>2 mn).  The processing rate of the system
    Is 2.3  to 3.8 nrYh (4 to 5,ydJ/h), though the water-knife unit (used alone)
    can process 11.5 to  13.5 m3/h (15 to 18 yd3/h).  The complete system
    requires  auxiliary equipment, such as the EPA-ORD physical/ chemical treatment
    trailer,  to process  the wastewater for recycling.  Under some circumstances,
    provision must be made to confine and treat released gases and mists.
    Treatment residues consist of skimlngs from froth flotation, fine particles
    discharged with  the  used washing  fluids, and spent carbon.  The principal
    limiting  constraint  on the treliability of  soils Is clay content (high
    weight-percent),  since breaking down and efficiently treating consolidated
    clays  is  Impractical or  not  economically attractive.  Host Inorganic compounds,
     almost all water soluble or  readily oxidizable organic chemicals, and  some
     partially misc1b1e-1n-water  organics can be treated with water or water plus an
     additive.

         During limited laboratory extraction tests, phenol was very efficiently
     removed  from both organic  and inorganic soils,  whereas  PCBs and  arsenic clung
     more tenaciously to the soils and were  released less readily  into the  washing
     fluids.  The extent to which the system has practical  cost-effective utility in
     a particular situation cannot bo determined until preliminary  bench-scale
     laboratory work has been performed and acceptable Units of  residual concentra-
     tions  In the washed soil are adopted,  laboratory tests show that soil  scrubbing
     has the  capability  of vastly speeding up  the release of chemicals from soils,  a
     process  that occurs very slowly under natural  leaching conditions.

         The  following conclusions  can be drawn from the work carried out during
     this  program:

      1.  Spill-contaminated  soils can be excavated and treated onsite using
         extraction  with water or aqueous solutions for many pollutants  that are
          frequently  encountered  In  such situations.
                                             65
 2.  A system capable of decontaminating 2.3-3.8 m3/h (3-5 yd3/h) of soil  Is
     available for field testing by EPA.
                                                                   i
 3.  Water knives function as a compact, efficient and economical means of
     achieving effective contact between contaminated soil particles and
     extractant.

 4.  Countercurrent extraction Is an effective process for removing certain
     adsorbed contaminants from soils.  The device preferred for separating the
     extracted solids from the extractant Is the hydrocyclone.

 5.  Soil  characteristics. In particular particle size distribution, organic
     content, pH, and Ion-exchange, are Important factors In the removal or
     retention of contaminants.

 6.  In addition to the actual percentage of the contaminant removed, the
     allowable level  of pollutant remaining In the soil  1s an Important factor
     In determining when adequate decontamination has been achieved, since the
     final  residual concentration affects the options available for disposal of
     the cleansed solids.

     Based  on the observations made during this investigation, several  sugges-
 tions are  offered for future work.

 1.  Laboratory screening tests should be performed on a wide range of typical
     compounds and mixtures  encountered In hazardous substance spill  and release
     situations to ensure that appropriately high levels of decontamination can
     be achieved with the aqueous scrubbing process.

 2.  The results of this study apply primarily to spill  situations.   Contamin-
     ated soils found at waste disposal  sites may exhibit different  extraction
     characteristics  because  of the extended soil/contaminant contact time,
     weathering,  and  1n situ  reactions.   Studies  are  needed  to establish whether
     and to what extent these factors  affect the  decontamination process.

 3.   Other extractant solutions  should  be evaluated to determine whether the
     efficiency of the process can  be  improved without damaging  the equipment  or
     Increasing the hazards to which the  workers  are  exposed.

 4.   A wider  rang* of soils should  be examined to determine what changes In  the
     system are practical  to  better cleans*  soils with characteristics  (e.g.,
     greater  coheslveness  and adsorptlve  properties of clay or silt-rich soils)
     that differ  significantly from those of  the soils already tested.

 Investigation  of Feedstock Preparation and Handling  for Mobile  Onsite Treatment
 Technologies"

     In order to destroy contaminants or reduce the hazardous levels of  any
contaminated material, the treatment system selected must receive a feedstock
with a predetermined range of physical/chemical characteristics  to ensure
reliable treatment efficiencies and cost effectiveness.  The types of
contaminated materials normally Identified and discussed in remedial
 Investigation/feasibility study (RI/FS) reports are primarily materials such  as
soils, sludges, and liquids.   The debris component Is not addressed unless the
                                                                                                                                              66
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  primary contaminated matrix  (s  a mixture of materials (I.e., building
  demolition debris  or sanitary landfill wastes, such as household trash and
  garbage).

      A review of numerous  Records of Decision  (ROOs) and RI/FSs shows a lack of
  site-specific data quantifying  and qualifying Superfund debris.  Few If any
  ROOs or RI/FSs factor Into their discussions of various recommended mobile
  onslte technologies the operational considerations of handling, segregating,
  sizing, site excavation,  and feedstock delivery.  Performance of an engineering
  and economic evaluation of the  types  of debris and their Impacts on the various
  technologies under consideration Is critical  If any fora of onslte treatment Is
  ever to be successfully executed.

      The six onslte technologies under review  Include:  Incineration, low tem-
  perature desorptlon, chemical treatment  (KPEG), solidification/stabilization,
  physical treatment (soils washing), and biological degradation.  Each technol-
  ogy requires that  the feedstock material be delivered with predetermined
  consistencies so that the selected treatment  hardware can function and perform
  reliably In order  to efficiently and  cost-effectively destroy the contaminants
  of Interest or reduce their  hazardous levels.  To accomplish this task, the
  contaminated material, which may be  in the form of soil, sludge, liquid, or
  debris, must be prepared  by  either of the  following means:
Or
*-°o   Physical preprocessing of oversize material (e.g., crushing, shredding,
1X1    screening, separation, dewatering, etc).

  o   Chemical preconditioning,  such as neutralization or reduction/oxidation.

      A preliminary  assessment of each  of  the  six onslte treatment technologies
  was conducted to determine the  maximum size  of debris and material that could
  be allowed to undergo the treatment  process.  The maximum debris size for each
  technology based on this  preliminary assessment Is  Indicated in Table 16.

                    TABLE 16.  MAXIMUM DEBRIS  SIZE/TECHNOLOGY[19]
  Maximum debris size
     Technology
   1-2  Inches

   1  Inch

   6  Inches

   1/4  Inch

   2  Inches

   6  inches
Biological  degradation

Chemical treatment (KPEG)

Incineration

Low temperature desorptlon

Physical treatment (sot) washing)

Solidification/stabilization
                                         67
    In addition to debris removal, feedstock preparation may  also  Include other
preparatory steps for the treatment process to be effective.   Feedstock
requirements will vary with each technology and contaminant under
consideration.  Feedstock factors that must be identified  and evaluated when
considering one of the six technologies Include:

o   contaminant concentrations
o   pH adjustment
o   moisture content
o   oxidation/reduction status
o   temperature range
o   salt concentrations
o   any special requirements

Recommendations by the authors are listed below:

    Recommendations for Proposed RulemakJno

    1.   Classify material as debris  based on the  size requirements of the
         recommended technology.

    2.   Segregate debris for decontamination, recycling and  reuse,
         incineration, treatment, or  land disposal.

    3.   Treat each site debris  situation on a case-by-case basis  with the
         disposal determination  made  by  the  local  regulatory  authority (I.e.,
         county, state, or EPA Region).

    Recommendations for Immediate Research Meeds

    I.   Modify  reporting and site  investigations  under RI/FS programs to
         quantify and qualify the amounts and  forms  of debris on both a percent
         weight  and volume basis.

    2.   Conduct an engineering  review and evaluation of technologies
         applicable for segregation of soil  and debris for further processing
         and  feedstock preparation.

Results of Treatment Evaluations of Contaminated  Soils*1*

    Under  Phase  I of EPA's research program, which was conducted from April to
November 1987, a surrogate soil  containing a wide range of chemical contamin-
ants  typically occurring  at  Superfund sites  was  prepared and  subjected to
bench- or  pilot-scale performance evaluations  using  the following treatment
technologies:   (1) physical  separation/volume  reduction (soil washing);  (2)
chemical treatment  (specifically, KPEG);  (3) thermal desorptlon; (4) Inciner-
ation; and (5)  stabilization/fixation.  This report  covers the formulation and
development of the surrogate soil;  it also highlights the results of the five
treatment  evaluations.

    The basic formula  for the SARM  (Synthetic  Analytical Reference Matrix) soil
surrogate  was determined  from an extensive review of 86 Records of Decision
(ROOs) and a  parallel  Independent study  of the composition of eastern

                                        68
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    United States soils.   The results of both sets of data lead  to almost  the same
    formula:   30% by volume of clay (montmorlMontte  and kiollnHe), 25X silt, 20X
    sand, ZOX topsoll,  and SX gravel.  These components were assembled, air-dried,
    and mixed together  In two 15,000-lb batches In a  standard truck-mounted cement
    mixer.
        A list of target  contaminant compounds was developed that  represented the
    most frequently occurring hazardous compounds at  Superfund sites, and  that also
    provided a challenging test matrix for  all five treatment technologies.  The
    final list of chemical contaminants chosen for the SAW studies Is as  follows:
Jr
UO
UJ
                                                           Semtvolatlle organic*
                                                           Anthracene
                                                           Pentachlorophenol
                                                           B1s(2-ethylhexyl)phthalate
    Volatile oroanlcs             Metals

    Ethylbenzene                  Lead
    Xylene                        Zinc
    1,2-Dlchloroethane           Cadmium
    Tetrachloroethylene          Arsenic
    Acetone                       Copper
    Chlorobenzene                 Chromium
    Styrene                       Nickel

    The  final step In  this  research process was  to examine the levels  at which
these chemicals have been found at Superfund sites and to select concentrations
that would be representative  of contaminated soils and debris.  The EPA
compiled average and maximum  concentrations of each selected  chemical  and from
these data, devised target  contaminant concentrations for formulating  four
different  SARH preparations:
SARM 1:   High levels of organic* (20,800 ppm volatlles plus  10,000 ppm
          serai volatile*) and low levels of metals (1,000 ppm  total metals).

SARM 2:   Low levels of organic* (2.080 ppm volatlles plus 1,000 ppm seml-
          volatlles) and low levels of metals (1,000 ppm total metals).

SARM 3:   Low levels of organic* (2,080 ppm volatlles plus 1,000 ppm seml-
          volatlles) and high  levels of metals (50,000 ppm total metals).

SARM 4:   High levels of organic* (20,800 ppm volatlles plus  10,000 ppm seml-
          volatlles) and high  levels of metals (50.000 ppm total metals).

    Samples of  each SARM  preparation were treated In bench-  or pilot-scale
experiments utilizing one of the five  treatment  technologies.  A rank-order
suiwary of the  effectiveness  of each treatment  technology on the four SARMs  Is
presented In Table 17.

Suoerfund Standard Analytical Reference  Matrix  Preparation  ind Results of
Physical Soils  Washing Experiments"

     This report covers segments of  Phase I related to development of  a
surrogate soil  and experimental bench-scale tests on the potential
effectiveness of soil washing as described In the previous  section  ('Results  of
Treatment Evaluations of  Contaminated  Soil").
                                                69
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                                                                                                                                                                 (low ortonlco. low ootiti)
Inelnorotlon
toll woohlnf » 2 BO Motor
CMBlcol trootBOnt OCa no. 1
tall waolilni » 2 OB curfoctont
toll uaohlnt 2 OB to 250 uo ourfoctont
tall waohlnt 2 OB to 250 uo Motor
Low toBporotura thomol tiinrt at 3M°r
law taaporoturo tharBil dooorb ot 550°r
tolldlflcotlon • kiln duot 28 d*ro
CMBlcol trootBont fti no. 2

HBlvalotlloo
>99.99       Inelnorotlon                             »99.9B
>99.99       tall uaaMna • oil fraction • wotor          >99.9
 99.94       tall uaahlna - all froctlono • choloto          99.7
 99.82       tall Moahlnt • oil fraetlom - ourfoctont       99.7
 99.82       Solidification kiln duot - 28 doyo             99.7
 99.8        low toanoroturo tharBol dooorb at 150°r         98.7
 99.7*       CMalcal trootaant oca toot no. t             98.2
 99.78       tolldlflcotlon lla»/fly ooh                  97.0
 98.5        CMBlcol trootBont mt no. 2                 96.J
 98.5        low tooporoturo thonool ot 500ef               96.17

            loBl¥alotlloo
Inelnorotlon
toll Hoorilni • 2 ojo ourfoctont
toll unMno • 2 OB Motor
a>o»leol troouont Ofa no. 2
Choaleol trootom ma no. 1
Lou tocporotur* thonol Jiurt ot
toll nooklnl 2 •• to 2SO (• ourfoctont
SolIdl(lotIon llao/flr ooh oirfoctvit
tolldlflcotlen kiln duot
toll voXilr*; <2SO w Motor

Hotolo

toll woonlni • 2 OB Motor
toll uooklna » 2 mi ourfactint
toll woohlna 2 OM to 250 uo Motor
toll Mooklnf 2 •• to 250 !• «urfoctont
talldlflcotlon llo/flr ooh - 28 doyo
talldlflcotlan kiln duot • 28 doy»
Inelnorotlon
»99.»a       Inclnorotlan                             »99.»7
>99.         toll Moohlni » 2 mt Motor                    91.9
>98.         toll Moohlno • 2 •» ourfoctont                9).*
 97.         tall MOohlno • 2 •» cnoloto                  90.t
 9).         IOM toovoroturo thonal dooorb ot J?0°F         88.7}
 9*.         CMdcol troonont Ota toot no. I             8).8
 82.         tall MOoMm 2 •• to 250 uo ourfoctont          a7.]
 80.         tall MOOklm 2 mt to 250 uo Motor              22.0
 80.2        tall Moanlno 2 o» to 250 uo cnoloto            17. J
 19.7        ONBricol trootuont OCa no. 2                 12.)

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 92.         toll Mooklna • 2 •• Motor                   >94.7
 91.         toll MoKlInf • 2 •» cnoloto                  9!.9
 81.         tall Mooklm • 2 «o ourfoetont                91.7
 75.         tall Moohlnt 2 m to 250 .         tall Mooklna 2 «o to 250 uo Motor              82.7
 58.         Inelnorotlon                              M J
            OMjorfcol troomont Oft no. 1                 )9.i
                                                                                                                                                                (continued)
                                                                                                                                                              70
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       toll nooklnt 2 OB to 230 uo dioloto
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       toll Mohlnf t mi to 250 uo Mtor
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 99.»       toll MOliln) » 2 o» Mtor                   >99.o

 99.1       loll HOOklni • 2 mt dwloto                 >99.«
 9>.I       toll KOOkln) • 2 mm lurfoctont               >W.9

 99.0       toll yo>lilr( 2 M to 250 uo wHoetint         >99.r
 99.r
 97.*       tell yoohlm 2 •• to 290 iBHotor            >99.7
 91.2       Oiolcol traonom *ftt no. 2                98.1
 92.0       tolldlflotlon kiln duot • JS doyo            95.)
 86.7       toll voohi^ «250 uo choloto                81.8


           toorfvolltllo*


 99.6       Soil uoohlng • J mm wrfoetmt               >W.I
 99.0       Soil MOhlno • I mm dioloto                 97.8
>9«.»       OMBlcol trootoom 0(0 no. t                9o.2
>9t.S       Owileol trootoanl Ott no. I                92.9
           tolldlflcotlon lloa/fly >oh - 2S doyo         17.9

           toll MMIni I « to OO at cntloto           K.3
           toll nooklni 2 oio to 2JO in ourtoetont         J9.4
           tolldlflcitlen kiln duot • 21 doyo            a.]


           Kotoll


 98.*       toll tMUitn) • 2 mm ourfoctont               98.4
 98.4       toll MlJilnl • 2 «o dwloto                 98.1
 98.0       toll HooMnt • 2 mm Mtor                   97.1

 M.4       toll MMm t tm to 230 !• ourtoetont         91.8

 82.3       toll uomlnt 2 OB to 2M <• Mtor            90.7
 71.2       tolldlflcotlon lloa/fly mti                 73.9

 73.2       tolldlflcotlon kiln duit                   60.3
 4«.4
         loMd on totol Moto onolyooo.
    The  soil  washing results appear to  support the basic assumptions underlying
the volume-reduction approach to site rened1at1on--that a significant fraction
of the contaminants In  contaminated soils are attached to the smaller-sized
particles or fines (I.e.,  silt, humus,  and clay) and  that the coarse material
can be cleaned and returned to the site by physically washing and separating  It
from the fines.  The data  Indicate that water alone can efficiently remove a
significant portion of  the contamination from the >2  nm soil fraction.
Contaminant removal from the middle (2  mm to 250 urn)  soil fraction and the fine
(<2SO urn) soil fraction, however, can be generally enhanced by chelant and
surfactant solutions.   Addition of a chelant to the wash solution can Improve
metal reduction efficiencies for both the medium and  small particle size
fractions.  Addition of a  surfactant to the wash solution can lead to higher
organic  removals (compared with the water wash) from  the fine particles.   In
general, water appears  to  be more effective In mobilizing the organlcs Into
solution than In mobilizing the metals.

    In the preliminary  bench-scale experiments. It was determined that the
surrogate soil was approximately 13 wt% coarse material (I.e., >2 mm), 29 wtx
medium-grained material (250 urn to 2 mm), and 58 wtx  fines (<250 urn).  At  least
a 13 wtx reduction of contaminated material with a water wash alone was
achieved.  Addition of  a chelant solution resulted  In a 42 wtx reduction of the
metals-contaminated surrogate soil, and use of the chelant and surfactant
solutions resulted In lower metals and  organlcs contamination, respectively,  In
the fine particles.

    The  mix of contaminants In Superfund soils often  lends Itself to an
extraction or washing treatment technology such as that demonstrated In this
study.   Although promising results have already been  achieved at the pilot
scale at a number of lead-contaminated  Superfund sites, additional research is
needed to demonstrate the cost-effectiveness of soil  washing for full-scale
treatment of a wide range of metals- and organics-contaminated soils.  Specifi-
cally, most of the research conducted to date has Involved demonstration of the
operation of various pieces of equipment for pretreatment and extraction of the
contaminants from the soil and for posttreatment of the extractant.  The
effective separation of the wash solution froej the soil, the recycling of  the
regenerated wash solution, and the concentration/destruction of  the contamin-
ants, however, havt not been demonstrated at a large-scale pilot facility.  The
following is a listing  of areas In which future work  Is needed with respect to
the development of soil washing as a full-scale, viable treatment option for
Superfund soils:
                                                                                                           1.
                                                                    Laboratory feasibility studies  for evaluating removal of contaminants from
                                                                    the water.
                                                                                                           2.  Laboratory-scale  physical soil washing studies  using actual Superfund soils
                                                                                                               containing a mix  of metal and organic contamination.

                                                                                                           3.  Evaluation of sequential wash solutions for reducing combined  organic and
                                                                                                               metal  contamination.

                                                                                                           4.  Additional pilot-scale studies on  the use of the  EPA Mobile Soil  Hashing
                                                                                                               System.
                                                  71
                                                                                                                                                     72
-------
4=-
OJ
        5.   Bench-scale feasibility  studies evaluating stabilization/solidification
            effectiveness as a treatment train option for the concentrated fines
            remaining  after soil washing.

        6.   Evaluation of feedstock  preparation methods for the EPA Mobile Soil Washing
            Syste*.

        ORGANIC EXTRACTION TECHNICAL SESSION:  SELECTED QUESTIONS AND ANSWERS
Question 1:




  Response:


Question 2:






  Response:





Question 3:


  Response:




Question 4:


  Response:







Question 5:


  Response:
Relative to your 1n situ device,  do  you  have  any  Information  on
the particle size distribution or the mlneralogteal  analysis  of
the materials that you washed?  You  mentioned It  was sand,  but
you didn't go Into details.

(Abdul) - The aquifer material was prescreened to fall  In the
grain size range of 125-250 urn.

Looking at the results you presented on  the humlc acid  extraction
technique, your conclusions were that the technique  appeared
viable for improving pump-and-treat-type aquifer  restoration.
Are you confident that the data you  have come up  with shows that
kind of technique Is really viable?

(Abdul) - I believe that the conclusions adequately  summarize the
observations from the results.  Viability Is  a relative thing;
what may be viable from the perspective  of excavation and washing
should not be the same yardstick to  evaluate  the  viability of an
aquifer system.

What Is the approximate cost and availability of  the humlc acid
on a large scale?

(Abdul) - Humlc acids are primarily  obtained  from peat.  They're
extracted as an alkaline agent usually around a pH 10.   The
typical soil has about 5% to 10* humlc acid,  so they are
Infinitely available.

You stated clays were not a problem  with your system (froth
flotation), could you elaborate on that?

(Trost) - That statement was based on a  number of samples we
worked at that had the clay content  In excess of  SOX of the total
solids.  By adjusting the chemistry  In the froth  flotation cell.
In addition to the actual physical operating  parameters of the
air and the rotation speed of the stator, we  were able  to
suppress the clay so It would not come off In the froth.
                                                                                                                                                SECTION 8
                                                                                                                        SUMMARY AND ROUNOTABLE DISCUSSION PERIOD
    The summary and roundtable discussion period was a forum for voicing
problems and concerns regarding workshops of this kind.

    The 4S-m1nute questlon-and-answer periods at the end of the technical
sessions were critiqued.  They were meant to encourage questions that were not
solely related to the speaker's presentation, but were related to the specific
overall technological area of metals, organic*, etc.  This would result  In
Interaction between all parties, rather than just questioning of the
presenter.  This goal was only half achieved, with most questions being
directed to a particular Item of the presenter's topic.  One reason for  the  low
level of Interaction night be the large diversity of Interests represented at
the seminar.  Several suggestions were given to Increase further discussion.

    One suggestion was for the large group of conference attendees to break  up
into smaller, separate working groups or "committees." This would allow  for  the
discussion of many topics in smaller settings, enabling someone to choose .a
specific area of Interest.  These topics might consist of techniques or
particular remedial problems.  Some topics mentioned Included:
analytical methods, acceptable levels of cleanup, analysis of lessons learned,
feedstock preparation, or comprehensive review of commercial techniques.  These
working groups would then reconvene and report their findings and conclusions
to one another.

    Another possibility is the provision of an informal gathering place  for
discussion to continue after the presentations and question/answer period.   A
variation on this Idea would be to allow a period following each presentation
for specific questions addressed to the current speaker, while having 30minutes
set aside later to provide a forum of general discussion.

    Several recommendations were given on subjects that needed further atten-
tion for future presentations.  One hope was that there would be more case
studies presented so actual performance of treatment systems could be
addressedd.  A standard set of Information might be required of all
technologies presented so that they could be evaluated on the same basis.  This
Information set would Include cost per cubic yard of soil treated, removal
efficiencies of certain contaminants, range of treatment applicability,  time or
material requirements for remediation, the mineralogy and soil size
distribution of samples studied, and the characteristics and disposal methods
of the concentrated wastes and sludges coming from the treatment processes.
                      So it went with the underflow and  the clean soil.
                      removal percent from that  clay component?
                                                   What was  the
                      They met the client's goals,  which would be  In excess of 90X.
                                               73
                                                                                                                                                   74
-------
                                      REFERENCES
   1.  Raghavan,  R.,  O.K.  Dletz,  and  E.  Coles.  Cleaning Excavated Soil Using
       Extraction Agents:   A State-of-the-Art Review.   EPA Contract No.68-03-3255,
       U.S. Environmental  Protection  Agency, Cincinnati. Ohio,  1989.

   2.  Nunno, T.J.,  and J.A. Hyman.   Assessment of  International Technologies  for
       Superfund Applications - Technology Review and  Trip Report Results.   EPA
       Report No.540/2-88/003,  U.S. Environmental Protection Agency, Risk
       Reduction Engineering Laboratory, Cincinnati, Ohio.  1988.
   3.
   4.
.tr
OJ
ON
    5.
Lymin, U., Dr.  "K0c>  The Unconstant Constant".  Conference  slides  from
the Workshop on Extractive Treatment of  Excavated  Soil,  Edison, N.J.
December 1-2, 1988.  Sponsored by the U.S.  Environmental  Protection Agency,
Risk Reduction Engineering Laboratory.
    6.
    7.
    9.
Griffiths, R.  Case Histories for Underground Storage  Tanks.   Taped
proceedings from the Workshop on Extractive Treatment  of Excavated Soil,
Edison, N.J.  December 1-2, 1988.   Sponsored by the U.S.  Environmental
Protection Agency, Risk Reduction Engineering Laboratory.

Esposlto, P.  Characterization of RCRA/CERCLA Sites with Contaminated
Soil.  Conference slides from the Workshop on Extractive Treatment of
Excavated Soil, Edison, N.J.  December 1-2. 1988.  Sponsored by the  U.S.
Environmental Protection Agency, Risk Reduction Engineering Laboratory.

Schmidt, U.  Hydrometallurglcal Treatment of Soil. Conference handout from
the Workshop on Extractive Treatment of Excavated Soil,  Edison, N.J.  Decem-
ber 1-2, 1988.   Sponsored by the U.S. Environmental  Protection Agency,
Risk Reduction Engineering Laboratory.

EvangelIsta, R.A., and A.P. Zowntr.  Lead Extraction  from Excavated  Soil.
Conference  handout from the Workshop on Extractive Treatment of Excavated
Soil.  Edison, N.J.  December 1-2, 1988.   Sponsored by the U.S. Environ-
mental  Protection Agency, Risk Reduction Engineering  Laboratory.

Krlshnan, E.R., and W.F. Kemner.  Innovative Electromenbrant Process for
Recovery of Lead  from Contaminated Soils.  Conference handout from the
Workshop on Extractive Treatment of Excavated Soil, Edison, N.J.  December
 1-2,  1988.   Sponsored by  the U.S. Environmental Protection Agency,  Risk
Reduction Engineering Laboratory.

Richardson, W.  Soil  Washing and Chemical  Extraction of Radtonucltdes.
Taped  proceedings  from the Workshop on Extractive Treatment of Excavated
Soil.  Edison. N.J.  December 1-2, 1988.  Sponsored by the U.S.
Environmental Protection Agency, Risk Reduction Engineering Laboratory.
                                           75
                                                                                                 10.  Hague, K.E., Or.  Radium  Removal  from a Contaminated Soil.  Conference
                                                                                                      handout  from the Workshop on  Extractive Treatment of Excavated Soil,
                                                                                                      Edison,  N.J.  December  1-2, 1988.   Sponsored by the U.S. Environmental
                                                                                                      Protection Agency, Risk Reduction  Engineering Laboratory.

                                                                                                 11.  Atkln, R.  Remediation  of Formerly Utilized Sites Remedial Action Project
                                                                                                      (FUSRAP) Sites.  Taped  proceedings from the Workshop on Extractive
                                                                                                      Treatment of Excavated  Soil,  Edison,  N.J.   December 1-2, 1988.  Sponsored
                                                                                                      by the U.S. Environmental Protection  Agency, Risk Reduction Engineering
                                                                                                      Laboratory.
                                                                                                         12.   Pflug,  A.D.   Abstract of Treatment Technologies.
                                                                                                              Minn.   Undated.
                                                                                                                                                         Blotrol, Inc., Chaska,
                                                                                                         13.
                                                                                                         14.
                                                                                                         IS.
                                                                                                         16.
                                                                                                         17.
                                                                                                         18.
Nells, M.  Harbauer Soil Cleaning System.  Conference  handout from the
Workshop on Extractive Treatment of Excavated  Soil,  Edison,  N.J.   Oecem-
berl-2, 1988.  Sponsored by the U.S. Environmental  Protection Agency,  Risk
Reduction Engineering Laboratory.

Trost, P.8., Dr.. and Dr. R.S. Rlckard.  Onslte  Soil Washing - A Low Cost
Alternative.  In:  ADPA, Los Angeles, Cal.   April  29,  1987.

Burruel, J.A., et al.  The B.E.S.T.™ Sludge Treatment Process:  An
Innovative Alternative Used at a Superfund Site.   In:   Proceedings of 7th
Conference on the Management of Uncontrolled Hazardous Waste Sites.
Washington, D.C.  December 1-3, 1986.

Austin, O.A.  The B.E.S.T.™ Solvent Extraction  Process for  Removing
Hydrocarbons from Soils and Sediments.  Conference slides  and handouts
from the Workshop on Extractive Treatment of Excavated Soil,  Edison, N.J.
Oecem- ber 1-2, 1988.  Sponsored by the U.S. Environmental Protection
Agency, Risk Reduction Engineering Laboratory.

Abdul, A.S., T.L. Gibson, and D.N. Ral.  Use of  Humlc  Acid Solution to
Remove Organic Contaminants from Hydrogeologlc Systems.  Conference slides
and taped proceedings from the Workshop on Extractive  Treatment of Exca-
vated Soil, Edison, N.J.  December 1-2. 1988.  Sponsored by  the U.S.
Environmental Protection Agency, Risk Reduction  Engineering  Laboratory.

Scholz, R., and J. Mllanowskl.  Mobile System  for  Extracting Spilled
Hazardous Materials from Excavated Soils.  EPA Report  No.600/52-83-100.
U.S. Environmental Protection Agency, Office of  Research and Development,
Cincinnati, Ohio.  December 1983.
                                                                                                         19.   Beers,  W.F.   Investigation of Feedstock Preparation and Handling for
                                                                                                              Mobile  Onslte Treatment Technologies.  Draft Report.   EPA Contract
                                                                                                             •No.68-03-3450.   U.S.  Environmental Protection Agency,  Risk Reduction
                                                                                                              Engineering  Laboratory, Cincinnati, Ohio.  November 1987.
                                                                                                                                                76
-------
   20   Espostto,  P.,  et  al.  Results of Treatment Evaluations of Contaminated
        Soils.   EPA Contract  No. 68-03-3413.  U.S. Environmental Protection
        Agency,  Risk Reduction  Engineering Laboratory, Cincinnati, Ohio.  1987.

   21.   Esposlto,  P.,  et  al.  Superfund Standard Analytical Reference Matrix
        Preparation and Results of Physical Soils Washing Experiments.  EPA
        Contract Ho. 68-03-3413, U.S. Environmental Protection Agency, Risk
        Reduction  Engineering Laboratory, Cincinnati, Ohio.   1987.
-Cr
oo
                                           77
                                                                                                                                             APPENDIX A
                                 PROGRAM AGENDA

               WORKSHOP OH EXTRACTIVE TREATMENT OF EXCAVATED SOIL
                               DECEMBER 1-2, 1988
                      AT:  USEPA, TIX - CONFERENCE CENTER
                        RARITAN DEPOT, WOOOBRIOGE AVENUE
                         EDISON, NEW JERSEY  08837-3679

                                    Sponsor

                   U.S. Environmental Protection Agency (EPA)
                         Releases Control Branch (RC8)
                  Superfund Technology Demonstration Division
                  Risk Reduction Engineering Laboratory (RREL)
                                                                                                                                               AGENDA
December 1. 1988 - Thursday

8:15-8:40      Registration

8:40-9:00      Welcome and Introductory remarks
               F. Freestone (EPA/RCB)

9:00-9:20      "State-of-the-Art of Soil Washing Technology*
               R. Raghavan (Foster Wheeler Envlresponse, Inc.)

9:20-9:40      "Assessment of International Technologies for Superfund
               Applications*
               T. Phetffer (EPA/Offtee of Solid Waste and Emergency Response)

9:40-10:00     Break
                                                                                                          10:00-10:20


                                                                                                          10:20-10:40


                                                                                                          10:40-11:00


                                                                                                          11:00-11:40
               Technical Session - Site Characterization

               Moderator:  M. Stlnson (EPA/RCB)

               "Koc, The Unconstant Constant*
               W. tyman (Camp Dresser McKet. Inc.)

               'Case Histories for Underground Storage Tanks*
               R. Griffiths (EPA/RCB)

               •Characterization of RCRA/CERCLA Sites with Contaminated Soil*
               P. Esposlto (Bruck, Hartman, and Esposlto, Inc.)

               Question-Answer Period - Discussion
                                                                                                                                                  78
-------
  11:40-1:00
                 Lunch
                 Technical Session - Techniques/Experiences  for Metals  Extraction
                 Moderator:  R. Traver (EPA/RCB)
   1:00-1:20      'Hydrometallurglcal Treatment of Soil'
                 W. Schmidt (U.S. Bureau of Mines)
   1:20-1:40      'Lead Extraction From Excavated  Soil*
                 A. Zownlr (EPA - Emergency Response Team)
   1:40-2:00      'Innovative Electromembrane Process for Recovery of Lead From
                 Contaminated Soils'
                 E. Krlshnan (PEI Associates, Inc.)
   2:00-2:40      Question-Answer Period - Discussion
   2:40-3:00      Break
-Cr
(JO
OO
               Technical  Session  - Techniques/Experiences
               For Radioactive Materials Extraction
               Moderator:   Oarlene UtIKams  (EPA/RCB)
3:00-3:20      'Soil  Washing and  Chemical  Extraction of RadlonuclIdes'
               U.  Richardson (EPA -  Office of  Radiation Programs)
3:20-3:40      'Radium (226) Removal From  a  Contaminated Soil'
               K.  Haque (Canadian Center for Mineral and Energy  Technology)
3:40-4:00      'Remediation of Formerly Utilized Sites Remedial  Action  Project
               (FUSRAP) Sites'
               R.  Atkln (U.S. Department of  Energy)
4:00-4:40      Question-Answer Period - Discussion
   December 2. 1988 - Friday - Technical  Session (continued)
    8:00-8:20
               Technical Session - Techniques/Experiences
               For Qraanlcs Extraction
               Moderator:  J. Brugger (EPA/RCB)
               "Btotrol Soil Washing Systems for Removal of Organic
               Contamination at Wood Treating Sites"
               S. Vallne (Blotrol, Inc.)
                                           79
                                                                                                       8:20-8:40

                                                                                                       8:40-9:00

                                                                                                       9:00-9:20

                                                                                                       9:20-9:40
                                                                                                       9:40-10:00

                                                                                                       10:00-10:20

                                                                                                       10:20-11:00
                                                                                                       11:00-11:20
                                                                                                       11:20-1:00
                                                                                                       1:00
                                                                                                       1:00-2:00
 "Experience Gained With a Soil-Decontamination System In Berlin*
 M.  Nells (Harbauer, GmbH t Co. AG, Berlin, W. Germany)
                                                    !
 "OrganIcs Removal  by Froth Flotation as a Soil Washing Process"
 P.  Trost (KTA Remedial  Resources, Inc.)
 "The B.E.S.T.™ Solvent Extraction Process for Removing
 Hydrocarbons From  Soil  and Sediments*
 D.  Austin (Resource Conservation Co.)
 Break
 "Surfactants for Washing of Petroleum From Soil"
 A.  Abdul  (General  Motors Research Laboratory)
 "EPA Soil  Washing  Technology Overview - Good Economic Sense*
 R.  Traver (EPA/RCB)
 Question-Answer Period  - Discussion
 Break
 Summary  and Roundtable  Discussion
 Moderator:   F.  Freestone (EPA/RCB)
 o   Statement of problems/problem types
 o   RepetHlveness  of problem types
 o   Types  of data/measurements needed  to characterize  problems
 o   Tractability of problems
    -  which are 'simple"
    -  which are "complex"
 o   Need  for future,  more detailed discussions of soil
    wash1ng/extract1on
 End of workshop
 Tour of EPA wblle  soil  washing  systems, R. Traver (EPA/RCB):
o  Full-scale soil  washer
o  Mini soil washer
                                                                                                                                                 80
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     NAME


 1.   ABDUL, A.


 2.   ATKIN, R.


 3.   AUSTIN,  DOUG


 4.   BASILICO,  JIM


 5.   BONACCI, JOHN


 6.   BRUGGER, J.


 7.   CANZIUS, PRESTON


 8.   COCHRAN, STEVE


 9.   COLES.  E.


10.   DYER.  ROBERT


11.   EBERLY,  DAVID


12.   ELLIS, W.D.


13.   ESPOSITO.  P.


14.   EVANGELISTA, PATRICK
   APPENDIX B

LIST OF ATTENDEES


ORGANIZATION/PHONE I
GENERAL MOTORS RESEARCH LABORATORY
(313) 986-1600

U.S. DEPARTMENT OF ENERGY
 FTS  626-1826

RCC
(206) 828-2400

EPA/WASHINGTON ORD
      382-2583

SAIC
(201) S99-0100

EPA/RCB
(201) 321-6634

EPA REGION 2
(212) 264-6315

OFFICE OF SOLID HASTE
(202) 475-9715

ENVIRESPONSE, INC.
(201) 906-9844

EPA-UASHINGTON
(202) 475-9630

EPA HEADQUARTERS
(202) 382-4691

SAIC
(703) 734-2529

BRUCK, HARTMAN, & ESPOSITO,  INC.
(513) 563-0010

EPA REGION 2
(212) 264-6311
                                  81
                                                                                                                                LIST OF ATTENDEES
      NAME


 15.  EVANGELISTA, ROBERT


 16.  FAN, EVAN


 17.  FARLOW, JACK


 18.  FELDSTEIN, JANET


 19.  FREESTONE, F.


 20.  FUCHS,  JOHANNES


 21.  FUHRMANN,  MARK


 22.   GLYNN,  WILLIAM


 23.   GOODMAN,  IRIS


 24.   GOTLIEB,  ITZHAK


 25.   GRIFFITHS, R.


 26.  GRUNFELD, HIKE


 27.  GUTTERMAN, C.


28.  HAQUE,  K.
 ORGANIZATION/PHONE  I


 WESTON/REAC
 (201) 906-3488

 EPA RCB
 (201) 906-6924

 EPA
 (201) 321-6635/ FTS 340-6635

 EPA REGION 2
 (212) 264-0613

 EPA/RCB
 (201) 321-6632/ FTS 340-6632

 EPA
 (201) 548-6030

 BROOKHAVEN NATIONAL LAB.
 (516) 282-2224

 COM
 (201)  325-1337

 OUST  (OFFICE  OF  UST)
 (202)  382-4758

 GHEA  ASSOCIATES
 (201)  226-4642

 EPVRCB
 (201)  321-6629

 EPA
 (201) 321-6625

 ENVIRESPONSE,  INC.
 (201) 906-6866

CANADIAN CENTER FOR MIN. &  ENER.  TECH.
 (613) 992-2172
                                                                                                                                     82
-------
                                  LIST OF ATTENDEES
-Cr
-t
O
      NAME


 29.   INSALACO,  SAM


 30.   KALCEVIC,  VICTOR


 31.   KAUP,  EDGAR


 32.   KELLY.  MEG


 33.   KOLLITIDES, ERNEST


 34.   KRISHNAN,  R.


 35.   LAFORNARA, JOSEPH


 36.   LAND,  ROGER


 37.   LEONARD, PAUL


 38.   LIBR1ZZI , WILLIAM


 39.   LISKOWITZ, JOHN


 40.   LYNAN, W.


. 41.   MARTIN, J.P.


 42.   MARTIN, JOHN
                                  ORGANIZATION/PHONE I
OH MATERIALS
(419) 423-3526

IT CORPORATION
(615) 690-3211

NJDEP
(609) 633-0701

OSWER
(202) 382-7953

OEHYDROTECH CORP.
(201) 887-2182

PEI ASSOCIATES, INC.
(513) 782-4700

ERT
(201) 321-6741

BECHTEL NATIONAL INC.
(615) 576-3S24/ FTS 626-3824

EPA REGION 3
(215) 597-8257

NO IT
(201) 596-2457

NJIT
(201) 596-3234

CAMP DRESSER MCKEE,  INC.
(617) 742-5151

OREXEL UNIVERSITY
(215) 895-2363

EPA  - CINCINATTI
(513) 569-7758
                                         83
                                                                                                                                     LIST OF ATTENDEES
     NAME


43.  MASTERS, HUGH


44.  MCGOVERN, BILL


45.  MCKNIGHT, ROBERT


46.  MCNEVIN, TOM


47.  MICHALOWICZ, JOHN


48.  NASH, JIM


49.  NEILS,  M.


50.  NUNNO,  THOMAS  J.


51.  PHEIFFER,  T.


52.  RAGHAVAN,  R.


53.  RENDER, TIM


54.  RICHARDSON, WILLIAM


55.  ROBINSON.  TERRY


56.  ROUBO,  A.
                                                                                                                                     ORGANIZATION/PHONE I
EPA/RCB
(201) 321-6678/ FTS 340-6678

CF SYSTEMS
(617) 890-1200

EPA REGION 2
(212) 264-7509

NJDEP
(609) 984-9766

EPA
(201) 548-6030

R.F. WESTON
(201) 906-3464

HARBAUER, GMBH  &  CO.  AG,  W.  GERMANY
(202) 554-8682

ALLIANCE TECH.  CORP.
(617) 275-9000

EPA  OFFICE OF SOLID WASTE & EMERG. RESP.
  FTS 382-4477

ENVIRESPONSE, INC.
  FTS 340-6821

EPA  REGION 8
 (303) 293-1530/ FTS 564-1530

EPA  EERF
 (205) 272-3402

DREXEL  UNIVERSITY
 (215) 895-1633

 ENVIRESPONSE. INC.
 (201)  530-6144
                                                                                                                                             84
-------
                            LIST OF ATTENDEES
     NAME


57.  SCHMIDT, H.


58.  SKRIBA, MICHAEL


59.  SNOOGRASS. GARY


60.  STINSON. H.


61.  TAFURI. TONY


62.  TRAVER, R.


63.  TROST, P.


64.  VALINE. S.


65.  WEIT7MAN. LEO


66.  WILHELM. RON


67.  MILKENS, KALVINA


68.  WILLIAMS, DARLENE


69.  WOOD, JOSEPH


70.  ZOUNIR, A.
ORGANIZATION/PHONE I
U.S. BUREAU OF MINES
(202) 634-1210

UESTINGHOUSE R ft 0
(412) 256-2111

OFFICE OF RADIATION PROGRAMS
(202) 475-9630

EPVRCB
(201) 321-6683

EPA
 FTS  340-6604

EPVRCB
(201) 321-6677

NTA REMEDIAL RESOURCES. INC.
(303) 279-4255

BIOTROL, INC.
(612) 448-2515

ACUREX CORP.
(919) 544-4535

OSWER
 FTS  382-7944

EPA
(201) 906-6896

EPVRCB
(201) 906-6925/ FTS 340-6925

EERF
(205) 272-3402

EPA  - ENVIRONMENTAL RESPONSE TEAM
(201) 321-6744
                                  85
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442
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            Presented at the Seventeenth Annual Hazardous Waste
            Research Symposium, Cincinnati, OH  April 9-11, 1991
             EPA's MOBILE VOLUME REDUCTION UNIT FOR SOIL WASHING
                  by:   Hugh  Masters
                       Releases  Control Branch
                       Risk  Reduction  Engineering  Laboratory
                       US  Environmental Protection Agency
                       Edison, New Jersey  08837

                       Bernard Rubin
                       Roger Gaire
                       Porfirio  Cardenas
                       Foster Wheeler  Enviresponse,  Inc.
                       Livingston, New Jersey   07039
                                   ABSTRACT

      This paper discusses the design  and  initial  operation of the U.S.
Environmental  Protection Agency's (EPA)  Mobile Volume Reduction Unit (VRU) for
soil  washing.   Soil  washing removes contaminants from soils by dissolving or
suspending them in the wash solutions  (which can be later treated by conven-
tional wastewater treatment methods) or  by volume reduction through simple
particle size  separation techniques.  Contaminants are primarily concentrated
in the fine-grained (<0.063 mm, 0.0025") soil  fraction.  The VRU is a pilot-
scale mobile system for washing soil contaminated with a wide variety of heavy
metal and organic contaminants.  The unit  includes state-of-the-art washing
equipment for  field applications.

      The VRU  equipment was originally conceived by the EPA.  It was designed
and fabricated by Foster Wheeler Enviresponse, Inc. under contract to EPA's
Risk Reduction Engineering Laboratory  (RREL) in Edison, New Jersey, with the
following objectives:

1.    To make  available to members of  the research community and to the
      commercial sector the results of government research on a flexible,
      multi-step, mobile, pilot-scale  soil washer capable of running treatabi-
      lity studies on a wide variety of  soils;

2.    To demonstrate the capabilities  of soil  washing; and

3.    To provide data that facilitate  scaleup to commercial size equipment.

      The design capacity of the VRU is  100 Ib/hr of soil, dry-basis.  The VRU
consists of process washing equipment  and utility support services mounted on
two heavy-duty semi-trailers. The process trailer equipment accomplishes
                                 443
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material handling, organic vapor recovery,  soil  washing, coarse soil screen-
ing, fine particle separation, flocculation/clarification, and steam genera-
tion via a boiler.  The utility trailer carries  a power generator, a process
water cleanup system, and an air compressor.   The VRU is controlled and
monitored by conventional industrial process  instrumentation and hardware.

      Shakedown operations are currently in progress and future plans include
testing EPA-produced synthetic soil matrix (SSM) spiked with specific chemical
pollutants.  The addition of novel, physical/chemical treatment processes,
such as sonic/ultrasonic cleaning and acid leaching, will expand the VRU's
extraction capability in soil decontamination.
                                  444
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INTRODUCTION

      Section 121(b) of the Comprehensive Environmental Response, Compensa-
tion, and Liability Act (CERCLA) mandates the EPA to select remedies that
"utilize permanent solutions and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable" and to
prefer remedial actions in which treatment "permanently and significantly
reduces the volume, toxicity, or mobility of hazardous substances, pollutants,
and contaminants as a principal element."

      In most cases soil washing technologies are used in conjunction with
other remedial methods for the separation/segregation and volume reduction of
hazardous materials in soils, sludges, and sediments.  In some cases, however,
the process can deliver the performance needed to reduce contaminant con-
centrations to acceptable levels and, thus, serve as a stand-alone technology.
In treatment combinations, soil washing can be a cost-effective step in
reducing the quantity of contaminated material to be processed by another
technology, such as thermal, biological, or physical/chemical treatment.   In
general, soil washing is more effective on coarse sand and gravel; it is less
successful  in cleaning silts and clays.

      A wide variety of chemical contaminants can be removed and/or con-
centrated through  soil washing applications.  Removal efficiencies depend  on
both  the soil characteristics  (e.g.,  soil geology and particle size) and the
processing  steps contained within the soil washer.  Experience has shown that
volatile organics  can be removed with 90+% efficiency.  Semivolatile organics
are  removed to a lesser extent  (40-90 percent).  They usually require the
addition of surfactants to the wash water.  Surfactants are surface-active or
wetting  agents, that reduce  the surface tension at the interface between the
hydrophobic contaminants and the soil, thereby promoting release of the
contaminants  into  the aqueous  extraction medium.

      Metals which are  less  soluble  in water, often require acids or chelating
agents  for  successful soil washing.   A chelating agent, such as ethylenedi-
aminetetraacetic acid  (EDTA),  bonds with the metal and facilitates
                                   445
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solubilization in the extraction medium.

      The VRU process can be applied to the treatment of soils contaminated
with hazardous wastes such as wood-preserving chemicals (pentachlorophenol,
creosote), electroplating residues (cyanides, heavy metals), organic chemical
production residues, and petroleum/oil residues.  The applicability of soil
washing to general contaminant groups and soil types is shown in Table 1.
This table has been reproduced from an EPA report, "Treatment Technology
Bulletin - Soil Washing," dated May 1990.

      The EPA has developed the VRU to meet the following objectives:

1.    To make available to members of the research community and to the
      commercial sector the results of government research on a flexible,
      multi-step, mobile, pilot-scale soil washer capable of running treatabi-
      lity studies on a wide variety of soils;

2.    To demonstrate the capabilities of soil washing; and

3.    To provide data that facilitates scaleup to commercial size equipment.

      The EPA plans to investigate other extraction processes which may be
added to the VRU at a later data.  The addition to the VRU of novel physi-
cal/chemical treatment processes, such as sonic/ultrasonic cleaning and acid
leaching, will expand its overall extraction  capability in soil decontamina-
tion.

SYSTEM  DESCRIPTION

      The VRU is a mobile, pilot-scale washing system for stand-alone field
use  in  cleaning  soil contaminated with hazardous  substances.  The VRU is
designed to decontaminate certain soil fractions  using state-of-the-art
washing equipment.  The total  system consists of  process equipment and support
utility systems  mounted on two heavy-duty, semi-trailers.
                                    446
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                    Table 1
Applicability of Soil Washing on General Contaminant
             Groups for Various Soils

Contaminant Croups



.0
o
O




Inorgank

Reactive
T
Q
Haiogenated voiatiles
Haiogenated semivoiatiles
Nonhalogenated voiatiles
Nonhalogenated semivoiatiles
PCBs
Pesticides (haiogenated)
Dioxins/Furans
Organic cyanides
Organic corrosives
Volatile metals
Nonvolatile metals
Asbestos
Radioactive materials
Inorganic corrosives
Inorganic cyanides
Oxidizers
Reducers
Good to Excetioit AoDfcabtiitv Htahr
successful
Moderate to Marginal Appticabilfty: Ex
Not Applicable Expert opinion that to
Matrix
Sandy/ SOty/Clay
Gravely So/if Softs
•
T
•
T
T
T
T
T
T
•
Q
T
T
T
T
V
T
T
T
T
T
T
T
T
T
T
T
a
T
T
T
T.
T
wobabiKty that technology wtil be
o«se v*« HI cnoosing lecnnoioojy
chnoiogy w»« not wont
                     447
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      Figure 1,  General  Block Diagram,  shows the VRU basic pilot plant
subsystems as follows:

1.    Soil handling and  conveying
2.    Organic vapor recovery
3.    Soil washing and  coarse screening
4.    Fines/fleatables  gravity separation
5.    Fines flocculation/water clarification and solids disposal
6.    Water treatment
7.    Utilities - electric generator,  steam boiler, and compressed air unit

      The generator, air compressor,  water heater, water filters/carbon
adsorbers, recycle water pump, gasoline tank (for the generator) and delisting
tank are located on the utility trailer.  All remaining equipment is located
on the process trailer.   The VRU system is controlled and monitored by conven-
tional industrial process instrumentation and hardware, including safety
interlocks, alarms, and shutdown features.

PROCESS DESCRIPTION

      Figures 2, 3, and 4 present the Process Flow Diagram for all VRU
subsystems in terms of their process  equipment functions.

1.    Soil Handling and Conveying

      Raw soil is delivered from battery limits to a vibrating grizzly that
      separates the particles greater than +i" into a drum for redeposit and
      collects the smaller particles  (-i" +0) for transfer to the feed surge
      bin.  (One half-inch is the maximum particle size that can be handled in
      the mini-washer,  but smaller screen sizes may be selected.)  From this
      bin, the -}" soil  is conveyed through a steam-jacketed screw conveyor
      where the volatile organics and water are vaporized.  Both live steam
      and jacketed steam can be introduced so that the efficiency of the steam
      extraction can be determined.  The conveyor flow is adjusted by a speed
                                  448
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             Raw
         contaminated
             soil
VO
                                -2-
                           Organlc vapor
                             recovery
                                                     Fines
                                            To posttreatment
     -1-
Soll handling
     and
  conveying
      -3-
  Soll washing
      and
coarse screening
            Make up/
            recycle
            water
                                                                                Floatables   To posttreatment
                                                                              1
       -4-
 Fines/fleatables
gravity separation
                                                               -1/2" +10-mesh  (0.079"/2mm)  solids
                                                   To redeposit or
                                                   further treatment
                                                   -10 +60 mesh  (-0.079"[2mm] + 0.0098"[0.25 mm])
                                                   To redeposit or
                                                   further treatment
                               -5-
                        Flnes  flocculatlon/
                        water  clarification
                        and solids disposal
                                                                                 Makeup water
                                                                     To  dellstlng/dlsposal
                                                       Slowdown       or  posttreatment  	
                                                                                 Clay/silt sludge  To posttreatment.
                               -7-
                        Utllltles
                        -  Electric generator
                        -  Boiler
                        -  Compressed air
                         Figure 1.   General  Block  Diagram - The U.S. Environmental  Protection Agency
                                        Volume Reduction Unit (VRU) for Soil  Washing
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-------
controller on the conveyor motor.  The solids pass through a motor-operated
rotary valve (which prevents air infiltration), then into the feed hopper of
the mini-washer.

2.    Organic Vapors Recovery

      Volatiles stripped from the soil in the screw conveyor are either
      collected in the volatile organic compounds (VOC) condenser and fall by
      gravity into the process condensate seal tank, or are adsorbed in
      vapor-phase activated carbon containers located upstream of the vent
      blower.

      The spent carbon will be periodically replaced based on vent gas
      analyses.  The vapor train is maintained under vacuum by an induced
      draft blower.  The vacuum level  is adjusted by manual admittance of
      atmospheric air upstream of the  blower to maintain a slight negative
      pressure  on the vapor system.  Clean vapors, leaving the blower, vent to
      the atmosphere.

3.    Soil Washing and Coarse Screening

      Soil is fed to the mini-washer at a controlled rate of approximately 100
      Ib/hr by  the screw feeder.  Filtered wash water, which can be heated to
      150'F  (maximum), is  added to soil in the feed hopper and also sprayed
      onto an internal slotted trommel screen  (with a  10-mesh  (0.079") slot
      opening)  mini-washer.  Five manually controlled meters can control the
      flow up to  approximately 10:1 overall weight ratio water to soil.  Hot
      water  should be more efficient  in extracting contaminants, but heating
      is  optional.  When required, dilute surfactant/detergent, and/or caustic
      can be metered at a  controlled  rate into the feed hopper.

      Two vibrating  screens, equipped  with anti-blinding devices, are provided
      to  continuously segregate  soil  into various size fractions.  These
      screened  fractions can be  collected to measure the effectiveness of con-
      taminant  removal for each  soil  fraction  recovered, and to determine the
                                    453
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      effectiveness  of soil  washing in cleaning a particular contaminated soil
      fraction  to achieve sufficient volume reduction.

      Mini-washer overflow,  containing the coarser solids,  falls onto the
      first 10-mesh  (0.079"/2 mm)  vibrascreen.   First vibrascreen overflow
      (-J"  + 10 mesh (0.079"/2 mm)) solids flow by gravity  down to a recovery
      drum.  The underflow is pumped at a controlled rate,  using a progressing
      cavity pump, onto the  second 60-mesh (0.0098"/0.25 mm) vibrascreen where
      it is joined by the Mini-Washer underflow.

      The overflow from the  second vibrascreen  (- 10-mesh (0.079") + 60-mesh
      (0.0098")), is gravity fed to another recovery drum.   Second vibrascreen
      underflow (a fines slurry) drains into an agitated tank.   The VRU is
      designed  with the following flexibility:

      a.    The mesh sizes for both the mini-washer and vibrascreens can be
            varied (i.e., the screen size could be 20- or 30-mesh (0.033" or
            0.023").

      b.    Additional soil  cleaning by use of  water sprays or steam sprays
            will be evaluated for each vibrascreen.

      c.    Screened soil fractions, collected  in the recovery drums, can be
            redeposited if sufficiently cleaned or further cleaned by addition
            of rinse water,  followed by reslurrying and pumping the slurry
            back over the screens  (recycle mode).  In the future these soil
            fractions will be sent for treatment by various extraction units
            currently under development by EPA's RREL in Edison, New Jersey.

4.    Fines/Floatables Gravity Separation

      Slurry from the second screen (fines slurry) tank, containing particles
      less than 60-mesh (0.0098"/0.25 mm) in size, is pumped to a Corrugated
      Plate Interceptor (CPI).  Material lighter than water (floatables such
      as oil) will overflow an internal weir, collect in a  compartment within
                                   454
-------
      the CPI,  and drain  by  gravity to a drum for disposal.   CPI-settled
      solids (soil particles -  60-  to about 400-mesh  (0.0098" to about
      0.0015")  will  be  discharged  by the bottom auger to a  recovery drum.
      The VRU has the flexibility to redeposit or further clean these settled
      soils, if required,  by addition of rinse water  followed by pumping the
      slurry back through the CPI.   As mentioned above,  these soils could also
      be sent,  in the future, to an extraction unit.

5.    Fines Flocculation.  Water Clarification, and Solids Disposal

      Aqueous slurry, containing fines less than about 400-mesh (34 urn/
      0.0014"), overflow  the CPI and gravity feed into an agitated tank.  The
      slurry is then pumped  to a static flash mixer located  upstream of the
      floe clarifier's mix tank.  Flocculating chemicals are introduced into
      this static flash mixer.   Typically, liquid alum and aqueous polyelec-
      trolyte solutions are  metered into the static flash mixer to neutralize
      the repulsive electrostatic charges on colloidal particles (clay/humus)
      and promote coagulation.   The fines slurry is discharged into the floe
      chamber which has a varispeed agitator for controlled  floe growth (sweep
      flocculation).  Sweep flocculation refers to the adsorption of fine
      particles onto the floe (colloid capture) and continuing floe growth to
      promote rapid settling of the floe and its removal from the aqueous
      phase.  The floe slurry overflows into the clarifier (another corrugated
      plate unit).  Bottom solids are gravity fed by an auger to a drum for
      disposal, or to the sludge slurry tank  (depending on solids concentra-
      tion) for subsequent concentration in a filter package unit.  Con-
      centrated cake from the filter  is discharged to another drum for
      disposal.   This system has the  ability to clarify the process water and
      dewater the sludge.  The efficiency of solids dewatering can be deter-
      mined, and  cost savings estimated, for trucking waste sludge to a dis-
      posal/treatment site.

6.    Water Treatment

      Clarified water is polished with  the objective of reducing suspended
                                   455
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      solids  and  organics  to  low  levels  that  permit  recycle of spent wash-
      water.  Water  is  pumped from  the floe settler  overflow tank at a
      controlled  rate through cartridge-type  polishing  filters operating in
      parallel,  in order to remove  soil  fines greater than  10-um (3.94xlO~4").
      One  urn  (3.9xlO~5") cartridges are available, if required.

      Water leaving  the cartridge filter flows through  activated carbon drums
      for  removal of hydrocarbons.   The  carbon drums may  be operated either in
      series  or  parallel,  and hydrocarbon breakthrough  monitored by sampling.
      A drum  will be replaced when  breakthrough has  been  detected.

      In order to recycle  water and maintain  suitable dissolved solids and
      organic levels, aqueous bleed (blowdown) to the boiler delisting tank
      may  be  initiated  at  a controlled rate.   Delisted  material will be sealed
      in drums and sent for disposal  in  accordance with respective state and
      local regulations.

      Treated recycle  (recovered) water  is sampled for  analysis before it
      flows  into the process  water storage tank.   Supplementary water is fed
      into this  tank from  a tank  truck.   Recovered and  added water is pumped
      by the  water recycle pump (and optionally fed  to  the  water heater) for
      subsequent feed to the  mini-washer.  A  side stream  from the water
      recycle pump is utilized as cooling water in the  VOC  condenser and
      either  returned to the  process water storage tank or  sent to the
      sewerage system.

7.    Utilities  Systems

      The  VRU is equipped  with a  steam boiler, electric generator,  and a
      compressed air system.

Field Operations

      While  in the field,  the VRU would  be supported by a decontamination
trailer, a mobile treatability lab/office, and a storage  trailer for supplies,
                                   456
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spare parts, miscellaneous tools, etc.

Summary of VRU Features

1.    The VRU is a mobile, pilot-scale washing system for field use in
      cleaning soil contaminated with hazardous materials, using state-of-the-
      art washing equipment and support utilities.

2.    The unit has the ability to remove VOCs by steam heating and stripping.

3.    It is capable of washing with water  (in combination with surfac-
      tants/detergents) up to a 10:1 water to soil ratio while also varying
      water temperature from ambient to 150°F.

4.    The mini-washer screen and vibrascreens can be varied in mesh size.
      Additional use of soil cleaning by water or steam sprays on the vibra-
      screen decks can be evaluated.

5.    Three screened soil fractions (including CPI-settled solids) can be
      further cleaned by  slurrying with the addition of rinse water and
      recycling the slurry over the vibrascreens or the CPI.

6.    The floc-clarifier  system has the ability to clarify the process water
      and dewater  the sludge.

7.    Additional treatment of the clarified process water through polishing
      filters and  activated carbon should  allow, in most cases, reuse of this
      water for recycle to the washing circuit.

8.    Side  streams from the VRU will  be treated using various physical/chem-
      ical  extraction units currently under development by EPA.

9.    The VRU offers a unique method  for conducting treatability studies on
      various contaminated soils.
                                    457
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REFERENCES

1.    Foster Wheeler Enviresponse, Inc., "Cleaning Excavated Soil Using
      Extraction Agents:  A State-of-the-Art Review," January, 1990, EPA/600/
      S2-89/034.

2.    Foster Wheeler Enviresponse, Inc., "Workshop of Extractive Treatment of
      Excavated Soil," December, 1988.

3.    EPA Treatment Technology Bulletin, "Soil Washing," Draft issued May,
      1990.

4.    Traver, R.P., "Development and Use of the EPA's Synthetic Soil Matrix
      (SSM/SARM)."  U.S. EPA Releases Control Branch, Risk Reduction Engineer-
      ing Laboratory, Edison, N.J., 1989.
                                    458
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&EPA
                           United States
                           Environments! Protection
                           Agency
                           Office of Emergency and
                           Remedial Response   .
                           Washington, DC 20460
Office of
Research and Development
Cincinnati, OH 45268
                           Superfund
                           EPA/540/2-9Q/013
September 1990
Engineering Bulletin
Solvent  Extraction Treatment
                                                                         '•ft'.'''
Purpose

    Section 121(b) of the  Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) mandates
the Environmental Protection Agency (EPA) to select remedies
that "utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum
extent practicable" and to prefer remedial actions in which
treatment "permanently and significantly reduces the volume,
toxicity, or mobility of hazardous substances, pollutants and
contaminants as a principal element" The Engineering Bulletins
are a series of documents that summarize the latest information
available on selected treatment and  site remediation
technologies and related issues. They provide summaries of
and references for the latest information to help remedial
project managers,  on-scene coordinators, contractors, and
other site cleanup managers understand the type of data and
site characteristics needed to evaluate a technology for potential
applicability to their Superfund or other hazardous waste site.
Those documents that  describe individual treatment
technologies focus  on  remedial investigation scoping needs.
Addenda will be issued periodically to update the  original
bulletins.
Abstract

    Solvent extraction does not destroy wastes, but is a means
of separating hazardous contaminants from soils, sludges, and
sediments, thereby reducing the volume of the hazardous
waste that must be treated. Generally it is used as one in a series
of unit operations, and can reduce the overall costfor managing
a particular site.  It  is applicable to  organic wastes and is
generally not used for treating inorganics and metals  [15,
p.64].* The technology uses an organic chemical as a solvent
[14, p. 30], and differs from soil washing, which generally uses
water or water with wash improving additives. During 1989,
the technology was one of the selected remedies at six Superfund
sites. Commercial-scale units are in operation. There is no clear
solvent extraction technology leader by virtue of the solvent
employed, type of equipment used, or mode of operation. The
final determination of the lowest cost alternative will be more
site specific than process equipment dominated. Vendors should
be contacted to determine the availability of  a unit for a
particular site.  This bulletin provides information on the
technology applicability, the types of residuals produced, the

* [reference number, page number]
                               latest performance data, site requirements, the status of the
                               technology, and sources for further information.
                              Technology Applicability

                                  Solvent extraction has been shown to be effective in
                              treating sediments, sludges, and soils containing primarily
                              organic contaminants such as polychlorinatedbiphenyls(PCB),
                              volatile organic compounds (VOQ, halogenated solvents, and
                              petroleum wastes.  The technology is generally not used for
                              extracting inorganics (i.e., acids, bases, salts, heavy metals).
                              Inorganics usually do  not have a detrimental effect on the
                              extraction of the organic components, and sometimes metals
                              that pass through the process experience a beneficial effect by
                              changing the chemical compound to a less toxic or teachable
                              form. The process has been shown to be applicable for the
                              separation of the organic contaminants in paint wastes, synthetic
                              rubber process wastes, coal tar wastes, drilling muds, wood
                              treating wastes, separation sludges, pesticide/insecticide wastes,
                              and petroleum refinery oily wastes [3].

                                  Table 1 lists the codes for the specific Resource Conservation
                              and Recovery Act (RCRA) wastes that have been treated by this
                              technology [3][1, p.11 ]. The effectiveness of solvent extraction
                              on general contaminant groups for various matrices is shown
                              in Table 2 [13, p.1 ] [ 15, p.10]. Examples of constituents within
                              contaminant groups are provided in Reference 15, "Technology
                              Screening Guide for Treatment of CERCLA Soils and Sludges."
                              This table is based on the current available information or
                              professional judgment where no information was available.
                              The proven effectiveness of the technology for a particular site
                              or waste does not ensure that it will be effective at all sites or that
                              the treatment efficiencies achieved will be acceptable at other
                              sites.  For the  ratings used for this table,  demonstrated
                              effectiveness means that, at some scale treatability was tested
                              to show the  technology was effective for that  particular
                              contaminant and matrix. The ratings of potential effectiveness,
                              or no expected effectiveness are  both  based upon  expert
                              judgment  Where potential  effectiveness  is  indicated, the
                              technology is believed capable of successfully treating the
                              contaminant group in a particular matrix. When the technology
                              is not applicable or will probably  not work for a particular
                              combination of contaminant group and matrix, a no-expected-
                              effectiveness rating is given.
                                                 459
                                                            Printed on Recycled Paper
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Limitations

    Organically bound metals can co-extract with the target
organic pollutants and become a constituent of the concentrated
organic waste stream.   This  is an unfavorable  occurrence
because the presence of metals can restrict both disposal and
recycle options.
                       Table 1
            RCRA Codes for Wastes Treated
                 by Solvent Extraction
     Wood Treating Wastes                    K001
     Water Treatment Sludges                  K044
     Dissolved Air Flotation (DAF) Float           K048
     Slop OH Emulsion Solids                   K049
     Heat Exchanger Bundles Cleaning Sludge     KOSO
     American Petroleum Institute (API)
        Separator Sludge                      K051
     Tank Bottoms (leaded)                    K052
     Ammonia Still Sludge                     K060
     Pharmaceutical Sludge                    K084
     Decanter Tar Sludge                      K089
     Distillation Residues                      K101
                       Table 2
         Effectiveness of Solvent Extraction on
           General Contaminant Groups for
              SoU. Sludge, and Sediments

Treatability Croups















i
•
V
Q
Halogenated volatile
Hatogenated semivolatiles
Nonhalogenated volatile
Nonhalogenated semivolatiles
PCBs
Pesticides
Dioxins/Furaro
Organic cyanides
Organic corrosives
Volatile metals
Nonvolatile metals
Asbestos
Radioactive materials
Inorganic corrosives
Inorganic cyanides
Oxidizers
Demonstrated Effectiveness: Successfu
wme scale completed
No Expected Effectiveness: Expert opfn

Effectiveness
Soil Sludqe Sediments






T
V
T
Q
Q
Q
Q
Q
Q
Q
T






V
T
Q
Q
0
Q
Q
Q
Q







T
T
Q
Q
Q
Q
Q
Q
Q
1 testability tot »t
that technology will work
on that technology win not work
    The presence of detergents and emulsffiers can unfavorably
influence extraction performance and materials throughput
Water-soluble detergents, found in some raw wastes (particularly
municipal), will dissolve  and  retain organic pollutants in
competition with the extraction solvent.  This can impede a
system's ability to achieve low concentration treatment levels.
Detergents and emulsifiers can promote the evolution of foam,
which  hinders separation and settling characteristics and
generally decreases materials throughput. Although methods
exist to combat these problems, they will add to the process
cost

    When treated solids leave the extraction subsystem, traces
of extraction solvent will be present [8, p. 125]. The typical
extraction solvents  used in currently  available systems either
volatilize quickly from the treated solids or biodegrade easily.
Ambient air monitoring can be employed to determine if the
volatilizing solvents present a problem.

    The types of organic  pollutants that can be extracted
successfully depends, in part, on the nature of the extraction
solvent Invariably, treatability tests should be conducted to
determine which solvent or combination of solvents  is best
suited to the site-specific vagaries of  a particular parameter/
matrix mix. In general, solvent extraction is least effective on
very high molecular weight organics and very hydrophilic
substances.

    Some commercially available extraction systems use
solvents that are either flammable or mildly toxic or both [20,
p. 2]. However, there are long-standing standard procedures
used by chemical companies, gasoline stations, etc, that can
be used to greatly reduce the potential for accidents.
                                                             Technology Description

                                                                 Figure 1 is a general schematic of the solvent extraction
                                                             process[3]ns,p.65][4,p.3].

                                                                 Waste preparation (1) includes excavation and/or moving
                                                             the waste material to the process where it is normally screened
                                                             to remove debris and large objects. Depending  upon the
                                                             process  vendor and whether the process is semibatch or
                                                             continuous, the waste may need to be made pumpable by the
                                                             addition of solvent or water.

                                                                 In the extractor (2), the waste and solvent mix, resulting in
                                                             the organic contaminant dissolving into the solvent   The
                                                             extraction behavior exhibited by this technology is typical of a
                                                             mass  transfer controlled  process, although equilibrium
                                                             considerations often become limiting factors. It is important to
                                                             have a competent source conduct a laboratory-scale treatability
                                                             test to determine whether mass transfer or equilibrium will be
                                                             controlling. The controlling factor is critical to the design of the
                                                             unit and to the determination of whether the technology is
                                                             appropriate for the waste.

                                                                 The extracted organics are removed from the extractor
                                                             with the solvent and go to the separator (3), where the pressure
                                                         Engineering Bulletin: Solvent Extraction Treatment
                                                       460
-------
or temperature is changed, causing the organic contaminants
to separate from the solvent [9, p. 4-2].

    The  solvent is recycled (4)  to  the extractor and the
concentrated contaminants (5) are removed from the separator
[11, P- 6].
Process Residuals

    There are three main product streams generated by this
technology: the concentrated contaminants, the treated soil or
sludge, and the separated water. The extract contains solvent-
free contaminants, concentrated into a smaller volume, for post
treatment.  The recovered contaminants may require analysis
to determine their suitability  for recycle, reuse, or further
treatment before disposal.

    The cleaned soil and solids from treated sludge or sediments
may need to be dewatered, forming a dry solid and a separate
water stream. The volume- of product water depends on the
inherent dewatering capability of the individual process, as well
as the process-specific requirements for feed slurrying. Since
the solvent is an organic material, some residue may remain in
the soil matrix. This can be mitigated by solvent selection, and
if necessary, an additional separation stage. Depending on the
extent of metal or other inorganic contaminants, treatment of
the cleaned solids by some other technique (i.e., stabilization)
may be necessary. Since the  organic component has been
separated, additional solids  treatment should be simplified.
The water  produced should  be analyzed  to  determine  if
treatment is necessary before discharge.

    Solvent extraction units are designed to operate without
air emissions.  However, volatile air emissions could occur
during waste preparation.
                                           Site Requirements

                                               Solvent extraction  units are transported by  trailers.
                                           Therefore, adequate access roads are required to get the unit to
                                           the site.  Typical commercial-scale units, 50-70 tons per day
                                           (tpd), require a setup area of up to 3,600 square feet.

                                               Standard 440V three-phase electrical service is needed.
                                           Water must be available at the site [3]. The quantity of water
                                           needed is vendor and site specific.

                                               Contaminated soils or other waste materials are hazardous
                                           and their handling requires that a site safety plan be developed
                                           to  provide for  personnel protection  and special handling
                                           measures. Storage should be provided to hold the process
                                           product streams until they have been tested to determine their
                                           acceptability for disposal or release. Depending upon the site,
                                           a method to store waste that has been prepared for treatment
                                           may be necessary. Storage capacity will depend on waste
                                           volume.

                                               Onsite analytical equipment for conducting oil and grease
                                           analyses and a gas chromatograph capable of determining site-
                                           specific organic compounds for performance assessment make
                                           the operation more efficient and provide better information for
                                           process control.
                                           Performance Data

                                               The performance data currently available are mostly from
                                           two vendors, CF Systems and Resource Conservation Company
                                           (RCQ.

                                               CF Systems' full-scale 50-tpd commercial unit (PCU 200),
                                           which is treating refinery sludge at Port Arthur, Texas, meets or
                                        Figure 1. Solvent Extraction Process
Excavate
                                   Waste (1)
                                  Preparation
                                                                                      Treated Emissions
                                                                                         Concentrated
                                                                                         Contaminants (5)

                                                                                         Solids
                                                                                         Water
                                                                                         Oversized Rejects
Engineering Bulletin: Solvent Extraction Treatment
-------
exceeds the EPA's Best Demonstrated Available Technology
(BOAT) standards for a number of organic contaminants (Table
3) [3].
                       Table 3
            API Separator Sludge Results*
             (Concentrations In mg/kg)
                                           Treated
                                         Products for
                        feed      BOAT     Land
                    Concentrations  Target    Disposal

Benzene                   30.2        9.5     0.18
Toluene                   16.6        9.5     0.18
Ethylbenzene               30.4       67.0     0.23
Xylenes (Total)              13.2    Reserved     0.98
Anthracene                 28.3        6.2     0.12
Benzo(a)anthracene         BMDL"      1.4     0.18
Benzo(a)pyrene               1.9       0.84     0.33
Bis-<2-ethylhexy)phthalate      4.1        37.0     1.04
Chrysene                    6.3        2.2     0.69
Di-n-butyl phthalate         BMDL        4.2     0.11
Naphthalene                42.2    Reserved     0.66
Phenanthrene               28.6        7.7     1.01
Phenol                    BMDL        2.7    BMDL
Pyrene                      7.7        2.0     1.08

*  This information is from vendor-published literature;
   therefore, quality assurance has not been evaluated.
M Below Minimum Detection Limits (different values in Feed
   and Treated products).
Source: [31 Cf Systems, 50 tpd
    Under the Superfund Innovative Technology Evaluation
(SITE) program, as shown in Table 4, CF Systems demonstrated
an overall PCB reduction of more than 90% for harbor sediments
with inlet concentrations up to 2,575 ppm [11, p. 6].

    A mobile demonstration unit processed different feed
types including clay pit material, ditch skimmer sludge, and
drainage basin soil. The wastes were contaminated with oil and
grease and aromatic priority pollutants.  The oil and grease
were  separated and their concentrations were  reduced to
between 89% and 94% of the original amount For the most
part, the aromatic compounds were reduced to nondetectable
levels [6, p. 10].

    A treatability study completed at the  Conroe, Texas,
Superfund site with the mobile demonstration unit showed
that polynuclear aromatic hydrocarbon (PAH) concentrations
in the soil were reduced 95% from 2,879 ppm to 122 ppm [12,
p. 3-12].

    The only available data for the on-line operational availability
were  from CF Systems, which  they estimated to be 85%
(corresponding to a treatment process downtime of 15%). This
can be verified and possibly improved with increased operating
experience.
    The ability of RCC's full- scale B.E.S.T.™ process to separate
oily feedstock into product fractions was evaluated by the EPA
at the General Refining Superfund site near Savannah, Georgia,
in February 1987.  It is an abandoned waste oil re-refining
facility that contained four acidic oily sludge ponds with high
levels of heavy metals (Pb=200-10,000 ppm, Cu=83-190 ppm)
and detectable PCBs (2.9-5 ppm). The average composition of
the sludge from the four lagoons was 10% oil, 20% solids, and
70% water by weight [16, p. 13].  The transportable 70 tons/
day B.E.S.T.™ unit processed approximately 3,700 tons of
sludge at the General Refining Site. The treated solids from this
unit were back filled to the site, product oil was recycled as a fuel
oil blend, and the recovered water was pH adjusted and
transported to a local industrial wastewater treatment facility.

    Test results (Table 5) showed that the heavy metals were
mostly concentrated in the solids product fraction. TCLP test
results showed heavy metals to be in stable forms that resisted
leaching, illustrating a potential beneficial side  effect when
metals are treated by the process [1, p. 13].

    RCC has bench-scale treatability data on  a variety of
wastes, including steel mill wastewater treatment sludge and
oil refinery sludge (Table 6) [1, p. 12], that will illustrate the
degree of separation possible among the oil, water, and solids
                       Table 4
        New Bedford Harbor Sediments Results
               (Concentrations In ppm)




Testi
1
2
3


Initial
KB
Concentration
350
288
2,575


Final
KB
Concentration
8
47
200



Percent
Reduction
98
84
92
Number
of
Passes
Through
Extractor
9
1
6
 Source [11J, CF Systems, 1.5 gpm
                        Tables
          EPA Data from the General Refining
             Superfund Site, Savannah, GA



Metals
As
Ba
Cr
Pb
Se

initial
Concentration
(mg/kg)
<0.6
239
63.
3,200
<4.0
Product
Solids
Metal
(ppm)
<5.0
410
21
23,000
<5.0

TCLP
Levels
(ppm)
<0.0
<0.03
<0.05
5.2
0.008
   Source: [1L RCC, 100 tpd
                                                          Engineering Bulletin: Solvent Extraction Treatment
                                                         462
-------
components  of  the waste.  The separation of PCBs in
contaminated harbor sediments is shown in Table 7 and in a
variety of matrices in Table 8. Results of treatment of pesticide-
contaminated soils are shown in Table 9.

    RCRA Land  Disposal  Restrictions  (LDRs)  that require
treatment of wastes to BOAT levels prior to land disposal may
sometimes be determined to  be applicable or relevant  and
appropriate requirements (ARARs) for CERCLA response actions.
The solvent extraction technology can produce a treated waste
that meets treatment levels set by BOAT, but may not reach
these treatment levels in all cases. The ability to meet required
treatment levels is dependent  upon  the specific waste
constituents and  the waste matrix.  In cases where solvent
extraction does not meet these levels, it still may, in certain
situations, be selected for use at the site if a treatability variance
establishing alternative treatment levels is obtained. EPA has
                       Tabled
               OH and Grease Removal
                     Bench Scale


Original Sludge
Concentration
Oil%
Water %
Solids %
product Stream
Oil
Water %
Solvent (ppm)
Water
Oil & Crease (ppm)
Solvent (ppm)
Solid
Oil & Crease (ppm)
Solvent (ppm)
StedMIII
Sludge


11
33
56


<2
<100

<100
11

0.2
34
Refinery
Sludge


8
77
15


<1
<150

<100
12

0.9
N/A
     Source RCC, 6 kg Batch
                        Table?
                   Harbor Sediments
             PCB Extraction — Bench Scale
Original Sediments
Product Stream
Oil
Water
Solid
% Removal
4,500 ppm
75,000 ppm
lOppb
<1opm
>99%
       Source: RCC, 6 kg Batch
made the treatability variance process available in order to
ensure that  LDRs do not unnecessarily  restrict the  use of
alternative and innovative treatment technologies. Treatability
variances may be justified for handling complex soil and debris
matrices. The following guides describe when and how to seek
a treatability variance for soil and debris: Superfund LDR Guide
#6A, "Obtaining a Soil and  Debris Treatability Variance for
Remedial Actions" (OSWER Directive 9347.3-06FS) [17], and
Superfund LDR Guide #6B, "Obtaining  a Soil and  Debris
Treatability Variance for Removal Actions" (OSWER Directive
9347.3-07FS) [18]. Another approach could be to use other
treatment techniques in series with solvent extraction to obtain
desired treatment levels.
Technology Status

    During 1989, solvent extraction technology was selected
as the remedial action to clean up 2,000-2,200 cubic yards of
soil contaminated with PCBs and organics at the Pinette
Salvage Superfund site in Washbum, Maine [13, p. 2]. In 1989,
solvent extraction was also selected as the source  control
remedy in the following Records of Decision: F. O'Connor
Superfund site in Augusta, Maine; the Norwood PCBs Superfund
site in Norwood, Massachusetts; the Ewan Property Superfund
site in Shamong, New Jersey; United Creosoting in Conroe,
Texas; and Outboard Marine, State of Illinois [19].

    The most significant factors influencing costs are the waste
volume, the number of extraction stages, and the operating
parameters such as labor, maintenance, setup, decontamination,
demobilization, and  lost time  resulting from equipment
operating delays. Extraction efficiency can be influenced by
process parameters such as solvent used, solvent/waste ratio,
throughput rate, extractor residence time, and  number of
extraction stages. Thus, variation of these parameters in a
particular hardware design and/or configuration will influence
the treatment  unit cost component,  but should not be a
significant contributor to the overall site costs.

    Cost estimates for this technology range from $100 to
$500 per ton.
Solvent Extraction Systems

    Solvent extraction systems are at various  stages of
development The following is a brief discussion of six systems
that have been identified.

    CF Systems uses liquefied hydrocarbon gases such as
propane  and  butane as  solvents for separating organic
contaminants from soils, sludges, and sediments. The extraction
units are liquid-filled systems that employ pumps to move the
material through the system.  As such, the feed  material is
pretreated, through the addition of water, to ensure the
"pumpability" of the material [10, p. 12]. The pH of the feed
may be adjusted, through  the addition of lime or a similar
material, to maintain the metallurgical integrity of the system.
Typically, the feed material  is screened to remove particles of
greater than 1 /8" diameter.  Depending upon the nature of the
Engineering Bulletin: Solvent extraction Treatment
-------
                                                      Table 8
                            PCB Samples Tested In RCC's Laboratory (1/87 through 7/88)
Client
SLUDGES
CRI
GUI
GUI
Superfund Site Sh
Superfund Site CO "A"
Superfund Site CO "B"
Superfund Site CO "C"
SEDIMENTS
River Sediment "B"
Superfund B (#13)
Harbor Sediment "B"
Harbor Sediment *C*
Harbor Sediment "D"
Harbor Sediment NB-A
Harbor Sediment NB-B
SOILS
Industrial Soil A
Industrial Soil B
Industrial Son D
Industrial Sofl |
As Received
PCB
(mg/kg)

5.9
4.7
S.3
106
51
21
11

960
83
20,000
30,000
430
5,800
16,500

250
120
5,300
19
Raw Sample Phase Composition
Oil% Water % Solids %

27 66 7
10 58 32
13 57 30
35 44 21
49 28 23
23 24 53
15 16 69

26 17 83
44 40 16
3 22 75
5.6 62 32
0.38 47 53
1.9 69 29
4.3 51.6 44.1

0.06 9.4 91
0.06 13 87
1.0 19 80
.09 16 84
PCBs In Product Fraction
Oil Water Solids % Removal
(mg/kg) (mg/kg) (mg/kg)

9.3 <.005 <.01 99.9%
N/A <-01 0.015 99.9%
N/A <.01 0.14 99.2%
270 N/A 1.0 99.8%
80 N/A 0.44 99.8%
71 N/A 0.08 99.8%
52 N/A 0.06 99.6%

>:/A N/A 40 96.5%
N/A N/A 1.0 99.8%
970,000 <006 27 99.9%
550,000 N/A 94 99.9%
N/A N/A 32 96.0%
280,000 <005 35 99.4%
360,000 <.005 75 99.8%

120,000 N/A 2.2 99.1%
280,000 N/A 6.4 94.7%
370,000 N/A 11 99.8%
10,000 N/A 0.7 96.3%
    Source: RCC, .6 kg Batch
oversize material, the large particles may be reduced in size and
then returned to the extraction unit for processing.

    CF Systems' extraction technology has been demonstrated
in the field at two Superfund sites and approximately 10
refineries and treatment, storage, and disposal (TSD) facilities
to date.

    CF Systems' solvent extraction technology is available in
several commercial sizes and the Mobile Demonstration Unit is
available for onsite treatability studies. To date, CF Systems has
supplied  three  commercial-scale extraction units for the
treatment of a  variety of wastes [12, p.  3-12].   A 60-tpd
treatment system was designed to extract organic liquids from
a broad range of hazardous waste feeds at ENSCO's El Dorado,
Arkansas, incinerator facility.  A commercial-scale extraction
unit is being installed at a facility in Baltimore, Maryland, to
remove organic contaminants from a 20-gpm wastewater
stream. A PCU-200 extraction unit is installed and operating at
the Star Enterprise (Texaco) refinery in Port Arthur, Texas. This
unit b designed to treat listed refinery wastes to meet or exceed
the EPA's BOAT standards. Performancedataandthetechnology
status are explained in the body of this bulletin.
    RCCs B.E.S.T.™ system uses aliphatic amines (typically
triethylamine) as  the solvent to separate and recover
contaminants [1, p. 2]. It is applicable to soils, sludges, and
sediments, and in batch mode of operation does not need a
pumpable waste. Before the extraction process is begun, feed
materials are screened to remove particles of greater than 1"
diameter and pH adjusted to an alkaline condition. The process
operates at or near ambient temperature and  pressure.
Triethylamine can be recycled from the recovered liquid phases
via steam stripping because of its high vapor pressure and low
boiling point azeotrope formation.

    RCC has a transportable B.E.S.T.™ pilot-scale unit available
to treat soils and sludges. This pilot-scale equipment has been
used at a gulf coast refinery  treating various refinery waste
streams and has treated PCB-contaminated soils at an industrial
site in Ohio in November 1989. A full-scale unit with a nominal
capacity of 70 tod was used to clean up 3,700 tons of PCB-
contaminated  petroleum  sludge  at the  General Refining
Superfund Site in Savannah, Georgia, in 1987.  Performance
data and the technology status are explained in the body of this
bulletin.
                                                         Engineering Bulletin: Solvent Extraction Treatment
-------
    ENSR is in the process of developing a mobile solvent
extraction unit capable of decontaminating soils and sludges at
a rate of 5 to 10 cubic yards/hour [5, p. 1 ]. The ENSR system
uses a proprietary reagent and solvent The company claims
that its solvent extraction system is designed to operate without
significant pretreatment of the soil/sludge and without the
addition or removal of water. Design of a pilot-scale unit is near
completion.  Thus far, only performance data from earlier
bench-scale tests  are available.

    The Extraksol™ process was developed in 1984 by Sanivan
Croup, Montreal, Canada [7, p. 35]. It is applicable to soils,
sludges, and sediments. Performance data on contaminated
soils and refinery wastes are available for a 1 ton per hour (tph)
mobile unit  The process uses a  proprietary solvent  that
reportedly achieved removal efficiencies up to 99% (depending
on the number of extraction cycles and the type of soil) on
PCBs, oil, grease, PAHs, and pentachlorophenol [7, p. 45]. The
1 -tph unit is suitable for small projects with a maximum of 300
tons of material to be treated.  The Sanivan group is planning
to build a full-scale unit that can process 6-8 tph of waste [7, p.
41].

    Harmon  Environmental  Services  and  Acurex
Corporation are involved in a cooperative joint venture to
develop a solvent soil washer/extraction system appropriate for
the onsite remediation of Superfund and RCRA sites. They have
completed  EPA-sponsored bench-scale  studies  on different
types of soils contaminated with #2 fuel oil. The design of a pilot
plant unit is being considered.
    The Low Energy Extraction Process (LEEP) is a patented
solvent  extraction process that  can be  used onsite for
decontaminating soils, sludges, and sediments.   LEEP uses
common hydrophilic and hydrophobia organic solvents to
extract and further concentrate organic pollutants such as PCBs
[2, p. 3].  Bench-scale studies are available. The design of the
pilot plant is completed, and the plant is scheduled for operation
at the beginning of 1990.
EPA Contact

    Technology-specific questions regarding solvent extraction
may be directed to:

    Michael Cruenfeld
    U.S. EPA,  Risk Reduction Engineering Laboratory
    CSA Raritan Depot
    Woodbridge Avenue
    Edison, New Jersey 08837
    FTS 340-6625
    (201)321-6625
                       Table 9
           RCC B.E.S.T.™ Treated Pesticide-
          Contaminated Soli — Bench Scale
Analyte
p,p'-DDT
p/P'-DDE
p,p'-DDD
Endosulfan-l
Endosutfan-ll
Endrin
Dieklrin
Toxaphene
BHC-Beta
BHC-Camma
(Undane)
Pentachlorophenol
feedstock
(ppm)
. 500
84
190
250
140
140
37
2,600
<30

<30
150
Product
Solids
(ppm)
0.2
0.5
0.05
<0.02
<0.02
0.02
<0.02
0.9
<0.13

<0.07
1.9
Removal
ffflc/ency%
99.96
99.4
99.97
>99.99
>99.99
99.99
>99.95
99.97
-

-
98.7
                                                            3.
                                                            4.
                                                            5.
  Source: RCC, .6 kg Batch
                 REFERENCES
     Austin, Douglas A.  The B.E.S.T.™ Process — An
     Innovative and Demonstrated Process for Treating
     Hazardous Sludges and Contaminated Soils. Presented
     at 81st Annual Meeting of APCA, Preprint 88-6B.7,
     Dallas, Texas, 1988.
     Blank, Z., B. Rugg, and W. Steiner.  LEEP-Low Energy
     Extraction Process:  New Technology to Decontaminate
     PCB-Contaminated Sites, EPA SITE E02 Emerging
     Technologies Program. Applied Remediation
     Technology, Inc., Randolph, New jersey, 1989.
     CF Systems Corporation, Marketing Brochures (no
     dates).
     Hall, Dorothy W., ] A Sandrin, R.L McBride. An
     Overview of Solvent Extraction Treatment
     Technologies. Presented at AICHE Meeting,
     Philadelphia, Pennsylvania, 1989.
     Massey, M.|., and S. Darian. ENSR Process for the
     Extractive Decontamination of Soils and Sludges.
     Presented at the PCB Forum, International Conference
     for the Remediation of PCB Contamination, Houston,
     Texas, 1989.
 Engineering Bulletin: Solvent Extraction Treatrnept
-------
                                               REFERENCES
6.   Moses, John M., R. Abrishamian. Use of Liquified Gas
     Solvent Extraction in Hazardous Waste Site Closures.
     Presentation Paper No. 5SD, Presented at AICHE
     Summer National Meeting, Denver, Colorado, 1988.
7.   Paquin,)., and 0. Mourato.  Soil Decontamination with
     Extraksol. Sanivan  Croup, Montreal, Canada (no date),
     pp. 35-47.
8.   Reilly, T.R., S. Sundaresan, and J.H. Highland. Cleanup
     of PCB Contaminated Soils and Sludges By A Solvent
     Extraction Process:  A Case Study. Studies in
     Environmental Science, 29:125-139,1986.
9.   Rowe, C.  Evaluation of Treatment Technologies for
     Listed Petroleum Refinery Wastes, Chapter 4. API
     Waste Technologies Task Force, Washington, DC,
     1'87.  pp. 1-12.
10.  Technology Evaluation Report — CF Systems Organics
     Extraction System,  New Bedford, MA, Volume I.
     Report to be published, U.S. Environmental Protection
     Agency.
11.  Technology Evaluation Report — CF Systems Organics
     Extraction System,  New Bedford, MA, Volume II.
     Report to be published, U.S. Environmental Protection
     Agency.
12.  Applications Analysis Report — CF Systems Organics
     Extraction System,  New Bedford, MA, Report to be
     published, U.S. Environmental Protection Agency.
13.  Innovative Technology: B.E.S.T.™ Solvent Extraction
     Process.  OSWER Directive 9200.5-253FS, U.S.
     Environmental Protection Agency, 1989.
                14.  Raghavan, R., D.H. Dietz, and E. Coles. Cleaning
                     Excavated Soil Using Extraction Agents: A State-of-the-
                     art Review.  EPA 600/2-89/034, U.S. Environmental
                     Protection Agency, Releases Control Branch, Edison, NJ,
                     1988.
                15.  Technology Screening Guide for Treatment of CERCLA
                     Soils and Sludges. EPA/540/2-88/004, U.S.
                     Environmental Protection Agency, 1988.
                16.  Evaluation of the B.E.S.T.™ Solvent Extraction Sludge
                     Treatment Technology Twenty-Four Hour Test EPA/
                     600/2-88/051, U.S.  Environmental Protection Agency,
                     1988.
                17.  Superfund LDR Guide #6A: Obtaining a Soil and Debris
                     Treatability Variance for Remedial Actions.  OSWER
                     Din .tive 9347.3-06FS,  U.S. Environmental Protection
                     Agency, 1989.
                18.  Superfund LDR Guide #6B: Obtaining a Soil and Debris
                     Treatability Variance for Removal Actions. OSWER
                     Directive 9347.3-07FS,  U.S. Environmental Protection
                     Agency, 1989.
                19.  ROD Annual Report, FY1989. EPA/540/8-90/006, U.S.
                     Environmental Protection Agency, 1990.
                20.  Weimer, LD. The B.E.S.T.™ Solvent Extraction Process
                     Applications with Hazardous Sludges, Soils and
                     Sediments.  Presented at the Third International
                     Conference, New Frontiers for Hazardous Waste
                     Management, Pittsburgh, Pennsylvania, 1989.
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