United States
Environmental Protection
Agency
Water Engineering Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-168 Dec. 1985
4>EPA Project Summary
Field Studies of Liner Installation
Methods at Landfills and
Surface Impoundments
David W. Shultz
Procedures were investigated for
subgrade preparation and liner place-
ment during the construction of lined
surface impoundments and landfills.
Lining materials studied include ad-
mixes, soils and clays, sprayed on mem-
branes, and polymeric membranes.
Objectives of the study were to (1)
identify liner installation practices
recommended by industry, (2) identify
methods and equipment used for
subgrade preparation and liner installa-
tion, and (3) compare industry-recom-
mended procedures with actual
practice. The study also identifies spe-
cial problems that can be avoided by
following proper placement procedures.
Polymeric membrane liners are empha-
sized because most liners currently
being installed are of this type.
This Project Summary was developed
by EPA's Water Engineering Research
Laboratory, Cincinnati, OH, to an-
nounce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The use of surface impoundments and
landfills has long been a cost-effective
method for industrial and municipal
agencies to store, treat, and dispose of
unwanted materials. But recent studies
show that the use of such facilities can
result in subsurface migration of
hazardous materials into groundwater.
The Resource Conservation and Recovery
Act (RCRA) of 1976 and proposed U.S.
Environmental Protection Agency (EPA)
regulations require that the subsurface
migration of contaminants be prevented
at facilities where hazardous materials
are stored. Natural and manmade liners
are currently being used to prevent or
minimize seepage of polluting fluids from
surface impoundments and landfills.
Numerous types of liners exist. Liners
most often used in disposal facilities are
classified by type of construction,
structure, materials, and method of
application. These liners prevent or
minimize fluid seepage in two ways:
Either they physically impede the flow of
fluid, or they absorb or retain contami-
nating chemicals from the fluid. Soils
generally absorb certain contaminants
and also impede the flow of fluid because
of low permeability. Manmade liners
function more as a barrier to fluid flow as
a result of very low permeability.
This study was initiated in 1979 to
investigate liner placement procedures
and subgrade preparation during the
construction of lined fluid surface
impoundments and landfills for fluids. A
variety of liner materials were investi-
gated, including admixes, soils and clays,
sprayed on membranes, soil sealants,
and polymeric membranes. The objec-
tives of the study were as follows:
1. To identify liner installation
practices suggested by industry,
2. To identify the methods and
equipment used for subgrade prep-
aration whenever possible,
3. To identify methods and materials
used to install liners,
4. To compare suggested procedures
with actual practice, and
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5. To identify special problems that can
be avoided by following proper
placement procedures.
Procedures
Identifying Industry-Suggested
Practices
Personal contacts with industry repre-
sentatives and review of current industry
literature were used to identify liner
installation procedures and desirable
subgrade characteristics suggested by
industry Suggested practices were
solicited for the following.
Installation procedures.
Site storage of material
Equippment used to place liner
Technique of positioning liner
Material overlap
Field seaming technique
Adhesives used
Tools required
Weather limitations
Crew size and experience
Sealing around penetrations
Anchoring system
Soil cover details
Quality control program
Application rates for soil sealants
Clay composition
Support fabric used
Subgrade characteristics
Surface texture
Compaction required
Herbicide treatment
Surface geometry
Surface composition
Selecting Sites to Visit
Criteria used to determine which sites
to visit were the following.
Liner type (membrane, clay, soil
sealant, etc )
Facility type (landfill, surface
impoundment, etc )
Construction schedule
Permission to take photographs
Experience of installation crew
Size of facility
Every effort was made to locate con-
struction sites representative of the five
liner types included in the project Sites
were eliminated from consideration if
photographs were not allowed and if the
construction schedule did not coincide
with the project schedule Whenever
possible, site visits were scheduled when
both subgrade preparation and liner
installation were in progress.
An installation summary was prepared
before each site visit detailing the
industry-recommended installation
practices, the desirable subgrade
characteristics, and the anticipated
activities This analysis was the basis for
comparing expected and observed
practice
Documenting Field Installation
Procedures
Field installation procedures and
subgrade characteristics were observed
at 21 facilities (Table 1) Onsite activities
were discussed with the person in charge
to clarify the rationale for observed
installation and subgrade construction
methods Every effort was made to
remain at the site long enough to observe
all aspects of liner installation
procedures Field placement procedures
and subgrade construction activities
were compared with the industry-sug-
gested practices during the site visit
Comments were solicited from the field
personnel regarding the reasons for
observed field activities
Results
Membrane Liners
Field observations at 14 flexible
membrane liner construction sites
Table 1. Facility and Liner Types Studied
Facility Type
indicate that installers generally follow
applicable industry recommendations
For all sites visited, considerable efforts
had been made to anticipate installation
problems and develop solutions
Crew experience varied considerably.
In one case, only the foreman had previous
installation experience, but in others, the
entire crew had previous experience In
all cases, either an experienced
installation crew chief was on site or a
technical advisor was present to
represent the manufacturer or fabricator
of the liner material The presence of at
least one experienced liner installer at a
given site appears to alleviate the severity
of installation problems and elevate the
overall quality of a given installation
Three installation activities appeared to
deviate from industry suggesnons at
more than one site (1) working during
marginal or adverse weather, (2) sealing
around penetrations, and (3) field
inspection or laboratory testing of field
seams Though an installer may be forced
to work m adverse weather (wet, hot, or
cold conditions), he can and should take
advantage of specialized tools and
techniques to mitigate the effects
Observed methods of sealing liners to
structural penetrations did not always
follow industry suggestions, particularly
when the installer had no input into the
sealing techniques specified At
approximately half of the sites visited,
little attention was paid to thorough
Liner Type
Tailings storage
Municipal landfill
Evaporation pond
Potable water storage
Municipal/industrial wastewater
Geothermal brine storage
Municipal landfill
Evaporation pond
Tailings storage
Potable water storage
Evaporation pond
Municipal landfill
Potable water storage
Evaporation pond
Hazardous materials landfill
Naptha spill containment
Industrial wastewater storage
Municipal landfill cover
Municipal wastewater storage
Cooling tower blowdown treatment
Fuel oil spill containment
Polymeric membrane
Polymeric membrane
Sprayed-on membrane
Polymeric membrane
Soil sealant
Polymeric membrane
Asphaltic concrete
Polymeric membrane
Polymeric membrane
Soil sealant
Ftecompacted clay
Soil sealant
Polymeric membrane
Polymeric membrane
Clay/polymeric membrane
Polymeric membrane
Polymeric membrane
Polymeric membrane
Polymeric membrane
Soil sealant
Polymeric membrane
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inspection of completed field seams.
Clay Liner
Construction activities at the clay liner
site visited indicated reasonable
adherence to industry recommendations.
The clay liner was compacted in 6-in. lifts
to slightly less than the recommended
height of 2 ft. Compaction densities of
less than the recommended 95 percent
were achieved. Construction occurred
during dry weather, allowing control of
water content in the clay.
Spray-On Liner
The installation of the observed
sprayed-on liner system complied with all
applicable industry recommendations.
An experienced field crew constructed
the liner under the supervision of the
asphalt manufacturer. Quality control
measures recommended by the manu-
facturer were followed.
So/7 Sealant Liner
Installation practices at the four soil
sealant (bentonite) liner sites varied as to
application methods and blending
techniques. Industry specifies the
importance of uniform application and
complete blending of the bentonite and
soil. Application equipment used at three
of the four sites appeared to produce
uniform distribution of bentonite, but the
method used at the fourth site did not.
Complete blending of the bentonite and
soil was achieved at two sites using
agricultural Rototillers, but it did not
appear to be complete at the two other
sites. The latter conclusion was based on
observation of the soil and not on
laboratory tests.
Asphaltic Concrete Liners
The observed asphaltic concrete liner
was installed according to industry
recommendations with one exception.
Hot asphalt was not sprayed on the
subgrade before concrete application.
The reason for omission of the hot liquid
asphalt is not known.
Conclusions
Field observations at 21 liner construc-
tion sites indicate that installers
generally complied with industry
suggestions regarding subgrade prepara-
tions and liner placement procedures.
Two important aspects of the flexible liner
industry that need development and
definition are quality control inspection
procedures and field seam testing
requirements. Several manufacturers
and installers of polymeric membrane
liners are developing and implementing
methods to test the quality of field seams.
Though the liner industry literature
suggests procedures for installation,
these must often be modified to
accommodate special site problems or
characteristics. Accommodation that
ensures reliable construction and
installation methods requires an
experienced, knowledgeable installation
crew that can adapt to various field
situations. At present, the final
responsibility for liner system
performance rests with the owner, who
should take an active part in the planning,
installation, and operation of a lined
surface impoundment or landfill. No
particular liner installation technique or
procedure guarantees a successful liner
system.
Facts about the impact of installation
procedures on successful systems are
not available to the entire technical
community involved in liner system
design, construction, and operation.
Factual, unbiased data are needed to
improve the overall quality and reliability
of liner systems.
Recommendations
1. Research should be done to deter-
mine the impact of installation
procedures and subgrade condi-
tions on liner system performance.
One approach would be to track the
performance of the liner systems
observed during this study
2. Research should be conducted to
develop methods for testing the
quality of field seams for membrane
liner systems. The most desirable
method would be nondestructive to
the liner so that all seams could be
tested. The method would also
need to be operable in the field.
The full report was submitted in
fulfillment of Grant No R806645010 by
Southwest Research Institute under the
sponsorship of the U S. Environmental
Protection Agency
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David W. Shultz is with Southwest Research Institute, San Antonio, TX 78284.
Robert E. Landreth is the EPA Project Officer (see below).
The complete report, entitled "Field Studies of Liner Installation Methods at
Landfills and Surface Impoundments," (Order No. PB 85-117 067; Cost:
$11.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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EPA-600/S2-84-168
ST
IL 60604
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