EPA-600/2-77-081
June 1977
Environmental Protection Technology Series
LINER MATERIALS
HAZARDOUS
First iwlerii ll|»rt
Environmental Research
Me of Research and Development
U.S. Environmental Protection Agency
4SI88
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are
1 Environmental Health Effects Research
2. Environmental Protection Technology
3 Ecological Research
4. Environmental Monitoring
5 Socioeconomic Environmental Studies
6 Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8 "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161
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EPA-600/2-77-081
June 1977
LINER MATERIALS EXPOSED TO
HAZARDOUS AND TOXIC SLUDGES
First Interim Report
by
Henry E. Haxo, Jr.
Robert S. Haxo
Richard M. White
MATRECON, INC.
Oakland, California 94608
Contract 68-03-2173
Project Officer
Robert Landreth
Solid and Hazardous Waste Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does men-
tion of trade names or commercial products constitute endorsement or recom-
mendation for use.
11
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FOREWORD
The Environmental Protection Agency was created because of increasing
public and government concern about the dangers of pollution to the health
and welfare of the American poeple. Noxious air, foul water, and spoiled
land are tragic testimony to the deterioration of our natural environment.
The complexity of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.
Research and development is that necessary first step in problem
solution and it involves defining the problem, measuring its impact, and
searching for solutions. The Municipal Environmental Research Laboratory
develops new and improved technology and systems for the prevention, treat-
ment, and management of wastewater and solid and hazardous waste pollutant
discharges from municipal and community sources, for the preservation and
treatment of public drinking water supplies, and to minimize the adverse
economic, social, health, and aesthetic effects of pollution. This publi-
cation is one of the products of that research; a most vital communicia-
tions link between the researcher and the user community.
Although the information contained herein is preliminary, it will
provide a guide and insight to the effects that happen after limited
exposure. This information and data could be useful for design purposes
if not taken out of context.
Francis T. Mayo, Director
Municipal Environmental Rsearch
Laboratory
iii
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ABSTRACT
The storage and disposal of hazardous liquids and solid wastes on the
land are increasing the potential for pollution of surface and ground waters
by these wastes or their leachates. Intercepting and controlling the seep-
age of such fluids by the use of impervious barriers offers a promising means
of reducing or eliminating such pollution.
This engineering research project was undertaken to assess the relative
effectiveness and durability of a wide variety of liner materials when ex-
posed to hazardous wastes. The materials under study include a native soil,
modified bentonite, a soil cement, a hydraulic asphalt concrete, an asphaltic
membrane, and 8 polymeric membranes based upon polyvinyl chloride, chlorin-
ated polyethylene, chlorosulfonated polyethylene, ethylene propylene rubber,
neoprene, butyl rubber, an elasticized polyolefin, and a thermoplastic poly-
ester elastomer, respectively.
In this study the liner materials are exposed to such hazardous wastes
as a strong acid, a strong base, an oil refinery tank bottom waste, a blend
of lead wastes from gasoline production, a saturated and unsaturated hydro-
carbon oil waste, and a pesticide.
The experimental approach and methodology followed are described and re-
sults of preliminary tests used in the selection of materials for extensive
testing are presented.
This report was submitted in partial fulfillment of Contract 68-03-2173
by Matrecon, Inc., under the sponsorship of the U. S. Environmental Protec-
tion Agency. This report covers a period from February 3, 1975, to October
31, 1976.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
Abbreviations viii
Acknowledgments ix
1. Introduction and Objectives 1
2. Summary of Work and Tentative Conclusions 3
3. Planned Future Work 5
4. Overall Approach and Research Plan 7
5. Design and Construction of Exposure Cells and Ancillary Equipment 9
Primary Exposure Cells 9
Rack for Holding Exposure Cells 14
Open Tubs for Weather Exposure of Membrane Liners 14
Silica Gravel 17
6. Selection and Properties of Liners 18
Admix Liners 19
Polymeric Membrane Liners 32
7. Selection and Characteristics of Wastes 40
8. Exposure Tests 42
Preliminary Exposure Tests 42
Filling of Exposure Cells with Wastes 50
9. Outdoor Weathering Tests of Membrane Liners 55
References 59
Appendices 60
A. Materials Used in Constructing Exposure Cells 60
B. Major Equipment 61
C. Materials for Admix Liners 62
v
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FIGURES
Number Page
1 Schematic drawing of the exposure cell for membrane liners .... 10
2 Schematic drawing of exposure cell for thick admix liners 11
3 Unassembled exposure cell used for thick admix specimens 12
4 Unassembled exposure cell used for membrane liners 13
5 Overall view of the rack holding exposure cells 15
6 View of cells on the rack 16
7 Leak-testing of hydraulic asphalt concrete specimen 22
8 Jig used in the compacting of soil and other admix materials ... 25
9 A compacted fine-grain soil liner specimen 26
10 Compaction of a soil-cement liner specimen with Tamper 1 29
11 Bench-scale tests of membrane liners partially immersed
in hazardous wastes 43
12 Bench-scale test of modified bentonite clays exposed to various
hazardous wastes 46
13 Bench-scale test of compacted soil samples exposed to hazardous
wastes 49
14 Equipment used in blending of wastes and filling of cells 53
15 Exposure rack loaded with polymeric membrane specimens 56
16 The open exposure tubs lined with polymeric membranes and par-
tially filled with hazardous wastes 58
VI
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TABLES
Number Page
1 Soil and Admix Liner Materials for Hazardous Wastes 18
2 Polymeric Membrane Liner Materials for Hazardous Wastes ..... 19
3 Testing of Admix Liner Materials 19
4 Water Permeability of Hydraulic Asphalt Concrete from Compacted
Slab for Preparing Liner Specimens
20
5 Hydraulic Asphalt Concrete - Penetration of Asphalt at 77 F . . . 20
6 Water Permeability of Laboratory Compacted Native Soils 23
7 Permeability of Compacted Liner Specimens of Fine-Grain Soil
from Mare Island 27
8 Water Permeability of Soil Cement Specimens 28
9 Water Permeability of Laboratory Compacted Modified Bentonite-
Sand Specimens 31
10 Testing of Polymeric Membrane Liners 35
11 Properties of Unexposed Polymeric Liners 36
12 Seams in Exposure Tests 39
13 Initial Characterization of Wastes 41
14 Effect of Immersing Liner and Sealing Materials in Hazardous
Wastes - A Preliminary Study 44
15 Effects of Placing Hazardous Wastes Above Test Specimens of Admix
Materials 47
16 Combinations of Liner Materials and Wastes Selected for Exposure
Testing in Cells and Open Tubs 51
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LIST OF ABBREVIATIONS
ABBREVIATIONS
COD — chemical oxygen demand
CPE — chlorinated polyethylene
EPDM — ethylene propylene rubber
HAC — hydraulic asphalt concrete
ipm — inches per minute
NT — no test
OT — open tub
PE — polyethylene
ppi — pounds per inch
ppm — parts per million
psi — pounds per square inch
PVC — polyvinyl chloride
SERL — Sanitary Engineering Research Laboratory, University
of California, Berkeley, CA.
THF — tetrahydrofuran
TVA — total volatile acids
NOMENCLATURE FOR LOCUS OF FAILURE IN ADHESIVE TESTING
AD — failure within the adhesive
AD-AD — failure between two coats of adhesive
AD-LS — failure between adhesive and liner surface
BRK — break of liner material outside of the seam
DEL — delamination of the liner material
LS — failure at liner surface
OR — failure of the reinforcing fabric
FACTORS FOR CONVERTING DATA IN U.S. CUSTOMARY UNITS TO SI METRIC UNITS
Inches to centimeters (cm) x 2.54
Feet to metres x 0.3048 _3
Mils to centimetres (cm) x 2.54 x 10_2
Mils to millimetres (mm) x 2.54 x 10 _3
Pounds per square inch (psi) to megapascals (MPa) x 6.895 x 10 ,
Pounds per inch (ppi) to kilo Newtons per metre (kN/m) x 1.751 x 10
Pound (force) to Newtons x 4.448
Vlll
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ACKNOWLEDGMENTS
The authors wish to thank Robert E. Landreth for his support and guid-
ance in this project. The also wish to acknowledge the guidance of Dr.
Clarence Golueke and Stephen Klein of the Sanitary Engineering Research Lab-
oratory, University of California, Berkeley, California, who were responsible
for the analyses and characterization of the wastes.
We also acknowledge the assistance of Messrs. Reuben Carter and Max Har-
rington of Mare Island Naval Shipyard, Vallejo, California, in obtaining the
fine-grain soil, and the cooperation of Messrs. Victor Johnson and Clair Steck
of Industrial Tank Company, in supplying the hazardous wastes.
The following companies contributed to this project by supplying samples,
information, and technical assistance:
American Colloid Company
Burke Industries, Inc.
Carlisle Tire and Rubber Company
Cooley, Inc.
Dowell, a Division of Dow Chemical Company
E. I. du Pont de Nemours and Company
Exxon Chemical Company
Firestone Tire and Rubber Company
Gaco Western, Inc.
B. F. Goodrich Company
Goodyear Tire and Rubber Company
Industrial Materials Company
Pantasote Company
Phillips Petroleum Company
Plymouth Rubber Company
Polysar Corporation
Quarry Products, Inc.
Ransome Company
Reeves Bros., Inc.
Staff Industries
Union Carbide Company
Watersaver Company
Witco Chemical Corporation
We also gratefully acknowledge the cooperation of The Asphalt Institute
and The Portland Cement Association.
IX
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SECTION 1
INTRODUCTION AND OBJECTIVES
Environmental Protection Agency's "Report to Congress on Hazardous Waste
Disposal" in 1973 (1) concluded that the then existing current management of
the nation's hazardous residues was "generally inadequate" and that the "pub-
lic health and welfare are being unnecessarily threatened by the uncontrolled
discharge of such waste materials into the environment". At that time it was
pointed out that approximately 10 million tons of nonradioactive hazardous
wastes were being generated per year, of which 60% were organic and 40% inor-
ganic. Of these wastes 90% occurred in liquid or semiliquid form. Genera-
tion of hazardous wastes is growing at the rate of 5 to 10% per year. How-
ever, at the same time, disposal on land is increasing even faster as a re-
sult of air and water pollution controls which require that those wastes be
converted into solid or semisolid form which must then be disposed of on land,
Ocean-dumping is becoming unacceptable for many wastes.
This increasing storage and disposal of hazardous wastes on the land in-
creases the potential for pollution and contamination of the surface and
ground water system. Positive measures are needed to prevent such occur-
rences.
Confining and controlling of hazardous wastes through the use of man-
made impervious liner materials appears to be a feasible means of preventing
the seepage of pollutants from the wastes entering and polluting the ground
water. Such methods have been used to varying degrees for impounding wastes
for the last 25 years. A great range of materials (2-7), differing in perm-
eability to water and potential wastes, composition, form and shape, and
costs, have been used or are potentially useful for confining a range of po-
tential pollutants. Nevertheless, available information as to the relative
performance and service lives of specific materials exposed to specific
wastes is meager. In order to be able to supply guidance and perhaps eventu-
al regulation for the use of liners in these applications, the Environmental
Protection Agency needs considerably more information.
This project was undertaken with the following broad objectives:
1. To determine the effects upon a selected group of liner materials of
exposing them to various hazardous wastes over an extended period of time.
2. To determine the durability of and the cost effectiveness of utiliz-
ing synthetic membranes, admixed materials, and natural soils as liners for
hazardous wastes storage and disposal ponds.
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3. To estimate the effective lives of 12 liner materials exposed to 6
types of nonradioactive hazardous waste streams generated by industry under
conditions which simulate those encountered in holding ponds, lagoons, and
landfills.
4. To develop information needed for selecting specific liner materials
for confining hazardous wastes in specific installations.
5. To develop a method for assessing the relative merit of the various
liner materials for specific applications and for determining their service
lives.
6. To aid the Environmental Protection Agency in developing effective
controls for the proper disposal and management of hazardous wastes.
This first interim report describes:
1. The methodology and research approach.
2. The construction of the exposure cells and the ancillary equipment.
3. The selection of the various liners and wastes.
4. The preparation of the admix liners.
5. The properties of the unexposed liners.
6. A preliminary experiment in which the compatibility of liners and
the wastes was determined as a part of the process to determine the combina-
tion of liners and wastes which should be tested.
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SECTION 2
SUMMARY OF WORK AND TENTATIVE CONCLUSIONS
One hundred forty-four cells, in which the various liner materials can
be exposed under conditions which partially simulate actual service condi-
tions, have been fabricated. These cells were designed to accept both mem-
brane and thick admix liner materials. The area of an individual specimen
exposed to the waste is 10 by 15 inches; waste 1 foot deep can be placed on
it. These cells are placed in a covered rack with each cell having an indi-
vidual cover. In addition, 12 plywood troughs with sloping sides were fabri-
cated for exposing liners under conditions which simulate those encountered
around the edges of waste ponds and lagoons.
Five types of admix materials were selected for the exposure testing.
These, with their respective thicknesses, are:
Asphalt emulsion on nonwoven fabric (0.3 in.).
Compacted native fine-grain soil (12.0 in.).
Hydraulic asphalt concrete (2.5 in.).
Modified bentonite and sand (5.0 in.).
Soil cement with and without surface seal (4.0 in.).
A total of 48 admix liner specimens have been placed in the cells.
Eight types of polymeric membrane liners were selected for exposure
testing. These, with their respective thicknesses, are:
Butyl rubber, fabric reinforced (34 mils).
Chlorinated polyethylene (32 mils).
Chlorosulfonated polyethylene, fabric reinforced (34 mils).
Elasticized polyolefin (20 mils).
Ethylene propylene rubber (50 mils).
Neoprene, fabric reinforced (32 mils).
Polyester elastomer, experimental (8 mils).
Polyvinyl chloride (30 mils).
Eighty-four membrane liner specimens have been mounted in the exposure
cells.
All membrane specimens were mounted with lap seams prepared either by the
suppliers of the liners or by the contractor in accordance with procedures
recommended by the suppliers. These seams are made by the same procedures
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as used in the field except that, being prepared in the factory or in the
laboratory, they are prepared under better conditions.
Six classes of hazardous wastes were selected for this study. They are:
Strong acid
Strong base
Waste of saturated and unsaturated oils
Lead waste from gasoline tanks
Oil refinery tank bottom waste (aromatic oil)
Pesticide waste
Twelve individual wastes were obtained and a preliminary characteriza-
tion was made of each. Eleven of these were satisfactory; however, only 4
were available in sufficient quantity to fill the cells. The 3 individual
lead wastes were combined to make a sufficient quantity of this class of
waste. At the time the cells were filled, a sufficient quantity of the tank
bottom waste to fill the primary exposure cells had not been obtained and con-
siderable difficulty Vas encountered in obtaining such a waste; arrangements
have now been made for delivery of 110 gallons of a waste of this type.
Preliminary exposure tests were run on the various liner materials in the
various wastes in order to select combinations for long-term exposure. It was
recognized that some of the liner materials would not be compatible with some
of the wastes. In these preliminary tests, most of the membrane liners and
all of the asphaltic materials either swelled or dissolved in the aromatic
hydrocrabons. Several combinations were thus eliminated, such as the asphalts
with oily wastes. It was also found that clays could only hold the acidic and
caustic wastes for short periods of time. These combinations were dropped
from the long term exposure tests.
At the present time 113 liner specimens are under exposure to 5 different
wastes in individual exposure cells. Two additional exposure tests are also
underway:
1. Small specimens (6 inches by 6 inches) of the membrane liners
are being exposed to the weather on racks. •
2. Larger specimens (4 feet by 4 feet) are being exposed to weather
and selected wastes as liners of small open tubs filled with the
wastes.
The results obtained to date on the limited bench-scale tests of liner
materials in the various wastes demonstrate that:
1. Liners should be carefully selected for specific wastes.
2. Liner materials should be subjected to preliminary exposure tests
in the wastes prior to selection of specific liners.
3. Oily wastes cannot be safely contained with asphalt-based liners.
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4. Oily wastes, particularly those containing aromatic components, may
pose special problems for polymeric membranes, except for those which are
crystalline. The noncrystalline materials, such as the rubbers and PVC,
swell to varying degrees in the oily wastes. Such swelling can be particular-
ly damaging to seams based upon cements.
5. The bentonite liners, polymer modified bentonite, and perhaps many
soils, may not be satisfactory for confining strong acids and bases and con-
centrated brines.
6. Wastes containing both aqueous and oily phases may also pose special
problems because of the need of the liner to resist simultaneously two fluids
which are inherently different in their compatibility with materials.
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SECTION 3
PLANNED FUTURE WORK
1. Expose liner specimens to the wastes through April 1978 and perform the
necessary monitoring of the primary exposure cells.
2. Continue the outdoor exposure tests of the liner specimens.
3. Complete the detailed analysis of the various wastes. This work is being
done by the Sanitary Engineering Research Laboratory of the University of Cal-
ifornia, Berkeley.
4. Dismantle half of the primary cells after approximately one year and the
remaining cells after two years of exposure, recover the liner specimens, and
determine the effects that the exposure to the wastes has had on their physi-
cal properties and permeabilities.
5. Increase the number of liners and individual wastes .in this investigation.
Additional specimens of liners will be immersed in the 6 wastes now in the
cells and in several wastes to be placed in additional cells. These liner
specimens will be sufficiently large so that major physical properties which
are being determined on the primary test specimens can be measured at 3 expos-
ure times.
6. Prepare test specimens of various liners in the shape of bags in which an
absorbent can be placed. Thus, specimens having only one side exposed to a
waste can be immersed at different depths in a pond.
7. Tabulate and analyze liner specifications furnished by the manufacturers
or suppliers to determine the various physical tests which are used by the in-
dustry. The relation of these specifications with field performance will be
determined.
8. Determine the major components of polymeric liners which are being used in
this test program. Analyses will include, at a minimum, ash, extractables,
and specific gravity. Of particular importance are the filler, plasticizer,
and polymer contents of all the major materials being studied under this con-
tract. Additional analyses, e.g. elemental and infrared, will be performed as
needed.
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SECTION 4
OVERALL APPROACH AND RESEARCH PLAN
To meet the objectives of this project the overall experimental approach
is to expose specimens of a variety of potential liner materials to selected
hazardous wastes over a period of several years under conditions which simu-
late real service and to determine the changes in physical properties and
permeability of these materials to the wastes with exposure time.
More specifically, the plan has been:
1. To select liner materials which are, or potentially could
be, used for lining ponds containing hazardous wastes.
2. To design and construct exposure cells simulating the con-
ditions under which liners would exist in a pond, which would act as
permeameters to measure actual seepage, if any occurs.
3. To select a range of hazardous wastes of various types which
would be encountered in industry.
4. To characterize the wastes fully so that the behavior of
specific liners can be predicted for exposure to actual wastes in a
given installation.
5. To perform exploratory tests of liners and wastes to deter-
mine their "compatibility" and suitability for long-term exposure tests.
6. To expose liner specimens of about one square foot in area
which are sealed in the bottom of cells and covered with approximate-
ly one foot of waste. Field type seams would be incorporated in all
polymeric membrane liners.
7. To measure the seepage of the wastes through the liners and
to determine the composition of each fluid which is collected below
the liner specimen.
8. To measure the properties of the liners as a function of ex-
posure time of up to about 3 years.
9. To determine the changes in the properties of small speci-
mens of a wide range of liner materials immersed in the same wastes.
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10. To expose samples of selected liners to the weather and
wastes simultaneously by placing in tubs partially filled with the
wastes.
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SECTION 5
DESIGN AND CONSTRUCTION OF EXPOSURE CELLS AND ANCILLARY EQUIPMENT
The exposure cells and the special equipment and materials required for
this project are discussed in this section. They include the following items:
1. The primary exposure cells in which the liner membranes
are being tested in contact with wastes.
2. The rack in which the loaded exposure cells are mounted.
3. The open tubs lined with selected membranes, filled with
wastes, and exposed to the weather.
4. A highly inert silica gravel for filling the bases of the
exposure cells.
PRIMARY EXPOSURE CELLS
The individual exposure cells were designed to perform as permeameters
and to be adaptable to liners of thicknesses ranging from 20 mils to 12 inches,
as shown schematically by Figures 1 and 2, for membranes and thick liner spec-
imens, respectively. They provide for a test specimen 10 by 15 inches in area
and a volume of waste of approximately 1 cubic foot, at a depth of 1 foot.
Photographs of the exposure cells for thick admix specimens and for membrane
liners are shown in Figures 3 and 4, respectively.
144 cells were fabricated from 11-gauge steel, coated on the inside with
a chemically resistant epoxy coating, Epoxy 3, and on the outside with a rust-
preventative paint. (See Appendix A for details regarding materials used in
constructing cells and mounting liner specimens.)
After coating the first 24 cells with paint brush and pad, it was de-
cided that a more economical way to coat the remaining 120 cells was by spray-
ing. A jig was constructed to facilitate the coating of the cell tank interi-
ors. The cell bases were laid out next to each other on long tables so that
20 could be sprayed as a group.
The spraying of the primer presented no problem as its viscosity was
within the medium range for paint. Spraying of the two-part epoxy coating,
Epoxy 2, was somewhat more difficult; a quart of the mixed coating has a pot-
life of 42 minutes at 77 F, and a viscosity of 30 poise, the consistency of a
very heavy paint.
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One coat of the primer was applied, followed by a coat of the two-part
epoxy coating, Epoxy 2. A second coat of Epoxy 2 was applied along the bottom
weld on the tank sections. All coatings were tested for pinholes with a spark
tester. After 9 months of exposure there is no indication of failure or sof-
tening of the coating in any of the cells.
The bases of the cells were finished similarly to the tanks. They were
filled with a chemically-inert high quality crushed silica in order to prevent
reactions and contamination of the waste which may seep through the liner.
Spacers for mounting the admix liners were fabricated. These spacers
varied in height depending on the thickness of the liner. For those liners
compacted-in-place, i.e. the soil cement, native soil, and the modified bento-
nite, the inside surfaces were coated first with the primer and Epoxy 2, and
then with a second coat of Epoxy 2 sprinkled with sandblasting sand. A rough
wall surface should reduce or eliminate a wall effect which might result in
the waste by-passing the liner. A ring seal of epoxy-sand was cast around the
periphery of the admix specimens to increase path length of the waste seeping
through the liner and to reduce wall effects and channeling. The rings were
cast of Epoxy 1 and Epoxy 2 filled with sandblasting sand (See Appendix A).
Lids for each of the 144 cells were fabricated of hardboard, wood, and
polyethylene, and installed on the filled cells. These lids reduce water loss
by evaporation and prevent accidental contact with the hazardous waste by peo-
ple or animals, but are not intended to be either water or air tight.
RACK FOR HOLDING EXPOSURE CELLS
The exposure cells were mounted on a rack constructed outdoors on a con-
crete slab at the Richmond Field Station of the University of California, Berk-
eley. This rack consists of 6 sections, each of which can hold 24 exposure
cells. Each section has 2 tiers and is 4 feet by 8 feet by 3 feet. These 6
sections are arranged in 2 rows of 3 sections each which are placed 4 feet
apart, as shown in Figures 5 and 6. A corrugated plastic cover was construc-
ted over the rack at a height of 8 feet to protect the cells from rain and sun-
light. The design of the racks affords good accesr, to the cells; each can be
removed or replaced with relative ease.
Although the cells are outdoors, they are well protected from the heat of
the sun. The temperature is relatively uniform, generally in the range of 50
to 60 F, and does not drop below freezing.
OPEN TUBS FOR WEATHER EXPOSURE OF MEMBRANE LINERS
Twelve open plywood exposure tubs, 20 x 24 x 10.75 inches, were construc-
ted. These tubs have sloping sides, about 1:2 slope, which allow the liners
to be exposed to intermittent immersed-in-waste, exposed-to-weather cycles.
Such conditions exist along the sides of operating hazardous waste ponds.
Since these plywood tubs are open to the weather, they reqaire continual
monitoring to prevent excessive evaporation, or overfilling from rain. They
14
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are placed in 2 shallow basins (8 feet by 6 feet by 4 inches) which can con-
tain any accidental spills.
SILICA GRAVEL
The gravel used to fill the cell bases and support the liners was quartz
from the Bear River (California), selected because of its high silica content
(99%) and low content of constituents soluble in acid which might contaminate
any of the wastes which percolate through the liners. The nominal size used
was 3 to 6 mm (1/8 to 1/4 inch). Individual pieces were as long as 25 mm in
one dimension, since the gravel had been crushed in a jaw crusher which tends
to produce a high percentage of long and flat particles. The gravel was
thoroughly washed and dried before placing in the bases.
17
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SECTION 6
SELECTION AND PROPERTIES OF LINERS
A wide range of materials are potentially useful as barriers for im-
pounding hazardous liquids and sludges (2-7). Many are currently being used
to line ponds, reservoirs, lagoons, and canals to reduce or, if possible,
eliminate the seepage of liquids into the ground. These liners vary consid-
erably in permeability, durability, and cost. Selection of a liner for a giv-
en installation depends upon many factors, such as the character of the waste
being confined, soil conditions, availability of materials, the level of per-
formance required, the design life of the pond and cost.
Compacted soils, clays, soil cements, and asphaltic materials have found
wide use for lining reservoirs, ponds, and other water-retention facilities.
Many materials have limitations, particularly in respect to their permeability
to other liquids, e.g. brines and oils.
The synthetic polymeric membranes are of particular interest because of
their low permeability. However, they can vary considerably in physical and
chemical properties, installation, overall performance, and costs. In addi-
tion, even for a given polymer, there can be considerably variation in the
liners among producers due to compound, design, and manufacturing differences.
After reviewing the available liner materials, 5 admix type and 8 spe-
cific polymeric membrane materials were selected for exposure testing as lin-
ers in cells loaded with various wastes. These materials are listed in Tables
1 and 2.
TABLE 1. SOIL AND ADMIX LINER MATERIALS FOR HAZARDOUS WASTES
. , Thickness
Material . . ,
in inches
Asphalt emulsion on nonwoven fabric 0.3
Compacted native fine-grain soil 12.0
Hydraulic asphalt concrete 2.5
Modified bentonite and sand 5.0
Soil cement with seal 4.0
18
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TABLE 2. POLYMERIC MEMBRANE LINERS FOR HAZARDOUS WASTES
., ^ . , Thickness
Material . ..
in mils
Butyl rubber, reinforced 34
Chlorinated polyethylene (CPE) 32
Chlorosulfonated polyethylene, reinforced 34
Elasticized polyolefin 25
Ethylene propylene rubber (EPDM) 50
Polychloroprene (neoprene), reinforced 32
Polyester elastomer 8
Polyvinyl chloride (PVC) 30
ADMIX LINERS
The admix liners were selected or designed to yield permeability coeffic-
ients of 10 cm/sec or less. In the case of the soil cements and compacted
fine-grain soils, a series of compositions was compacted in order to achieve
the desired coefficient of permeability. Though water permeability was the
primary test in evaluating admix materials, other tests appropriate to the
specific materials were also used. The tests used in evaluating the admix
materials are given in Table 3.
TABLE 3. TESTING OF ADMIX LINER MATERIALS
Water permeability - back-pressure permeameter (10).
Density and voids - ASTM D1184 and D2041.
Water swell - California Division of Highways 305.
Compressive strength - ASTM D1074.
Penetration of asphalt - ASTM D5.
Viscosity, sliding plate of asphalts - California Division
of Highways 348.
Sources of materials for admix liners are given in Appendix C. Details
regarding the individual liner materials are presented below.
Hydraulic Asphalt Concrete
The mix design used for the hydraulic asphalt concrete (HAG) liner speci-
mens called for dense-graded aggregate to \ inch maximum size and 9 parts of
asphalt AR-4000 per 100 aggregate. The concrete was prepared in a hot-mix
plant.
19
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The one-half ton batch of hydraulic asphalt concrete was hauled 5 miles
to the test site in an insulated trailer, raked into a form (10 feet by 3.5
feet by 2.25 inches), and levelled with a wooden screed. Temperature of the
mix during placing was 345 F. Compaction was started when the mix had cooled
to 275 F and was performed using a gasoline-powered "Jumping Jack" rammer with
a 10 inch by 10 inch compacting foot. Compaction was continued for one-half
hour, at which time the HAC began to stick to the compactor foot. The HAC was
quite plastic, and some asphalt bled to the surface.
A one-gallon sample of uncompacted HAC and a one-quart sample of the
AR-4000 asphalt (from the tank at the mixing plant) were retained for labora-
tory tests. After the compacted HAC had cooled overnight, 14 two-inch diam-
eter cores were cut. Water permeability measured on 6 of the cores ranged
from 2.8 x 10 to 1.7 x 10~9 cm/sec. (see Table 4). Later, the compacted
pavement was cut with a diamond saw into specimens 11.75 inches by 17 inches
to fit in the spacers for mounting in cells. The consistencies of the orig-
inal asphalt and extracted asphalts, as measured by penetration values, are
presented in Table 5. These data show the hardening of the asphalt which
takes place during mixing, and compaction.
TABLE 4. WATER PERMEABILITY OF HYDRAULIC ASPHALT CONCRETE FROM
COMPACTED SLAB FOR PREPARING LINER SPECIMENS.
Core
5
7
12
16
16
17
18
Location on Slab
Near last end compacted
Near last end compacted
Near last end compacted
Near first end compacted
Top slice removed
Near first end compacted
Near first end compacted
Coefficient of
cm/sec
6.6 x 10~9
-8
2.8 x 10
-8
2.1 x 10
< 1 x 10~8a
-8-
1.7 x 10
< 1.5 x 10~
-9
ca 1.7 x 10
Permeability
in/yr
0.08
0.34
0.26
< 0.12a
0.21
< 0.19a
ca 0.02
Because of long test runs the specimens were removed from test
before constant values were obtained.
TABLE 5. HYDRAULIC ASPHALT CONCRETE3 -
PENETRATION OF ASPHALT AT 77°F.
Penetration of asphalt, unmixed, from tank to hot mix plant 138
Penetration of asphalt, extracted from uncompacted HAC 96
£
Penetration of asphalt, extracted from cores of compacted HAC 80
Dense-graded aggregate (h inch max), 100; asphalt 9.0.
AR-4000, ASTM D5 .
Extractable 8.4 parts per 100 aggregate.
20
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Each specimen was sealed into a 3.5 inch spacer. The specimen was first
placed on a cell base which had been filled with silica gravel. A spacer was
placed around the specimen and a wax-coated metal form was placed on top of it
to form a ring. The space between the spacer, the liner, and the base wns
filled with a grout consisting of Epoxy 1 (2 Part A:l Part B:3 sand). Grout
of similar composition was used to cast the ring above the specimen.
The HAC liner specimens were prepared and placed in the cells early in
the project. When they were tested with water prior to adding wastes (Figure
7), 5 were found to leak between the spacer and the epoxy seal, probably the
result of difference in thermal coefficients of the steel and the asphalt con-
crete. Five of the asphalt concrete specimen-spacer combinations were chilled
and the steel spacers were removed. The surfaces of the epoxy seal were rough-
ened, and the new spacers were cast of Epoxy 2 around and on top of the epoxy
seal. This was accomplished through the use of a wax-coated steel form and a
wooden outer form. The cast epoxy spacers consisted of Epoxy 2 filled with
sand (2 PartA:l Part B:4.5 sandblasting sand) with a thin layer of unfilled
Epoxy 3 poured on top to form a level surface. Neoprene sponge gaskets were
used to seal the joints between the spacers and exposure cell tanks as in all
the other cells.
Emulsified Asphalt on Nonwoven Fabric
Specimens of emulsified asphalt applied on a nonwoven polypropylene fab-
ric mat were furnished by the supplier in 18 inch by 24 inch sheets, 0.3 inch
thick, with a seam running across the width at the center. These sheets were
cut to a size which would fit loosely inside the 1.25 inch spacer.
When mounting this liner, the cut sheet was placed on a base filled with
crushed silica gravel; the spacer was placed around the liner, and an epoxy
ring was cast around the inside of the spacer. The epoxy resin was spread on,
around, and slightly under the edge of the liner. This ring of epoxy seals
the liner to the base and the spacer, so that no waste can by-pass the liner.
The epoxy ring was a grout consisting of sand-filled epoxy resin (Epoxy 1:2
Part A:l Part B:3 sand, and 2% thixotropic agent). The assembled cells were
leak tested by filling with water; none of the seals leaked. (No leak has
developed in any of these cells during the first 9 months of exposure.)
Compacted Natural Fine-grain Soil
Selection of soil—
An extensive search was required for native fine-grain soils which would
have the low level of permeability desired and minimal interaction with the
wastes. Several fine-grain soils, at various water contents, were evaluated
in the laboratory by measuring the permeability of compacted specimens with
the back pressure permeameter (10). It was desired to determine the minimum
permeability which could be obtained with a given soil. The results are
shown in Table 6.
The soils included materials used for "mudjacking" of portland cement
concrete pavement, clays used for constructing tennis courts and baseball
diamonds, a soil used to line a waste pond at a power plant in Nevada, and a
21
-------
1
to
0)
-p
o
u
w
-H
O
0)
ft
0)
-p
0
c
o
u
4
ft
w
n)
u
-•H
V) T3
O W
(0
en a)
a n
•H ft
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W (U
Q) M
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rd
-------
"Waste fines" which had been used to construct an impermeable cover over a
chemical waste dump. (The last soil was selected for the soil cement.) The
soil selected for use in the hazardous waste cells is a very fine silt that
had been dredged from the Carquinez Straits and the lower Napa River and ob-
tained at the Mare Island Naval Shipyard, Vallejo, California. Permeability
of cores cut from the water-laid deposits was between 10~' and 10~8 cm/sec.
Permeability in the same range was measured on laboratory-compacted specimens
prepared at water contents ranging from 14 to 30 parts of water per 100 parts
dry soil (Table 6) . Sieve analysis of the Mare Island soil showed more than
98% passing the 200 mesh sieve (ISft-io.) and almost 95% passing the 325 mesh
sieve (45 xtm) .
TABLE 6. WATER PERMEABILITY OF LABORATORY COMPACTED NATIVE SOILS
Soiia
Topsoil King clay
Topsoil King "mudjacking"
Topsoil Ling "mudjacking"
Moapa , Nevada , #2
Moapa, Nevada, #2
Quarry Products, "wastes fines"
Quarry Products, "wastes fines"
Mare Island
Mare Island
Mare Island
Mare Island
Mare Island
Mare Island
Mare Island
Water,k parts
per 100 dry
soil
10
10
11
15
17
12
15
30
28
25
20
18
16
14
Coefficient of
cm/ sec
-5
4.0 x 10
1.8 x 10~5
7.9 x 10"6
-7
1.7 x 10
-8
4.1 x 10
-6
4.9 x 10
-7
2.8 x 10
-8
8.2 x 10
-8
7.8 x 10
-8
9.0 x 10
-8
6.5 x 10
-8
7.3 x 10
7
1.1 x 10
-7
1.2 x 10
Permeability
in/yr
497
223
98
2.10
0.51
61.0
3.5
1.02
0.97
1.12
0.81
0.91
1.37
1.49
Carbonate content of soils: Quarry Products soil contains some carbonate;
Moapa soil contains more carbonate; Mare Island soil contains no carbonate.
Soils mixed with various amounts of soil, compacted, and tested to determine
water content to achieve minimum permeability.
Preparation of Compacted Soil Liners in Cells—
The 13 inches high spacers, coated with primer, Epoxy 2, and sandblasting
sand, were used for holding the native soil liners.
An attempt was made initially to compact the soil in a spacer which had
been bolted on the base, but the assembly was too flexible; the bottom of the
base and the sides of the spacer flexed with each impact of a tamper. The
23
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bond between the soil and the spacer was not tight. Also, it was felt that
the lowest potential water permeability was not achieved. Therefore, a wooden
frame was constructed (Figure 8) in which the spacer was held tightly to pre-
vent bulging of the sides and the whole assembly was bolted to a concrete
floor. A piece of polyetheylene film was placed on the floor and the soil com-
pacted on it. This film was removed before the liner was mounted in the base.
The 3 tampers used in compacting this soil, as well as the soil cement
and clay specimens, are described below:
Tamper 1: Weight, 6.8 kg (15 Ib)
Face, flat square, 125 x 125 mm (5 x 5 in)
Tamper 2: Weight 7.3 kg (16 Ib)
Face A, flat round, 50 mm diam. (2 in)
Face B, "sheep's foot", 13 mm diam (0.5 in)
Tamper 3: Face, flat rectangular, 20 x 40 mm (0.75 x 1.5 in)
Struck with 1 kg hammer (2 Ib)
Because of its plastic nature the Mare Island soil could not be blended
with the soil-shredder as was done with the soil used for the soil-cement lin-
ers. Near or above its optimum moisture content, the soil was too sticky to
pass through the shredder and, when drier, it was too hard causing the shred-
der to stall. Therefore, soil for the liners was blended by taking small
scoopfuls from each of the bags of soil. Lumps that were dry or unusually
wet were discarded. Soil for each lift (1.5 to 2 inches loose, compacted to
1 to 1.25 inches) was placed in the spacer, crushed and levelled with Tamper 1
and compacted by repeated tamping with Tamper 2 using alternately a 2 inch
diameter flat face "A" and a \ inch diameter "sheep's foot" face B. Final
compaction of each lift was with the "sheep's foot" to provide a rough surface
for keying to the next layer. The edges were compacted with Tamper 3 struck
with a hammer, twice around all edges for each lift. The top layer of each
liner was levelled, after compacting, by additional tamping with Tamper 1.
The compacted soil liner is shown in Figure 9. These liners were covered
with polyethylene film and protected from drying until mounted in the cells.
The cell bases were filled with the silica gravel levelled to support
the soil. After the liners were mounted in the cells a ring of Epoxy 1 was
cast into a triangular groove cut into the soil around the periphery of the
liner. The outside of the joint between the spacer and the cell was sealed
with butyl caulk.
Permeability measured on cores cut from compacted soil liners was slight-
ly more permeable than the cores from the water-laid deposits in place at Mare
Island. The permeability meaurements on the compacted liners are shown in
Table 7.
Soil Cement
Selection of Soil—
Most of the fine-grain soils being considered for use as compacted native
soil liners were evaluated in soil cement mixes. Formulations containing
24
-------
K5 EH T3
0)
1-1 rH
Q) • ,Q
-POO)
O -H en
•P CQ
MH O (0
O rcf
CL, in
G O
•!—>
•H G
O -H CO
W i-i -rH
M-) Tf -P
O
cn o -H
c o
0) rH CO
6 -P
•H frt
oo
cu
g.
•H
25
-------
0)
M
Q)
U
2U..
- H 4->
a) tn
g C
01
14-1 H
tn o
ft x:
U -P
C
•H
C C
•H ?
O
c x:
U
o ft
Q S
o
T3 U
Q) Q)
C (fl
•H (fl
•H i-l
O (U
W U
•O S
(1)
I 1 ti
U 0)
(0 C
ft *H
I H
O 0) O
-H M-l
U
0) 0)
ft '
ii t
(u ,n
4-1
U O
(0 4-1
ft
§ ^
tn 4-)
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0) X
CTi
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Cn
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0)
W
26
-------
TABLE 7. PERMEABILITY OF COMPACTED LINER SPECIMENS OF FINE-GRAIN SOIL FROM
MARE ISLAND
„ ,. _ Coefficient of Permeability,
Source of Specimen .
cm/sec.
a —8 — 7
Laboratory-prepared specimens (7 samples) 6.5 x 10 to 1.2 x 10
Core from specimen compacted in
spacer on cell base
Core from resilient end of cell 4.5 x 10
Core from firm end of cell , 1.7 x 10
Core from 12-inches thick specimen compacted
in spacer in jig on concrete floor (2 samples) 9.4 x 10 and 4.2 x 10
Core taken from water-laid deposits of the _
soil (3 samples) 1.0 x 10 to 1.0 x 10
See Table 6.
various proportions of soil:portland cement:water were molded into briquets,
cured, and tested in the back-pressure permeameter. The lowest permeability
was obtained with soil cement based on "waste-fines" from a local quarry, with
12 parts of Type 5 (sulfate-resistant) Portland cement per 100 soil, and 12%
of water on the total of soil plus cement (see Table 8). The "waste fines"
material is available in large quantities as a by-product of the washing of
crushed graywacke and has been used as a compacted soil cover (not a soil ce-
ment) over a chemical waste dump. Sieve analysis (wash) of the soil was:
Sieve size ^
: % Passing
Mesh Opening,/*m 2-
50 300 98
100 150 93
200 75 83
325 45 70
The "wastes fines" soil was received mostly in large friable lumps that
were broken up by passing the soil twice through a shredder to yield a thor-
ough blend with maximum agglomerate size of approximately 1/8 inch (3 mm).
The soil was air-dried on a concrete slab then stored indoors until used.
Preparation of Compacted Soil Cement Liners—
The soil cement specimens were compacted in 5-inch high spacers; the in-
ner surfaces were coated with epoxy and sand. The compaction procedure was
the same as used with the fine-grain soil; the spacer was placed within a sup-
porting wooden frame (Figure 8) to prevent bulging of the sides and the frame
and spacer were bolted to a concrete floor. A piece of polyethylene film was
placed on the concrete floor at the bottom of the spacer.
For each liner, 50 Ib. of dry soil was thoroughly mixed in a mortar boat
with 6 Ib. of Type 1-2-5 portland cement, then with 6.7 Ib. of water. The
mixed soil-cement was crumbly and barely damp before compaction. One-inch
27
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TABLE 8. WATER PERMEABILITY OF SOIL CEMENT SPECIMENS
Composition
Soil
Topsoil King clay
Topsoil King clay
Topsoil King clay
Topsoil King clay "mudjacking"
Topsoil King clay "mudjacking"
Topsoil King clay "mudjacking"
Quarry Products soil
Quarry Products soil
Quarry Products soil
Type V
cement
parts
8
10
12
8
10
12
10
12
ioa
Water
parts
10
10
10
12
12
12
13
12
12
Coefficient of
permeability
cm/sec . in/yr
1.6 x 10~6 20
1.3 x 10~6 16
-6
5.1 x 10 63
-6
3.4 x 10 42
5.3 x 10~6 66
-6
6.5 x 10 81
1.9 x 10~6 24
-7
1.5 x 10 1.9
2.9 x 10~L-, 3.6
4.0 x 10 5.0
Core from specimen compacted
in spacer in cell base
12
13.4
5.7 x 10
-8
0.71
Rice hull ash cement (an acid-resistant cement).
Repeat.
lifts were placed in the spacer and compacted with Tampers 1, 2, and 3, de-
scribed previously. Figure 10 shows the compaction of the soil cement with
Tamper 1. Final compaction of each lift was with the "sheep's foot" Face B
of Tamper 2, to provide a rough surface for keying to the next layer. The
edges were compacted with Tamper 3, twice around all edges for each lift. Af-
ter a total compacted thickness of 4 inches was obtained, the top surface was
levelled by additional tamping with Tamper 1. The compacted soil cement was
quite firm, but plastic enough to be compacted without cracking or shattering.
The thickness of the compacted liner specimens was 3.75 to 4.0 inches. One-
half gallon of water was poured on the surface and the soil cement was cured
for at least 7 days.
The surfaces of the cured liners were then allowed to dry only enough to
provide good adhesion for an epoxy ring cast around the periphery of the lin-
er, sealing the liner to the spacer, and for application of two coal-tar mod-
ified epoxy surface sealing coatings to portions of the liner surfaces. Af-
ter the epoxies cured, the liners were again flooded with water until being
filled with wastes. Each spacer was mounted on a cell base which had been
filled with crushed silica gravel levelled to support the liner. Neoprene
sponge gaskets were used to form seals between the flanges of the spacers and
the cell tanks. After the cell base, the spacer with sealed-in liner, and the
exposure tank were bolted together, a bead of butyl caulk was applied to the
outside of the base-to-spacer junction to make it airtight.
'28
-------
29
-------
Application of Surface-sealing coatings—
Two sections of each soil-cement liner were coated with two coal-tar
epoxy resin sealers. These sealers and the primer used for one of them were
2-component systems. Each was mixed according to the manufacturer's direc-
tions, and applied by brush. The areas coated were 6 inches square, located
at one end of the cell, as shown below.
Coating K
Coating C
Uncoated
Coating K = 3 coats proprietary epoxy bituminous coating (first coat diluted,
2 parts:! part thinner, according to manufacturer's instructions), average
total thickness 0.044 inch.
Coating C = 1 coat primer, 0.007 inch, plus 2 coats proprietary epoxy-tar
coating, 0.018 inch; total thickness 0.025 inch.
Treated Bentonite Clays
Selection—
Two polymer modified bentonite clays, claimed by their respective sup-
pliers to be more effective than unmodified bentonite in the presence of dis-
solved salts, were included in the study. Laboratory specimens were prepared
with 6%, 12%, and 20% of each treated bentonite in a well-graded
sand, and briquets were compacted with various water contents to determine
optimum moisture content for compaction to maximum density. Sieve analysis
of the sand used was:
Sieve size % Passing
96
80
50
15
2.6
As the sand-clay compositions were not strong enough to be tested without
support, specimens at the optimum moisture content were compacted in brass
tubes for testing in the back-pressure permeameter. Permeability coefficients
were in the range of 10~7 to 10~10 cm/sec, as shown in Table 9.
Mesh
8
16
30
50
200
Opening, m
2360
1180
600
300
75
30
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TABLE 9. WATER PERMEABILITY OF LABORATORY COMPACTED MODIFIED BENTONITE-
SAND SPECIMENS.
Composition
Sand
94
88
80
Water
12
12
12
Bentonite
6
12
20
Coefficient of Permeability, cm/sec.
Clay A
5.0 x 10~7
7.4 x 10~9
8.0 x 10~10
Clay B
7.1 x 10~8
2.8 x 10~9
3.5 x 10~9
Preparation of Treated Bentonite Liner Specimens—
The polymer modified bentonite liner specimens were compacted in the 7-
inch high spacers. Each spacer was placed on a cell base previously coated
with Epoxy 2; the outer flange of the base was slightly roughened with sand-
paper to insure good adhesion of the epoxy. Masking tape was pressed around
the flange between spacer and base, and a wax-coated metal form was placed on
the base inside the spacer. Between the form and the spacer an epoxy seal,
approximately h inch high by 1 inch wide, was cast using the grout of the
Epoxy 2 and sandblasting sand. After the seal was cured and the form removed,
the base was filled with crushed silica gravel to the level of the bottom of
the seal. The gravel was covered with woven glass fabric and the wooden re-
inforcing frame was bolted around the spacer. The clay-sand mixtures were
compacted in the spacer following the same procedure and with the same tampers
used in compacting the fine-grain soil.
Eight liner specimens were fabricated using 12% Clay B, 88% well-graded
sand, mixed at optimum moisture content and compacted in the liners already
sealed to bases. For each liner, 53.5 pounds of sand containing 3% water was
mixed in a mortar boat with 5.5 pounds more water and with 7.1 pounds Clay B.
This mixture was placed in the prepared spacer in 1-inch lifts, and each lift
was compacted with tampers. The compacting effort was less than that used for
the native soil and soil cement liners, to avoid damage to the epoxy seal be-
tween the spacer and the base.
Two liner specimens were fabricated using 20% Clay A and 80% well-graded
sand mixed at 3% water content. They were also prepared in spacers.
The compacted Clay B liners were 5 inches thick and the dry-tamped Clay A
liners 4 inches thick. Both were about 6 inches thick after complete hydra-
tion.
A sealing ring of Epoxy 2 grout was cast around the top edge of each of
the compacted specimens.
Two gallons of tap water was added on each liner through a perforated
can to avoid displacing the tamped sand-clay. After one day thickness in-
creased from 4.0 to 4.5 inches and after one week to 4.75 inches. One week
was allowed for "fresh-water hydration",as per manufacturers recommendation,
before draining the excess water and adding wastes.
31
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POLYMERIC MEMBRANE LINERS
Flexible polymeric membranes are assuming increased importance as liner
materials because of their very low permeability to water and other fluids.
These liners are products of the plastics and rubber industries. The poly-
meric materials used in the manufacture of these liners include vulcanizable
and nonvulcanizable (thermoplastic) plastics and rubbers. They are all syn-
thetic materials, varying from highly polar polymers, such as polyvinyl chlor-
ide, to nonpolar polymers, such as EPDM and butyl. They range from amorphous
polymers, such as the rubbers, to crystalline polymers, such as polyethylene.
Generally, polymeric materials are compounded with fillers, antidegradants,
plasticizers, and, if vulcanization is needed, curatives. Compounds based on
the same polymer can vary considerably in composition from manufacturer to
manufacturer, depending on the grade and the price of the liner.
The membrane sheeting is usually made in a continuous process by plying
together two thin sheets formed by passing the compound through the rolls of a
calender. Plying two sheets together to make a membrane almost eliminates pin-
holes. Fabric reinforcement, usually a nylon or polyester scrim, can be sand-
wiched between these plies to give added strength to the liner. Sheets are
typically 4 to 5 feet wide and 200 feet long. Several of these sheets are
seamed by a fabricator in a factory to form a panel.
These panels are brought to the site and seamed in the field to make the
final liner. Field seaming is one of the major problem areas in the use of
polymeric liners. Heat sealing, cementing, and solvent' welding are used both
in the factory and in field seaming. Seaming of vulcanized sheetings have
presented the most problems, particularly in the field as cold-curing adhes-
ives are required.
In making the selection of specific membrane materials for exposure tests,
consideration was given to the following:
1. The need for a broad representation of polymer types in order to
assure compatibility of liners and wastes, because of the great, di-
versity in the composition of wastes.
2. Availability of several membrane liners which are under investi-
gation for resistance to sanitary landfill leachate (4,8,9). They
offer promise for impounding hazardous wastes and allow an intensive
study on the characteristics of a few liners.
3. Equal thickness for liners, if possible. Most of the liners are
available in 30 mil thicknesses; however, if this thickness is not
available for the specific membrane then the thickness normally manu-
factured would be used.
In making the selection it was not possible to obtain liners from all
liner producers. Representative liners of the respective types were selected.
If several membranes of a given polymer were available, the membrane exhib-
iting the best physical properties was generally selected.
32
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The specific polymer types which are included in the major portion of
this study are discussed below.
Butyl Rubber
Butyl rubber is a copolymer of a major amount of isobutylene (97%) and a
minor amount of isoprene to introduce unsaturation in the rubber as sites for
vulcanization. A vulcanized butyl rubber compound is used in the manufacture
of the sheeting, which is available in either unsupported or fabric-reinforced
versions of 20 to 125 mil thickness. Butyl rubber has excellent resistance to
permeation of water and swelling in water. This rubber has poor resistance to
hydrocarbons, but is quite resistant to animal and vegetable oils and fats.
Butyl rubber compounds generally contain low amounts of extractable material
and swell little in water. Overall they age very well, although some butyl
compounds ozone crack. Some recent compounds contain minor amounts of EPDM to
improve ozone resistance. In outdoor exposure in water management use, butyl
rubber liners have shown no degradation after 20 years of service. Obtaining
good splices of butyl sheeting, particularly in the field, continues to be a
problem, as cold curing adhesives are required.
Chlorinated Polyethylene (CPE)
This relatively recently developed polymer is an inherently flexible
thermoplastic produced by chlorinating high density polyethylene. Sheeting of
CPE makes durable linings for waste, water, or chemical storage pits, ponds,
or reservoirs. CPE withstands ozone, weathering and ultraviolet and resists
many corrosive chemicals, hydrocarbons, microbiological attack, and burning.
Compounds of CPE are serviceable at low temperatures and are nonvolatile.
Membranes of CPE are available in 20 to 40 mil thicknesses in supported and
reinforced versions. They are generally unvulcanized and are spliced with
solvent adhesives by solvent welding.
Chlorosulfonated Polyethylene
This synthetic rubber is made by the chlorosulfonation of polyethylene.
It can be used in both vulcanized and unvulcanized compounds; however, liners
of this rubber are generally based on unvulcanized compounds containing at
least 45% of the rubber. They are available in sheeting of 30 to 45 mil thick-
nesses; most are made with fabric reinforcement of either nylon or polyester
scrim. Liners of this rubber have good puncture resistance, are easy to seam
in the factory or field with solvents, cements, or heat, and have excellent
resistance to weathering, aging, oil, and bacteria. Membranes of this ma-
terial have been used in the lining of pits and ponds where highly acid-con-
taminated fluids are encountered.
After polyvinyl chloride, this is the most used polymeric material for
liners.
Elasticized Polyolefin
Membrane liners of an elasticized polyolefin have been recently intro-
duced. This material is unvulcanized and thermoplastic and can be easily
33
-------
seamed with heat either in the field or factory. It features excellent resis-
tance to weathering and oils. Films of this material are supplied in 20-foot
widths in 20 to 30 mil thickness.
Ethylene-Propylene Rubber (EPDM)
This synthetic rubber is a terpolymer of ethylene, propylene, and a small
amount of a diene monomer that introduces double bonds onto the polymer chain.
These double bonds are sites for vulcanization of the rubber and, as the unsat-
uration is in the side chain of the polymer molecule and not in the main chain,
ozone, chemical, and aging resistance are excellent. The rubber is compatible
with butyl and is often added to butyl to improve resistance of the latter to
oxidation, ozone, and weathering. As it is a wholly hydrocarbon rubber like
butyl, EPDM has excellent resistance to water absorption and permeation, but
has relatively poor resistance to some hydrocarbons. EPDM liners are supplied
in vulcanized sheeting of 20 to 125 mils thicknesses, both supported and un-
supported. Special attention is required in splicing and seaming this ma-
terial, as vulcanizable adhesives must be used.
Neoprene or polychloroprene
Neoprene is a synthetic rubber based primarily on chloroprene. It fea-
tures good weathering and oil resistance and has been used where these prop-
erties are required. It is supplied in vulcanized sheeting of 30 to 125 mils
thicknesses. As it is a vulcanized rubber, vulcanizing cements and adhesives
must be used for seaming.
Polyester Elastomer
This is an experimental thermoplastic rubber which has recently been in-
troduced as a liner material. It has excellent resistance to oils and can be
heat sealed. It is supplied in relatively wide sheets of 7 to 10 mils thick-
nesses.
Polyvinyl Chloride (PVC)
Polymeric membranes based upon PVC are the most widely used flexible lin-
ers. They are available in wide sheets of 10 to 30 mils thicknesses; most is
used as unsupported film, but fabric reinforcement can be incorporated. PVC
compounds contain 30 to 50% of one or more plasticizers to make the films
flexible and rubber-like. They also contain 2% of a chemical stabilizer and
various amounts of fillers. There is a wide choice of plasticizers that can
be used with PVC, depending upon the application and service conditions under
which the PVC compound will be used. PVC polymer generally holds up well in
burial tests; however, plasticized compounds of PVC films have deteriorated
(11,12,13), presumably due to the biodegradability of the plasticizer. Also,
some plasticizers are soluble to a limited extent in water (13). On exposure
to weather with its wind, sunlight, and heat, PVC liner materials can deterio-
ate badly due to loss of plasticizer and to polymer degradation. Consequently,
they are generally covered. Plasticized PVC films are quite resistant to pun-
sture and relatively easy to splice by solvent welding, adhesives and heat.
34
-------
Testing of Polymeric Membranes
Prior to exposure to the wastes, all of the polymeric membranes were sub-
jected to the tests listed in Table 10. Results of these tests are shown in
Table 11. The same tests will be performed on liners after exposure to the
various wastes.
TABLE 10. TESTING OF POLYMERIC MEMBRANE LINERS
Water vapor permeability - ASTM E96.
Thickness.
Tensile strength and elongation at break, ASTM D412.
Hardness, ASTM D2240.
Tear strength, ASTM D624, Die C.
Water absorption or extraction at RT and 70 C, ASTM D570.
Seam strength, in peel and in shear, ASTM D413.
Puncture resistance - Fed. Test Method Std. No. 101B, Method
2065.
Density, ash, extractables.
Of particular interest and probable significance for comparison with re-
sults obtained after long term exposure to wastes, are the results on water
absorption and water vapor permeability which are related properties. Chloro-
sulfonated polyethylene, neoprene, and chlorinated polyethylene exhibited sub-
stantial swelling in water at 70 C, indicating a potential for high swell and
permeability on long-term exposure to water and aqueous solutions. On the
other hand, elasticized polyolefin and polyester elastomer exhibited low lev-
els of swelling. With respect to water vapor permeability, the materials
which exhibited the highest water vapor permeability were PVC and the polyes-
ter elastomer. Butyl and elasticized polyolefin were the lowest.
In seam strengths the vulcanized rubbers, i.e., neoprene, EPDM, and buty],
gave the lowest values. The PVC seamed with cement adhesives, gave peel ad-
hesion values of approximately 15 pounds per inch. The chlorosulfonated poly-
ethylene and the chlorinated polyethylene, which were also seamed with cements,
had peel strengths of 28.5 and 22.5 pounds per inch, respectively. In the
peel adhesion test the specimens of the two heat-sealed materials, elasticized
polyolefin and polyester elastomer, failed at 21 pounds per inch with breaks
in the material, indicating that the true adhesion is higher and that failure
in the seams would not be expected in this type material.
Mounting of Membrane Liner Specimens
All polymeric membrane specimens mounted in the exposure cells have
field-type seams incorporated across the width at the center (Figure 4).
These seams were either made by the supplier or were made by the contractor
35
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37
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in accordance with procedures recommended by the respective suppliers. A de-
scription of the specific seams incorporated in the liner specimens are given
in Table 12.
The polymeric membrane specimens, with the exception of neoprene, were
mounted in the cells with a sealing caulk applied on the upper surface of the
specimen facing the flange of the tank. A gasket of Ht-inch closed-cell neo-
prene sponge was placed between the liner specimen and the flange of the base.
The sponge gasket compensates for irregularities in the two flanges and allows
for a better seal (Figure 1). The neoprene liners were mounted with the same
'j-inch neoprene sponge on the upper side of the liner and no caulk was used.
Two caulking compounds were used in sealing the liners. Since the caulks
are exposed to the waste, they were chosen on the basis of our preliminary
bench tests. We used a butyl caulk with the acid and caustic wastes and a
polysulfide caulk with the other wastes.
After allowing time for the caulk to cure, the cells were tested by fill-
ing with water. A couple of the cells leaked slightly, but could be sealed
by re-tightening the cell flanges to compensate for the compression set taken
by the neoprene foam. One liner had to be completely remounted. One cell
that passed the water test and is filled with waste has developed a slight
seepage between the liner and the exposure cell tank. It may have to be re-
mounted.
38
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39
-------
SECTION 7
SELECTION AND CHARACTERISTICS OF WASTES
Six classes of hazardous wastes were selected for this investigation.
They are:
Acidic sludge
Alkaline sludge
Cyclic hydrocarbon sludge
Lead waste from gasoline tanks
Oil refinery tank bottom waste
Pesticide sludge
Twelve individual wastes were obtained and a preliminary characterization
was made of each. Eleven of these wastes met the classifications and are or
will be included in the exposure tests.
Limited data on each of the individual wastes are given in Table 13.
Both tank bottom wastes were satisfactory for the test; however, neither was
received in adequate quantity to place in the required number of cells and a
third tank bottom waste was collected. It was not satisfactory and a fourth
is now being obtained. It is scheduled for delivery in January 1977.
The wastes were received in 55-gallon drums. Several were found to be
inhomogeneous; as they had separated into two or more phases, to insure uni-
form wastes in the exposure cells, each waste was blended before loading into
the individual cells.
40
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41
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SECTION 8
EXPOSURE TESTS
PRELIMINARY EXPOSURE TESTS
It was recognized at the start that some of the wastes could not be con-
tained by some of the liner materials. For example, wastes containing high
ion concentrations cannot be contained by bentonite and many of the materials
swell badly or dissolve in oily wastes, particularly the asphaltic materials.
Before selecting the combinations of liner materials and wastes to expose,
a series of bench tests was run in which small specimens of the liner materials
were immersed in the various wastes (Figure 11) . For example, 8 different PVC
liners were immersed. They all hardened and shrank in slopwater, but not in
spent caustic; they shrank in saturated oils and swelled in aromatic oils.
Unvulcanized chlorosulfonated polyethylene dissolved in aromatic oils and
swelled badly in the other oily wastes. Cured chlorosulfonated polyethylene
swelled slightly in oily wastes and two varieties of EPDM swelled in oily
wastes. CPE and butyl rubber swelled badly in the oily wastes; neoprene swell-
ed in aromatic oils and hardened in strong acids. The elasticized polyolefin
swelled in the oily wastes and polyester liners swelled slightly. A series
of polyurethanes were found to swell to varying degrees in the oily wastes.
Also included in the preliminary exposure tests were all of the raw materials
which might be used in fabricating the exposure cells and in sealing the lin-
ers in the cells, i.e the epoxy coating and the various caulks and sealants.
The results of these exposure tests which were run for approximately 3
months are presented in Table 14.
Preliminary exposure tests of the modified bentonite-sand mixtures in
contact with the wastes were performed. The test specimens were prepared in
accordance with recommendations of the supplier of Clay A. They consisted of
a mixture of 20% modified bentonite, 80% well-graded sand placed as a 1-inch
deep uncompacted layer in polypropylene beakers having perforated bottoms.
They were then covered with water to hydrate the clay. After 5 days the wa-
ter was removed and the various wastes were poured on (Figure 12). The length
of time for the wastes to pass through the uncompacted sand-clay layers was
recorded (Table 15).
Strong bases and strong acids percolated through both clays in only a few
days. For most of the wastes the percolation times were shorter for Clay A
than for Clay B but, in several cases, once percolation had started, it con-
tinued at a faster rate in Clay B than in Clay A. On the basis of these tests
42
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we dropped the combinations of modified bentonite with the acidic and caustic
wastes for exposure tests in the cells.
Soil and soil cement which had been selected for the study were exposed
to the various wastes by sealing 2-inch diameter cylindrical specimens in one
end of 8-inch long, 54 mm i.d. Pyrex cylinders using Epoxy 1 and Epoxy 4. 3
days after the epoxy cement was cast the cylinders were filled with the wastes
to a depth of 5 inches.
The fine-grain soil specimens (Figure 13) were prepared by molding the
soil at a water content of 20 parts per 100 parts dry soil in a 2-inch diame-
ter mold. The soil was compacted in 5 lifts using a high-frequency impact
tool followed by double-end static compaction. The height of the specimens
was about 2 inches.
The specimen in acidic waste, "16% HNO ", released a few bubbles immedi-
ately, and continued to release bubbles slowly for about a week. Within 1 day
the surface of the specimen developed a flaky appearance and the epoxy peeled
off the glass in both "16 % HNO " and "spent caustic"; within 2 days the same
effect was noted with the specimen in "slopwater".
When probed with a glass rod after 7 days of exposure, the specimen ex-
posed to "slopwater" had a hard surface; the specimen exposed to "spent cau-
stic" was soft on the surface, and the surface of the specimen exposed to
"16% HNO " became flaky. There was no leakage from any of the specimens. Af-
ter 11 days of exposure a slightly damp spot appeared at the center of the
bottom of the specimen exposed to "spent caustic". After 16 days the damp
spot remained unchanged and was neutral to litmus.
The soil cement specimens were molded in a 2-inch diameter mold, with
compaction in 5 lifts using a high-frequency impact tool, followed by double-
end static compaction, of the following compositions:
"Wastes fines" from rock crushing 100 100
Portland cement 10 —
Rice hull ash cement — 10
Water 12 12
Three specimens of each, approximately 2 inches high, were fastened into
1 end of Pyrex cylinders. All specimens had been kept moist for 3 weeks to
cure. 3 days after the epoxy cement was cast, the cylinders were filled to a
depth of 5 inches with "spent caustic", "slopwater", and "16% HNO ", respec-
tively. "16% HNO3" released a few bubbles from both specimens.
After 1 day, "16% HNO," had caused the epoxy to peel off the glass in the
thin layer exposed above the specimens, and a surface layer of soil cement had
flaked off slightly on the rice hull ash cement specimen and a little more on
the portland cement specimen. A few bubbles continued to form. The specimens
exposed to "spent caustic" and "slopwater" appeared unchanged. Concrete based
on the rice hull ash cement has been reported to have acid resistance.
48
-------
Is
-------
After 2 days some liquid began to seep through the RHA cement specimen ex-
posed to "spent caustic". The thin layer of epoxy peeled off the glass in the
cylinders filled with "slopwater", but there was no visible change in the spec-
imens. A few bubbles continued to form in the specimens exposed to "16% HNO ".
After 1 week the appearance of all was substantially the same as above.
Probing with a glass rod showed the surface of the specimens exposed to "16%
HNO " had softened, while the surfaces of those exposed to "spent caustic" and
"slopwater" were sound. The RHA cement specimen exposed to "spent caustic"
continued to leak. The effluent was basic to litmus.
After 2 weeks all appeared substantially the same as above.
The final selection of combinations of liners and wastes was made so that
there would be reasonable chance of a long exposure without a failure. For ex-
ample, liners based on asphaltic materials were not selected for confining
oily wastes; neither were clays used to confine strong caustic or acidic
wastes. When a polymeric liner swelled badly in aromatic waste, that combina-
tion was deleted. The final combinations of liners and wastes which were se-
lected for exposure tests, both in the primary exposure cells and in open tubs,
are shown in Table 16.
The exposure tests in the primary cells have been initiated and will re-
quire at least a year before results are available.
FILLING OF EXPOSURE CELLS WITH WASTES
When the exposure cells were loaded with wastes, only 5 of the 6 types of
wastes were available in sufficient quantities, i.e. 200 gallons or 4 drums,
to fill the desired number of cells:
Lead wastes (by blending 3 different wastes)
Pesticide
Saturated and unsaturated oils
Strong acid
Strong base
There was only one drum of the tank bottom waste containing aromatic oils and
this was insufficient quantity. Furthermore, the oil content of this waste
was extremely low; the original samples had apparently been taken from the top
of the drum. Additional waste of this general type is being obtained.
All of the wastes were received in closed 55-gallon drums and were much
lower in viscosity than had been anticipated. It was originally expected that
they would be sludge-like and could be handled with buckets from open-top
drums. Furthermore, some were found to be very inhomogeneous, consisting of
2 liquid phases and particulate solids. Since the waste of a given type
should have the same composition in all the cells in which it is placed, it
was decided that each waste should be thoroughly mixed and blended before
being added to the cells. It was also decided to pump the wastes from drum to
50
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drum and into the individual exposure cells, thus reducing the chances for
spillage. The equipment which was set up to mix and pump these wastes is
shown in Figure 14.
It was necessary to obtain a pump which was compatible with the wastes,
self-priming, able to pump solids in suspension, and had sufficient capacity
to transfer the contents of a 55-gallon drum in 10 minutes. A flexible impel-
ler pump was obtained having an epoxy pump body and a totally enclosed motor
which allowed hosing down of the pump without getting water into the motor.
The rated capacity was 7 gallons per minute. Both the impeller and the pump
body were replaceable in the event either was damaged by the wastes.
The plan for the mixing and blending of each waste was:
1. To mix thoroughly the contents of each drum by pumping them into
an open-top drum equipped with a 1750 rpm mixer with dual propellers
and mixing with the remaining solids flushed from the original 55-
gallon drum.
2. To transfer \ of the contents to each of 4 additional open-top
drums for blending.
3. To accumulate the mixed quantities in the open-top blending
drums and mix each drum thoroughly.
4. To pump the wastes from the open-top blending drums into the in-
dividual cells.
Thus, each exposure cell could receive an aliquot of the waste of the same com-
position as that received by every other cell containing that waste.
The wastes were loaded in the cells in the order of anticipated increas-
ing difficulty, based on viscosity and the apparent amount of solids. The
"pesticide" having the consistency of water was processed first without prob-
lems using the flexible impeller pump.
The "spent caustic" appeared to be the next easiest waste to handle, as
it was less corrosive than the strong acid ("HNO ") waste and appeared to be
an aqueous solution. However, before 2 drums of caustic had been mixed and
transferred, undissolved salts wore away the epoxy body and face-plate of the
pump which ceased to operate. To solve this problem a second pump, a centrif-
ugal type of 20 gallons per minute, was obtained. The impeller and housing
are made of cast iron which is more resistant to the abrasion of the salts in
the caustic waste than was the epoxy body of the first pump. Furthermore, the
centrifugal pumping action does not depend upon close fitting parts and will
handle particles up to 3/8 inch in diameter.
A strainer was placed over the end of the inlet pipe to strain large par-
ticles when transferring from the closed-head drum. These large particles
were eventually broken-up manually to a pumpable size, and flushed out of the
drum. The shearing action of the mixer in the open-head drum further disinte-
grated these insoluble salts.
52
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To fill the 5-gallon individual exposure cells using the 20 gpm contrifu-
gal pump, it was necessary to reduce the flow by putting a "T" in the system
and circulating a portion of the waste. This pumping system worked very well
with the caustic waste.
There was an insufficient amount of a single lead waste for filling the
primary exposure cells; consequently, the 3 different lead wastes which were
available were combined by the mixing and blending process described above to
yield the 4 drums needed to fill the exposure cells. The centrifugal pump was
used in the mixing, blending, and transferring of the lead wastes.
The saturated and unsaturated oil waste was viscous and had to be pumped
with the flexible impeller pump. Pumping and blending this oily waste was
speeded slightly by warming it with a mantle drum heater.
As the flexible impeller pump is resistant to acids, it was used to pump
the "HNO" waste. The acid would have attacked the cast iron of the centrifu-
gal pump, changing both the character of the waste and of the pump.
54
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SECTION 9
OUTDOOR WEATHERING TESTS OF MEMBRANE LINERS
The primary objective in this study is to determine the effects of expos-
ure of various liner materials to hazardous wastes. The major effort of the
project is to expose the various liners to the wastes in cells under 1 foot
of various wastes to simulate a liner at the bottom of a pit or a pond.
In many actual installations, however, liners are simultaneously exposed
to weather, such as on the berm around a pit, as well as to fluid being im-
pounded. Under such situations liners are exposed to ultraviolet and heat of
the sun, to wind, to ozone, to variations in temperature, and to rain. These
conditions can cause many organic and polymeric materials to degrade, result-
ing in softening or hardening and possibly in breaking.
Liners which are sensitive to these conditions are covered to avoid the
adverse effects of weather. In this project it is desirable to know the full
characteristics of liners, including some of their basic limitations. Con-
sequently, weather exposure tests have been included in the program though
this type of testing is limited.
Two types of outdoor exposure have been undertaken, both of which involvs
exposing specimens on the laboratory roof. In the first type, small speci-
mens of polymeric membranes are being exposed on a rack placed at a 45 angle
to the south. Three 6 inch by 6 inch specimens of each of 11 polymeric mem-
branes are being exposed (Figure 15). Included are the following materials:
Butyl rubber, fabric reinforced
Chlorinated polyethylene
Chlorosulfonated polyethylene, fabric reinforced
Elasticized polyolefin
Ethylene propylene rubber (2 liners)
Neoprene (2 liners)
Polyester elastomer
Polyvinyl chloride (2 liners)
During the exposure we expect to determine:
- Weight loss incurred
- Dimensional changes
- Surface changes including cracking and checking
- Changes in properties such as hardness, tensile,
puncture resistance, and brittleness.
55
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In the second type of outdoor exposure test small open tubs have been
lined with the various polymeric membranes and partially filled with hazardous
wastes. These liner specimens are 4 feet by 4 feet and have been folded over
the edges and corners of the tubs. Each tub has been covered with chicken
wire (Figure 16) to prevent bird bathing. A seam has been incorporated in each
of the liners except the polyester elastomer. (The supply of liners with seams
which had been received from the manufacturer was exhausted. The material re-
quires special heat sealing conditions which were not available.)
The combinations of liners and wastes which were selected for this test
are shown in Table 16. The cells are approximately half filled with wastes;
the levels of the wastes in the tubs are allowed to change within limits due
to evaporation and rain. The cells can be covered if there is too much rain;
if there is excessive evaporation, water is added.
These tubs will be left exposed during the remainder of the project, ex-
cept in case of failure of a liner. During exposure the overall effects on the
liners will be observed, such as swell and cracking, particularly at folds and
corners; also, it will be observed if there is any opening of the seams. At
the end of the exposure period, when the tubs are emptied and the liners re-
trieved, the physical properties of the membranes and the seams at various po-
sitions will be determined.
57
-------
Ssj |
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REFERENCES
1. U.S. Environmental Protection Agency. Report to Congress on Hazardous
Waste Disposal, June 30, 1973.
2. Dallaire, Gene. Tougher Pollution Laws Spur Use of Impermeable Liners.
Civil Engineering, ASCE, May 1975. p 63.
3. Geswein, Allen J. Liners for Land Disposal Sites - An Assessment. EPA-
530/SW-137, U.S. Environmental Protection Agency, Washington, D. C.,
March 1975. 66 pp.
4. Haxo, H. E. Assessing Synthetic and Admixed Materials for Lining Land-
fills. In: Proceedings of Gas and Leachate from Landfills: Formulation,
Collection and Treatment Symposium, U.S. Environmental Protection Agency,
Rutgers University, March 1975, EPA 600/9-76-004. pp.130-158.
5. Haxo, H.E. Evaluation of Selected Liners Exposed to Hazardous Wastes.
In: Proceedings of Hazardous Waste Research Symposium, Tucson, Arizona,
EPA-600/9-76-015, 1976.
6. Lee, Jack. Selecting Membrane Pond Liners. Pollution Engineering, 1974.
7. Stewart, W.S. State-of-the-Art Study of Landfill Impoundment Techniques.
EPA Project R-803585, May 31, 1975.
8. Haxo, H.E. and R.M. White. First Interim Report, Evaluation of Liner Ma-
terials Exposed to Leachate, Contract 68-03-2134, November 27, 1974.
9. Haxo, H. E., and R.M. White. Second Interim Report, Evaluation of Liner
Materials Exposed to Leachate, EPA-600/2-76-255, September 1976.
10. Vallerga, B.A., and R. G. Hicks. Water Permeability of Asphalt Concrete
Specimens Using Back-Pressure Saturation. J. Materials 3 (1) 1968. pp
73-86.
11. Wendt, T.M., A.M. Kaplan, and M. Greenberger, "Weight Loss as a Method for
Estimating the Microbial Deterioration of PVC Film in Soil Burial", Int.
Biodetn Bull., 6 (4), 139-143, (1970).
12. Scullin, J.P., M.D. Dudarevitch, and A. I. Lowell, "Biocides" in "Encyclo-
pedia of Polymer Science and Technology", Vol. 2, p 379, (1965).
13. Sarvetnick, H.A., "Polyvinyl Chloride", Van Nostrand Reinhold Co. (N.Y.)
(1969) .
59
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APPENDIX A
MATERIALS USED IN CONSTRUCTING EXPOSURE CELLS AND MOUNTING LINER SPECIMENS
Material
Use
Trade Name
Supplier
Epoxy Resins;
Epoxy 1
Epoxy 2
Epoxy 3
Epoxy 4
Paints;
Primer
Caulks;
Butyl rubber
Polysulfide
Gasket;
Neoprene sponge
Silica gravel
Sandblasting sand
To cast epoxy rings Concresive 1217
to seal liners
cells.
To coat inner walls Concresive 1305
of cells and bases
and to cast sealing
rings.
To cast epoxy rings Concresive 1310
To seal 2 in. cyl-
indrical specimen
in glass cylinder.
Coating of inner
surfaces of cells.
Seal membrane spec-
imens in cells.
Seal membrane spec-
imens in cells.
Concresive 1001
Koropon CA
Sure-Seal
Colma Joint Seal-
er (Sikaflex 412)
To seal liners in
primary exposure
cells.
Inert gravel in
bases of cells .
Used in epoxy cast Clementina No.2
rings and on inside
surfaces of spacers.
Adhesive En-
gineering
Adhesive En-
gineering
Adhesive En-
gineering
Adhesive En
gineering
De Soto,
Berkeley,CA
Carlisle
Sika, Lynd-
hurst, N.J.
Cal Neva,
Oakland, CA
G.E. Dodson
Auburn, CA
Clementina
Berkeley,CA
The first rings were made with Epoxy 1; however, as Epoxy 2 and 3 are more
resistant to chemicals and solvents, we changed to them.
60
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APPENDIX B
MAJOR EQUIPMENT
Paint sprayers:
Binks Model 69 - general purpose standard production sprayer.
Binks80-210 Quart pressure cup with air regulator.
Binks 66 by 66 SD nozzle with 565 needle (for primer).
Binks 68 by 68 PB nozzle (for epoxy coating).
Air compressor (rented).
Mixers:
h HP, Model D14 - 1750 rpm, MixMor, Inc., with two 3-inch propellers.
Pumps:
Centrifugal Pump - Teel, Model 3P577A, Dayton Electric
Flexible Impeller Self-Priming Pump, Flotec Model F4P1-1104 - Flotec,
Inc. (Neoprene impeller and epoxy body), 1/3 HP, 115V, 1725 rpm.
Soil Shredder:
Model 2-E, W-W Grinder Corp.
61
-------
APPENDIX C
MATERIALS FOR ADMIX LINERS
Material
Supplier
Soils:
Fine-grain, high silica content
Soil cement:
Soil: "Wastes fines" from rock crushing
Cement: Type 1-2-5 Portland cement
Rice hull ash (RHA) cement
Coating C: Coal tar epoxy, Ceilcote
Flake Prime and Flake Tar
Coating K: Coal tar epoxy, Bitumastic
3COM
Hydraulic asphalt concrete (HAC):
Hot mix
Aggregate, dense-graded % inch maximum
Asphalt, AR-4000
Modified bentonite:
Sand, dense-grade No. 2 (contained
1% water)
Mare Island Naval Shipyard,
Vallejo, CA.
Quarry Products Company,
Richmond, CA.
Kaiser Permanente
Industrial Materials Co.,
Los Angeles, CA.
Ceilcote
Koppers
Ransome Company, Emeryville,
CA.
Lone Star Quarry, Livermore,
CA.
Douglas Oil Company
Topsoil King, Richmond, CA.
62
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-77-081
2.
3. RECIPIENT'S ACCESSIOI*NO.
4. TITLE AND SUBTITLE
LINER MATERIALS EXPOSED TO
HAZARDOUS AND TOXIC SLUDGES
First Interim Report
7. AUTHOR(S)
Henry E. Haxo, Jr., Robert S. Haxo, Richard M. White
5. REPORT DATE
June 1977 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Matrecon, Inc.
2811 Adeline Street
Oakland, California 94608
10. PROGRAM ELEMENT NO.
1DC618
11. CONTRACT/GRANT NO.
68-03-2173
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory--Cin.,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Interim 3/75 - 10/76
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
16.ABSTRACT jne storage and disposal of hazardous liquids ana solid wastes on tne land
are increasing the potential for pollution of surface and ground waters by these
wastes or their leachates. Intercepting and controlling the seepage of such fluids
by the use of impervious barriers offers a promising means of reducing or eliminating
such pollution. This engineering research project was undertaken to assess the rela-
tive effectiveness and durability of a wide variety of liner materials when exposed to
hazardous wastes. The materials under study include a native soil, modified bentonite
a soil cement, a hydraulic asphalt concrete, an asphaltic membrane, and 8 polymeric
membranes based upon polyvinyl chloride, chlorinated polyethylene, chlorosulfonated
polyethylene, ethylene propylene rubber, neoprene, butyl rubber, an elasticized poly-
olefin, and a thermoplastic polyester elastomer, respectively. In this study the
liner materials are exposed to such hazardous wastes as a strong acid, a strong base
an oil refinery tank bottom waste, a blend of lead wastes from gasoline production a
saturated and unsaturated hydrocarbon oil waste, and a pesticide. The experimental
approach and methodology followed are described and results of prel minary tests u ed
in the selection of materials for extensive testing are presented
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Linings, Leaching, Hazardous Materials,
Sludge, Pollution, Plaster
Solid Waste Management
Hazardous Wastes
13B
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSTFTFD
21. NO. OF PAGES
73
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
63
,vU S GOVERNMENT PRINTING OFFICE. 1977-757-056/61427 Region No. 5-n
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