EPA /500/SW-677
JANUARY 1978
                                               l
     .*».


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     An environmental protection publication (SW-677) in the solid waste
management series.   Mention of commercial  products does not constitute
endorsement by the U.S.  Government.   Editing and technical  content of this
report were the responsibilities of  the Systems Management Division of the
Office of Solid Waste.

     Single copies of this publication are available from Solid Waste
Information, U.S. Environmental Protection Agency, Cincinnati, Ohio, 45268.

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UPGRADING HAZARDOUS WASTE DISPOSAL SITES

           Remedial Approaches
   This report (SW-677) was written by
             Donald G. Farb
  U.S. ENVIRONMENTAL PROTECTION AGENCY

                  1978

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                         TABLE OF CONTENTS

                                                       Page

EXECUTIVE SUMMARY                                        1

INTRODUCTION                                             3

CONTROL AND DECONTAMINATION TECHNOLOGY                   5

     Infiltration Controls                               6

          Cover Materials                                6
          Grading and Contouring                         10
          In Situ Grouting                               11
          Other Infiltration Barriers                    17

     Excavate and Bury at a New Site                     17

     Leachate Plume Management                           21

     Leachate and Contaminated Groundwater Treatment     29

     Soil Manipulation                                   31

          Soil Flushing                                  31
          In Situ Chemical Detoxification                33
          Microbial Innoculations                        33

DECISION ANALYSIS                                        35

REFERENCES CITED                                         36

LIST OF TABLES

     1.   Cost for Various Sanitary Landfill
            Liner Materials                               8

     2.   Infiltration Barrier Costs                     16

LIST OF FIGURES

     1.   Cross Sectional View of Landfill
            with Layered Cover                            9

     2.   Potential Drainage Pattern for Area Fill       12

     3.   Potential Drainage Pattern for Trench Fill     13
                             111

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LIST OF FIGURES (cant.)                                 Page

     4.   Injected Soil Grout Curtain                    15

     5.   Effective Hazardous Waste Management -
            Disposal Phase                               19

     6.   Groundwater Pumping                            22

     7.   Effect of Differing Coefficients of
            Transmissibility upon the Shape, Depth
            and Extent of the Cone of Depression         24

     8.   Cost of Gravel-Packed Wells Finished in
            Sand and Gravel                              25

     9.   Cost of Shallow Sandstone, Limestone, or
            Dolomite Bedrock Vfells                       26

    10.   Cost of Tubular Vfells Finished in Sand
            and Gravel                                   27

    11.   Monthly Cost of Vfells and Pumping Systems      28

    12.   Well Point Dewatering System                   32
                                IV

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                        EXECUTIVE SUMMARY
     Groundwater contamination problems, resulting from the
indiscriminate disposal of potentially hazardous wastes, are seldom
so uncomplicated that one site restoration technique will adequately
serve to correct the contamination problem.  Such contamination is
typically the result of waste disposal practices which have led to
an accumulation of solids, liquids, sludges, discarded containers,
and miscellaneous debris.  Therefore, more than one remedial procedure
may be required to abate a groundwater contamination problem.  Such
procedures include:

     -  infiltration controls

             cover materials
             grading and contouring
             in situ grouting

     -  waste excavation and burial at a new site

     -  leachate plume management by groundwater pumping

     -  leachate and groundwater treatment

     -  soil manipulation

             soil flushing
             ^in situ chemical detoxification
             microbial innoculations

Of the above techniques, excavation represents the most reliable
abatement procedure, but also potentially the most expensive and most
objectionable from a citizen acceptance point of view.  Groundwater
pumping techniques may provide acceptable near-term control, however,
such techniques do not address the real problem, eliminating the source
of contamination.  Without effecting some control on the source of
contamination, groundwater pumping and treatment may be required for
an indefinite period.  Infiltration control techniques, especially
grouting and special cover materials, represent potential means of
achieving adequate control with minimum citizen opposition and at a
reasonable cost.  However, such approaches are currently viewed as
high-risk technologies due to the absence of case histories which
adequately demonstrate their technological and economical feasibility.
Finally, the pollution abatement potential of soil manipulation

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techniques has been successfully demonstrated.  However, the applica-
bility of these techniques is limited to specific contaminants that
are susceptible to the soil manipulation approach, such as chemical
spills.

     The final decision on which restoration approach(es)  should be
used should be based on an analysis on the following:

     -  type of contaminant and its characteristics

     -  levels of contamination

     -  areal extent of contamination

     -  quantity of contaminant at the source

     -  technical feasibility of potential restoration
          methods

     -  economic feasibility of potential restoration
          methods

     -  institutional and political constraints, such as
          public opposition

     -  tangible and intangible costs of taking no action
          and thus abandoning the resource

The science of cost/benefit analysis of groundwater resources is in
its infancy, especially the art of predicting intangible costs.  Since
economics and social/institutional issues are expected to play a major
role in the decision process, it is important that the development of
cost analysis techniques be adequate for its role in the decision process.

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                           INTRDDUCTIOSI
     An increasing number of groundwater contamination incidents,
resulting from the indiscriminate land disposal of potentially
hazardous wastes, is being brought to the attention of the U.S.
Environmental Protection Agency.  Such incidents are typically
revealed only after some public health or property damage has
occurred.  The number of incidents identified to date is considered
to be only the "tip of the iceberg," and many incidents remain to be
identified.^  Further support of this observation is found in the
Report to Congress on Waste Disposal Practices and their Effects
on Groundwater* which concluded that:

          Waste disposal practices have contaminated
          groundwater on a local basis in all parts of
          the nation and on a regional basis in a few
          heavily populated and industrialized areas.

          For every waste disposal facility documented
          as a source of groundwater contamination,
          there are thousands more which are sited,
          designed, and operated in a similar manner.
          Many of these potential sources are receiving
          hazardous wastes.

          Knowledge is especially lacking with regard
          to locations of potential sources of ground-
          water contamination and the severity of
          documented cases.  Monitoring of potential
          sources of groundwater contamination is
          almost nonexistent.2

These findings suggest that an unknown number of disposal sites are
currently contaminating, or will in the future contaminate, ground-
water resources and drinking water supplies.

     The origin of toxic chemical contamination of groundwater resources
may be a municipal landfill, a chemical spill, an exposed chemical
stockpile, or the direct discharge of a hazardous residual to land by
lagooning, land spreading, landfilling, and open dumping.  Regardless
of the origin, the events leading to the contamination of the ground-
water resources are the same; free liquids, usually water, leach readily
available waste constituents vertically through the unsaturated profile
     *0ffice of Solid Waste Management Programs and Office of Water
        Supply.  Washington, U.S. Environmental Protection Agency/
        1976.

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to the zone of saturation.  Movement in the water saturated zone is
horizontal with the rate of flow determined  by the gradient of the
aquifer and its permeability.  Although it has been assumed that
contaminants migrate laterally near the water table, recent research
indicates that the contaminants mav disperse at several levels in
the aquifer and migrate at levels. '

     Restoration procedures are defined as techniques employed to
restore the quality of the groundwater resource by isolating the
waste material from leaching liquids or by collecting and treating
leachate containing potentially hazardous constituents.  The following
will examine several remedial procedures to correct contaminating
disposal sites.

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               CONTROL AND DECONTAMINATION TECHNOLOGY
     The traditional public health approach to disease control,
breaking the vector-pathway-host transmission cycle, has a
parallel in the control of a contaminating waste disposal site.
In the case of a contaminating disposal site, the vector or carrier
is principally water, the pathway is a groundwater resource, and
people or other groundwater users (plants and animals) are the
hosts.  The agent in this case is not a biological agent, but
rather a toxic chemical leached from the waste.  The vector, water,
originates from a number of sources, including:

        precipitation
     .  groundwater intrusion
     .  moisture from the waste material
        direct disposal of liquid wastes
        decomposition of organic material

Once contaminated by leachates, the quality of the water supply may
be considered polluted if the contaminant(s) imparts odors, tastes,
or other physical or chemical characteristics that exceed a permissible
level as defined by drinking water standards, industrial processing
water requirements, or the requirements of other water users.  Remedial
measures, the set of pollution control measures taken to mitigate the
contamination problem, are typically applied only after public health
or property damage has been detected.

     In the traditional public health case, control measures are
applied at the weakest point in the disease transmission cycle.
Oftentimes, the weakest link is the disease vector.  Eliminating
the vector, water, in the case of a contaminating waste disposal
site does not represent a vulnerable point of attack, since
water is indigenous to the waste and soil, and is a byproduct of
the decomposition process.  For example, if buried refuse contains
less than 60 percent moisture, it will be difficult for micro-
organisms,-to perform the decomposition desired in a sanitary
landfill.

     However, controlling the vector's pathway, that is, stopping
infiltration into the disposal area and exfiltration from the disposal
area to the water resource, and/or attenuating the toxicity of the
chemical agent may be acceptable means of controlling the environmental
and public health impact of contaminating disposal sites.  Specific
means of achieving these ends include:

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     .   Infiltration controls

             liners and covers
             grading and contouring
             in situ grouting

     .   Excavation, treatment and burial of the waste
        at a new site

     .   Croundwater pumping and treatment

        Soil treatment

             contaminant flushing and treatment
             AD Hity detoxification
             rnicrobial innoculation

The ensuing discussion will examine the technological and economic
feasibility of each measure.  Finally, decision analysis will consider
the option of abandoning the contaminated water resource and providing
an alternate water supply.

Infiltration Controls

     Cover materials.  Current practice calls for the control of
infiltration by covering disposal areas with fine textured soils
and compacting the cover to minimize the percolation rate.
On-site soil is commonly used for cover material.  This approach
may lead to increased recharge by creating a source of artificial
recharge:

             Even with compaction, top cover material may
             have a higher permeability than undisturbed
             soil.

           .  A highly compacted subbase may lead to the
             buildup of a greater hydrostatic head in the
             deposition area; without relief, this head
             will contribute to the exfiltration process.

The cumulative effect of these factors is increased groundwater recharge
and a shallower zone of saturation, oftentimes raising the water table
into waste deposition area.  The artificial water table and exfiltration
will continue to exist as long as the top cover allows infiltration.

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     Capning the site with an impermeable material may provide adequate
infiltration control.  Synthetic materials such as polyvinyl chloride
(PVC) , polyethylene  (PE) , coated polypropylene, and chlorinated poly-
ethylene, such as Hypalon, have been recommended and proposed for capping
existing landfills.0' 7 '8 However, actual field experience with such a
capping material is very sparse.  New Castle County, Delaware, has capped
a ten-acre section of a county landfill with a coated polypropylene
(approximately 20 mils) .9 The material, prepared in rolls 10 feet by
1000 feet, was installed by slowly unrolling it across the face of the
landfill.  Successive sheets were overlapped to provide a shingled effect;
field splicing of adjacent sheets was not attempted.  Cost of the liner
material was less than $0.60 per square yard.  Cost estimates for other
liner materials are  indicated in Table 1.

     The major question yet to be answered is whether or not the liner
material will lose its physical integrity and break down before the
refuse is sufficiently decomposed and the threat of leachate contami-
nation has subsided.  Controls such as liners favor the development of
an anaerobic environment which also increases the waste decomposition
time.  Secondly, the integrity of the synthetic cap may be further
threatened by subsidence, which occurs after cap emplacement.  Such
subsidence may tear the liner or break the bond that splices together
adjacent sheets of liner material.  If additional subsidence threatens
the integrity of the liner, excavation and repair will be required to
avoid ponding and infiltration.  However, the potential for subsidence
is much less in an older landfill.  In humid regions, normal settlement
of a sanitary landfill seems to be exponential with time, with most of
the total settlement completed in three years. 1® Therefore, the use of
a synthetic liner to control infiltrate at an abandoned landfill site
may present less of a technological risk than at a recently completed
landfill.

     The subject of liner integrity and splice integrity under landfill
conditions is being examined by Haxo under contract to the EPA's Solid
and Hazardous Waste Research Division (SHWRD) , Cincinnati,
     A layered cover consisting of a layer of natural materials with very
low permeabilities, for example montmorillonite clay, followed by a layer
of a highly permeable material, such as sand, and finally a layer of
topsoil, has been proposed as a means of creating an infiltration barrier
and diversion system (figure 1) .12 Effective diversion of precipitation

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                                 Table 1


                       COST FOR VARIOUS SANITARY

                       LANDFILL LINER MATERIALS*
          Material
Asphalt sprayed on polypropylene fabric
   (100 mils)
Soil-bentonite (9.1 lbs/yd2)
Soil-bentonite (18.1 lbs/yd2)
Soil-cement with sealer coat (6 inches)
Installed cost"1"
  ($/sq yd)
Polyethylene (10 - 20* rnils§)
Polyvinyl chloride )10 - 30* mils)
Butyl rubber (31.3 - 62.5* mils)
Hypalon (20 - 45* mils)
Ethylene propylene diene monomer
(31.3 - 62.5* mils)
Chlorinated polyethylene (20 - 30* mils)
Paving asphalt with sealer coat (2 inches)
Paving asphalt with sealer coat (4 inches)
Hot sprayed asphalt (1 gallon/yd2)
0.90 -
1.17 -
3.25 -
2.88 -

2.43 -
2.43 -
1.20 -
2.35 -
1.50 -
1.44
2.16
4.00
3.06

3.42
3.24
1.70
3.25
2.00 (includ
                                                             earth cover)
1.26 - 1.87
    0.72
    1.17
    1.25
     * After:  Haxo, H.E., Jr.  Evaluation of liner materials.
U.S. EPA Research Contract 68-03-0230.  October 1973.
     + Cost does not include construction of subgrade nor the
cost of earth cover.  These can range from $0.10 to $0.50/yd2/ft
of depth.
     * Material costs are the same for this range of thickness.
     5 One mil = 0.001 inch.

Source:  Geswein, A.J.  Liners for land disposal sites - an assessment.
       U.S. Environmental Protection Publication SW-137.  Washington ,
       U.S. Government Printing Office, 1975. 66 p.

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                    FIGURE 1



CROSS SECTIONAL VIEW OF LANDFILL WITH LAYERED COVER

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may be achieved by providing sufficient sloping to avoid the buildup of a
hydrostatic head at the interface of the impermeable layer.  Precipitation
infiltrating the topsoil will be conducted vertically through the highly
permeable layer and, upon encountering the less permeable layer, move
laterally along the interface of the two layers, discharging at the toe
of the landfill into a surface runoff water collection system.

     In addition to improving the drainage, the approach also
increases the stability of the slope:

               If the slope under study is underlaid with
               a highly pervious gravel layer, the flow
               net consists of vertical flow lines and
               horizontal equipotentials.  Under this
               seepage condition, the energy of the free
               water in the soil is consumed harmlessly
               as it flows vertically downward to the
               gravel, and thence outward to the toe of
               the slope. •*

     As a final observation, in humid regions it has been noted that
leachate migration from a disposal site will still continue and contain
a greater concentration of contaminants, if infiltration is reduced
but not eliminated.-^ Therefore, it becomes important to completely
stop infiltration, not simply reduce it, to eliminate exfiltration.

     Grading and Contouring.  The most economical technique to
decrease infiltration is to grade, contour and vegetate the landfill
cover.  Grading and contouring work costs will vary widely depending
upon the nature of the material and task.  The objective of reshaping
and grading the site is to fill subsidence depressions and create
runoff patterns with shorter slopes which discharge to lined
(concrete, plastic or corrugated metal) swales and troughs.

     The relationship between rainfall and peak runoff may be
represented by the rational formula:  Q=CIA.   Where Q is the peak
discharge in cubic feet per second  (cfs), C is the runoff coefficient,
I is the rainfall intensity in inches per hour, and A is the drainage
area in acres.  The formula assumes that a maximum rate of runoff is
produced when rainfall is maintained for a period of time equal to
the time necessary to reach maximum flow.  The time lag between the
beginning of the rainfall and maximum runoff is defined as the time
of concentration  (tc).  The potential for head buildup and infiltration

may be reduced by decreasing t.,.  In other words, increasing  the
                              \*>
steepness of the slope and decreasing the slope length will reduce the
time of concentration.
                                10

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     An empirical formula for the time of concentration in hours
is:



          fcc = °'00013  ITOS5' where
          L  is the length of the basin area  (feet)
          S  is the average slope of the basin  -.^
             expressed as a dimensionless number

     Increasing the steepness of the slope will, however, increase
the erosion potential.  Therefore, slope erosivity becomes an upper
limit for determining the optimum slope.  The erosion potential may
be calculated by several formulae.  A modified Musgrave Equation has
been extensively used by the Soil Conservation Service, Department
of Agriculture:^6

                        „ 1.35    0.35
          E = 0.91KCP  -^    ~2Ti     where,

          E  is the sheet erosion in metric tons per year
          K  is the soil erodability factor
          C  is the cover factor
          R  is the rainfall factor
          S  is the percent slope
          L  is the length of slope in meters

Values for factors K, C, and R are available from the Soil
Conservation Service.

     Potential surface configurations to facilitate runoff are
illustrated in figures 2 and 3.  The objective in each case is
to shorten the length of slope, minimize erosion, maximize runoff
and provide for the collection of runoff.

     In situ grouting.  .In situ grouting is the process of injecting
low viscosity binding/cementing agents into a porous medium, such
as soil, to form an impervious barrier.  Several grouting agents
have been used to seal porous strata, including:  cement, epoxy
resins, liquid glass  (silicate grouts), poly isocyanate, acrylic
amide, chrome-lignin, and urea formaldehyde.

     The grouting concept has been used for a number of years by
the mining and oil industries to seal off highly permeable strata.
Pipeline companies have used grouting materials to effectively
                                11

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 Plan View with Contours
 Lined Drainage Troughs
'  Cross-Section along M'
        Figure 2
Potential  Drainage Pattern
       for Area Fill

      12

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                                        Fi gure  3

                        Potential Drainage Pattern  for Trench  Fill


                                Plan view with  contours
                                    lined troughs
Perimeter
Collection ^
Network
                                      iross
                                      13

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seal the walls of underground caverns used for liquified petroleum
gas storage.17 Grouting has been recommended by the EPA as a means
of sealing inactive and abandoned underground mines to eliminate
mine drainage.18 Underground grouting has been proposed to stem the
migration of leachates from radioactive waste burial sites.19

     In recent years methods have been developed to seal saturated
zones (below the water table) without impairing the grout's curing
process.  It has been found that grouting materials are stable over
extended periods of time and behave similar to concrete, becoming
harder and more stable with age, and are resistant to acids at pH 4.19i20

     Companies with long standing experience in underground grouting
report that grouts may be injected  (under pressure) to depths in excess
of 30 meters and seal strata 10 to 12 meters thick.2^'^^Grouting agent
viscosities range from 1.5 to 300 centipoises.  Short set time formu-
lations will achieve 85% of the desired strength in 30 minutes; total
strength is reached in 24 hours.  Gel times or set times may be shortened
to achieve stoppage of flowing water, or gel times may be extended up to
six hours to permit maximum induction (flow into the interstices of the
porous strata).

     Due to their transmissivity properties, unconsolidated strata
consisting of fine textured materials, clays and silts, are not as
effectively grouted as coarse textured strata, such as sand.  Soil
textures equal to or larger than a 200 mesh screen usually have
excellent grouting properties.  With finer textured soils, injection
points must be closer together to achieve an effective seal.

     Impervious grout curtains may be constructed around the perimeter
of a specific area, such as a contaminating disposal site, to retard
the flow of groundwater through the area  (figure 4).  In this instance,
injection points are drilled through the unsaturated overburden and
into the water-bearing strata.  Grouting materials are injected
into the saturated strata as the injection system is withdrawn.
Spacing of successive injection points would be determined by the
viscosity of the grouting material and the permeability of the
strata.  Such an approach may be entirely feasible for contaminating
disposal sites located in abandoned sand and gravel pits.  However,
the absence of actual case histories precludes an adequate assessment
of this technique.  Field work needs to be conducted to evaluate
in situ grouting"s potential to seal the bottom as well as the sides
of a contaminating disposal site.
                                   14

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                                Figure 4

                       Injected Soil Grout Curtain
                                                                 HOLES
                                                              IMPERVIOUS
                                                              (SROl/T CURTAIN
Source:  Wantland, Lloyd T.,  Halliburton Services,  Pittsburgh, Pa.
                                    15

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                      TABLE 2

            Infiltration Barrier Costs


                                        Total

   Slurry Trench  $6/sq ft            $370,000

   Imper-Wall  $4/sg ft               $240,000

   Grouting  $15/sq ft                $900,000

   Concrete Wall  $6.75/sq ft         $400,000
Source:  Atwell, J.S.  Identifying and correcting
    groundwater contamination at a disposal site.
    Presented at the Fourth National Congress on
    Waste Management Technology, Atlanta,
    November 1975. 32 p.
                      16

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     Material costs for grouting materials are indicated in Table 2.

     Other infiltration barriers.  In situations where the water
table exists at or near the surface, slurry trenches, emplaced steel
plates, an Imper-wal]^'technique may provide an adequate barrier.

     A slurry trench involves excavating a narrow trench and replacing
the excavated material with a bentonite slurry.  Excavated soil is
subsequently added as a cap on the trench.

     The use of steel plates involves the driving of successive
and overlapping steel plates to the desired depth; thus creating
a curtain to the lateral flow of water.

     Imper-wall is the trade name for a technique which involves
driving an I-beam to a desired depth and grouting the void space
created during extraction of the beam.  The beam has a steel pipe
attached to its full length.  As the beam is extracted, a cementitious
sealing material is continuously injected through the pipe.  A
continuous barrier is created by overlapping successive injection
points.

Excavate and Bury at a New Site

     The concept of excavation and burial involves the complete
removal of the source of contamination and transport to a new location
for final disposal.  The approach is applicable to chemical spill
sites as well as landfills.  Treatment of a liquid effluent and
possibly contaminated groundwater resources may also be required
as part of the problem's solution.  (Techniques for treating effluent
and groundwater resources will be discussed later on.)

     The decision to employ an excavation and burial method of site
restoration may not be based as much on the state-of-the-art as on
the:

     .  economic feasibility of an alternative restoration technique
     .  availability of a suitable disposal site (landfill, incinerator,
        etc.)  for excavated material
        size of the excavation problem
     .  public acceptance of the excavation process.

Other constraints, related to the cleanup of spilled material, as
identified by Lindsey, include:

     .  availability of transportation
        availability of cleanup funds
                                 17

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        suitability of temporary storage facilities
        citizen concern
     .  local, State, Federal regulations covering the transportation
        and disposal of spill materials.22

If these considerations do not represent overriding technical and
economic constraints, the approach may be the most reliable method of
eliminating a source of groundwater contamination.

     Open pit and strip mining techniques may be suitable for
excavation purposes.  Excavated material must be transported by
methods consistent with existing State and Federal regulations
governing the shipment of hazardous wastes.  The Department of
Transportation has proposed rules which state that the transportation
of hazardous material shall be conspicuously labeled. •*

     The burial of excavated hazardous residuals will require specific
attention to the location and design of the disposal site. Recommen-
dations for the engineered disposal of hazardous residuals may be found
in Landfill Disposal of Hazardous Wastes, Land Disposal, Technology
for Industrial Wastes, and work by Barr.  '6'25These recommendations
include (figure 5):

        waste pretreatment, where feasible
        disposal site infiltration and exfiltration barriers
        leachate collection and treatment systems
        saturated and unsaturated zone monitoring
        site registration and controlled access
     .  episode or contingency and maintenance plans.

Although not explicitly written for the purpose of disposing of
residuals excavated from contaminating disposal sites, their
recommendations are nonetheless applicable to such wastes.

     If the contamination consists of a small spill, and it is not
practical to dedicate a plot of land as an engineered disposal site,
it may be feasible to ship the spill cleanup materials to a licensed
hazardous waste management facility.  Information on such facilities
may be obtained from EPA Office of Solid Waste Management Programs,
Hazardous Waste Management Division publications or from State solid
waste management officials.  Disposal costs at such facilities range
from $1.00 to $30.00 per drum depending upon the nature of the waste.2^
Decisions to use such facilities should be made only after consulting
with the proper facility licensing authority.
                                  18

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                                                  19

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     In a 1970 case history involving 1.5 million cubic yards of     -9
buried refuse, excavation, hauling, and burial costs were as follows:

     excavating and loading      $0.50 per yd
     hauling                      1.95
     landfilling at new site       .50       -,        ^
       Total  (1970 dollars)      $2.95 per yd  (one yd  of compacted
                                         refuse is equal to approximately
                                         800 Ibs.)

     In a second site restoration case, projected excavation and
burial costs have been estimated to be:

        $6.75 per ton for removal and disposal at a site 10 miles
        from the existing landfill (figure includes $1.25 per ton
        for effluent and leachate controls)
     .  $12.00 to $16.00 per ton to remove and incinerate waste
        (range due to variations in incinerator design), includes
        credit for sale of recovered energy at a rate of $4.00 per
        ton of refuse.* 30

     A study conducted by the U.S. Army Materiel Command of a
contaminated site where potentially hazardous materials were disposed
of over a large area for many years, determined that complete excavation
and restoration of contaminated soil is technically and economically
infeasible.   In this situation, in situ soil treatment techniques may
offer the greatest potential for proper restoration.

     Efforts of Virginia officials to move Kepone, a pesticide,
contaminated waste and debris to another geographic area for disposal
met with stiff opposition from concerned citizens and public officials.
As a result, a specially designed landfill was constructed for part of
the waste near the contaminated site.  The site, with a capacity of
approximately 7300 cubic yards was lined with 30 mil reinforced PVC
     *
      The value of recovered energy is tied to the current value
of competing energy sources, coal, oil, and gas.  As the cost of
other energy sources increases, the value of energy recovered
from refuse also increases.
                                 20

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liner  (approxinrt ly 200 feet by 150 feet) and capped with 15 mil
non-reinforeed PVC.  Cost of the bottom liner was estimated to be
approximately $10,000  (approximately $3.00 per yard).  Site design
also included a network of perforated corrugated PVC pipes (4")
under the bottom liner to facilitate the detection of liner failure
and leachate movement.  Clean fill was placed on the bottom liner
to protect it from rupture during the filling operation.  The emplaced
wastes were covered with a 4-foot layer of soil to protect the PVC
cap.  Finally, the PVC cap was covered by 4 feet of soil, graded,
and seeded.  Location of the site and its contents have been
registered with local officials.

     The cost of additional cleanup work involving the removal,
treatment (incineration)  and replacement of soil (1000 foot radius
at a depth of one inch) around the Kepone contamination site has been
estimated to be $1.5 million.32

     In the final analysis, the decision to excavate and ship the
source of contamination to a new site may be largely determined by
the economics and by citizen acceptance of the proposed cleanup plan.

Leachate Plume Management

     When moisture from infiltration and other sources saturates
the soil and refuse beyond field capacity, accumulated liquids will
flow under the influence of gravity and hydrostatic pressure in the
path of least resistance.  Exfiltrate or leachate is the solution
of leached waste constituents that migrates from the disposal site.
The gradual escape (exfiltration) of leachate may occur as surface
seepage at the toe of the disposal site, if the subcase of the
burial site is highly impermeable.  Or, leachate may move vertically
through the unsaturated profile and enter the groundwater regime.

     Surface seepage of leachates may be handled by installing lined
collection ditches and basins at the discharae points and treating
the collected effluent.  Treatment methods for leachate will be
discussed later in this section.

     Exfiltration of leachate into water table aquifers represents
a more difficult restoration problem.  In this situation, continuous
groundwater pumping may be required until the source of contamination
is controlled and groundwater quality restored (figure 6).  Factors
that affect such groundwater cleanup efforts include:

     1.  Aquifer permeability (the quantity of water that will flow
         through a cross sectional area in unit time under a hydraulic
         gradient of unity). - A well in an aquifer with-a low
                                 21

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     Figure 6
Groundwater Pumping
                                        CO
        22

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     1.  Aquifer permeability  (the quantity of water that will flow
         through a cross sectional area in unit time under a hydraulic
         gradient of unity). - A well in an aquifer with a low
         permeability will have a cone of depression with a smaller
         radius of influence than a similar well in a more permeable
         aquifer (figure 7).  Therefore, control of leachate movement
         in aquifers of low permeability will require more wells
         and closer spacing to achieve the desired overlapping
         cones of depression.
     2.  Type of contaminant - Contaminants that tend to migrate
         at or near the bottom of the aquifer will require higher
         Pumping rates and deeper wells than contaminants that tend
         to migrate near the water table.
     3.  Attenuative capabilities of the saturated and unsaturated
         profiles - Sorption properties of the saturated and
         unsaturated strata as well as the dispersion potential
         (i.e., how rapidly leachates are diluted by groundwater
         flow) will, first of all, determine if and when down gradient
         water supplies will become contaminated.  Secondly, attenuative
         properties will partially dictate where wells should be
         installed in order to achieve optimum plume control at minimum
         costs.  For example, arsenic ions and chlorinated hydrocarbons
         tend to be held by soil particles, whereas chloride and
         fluoride ions readily migrate.
     4.  Source of contamination - Without affecting some control on
         the source of contamination, leachates will continue to be
         a problem.  The source of contamination may be controlled by
         excavating the waste material and disposing of it in a non-
         leaching environment, or capping the disposal area, thereby
         creating a non-leaching environment on-site.  (The afore-
         mentioned approaches were discussed in detail earlier.)

     Groundwater pumping has been applied as a control technique
in several cases because it has been found to be the most economical
procedure.  Representative well and pump costs for Illinois wells
(1964-1966), as reported by Gibb and Sanderson and Gibb, are presented
in figures 8 - 11.33,34

     Without controls to limit further infiltration, leaching and
groundwater contamination will continue until the source of
contamination is depleted, and dispersion re-establishes groundwater
quality.  With infiltration controls or excavation of the waste,
groundwater quality should tend toward recovery as pumping continues.
It is feasible to estimate the recovery period for a contaminated
aquifer.  The estimate requires knowledge of the infiltration rate,
                                  23

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                           Figure 7
   a
   TJ
     10-
    20-
            (A)       hRodius-
18,000 ft-
  Transmissibility • 10,000 gpd/ft
                                            Radius • 40,000 ft •
                       s-2.5ft-
                                   Transmissibility - 100,000 gpd/ft
    20-

           EFFECT OF DIFFERING COEFFICIENTS OF TRANSMISSIBILITY UPON
           THE SHAPE, DEPTH AND EXTENT OF THE CONE OF DEPRESSION,
           PUMPING RATE AND OTHER FACTORS BEING THE SAME IN BOTH
           CASES.
t the  coefficient of transmissibility  (T)  is a measure  of
    permeability   (T = permeability X  aquifer thickness)
Source:   Ulric, G.P.,  and R.P.  Singer.   Water well manual.
            Berkeley, Premier  Press, 1973"156  p.
                                24

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                              Figure  8
     ICO

      80


      6C
  "i	r ~~i  r ", • i" i
     '../"•Fit COST ES'lllATt

Ass-jr, _-t 1C".
  Vt I i % --h =- I 10 fVit
  Des r> . > • t ' d - 20C gc".
  Wc'l j. j-Ktcr - 8  ic!-t:<; ' nblc I)
  Gra-f i  ,Mck j-inulbs = (• '-,c •.-•. -.hick
  Bore },")! ; d'aTieter = 20 inc c^
                                          	30' CO::FISS-.CE LIMITS
                       6rJ   80  100        700
                            DEPTH CF W'LL fJ) lil FEET
                                                             1000
Soxorce:   Gibb, J.P.,  and E.W.  Sanderson.   Cost of municipal
             and industrial  wells in  Illinois,  1964 -  1966.
             Urbana,  Illinois State Water Survey, Circular  98,
             1969.   22  p.
                                   25

-------
                        Figure 9
   30
   20
   10
   8.0
   6.0
   4.0
 -7 3.0
 £ 2-0
1 1 1 1 1
SAMPLE COS1 ESTIMATE
Assumpt ions :
_ Dolomi tc Wei 1
Well depth - 290 feet
Desired yield - 500 gpm
Well diameter •= 10 inches
Estimated We) 1 Cost:
Expected range $3300 - SA3
- "Best fit" $3700












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          60   80  100
  200       '.00    600  800 1000      2000
DEPTH OF WELL (d) III FEET
             Coat of ohallou uandntane, limeatona, or dolomite bedfoak ualle
Source:  Gibb, J.P., and E.W.  Sanderson.  Cost of municipal
             and industrial wells in Illinois,  1964 - 1966.
             Urbana,  Illinois State Water Survey, Circular 98,
             1969.   22 p.
                             26

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                            Figure 10
100
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S
        20
                 1)0
                      60  80  100       200

                         DEPTH OF WELL (d) IN FEET
                                              WO    600   1000
                   Coat of tubular i-'elle finished in sand and gravel
Source:   Gibb, J.P., and E.W.  Sanderson.   Cost of municipal
            and industrial wells in Illinois, 1964 - 1966.
            Urbana,  Illinois  State Water Survey,  Circular 98,
            1969.   22 p.
                               27

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                     Figure 11

    Monthly cost of wells and pimping systems
               EQUIVALENT MONTHLY COST OF WELL ANO PUMPING SYSTEM IN DOLLARS

                                            s
Source:   Gihb, J.P.  Cost of domestic wells and water
            treatment in Illinois.   Groundwater, 9(5):40-49,
            Sept. - Oct.  1971.
                          28

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measurements of groundwater levels, permeability, runoff, and
evaporation.15 in addition, an unknown contamination potential
may remain  in the landfill or disposal area, and will continue
to contribute leachate migration if a hydrostatic head remains
in the disposal area.

Leachate and Contaminated Groundwater Treatment

     Leachate treatment or groundwater treatment involves upgrading
the quality of the exfiltrate to a point where it may be discharged
without further damage to the environment.

     Recycling leachate back to the disposal site by well-point
injection or spray irrigation does not constitute a recommendable
treatment approach.  Major weaknesses with this approach include:

        Many hazardous constituents of industrial waste leachates
        (e.g., heavy metals) do not degrade and will remain in
        solution unless steps are taken to precipitate them out
     .  The acidic properties of such leachate will accelerate the
        release of additional hazardous constituents
     .  Without exfiltration controls, recycled leachate will
        contribute to the hydrostatic head in the disposal area and
        provide a continuing threat to the quality of underlying
        water resources.

Due to the high inorganic chemical and stable organic chemical
nature of industrial waste leachate, tertiary wastewater treatment
and water purification techniques are proving to be successful
leachate treatment techniques.  Studies conducted by the Army Materiel
Command indicate that reverse osmosis and carbon coagulation are the
most feasible means of removing pesticide and nerve agent by-products
from contaminated groundwater.31

     Liskowitz _et al., studied the leachate treatment potential of
several readily available sorbent materials (activated alumina,
activated carbon, fly ash, bottom ash, illite, kaolinite, zeolite,
Cullite, and vermiculite).35 Leachates from calcium fluoride sludge,
metal finishing sludge, and petroleum sludge are passed through columns
of sorbent materials to determine the attenuative characteristics
of each sorbent.  Although no single sorbent material was found to
be completely effective in removing all toxic ions from the leachates,
two or three different sorbent materials could be combined to reduce
leachate constituents to acceptable levels.  Activated alumina,
illite, and activated carbon proved to have the most versatile sorbent
properties.  Work is continuing in an effort to develop a leachate/
sorbent matrix for a greater number of industrial wastes.
                                 29

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be completely effective in removing all toxic ions from the leachates,
two or three different sorbent materials could be combined to reduce
leachate constituents to acceptable levels.  Activated alumina,
illite, and activated carbon proved to have the most versatile sorbent
properties.  Work is continuing in an effort to develop a leachate/
sorbent matrix for a greater number of industrial wastes.

     Packaged physical-chemical waste water treatment units are now
available for treating sanitary landfill leachate.  Such leachate
treatment systems include the following features:

     -  equalization - aeration
     -  chemical addition with flash mixing
     -  controlled flocculation
     -  clarification by sedimentation
     -  dissolved organic removal by carbon adsorption
     -  pressure filtration with programmed backflushing
     -  breakpoint chlorination
     -  pH adjustment.^^

Models with throughput capacities up to 300,000 gallons per day (gpd)
are available.  Operating costs for a 100,000 gpd unit are approximately
?0.20 per 1000 gallons.

     Leachate treatment units have been installed at landfills in
New Jersey and Pennsylvania, and a pharmaceutical manufacturing plant
in Indiana. ' Such units have shown better performance characteristics
if additional aeration is provided prior to the treatment routine.
High ammonia  (NH^) levels also tend to reduce the treatment efficiencies
of such units.  Jorgensen found that clinoptilolite, a silicate material
similar to zeolite, had good ion exchange potential for removing NH^
from wastewater with high concentrations of competitive calcium and
sodium ions. ° Extended aeration and steam stripping may also facilitate
the removal of NH^.

     Sludges and other residuals generated from the treatment of
leachate should receive treatment and disposal by methods which
assure that their toxic constituents will not resolubilize and
constitute an environmental threat.  If the potential for resolu-
bilization exists, ultimate land disposal should follow the recommen-
dations for the secure disposal of hazardous industrial wastes as
described earlier.24,6,25
                                 30

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     Incineration of the resultant sludges may be feasible if the
wastes are amenable to thermal destruction or recovery.  A review
of the operating characteristics and hazardous waste destruction
potential for 11 incinerator designs has been published by the
U.S. EPA Office of Solid Waste Management Programs.39

Soil Manipulation

     Site restoration may be achieved by:  flushing the contaminant
from the soil, _in situ contaminant detoxification, or microbial
degradation of the contaminant.  These approaches are often practical,
if the depth of contamination is fairly shallow and the areal extent
of contamination is relatively small.  Therefore, chemical spills
and contamination resulting from sludge dumping or land spreading
are likely sources of contaminations for these restoration techniques.

     Soil flushing.  Soil flushing is the process of flooding the
area of contamination and collecting the seepage with a series of
shallow well points (figure 12).  This elutriation or washing
process is most successful when the contaminant(s) is readily soluble
in water.  Slightly acidic solutions may be used to manipulate the
soil pH, and thereby accelerate the flushing of certain contaminants,
such as metal hydroxides.

     Elutriate collected by pumping the shallow well points should
be properly treated if it does not meet existing discharge standards.
Depending upon the nature of the contaminant, precipitation, adsorption,
and/or chemical oxidation may be viable treatment techniques.
Packaged wastewater treatment and water purification units offer
several physical and chemical treatment modalities necessary to
successfully remove many chemical contaminants.  Treated and clarified
elutriate may be recycled in the flushing process.  Packaged treatment
units for treating sanitary landfill leachate may be applicable.36

     Precipitation with ferric sulfate (Fe2(SC>4)3) and lime  (CaCC>3)
has proven to be effective in removing arsenic flushed from contaminated
soil.l^'^As noted earlier, several readily available sorbent materials,
singularly or in combination, may provide satisfactory contaminant removal.35

     Toxic and/or readily soluble hazardous precipitates, and
contaminated sorbents should be disposed of in a manner that will
avoid the recurrence of similar contamination problems (see: "Excavate
and Bury at a New Site").
                                 31

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                             Figure 12
         Saturated  sand .
           Sub-soil
           WELL-POINT DEWATERING SYSTEM.
Source:  Ulric,  G.P., and R.P.  Singer.  Water well manual.
            Berkeley, Premier Press, 1973.   156 p.
                                  32

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     In situ chemical detoxification.  In situ chemical detoxification
is the process of flooding or injecting the contaminated area with
a medium that will detoxify or otherwise render the contaminant
harmless.  The approach is restricted to those contaminants that
are readily degradable, have non-toxic breakdown products, and/or
are convertible to insoluble precipitates.  Heterogeneous mixtures
of chemical wastes represent a more difficult problem because of the
inhibitory influence of other constituents.  For example, sodium
hypochlorite (NaOCl), at 2500 parts per million (ppm) available Cl~,
has been successfully used to detoxify cyanide contamination resulting
from the indiscriminate dumping of industrial wastes (Sara, 1976).
Metal complexed cyanides were not as susceptible to chlorination.

     Further discussions on the feasibility of chemically detoxifying
specific hazardous materials may be found in "Recommended Methods
of Reduction, Neutralization, Recovery, or Disposal of Hazardous
Wastes, Oil and Hazardous Materials Technical Assistance Data System -
OHM TADS and the "Chemical Hazard Response Information System (CHRIS).42'43'44

     Microbial innoculations.  The concept of using microorganisms
to achieve site restoration through biodegradation may be applicable
if the waste material is an organic compound.  The ability of bacteria,
fungi, and other microorganisms to degrade organics has been recognized
for many years.  Weisberg, et_al., examined the hazardous waste
disposal practices of the petroleum refining industry and found that
landspreading of refinery wastes has been practiced successfully
for many years.

     Almost any hydrocarbon can be attacked by microorganisms,
however straight chain hydrocarbons are more susceptible to microbial
decomposition than branched or cyclic compounds.^Susceptibility also
decreases as viscosity and molecular weight increase.   Many microorganisms
are able to form special enzyme systems that are capable of breaking down
certain enzyme-inducing hydrocarbons, such as pesticides.48

     Genera most capable of metabolizing hydrocarbons are largely
aerobic; Pseudomonas, Achromobacter, and Alcaligenes are most
frequently found in petroleum contaminated soil (Ellis and Adams,
1961).  Facultative anaerobes associated with hydrocarbon
decomposition include species from the genera Aerobacillus and Bacillus.

     Schwendenger seeded oil contaminated soil with Cellulomonas sp.
and achieved improved hydrocarbon decomposition rates.    Practices
such as aerating, fertilizing, and manuring have been found to be
                                 33

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     Schwendenger seeded oil contaminated soil with Cellulomonas sp.
and achieved improved hydrocarbon decomposition rates.46 Practices
such as aerating, fertilizing, and manuring have been found to be
beneficial to the decomposition process.  For sites contaminated
with oily wastes, Schwendenger recommends in situ biodegradation;
to remove the contaminated soil merely defers the ultimate problem
of proper disposal.

     Finally, it should be noted that microbial decomposition pay
be more time consuming than other restoration approaches.  Therefore,
if a real and immediate public health or other environmental danger
exists, physical and/or chemical restoration techniques will provide
more timely results.
                                34

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                        DECISION ANALYSIS
     In the final analysis, contamination problems are seldom so
simple that one decontamination technique will adeauately restore
the contaminated site.  Contamination problems are typically the
result of disposal practices which have led to an accumulation of
the waste material, discarded containers, miscellaneous debris, not
to mention contaminated soil and groundwater.  Therefore, proper
management of these contaminants and restoration of the environment
may reauire the use of more than one decontamination procedure.
For example, groundwater pumping and treatment may be required in
addition to _in situ treatment or excavation and burial.

     Specifically, the restoration decision should consider the
following factors:

     1.  type of contaminant and its characteristics (organic,
         inorganic, toxicity, solubility, mobility, etc.)
     2.  level of contamination (soil and/or groundwater) and
         concentration
     3.  areal extent of contamination
     4.  quantity of contaminant at the source
     5.  technical feasibility of treatment and restoration methods
         for each contaminant
     6.  economic feasibility of treatment and restoration methods
     7.  institutional and political constraints, such as public
         acceptance of the selected restoration approach
     8.  cost of abandoning the resource and taking no action to
         restore the site.

'The cost of abandoning the contaminated land and groundwater resources
should consider both tangible and intangible costs.  Shuster examined
the tangible costs (corrective measures, avoidance, litigation, and
the provision of an alternative water supply) associated with six
cases of water well contamination and found that costs ranged  from
$7,000 to $2,000,000.49 jn four other cases, the tangible costs
associated with ungradino a contaminated drinking water supply or
providing an alternative water supply, ranged from $50,000 to
$300,000.50

     Intangible costs (convenience, esthetics, social welfare, and
psychic costs) are not easily estimated.  Predictino intangible
costs for land and groundwater resources is a relatively new science;
reliable indices for such costs need further development.
                                 35

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                       REFERENCES CITED
 1.   Lazar,  Emery.   Damage incidents from improper  land  disposal.
        Proceedings;  the National  Conference on Management and
        Disposal  of Residues from  the Treatment of  Industrial
        Wastewaters,  Washington, D.C., Feb.  3-5,  1975.   Rockville,  MS.,
        Information Transfer,  Inc.  15 p.

 2.   Office  of Solid Waste Management Programs and  Office of Water
        Supply.   The report to Congress - waste disposal practices
        and  their effects on groundwater. Washington, U.S.  Environmental
        Protection Agency, 1976.   (In preparation.)

 3.   Personal communication.  Hans Mooij, Environment Canada,
        to D.G.  Farb, Office of Solid Waste  Management Programs,
        Dec.  22,  1975.

 4.   Personal communication.  W.H. Walker, Geraghty and  Miller,  Inc.,
        to D.G.  Farb, Office of Solid Waste  Management Programs,
        Sept. 1975.

 5.   McKinney, R.E.   Microbiology  for sanitary engineers.   New York,
        McGraw-Hill Book Co.,  Inc., 1962. 293 p.

 6.   Farb, D.G.   Land disposal of  industrial wastes.  Proceedings;
        the  National Conference on Management and Disposal of
        Residues from the Treatment of Industrial Wastewaters,
        Washington,  D.C., Feb. 3-5, 1975. Rockville, Md., Information
        Transfer, Inc.   19 p.

 7.   Personal communication.  David Miller,  Geraghty and Miller,  Inc.,
         to  D.G.  Farb,  Office of Solid Waste Management  Programs,
         Apr. 6,  1976.

 8.   Wehran  Engineering Corp.   Engineering report - Scientific,  Inc.
        chemical waste processing  facility and Kin-Buc sanitary
        landfill. Middleton, New York, 1975. 51 p.

 9.   Personal communication.  W.L. Garrett,  E.I.  duPont  Co., Inc.,
        to D.G.  Farb, Office of Solid Waste  Management Programs,
        July 1975.

10.   Salvato, J.A., W.G. Wilkie, and B.E. Mead.  Sanitary landfill
        leaching prevention and control.  Water Pollution Control
        Federation Journal 43(10): 2084-2100, Oct.  1971.
                                  36

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11.  Haxc, H.E., Jr.  Evaluation of selected liners when exposed
        to hazardous wastes.  Presented at the Hazardous Waste
        Research Symposium on Residuals Management by Land Disposal,
        Tucson, Feb. 2-4, 1976. 12 p.

12.  Personal communication.  Paul Rhue, Geraghty and Miller, Inc.,
        to D.G. Farb, Office of Solid Waste Management Programs,
        Apr. 6, 1976.

13.  Cedergren, H.R.  Seepage, drainage, and flow nets.  New York,
        John Wiley and Sons, Inc., 1967. 489 p.

14.  Personal communication.  Dale Kosher, Office of Solid Waste
        Management Programs, to D.G. Farb, Office of Solid Waste
        Management Programs, Apr. 7, 1976.

15.  Chow, V.  Handbook of applied hydrology - a compendium of water
        resources technology.  New York, McGraw-Hill Book Co.,
        1964. 1418 p.

16.  Office of Air and Water Programs.  Methods for identifying and
        evaluating the nature and extent of nonpoint sources of
        pollutants.  U.S. Environmental Protection Publication
        430/9-73-014.  Washington, U.S. Government Printing Office,
        1973, 261 p.

17.  Lenahan, Torn.  There is a place for grouting in underground
        storage caverns.  Bulletin of the Association of Engineering
        Geologists, 10(2): 137-144, 1973.

18.  Office of Water and Hazardous Materials.  Inactive and abandoned
        underground mines water pollution prevention and control.
        U.S. Environmental Protection Publication 440/9-75-007.
        Washington, U.S. Government Printing Office, 1975.   338 p.

19.  Personal communication.  B.G. Taylor, Applied Nucleonics Company,
        to D.A. Rodgers, Contracts Management Division, Jan. 19, 1976.

20.  Personal communication.  Robert Jensen, Air Frame Manufacturing
        and Supply Co., North Hollywood, Calif., to Robert Landreth,
        Solid and Hazardous Waste Research Division, Feb. 23, 1976.

21.  Personal communication.  L.T. Wantland, Halliburton Services,
        to D.G. Farb, Office of Solid Haste Management Programs,
        Jan. 1976.
                                37

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22.  Lindsey, A.W.   Ultimate disposal of spilled hazardous materials.
        Chemical Engineering  82(23): 107-114,  Oct.  27,  1975.

23.  Metcalf, J.C.   Hazardous materials labelling and placarding
        systems - state-of-the-art.   Washington, D.C., Office  of
        Solid Waste Management Programs, 1975.   (Unpublished report.)

24.  Fields, T., Jr., and A.W. Lindsey.  Landfill disposal of  hazardous
        wastes:  a review of literature and known approaches.
        U.S. Environmental Protection Publication SW-165.   Washington,
        U.S. Government Printing Office, 1975.  36 n.

25.  Barr Engineering.  Chemical waste land disposal  facility
        demonstration grant application - Minnesota Pollution  Control
        Agency.  U.S. Environmental  Protection Publication SW-87d,
        1975.  178 p.  (Available through National Technical
        Information System [NTIS] as PB~ 249 77).

26.  Farb, D.G., and S.W. Ward.  Information about hazardous waste
        management facilities.  U.S. Environmental Protection
        Publication SW-145.  Washington, U.S.  Government Printing
        Office, 1975. 130 p.

27.  Leshendok, T.V.  Hazardous waste management facilities in the
        United States.  U.S. Environmental Protection Publication
        SW-146.2.  Washington, U.S.  Government Printing Office, 1976.
        61 p.

28.  Foster D. Snell, Inc.  Potential for capacity creation in the
        hazardous waste management service industry.   U.S. Environmental
        Protection Agency, 1977.  (In preparation; to be distributed by
        National Technical Information Service, Springfield, Va.)

29.  Personal communication.  G.B. Seaborn, Minnesota Pollution
        Control Agency, to D.G. Farb, Office of Solid Waste Management
        Programs, Feb. 17, 1976.

30.  Niessen, Walter.  Preliminary feasibility study - leachate
        control strategies for Llangollen Landfill,  New Castle County,
        Delaware.  West Chester, Pa., Roy F. Weston,  Inc., 1974.
        60 p.

31.  Bass, S.H., Jr.  Review and command assessment of the installation
        restoration program.  U.S. Army Materiel Command.   Edgewood
        Arsenal, Maryland, 1976. 129 p.
                                 38

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32.  Memorandum.  Wilson Talley, Office of Research and Development,
        to the Assistant Administrators, U.S. Environmental Protection
        Agency, March 29, 1976.

33.  Gibb, J.P., and E.W. Sanderson.  Cost of municipal and industrial
        wells in Illinois, 1964-1966.  Urbana, Illinois State Water
        Survey, Circular 98, 1969.  22 p.

34.  Gibb, J.P.  Cost of domestic wells and water treatment in
        Illinois.  Groundwater, 9(5): 40-49, Sep.-Oct. 1971.

35.  Liskowitz, J.W., et al.  Capabilities of selected sorbents for
        removal of leachate contaminants from industrial sludges.
        Presented at the Hazardous Waste Research Symposium on
        Residuals Management by Land Disposal, Tucson, Feb. 2-4,  1976.
        20 p.

36.  Personal communication.  C.E.  Janson, Met Pro Systems, Inc.,
        to D.G. Farb, Office of Solid Waste Management Programs,
        Jan. 13, 1976.

37.  Personal communication.  Bernard Stoll, Office of Solid Waste
        Management Programs, to D.G. Farb, Office of Solid Waste
        Management Programs, Feb.,  1976.

38.  Jorgensen, S.E.  Recovery of ammonia from industrial wastewater.
        Water Research  9(12): 1187-1191, Dec. 1975.

39.  Scurlock, A.C., A.W. Lindsey,  Timothy Fields, Jr., and D.R.  Huber.
        Incineration in hazardous waste management.  U.S. Environmental
        Protection Publication SW-141.  Washington, U.S. Government
        Printing Office, 1975.  104 p.

40.  Personal communication.  Thomas lezzi, Rohm and Haas, to D.G.  Farb,
        Office of Solid Waste Management Programs, March 17, 1976.

41.  Personal communication.  Martin Sara, Danes and Moore, to
        D.G. Farb, Office of Solid Waste Management Programs,
        Feb. 1976.

42.  Ottinger, R.S., et al. [TRW Systems Group]   Recommended methods
        of reduction, neutralization, recovery or disposal of
        hazardous wastes, vols. I - XVI.  U.S. Environmental Protection
        Publication 670/2-73-053.  Washington, U.S. Government
        Printing Office, Aug.  1973.  (Available through National
        Technical Information Service, Springfield, Va.)
                                 39

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43.  Office of Oil and Hazardous Materials.  Oil and hazardous
        materials assistance data system - OHMTADS.  U.S. Environmental
        Protection Agency.  Washington, U.S. Government Printing
        Office, 1974.  9 p.

44.  U.S. Coast Guard.  Chemical hazards response information system.
        Department of Transportation Publication CG-446-2.  Washington,
        U.S. Government Printing Office, 1974.  2 volumes.

45.  Jacobs Engineering Co.  Assessment of industrial hazardous waste
        practices, petroleum refining industry.  U.S. Environmental
        Protection Agency, 1977.  (In preparation; to be distributed
        by National Technical Information Service, Springfield, Va.)

46.  Schwendinger, R.B.  Reclamation of soil contaminated with
        oil.  Journal of the Institute of Petroleum  54(535): 182-197,
        July 1968.

47.  Ellis, Roscoe, Jr., and Russell Adams, Jr.  Contaminating
        soils by petroleum hydrocarbons.  Advances in Agronomy,
        13: 197-216, 1961.

48.  Rogers, C.J., and R.E. Landreth.  Degradation mechanisms:
        controlling the bioaccumulation of hazardous materials.
        U.S. Environmental Protection Publication 670/2-75-005.
        Washington, U.S. Government Printing Office, 1975.  14 p.

49.  Shuster, K.A.  Gas and leachate generation and control in
        landfills.  Presented at the University of Wisconsin Continuing
        Engineering Short Course, Madison, March 29-31, 1976.

50.  Personal communication.  A.B. Giles, Office of Solid Waste
        Management Programs, to D.G. Farb, Office of Solid Waste
        Management Programs, March 1976.
                                                               ya!512
                                                               SW-677
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