EPA 540-2-91-021
                              United States
                              irwironmertsl Protection
                             Office of Emergency and
                             Remedial  Response
                             Washington, DC 20460
Office of
Research and Development
Cincinnati, OH 45268
October 1991
Engineering Bulletin
In  Situ  Soil   Flushing

     Section 121(b) of the Comprehensive Environmental Re-
 sponse, 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 maxi-
 mum extent practicable"  and to prefer remedial actions in
 which  treatment "permanently and significantly reduces the
 volume, toxicity, or mobility of hazardous substances, pollut-
 ants, and contaminants as a principal element." The Engineer-
 ing 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 char-
 acteristics needed to evaluate a technology for potential appli-
 cability to their Superfund or other hazardous waste site.  Those
 documents that describe individual treatment technologies fo-
 cus on remedial investigation scoping needs.  Addenda will be
 issued periodically to update the original bulletins.

    In situ soil flushing is the extraction of contaminants from
the soil with water or other suitable aqueous solutions. Soil
flushing is accomplished by passing the extraction fluid through
in-place soils using an injection or infiltration process. Extraction
fluids must be recovered and, when possible, are recycled. The
method is potentially applicable to all types of soil contami-
nants. Soil flushing enables removal of contaminants from the
soil and is  most effective in permeable soils.  An effective
collection system is required to prevent migration of contami-
nants and potentially toxic extraction fluids to uncontaminated
areas of the aquifer.  Soil flushing, in conjunction with in situ
bioremediation, may be a cost-effective means of soil remedia-
tion at certain sites [1, p. vi] [2, p.  11].* Typically, soil flushing
is used in conjunction with other treatments that destroy con-
taminants  or remove  them from  the extraction fluid and

    Soil flushing is a developing technology that has had lim-
ited use in the United  States. Typically, laboratory and field
treatability studies must be performed under site-specific condi-
tions before soil flushing is selected as the remedy of choice. To
* [reference number, page number]
                              date, the technology has been selected as part of the source
                              control  remedy at 12 Superfund sites.  This technology is
                              currently operational at only one Superfund site; a second is
                              scheduled to begin operation in 1991 [3][4].  EPA completed
                              construction of a  mobile soil-flushing system,  the In Situ
                              Contaminant/Treatment Unit, in 1988. This mobile soil-flush-
                              ing system is designed for use at spills and uncontrolled hazard-
                              ous waste sites [5].

                                  This bulletin provides information on the technology appli-
                              cability, the technology limitations,  a description of the tech-
                              nology, the types of residuals resulting from the use of the
                              technology, site requirements, the latest performance data, the
                              status of the technology, and sources of further information.
                              Technology Applicability

                                  In situ soil flushing is generally used in conjunction with
                              other treatment technologies such as activated carbon, biodeg-
                              radation, or chemical precipitation to treat contaminated
                              groundwater resulting from soil flushing.  In some cases,  the
                              process can reduce contaminant concentrations in the soil to
                              acceptable levels, and thus serve as the only soil treatment
                              technology. In  other cases, in situ biodegradation or other in
                              situ technologies can be used in conjunction with soil flushing
                              to achieve acceptable contaminant removal efficiencies.  In
                              general, soil flushing is effective on coarse sand and gravel
                              contaminated  with a wide range of organic, inorganic, and
                              reactive contaminants. Soils containing a large amount of clay
                              and silt may not respond well to soil flushing, especially if it is
                              applied as a stand-alone technology.

                                  A number of chemical contaminants can be removed from
                              soils using soil  flushing.  Removal  efficiencies depend on the
                              type of contaminant as well as the type of soil. Soluble (hydro-
                              philic) organic contaminants often are easily removed from soil
                              by flushing with water alone. Typically, organics with octanol/
                              water partition coefficients (Kow) of less than 10 (log Kow<1) are
                              highly soluble.  Examples of such compounds include  lower
                              molecular weight alcohols, phenols, and carboxylic acids [6].

                                  Low solubility (hydrophobic) organics may be removed by
                              selection  of a  compatible surfactant [7].   Examples of such
                              compounds include chlorinated pesticides, polychlorinated bi-
                              phenyls (PCBs), semivolatiles (chlorinated benzenes and poly-
                              nuclear aromatic hydrocarbons), petroleum products (gasoline,

jet  fuel, kerosene, oils  and  greases), chlorinated solvents
(trichloroethene), and aromatic solvents (benzene, toluene, xy-
lenes and ethylbenzene) [8].  However, removal of some of
these chemical classes has not yet been demonstrated.

     Metals may require  acids, chelating agents, or reducing
agents for successful soil flushing.  In some cases, all three types
of chemicals may be used in sequence to improve the removal
efficiency of metals [9].  Many inorganic metal  salts, such as
carbonates of nickel, zinc, and copper, can be flushed from the
soil with dilute acid solutions [6].  Some inorganic salts such as
sulfates and chlorides can be flushed with water alone.

     In situ soil flushing has been considered for treating soils
contaminated with hazardous wastes,  including pentachloro-
phenol and creosote from wood-preserving operations, organic
solvents, cyanides and heavy metals from electroplating resi-
dues, heavy metals from some paint sludges, organic chemical
production residues, pesticides and pesticide production resi-
dues, and petroleum/oil residues [10, p. 13][11, p. 8][7][12].

     The effectiveness of  soil flushing for general contaminant
groups [10, p. 13] is shown in Table 1.  Examples of constitu-
ents within contaminant  groups are provided in Reference 10,
"Technology  Screening Guide For Treatment of  CERCLA Soils
and Sludges." Table 1  is  based on currently available informa-
tion or  professional judgment where definitive information is
                         Table 1
        Effectiveness of Soil Flushing on General
                  Contaminant Groups
     Contaminant Croups
     Halogenated volatile*
     Halogenated semivolatiles
     Nonhalogenated volatiles
     Nonhalogenated semivolatiles
     Pesticides (halogenated)
     Organic cyanides
     Organic corrosives
     Volatile metals
     Nonvolatile metals
     Radioactive materials
     Inorganic corrosives
     Inorganic cyanides







   Demonstrated Effectiveness:  Successful treatability  test at  some scale
 T  Potential Effectiveness: Expert opinion that technology will work.
 J  No Expected Effectiveness: Expert opinion that technology will not work.
currently inadequate or unavailable. The demonstrated effec-
tiveness of the technology for a particular site or waste does not
ensure that it will be effective at all sites or that the treatment
efficiency achieved  will be acceptable at other sites. For the
ratings used  in this table, demonstrated effectiveness means
that, at some scale,  treatability was tested to show that, for that
particular contaminant and matrix, the technology was effec-
tive.  The ratings of potential effectiveness and  no expected
effectiveness are based upon expert judgment. Where poten-
tial 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.  Other
sources of general observations and average removal efficien-
cies for different treatability groups are  the Superfund LDR
Guide #6A, "Obtaining a Soil and Debris Treatability Variance
for Remedial Actions" (OSWER  Directive 9347.3-06FS)  [13],
and Superfund LDR Guide #6B,  "Obtaining a Soil and Debris
Treatability Variance for Removal  Actions" (OSWER Directive

    Information on cleanup objectives, as well as the physical
and chemical characteristics of the site  soil and its contami-
nants, is necessary to  determine the potential performance of
this technology. Treatability tests are also required to determine
the feasibility of the specific soil-flushing process being consid-
ered.  If bench-test results are promising, pilot-scale demonstra-
tions should be conducted before making a final commitment
to full-scale  implementation.  Table 2  contains physical and
chemical soil characterization parameters that should be estab-
lished before a treatability test is  conducted at a specific site.
The table contains  comments relating to the purpose of the
specific parameter to  be characterized and its impact on the
process [15, p. 71 5] [16, p. 90] [1 7].

    Soil permeability is a key physical parameter for determin-
ing the feasibility of using a soil-flushing process.   Hydraulic
conductivity (K) is measured to assess the permeability of soils.
Soils with low permeability (K < 1.0 x 10"5 cm/sec) will limit the
ability of  flushing  fluids to  percolate through  the soil  in  a
reasonable time frame. Soil flushing is most likely to be effective
in permeable soils (K >  1.0 x 103 cm/sec), but may have limited
application to less permeable soils (1.0 x 10"5 cm/sec < K < 1.0 x
10'3 cm/sec). Since there can be significant lateral and vertical
variability in soil permeability, it is important that field measure-
ments be made using the appropriate methods.

    Prior to field implementation of soil flushing, a  thorough
groundwater hydrologic study should  be carried out.   This
should include  information on seasonal  fluctuations in  water
level, direction of groundwater flow, porosity, vertical and hori-
zontal hydraulic conductivities, transmissivity and infiltration
(data  on rainfall, evaporation, and percolation).

    Moisture content can affect the amount of flushing fluids
required.  Dry soils  will require more flushing fluid initially to
mobilize contaminants. Moisture content is also used to calcu-
late pore volume to  determine the rate of treatment [15].

    The  concentration and distribution of organic  contami-
                                                                         Engineering Bulletin: In Situ Soil Flushing

                          Table 2
               Characterization Parameters

   Soil permeability

      >1.0x 10'3 cm/sec
      <1.0x 10s cm/sec

   Soil structure

   Soil porosity

   Moisture content

   Groundwater hydrology

    Solubility products
    Reduction potential
    Complex stability

   Total Organic Carbon
   Clay content
   Cation Exchange
   Capacity (CEC)

   pH, buffering
Purpose and Comment

Affects treatment time and
efficiency of contaminant removal   l
  Effective soil flushing
  Limited soil flushing

Influences flow patterns
  (channeling, blockage)

Determines moisture capacity of soil
at saturation (pore volume)

Affects flushing fluid transfer

Critical in controlling the recovery
of injected fluids and contaminants

Determine contaminants and
assess flushing fluids required,
flushing fluid compatibility,
changes in flushing fluid with
changes in contaminants.

Concentration and species of cons-
tituents will determine flushing fluid
compatibility, mobility of metals,
post treatment.
Adsorption of contaminants on
soil increases with increasing TOC.
Important in marine wetland sites,
which typically have high TOC.

Adsorption of contaminants on soil
increases with increasing clay

May affect treatment of metallic

May affect treatment additives
required, compatibility with
equipment materials of construc-
tion, wash fluid compatibility.
nants and metals are key chemical parameters. These param-
eters determine the type and quantity of flushing fluid required
as well as any post-treatment requirements. The solubility and
partition coefficients of organics in water or other solutions are
also important in  the selection of the proper flushing  fluids.
The species of metal compounds present will affect the solubil-
ity and leachability of heavy metals.
     High humic content and high cation exchange capacity
tend to reduce the removal efficiency of soil flushing.  Some
organic contaminants may adsorb to humic materials or clays
in soils and, therefore, are difficult to remove during soil flush-
ing.  Similarly, the binding of certain metals with clays due to
cationic exchange makes them difficult to remove with soil
flushing.  The buffering  capacity of the  soil  will affect the
amount required of some additives, especially acids.  Precipita-
tion reactions (resulting in clogging of soil pores) can occur due
to pH changes in the flushing fluid caused by the neutralizing
effect of soils with high buffering capacity.  Soil pH can affect
the speciation of metal compounds resulting in  changes in the
solubility of metal compounds in the flushing fluid.

    Generally, remediation times with this technology will be
lengthy (one to  many years) due to the slowness of diffusion
processes in the liquid phase.  This technology requires hydrau-
lic control  to avoid movement of contaminants offsite.  The
hydrogeology of some sites may make this difficult or impos-
sible to achieve.

    Contaminants in soils containing a high percentage of silt-
and  clay-sized particles  typically are strongly adsorbed  and
difficult to remove.  Also, soils with silt and clay tend to be less
permeable.  In such cases, soil flushing generally should not be
considered as a stand-alone technology.

    Hydrophobic contaminants generally require surfactants
or organic solvents for their removal from soil.  Complex mix-
tures of contaminants in the  soil (such as a mixture of metals,
nonvolatile organics, and semivolatile organics) make it difficult
to formulate 
Technology Description

    Figure 1 is a general schematic of the soil flushing process [18, p.
7].  The flushing fluid  is applied (1)  to the contaminated soil by
subsurface injection wells, shallow infiltration galleries, surface flood-
ing, or above-ground sprayers.  The flushing fluid is typically water
and may contain additives to improve contaminant removal.

    The flushing fluid percolates through the contaminated soil,
removing contaminants as it proceeds. Contaminants are mobi-
lized by solubilization into the flushing fluid, formation of emul-
sions, or through chemical reactions with the flushing fluid [19].

    Contaminated flushing fluid or leachate mixes with ground-
water and is collected (2) for treatment. The flushing fluid
delivery and the groundwater extraction systems are designed
to ensure complete contaminant recovery [7].  Ditches open to
the surface, subsurface collection drains, or groundwater recov-
ery wells may be used to collect flushing fluids and mobilized
contaminants.  Proper design of a fluid recovery system is very
important to the effective application of soil flushing.

    Contaminated groundwater and flushing fluids are  cap-
tured and pumped to the surface  in a  standard groundwater
extraction well (3).   The rate of groundwater withdrawal is
determined by the flushing fluid delivery rate, the natural infil-
tration  rate, and the groundwater hydrology. These will deter-
mine the extent to which the groundwater removal rate must
exceed the flushing fluid delivery rate to ensure recovery of all
reagents and mobilized contaminants.  The  system must  be
designed so that hydraulic control is maintained.

    The groundwater and  flushing fluid are  treated (4) using
the appropriate wastewater treatment  methods.  Extracted
groundwater is treated to reduce the heavy metal content,
organics, total suspended  solids,  and other  parameters  until
they meet regulatory requirements.  Metals may be removed
by lime  precipitation or by other technologies compatible with
the flushing reagents used. Organics are removed with acti-
vated carbon, air stripping, or other appropriate technologies.
Whenever possible, treated water should be recycled as makeup
water at the front end of the soil-flushing process.

    Flushing additives (5) are added,  as  required,  to  the
treated  groundwater, which is recycled for use as flushing
fluid.  Water alone is used to remove hydrophilic organics and
soluble  heavy-melal  salts [9].  Surfactants may be added to
remove hydrophobic and slightly hydrophilic organic  con-
taminants  [12]. Chelating  agents,   such  as  ethylene-
diaminetetra-acetic acid (EDTA),  can effectively remove cer-
tain metal compounds. Alkaline  buffers such as tetrasodium
pyrophosphate can remove metals bound to the soil organic
fraction. Reducing agents  such as hydroxylamine hydrochlo-
ride can reduce iron and  manganese oxides that can  bind
                                                        Figure 1
                                           Schematic of Soil Flushing System
                            Spray Application
                                                         Contaminated Area
                                                                                     Extraction Well
                                                                                                      Low Permeability
                                                                       Engineering Bulletin: In Situ Soil Flushing

metals in soil.  Insoluble heavy-metal compounds also can be
reduced or oxidized to more soluble compounds.  Weak acid
solutions can improve the solubility of certain heavy metals
[9]. Treatability studies should be conducted to determine
compatability of the flushing reagents with the contaminants
and with the site soils.
Process Residuals

    The primary waste stream generated is contaminated flush-
ing fluid, which is recovered along with groundwater.  Recov-
ered flushing fluids may need treatment to meet appropriate
discharge standards prior to release to a local, publicly-owned
wastewater treatment works or receiving streams. To the maxi-
mum extent practical, this water should be  recovered  and
reused in the flushing process.  The separation of surfactants
from recovered flushing fluid, for reuse in the process, is a major
factor in the cost of soil flushing. Treatment of the flushing fluid
results in process sludges  and residual solids, such as spent
carbon and spent ion exchange resin, which must be appropri-
ately treated before disposal. Air emissions of volatile contami-
nants from recovered  flushing fluids should be collected  and
treated, as appropriate, to meet applicable regulatory standards.
Residual  flushing additives  in the soil may  be  a concern  and
should be evaluated on a site-specific basis.
Site Requirements

    Access roads are required for transport of vehicles to and
from the site. Stationary or mobile soil-flushing process systems
are located on site.  The exact area required will depend on the
vendor  system  selected and the number of tanks or ponds
needed  for washwater preparation and wastewater treatment.

    Because  contaminated flushing  fluids are usually consid-
ered hazardous, their handling requires that a site safety plan be
developed to provide for personnel protection and special han-
dling measures during wastewater treatment  operations. Fire
hazard and explosion considerations should  be minimal,  since
the soil-flushing fluid is predominantly water.

    An  Underground Injection Control (DIG) Permit may be
necessary if subsurface infiltration galleries or injection wells are
used. When groundwater is not recycled,  a National Pollution
Discharge Elimination System (NPDES) or State Pollution Dis-
charge  Elimination System (SPDES)  permit may be required.
Federal, State, and  local  regulatory  agencies should be con-
tacted to  determine permitting requirements before imple-
menting this technology.

     Slurry walls or other containment structures may be needed
along with hydraulic controls to ensure capture of contaminants
and flushing additives. Climatic conditions such as precipitation
cause surface runoff and water infiltration. Berms, dikes, or other
runoff control methods may be required.  Impermeable mem-
branes may be necessary  to limit infiltration of precipitation,
which could cause dilution of flushing solution and loss of hy-
draulic control. Cold weather freezing must also be considered
for shallow infiltration galleries and above-ground sprayers.
Performance Data

    Some of the data presented for specific contaminant re-
moval  effectiveness  were obtained from  publications devel-
oped by the respective soil-flushing-system vendors. The qual-
ity of this information has not been determined; however  it
does give an  indication  of the  effectiveness of in  situ  soil

    Tetrachloroethylene was discharged into the aquifer at the
site of a  spill in Sindelfingen, Germany.  The contaminated
aquifer is a high-permeability (k=5.10 x 10"4 m/sec) layer over-
laying a clay barrier.  Soil flushing was accomplished by infiltrat-
ing water into the ground  through ditches. The leaching liquid
and polluted groundwater were pumped out of eight wells and
treated with activated carbon.  The treated water was recycled
through the infiltration ditches.  Within 18 months, 17 metric
tons of chlorinated hydrocarbons were recovered [19, p. 565].

    Two percolation basins were installed to flush contami-
nated soil at the United Chrome Products site near Corvallis,
Oregon.   Approximately 1,100  tons of soil containing  the
highest chromium concentrations were excavated  and  dis-
posed of offsite. The resulting pits from the excavations were
used as infiltration basins to flush the remaining contaminated
soil.  The soil-flushing operation for the removal of hexavalent
chromium from an estimated 2.4 million gallons of contami-
nated groundwater began in August 1988. No information on
the site soils was provided, but preliminary estimates were that
a groundwater equilibrium concentration of 100 mg/L chromium
would be reached in 1 to 2 years, but that final cleanup to 10
mg/L would take up to 25 years [20, p.  H-1 ]. Since that time
over 8-million gallons of groundwater, containing over 25,000
pounds of chromium, have been removed from the 23 extrac-
tion wells in the shallow aquifer.  Average monthly chromium
concentrations in the groundwater decreased from 1,923 mg/
L in August 1988 to 96 mg/L in March 1991 [4].

    Waste-Tech Services, Inc. performed  two  tests of soil-
flushing techniques to remove creosote contamination at the
Laramie Tie Plant site in Wyoming. The first test involved slowly
flooding  the  soil surface  with water to perform primary oil
recovery  (POR).  Soil flushing reduced the average concentra-
tion  of total  extractable  organics (TEO)  from  an estimated
initial concentration  of 93,000 mg/kg to 24,500 mg/kg, a 74
percent reduction. The second test involved sequential treat-
ment with alkaline agents, polymers, and surfactants. During
the 8-month treatment period, average TEO concentrations
were reduced to 4,000 mg/kg. This represents an 84 percent
reduction from the  post-POR concentration (24,500 mg/kg)
and a 96 percent reduction from the estimated initial concen-
tration (93,000 mg/kg).  The  tests were performed in alluvial
sands and gravels.  The low permeability of adjacent silts and
clays precluded soii flushing [22].

    Laboratory tests were conducted  on contaminated soils
from  a fire-training area at Volk  Air Force  Base.  Initial
concentrations of oil and grease in the soils were reported to be
10,000 and 6,000 mg/kg. A 1.5-percent surfactant solution in
water was used to flush soil columns.  The tests indicated that
75 to  94 percent of  the initial  hydrocarbon contamination
could be removed by flushing with 12-pore volumes of liquid.
Engineering Bulletin: In Situ Soil Flushing

However, field tests were unsuccessful in removing the same
contaminants.  Seven soil-flushing solutions, including the solu-
tion tested in the laboratory studies, were tested in field studies.
The flushing solutions were delivered to field test cells measur-
ing 1 foot deep and 1 to 2 feet square. Only three of the seven
tests achieved the target delivery of 14-pore volumes.  Two of
the test cells plugged completely, permitting no further infiltra-
tion of flushing solutions. There was no statistically significant
removal of soil contaminants due to soil flushing. The plugging
of test cells may be related to the  use of a surfactant solution.
By  hydrolyzing in water,  surfactants may block soil pores by
forming either floes or surfactant aggregates called micelles. In
addition, if the surfactant causes fine  soil particles to become
suspended in the flushing fluid, narrow passages between soil
particles could be blocked. If enough of these narrow passages
are blocked along a continuous front, a  "mat" is said to have
formed, and fluid flow is halted in that area [23] [7].

    Resource Conservation  Recovery Act (RCRA) Land  Dis-
posal Restrictions (LDRs) that require treatment of wastes to
best demonstrated  available technology (BOAT) levels prior to
land disposal may sometimes be determined to be applicable
or relevant and appropriate requirements (ARARs) for CERCLA
response actions. The soil-flushing 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
of the technology to meet required treatment levels is  depen-
dent upon  the specific waste constituents  and  the  waste
matrix.  In  cases where soil flushing does  not  meet these
levels,  it still may, in certain  situations, be selected for use at
the site if a treatability variance establishing alternative treat-
ment levels is obtained.  EPA has made the treatability vari-
ance process available  in order to ensure that LDRs  do not
unnecessarily  restrict the use of  alternative  and  innovative
                                      treatment technologies. Treatability variances may be justi-
                                      fied  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 Reme-
                                      dial Actions" (OSWER Directive 9347.3-06FS) [1 3], and Super-
                                      fund LDR Guide #6B, "Obtaining a Soil and Debris Treatability
                                      Variance for Removal Actions" (OSWER Directive 9347.3-07FS)
                                      [14],  Another approach could  be to  use other  treatment
                                      techniques in conjunction with soil flushing to obtain desired
                                      treatment levels.
                                      Technology Status

                                          In situ soil flushing is a developing technology that has had
                                      limited application  in the United  States.  In situ  soil flushing
                                      technology has  been selected as  one of the source control
                                      remedies at the 12 Superfund sites  listed in Table 3 [3].
                                      EPA Contact

                                          Technology-specific questions regarding soil flushing may
                                      be directed to:

                                          Michael Gruenfeld
                                          U.S. EPA, Releases Control Branch
                                          Risk Reduction Engineering Laboratory
                                          2890 Woodbndge Avenue, Building 10
                                          Edison, New Jersey 08837
                                          Telephone FTS 340-6625 or (908) 321-6625.
                                                          Table 3
                                         Superfund Sites Using In Situ Soil Flushing

    Byron Barrel & Drum

    Goose Farm

    Lipari Landfill

    Vineland Chemical

    Harvey-Knott Drum

    L.A. Clarke St Son

    Ninth Avenue Dump

    U.S. Aviex

    South Calvacale Street

    United Chrome Products

    Cross Brothers Pail

    Bog Creek Farm
Location (Region)

Genesee County, NY (2)

Plumsted Township, NJ (2)

Gloucester, N| (2)

Vineland, NJ (2)

	J DE(3)

Spotsylvania, VA (3)

Garry, IN (5)

Miles, Ml (5)

Houston, TX (6)

Corvallis, OR (10)

Pembroke, IL (5)

Howell Township, N| (2)
Primary Contaminants

VOCs (BTX, PCE, and TCE)

VOCs (Toluene, Ethylbenzene,
Dichloromethane, and TCE), SVOCs, and PAHs

VOCs (Benzene, Ethylbenzene, Dichlormethane,
and TCE), SVOCs, PAHs and Chlorinated ethers

Arsenic and VOCs (Dichloromethane)


Creosote, PAHs, and Benzene

VOCs (BTEX, TCE), PAHs, Phenols, Lead, I'CBs,
and Total Metals

VOCs (Carbon Tetrachloride, DCA,
Ethylbenzene, PCE, TCE, Toluene, TCA, Freon,
Xylene, and Chloroform)



VOCs (Benzene, PCE, TCE, Toluene, and
Xylenes) and PCBs

VOCs, Organics

Pre-design: finalizing workplan

In design: 30% design phase

Operational, summer '91


In design: re-evaluating alternative

In design

In design: pilot failed

Pre-design: re-evaluating alternatives

In design

Operational since 8/88

In desgn: developing workplan
                                                                                           In design: treatment plant completed,
                                                                                           dump and treat not installed
                                                                          Engineering Bulletin: In Situ Soil Flushing


    This bulletin was prepared for the U.S. Environmental Protec-
tion Agency, Office of Research  and Development (ORD),  Risk
Reduction Engineering Laboratory (RREL), Cincinnati, Ohio, by
Science Applications International Corporation (SAIC) under con-
tract No. 68-C8-0062.   Mr. Eugene Harris served as the  EPA
Technical Project Monitor.  Mr. Gary Baker  was SAIC's Work As-
signment Manager. This bulletin was  authored by Mr. Jim Rawe of
SAIC.  The author is especially grateful to Ms. Joyce Perdek of EPA,
RREL, who has contributed significantly by serving as a  technical
reviewer during the development  of this document.
    The following other Agency and contractor personnel have
contributed their time and comments by participating in the
expert review meeting and/or peer reviewing the document:
    Mr. Benjamin Blaney
    Ms. Sally Clement
    Mr. Clyde Dial
    Ms. Linda Fiedler
    Dr. David Wilson
Bruck, Hartman and Esposito
Vanderbilt University
    Ms. Tish Zimmerman   EPA-OSWER
1.   Handbook: In Situ Treatment of Hazardous Waste-
    Contaminated Soils.  EPA/540/2-90/002, U.S. Environ-
    mental Protection Agency, 1990.

2.   A Compendium of Technologies Used in the Treatment
    of Hazardous Wastes. EPA/625/8-87/014,  U.S.  Environ-
    mental Protection Agency, 1987.

 3.  Innovative Treatment Technologies:  Semi-Annual Status
    Report.  EPA/540/2-91/001, U.S. Environmental Protec-
    tion Agency, 1991.

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