United States
Environmental Protection
Agency
Muniopel Environmental Research
L^x>ratorv
Cincinnati OH 45268
EPA 600 2-79-136
August 1979
Research and Development
Flue Gas Cleaning
Sludge Leachate/
Liner Compatibility
Investigation
Interim Report
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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 perforrned 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-600/2-79-136
August 1979
FLUE GAS CLEANING
SLUDGE LEACHATE/LINER COMPATIBILITY INVESTIGATION:
Interim Report
by
Clarence R. Styron III
Zelma B. Fry, Jr.
Geotechnical Laboratory
U. S. Army Engineer Waterways Experiment Station
Vicksburg, Mississippi 39180
Interagency Agreement No. EPA-IAG-D5-0785
Project Officer
Robert E. Landreth
Solid and Hazardous Waste Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio U5268
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 and the U. S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U. S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation 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 people. Noxious air, foul water, and spoiled
land are tragic testimony to the deterioration of the 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 solu-
tion, 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 pollution
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 communication
link between the research and the user community.
This is an interim report presenting the results of physical tests and
analyses of materials tested as liners for industrial waste. The tests
followed 12 months inundation in actual wastes to simulated depths of 30 ft.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
111
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ABSTRACT
This project was initiated to study the effects of two industrial waste
materials on 18 items used to contain these wastes. Seventy-two test cells,
1 ft in diameter and 2 ft high, were fabricated. Ten items were mixed with
a clayey silt and compacted in the bottom 6 in. of the test cell; six spray-
on and two prefabricated membrane items were placed over 6 in. of compacted
soil. Four gallons of sludge were added to each test cell and enough tap
water to bring the liquid to within k in. of the top of the test cell. Each
test cell was covered and pressurized to simulate 30 ft of head.
This report lists and discusses the data following 12 months of inunda-
tion of each item with both sludges. Portland cement, cement plus lime, and
C^OO when mixed with the soil resulted in a significant reduction in per-
meability.
This report was submitted in partial fulfillment of the Interagency
Agreement "FGD Waste Leachate/Liner Compatability Studies" IAG-D5/6-0785
between the U. S. Environmental Protection Agency (EPA) and the U. S. Army
Engineer Waterways Experiment Station (WES). This report covers the period
from April 15, 1975, through September 30, 1977- A subsequent report will
include a 2^-month data series and cost data where appropriate.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures vii
Tables ix
Abbreviations and Symbols • x
Metric Units of Measure xii
Acknowledgements xiii
1. Introduction and Objectives 1
2. Summary 3
3. Approach and Research Plan h
k. Design and Construction of Test Cells
and Ancillary Equipment 6
General Considerations for Design 6
Test Cell Construction 9
Ancillary Equipment 9
5- Selection and Characteristics of FGD Sludge 13
Selection 13
Characteristics 1^
6. Selection and Properties of Soil Materials, and Liners .... 18
Selected Soil Materials 18
Soil Permeabilities 21
Liner Selection and Testing 22
Selected Liner Materials 23
7. Preparation and Installation of Liner
and Sludge Materials on Test Cells 31
General Procedures 31
Compaction Devices and Methods 31
Liner Preparation 31
Sealant 33
FGD Sludge 33
Chemical Analysis Data Base 33
Completion of Assembly 37
Identification System 37
8. Test Data 38
Admix Liner Materials 38
Spray-on and Prefabricated Membrane Liners 39
Permeability 39
Filterability 1*3
9. Analysis and Discussion of Results 50
Physical Tests 50
Chemical Tests 52
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References 58
Appendix
A. Manufacturer/Address for the Selected Liner
Materials 60
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FIGURES
Number Page
1 Pettibone mixer ....................... 7
2- UC and grab test equipment ................. 8
3 Schematic of a test cell section with a spray-on or
membrane liner depicted and ancillary equipment ..... 10
k Exploded view of a typical test cell ............ 11
5 Assembled test cell ..................... 11
6 Assembled test cells on racks in holding area ........ 12
7 Gradation curves for soil materials ............. 19
8 Moisture-density curves for test soils ............ 20
9 Pinhole test device for membrane liners ........... 2k
10 AC^O curing in a plastic mold ................ 30
11 The Instron machine with both compaction footings ...... 32
12 Typical operation using Instron machine and k. 5-in.-diam
footing to compact soil layer in a test cell ....... 32
13 Portable mixer with extended mixing blades
ik Soil being removed from bottom of test cell lined
with TACSS 025 ...................... 38
15 Admix liner materials following 12 months of
inundation and unconfined compression test ........ Uo
l6 Asphaltic concrete liner surface showing extreme
cracking ......................... 51
17 Asphaltic concrete liner with sludge removed,
approximately 1 in. water added, and 2-psi
back pressure applied .................. 51
VI1
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Number Page
18 Close-up of cracks in asphalt ic concrete liner.
Discolored area around periphery indicates area
covered by silicone sealant ................ 52
19 Spray-on liner materials samples following
12 months of inundation and grab test ........... 53
20 Prefabricated membrane total liner material samples
following 12 months of inundation and grab test ...... 5^
21 Pattern of leakage from membrane ruptures .......... 55
Vlll
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TABLES
Number Page
1 Chemical Analysis Parameters and Test Methods 13
2 Chemical Analysis of Sludge and EPA Allowable Limits. ... 15
3 SLT and TCA Permeability Values 21
k Selected Liner Materials 25
5 Physical Tests - Admix Liners 28
6 Physical Tests - Spray-on and Membrane Liners 30
7 Chemical Analysis Data 35
8 Physical Tests - Admix Liners kl
9 Physical Tests - Spray-on and Membrane Liners k2
10 Summary of Chemical Analysis Data kk
11 Summary of Chemical Analysis Data k6
12 Specific Conductance and pH Values kQ
13 Liner Materials on Silty Sand Listed in Order of
Increasing Chloride Content 56
Ik Liner Materials on Clayey Silt Listed in Order of
Increasing Chloride Content 57
ix
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LIST OF ABBREVIATIONS AND SYMBOLS
ABBREVIATIONS
avg
°C
cm/sec
cu ft
diam
EPA
Op
FGD
ft
gal
Gs
hp
in.
Ib/cu ft
mg/1
ML
OD
pz
oz/sq yd
ppm
psi
psig
PVC
SM
SLT
TCA
UC
uses
WES
SYMBOLS
A
As
B
Be
Cd
Cn
Cr
Cl
Cu
American Society for Testing and Materials
averages
degrees Celsius
centimeters per second
cubic feet
diameter
Environmental Protection Agency
degrees Fahrenheit
flue gas desulfurization
foot/feet
gallon(s)
specific gravity
horsepower
inch
pounds per cubic foot
miligrams per liter
clayey silt
outside diameter
ounces
ounces per sq yd
parts per million
pounds per square inch
pounds per square inch gage
polyvinyl chloride
silty sand
standard laboratory techniques
test cell apparatus
unconfined compression
Unified Soil Classification System
Waterways Experiment Station
area
Arsenic
Boron
Beryllium
Cadmium
Cyanide
Chromium
Chloride
Copper
x
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D — diameter
H ~ height
Hg — Mercury
i — average hydraulic gradient during t
Mg — Magnesium
Mn — Manganese
Ni — Nickel
NC>2, N — Nitrogen Nitrite
NOj, N — Nitrogen Nitrate
Pb — Lead
Q — quantity of leachate collected
Se — Selenium
S03 — Sulfite
S(% — Sulfate
t — time period during collection of leakage
V — Vanadium
Zn — Zinc
AH — change in height
xi
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METRIC UNITS OF MEASURE
Multiply
By
To Obtain
cubic feet 0.028317
Fahrenheit degrees* 5/9
feet 0.30U8
gallons (U. S. liquid) 3.785^12
gallons per square yard U.5273
inches 25.it
mils 0.02514.
ounces (U. S. fluid) 29=57353
ounces (mass) per square 33.90575
yard
poises (absolute viscosity) 0.1000
pounds (mass) O.U53592U
pounds (force) per square 689^.757
inch
pounds (mass) per cubic foot l6.0l8ll-6
pounds (mass) per gallon 119.826
(U. S. liquid)
tons (2000 lb, mass per 0.22^17
acre)
meters
Celsius degrees or
Kelvins*
meters
cubic decimeters
cubic decimeters per
square meter
millimeters
millimeters
cubic centimeters
grams per square meter
pascal seconds
kilograms
pascals
kilograms per cubic meter
kilograms per cubic meter
kilograms per square meter
* To obtain Celsius (C) temperature readings from Fahrenheit (F) readings,
use the following formula: C = (5/9)(F - 32). To obtain Kelvin (K)
readings, use: K = (5/9)(F - 32) + 273.15.
Xll
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ACKNOWLEDGMENTS
The cooperation of Drs. Larry W. Jones and Philip G. Malone, Environ-
mental Laboratory, WES, in providing an analysis and discussion of the chem-
ical analysis, respectively, is gratefully appreciated.
Special thanks are also directed to Mr. Gerald T. Easley, Geotechnical
Laboratory, WES, vho designed the test cell and ancillary equipment and
supervised all procurement and fabrication.
The authors wish to thank Messrs. Robert E. Landreth and Herbert B.
Schomaker for their support and guidance during this phase of the subject
project.
xiii
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SECTION 1
INTRODUCTION AND OBJECTIVES
The industrialization of this country has had a very significant impact
on the environment. Many industries produce wastes that may be highly toxic
to the environment if proper controls are not used. As the volumes of these
wastes increase, disposal problems are multiplied both in availability of
land space and economics dictating development of new disposal technology.
The Environmental Protection Agency's "Report to Congress on Hazardous Waste
Disposal" in 1973 (l) concluded that the then existing management of hazard-
ous wastes was generally inadequate and that the public health and welfare
are now threatened by the uncontrolled disposal of such waste materials into
the environment.
The potential environmental impact is the contamination of ground and
surface waters, which can occur from improperly located, designed, or
operated disposal sites. The potential exists because within a disposal site
various physical, chemical, and biological processes occur from water or
fluid percolating through the wastes, resulting in a leachate potentially
hazardous to contamination of the groundwater. Controlling the leachate by
lining the disposal area with an impervious material could be a solution to
the problem, and it would allow the utilization of more sites for disposal
areas. The use of liners for such purposes is not a new concept. However,
there is a lack of knowledge concerning the compatibility of liner materials
subjected to certain toxic wastes and particularly the life expectancy of
the liners. In this respect, the Environmental Protection Agency (EPA) needs
considerably more information in order to supply guidance and possible future
regulation for use of liners for waste disposal areas.
' This study was undertaken with the following objectives:
a. To determine the compatibility of liner materials with flue gas
desulfurization (FGD) sludges and associated liquors and leachates.
b. To estimate the length of life for the liners.
c. To assess the economics involved with the purchase and placement (to
include construction) of various liner materials.
To realize the study objectives, the liner materials were subjected to a
simulated 30-ft* head (depth) of sludge, as would be expected in disposal
ponds.
*A table for converting U.S. customary units of measure to metric (Si) units
is given on page xii.
1
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This interim report describes the following procedures:
a. The methodology and research approach.
b. The construction of the test cells and ancillary equipment.
c. The selection of the various liners and wastes (sludges).
d. The preparation of the liners and sludges and installation in the
test cells.
e. Physical properties of the liners and chemical analyses of the
sludges and leachates for zero time (unexposed) and for a 12-month
exposure period.
The final report will present the results after the liners have been
exposed toi-the sludges for a 214-month exposure period, along with estimates
of liner life and an economic assessment of the various liners.
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SECTION 2
SUMMARY
A total of 72 special test cells were constructed to study the compati-
bility of 18 liner materials and two selected FGD sludges. Devices were
installed to collect the leachate from each test cell for quantity of leakage
determination, rate of leakage determination (permeability), and storage for
subsequent chemical analysis. The test cells were pressurized to simulate a
disposal area approximately 30 ft deep. Physical tests of the 18 liner
materials were conducted before exposure to the FGD sludges and again after
12 months exposure. These same tests will be conducted after 2k months
exposure.
Five of the admix liner materials, which were Portland cement, lime,
Portland plus lime, CHOO, and CST, were tested in unconfined compression (UC)
following 12 months exposure to both sludges, and the UC values were approxi-
mately double the zero time (control) values. .The asphaltic concrete liner
exhibited extensive cracks whereas TACSS 020 and 025 suffered decreases in
UC. Guartec UF and M179 proved incompatible with either sludge type and the
testing of these two products was discontinued. The breaking strength of the
s-pray-on and membrane liners decreased without exception. The percent elon-
gation varied, increasing significantly for total liner, decreasing for
DCA-1295 and Aerospray 70, and remaining essentially constant for Tl6,
Dynatech, and Uniroyal. Since the AC^O liners could not be tested in this
manner and only one Sucoat liner could be tested, evaluation of these liners
will not be made until the 2U-month data are received.
To determine the concentration of 20 heavy metals, chemical tests were
conducted on the two FGD sludges as received and on the FGD sludge liquor
that passed through the lined test cells, and the data were tabulated.
Increasing concentrations of some of the heavy metals were indicative of
liner breakdown and/or penetration by the sludge material in the case of
Guartec UF and two TACSS materials. The chloride concentration of the liquor
collected beneath each test cell is presented separately as an indication of
how the sludge liquor moves through the liner/soil combination. For example,
these data indicate that the AC^O and Sucoat both had liquor moving through
the entire cross section of the liner. It is expected that should liquor
continue to pass through these or similar liner materials in a real situation,
the discharge from the test cells would approach the composition of the
sludge liquor.
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SECTION 3
APPROACH AND RESEARCH PLAN
To meet the objectives of this study, the overall experimental approach
•was to expose specimens of a variety of potential liner materials to selected
FGD sludge wastes over a period of time under conditions that simulate dis-
posal areas and to determine changes in the physical properties of the liner
material with exposure time.
Due to the type of material to be disposed, the volume, and related eco-
nomic considerations, the selection of potential liner candidates was ini-
tially limited to those that were relatively inexpensive. However, ease of
placement and construction costs were also considered in selection criteria as
a possible offset to high material costs. Primary consideration was placed
on the use of admixed or stabilized in situ material; secondly, use of spray-
on materials; and finally, limited use of prefabricated membrane-type
materials. The membrane- or polymeric-type liners are being tested exten-
sively in other EPA-supported projects (2-h). From the above categories, the
requirement was to select a total of 18 liner materials to consist of ten
admix, six spray-on, and two membrane types for inclusion in the study. Two
FGD sludges were selected for the study.
Specifically, the plan has been
a. To select liner materials that have the potential for being used as
liners for FGD sludge disposal areas.
b. To design and construct test cells simulating the conditions under
which liner materials would exist in a disposal area. The test cells
are to be capable of simulating a depth of sludge of at least 30 ft
that can be applied in increments over a period of time.
c. To select the FGD sludge that would be representative of those
expected to be encountered in disposal areas.
d. To characterize the FGD sludge so that behavior of selected liners
can be predicted for required exposure periods.
e. To expose the liner materials for 12- and 2k-month periods.
f. To subject the liner materials to physical tests to determine the
characteristics of the liners at each of the data points (i.e. zero,
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12, and 2H months) to provide three data points regarding behavior
over a period of time.
g. To collect and measure the quality of permeate, if any, of the
sludge leachate through the liners.
h. To analyze the permeate of the 12- and 2^-month periods for the
20 parameters used to indicate water quality. The analyses will be
conducted at a sensitivity equal to that obtainable by flame AA
spectrophotometry.
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SECTION U
DESIGN AND CONSTRUCTION OF TEST CELLS
AND ANCILLARY EQUIPMENT
The considerations for design of the test cells and the special equip-
ment and materials required are discussed in this section.
GENERAL CONSIDERATIONS FOR DESIGN
Several factors were considered for the design of the test cells. These
factors included the methods for constructing or installing liners for field
installations (5), the size or amount of a specimen required for physical
tests at the termination of exposure periods, a cell of sufficient volume to
contain the liner and sludge, and a means of simulating a 30-ft depth of
sludge.
The admix liners constitute the largest number of liners selected for
this study. Admix materials are usually chemicals added to a road base or
runway base soil in small quantities (normally U to 10 percent of the dry
soil weight) to improve some particular physical quality(ies) of the soil.
They can be mixed at the site by covering the area to be treated with the
chosen amount of additive and then mixing it with the underlying soil using
a mixing device such as the Pettibone mixer (Figure l). This machine, along
with other machines such as the road grader and dozer, is used to process and
move large quantities of soil economically. Due to the size of these
machines and the normally undulating terrain, 6 in. is judged to be the mini-
mum practicable depth to stabilize. This is believed true even when the
admix material is mixed with the soil at a batch plant and transported to the
site for spreading and compacting.
Spray-on materials should be applied to "level" areas or at least areas
free of vertical or nearly vertical surfaces (i.e. wheel ruts). Usually some
work is required to ready a site before a spray-on material can be applied.
Ideally all vegetation, sticks, roots, and large rocks are removed, and the
area rolled and prewet before the spray-on is applied.
Both spray-on materials and membranes require some protection against
differential soil settlement. Membranes are simply left wrinkled with the
idea that enough slack will be available to keep any resulting differential
soil settlement from rupturing the membrane. Differential soil movement can
easily rupture spray-on materials, rendering the liner ineffective.
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Figure 1. Pettibone mixer.
The best method for limiting differential soil movement is through com-
paction of the soil prior to placement of the spray-on material. From a
practical standpoint, the minimum depth of compaction should be 6 in. Thus,
it was decided that the liners would be tested with 6 in. of compacted soil
in each case. In the admix materials, the liner is mixed with the compacted
soil to a depth of 6 in., whereas the spray-on and membrane liners cover
6 in. of compacted soil. Any leachate would be forced to permeate a liner
material and 6 in. of compacted soil, thus assuring comparable conditions.
The size of each liner specimen was determined by the number and type
of tests following the exposure period. Nondestructive-type tests could only
be used to detect swelling, shrinking, or obvious deterioration. Destructive-
type tests were required to determine changes in liner strength and elastic-
ity. The UC test was selected as a standard for the admix materials, and
the grab test was chosen for the spray-on and membrane liners. Duplicate
specimens were used for each test and the results averaged. Duplicate speci-
mens were also valuable for determining unusual test results and for deter-
mining when additional testing was necessary. The UC test (American Society
for Testing and Materials (ASTM) Method D 2166-66) (6) requires specimens
approximately 1.2 in. in diameter by 2.8 in. high, whereas the grab test
(ASTM D 1682-6U) (T) requires 6- by U-in. specimens. The UC and grab test
equipment is pictured in Figure 2.
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a. Unconfined compression machine
and recorder.
b. Instron machine with grab
test attachments.
Figure 2. UC- and grab test equipment.
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Pressurization was considered to be the most feasible approach to simu-
late a 30-ft depth of sludge. This necessitated an enclosed system and a
pressure source sufficient to supply 20 psi to each test cell. The use of
pressure permitted the use of minimum amounts of other materials, including
sludge. Four gallons of sludge was arbitrarily chosen as a sufficient amount
for a 2-year exposure period.
TEST CELL CONSTRUCTION
Polyvinyl chloride (PVC) was selected for construction of the test cells.
PVC was considered to be an inert material that would not react chemically
with the FGD sludge. Schedule 80 PVC pipe, ID 11-13/16 in. with a pressure
tolerance of 130 psi was selected for the pressure cells. The base, also
PVC, was 2-1/2 in. thick and 15 in. square. The base was tapped at the
center to accommodate the drain port, and a special recess was provided to
house a 6-in.-diam and lA-in.-thick porous plastic disc. The PVC top was
15 in. in diameter and 3/8 in. thick with a tap provided for pressure attach-
ments. The top, flanges, and base were drilled to accommodate 3/8-in. bolts
for connection purposes. A schematic drawing of the test cell with ancillary
equipment is shown in Figure 3. An exploded view of the cell is shown in
Figure U, and an assembled cell is shown in Figure 5. An additional top
plate of lA-in. aluminum was required to prevent buckling of the PVC top
as pressure was increased in the cell.
A total of 72 cells were fabricated. The initial step in assembly was
attachment of the base plate to the cylindrical body. A silicone sealant
was applied at the interface of the flange and base plate and the bolts were
secured. The same procedure was used for the coverplate after installation
of the liner and sludge (the placement of liners and sludge is discussed
elsewhere in this report). After assembly, the cells were placed in a
holding room on racks previously constructed as shown in Figure 6. The
holding room was capable of maintaining a constant temperature of 68°F and
kO percent humidity. In this manner, 18 liner types would be exposed to two
sludge types for 12 months. This would require 36 test cells. A second set
of 36 test cells was assembled at the same time for 2k months exposure.
ANCILLARY EQUIPMENT
The ancillary components consisted of a pressure system for pressuri-
zation of the test cells and a system to collect the leachate.
For the pressure system, a 2-hp compressor was used to supply compressed
air through a piping system to a series of manifolds from which plastic
tubing was used to connect to each individual cell (see Figures 3 and 6).
Regulators and check valves were used between the compressor and manifolds
for control of the desired pressure and as a safety measure against rapid
depressurization should a failure occur. A second compressor was installed
for use as required.
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REGULATOR
AIR
PRESSURE
SI LI CONE SEAL-
LINER TEST
MATERIAL
POROUS DISK
PLASTIC
CONTAINER
LEACHATE
Figure 3. Schematic of a test cell section with a spray-on
or membrane liner depicted and ancillary equipment.
10
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Figure U. Exploded view of a typical test cell.
Figure 5. Assembled test cell,
11
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Figure 6. Assembled test cells on racks in holding area.
12
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SECTION 5
SELECTION AND CHARACTERISTICS
OF PGD SLUDGE
SELECTION
The two FGD sludges used in this study were selected from a group
included in an EPA-supported research project at the WES (8). The group
included FGD sludge from five different power plant locations from which
samples had been previously obtained and characterized by chemical analyses
(Table l). Based on the available information, EPA recommended two sludges,
one from an eastern coal lime-scrubbed process (Sludge A) and one from an
eastern coal limestone-scrubbed process (Sludge B). The sludges were ob-
tained from disposal ponds at the plant sites, placed in metal cans lined
with heavy plastic bags, and transported to WES. The percent solids of
Sludge A is hi.6, and the pH is 10.3; and the percent solids of Sludge B
is 3^.2, and the pH is 9.0.
TABLE 1. CHEMICAL ANALYSIS PARAMETERS AND TEST METHODS
Parameter
Arsenic (As)
Beryllium (Be)
Cadmium (Cd)
Chromium (Cr)
Copper (Cu)
Mercury (Hg)
Magnesium (Mg)
Manganese (Mn)
Nickel (Ni)
Lead (Pb)
Selenium (Se)
Vanadium (V)
Zinc (Zn)
Test Method
Atomic absorption (AA),
gaseous hydride method
Emission spectrophotometer
AA, graphite furnace
AA, graphite furnace
AA, graphite furnace
AA, cold vapor technique
, AA, flame
AA, flame
AA, graphite furnace
AA, graphite furnace
AA, gaseous hydride method
Emission spectrophotometer
AA, graphite furnace
(continued)
13
Limit of Detection
ppm
0.002
0.005
0.001
0.001
0.002
0.0002
0.1
0.01
0.005
0.003
0.003
0.005
0.001
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.TABLE .1 (continued)
Parameter
Test Method
Limit of Detection
ppm
Boron (B)
Chloride (Cl)
Cyanide (Cn)
Nitrite, nitrogen (NO ,N)
Nitrate, nitrogen (NO ,N)
Sulfite (SO ) '
Sulfate (SO, )
Standard methods* - 107B
Standard methods* - 112B
Technicon autoanalyzer
Standard methods* - 13^
Standard methods* - 213E
Standard methods* - 158
Standard methods* - 156C
0.3
8.0
0.005
0.01
0.05
1.0
* Standard Methods for the Examination of Water and Wastewater. 1976.
iHh ed. American Public Health Association. Washington, D. C.
Table 2 shows the concentrations of 20 parameters for Sludges A and B
with the sludge solids listed on the first line and the sludge liquor on the
second line. The last tabulation provides the allowable limits for metal
concentrations from the Journal of Water Technology and Quality 75-76,
Maximum Allowable Domestic Water Supply Criteria (9, 10). As noted, some of
the values are secondary standards (EPA) proposed for drinking water criteria.
CHARACTERISTICS
As can be noted from Table 2, the two FGD sludges are very similar in
composition. Sludge A (lime-scrubber sludge) is generally high in trace
metal content and has higher arsenic, beryllium, chromium, copper, manganese,
nickel, lead, and vanadium than Sludge B. Boron and chloride levels are also
higher in Sludge A than Sludge B. These differences probably reflect dif-
ferences in the chemical composition of the coals burned at the two power
plants. It can also be noted that Sludge B has more magnesium than Sludge A;
this is probably due to the incorporation of dolomite in the limestone feed
used for scrubbing. Lime usually has a lower magnesium content than scrubber
limestone.
With few exceptions, the compositions of the sludge liquors are very
similar. The scrubber liquor from Sample A has over twice the concentration
of manganese than does liquor from Sample B. The scrubber liquor from
Sample B has higher concentrations of copper, boron, cyanide, and sulfate.
-------
TABLE 2. CHEMICAL ANALYSIS OF SLUDGE MD EPA ALLOWABLE LIMITS
Sludge
and EPA
Allowable Lab Arsenic Beryllium Cadmium Chromium Cyanide Copper Mercury
Values Material Symbol As Be Cd Cr Cn Cu He
Sludge A
Sludge B
Sludge
Solids
Sludge
Liquid
Sludge
Solids
mg/kg
mg/£
mg/kg
0.28
0.003
0.16
6.8
0.005
1.25
0.005
0.001
0.007
133.0 — *
0.001 0.012
33.3 — *
0.85
0.009
0.38
O.kk
0.002
O.Bh
Sludge
Liquid mg/S- 0.003 <0.005 <0.001 <0.001 0.018 0.010 0.002
EPA Values mg/1 0.05 O.Ollt 0.01 0.05* 0.005 0.2§ 0.002
obtained
from
Ref. 9 and 10
* — = Insufficient sample to analyze for all parameters.
t Fresh water-aquatic life criteria.
* Freshwater and marine organisms criteria.
§ Secondary standards proposed for drinking water criteria (EPA).
(continued)
-------
TABLE 2 (continued)
o\
Sludge
and EPA
Allowable
Values
~mm*~*^^l~^ilm~mmmi***mmmmmm^^^
Sludge A
Sludge B
EPA
Material
^^^^Vi^M^HH»^MVI^P*IM^^M-M^^
Sludge
Solids
Sludge
Liquids
Sludge
Solids
Sludge
Liquids
Values
obtained
from
Lab
Symbol
mg/kg
mg/A
mg/kg
mg/A
nig/ 2.
Magnesium Manganese
Mg Mn
3030.0 8U.8
10.1 2.3
5160 ITS. T
13.8 0.95
n/a 0.05
Nickel
Ni
••^fcw^p^^— *— ^™«fcMfc— ^— ^
0.8U
<0.003
0.38
0.003
0.1*
Lead
Pb
^M^B^^MWI^"—^^^^^^^
1.08
<0.003
0.68
0.003
0.05
Selenium
Se
^^•^•4W^VI^M«^^^B^H^M--««*«— 1
1.38
<0.003
• 2.15
0.007
0.01
Zinc
Zn
(••••••••^^••^••^•••^•flVMV
135
0.002
278
0.002
5.0t
Sulfite
so3
V^^H^h^««^^^^.^^H^^«-V—l^^^
190
<1.0
200
<1.0
n/a
Ref . 9 and 10
* Freshwater and marine organisms criteria.
t Secondary standards proposed for drinking water criteria (EPA).
(continued)
-------
TABLE 2 (continued)
Sludge
and EPA
Allowable
Values
Sludge A
Sludge B
EPA
Material
Sludge
Solids
Sludge
Liquids
Sludge
Solids
Sludge
Liquids
Values
obtained
from
Ref. 9 and
Lab Sulfate
Symbol S%
mg/kg — *
mgA 1281.0
mg/kg 68750
mgA 2100
mg/£ 250t
10
Boron Chloride
B Cl
385 1330.0
lU.O 675.0
185 300
71.2 670
0.75* 250t
Nitrogen Nitrogen
Vanadium Nitrite Nitrate
V N02, N N03, N
162
-------
SECTION 6
SELECTION AND PROPERTIES
OF SOIL MATERIALS AND LINERS
The soil and the liner materials selected for use, including their physi-
cal properties, are described in this section. Emphasis was placed on the use
of admix and spray-on type materials for liners. The selection of candidate
liners was based on prior experience with the materials; however, a screening
process that included a permeability test as a basic requirement resulted in
deletion of many of the materials due to a very highly permeable condition.
Similar screening processes were used to select a soil type for the admix and
spray-on materials. For the soil selection, permeability was a major require-
ment, but the soil had to have the capability of being admixed on an economi-
cal basis with a particular selected candidate material.
SELECTED SOIL MATERIALS
The selection of -soil types for use in the study was primarily based on
experience gained during soil stabilization, dust pallation, and waterproof-
ing. A soil of high permeability (>10~^ cm/sec) was considered to be the
most applicable for evaluating the membrane and spray-on liners in that it
would permit any leakage of the liners to be readily detectable. However,
from an economical standpoint, the high permeability soils are not suitable
for the admix materials because of the high percent of admix that would be
required. Therefore, a less permeable (finer-grained) soil was used with the
admix materials. Based on this rationale, a silty sand was selected for eval-
uation of the membrane and spray-on liners and a clayey silt was selected for
evaluation of the admix liners. The two soil types are considered represen-
tative of typical soils that might be encountered in a disposal area.
Silty Sand
A brown, nonplastic, silty sand (SM) with a specific gravity (Gs) of
2.68 (Unified Soil Classification System (USCS)) was selected. The gradation
curve is shown in Figure 7- The standard compaction test procedure indicated
the optimum water content to be 12.7 percent and the maximum dry density to
be 111 Ib/cu ft (Figure 8).
Clayey Silt
A light brown, slightly plastic, clayey silt (ML) with a GS of 2.71
(USCS) was selected. The gradation curve is shown in Figure 7 also. The
standard compaction test procedure (ll) indicated the optimum water content
to be 17.3 percent and maximum dry density to be 106 Ib/cu ft (Figure 8).
18
-------
100
3 IN.
IOOO
1OO
- IN.
U. S. STANDARD SIEVE SIZE
NO. 4 NO. 1O
NO. 4O_
.NO. ZOO
i.a
GRAIN SIZE IN MILLIMETERS
O.t
O.OI
O.OOI
COB8US
GRAVEL
Come I
SAMP
Cotot
Medium
Rue
SILT 00 CLAY
Sample No.
Elev or Depth
Classification
Nat WC
LL
PL
PI
Project
Area
Boring No.
GRADATION CURVES
Date
f!,;1" ton (Tr«i.iuc«nw(eM ino-i-itoi)
Figure T. Gradation curves for soil materials.
-------
H
LL
•x,
CD
_l
K.
Q
112
—
o
0
/
.
/
/
S
^
*— - ™
^*«
OPTIMUM V
*^
CL
*°S
.A'
^
V
VE
k
s.
Y J
i
\
5IL
V
\
T
VATER CONTEN1
v
\
>
r =
MAXIMUM DRY DENSITY =106
I
V
\
17.3%
LB./FT3
12
14 i6 ie
WATER CONTENT, PERCENT
20
22
Figure 8. Moisture-density curves for test soils.
20
-------
SOIL PERMEABILITIES
The permeability of the two soil types was determined using standard
laboratory techniques (SLT) (ll). These values are presented in Table 3.
The permeability determined using SLT would identify these two soil types
further. Of more immediate importance, these values would be compared with
that value determined using a typical test cell apparatus described in
Section U under conditions as outlined below. It should be pointed out that
some very important differences exist between the two test methods: the SLT
procedure called for deaired, distilled water, the test cell apparatus (TCA)
did not; the SLT procedure called for an oven-dried sample that is saturated
before the test begins, the TCA did not; the SLT procedure called for the
entire specimen to be vibrated to the correct thickness/density in one layer,
the TCA did not; and the SLT procedure called for the head to be regulated to
avoid high/large hydraulic gradients, the TCA did not. These differences
indicate the inherent strength and/or weakness of this particular test situa-
tion. It was the intent of this investigation to use the TCA instead of SLT
to duplicate insofar as possible the expected field test conditions.
TABLE 3. SLT AND TGA PERMEABILITY VALUES
Permeability
Conditions cm/sec X 10
SLT Values
Silty sand - constant head method
Clayey silt - falling head method 0.57
TCA* Values
Water (only) 28,500
6-in. compacted silty sand, water 8l
6-in. compacted clayey silt, water l6
6-in. compacted silty sand,
5-gal Sludge A plus water ^9
5-gal Sludge B plus water ^7
6-in. compacted clayey silt
5-gal Sludge A plus water 7
5-gal Sludge A plus water 1
* Test cells filled as noted, with porous plate and drain tube in place.
The permeability of a typical TCA was determined to ensure that this
value was at least as great as the permeability of either test soil selected.
To do this, a test cell with porous plate, drain port, and drain tube in
21
-------
place was filled with tap water to a level U in. below the top of the test
cell and allowed to drain freely into a collection device. The permeability
was calculated by measuring the amount collected and the time during which
it was collected. (See Section 8 for other test results data.) The permea-
bility value obtained in this way (Table 3) indicated that the TCA would not
interfere with subsequent similar measurements described below.
Each test soil was compacted 6 in. deep at optimum density in separate
test cells (see Section 7 for compaction techniques). Each test cell was
carefully filled with tap water, and the permeability was calculated and
listed (Table 3). The permeability of the silty sand is almost six times
less in the test cell than that determined by the SLT, whereas the clayey
silt is 16 times greater than its corresponding SLT value. The permeability
value of silty sand is less when obtained in the test cell primarily because
the water level was not held constant; however, the clayey silt value is
greater because the soil was not saturated prior to testing. The test
started when the water level reached k in. from the top of the test cell.
A comparison of the selected soil permeability values determined by SLT
and TCA was discussed previously. These TCA values also provided an inter-
mediate point (permeability value) for the same setup as before with sludge
added. The next test series would determine whether the sludge/sludge liquor
increases or decreases the permeability of the TCA.
Six inches of compacted silty sand was placed in each of two test cells
and 6 in. of compacted clayey silt was placed in each of two test cells.
Approximately U gal of Sludge A was added to the test cells, one with com-
pacted silty sand and one with compacted clayey silt. Approximately k gal
of Sludge B was added to the remaining two test cells. The tap water was
added until the liquid reached a level h in. below the top of each test cell
and was allowed to drain freely as before. Adding sludge to a particular
test cell/compacted soil combination reduced the permeability value of that
system by about one half. Actual values are listed in Table 3.
The permeability values listed in Table 3 show how each succeeding step
of adding compacted soil and sludge reduced the permeability of the test cell
apparatus. The table was important in that it would indicate whether or not
the final variable, the liner itself, was reducing the TCA permeability.
Table 3 thus became the data base for all liners. Any liner in a test cell/
soil/sludge exhibiting permeability the same as or greater than that of a
similar although linerless configuration in Table 3 would be closely ex-
amined and probably rejected.
LINER SELECTION AND TESTING
In the past, admix materials were added to roadway/runway soil primarily
to increase the base or subbase bearing capacity (soil strength). More
recently, admix materials have found increasing use as modifiers to improve
the workability of a soil or to substantially reduce its susceptibility to
water. Similarly, spray-on materials are applied to control dust or prevent
weathering cycles including rainfall from eroding the soil surface, but the
more expensive, more time-consuming permeability tests normally have not been
22
-------
conducted. It became apparent that a reasonably fast method of determining
permeability for various admix and spray-on materials at various application
rates would be necessary to achieve the objectives of this study.
The procedure used for the admix liners consisted of preparing the test
specimens and compacting the material in a Harvard miniature test apparatus
(ll). For the spray-on liners, soil specimens vere prepared and compacted
in the Harvard miniature mold, and the spray-on materials were applied to the
top surface of the soil specimen. Both admixed and spray-on specimens were
allowed to cure for 7 days under humid conditions. Following the curing
period, a rubber membrane was placed around the top of the mold to form a
watertight connection to a tube. Water was introduced into the tube to
provide a 2-ft constant head on the liner materials. The water permeating
through the specimen was collected and measured over a known period of time
and from this the permeability was determined.
A deviation from this procedure was required for screening the asphaltic
concrete mix because of the size of aggregate in the mix. All admix speci-
mens were prepared 2 in. thick by 11-5/8 in. in diam and placed in a test
cell. The test cell was filled with water, and the permeability of a par-
ticular mix design was determined in the same manner as for the selected
conditions described above and listed in Table 3.
The prefabricated membrane materials were tested for leakage (pinholes)
or other abnormalities by the use of a 21-in. standpipe with a bell shape on
the lower end as shown in Figure 9- The membrane was placed on the bell end,
sealed with silicone, and secured with a ring and'"C" clamps. The standpipe
was filled with water that was allowed to remain for an extended period of
time, usually 15 to 20 days. Leakage was detected by the accumulation of
moisture in a container beneath the device.
Results of the screening process and selection of liner materials are
discussed in the following paragraphs.
SELECTED LINER MATERIALS
The items selected for exposure testing as liners in cells containing
sludge are listed in Table k.
Admix Liners
The quantity of admix to be added to the soil for preparation of the
liners was based primarily upon experience with the use of admixtures to
improve the strength, durability, or workability of soils in various civil
engineering projects. In some cases, the admix quantity used was recommended
by the admix procedures. Although several tests, including permeability,
density, compressive strength, penetration of asphalt, and viscosity of
asphalt, were performed on the admix liners, permeability was the prime
measurement used to select the percentage of an admix.
23
-------
WATER IN
OUT
JOIN WITH
4 "C" CLAMPS
MEMBRANE
Figure 9. Pinhole test device for membrane liners,
-------
TABLE U. SELECTED LINER MATERIALS
Material Name Percent/Description/Type
Admix Liner Material
Lime Hydrated ASTM C lUl-67*
Portland cement Type I ASTM C 150-78t
Cement with lime It percent Type I Portland cement
6 percent hydrated lime
M1T9 U percent polymer, bentonite blend
Guartec UF h percent light gray powder
Asphaltic concrete 11 percent asphalt cement
1/2 in. (max.) aggregate
TACSS 020 6 percent blackish-brown liquid
TACSS 025 6 percent blackish-brown liquid
C^OO 15 percent fine-ground powder
GST 15 percent fine-ground powder
Spray-on Liner Material
DCA-1295 3A gal per sq yd polyvinyl acetate
Dynatech 3A gal per sq yd natural rubber
Uniroyal 3A gal per sq yd natural latex
Aerospray 70 3A gal per sq yd polyvinyl acetate
ACUO 3A gal per sq yd asphalt cement
Sucoat As-supplied molten sulphur
Prefabricated Membrane Liner
Total liner As-supplied elasticized polyolefin
Tl6 As-supplied black chloroprene-coated
nylon
NOTE: For manufacturer/address, see Appendix A.
* ASTM. 1978. Standard Specifications for Hydraulic Hydrated Lime for
Structural Purposes. In: 1978 Annual Book of ASTM Standards, Part 13,
Designation: C 1^1-67 (rev 78)'. Philadelphia, Pennsylvania.
t ASTM. 1978. Standard Specifications for Portland Cement. In: 1978
Annual Book of ASTM Standards, Part lU, Designation: C 150-78.
Philadelphia, Pennsylvania.
25
-------
Admix materials produced "by Takenaka Komuten Company (Japan) are iden-
tified as TACSS 020, TACSS 025, CUOO, and CST. They were included in the
study based upon data presented by the company that the admixtures had a
high potential for creating an impermeable condition. The Takenaka Company
provided the materials and personnel to assist in formulating the mixes used
as liner specimens.
Asphaltic Concrete—
The asphaltic concrete mix used consisted of 1/2-in. maximum-size
aggregate with an 11 percent asphalt content. The material was compacted in
2-in.-thick by ll-5/8-in.-diam specimens for installation in the test cells.
The 11 percent asphalt content is not unusual in preparing mixes for pond and
canal liners where impermeable mixtures are desired.
Portland Cement—
Type I Portland cement, which is readily available in most areas, was
selected as an admix to produce higher strength in otherwise acceptable
soils. Trial applications of 6, 8, and 10 percent cement admix were prepared
and subjected to permeability tests. The specimens with 6 and 10 percent
admix did not leak whereas the specimen at 8 percent had slight leakage. No
reason for the slight leakage could be found; however, the larger application
rate of 10 percent of the dry weight was selected.
Portland Cement with Lime—
Lime or calcium hydroxide, commonly called hydrated lime, is readily
available and can be added to soil to reduce the volume change potential and
render the soil easier to compact. Although both cement and lime have been
used separately in large quantities to stabilize soil, very little has been
done with these two materials in combinations. It was believed that some
combination of the two materials would produce the desired benefits of both
materials: an increase in strength and a decrease in volume change poten-
tial. It is known that some percentage of lime (approximately 1 percent) is
lost due to carbonation, which is the reaction of calcium with carbon dioxide
in the air, so an arbitrary combination of k percent Type I Portland cement
and 6 percent hydrated lime was selected and tested. When the test specimen
failed to leak, this application rate (both percents of the dry soil rate)
was accepted, and the combination of the two materials was used as one of
the admix materials.
ChOO—
The C^OO material is a fine-ground powder produced in Japan. It is
reported to be very similar to cement with additional (unspecified) addi-
tives. A large variety of uses is well documented by the Japanese. This
material was applied at 15 percent of dry soil weight following tests of
5, 10, and 15 percent.
GST-
There were no essential differences noted between the CST material and
C^OO described above. It was applied at the same rate as the
26
-------
Guartec UF—
Guartec UF is a highly refined, unmodified gum produced by grinding the
guar bean into a fine powder. The guar bean is a legume plant that is native
to India but is now grown in northern Texas and southern Oklahoma. Typical
properties are a free-flowing powder, 12 percent maximum moisture with
99 percent passing the 100 mesh screen. The bulk density (packed) is 55 lb/
cu ft. It is described as having five to eight times the thickening power of
starch. It was reasoned that this material would swell to fill the soil
voids. The application rate of k percent of the dry soil weight resulted
in a specimen which did not leak and was used in the test cells.
Lime—
Lime was tested and applied at the rate of 10 percent of the dry soil
weight for comparison with Portland cement.
KL79--
M1T9 is a preblended mixture of water-swellable polymers and bentonite.
This material has been widely used as a sealant for reservoirs and is re-
ported effective in all soil types ranging from sand to clayey soils. The
material was applied at the rate of U5 tons per acre, approximately h percent
of the dry soil weight, as suggested by the supplier.
TACSS 020—
TACSS 020 is a blackish-brown transparent liquid (Gs = 1.115) produced
in Japan. A proprietary liquid catalyzer may be used to adjust the cure
time. This material was applied at the rate of 6 percent of the dry soil
weight as suggested by the supplier.
TACSS 025—
TACSS 025 is a blackish-brown liquid (Gs = 1.120) produced in Japan. A
proprietary liquid catalyzer may be used to adjust the cure time. This
material was also applied at the rate of 6 percent of the dry soil weight as
suggested by the supplier.
Pertinent physical data for the admix materials prior to being sub-
jected to the sludge (zero time data) are presented in Table 5.
Spray-on Liners
The materials used for spray-on liners were selected primarily from
items previously evaluated for dust control for military applications (13).
The selection was based on experience in regards to ease of application,
danger to personnel in applying or using, and subsequent behavior when ex-
posed to climatic conditions. One material, a molten sulfur product that
EPA suggested as a candidate material, was supplied by the Chevron Company
in a premolded specimen made the size for installation in the test cells.
Other than the molten sulfur product, the materials were applied at a
uniform rate of 3A gal/sq yd based on experience gained in use for dust
control. This rate was considered adequate to provide complete coverage,
preclude thin areas where pinholes or air bubbles might develop, and would
not be of sufficient quantity so that flow would occur. Experience indicates
that greater application tends to flow.
27
-------
TABLE 5. PHYSICAL TESTS - ADMIX LINERS
Zero Time (Control Data)
Liner Material
Clayey silt
Quart ec UF
Portland, cement
M179
Lime
TACSS 020
Cement plus lime
TACSS 025
CltOO
GST
Liner Material
Asphalt concrete
Application*
Rate, %
n/a
h
10
U
10
6
^ 6
6
15
15
Application*
Rate, %
115? asphalt
1/2-in.
aggregate
Water Dry
Content Density
% Ib/cu ft
16.6
17A
16.6
13.2
17.3
16.2
16.1
16. It
15-9
llt.lt
103.5
90.0
102.8
103.9
101.0
106.3
IQlt.l
10lt.6
105.lt
105.2
Asphalt
Content
%
10.lt
Height Axial
'Diameter Strain
H/D AH/H, JS
2.051
2.0^2
2.155
2.009
2.153
2.151*
2.172
2.173
2.111
1.792
3.1
5.9
1.0
n/a
1.0
6.3
1.0
5.0
1.0
1.0
Penetration
0.1 mm
60
Unconfined
Compression
Ib/sq. in.
38.U
13.9
663
<5
2k2
179
503
161;
721
1160
Viscosity
Passes
2959
NOTE: UC tests followed seven days humid cure.
* The application rate is based on the percent of dry soil weight or dry
aggregate weight.
The spray-on liners were subjected to permeability, density, and tensile
strength/elongation tests.
ACltO—
ACltO is an asphalt material refined to meet specifications for paving,
industrial,and special purposes. Specifications for this material require a
viscosity of 1+000 +_ 800 poises at a temperature of 135°C (275°F) and a pene-
tration of 20 (minimum) at 25°C (77°P) for 100 grams for 5 sec. This material
requires a high temperature to flow (300 to UOO°F), and it was applied at the
rate of 3A gal/sq yd.
Aerospray 70—
Aerospray 70 is a polyvinyl acetate material weighing about 9.2 Ib/gal.
This liquid is white and cures to form a clear flexible film. The application
rate was 3A gal/sq yd. This material has been used to control erosion in
areas of new vegetation.
28
-------
DCA-1295--
DCA-1295 is similar to Aerospray TO with additional plasticizers and
other additives to increase shelf life and help produce a more flexible film.
The application rate was 3A gal/sq yd. This material was developed to con-
trol dust during military operations.
Dynatech—
Dynatech is a natural rubber latex compound designated l-H-10 formula-
tion No. 267. It was applied at a rate of 3 A gal/sq yd. An experimental
product, it is one of the materials considered for the military dust control
program.
Sucoat—
Sucoat is a molten sulfur product which is placed at high temperature
(300 to UOO°F) and forms a strong solid upon curing. Four 3/8-in.-thick
discs, approximately 11-5/8 in. diam, were supplied by the manufacturer for
testing, and they were installed in the cells as received. This is a new
product described as a quick setting, watertight, coating compound.
Uniroyal—
Uniroyal is a black natural latex designated L92U1 by the manufacturer.
It was applied at the rate of 3A gal/sq yd. This experimental product was
one of the materials that passed the traffic phase of the dust control
program.
Pertinent physical data for the spray-on liner material for zero time
are presented in Table 6. Figure 10 shows a typical spray-on material (AC kO)
being cured in the laboratory. All spray-on materials were cured for 0-time
physical testing in a similar fashion.
Prefabricated Membrane Liners
The following prefabricated liners were selected for evaluation and were
subjected to permeability, density, and tensile strength/elongation tests.
Total liner—
Total liner is an elasticized polyolefin approximately 20 mils thick.
The membrane was applied as received. This material was furnished by the
manufacturer at the request of the EPA.
T16--
Tl6 is a chloroprene-coated nylon approximately 18 mils thick. This
composite material is formed from a single-ply nylon fabric coated with neo-
prene and weighs 18.5 oz/sq yd. This membrane was developed at WES as an
expedient airfield pavement surfacing material. The membrane was applied as
received from the producer.
Pertinent physical data for the prefabricated membrane liner material
for zero time are presented in Table 6.
29
-------
TABLE 6. PHYSICAL TESTS - SPRAY-ON AND MEMBRANE LINERS
Zero Time (Control Data)
Thickness
Liner Material in.
Total liner
Tl6
DCA-1295
Dynatech
Uniroyal
Aerospray 70
Sucoat*
Liner Material
ACAO
0.023
0.018
0.219
0.093
0.111
0.158
Weight Density
grams Ib/cu ft
7.77 5^8
8.95 75.75
112. U 8l.ii2
29.98 55-50
35.39 53>5
80.77 82.27
Asphalt
Content
n/a
Application Apparent
Rate Elongation
Ib/sq. yd %
0.92
I. Ok
13. U2
3.87
h.h3
9.71*
NOT
Penetration
0. 1 mm
^9
136
26
172
U86
615
235
AVAILABLE
Breaking
Strength
Ib
5M»
^82
127
128
122
106
Viscosity
Passes
8237
* Four discs 3/8 in. thick received from manufacturer. All four used in test
cells.
Figure 10. AC^O curing in a plastic mold.
30
-------
SECTION 7
PREPARATION AND INSTALLATION OF LINER AND
SLUDGE MATERIALS ON TEST CELLS
GENERAL PROCEDURES
The sequence for fabrication of the test cells was basically the same for
all cells and followed the routine presented in Section k. The method of pre-
paring and installing the liners is discussed in this Section. Since compac-
tion of the soil materials (and liners in the case of the admixed materials)
was a pertinent part of the preparation of all of the liner/cell combinations,
the details of the procedure are presented initially to obviate further dis-
cussion per individual liner types.
COMPACTION DEVICES AND METHODS
Compaction devices consisting of two different size footings were pre-
pared for the Instron machine (Figure 11). These devices were used to stati-
cally compact soil in the test cells in 2-in.-thick layers. The surface of
the compacted layer was scarified and another layer added. In this manner,
three layers of a predetermined weight of soil were compacted using a proce-
dure that closely parallels the one used in preparing Harvard miniature speci-
mens (Figure 12). Finally, an 11.5-in.-diam compaction foot was attached to
the Instron machine, and the soil surface was leveled throughout to a 6-in.
depth, assuring the desired optimum density. The footings were mounted on
shafts of sufficient length to reach the lowest part of the cell.
LINER PREPARATION
Admix Liners^
The admix-type liners were prepared in accordance with the proportions
discussed in Section 6. Each admix material was thoroughly mixed with the
clayey silt, placed in a test cell, and compacted; then liners were allowed
to cure for seven days at T8°F and 50 percent humidity. The only deviation
was the asphaltic concrete, which was prepared separately in a special mold
having the same diameter as the test cell. This was necessary in order to
obtain sufficient density of the mix during compaction and also prevent any
damage to the underlying silty sand soil on which it was placed. This re-
sulted in a 2-in. thickness of asphaltic concrete over a 6-in. layer of com-
pacted silty sand. This was the only admix material used in conjunction with
the silty sand soil. All others were mixed with the clayey silt soil and
compacted in a test cell.
31
-------
•
Figure 11.
with both
The Instron machine
compaction footings.
Figure 12. Typical operation using Instron
machine and U.5-in.-diam footing to compact
soil layer in a test cell.
-------
Spray-on Liners
The spray-on liner materials were applied to the surface of the silty
sand soil. The silty sand was compacted 6 in. deep in the test cell at opti-
mum moisture and density and was allowed to cure (normally two to three days)
at 78°F and 50 percent humidity. The spray-on materials were placed on the
surface (3A gal/sq yd) and allowed to cure in accordance with the manufac-
turer's recommended time. The cure time was usually about four hours or less.
Prefabricated Membrane Liners
The prefabricated membrane liners were prepared to include a seam or
joint in the mid-portion of the specimen, which was then cut to the diameter
of the test cell. The seam was considered to be a necessary part of the test
as one would certainly be encountered in covering a large area. The liners
were placed on 6 in. of compacted silty sand in the test cell.
SEALANT
A silicone sealant was used to seal around the periphery of the liner and
test cell wall. The sealant was used with a primer for best results. The
primer was placed only on the PVC test cell walls in bands approximately
3 in. wide in the area where the sealant would be placed to help assure a good
bond between the primed test cell wall, forming a triangular-shaped wedge that
extended approximately 1 in. out on the liner and 1 in. up the test cell wall.
The sealant was allowed to cure until it was dry to the touch.
FGD SLUDGE
The FGD sludges were collected and transported in metal cans lined with
heavy vinyl bags. Prior to placement in the cells, the sludge was thoroughly
mixed using a portable mixer with extended mixing blades (Figure 13). After
they were mixed, the sludges were added to the test cells at a rate of approx-
imately U gal per test cell.
CHEMICAL ANALYSIS DATA BASE
A chemical analysis of the sludge solids and sludge liquids was con-
ducted on both Sludges A and B "as received." The analysis included measure-
ment of the concentration in mg/£ for 20 parameters (see Table l) and further
identification of the sludges used. (See Section 5 and Table 2.) It was
also deemed desirable to establish a chemical analysis data base for each
different testing situation. Therefore, a chemical analysis was conducted on
the leachate from unlined test cells loaded as follows:
Lab Symbol Sludge Type Soil Type
1-100 A Clayey silt
2-100 A Silty sand
1_1|00 B Silty sand
2-1*00 B Clayey silt
33
-------
Additionally, each test cell was filled vith tap water to a level h in. from
the top. By comparing this chemical analysis with the analysis taken after
the liquid passes through the liner, these initial data (Table T) will serve
to indicate whether a liner that passes liquid is helping solve a potential
problem or contributing to the problem.
Figure 13. Portable mixer with extended
mixing blades.
-------
TABLE 7. CHEMICAL ANALYSIS DATA
Leachate from Unlined Test Cells and EPA Allowable Values mg/£
Sludges
and EPA
Allowable ID Arsenic Beryllium Cadmium Chromium Cyanide Copper Mercury Magnesium Manganese Nickel
Values No. As Be Cd Cr Cn Cu Hg Mg Mn Ni
Sludge A
Sludge B
EPA
2-100
1-100
1-1*00
2-l|00
*
0.003
0.002
O.OOU
o.ooU
0.05
0.005
0.005
0.005
0.005
O.llt
0.002
0.002
0.003
0.003
0.01
0.001
0.001
0.001
0.001
0.05
0.029
0.01
0.034
0.01
0.005*
0.013
0.001
0.003
0.003
0.2*
0.0002
0.0002
0.0002
0.0002
0.002
65.1
22.2
7U.1
20.0
n/a
0.01
0.35
0.01
0.01
0.05
0.005
0.005
0.005
0.005
O.lt
vn * Values obtained from References 9 and 10.
t Freshwater aquatic life criteria.
=f= Freshwater and marine organisms criteria.
(continued)
-------
TABLE 7 (continued)
Sludges
and EPA
Allowable
Values
Sludge A
Sludge B
EPA
ID
Wo.
2-100
1-100
i-Uoo
2-lkOO
f
Lead Selenium Zinc Sulfite
Pb Se Zn SO^
0
0
0
0
0
.006 E*
. 010 E*
.005 E*
.005 E*
.05 0.01
0.020 1.0
0.020 1.0
0.016 i.o
0.026 1.0
5.04= n/a
Sulfate
soil
2U1.0
^2.0
297-0
36.0
250*
Boron Chloride
B CL
lU.7
1.1
7.1*
0.6
0.75§
83.0
95.0
78.0
79.0
250*
Vanadium
V
0.021
0.005
0.018
0.005
n/a
Nitrogen
Nitrite
N02, N
Ik.
0.
31.
0.
10.
3
01
6
001
0
Nitrogen
Nitrate
N03, N
75.6
0.33
Vf.5
0.05
10.0
* E = equipment being repaired.
U)
^ t Values obtained from References 9 and 10.
4= Secondary (EPA) standards proposed for drinking water criteria.
§ Irrigation criteria.
-------
COMPLETION OF ASSEMBLY
The top plates were attached, and the cells were placed in the holding
area. The pressurization system was installed and attached to the cells.
The system for collection of the leachate was assembled, and the exposure
test was commenced. Following the first month of 0 psig (atmospheric pres-
sure), the pressure system was activated and the pressure was increased to
2 psig, simulating placement of approximately 3 ft of sludge. Similarly, the
pressure was increased 2 psig each month for a total of 10 months (30 ft of
head). It was reasoned that a disposal area of a size less than 1-year
capacity probably would not be economically feasible, yet one half the test
cells would be removed after only 12 months duration, and it seemed desirable
to have some portion of that period at the full "design" condition, i.e.,
30 ft of head.
IDENTIFICATION SYSTEM
A method to identify the test cell sludge/liner combination was devel-
oped. Each liner material was assigned a number from 01 to 18; these two
numbers were followed by either a 1 (for 12 months exposure time) or a 2
(for 2k months exposure time); and finally this number was followed by a
letter (A for Sludge A, or B for Sludge B). Thus, each test cell was
assigned an identification number and all particulars were noted on a master
sheet. For example, 121B on a test cell indicates that the liner is lime,
the test duration is 12 months, and the sludge is "B", a FGD sludge from an
eastern coal limestone-scrubbed process.
37
-------
SECTION 8
TEST DATA
At the end of the first 12-month period, 36 test cells were depres-
surized at the rate of 2 psig per hour and removed from the holding areas for
disassembly. All remaining liquid and sludge solids were removed from the
liner in a way that would not damage the liner or test cell.
ADMIX LINER MATERIALS
Admix liner materials were removed for testing by coring with a 3-in.-OD
diamond-studded, hollow-core bit. It was necessary to core each admix liner
three times to help ensure duplicate test specimen values for each situation
(test cell) because it was not possible to determine if a cored sample
sheared during coring. This was not immediately detectable for two reasons:
there was no discernible difference in the coring machine operation when
shearing occurred and because the test cell had to be transported to an area
where the base plate could be removed and the cored samples extracted. Since
the bit was not allowed to penetrate the 6-in. soil layer more than 5-3A in.
(to prevent damage to the base plate), the base plate had to be removed and
1/U in. of the soil scraped away before the cored specimen could be removed
and examined (Figure lU). Each specimen was trimmed as necessary for the
Figure lU. Soil being removed from bottom of test
cell lined with TACSS 025.
'
-------
unconfined compression test and the specimen was measured, weighed, and
tested. Water contents were determined after testing in unconfined compres-
sion (Figure 15). These values and any pertinent observations are listed in
Table 8. The zero time data for each liner are presented in Table 8 for ease
of comparison with the 12-month data.
Nine of the admix liner materials were handled in this fashion. The
tenth admix liner material, asphaltic concrete, was cored and the asphalt
material was extracted (from the aggregate added initially and whatever
infiltrated the liner). The percent asphalt was determined and the asphalt
was examined for penetration and viscosity values. These data are listed in
Table 8 with the corresponding zero times values. The permeability values
of the admix liners will be discussed along with the spray-on and membrane
liners since the permeability remarks apply to all three liner types.
SPRAY-ON AND PREFABRICATED MEMBRANE LINERS
Following depressurization and the liquid/sludge removal above the
spray-on and prefabricated membrane liner material, the silicone edge sealer
was peeled from the test cell wall, and in the case of the prefabricated
membrane, the liner was rolled back from the walls and removed. This was
somewhat more difficult with the spray-on liners because the liquid pene-
trated the soil surface and formed a film that bonds to the soil. However,
with care, it was possible to remove the spray-on liner from the soil sur-
face. Gently washing the spray-on liner with aerated tap water removed the
remaining loose soil particles and the sludge solids. Some soil particles
were completely encapsulated and became part of the liner, and probably other
soil particles/sludge solids not so completely bound resisted the cleaning
efforts described above, but no further attempts were made to dislodge them
for fear of inadvertently damaging the liner itself. The washed samples were
cut into 1;- by 6-in. grab test samples, measured (thickness) and weighed, and
kept under tap water until four hours or less before the time of the actual
grab test. These results are presented in Table 9-
Five of the spray-on and two of the prefabricated membrane liners were
handled in this fashion. The AC^O spray-on material formed a highly flexi-
ble film that could not be tested by the grab test method. Since the AC^O
is an asphalt material, samples of it were taken and the asphalt content,
penetration, and viscosity values determined (Table 9).
PERMEABILITY
Each test cell had its own collection system (see Figure 3), and any
leachate from a test cell would exit through the drain port and proceed via
plastic tubing to a plastic container. Each container was checked regularly,
and the contents were noted for several reasons. First, even though a liner
material might prove permeable, the permeability might be so low that the
environment would remain essentially unaffected. Secondly, a permeable liner
material could be a very effective filter and the chemical analysis of the
leachate could show it to be of no consequence to the environment.
39
-------
a. Portland cement
b. TACSS 020
Figure 15. Admix liner materials following 12 months
of inundation and unconfined compression test.
:
-------
TABLE 8. PHYSICAL .TESTS - ADMIX LINERS
Application Water
ID
Ho.
000*
080
08lA
081B
100
101A
101B
110
111A
111B
120
121A
121B
lltO
lltlA
ll«lB
150
151A
151B
160
161A
161B
170
171A
171B
180
181A
l8lB
090
09 1A
091B
Liner Rate
Material %
Clayey silt n/a
Quart eo UP k
Portland 10
Cement
ML79 It
Lime 10
TACSS 020 6
Cement plus It
lime 6
TACSS 025 6
CltOO 15
CST 15
Content
£
16.
17.
16.
21.
20.
13.
17.
20.
22.
16.
16.
16.
16.
20.
20.
16.
17.
18.
15.
20.
19.
lit.
19.
6
U
6
0
3
2
3
1
3
2
7
5
1
It
1
It
1
3
9
3
8
It
0
19.9
Asphaltic concrete
11$ asphalt
1/2-in. aggregate
Asphalt
10
11
10
Dry
Density
Ib/cu ft
103.5
90.9
TOO
102.8
103.0
103.6
103.9
101.0
100.8
101.7
106.3
105.9
105.9
IQlt.l
103.7
10U.lt
10lt.6
iolt.8
lOlt.O
105. U
10lt.2
105.6
105.2
106.2
105.3
Content
~M
.2%
.3%
Sample Height
Diameter
H/D
2.051
2.0U2
SOFT TO TEST
2.155
2.09U
2.111
2.009
2.153
2.073
2.073
2.15U
2.153
2.159
2.172
2.118
2.063
2.173
2.157
2.160
2.111
2.106.
2.171
1.792
2.118
1.953
Penetration
60
68
82
Axial
Strain
4H/H, %
3.1
5.9
1.0
1.0
1.0
n/a
1.0
1.0
1.0
6.3
6.6
6.3
1.0
1.0
1.0
5.0
7.0
7.0
1.0
1.0
1.0
1.0
1.0
1.0
, 0.1 mm
Unconfined
Compression
Ib/sq. in.
38.lt
13.9
663
1779
1893
<5
2U2
129l»
1200
179
1U8
162
503
1297
1U96
l6>t
Ilt7
lit It
721
1510
IPOll
1160
1792
2091
Permeability^
cm/sec x 10
0.117
0.006
0.001
Untreated soil -
humid cure.
Eight test cells
Remarks
tested following
7 days
attempted - all leaked.
Horrible odor developed, probably
tive of material breakdwon. Liner
poured from test
to test.
Very hard to core
cell - rejected.
samples .
indica-
material
Too soft
Same as Guartec above.
0.156
0.08!|
0.008
0.010
0. Oil It
0.052
Very hard to core
Very hard to core
samples .
samples .
2-psi back pressure failed to produce any
0.009
0.007
0.071
0.038
none
0.003
0.011
O.OOU
Viscosity, poises
2959
37lt9
29^5
bubbles that would indicate leaks .
Very hard to core
Very hard to core
samples .
samples.
Permeability, cm/sec x 10~°
0.298
2.805
* 0 - Control data, zero time.
-------
TABLE 9- PHYSICAL TESTS - SPRAY-ON AM) MEMBRANE LINERS
K>
Application
ID Liner
No. Material
010* Total liner
011A
011B
020 Tl6
021A
021B
030 DCA-1295
031 A
031B
OkO Dynateeh
Ol*lA
Ol*lB
050 Uniroyal
051A
051B
OfiO Aerospray 70
061A
06lB
130 Sucoat
131A
131B
Thickness
in.
0.023
0.022
0.025
0.018
0.018
0.017
0.219
0.177
0.103
0.093
0.100
0.113
0.111
0.088
0.086
0.158
0.071
0.096
0.1*20
Weight
rans
7. 77
9.10
9.80
8.95
15.38
16.62
112. It U
65. 1U
31*. 08
29.98
1+0.79
1*1.99
35.39
3l».31
32.93
80.77
38.61
96.00
320.83
Density
Ib/cu ft
51*. 58
63.66
62.98
75.75
88.77
9U.35
81. 1(2
88.95
55.1(0
55.50
61*. 23
58.72
53.U5
60.83
60.26
82.27
83.11
165.88
NOT
120.32
Rate
l"b/sq yd
0.92
1.07
1.15
l.OU
1.77
1.95
13.1*2
7.76
It. 06
3.87
1*. 79
U.95
It. 1(3
l*.0l*
3.89
9.7U
l».36
11.3U
AVAILABLE
37.88
LIHER SHATTERED WHEN TEST
Asphalt Content
070 ACl*0
071A
071B
NA
19.5
27.6
Apparent
Elongation
4,
136
573
1*6U
26
25
28
172
95
52
1(86
!*96
521
615
581*
607
235
17U
55
6
CELL RUPTURED
Breaking
Strength Permeability^
rb cm
5Ult
158
131*
1*82
31*5
37U
127
1*7
22
128
82
118
122
68
70
106
37
31*
225
UNDER PRESSURE
/sec x 10""
0.120
0.265
0.226
0.063
0.368
0.066
0.0l(l*
none
0.3l(l*
0.03H
o.oUo
0.085
0.061*
Penetration. 0.1 mm Viscosity, poises
59 8237
1(2
1(2
11*752
136UU
0.067
0.105
Remarks
Leakage apparently developed between liner and
sealant along 1/2- in. strip.
Leakage developed in two places between liner
and sealant. Total length of leaking strip
approximately 1/2 in.
The liner was discolored and apparently dis-
solving from chemical attack; two small holes
at liner edge, liner very thin elsewhere.
Liner and sealer separated and leak developed
although sealer/cylinder bond was good.
Liner and sealer separated approximately 3A
of the circumference of the liner.
Liner badly discolored and very thin in spots
apparently due to chemical attack.
Four discs 3/8 in. thick received from manu-
facturer. All four used in test cells.
Leaked near the center of the liner. No
apparent leaks around sealant. Liner ruined
when removed.
0 - control data, zero time.
-------
The coefficient of permeability of each liner material, k , was ap-
proximated using the formula Q = kiAt where Q is the quantity of leachate
collected; A, the area of the liner material exposed (for simplicity, the
gross sectional area of the test cell was used, diameter = 11-13/16 in.);
t , the time period in which leakage was collected; and i , the average
hydraulic gradient during the time period t. The permeability values are
tabulated in Tables 8 and 9.
FILTERABILITY
In order to assess the gross effects of liner behavior and liner compo-
sition on the liquid first released from a lined or unlined sludge pond, the
first 32 oz of liquid issuing from each test cell was collected and analyzed
chemically. Since duplicate test cells had been constructed for each liner,
duplicate samples were available for each membrane type that passed liquid.
The samples were collected over varying lengths of time, but care was taken
to avoid contamination of samples from dust or evaporation by using narrow-
necked plastic bottles with close-fitting collection tubes. Each sample was
submitted for analysis as soon as 32 oz had been collected. The methods of
chemical analysis are listed in Table 1. The chemical analyses of samples
are given in Tables 10 and 11. Conductivity and pH values for the samples
are given in Table 12.
These initial liquid samples (permeate water) consisted of a mixture of
soil pore water, material from the membrane, and sludge liquor (the liquid that
is a result of and saturated with the FGD sludges). Factors that affected
the composition of the initial permeate water samples were the following:
a. Initial composition of the pore water in the soil.
b. Composition of any additional water added to the soil during the
application of the liner material to be tested.
c. Composition of the sludge liquor.
d. Composition of material leached from or generated by the decomposi-
tion of the liner material.
e. Degree of mixing of soil pore water and permeating sludge liquor in
the water sample.
The soil pore water had considerable effect upon the permeate composi-
tion. Approximately O.U cu ft of soil (^0 to 50 Ib) was used in each test
cell. Moisture contents for the soils as used were between 13 and IT percent
by weight. Each soil sample, therefore, initially contained 96 to 128 oz of
water. Two different soil samples were used. The composition of the pore
water in the soils is best shown in the initial sample taken from linerless
test cells (see Table T).
During the installation of some spray-on or admixed liners, additional
water was added to the soil. Part of this liquid was also expelled in the
1*3
-------
TABLE 10. SUMMARY OF CHEMICAL ANALYSIS DATA
Sludge A
Leachate from Unlined Test Cells,
Lined Test Cells, and EPA Allowable Values, mg/£
Material
Silty sand
Ho liner
Total liner
T16
DCA-1295
Dynatech
Uniroyal
Aero spray 70
ACltO
Asphalt ic Concrete
Sucoat
Clayey silt
Guartec UF
Cement
M179
Lime
TACSS 020
Cement /Lime
TACSS 025
CltOO
CST
Values obtained from
Ref. 9 and 10
ID
Ho.
2-100
QUA
012A
021A
022A
031A
032A
OltlA
OU2A
051A
052A
061A
062A
071A
072A
091A
092A
131A
132 A
1-100
081A
032A
101A
102A
111A
112A
121A
122A
llllA
llt2A
151A
152A
161A
162A
171A
172A
181A
182A
Arsenic
As
0.003
<0.002
0.007
<0.002
<0 . 002
O.002
<0.002
O.OOlt
<0.002
<0.002
<0.002
<0.002
?*
<0.002
?*
<0.002
?*
<0.002
<0.002
0.002
<0.002
<0.002
O.OOlt
0.003
<0.002
<0 . 002
<0.002
<0 . 002
0.002
<0.002
O.OQlt
0.002
0.002
O.Ollt
?*
?*
<0.002
0.003
0.05
Beryllium
Br
<0.005
<0.001
<0.001
<0.001
<0.001
<0.005
<0.001
<0.001
<0.001
<0.001
<0.005
<0.001
<0.001
<0.001
<0.005
<0.005
<0.005
<0.001
<0.001
<0.005
<0.005
0.010
0.003
0.010
<0.001
0.008
0.010
0.011
<0.001
0.013
0.011
0.012
<0.005
O.llt
Cadmium
Cd
0.002
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
O.OliO
«0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.002
0.0lt2
0.0l»5
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
O.OOlt
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.01
Chromium
Cr
<0.001
0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.056
0.038
0.966
0.769
<0.001
<0.001
0.015
0.029
<0.001
<0.001
0.012
0.0lt2
<0.001
<0.001
<0.001
<0.019
0.05
Cyanide
Cn
0.029
<0.005
<0.005
<0.005
<0.005
0.010
<0.005
0.055
<0.005
<0.005
<0.010
<0.005
<0.005
<0.005
CI
CI
<0.01
CI
0.0ll5
O.OS't
0.079
<0.005
<0.005
O.OltS
0.065
0.0lt5
<0.005
<0.005
0.035
<0.005
<0.005
0.151
0.150
0.005*
Copper
Cu
0.013
0.003
<0.002
<0.002
<0.002
<0.001
<0.002
<0.002
<0.002
<0.002
0.001
<0.002
0.002
<0.002
0.001
0.002
<0.001
0.500
0.550
0.003
0.015
<0.002
<0.002
0.013
0.015
<0.002
<0.002
0.030
O.Ollt
0.002
<0.002
0.093
0.188
0.2§
Mercury
Hg
<0.0002
< 0.0002
<0.0002
<0.0002
<0.0002
< 0.0002
<0.0002
<0.0002
< 0.0002
<0.0002
<0.0002
0.0008
O.OOOlt
< 0.0002
<0.0002
<0.0002
< 0.0002
< 0.0002
0.0002
<0.0002
< 0.0002
< 0.0002
<0.0002
<0.0002
0.0030
<0.0002
<0.0002
<0.0002
<0.0002
<0.0002
<0.0002
<0.0002
< 0.0002
0.002#
Magnesium
Mg
65.1
82.lt
108.5
111.3
103.lt
git.o
123.8
l6l.lt
lltlt.lt
83.3
106.0
111.2
95.7
167.0
100.0
88.lt
22.2
lit 31.0
1259.0
<0.10
<0.10
101.5
9l». 3
<0.10
<0.10
263.3
206.5
<0.01
•=0.10
271.0
280.3
<0.01
<0.10
H/A
Manganese
Mn
<0.01
<0.01
19.3
15.3
<0.01
0.13
<0.01
7.6
8.1
8.0
0.06
<0.01
<0.01
10.6
<0.01
<0.01
0.35
1955.0
1788.0
<0.01
<0.01
1.3
3.6
0.01
0.01
23.8
lit. 6
<0.01
•=0.01
28.9
ltlt.lt
0.01
0.01
0.05
Nickel
Hi
<0.005
<0.005
0.022
0.019
<0.005
<0.005
<0.005
0.035
0.021
0.019
<0.005
<0.005
<0.005
0.023
<0.005
0.013
<0.005
U.23
3.1*6
<0.005
<0.005
0.025
0.038
O.Oltli
0. Oil U
0.025
O.OU6
0.052
O.OU2
0.033
0.033
0.058
0.120
o.it
? = Insufficient leakage to date («32 oz).
Freshwater aquatic life criteria.
Freshwater and marine organisms criteria.
Secondary standards proposed for drinking water criteria (EPA).
Irrigation criteria.
(continued)
-------
TABLE 10 (continued)
Silty
Material
sand
No liner
Total liner
T16
DCA-1295
Dynatech
Uniroyal
Aerospray 70
ACUO
Asphaltic Concrete
Sucoat
Clayey silt
Guartec UF
Cement
ffl.79
Lime
TACSS 020
Cement /Lime
TACSS 025
CltOO
CST
ID
No.
2-100
011A
012A
021A
022A
031A
032A
OltlA
OU2A
051A
052A
06lA
062A
071A
072A
091A
092A
131A
132A
1-100
081A
082A
101A
102A
111A
112A
121A
122A
lUlA
1U2A
151A
152A
161A
162
171A
172A
181A
182A
Values obtained from
Ref.
9 and 10
Lead
Pb
0.006
0.01
<0.003
O.Ollt
<0.003
0.019
<0.003
<0.003
0.018
0.005
0.008
<0.003
0.008
<0.003
<0.003
<0.003
0.010
0.07U
0.095
<0.003
0.017
0.005
<0.003
<0.003
<0.003
<0.003
<0.003
0.098
<0.003
<0.003
<0.003
<0.003
<0.003
0.05
Selenium
Se
E*
<0.003
<0.003
<0.003
<0.003
E«
<0.003
<0.003
<0.003
0.009
E*
<0.003
<0.003
<0.003
E»
E*
E«
<0.003
<0.003
E*
E*
<0.003
<0.003
0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
0.01
Zinc
Zn
0.020
<0.001
0.002
<0.001
<0.001
0.003
0.007
0.001
0.001
<0.001
0.008
<0.001
0.017
O.OOlt
O.OOU
<0.001
0.020
3.U5
2.86
<0.001
0.001
0.005
O.OOlt
O.OOlt
O.OOlt
<0.001
<0.001
<0.001
0.002
<0.001
<0.001
<0.001
0.006
5.0t
Prop.
Sulfite Sulfate
S03 SOj^
<1.0 2ltl.O
<1.0 210.0
<1.0 1320.0
1.0 Ilt20.0
<1.0 Itlt2.0
<1.0 371.0
lt.O
lt.O
3.6 61tO.O
2. It 620.0
<1.0 6.0
-------
TABLE 11. SUMMARY OF CHEMICAL A1ALYSIS DATA
Sludge B
Sludge Solids, Sludge Liquid, Leachate from Lined
and Unlined Test Cells, and EPA Allowable Volumes, mg/£
Material
Silty sand
No liner
Total liner
Tl6
DCA-1295
Dynatech
Uniroyal
Aerospray 70
ACl»0
Asphaltic Concrete
Sucoat
Clayey silt
Guartec UF
Cement
M179
Lime
TACSS 020
Cement /Lime
TACSS 025
CltOO
CST
Values obtained from
Ref. 9 and 10
ID
No.
011B
oi2B
021B
022B
031B
032B
OltlB
Ol*2B
051B
052B
061B
062B
071B
072B
091B
092B
131B
132B
2-1*00
081B
082B
101B
102B
111B
112B
121B
122B
lUlB
1U2B
151B
152B
161B
162B
171B
172B
l8lB
182B
Arsenic
As
O.OOli
<0.002
<0.002
<0.002
?*
<0.002
0.006
0.006
<0.002
— — 1*
<0.002
<0.002
<0.002
<0.002
<0.002
o.ooi*
<0.002
0.002
?*
o.ooU
0.006
0.007
0.005
?*
<0.002
<0.002
O.OOl*
O.OOl*
0.028
0.009
0.002
0.002
0.006
0.011
0.050
?*
O.OOl*
0.002
0.05
MOTE: Chemical insufficient, could not tie
* ? = Insufficient
t — = Insufficient
leakage
sample
* Freshwater aquatic life
Beryllium
Be
<0.005
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.005
<0.005
<0.001
O.OQl*
<0 . 005
<0.005
<0.001
<0.001
<0.005
0.005
0.009
<0.005
<0.005
0.009
0.010
<0.001
"<0.005
0.013
0.011
<0.005
<0.005
<0.005
0.011*
determined.
Cadmium
Cd
0.003
<0.006
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.003
O.Oll*
0.017
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.01
Chromium
Cr
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
o.oi*U
o.oi»o
0.31*0
<0.001
<0.001
0.538
0.205
<0.001
<0.001
0.039
0.026
<0.001
<0.001
0.120
0.008
0.029
0.05
Cyanide
Cn
0.03U
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
0.016
<0.005
<0.005
<0.005
<0.01
<0.01
<0.005
<0.005
CI
<0.01
<0.005
<0.005
0.032
<0.005
<0.005
0.033
0.025
<0.005
CI
0.022
0.033
CI
0.023
0.103
0.09lt
0.082
0.005§
Copper
Cu
0.003
0.002
<0.002
<0.002
<0.002
<0.002
<0.002
<0.002
0.007
<0.002
<0.002
0.002
<0.001
0.001
<0.002
<0.002
0.003
0.003
O.U50
O.U67
0.025
0.005
0.003
0.020
0.013
<0.002
<0.002
0.017
0.010
<0.002
<0.002
1.23
0.259
0.200
0.2
Mercury
Hg
< 0.0002
< 0.0002
< 0.0002
<0.0002
< 0.0002
< 0.0002
< 0.0002
<0.0002
— t
< 0.0002
<0.0002
0.0008
< 0.0002
<0.002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
< 0.0002
<0.0002
O.OOOlt
<0.0002
< 0.0002
< 0.0002
< 0.0002
<0.0002
< 0.0002
0.002#
§ Freshwater and
to date («32 oz) .
to analyze
criteria.
for all parameters.
Magnesium
Mg
7>*. 1
136.5
11*0.6
158.5
87.1»
131.8
lltl.l
Ilt9.7
59.0
70.3
108.U
133.3
103.0
92.6
99.0
122.7
102.0
20.0
1197.0
1020.0
<0.10
113.3
109.1*
<0.10
<0.10
229.1
253.7
<0.10
<0.10
261.0
299.2
<0.10
<0.10
<0.10
n/a
Manganese
Mn
<0.01
0.1*
3.9
1.0
<0.01
13.3
<0.01
0.06
0.5U
9.9
O.Oll
<0.01
<0.01
<0.01
11.6
0.5
1.1* '
<0.01
1766.0
11*16.0
<0.01
0.06
1.1
<0.01
<0.01
28.3
31*. 1*
<0.01
<0.01
39.5
50.1
<0.01
<0.01
<0.01
0.05
Mickel
Ni
<0.005
0.015
0.008
0.007
<0.005
0.019
<0.005
0.007
0.020
0.019
0.005
0.005
<0.005
<0.005
0.021
0.010
<0.005
•=0.005
5.0
2.05
<0.005
0.029
0.031
0.012
0.023
0.003
0.010
0.052
0.039
0.031
<0.005
0.052
0.090
0.120
0.1*
marine organisms criteria .
# Secondary standards proposed for drinking water
criteria (EPA).
(continued)
-------
TABLE 11 (continued)
Material
Sllty sand
No liner
Total liner
Tl6
DCA-1295
Dynatech
0ni royal
Aerospray 70
ACkO
Asphaltic Concrete
Sucoat
Clayey silt
Guartec UF
Cement
KL79
Lime
TACSS 020
Cement /Lime
TACSS 025
citoo
CST
Values obtained from
Ref. 9 and 10
ID
No.
011B
012B
021B
022B
031B
032B
OUlB
Ol(2B
051B
052B
06lB
062B
071B
072B
091B
098B
131B
132B
2-UOO
OBlB
082B
101B
102B
111B
112B
121B
122B
lit IB
lU2B
151B
152B
l6lB
162B
171B
172B
181B
182B
NOTE: Chemical insufficient, could
* E = Equipment being
repaired.
Lead
Pb
0.005
<0.003
<0.003
<0.003
<0.003
0.005
0.006
0.016
0.008
<0.003
<0.003
<0.003
0.005
0.017
< 0.003
0.005
<0.003
0.005
0.01(8
0.030
<0.003
0.009
0.009
0.007
0.006
<0.003
<0.003
<0.003
0.022
<0.003
O.Ollt
0.0lt2
0.0li5
0.007
0.05
not be
t — = Insufficient sample to analyze
* Secondary standards
S Irrigation criteria,
proposed
»
Selenium
Se
E*
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
<0.003
E«
E»
<0.003
0.005
E«
E*
< 0.003
< 0.003
E«
<0.003
<0.003
E*
E«
<0.003
<0.003
<0.003
<0.003
<0.003
O.OOlt
0.005
<0.003
<0.003
0.01
determined.
Zinc
Zn
0.016
0.002
0.001
<0.001
< 0.001
0.002
<0.001
0.00k
<0.001
<0.001
0.002
<0.001
0.005
0.005
0.00k
0.006
0.009
0.026
2.79
2.26
< 0.001
0.005
0.007
0.001
<0.001
0.001
0.001
0.00k
0.002
0.001
0.002
0.021
0.003
0.003
5.0*
Sulfite
SO^
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
1.0
1.0
<1.0
<1.0
1.0
<1.0
<1.0
<1.0
1.0
1.0
<1.0
<1.0
in.i
12.0
<1.0
<1.0
1.0
1.0
1.5
1.0
38. U
<1.JD
5-0
22.8
1U0.6
365.0
10.0
25.0
n/a
Sulfate
SO.
297.0
1510.0
1280.0
1230.0
167.0
11(90.0
910.0
1300.0
t
1520.0
530.0
226.0
3k2.0
3kO,0
1500.0
U9i».0
872.0
36.0
100.0
92.0
117.0
1750.0
1560.0
19H.O
833.0
31(0.0
570.0
k.O
20.0
570.0
1290.0
1(560.0
29.0
21.0
250.0
Boron
B
T.k
1(6.1
35.6
32.9
3.8
28.2
18.8
kk.O
22.5
33.2
13.8
U.3
2.7
2.1
37.8
8.8
0.8
0.6
28.0
37-5
0.3
21.6
10.7
0.3
0.3
6.1
18.6
O.lt
O.U
25. k
ks.k
l.k
0.3
0.3
0.75§
Chloride
CI
78.0
20k.f
200.2
229.0
135.0
135.0
170.9
208.9
— t
18.1.5
95.0
135.9
73.0
50.0
227.9
1.6k. 6
68.0
79.0
685.7
597.8
151.0
U23.0
580.2
150.0
153.0
622.U
736.lt
19.lt
29.1
379.9
61t3.5
U62.1
77.7
71.9
250.0*
Vanadium
V
0.018
0.036
0.030
0.031
0.013
0.03U
0.027
0.037
O.Qk2
O.Okk
0.021
0.013
0.025
0.019
O.OU5
0.02!*
0.027
0.005
0.500
0.565
0.013
o.oks
0.039
< 0.005
0.018
O.Oltl
o.oue
0.006
0.006
0.056
0.090
0.271
0.007
0.008
n/a
Nitrogen
Hitrite
H02j N
31.6
<0.01
0.12
<0.01
0.30
•'O.Ol
<0.01
<0.01
— t
<0.01
<0.01
<0.01
0.66
<0.01
<0.01
0.02
<0.01
<0.01
CI
CI
0.05
<0.01
<0.01
0.07
O.Olt
<0.01
<0.01
0.15
0.03
<0.01
<0.01
<0.01
0.57
0.37
10.0
Nitrogen
Hitrate
HO^, H
1(7.5
* 0.11
0.08
<0.05
<0.05
0.26
<0.05
<0.05
— t
<0.05
0.10
0.12
l.ltl
0.31
0.30
k.82
<0.05
<0.05
CI
CI
•=0.05
0.11
0.12
<0.05
<0.05
0.26
0.38
<0.05
<0.05
<0.05
0.97
•=0.05
0.15
0.27
10.0
for all parameters .
for drinking water
criteria
(EPA).
-------
TABLE 12. SPECIFIC CONDUCTANCE AND pH VALUES
ID
No.
Oil*
012
021
022
031
032
3£
051
052
061
062
071
072
091
092
131
132
081
082
101
102
Sludge A
Sludge B
Liner Specific Conductance Specific Conductance
Material ymhos/cm pH ymhos/cm pH
Silty sand
(no liner)
Total liner
Tl6
DCA-1295
Dynatech
Uniroyal
Aero spray 70
ACl*0
Asphaltic concrete
Sue oat
Clayey silt
(no liner)
Gfuartec UF
Cement
ll*23
2525
2658
2729
1683
2101*
2020
2623
2885
1683
2805
1712
t
1578
t
3367
t
171*1
1507
721
n/a
n/a
3150
11+85
7-33
7.59
7.18
7.16
7.86
7-51
7-70
7.50
7-99
7.^6
7.80
t
7.30
7.1*8
t
7.61*
7.83'
7.^2
n/a
n/a
11.65
11.13
161*2
3061
2928
2729
t
1263
2805
2195
2805
3015
1507
1629
3061
1683
3206
2101*
1870
t
652
n/a
n/a
1*810
1*698
8.18
7-^3
7.81
7.60
t
7.96
7.36
7-1*!
7.60
5.1*3
7 = 99
7.67
7.36
7.76
7.30
7.50
7.72
t
7.39
n/a
n/a
7.85
8.16
NOTE: 1. California Consumer-Acceptance Limits (1972) recommend a specific
conductance of 800 with an upper limit of 1600 and maximum short
term of 21*00 ymhos/cm.
2. EPA water-quality criteria for Marine Aquatic Life require the
pH range to be from 6.5 to 8.5.
* The A (e.g., 011A) values are in the column headed Sludge A and
the B (e.g., 011B) are in the column headed Sludge B.
t Insufficient leakage for test.
* Insufficient sample.
(continued)
1*8
-------
TABLE 12 (continued)
ID
No.
Ill
112
121
122
ll+l
ll+2
151
152
l6l
162
171
172
181
182
Sludge
A
Sludge B
Liner Specific Conductance Specific Conductance
Material ymhos/cm pH umhos/cm pH
M179
Lime
TACSS 020
Cement /lime
TACSS
ci+oo
CST
1+391
3885
2730
211+9
3675
2928
2525
180U
31+83
2886
*
*
1+810
3607
7.83
7.69
11.71
11.29
7.22
7.50
11.50
10.1+1
7.28
7.27
*
*
11.20
9.57
1+810
1+698
3156
3156
371+1
i+oi+o
11+1+3
191+2
3258
1+122
191+23
#
5050
1+591
7.85
8.16
11.85
11.73
7.1+0
7.28
9.08
7 = 92
7.66
7-19
12.00
*
9-35
9.30
* Insufficient sample.
first 32-oz sample submitted for analysis. The composition or amount of addi-
tional water is not directly determinable, and it varied with the nature of
the liner and the application rate of liner material.
During the testing of the liner materials, the simulated head (compressed
air) was forcing the liquid or liquor associated with the FGD sludges through
the liner and into the soil. Two different FGD sludges were used in this
testing program, but the liquids associated with them were quite close in
composition. The liquid was alkaline (pH 9-10.3) and saturated with gypsum
and calcium carbonate. The chemical compositions of these liquids are given
in Tables 10 and 11.
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SECTION 9
ANALYSIS AND DISCUSSION OF RESULTS
This section presents the results of the project at the midpoint of the
study. The discussion includes results of physical tests and chemical analy-
ses at the initial stage (zero time) and at the end of the 12-month exposure
period.
PHYSICAL TESTS
General
In reviewing the physical test data, the three types of liner materials
should be kept in mind: admixed materials, spray-on materials, and prefabri-
cated membrane materials. Unconfined compression tests (6) were used to study
the effects of 12-month inundation/pressurization of the admixed liners,
whereas grab tests (7) were employed to study similar effects on the spray-on
and prefabricated membrane liners. Neither of these tests would yield very
meaningful data for asphaltic concrete or asphalt cement liners. Tests of
these two liner materials were concentrated on the asphalt cement itself..
Density, penetration, and viscosity of the asphalt cement were determined as
a means of ascertaining deterioration.
Admix Liners
The results of the physical tests on the admix liners are shown in
Table 8. The results shown are for both the zero and 12-month exposure times.
Two of the materials, Guartec UF and M1795 were obviously incompatible with
either of the sludges as a complete breakdown of the liners occurred. The two
materials are considered unsatisfactory for the stated use, and further tests
have been discontinued. The moisture content in all samples increased
slightly, indicating some liquid infiltration, although the dry density re-
mained about the same during the 12-month period, which would indicate that
the soil structure was not changed. Five of the materials, Portland cement,
lime, Portland cement plus lime, C^OO, and GST, exhibited considerable in-
creases in unconfined compressive strengths. The strength in general almost
doubled; however, in the lime admix, the strength increased almost six times
the initial strength.
Normally, at least in the case of silty clay stabilized with 10 percent
lime, the UC strength can be observed to increase from 150 psi after a 7-day
cure to approximately UOO psi after 36 weeks cure (1*0. Undoubtedly, other
soil types would also have similar UC versus cure time curves with greater
UC values. Although very little is known about the Cl+00 and CST materials,
50
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they were reported to be very similar to cement with additional additives.
These unusually high strengths vill be closely compared with the 2^-month
data.
A photo series (Figures l6, IT, and 18) of the asphaltic concrete liner
shows two extensive surface cracks (Figure l6). Covering the liner with
water and applying back pressure only produced bubbles at the intersection of
the two cracks (Figure 17). A close-up of this liner shows the relative size
of the two cracks (Figure 18).
Figure 16. Asphaltic concrete liner
surface showing extreme cracking.
Figure IT. Asphaltic concrete liner with sludge
removed, approximately 1-in. water added, and 2-psi
back pressure applied.
-------
Figure 18. Close-up of cracks in asphaltic con-
crete liner. Discolored area around periphery indi-
cates area covered by silicone sealant.
TACSS 020 and 025 "both suffered 5 to 25 percent decrease in UC, which
would seem to indicate some degree of susceptibility to continuous exposure
that could only be expected to get worse with time. Much more can be deter-
mined when the 2^-month test results are analyzed.
Spray-on and Prefabricated Membrane Liners
The results of the physical tests on the spray-on and membrane liners
are shown in Table 9- Without exception, the breaking strengths of the liners
decreased with exposure time. The percent elongation varied somewhat; it
increased significantly for total liner and decreased significantly for
DCA-1295 and Aerospray TO. It remained essentially constant for Tl6,
Dynatech, and Uniroyal. Figure 19 shows DCA-1295 and Uniroyal after 12-month
grab tests. The ACUo test cells did not pass any liquid until two-thirds of
the way through the test period. Following teardown, a hole was observed in
one liner near the center. The liner fell apart while it was being removed
from the test cell. No zero data have been obtained for the Sucoat liner
materials, and one test cell ruptured during the 12-month period. Wo evidence
of chemical attack could be observed on the one remaining liner. Figure 20
shows the prefabricated membrane total liner after 12-month grab test.
CHEMICAL TESTS
The initial permeate .water sarrrnles taken during this testing program also
may contain any leachable constituents from the liners. In many cases, the
effects of material lost from the liners cannot be seen because of the very
concentrated liquor from the FGD sludges and normal background chemistry of
the water associated with the soils. There are, however, some exceptions.
For example, Guartec, an organic product derived from the guar bean, obvi-
ously decomposed and became putrescent. The resulting reducing conditions
appear to have released manganese, or caused manganese in the soil to go into
52
-------
a. DCA-1295
b. Uniroyal
Figure 19. Spray-on liner materials samples fol-
lowing 12 months of inundation and grab test,
53
-------
Figure 20. Prefabricated membrane total
liner material samples following 12 months
of inundation and grab test.
solution. The manganese levels in the liquid from the Guartec UF test cells
are an order of magnitude greater than those of other test cells. This oc-
curred in all sets of test cells with both Sludges A and B. Guartec UF,
along with TACSS 020 and TACSS 025, released levels of magnesium higher than
observed in other samples. Locally, acidic conditions may have developed in
these admixes due to decay (in the case of Guartec UF) or reactions with
plasticizers (in the case of TACSS 020 or TACSS 025).
The first 32 oz of water collected from each test cell represents the
first liquid that would be passing down into the saturated zone and mixing
with the groundwater. This initial contribution arriving at the water table
is a mixture of sludge liquor, materials from the liner, and displaced inter-
stitial water (pore water) from the soil. The extent of mixing of the con-
centrated solution from the sludge and soil water is directly related to the
location of the soil mass that is invaded by the infiltrating sludge liquor.
The leakage from a email rupture in a test membrane will seep directly
through the soil under the leak (Figure 21a), and by displacing only small
amounts of soil pore water, will have a composition near to that of the sludge
liquor plus any contaminants from the membrane. For a test cell with no mem-
brane or with a membrane passing liquid over a broad area, a shallower mass
of soil is invaded initially, and the first liter of liquid reaching the test
cell outlet is primarily displaced soil pore water (Figure 21b). Thus, if
the membrane passes water over the entire cross section of the test cell and
sludge liquor moves through the entire soil/sludge interface, the initial per-
meated water sample will be very close to pore water in composition. The con-
figuration of the leak by which sludge liquor passes through the membrane is
probably the most decisive factor in determining the composition of the
initial 32-oz water sample.
-------
COMPRESSED
AIR
SMALL
BREAK IN
MEMBRANE
COMPACTED
SOIL
SATURATED SLUDGE
POND LIQUOR
SLUDGE
PORTION OF SOIL
INVADED BY POND
LIQUOR.
I
INITIAL SAMPLE IS ONLY SLIGHTLY
DILUTED POND LIQUOR
a. Small rupture in membrane.
COMPRESSED
AIR
NO EFFECTIVE
MEMBRANE
COMPACTED
SOIL
SATURATED SLUDGE
POND LIQUOR
SLUDGE
PORTION OF SOIL
INVADED BY POND
LIQUOR
INITIAL SAMPLE PRIMARILY SOIL WATER
DISPLACED BY POND LIQUOR
b. Large rupture in membrane.
Figure 21. Pattern of leakage from membrane ruptures.
55
-------
The concentration of a chemical constitutent such as chloride, which is
not effectively attenuated by soil, is an important indicator of how the
sludge liquor is moving through the membrane. Tables 13 and 1^ list the
liners in order of increasing chloride content from initial permeate water
samples. The spray-on liners AC^O and Sucoat both show low chloride levels in
the intial liquid samples from Sludges A and B, suggesting that liquid was
moving through the membrane along the entire cross section of the test cell.
This hypothesis is borne out by observations made on the condition of the
liners after the 12-month exposure. The ACUO liner developed a large leak in
the center and had deteriorated so badly that it could not be removed intact
from the test cell. The Sucoat liner had fractured and too little material
was available for postexposure testing. In the admixed materials, the
cement/lime and GST liners show very low chloride levels with Sludges A and B,
again suggesting uniform permeation across the area of the test cell. Neither
of these materials showed evidence of local small leakage when the cells used
for 12-month exposure were examined.
As liquor continues to pass through these liner materials, the composi-
tion of the discharge from the test cells will approach the composition of the
sludge liquor. In a typical sludge pond situation the decomposition products
from the liner should be a minor problem compared to the high levels of pollu-
tants in the ponded sludges. This study indicates that the characteristics of
the leak are an important facet of the initial effect of the contained sludge
liquor on the groundwater. However, if the liner fails, ultimately the full
impact of sludge contamination will be felt.
TABLE 13. LINER MATERIALS ON SILTY SAND LISTED IN ORDER
OF INCREASING CHLORIDE CONTENT
Liner
Material
Test Cells for
Sludge A
Avg Cl, ppm
Liner
Material
Test Cells for
Sludge B
Avg Cl, ppm
ACliO
Sucoat
No liner
Total liner
Aerospray 70
Uniroyal
DCA-1295
T16
Dynatech
Asphaltic concrete
Sludge liquor
62
65
83
102
109
176
190
212
21 k
675
AChO
Sucoat
No liner
Aerospray 70
DCA-1295
Uniroyal
Dynatech
Asphaltic concrete
Total liner
Tl6
Sludge liquor
62
68
78
115
135
182
190
196
202
221+
670
56
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TABLE Ik. LINER MATERIALS ON CLAYEY SILT LISTED IN ORDER
OF INCREASING CHLORIDE CONTENT
Liner
Material
Cement/lime
CST
Lime
No liner
Cement
TACSS 025
M179
TACSS 020
Sludge liquor
Guartec UF
Test Cells for
Sludge A
Avg Cl, ppm
17
38
U5
95*
1U2
U2U
1+37
^95
675
1117
Liner
Material
Cement /lime
CST
No liner
Cement
Lime
ckoo
M179
TACSS 025
Guartec UF
Sludge liquor
TACSS 020
Test Cells
Sludge
Avg Cl,
2k
75
79*
151
152
U62*
502
512
670
679
for
B
pnm
* Single sample.
57
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REFERENCES
1. U. S. Environmental Protection Agency. Report to Congress on Hazardous
Waste Disposal. SW-115, Cincinnati, Ohio, 1973.
2. Haxo, H. E., and R. M. White. First Interim Report, Evaluation of Liner
Materials Exposed to Leachate (unpublished). U. S. Environmental Protec-
tion Agency, Cincinnati, Ohio, 197^-•
3. Haxo, H. E., and R. M. White. Second Interim Report, Evaluation of Liner
Materials Exposed to Leachate. EPA-600/2-76-255, U. S. Environmental
Protection Agency, Cincinnati, Ohio, 1976.
^
U. Haxo, H. E., R. S. Haxo, and R. M. White. First Interim Report, Liner
Materials Exposed to Hazardous and Toxic Sludges. EPA-600/2-77-08l,
U. S. Environmental Protection Agency, Cincinnati, Ohio, 1977-
5. Geswein, A. J. Liners for Land Disposal Sites, An Agreement.
EPA-530/SQ-137, U. S. Environmental Protection Agency, Cincinnati, Ohio,
1975.
6. American Society for Testing and Materials. Tests for Unconfined Compre-
hensive Strength of Cohesive Soils. In: 1978 Annual Book of ASTM
Standards, Part 19, Designation: D 2166-66, Philadelphia, Pennsylvania,
1978.
7. American Society for Testing and Materials. Tests for Breaking Load and
Elongation of Textile Fabrics. In: 1978 Annual Book of ASTM Standards,
Part 32, Designation: D 1682-6U, Philadelphia, Pennsylvania, 1978.
8. Mahloch, J. L., D. E. Averett, and M. J. Bartos, Jr. Pollutant Potential
of Raw and Chemically Fixed Hazardous Industrial Wastes and Flue Gas
Desulfurization Sludges. EPA-600/2-76-182, U. S. Environmental Protec-
tion Agency, Cincinnati, Ohio, 1976.
9. Tate, C. H., and R. R. Trussell. Developing Drinking Water Standards.
Journal of the American Water Works Association, 69(9): U89-^92, 1977-
10. Quality Criteria for Water. EPA-l^O/9-76-023, U. S. Environmental
Protection Agency, Cincinnati, Ohio, 1976, 500 pp.
11. Department of the Army. Engineer Manual EM 1110-2-1906: Laboratory
Soils Testing. Prepared by U. S. Army Engineer Waterways Experiment
Station, CE, Vicksburg, Mississippi, 1970
58
-------
12. Wilson, S. D. Small Soil Compaction Apparatus Duplicates Field Results
Closely. Soil Testing Services, Inc., Chicago, Illinois (undated
brochure).
13. Styron, C. R., III, and R. C. Eaves. Investigation of Dust-Control
Materials. Prepared by U. S. Army Engineer Waterways Experiment Station,
CE, Vicksburg, Mississippi, 1973.
iH. Yoder, E. J., and M. W. Witczak. Principles of Pavement Design.
John Wiley and Sons, Inc., New York, 1975.
59
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APPENDIX A
MANUFACTURER/ADDRESS FOR THE SELECTED LITTER MATERIALS
Material
Manufacturer/Address
Type I Portland Cement
Hydrated Lime
Cement with Lime
M1T9
Guartec UF
Asphaltic Concrete
TACSS 020
TACSS 025
CkOO
CST
DCA-1295
Dynatech Formulation 26j
Uniroyal
Aerospray 70
ACUO
Sueoat
Total liner
T16
Local Distributor
Local Distributor
Local Distributor
Dowel Division of Dow Chemical
General Mills
Local Contractor
Takenaka Komuten Co. (Japan)
Takenaka Komuten Co. (Japan)
Takenaka Komuten Co. (Japan)
Takenaka Komuten Co. (Japan)
Union Carbide
Dynatech R&D Co.
Uniroyal Inc.
American Cyanamid
Globe Asphalt
Chevron Chemical Co.
Goodyear Tire & Rubber Co.
Reeves Brothers, Inc.
60
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/2-79-136
2.
3. RECIPIENT'S ACCESSION-NO.
TITLE AND SUBTITLE
FLUE GAS CLEANING SLUDGE LEACHAT.E/
LINER COMPATIBILITY INVESTIGATION
Interim Report
5. REPORT DATE
August 1979 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Clarence R. Styron III and Zelma B. Fry, Jr,
PERFORMING ORGANIZATION NAME AND ADDRESS
Geotechnical Laboratory
U.S. Army Engineer Waterways Experiment Station
Vicksburg, Mississippi 39180
10. PROGRAM ELEMENT NO. 1QC318
SOSl.Task27qNE624.COS.SOX 4
11. CONTRACT/GRANT NO.
IAG-D5-0785
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 April 15-September 77
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Robert E. Landreth (513) 684-7871
16. ABSTRACT
This project was initiated to study the effects of two industrial waste materials
on 18 items used to contain these wastes. Seventy-two test cells, 1 ft in diameter
and 2 ft high, were fabricated. Ten items were mixed with a clayey silt and com-
pacted in the bottom 6 in. of the test cell; six spray-on and two prefabricated
membrane items were placed over 6 in. of compacted soil. Four gallons of sludge
were added to each test cell and enough tap water to bring the liquid to within
4 in. of the top of the test cell. Each test cell was covered and pressurized to
simulate 30 ft of head.
This report lists and discusses the data following 12 months of inundation of each
item with both sludges. Portland cement, cement plus lime, and C400 when mixed with
the soil resulted in a significant reduction in permeability.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
cos AT I Field/Group
Linings
Permeability
Waste Disposal
Air Pollution
Electric Power Generation
Sludge
Soil Sealants
Emission Control
Membrane Liners
Solid Waste Management
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
,GES
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
61
* U.S. GOVERNMENT PRINTING OFFICE: 1979 -6 57 -06 0 / 5 410
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