MANAGEMENT OF
GAS AND LEACHATE
N LANDFILLS
EPA-600/9-77-026
September 1977
Proceedings of the Third Annual Municipal Solid Waste
Research Symposium
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati. Ohio 45268
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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 document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/9-77-026
September 1977
MANAGEMENT OF GAS AND LEACHATE IN LANDFILLS
Proceedings of the Third Annual Municipal Solid Waste Research Symposium
held at St. Louis, Missouri, March 14, 15 and 16, 1977, and
Co-sponsored by the U.S. Environmental Protection Agency,
Solid and Hazardous Waste Research Division, and by the
Department of Civil Engineering, University of Missouri—Columbia
Edited by Shankha K. Banerji
Department of Civil Engineering
University of Missouri
Columbia, Missouri 65201
Project Officers
Robert E. Landreth
Solid and Hazardous Waste Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
Morris G. Tucker
U.S. Environmental Protection Agency
Region VII
Kansas City, Missouri 64108
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
These Proceedings have been reviewed by 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. Environ-
mental Protection Agency, nor does mention
of trade names or commercial products consti-
tute endorsement or recommendation for use.
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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 our natural environment. The complexity of the environment
and the interplay between its components require a concentrated and integrated
attack on the problem.
Research and development is the necessary first step in problem solution and it
involves defining the problem, measuring its impact, and searching for solutions.
The Municipal Environmental Research Laboratory develops new and improved technology
and systems for the prevention, treatment, and management of wastewater and solid
and hazardous waste pollutant discharges from municipal and community sources, for the
preservation and treatment of public drinking water supplies, and to minimize the
adverse economic, social, health and aesthetic effects of pollution. This publication
is one of the products of that research; a most vital communications link between the
researcher and the user community.
The proceedings identifies research aimed at management of gas and leachate
formed in sanitary landfills and provides solutions to these unique problems.
Francis T. Mayo
Director
Municipal Environmental
Research Laboratory
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ABSTRACT
The symposium proceedings are primarily intended to disseminate up-to-date infor-
mation on extramural research on gas and leachate formation, collection and management
in sanitary landfills funded by the Solid and Hazardous Waste Research Division (SHWRD),
U.S. Environmental Protection Agency, Municipal Environmental Research Laboratory in
Cincinnati, Ohio. Selected papers from work of other organizations were included in the
symposium to identify closely related work not included in the SHWRD program.
The proceedings should be of value to researchers, designers, planners, and
governmental agencies to select and manage landfill sites that will prevent environ-
mental contamination from leachate and gas production.
iv
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CONTENTS
Page
Disclaimer ................................... ^
Foreword .................................... ^ i i
Abstract .................................... 1v
Contents .................................... v
Acknowledgment ................................. v^i
SESSION I:
Current Research on Land Disposal of Municipal Solid Wastes
Norbert B. Schomaker, U.S. Environmental Protection Agency .......... 1
Summary of Office of Solid Waste Gas and Leachate Activities
Truett V. DeGeare, Jr., U.S. Environmental Protection Agency ......... "13
State of Missouri Solid Waste Management Activities
Robert M. Robinson, Missouri Department of Natural Resources ......... 18
Region VII Solid Waste Activities
Morris G. Tucker, U.S. Environmental Protection Agency .... ........ 22
Landfill Research Activities in Canada
Hans Mooij, Fisheries and Environment Canada ................. 25
SESSION II:
The Effects of Industrial Sludges on Landfill Leachates and Gas
David R. Streng, Systems Technology Corporation ............... 41
Influence of Municipal Solid Waste Processing on Gas and Leachate Generation
Melvin C. Eifert and Joseph T. Swartzbaugh, Systems Technology Corporation . . 55
Effect of Moisture Regimes and Other Factors on Municipal Solid
Waste Stabilization
E.S.K. Chian and E. Hammerburg, University of Illinois
F. B. DeWalle, Stanford University ...................... 73
SESSION III:
Leachate Production and Viral Survival from Landfilled Municipal Solid Waste
Dirk R. Brunner and Arthur W. Bales, U.S. Environmental Protection Agency
R. Wigh, Regional Services Corporation ................ .... 87
Design Criteria for Gas Migration Control Devices
Charles A. Moore and Igbal S. Rai, Ohio State University ........... 88
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Page
Modeling of Leachate and Soil Interactions in An Aquifer
M. van Genuchten, G. F. Pinder and W. P. Saukin, Princeton University .... 95
Aerial Detection Techniques for Landfill Pollutants
Warren R. Phillipson and Dwight A. Sangrey, Cornell University ........ 104
Pollutant Migration Patterns from Landfills
0. L. Mahloch, B. L. Folsom, Jr., 0. M. Brannon, J. D. Broughton and
J. H. Shamberger, U.S. Army Engineer Waterways Experiment Station ...... 115
Land Disposal Criteria and Compliance Monitoring Relative to
Leachate and Ground Water
Kenneth A. Sinister, U.S. Environmental Protection Agency ........... 123
Attenuation of Leachate Pollutants by Soils
Mike H. Roulier, U.S. Environmental Protection Agency ............ 127
Effect of Municipal Landfill Leachate on the Release of Toxic
Metals from Industrial Waste
M. J. Houle, D. E. Long, R. E. Bell, J. E. Soyland, and R. R. Grabbe
U.S. Army Dugway Proving Grounds ....................... 139
SESSION IV:
Compatibility of Liners with Leachate
Henry E. Haxo, Jr., Matrecon, Inc ................. . ..... 149
Predicting Cadmium Movement through Soil as Influenced by Leachate
Characteristics
D. F. O'Donnell, B. A. Alesii, J. Artiola-Fortuny and W. H. Fuller
University of Arizona ............................ 159
Analytical Methods for Leachate Analysis
Richard A. Carnes, U.S. Environmental Protection Agency ........... 173
Leachate Treatment of Biological and Physical -Chemical Methods -
Summary of Laboratory Experiments
F. B. DeWalle, Stanford University, and E.S.K. Chian, University of Illinois . 177
Leachate Treatment by Soil Methods
Grahame J. Farquhar, University of Waterloo ................. 187
Attenuation of PCB's by Soil Materials and Char Wastes
R. A. Griffin and A. K. Au, Illinois State Geological Survey
E.S.K. Chian and J. H. Kim, University of Illinois
F. B. DeWalle, Stanford University ...................... 208
SESSION V:
Vegetation Kills in Landfill Environs
F. B. Flower, I. A. Leone, E. F. Gilman, J. J. Arthur,
Rutgers University .............................. 218
Effects on Soils and Plants from Applications of Composted Municipal
Solid Waste - A Summary of Selected Research Projects
Carlton C. Wiles, U.S. Environmental Protection Agency ............ 237
VI
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Page
Land Cultivation of Municipal Solid Waste
Tan Phung and David Ross, SCS Engineers
Robert Landreth, U.S. Environmental Protection Agency 259
Implications of Price Incentives for Solid Waste Management
Oscar W. Albrecht, U.S. Environmental Protection Agency 268
Effects of Decomposition Gases on Landfill Revegetation at
TVA's Land Between the Lakes
J. Carroll Duggan and David H. Scanlon,
Tennessee Valley Authority 275
List of Attendees 279
vn
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ACKNOWLEDGMENT
In addition to the contributors to these proceedings, the help
of the following session chairmen is gratefully acknowledged:
Norbert B. Schomaker, Dirk R. Brunner, Mike H. Roulier, Robert
E. Landreth and Richard A. Carnes (U.S. Environmental Protec-
tion Agency, Cincinnati, Ohio). Special appreciations are due
to Everett Walters, UMSL Vice Chancellor and Francis T. Mayo,
Director, Municipal Environmental Research Laboratory, U.S.
Environmental Protection Agency, Cincinnati, Ohio for welcoming
the participants. Thanks are also due to Phillip A. Lincoln,
Engineering Extension, UMC, for editorial assistance; Patricia
Young for the cover design; W. J. Thomas and Nicholas Palo,
Engineering Extension, UMC for help in organizing the symposium.
In addition, the help of the project officers Robert Landreth
and Morris G. Tucker is also acknowledged.
VTM
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CURRENT RESEARCH ON LAND DISPOSAL OF MUNICIPAL SOLID WASTES
Norbert B. Schemaker
U.S. Environmental Protection Agency
26 West St. Clair Street
Cincinnati, Ohio 45268
ABSTRACT
The Solid and Hazardous Waste Research Division (SHWRD), Municipal Environmental
Research Laboratory, U.S. Environmental Protection Agency, in Cincinnati, Ohio, has re-
sponsibility for research in the areas of municipal solid and hazardous waste management,
including both disposal and processing. This research is being directed towards new and
improved systems of municipal solid and hazardous waste management, development of tech-
nology, determination of environmental effects, and collection of data necessary for the
establishment of processing and disposal guidelines.
Division activities in the area of municipal solid waste research have related to
storage, collection, transport, processing, resource recovery, and disposal. Recent
emphasis on energy has resulted in an expansion of the waste-as-fuels program.
The current municipal solid waste disposal research program has been divided into
three general areas: (1) Pollutant Predictions for Current Landfill Techniques, (2)
Alternatives to Current Landfill Disposal Techniques, and (3) Remedial Action for Min-
imizing Pollutants from Unacceptable Sites.
The research activites currently funded under these three general areas have been
classified into seven categories shown below:
1. Residual Characterization/Decomposition
2. Pollutant Transport
3. Pollutant Control/Treatment
4. Co-disposal
5. Environmental Assessment
6. Remedial Action
7. Landfill Alternatives
INTRODUCTION
Increasing amounts of waste residuals
are being directed to the land for disposal
in landfills. At the same time, there is
increasing evidence of environmental damage
resulting from improper operation. The
burden of operating landfills and coping
with any resulting damages falls most
heavily on municipalities and other local
government agencies. Their problems are
complex, involving legislation, economics,
and public attitudes as well as technology;
additionally, comprehensive information on
landfill ing techniques and protect ion of
the local environment is not readily
available.
Current estimates indicate that 144
million tons (as generated with moisture)
of municipal wastes and 260 million tons
(dry) of industrial wastes are disposed of
to the land. A survey of national solid
waste management practices conducted in
1968 by the Federal government through
cognizent state agencies indicated less
than 6 percent of 6000 land disposal sites
surveyed could be considered sanitary
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landfills, based on very modest criteria
not including a re-evaluation of ground-
water pollution. More recent surveys (in
1975 and 1977) indicated a 25 percent in-
crease over a 2-year period in the num-
ber of disposal sites considered to be
sanitary landfills (5740 of 15,821 sites
in 1976). The total number of disposal
sites appears to have increased greatly
since 1968, but this can be explained, in
part by better record keeping by state
agencies and/or that environmental
enactments have both severely restricted
refuse disposal by burning or dumping at
sea and greatly increased the amount of
solid waste generated as residues from
air and water cleaning operations. The
most pernicious effect of unsound disposal
is the contamination of groundwater by
leachate; about half of the United States
domestic water supply is from groundwater.
Groundwater contamination is usually dis-
covered long after the damage is done and
too late for corrective measures.
The municipal waste disposal program
initiated by SHWRD was designed to docu-
ment and evaluate the potential adverse
environmental and public health effects
that could result from application of
waste disposal methods without proper
precautions for leachate and gas manage-
ment. The information thus obtained will
provide the necessary data for the estab-
lishment of guidelines for communities
to develop economical and environmentally
safe municipal waste disposal management
systems.
Specifically, in the area of landfill
disposal techniques, a comprehensive data
base on the characteristics of municipal
and hazardous wastes will be developed to
assess pollutants within a waste residual,
pollutant release from waste residuals in
the form of leachates and gas, decomposi-
tion rates under varying moisture regimes,
the migration and attenuation of pollu-
tants, and the resultant environmental
damages. In addition, liner materials,
both natural and synthetic, and chemical
stabilization techniques for controlling
leachate movement will be investigated.
Research efforts will be conducted pri-
marily through laboratory and pilot
studies with some field testing of
laboratory-based results.
In the area of alternative land
disposal methods, technical and environ-
mental data will be obtained to provide
a basis for logical engineering decisions
on viable environmentally sound methods
other than landfill.
In the area of remedial action for
preventing pollutant generation from un-
acceptable landfill sites, an engineering
feasibility and design plan will be de-
veloped and tested in a field veri-
fication study.
This research strategy, encompassing
state-of-the-art documents, laboratory
analysis, bench and pilot studies, and
full-scale field verification studies, is
at various stages of implementation, but
over the next 5 years the research reports
developed will be compiled as criteria
and guidance documents for user communi-
ties. Also, the waste disposal research
program will develop and compile a re-
search criteria data base for use in the
development of guidelines and standards
for waste residual disposal to the land
as mandated by the recently enacted
legislation entitled "Resource Conser-
vation and Recovery Act of 1976" (RCRA).
RESIDUAL CHARACTERIZATION/DECOMPOSITION
Studies in this area involve collect-
ing composition data on municipal and
hazardous wastes from individual waste
residuals and landfill disposal sites.
Sampling techniques, analytical methods/
procedures, and waste compatibility and
waste decomposition information will be
developed for implementing better disposal
practices and waste management.
The objectives of this research
activity are to (1) quantify the gas and
leachate production from current best-
practice, sanitary landfill ing and (2)
modify the landfill method to reduce the
environmental impact of gas and leachate
production in a positive and predictable
manner. These objectives are to be
achieved by construction and long-term
monitoring of typical and simulated land-
fill cells and investigation, development,
and optimization of those factors that
control gas and leachate production.
Results are expected only after long-term
monitoring, due to the extremely slow
reaction rates.
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Several previous reviews of these
efforts have been presented. See
Schomaker, N.B. and Roulier, M. H., Cur-
rent EPA Research Activities in Solid
Waste Management: Research Symposium
on Gas and Leachate from Landfills:
Formation, Collection and Treatment,
March 25-26, 1975, Rutgers, State Univer-
sity of New Jersey; and Schomaker, N. B.,
Current Research on Land Disposal of
Hazardous Wastes: Residual Management
by Land Disposal: Proceedings of the
Hazardous Waste Research Symposium,
February 2-4, 1976, University of Arizona.
Standard Analytical Techniques
Analysis of the contaminants within
a waste leachate sample is difficult due
to interfering agents. Existing instru-
mentation functions well in the analysis
of simple mixtures at low concentrations
but interference problems can be en-
countered for complex mixtures at high
concentrations (1 percent by weight and
greater). In this range the sample can-
not always be analyzed directly and
commonly must be diluted and/or analyzed
by the method of standard additions.
Options are the development of standard
procedures for diluting and accounting
for errors introduced thereby or the
development of instrumentation capable
of accurate, direct measurements at high
concentrations in the presence of po-
tential multiple interferences. Existing
USEPA procedures for water and wastewaters
are often not applicable. Analytical pro-
cedures are being developed on an as-needed
basis as part of the SHWRD projects. How-
ever, most of this work is specific to the
wastes being studied and separate efforts
were required to insure that more general
procedures/equipment would be developed.
A compilation of analytical techniques1*
used for contaminant analysis has been
published in a report entitled Compilation
of Methodology Used forMeasuring Pollution
Parameters of Sani tary Landfi11 Leachates,
EPA-600/3-75-011, October 1975, and SHWRD
*Superscript numbers refer to the project
officers, listed immediately following
this paper, who can be contacted for
additional information.
is currently conducting a collaborative
testing study2 on leachate analyses. In
this study, leachate samples will be sent
to some 40 or 50 laboratories for analysis
of specific parameters. The results will
provide information on detection limits
and precision for contaminants in leach-
ate, using currently accepted methods
developed for water and wastewater.
Standard Leaching Tests
In studying the potential environ-
mental impact of contaminants, a standard
leaching test is needed to assess con-
taminant release from a waste. Such a
test must provide information on the
initial release of contaminants from a
waste contacted not only by water but
also by other solvents that could be
introduced in disposal. Additionally,
such a test must provide some estimate
of the behavior of the waste under ex-
tended leaching. Experience from ongoing
SHWRD projects indicates that some wastes
may initially release only small amounts
of contaminants, but, under extended
leaching, will release much higher con-
centrations. Such leaching behavior has
an impact on disposal regulation and on
management of a disposal site, and in-
formation on this behavior must be ob-
tained and used in classifying a waste.
The Office of Solid Waste (OSW) has
funded the Industrial Environmental
Research Laboratory (IERL), USEPA project3
to examine this background area and de-
velop procedures for determining whether
a waste contains significant levels of
toxic contaminants and whether a waste
will release such contaminants under a
variety of leaching conditions.
Validation of a Standard Leaching
Test (SLT) is planned for future efforts,
funded in part by SHWRD.2 The passage of
the RCRA on October 21, 1976, imposing
time restraints, necessitated developing
an Interim Standard Leaching Test (ISLT).
Existing leaching tests will be evaluated
for those elements that may be of special
benefit to the development of an SLT, and
at least three candidate ISLT's will be
chosen for further testing as part of the
OSW/IERL project.
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Haste teachability
The characteristics of leachates from
municipal refuse and mixtures of municipal
refuse and selected industrial and munici-
pal sludges are being studied in several
different projects. Leaching study
results'1 for 437 tons of municipal refuse
are being compared to results of leaching
from 117-ton and 3-ton experimental land-
fills located at the Boone County Field
Site (BCFS) of USEPA. Another study,*
performed under contract at the Center
Hill Facility of USEPA, involves comparing
the characteristics of leachates obtained
from 3-ton experimental landfills con-
taining municipal refuse and selected
sludges of municipal and industrial
origin.
Results obtained from the large ex-
perimental landfill at BCFS indicated
greater removal of contaminants through
leaching than previously reported from
other experimental landfills. The test
cell, receiving approximately 21 in/yr
of net infiltration and constructed in
June of 1971, still leaches appreciable
quantities of COD (4000 mg/1), Fe (350
mg/1), total solids (4500 mg/1), and
other contaminants. Additionally, C02
and CH4 are still produced. This evalu-
ation of current disposal practices is to
be completed in FY 1980.
Leachates were also assayed for fecal
coliform and fecal streptococci. There
was an initial large number of such or-
ganisms (>106 organisms/ml) present in
the leachates, but the fecal coliform
rapidly (over several months) dropped to
low (<20 organisms/ml) levels. Fecal
streptococci have continued to be present
(103 to 106 organisms/ml) in the leachates
throughout the 5 years of operating data
at BCFS.
Survival of poliovirus in landfill ing
refuse was investigated at BCFS and the
Center Hill Facility. Studies by USEPA
showed the presence of this virus in
municipal solid waste and the presence of
the virus in leachates when the waste was
surcharged with large volumes of water.
Boliovirus-seeded refuse samples were ex-
posed to landfill conditions for 10 or
more days and no poliovirus was recovered.
The high ambient temperatures (air = 35°C;
refuse = 59°C) were assumed to be the
principal cause of virus inactivation.
No viruses were found in the leachate.
Leachate was, however, found to be
antagonistic to seeded viruses. Tempera-
ture of the leachate (5°, 10°, 15°C) was
found to be very important in determining
the rate of inactivation. The survival
of poliovirus within landfilling refuse
was repeated under different ambient
conditions (air = 0°C; refuse = 15°,
18°, and 27°C); survival was found to be
temperature dependent and 33 days after
the refuse was landfilled survival was
less than 1 percent. The viral and
bacterial efforts at BCFS have been
reported in the News of Environmental
Research in Cincinnati, "Survival
of Fecal Coliforms and Fecal Streptococci
in a Sanitary Landfill" (April 12, 1974)
and "Poliovirus and Bacterial Indicators
of Fecal Pollution in Landfill Leachates"
(January 31, 1975).
Waste Decomposition
Waste decomposition data are being ob-
tained from several ongoing efforts. One
study" is a modification of the landfill
method to accelerate waste decomposition
in a predictable manner. This study was
successfully performed on a laboratory
scale and a report entitled Sanitary
Landfill Stabilization with Leachate
Recycle and Residual Treatment. EPA-600/
2-75-043, October 1973, has been published.
Leachate recirculation with pH control re-
sults in waste decomposition in a time
period as short as 6 months. Field
application will probably yield a 1- or
2-year decomposition period due to an-
ticipated leachate distribution problems.
A second effort1* involves the
elucidation of the role of moisture re-
gime (different net infiltration condi-
tions). This study is being performed
on a laboratory scale. It will yield
valuable information with respect to
the kinetics of waste decomposition, in-
cluding CH4 volumes and production rates.
A third effort1 involves the effect
of different waste processing techniques
on gas and leachate production and duration
during waste decomposition. Raw refuse,
shredded refuse, and baled refuse are being
investigated in a simulated landfill en-
vironment. Interim results of this effort
have been previously discussed at the
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Engineering Foundation and ASCE Confer-
ence: Land Application of Residual
Materjals, held in Easton, Maryland,
September 26 to October 1, 1976, as "A
Study of Gas and Leachate Production from
Baled and Shredded Municipal Solid
Wastes."
POLLUTANT TRANSPORT
Pollutant transport studies involve
the release of pollutants in liquid and
gaseous forms from various municipal and
hazardous wastes and the subsequent move-
ment and fate of these pollutants in
soils adjacent to disposal sites. Al-
though the potential for damage in gen-
eral can be demonstrated, migration
patterns of contaminants and consequent
damages that would result from unre-
stricted landfill ing at specific sites
cannot be accurately predicted. The
ability to predict must be developed in
order to justify the requirement for
changes in the design and operation of
disposal sites, particularly for any re-
striction of co-disposal of municipal
and industrial waste. Both laboratory and
field verification studies at selected
sites are being performed to assess the
potential for groundwater contamination.
The studies will provide the information
required to (1) select land disposal
sites that will naturally limit release
of pollutants to the air and water and (2)
make rational assessments of the need for
and cost-benefit aspects of leachate and
gas control technology.
The overall objective of this re-
search activity is to develop procedures
for using soil as a predictable attenu-
ation medium for pollutants. Not all
pollutants are attenuated by soil, and, in
some cases, the process is one of delay so
that the pollutant is diluted in other
parts of the environment. Consequently,
a significant number of the research
projects funded by SHWRD are focused on
understanding the process and predicting
the extent of migration of contaminants
(chiefly heavy metals) from land disposal
sites.
These pollutant migration studies are
being performed simultaneously in the areas
of municipal refuse and specialized wastes.
Several previous reviews of these efforts
have been presented. See Roulier, M, H.,
Research on Minimizing Environmental
Impact from Landfill ing, and Research on
Contaminant Movement in Soils, both
presented at a meeting of the NATO
Committee for Challenges to Modern
Society. Project Landfill, October 22-23,
1975, London, England.
Bibliography and State of the Art
A state-of-the-art document on
migration through soil of potentially
hazardous pollutants contained in
leachates5 from waste materials has been
published, Movement of Selected Metals,
Asbestos, and Cyanide in Soi1s: Applica-
tions to Haste DisposalProblems, EPA-
600/2-77-022, April 1977. The document
presents a critical review of the litera-
ture pertinent to biological, chemical,
and physical reactions, and mechanisms
of attenuation (decrease in the maximum
concentration for some fixed time as
distance traveled) of the selected ele-
ments arsenic, beryllium, cadmium, chromi-
um, copper, iron, mercury, lead, selenium,
and zinc, together with asbestos and
cyanide, in soil systems.
Controlled Lab Studies
The initial effort5 is examining
the factors that attenuate contaminants
(limit contaminant transport) in leachate
from municipal solid waste landfills.
Although the work is strongly oriented
towards problems of disposal of strictly
municipal wastes, the impact of co-
disposal of municipal and hazardous
wastes is also considered. The project
is concerned with contaminants normally
present in leachates from municipal solid
waste landfills and with contaminants that
are introduced or increased in concentra-
tion by co-disposal of hazardous wastes.
These contaminants are: arsenic,
beryllium, cadmium, chromium, copper
cyanide, iron, mercury, lead, nickel,
selenium, vanadium, and zinc. The gen-
eral approach was to pass municipal
leachate through columns of well char-
acterized whole soils maintained in a
saturated anaerobic state. The typical
municipal refuse leachate was spiked with
high concentrations of metal salts to
achieve a nominal concentration of 100
mg/1. The most significant factors in
contaminant removal were then inferred
from correlation of observed migration
rates and known soil and contaminant
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characteristics. This effort will con-
tribute to the development of a computer
simulation model for predicting trace
element attenuation in soils. Modeling
efforts to date have been hindered by the
complexity of soil-leachate chemistry.
Interim results of this effort have been
reported by Fuller, VI. H., et al., 1976,
"Contribution of Soil to Migration of
Certain Common and Trace Elements,"
Soil Sci. 122: 223-235 and by Korte,
N. E., et al., 1976, "Trace Element Move-
ment in Soils: Influence of Soil Chemical
and Physical Properties", Soil Sci. 122:
350-359.
The second effort5 in this area is
studying the removal of contaminants
from landfill leachates by soil clay min-
erals. Columns were packed with mixtures
of quartz sand and nearly pure clay min-
erals. The leaching fluid consisted of
typical municipal refuse leachate with-
out metal salt additives. The general
approach to this effort was similar to
that described in the preceding effort
except that (1) both sterilized and
unsterilized leachates were utilized
to examine the effect of microbial
activity on hydraulic conductivity and
(2) extensive batch studies of the sorp-
tion of metals from leachate by clay
minerals were conducted. Interim results
of this effort have been reported in two
articles by Griffin, R. A., et al.,
"Attenuation of Pollutants in Municipal
Landfill Leachate by Clay Minerals:
Part 1 - Column Leaching and Field Veri-
fication," Environmental Geology Notes,
No. 78, November 1976, Illinois State
Geological Survey, Urbana, Illinois,
and "Attenuation of Pollutants in Munici-
pal Landfill Leachate by Clay Minerals:
Part 2 - Heavy Metal Adsorption Studies,"
Environmental Geology Notes, No. 79, March
1977, Illinois State Geological Survey,
Urbana, Illinois.
The third effort1* relates to modeling
movement in soil of the landfill gases,
carbon dioxide and methane. The modeling
movement has been verified under labora-
tory conditions. This effort has not
focused on the impact of gases on ground-
water, but considers groundwater as a sink
for carbon dioxide. Results to date have
involved design curves and tables which
have been used to successfully evaluate a
gas problem in Minnesota.
A fourth effort5 relates to the use
of large-scale, hydrologic simulation
modeling as one method of predicting
contaminant movement at disposal sites.
The two-dimensional model that was used
successfully to study a chromium con-
tamination problem is being developed
into a three-dimensional model and will
be tested on a well-monitored landfill
where contaminant movement has already
taken place. Although this type of model
presently needs a substantial amount of
input data, it appears promising for de-
termining contaminant transport proper-
ties of field soils and, eventually,
predicting contaminant movement using a
limited amount of data.
Field Verification
Limited field verification is being
conducted. The initial effort to date
has consisted of installing monitoring
wells and coring soil samples adjacent to
three municipal landfill sites to identify
contaminants and determine their distri-
bution in the soil and groundwater beneath
the landfill site. The sites represent
varying geologic conditions, recharge
rates, and age, ranging from a site
closed for 15 years to a site currently
operating. Individual site character-
istics were identified, and sample
analyses necessary to determine the pri-
mary pollutant levels in the waste soils
and groundwater were determined. Valida-
tion of waste Teachability and pollutant
migration potential are to be determined.
Organic Contaminants
The initial effort1 relates to or-
ganic contaminant attenuation by soil.
Much more is known about inorganic con-
taminant movement in soil because the
analytical techniques for inorganic
materials are well developed and rela-
tively cheap compared to the time-
consuming analytial techniques for
organic materials. The problem is
compounded by the fact that organic
contaminants are more numerous and more
are being synthesized all the time. PCB
is the organic contaminant currently being
investigated. In initial results, PCB's
were found to be immobile in earth
materials when measured by the soil
thin-layer chromatography technique.
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POLLUTANT CONTROL
Pollutant control studies are needed
because experience and case studies have
shown that some soils will not protect
groundwater from contaminants. Even sites
with "good soils" may have to be improved
to protect against subsurface pollution.
The overall objective of the pollutant
control studies is to lessen the impact
of pollution from waste disposal sites by
technology that minimizes, contains, or
eliminates pollutant release and leaching
from waste residuals disposed of to the
land.
The pollutant control studies are
determining the ability of in-situ soils
and natural soil processes to attenuate
leachate contaminants as the leachate mi-
grates through the soil from landfill
sites. The studies are also determining
how various synthetic and admixed materi-
als may be utilized as liners to contain
and prevent leachates from migrating from
landfill sites.
Natural Soil Processes
The treatment by natural soil pro-
cesses of pollutants from hazardous waste
and municipal refuse disposal sites is
being performed in Pollutant Transport
studies wherein various soils are being
evaluated in column studies for their
pollutant attenuation capabilities. The
initial effort5 is current investigation
of soils ranging in texture from sands to
clays. In a second effort5 various per-
centages of the clay minerals kaolinite,
montmorillonite, and illite are mixed with
pure sand to form various mixtures that
are packed into columns for study. A
state-of-knowledge report describing
attenuation mechanisms has been published.
See Movement of Selected Metals, Asbestos,
and Cyanide in Soils: Applications to
Waste Disposal Problems. EPA-600/2^77^022,
April 1977.
Li ners/Membranes/Admi xtures
The liner/membrane/admixture technolo-
gy6 is being studied to evaluate suita-
bility for eliminating or reducing leach-
ate from landfill sites of municipal or
industrial hazardous wastes. The test
program will evaluate, in a landfill
environment, the chemical resistance and
durability of the liner materials over
12-, 24-, and 36-month exposure periods to
leachates derived from industrial wastes,
SOx wastes, and municipal solid wastes.
Acidic, basic, and neutral solutions will
be utilized to generate industrial waste
leachates.
The liner materials being investi-
gated under the municipal solid wastes
program include six admixed materials
and six flexible membranes. The admixed
materials are:
- 2 asphalt concretes, varying in
permeability
- 1 soil asphalt
- 2 asphalt membranes, one based on an
emulsified asphalt and the other on
catalytically-blown asphalt
- 1 soil cement
The six flexible membranes are:
- Butyl rubber
- Ethylene propylene rubber (EPDM)
- Chlorinated polyethylene (CPE)
- Chlorosulfonated polyethylene (HYPALON)
- Polyethylene (PE)
- Polyvinyl chloride (PVC)
Specimens of these 12 liner materials
have been exposed for more than 2 years
to landfill leachates generated in in-
dividual simulated landfills. After 1
year of exposure, a set of 12 of the
simulated landfills'was dismantled and
the liners retrieved and tested. The
results of the 1-year exposure have been
discussed in a report entitled Evaluation
of Liner Materials Exposed to Leachate -
Second Interim Report. EPA-600/2-76-255,
September 1976.
POLLUTANT TREATMENT
The pollutant treatment studies re-
late to the collected leachate that is
physically, chemically, or biologically
treated prior too discharge from the land-
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fill site. Also, recirculation and spray
irrigation concepts are considered to be
potential treatment schemes. The overall
objective of the pollutant treatment
studies is to develop technology that
treats the landfill leachate once it has
been collected and contained at the land-
fill site.
Physical-Chemical Treatment
Various physical-chemical treatment
schemes" were investigated in the labora-
tory. Physical-chemical treatments con-
sisted of chemical precipitation, acti-
vated carbon adsorption, and reverse
osmosis. The activated carbon was quite
effective in removing refractory organics
in the effluent of biological units. The
most promising treatment scheme, an anaer-
obic lagoon followed by aerobic polishing,
was selected for pilot plant evaluation.
The results of this initial effort have
been reported by Ho, S., Boyle, W. C., and
Ham, R. K., "Chemical Treatment of
Leachates from Sanitary Landfills,"
JWPCF. Vol. 46, No. 7, July 1, 1974,
pp. 1776-1791.
A second effort" on the physical-
chemical treatment schemes was an expan-
sion of the initial effort not only in
the areas of chemical precipitation,
activated carbon, and reverse osmosis, but
also in ion exchange .adsorption and
chemical oxidation. The results of this
effort have been reported by Chian, S. K.
and DeWalle, F. B., "Sanitary Landfill
Leachates and Their Treatment," JEEP,
ASCE, Vol.102, No. EE2, Proc. Paper 12033,
April 1976, pp. 411-431.
A third effort5 involves a labora-
tory evaluation of various materials that
could be utilized as retardant materials
to minimize migration of pollutants from
disposal sites. This investigation in-
volves study of the following materials
on a pilot plant basis: agricultural
limestone, hydrous oxides of Fe (ferrous
sulfate mine waste), lime-sulfur oxide
(stack-gas waste), certain organic wastes,
and soil sealants. Preliminary research
on limestone and Fe hydrous oxide liners
indicates these materials have a marked
retarding influence on many of the trace
elements. However, the increased water
contamination from solubilization of iron
seems to rule out use of iron oxides in
this treatment scheme.
Biological Treatment
Various unit processes for biologi-
cal treatment of leachate" have been in-
vestigated in the laboratory. The re-
sults of this initial effort have been
reported by Boyle, W. C. and Ham, R. K,
"Treatability of Leachate from Sanitary
Landfills," JWPCF. Vol.46, No. 6,
June 1974, pp. 860-872. A second effort1*
has investigated the process kinetics, the
nature of the organic fraction of leach-
ate, and the degree of treatment that may
be obtainable using conventional waste-
water treatment methods. The biological
methods evaluated were the anaerobic
filter, the aerated lagoon, and combined
treatment of activated sludge and muni-
cipal sewage. Biological units were
operated successfully without prior
removal of the metals that were present
in high concentrations. The results of
this effort have been reported by Chian,
S. K. and DeWalle, F. B., "Sanitary
Landfill Leachates and Their Treatment,"
JEEP, ASCE, Vol.102, No. EE2, Proc. Paper
12033, April 1976k pp. 411-431.
Recirculation
Recycling of leachate" is being in-
vestigated to determine the beneficial
aspects of recirculation as a means of
leachate control and accelerated landfill
stabilization. Recommended design,
operation, and control methods applica-
ble to conventional sanitary landfill.
practice will be developed. This effort
was discussed earlier under the "Waste
Pecomposition" section, and the published
report is mentioned in that section.
Spray Irrigation
Spray irrigation" of leachate is
being investigated as a low-cost, on-
site treatment scheme. Optimum leachate
loading rates and removal efficiencies
for organic and inorganic constituents
are being determined for two soil types.
The technique appears to be sensitive to
moisture stresses (drought).
CO-PISPOSAL
In an effort to assess the impact of
co-disposal, the disosal of industrial
waste materials with municipal solid
waste, a project utilizing large scale
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experimental landfill test cells was
undertaken. Concern has been voiced that
the addition of industrial waste may re-
sult in the occurrence of various toxic
elements in leachates and thereby pose a
threat to potable groundwater supplies.
Because the environmental effects from
landfill ing result from not only the
soluble and slowly soluble materials
placed in the landfill but also the
products of chemical and microbiological
transformations, these transformations
should be a consideration in management
of a landfill to the extent that they can
be predicted or influenced by disposal
operations.
Presently, little is known on what
effect adding industrial waste has on the
decomposition process and the quantity
and quality of gases and leachate produced
during decomposition. There is a strong
concern that addition of industrial wastes,
particularly those high in heavy metals,
will result in elevated metal concentra-
tions in the leachates and potentially,
in potable groundwater supplies. Advocates
of co-disposal of sludges and municipal
waste believe the presence of organics in
the landfill will immobilize heavy metals.
They also believe the presence of such
sludges may accelerate the decomposition
process and shorten the time required
for biological stabilization of the
refuse. Because of the high moisture
content and, commonly, the high pH and
alkalinity of these sludges, periodic
analyses of the leachates in this study
for trace and heavy metals is expected to
provide data to allow rational evaluation
of the practice of co-disposal. The over-
activity is to evaluate and develop a
predictable formulation for the trans-
formation process.
The initial effort1* involves a study
of the factors influencing (1) the rate of
decomposition of solid waste in a sanitary
landfill, (2) the quantity and quality of
gas and leachate produced during decom-
position, and (3) the effect of admixing
industrial sludges and sewage sludge with
municipal refuse. A combination of muni-
cipal solid waste and various solid and
semi-solid industrial -wastes was added
to several field lysimeters. All material
flows were measured and characterized for
the continuing study and related to
leachate quality and quantity, gas pro-
duction, and microbial activity.
The industrial wastes investigated
were: petroleum sludge, battery pro-
duction waste, electroplating waste,
inorganic pigment sludge, chlorine
production brine sludge, and a solvent-
based paint sludge. Also, municipal
digested primary sewage sludge dewatered
to approximately 20 percent solids was
utilized at three different ratios.
The results of this initial effort have
been reported by Streng, D. R., "The
Effects of Industrial Sludges on Landfill
Leachate and Gas," Proceedings - National
Conference on Disposal of Residues "on"
Land, September 1976, pp. 69-76.
A second effort5 to assess the
potential effects of co-disposal involves
the leaching of industrial wastes with
municipal landfill leachate as well as
water. Results to date indicate that,
when compared with water, municipal land-
fill leachate solubilizes greater amounts
of metals from the wastes and promotes
more rapid migration of metals through
soil. The municipal landfill leachate
is a highly odorous material containing
many organic acids and is strongly buf-
fered at a pH of about 5. Consequently,
it has proved to be a very effective
solvent. It is anticipated that during
the life of this effort, studies will be
conducted on 43 industrial wastes, 3
types of coal flyash, and 6 sludges
generated by the removal of sulfur oxides
from the flue gases of coal-burning power
plants. Because of the difficulty in
handling and analyzing municipal landfill
leachate, it will be used with only some
of these wastes.
A third effort6 involves a study of
the effects of co-disposing of chemically
stabilized sludges in a municipal refuse
landfill. This effort has just been ini-
tiated and the simulated landfill lysime-
ters have recently been constructed. It
is anticipated that the loading of these
test lysimeters will be completed by
August 1977.
ENVIRONMENTAL ASSESSMENT
The environmental effects of waste
disposal to the land need to be deter-
mined in relation to the management and
disposal practices for municipal solid
wastes. In an effort to assess the im-
pact of these practices, several studies
have been initiated. The overall
-------
objective is to develop predictive
procedures for forecasting adverse en-
vironmental effects from land disposal
activities and to provide user documents
for implementing field practices for those
methods that eliminate or minimize adverse
effects.
The initial effort7 involves deter-
mining the effects of application of com-
posted municipal wastes and sewage sludge
on selected soils and plants of croplands.
Multiple applications of composted muni-
cipal refuse totaling 900 metric tons per
hectare have resulted in satisfactory
crop growth with only a moderate increase
of some heavy metals in plant tissues.
Very little downward movement of heavy
metals was observed under conditions of
heavy leaching in greenhouse or natural
outdoor conditions. The effort has been
published in a USEPA report entitled
Effect of Land Pisposal Applications
of Municipal Hastes on Crop Fields and
Heavy Metal Uptake, EPA-600/2-77-014,
April 1977.
A second effort6 involves a deter-
mination or evaluation of vegetation kills
and growth problems associated with land-
fill gas migration as evaluated by mail
survey and on-site investigations.
Additional investigations are being per-
formed to determine control measures for
reducing vegetation losses, and experi-
mental plot observations should determine
those vegetation species most conducive
to landfill environs. The results of
this initial effort have been reported by
Flower, F. B., Leone, I. A., and Gilman,
E. F., "An Investigation of the Problems
Associated with Growing Vegetation on or
Adjacent to Refuse Landfills," Proceedings
Physical Environment Conference,
August 1975.
A third effort1 has recently been
initiated to study the operational and
aesthetic effects of milled refuse parti-
cle size in a landfill operated without
daily cover. The overall objective of
this research is to establish acceptable
parameters for the operation and mainte-
nance of milled refuse landfills in order
to minimize detrimental environmental
effects. Specific variables to be evalu-
ated are: the effect of wind velocities
and direction on the movement of land-
filling material; the amount of differen-
tial settlement associated with particle
size variations; the initial density in
each test cell and subsequent density with
relation to time and consolidation within
the cell and the presence or absence of
surface crusting; qualitative evaluation
of nuisance organisms, wildlife, and the
type and amount of plant growth; and some
evaluation of odors and background
conditions potentially responsible for
noticeable odors.
REMEDIAL ACTION
OSW has concluded the investigation
of 391 damage cases. Fifteen percent
of these cases involved groundwater pollu-
tion from hazardous waste landfills, 25
percent involved groundwater pollution
from indiscriminate dumping practices,
and 40 percent involved leachate prob-
lems. Nine percent or 35 of the 391
damage cases involved well pollution.
An ongoing study by OSW has identified 50
incidents of well contamination due to
municipal landfill disposal sites.
Seventy-five to 85 percent of all MSW
sites investigated are contaminating
ground or surface waters. In order to
determine the best practical technology
and economical corrective measures to
remedy these landfill leachate and gas
pollution problems, a research effort has
recently been initiated2 to provide local
municipalities and users with the data
necessary to make sound judgments on
the selection of viable, in-situ,
remedial procedures and to give them an
indication of the cost that would be
associated with such a project. This
research effort consists of three phases.
Phase I will be an engineering feasi-
bility study that will determine on a
site specific basis the best practicable
technology to be applied from existing
neutralization or confinement techniques.
Phase II will determine the effectiveness,
by actual field verification, of the
recommendations/first phase study.
Phase III will provide a site remedial
guide to local municipalities and users.
LANDFILL ALTERNATIVES/LAND CULTIVATION
Municipal solid wastes are primarily
deposited in standard sanitary landfills
or incinerated. Because of concern for
environmental impact and economics, other
landfill alternatives have been proposed.
10
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For SHWRD purposes, the alternatives
currently being considered are: (1) deep
well injection, (2) underground mines,
(3) land cultivation, and (4) saline
environments. The deep well injection
and underground mine alternatives are
strictly orientated towards hazardous
wastes and as such will not be discussed
in this symposium or its proceedings.
The remaining two alternatives are,
however, orientated towards municipal
waste. In order to assess the feasibility
and beneficial aspects of spreading
and admixing municipal refuse into the
soil, an initial effort6 involves land
cultivation and the preparation of a
state-of-the-art document. Available
data indicate that application of shredded
municipal refuse or compost to marginal or
drastically disturbed land improves soil
structure and fertility, thus making re-
vegetation possible. It appears that the
environmental pollution caused by land
cultivation is minimal as compared to
that for landfills, primarily due to
maintenance of aerobic conditions and the
lower concentration of waste per unit
area of land. Technical and economic
assessment efforts will follow.
A second effort1 recently begun in-
volves documenting the disposal of muni-
cipal solid wastes in saline environments,
i.e., estuaries and coastal marshlands.
The purpose of this study is to obtain a
document detailing the present environ-
mental and economic status of municipal
solid waste disposal into specific saline
environments and compiling state regula-
tions and policies in effect for those
states bordering saline waters.
ECONOMIC INCENTIVES
The use of market-related incentive
(disincentive) mechanisms has received
only scant consideration for pollution
control policy in the United States, par-
ticularly.in the area of solid waste man-
agement. It has been hypothesized that
incrementally pricing solid waste collec-
tions and disposal would reduce the waste
generation rate, enhance source separation
of recyclable materials, accelerate tech-
nological innovation, and minimize total
system cost. It has also been asserted
that properly structured prices or user
charges would be an equitable means of
allocating public resources and an effi-
cient system for maximizing net Asocial
benefits of a municipally provided
service. In order to evaluate these
statements, award of the initial effort8
to delineate the conditions under which
user charges would be economically
feasible for solid waste management is
anticipated in FY 19,77.
CONCLUSION
The laboratory and field research
project efforts discussed here reflect
the overall SHWRD effort in municipal
solid waste disposal research. The
projects will be discussed in detail
in the following papers. More infor-
mation about a specific project or study
can be obtained by contacting the project
officer referenced in the text. Inquiries
can also be directed to the Director,
Solid and Hazardous Waste Research
Division, Municipal Environmental Research
Laboratory, U.S. Environmental Protection
Agency, 26 West St. Clair Street,
Cincinnati, Ohio 45268. Information
will be provided with the understanding
that it is from research in progress and
that conclusions may change as techniques
are improved and more complete data
become available.
PROJECT OFFICERS
1. Mr. Richard A. Carnes, Municipal En-
vironmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St. Clair Street, Cincinnati,
Ohio 45268. 513/684-7871.
2. Mr. Donald E. Sanning, Municipal En-
vironmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St. Clair Street, Cincinnati,
Ohio 45268. 513/684-7871.
3. Mr. Michael Gruenfeld, Industrial En-
vironmental Research Laboratory, U.S.
Environmental Protection Agency,
Edison, New Jersey 08817.
201/321-6625.
4. Mr. Dirk R. Brunner, Municipal Envi-
ronmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St. Clair Street, Cincinnati,
Ohio 45268. 513/684-7871.
11
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5. Dr. Mike H, Rouller, Municipal Envi-
ronmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St. Clair Street, Cincinnati,
Ohio 45268. 513/684-7871.
6. Mr. Robert E. Landreth, Municipal En-
vironmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St. Clair Street, Cincinnati,
Ohio 45268. 513/684-7871.
7. Mr. CaHton C. Wiles, Municipal Envi-
ronmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St. Clair Street, Cincinnati,
Ohio 45268. 513/684-7881.
8. Mr. Oscar W. Albrecht, Municipal Envi-
ronmental Research Laboratory, U.S.
Environmental Protection Agency,
26 West St, Clair Street, Cincinnati,
Ohio 45268. 513/684-7881.
12
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SUMMARY OP OFFICE OF SOLID WASTE GAS AND LEACHATE ACTIVITIES
Truett V. DeGeare, Jr.
Office of Solid Waste
U.S. Environmental Protection Agency
Washington, D. C. 20460
Two years ago this month I had the
pleasure of participating in the first
of this series of symposia being spon-
sored by our sister office, the Solid
and Hazardous Waste Research Division.
At that time I discussed several field
projects, in the areas of landfill gas
and leachate, in which we were involved
or hoped to become involved. I also
indicated the likelihood that in the
future we would see a need for expansion
of land disposal criteria or guidelines
at the Federal and/or State levels.
Today, I intend to again discuss some
of our field projects, a few of which
you may recognize as being only desires
two years ago. I also, again, intend
to briefly discuss the need for expan-
sion of disposal criteria or guidelines,
an area of anticipation only two years
ago which today is reality due to
enactment of the Resource Conservation
and Recovery Act of 1976.
Field Projects
Leachate Control
In the area of leachate control
we are currently involved in five
significant efforts; four of which
relate to leachate treatment, while
the fifth is concerned with containment.
At Enfield, Connecticut, an
anaerobic filter system has been con-
structed for the treatment of leachate.
The design was based on bench-scale
research conducted by the University of
Illinois. The project was instituted
in June 1975 with bench-scale studies
and has proceeded through design and
construction of the facility. Construc-
tion is complete; however, system start-
up has been delayed pending mechanical
repair found necessary during testing.
The bench-scale testing has indicated
that we may expect COD removals of up
to 90%. Evaluation of the field
facility will be conducted through
April 1978.
In Falls Township, Pennsylvania,
Waste Resources Corporation has con-
structed a physical/chemical/ biological
treatment facility to treat leachate
generated by its lined landfill.
Although we were not involved in the
construction of this facility, we have
been funding an evaluation of the
plant's operation with regard to cost
and performance. The evaluation is
being conducted by Applied Technology
Associates. This plant was of special
interest to us for evaluation in that
its design provided, for variation in
mode of operation. Thus, at one facility
and with a single source of leachate,
we were able to evaluate four systems.
1. chemical/physical treatment
followed by biological
(activated sludge),
2. chemical/physical treatment
only,
13
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3. biological treatment followed
by chemical/physical,
and
4. biological treatment only.
In addition, carbon absorption polishing
of each of the above system effluents
could be examined on a bench-scale
basis. To date, systems 1 and 2 have
been evaluated with encouraging results.
Systems 3 and 4 have received only
preliminary attention; however, it
appears that the raw leachate inhibits
the activated sludge process to the
extent that pretreatment is required.
These latter two systems will be
evaluated further this spring. Thus
far, the plant has performed most
satisfactorily in the mode of system 1
which, for example, reduced BOD by 99%,
COD by 94%, cadmium by 71%, iron by
99%, and lead by 78%. Costs for this
mode are in the range of $4 to $5 per
thousand gallons treated. Further
details on this project should be
available this summer in an interim
report which is currently being prepared.
Through an interagency agreement
we are contributing to the USDA
Agricultural Research Service's
evaluation of the performance of a
leachate treatment system. This system,
located near Bluefield, West Virginia,
employs an aerated lagoon and spray
irrigation. Leachate from the lagoon
is being sprayed on plots of vegetated
land from which soil, soil moisture,
and vegetation samples are obtained
and analyzed. The study is intended
to determine:
1. The efficiency of spray
irrigation as a decontamina-
tion method,
2. The effects of lime treatment
of soil on the soil's
ability to complex and retain
leachate contaminants,
3. The effectiveness of the
aerated lagoon, and
4. The effects of spray irrigation
on the vegetation.
Results of this study are not yet
available; however, an interim report
is under preparation.
We have just recently contracted
for the field evaluation of up to six
existing leachate treatment systems.
The recent Waste Age Survey of U.S.
Disposal Practices (as reported in
Waste Age, January 1977) indicated the
existence of some 200 such facilities.
Our intent here is to provide case
study information on the design,
cost, and performance of specific
systems presently in use. Hopefully,
this information will be of value to
engineers and disposal facility
operators who are considering the design
and operation of leachate treatment
facilities. The facilities to be
evaluated have not yet been identified.
Should you wish to suggest particular
facilities for evaluation, I would like
to hear from you by the end of the
month.
As I mentioned in 1975, we are using
funds provided by the Appalachian
Regional Commission to support the
construction of a lined sanitary land-
fill in Lycoming County, Pennsylvania.
The project has moved through design
to solicitation of construction bids.
We are hoping that the facility will
begin operation this fall. This pro-
ject will provide full documentation of
the design, construction techniques,
and costs of a lined sanitary landfill.
For additional information on the
design of this facility, I suggest you
review a recent paper on the Lycoming
County project which was prepared by
Todd Giddings and published in the
January-February 1977 edition of
Ground Water.
Leachate Monitoring
We are continuing several of the
leachate monitoring efforts which were
funded in earlier years. These con-
tinuations are significant in that,
although leachate generation and
movement are recognized to be time-
dependent, long-term data are rare.
14
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In 1970 we initiated a project to
demonstrate a unique approach to
sanitary landfill operation in a high
water table area, namely, Orange County,
Florida. Part of the demonstration
involved the installation and monitoring
of a series of ground water wells. The
Orange County Pollution Control Board
has continued to monitor this facility
for seven years, an effort scheduled
to terminate this fall. The data has
indicated that subsurface leachate
movement has been confined to the area
directly beneath the completed cells;
vertical movement has been detected to
a depth of 27 feet. The surface drainage
system, designed to prevent flooding and
to lower the water table, has exhibited
increased oxygen demand only in the
detention pond and part of the outfall
canal.
This summer will bring to an end
Professor Robert Ham"s seven-year
monitoring effort at the University of
Wisconsin. Dr. Ham will be producing
a final report on a series of 400-cu-yd
lysimeters constructed to simulate the
land disposal of milled and unprocessed
solid waste under various conditions.
During 1973 and 1974 we participated
in the evaluation of a baler operation
in St. Paul, Minnesota. The evaluation
included the construction and monitoring
of a test cell of baled solid waste;
however, only short-term monitoring was
provided through that project. A report
on that project, conducted by Ralph
Stone and Company, is available from
our office. Last summer we were able
to fund an effort by the Oniverisity
of Minnesota to repair the monitoring
system, which had been unattended for
two years, and reinstitute a monitoring
program. Due to physical problems at
the site, including a severe winter,
little data has been obtained thus
far. The project is scheduled to ter-
minate in-1978.
In speaking of monitoring, I wish
to mention a recent c'ontract effort
which produced a document which I think
would be of value to many of you. In
our discussion with researchers, con-
sultants, site operators, and repre-
sentatives of State and local government
it had become obvious that guidance
was needed and desired in the area
of leachate monitoring, especially
with regard to subsurface movement. In
response to this need we contracted
with Wehran Engineering Corporation
and Geraghty and Miller, Inc. to produce
a "Procedures Manual for Monitoring
Solid Waste Disposal Sites." The manual
was produced with valuable input from
representatives of State agencies, the
consulting engineering sector, U.S.
Geological Survey, the disposal facility
operators sector, and the water-well
industry. The manual is very comprehen-
sive, providing information on the
objectives and costs of monitoring,
specific monitoring techniques such as
electrical earth resistivity and various
types of well systems, sampling, and
analytical techniques. The manual
has been well received, and we have
just recently asked for a second printing.
Gas
We are dealing with landfill gas
in two areas: recovery and control.
Our gas recovery project is being
conducted by the City of Mountain View,
California, and Pacific Gas and Electric
Company. The project is progressing,
although slowly, into the production
stage. The gas treatment unit has been
constructed and the compressor has been
ordered for June delivery. This spring
the 18 production wells will be con-
structed. The compressor and molecular
sieve treatment unit will then be
installed and gas will be extracted,
upgraded to 750 BTU/scf, and injected
into an adjacent commercial gas pipeline.
The system is to extract 1 million scf
per day and produce about 500,000 scf
per day of high quality gas. Reports by
the City on gas extraction and by the
utility on gas utilization should be
available from us this summer.
Severe gas migration problems con-
tinue to come to our attention. However,
there are few sources of information
on control techniques. In order to
provide guidance on control systems
which have been used in the field
either successfully or unsuccessfully,
we have recently obtained a report
15
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from Engineering Science/ Inc. on the
design, construction, operation, and
costs of five such control systems.
In that we received the report only
last week and have not had an opportunity
to review it, I can't reflect further
on its contents. We hope to have the
report available for distribution this
summer.
Criteria and Guidelines
As you are probably now all aware,
last October the Resource Conservation
and Recovery Act of 1976 (RCRA) became
law. With regard to solid waste
disposal, RCRA includes some significant
definitions and requirements which I
would like to discuss.
Three of the requirements placed
on EPA are that we:
1. promulgate regulations con-
taining criteria for deter-
mining which disposal
facilities shall be classi-
fied as sanitary landfills or
as open dumps;
2. publish an inventory of all
disposal facilities in the
country which are open dumps;
and
3. promulgate suggested guidelines,
including a description of
levels of performance to pro-
tect ground waters from leachate.
RCRA recognizes "open dumps" and
"sanitary landfills" as the only types
of solid waste disposal facilities and
defines them by reference to classifi-
cation criteria which are to be promul-
gated under §4004. RCRA also specifi-
cally defines the terms "disposal" and
"solid waste" with considerable breadth:
The term "disposal" means the
discharge, deposit, injection, dumping,
spilling, leaking, or placing of any
solid waste or hazardous waste into or
on any land or water so that such solid
waste or hazardous waste or any
constituent thereof may enter the
environment or be emitted into the air
or discharged into any waters, including
ground waters.
The term "solid waste" means any
garbage, refuse, sludge from a waste
treatment plant, water supply treatment
plant, or air pollution control facility
and other discarded material, including
solid, liquid, semisolid, or contained
gaseous material resulting from indus-
trial, commercial, mining, and agricul-
tural operations, and from community
activities, but does not include solid
or dissolved material in domestic
sewage, or solid or dissolved materials
in irrigation return flows or industrial
discharges which are point sources sub-
ject to permits under Section 402 of the
Federal Water Pollution Control Act, as
amended or source, special nuclear, or
by-product material as defined by the
Atomic Energy Act of 1954, as amended.
As I said earlier, RCRA defines the
terms "open dump" and "sanitary landfill"
by reference to specific criteria to be
developed pursuant to 84004. This
section requires that we promulgate
regulations containing criteria for
determining which facilities shall be
classified as sanitary landfills and
which shall be classified as open dumps.
At a minimum, the criteria are to
provide that a facility may be classi-
fied as a sanitary landfill and not an
open dump only if there is no reasonable
probability of adverse effects on health
or the environment from disposal of solid
waste at the facility. An important
aspect of the implementation of RCRA,
then, is delineation of what constitutes
"no reasonable probability" and what
constitutes "adverse effects on health or
the environment." The law requires that
these regulations be promulgated by
October 21, 1977, after consultation with
the States and after notice and public
hearings.
Not later than one year after
promulgation of the criteria for
classification of disposal facilities,
we must publish an inventory of all
disposal facilities in the United States
which are open dumps.
The legislative intent appears to
be not for Federal regulation of disposal,
but for State control. The law requires
that each State plan prohibit the
establishment of open dumps and contain
a requirement that all solid waste
16
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within the State be disposed of in
sanitary landfills unless it is utilized
for resource recovery. The State
prohibition is to be effective six
months after promulgation of the
criteria or on the date of approval of
the State plan, whichever is later.
In addition to the State prohibi-
tion, the law contains a Federal
prohibition of open dumping when usable
alternatives are available. Where
entities can demonstrate that they are
unable to utilize such alternatives, the
State plan must establish a timetable
or schedule for compliance. The com-
pliance schedule must specify remedial
measures, including an enforceable
sequence of actions, leading to com-
pliance with the prohibition within a
reasonable time not to exceed five
years from the date of publication of
the inventory. If a State plan is not
being pursued, the citizen suit pro-
vision of the law provides recourse to
aggrieved parties.
As did the 1965 Act, RCRA
requires that we publish suggested
solid waste management guidelines which
are mandatory only for Federal agencies
and certain recipients of Federal
financial assistance. The guidelines
are to provide technical and economic
descriptions of levels of performance
of solid waste management practices.
Areas to be addressed by the guidelines
include appropriate methods and degrees
of control that provide for protection
of public health and welfare; protection
of the quality of ground waters and sur-
face waters from leachates; protection
of the quality of surface waters from
runoff through compliance with effluent
limitations under the Federal Water
Pollution Control Act, as amended;.pro-
tection of ambient air quality through
compliance with new source performance
standards or requirements of air quality
implementation plans under the Clean
Air Act, as amended; disease and vector
control; safety; and esthetics. As in
the 1965 Act and its amendments, RCRA
does not specify which solid waste
management practices are to be
addressed by the guidelines. To us
it seems most appropriate to first.
direct our guidelines efforts to the
land disposal of solid wastes and
the disposal and utilization of municipal
waste water treatment sludges. In
determining other practices to address,
we solicit your viewpoints.
In the near future, probably
next month, you can expect to see in
the Federal Register Advance Notices
of Proposed Rulemakings (ANPRs)
addressing the criteria and guidelines.
These notices will not be draft or
proposed criteria and guidelines. They
will be an explanation of the require-
ments of the law along with questions
or issues of concern in developing the
criteria and guidelines to meet the
requirements. The notices are our way
of formally notifying the public of
our intentions and soliciting their
response to the questions and issues.
I hope that you will feel free to
respond as described in the notices and
provide any information or suggestions
you may have to contribute.
At this time, so that you might
be able to identify them later, I would
like to introduce three other repre-
sentatives of our Agency. Dr. John
Skinner is directing the activities of
our Systems Management Division which
is responsible for the criteria and
guidelines I have mentioned. Mr. Sheldon
Meyers directs the activities of the
Office of Solid Waste and will address
you at the banquet tonight. Mr. Morris
Tucker, is responsible for our solid
waste program in our Region VII with
headquarters in Kansas City. I hope
that during the course of this sympo-
sium you will not hesitate to contact
any of us and express your views regard-
ing our activities and the various
provisions of this new law. Thank you
for your attention.
17
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STATE OF MISSOURI SOLID WASTE MANAGEMENT ACTIVITIES
Robert M. Robinson, P. E., Director
Solid Waste Management Program
Division of Environmental Quality
Missouri Department of Natural Resources
The Solid Waste Management Program
activities in Missouri are directed pri-
marily toward controlling the disposal of
wastes on land. Wastes which we do not re-
gulate include mining and farming residues
and liquid wastes. I will discuss the pro-
gram activities in three areas: land dis-
posal , hazardous waste and planning. This
breakdown of activities corresponds to the
organization of our central office program.
The Solid Waste Management Program is
one of eight environmental programs located
in the Department of Natural Resources'
Division of Environmental Quality. The
Department of Natural Resources was estab-
lished by reorganization of state govern-
ment in 1974. This organization of envir-
onmental programs allows for close coordi-
nation of regulation and surveillance of
environmental facilities within our state.
A total solid waste staff of ten is
located in our Jefferson City office.
Field investigations and technical assis-
tance are provided by regional office pro-
gram staff located in six regional offices
throughout the state. Approximately four
man-years of work are provided annually on
solid waste activities by the regional
office program staff. With a total of 14
man-years of effort it is readily apparent
that the state has a modest commitment of
staff to solid waste activities. However,
I must add that the same relationship of
commitment of staff and resources is also
true for other environmental programs in
Missouri.
Land Disposal
The program's activities to control
disposal of solid waste is based on the
legislative authority provided in 1972.
The Missouri Legislature enacted a law
(Sections 260.200 to 260.245, RSMo., 1975
Supplement) requiring a permit to operate
solid waste disposal areas and processing
facilities. A date of June 30, 1973, was
set by law for obtaining a permit. It was,
of course, not possible in one year to
adopt regulations for disposal areas and
processing facilities, close approximately
480 open dumps and permit an adequate num-
ber of disposal areas. The program estab-
lished a policy of requiring the closure
of open dumps as permitted sanitary land-
fills became available. Our efforts were
directed toward the more highly populated
areas first. At the present time less than
100 open dumps are known to exist in the
state. We have written commitments for
closure of many of these dumps as several
permitted sanitary landfills begin opera-
tion this coming spring.
Since 1973 the state has issued one
hundred and forty-seven (147) operating
permits for sanitary landfills, demolition
landfills, transfer stations, processing
facilities and special disposal sites.
Permits are issued for the life of the area
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or facility. Approximately 822 of the
state's population is presently served by
permitted sites.
The permitting process includes preli-
minary site evaluation by our department.
This site investigation is conducted as a
voluntary service to provide the applicant
some assurance that the disposal area will
be considered suitable before funds are
invested to develop engineering plans.
Site investigations are made by a geologist
with the department's Division of Geology
and Land Survey and an engineer from our
Regional Office Program. From their re-
ports we advise the applicant whether or
not the geology and other physical charac-
teristics of the landfill site look suit-
able. The applicant then makes the deci-
sion whether to employ a consulting engi-
neer to submit detailed engineering design
plans and the application. The Solid Waste
Management Program reviews the application
and plans within approximately 45 days of
receipt. The permit is either issued, de-
nied or revision of plans requested.
The solid waste enforcement activities
have been rather limited to date for the
following reasons: our policy of not clos-
ing dumps until permitted facilities are
available, most disposal area operators
have complied with the law and regulations
by department request or orders, and the
legal assistance available from the
Attorney General's office is in short
supply due to budget constraints. At our
request five legal actions have been filed
by the Attorney General to obtain closure
of an open dump or compliance with operat-
ing regulations for sanitary landfills.
None of the cases have resulted in a court
trial because satisfactory agreements and
compliance were reached.
Routine inspection of permitted dis-
posal areas and processing facilities and
agreements for voluntary closure of open
dumps are accomplished by the staff in the
six regional offices. Permitted disposal
areas and processing facilities are in-
spected an average of twice per year. If
the regional office is unable to obtain a
reasonable commitment for'closure of an
open dump or the operator of a landfill
fails to improve the operation after noti-
fication, the Solid Waste Management Pro-
gram is requested to take legal action.
We have several alternative actions to take
which include: issuance of a department
administrative order, holding of an infor-
mal show-cause hearing, issuance of a re-
vocation of permit and request for legal
action by the Attorney General's office.
The situation determines which type of
action is taken.
Several of the department's legal
actions have involved the discharge of
leachate from non-permitted landfills.
However, we have experienced very few pro-
blems with leachate generation at permitted
sanitary landfills. The problems that have
occurred can be attributed to poor opera-
tion, such as failure to provide daily
cover and proper control of surface drain-
age. Several factors may have helped to
control leachate problems in recent years.
The State of Missouri has experienced below
normal rainfall the past three years, where-
as normally the rainfall is approximately
equal to evaporation. The sanitary land-
fill regulations prohibit the acceptance of
waste containing free moisture. Leachate
collection and treatment is required as
part of the landfill design where site con-
ditions indicate leachate discharges are
likely to occur. Monitoring wells are
being required where leachate could possi-
bly discharge from the site without being
detected on the ground surface.
Gas generation has not proven to be a
problem with permitted sanitary landfills
in Missouri. Gases are generally vented
through the cover material without special
design. We only require special provisions
for gas venting when the landfill is locat-
ed relatively close to buildings.
Hazardous Waste
A statewide hazardous waste survey has
been a major activity of-the Solid Waste
Management Program during the past two
years. We were assisted in conducting the
survey by the Mid-America Regional Council
in the Kansas City area. Four hundred
eighty-one industrial plants were surveyed.
Projection of the survey data indicates
that industry in Missouri is generating
potentially hazardous waste at the rate of
about one million metric tons per year.
The survey report and state plan for haz-
ardous waste management will be completed
and published this year.
Legislation to regulate hazardous
19
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waste has been introduced in the Missouri
Legislature. The legislation was developed
with the assistance of a large volunteer
committee representing industry, public
interest groups, environmentalists, agri-
culture and state and local governments.
With this broad support for the legislation
we believe there is a good chance it will
pass this legislative session.
Our program was instrumental in the
development of the St. Louis Industrial
Waste Exchange operated by the St. Louis
Regional Commerce and Growth Association.
This was the first waste exchange to be
established in the U. S. We do not partic-
ipate in the operation of the St. Louis
exchange, but encourage industries to list
their waste with it. Information is also
provided industry on the availability of
waste recyclers, processing facilities and
hazardous waste disposal areas. Three
special disposal sites have been permitted
in the state to accept hazardous wastes.
Wastes are accepted at these sites only
after information on the properties of the
hazardous waste and handling procedures are
submitted to the Solid Waste Management
Program and we authorize acceptance. Un-
fortunately, these three sites are all
located on the western side of the state.
We hope to have a special disposal site
permitted in the St. Louis area within a
few months.
The waste market for these special
disposal sites is created because the state
solid waste regulations for sanitary land-
fills prohibit the acceptance of hazardous
wastes, bulk liquids, semi-solids, sludges
containing free moisture, highly flammable
or volatile substances, unexpended pesti-
cide containers, pesticides, raw animal
manure, septic tank pumpings, raw sewage
sludge and industrial process sludges un-
less appropriate design criteria and opera-
ting procedures are specifically delineated
in the approved engineering design plans.
Only a few sanitary landfills other than
the special disposal sites have received
approval to accept some of the above listed
wastes. We will not approve the operating
practice of mixing liquid wastes, pesti-
cides or heavy metal sludges with municipal
waste in the sanitary landfill because of
the increased potential for generating
leachate and increasing the difficulty of
treatment.
Planning
The third major program activity is
planning. The solid waste law passed in
1972 and revised in 1975 requires cities
over 500 population and certain counties to
submit a solid waste management plan to the
department for approval. Our program pro-
vides technical assistance to the cities,
counties and regional planning agencies in
development, review and approval of their
solid waste management plans. Most of the
state's twenty regional planning commis-
sions have participated in the planning pro-
cess, resulting in area-wide disposal solu-
tions in many cases. More than 50% of the
state's 114 counties are served by one
landfill or transfer station. Several land
fills are serving two or more counties.
More than 200 cities have implemented
collection services that serve all house-
holds, creating efficient collection
systems and controlling the problems of
promiscuous dumping. Our resource recovery
planning efforts have been limited to a
study of the markets available for re-
covered material in the state.
Our planned activities for the future
include: updating the 1972 State Solid
Waste Management Plan; accepting responsi-
bility for hazardous waste control under
the Resource Conservation and Recovery Act,
if we are successful in obtaining passage
of the Missouri Hazardous Waste Management
Act being considered by the legislature;
establishment of a solid waste training
program; closure of the remaining non-
permitted disposal areas in the state this
year; and encourage through the planning
process area-wide resource recovery
systems in the metropolitan areas of the
state.
Summary
In summary, the State of Missouri has
implemented a comprehensive program to con-
trol the disposal of solid waste on land.
Although leachate and gas generation has
not been a major problem at permitted land-
fills, the program gives special attention
to these potential problems in the review
of engineering design plans.
The management of hazardous waste has
been addressed by conducting a statewide
survey and introducing hazardous waste
legislation. Hazardous waste disposal is
20
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presently controlled by prohibiting their
disposal at sanitary landfills unless spe-
cial design and handling procedures are
approved.
The Solid Waste Management Program
provides technical assistance to local
governments in the development, review and
approval of solid waste management plans.
In the future we plan to increase the
role of the program from primarily a land-
disposal control agency to include resource
recovery planning, solid waste training
and comprehensive regulation of hazardous
wastes.
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REGION VII SOLID WASTE ACTIVITIES
Morris G. Tucker
Chief, Waste Management Section
Air & Hazardous Materials Division
U.S. Environmental Protection Agency
1735 Baltimore Avenue
Kansas City, Missouri 64108
ABSTRACT
The states included within E.P.A., Region VII, are Iowa, Kansas, Missouri, and
Nebraska. These four states have all expended a great amount of effort in developing
and implementing solid waste management programs. From a minuscule total staffing of
two man-years of effort available for this activity in 1968, the four states utilized
43 man-years in 1976. Most of the early effort included survey of municipal solid waste
systems and disposal practices, development of state plans, obtaining needed legislation,
development of rules and regulations, and establishing monitoring and enforcement
activities. Probably the most outstanding example of the success of these efforts is in
improved land disposal of municipal solid waste. In 1970, the region's population of
11,231,000 was served by about 2,400 open dumps and 27 sanitary landfills. On January 1,
1977, this populace was served by about 600 open dumps and 484 sanitary landfills. The
percentage of population served by acceptable land disposal facilities increased from
10 percent in 1970 to 86 percent at the start of 1977.
I would like to start off by expanding
upon the welcome to EPA, Region VII. It
has already been extended to some degree,
even though those of you that came from the
East only made it within the Region by a
couple hundred yards. You probably know
that the Mississippi River is our boundary
line with our Region V.
You are going to be spending about two
and a half days at this meeting on research
and development activities within EPA and
by their contractors. Within this subject
area you will be concentrating on gas and
leachate from landfills receiving municipal
solid waste. One note I would like to make
here is that I notice on the program there
was no distinction made as to whether we
were talking about dumps or whether we were
talking about sanitary landfills. However,
our new legislation, the Resource Conserva-
tion and Recovery Act, calls for there to
be developed a very clear distinction
between the two and that dumps, as so
defined, be closed within a certain
timeframe. It also calls for a redefini-
tion of sanitary landfill before this can
be accomplished. Others have touched on
this during the program and I am sure that
it will be discussed more later, so I will
not elaborate on that in more depth at this
time.
I would like to digress from research
and development views for a few minutes and
concentrate on what I generally call imple-
mentation. Implementation is really the
primary activity that those of us at the
EPA regional level and at the state and
local levels are involved in solid waste
management. Hopefully, we utilize informa-
tion gained by means of the various re-
search and development studies. Still, the
fact remains, there are tremendous
quantities of waste to be disposed of daily
whether or not you have available to you
totally environmentally acceptable facil-
ities.
You are all familiar with reports that
22
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have been published nationally on the
amounts and types of waste generated. Some
of these figures include approximately 135
million tons per year of municipal waste,
an additional 260 million tons per year of
non-hazardous industrial waste, excluding
mining, and over 7 million tons per year of
sewage sludges. Then we get into the big
numbers - approximately 700 million tons
per year of agricultural waste and approx-
imately 1.8 billion tons per year of waste
from the mining industry. Something that
has not been reported on so much, but you
will see a great deal of in the near future,
is the breakdown of the amounts of
hazardous waste or potentially hazardous
waste. Figures that we have prepared to
date, from eight industry groups only,
show that this figure is in the range of
about 23 million tons per year.
What do these figures mean to us at
the regional level? It is only fair to
assume that our states, the four states
within Region VII, generate their fair
share. These states which include Iowa,
Kansas, Missouri and Nebraska have a
population of about 12 million people and,
therefore, generate about 8 million tons
per year of municipal-type waste. This
may not sound like a lot of waste to some
of you from the larger cities back in the
East, but there are also problems asso-
ciated with sparse populations and the
difficulties of combining and establishing
regional systems. Regional figures for our
portion of the other types of waste are not
as well known. However, as Mr. Robinson
just indicated, Missouri, as have the
remainder of our states, has just completed
or is nearing completion of supplementary
studies on industrial wastes. Hopefully,
reports from all four of our states will be
available this Spring.
Since one of the primary roles of
EPA's regional offices is to translate the
perceived national goals in approved waste
management to the states, let's take a
brief look at this activity. This
essentially started with the passage in
1965 of the Solid Waste Disposal Act. This
Act partially funded planning and training
grants to assist our states and, in some
cases, local and regional agencies to look
at this somewhat new subject of improved
solid waste management. At this time, and
until about 1968, the four states within
this region had a total of two man-years of
effort devoted to solid waste management.
In 1968, Missouri and Kansas accepted
grants from EPA's predecessor agency to
study the situation within their respective
states and develop state plans. These
states were followed in 1971 by Iowa and in
1972 by Nebraska. By this time, about
1972, the staffing for the four states had
increased to 21 positions. Many of you are
familiar with the activities conducted
under these grant programs that involved
essentially surveys of municipal systems
and land disposal practices. Additionally,
there was a great amount of training and
technical assistance offered both by those
of us in the regional office and by state
personnel. State plans have been completed
for all four of our states and generally
effective legislation has been obtained to
deal with municipal solid waste. All four
states have been spending the bulk of their
time since plan completion on implementation
activities. This includes continued train-
ing together with increased efforts in
monitoring and enforcement activities.
Currently, the staffing for the four states
in this region totals 43 positions for
these programs. Additionally, over the
past few years we have assisted in the
development of about 15 regional plans
through grants to local and regional
agencies.
Probably one of the best measures of
the effectiveness of this overall activity
is in improved land disposal of municipal
waste. Some summary figures on this shows
that for 1970 the four states in the
region, with a population base of about
11.2 million, had 2,400 open dumps, 27
approved sanitary landfills, and that
10 percent of the population were served
by approved facilities. However, we think
we have done some good since as of the
first of this year, comparible figures show
that we still have about 600 open dumps,
most of them small, but we have increased
the state-approved landfills to 484 and
currently 86 percent of our populace is
served by these approved facilities.
Robbie touched on the hazardous waste
survey that has recently been done in the
State of Missouri. Additionally, this has
been done in the State of Kansas, which
included about 450 firms, the State of
Nebraska surveyed about 90 firms. I do not
have any firm numbers on the State of Iowa
but they have a comparable activity
underway. As follow-up to these studies,
all four of our states currently have
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legislative proposals before their legisla-
tors in an attempt to close the gaps in
existing municipal solid waste legislation
and to obtain needed additional legislation
specifically for hazardous waste management.
I would like to touch just briefly on
some of the research and development
activities that have taken place within
this region. Back in the early days of our
program we had a demonstration project in
Sarpy County, Nebraska, for sanitary
landfill to reclaim a ravine. This project,
although it doesn't sound so glamorous
today, was highly successful and the
reclaimed land now supports a bumper crop
of corn each year. We subsequently had a
large scale demonstration project with the
Mid-Americal Regional Council (MARC) to
establish a demonstration sanitary landfill
project in Kansas City, Kansas. This
project was unique in many aspects, possibly
one of the greatest factors being that it
was located immediately in an urban area..
The landfill was bordered on two sides by
residential housing within about 50 yards
of the operation. Needless to say, there
was substantial opposition when this was
first started. However, appropriate
orientation of local citizen leaders and
neighbors convinced them that it would be
to their benefit to wipe out a very
ugly-looking ravine that had1 been used to
dump trash and, in just a short time, end
up with a community park. This project was
completed about two years ago and that park
development is now taking place. MARC has
maintained continual monitoring since
initiation of the project on leachate.
They have a fully designed leachate under-
drain monitoring system and also a series
of gas wells that are monitored weekly.
The new Resource Conservation and
Recovery Act of 1976 reemphasizes the
position that the state should be the
primary force in the control of health and
environmental problems resulting from
improper solid waste management practices
and as the institutional catalyst for
increasing the conservation and recovery
of resources. Toward this end, EPA will
provide increased technical and financial
support so as to maximize state assumption
of responsibilities under the act. The
primary state tasks described in the Act
include development and implementation of
upgraded solid waste management plans,
the establishment of hazardous waste
management regulatory programs and the
longer term goal of the elimination of all
open dumps. The EPA regional offices will
manage the state grant programs and tech-
nical assistance delivery systems.
Additionally, should any of the states be
unable to upgrade its own dump inventory
survey system, the regional offices will be
called upon to handle this activity. This
also applies to a very substantial part of
the new act on hazardous waste management,
in that if the states are unable to
operate a comprehensive program for
hazardous waste management, this activity
is to be handled by the EPA regional
offices, including the operation of a
permit program.
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LANDFILL RESEARCH ACTIVITIES IN CANADA
H. Mooij, P. Eng.
Waste Management Branch
Environmental Impact Control Directorate
Environmental Protection Service
Fisheries and Environment Canada
Ottawa, Ontario
K1A 1C8
ABSTRACT
In Canada, municipal and industrial solid waste management, including land
disposal, is generally a private sector or local government responsibility carried
out under enabling Provincial Government legislation and regulation. The Federal
government's role is principally to develop solid waste management technology, to
generate and evaluate technical solid waste management information, and to develop
new or improved guidelines or codes of good practice relating to various waste
management aspects. These activities are conducted on a national basis as a service
and as a back-up to the public and to the regulatory agencies.
Current research activities relating to land disposal are underway in each of
the following study areas:
a) Site evaluation and environmental impact assessment;
b) Landfill leachate migration and attenuation;
c) Landfill leachate control;
d) Standard procedures development;
e) Special wastes disposal on land; and,
f) Industrial waste management.
The objectives of this land disposal research program are to generate and evaluate
technical information on each of the above study categories which can be either
utilized in the preparation of specific technical guidelines or transferred to regulatory
agencies for their direct consideration. The intent is to further develop techniques
and procedures for improving waste management systems and enhancing environmental
protection technology.
This paper describes Fisheries and Environment Canada's research projects which
are currently in progress as part of the solid waste program on landfill, landfill
leachate, and industrial waste disposal research.
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INTRODUCTION
Research activities on solid waste
are carried out in Canada by a number
of Provincial Government agencies, a
variety of research institutes and
university groups, and a multitude of
industries, in addition to the Federal
Government.
This paper describes land disposal
research activities carried out by the
Federal Government, and in particular
the Department of Fisheries and the
Environment.
The Waste Management Branch is
currently undertaking a number of research
activities related to the discharge of
both municipal and industrial or
hazardous wastes onto land, in recogni-
tion of the need to improve existing
control or regulatory measures in order
to ensure proper and safe disposal of
wastes onto land.
Some of our responsibilities in
this regard are to develop technology,
to provide regulatory agencies in
Canada with technical information as a
back-up service to them, to develop new
or improved disposal guidelines, and to
develop methods for predicting and
monitoring environmental impacts of
proposed waste disposal schemes. The
results of our own land disposal
research program along with research
findings of others, will be used
accordingly. At the same time, our
research findings are also being made
available to a NATO/CCMS Pilot Study
on Disposal of Hazardous Wastes (1).
in which Canada is actively participating
along with the U.S. and several European
countries.
Our current research activities
pertaining to land disposal are underway
in each of the following study areas:
a) site evaluation and environmental
impact assessment;
b) leachate migration and
attenuation;
c) leachate control;
d) standard procedures development;
e) special waste disposal; and,
f) industrial waste management.
These activities are conducted on
a national basis through research con-
tracts administered by either this Branch
or our Regional office representatives,
often in co-operation with other federal
or provincial government organizations.
In this paper, some of our landfill
and landfill related research projects
will be briefly discussed.
LANDFILL STUDIES
Monitoring and Modelling Studies
Five landfills in southern Ontario
were the subject of a special in-depth
investigation of both the magnitude
of contaminant loadings to receiving
streams and the contaminant attenuation
afforded by the soils at the landfills.
The landfill sites vary in size from
6 acres to 78 acres (2.4 to 31.6
hectares) and contain from 6 million to
150 million cubic feet (0.17 to 4.3
million cubic meters) of waste. Several
of the landfills have received a large
variety of domestic, commercial and
liquid industrial wastes.
For each of the five sites, the
contractor prepared a complete descrip-
tion of the site; provided instrumen-
tation and sampling to examine ground-
water contamination; collected ground-
water and soils data; and, prepared
summary reports. Laboratory water quality
analysis work was performed by Environment
Canada.
The instrumentation of the study
sites was designed to yield information
for soil and groundwater characteriza-
tion and for ground water flow analysis.
Wells were drilled at each of the
five sites, and drill logs were prepared
during the drilling operation so as to
adequately identify the various soil
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strata encountered. All groundwater
elevations were recorded.
Soil samples were taken from the
major soil strata encountered. For
each landfill site, the major soil
types encountered were identified by
sieve analysis. Sufficient amounts of
each of the 5 soil types at the five
sites were collected for subsequent
laboratory soil analyses.
The wells were developed as moni-
toring points to allow extraction of
groundwater samples for chemical analysis.
To achieve this, they were fitted with
well screens attached to plastic or
steel pipe. In addition, some screens
were sealed such that the wells could
function as piezometers to yield data
on groundwater movement.
The monitoring wells were strate-
gically located at each site as nests
of two wells apiece. The piezometers
were placed within the saturated zone
in coarse-grained soils, where possible.
All sites required a well to be
placed into the buried refuse to the
base of the fill to yield samples of raw
leachate. All wells were adequately
flushed after placement to remove
contaminants introduced during drilling
and installation. They were capped but
perforated to prevent pressure build-up
within the well.
The groundwater monitoring program
required the measurement of water levels
and conductivity, and the withdrawal
of groundwater samples for chemical
analysis. Water levels and conductivity
readings were taken at all wells with the
former expressed as elevations in feet
above sea level. After these measure-
ments were taken, the wells were flushed
or bailed to waste a volume of water
equal to at least twice that standing
in the well.
Samples were then taken from all
wells, and field parameters measured.
The samples were further prepared,
including filtration when necessary,
and transported by the contractor to
the laboratory for analysis. A total
of 35 parameters including PCB's were
chosen at the outset, however this
list was reduced after a screening
analysis of the first set of results.
The data on water levels, conductivity
and water quality were collected and
reported by the contractor.
The hydrometeorological data
required for the study period included
precipitation, temperature, and eva-
poration. To monitor water infil-
tration and surface discharges of
leachate, a number of lysimeters and
weirs were also installed wherever
necessary.
Data on soil characterization was
required for identifying and classifying
the various soils encountered. The
specific tests which were conducted
provided information about the chemical
and physical properties of the soil
necessary to make this classification.
The manner in which the soils and
contaminants from the leachate
interact specifically with respect to
contaminant absorption (and/or
desorption) was of primary interest
in this study. While the study had
as its major objective the identifying
of the magnitude of contaminant flux,
it was also considered important that
the conditions under which the migration
occurs be documented so as to enable
the development of explanatory or
predictive migration models. The
data collected during soil characteri-
zations were inputs for this purpose.
The specific laboratory soils
analysis which were conducted included
the following:
(a) grain size analysis to allow
classification of soil samples and
to enable comparison between
samples using a standard system.
Smaller sized particles tend to be
more active in soil-leachate
interactions and thus classifica-
tion of soil into sizes was
required to examine this condition;
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(b) permeability measurement provided
information necessary to construct
models for groundwater movement.
Whereas it was desirable that un-
disturbed samples be used for
these analyses in the coarser soils,
undisturbed samples were difficult
to obtain. It was also thought
to be the case that, because of
anisotrophy, permeability measured
in the direction of drilling may
not be equivalent to the horizontal
permeability, and therefore field
permeabilities were measured
through a falling head test;
(c) clay minerology, since it appears
that clay size particles are the
most active in soil-leachate
interactions. The type of clay is
also significant and thus an analysis
of soils using X-ray defraction
techniques was also conducted;
(d) soil organic matter, which may
also be very active in contaminant
attenuation;
(e) soil cation exchange capacities
provided information specific
to reactions between the soil and
contaminants from migrating
leachate. The information will
be of use when explaining the removal
or release of cation contaminants
during the passage of leachate
through soil;
(f) soil resident ions, and total soil
chemistry analysis represents a
means whereby the adsorption and
fixation of contaminants may be
determined. By determining
resident ion content and total soil
chemistry, both before and after
exposure to leachate, differences
may be attributed to adsorption and
fixation (and/or desorption and
dissolution) of leachate contaminants;
and,
(g) organic carbon measurements which
will be used in a manner similar
to that described for the resident
ion analysis.
The results showed that four of the
landfills were found to be situated
on non-productive lands (former pits
and swamps) near major rivers and any
deleterious quality effects are restric-
ted to shallow, local groundwater flow
systems and to local surface water
courses. Soil attenuation is minimal
at these sites and leachate discharges
occur to nearby streams. The other
larger landfill, selected especially
for the collection of data for attenua-
tion studies, is situated in an area
where a large, shallow, groundwater flow
system can be influenced. Groundwater
moves about 3000 feet through surficial
sand and gravel before discharging to
streams.
All data collected, including ground-
water stage and quality measurements,
water infiltration and other climatic
data, has been tabulated in.a final
report (2). This report a.lso includes
descriptions of the hydrogeology of
each site.
The data is currently being evaluated
in a follow-up study which will attempt
to quantify contaminant loadings from
the landfills and which will also attempt
to numerically simulate contaminant
migration behavior utilizing both a
finite elements model and a modified mass
balance model patterned after Elzy's
work at the University of Oregon (3).
The results of this work indicates that
with the data on land, a predictive
ground water contaminant migration
model for use in extrapolating data
to predict future contamination
migration at these and other landfills
will be successfully developed. This
development will be documented in the
final report.
As a part of this contract, a state-
of-the-art document on ground water
contaminant migration modelling has
also been prepared (4).
Leachate Plume Migration and Attenuation
A much more in-depth study of
leachate migration and attenuation was
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initiated at the C.F.B, Camp Borden
landfill, which is situated within
a simple hydrogeological setting. Such
an almost idealized, simple setting was
thought to be conducive to testing new
approaches and techniques, and also
thought to offer an opportunity to
apply and evaluate numerical plume
migration simulation methods.
The landfill is situated approxima-
tely 60 miles north of Toronto within
a lowland physiographic unit. Most of
the area falls within a flat to gently
undulating "Camp Borden sand plain".
For the most part, this basin was at one
time part of a lake floor and its surface
sediments are therefore of deltaic and
lacustrine origin. These loose granular
materials have been, in general, well
drained by the entrenchment of the rivers
of the area, all of which drain to the
north, to Georgian Bay.
This 35-year-old, 14-acre landfill
appears to have been constructed in a
minor ravine that had been cut into the
regional sand plain.
Boreholes had been previously drilled
through the fill and around its boundaries.
These early holes were investigated to
maximum depths of 50 feet below surface
and encountered extremely uniform subsoil
conditions. Each of the borehole logs
showed stratified, fine to medium
textured, uniform sands. The size
gradation curves visually demonstrated
this uniformity. The coefficient of
permeability for the sands was estimated
to be in the order of 10-3 cm/sec.
A regional evaluation using water
well records showed that the sands below
the garbage probably extend to depths
slightly more than 100 feet at the site.
Below this, well records reveal a fairly
thick sequence of stratified lacustrine
silts and clays that in turn may be
underlain by glacial tills of this same
texture. These soils beneath the
surface sands then .probably act as an
aquitard due to their low permeability.
In effect then, the surface sands
were thought to be sealed hydraulically
at depth. Bedrock lies about 200 feet
below the present land surface buried
by the thick soil sequence.
Groundwater appears to flow in a
northerly direction, and laterally
within the surface sands. Thus precipi-
tation infiltrates the landfill in
nearly a vertical direction, and any
contaminants that are leached from the
solid waste migrate with this ground
water flow. The site receives
approximately 6.7 inches of average
annual water surplus, based on six
years of record. Actual precipitation
in the area is approximately 30
inches.
Given this prior information about
the landfill setting, a study approach
was chosen which would eliminate the
necessity for an expensive borehole
drilling program specifically to define
the hydrogeology prior to initiating
another drilling program for the esta-
blishment of suitable monitoring
points. Instead, it was decided to
use geophysical resistivity techniques,
using a wenner configuration with
electrode spacing of 65 feet, to map
the area! extent of contaminant migra-
tion, as well as to gain an apprecia-
tion of the relative severity (concen-
tration) of the contamination. Although
the resistivity surv'ey was not alto-
gether successful, it did provide a
suitable indication of the size of the
conductivity plume. A detailed three-
dimensional plume configuration was
then obtained by conductivity
profiling using a method of continuous
augering and sampling. This technique
employs a protected porous brass tip
secured to a hollow stem auger. Water
samples from any depth are withdrawn
under suction through tubing attached
to the brass tip and drawn through the
augers. Samples of water were taken at
5-foot intervals in each location
within the plume and field conductivity
tests performed continuously on each
sample. The data was used to plot the
vertical distribution of the specific
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conductance. By profiling conductivities
at several locations (cross-sections
across the area! extent of the contami-
nant plume) the 3-dimensional extent
of the contaminants in the subsurface
was mapped.
The results to date show that the
thickness of the sand varies from approx-
imately 20 ft. to more than 80 ft.,
with the depth to the water table ranging
from approximately 3 ft. to 33 ft. below
ground surface. Based upon the specific
conductance measurements, groundwater
contamination has been restricted to the
sand hydrostratigraphic unit and conta-
minants appear to have migrated a distance
of approximately 2000 ft. from the
landfill in the direction of ground-
water flow. Contaminants are within the
sand hydrostatigraphic unit moving over
top of the clay soils within the sand
hydrostatigraphic unit, with the main
flux of contaminants being about 40 feet
below the ground surface. Of particular
significance with respect to this project
is the uniformity in trends observed in
the distribution of specific conductance
values. The highest values were found
near the landfill and they decreased
consistently with distance from the
landfill. In addition, in vertical profi-
les the highest readings were found near
the centre of the contaminant plume
with consistent decreases with distance
above and below the centre of the plume.
Thus a well-defined and geometrically
simple contaminant plume appears to exist
at the site. The simplicity and regularity
of the plume is strong evidence of a
simple hydrogeologic setting. Although
this simplicity may not be typical of
landfill environments, it does provide
an ideal setting for the field study of
leachate attenuation processes and the
testing of numerical simulations proce-
dures for predicting the migration of
contaminants.
In order to establish a water
budget for the site, rain gauge and
evaporation pan equipment, water level
recorders, infiltration lysimeters, snow
level, and snow melt equipment was
installed at the landfill. The only
water quality parameter measured up to
this time is specific conductance.
Work is currently proceeding to complete
the description of the hydrogeologic
setting and to install a detailed network
of piezometers for monitoring of the
hydrogeologic conditions and ground-
water chemistry. Long term monitoring
of the detailed network will be under-
taken to determine contaminant levels
of certain selected parameters and to
provide data for the mapping of specific
contaminant enclaves.
Modelling Competition
Upon completion of the above
field work at C.F.B. Camp Borden,
it is anticipated that the results of
the study can be used to evaluate
predictive capabilities of ground
water contaminant migration models as
applied at landfills. Based on this
evaluation, the usefulness of such
models within a regulatory program can
be assessed.
The state-of-the-art of ground-
water contaminant migration modelling
has progressed to the point where
suitable models have been developed for
predicting the behavior of landfill
leachate contaminants within a well-
defined hydrostatigraphic unit inclu-
ding both unsaturated and saturated
zones. Most of these models are based
on a general solute transport equation
which can be stated as: (5)
in which the first term on the right-
hand side of the equation describes
the movement of the solute due to
dispersive effects, the next term
describes the movement due to convective
or bulk flow effects, and the last
term accounts for contaminant attenua-
tion. The variability in model capa-
city is attributed to both the manner
in which the equation is solved and the
make-up of the above attenuation term
or its equivalent.
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Other models are based on simplified
physical-conceptual representations of
the actual flow system, such as a chemi-
cal mass balance model simulating a
series of completely mixed reactors and
incorporating various sorption phenomena.
The desirability of utilizing some
model for predicting contaminant
migration, prior to the permitting of
waste discharges to land, has been
recognized by regulatory agencies.
Some agencies have attempted, unsuccess-
fully to date, to develop "black-box"
models for use in their regulatory
permitting system, while others apparen-
tly have simply requested that a permit
applicant be responsible for modelling
his proposed discharge system for
their adjudication. At a time when
models are untested, and many uncer-
tainties surround the use of such predic-
tive "tools", the above practices are
questionable.
If models have a place within
a regulatory program, they must be
tested for their predictive capabilities
given a realistic amount of information
which any permit applicant may reasonably
be expected to provide. If the models
require an excessive amount of detail
in-put, or if they are incapable of
providing answers without first having
to be calibrated to a particular situa-
tion through the undertaking of a complete
hydrogeological site investigation, or if
they are prohibitively expensive to
apply routinely, as would be necessary
within any regulatory program, then
clearly the models have proven to be
useless, and any further efforts at
progressing the state-of-the-art must
be reassessed.
All modelling groups who have an
interest in numerical simulation of
landfill leachate contaminant plumes are
invited to take the basic information
to be contained in the CFB Camp Borden
landfill study report, and to calibrate
their model to simulate current condi-
tions. Due to the absence of an
accurate in-put function, detailing
characteristics and quantities of waste
components in the landfill and their
historical rate of leaching and leachate
characteristics it is necessary to
define the present as the null condition.
Using the study data as in-put, all
participating modellers will be asked
to provide a series of predicted
contaminant migration patterns for
the site, which will be checked against
monitoring data to be routinely collec-
ted. Other than specific conductance
and chlorides, a parameter list for
monitoring has not yet been developed.
Furthermore, the'same modelling
groups may be provided information
about a new CFB Borden landfill, which
has been instrumented sufficiently to
allow continued monitoring, such that
the same calibrated model can be used
to develop predicted migration patterns
for this site in a somewhat more com-
plicated hydrogeologic setting.
The proposed duration for this
evaluation project is three years.
At the completion of this period,
predicted patterns will be compared
with actual patterns. Continued
monitoring will allow further compari-
sons in the future.
Peat Bog Landfill ing
A study is being carried out on a
landfill located in a peat bog type
of hydrogeological setting, to determine
the sub-surface movement of leachates
and the potential for contamination of
both the underlying aquifer and surface
water.
The landfill under investigation is
located in the Greater Vancouver area
in British Columbia. The 365~acre
site is the point of discharge for
municipal, commercial, demolition, and
other industrial and hazardous wastes.
It is situated within a corner of one
of the major peat bogs in the lower
mainland area of British Columbia,
and is probably a typical landfill
environment on deltaic deposits in that
region.
It was decided to carry out a
comprehensive evaluation involving the
investigation of the sub-surface geology
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by collating past bore hole information
and the installation pf piezometer and
monitoring wells for hydrog'eological
and sub-surface water chemistry
ingestigations. Additional and confir-
ming geological information was obtained
in conjunction with the well installa-
tions.
From previous geologic investi-
gations on the Richmond Landfill site,
there was considerable bore hole data
available. This data was plotted to
show the site stratigraphy. The
preliminary geologic setting develo-
ped indicated the site was situated
on peat and overlying deltaic deposits
of clay, silts and sands. The most
interesting aspect of the geologic
setting was its undulating strati-
graphic units. Peats ranged in thick-
ness from 5 to 20 feet.
Previous theories of leachate
movement had assumed a continuous
stratigraphy, with surface ditch
interception of the total leachate
flow. However, the geologic setting,
determined from the preliminary
evaluation of the geologic data,
indicated that there were significant
statigraphic highs and lows. This,
coupled with the known compressibility
of peat resulting from the landfill
loading, indicated that interception
of all the leachate by surface ditches
may not occur. Hence, a thorough
understanding of the hydrogeology
was required.
Based on the known geology, a
detailed drilling program was initiated
to provide further borehole information,
and to install monitoring wells for
static/piezometric ground water level
measurement and water quality monitoring.
The wells were located so as to
provide hydro!ogical and water chemistry
monitoring at the base of the refuse,
in the peats and below the clay. A
background control well was located
east of the landfill site. Piezometers
were constructed of a 2 foot X 2 inch
diameter plastic well screen, wrapped
with fiberglass tape, attached to
a 3-inch diameter plastic casing.
The monitoring activities on
site included ground water sampling
and analysis, drainage ditch water
sampling and analysis, precipitation
recording, and recording of tidal
fluctuations of the adjacent Fraser
River. Falling head or slug tests
were carried out to determine the
permeabilities of each hydrostati-
graphic unit, including the refuse.
The results of the study are still
being interpreted; however, it is
evident that there are three distinc-
tive statigraphic units, namely:
the refuse which developed combined
precipitation and tidal fluctuation
response; the peat which had a
piezometric level greater than that
in the refuse and which was apparen-
tly responsive only to fluctuations
of barometric pressure; and the
underlying sand aquifer, which again
showed tidal response. This infor-
mation would tend to indicate an
upward flow gradient in the peat unit;
however, it is thought that the high
piezometric levels in the peat are
a result of peat consolidation and
not of confined flow. Indications
are also that the confining clay
layer appears to retard leachate
migration to the lower aquifer,
although this is very much dependent
on the substained integrity and
continuity of the clay layer. There
are indications that the clay layer
is interspersed with sandy lenses
which appear to be hydraulically
connected to the lower aquifer.
Some of these lenses may be exposed
during the operation of the landfill.
Water quality evaluations indicate
that leachate has not contaminated
the underlying silty sand aquifer.
Most leachate appears to flow towards
and collect in the adjacent surface
drainage ditches,.which discharge
directly to the Fraser River,
although there is also significant
flow away from the fill into uncon-
solidated peat layers. The unconso-
lidated peat, with a permeability
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of 10 cm/sec., is thought to have
significant attenuation capabilities.
An interim report (6) has been
prepared and is currently being revised
and up-dated.
Leachate Recirculation
Another west coast landfill,
situated on Vancouver Island north of
the Greater Victoria area, is under
investigation to determine the feasibility
of leachate recirculation, over an
extended period of time and under
annual excess moisture conditions.
A study program was designed
specifically to provide data on the
effects of leachate recycle onto an
existing major landfill. It will produce
information which can be used at other
sites as well as information specific
to the test site. Information will be
obtained in the following areas:
a) quantity of leachate emitted
by the fill;
b) rate of fill stabilization;
c) disposal of water by evaporation
and evapotranspiration; and,
d) use of the fill as a capaci-
tance during peak flows of
leachate.
It is recognized that a considerable
amount of work (7,8) has been done
elsewhere on the recycling of leachate
which has shown that recycling under
controlled conditions can accelerate
stabilization of landfills and reduce
contaminants in the leachate. It has
also been found that heavy metals tend
to build up in the leachate. The
previous results are sufficiently
encouraging to consider a full-scale
field test on an active sanitary
landfill. The study proposed extends
the previous work to full-scale.
The Hartland Road landfill
started receiving waste in 1959 and
was operated for eleven years by open
burning. Open burning was prohibited
in 1970 and since that time the facility
has been operated as a sanitary
landfill.
The site is located in a bedrock
saddle of igneous rock which forms a
containment structure from which the
only escape for surface water and
leachate is a narrow channel. The
landfill now covers about 40 acres,
with a maximum waste depth of about
120 ft. The top of the fill is
about 100 ft above the top of the fill.
The area receives about 40 inches
per year of precipitation, primarily
during the winter months, and this
results in a leachate flow rate varying
between virtually nil and 200,000 imp.
g.p.d. with an average flow of about
500,000 imp. g.p.d.
In this study, which is just
getting underway, it is proposed to
recycle leachate by spray onto the
surface of the completed portions of
the fill to accomplish the following:
1. dispose of water by evaporation,
evapotranspiration and absorption
into the fill;
2. achieve treatment of the leachate
on and in the fill, and,
3. accelerate stabilization of the
fill area.
The study program is designed to
establish relationships between spray
application rate and retention capacity
of the fill, evapotranspiration with
selected ground cover, removal of BOD
and COD, iron removal, tannin and phenol
removal and the fate of heavy metals.
The program will continue over
an initial three-year period assuming
that equilibrium conditions are
approached and that adequately represen-
tative data are obtained. The study
may continue beyond that if fill
equilibrium conditions cannot be
established in this time.
The recirculation system and the
landfill will be monitored by a variety
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of activities which include sampling
the leachate discharge, sampling well
points within the refuse, measuring
fill settlement, and recording climatic
data and fill temperatures.
The data to be obtained during the
initial three year monitoring period
will be used to determine the following:
a) Effect of recycle on leachate
volume. Liquid input to the landfill
will consist primarily of precipitation,
recycled leachate and such intrusion
water as escapes a surrounding interceptor
system. The liquid output will consist
of evaporation and evapotranspiration,
and leachate discharge from the system.
Ideally, this discharge to a stream is
not a problem.
It is not always possible to match
precipitation and rainfall and so the
planned capacity of the fill for retaining
liquid to compensate for inequalities in
input and output becomes very important.
The study will provide a water mass
balance showing what performance may be
expected under the test conditions.
It is intended that a model will be
prepared relating the input capacity
and output under various exposure
conditions.
b) Effect of recycle on leachate
quality. The composition of leachate and
the absolute amounts of each component
will be investigated as a function of
recycle rate. The principal changes in
leachate composition should occur in the
organic constituents. Inorganic compo-
nents are expected to be less affected,
although iron will be removed continually.
As the interior of the fill changes from
anaerobic to aerobic the organics should
be destroyed more rapidly and the fill
should stabilize more rapidly. The
initial effect may be an increase in BOD,
COD, and inorganics followed by a longer-
term decrease in all parameters. It is
the intent of this study to establish
what course these parameters follow
once recycling is instituted. Previous
studies have shown a long-term decrease
in BOD and COD with controlled water
addition. The effect of recycling variable
amounts of leachate, highly aerated,
is not known. The data obtained will
indicate what improvement in quality
can be anticipated and what limitations
may exist on recycle rate and leachate
quality.
c) Effect of recycle on bacterial
population.
d) Effect of recycle on soil
cover vegetation. Within the scope
of the study, the effect of recycling
on the ability of grasses, shrubs
and trees to survive and grow will
be qualitatively evaluated.
e) The fate of heavy metals. It
has been suggested that many heavy
metals such as arsenic, lead, zinc, etc.
build up in recycled leachate. If there
is a net discharge of leachate, such
build-up is undesirable. The extent
and nature of such accumulations will
be established.
f) The rate of stabilization of
the fill as judged by gas evolution
and composition, and settlement of the
fill.
g) Effect of recycle on net
volume of effluent discharged from the
fill site.
The data which will be obtained
will be applicable to any landfill at
which leachate recycling may be either
a feasible additional means of control
of leachate discharges or a desirable
alternative to treatment of leachate
by chemical and biological means.
There is no data available at this
time for further discussion.
SOIL-WASTE INTERACTIONS
Study Objectives
The main objective of our soil-
waste interaction study program,
involving several soil-waste projects,
is to develop a means for predicting
the attenuation and mobility of liquid
or solubilized industrial wastes in
soils, by investigating the soil-waste
interactions in both saturated and
34
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unsaturated ground water regimes.
Whenever it is proposed to discharge
industrial wastes to the land, it would
be desirable to be able to predict
the behaviour of the waste or its
leachate within the soil system at the
outset, and to predetermine the impact
of the proposed discharge on the receiving
environment.
At present, there is a need to
study the mechanisms affecting waste
attenuation and migration within the
soil, and to develop quantitative
information which can be used, directly
or by extrapolation, to make the above
assessments. When the data has been
collected, it must be manipulated
into a usable and workable form. This
requires the development of a procedural
format which can be used as a decision
making "tool".
With this "tool", it should be
possible for a regulatory agency to
immediately assess any industrial waste
disposal scheme involving a discharge
to land, given the waste characteristics
and the soil characteristics.
Li terature Revi ew Regort
The first step towards this objec-
tive was to conduct a state-of-the-art-
review, which was intended to provide
background information for follow-up
soil studies involving specific soil-
waste interactions.
The specific objectives of the
review study were to: review the litera-
ture on soil study techniques, waste
attenuation mechanisms and factors affec-
ting same, and contaminant migration as a
result of the attenuating mechanisms
involved; report on documented cases
of ground water pollution resulting
from industrial including hazardous
and toxic waste discharges; and on
the basis of the above, outline areas
requiring further investigations.
In the resulting report (9),
a review of the literature on the
contamination potential of wastes
in the soil-waste environment is
presented. A conceptual model which
integrates critical factors and proces-
ses affecting the attenuation,
migration and fate of waste conta-
minants in soil is also discussed.
The report critically reviewed
mathematical models.which have been
developed for the evaluation of the
movement and fate of chemicals in the
soil. The significance of particular
soil study techniques is also
discussed. Finally, documented cases
of ground water pollution caused by
discharge of specific industrial wastes
are presented.
Soil-Waste Interaction Matrix
At the same time that the litera-
ture was being reviewed, a framework
for the decision making "tool" was
being developed, in the form of a
generalized soil-waste interaction
matrix which can be readily used as
a simple means for assessing proposed
industrial waste disposal sites. The
matrix is to enable waste disposal
recommendations to be made consistent
with good land use practice and in
accordance with acceptable environmental
criteria.
The objective of the matrix
development was to select a ranking
scheme for wastes and a ranking scheme
for soil-sites, and to combine these
in a quantitative way in order to
arrive at a disposal ranking for any
waste soil-site combination. Achieve-
ment of this objective depended upon
both selection and weighting of waste
and soil-site parameters.
After the various waste charac-
teristics and soil-site characteristics
were defined, they were scored in
points or arbitrary units. Each
waste and each soil-site was then
35
-------
defined by a set of parameters. The
waste parameters and the soil-site
parameters become rows and columns in a
matrix format. A description of the para-
meters and methods for calculating the
various parameter values and for deter-
mining and utilizing matrix scores, as
well as a complete description of the
development of the matrix is contained
in the final study report (10).
Both a site dependent and a site
independent matrix were developed, the
latter being a mini-matrix within the
main matrix. The site independent
matrix was intended to consist of rows
of waste characteristics and columns of
soil types. Basic attenuation information
could be developed as in-put to the mini-
matrix, and this information as a mini-
matrix could then be used as direct in-
put to a site-specific matrix, without
having to constantly develop new site-
specific information, even though
experimental procedures for parameter
quantification are defined in the
report.
The matrix procedure is currently
being tested, and at this time it appears
to be a major contender in the ring of
possibles for the U.S. EPA's attenuation
procedure development work.
Batch Reactor Soil Study
As an alternate procedure for in-
depth investigation of soil-waste interac-
tions, and as a procedure which is capable
of generating data for use in the above
matrix procedure, the dispersed soil batch
reactor technique developed at the Univer-
sity of Waterloo was tested with
industrial waste. The test procedure
used to study the attenuation and desorp-
tion of the waste liquids under anaerobic
conditions, involved the sequential
contacting of the soil and waste,
followed by the desorbing water in a
series of five dispersed soil reactors
reflective of liquid movement through
varying depths of soil. It is a deviation
from the more traditional techniques
involving soil column experimentation.
The laboratory procedure is
described in detail in the final study
report (11). With the resulting data,
the mass of contaminant attenuated
and desorbed was calculated by perfor-
ming a mass balance calculation in
each reactor for the contaminant
examined.
The effectiveness of dispersion by
soil water as an attenuation process
was studied using chloride ion. It
was possible to distinguish between
attenuation due to dispersion and
attenuation due to other mechanisms such
as precipitation, mechanical filtration
and sorption. It was shown that disper-
sion is a major mechanism of attenuation.
The desorption of contaminants in the
soil reactors was most effective for
those contaminants attenuated primarily
by dilution. For those contaminants
attenuated primarily by mechanisms
other than dispersion, desorption was
found to be limited.
This method of study permits the
evaluation of a zone of influence of
a liquid waste disposal operation.
Thereby guidance for the selection
and operation of waste disposal sites
is provided.
SPECIAL WASTE DISPOSAL
PCB Attenuation in Soils
A modification of the dispersed
soil batch reactor procedure is being
currently utilized in a study of the
attenuation of Aroclor 1016 and Aroclor
1245 in soils. The soils vary in clay
content, pH, cation exchange capacity,
and organic matter content.
This study is designed to provide
some basic information on the behavior
of PCB's in soil under anaerobic
conditions. It is known that a variety
of PCB materials have been discarded at
landfills across the country, and PCB's
have been detected in landfill leachates
in the parts per billion concentration
range.
36
-------
The study is scheduled for comple-
tion by June, 1977, Thereafter it is
likely that a variety of other hazardous
materials will be investigated in a
similar fashion. The wastes of most
concern at this time appear to be
arsenic, mercury, phenols, and persis-
tent organics.
Septic Tank Sludge Landfill ing
The proper disposal of septic
tank sludge also remains a problem.
The raw sludge is generally not accep-
table for discharge into a municipal
sewer system, and simple sludge lagoo-
ning is also generally unsuitable in
many locations. A significant quantity
of this waste has been going into
landfills, although recent concern
about this practice on the effect of
landfill leaching has caused many
local authorities to disapprove of
such practice.
The effect of septic tank sludge
additions to municipal refuse was
studied at the University of British
Columbia, as part of a landfill
leaching investigation conducted for
the Province of British Columbia. It
was shown in this preliminary work that
the addition of septic tank sludge to
mixed municipal refuse could signifi-
cantly reduce the concentrations of
contaminants in the leachate, under
certain conditions(12).
If these preliminary findings
could be confirmed, this would indicate
that the discharge of raw sludge to
landfills may be an environmentally
sound practice. A follow-up
study was initiated.
The objective of this study was to
identify a range of application rates
at which septic tank pumpings can be
discharged to a landfill without
increasing leachate contaminant loadings
to a receiving environment.
There appears to be a ratio of sludge
weight to refuse weight above which
an improvement of leachate quality
will occur, and below which poorer
leachate quality results. The deter-
mination of such a rate breakpoint
would be required for design conside-
rations.
The current lysimeter study is
designed to investigate the behavior
of varying sludge additions on leachate,
under varying conditions of rainfall
application and refuse depth.
Leachate is being analyzed for a
minimum of 24 parameters, including
total and faecal coliforms. The
preliminary data appears to be confir-
ming the previous findings that sludge
additions can reduce peak contaminant
concentrations by 40 to 100%. It
appears that total masses of contaminants
discharged are being reduced as well.
It was noted, however, that at
the greater infiltration rates (45
inches per year) the peak concentrations
are not reduced to the same extent.
Therefore, increasing precipitation
rates would appear to offset a fraction
of these reductions. With only very
early results available, it is premature
to present a complete analysis at this
time. The work is scheduled for comple-
tion this fall.
PROCEDURES DEVELOPMENT
Recommended Procedures Documents
The Waste Management Branch is
currently reviewing methodologies for
waste disposal site investigations and
for site environmental protection systems
design as part of our landfill research
program. One of the objectives of
this program is to develop a series of
guideline documents on various recommen-
ded procedures, based on current
technology and current thinking.
37
-------
Landfill Leachate and Gas Monitoring
A. series of international round-
table discussions was initiated to
assist ourselves in documenting the
current state-of-the-art, and in
developing recommended procedures
documents. To date, we have sponsored
four separate sessions, each of which
have been well attended by invited
experts from government regulatory
and research agencies, from consulting
firms and universities, and from the
waste disposal industry, in Canada, the
U.S., and abroad.
The first session was held in
April, 1975 in Vancouver, to deal with
the topic of landfill leachate analysis.
A report on recommended procedures
for the analysis of landfill leachate,
based on a consensus of opinion obtained
from the delegates at the Vancouver
session, was issued in October, 1975 (13).
A second session, dealing with
ground water and soil sampling proce-
dures was held in Ottawa in September,
1975. The session was held to exchange
views and information on sampling
techniques, and to obtain a consensus
of opinion on methodologies which should
be applied to the conduct of future
landfill leachate migration studies,
ground water quality monitoring programs,
or any other investigations concerning
the environmental impact of landfill
leachate on ground water. A June,
1976 report presents recommended
procedures based on the session procee-
dings (14).
Two other sessions have been
recently held, one in Toronto to
deal with procedures for the design
and implementation of landfill moni-
toring programs, and the last one in
Montreal which dealt with landfill gas
detection, sampling, control, and
extraction methodologies. A draft
report based on the monitoring seminar
is currently under review, and a report
on the proceedings of the gas seminar
should be received soon. Each of these
reports will be used in the prepa-
ration of additional recommended
procedures documents.
Leachate Toxicity Measurement
A specific procedure being
developed is the measurement of
leachate toxicity. Toxicity has
often been suggested as a valuable
indicator parameter in any moni-
toring of surface waters receiving
landfill leachate discharges.
However, standard bioassay procedures
are expensive and generally require
large volumes of effluent, and may
take up to three days per sample.
A rapid toxicity procedure has been
developed to overcome these problems,
and it has been demonstrated to be
a less expensive, valuable field
monitoring procedure.
The procedure, which is called
the residual oxygen bioassay or the
rapid toxicity assessment, was
developed and tested in British Columbia
at the Richmond peat bog landfill,
utilizing a mobile lab unit inside
a van.
All bioassays were conducted
with 1.0 - 2.0 g. rainbow trout
(Salmo gairdneri Richardson). Leachates
were adjusted to pH 7 as required
with HC1 or NaOH prior to introducing
test fish. The temperature maintained
during bioassay was that of the holding
tanks. Samples were aerated prior to
bioassay to ensure that initial
dissolved oxygen levels were greater
than 90% saturation. Fish were not
fed for 48 hours prior to starting
the bioassays nor for the duration of
the test. One or more control vessels
of dechlorinated tap water was run
for each bioassay.
Residual oxygen bioassays were
carried out using serial dilutions
of effluent in BOD bottles (300 ml).
A selected number of test fish were
placed in each bottle to give a
38
-------
loading density of 4.5 to 6.5 grams per
liter. The bottles were stoppered with
a water seal and incubated until all
the fish in a test bottle had expired.
Each bottle was removed from the bath
after complete mortality and the dissolved
oxygen was measured using a YSI model
54 oxygen probe or Delta Oxygen probe
with stirrer.
Residual dissolved oxygen levels
were plotted against effluent con-
centration on double logarithmic paper.
By resolving the data on log-log scale
into two groupings, a best fit straight
line can be plotted for each group.
One line has a zero slope,the "no-
effect" or control line, and reflects
the unimpaired ability of test fish to
consume dissolved oxygen to control
values. The second line, the "effect"
line, has a positive slope where the
toxicant had a limiting effect on oxygen
utilization by the fish. The toxicant
or effluent concentration at the inter-
section of these two lines is defined
as the Threshold Limit Value (TLV).
Further details on the use of the
procedure to evaluate toxic or non-
toxic conditions in the field are
provided in the final study report (15).
The threshold limit values obtained from
the rapid procedure were directly
comparable to static 96-hour LC50
bioassays obtained by standard methods.
Municipal Waste Disposal Site Selection
Our other procedure development
work includes the generation of a
standardized simple, yet comprehensive,
municipal waste disposal site selection
procedure. The development of this
systematic site selection procedure,
which is intended primarily to assist
small municipalities, is based on our
evaluation of currently existing
procedures, and also uses a matrix
format. At this time it is anticipated
that the procedure will involve an
environmental protection matrix, a
public protection matrix, an operational
and management matrix, and' a final decision
matrix. The procedure will identify a
sequence for matrix evaluation and
site suitability scoring,
A final draft report on the
procedure should be received by the
end of March, 1977.
Waste Disposal Guidelines
Our last effort to be briefly
mentioned in this paper relates to
developing general guidelines for
the disposal of various wastes onto
land. In addition to preparing guide-
lines for specific wastes, such as
wood wastes, septic tank sludge, etc.,
we are currently reviewing policy
options in preparation for the deve-
lopment of overall guidelines on the
discharge of municipal and industrial
wastes.
REFERENCES
1. Mooij, H., "Report on Landfill
and Industrial Waste Management
Research Program: Part 1.
Completed Studies & Part 2.
Current Studies", report prepared
for NATO/CCMS Pilot Study on
Disposal of Hazardous Wastes,
Landfill Research Sub-Project,
September, 1976.
2. Hydrology Consultants Limited,
"Hydrogeologic Investigation to
Determine Landfill Contaminant
Migration in Three Great Lakes
Drainage Basins" report prepared
for the Solid Waste Management
Branch, Environment Canada under
contract no. SS02. KE204-4-EP60,
July 1976.
3. Elzy, E, et al_, in "Disposal of
Environmentally Hazardous Wastes",
task force report for the Environ-
mental Health Sciences Center,
Oregon State University, December
1974.
39
-------
(4) Sykes, J.F., et_a]_, "Groundwater
Contaminant Modelling - State of
the Art", draft report submitted
to Solid Waste Management Branch,
Environment Canada, July 1976.
(5) Cherry, J.A., Gillham, R.W. &
Pickens, J.F., Geoscience Canada
2,(2) 76 (1975).
(6) McAlpine, H.F. & Soper, P.M.,
"Richmond Landfill Assessment
Study: Interim Report", Federal
Activities Pollution Abatement
Group, Environmental Protection
Service, Department of Fisheries and
The Environment, Pacific Region,
December 1976.
(7) Emcon Associates, "Sonoma County
Refuse Stabilization Study, Third
Annual Report", County of Sonoma
Department of Public Works, July
1974.
(8) Pohland, F.G., in "Gas and Leachate
From Landfills", U.S. Environmental
Protection Agency, Office of Research
and Development, Municipal Environ-
mental Research Laboratory, report
No. EPS-600/9-76-004, March 1976.
(9) Phillips, C.R. & Nathwani, J.,
"Soil-Waste Interactions: A State-
of-the-Art-Review", Solid Waste
Management Report EPS 3-EC-76-14,
Environmental Conservation Direc-
torate, Environment Canada, October
1976.
(10) Phillips, C.R., "Development of a
Soil-Waste Interaction Matrix",
Solid Waste Management Report
EPS 4-EC-76-10, Environmental
Conservation Directorate, Environment
Canada, October 1976.
(11) Farquhar, G.J., & Rovers, F.A.,
"Liquid Industrial Waste Attenua-
tion in Soil", report prepared for
Solid Waste Management Branch,
Environment Canada, under contract
no. OSS4-0288, May 1975.
(12) Cameron, R.D., Phelps, D.H. &
McDonald, E.C., "Investigation of
Leaching from Simulated Landfills,
Progress Report No. 1."
Dept. of Civil Engineering,
University of British Columbia,
prepared for the Government of
the Province of British Columbia,
Department of Lands, Forests and
Water Resources and the Pollution
Control Branch, July 1975.
(13) Mooij, H., Cameron, R.D., &
McDonald, E.C., "Procedures for
the Analysis of Landfill Leachate",
Solid Waste Management Report
EPS-4-DC-75-2, Environmental
Conservation Directorate, Environment
Canada, October 1975.
(14) Mooij, H., & Rovers, F.A.,
"Recommended Ground Water and
Soil Sampling Procedures",
Solid Waste Management Branch
Report EPS-4-EC-76-7, Environmental
Conservation Directorate,
Environment Canada, June 1976.
(15) Vigers, G., "Leachate Toxicity
Measurements Using the Residual
Oxygen Bioassay Method",
Solid Waste Management Branch
Report EPS-4-EC-76-11, Environmental
Conservation Directorate, Environment
Canada, December 1976.
40
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THE EFFECTS OF INDUSTRIAL SLUDGES ON LANDFILL LEACHATES AND GAS
D. R. STRENG
SYSTEMS TECHNOLOGY CORPORATION
P.O. Box 24016
Cincinnati, Ohio 45224
ABSTRACT
In an effort to assess the impact of the practice of co-disposal of
industrial waste materials with municipal solid waste, a project utilizing
large scale experimental landfill test cells was undertaken. Concern has
been voiced that the addition of industrial wastes may result in the
occurrence of various toxic elements in leachates and thereby pose a poten-
tial threat to potable ground water supplies.
The combination of municipal solid waste and various solid and semi-
solid _ industrial residuals was added to several field lysimeters. All
material flows were accurately measured and characterized for the continu-
ing study. Data are presented on the mass flows for various chemical para-
meters within the generated leachates. Statistical evaluations were
performed and the resulting data are discussed. Also, included are data on
gas production and composition, as well as microbial activity.
INTRODUCTION
The disposal of industrial waste
materials has been a matter of con-
cern for some years now. All indus-
trial waste residuals are not
hazardous wastes, and, therefore
some may be amenable to co-disposal
with municipal solid waste. One
aspect of this project has been to
determine if certain selected indus-
trial residuals were suitable for
disposal in municipal landfills.
These wastes were evaluated with
respect to their effect on the
decomposition of municipal solid
waste, their effect on leachate and
gas quantities and compositions, and
their effect on microbial activity.
APPROACH
In an effort to evaluate the
effects of the co-disposal of
selected industrial waste materials
with municipal solid wastes, large
scale experimental landfills,
were monitored.
The test cells (experimental
landfills), employed for this study
were epoxy coated steel, 1.8m (6ft)
in diameter and 3.6m (12ft) in
height; capable of holding approxi-
mately 3000kg (66001bs) of municipal
solid waste in a manner comparable
to large area landfills. The size
of the test cells was selected to
minimize the problems of scaling
factors generally associated with
smaller laboratory lysimeters and to
avoid the use of shredded refuse.
Five (5) of the industrial waste
test cells (cells 9, 10, 12, 13 and
14) were located outside and one of
the industrial waste test cells
(cell 17} was located in an enclosed
bay area where higher ambient
temperatures were maintained.
41
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Prior to placement of any solid
and/or industrial wastes, a layer
of silica gravel, 300m deep, was
placed in all cells as a base for
the solid waste and to allow leach-
ate to permeate to the drain system.
All test cells were coated with coal
tar based epoxy paint which was
proven to be resistant to leachate.
All test cells were loaded simulta-
neously in a period of five days.
Municipal solid waste from the
City of Cincinnati was obtained
directly from the packer truck for
use in charging the test cells.
Solid waste was placed into the test
cells in 363kg (SOOlb) increments.
The industrial residuals being
evaluated were placed in the test
cells simultaneously with the solid
waste in every lift except the
first. After each increment of
waste was added, the solid waste or
the solid waste/industrial waste
mixture was mixed manually. Each
lift was compacted to a height of
300mm (1ft) and a density of 470kg
per cubic meter (SOOlb per cubic
yard). This loading sequence was
repeated eight times for each test
cell to provide 2.4m (8ft) of com-
pacted solid waste. The fully
loaded test cells were then covered
with 300mm (1ft) of compacted clay
and all cells were sheltered from
both moisture and sunlight.
Temperature monitors were installed
throughout all cells and in the soil
at various locations. Water addi-
tion to the cells is at a rate of
406mm (16in) per year and is
accomplished on a monthly basis in
accordance with anticipated net
infiltration for the midwestern
portion of the country.
INDUSTRIAL RESIDUALS BEING EVALUATED
The industrial process residuals
studied included a refinery sludge
(RS), a battery production waste
(BPW), an electroplating waste (EW),
an inorganic pigment waste (IPW), a
chlorine production brine sludge
(CPBS), and a solvent based paint
sludge (SBPS). Physical character-
istics and amounts of industrial
wastes added to each of the test
cells are provided in Table I.
Notable components of the
sludges were: copper, iron, mercury
and moisture for the refinery
sludge; copper, iron, cadmium, lead,
asbestos, tin, antimony and moisture
for the battery production waste;
chromium, iron, arsenic, cadmium,
cyanide and moisture for the
electroplating waste; beryllium,
chloride, asbestos, clay volatile
fibers and moisture for the inor-
ganic pigment waste; and nickel,
lead, chloride, asbestos, mercury
and clay volatile fibers for the
chlorine production brine sludge.
A complete chemical analyses of
these waste materials is shown in
Table 2.
SAMPLE COLLECTION
AND ANALYTICAL METHODOLOGY
Accurate and precise determinations
of chemical parameters on landfill
leachates have always been difficult.
In an effort to retain anaerobic
conditions, all leachates were
collected under an argon atmosphere.
With only several exceptions, the
analytical methods as described by
Chian and DeWalle1, and those
recommended by Environment Canada^,
were followed. Several modifica-
tions to these methods were employed
but will be discussed in more detail
by Mr. Richard Carnes. Precision
and accuracy were determined for
many of the chemical parameters
being evaluated. With the exception
of oxidations-reduction potential and
volatile organic acids the analyti-
cal determinations proved quite
precise and accurate.
Accurate determination of gas
quantity and composition proved
even more difficult than the
chemical analyses. We had noticed
gas permeation in several of the
experimental landfills. This leak-
age was a result of several factors,
the most significant of which was
the permeability of the materials
used in the construction of the test
cells. A permeability study of the
construction materials indicated
that all polymeric materials used in
the test cells were permeable to
many of the gases being produced at
the flow rates we were experiencing.
42
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TABLE 1. INDUSTRIAL WASTE PHYSICAL CHARACTERISTICS
Cell
9
10
12
13
14
17
Waste Type
RSC
BPW*1
EWe
IPWf
CPBS8
SBPSh
Moisturea
Content
79.00
89.25
79.53
51.75
24.11
24. 751
Amount Added"
1518
1291
1191
1420
2039
1604
Characteristics
High bacterial activity,
black moist
Grey-lg amount of
liquid
Brown , soupy
Black, solid, no odor
Very dense, no odor,
light brown, moist
Red to white color,
putty consistency, strong
odor
Percent by wet weight.
V
cRefinery Sludge.
Battery Production Waste.
e£lectroplating Waste.
fInorganic Pigment Waste.
^Chlorine Production Brine Sludge.
^Solvent Based Paint Sludge.
Stainly organic solvents.
43
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TABLE 2. INDUSTRIAL WASTE CHEMICAL ANALYSIS*
Waste Cell Number
Total Solidsh
Total Volatile Solidsh
Moisture11
Cr
Ni
Cu
Fe
As
Be
Se
Cd
Cn
Pb
Clh
Asbestos^
Hg
Sn
Sb
Clay Volatile Fibers^
Zn
V
B
Ti
RSb
9
21.00
31.00
79.00
125
23
35001
5560
1.0
4.8
26.0
0.50
1.0
182
2.35
3.00
10.6
NAk
NA
40.0
NA
7.20
NA
BPWC
10
10.75
7.94
89.25
155
32
1125
2950
72
1.8
180
29.0
4.2
3.48h
1.12
208
4.80
6800
1.32h
720
120
8.10
NA
EW*1
12
20.47
8.98
79.53
1.56h
35
100
1.37h
460
0.25
4.50
38.5
460
267
1.35
23.0
14.7
NA
NA
86.0
NA
19.0
NA
IPWe
13
48.25
22.25
51.75
0.50
10
110
1000
3.4
20.2
16.0
10.5
3.4
120
10.0
45.0
7.60
NA
NA
185
40
28.5
NA
CPBSf
14
75.89
1.17
24.11
5.00
65
125
2000
14.5
<1.0
16.5
0.70
14.5
697
20.0
110
227
NA
NA
480
NA
1.70
<0.1
SBPS8
17
75.25
55.31
24.75
75.0
0.5
2.0
150
12.8
<1.0
7.60
0.50
12.8
12.6
0.75
9.00
16.7
NA
NA
65.0
NA
11.4
NA
aAll values in ppm unless otherwise specified.
bRefinery Sludge.
°Battery Production Waste.
^Electroplating Waste.
elnorganic Pigment Waste.
^Chlorine Production Brine Sludge.
^Solvent Based Paint Sludge.
^Percent by wet weight.
^Underlined values indicate maximum sludge concentrations.
jFibers/100 g.
kNot analyzed.
44
-------
Since the test cells were placed
outside and below the ground level,
it was impossible to correct many of
those problems. The experimental
landfills placed in the bay area
however, have been sealed and
volumetric collection of gases has
proceeded. The ability of landfill
gases to permeate polymeric mate-
rials is significant and should be
considered a factor in the assess-
ment of synthetic liners for actual
land disposal operations.
Determination of gas composition
was accomplished employing gas
chromatography with thermal conduc-
tivity detectors. Analysis of gas
samples should begin immediately
after collection since error is
introduced when samples are stored
in the collection vessels. This is
due to the permeability of the
access septum to various gaseous
constituents.
LEACHATE COMPOSITION
Since the composition of leachate
emanating from the solid waste only
and solid waste/industrial waste
test cells has been discussed in
previous papers3f4 it will only be
briefly described here. Chemical
analysis of leachates from the solid
waste only test cells and those con-
taining industrial wastes admixed
with municipal solid waste shows
very little variation for organic,
nutrient and demand parameters.
Figure 1 indicates the typical dif-
ferences encountered in the total
organic carbon removals between the
municipal solid waste only test cell
and those containing municipal and
industrial waste mixtures. The
exception to this is the refinery
wastes, which has shown considerably
lower values for both total organic
carbon and chemical oxygen demand,
Figure 2. This ambiguity in the data
will be discussed in more detail in
a subsequent section.
Figure 2 shows typical mass
flows for chemical oxygen demand
(COD). Once again, similar
results are obtained for the
municipal solid waste only test
cells and those containing the
industrial waste additions. Graphi-
cal displays of total Kjeldahl
nitrogen (TKN) are shown in
Figure 3. Again, the industrial
waste/solid waste test cells behave
in a comparable manner to the solid
waste only test cells.
One point which must be made at
this time is that the solid waste
only test cell has received twice
the amount of water that the
industrial waste test cells have.
This comparison is necessary because
of the high initial moisture content
present in the industrial wastes
which has effectively reduced the
amount of infiltrating water re-
quired to reach field capacity.
Graphical displays for various
metallic ions are given in Figures
4, 5 and 6. Analysis of the
leachates for many of the-metallic
ions present in the industrial wastes
has indicated considerable variation
between the test cells. This vari-
ability j.n leachate composition is
relatable to the initial chemical
composition of the industrial waste
itself. For example, the lead con-
tent of the battery production waste
was considerably higher than that for
the municipal solid waste. We would,
therefore, expect to see higher con-
centrations of lead within the
leachate of this test cell. These
assumptions have been borne out.
Analysis of the industrial
waste/solid waste leachates for
highly toxic components, such as,
hexavalent chromium and methyl
mercury, indicates slightly higher
concentrations present ,in some of
the leachates. These concentrations
however, are in the low ppb range and
we have not been able to success-
fully evaluate their statistical
significance.
STATISTICAL EVALUATION
Correlation coefficients have been
determined for a number of analyti-
cal parameters. Parameter concentra-
tions were normalized by leachate
volume and then compared from cell
45
-------
UJ
ay
<
h-
=l
10
10"
BATTERY PRODUCTION WASTE PLUS
MUNICIPAL SOLID WASTE -CELL10
i i, i i i i I i i i i
1 3 5 7 9 11 13 15 17 19 21 23
25
TIME IN MONTHS SINCE CELL INSTALLATION
REFINERY WASTE PLUS MUNICIPAL
SOLID WASTE • CELL 9
TIME IN MONTHS SINCE CELL INSTALLATION
10
o. 10
o
0-
MUNICIPAL SOLID WASTE - CELL 4
CHLORINE PRODUCTION BRINE SLUDGE
PLUS MUNICIPAL SOLID WASTE - CELL 14
5 7 9 11 13 15 17 19
TIME IN MONTHS SINCE CELL INSTALLATION
23
FIGURE 1. TOC REMOVED THROUGH LEACHING
46
-------
10
10
g
0
-2
Q 1CT
O
O
10
-8
r
MUNICIPAL SOLID WASTE - CELL 4
BATTERY PRODUCTION WASTE AND
MUNICIPAL WASTE • CELL 10
5 7 9 11 13 15 17 19
TIME IN MONTHS SINCE CELL INSTALLATION
21
23
25
10"
-------
10
~4
LU
LU
DC
CT)
i io-8
o
OL .
io
-12
MUNICIPAL SOLID WASTE - CELL 4
BATTERY PRODUCTION WASTE AND
MUNICIPAL WASTE - CELL10
I
I
I
3 5 7 9 11 13 15 17 19 21
TIME IN MONTHS SINCE TEST CELL INSTALLATION
23
25
LU
- MUNICIPAL SOLID WASTE - CELL 4
CHLORINE PRODUCTION BRINE SLUDGE
AND MUNICIPAL WASTE -CELL14
I
I
I
I
I
3 5 7 9 11 13 15 17 19 21
TIME IN MONTHS SINCE TEST CELL INSTALLATION
23 25
FIGURE 3. TOTAL KJELDAHL NITROGEN REMOVED
THROUGHLEACHING
48
-------
1-11
tu
(-
CO
g
_i
O
01
O
SOLID WASTE - CELL 4
CHLORINE PRODUCTION BRINE SLUDGE
AND MUNICIPAL WASTE- CELL14
3 5 7 9 11 13 15 17 19
TIT, 1 IN MONTHS SCINCE TEST CELL INSTALLATION
21
10"
LU
-9
10
_J
o
O>
| 10-7
O
o>
10
-5
MUNICIPAL SOLID WASTE - CELL 4
INORGANIC PIGMENT WASTE AND
MUNICIPAL WASTE - CELL 13
3 5 7 9 11 13 15 17 19
TIME IN MONTHS SCINCE TEST CELL INSTALLATION
21
FIGURE 4. CHROMIUM REMOVED THROUGH
LEACHING
49
-------
LU
t-
o
o
U5
O)
JO
a
01
MUNICIPAL SOLID WASTE - CELL 4
ELECTROPLATING WASTE AND
MUNICIPAL WASTE - CELL 12
J_
_L
_L
J_
3 5 7 9 11 13 15 17 19
TIME IN MONTHS SINCE TEST CELL INSTALLATION
21
LU
V>
a
_i
o
en
Jt
a
Ui
10
-6 _
10-8
10
-10 _
10
-12
MUNICIPAL SOLID WASTE - CELL 4
-BATTERY PRODUCTION WASTE AND
MUNICIPAL WASTE - CELL10
3 5 7 9 11 13 15 17 19
TIME IN MONTHS SINCE TEST CELL INSTALLATION
21
FIGURE 5. LEAD REMOVED THROUGH LEACHING
50
-------
10-* r
LU
t-
10
$
Q
10
-6
S 10-8
o>
.*
N
O)
10
-10
10
-12
MUNICIPAL SOLID WASTE-CELL 4
— REFINERY WASTE AND MUNICIPAL
WASTE-CELL9
3 5 7 9 11 13 15 17 19
TIME IN MONTHS SINCE TEST CELL INSTALLATION
21
10-* r
MUNICIPAL SOLID WASTE-CELL 4
-CHLORINE PRODUCTION BRINE SLUDGE
AND MUNICIPAL WASTE- CELL14
3 5 7 9 11 13 15 17 19
TIME IN MONTHS SINCE TEST CELL INSTALLATION
FIGURE 6. ZINC REMOVED THROUGH LEACHING
-------
to cell on a time basis. Para-
meters were selected which repre-
sented a variety of possible pollu-
tants, such as demand parameters,
nutrient parameters, organic and
inorganic parameters.
Excellent correlation was ob-
tained for the majority of the test
cells irrespective of the treatment
applied for total organic carbon,
chemical oxygen demand, total
Kjeldahl nitrogen, dissolved solids
and total solids. This is not to
say that the total amount of a
particular parameter leached from
the cells does not vary. It is
simply an indication that the shape
of the concentration/time curves for
these cells are very similar. In
most cases the cells correlate with
each other for the parameters
mentioned at a 99% confidence limit.
As previously discussed the re-
finery waste/municipal solid waste
test cell (cell 9) is generating a
leachate whose constituents are
present in very low concentrations.
It also has shown extremely poor
correlation with all other test
cells for all parameters. This
means that either degradation is
occurring and the parameter concen-
trations are being diluted by infil-
trating water, or that the degrada-
tion of the waste material is very
slow due to toxic effects exerted on
the microorganisms by some constit-
uent of the industrial waste
material.
Correlations for the metallic
ions vary considerably depending
upon the treatment under evaluation.
All municipal solid waste only test
cells correlate well with each
other for metallic ions and hardness.
The test cells containing industrial
wastes admixed with municipal solid
waste vary considerably depending
upon the metallic ion being dis-
cussed. In general, it appears that
variation in the correlation
coefficients for the metallic ion
is dependent once again upon the
concentration of that ion present
within the industrial waste itself.
One very positive aspect of
the correlation study was that the
replicate test cells correlated
within 99% confidence limit for
every parameter evaluated. This is
indicative that the replicate test
cells are generating similar physi-
cal and analytical results. This
is extremely important since the
variability of the replicate test
cells relates directly to the
ability to determine variation
among all other treatments being
evaluated.
GAS QUANTITY AND COMPOSITION
Studies have been completed to
determine if gas stratification by
molecular weight differences occurs
within the landfill environment.
No such stratification has been
seen.
Gas production rates for the
solid waste only test cells have
averaged between 40 and 50 liters
per day, or approximately, 13 to 15
milliliters of gas per kilogram of
refuse. It has been estimated^
that each kilogram of solid waste
during decomposition is capable of
producing 1.22 cubic feet of carbon
dioxide and 1.77 cubic feet of
methane for a total of 2.99 cubic
feet per kilogram of solid waste.
It is felt that conversion of
between 25 to 75% of the solid
waste to gas may occur within a
landfill system . Therefore, the
total gas production from a kilo-
gram of solid waste is estimated to
be within the range of 0.77 to 2.24
cubic feet per kilogram of solid
waste decomposed. If we assume the
estimated life of a landfill to be
ten years, theoretical gas produc-
tion rates for these test cells
can be calculated. Theoretical gas
production rates for the test cells
being evaluated are shown in Table
3. The test cells containing
municipal solid waste only approach
the maximum gas production that can
be theoretically achieved. The
test cell containing municipal
solid waste admixed with an indus-
trial waste, however, is slightly
below the minimum gas production
that would be expected under these
52
-------
TABLE 3
THEORETICAL AND ACTUAL GAS PRODUCTION RATES
CELL
16
17
*18
*19
CONTENT
Solid Waste
Only
Solid Waste
and Indus-
trial Waste
Solid Waste
Only
Solid Waste
Only
AMOUNT
SOLID
WASTE (Kg)
2996
2998
3000
3012
THEORETICAL ACTUAL
GAS PRODUCTION GAS PRODUCTION
Min(ft3) Max(ft3) ft3
2307
2308
2310
2319
6711
6715
6720
6747
4134
2084
6300
6024
*These test cells were loaded at a later date and are in the non-
methanogenic phase of decomposition during which time large quantities
of carbon dioxide are produced. This accounts for the higher amount of
gas production.
53
-------
conditions. We can, therefore,
assume that some adverse effect is
being exerted by the industrial
waste present within this test
cell.
CONCLUSIONS
1. Existing analytical methods are
available for the accurate and
precise determination of chemi-
cal parameters within landfill
leachates. Replicate analyses
and standard addition samples
should be analyzed also to
insure validity of the results.
2. Gas permeation of polymeric and
synthetic materials occurs in
substantial quantities. This
should be considered when
evaluating liner materials for
actual land disposal sites.
3. High moisture content industrial
residuals with municipal solid
waste appears to have no effect
on organic, nutrient and demand
parameters.
4. The addition of the evaluated
industrial residuals with
municipal solid waste appears to
have no effect on organic,
nutrient and demand parameters.
5. The co-disposal of industrial
residuals with municipal solid
waste may have an effect on the
metallic ion concentration
within the leachate. This is
highly dependent upon the
chemical composition of the
industrial waste itself.
6. Gas stratification by molecular
weight does not appear to
occur within a landfill environ-
ment.
7. Certain industrial waste resid-
uals may have a significant
effect upon gas production rates
within a landfill environment.
The theoretical gas production
rate of between 1.0 and 2.2
Cubic feet per kilogram of solid
waste decomposed appears to be
valid.
ACKNOWLEDGEMENTS
This work was supported by the
U. S. Environmental Protection
Agency (Contract No. 68-03-2120)
under the direction of the Municipal
Environmental Research Laboratory
in Cincinnati, Ohio. The Project
Officer for this contract was
Mr. Dirk Brunner.
REFERENCES
1. Chian, E. S. K. and F. B. DeWalle
"Compilation of Methodology Used
For Meauring Pollution Parameters
of Sanitary Landfill Leachate".
EPA-600/3-75-011, U. S.
Environmental Protection Agency,
Cincinnati, Ohio (October, 1975).
2. Cameron, R. D. and E. C. McDonald
"Procedures for the Analysis of
Landfill Leachate". EPS-4-EC-75-
2, Environment Canada, Solid
Waste Management Report,
(October 1975).
3. Streng, D. R., "The Effects of
The Disposal of Industrial Water
Within a Sanitary Landfill
Environment", EPA-600/9-76-015,
U. S. Environmental Protection
Agency, Cincinnati, Ohio
(July 1976).
4. Streng, D. R., "Effects of
Industrial Sludges on Landfill
Leachates and Gas Production".
National Conference on Disposal
of Residues on Land, St. Louis,
Missouri (September 1976).
5. Anderson, D. R. and J. P.
Callinan, "Gas Generation and
Movement in Landfills".
6. Pacey, J. G. and R. S. Altmann,
"Methane Gas in Landfills:
Liability or Asset", National
Solid Waste Management
Association Conference, Atlanta,
Georgia, (1975).
54
-------
INFLUENCE OF MUNICIPAL SOLID WASTE PROCESSING
ON GAS AND LEACHATE GENERATION
By:
Melvin C. Eifert, P.E.
Joseph T. Swartzbaugh, Ph.D.
SYSTEMS TECHNOLOGY CORPORATION
Xenia, Ohio
ABSTRACT
The purpose of the experiment
is to evaluate the effect of differ-
ing preplacement processing tech-
niques on the production of gas
and leachate by landfilled municipal
solid waste. Five in-ground, con-
crete test lysimeters, 7 ft. x
11 ft. x 12 ft., were prepared and
filled with processed refuse and
then sealed. The types of process-
ed refuse studied are: shredded
unbaled refuse (Cell 4}; shredded
baled refuse (Cell 1); baled whole
refuse (Cell 2); and baled whole
refuse placed in a "saturated"
condition (Cell 3). One lysimeter
contains unprocessed whole refuse
as a control (Cell 5).
This paper presents the results
of the first two years of observing
the completed lysimeters. Leachate
volume and composition and gas com-
position histories are discussed.
Gas volume data is incomplete due
to periodic failure of the gas seals
on the lysimeters. Correlation co-
efficients were calculated for the
pollutant production data to compare
the relative effects of the five
studied processing options. Such
comparison shows that the time
histories of pollutant production
are similar in nearly every case.
Differences in magnitude of total
pollutant are too small to conclude
that the cumulative emissions do not
belong to the same set.
INTRODUCTION
The intent of the present pro-
gram was to determine the effect of
different pre-landfilling process-
ing techniques on quantity and
composition of gas and leachate
produced from municipal solid waste
in a landfill environment. The
processing options of interest were
shredding, shredding and baling,
and baling alone. At the same time,
it was of interest to determine the
effect of a highly moist (saturated)
environment on gas and leachate
production and to compare all treat-
ments to the emissions from un-
processed waste.
To accomplish this goal, a
facility consisting of five identi-
cal test lysimeters and an instru-
mentation cell was designed. Each
test lysimeters were designed to
hold approximately 10,000 kilograms
of municipal solid waste when com-
pleted. The cells were constructed
inground and, except for the
"saturated" test cell, were sub-
jected to a moisture regimen simu-
lating the rainfall pattern of the
Midwestern United States. In order
to compare the processing options,
55
-------
Cell 1 was loaded with baled
shredded refuse; Cell 2 with baled,
whole refuse; Cell 4 with unbaled,
shredded refuse; and Cell 3 with
baled, whole refuse subjected to a
high moisture regimen. Unprocessed
whole refuse was loaded into Cell 5
as a control for comparison pur-
poses. These cells were construct-
ed, loaded with municipal solid
waste, and sealed. They have been
continuously monitored since
January, 1975.
FACILITY DESCRIPTION
The test cells were constructed
of reinforced concrete and have in-
side dimensions of 2.1m by 3.4m by
3.7m. The walls are 20cm thick
reinforced concrete, and there is a
separation of l.lm between each
cell. Instrumentation access to
the interior of the cells was
provided by casting sleeves into the
front cell wall and then installing
bulkhead fittings.
A data collection cell is
located in front of the middle test
cell and is designed to contain the
terminals and collection ports for
all gas, leachate, temperature, and
moisture monitoring equipment.
The interior of the test cells
was intended to simulate a typical
sanitary landfill, while still
permitting the required sampling
and monitoring. Therefore, each
test cell contains a 14cm base of
non-reactive silica gravel, three
layers of baled refuse or 2.7m of
compacted refuse, covered by 30cm
of compacted clay with 30cm of pea
gravel above that. Each test cell
also has 15cm of free-board above
the pea gravel. A water injection
rake is buried in the pea gravel
in an attempt to distribute the
water uniformly over the top of the
cell so that moisture might seep
gradually into the waste in a uni-
form manner, similar to that which
would occur when rain falls on a
landfill.
The cells are instrumented for
temperature and moisture measure-
ments within and have gas and
leachate collection lines emanating
from the cells. Thermocouples are
located at 24 points distributed
throughout the refuse in each cell
to determine the temperature profile
within each cell.
The moisture monitoring equip-
ment placed within the cells con-
sisted of both gypsum soil blocks
and porous cup tensiometers. Gypsum
soil blocks are merely water absorp-
tive resistors. As moisture is
absorbed, their electrical resis-
tance changes and is measured with
an ohmmeter, calibrated to directly
read moisture content. There are
nine gypsum soil blocks in each
test cell.
The porous cup tensiometer con-
sists of a porous ceramic tube fill-
ed with water. The tendency of the
water to flow through the ceramic
tube will depend upon the partial
pressure of water outside the tube.
A vacuum gage connected to the
ceramic tube allows measurement of
the water remaining with the tube,
and thus indirectly, of the moisture
outside the tube.
The floor of each test cell
slopes slightly toward the center
front where a leachate collection
line is located. These lines pass
through to the instrumentation cell,
where they are valved to permit
periodic removal of leachate
collected in the bottom of the
cells.
The original gas monitoring
system installed in the cells con-
sisted of 10 collection probes, 9
of which were located in the solid
waste and one of which was located
in the head space of each cell.
These collection lines passed
through the front wall of the test
cells and were manifolded and
valved and connected to a precision
wet test gas meter. The gas
collection and monitoring system
proved to be totally inadequate and
was modified, as will be discussed
in a later portion of this paper.
56
-------
Before loading the test cells,
all the interior surfaces were coat-
ed with coal tar epoxy to prevent
leaching of the concrete cell walls.
A cast concrete cell cover was
placed on top of the cells after
loading. Gasket material made of
vinyl tubing was installed between
the cell wall top and the cell
covers in an attempt to assure gas-
tight integrity. Figure 1 is an
isometric showing the outside of a
typical test cell used in this
study.
SOLID WASTE LOADED
All solid waste had been
planned to be obtained in the Dayton,
Ohio area, the shredding and baling
to be done in appropriate facilities
near Dayton, Ohio. A fire at the
originally proposed baling facility
precluded this, and the only baling
system available for use at the
time was one located in Cobb County,
Georgia. Fortunately, a shredder
facility was also available in
nearby DeKalb County. So, municipal
solid waste was obtained in DeKalb
County and shredded there, trans-
ported to the Cobb County baler
facility, baled and transported to
the test site at Franklin, Ohio.
Unbaled waste was obtained from
Oakwood, Ohio. Some of that waste
was shredded at the Montgomery
County, Ohio shredder facility in
the south incinerator plant prior
to transport to the test sites at
Franklin, Ohio. Samples of the
different refuses were categorized
using hand-sorting techniques to
determine the composition of the
loaded wastes. Results of this
categorization are shown in Table 1.
The baled refuse was loaded in-
to the cells and backfilled with
clay in an attempt to retain the
high compaction density.in the bales
(850 kilograms per cubic meter).
Nonbaled refuse was placed and com-
pacted to 550 kilograms per cubic
meter for the shredded waste and
500 kilograms per cubic meter for
the unshredded waste. All waste was
covered with clay, which was then
compacted. Finally, all were
covered with pea gravel and sealed
with precast concrete cell covers.
The monitoring program then
officially began.
MONITORING
As indicated earlier, tempera-
ture was measured within each test
cell with an array of 24 thermo-
couples. Test cells uniformly show
a history of following the ambient
outside temperature, with the bottom
portion of the cell being warmer in
winter and cooler in summer than the
top. The vertical temperature
differences were in the range of 5°C
to 10°C. The tops of the test cells
experienced a seasonal temperature
variation in the range of 40°C,
while the bottoms of the test cells
experienced only an 18°C seasonal
temperature variation. Comparing
these findings to the ambient ground
temperature indicates that the test
cell contents are a few degrees
cooler than the ground in winter and
a few degrees warmer than the ground
temperature in summer. This
indicates that the test cell con-
struction materials are better heat
conductors than the ground itself.
There were 11 moisture probes
in each test cell. There has been
a fairly high failure rate (about
40 percent) of the gypsum block
moisture probes. The moisture
probes indicated some initial short-
circuiting, but now they indicate
uniform moisture throughout the test
cells. Gypsum block probes are
presently reading 100 percent
saturation within the test cells.
This is not borne out by the mois-
ture retained curves presented as
Figures 2 through 5. This dis-
crepancy may be due to the fact that
moisture probes were calibrated for
water while the leachate within the
test cells has a significantly
different conductivity than the
57
-------
GAS LINEfHEAD SPACE)
THERMOCOUPLE
I CONDUIT
WATER ADDITION LINE
SAMPLE GAS
LINES
LEACHATE
DRAIN
FIGURE 1. CONFIGURATION OF TEST CELLS
58
-------
CATEGORIES
in
-------
CELL 1 BALED SHREDDED WASTE
1000 -
O 80°
LU
Q
< 600
O
N
I 400
200
400
j? 300
Q
HI
Z
200
LU
oc
O
cv
X
100
7,0©
O
O
O
O
O
ooo
O
O
I
12
TIME
12
FIGURE 2. MOISTURE DATA FOR CELL1
60
-------
1000
C. 800
Q
LU
Q 600
Q
400
200
0
CELL 2 BALED WHOLE WASTE
1
400
300
j=
o
LJJ
H
LU
IT
O
CM
I
200
100
0%
0
Q00
0 ©o
0
000
0
0© -
000
O
12
TIME
12
FIGURE 3. MOISTURE DATA FOR CELL 2
61
-------
CELL4 NONBALED SHREDDED WASTE
O
01
Q
O
<
O
CM
X
1000
800
600
400
200
500
400
O
0
O
Q
UJ
Z
300
O
O O
O
o
LLI
01
CM
200
100
O
o
O
O
12
TIME
12
FIGURE 4. MOISTURE DATA FOR CELL4
62
-------
CELL 5 IMONBALED WHOLE WASTE
1000 -
— 800
r*
o
£ 600
a
O 400
CM
I
200
0
500
O
ooo
O U O
O
O
O
400
O
O
O)
JsC
2 30°
2
200
100
O O O O
O
o
o
o
6 12 6
TIME
FIGURE 5. MOISTURE DATA FOR CELL 5
12
63
-------
water. This would affect the
apparent electrical resistance of
the gypsum block probes. It is
sufficient for our purposes now,
however, to know that the moisture
levels are consistent throughout
each test cell.
Total moisture retained within
the cell is inferred directly from
the volume of water added minus the
volume of leachate removed. Since
the test cells are enclosed, tran-
spiration and runoff do not enter
into the calculation. The moisture
retained plots in Figures 2 through
5 indicate that the rate of change
of retention is decreasing but that
field capacity has not yet been
reached in any case.
Gas was to be collected by nine
perforated plastic pipes placed in
the test cells within the body of
the solid waste, and one perforated
pipe located in the head space of
each test cell. These perforated
pipes were connected to manifolds
which passed through the walls of
the test cell and led to the
instrumentation cell. They were
valved so that individual levels
within the test cells could be
sampled separately. Samples were
to be drawn off into glass sample
tubes for gas chromatographic
analysis. The analysis was intended
to determine the 02, CO2, CHU, and
H2 contents of the product gas. Gas
volume was to be determined by com-
bining all the gas loads from an
individual test cell into one line,
which vents through a precision
wet test meter. Further details on
the gas collection system and its
related problems are discussed in
the following section.
Leachate was collected from
the bottom of each test cell by
lines which led to the instrumenta-
tion cell. The pH and conductivity
of the leachates were measured and
the individual leachate samples
collected were measured for chemical
oxygen demand, total organic carbon,
alkalinity, hardness, total phos-
phorous, Kjeldahl nitrogen, total
solids, dissolved solids, chlorides,
and for the following metals: iron,
copper, zinc, cadmium, chrome, lead,
and nickel. Leachate samples were
also analyzed for total coliform
count and fecal strep count. Results
of the leachate study are presented
in following sections of this report.
GAS MONITORING
One of the principal goals of
the study was to determine volume
and composition of gas generated
by solid waste in these landfill
simulators. Considerable effort
was expended throughout the study
in an attempt to obtain valid and
meaningful gas data. Unfortunately,
no reliable gas data has been
generated by the study. Problems
encountered were several, and they
will be presented here so that
others may benefit by our experi-
ences in attempting to measure gas
produced in lysimeters.
First, it should be noted the
wet test gas meters employed were
not adequate for directly measuring
the small volumes of gas produced
in the early stages of a landfill
lysimeter's life. When this was
realized, a collection system
employing impermeable gas bags for
each test cell was devised. The
gas produced was to be collected
and once daily would be drawn off
through the wet test meter by a
vacuum pump. This technique is
basically sound and has been used
successfully by SYSTECH in labora-
tory studies of gas produced by
anaerobic digesters.
By referring to Figure 1, the
reader can see there are several
points at which the structural
integrity of the landfill test cell
is breached. The 10 gas collection
lines pass through the front wall
individually; the water addition
line passes through the front wall;
the instrumentation access line
passes through the front wall; and,
finally, the leachate collection
line passes through the front wall.
64
-------
Each of these exit points was
originally sleeved and gasketed with
RTV and was thought to be gas-tight
at the time.
The cell cover is a precast
concrete slab. Both it and the cell
wall tops are sufficiently nonuni-
form that the vinyl tubing used for
gasketing was insufficient. Finally,
the manhole in each of the cell
covers was insufficiently gasketed.
Each of these points is a potential
gas leak and in fact and in practice,
nearly every one of these points
proved to be a source of gas leaks.
Attempts were made to seal the cell
from the outside when these leaks
were discovered and the inadequacies
of the design were understood.
It was discovered at that time
that several purported sealant and
adhesive materials were neither
sealants nor adhesive. An extensive
study was then undertaken by SYSTECH
to determine the relative perme-
ability of various candidate
materials for use in a gas collec-
tion system. In this study, it was
discovered that most plastic and
rubber materials were permeable to
methane and carbon dioxide, and
these included several materials
which manufacturers assured us were
impermeable. The only adhesive
sealant material which we have found
to be impermeable to these gases is
a 3M metal sealant.
It is our recommendation that
any gas collection system used in
landfill lysimeters be constructed
with metal gas distribution lines,
and that the gases be collected in
aluminized plastic or Tedlar gas
bags. Separable surfaces should be
smooth and preferably should have
an incised notch to ensure positive
placement of any gasket material.
Surfaces to be gasketed should be
drawn together, preferably with a
nut and bolt type arrangement. And
finally, it is questionable whether
concrete is a suitable material for
landfill lysimeters when gas data
is of interest. As a large
lysimeter settles in the earth, the
concrete could crack and thus de-
stroy any gas-tight integrity which
it may have had at the beginning.
Large steel containers could be
continuously welded for greater
assurance of gas-tight integrity.
In spite of extensive efforts
to seal and leak test the lysimeters
in the ground at Franklin, we have
come to the conclusion now that this
is impossible. Effective sealing
was accomplished for short periods
throughout the study and some gas
volume data was generated during
those periods. However, the possi-
bility of intermittent failures of
gas-tight integrity must lead us to
conclude that none of our gas data
is reliable. We must include in
this disclaimer the measured com-
position data since all test cells
show some oxygen content. The
presence of oxygen in the test cells
two years after their initiation
would be highly unlikely if the test
cells were truly sealed.
LEACHATE DATA
The most significant results of
the present study arise from the
conclusions we are able to draw from
the leachate data. Leachate samples
were withdrawn from each test cell
monthly. The volume was recorded
and the various parameters mentioned
previously were measured. In order
to compare the effect of the various
processing modes studied on the
leachate produced, it was decided to
do a cell-to-cell comparison of the
time histories of the parameters
measured. A correlation analysis
comparing the results of each cell
with every other cell was performed
using commercially available comput-
er programs. Correlation analysis
is a statistical technique for
determining the degree of associa-
tion between variables. It entails
calculating a correlation co-
efficient which is defined as co-
variance of the two variables
divided by square root of the pro-
duct of the variances of the
individual variables. If the two
65
-------
variables are highly related, the
correlation coefficient will be
close to 1.0. If they are not well
related, the correlation coefficient
will be close to zero. Depending
upon the number of times the two
variables of interest are measured,
the value of the correlation coef-
ficent needed to be confident to a
predetermined degree (95 percent,
99 percent, etc.) that the variables
are related can be determined. It
was decided in the present study to
use a 95 percent confidence level as
a rejection criterion. Correlation
coefficients were then calculated
for the leachate data using a pack-
aged computer program, "BMD02."
The results of this analysis
were that in nearly every case, time
histories of the pollutant concen-
trations showed better than 95 per-
cent confidence that the data
correlated from cell-to-cell. Table
2 shows the exceptions to this, i.e.,
those cell pairs for particular
parameters which do not show 95 per-
cent probable correlation. What
this means is that while the magni-
tudes of the pollutant emitted from
individual cells may differ, the
time histories of these emissions
were very similar.
In order to determine the total
pollutant emitted from the indi-
vidual cells, cumulative values of
the mass flows of the individual
parameters were calculated and
plotted (Figures 6-9}. The shape of
the curves in each case is very
similar, and would appear to be
described by a power curve where the
total pollutant is a function of
time to the power 3 or greater. As
a final check, to compare the indi-
vidual cells, the total mass flow of
each pollutant leached per unit mass
of solid waste in the individual
cells was calculated for total solids,
dissolved solids, chemical oxygen
demand, total organic carbon, hard-
ness, iron, copper, zince, cadmium,
chromium, lead and nickel (Table 3).
Results tend to show quite similar
results for each cell with Cell 5
the non-baled, non-processed waste,
generally showing the lowest total
pollutant mass leached to date. Even
so, it does not appear to be signif-
icantly different from the leachate
of the other cells.
The conclusion we draw at this
time is that no significant differ-
ence can be seen in the leachate
emanating from the test lysimeters
no matter what processing technique
is used. Two years of study is too
short to determine that there is no
difference in the leachate from
baled or shredded or whole waste
landfills, but there would appear
to be no significant difference in
the early stages of landfill life.
66
-------
TABLE 2. COMPARISON OF TIME HISTORIES OF
POLLUTANT CONCENTRATONS FROM EACH CELL
All parameters show better than 95% correlation when compared from cell to
cell except as noted below.
Parameter
PH
Conductivity
COD
TOG
Alkalinity
Hardness
Phosphorous
Kjeldahl Nitrogen
Total Solids
Dissolved Solids
Chloride
Iron
Copper
Zinc
Cadmium
Chronium
Lead
Nickel
Total Coliform
Fecal Strep
Cell Pairs Which Don't Correlate
1-2, 1-3, 2-4, 2-5, 3-4, 3-5
1-3
1-4
3-5
1-3, 1-5, 2-3, 2-5
1-2, 1-3, 1-4, 1-5
1-3, 1-4, 2-3, 2-4, 3-5
1-4, 1-5, 1-4, 2-5, 3-5, 4-5
Only 4-5 correlate, no others do
Only 1-4, 2-3, 4-5 correlate, no
others do
67
-------
MASS FLOW
TOTAL SOLIDS
140
I
CELL 1 A 0
CELL 2 D
CELL 3 V
120 H CELL 4 O O
CELL 5
O
^ 100 U O
o
1 80 f- O
D
U
W
QQQQ;O
40
A
A ^
201- A
A 0.00°
12 6 12
TIME
FIGURE 6. MASS FLOW TOTAL SOLIDS
68
-------
MASS FLOW
TOC
60
I
CELL1 A
60 h CELL2Q 00
CELL 3V Q
CELL 4 O
CELL 5 O O V
o> \7
^40 "V
LU
| „ o
D
O
O
o
o
20 h a
a
v v vv
12 6 12
TIME
FIGURE 7. MASS FLOW TOC
69
-------
TOTAL IRON
CELL 1 A W
CELL 2 n
CELL 3V
CELL 4 O Q
CELL 5 <()> V
S DA
^^.
O
cc
H it. a
< T A
V
12 6 12
TIME
FIGURE 8. MASS FLOW - IRON
70
-------
TOTAL COPPER
o>
E
04
? 4
a.
a.
O
O
LU
O
CELL 1 A
CELL 2 D
CELL 3 V
CELL 4 O
CELL 5
A . 0
Q O o
aa O o
A 0°
FIGURE 9. MASS FLOW -COPPER
71
-------
TABLE 3. TOTAL POLLUTANT MASS LEACHED TO DECEMBER 1976
(Mass of Pollutant Per Unit Mass of Solid Waste)
PARAMETER
COD
TOG
HARDNESS
TOTAL SOLIDS
DISSOLVED
SOLIDS
IRON
COPPER
ZINC
CADMIUM
CHROMIUM
LEAD
NICKEL
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
(MG/KG)
CELL 1
5,783
2,438
1,880
5,229
1,501
125
.037
4.58
.017
.092
.124
.24
CELL 2
7,161
2,731
1,593
4,954
1,016
157
.032
6.59
.016
.103
.095
.29
CELL 3
10,900
3,869
2,023
7,218
3,048
134
.039
3.18
.020
.110
.057
.37
CELL 4
15,570
4,748
2,919
12,230
1,729
188
.020
2.12
.022
.093
.147
.62
CELL 5
7,527
1,900
1,245
5,142
631
31
.026
4.12
.015
.043
.056
.24
72
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EFFECT OF MOISTURE REGIME AND OTHER FACTORS ON
MUNICIPAL SOLID WASTE STABILIZATION
E. S. K. Chian.V. B. DeWalle? E. Hammerberg1
Department of Civil Engineering, University of Illinois, Urbana, Illinois
2
Department of Civil Engineering, Stanford University, Stanford, California
ABSTRACT
The present study measured the rate of solid waste stabilization under anaerobic
conditions as reflected by the rate of gas production. The major gases produced by the
solid waste were C02, Hg and City. The effect of different environmental variables on the
rate of solid waste stabilization was measured. Higher rates of stabilization resulted
from higher moisture contents, incre'asinq temperatures,decreasing solid waste size and
decreasing density. The H2 was primarily detected in the containers with the lowest
moisture content, while CH4 was found in the container with the unshredded refuse.
INTRODUCTION
Placement of solid waste in landfills
is the most common method of ultimate
disposal of the refuse. Some impairment
of the environment, however, can occur by
the release of explosive gases resulting
from decomposing- refuse. On the other
hand, these gases, primarily methane(CH4)
and hydrogen (H2) can be recovered from
the landfill and converted to useful
energy by combustion. If all the methane
from solid waste maintained under optimum
digestion conditions could be recovered }
up to 11% of U.S. natural gas demand could
be satisfied (1). The formation of gaseous
products parallels the decomposition of
the solid waste. Since ultimate use of
a landfill requires a sufficient degree of
biological and physical stabilization,
knowledge of the relation between the gas
formation and solid wastes stabilization
may allow the former to be used as a tool
for landfill monitoring. It was therefore
the purpose of the present study to measure
the amount and composition of gases gener-
ated during anaerobic decomposition of
solid waste in a simulated landfill, and
to determine the effect of environmental
conditions, such as temperature moisture
content, size of the solid wastes and
density on the quantity and quality of the
product gas.
ANAEROBIC DEGRADATION OF SOLID WASTE
Formation of gases from solid waste
only occurs under anaerobic conditions; the
anaerobic degradation of carbohydrates, for
example, does not have a net production of
gas:
6C02+6H20
(1)
When fatty acids such as stearic acid are
degraded aerobically there is even a net
reduction (31% in the case of stearic acid)
in the gas phase:
C18H3602+26Q2
18C02+18H20
(2)
Under anaerobic conditions, however, the
gas production is substantial in the acid
fermentation stage in which the carbo-
hydrates are converted to acetic and
butyric acid and to a lesser extent into
propionic acid:
C6H12°6
C6H12°6
(3)
(4)
73
-------
whereas in the methane fermentation stage
in which the free volatile fatty acids are
converted into methane and carbon dioxide:
C6H12°6 "*" 3C02f*3CH4* ^5^
The overall reaction can be described as:
+(y)NH3+(Z)H2S
(6)
Most sanitary landfills are known to pro-
duce C02 and CH4, indicating that anaerobic
conditions are maintained in the solid
wastes.
The hydrolysis of cellulosic materials,
the major component of the organic fraction
in solid waste, occurs through an
enzymatic step in which a C] enzyme con-
verts the crystalline cellulose to an
amorphous hydrated polyanhydroglucose,
which is further hydro! ized by Cx enzymes
to cellobiose which can be taken up by
bacterial cells and converted to glucose
by B-glucosidase. Cowling and Brown (2)
indicated that environmental factors,
especially moisture content, determine
the rate of the overall hydrolysis reaction,
since the moisture helps to swell the
capillaries of the fibers0beyond their
diameter, as small as 25 A for pulp, to
allow penetration of cellulose enzymes
with equivalent sizes of 30 x 170 A.
Stone et al_. (3) therefore noted that the
cellulose hydrolysis rate was proportional
to the surface area accessible to a
molecule of 40 A in diameter. Thus
increasing the surface area by milling
of the solid waste will enhance the cell-
ulose hydrolysis. Using the digestion
efficiency of sewage sludge as a reference,
Klein (4) noted that the efficiency of
garbage digestion, expressed as liters of
gas produced per kg solids destroyed,
was 90% of that of sewage sludge. The
digestion efficiency of Kraft paper was
95%, newspaper 44%, garden debris 73%,
and wood only 4% of that of sewage sludge.
The higher digestion efficiency of news-
paper pulp as compared to wood is due to
the mechanical pulping process which
increases the surface area from 1 m2/g to
40 m2/g in pulp. The presence of lignin
is thought to decrease the accessible
cellulose surface area. The digestibility
of pulp therefore increases from 44? to
95% after chemical removal of the
majority of the lignin by sulfite pulping.
Other environmental factors such as
pH, nutrient conditions and metal content,
exert significant effects on the rate of
cellulose digestion. Dubos (5), for
example, noted an optimum pH of 6.5 to 8.2
for cellulose decomposing microorganisms.
Heukelekian (6) studied the decomposition
of cellulose in limed and unlimed anaero-
bic digesters. In the latter unit the pH
decreased to 5.2 after 7 days corresponding
to a 30% cellulose removal. In the limed
unit the pH stabilized at 7.4 resulting in
a 73% cellulose removal, indicating that
higher pH values enhance the cellulose
hydrolysis. Hazeltine (7) investigated
the digestion of garbage in anaerobic
digesters and indicated that digestion of
garbage alone produces acidic conditions,
but found that ratios of 1.5 to 3 parts
garbage to 1 part of sludge resulted in
sufficiently high pH values. Golueke and
McGauhey (8) noted that the pH decreased
below 6.8 when the ratio of garbage
(vegetable trimmings) to sewage sludge
increased beyond 3:1 in digesters
maintained at a 30-day detention time.
Gradual acclimation to garbage, however,
allowed a successful digestion at a 100%
garbage level without significant pH
decreases.
Maki (9) studied the hydrolysis of
cellulose in an aerobic digester seeded
with anaerobic digester supernatant and
noted that the primary products were H2
and C02 gas and acetic acid (41% on a
molar base), ethanol (39%), formic acid
(15%) and lactic acid (6%). Alcohols
can further be oxidized to fatty acids with
C02 acting as the hydrogen acceptor to form
methane. Mixed anaerobic bacterial strains
generally resulted in higher hydrolysis
rates of up to 0.07% per day. Pure
cultures often experiencing hydrolysis
rates of only 0,03% per day. The higher
rates of the mixed cultures were due to
the more rapid removal of inhibiting
metabolites. Hill (10) investigated the
digestion of paper pulp mixed with differ-
ent amounts of sewage sludge so as to
vary the C:N ratio, and noted that optimum
digestion occurred at C:N ratios of 20:1
to 53:1. Heavy metals can cause inhibition
of the cellulose decomposition, and Uesaka
(11) measured inhibiting concentrations of
500 mg/1 Fe, 50 mg/1 Zn, and 5 mg/1 Cu.
74
-------
Several investigators noted that the
cellulose hydrolysis rate is often the
overall reaction rate-controlling factor,
and conditions should be optimized with
respect to this step. Based on the rates
of removal of the metabolites, Maki (9),
for example, concluded that this step was
not rate-limiting and that the preceding
cellulose hydrolysis rate actually deter-
mined the overall reaction rate. Chan and
Pearson (12) investigated the anaerobic
digestion of kraft paper pulp powder at
detention times of 10, 15, 20 and 30 days
and noted that about half of the carbon
input was converted to gas. They further
noted, similarly to Maki (9), that the
hydrolysis of cellulose to cellobiose was
the overall rate-limiting step.
Pfeffer (13) calculated a maximum
theoretical gas production of 0.55 t/g
volatile solids (VS) added but actually
measured a rate of 0.2 g t/g VS added, or
0.24 t/g solids added, at 35°C, and a
30-day detention time, indicating that only
half of the volatile solids in refuse are
digestible. Cooney and Wise (14) measured
a gas production of as high as 0.47 t/g VS
added or 0.27 t/g solids in digesters
maintained at a 30-day detention time at
39°C.
ANAEROBIC PROCESSES IN LANDFILLS
In actual landfills similar anaerobic
decomposition processes will occur. When
the oxygen initially present in the gas
phase within the solid waste decreases to
low levels, anaerobic processes gradually
replace aerobic processes. This is also
reflected by the increase of the C0£
content above 20%. Only 20% can ever be
found under aerobic conditions, as only
that much C02 can be found from the con-
sumed 02 present at an initial concentra-
tion of 20%. Anaerobic conditions
generally restrict the activity of the
aerobic thermophilic organisms and enhance
the mesophilic anaerobes. This shift is
generally accompanied by a decrease of the
landfill temperature. Eliassen (15), for
example, noted that aerobic conditions pre-
vail near the surface of landfills result-
ing in relatively high temperatures
(71°C at 0.9 m depth), while in deeper
layers anaerobic conditions and lower
temperatures prevail (40°C at 3.3 m).
Anaerobic processes are generally occurring
at a lower rate than aerobic processes and
landfill stabilization is therefore more
rapid under aerobic conditions. The
substantially lower moisture contents,
in landfills as compared to anaerobic
digestion studies discussed earlier will
result in far lower gas production rates.
Carpenter and Setter (16), for example,
noted that in a dry fill the gas phase
consisted of 34% C0£ and 7% CH4, while in
a moist landfill the concentrations were
as high as 35% and 65%, respectively.
Merz aad Stone (17) similarly noted an
increase in the methane.content with
increasing moisture of the solid waste at
the Spadra test sites. The existence of
anaerobic processes was further confirmed
by Bishop ert al_. (18) who measured an
excess gas pressure in landfill which
forced the gases out through the surface
cover (93-95%) or through the bottom and
side walls of the landfill (5-7%). They
further calculated a maximum gas produc-
tion rate of 0.128 £/kg.day during the
initial COg bloom. An increase in moisture
content as a result of rainfall entering
the fill caused a second C02 bloom and a
rise in the gas production to 0.099 -£/kg.
day. During the three-year observation
period the methane content increased to
about 11%. Rovers and Farquhar (19)
noted that excessive infiltration of melt
water decreased the methane content in the
gas phase from 19% to 4%, while the C02
content increased and pH of the leachate
decreased, indicating that the acid
hydrolysis under such conditions is
occurring at a faster rate than the
methane fermentation. When stable condi-
tions exist in the landfill the opposite
is observed. Merz and Stone (20), for
example, noted that the instantaneous
application of 11 to 24 cm of water caused
a significant increase in the methane
content of the gas phase in favor of the
test cells at the Spadra landfill.
Very few studies measured the quantity
and composition of gases produced when
solid waste was placed under anaerobic
conditions in an enclosure. This approach
is by far the most accurate way to measure
the gas quantity, and was successfully
used by Merz (21), Merz and Stone (17),
Ramaswamy (22), Rovers and Farquhar (19).
Jackson (23) and McCabe (24) are using a
similar technique with industrial waste
and baled solid waste; the present study
was funded by the U.S. Environmental
Protection Agency parallel to the latter
two studies and intended to investigate
75
-------
some of the same factors that influence the
gas production generated during anaerobic
decomposition of solid waste.
MATERIALS AND METHODS
The present study employed eighteen
208 I (55 gallon) steel containers that
were filled with 55 to 80.5 kg dry weight
of solid waste, sealed and maintained at
different environmental conditions, with
subsequent measurement of the gas produc-
tion and composition. A representation of
the solid waste container is shown in
Figure 1. Each drum was lined with 10
polyethylene bags of 0.15 mm thickness.
A cushion of construction sand was placed
between the drum floor and the plastic
liner, with a gradual slope to a height of
about 8 cm at the edge of the drum to
funnel leachate towards the drain. A
15-cm layer of Class A gravel provides
collection of the leachate and screening
of the drain. A fitting was installed on
the top of the drums to allow the applica-
tion of water to the solid waste (Figure
2, Detail B), while a second fitting
allowed for collection of gases and access
for the thermocouple wires (Figure 2,
Detail A). The drain installed at the
bottom of the container allowed for collec-
tion of leachate (Figure 3, Detail D).
To Chart Recorder
Se«C
Gas Collection Device
See Detail "B
Wafer Inlet
Sprinkler
Plastic Liner
Thermocouple
Foam Pad
Sard Cushion
Plastic Liner
See Detail "0*->
DRUM CROSS SECTION
Figure 1
Cross-section of Solid Haste Container
Thermocouple Wire
Cos Collected
Lm« -\
Seokmt
Silicons Seolont
GAS OUTLET DETAIL "A"
Nolg«r* Twist-Cock
Twill-Cock Sat m
PtosJic Resin
Silico/ie Seolont
nside Surface of Fitting
Cooted w/Epoiy BOM
Poinl
To Sprinkler
WATER INLET DETAIL "B"
Figure 2
Details of Gas Outlet and Mater Inlet
Impermeable Gosket-i |-Silicone Sealant
/-Clomping Ring
Silicons Sealant
lid Watti
Plastic Liner——* "^-Drum Wall
LID SEALING DETAIL "C"
Not To Scole
Gasket
Plastic Liner
Note: Gasket Compound
Applied To All Gaskets
A .id Screw Threads
Prior To Assembly
DRAIN DETAIL "D"
Not To Scole
Figure 3
Details of Lid Sealina and Drain
76
-------
The solid waste for the study was
obtained at the City Solid Waste Reduction
Plant in Madison, Wisconsin. The solid
waste was collected by municipal employees
in wards 6, 7, 13, and 15 on Thursday
January 15, 1976. Ward 6 is located in
downtown Madison with values of homes
generally less than $10,000. Ward 7, with
old homes in the $20,000 range often
occupied by students, is also located in
downtown Madison. Wards 13 and 19 are
both in suburban areas with homes in the
$30,000 and"$50,000 range, respectively.
The solid waste is collected once a week
and is brought to the reduction plant
where it is milled by municipal employees
using a Tollemache mill, and shredded to
a nominal size of 0.7 to 2.5 cm. The
shredded solid waste was placed in 208 t
drums, compacted to a density of 150 kg/m^,
transported to the University of Illinois
and stored, covered, at temperatures
below 0°C.
The solid waste was packed into the
test containers through the use of a large
hydraulic ram ordinarily used for material
strength testing. A 500 kg force proved
adequate in the compaction of the solid
waste to a dry density of 310-436 kg/m3.
The degree of compaction was limited by the
resiliency of the solid waste and consid-
erable expansion occurred as the ram was
withdrawn. After compaction, the drums
were sealed. As the moisture content of
the milled solid waste was as low as 28%,
calculated on a dry-weight basis, water
was added to provide a more representative
baseline moisture content of 36%.
Sealing the drums adequately was a
major problem, as several sealants such as
a caulking compound, a synthetic rubber
(Miracle Seal, Revere Chemical Corp.,
Salem, Ohio), a gasket compound (Form-a-
Gasket #2, Permatex, Inc., Kansas City,
Kansas) and an aluminum-backed duct tape,
proved unsuccessful. The sealant combina-
tion that did work was a ketone based
metal (#2084, 3M Company, St. Paul,
Minnesota) and a silicone rubber sealant
(#8640, Dow-Corning, Midland, Michigan)
(Figure 3, Detail C). In sealing the
drums, the lip of the drum lid was given
a coating of the 3-M sealant and then
fitted with an impermeable gasket. The
gasket and drum rim were then coated with
the 3-M sealant and the lid was placed on
the drum and temporarily clamped in place.
The part of the gasket that remained
exposed then received an application of the
3-M sealant, forming a continuous layer of
sealant between the drum and the lid.
After this layer was cured, a process
which required 2 to 3 days, it was coated
with a layer of silicone rubber sealant.
A heavy duty bolt-type clamping ring was
then installed and tightened as much as
possible. The points where the ring con-
tacted the drum were then coated with the
silicone rubber sealant. Finally, the
fittings through which gas, water, and
thermocouple wires pass, as well as the
bottom drain, were given a coating of
silicone rubber sealant. After curing for
an additional two days, the drum was
pressurized to test for leaks. The abil-
ity of the seal to contain a pressure of
100 cm of water for 24 hours was taken as
an indication that the drum had been
adequately sealed.
The gas produced in the test cells is
collected using Mariotte flasks, consis-
ting of two bottles, one of which is placed
at a higher level than the other. As gas
is produced, it flows into the upper
bottle, displacing water from the upper
bottle into the lower one. Measuring the
change in water levels allows a determina-
tion of the volume of gas produced. Gases
were collected intermittently rather than
continuously, keeping the drums completely
sealed except for brief periods during the
gas collection. Gas was therefore collec-
ted from the drums when the initial pres-
sure exceeded 2.5 cm of water, measured
with a manometer attached to each drum.
The amount of gas produced in actively
generating containers was made with a
Precision Wet Gas Meter (Precision
Scientific, Chicago, IL). Gas volumes
were corrected for vapor pressure of water
and variation in temperature and pressure.
At low gas flow rates, the wet gas meter
was not activated, and Mariotte flasks
were used. An extensive analysis was made
of the composition of the collected gases
using a Fisher gas partitioner (Fisher
Comp., Pittsburgh, PA) model 25V using 30X
DEHS on 60/80 mesh column pack as the
first column and a Molecular Sieve 13X as
the second column. Helium is used as
carrier gas for the analysis of Og, C02,
and N2, while argon is used for the
analysis of H2-
Temperatures in the test cells were
monitored by copper constantan thermo-
couples placed in the test cells at the
77
-------
time of loading (Figure 1). All three
thermocouples were centrally located in
relation to the drum wall. To protect
against corrosion each thermocouple was
encased in heat-shrinkable tubing, which
in turn was coated with a seal (Miracle
Seal, Revere Chemical Corp., Salem, Ohio).
RESULTS AND DISCUSSION
Different factors were evaluated in
the present study, i.e., the effect of
moisture content, temperature, solid waste
size, density, and exposure to air, and a
summary of conditions and results is given
in Table 1. The largest number of con-
tainers was used to evaluate the effect of
moisture conditions on the gas production;
the necessary water was added to the solid
waste at once shortly before the sealing
of the drum lids. The effect of tempera-
ture was evaluated by placing one container
in a room with an average temperature of
26°C while all other containers were placed
at 17°C. The effect of solid waste size
was evaluated by filling two containers
with unshredded solids waste torn by hand
to approximate sizes of 12.5 cm and 25 cm,
respectively. The solid waste density was
evaluated in two containers with a density
higher and lower, respectively, than the
majority of the other containers. Three
containers were exposed to air to evaluate
the effect of air addition on the gas
composition. The results presented herein
represent the first year of data collected
under steady-state environmental condi-
tions. During the second, third, and
fourth year, transient environmental
condition will be evaluated by continuously
adding simulated rainfall to several of
the containers with the 36% moisture con-
tent. Water will be added at a rate of
25 cm/year at biweekly intervals and 50
cm/year at weekly intervals. One of the
99$ containers will be evaluated for
leachate recirculation while the other 99%
container will receive 25 cm/year with pH
adjustment.
Before the tests were started, the
solid waste composition was analyzed in
detail. A large sample size (245 kg) of
the solid waste, collected the same day as
the milled refuse was separated into the
different components, dried and weighed.
The relative composition of the dried
solid waste is given in Table 2. Compar-
ison with other data (25) showed that the
percentage of paper was less than that
generally observed. This could well be
due to the fewer students present in
Madison during the semester break at the
University of Wisconsin. More rock, ash
and dirt were also observed in the sample
which could be attributed to the cold
weather conditions during the week that
the solid waste was generated.
After loading of the solid waste in
the containers and sealing of the drums,
temperature and gas measurements were
started on March 17, 1976. The tempera-
ture in each container only rose slightly
after the sealing of the containers, as
shown in Figure 4. The difference between
the room temperature and the container
temperature varied between 2,2°C and 10°C.
The highest temperatures were observed in
the upper layers in container 17 exposed
to air, indicating that aerobic decomposi-
tion is able to raise the temperatures
considerably. The sealed containers,
with the gas line left open, were compar-
able to the completely sealed ones,
indicating that only a substantial expo-
sure to air will result in thermophilic
conditions. No consistent relation
could be detected between the average
temperature differential and moisture
content, and the size of the solid waste.
When the differential temperature was
related to the dry density, the data tend
to indicate that a higher density resulted
in a lower temperature differential. The
average temperature differential of the
warmest 50$ of the containers is 4°C
corresponding to an average dry density
of 357 kg/tn^. The average temperature
differential of the coldest 50% of the
containers is 2°C corresponding with a dry
density of 396 kg/in3.
All of the containers produced gas
and the amount produced after 300 days
varied between 5.6 t to 465 I equal to an
average daily rate of 0.29 to 20.2 mi/kg
dry weight day (Table 2). The largest
amount of gas produced represents an
amount of 6.0 £/kg dry weight (Figure 5)
which is 2.5% of the amount measured by
Pfeffer (13) in anaerobic dispersed solid
waste digesters. The results in Figure 5
clearly indicate that the cumulative gas
production in the 99% moisture containers
(numbers 6, 13, 14) increases linearly and
rapidly during the first forty days after
sealing while subsequent rates, often
linear for extended periods, can be as low
78
-------
Table 1: Results of Gas Production and Composition Measurements During
Anaerobic or Aerobic Decomposition of Solid Waste
Effect ,
Studied j
Mois-
Condi-
4- -I f\r\
U i Uii
Temper-
ature
Size
Density
Open to
Air
Con- j*
tainer ,-
lumber /
1
2
5
7
9
10
15
6
13
14
11
(1,7,
9)*
4
18
(15)
12
(1,2,
5,7,
9)*
16
17
3**
18**
nitial
loisture
iontent
% d.w.)
36
36
36
36
36
60
78
99
99
99
36
36
78
78
78
36
36
36
36
36
28
Weight of
Solid
Waste (kg)
65.0
66.4
67.3
66.4
67.3
69.1
67.3
67.7
79.5
76.8
69.5
66.2
60.5
60.4
67.3
80.5
66.5
55.0
71.4
70.0
71.4
Dry Density
(kg/m3)
334
393
345
368
399
342
375
386
436
403
356
367
310
356
375
421
368
335
406
375
399
Tempera-
ture
17
17
17
17
17
17
17
17
17
17
26
17
17
17
17
17
17
17
17
17
17
Size
(cm)
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
12.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
Average Maximum
Gas Pro- Combus-
duction tifale
During Sas
First Composi-
300 d. tion
(m£/kg.d) (%)
0.29 ?m>
3.50 -
5.63
0.77 12£H9
0.43 15S&H,
3.87 1*H~
12.9 - <•
17.8
15.8
20.2
1 . 07 5%H7
0.50 7-1 5%H~
C.
1.63 50%CH.
9.03 - H
12.9
1.23
2.12 0-15%H2
9.7 15%H2
« —
_
Average values of the containers indicated.
Sealed but gas outlet left open.
79
-------
Fiqure 4
Temperature in Container 7, 10, 13, 16,
and 17 During the First 200 Days as
Averaged for the Thermocouples Located on
Top, Middle and Bottom in the Sol id Waste
100 20O
Time (days)
Figure 5
Cumulative Gas Production in
Fifteen Containers
300
Table 2: Composition of the Solid Waste Before Shreddinq Collected
on Thursday, January 15, 1976
food waste
garden waste
dirt
plastic
paper
metal -ferrous
metal -nonferrous
glass
textiles
wood
This Study
% of dry weight
14.4
3.1
14.9
2.8
36.5
11.8
2.9
6.8
0.7
1.8
US-EPA (25)
% of dry weight
n.i
6.9
8.3
2.8
48.6
11.1
11 .1
8.3
0.7
2.1
Reinhardt and Ham (26)
% of wet weight
15.3
13.8
7.2
3.9
46.2
6.7
6.7
10.1
1.6
1.1
80
-------
as 5% of these initial rates. This may
indicate a zero-order reaction rate at
high moisture contents. The stepwise
pattern further shows that a major portion
of the solid waste, varying between 30%
and 75%, is rapidly degradable within a
relatively short period of time. The
shape of the other cumulative gas produc-
tion curves generally do not show this
stepwise pattern and resemble more closely
a parabolic or inverted logarithmic curve
possibly reflecting half- or first-order
reaction rates. The lowest gas production
occurred in the container with the lowest
moisture content.
The collected gases of all containers
were analyzed weekly or less frequently
when the composition did not show large
variations. The results in Figure 6
clearly show the absence of 0? indicating
that anaerobic conditions are prevalent.
The N2, initially present at 797., is
rapidly displaced by the generated COj
which then becomes the major component in
the gas phase. The highest C02 content
was generally observed in the containers
with the highest moisture content.
Comparison of the gas production rates
in the high moisture content containers
is due to the CO? "bloom." After approx-
imately 50 days.8 of the 15 sealed con-
tainers showed hydrogen in the gas phase
which amount peaked after approximately
100 days and gradually decreased thereafter.
Only one container filled with large sized
solid waste (Number 4) so far has
experienced production of methane (Table 2)
at a volume percentage of 50%. The methane
appeared immediately in the container and
did not show a sequential pattern in which
the methane generation follows the C02
bloom (19). The gas composition data
therefore indicate that most containers
have just completed the acid hydrolysis
phase characterized by C02 and Hg genera-
tion and that the methane fermentation
will probably start in most containers
after more than a year period. Thus,
although most of the containers did not
produce any energy yielding methane gas
in large quantities, as COj was the main
component in the gas phase, the results
of the first phase of this study are
important to assess the impact of environ-
mental conditions on the CO? formation.
Bishop (18) indicated that CQ2 can diffuse
large distances through the soil and increase
the alkalinity in groundwater which wou Id
increase the corrosion potential.
Cell 14 . WT, Monturt
x^r^i
t^SL
a n
Cell 4 ,78 7 •% Moislun
O
o
Figure 6
The Gas Composition in Three
Representative Containers
A systematic evaluation, therefore,
was made of the factors that influence the
magnitude of the gas production during the
acid digestion phase. For that purpose
the average gas production rates during
the first'300 days were calculated and
correlated with the different environmental
conditions as shown in Figure 7. One of
the major factors influencing the average
gas production rate is indeed the moisture
content (Figure 7A). Increasing the
moisture content from 36% to 99%, a 275^
increase, resulted in an increase of the
gas production from 2.1 to 17.9 ml/kg.d,
i.e., an 852% increase. The increase is
most noticeable between 60$ and 78%
moisture content but tended to level off
at higher contents. While values averaged
for several containers show a clear trend,
significant variability exist among con-
tainers maintained at identical conditions.
The highest gas production at the^36%
moisture condition, for example, is 265%
of the average value, while the lowest
rate is 14% of the average gas production.
At higher moisture contents the variabil-
ity becomes less as the highest rate at
99°/ moisture is 1137. of the average, and
the lowest rate 88% of the average. It is
further interesting to note that the
81
-------
SO 50 70 90
26 0 5 O 15 20 25 XQ 380 420
ixt t*C) S-i«(cm] Oy D«n*.ry (kg-'m1 )
Figure 7
Relation Between Gas Production Averaged
Over the First 300 Day Monitoring Period, and
Moisture Content (A), Temperature (B), Sol id
Waste Size (C), and Dry Density (D)
hydroqen oas is only produced in the con-
tainers with a low moisture content,
possibly indicating that at hiah moisture
contents hydroqen acceptors exist. Under
such condition the cellulose hydrolysis
step may result in the formation of
significant quantities of aldehydes or
alcohols. Since a high moisture content
results in a hiqh rate of gas production,
an inverse relation tends to exist between
rate of qas production and maximum
hydrogen content in the aas phase.
A second important factor, the tem-
perature, also tends to increase the rate of
qas production. Excluding containers 2
and 5, that did not have any Hj, it can be
calculated that Increasing the temperature
from 17°C to 26"C (a 9°C increase) in-
creases the rate of gas production from 0.50
to 1.07 ml/kq.d. (a 214% increase). However,
if the results of containers ?. and 5 are
included, obviously no temperature effect
is observed (Figure 7B). Furthermore, the
larne variability at such low qas produc-
tion rates prevents any firm conclusion.
The size of the solid waste tended to
have a noticeable effect on the rate of
qas production (Figure 7C). Decreasing
the size of the solid waste by a factor
of 10 increased the rate of gas production
by a factor of 7.9, and this relation was
approximately linear in the intermediate
range. Of all containers evaluated,
methane was only produced in the one with
the large size of solid waste. The
methane formation in this container may
well be due to the absence of shredding
which mechanical operation in effect may
have mixed the solid waste so well that
it dispersed bacterial nutrients to sub-
optimum concentration. A more likely
explanation, however, is that the shredding
of solid waste exposed a larger surface
area of cellulosic materials thereby
enhancing the cellulose hydrolysis. This
results in a rapid free volatile fatty
acid formation, and thus depresses the pH
to values toxic to methanogenic bacteria.
If this hypothesis is true, it indicates
that milling of solid waste will enhance
its degradation by hydrolysis and methane
fermentation as long as sufficient buffer
capacity is present; for example, resulting
from the addition of sewage sludge.
Increasing the density of the solid
waste tends to decrease the rate of gas
production (Figure 7D) which is to be
expected since compaction tends to decrease
the effective surface area exposed to
enzymatic hydrolysis. Baling of solid
waste to high densities is therefore
expected to result in very low qas produc-
tion rates, a finding actually reported
by McCabe (24).
The present study noted only methane
present in the container with the large
size solid waste. Using shredded solid
waste fractions, Merz (21) observed a
maximum CH4 content of 0.9% even though a
wide range of moisture contents was
tested. Even in the larae solid waste
container Rovers and Farquhar (19) only
noted a 2.895 methane content. Ramaswamy
(22), however, noted stable methane
fermentation often as little as 40 days
after the initiation of th<; tests. Care-
ful examination of this data (Figure 8)
show that the methane content does not
increase until the pH of the solid waste
moisture Increases beyond 5.0. The high
food waste content (primarily dog food)
may have resulted in a sufficient amount
of NHg released during the degradation
82
-------
300
. 200 —
•a
a
-
100
—I— —I— ,—
V Pfeffer (1973) ol J5 «C
I Merz (1964)
A Merj and Stone (1968) ^
0 Romaswamy (1970) at 35"C
• id al 25 "C
0 id. at 55 °C
4 Rovers and Fcrquhor (1973)
O Cooney and Wise (1975)
10 50 100 500 1000
Moisture Contenl (% of Dry Weight)
Figure 8
Rate of Gas Production, Gas Composition, pH
and Fatty Acid Content as Measured by
Ramaswamy (22)
of the amino acids to counteract the pH
decrease resulting from the free volatile
fatty acid formation. Thus, addition of
strong buffering substances may well be
necessary to initiate the methane fermen-
tation in shredded solid waste, or solid
waste subject to vigorous cellulose
hydrolysis resulting from large water
additions. Figure 8 further shows a
sequential gas production pattern with
an initial aerobic-anaerobic phase followed
by the C0£ "bloom" and the methane fermen-
tation.
The importance of the moisture content
on the gas production (Figure 7A) is con-
firmed by the result of other studies as
shown in Figure 9, possibly indicating
that linearly increasing gas production
can be realized by a logarithmically
increasing moisture content. The highest
results are obviously obtained by Pfeffer
(13) and Cooney and Wise (14) employing
anaerobic digesters with more optimum
mass transfer conditions. The moisture
content not only influences the total
amount of gas produced, but also deter-
mines the extent of the methane fermenta-
tion. The data by Ramaswamy (22), Merz
and Stone (20) and Merz and Stone (27)
Figure 9
Effect of Moisture Content on Total
Production (I/kg dry weight)
Gas
indicate that increasing moisture contents
increase the maximum methane content in
the gas phase up to 55 to 60%. Merz and
Stone (20) further noted that increasing
moisture contents increased the Hg in the
gas phase. Merz and Stone (27) in later
studies and Ramaswamy (22) did not note such
1 arne effect. The data of the present study
show an inverse relationship between the H2
and the moisture content (Figure 10).
The observed effect of temperature
(Figure 7B) was also noted by Merz (21),
as plotted in Figure 11, it shows a
maximum rate near 35°C, the optimum for
anaerobic mesophylic digestion. The gas
production in landfills can therefore be
considerably lower than maximum possible
rates attainable at higher temperatures.
Using the temperature data from the present
study, and from Ramaswamy (22), it is
possible to calculate the activation energy
of the reaction as defined by:
£n k2/k] = E/R (1/T! - 1/T2) (1)
k-j ,k£ = reaction rate contents
at TI and T2> respectively
83
-------
Ortly II970&
Of WC
• Romoi-omy
m eve
OT (1970)
0! 55-C
0 Uvrt orwJ S'ote (rS63j
A M«il and Stone 11966)
A Thu Study
Figure 10
Effect of the Solid Waste Moisture on
Methane Content in the Gas Phase
' 15
10
A This Study
O Romasv.'Qiny
L
J I
10 50 100 500
Moisture Content (%}
Figure 12
Effect of Moisture Content on the
Activation Energy of Gas Production
fOOO
o
0
*
f 100
O
C
jO
*-s
c
9 10
<_>
1
al
0
O
1
x' *•«
/ \ o Conloins'
/\ " Container
\ o Container
\ -i Container
^TT A , • Container
/J • ** \ * Container
/• * * \ • Container
.!«. \ • Container
/d' ala' \
//m0 *'*' . . \
»t rlnj ( ' o*, «^ .,« \
/ Ds 5 ' ' ' 'f0; 'f5*4' 'a' ' \
/ \
/ A" •; •-!••/ \
/ i ,° 1 t i .! 4" F\
A
B
C
D
E
F
G
H
-
20
30
Temperature (°C J
50
Figure 11
Effect of Temperature on the Rate of
Gas Production (21)
, ,
= Activated Energy
= Gas constant
= Absolute temperatures.
At a moisture content of 400% and tempera-
tures of 25°C and 35°C, the gas production
rate data from Ramaswamy (22) result in an
activation energy of 18,000 cal/mole, and
15,900 cal/q-mole, respectively. The data
in the present study at a moisture content
of 36% and temperatures of 17 and 26°C
result in an activation eneray of 14,500
cal/g-mole. The magnitude of these values
indicates that the rate of gas production
which parallels the hydrolysis of cellu-
lose is chemical ly-rate controlled and not
diffusion-rate limited (Figure 12).
CONCLUSIONS
The present study measured the rate
and composition of gases released durinq
anaerobic depredation of solid waste. The
major gases "observed were CC>2, H2 and LH4-
The maximum rate of gas produced was 6.0
I/kg dry weight during the 300-day testing
period. It was further noted that increas-
ing moisture contents increased the rate of
gas production. A similar effect
84
-------
was caused by increasing temperatures and 9.
decreasing solid waste size. Increasing
density of the solid waste tended to
decrease the gas production. The \\2 was
primarily detected in the containers with
the 36% moisture content, while the CH4
was found in the container with the 10.
unshredded refuse, possibly indicating
that pH effect may exert an important
effect on the initiation of methanic pro-
duction phase. 11.
REFERENCES
Pfeffer, J. T. "Temperature Effects
from Organic Refuse." Grant No.
EPA-R-800776 (April, 1973).
Cowling, E. B. and Brown, W.
"Structural Features of Cellulosic 12.
Materials in Relation to Enzymatic
Hydrolysis," in Celluloses and Their
Applications, Advances in Chemistry
Series. No. 95 (1969).
Stone, J., et al_. "Digestibility as
a Simple Function of a Molecule of
Similar Size to a Cellulose Enzyme,"
in Celluloses and Their Applications,
Advances in Chemistry Series No. 95
(1969).'
Klein, S. A. "Anaerobic Digestion of
Solid Wastes," Compost Science, H,
6 (1972).
13.
14.
Dubos, R. J. "Influence of Environ-
mental Condition on the Activities of 15.
Cellulose Decomposing Bacteria in
Soil." Ecology, £, 12 (1928).
Heukelekian, H. "Decomposition of 16.
Cellulose in Fresh Sewage Solids,"
Industrial and Engineering Chemistry,
11, 928 (1928).
Hazeltine, T. R. "Addition of Garbage 17.
to Sewage," Water Sewage Works Journ.,
86, R 151 (195TT:
Golueke, C. G., and McGauhey, P. H.
"Comprehensive studies of Solid Waste
Management, First Annual Report," 18.
U.S. Public Health Service, Bureau of
Solid Waste Management Report SW-3RG,
Washington, D.C. (1970).
Maki, L. "Experiments on the
Microbiology of Cellulose Decomposi-
tion in a Municipal Sewage Plant."
Anthonie Van Leeuwenhoek, 20, 185
(1954).
Hill, M. T. "Digestion Studies on
Paper Pulp." Sewage Works Journal,
Jl, 864 (19397:
Uesaka, S. R. et §]_. "Effects of
Trace Elements on the Activities of
Rumen Bacteria With Special Reference
to the Differences of the Effects
Appearing in Cellulose Digestion
Protein Synthesis and Vitamin B]2
Syntheses by Rumen Bacteria."
Biedermanns Zentr B. Tierenahr, 13,
10 (1941).
Chan, D. B., and Pearson, E. A.
"Hydrolysis Rate of Cellulose in
Anaerobic Fermentation." University
of California at Berkeley, Sanitary
Engineering Laboratory, Report
SERL-70-3 (1970).
Pfeffer, J. T. "Temperature Effects
on Anaerobic Fermentation of Refuse."
Biotechnology and Bioengineering, 16,
771 (1974).
Cooney, C. L., and Wise, D. L.
"Thermophilic Anaerobic Digestion of
Solid Waste for Fuel Gas Production."
Biotechnology and Bioengineering, 17,
1119 (1975)7
Eliassen, R. "Decomposition of Land-
fills," Amer. Jour. Public Health, 32_
9, 1029 (1942).
Carpenter, L. V., and Setter, L. R.
"Some Notes on Sanitary Landfills."
Amer. Journ. Public Health, 30, 385
(1940).
Merz, R. C., and Stone, R. "Special
Studies of a Sanitary Landfill."
United States Public Health Service.
Bureau of Solid Waste Management
Report EPA-SW 8R6-70 (1968).
Bishop, W. D. et aJL "Water Pollution
Hazards from Refuse Produced Carbon-
dioxide." Advances Water Pollution
Research, Ed., Jaag, 0., and Liebman,
H., Water Pollution Control Federation,
Washington, D.C. (1967).
85
-------
19. Rovers, F. A., and Farquhar, G. J.
"Infiltration and Landfill Behavior."
Jour. Environ. Engr. Division, ASCE,
99, 671 (1973).
20. Merz, R. C. and Stone R. "Factors
Controlling Utilization of Sanitary
Landfill Site," Final Report Project
EF-00160-03, May 1960-May 1963, Public
Health Service, Washington, O.C.,
(1963).
21. Merz, R. C. "Investigation to Deter-
mine the Quantity and Quality of Sases
Produced During Refuse Decomposition."
University of Southern California to
State Water Quality Control Boards,
Sacramento, California (1964).
22. Ramaswamy, J. N. "Nutritional Effects
on Acid and Gas Production in Sanitary
Landfills." Ph.D. Thesis, Department
of Civil Engineering, West Virginia
University, Morgantown, W.V. (1970).
23. Jackson, A. 6. "Evaluation of Sani-
tary Landfill Gas and Leachate Produc-
tion." Systems Technology Corporation,
First Annual Report, Dayton, Ohio
(1975).
24. McCafae, D. J. "Progress Report of
Efforts Completed During the Second
Year of Baled and Unbaled Solid Waste
Studies." System Technology Corpora-
tion, Xenia, Ohio (1976).
25. U.S. EPA "National Survey of Commun-
ity Solid Waste Practices, 1968,"
U.S. Environmental Protection Agency,
Cincinnati, Ohio (1968).
26. Farquhar, G. J., and Rovers, F. A.
"Gas Production During Refuse Decom-
position." Water, Air and Soil
Pollution, 2_, 483 (1973).
27. Merz, R. C. and Stone, R "Factors
Controlling Utilization of Sanitary
Landfill Site," Final Report Project
EF-00160-05, January 1964-December
1965, Public Health Service,
Washington, D.C. (1966).
86
-------
LEACHATE PRODUCTION AND VIRAL SURVIVAL
FROM LANDFILLED MUNICIPAL SOLID WASTE*
Dirk R. Brunner1, Arthur W. Bales1 and R. Wigh2
U.S. Environmental Protection Agency, Cincinnati,'Ohio
2
Regional Services Corporation, Columbus, Indiana
ABSTRACT
Results of five years of monitoring of a 435-ton batch-operated experimental land-
fill were presented. Leachate production, the major objective of the experiment,
was emphasized. The concentration histories of selected contaminants, COD, Fe, Ca, Cl,
selected metals, and indicator organisms were presented and discussed. Observed mass
removals were compared to other values reported in the literature, and to the initial
mass of solid waste disposed.
Work performed to achieve a secondary objective of the experimental landfill
survival of viruses within the mass of landfilled solid waste, was also reported.
Samples of shredded municipal waste, inoculated with poliovirys, were placed at three
levels within the landfilled solid wastes. Laboratory studies were also performed to
determine the survival of viruses and bacterial indicators of fecal contamination
which were inoculated into leachate from the experimental landfill.
*Manuscript of the paper not received in time for publication.
87
-------
DESIGN CRITERIA TOR GAS MIGRATION CONTROL DEVICES
Charles A. Moore
Iqbal S. Ral
Department of Civil Engineering
The Ohio State University
2070 Neil Avenue
Columbus, Ohio 43210
ABSTRACT
Principles of landfill gas migration under total and partial pressure gradients are
discussed. Analytical principles relating to the design of control devices are presented,
and concepts for field implementation of vent, barrier and hybrid systems are delineated.
Computer models for simulating gas migration both with and without control devices are
described. Finally, several alternative protective installations for a typical landfill
are evaluated and compared.
INTRODUCTION
Migration of methane gas around sani-
tary landfills constitutes a hazard in that
the gas may accumulate to explosive concen-
trations in buildings adjacent to the land-
fill. The gas forms an explosive mixture in
the range of 5 percent to 15 percent methane
in air.
Previous research at the Ohio State
UniversityCD has provided analytical tech-
nique for predicting the time-concentration
profiles for methane around landfills. Com-
puter programs'^) are available for studying
site specific situations, and design
charts^) based upon simplifying assumptions
may be used to estimate distances of migra-
tion for planning purposes.
Current research efforts are directed
toward developing design criteria for in-
stallations to control methane migration.
This paper describes the scope of the re-
search and presents findings to date.
TYPES OF CONTROL DEVICES
Figure 1 delineates several types of
control devices. Major classes include:
1. trench vents •- trenches are con-
tinuously cut around the landfill and filled
with coarse gravel. Such vents may vent
naturally to the atmosphere or may undergo
forced convection by mechanical pumping into
or out of the trench.
2. pipe vents - similar to trenches
except that they are placed at intervals
around the landfills. Normally some type of
convective flow must be used if such pipe
vents are to be effective.
3. barriers - constructed similarly to
trench vents except that the trenches are
filled with saturated compacted clays or
other impervious liner materials.
4. hybrid systems - a combination of
trench vents backed by impervious barriers.
The trench vent may or may not involve
forced flow.
88
-------
TRE NCR
VENTS
unforced
venting
P. I
The costs involved in the construction,
maintenance and operation of these control
devices vary widely, and it is important
to optimize design to reduce cost and in-
crease effectiveness.
COMPUTER PROGRAMS FOR OPTIMIZATION
methane
removal
forced
exhaust
forced
recharge
P»
PIPE
VENTS
BARRIERS
HYBRID
Because of the many variables involved
in the design of a gas migration control
system, it is useful to be able to simulate
the effectiveness of alternative design con-
figurations on a computer. This approach
allows for economically evaluating alterna-
tive solutions in order to select the opti-
mum configuration. Such an approach also
allows the designer to determine which de-
sign aspects most influence the effective-
ness of the system so that important aspects
can be carefully controlled during field
installation. Finally, if the installed
system does not perform as efficiently as
desired, the computer simulation can be
used to determine what modifications would
most economically remedy the problem.
It is not the purpose of this paper to
describe the details of the computer simu-
lations. Therefore, suffice it to say that
the several codes developed include treat-
ment of:
1. soils displaying a distribution of
pore sizes,
2. combined pressure and diffusional
transition region flow,
3. bicomponent or multicomponent gas
systems, and
4. two or three dimensional problems
Computer costs on the IBM 370/168 run from
$25 to $2000 depending upon the complexity
of the particular situation; however, many
practical design problems cost of the order
of $100.
Figure 1 - Types of gas migration control
devices.
89
-------
160m
1°
5 mph wind
480m
16m
32m
LANDFIL I
SOIL
fine silt
||
/;
(
rmpermeoble
Figure 2 - Landfill configuration chosen for design problem.
TYPICAL DESIGN PROBLEM
In order to demonstrate some aspects
of design of gas migration control devices,
a specific case was developed. The config-
uration chosen is shown in figure 2. The
landfill is circular in plan and of radius,
160 meters. The landfill is 16 meters deep.
Impervious bedrock (or a groundwater table)
is encountered at a depth of 32 meters. The
soil beneath and surrounding the landfill
is a fine dry silt having a porosity of 0.7.
Venting at the ground surface is that which
should be achieved by a uniform 5 mile per
hour wind. In order to limit computer
storage, a pure air boundary was imposed at
a radius of 480 meters. The methane gener-
ation rate within the landfill was taken to
be 3.167 cubic meters/second/cubic meter of
refuse. For a three component case carbon
dioxide was generated in the landfill at a
rate of 1.357 cubic meters/second/cubic
meter of refuse. This configuration was
chosen for two reasons:
1. it represents a realistic situa-
tion, and
2. it poses a methane migration haz-
ard in that the 5 percent methane contour
migrates approximately 150 meters (450
feet) beyond the edge of the landfill.
Figure 3 shows contours of methane and
carbon dioxide concentrations around the
landfill when steady state is reached
(approximately 20 years). The top two draw-
ings give the results from a computer run
simulating the simultaneous transport of
carbon dioxide and methane into air while
the lower drawing gives the results from a
computer run simulating the transport of
methane alone into air. The three component
run shows slightly greater methane migration.
However, because the difference is small
and because the two component program is
more economical to run, all results shown
in this paper are for the two component
configuration.
The remedial measures to be considered
in this paper are based upon the assumption
that the landfill was constructed without
gas migration control devices. At the end
of ten years, the relatively high methane
concentrations surrounding the landfill
resulted in the decision to install a gas
migration control facility. The design con-
straints on the facility were that it was to
be of the venting trench type, was to be lo-
cated 32 meters from the edge of the land-
fill, and was to be equal in depth to the
base of the landfill (16 meters). The ques-
tions raised are:
1. Is such a facility capable of con-
trolling methane migration?
2. Will it be necessary and/or advan-
tageous to use forced convection in the
trench?
90
-------
t—
0.
IU
Q
c
SfSpt:; : . . : ,
\ \o\ i\ 3: compos
,J\ \ ;\j; :-\fflH--. e»4.tiraHi.4j
L\ I :\ i
' -III : \ '• •
1 ':' ' '' ' ''• '. '. : ': ' :
,nt
:
— -; '.'].• •/:.-- \-~ \---- • L.r_i-
:..i ..•...!.:.:. ! -. t IV -V ; \ V A 2 coir
NJ ^ i :vrl ES±
'" r ' r ' v " ' "r f ":"' ';' rjr' ff
•_ DISTANCE
-
pon.
»«™
'•
' '
ant
-- -:-
;-
-1-
Figure 3 - Methane and carbon dioxide concentrations for two and three component versions
of computer program.
DESIGN PROCEDURE
The first step in the design procedure
is to determine if the basic configuration
selected is capable of providing the desired
controls. In order to do this, a computer
simulation was performed for a perfect un-
pumped trench vent. Such a trench vent is
one in which the total pressure remains
atmospheric but from which all methane is
instantaneously removed by an undisclosed
means. Of course, such a situation cannot
be realized in the field; however, it does
represent a limiting condition which could
be approached in practice.
The results of this computer simulation
are shown in figure 4 as a plot of reduction
ratio versus distance away from the land-
fill. The reduction ratio, to be used in
several subsequent figures, is the ratio of
the methane concentration at a given point
and at a given time with a control device
operating divided by the methane concentra-
tion at that same point and at that same
time without the control device operating.
Reduction ratio values have the following
significance:
1. A reduction ratio of 1.0 implies
that the control device in fact has no
effect on the methane concentration.
2. A reduction ratio greater than 1.0
implies that the "control" device actually
causes an increase in methane concentration.
3. A reduction ratio less than 1.0
implies that the control device is effective
in reducing methane concentrations at that
point and at that time. The lower the re-
duction ratio, the more effective the device.
In all of the figures in this paper, the
reduction ratio is plotted when steady state
has been attained after the control device
begins to operate.
The distance scale is the ratio of the
distance to a given point divided by the
radius of the landfill (160 meters). The
data shown on the figure are for points at
the elevation of the base of the landfill.
Reference to figure A shows that the
hypothetical control device which provides
for complete removal of all methane instan-
taneously is indeed effective in reducing
methane concentrations. Effectiveness is
marginal between the landfill and the trench;
however, significant reductions are achieved
beyond the trench vent.
Given that it is possible to control
methane migration using the configuration
91
-------
1.2
1.8 2.4
DISTANCE
3.0
Figure 4 - Methane reduction ratios for
perfect methane removal
1.8
DISTANCE
2.4
3.0
Figure 5 - Methane reduction ratios for
unforced venting.
proposed, it is now necessary to determine
how this configuration is to be implemented
in the field. The first logical choice is
to simply dig the trench, backfill it with
gravel and allow unforced venting to occur.
This situation is simulated by setting the
total pressure within the trench to one at-
mosphere and increasing the efficiency of
venting at the surface. Figure 5 shows the
reduction ratio for this case. It is seen
that significant reduction of methane con-
centration is realized. This design alter-
native could be considered to be practical.
The next alternative considered is
forced exhaust. The system consists of fans
installed every 15-24 meters (50 feet)
along the trench and having a perfect seal
on the top of the trench. The fans remove
mixed gas from the system at a rate of Q
cubic feet per minute (cfm). Figure 6 shows
the methane reduction ratio for values of
Q of 30,150 and 300 cfm. It may be seen
that the methane concentrations increase
between the landfill and the trench and
decrease beyond the trench. For Q=150 cfm
the 5 percent methane level is retracted to
a distance of 69 meters. This design would
probably be cosidered to be effective in
controlling methane migration. However, it
is important to note the possible effects
of the higher methane concentrations be-
tween the landfill and the trench. The
higher concentrations exist because the ex-
haust pumps actually attract methane from
the landfill. Now, if the pumping system
were shut down either intentionally or ac-
cidentally, the high methane concentrations
between the landfill and the trench would
provide a high diffusional driving force
for transport of methane beyond the trench.
Thus the consequences of system shutdown
could be significant.
The next alternative considered is
identical to the forced ventilation system
shown except that air is pumped into the
trench rather than out of it. Figure 7
shows the reduction ratio for Q=30,150 and
300 cfm. Significant reductions are found
both between the landfill and the trench
and beyond the trench. The reductions are
greater for a given Q than those achieved
by the exhaust venting system. Moreover,
the possible detrimental effects of system
shut-down are lessened since there is no
methane buildup between the landfill and the
trench.
Figure 8 shows a comparison of the sev-
eral systems considered and for Q=300 cfm.
Finally, figure 9 plots methane concentra-
tion contours for the several systems at
steady state.
92
-------
06
1.2
1.8 2.4
DISTANCE
Figure 6 - Methane reduction ratios for
pumped exhaust system.
1.2
1.8 2.4
DISTANCE
3.0
Figure 7 - Methane reduction ratios for
pumped recharge system.
SUMMARY AND CONCLUSIONS
,8
DISTANCE
3.0
Figure 8 - Summary of methane reduction
reduction ratios for the
several design alternatives.
a. no control device
b. perfect methane removal
c. natural venting
d. forced recharge venting
e. forced exhaust venting
This paper has presented a typical de-
sign situation involving migration of meth-
ane to an unacceptably great distance from
a sanitary landfill. Control measures in-
volving both unforced and forced venting
trenches were evaluated by computer simula-
tion. The unforced trench configuration
was effective. The forced exhaust trench
configuration also proved effective; how-
ever, shutdown of the system could result
in relatively rapid increases in methane
concentration beyond the trench. The
forced recharge configurati.on was the most
effective system studied and did not pose
as great a threat of methane buildup after
system shutdown as did the forced exhaust
configuration.
The reader is cautioned against inter-
preting the conclusions of this design ex-
ample too broadly. In particular, the type
of gas migration control devices which
proved most satisfactory in the present ex-
ample may or may not prove so for other
cases. It is important that gas migration
control devices for a particular site be
designed in a site-specific manner.
93
-------
DISTANCE
Figure 9 - Summary of steady state methane concentrations
for the several design alternatives considered.
a. no control device
b. perfect methane removal
c. natural venting
d. forced recharge venting
e. forced exhaust venting
ACKNOWLEDGMENT
This research was supported in part by
the U. S, Environmental Protection Agency,
National Solid and Hazardous Waste Research
Center, from Contract No. 68-03-2416.
REFERENCES
1. Alzaydi, Ayad A., Flow of Gases through
Porous Media, Ph.D. dissertation, The Ohio
State University, Columbus, Ohio, 1975.
Dissertation Abstracts No. 76-3367.
2. Rai, Iqbal S., Mathematical Modeling
and Numerical Analysis of Flow of Gases
around Sanitary Landfills, Ph.D. disserta-
tion, The Ohio State University, Columbus,
Ohio, 1975. Dissertation Abstracts
No. 76-18030.
3. Moore, Charles A., Theoretical Approach
to Gas Movement through Soils; Gas and
Leachate from Landfills: Formation,
Collection and Treatment; Rutgers University,
March, 1975.
94
-------
MODELING OF LEACHATE AND SOIL INTERACTIONS IN AN AQUIFER
Martinus Th. van Genuchten, George F. Finder and Walter P. Saukin
Water Resources Program
Department of Civil Engineering
Princeton University
Princeton, N.J.
ABSTRACT
The movement of leachate emanating from a hypothetical landfill is de-
scribed by the two-dimensional convecti ve-dispersi ve equation. Because the mass-averag-
ed velocity of the convecting fluid appears as a coefficient in the transport equation,
it is also necessary to solve the partial differential equations governing saturated-
unsaturated fluid flow. Solutions of the resulting coupled set of equations for a hy-
pothetical landfill located adjacent to a river provides considerable insight into the
subsurface movement of landfill leachates.
INTRODUCTION
The effective design of a waste-dis-
posal site requires an a priori understand-
ing of the movement of landfill generated
leachates into the subsurface. This move-
ment is dependent upon the geologic and
hydrologic character of the site as well
as the physical and chemical interactions
between the leachate and the soil. To
forecast the movement of dissolved mater-
ials from the landfill one must depend
either upon existing records of migration
or upon models of the system. Because
leachates generally move very slowly and
data collection and analysis programs are
both time consuming and expensive, records
of migration are usually not available.
Consequently simulation models, particu-
lary mathematical models, can be useful
tools, not only to obtain information
necessary for rational landfill design,
but also to formulate remedial schemes
when unacceptable groundwater contamination
has already occurred.
THEORETICAL DEVELOPMENT
A mathematical model is formally the
solution of a set of equations which des-
cribe the physics underlying the movement
of a convecting fluid and its dissolved
chemical constituents. For systems of the
complexity encountered in landfill simula-
tion, these solutions are generally ob-
tained numerically, although for some
simplified situations analytical expres-
sions do exist (Larson and Reeves, 1976).
The governing equations are based
upon the conservation principle (mass,
momentum and energy), augmented by con-
stitutive relationships and proper initial
and boundary conditions. After combina-
tion and simplification the governing equa-
tions reduce to a coupled pair of non-
linear, second-order partial differential
equations; one descriptive of saturated-
unsaturated fluid flow and the other char-
acterizing the species transport. Once
the governing equations are defined, their
solution can be generated by a straight-
forward process of numerical manipulation-
The main problems encountered during the
simulation of non-conservative transport,
therefore, are not so much a question of
mathematical sophistication, as one of in-
adequate information on the chemical be-
havior of the dissolved ions in the system
and estimation of the parameters entering
the model.
Governing Equations
The equation governing saturated-
unsaturated fluid flow in a vertical cross-
section is given by
95
-------
3x
„_ i _3h , x
3z iKz 3z Kz;
where
(1)
k=krk is the hydraulic conductivity
k =k (h) is the relative hydraulic con-
ductivity [L°],
ks is the hydraulic conductivity at
saturation [LT ],
6 Is the volumetric moisture
content
[L],
n is the porosity [L ] ,
S is the specific storage coeffi-
5 _l
cient [L ],
3S
C is the soil moisture capacity
S is the degree of fluid satura-
tion [l°],
h is the pressure head [L] , and
Q is a fluid source (or sink) func-
tion [T"1].
To solve equation (1) additional informa-
tion on the relationship between relatt-
ve hydraulic conductivity and pressure
head, and degree of saturation and pres-
sure head is required. These functions
are derived experimentally for each soil
type encountered; typical curves for a
coarse (sand) and fine (loam) soil are
given in Figure 1 ,
The transport of dissolved ionic
species in the leachate is described by
the mass transport equation, which for a
sorbing medium is written as
IT <9Dxx If + 6Dxz If - V)
(6c) - p |f- - a6c + Qc*
(2)
where
c is the solute concentration [ML ],
c* is the concentration in the source (or
sink) fluid[ML~3],
D is the hydrodynamic dispersion co-
: efficient [tV],
q is the volumetric (phase averaged)
fluid velocity [LT'1],
p is the (dry) bulk density of the soil
[ML"3],
S is the adsorbed concentration [M ], and
a is the first order rate constant for
decay [T*1].
Examination of Equation (2) reveals that
the mofsture content, 9, and the volu-
metric fluid velocity,q,are required be-
fore the concentration can be obtained.
The moisture content can be read from
Figure 1, given its value at saturation
and the pressure head, and the velocity
can be evaluated through Darcy's law:
111
qx = " x 3x
(3)
The dispersion coefficient, 0, represents
the effects of both molecular diffusion
and mechanical dispersion. Scheidegger
(!962) derived formulae for this coeffi-
cient, assuming a saturated system and
isotropy of the medium with respect to
the dispersivities. These formulae are
assumed to hold also for unsaturated condi
tions, and given by
qxqx V7
96
-------
1.0
SAND
LOAM
1.0
0.8
0.6
0.4
0.2
O.I
0.01
-200
-400
O.OOI1
\
\
\
-4
-10
h(cm)
-40 -100
h(cm)
-400
Figure 1. Degree of fluid saturation (a) and relative hydraulic conductivity
(b) versus pressure head for the two soil materials used in the
example transport problem.
D = D
xz zx
- DT)
-------
LTD LOAM
SAND
400
Figure 2.
Geometry of the physical system and its discretization in
elements (a) true scale, and (b) 5:1 vertical exaggerati
into finite
exaggeration.
APPLICATION
To demonstrate the utility of the
model in evaluating the impact of a land-
fill on groundwater quality, a landfill
located in a typical hydrological environ-
ment is considered. The physical system
is illustrated in discretized form in
Figure 2. The domain is bounded below
by an impermeable (clay) layer, and sym-
metrically on each side by two small
rivers, assumed to be 800 m apart. Be-
cause of the hydrological symmetry of the
area only one half of the problem is con-
sidered. The cross-section consists of
a 1 -1 !j m thick loam soil horizon over-
lying a sand aquifer. The following func-
tions are used to characterize the hy-
draulic properties of the two soil mater-
ials (see also Figure 1),
Table 1. Soil physical data used
in the example transport problem.
(Blh|)V
(alh )Yr
(6a)
(6b)
where 6r and 9s represent the residual and
saturation moisture content of the soil,
respectively. Values for the various con-
stants (3, y, a, b and r in equation (6)
are g iven in Tab le I.
var iabl e
units sand
loam
. s s
n, GS
er
e
Y
a
b
r
Ss
\
AT
i
cm/day 300
cm /cm 0
cm /cm 0
cm"' 0
2
cm 0
5
]
cm 0
cm 60
cm ^0
0
.45
.03!
.017*1
.5
.0667
.0
.0
.00022
.0
.0
.67
90.
0.50
0.10
O.OO'ftSl
1.5
0.0^
3-5
0.6^*
0.00020
60.0
^0.0
0.67
Precipitation and evaporation data,
typical for eastern Long Island, New York,
were used to calculate the net influx of
water at the soil surface. Figure 3 shows
98
-------
the eight-year averaged distributions of
monthly rainfall (R) and potential evapor-
ation (E ) which were used in the calcula-
tions. In order to obtain reasonable
estimates of the actual evapotranspirat ion
(Eg) the following reduction to E was
applied P
R
> E
- P
R + 0.9 (E - R)
R < E
Hence the net flux at the soil surface is
R =
n
R - E
R > E
- P
0.9 (R - E ) R < E
P P
The impact of the variable rainfall over
the year is clearly illustrated in Figure
^ wherein calculated levels of the water
table are presented. Simulation was
started on an arbitrary date, January
1, 1968 (t = -2 years), assuming an
arbitrary initial condition for the
pressure head, h. The landfill, located
100
Figure 3- Patterns of precipitation (R)
and potential evapotrans-
pi rat ion (E ) employed in the
transport problem.
WATER TABLE AT X = 221 m
LANDFILL
CONSTRUCTED
-2
234
ELAPSED TIME (YEARS)
Figure k Calculated water table elevations along the vertical at x = 221m. The
vertical dashed lines represent elapsed times at which calculated con-
centrations are presented.
99
-------
10
z
(m)
LOAM
SAND
t =0.612 YRS
(AUG 22,1970)
(DEC II ,1970)
-3OO -200 -100 0
h(cm)
100
O.fO 0.20 0.30 0.40 0.50
6 (cm3/cm3)
Figure 5- Calculated pressure head and moisture content profiles along the
vert ical at x = 221m.
halfway between the groundwater divide
and the river, was assumed to be con-
structed on January 1, 1970 (t=0). At
that time, the water table was stabilized
at approximately 8m above the impermeable
layer (about 3"i below the soil surface).
The water table data in the figure were
obtained at a position 221m, immedlately
downgradient of the landfill. The data
indicate a variation of approximately
35cm in the water table elevation during
the year. The influence of the variable
rainfall and evaporation pattern at the
same location is demonstrated in
Figure 5 by calculated profiles of
pressure head and moisture content along
the vertical. The profiles show a down-
ward movement of moisture during periods
of abundant rainfall (winter) and a
slow upward movement when evaporation
exceeds precipitation (summer). The
water table responds to this as expected:
rising in the winter and early spring
and falling near the end of the summer.
It is interesting to note that some
horizontal movement of moisture towards
the river takes place in the capillary
fringe region immediately above the
water table. In the present case, this
region is confined to about 10cm due to
the sandy make-up of the aquifer. Hori-
zontal movement in the capillary fringe
region will become much more important
when finer soil material is present. For
a loam aquifer, for example, this region
may easily extend to about 30cm (see also
Figure 1).
It is important to point out that
the water table data of Figure 4 and the
pressure head distributions of Figure 5
were obtained using eight-year averaged
monthly values of precipitation and
evaporation. The calculated results
therefore represent only seasonal trends:
moisture movement towards the water table
in the winter and upward movement during
the summer. The pressure head distribu-
tions will undoubtedly become much more
erratic when observed hourly (or daily)
rain and evaporation data are used. In
that case, the direction of flow, espec-
ially in the upper part of the unsaturated
100
-------
zone, will be reversed several times during
the day (or week). Such oscillatory
behavior will be damped out, however, in
the deeper layers of the profile, and it
is unlikely that it will affect to any
significant degree the transients of the
saturated zone where most of the leachate
movement will take place.
In this example, the landfill is
located midway between the groundwater
divide and the river. It is assumed
that leachate emanating from the landfill
is attributable to the downward movement
of net rainfall and dissolution of land-
fill contents. The concentration of the
solute in question is further assumed to
remain at an arbitrary 100 mg/1 level
within the landfill at all times. No
adsorption or decay processes are con-
sidered. The transport of the solute
is illustrated in Figure 6. Examination
of this figure reveals that the leachate
moves through the unsaturated zone to
the water table and then proceeds down-
gradient until it discharges into the
river. The concentration of the leachate
appears to remain high immediately below
the landfill. A sharp concentration drop,
however, is apparent when the concentra-
tion front reaches the ground water table.
Dilution of the leachate with the flowing
groundwater, along with some dispersion,
causes the concentration to drop to
approximately 15 mg/1 further down-
gradient from the landfill. The results
in Figure 5 show that significant amounts
of material are being discharged into the
stream after six or seven years. It is
further apparent that some solute is
transported through the unsaturated zone,
mainly in the capillary fringe region and
the region of water table fluctuations.
For the present case (i.e., a sandy aqui-
fer), significant pollution in the un-
saturated zone is, however, limited
to about 50cm above the water table,
depending upon the season of the year.
This unsaturated region of contamination
appears to become more significant further
downgradient of the landfill. The con-
tinuous, nearly horizontal, influx, of
solute into the capillary fringe region
and the slow upward movement during
periods of high evaporation, including the
dispersion effects, are responsible for
this presence in the unsaturated zone.
In this context, it may be inter-
esting to consider the values of the
longitudinal and transversal dispersivi-
ties used in the calculations (60 and
40cm, respectively). These values are
very high when measured against pub-
lished data in most soil physics litera-
ture. Several one-dimensional experi-
mental studies indeed indicate longitudin-
al dispersivities in the order of one
(Wood and Davidson, 1975) or only a few
cm (Kirda et al, 1973; Biggar and
Nielsen, 1976)- These studies, almost
without exception, are concerned with the
entrance, downward movement, and re-
distribution of a solute carrying pulse
of water. The temporal dimension of this
process is generally limited to only
a few hours or days. Simulations for
the present study are carried out over
a period of several years, using monthly
values of rain and evaporation which
keep the maximum fluid velocities
limited to only a few millimeters per day.
In addition, the time-frame of the
present model does not allow for the flux
oscillations near the soil surface which
occur over a day or between two con-
secutive days which exhibit different
rainfall and evaporation intensities.
Such an oscillatory mechanism would tend
to disperse the solute, if present, in the
unsaturated zone. The only way to include
these apparent dispersion effects into
the physical model is-through an increase
in the dispersivity. The adopted value
of 60cm for A, is obviously a first
estimate; additional numerical experi-
mentation seem necessary to better
define this parameter, (e.g., by com-
paring model results using increasingly
finer time dimensions).
Contrary to most soil physics
studies, groundwater quality studies have
generally used much higher values for
X and XT, especially when areal simu-
lation models are used. Typical values
in the 1iterature range from a few
meters (Pinder, 1973) to a seemingly
unrealistic value of five miles (Amend
et al, 1976). The argument for such high
dispersivities is the fact that small
scale heterogeneities in an aquifer can-
not be detected by large-scale models.
For example, when the convecting fluid
encounters a small clay lens, the stream
101
-------
0.52 YEARS
(JULY 9 . 1970!
1.02 YEARS
[JAN. 8 , 1971
2.01 YEARS
(JAN.5, 1972!
100
4.22 YEARS
(MARCH 21 , 1974)
_\Z_
400
Figure 6. Simulated concentration distributions after 0.52 (a) 1.02 (b) 2.01
(c) ^.22 (d) 6.25 (e) years of elapsed time.
102
-------
lines are diverted leading to an apparent
dispersion of the solute. Because the
macroscopic model is unable to include
each clay lens, the above apparent
dispersion must be lumped into the
dispersivity. The need for a large value
for dispersivity diminishes, however,
when the physical system becomes better
defined.
In the present example, the landfill
was located midway between the ground-
water divide and the river. A second
example was also considered wherein
the landfill was constructed above the
divide itself. Results for this case
indicated little movement away from the
landfill after ten years of simulation
due to the nearly horizontal groundwater
table under the divide. It was apparent
from this case that pollution was con-
fined to a small region in the immediate
vicinity of the landfill, although the
solute concentrations in the groundwater
reached a level of approximately 100 mg/1,
i.e., much higher than the average con-
centration of 15 mg/1 observed for the
example problem discussed above. The
different leaching patterns observed
with the two examples clearly demonstrate
the utility of mathematical simulation.
SUMMARY
The simulation of landfill leachate
migration using numerical models pro-
vides considerable insight into the
physical system. The importance of fluid
transport and hydrodynamic dispersion are
easily discernible from the numerical
results. The example transport problem
discussed in this paper further demon-
strates the influence of the hydrological
regime on the leaching pattern. While
the present example focused upon the large
scale picture, demonstrating its
utility as a tool for landfill location,
this type of simulation could also be
used to advantage in establishing an
optimal strategy in the landfill design
itself.
ACKNOWLEDGMENT
This work was supported, in part,
by funds obtained from the Solid and Hazard-
ous Waste Research Division, EPA MERL, Cin-
cinnati, OH, EPA Grant No. R803827-01.
REFERENCES
1. Amend, J.H., D.N. Contractor and
C. S. Desai, 1976. Oxygen depletion
and sulfate production in strip mine
spoil dams. J_n_ Numerical Hethods in
Geomechanics, C.S. Desai (ed), Vol.
II, 1155-116?.
2. Biggar, J.W. and D.R. Nielsen, 1976,
Spatial variability of the leaching
characteristics of a field soil.
Water Resour. Res., 12(1): 78-
82.
3. Kirda, C., D. R. Nielsen and J. W.
Biggar, 1973, Simultaneous transport
of chloride and water during in-
filtration, Soil Sci. Soc. Amer.
Proc, 37(3): 339-3^5-
k. Larson, N. M. and M. Reeves, 1976,
Analytical analysis of soil-moisture
and trace-contaminant transport.
Oak Ridge National Laboratory,
ORNL/NSF/EATC-12, Oak Rfdge, Tenn.
5. Finder, G. F., 1973, A Galerkin-finite
element simulation of groundwater con-
tamination on Long Island, New York,
Water Resour. Res., 9(6): 1657-1670.
6. Steelman, B., 1977, Calculation of
evapotranspirat ion on the South Fork
of Long Island. Research Report 77-WR-
2, Water Resources Program, Dept. of
Civil Engineering, Princeton
University, Princeton, N.J. OSS'tO.
7. Finder, G. F., W. P. Saukin, and
H. Th. van Genuchten, 1976. Use of
simulation for characterizing trans-
port in soils adjacent to land dis-
posal sites. Research Report 76-
WR-6, Water Resources Program, Dept.
of Civil Engineering, Princeton
University, Princeton, N.J. 08540
8. van Genuchten, M.Th., G. F. Pinder and
E. 0. Frind, 1977, Simulation of two-
dimensional contaminant transport
with isoparametric Hermit!an finite
elements, Water Resour. Res. (in
press).
9. Wood. A. L. and J. M. Davidson, 1975-
Fluometuron and water content distri-
bution : measured and calculated.
Soil Sci Soc Amer Proc., 39(5):
820-825.
103
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AERIAL DETECTION TECHNIQUES FOR LANDFILL POLLUTANTS
Warren R. Philipson and Dwight A. Sangrey
Cornell University
School of Civil and Environmental Engineering
Hollister Hall
Ithaca, New York 14853
ABSTRACT
A methodology for using remote sensing to detect landfill leachate contamination of
ground and surface water is described. The problem is addressed without regard to speci-
fic geographic or climatological regions.
Among the topics covered are leachate indicators, spatial and temporal aspects of
leachate detection, sensor selection, flight design and data interpretation. Specific
methodologies for using remote sensing to detect leachate under various situations are
outlined. These range from survey monitoring of individual landfills to comprehensive
programs for regulatory monitoring of many landfills.
INTRODUCTION
One major disadvantage of landfill
methods for solid waste disposal is the po-
tential production of leachate, an ex-
tremely variable liquid resulting from
waste decomposition and water flow through
the waste. If not controlled, leachate can
exit the landfill as part of, and as a con-
taminant of, the ground and surface water
regime.
For planning remedial measures to con-
trol leachate from an existing landfill,
all points of potential contamination must
be located. This task is difficult, time-
consuming and often inaccurate if conducted
solely through field surveys; especially,
since leachate breakout may occur at rela-
tively long distances from the landfill.
Although ground sampling and laboratory a-
nalysis are usually required to confirm
leachate contamination, remote sensing
techniques provide the most effective means
for detecting potential locations of lea-
chate breakout or contamination.
This paper provides a summary of a
report, "Detecting Landfill Leachate Con-
tamination Using Remote Sensors," which
the authors are preparing for the U.S. En-
vironmental Protection Agency (contract no.
68-03-2438). The work is an extension of
an earlier study by Sangrey Q2).
LEACHATE INDICATORS FOR SENSING
If leachate is to be detected directly
or indirectly with remotely sensed data,
then leachate or a leachate-related feature
musfe at the time of sensing, appear spec-
trally different from its surroundings or
have some unique or identifiable spatial
characteristic. The spectral and spatial
104
-------
indicators of leachate are listed in Table
1. They include observable features of
leachate itself—wetness or an anomalous
spectral response from water, soil, rock or
snow—and observable effects of leachate—
gaps in a vegetative or snow cover, or an
anomalous spectral response from grass or
taller vegetation. These indicators can be
examined from the standpoint of detection
with data acquired by airborne sensors of
electromagnetic radiation (Figure 1) .
ness or toxic substances can occur at long-
er distances from the landfill, 500 meters
being quite reasonable.
Gaps in a vegetative or snow cover are
usually easy to detect through sensing of
reflected solar radiation in the visible
and near-infrared spectral regions (Figure
2), of emitted radiation in the thermal in-
frared region, or of emitted or reflected
radiation in the microwave region (11), (10)
(8).
Multispectral scanners
IR
film
Active radar
Passive
microwave
Ordinary
film
Infrared
instruments
0.3/zm
15/u.m
Visible
XX
Ultraviolet
Infrared
1mm 10 cm Im
Millimeter
and
microwave
Scale variable
Figure 1. Electromagnetic Spectrum with Type of Sensors
(after Holter, 1971)
If large or small gaps in a vegetative
or snow cover can be related spatially to
a landfill, they often signal the presence
of leachate. Caused by the leachate's wet-
ness, toxicity or heat, the gaps can be i-
solated, or they can radiate from the land-
fill. Since heat would dissipate rather
quickly with distance, heat-caused gaps
should be found relatively close to the
landfill. In contrast, gaps caused by wet-
Since these gaps are not limited to leachate-
these gaps are not limited to leachate-
affected sites, the primary task is to re-
late the gap to the landfill. Topographic
and, to the extent possible, geologic anal-
yses are normally required.
Wetness
Similar to gaps, any damp, saturated
or puddled sites that can be related spa-
tially to a landfill are potentially con-
105
-------
u
o
o
£
<*-
4)
90r
80-
70-
60-
50
40
30
20
10
Snow
{Kondratyev, 1969)
30
Absorption
by water
(Kondratyev, 1969} ,
i
i
i
i
I
i
i
t
! \
Vegetation
(COSPERS, 1976)
20
10
E
u
c
fl>
'o
4)
O
O
C
o
c
a>
.3
.4 .5 .6 .7
Blue Green
Red
.8
Near infrared
.9
0
.0
Wavelength, //.m
Figure 2: Spectral Reflectance of Typical Vegetation,
Soil and Snow; and the Attenuation Coefficients of Water
106
-------
taminated by leachate. As with gaps, wet-
ness can radiate from the landfill or occur
in small or large isolated spots, or seeps,
the distance and direction from the land-
fill being highly variable.
Wetness can often be deduced from the
vegetative types. If not, its spectral
characteristics are sufficiently distinct
that wetness is usually detectable over the
entire electromagnetic spectrum (Bowers and
Hanks, (2); Blanchard et al. (1); Ulaby
et al. (15); Schmugge et al. (13). Al-
though damp sites will not present as
marked a contrast as saturated or puddled
sites, at least the wetter sites will be
separable.
Other Spectral Anomalies
Leachate will sometimes produce an a-
nomalous spectral response besides those
associated with wetness or gaps. Although
these spectral anomalies usually provide a
more positive indication of leachate than
gaps or wetness, they must still be trace-
able to the landfill.
The spectrally reflective anomalies
listed in Table 1 arise from possible dif-
ferences in reflectance between leachate
and soil, grass, snow or water, and between
leachate-stressed and unstressed vegeta-
tion. Because of its high ferric iron con-
tent, for example, leachate may exhibit an
unusually high red reflectance. Although
this is not unique to leachate, the re-
sponse contrasts sharply with that from
grass, snow or otherwise clear water, and,
to a lesser extent, with the response from
soil or rock.
In a similar manner, lipid coatings
on leachate-contaminated water should be
detectable through passive or active sen-
sing in the ultraviolet, blue, thermal or
microwave regions, or at various Fraunhofer
lines in, the visible region (Kennedy and
Wermund (6); Vizy (16); Watson et al.
(17). The spectral reflectance of posi-
tively or negatively stressed taller vege-
tation might also show anomalies at any
visible or near-infrared wavelength, though
the near-infrared reflectance-is apparently
more sensitive to a broader range of stres-
ses (COSPERS, 1976).
The spectrally emissive anomalies lis-
ted in Table 1 arise from the possible dif-
ferences in temperatures and/or emissivi-
ties between leachate and soil, with or
without grass; between leachate-affected
and unaffected water; and between leachate-
stressed and unstressed vegetation. Sen-
sing for spectrally emissive anomalies can
be performed in the thermal infrared or
microwave regions (Figure 1).
TEMPORAL ASPECTS OP LEACHATE DETECTION
Temporal factors must be considered in
a leachate detection program. This relates
to the value of monitoring the development
of the landfill from its initial stages to
the present, and to the effects of season
and time of day on the capacity to detect
leachate.
For many landfills, the prevailing
drainage conditions were established prior
to the development of the site, and they
have been changed little by the landfill
operation. In other cases, the landfill
operation has caused significant change at
the site proper, but has not affected the
subsurface drainage which surfaces at a
distance from the site. Seldom will the
development of the landfill alter the
drainage so completely that it will be
totally different from pre-landfill or, at
least, early landfill conditions. Conse-
quently, examination of remotely sensed
images (e.g., aerial photographs) of the
undeveloped and developing site will nor-
mally provide valuable information regard-
ing where to expect leachate.
Considering seasonal effects, it
should be obvious that since weather and
climate are the major determinants of the
amount of leachate produced, as well as the
amount of vegetation or snow present to
hinder detection, seasonal factors become
especially important. In general, the
potential for leachate production is high
during wet periods and low during dry or
107
-------
Table 1: Spectral and Spatial Indicators of Leachate
BACKGROUND/
SURROUNDINGS
GAP IN
COVER*
WETNESS*
ANOMALOUS SPECTRAL RESPONSE
REFLECTIVE
EMISSIVE
soil/rock with
grass cover
soil/rock with
little or no
grass cover
snow
water
taller vegetation
X
X
X
X
X
*A1though observable because of their spectral response, wetness and gaps
in a vegetative or snow cover are listed separately for ease of discussion. Wetness
ranges from damp areas to puddled water.
Table .2: Spectral Bands for Detecting- Leachate Through Reflected Radiation
Leachate Indicator Primary Secondary
Gaps
Vegetation/Soil, Rock
Snow/Soil/ Rock
Wetness
Soil
Soil with Grass
Spectral Anomalies
In Water
On Water (lipids)
On Soil
On Grass
Stressed Vegetation
Infrared, Red
Blue, Green
Infrared
Infrared
Red, Green
Ultraviolet
Red, Green
Red
Infrared
Red
Blue
Blue, Infrared
Infrared
Infrared, Green
Green, Red
108
-------
freezing periods. The potential for lea-
ch ate detection is normally lowest during
times With deep snow or full canopies of
taller vegetation.
Among other effects of season (and
latitude) are the shadows which may ob-
scure leachate indicators from overhead de-
tection. As is obvious, sun shadows are
also associated with the time of day. In
most instances, the high sun angles at mid-
day are best for detecting leachate indica-
tors through reflected radiation. Although
the water surface glint that accompanies
higher sun angles may obscure an anomalous
spectral response, it will, at least, fa-
cilitate the identification of wetness. In
contrast, sensing of emitted radiation
might best be performed during non-daylight
hours to enhance thermal differences (Myers
et al., (9).
RECOMMENDED PROCEDURES
Sensor Selection
The most useful wavelength intervals,
or spectral bands, for detecting leachate
indicators through reflected solar radia-
tion are listed in Table 2. For remote
detection of leachate, a sensor must pro-
vide data which allow an assessment of the
spatial relationships between leachate
indicators and the landfill under study.
This requirement can only be filled effec-
tively with an imaging sensor. Of the
available imaging sensors, still or panor-
amic film cameras and" scanning radiometers
("scanners") would be favored. The still
camera might be a single or multiple lens
frame camera, with any of several film-fil-
ter combinations. The scanner might be a
thermal infrared or multispectral sensor
(Table 3).
Although a multispectral scanner
could be applied successfully in place of
photographic camera systems, photographs
are less expensive to acquire, process and
analyze, and they are normally of higher
spatial resolution. If photographic sys-
tems have the spectral capacity to monitor
leachate in the ultraviolet, visible
and near-infrared regions, the unique data
acquirable by multispectral scanner are
limited to the infrared region, particu-
larly the thermal infrared. Since the
thermal data will be most valuable if ac-
quired during non-daylight hours, when
other possible multispectral scanner data
are not obtainable, a thermal infrared
scanner would normally be preferred to a
multispectral scanner with a thermal chan-
nel (Table 3).
Selection of a particular photographic
system is dependent upon the number and
types of landfills to be monitored, and
the availability of equipment, facilities
and/or funds. To illustrate, a local en-
vironmental group might wish to monitor a
single landfill. This group would likely
choose one photographic film for use with
a hand-held, 35 mm camera. A color infra-
red film would be more generally applicable
than other films (Tables 2 and 3). If
monitoring an inundated landfill, where
lipids might be expected, a black-and-
white film filtered to receive ultraviolet
and blue radiation should also be consi-
dered.
In contrast, a county environmental
or health agency might employ one or more
70mm or 13cm format cameras, loaded with
spectrally filtered, black-and-white films,
or with some combination of color and
black-and-white films; while a state moni-
toring agency might prefer the flexibility
of a four-lens multiband camera, as out-
lined in Table 3. The U.S. Environmental
Protection Agency, which has limited fa-
miliarity with the landfills and region to
be overflown, might allow for all spectral
and spatial indicators by carrying a 23cm
format camera, loaded with color infrared
film, and smaller format cameras, loaded
with other films (including one imaging
blue and ultraviolet radiation). Overall,
many combinations are possible and effec-
tive.
Thermal sensing for leachate is con-
sidered an optional extension of the pho-
tographic program. In general, thermal
data may: confirm or refute the interpre-
109
-------
Table 3: Photographic Camera and Scanner
Systems for Leachate Detection
SENSING OPTION
METHOD OF
SENSING
BANDS SENSED AND
RECORDED SEPARATELY
COMMENT
1. Photography
a. color film
single camera; B, G, and R* recorded as UV can be sensed if recorded with B**; con-
single image B, G, and R, respectively trast of B layer will be lowered; proper ex-
posure for UV and B will likely underexpose
GSR
b. color in- Idem G, R, and
frared film B, G, and
c . panchroma-
tic film
(black &
white)
Multilens cam- UV, B, G,
era or several corded as
cameras, with
spectral filters;
multiple images
IR recorded as UV and B cannot be sensed without affecting
R respectively G, R, and IR
and R, each re- Lower contrast of UV image will not affect
black & white other spectral images
d. black & Idem
white infra-
red film
UV, B, G, R, and IR,
each recorded as black
S white
Most multilens cameras have 4 lenses; lower
contrast of UV image will not affect other
spectral images
2. Multispectral Single scanner; Any reflected or emitted Analog or digital data for any band or corn-
magnetic tape, bands from UV, visible bination of bands can be printed on paper,
displayed on video, or converted to photo-
graphic film
scanner
with or with-
out image of
one band off
cathode ray
tube or simi-
lar monitor
fi IR, including thermal;
each band recorded as
digital or analog signal
on tape,- if recorded in
aircraft, one band as black
& white film
3. Thermal scan-
ner
Single scanner; Commonly 8-14ym and/or Idem, if recorded on tape
magnetic tape 3-5ym; recorded as digital
and/or image or analog signal on tape,
of one band or as black & white film
off cathode ray
tube or similar
monitor
*B-Blue, G-Green, R-Red, IR-Infrared, UV-Ultraviolet
**Sensing of ultraviolet radiation will be limited by glass lens to wavelengths longer than about
0.36pm.
-------
tation of a photo-identified indicator;
provide some indication of the status of
leachate contamination (e.g., if it is hot,
a wet area is likely contaminated); detect
other indicators which were overlooked or
undetectable with photographic systems; or
provide no additional information.
Flight Parameters
The design of an aircraft mission for
detecting leachate is governed largely by
the sensor(s) utilized and the spatial,
spectral and temporal characteristics of
leachate. The seasonal and diurnal charac-
teristics of the indicators, as well as the
local weather, set limits on the optimum
time for sensing (Table 4).
ger. A 1:5,000 scale photograph could be
obtained with a 150mm focal length camera
by flying at 750 meters above ground, while
shorter focal length cameras would require
lower flying heights; H = 5,000 (f), where
H = flight height in meters, and f = focal
length in meters.
As regards flight parameters for thermal
sensing, it is notable that the temperature
of leachate near a landfill may be several
degrees Celsius higher than uncontaminated
waters in the vicinity. Thermal infrared
scanners can detect apparent temperature
differences of less than a degree (Reeves,
1975). While numerous factors must be con-
sidered in designing a thermal scanner mis-
sion, it is likely that the design flight
Table 4: The Potential for Detecting Leachate under Different Vegetative and
Seasonal Conditions
VEGETATIVE COVER
SEASONAL
CONDITIONS
Wet
Dry or
Frozen
Partial
or Light
Snow
Full or
Heavy Snow
MODE OF
SENSING
photo
thermal
photo
thermal
photo
thermal
photo
thermal
NONE
E*
E-G
E-G
E
F
E
F-P
G
GRASS
E
E-G
G
E
F
E
F-P
G
PARTIAL
CANOPY
G-F
F
F
G
F
G
P
G-F
FULL
CANOPY
F-P
P
P
P
P
P
P
P
*Ratings of Excellent (E), Good (G), Fair (F), and Poor (P) are subjective for midday
photographic or pre-dawn thermal sensing. The two ratings are not equivalent.
For a given sensor, the size and/or
spectral response of leachate indicators,
and the size of the leachate-affected area,
set limits on the flight height. For ex-
ample, leachate-related gaps and wetness
are quite variable in size; yet most lea-
chate problems would be discovered if the
photographic sensing could detect gaps and
wetness of one meter across. If one-meter
gaps and wet spots were spectrally dis-
tinct, they should be detectable with pho-
tographic scales of about 1:5,000 or lar-
height should be no more than 1,000 meters
above ground for detecting a thermal lea-
chate target. The mission should be con-
ducted during pre-dawn hours as outlined
in Table 4.
Data Analysis
The specific technique(s) applied in an-
alyzing remotely sensed data for leachate
indicators are dependent upon the form of
remotely sensed data and the available
in
-------
equipment, time and/or funds for analysis.
More sophisticated or costly analysis tech-
niques are not synonymous with more infor-
mation. Whatever the approach to analysis,
the results must be applicable in the
field; suspected sites of leachate must be
located in the field, via maps or photo-
graphs, as well as in or on the analyzed
data.
Several forms of data might be avail-
able for analysis: (1) panchromatic con-
tact prints, (2) black-and-white trans-
parencies of different visible and near-
infrared spectral bands, (3) color and/or
color infrared transparencies, {4} black-
and-white transparencies of one or two
thermal bands, and (5) magnetic tape con-
taining digital or analog thermal data.
In general, the analysis may be visual,
aided by magnification, stereoscopic view-
ing or filters, or the analysis may involve
color enhancements through density slicing,
additive-color viewing or subtractive-color
viewing with diazo (Simonett, 0.41, Reeves
(11). Densitometric measurements could
provide quantitative values for selected
features, but digitizing the image data is
likely to be uneconomical and unwarranted.
DETECTION METHODOLOGY
The specific objective of a remote
sensing program will determine the most
appropriate detection methodology. Two
cases can be defined. One is typical of
regulatory monitoring where a general sur-
vey of a large number of waste disposal
sites is conducted to evaluate conformance
to regulations. The major elements in this
type of methodology are:
Step 1. Obtain topographic maps which
locate landfills to be monitored.
Step 2. Fly 1:5,000 scale, aerial
photographic coverage of each landfill
using film-filter combinations which record
ultraviolet, blue, green, red, and near-in-
frared radiation.
Alternative A
Step 3A. Analyze photographs to iden-
tify the most probable locations of lea-
chate breakout or contamination.
Step 4A. Field check these most pro-
bable locations.
Step 5A. Take appropriate action
based on verification of leachate contamin-
ation .
Alternative B
Step 3B. Fly pre-dawn thermal infra-
red scanner coverage of all landfills.
Step 4B. Analyze thermal and photo-
graphic data.
Step 5B. (See Step 4A).
Step 6B. (See Step 5A).
Alternative G
Step 3C. (See Step 3A).
Step 4C. Based on the photographic
analysis, select landfills to be overflown
with pre-dawn thermal infrared scanner co-
verage. Conduct this sensing at a dry or
frozen, low vegetation period to maximize
effectiveness of this sensor.
Step 5C. (See Step 4A).
Step 6C. (See Step 5A).
The second general type of detection
methodology applies to comprehensive con-
trol monitoring. The major elements in
this type of monitoring are:
Step 1. Obtain all available back-
ground information on the landfill site,
including topographic, soil and geologic
maps and reports.
Step 2. Obtain aerial coverage of the
undeveloped landfill site and coverage ac-
quired periodically during the development
112
-------
of the site.
REFERENCES
Step 3. Analyze available aerial cov-
erage, together with background information,
to identify the most probable locations of
leachate breakout or contamination.
Step 4. Field check the landfill
site(s), concentrating on those locations
identified in Step 3.
Step 5. Fly new aerial photographic
coverage of the landfills using one or more
film-filter combinations which are appro-
priate for the expected spectral leachate
indicators.
Step 6. Analyze the new photographs,
together with the other aerial and back-
ground data, to identify the most probable
locations of leachate breakout or contamin-
ation.
Step 7. Field check the landfill
site(s).
Step 8. Upon verification of leachate
contamination, plan remedial measures.
(Steps 9 through 12 are optional extensions)
Step 9. Fly pre-dawn, thermal infra-
red coverage of the landfills.
Step 10. Analyze the thermal infrared
data, together will all photographic and
background data, to identify any additional
locations of suspected leachate breakout or
contamination.
Step 11. Field check any new locations
of suspected leachate.
Step 12. If required, modify planned
remedial measures.
ACKNOWLEDGMENTS
Support for the field work reported in
this project was provided by the New York
State Department of Environmental Conserva-
tion (Contract C-79273) and the NASA-spon-
sored Remote Sensing Program at Cornell
(Grant NGL 33-010-171). Remote sensing
missions were supported by EPA/EPIC.
Preliminary analysis of these data
was done by W. L. Teng under the direction
of Professor T. Liang from the School of
Civil and Environmental Engineering at
Cornell University.
1. Blanchard, M. B., R. Greeley and R.
Goettelman. 1974. Use of visible,
Near-Infrared and Thermal Infrared Re-
mote Sensing to Study Soil Moisture.
p. 693-700. In_ Proc. 9th Int'l. Symp.
on Remote Sensing of Environ. Held at
Univ. of Mich. Environ. Research Inst.
of Mich., Ann Arbor, Mich.
2. Bowers, S. A. and R. J. Hanks. 1965.
Reflection of Radiant Energy from Soils.
Soil Science 100:2:130-138.
3. Committee on Remote Sensing Programs
for Earth Resource Surveys. 1976. Re-
source and Environmental Surveys from
Space with the Thematic Mapper in the
1980's. National Academy of Sciences,
Washington, D.C. 122 pp.
4. Condit, H. R. 1970. The Spectral Re-
flectance of American Soils. Photo-
grammetric Eng'g. 36:9:955-966.
5. Holter, M. R. 1971. The Interpretation
of Spectral Data. p. 305-325. In
Int'l. Workshop on Earth Resources Sur-
vey Systems. Held at Univ. of Mich.
NASA SP-283. Nat'l. Aeronautics &
Space Admin., Washington, D.C.
6. Kennedy, J. M. and E. G. Wermund.
1971. Oil Spills, IR and Microwave.
Photogrammetric Eng'g. 37:12:1235-
1242.
7. Kondratyev, K. Ya. 1969. Radiation in
the Atmosphere. Academic Press, N.Y.
912 pp.
8. Matthews, R. E., (Editor). 1975. Ac-
tive Microwave Workshop Report. NASA
SP-376. Nat'l. Aeronautics and Space
Administration, Washington,D-C. 502 pp.
9. Myers, V. I., M. D. Heilman, R. J. Lyon,
L. N. Namken, D. Simonett, J. R. Thomas,
C. L. Wiegand and J. T. Woolley. 1970.
Soil, Water, and Plant Relations, p.
253-279. In_ Remote Sensing; With
Special Reference to Agriculture and
Forestry. National Academy of Sciences,
Washington, D.C.
10. Rango, A. (Editor). 1975. Operational
Applications of Satellite Snow-Cover
Observations. Proc. of Workshop held
in South Lake Tahoe, Calif. NASA SP-39L
113
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Nat'l. Aeronautics and Space Admin.,
Washington, D.C. 430 pp.
11. Reeves, R. G. (Editor). 1975. Manual
of Remote Sensing. 2 vols. Amer. Soc.
Photogramtnetry, Falls Church, Va. 2047
pp.
12. Sangrey, D. A., W. L. Teng, W. R.
Philipson and T. Liang. 1976. Remote
Sensing of Ground and Surface Water
Contamination by Leachate from Land-
fill. Paper 15-1. In_ Proc. Int'l.
Conf. Environmental Sensing and Assess-
ment. Held Sept. 1975, Las Vegas.
Inst. Electrical 6 Electronics Engin-
eers, New York.
13. Schmugge, T., T. Wilheit, W. Webster,
Jr., and P. Gloersen. 1976. Remote
Sensing of Soil Moisture with Micro-
wave Radiometers—II. NASA Technical
Note D-8321. Nat'l. Aeronautics fi
Space Admin., Washington, D.C. 34 pp.
14. Simonett, D. S. 1974. Quantitative
Data Extraction and Analysis of Remote
Sensor Images, p. 51-82. ln_ Remote
Sensing: Techniques for Environmental
Analysis. (Estes, J. E. and L. W.
Senger, Editors). Hamilton Press,
Santa Barbara, Calif.
15. UJLaby, P. T., J. Cihlar and R. K.
Moore. 1974. Active Microwave Mea-
surement of Soil Water Content;. Remote
Sensing of Environment 3:185-203.
16. Vizy, K. N. 1974. Detecting and Moni-
toring Oil Slicks with Aerial Photos.
Photogrammetric Eng'g. 40:6:697-708.
17. Watson, R. D., W. R. Hemphill and R. C.
Bigelow. 1975. Remote Sensing of
Luminescing Environmental Pollutants
Using a Fraunhofer Line Discriminator
(FLD). p. 203-222. In Proc. 10th
Int'l. Symp. on Remote Sensing of
Environ. Held at Univ. of Mich.
Environ. Research Inst. of Mich., Ann
Arbor, Mich.
114
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POLLUTANT MIGRATION PATTERNS FROM LANDFILLS
Jerome L. Mahloch, B. L. Folsom, Jr., J. M. Brannon,
J. D. Broughton, and J. H. Shamberger
U. S. Army Engineer Waterways Experiment Station
Vicksburg, Mississippi
ABSTRACT
A survey of three municipal landfill sites was conducted under the sponsorship of the
U. S. Environmental Protection Agency. The objective of the survey was to identify con-
taminants and determine their distribution in the soil and groundwater beneath the landfill
sites. Three sites were selected for the study and the sites represented varying geologic
conditions, recharge rates, and age-, ranging from a site that had been closed for 15 years
to a site currently operating.
Site investigations included a preliminary geologic investigation to establish boring
locations. Generally, seven to nine borings were made in the sites and were distributed
up-gradient and down-gradient with respect to groundwater contours, and within the site.
Soil cores were removed from a boring at varying locations depending on the .distance from
the bottoms of the landfill to groundwater. Undisturbed samples were obtained for soil
properties determination and disturbed samples were obtained for chemical analysis.
A groundwater sample was obtained from each boring location.
Soil properties examined included permeability, density, water content, and grain
size analysis. Chemical analysis of the soil samples included a water and acid extract of
soil samples. Filtered water extract samples were analyzed for 23 chemical parameters, and
filtered acid extract samples were analyzed for 12 trace metals. Groundwater samples were
analyzed for the 23 parameters used for the water leach.
Presentation of the results of the site survey will include the soil properties tests
and an analysis of the chemical properties for general trends. Emphasis will be placed
on comparing and contrasting the sites studied.
INTRODUCTION
Ultimate disposal of municipal solid
wastes by landfilling accounts for the
disposition of a majority of the solid
waste produced in this country (1). In
many areas of the country, net recharge
of groundwater aquifers 'occurs and
represents a potential pathway for con-
taminant migration from the solid waste
to these aquifers. Because the net turn-
over time for groundwater aquifers is
extremely long, as compared to surface
water supplies, it is critical that these
sources of water be protected from contami-
nation via solid waste disposal.
Municipal solid waste disposal by
sanitary landfills usually incorporates a
number of design considerations to reduce
the risk of contaminant migration. The
most important of these include proper site
selection, preparation, and disposal
operation. In many cases, a minimum
115
-------
distance between the refuse and groundwater
is required to take advantage of filtration,
dispersion, and attenuation within the soil
matrix if leaching does occur. Investiga-
tions in the past concerning contaminant
migration from landfill have primarily con-
centrated on either monitoring programs
examining the input to groundwater
aquifers (2) or investigations of soils
and attenuation associated with landfill
sites (3). These studies seek to provide
information that can be used to strengthen
current design and operational guidelines,
thus minimizing the threat of groundwater
contamination from municipal solid waste
disposal.
The study described herein is a survey
of three landfill sites in the Eastern
United States. The sites represented
varying geologic conditions, recharge rates,
age (ranging from a site closed for 15 years
to a currently operating site), and dis-
tances between refuse and groundwater,
ranging from 2-20 meters. The objective of
the study was to characterize the soil and
groundwater beneath and in the immediate
vicinity of the landfill to identify and
determine the distribution of contaminants
associated with the landfill sites. Primary
emphasis was placed on trace metals, the
influence of soil extraction method for
determining availability, and physical
characteristics of soils from the respective
site as they influence contaminant
distribution.
METHODS
Site Selection
Sites for inclusion within the study
were selected from a list of available sites
considering the variables mentioned
previously. Preliminary evaluation was
based on geologic information available,
including groundwater hydrology, and
previous records or studies performed on
the sites. The three sites selected
represent a diverse group based on geologic
conditions, age, and depth to groundwater.
Site Sampling
Based on preliminary information
available, a sampling plan was prepared for
each site. In general, this sampling plan
included a combination of borings both
within the site (internal) and around
the site (external). External borings were
arranged in such a manner that a portion of
these borings were upgradient and a portion
were downgradient with respect to ground-
water flow at the site. A generalized
boring location scheme is presented in
Figure 1.
DIRECTION OF
GROUNDWATER FLOW
Figure 1. Generalized Sampling Plan.
Sampling from individual borings
included sets of companion samples. These
companion samples represented undisturbed
samples for soil analysis and disturbed
samples for chemical analysis. Borings
were made with truck-mounted rotary drill
using a hollow stem flight auger. Samples
were taken with a Hvorslev fixed-piston
sampler in a Shelby tube or a split-spoon
sampler.
Vertical sampling within borings was
arranged depending on the-distance between
the refuse and groundwater (zone of
saturation). The first sample was taken
at the refuse-soil interface and the last
sample was taken at (or just above) the
zone of saturation. Three to seven samples
were taken at a particular boring dependent
on the distance between the refuse and
groundwater. A groundwater sample was
obtained with a bailer 48 hours after the
boring was made. A generalized vertical
boring profile is presented in Figure 2.
To maintain consistency between borings,
samples were taken at approximately the
same elevations between borings.
116
-------
§ 4
oJ
2
SOIL COVER
MUNICIPAL REFUSE
OR
NATURAL SOIL
UNDISTURBED-
) DISTURBED —
NATURAL SOIL
-SOIL PROPERTIES
-CHEMICAL PROPERTIES
ZONE OF SATURATION
*- GROUNDKATERSAMPLE-
"CHEMICAL
PROPERTIES
Figure 2. Vertical Boring Profile.
Sample Analysis
Soil Properties. Undisturbed soil
samples were analyzed for the following
properties: (1) Grain size analysis, (2)
Atterberg limits, (3) Dry density, (4) Wet
density, and (5) Permeability. These
properties allowed classification of
individual samples by the USCS system (4).
Chemical Properties. Chemical analysis
of soil samples were performed by making
either a water or acid extraction of samples
as received from the field. Moisture
contents were determined on sub-samples to
permit calculation of constituent concen-
trations on an oven-dry weight basis. Water
extracts and processed groundwater samples
were preserved by the appropriate
methods (5). A list of the chemical
species determined in the extracts or
groundwater samples is presented in Table 1.
Water Extraction. Two hundred
grams of soil of known moisture content were
weighed into 1000-ml polycarbonate centri-
fuge bottles, 600 ml distilled-deionized
water added, the bottles sealed, and then
shaken on a rotary shaker for one hour.
After shaking, the bottles were centrifuged
at 2200 rpm for 30 minutes and the super-
natant was filtered through a 0.45-ym
millipore filter.
TABLE 1
LIST OF CHEMICAL PARAMETERS
CHEMICAL SPECIES GROUNDWATER EXTRACT
FILTRATE WATER NITRIC ACID
S04
so.
Cl
N03
N02
TOC
Mg
Ca
Na
CN
As
Be
Cd
Cr
CL
Mn
Pb
Zrt
B
Se
Hg
X
X
X
X
X.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Acid Extraction. Fifty grams of
wet soil of known moisture content were
weighed into 250-ml teflon beakers, and
60 ml of 8!N nitric acid (HNO ) were added.
The soil-acid suspensions were heated to
95°C for 45 minutes and stirred every 15
minutes. After being allowed to cool to
room temperature, the suspensions were
transferred and filtered with 8N HN03
through a 0.45-ym filter. The digested
soil was washed three times with 20-ml
portions of 8N^ HNC^. The filtrate was
transferred to 250-ml volumetric flasks
and diluted to volume with 8N HN03-
Groundwater Samples. Upon
arrival at the laboratory, the groundwater
samples were centrifuged at 2200 rpm for
30 minutes. The resulting supernatant
was then filtered through a 0.45-ptn
millipore filter and preserved for
chemical analysis.
Data Analysis
To facilitate subsequent data
analysis, the results of chemical analysis
were appropriately coded, and the sample
coordinates were appended. Horizontal
coordinates were calculated from a
reference point at each site and the
117
-------
vertical coordinate was determined from
the boring log.
Analysis of the resultant data was
performed by use of multivariate statistical
techniques. These techniques are particu-
larly advantageous for this type of study
since they seek to reduce the variable set
to some interpretable grouping of variables.
Relationships among the sites were
determined by factor analysis (6) on the
following groups of chemical analyses:
(1) groundwater plus water extracts, (2)
water extracts, and (3) acid extracts.
Variables (i.e., chemical species) that
demonstrated no variance for a particular
site (e.g., samples were consistently below
detection limits) were deleted from the
data matrix prior to analysis. Relation-
ships between sites were explored by means
of discriminant analysis (7). As in the
case of factor analysis, variables that
possessed no variance between sites were
eliminated from the data matrix prior to
analysis.
The underlying principle behind both
factor analysis and discriminant analysis
is to construct factors that are linear
combinations of the original data set. In
the case of factor analysis, this is
aimed at maximizing the variance of the
original data accounted for by as few
factors as possible. In the case of
discriminant analysis, this is aimed at
explaining the separation of data sets by
as few factors as possible. In both types
of analysis, the use is generally
exploratory in nature; that is, attempting
to reduce the number of variables required
to explain behavior of the data.
RESULTS AND DISCUSSION
General Site Characteristics and Soil
Properties
The results of tests on soil proper-
ties are presented as a range of values
for the respective sites in Table 2. As
is evident from this information, the
three sets varied significantly with
respect to geologic properties. This
variation was expected to influence the
results and interpretation of the chemical
analysis.
The elevation data show the thickness
of refuse and the relationship of the
refuse to the groundwater. In terms of
refuse thickness, the sites are related as
C > A >_ B; in terms of distance to ground-
water the sites are related as A > C >_ B.
Since it was relatively difficult to
determine the exact elevation of the
refuse-soil interface, the elevations
presented in Table 2 may not be exact but
relationships between sites are probably
accurate. USGS soil types exhibited by
the three sites indicate gradations in
which A, > C > B,'water contents and
densities generally reflect the soil
classification and geological setting of
the respective sites. Permeabilities
generally fell within values that would
be expected from the soils at the sites
although sites B and C demonstrated a wide
range of values. Permeability and soil
characteristics are extremely important
in relationship to attenuation capacity
of the respective sites. Based on these
characteristics, the expected attenuation
in the soil at the sites would be ranked
as B > C > A. Little or no contaminant
attenuation by the soil would be expected
at Site A.
In addition to the geological and
physical properties of the sites, an attempt
was made to characterize the refuse at the
various sites. Based on historical records
available from each site surveyed, the age
or the sites were ranked as A > B >. G.
In the case of site C, the facility was
operating as a sanitary landfill at the
time of the survey.
Chemical Characteristics
The procedures utilized for analyzing
the chemical data from the samples were
selected to condense the data and reduce
the number of variables to be considered.
The results of the factor analysis were
displayed by plotting the factor scores
obtained for. the first two factors. The
scores are computed to have a mean of 50.0
and standard deviation of 10.0 for each
factor. The explained variance is noted
for each plot and the major variables
contributing to each factor are displayed
along the respective axes. A similar
procedure was used to display the results
of the discriminant analysis conducted
on the data from all sites. For purposes
of clarity, the chemical data from the
water extract samples plus groundwater
and acid extract samples were treated
separately.
118
-------
SITE
A
TABLE 2
SITE GEOLOGY AND PHYSICAL PROPERTIES OF SOILS
GEOLOGICAL
SETTING
GLACIAL
TERRACE
AEOLIAN
LOESS
RESIDUAL SILTS
AND CLAYS
REFUSE
258-259
52- 67
145-157
ELEVATION
meters
NATURAL SOIL
254-256
49- 64
122-132
GROUNDWATER
231-232
50- 61
122-132
uses
SOIL
TYPE
SP
ML.CL
SM.ML
WATER
CONTENT
*
2.4- 7.5
20.1-33.3
14.9-28.9
DENSITY
tmi cm"'
1.51-1.78
1.40-1.57
1.52 -;.78
PERMEABILITY
cm sec
2.0xlO'!
l.OxlO'1
8.0x10°
8.0xlO-b
3.0x10-'
3.0x10''
Water Extracts. The water extracts
performed on the soil samples were intended
to demonstrate: (1) if water soluble con-
taminants originating from the refuse had
migrated into the natural soil (or ground-
water), and (2) if water soluble contam-
inants had been removed from the soil
underlying the landfill sites. In the
case of the water extract samples factored
for site B, no demonstrable differences
could be detected within the sample set;
therefore, this site was not considered
under this section, except for the results
of the discriminant analysis.
The results of factoring the water
extracts and groundwater data for sites A
and C are presented in Figures 3 and 4,
respectively. For site A, there is a
. LEGEND
0 WATER LEACH
• GROUNDWATER
EXPLAINED VARIANC£ = 95X
so
'
40 50
FACTOR-I, [Cl, Cn]
Figure 3. Factor Analysis, Site A:
Water Extracts Plus Groundwater
LEGEND
O WATER ttACH
• GROUNOWATER
EXPLAINED VARIANCES*
KOTE * tj KITHIN ZONE Of SATURATION
Figure 4.
FACTOR-I, [tin, U|, C«-l]
Factor Analysis, Site C:
Water Extracts Plus Groundwater
significant separation between groundwater
and water extract samples. In the case of
the first factor, Figure 3, all water
extract samples appeared to possess higher
levels of chloride and cyanide than the
groundwater samples. Because there is
little separation between water extract
samples, separation for factor I represents
background conditions. In contrast, there
is significant separation between ground-
water samples on factor II, representing
magnesium and calcium. Furthermore, the
points in the lower left quadrant represent
up-gradient groundwater samples taken down-
gradient and beneath the landfill. This
would indicate that calcium and magnesium
have been introduced into the aquifer as a
result of leaching from the landfill. In
the case of site C, a separation between
several points representing groundwater
samples and water extract samples within
the zone of saturation is evident,
Figure 4. Separation is significant for
both factors obtained. The three points to
the extreme right in Figure 4 represent
samples obtained down-gradient from the
119
-------
landfill. Similar to site A, this indicates
that certain contaminants have been intro-
duced into the aquifer as a result of
leaching.
The results of factoring the water
extract samples for sites A and C are
presented in Figures 5 and 6, respectively.
CXPlAINCO VARIANCE «99X
LEGEND
O INTERNAL
• EIIERNAl
FACTM-llCI.Cii]
re" ~ ~ it,
Figure 5. Factor Analysis, Site A:
Water Extracts
internal points on factor II except for one
point that may be an outlier. In contrast
there is significant separation between
internal and external points for site C.
Factor I is represented by nickel and
arsenic (inverse relationship), and
factor II is represented by calcium. These
data indicate that arsenic has originated
from the landfill, and apparent leaching
of naturally occurring nickel and calcium
from the soil. The leaching of calcium
from underlying soils has been previously
demonstrated and shown to be related to the
migration of leachate from a landfill (8,9).
The data from the water extract
samples for all sites were analyzed by
discriminant analysis, and the results are
presented in Figure 7. Similar to factor
LECEND
O INTERNAL
• EXTERNAL
EKPIA!N!D URIAHCE
LEGEND
O , HURNAL
• EKTtHMA.
Figure 6. Factor Analysis, Site C:
Water Extracts
For site A there exists some separation
between internal and external samples on
factor I, Figure 5. This factor is
similar to factor I previously obtained
for site A, Figure 3. This may indicate
that chloride and cyanide are being
introduced into the underlying soil by
leaching. Due to the high permeability
of soils beneath site A, this condition may
be expected to occur. There is no
significant separation of external and
Figure 7.
Of-I. [NI]
Discriminant Analysis, All Sites:
Water Extracts
analysis, major variables contributing to
separation between data sets are noted on
the respective axes. A distinct separation
exists between sites A and C and site B on
the discriminant factor I, sodium. This
separation is explained primarily by
differences in chemistry and soil
mineralogy between the respective sites.
In contract, the separation on factor II
is between internal and external samples as
opposed to site location. In terms of
arsenic, this implies movement of this
element from the landfill to the underlying
soil. In the case of the remaining
elements (calcium, magnesium, nickel, and
lead), an inverse relationship exists
indicating the leaching of these elements
from the underlying soils due to the
presence of the landfill. Because of the
age of two of the sites (i.e., A and B),
this leaching may not be detected in
groundwater samples taken at the time of
120
-------
the site survey.
Acid Extracts. The acid extract
performed on the samples was intended to
dissolve or bring into solution all but
certain mineral structures of the
samples (10). In this manner, comparisons
could be made between internal and external
samples to determine the extent of
attenuation that had occurred (11). The
results of factoring and acid extract
data for sites, A, B, and C are presented
in Figures 8-10, respectively. In the
EXPLAINED VA«IANC£'«2X
LEGEND
O INTERNAL.
• EXTERNAL
'
«0 ' 50
FACTOR-LlZ", N,J
EXPLAINED VARIANCE* 83%
LEGEND
O INTERNAL
* EXTERNAL
Vs.. .
40 SO 60
FACIOB-I. [Hi. Cu. Cf)
Figure 8. Factor Analysis, Site A:
Acid Extracts
EXPLAINED VARIANCE-*}*
LEGEND
O INTERNAL
• EXTERNAL
FACTOR-!. {El. Cu]
Figure 9. Factor Analysis, Site B:
Acid Extracts
Figure 10. Factor Analysis, Site C:
Acid Extracts
case of site A. both internal and external
points demonstrate a large variability.
Because of the physical and geological
characteristics of this site, this
variability may be expected. No definite
conclusion with respect to attenuation may
be reached from this analysis of data on
site A. For site B, some separation of
external and internal sample points was
evident, Figure 9, for both factors
indicating that some degree of attenuation
had occurred in the soil beneath the site.
Because of the low permeability generally
exhibited at site B, the separation of
points (i.e., degree of attenuation) was
not too significant with samples obtained
from various depths beneath the landfill.
The results of factoring for site C,
Figure 10, does demonstrate a significant
amount of attenuation as evidenced by the
separation between internal and external
points. Separation appears to be most
significant for factor I, zinc and nickel.
It is interesting to note that the
evaluation of data for site C appears to
contradict the evaluation based on the
water extract samples. Examination of the
factors related to nickel appear to
indicate leaching in the case of the water
extract samples but attenuation in the
case of acid extract samples. This
anomaly may possibly be explained by a
conversion of water soluble nickel com-
pounds in the soil under site C to more
insoluble forms by the presence of the
landfill.
The results of the acid leach data
are summarized for all sites through
discriminant analysis and are presented
in Figure 11. Evaluation is similar to the
121
-------
LEGEND
•*••;•,!
Figure 11.
'!.Cr.C,l]
Discriminant Analysis, All
Sites: Acid Extracts.
case for water leached samples performed
previously. Separation on factor I appears
to be solely dependent on the site
selected, while separation on factor II
is a function of sample location within a
site. The presence of arsenic and its
attenuation, alluded to earlier, are
confirmed in Figure 11. The conversion
of nickel to a more insoluble form is
confirmed by a comparison of Figures 7 and
11. These conclusions seem to hold for all
sites with the exception of A. In this
case, the opposite effect appears to have
occurred.
Summary of Chemical Properties
The leaching of contaminants from
landfills into subsurface soils and
aquifers occurs at municipal landfill
sites. Additionally, the leachate may
react with certain elements in the sub-
surface soil and cause their subsequent
migration. These events are dependent on
site conditions although evidence for
both addition and removal of contaminants
was found in this study. Certain con-
taminants, once mobilized through leaching,
may become attenuated in the subsurface soil
and continued leaching may convert some
contaminants to forms that are water
insoluble and more resistant to leaching.
The data analysis presented in this
paper does have validity in interpreting
and summarizing the results from this site
survey. Since the derived factors in this
study represent combinations of original
variables, the behavior inferred may hold
for groups of contaminants represented by
the various factors. Application of these
techniques to related studies may reveal
information concerning the migration or
behavior of various contaminants that
may be useful in designing monitoring
programs for municipal sanitary landfills.
REFERENCES
1. Apgor, M. A. and Langrauir, D., "Ground-
water Pollution Potential of a Landfill
Above the Water Table," National Groundwater
Quality Symposium, Denver, Colorado, 1971.
2. Kunkle, G. R. and J. W. Shade,
"Monitoring" Ground-Water Quality near a
Sanitary Landfill," Groundwater, 14: (1)
11-20, 1976.
3. Suarez, D. L. and D. Langmuir, "Heavy
Metal Relationships in a Pennsylvania
Soil," Geochimica and Cosmochimica Acta,
4£: 589-598, 1976.
4. Laboratory Soils Testing, Engineer
Manual 1110-2-1906, U.S. Army Office,
Chief of Engineers, Washington, D.C., 1972.
5. Methods for Chemical Analysis of Water
and Wastes, U.S. Environmental Protection
Agency, Report No. EPA-625/6-74-003, 1974.
6. Kaiser, H. F., "A Second Generation
Little Jiffy," Psychometrika, 35: (4)
401-415, 1970.
7. Cooley, W. W. and P. R. Lohnes,
Multivariate Data Analysis, John Wiley and
Sons, New York, NY 1971.
8. Griffin, R. A. et al., "Attenuation of
Pollutants in Municipal Landfill Leachate
by Clay Minerals," Environmental Geology
Notes, No. 78, Illinois State Geological
Survey, Urbana, Illinois, 1976.
9. Rovers, F. A., H. Mooij, and
G. J. Farquhar, "Contaminant Attenuation -
Dispersed Soil Studies," Proceedings of the
Hazardous Waste Research Symposium,
Tucson, Arizona, 1976.
10. Carmody, D. J., J. B. Pearce, and
W. E. Yasso, "New York Bight," Marine
Pollution Bulletin, 4_: 132-135, 1973.
11. Korte, N.E., W. H. Fuller, E. E. Niebla,
J. Skopp, and B. A. Alesii, "Trace Element
Migration in Soils: Desorption of
Attenuated Ions and Effects of Solution
Flux," Proceedings of the Hazardous Waste
Research Symposium, Tucson, Arizona, 1976.
122
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LAND DISPOSAL CRITERIA AND COMPLIANCE MONITORING
RELATIVE TO LEACHATE AND GROUND WATER
Kenneth A. Shuster
Office of Solid Waste
U.S. Environmental Protection Agency
Washington, D. C. 20460
I am working on the solid waste
disposal regulations to be promulgated
by EPA under authority of Section
4004(a) of the Resource Conservation
and Recovery Act of 1976 (PL 94-580).
These regulations are to contain cri-
teria for determining which solid waste
disposal facilities shall be classified
as sanitary landfills and which shall
be classified as open dumps. Such
criteria are to provide that a facility
may be classified as a sanitary land-
fill and not an open dump only if there
is no reasonable probability of adverse
effects on health or the environment
from disposal of solid waste at such
facility. The regulations may provide
for the classification of the types
of sanitary landfills. Under Sections
4003, 4004, and 4005, open dumps are
prohibited in the United States.
Existing sites must be either closed
or upgraded, and all new sites must be
sanitary landfills. Implicit in such
criteria is that a reasonable monitor-
ing scheme exist to determine compliance.
The criteria will probably address
such impacts as air pollution, surface
water contamination, safety, vectors,
bird hazards, methane migration hazards,
and ground water contamination. A
particularly difficult problem area,
and subject of this paper, is criteria
for ground water. The development of
ground water criteria must draw upon
the results of research, as being
reported at this symposium, and the
best thinking of ground' water, landfill,
attenuation, and leachate experts,
many of whom are gathered here today.
Leachate, when generated, must
go somewhere. Sometimes it seeps into
surface waters where it is usually
rapidly diluted and dissipated. In
stagnant, slow moving, or low volume
waters, however, leachate may have a
significant impact. Our leachate
damage assessment study identified 47
cases of leachate-related fishkills in
20 states from 1963 to 1974 involving
over 65 miles of streams and 42 acres
of lakes and killing at least 215,000
fish. Surface seeps of leachate,
however, can be rather easily prevented
or corrected.
Leachate frequently seeps into
ground waters. Depending on the under-
lying soil and ground water conditions,
it may be somewhat attenuated and
diluted, or it may flow in a concentrated
form. It may seep slowly and build up
in a perched zone in the case of a
bathtub-shaped clay, or it may rapidly
flow from the site in the case of
fractured bedrock. Unfortunately there
is little ground water, monitoring at
disposal sites in this country. When
a downgradient or nearby drinking
water well exists, it frequently becomes
the first indicator of ground water
contamination. Our leachate damage
assessment study identified 36 municipal
disposal sites in 21 states which are
known to have contaminated drinking
water wells, and at least 2 more sites
are threatening. Six of these cases
were investigated in depth. A total
of 52 residential wells, 13 public
supply wells, and 7 industrial wells
were impacted with a total direct damage
123
-------
cost of $3.2 million at these six sites
(excluding the costs of the wells them-
selves). The major expenditures were
investigative and avoidance costs (the
contaminated ground water was abandoned
or avoided and replacement water was
piped in). In none of the cases has
the source of contamination been
corrected. In one of these cases
involving 25 residential wells, the
cost for a replacement supply, excluding
the cost of inconvenience, etc.,'was
over $20,000 per affected home. In
one case over $2 million has been spent
already and another $8 million is pos-
sible to correct the problem. Another
case, not one of the six in-depth
studies, is estimated to cost $4.3
million if deep-well injection of con-
taminated water is permitted, otherwise
more than $18 million to correct the
problem if leachate treatment is required.
The cost to move or retrofit a site is
very high. In Buffalo, New York, a land-
fill containing 2 million cubic yards was
moved (not because of a leachate problem)
by conveyors and barges to another site
6 miles away at a cost of $10.25 million.
Fifteen sites in eight states and
three foreign sites have been identified
where the extent of leachate migration
was determined. In the United States,
leachate from two sites has migrated
2 miles and from another site 1 mile.
In Krefeld, Germany, more than 5 miles
from one site (over an 18-year period)
was reported. Frequently, the extent
of migration in ground water is cut off
by ground water discharge into surface
waters.
The characteristics of leachate
are primarily a function of the types
of waste, amount of infiltrating water,
and pH. High concentrations of heavy
metals, other inorganics, organics,
and biological contaminants, are common
in raw leachate. The constituents
that migrate the furthest are those
which dissolve readily in water and
have a high ion exchange capacity.
These parameters are mostly aesthetic
impactors on ground water (Cl, Na, K,
etc.). The heavy metals (Pb, Hg, etc.),
complex organics, and bacteria, many
of which have health implications,
apparently tend not to migrate very
far unless there is a highly permeable
soil or free-channel flow as in frac-
tured bedrock.
Certainly this data demonstrates
adverse effects on the environment,
but how does one write criteria to
minimize the probability of their
occurrence?
There are two general types of
criteria, each with its advantages and
disadvantages: (1) performance and
(2) operational criteria. Performance
criteria specify environmental limits.
A continuum of possibilities exists,
including zero discharge, drinking
water limits, significant increase over
background, and specific levels for
different classes of facilities or
areas based on different geologic,
climatic, or water resource conditions.
Operational criteria, including "Best
Management Practices" or "Maximum
Practicable Technology", may specify:
ways to minimize infiltration (e.g.,
control of runon/runoff, cover material,
etc.); site location (e.g., out of
wetlands and flood plains, near dis-
charge zones, etc.); depth to ground
water; thickness of certain soils
beneath sites; or liners, etc. Both
types already exist in various state
regulations.
The selection of the type of
criteria must be based on: (1) ability
to predict environmental impact or
performance of specific operational
criteria or technologies, (2) avail-
ability (and cost) of effective preven-
tive (control) and corrective (retrofit
or treatment) technology, and (3) ability
to monitor and determine compliance.
If performance criteria are written,
a state permit agency still needs to
be able to predict for a new site the
effect of certain operational techno-
logies or criteria. If operational
criteria are written they must with
reasonable probability protect the
health and environment, i.e., achieve
performance criteria. That is, a cause-
effect relationship must be established
no matter what the type of criteria.
One approach we are considering
is to write performance criteria
(under §4004) and operational guidelines
124
-------
(under §1008). Performance criteria is
based on environmental impact assessments.
The operational guidelines xaould describe
the various technologies and costs to
achieve the performance criteria.
Operational criteria are more likely
to need updating and many equally effec-
tive or site specific operational
options may exist.
We are also considering the classi-
fication of geographical or hydrogeo-
logical areas. Class I would be critical
areas (e.g., certain wetlands, recharge
zones of major aquifers, permafrost
areas, etc.) for which zero discharge
or.degradation would be required. This
means either (1) do not put the site
there, (2) line the site and collect
and treat leachate, (3) prevent leachate
generation, or (4) utilize existing
natural features and special design
(e.g., a counterpumping program). The
states, which are the enforcement
agencies for the open dump prohibition
provisions of RCRA, would be able to
add to the list of critical or Class I
areas, and to designate major aquifers.
The less sensitive Class II and Class"III
areas would have other limits or may have
operational criteria and may utilize
natural attenuation and mixing zones
to achieve them, assuming a reasonable
attenuation/pollutant transport model
can be developed.
Compliance monitoring is a problem
b-fic_ause of the site-specific inexact na-
ture, and cost of monitoring, the gener-
• ally slow-moving, slow-cleansing char-
acteristics of ground water, and the
high cost and uncertainties of corrective
technologies. A typical question is
"Why monitor; if we find ground water
contamination, we do not know what to
do about1 it anyway?"
There are three major purposes
for monitoring: (1) as a warning^
mechanism for ground water users (to
show existence of contamination and
rate of leachate movement), (2) to
measure technological effectiveness
(cause and effect) , and '(3) for
evidential/compliance data for possible
enforcement and remedial program designs.
When and how to monitor to determine
compliance should probably be specified
by EPA. However, a cookbook approach is
impractical since monitoring systems must
be tailored to the conditions at each
site. Only general monitoring guidelines
are appropriate.
Through our monitoring efforts
we have identified a number of monitoring
problems that may inhibit compliance
investigations. We have also developed
some ideas on monitoring. Some basic
questions on compliance monitoring for
performance criteria include:
(1) Where should ground water
impact be monitored? Beneath
the wastes, or downgradient?
How far downgradient; at the
property line? How large
an attenuation/mixing zone
should be permitted?
(2) Where should upgradient
(background) wells be
located? How many? What
depths? Use cleanest up-
gradient or average of
upgradient for comparison
with downgradient wells?
What if the site is located
on a ground water divide,
and therefore has no "true"
background?
(3) Where should downgradient
wells be located? How many?
What depths? Use worst
downgradient or average of
downgradient; worst well
or worst parameter reading?
(4) What if the site is near
a discharge zone and it is
physically impossible to
get a drill rig downgradient?
(5) What about seasonal fluctua-
tions? Use worst level,
average, or other statistical
method?
(6) What constituents or para-
meters should be measured as
leachate indicators or for
determining potential health
effects?
Our current approach is to use
electrical resistivity survey to
identify potential contamination
125
-------
enclaves. If the resistivity works it
is useful in locating upgradient and
downgradient wells. Available site
information and surface observation,
such as reported earlier by Dwight
Sangrey, are used to estimate ground
water flow and stress areas, etc. We
do not recommend throughfill wells for
compliance monitoring. At minimum, one
to three background wells are used and
three to five downgradient wells.
Indicator parameters (Cl, Fe, COD,
Specific Conductance) are monitored
periodically. A one-tailed student
t-test is used to compare the data from
the worst downgradient well (presumably
nearest the worst part of the plume) with
what appears to be a reasonable back-
ground well. If the t-test shows a
statistically significant difference then
health parameters are monitored, and all
known information on the site is used
to determine if the disposal site is
indeed the most likely cause of the
statistical difference.
In summary, all the past and current
research on leachate generation, char-
acterization, attenuation, migration,
treatment, control, and monitoring must
be used as the basis for the criteria.
An option we are considering because
of the short statutory timetable of one
year is to publish interim criteria
this year and update this later when
the results of current research are in
and when the success of the interim
criteria is determined. We need your
help and guidance in the development
and review of the criteria. We plan
to send preliminary drafts to our Regional
Offices, to all states, and to selected
"experts" in the field, but any comments/
advice beforehand are appreciated.
126
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ATTENUATION OF LEACHATE POLLUTANTS BY SOILS
Mike H. Roulier
Solid & Hazardous Waste Research Division
U.S. EPA Municipal Environmental Research Laboratory
Cincinnati, Ohio
INTRODUCTION
In 1972 the Solid and Hazardous Waste
Research Division of the USEPA Municipal
Environmental Research Laboratory in Cin-
cinnati initiated two studies of municipal
solid waste leachate pollutant movement in
soil. The objectives of these contracts
were to determine the important mechanisms
controlling municipal pollutant attenuation
and movement in soils and to develop meth-
ods for predicting pollutant behavior in
soils. These studies have been completed
and although the final reports have not yet
been published, most of the results have
been published in the open literature.
This paper lists sources of available in-
formation on these projects and discusses
some of their significant findings. The
majority of the information in this paper
wa's drawn from draft final reports sub-
mitted by the projects and from the sources
cited in the bibliography at the end of
this paper.
Because it was assumed that clay would
be the fraction of the soil most active in
pollutant attenuation the work was split
into two projects. The work at the Uni-
versity of Arizona, Tucson, directed by
Dr. Wallace Fuller (Contract 68-03-0208),
dealt with representative whole soils from
the major soil groups in the United States
while the work at the Illinois State Geo-
logical Survey, Urbana, directed by Dr.
Neil Shimp and Dr. Robert Griffin (Contract
68-03-0211), dealt'with mixtures of pure
clay minerals. The soils used at Arizona
were collected from the B-horizon or below
to avoid high organic matter contents that
would be untypical of soils'below land-
fills. The clays used at Illinois were
commercially available materials (e.g.
southern bentonite) that were subsequently
purified by sedimentation, calcium satur-
ated, and mixed with sand to give materials
with a range of clay content and clay min-
eral type. Some of the physical and chem-
ical characteristics of these materials
are summarized in Tables 1 and 2.
The municipal leachates used by Illi-
nois were collected from landfills in the
area. Landfill leachate is not available
in Arizona because rainfall is so low in
comparison to potential evaporation. Conse-
quently, the Arizona project used an above-
ground tank and representative municipal
refuse to generate the leachate used in
their work. The ranges of characteristics
for leachates used at Arizona and Illinois
are listed in Table 3.
TABLE 3. LEACHATE CHARACTERISTICS
Parameter
PH
COD (mg/1)
Conductivity
(m mho/cm)
Fe (mg/1)
Ca (mg/1)
K (mg/1)
Arizona
(Dupage)
6.6-6.8
160-200
2.4-2.6
60-120
160-225
850-950
Illinois
(Blackwell)
6.8
1340-1362
7.2-10.2
3.0-4.4
46.8-49
491-516
Both projects packed the soils and soil
materials into columns, applied leachate
anaerobically to the columns with a contin-
uous flow, saturated system, and measured
contaminant concentrations in the applied
leachate and in the column effluents.
After a suitable period, the columns were
dismantled and the soils sectioned and
analyzed to determine the distribution of
contaminants retained by the soils. In the
127
-------
IS3
CO
TABLE 1
Some Characteristics of the Soils Used in
Research at the University of Arizona
Series
Kagram
Ava
Kalkaska
Davidson
Molokai
Chalmers
Nicholson
Fanno
Mohave
Mohave
(calcareous)
Anthony
Order1
Ultisol
Alfisol
Spodosol
Ultisol
Oxisol
Mollisol
Alfisol
Alfisol
Aridisol
Aridisol
Entisol
Soil
Paste
PH
4.2
4.S
4.7
6.2
6.2
6.6
6.7
7.0
7.3
7.8
7.8
Cation
Exchange
Capacity
meq/lOOg
2
19
10
9
14
26
37
33
10
12
6
Electrical Column Surface
Conductivity Bulk Area
of Extract Density
uhos/cm
225
157
237
169
1262
288
176
392
615
510
328
g/cm3
1.89
1.4S
1.53
1.89
1.44
1.60
1.53
1.48
1.78
1.54
2.07
»2/g
8.0
61.5
8.9
51.3
67.3
125.6
120.5
122.1
38.3
127.5
19.8
Free
iron
oxides
I
0.6
4.0
1.8
17.0
23.0
3.1
5.6
3.7
1.7
2.5
1.8
Total
Mn
ppm
50
360
80
4100
7400
330
950
280
825
770
275
Texture2 Major
Sand Silt Clay Clay Minerals
%
88
10
91
19
23
7
3
35
52
32
71
t
8
60
4
20
25
58
47
19
37
28
14
t
4
31
S
61
52
35
49
46
11
40
15
Kaolinite, Chlorite
Vermiculite,
Kaolinite
Chlorite, Kaolinite
Kaolinite
Kaolinite, Gibbsite
Montmorillonite ,
Vermiculite
Vermiculite
Montmorillonite, mica
Mica, Kaolinite
Mica, Montmorillonite
Montmorillonite, Mica
1. U. S. Department of Agriculture Comprehensive Soil Classification System.
2. U. S. Department of Agriculture System: Sand, 2mm - 0.05mm; Silt, 0.05mm - 0.002mm; Clay, <0.002mm diameter.
3. The dominant mineral is listed first.
-------
TABLE 2
COMPOSITION AND SOME PROPERTIES OF THE
MATERIALS USED IN THE COLUMN STUDIES AT THE ILLINOIS
STATE GEOLOGICAL SURVEY
Treatment1
%
Material
Cation
Exchange
Capacity
meq/lOOg
100
2
4
8
16
16
32
64
100
2
4
8
16
16
32
64
100
4
16
8
8
8
Sand
Montmorillonite
Montmorillonite
Montmorillonite
Montmorillonite
Montmorillonite
Montmorillonite
Montmorillonite
Montmorillonite
Kaolinite
Kaolinite
Kaolinite
Kaolinite
Kaolinite
Kaolinite
Kaolinite
Kaolinite
Illite
Illite
Montmorillonite
+ 8 Kaolinite
Kaolinite
+ 8 Illite
Kaolinite + 8 11
+ 8 Montmorillon
^Quartz sand added to
^Exponential notation
0
1
3
6
13
27
50
79
0
0
1
2
4
8
15
0
2
7
2
lite
ite 9
.0
*7
.3
.8
.3
-
.3
.7
.5
.2
.5
.0
.2
-
. 3
.2
.1
.7
. 7
.6
.8
.2
Bulk
Density
g
1
1
1
1
1
1
1
1
0
1
1
3
1
1
1
1
0
1
1
1
1
1
/cm3
.71
.71
.77
.79
.87
.93
.55
.23
.84
.68
.76
.80
.87
.94
.66
.22
.90
.80
.83
.95
.95
.64
Initial
Hydraulic
Conductivity"5
cm/sec
1
9
4
4
1
3
1
3
7
7
4
9
2
1
2
5
2
8
2
5
1
8
.27E
.45F
.34E
.70E
.22E
.40E
.27E
.05E
.26E
.44E
.78F.
.90E
.86E
.09E
.4 OF.
.45E
.98E
.17E
.68E
,35E
.4SF
.08E
-03
-04
-04
-04
-05
-07
-06
-07
-07
-04
-05
-04
-05
-06
-06
-07
-07
-04
-05
-07
-06
-06
make 100%
: E- 03 means 10" -
129
-------
Arizona study high concentrations of single
contaminants (As, Be, Cd, Cr, Cu, Pb, Hg,
Ni, Se, V, Zn) were added to the leachate
before it was applied to the soils; work
focused on the movement and retention of
these in soils. In the Illinois study the
leachates were applied without any addi-
tions; they contained very low levels of
heavy metal contaminants. Consequently the
Illinois column study focused on the move-
ment and retention of the more common
leachate contaminants (Na, K, Ca, Mg, Fe,
Mn, Cl, B, NH4, COD) and only limited in-
formation was obtained on the heavy metal
contaminants Pb, Zn, Cd, and Hg. Additional
batch work on pollutant retention was
carried out by both projects.
The Arizona project conducted sequen-
tial extractions of the soils from the
columns to determine not only the vertical
distribution of retained contaminants but
also the strength with which these contami-
nants were held by the soil. Each section
of soil from the column was extracted first
with water and then with 0.1 N HC1 to iden-
tify the readily Teachable materials and
those that were held so strongly that they
would be nearly unavailable for leaching.
The Illinois project conducted a series
of batch sorption tests to study the capac-
ity of the pure clays Montmorillonite and
Kaolinite to remove the contaminants Pb,
Cu, Zn, Cd, Cr, As, Se, and Hg from aqueous
solution and from several landfill
leachates. The major variables in these
single element studies were pH and the con-
centration of the contaminant. In addition
to identifying the removal capacities of
clays for contaminants in a leachate matrix,
this work also provided information on the
correct procedures for conducting such
studies.
The work on both projects has been
completed and draft final reports have been
submitted. Because some delay is expected
in publishing these final reports, a bib-
liography has been compiled of interim
publications by EPA and papers in various
journals relating to these two projects.
The bibliography is listed at the end of
this paper. The first two publications,
the symposia proceedings, are available
either from:
Technical Information Operations Staff
U.S. Environmental Protection Agency
26 West St. Clair Street
Cincinnati, Ohio 45268
or from the National Technical Information
Service. The NTIS numbers and prices for
paper (p) or microfiche (mf) are listed in
parentheses in the description of the sym-
posia proceedings in the bibliography. The
NTIS address is:
National Technical Information Service
U.S. Department of Commerce
Springfield, Virginia 22161
CONCLUSIONS OF THE ILLINOIS PROJECT
The Illinois project concluded that
Cl, Na, and water soluble organic compounds
(COD) were relatively unattenuated by pas-
sage through the columns of clay-sand mix-
tures; K, Nfyp Mg, Si, and Fe were moder-
ately attenuated. The cation exchange ca-
pacity of the clay minerals was concluded
to be the dominant removal mechanism for
these substances. Heavy metals such as Pb,
Cd, Hg, and Zn were present in the leachate
at very low levels; these metals were near-
ly immobile in the columns. The principal
attenuation mechanism for the heavy metals
was precipitation with resultant accumula-
tion in the surface layers of the columns.
As an aid in organizing and presenting
the results, an attenuation number was cal-
culated for each contaminant and treatment.
The ratio (C/C0) of the contaminant con-
centration measured in the column effluent
to the contaminant concentration present in
the leachate added to the column was plotted
graphically as a function of the number of
pore volumes of column effluent. Data for
the first pore volume was not included in
the calculations because it represents dis-
placement of deionized water present ini-
tially in the column. The area above the
curve, between one and eleven pore volumes,
expressed as a percentage of the total area
bounded by one to eleven pore volumes and a
C/Cg of zero to one, was taken as the atten-
uation number. In this system, contaminants
which were strongly retained by the soils
had high attenuation numbers while those
which passed readily through the columns had
low numbers. Greater amounts of B, Mn, and
Ca were eluted from the columns than were
applied in the leachate. Attenuation num-
bers for these constituents were reduced
by 100 and a negative sign was prefixed to
indicate net release.
The low mobility contaminants Pb, Zn,
Cd, and Hg had mean attenuation numbers
ranging from 96.8 to 99.8. The moderate
mobility contaminants Fe, K, NH4» and Mg had
130
-------
numbers ranging from 29.3 to 58.4. The high
mobility materials COD, Na, and Cl had num-
bers ranging from 10.7 to 21.3. Boron, Mn,
and Ca were eluted from the columns in
amounts greater than present in the leachate
and all had negative numbers.
Aluminum, Cu, Ni, Cr, As, S04, and
were present in the DuPage leachate in such
low concentrations that they were attenu-
ated nearly completely and never appeared
in the column effluents in significant con-
centration. Although these constituents
are expected to have different mobilities,
this cannot be demonstrated with the data
from the column effluents.
In the batch studies the adsorption in
leachate was 50 to 9Q% lower in most cases
than the clays' adsorption capacity for the
metal ions in pure aqueous solutions. The
pH of the leachate significantly affected
the amount of attenuation. It was con-
cluded that the heavy metal cations Pb, Cd,
Cu, Cr(III), Hg, and Zn attenuated pri-
marily by an exchange-adsorpotion mechanism
which was affected by pH and competition
from other cations. As the pH increased to
values of 5-6, a large increase in removal
was observed due to increased adsorption of
metal complex ions and formation of insolu-
ble heavy metal hydroxide and carbonate
compounds. At high pH the primary mech-
anism of attenuation for these ions was
precipitation.
To illustrate the magnitude of the
matrix-competition effect on sorption some
data for sorption of Pb as Pb(N03)2 on
kaolinite is listed below.
Solution Matrix
Sorption
(ug/g)
Deionized Water 15,800
0.1 M NaCl 11,100
DuPage Leachate 5,000
Blackwell Leachate 1,500
% of
Maximum
100
70
32
10
These differences in sorption from
different matrices are likely due to inter-
ference in the exchange process by other
solutes in the matrix competing for ex-
change sites on the clay. The 0.1 M NaCl
solution contains only one competing cation
while the leachates, particularly the
Blackwell contain many cations in high con-
centrations which could compete with the
added Pb for sorption sites. The DuPage
is an older (weak) leachate that was used
in the column studies and batch adsorption
studies. Its properties are listed in
Table 3. The Blackwell is a very strong
(young) leachate that was used in only a
few of the batch studies.
The effect of pH on the attenuation of
the heavy metal anions Cr(VI), As, and Se
was found to be the opposite of the cations
and it was concluded that precipitation was
not an important mechanism for the anions.
Because the adsorption of the anions corre-
lated well with the distribution in solu-
tion of the ionic species HCrOij, H2AsO;|,
and HSeOj it was concluded that the prin-
cipal attenuation mechanism for the heavy
metal anions was adsorption of the monova-
lent species. Because of the relative mag-
nitude of adsorption and their pH- related
behavior, the heavy metal anions would be
significantly more mobile at higher pH
values than the cations.
Measurements of the formation of Pb,
Cd, and Hg organic complexes in leachates
suggested that complexation was of secondary
importance to adsorption and precipitation.
This is likely due to competition from high
concentrations of other cations present in
leachates.
Significant reduction in hydraulic
conductivity of the materials in the column
studies was concluded to be due to microbial
activity. These observations suggest that
the hydraulic activity of clay-sand liners
placed in -the bottom of a-landfill will de-
crease with continued exposure to municipal
leachate.
CONCLUSIONS OF THE ARIZONA PROJECT
The major conclusions from the work at
Arizona are as follows:
1. Soil properties most useful in pre-
dicting attenuation {retardation of
migration) of contaminants by soils
are:
a. Clay content,
b. content of hydrous oxides, pri-
marily iron oxides,
c. pH and content of free lime, and,
d. surface area per unit weight of
soil.
131
-------
2. The mobility of the eleven contaminants
studied may be classified as follows:
a. most generally mobile - Cr(VI),
Hg, N1
b. least generally mobile - Pb, Cu
c. mobility varies with conditions -
As, Be, Cd, Se, V, Zn.
3. The characteristics of the leachate,
primarily electrical conductivity and
total organic carbon (TOC), signifi-
cantly affect the migration of con-
taminants.
4. Soils have a variable but significant
capacity to retain sorbed contaminants
against extraction and further leaching.
Some of the data supporting these con-
clusions is summarized in Tables 4, 5, and
6. Table 4 lists the correlation between
soil properties and the mass of contaminant
removed per gram of soil in the column, per
ml of leachate applied to the column. This
is a measure of the soil's ability to at
least temporarily attenuate the trace ele-
ment. Data for Pb, Cu, and Hg are not
shown; Pb and Cu were so immobile that they
did not migrate appreciably while Hg mi-
grated so rapidly that differences between
soils were slight. The clay content of a
soil and the surface area per unit weight
were by far the best single predictors of
a soil's attenuation properties. The
cation exchange capacity and content of
free iron oxides were also useful, though
much less than clay and surface area.
Correlations for surface area were best for
those elements added to the leachate as
divalent cations while the correlations for
free iron oxides were best for elements
(except for arsenic) added as anions.
Based on information in the literature, the
preferential sorption of As by hydrous ox-
ides was expected. The lack of a signifi-
cant correlation between As removal and
content of iron oxides may be due to inter-
ferences of the leachate organic fraction
in the sorption process.
The usefulness of combinations of soil
properties as predictors of attenuation was
analyzed via stepwise linear regression.
A regression equation using clay content,
surface area, and iron oxide content as
independent variables will predict removal
of Cd, Be, Ni, and Zn with significance at
the 1% level. The correlation coefficients
for equations relating clay, surface area,
TABLE 4
CORRELATION1 BETWEEN SELECTED SOIL PROPERTIES AND
MASS OF CONTAMINANT RETAINED2
ELEMENT
SOIL PROPERTIES
Clay
Content
Arsenic
Beryllium
Cadium
Chromium
Nickel
Selenium
Vanadium
Zinc
0.
0.
0.
0.
0.
0.
0.
0.
88-
78**
67*
56
59*
71*
84 + +
83**
0
0
0
-0
0
-0
0
0
PH
.22
.47
.48
.43
.51
.30
.16
.52
Cation
Exchange
Capacity
0.
0.
0.
0.
0.
0.
0.
0.
42
62*
60
21
79**
44
55
71*
Surface Area
Per Gram
0
0
0
0
0
0
0
0
.66*
.81**
.71**
.10
.88++
.39
.61*
.84**
Free Iron
Oxides
0
0
0
0
0
0
0
0
.60
.52
.46
.75**
.27
.68*
.59*
.50
1. Degrees of freedom are not the same for all correlations.
2. Per gram of soil in the column, per mi of leachate applied to the column.
* Significant at the 5* level
** Significant at the 1* level
+* Significant at the 0.1% level
132
-------
TABLE 5
THE AMOUNT OF SORBED TRACE ELEMENT EXTRACTED
FROM DIFFERENT SOILS BY WATER
Trace Element
Soils
Wagram 1 . s.
Ava si. c.1.
Kalkaska s.
Davidson c.
Molokai c.
Chalmers si.c.l.
Nicholson si.c.
Fanno c.
Mohave s.l .
Mohavep, c.l.
Anthony s.l.
As
0
3
2.
.
0
-
2
4.
0
11.
0
THE
Cd
9
5
5 2
5 1
.
-
1
5 1
2
5
3.
Cr
0
2
.5
4
5 1
-
10
1
0
2 6
5 0
TABLE 6
AMOUNT OF SORBED TRACE
DIFFERENT SOILS BY
Cu
.5
.3
.5
1.5
.1
-
0
3
.5
.2
3
ELEMENT
0.1 H
Hg
1.6
0
0
2.2
0
.5
0
.5
0
0
9
Ni
7
6
18
1
1.1
3
.2
2
4
.1
18
Pb
0
.7
.3
0
0
-
.2
.2
.4
.1
0
V
9
0
7.5
.4
.7
3.8
1.5
8
.3
23
28
Zn
8
5
5
3
2
-
1
1.2
2.5
.1
2.8
EXTRACTED FROM
HC1
Trace Element
Soils
Wagram 1 .s.
Ava s.c.l .
Kalkaska s.
Davidson c.
Molokai c.
Chalmers si .c.l .
Nicholson si.c.
Fanno c.
Mohave s.l.
Mohaveca c.l.
Anthony s.l .
As
11
11
18
5
0
-
11
24
n
20
13
Cd
90
85
100
77
87
-
75
80
89
74
100
Cr
8
7
16
7
5-
-
13
8
7
17
100
Cu
60
40
67
67
57
-
27
44
55
51
68
Hg
14
16
31
49
59
22
24
17
30
59
23
Ni
100
72
100
43
78
57
63
58
80
31
100
Pb
41
78
70
70
59
-
47
58
77
57
93
V
100
75
48
36
35
80
55
89
93
77
63
Zn
100
64
100
42
100
-
64
66
100
41
100
133
-------
and iron oxide with V and As are lower but
are still significant at the 5% level. In-
clusion of soil pH as an independent vari-
able improved the significance of the cor-
relation only for Cr and Se, elements that
are present in solution as anions.
Data on the amounts of trace elements
extracted from the soils after completion
of the column studies is listed in Tables
5 and 6. The acid extraction removed much
greater amounts than the water extraction.
The substantial amounts of sorbed trace
elements not removed by even the acid ex-
traction suggest a significant permanent
attenuation capacity for many soils.
As a qualitative summary, Figures 1
and 2 present a ranking of the soils used
in the project according to their attenu-
ation properties and a ranking of the con-
taminants according to their mobility in
the various soils. The physical and chem-
ical properties of these soils are sum-
marized in Table 1. Separate rankings are
given for contaminants present in the
leachate as cations and as anions because
of the differences in migration behavior.
Note that every change in the ordering of
soils when going from cations to anions
involves a higher ranking for soils having
a lower pH and/or a higher content of free
iron oxides.
It is concluded that clay content,
surface area, and content of hydrous oxides
and free lime will be the soil properties
most useful in selecting safe disposal
sites for municipal and hazardous wastes.
Additionally, the data suggests that use
of lime and iron oxides should be examined
as practical management tools for mini-
mizing the movement of contaminants from
landfills.
INCREASING MOBILITY
INCREASING
ATTENUATION
CAPACITY
x:::: MODERATE vX-x-x-x-:
'•:'•:'••:'•:• MOBILITY :-x:
FIGURE i
RELATIVE MOBILITY OF AX IONS USED
IN THE UNIVERSITY OF ARIZONA STUDY
134
-------
INCREASING MOBILITY
INCREASING
ATTENUATION
CAPACITY
MODERATE
MOBILITY
FIGURE 2
RELATIVE MOBILITY OF CATION'S IN SOILS USED
IN THE UNIVERSITY OF ARIZONA STUDY
COMPARISON OF RESULTS FROM THE PROJECTS
Although the projects used quite dif-
ferent materials and procedures the results
of the work are complementary. Both con-
cluded that the clay content and pH of the
soil would have a major influence on con-
taminant retention and movement in soils.
Likewise both concluded that leachate char-
acteristics would also have such a major
influence that it would be nearly impossi-
ble to extrapolate measurements in one
leachate-soil system to predict behavior
of contaminants in a different leachate-
soil system.
Illinois found that below pH 5 ex-
change-adsorption was the dominant removal
mechanism for the metal cations and that as
the pH increased through the range of 5 to
6, precipitation became a more significant
removal mechanism.
Arizona found weak correlations be-
tween cation exchange capacity and contami-
nant removal by all soils and concluded
that CEC would not have significant value
for predicting contaminant removal by soils.
This was likely due to the masking effect
of non-CEC removal processes active in
whole soils but not in a "clean" clay-sand
system and also due to the average pH of
the Arizona soils. The soils used in the
Arizona project were neutral to slightly
acid and only a few had pH of less than 5.
It is possible that a selection of soils
with a lower average pH would have given a
stronger correlation between CEC and metal-
lic contaminant removal.
Illinois found the following order of
mobility for the non-metallic contaminants
and iron:
Cl>Na>COD>Mg>NH4>K>Si>Fe
135
-------
Since Arizona concentrated on the metallic
contaminants no data is available from that
project for comparison. However, Arizona
noted that although soils removed different
amounts of COD, both the differences and
the amounts removed were slight and their
data would support Illinois' rating of COD
as a highly mobile contaminant.
The metallic contaminants, as a group,
were much less mobile than the non-metallic
contaminants listed above. The data from
the projects show Cu and Pb as the least
mobile, Hg, Cr(VI), and Se(IV) the most
mobile, and Cd, As(III), and Zn of inter-
mediate mobility. Work with Ni, V, and Be
(Arizona) and with Cr(III) and As(V) (lli-
nois) cannot be compared because these ele-
ments were not studied by both projects.
Arizona's data from column studies places
Ni in the high mobility group and V and Be
in the intermediate group. Illinois' data
from batch studies shows Cr(III) as even
less mobile than Pb and Cu; As(V) was be-
tween Cd and Zn.
SIGNIFICANT ADVANCES RESULTING
FROM THE PROJECTS
Some of the most significant advances
resulting from the projects were documenta-
tion of previously known effects. For in-
stance, clay content and pH were known to
affect the movement of contaminants and
knowledge of salt effects and the lyotropic
series suggested that sorption of a con-
taminant would be affected by the charac-
teristics of the leachate in which it was
contained. While the projects did not
provide fundamentally new information on
these subjects they did provide previously
unavailable quantisation of the magnitude
of the effects.
The contaminant removal data from the
Arizona project demonstrates the range of
effects, in a whole-soil system, of vari-
ations in pH, clay content, and iron oxide
content. The general trends of these
effects were known but information on their
magnitude for specific contaminants was
previously unavailable. Because of the
range in characteristics of soils included
in the study, the data also provides a
measure for estimating the contaminant
removal capacity of other soils not in-
cluded in the study. Similarly, the data
from the Illinois project on the effect of
contaminant concentration, pH, and compo-
sition of the carrier solution, though in
accord with expectations, were not pre-
viously available in sufficient quantity
or quality to make the design calculations
and explanations of removal mechanisms that
were provided by the project. The micro-
bially induced flow rate reductions and
the relative rankings of the contaminant
removal capacities of clay types shown by
the Illinois data were likewise useful
additions even though their general trends
were as expected.
Several advances were also made in
methodology and in explaining observed
field phenomena. The Arizona project de-
monstrated that landfill leachate is an
extremely labile material that rapidly
changes its appearance, physical properties,
and chemical species distribution upon ex-
posure to air. The substantial difficul-
ties that this causes during routine chem-
ical analyses were averted by developing
methods for handling leachate under C02-
This allowed the sampling and storage of
leachate without incurring air-induced
changes and improved confidence in the
results of subsequent chemical analyses.
While conducting the batch sorption
studies of contaminant removal by clays,
the Illinois project demonstrated that the
results of sorption studies are dependent
on the weight of.clay and the solution
volume and concentration, particularly when
de-sorbing ions can compete with contami-
nants for sorption sites on the clay. It
was shown that results of previous sorption
work were not as expected because the sys-
tem conditions did not comply with the
assumptions of the competitive Langmuir-
type equation used to display the data.
Indications are that measured contaminant
removal capacities of soil materials will
be increased when the conditions of the
experiment comply with the competitive
Langmuir-type assumptions.
The Illinois project observed large
amounts of calcium in the early increments
of effluent from the column studies. The
amount of calcium eluted corresponded very
closely to the amount of contaminants re-
moved from the leachate applied to the
columns. This suggested that the calcium
was released from the clays by exchange
with the contaminants and explained the
origin of a similar phenomena, the "Hard-
ness Halo" observed (but not explained) in
previously reported studies of actual
landfills. The Arizona project observed
136
-------
COD values of 1,000 to 10,000 mg/1 In the
early effluents from soil columns receiv-
ing leachates with COD values of only 160
to 200 mg/1. The "COD Halo", observed in
soils ranging in texture from sand to clay,
has not yet been reported in field studies.
These "halo effects" might serve as early
warnings in field monitoring, indicating
that the contaminant front is approaching
and that subsequent samples should be
analyzed in more detail.
RESEARCH NEEDED
As a conclusion to this discussion of
the Arizona and Illinois projects, several
of the research needs suggested by the
project results will be described. COD was
only slightly attenuated by any of the soils
or soil materials. This suggests that the
leachate organic fraction will be a signi-
ficant contamination problem and that fur-
ther work should be focused on the movement
of total organics and of specific groups of
organic materials in soils and soil materi-
als. Closely related to this is the need
to develop treatments to be applied at the
refuse-soil interface in a landfill to en-
hance degradation of organics and removal
of inorganic contaminants before the
leachate passes into the soil below the
landfill. One specific treatment, liners
of clay-sand or native, high-clay soils,
is presently in use for controlling liquid
movement from landfills. The project re-
sults indicate that, although this treat-
ment would have only a slight effect on
leachate organic movement, it would be
highly effective for removing inorganic con-
taminants and should be tested at a larger
scale under field conditions. Finally,
further work, taking account of leachate
characteristics as well as soil character-
istics, is needed to develop methods for
predicting contaminant movement and reten-
tion in soils as a basis for more rational
siting and operation of landfills.
BIBLIOGRAPHY
1. ^n: Gas and Leachate from Landfills:
Formation, Collection, and Treatment.
Proceedings of a Symposium at Rutgers
University, March 25 and 26, 1975.
EPA-600/9-76-004, March 1976. Solid
and Hazardous Waste Research Division,
EPA-MERL, Cincinnati, Ohio 45268.
196 p. (NTIS: PB251161/AS (p): $7.50,
(mf): $2.25)
Fuller, W. H. and N. Korte. Atten-
uation Mechanisms of Pollutants
Through Soils, pp 111-122.
Griffin, R. A. and N. F. Shimp.
Leachate Migration Through Selected
Clays, pp 92-*95.
Jin: Residual Management by Land Dis-
posal. Proceedings of the Hazardous
Waste Research Symposium at the Uni-
versity of Arizona, February 2-4, 1976.
EPA-600/9-76-015, July 1976. Solid and
Hazardous Waste Research Division, EPA-
MERL, Cincinnati, Ohio 45268. 280 p.
(NTIS: PB256768/AS (p): $9.25, (mf)
$2.25)
Alesii.B. A. and W. H. Fuller. The
Mobility of Three Cyanide Forms in
Soil, pp 213-223.
Griffin, R. A. Effect of pH on Re-
moval of Heavy Metals from Leachate
by Clay Minerals, pp 259-.26S.
Korte, N., et al. Trace Element
Migration in Soils: Desorption
of Attenuated Ions and Effects
of Solution Flux, pp 243-258.
Frost, R. R. and R. A. Griffin, 1977.
The Effect of pH on Adsorption of
Arsenic and Selenium from Landfill
Leachate by Clay Minerals. Soil Sci.
Soc. Amer. J. 41:53-57.
Frost, R. R. and R. A. Griffin, 1977.
The Effect of pH on Adsorption of
Copper, Zinc, and Cadmium from Land-
fill Leachate by Clay Minerals. J.
Env. Sci. & Health Part A, 12(4).
Fuller, W. H., et al., 1976. Contri-
bution of the Soil to Migration of
Certain Common and Trace Elements.
Soil Sci. 122:223-235.
Fuller, W. H. Movement of Selected
Metals, Asbestos, and Cyanide in Soils:
Applications to Waste Disposal Prob-
lems. EPA-600/2-77-020, April 1977.
Solid and Hazardous Waste Research
Division, EPA-MERL, Cincinnati, Ohio
45268. 257 p.
Griffin, R. A., et al. Attenuation of
Pollutants in Municipal Landfill
Leachate by Passage Through Clay.
Env. Sci. and Technol. 10:1262-1268,
December 1976.
137
-------
8. Griffin, R. A. and N. F. Shimp. Effect
of pH on Exchange-Adsorption of Lead
from Landfill Leachates by Clay Min-
erals, Env. Sci. and Techno!. 10:1256-
1261. December 1976.
9. Griffin R. A., et al. Attenuation of
Pollutants in Municipal Landfill
Leachate by Clay Minerals: Part I -
Column Leaching and Field Verification.
Environmental Geology Notes No. 78,
November 1976. Illinois State Geo-
logical Survey, Urbana, Illinois. 34 p.
10. Griffin, R. A., et al. Attenuation of
Pollutants in Municipal Landfill
Leachate by Clay Minerals: Part 2 -
Heavy Metal Adsorption Studies. En-
vironmental Geology Notes No. 79,
April 1977. Illinois State Geological
Survey, Urbana, Illinois, 47 p.
11. Korte, N. E. J. Skopp, E. E. Niebla,
and W. H. Fuller, 1975. A Baseline
Study on Trace Metal Elution from
Diverse Soil Types. Water, Air, Soil
Pollut. 5:149-156.
12. Kbrte, N. E., E. E. Niebla, and W. H.
Fuller, 1976. The Use of Carbon Dio-
xide to Sample and Preserve Natural
Leachates. J. Water Pollut. Control
Fed. 48:959-961.
13. Korte, N. E. et al., 1976. Trace
Element Movement in Soils: Influence
of Soil Chemical and Physical Pro-
perties. Soil Sci. 122:350-359.
14. Marion, G. M. et. al., 1976. Aluminum
and Silica Solubility in Soils. Soil
Sci. 121:76-85.
15. Niebla, E. E. et al., 1976. Effect of
Municipal Landfill Leachate on Mer-
cury Movement through Soils. Water,
Air, and Soil Pollut. 3:399-401.
16. Skopp, J. and A. W. Warrick, 1974. A
Two-Phase Model for the Miscible Dis-
placement of Reactive Solutes in Soils.
Soil Sci. Soc. Amer. Proc. 38:545-550.
138
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EFFECT OP MUNICIPAL LANDFILL LEACHATE ON THE
RELEASE OF TOXIC METALS FROM INDUSTRIAL WASTES
M. J. Houle, D.E. Long, R.E. Bell, J.E. Soyland, and R.R. Grabbe
Chemical Laboratory Division, US Army Dugway Proving Ground, Dugway, Utah
84022
ABSTRACT
The potential increase in hazard resulting from the co-disposal of industrial wastes
with municipal refuse was tested using wastes from several different industries; namely,
electroplating waste, inorganic pigment waste, and nickel-cadmium battery production
waste. Known weights of each waste were mixed with municipal landfill leachate and water.
The samples were extracted for 24 and 72 hours, filtered, and the filtrates analyzed for
cadmium, chromium, copper, and nickel by atomic absorption spectrophotometry. The wastes
were recovered, mixed with fresh aliquots of municipal landfill leachate or water and re-
extracted. This serial batch extraction was carried out seven times. The concentrations
of cadmium, copper, and nickel in the municipal landfill leachate extracts were much
higher than was found in water extracts. Depending on the Waste, metal, and cumulative
extraction volume, the increase in solubilization of the metals by the municipal landfill
leachate ranged from approximately 100 to 3000 times higher than with water. Chromium
was the only exception. The concentration of Cr metal in both solvent extracts was
approximately the same (or slightly greater in the water extracts). These findings
dramatically demonstrate the potential hazard that may result from the disposing of
certain industrial wastes together with municipal refuse. This raises the serious
question as to the advisability of co-disposal in general.
INTRODUCTION
As municipal refuse decomposes in
landfills, resultant decomposition
products can dissolve in the water re-
leased from the refuse itself. The
volume of this liquid, or leachate, is
increased by rainfall, snow melt or runoff,
especially in improperly constructed land-
fills. If the volume exceeds the "field
capacity" of the refuse layer, the
leachate passes through the refuse into
the underlying soil and may eventually
find its way into the ground water. If
this underground water is used by a
municipality for culinary purposes, the
entrance of the landfill leachate
potentially presents a serious-health
hazard. In addition, reclamation of the
disposal site and water supply may require
years and be extremely costly (1) .
Industrial waste are often co-
disposed with municipal refuse. The
Municipal Environmental Research
Laboratory, U.S. Environmental Protection
Agency, Cincinnati, was concerned that
municipal landfill leachate may solubilize
toxic metals contained in industrial wastes.
This was investigated here by leaching
wastes from several different industries;
namely, electroplating, inorganic pigment,
and nickel-cadmium battery production
wastes, using water or municipal landfill
leachate. The concentration of cadmium,
chromium, copper, and nickel, was measured
in the resultant samples.
MATERIEL AND METHODS
Electroplating Waste
The electroplating waste is produced
in plating, phosphatizing, and metal
cleaning operations. The metals are pre-
cipitated from the waste water by the
addition of lime or caustic soda. The
139
-------
weights of the four metals in the waste
were: cadmium 0.8 percent (w/w) ,
chromium 10.5' percent, copper 3.2 percent,
and nickel 1.0 percent.
Inorganic Pigment Waste
Waste water from the manufacturing of
inorganic pigment contains both dissolved
and suspended solids. After treatment to
destroy cyanide and to reduce hexavalent
chromium, the pH is raised to eight with
lime. A flocculating polymer is added to
promote precipitation. The weight of the
four metals in the waste were: cadmium
0.17 percent, chromium 7.0 percent, and
copper 0.42 percent. (The nickel content
was not determined^
Nickel-Cadmium Battery Productive Waste
This waste arises from the washing of
electrodes upon which cadmium and nickel
had been deposited. The washings are made
alkaline (pH 11-12) with sodium hydroxide.
This precipitates both metals as hydroxide
salts. Most of the precipitates are re-
covered from the alkaline waste water.
However, "fines" are lost as the waste
water is pumped to the holding lagoon.
The cadmium weight was 51 percent and the
nickel 10.1 percent.
Municipal Landfill keachate
The municipal landfill leachate used
in this study was collected from the
experimental test cell in Boone County,
Kentucky. The leachate is composed of the
liquid content of the refuse combined with
natural precipation. The leachate has
been used in other studies and extensively
characterized (2,3) so only pH, specific
conductance, acidity/alkalinity, and
toxic metal content were measured. A few
visual observations were made as to color,
turbidity, effect of air exposure and its
interaction with the industrial wastes.
The municipal landfill leachate was
stored in a carbon dioxide environment at
4°C. When received, the leachate was a
light bluish black in color and contained
some greyish black suspended solids. The
initial pH was 5.6 and the specific con-
ductance 12,650 micromhos. The alkalinity
was measured by titrating an aliquot of
leachate with 0.102 N HCl. The alkalinity
was calculated to pH 4.7 as recommended in
Standard Methods (4). The alkalinity was
1.0x10 equivalent of acid per milliliter
of leachate. The only toxic metal found
in a significant concentration was zinc
(60mg/l). The other metals of interest
were very low.
Upon standing, even at 4°C and in a
carbon dioxide invironment, the leachate
changed. After one week the pH was 5.8.
The suspended solids increased and the
specific conductance increased to 14,900
micromhos. After several hours exposure to
air the color turned dark brown. The
suspended solids increased to the point
where the leachate was very turbid. Gas
was evolved during this time.
These observations and measurements
indicate the problems to be encountered
while working with municipal landfill
leachate. Leachate samples collected at
different landfills will vary widely in
composition as will leachate collected from
the same site at different times of the
year.
Extraction of the Waste Samples
The serial batch extraction procedure
used in this study is outlined below. A
20 gram portion of waste was weighed into
an Enlenmyer flask. Two hundred
milliliters water or municipal landfill
leachate was added to the flask. The flask
was stoppered and mixed for 72 hours. The
mixture was filtered with vacuum through a
Buchner funnel. The filtrate was filtered
a second time through 0.45 micron millipore
filter and then analyzed. The waste was
recovered from the Buchner funnel filter
pad and a second 200 milliliter aliquot of
water or municipal landfill leachate added
and mixed for 72 hours. The waste was
again filtered as described above. This
serial batch extraction was repeated seven
times.
Analysis
The pH and specific conductance was
measured in each extraction sample. The
samples were then acidified with HNC>3 to
an acidity of one percent. The con-
centration of cadmium, chromium, copper,
and nickel in the waste extracts was
measured by atomic absorption spectro-
photometry using an air-acetylene flame.
The lower detection limits for the metals
were 0.02 mg/1 for cadmium, copper, and
nickel and 0.05 mg/1 for chromium. Very
little interference in the analysis was
found.
140
-------
RESULTS AND DISCUSSION
Electroplating Waste
Figure 1 is a plot of the serial
batch extraction of cadmium from electro-
plating waste by water or municipal land-
fill leachate. The extraction number (or
batch) is plotted on the X-axis. The
serial batch extraction was carried out
seven times. The volume is expressed as
milliliters per gram waste, e.g. ,20 grams
waste extracted with 200 milliliters
solvent are equivalent to 10 milliliters
per gram. The 20 grams of waste were ex-
tracted by a total of 1400 milliliters
solvent (70 milliliters per grams of
waste). The batch serial extraction can
also be expressed in terms of equivalent
months. This is intended to show the time
that would have elapsed if the waste were
continuously leached by one of the above
solvents at a rate of 1.3xlO~4 centimeters
per second.
The concentration of cadmium found in
each batch sample is plotted on the y-axis
(note the y-axis is logarithmic). The
dashed line histogram represents the con-
centration of cadmium found in the samples
extracted by water. The solid line
histogram is the concentration of cadmium
found in the municipal landfill leachate
extracts of the waste.
The results show the municipal land-
fill leachate was far more efficient than
water in extracting cadmium from the
electroplating waste. The total weight of
cadmium extracted from each gram of waste
by water was 69 micrograms. Municipal
landfill leachate extracted about 70
times more or 4,380 microgram cadmium per
gram waste.
Figure 2 is a plot of chromium ex-
tracted from electroplating waste by both
solvents. As compared to cadmium, a very
small amount of chromium was extracted.
However, municipal landfill leachate ex-
tracted more than twice as much chromium
as water. Although a substantial quantity
of chromium was present in the waste, most
was probably chromium hydroxide. This
form of chromium is very insoluble.
Figures 3 and 4 are plots of the
weight of copper and nickel extracted
from the electroplating waste by municipal
landfill leachate and water. The
municipal landfill extracted over 1,000
times more copper (7,961 micrograms per
gram waste) than water (7 micrograms per
gram). It also extracted more than 24
times more nickel than water (965 micro-
grams per gram compared to 39 micrograms
per gram).
electroplating waste was fairly
soluble in water. Approximately three per-
cent was dissolved in the first batch.
However, the soluble ions in the subsequent
extracts dropped off rapidly, decreasing
from specific conductance of 6,400 micro-
mhos in the first extract to 2,200 micro-
mhos in the seventh extract. In contrast,
the specific conductance of the municipal
landfill leachate extracts remains very high
throughout all the serial extractions.
Inorganic Pigment Waste
Figures 5 through 8 are plots of
cadmium, chromium, copper, and nickel ex-
tracted from inorganic pigment waste by
municipal landfill leachate and water.
Over 300 times more cadmium was extracted
by municipal landfill leachate than water
(626 micrograms per grams compared to 2
micrograms per grams). Copper was not
detected in the water extracts of the
waste. However, a total of 25 micrograms
copper per gram waste was found in the
municipal landfill leachate extracts. In
addition, at least 47 times more nickel was
extracted by the municipal landfill
leachate. Only chromium was extracted by
water in larger amounts (approximately four
times) than by municipal landfill leachate.
The inorganic pigment waste was much
less soluble in water than was electro-
plating waste. Approximately one percent
of the waste dissolved in the first ex-
traction step and dropped rapidly in sub-
sequent extractions. However, the weight
of material extracted by municipal landfill
leachate was high even after seven extract-
ions.
Nickel-Cadmium Battery Production Waste
Figure 9 is a plot of the cadmium ex-
tracted from the nickel-cadmium battery
production waste by water and municipal
landfill leachate. Water extracted only a
total of 131 micrograms per gram of waste.
However, landfill leachate extracted
nearly 870 times more for a total of
114,490 micrograms. The extraction of nickel
from this waste was much smaller than
cadmium as shown in Figure 10. However,
the municipal landfill leachate extracted
at least 200 times more nickel than water.
Nickel-cadmium battery waste was the
most soluble waste used in this study.
141
-------
100.0
10.0,,
Hi
C-J
e>
0.1
Total ug/g
Leachate * 4380
Water - 69
0 10 20 30 40
VOLUME (ML/GM WASTE)
L
fc
50 60 70
0 1 234 5 f
Leachate
Water
EQUIVALENT MONTHS
Figure 1. Comparison of Solubilization of Cadmium from Electroplating Waste by
Landfill Leachate and Water
Total
10-0 IT
1.0
0.01
Leachate - 57
Water -23
10 20 30 40 50
VOLUME (ML/GM WASTE)
60
70
0
3 4
EQUIVALENT MONTHS
Figure 2. Comparison of Solubilization of chromium from Electroplating Waste by
Landfill Leachate and Water
142
-------
1000.0
100. 0/
j 10.0.
I
3
: i.o
3
X
0.10
0.01
Total ax/a
Leachate - 7961
Water » 7
Leachate
Water
10 20 30 40 50
VOLUME (ML/GM WASTE)
60
70
12 34 5 67
EQUIVALENT MONTHS
Figure 3. Comparison of Solubilization of Copper from Electroplating Waste by
Landfill Leachate and Water
e>
00. 0'
10,0
1.0
Total ug/g
Leachate « 965
Water - 3S
10
20 30 40 50
VOLUME (ML/GM WASTE)
60
70
012345
EQUIVALENT MONTHS
Figure 4. Comparison of Solubilization of Nickel from Electroplating Waste by
Landfill Leaohate and Water
143
-------
100.0
10,0
dl-°
3
s
»
^0.10
_
Total ua/g
l-eachate « 626
Water = 2
Leachate
Water
0.01
10 20 30 40 50
VOLUME (ML/GM WASTE)
60
70
123456
EQUIVALENT MONTHS
Figure 5. Comparison of Soltibilization of Cadmium from Pigment Waste by
Landfill Leachate and Water
10.Or
1.00
l-I
as
W
&
O
3.
0.10
0.1
Total
Leachate « 25
Water » <1
10 20 30 40
VOLUME (ML/GM WASTE)
50
60
70
012345
EQUIVALENT MONTHS
Figute 6. Comparison of Solubllization of Copper from Pigment Waste by
Landfill Leachate and Water
-------
Total
10.0
1.0 -
Leachate - 93
Water » 406
Water
Leachate
0 10 20 30 40 50 60 70
VOLUME (ML/GM WASTE)
012 34 5 6
0.1
EQUIVALENT MONTHS
Figure 7. Comparison of Solubilization of Chromium from Pigment Waste by
Landfill Leachate and Water
10.Or
Total
Leachate • 237
1.00
0.10
0.01
•
.__.__ .— —
Water « 5
0 10 20 30 40 50 60 7Q
. . VOLUME (ML/GM WASTE)
012345
EQUIVALENT MONTHS
Figure 8. Comparison of Solubilization of Nickel from Pigment Waste by
Landfill Leachate and Water
145
-------
Total ug/g
i.oooo.o
1000.0
100.0
1 10.0
B
x
19 01.0
a
0.10,
0.01
Leachate « 114,490
Water o Til
Hater
0 10 20 30 40 50 60 70
VOLUME (ML/GN WASTE)
0 1 234 5 6
EQUIVALENT MOUTHS
Figure 9. Comparison of Solubilization of Ca<3rai\ja from Ni-cd Battery Waste by
Landfill Leachate and Water
1 000.0
100.0
10.0
o
1.0
0.1
Total ug/8
Leachate « 5210
Hater - 25
10 20 30 40 50
VOLUME (ML/GM WASTE)
60
70
6
012345
EQUIVALENT MONTHS
Figure 10. Comparison of Solubilization of Nickel from Ni-cd Battery Waste by
Landfill Leachate and Water
146
-------
Landfill Loachate
0.0
34567
CUM VOLUME (ML/GM WASTE)
10
Figure 11 • Comparison of Continuous Leaching of Cadmium from Ni-Cd Battery Waste
by Landfill Leaohate and Water
100.0
90.0
80.0
70.04
< 60.0
| 50.0
" 40.0
30.0
20.0
10.0
O.Oj,
Landfill Leaohate
012 34 567 39 10
CUM VOLUME (ML/GM WASTE)
Figure 12. Comparison of Continuous Leaching of Nickel from Ni-Cd Battery Waste
by Landfill Leachate and Water
147
-------
In the first batch extract, approximately
6.5 percent of the solids dissolved in
water but very little cadmium or nickel
appeared; instead, the dissolved solids
were primarily excess base. Subsequent
batch extractions yielded much less
dissolved solids, and as the excess base
washed out, the pH dropped and the cadmium
and nickel became soluble. As observed
with the other wastes, the municipal
landfill leachate dissolved more material
from this waste than did water.
Because of the high solubility of
the nickel-cadmium battery waste and the
ease with which both metals were extracted
from the waste in the serial batch extract-
ions, this waste was also used to compare
water with municipal landfill leachate by
continuous column extractions. The waste
was packed into columns made from 37 milli-
meter diameter glass tubing with an 8
millimeter diameter tip on the bottom. A
piece of glass wool was placed over the
bottom hole and covered with washed quartz
sand (Ottawa Sand). One hundred grams of
the waste was mixed with an equal weight
of Ottawa Sand and packed into the column,
occupying a depth of approximately 10
centimeters. (It was mixed with sand so
that the desired flow rate of 1.3 x 10"
centimeters per second could be obtained
through this dense waste.)
Figures 11 and 12 are plots of the results
of the columnar extraction of cadmium and
nickel from the waste by the two solvents.
The figures show that the water extracted
more of both metals initially than did
municipal landfill leachate (the concen-
tration of both metals in the extract was
not measured at zero time for water).
However, the concentrations dropped off
rapidly in the water extracts while they
increased in the municipal landfill leach-
ate extracts. These results further demon-
strate the increase in potential hazard if
industrial and municipal wastes are dis-
posed of together.
CONCLUSIONS
It has been shown that municipal
landfill leachate will extract significant-
ly greater amounts of toxic metals (cad-
mium, copper, chromium, and nickel) from
electroplating, inorganic pigment, and
nickel-cadmium battery production wastes
than will water. It was concluded that if
hazardous industrial wastes are codisposed
with municipal refuse, the disposal site
must be carefully managed because of the
potential increase in hazard due to the
increased solubilization of these metals
by municipal landfill leachate.
ACKNOWLEDGEMENT
This study was part of a ma5or re-
search program on the migration of hazard-
ous substances through soil, which is now
being conducted by U.S.Army Dugway Proving
Ground under the auspices of, and funded by
Environmental Protection Agency, Municipal
Environmental Research Laboratory, Solid
and Hazardous Waste Division, Cincinnati>.
Ohio, under Interagency Agreement EPA-1AG-
04-0443. Dr. Mike H. Roulier is the EPA
Program Manager for this project.
REFERENCES
1. G.A.Garland and D.C.Mosher, "Leachate
Effects of Improper Land Disposal/"
1975, Waste Age.
2. E.S.K.Chian and F.B.DeWalle,"Compilat-
ion of Methodology Used for Measuring
Pollution Parameters of Sanitary Land-
fill Leachate,'' 1975, prepared for Solid
and Hazardous Waste Research Division,
Municipal Environmental Reserach Lab-
oratory, U.S.Environmental Protection
Agency, Cincinnati, Ohio 45268, EPA-
600/3-75-011.
3. "Municipal Solid Waste Generated Gas
and Leachate," 1976, Disposal Branch,
Solid and Hazardous Waste Research Div-
ision, Municipal Environmental Research
Laboratory, U.S.Environmental Protect-
ion Agency, Cincinnati, Ohio 45268.
4. "Standard Methods for the Examination
of Water and Waste Water," APHA,AWWA,
WPCH, 1971, p.370, 13th Edition.
148
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COMPATIBILITY OF LINERS WITH LEACHATE
H. E. Haxo, Jr.
Matrecon, Inc.
Oakland, California
ABSTRACT
This paper presents the results of one year of exposure of various liner materials to
sanitary landfill leachate. These materials include:
Six admix materials:
2 Asphalt concretes
1 Soil asphalt
2 Asphaltic membranes
1 Soil cement
Six primary flexible polymeric liner specimens based
upon the following polymers:
Butyl rubber
Ethylene propylene rubber (EPDM)
Chlorinated polyethylene (CPE)
Chlorosulfonated polyethylene
Polyethylene (PE)
Polyvinyl chloride (PVC)
Additional small membrane specimens, including polypropylene, polybutylene, and neoprene,
were also exposed and tested.
The first year of exposure did not result in losses of impermeability in any of the
liners. There were losses, however, in the compressive strength of the admix liner ma-
terials. Also, there were losses in the physical properties of some of the polymeric mem-
branes and swelling of most of these membranes. The seams of several lost strength, with
the heat-sealed seams holding up best as a group.
Among the flexible membranes, the crystalline polymers, polyethylene, polypropylene,
and polybutylene, sustained the least change during the first year of exposure; however,
these membranes are susceptible to easy puncturing and tearing which would cause problems
on installation. The thermoplastic membranes, chlorinated polyethylene, Chlorosulfonated
polyethylene, and polyvinyl chloride, tended to swell the most. The vulcanized rubbery
liner materials, e.g. butyl and EPDM, changed little during the exposure period, but had
the lowest initial seam strength.
The data presented must be cpnsidered as preliminary in an ongoing project; it is pre-
mature to estimate the service lives of the various materials or to make relative compari-
sons among them for use in a given installation without consideration to costs and to the
specifics of the installation.
149
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INTRODUCTION
The use of impervious materials to line
sanitary landfills appears to be a promising
method for intercepting and controlling
leachate generated in a fill to prevent it
from polluting surface and ground water.
Although many liner materials appear to be
potentially useful for this purpose, infor-
mation available regarding the effects of
exposure to leachate on them is very limited,
even for relatively short exposure times.
The project on which this paper is based
was undertaken to assess the effects of land-
fill leachate on the properties of a broad
range of liner materials. They include as-
phaltic membranes, soil asphalt, soil ce-
ment, and flexible polymeric membranes.
Soils and clays were specifically excluded
from the investigation as they are being
covered in other projects.
TECHNICAL APPROACH AND REVIEW
Technical Approach
Taking into account the wide diversity
in the types of materials that are candi-
dates for lining landfills and the urgent
need for information regarding the relative
merits of the various liners and their ex-
pected lifetimes in a landfill environment
(1,2), the following overall approach is
being taken:
- Expose liner specimens individually to
leachate under pilot conditions that sim-
ulate as closely as possible those condi-
tions a liner would encounter at the bot-
tom of a real landfill. The simulated
sanitary landfills are designed and con-
structed to ensure anaerobic conditions,
and the leachate generated is representa-
tive of the leachate generated in sanitary
landfills.
- Select for exposure testing 12 specific
liner materials from the various types of
liner materials that have been successful-
ly used in lining pits, ponds, lagoons,
canals, etc., to prevent seepage of water
or various wastes, and that appear suit-
able for lining sanitary landfills. Soils
and clays are excluded from this project
as they are covered in other investiga-
tions.
- Each test specimen is of sufficient size
so that physical tests can be made to
measure the effects of exposure to
leachate and, if appropriate, a typical
seam is incorporated for testing.
- Subject the liner specimens to appropriate
tests for the specific type of liner.
Measure properties that could be expected
to reflect on the performance of..the liner
in sanitary landfills and determine the
changes in properties as a function of
exposure time.
- Seal the liner specimens in individual
simulated landfills so that whatever seep-
age might come through can be collected
and tested. This required special efforts
to avoid leachate by-passing the liner or
channeling through the liner, particularly
in the cases of soil cement and soil as-
phalt liners.
- Create equal conditions in all simulated
fills, so that valid comparison between
liners can be made. To accomplish this,
fill the simulated landfills with well-
compacted, shredded municipal refuse. Com-
paction, composition, and amount of refuse
are as equal as possible in each of the 24
cells so that a relatively highly concen-
trated and equal leachate is generated in
all the cells.
- After the refuse in the cells is saturated,
i.e. brought to "field capacity", generate
leachate by adding 1 inch of tap water
every 2 weeks (26 inches per year) and al-
low leachate to pond on the liner at a
depth of about 1 foot by draining and col-
lecting leachate every other week.
Environment of a Liner in a Landfill
As with any product, the service life
of a liner will depend upon the materials of
which it is made and on the environment in
which it must function. Some important con-
ditions that exist at the bottom of a land-
fill which should have major effects on ser-
vice life are:
- As shown in Figure 1, the liner is gener-
ally placed on a relatively firm, smooth
surface that has been graded to allow
drainage and compacted. Rocks, stumps,
and other objects that could cause crack-
ing of hard liners have been removed. Set-
tlement, however, could cause a brittle or
weak liner to fail.
- Only modest hydraulic head pressure on the
liner exists, since drainage above
150
-------
I— •i^-V'l
CONCEPT OF LINING A SANITARY LANDFILL
the liner is designed to take place con-
tinually. Before refuse is added a por-
ous soil is placed on the liner to protect
it from puncture.
- At the bottom of a compacted landfill, an-
aerobic conditions normally exist, i.e.
there is no oxygen present to cause oxida-
tive degradation of the liner.
- The liners are in total darkness; there is
no ultraviolet light which can degrade
many organic and polymeric materials.
- The conditions are wet, particularly if
leachate is being generated regularly,
and could result in the leaching of in-
gredients, e.g. the plasticizer in PVC,
from a liner compound.
- The temperature at the bottom of a land-
fill is usually cool, in the range of 40
to 70 F, which is favorable for extended
service life. High temperature can be
generated within the fill if air is pres-
ent, a condition which exists when refuse
is first placed or is not compacted.
- Acidic conditions due to the leachate may
deteriorate some liners, e.g. soils and
soil cement.
- High saline concentrations in leachate may
exchange with clays and soils to increase
permeab ility.
- Dissolved organic constitutents in the
leachate may degrade some of the liners
made of organic materials, e.g., polymer
membranes and asphaltic liners.
The effects of these environmental con-
ditions will differ on the various barrier
materials. However, it appears that mechan-
ical failure during installation or during
operation of the fill due to settling of the
soil is the most probably source of failure
of a liner in a landfill.
Simulated Landfills
The leachate generator and exposure
cell, shown in Figures 2 and 3, was de-
signed (1,2) to create conditions which
closely simulate the environment in a land-
fill.
BASE OF LEACHATE GENERATOR
Twenty-four of these simulated land-
fills have been constructed at the Sanitary
Engineering Research Laboratory of the Uni-
versity of California, Berkeley. The site,
at the Richmond Field Station of the Uni-
versity, on San Francisco Bay, has a moder-
ate and uniform temperature over the entire
year, mostly in the 55 to 60 F range.
The 12 liner materials were mounted in
duplicate in the 24 generators. 12 of
these generators were dismantled and the
liners removed and tested after 12 months
of exposure to leachate and the remaining
12 will be dismantled after 42 months of
exposure.
Selection of Specific Materials for Expos-
ure Testing
The selection of specific liner ma-
terials for testing as barriers in the
151
-------
simulated landfills involved two major
steps:
1. Selecting a type of material and
polymer for the admix liners and flexible
membranes.
2. Within each type, selecting a spe-
cific material or composition.
In making this final selection of spe-
cimens to test the following factors were
considered:
1. The thickness of each material se-
lected was typical of that normally employed
except that, if there was a choice, thin lin-
ers were selected so as to accelerate the
effects of the leachate.
2. Within a type, high quality compo-
sitions were selected, e.g., in selecting
specific membranes from those of a given
type available, the membrane with best phys-
ical properties was generally selected.
No attempt was made to obtain liner sa-
mples from all liner producers, but to se-
lect specific liners that were representa-
tive of the respective types of materials.
The specific liners selected and mount-
ed as barriers in the bases of the simulated
landfills include six flexible synthetic
polymeric membranes and six admix liner ma-
terials. They are listed in Table 1 with
their respective thicknesses.
TABLE 1. LINER MATERIALS SELECTED FOR
LEACHATE EXPOSURE TESTS
Material
Thickness
Polymeric liner membranes: mils
Polyethylene (PE) 10
Polyvinyl chloride (PVC) 20
Butyl rubber 63
Chlorosulfonated polyethylene,
with fabric reinforcement 34
Ethylene propylene rubber (EPDM) 51
Chlorinated polyethylene (CPE) 32
Admix materials inches
Paving asphalt concrete 2.2
Hydraulic asphalt concrete 2.4
Soil cement 4.5
Soil asphalt 4.0
Bituminous seal 0.3
Emulsion asphalt on fabric 0.3
In addition to the primary membrane
specimens, 42 small secondary polymeric
specimens were buried in the sand for ex-
posure testing. They included membranes of
several additional polymers which are po-
tentially useful as liners, i.e., neoprene,
polypropylene, and polybutylene.
Refuse Characteristics
Approximately 12 tons of residential
refuse were ground over a period of a week
in an Eidal Mini-Mill Grinder (Model 100)
without classification. The shredded refuse
was delivered to the site in 3 loads and was
systematically loaded into the 24 generators
on a rotating basis.
About 950 pounds of refuse, having a
water content of 12 to 15%, were added to
each of the generators in 45 to 47 loads or
lifts. This amount is equivalent to 1150
pounds of refuse per generator of 30% water
content, or about 1240 pounds of refuse per
cubic yard at 30% water content.
Table 2 shows the composition of the
composite sample:
TABLE 2. COMPOSITION OF REFUSE
Material
Percent
Water 12.2
Paper 53.6
Cloth 0.8
Plastics and rubber 4.9
Wood, garden and food waste 5.1
Oils and fats 0.9
Metal 7.6
Glass, rock, and soil 14.9
Total 100.0
The content of identifiable food waste
was low. It is assumed that the refuse must
have been collected from a neighborhood where
most food wastes are flushed into the sewers
through sink disposal units. The actual
content of putrescible organic material was
somewhat higher than shown, as some pieces
of paper and plastics in the larger size
fractions were obviously saturated with fats,
blood, etc.
152
-------
MONITORING THE GENERATORS (3)
During the first year of exposure of
the liners to leachate (November 1974 - Nov-
ember 1975), monitoring the generators con-
sisted of the following:
1. Adding 2 gallons of tap water to
each generator on a biweekly basis. This
amount equals 1 inch of water per 2 weeks
or 26 inches per year.
2.
basis.
Collecting leachate on a biweekly
3. Measuring biweekly the ambient tem-
perature and the temperatures in the refuse
of 4 of the generators.
4. Analyzing, on a 4-week basis, the
leachate for the the following:
- Chemical oxygen demand (COD)
- pH
- Total solids
- Volatile solids
- Total volatile acids as acetic acid
(This was discontinued after 2 morths
and analyses were made of the indi-
vidual volatile acids.)
The temperatures observed in the refuse
of the 4 generators very closely equalled
ambient temperature (10 to 20 C). Tempera-
tures in the refuse exceeding ambient were
only observed during the first few days af-
ter the cells were loaded with refuse. By
the time the thermocouples had been placed
in the cells, the temperatures within the
cells had already dropped essentially to am-
bient temperature.
During the first year the method of col-
lecting the leachate was changed. Initial-
ly, the leachate was allowed to accumulate
in the cells and then drained. Consequent-
ly, the leachate ponded on the liners at
various heights, although efforts were made
by intermediate drainings to keep the height
between 1 and 2 feet. Later, "U" tubes
were installed at a height of 1 foot above
the liner surface and the leachate was
drained continually, leaving a head of 1
foot on the liners at all times. In making
this change the collection bags were changed
from polyethylene to polybutylene because of
the superior seams which could be obtained
by heat-sealing polybutylene. The polyethy-
lene bags failed at the heat-sealed seams
when keptunder constant stress and continuous
draining could not be performed with these
bags.
It was recognized early that a large
amount of organic acids was being generated
in the anaerobic decomposition of the refuse.
Several of these organic acids can interact
with organic materials such as the membrane
and asphaltic liners in the study; butyric
acids in particular have adverse effects on
many rubbery and plastic materials. Conse-
quently, analyses were made for individual
organic acids, as shown' in the analyses made
prior to dismantling the generators to re-
cover the liners exposed for one year to the
leachate (Table 3). Results of Breland (4),
who reported data on individual organic
acids, are also shown.
TABLE 3. ANALYSIS OF LBACHATE
Breland (4)
o
Ambient temperature, C
Total solids , %
Volatile solids
Nonvolatile solids
COD, g/1
pH
TVA, g/1
Organic acids
Acetic, g/1
Propionic , g/1
Isobutyric, g/1
Butyric , g/1
Consolidation of refuse
at 1 year, %
14
3.31
1.95
1.35
45.9
5.05
24.33
11.25
2.87
0.81
6.93
6
—
1.25
—
—
18.0
5.1
9.3
5.16
2.84
—
1.83
—
During the first year of monitoring the
cells, the leachate entered the bases below
the liners in only 3 of the cells. 2 of
these liners, soil asphalt and paving as-
phalt concrete, leaked whereas the leakage
in the third was caused by a failure of the
epoxy sealing compound around the periphery
of the specimen.
DISASSEMBLY OF GENERATORS
AND RECOVERY OF LINERS (3)
Twelve of the 24 leachate generators
and exposure cells containing the test lin-
er specimens were dismantled in November
1975 and the liner specimens recovered for
laboratory testing. This was done 52 weeks
153
-------
after the refuse in the columns had been
brought to field capacity and leachate be-
gan ponding on the liners.
The major problem faced in dismantling
the generators and recovering the exposed
liners was to perform the operations with-
out damaging the liner specimens. The in-
dividual filled columns weighed approxi-
mately 3000 pounds.
When the generators were dismantled,
the refuse was inspected and a photographic
record made. The appearance of the refuse
showed that it had deteriorated very little
during the course of the year. Pieces of
newspaper could be read and colors were re-
tained in both paper and pieces of fabric.
Organic material, leaves, twigs, etc., also
showed little damage. Pieces of plastic
and metal (aluminum, tin cans, pennies,
etc.) were little changed. However, pieces
of rubber, such as rubber bands, were high-
ly swollen and some pieces of what appeared
to be polyvinyl chloride, such as used in
wallets, had become extremely hard.
The moisture content of the refuse
taken from the generators was found to be
about 60%.
RESULTS OF ONE YEAR OF EXPOSURE
OF LINERS TO LEACHATE
Admixed Materials
The asphalt concrete and soil asphalt
liners lost drastically in their compressive
strength; however, they maintained their im-
permeability to leachate. The asphalt bind-
er, which normally hardens on aging in air,
became softer indicating possible absorp-
tion of organic components from the leach-
ate.
The soil cement lost some of its com-
pressive strength; however, it hardened
considerably during the exposure period and
cored like a portland cement concrete. It
became more impermeable during the exposure.
Inhomogeneities in the admix materials,
which probably caused the leakage in the
paving asphalt and soil asphalt liners, in-
dicate the need for considerably thicker ma-
terials in practice. Thicknesses of 2 to 4
inches were selected for this experiment to
give an accelerated test and were designed
with an appropriately sized aggregate. The
same compositions in the second set of 12
liners have not leaked after 27 months of
exposure to leachate.
The asphalt membranes withstood the
leachate for 1 year, although they did
swell slightly. There was no indication of
disintegration or dissolving of the asphalt.
Polymeric Membranes
The changes in the physical properties
of the polymeric membranes during the first
year of exposure to leachate are presented
in Table 4. Overall the change in the phy-
sical properties of the membranes was rela-
tively minor. They all tended to soften,
probably due to the absorption of leachate.
On the other hand, there was a substantial
loss in seam strength in the polyvinyl chl-
oride, the chlorosulfonated polyethylene,
and the chlorinated polyethylene liners.
The seam strength of the butyl and EPDM lin-
ers decreased less, but they had lower
strength prior to exposure. The polyethyl-
ene maintained the highest seam strength re-
flecting the fact that it was heat-sealed.
Of the 6 polymeric membranes, the poly-
ethylene film best maintained overall prop-
erties during the exposure period. It also
absorbed the least amount of leachate. How-
ever, this liner material has low puncture
resistance. The butyl and EPDM liners
changed somewhat more in physical properties
than did the polyethylene during the exposure
period. In particular, they maintained
their stress-strain properties and did not
soften; they retained their respective seam
strengths, but their original values were
low. The 3 remaining membranes, PVC, chloro-
sulfonated polyethylene, and CPE, were about
equal; they all tended to soften and lose
in hardness, tensile properties and in seam
strengths, even though they had good initial
values. These latter materials are all
thermoplastic and unvulcanized.
The fact that no leachate appeared be-
low the membrane liners during the year in-
dicates high impermeability. No test of
water permeability was made of the exposed
specimens; samples have been retained for
possible future tests. On the other hand,
related closely to the water permeability
of materials is their absorption of water.
The absorption can thus result in signifi-
cant swelling of a liner and a significant
increase in its permeability to water and
possibly to dissolved components.
154
-------
TABLE 4. EFFECT OH THE PROPERTIES OF POLYMERIC MEMBRMB LINERS
OF 1 YEAR OF EXPOSURE TO LEACHATE FROM SIMULATED SAUITAia LANDFILLS
(Data in U.S. Customary Units)
Exposure
Test time.
Item method years
Liner number —
Generator number —
Thickness, mils —
—
Tensile strength.
psi ASTM D412
Elongation at
break, » ASTM D412
Tensile set, t ASTM D412
S-200*, psi ASTM D412
Tear strength
(Die C) , ppi ASTM D624
Hardness (Duro
A - 10 sec.) ASTM 02240
Puncture resis- Fed. Std.
tanceb 101B, Method
2065
Force, Ib
Elongation, in.
volatiles at 105°C, %
Seams
Method of bonding
Peel strength.
ppi ASTM D413
Shear strength, ppi
—
—
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
1
—
0
1
0
1
Polyethylene
21
19
11-12
11
2145
2465
SOS
560
422
432
1260
1205
390
496
98
—
13.9
14.8
0.76
0.80
0.02
Beat
J
HS.6d
>10.3d'«
>20.2d
Polyvinyl
chloride
17
20
20-21
21
2580
2350
280
330
73
57
1965
1550
335
4 SO
76
64
25.8
30.1
0.69
0.70
3.55
Cement
4.0
5.1
>37.2d
>25.6d
Cbioro- Ethylene
Butyl sulfonated propylene
rubber polyethylene rubber
7
21
61-65
64
1435
1395
395
410
17
14
690
685
180
202
51
50.5
44.8
49.5
1.22
1.20
2.02
Cement
(LTV)C
3.8
2.9
3O.O
42.0
6
22
32-36
38
1765
1640
250
300
111
106
1520
1245
300
305
79
64
32.9
57.0
0.60
0.88
12.76
Cement
>30.0d
3.4
>50.0d
40.2
16
23
49-53
51
1475
1455
410
435
16
12
760
740
181
195
54
51.5
39.4
40.1
1.44
1.18
5.54
Cement
(LTV)C
2.5
2.0
14.5
24.3
Chlorinated
polyethylene
12
24
31-32
35
2270
1810
410
400
429
208
1330
1090
255
320
85
65.5
47.0
49.8
1.04
0.98
6.84
Solvent
10.0
5.1
>35d
'stress at 200% elongation
Rate of penetration of probei 20 inches per minute.
IJLow temperature curing cement.
Break in the specimen outside of seam.
8Seam in the polyethylene liner used in the steel columns;
short.
In Table 5 the water and leachate ab-
sorptions by various polymeric liner ma-
terials are presented. The data include
the water absorption after 1 year in water,
and leachate absorption after 1 year of ex-
posure. The materials which have shown the
lowest amount of swell are polyethylene,
polybutylene, and polypropylene, in which
cases the absorptions are a few tenths of a
percent, with the leachate being absorbed
slightly more than water. These results
would predict the low water transmission
which was observed for the polyethylene (3).
TENTATIVE CONCLUSIONS AFTER-
ONE YEAR OF EXPOSURE
One year of exposure to sanitary land-
fill leachate resulted in relatively minor
deterioration to most of the liner materials
which are being evaluated. In no case was
there a significant increase in water
tabs in the liner specimens mounted in base were too
permeability. Admixed materials, such as
soil asphalt and asphaltic concretes, lost
significantly in compressive strength, but
did not increase in pernsability. The pol-
ymeric membranes swelled and softened to
various degrees but did not become permeabls
These results indicate that substantially
longer exposures would be required to be
able to determine whether the liners would
become more permeable when in contact with
leachate.
The small amount of change which took
place in the properties of the liners after
one year of exposure indicates that an ad-
ditional year would have a minor effect up-
on properties. Therefore, the liners which
remain in the test should be exposed con-
siderably longer than the additional year
before being retrieved and tested. The
swelling of most of the polymeric materials
by the leachate would indicate a possible
155
-------
TABLE 5. WATER AND LEACHATE ABSORPTION BY POLYMERIC LINERS
(Data in percent absorbed by weight)
Butyl rubber
Chlorinated polyethylene (CPE)
Chlorosulfonated polyethylene
Ethylene propylene rubber (EPDM)
Neoprene
Polybutylene
Polyethylene
Polypropylene
Polyvinyl chloride
Liner
no.
7a
22
24
12a
13Sb
23
3
4S
6sa
14S
8
A
16
18
25
26
9
20
213
27
10
11
15
17a
1.9
Water-RT
1 year
1.60
1.70
1.10
13.10
19.60
15.50
17.40
18.00
9.20
11.20
1.40
4.80
—
1.50
1.60
22.7
0.25
0.20
0.28
1.85
1.85
2.10
1.85 .
0.60
Leachate
1 year
1.78
2.32
1.0
9.0
12.4
10.3
20.0
19.0
13.64
8.71
5.95
5.50
—
5.59
8.99
8.73
0.33
0.25
0.40
6.72
5.0
4.64
3.29
0.75
.Liners mounted in generator bases.
S = fabric supported liner.
loss in permeability over the longer expos-
ures. Many polymeric materials become in-
creasingly permeable on absorption of the
medium with which they are in contact. The
testing of permeability of swollen membranes
should be undertaken.
The variation in the swelling of poly-
meric liners, particularly, the polyvinyl
chloride, indicates a variation in composi-
tion which could be a significant factor in
the long term performance of a given liner.
It is concluded that a study should be in-
cluded of the composition of these liner
materials to determine the effect upon ex-
posure to leachate.
The method being followed in this pro-
ject to assess the various liner materials
is costly and time consuming and certainly
is not amenable to specifications
requirements. A more simple and more direct
test should be developed.
This project will supply information
regarding the effects of leachate on var-
ious liner materials on a relatively small
scale. Correlation of these results with
actual landfills is desired in order to as-
sess fully the performance of liner ma-
terials.
PLANS AND CURRENT WORK
In view of the above conclusions, the
project was modified to accomplish the fol-
lowing :
1. To extend the length of time that
the remaining liner materials now being ex-
posed to leachate from 24 months to 42
months. The properties of the liner
156
-------
materials in the test will thus be tested
after 1 year and 3.5 years of exposure to
landfill leachate.
2. To run supplementary exposure tests
of various liner materials including sever-
al new materials, e.g. elasticized polyole-
fin, polyester elastomer, unvulcanized EPDM,
etc., by immersion in leachate generated
and collected from the remaining 12 simu-
lated sanitary landfills.
3. To analyze the basic compositions
of the various polymeric membranes for pos-
sible use in establishing specifications.
4. To determine the permeability of
polymeric membrane liners to water and
leachate when swollen as well as when unex-
posed.
5. To develop simple methods for
evaluating materials for lining landfills
which could be used in setting up specifi-
cations.
Small specimens of a range of polymer-
ic liners are being immersed in the leach-
ate for up to 1,5 years in tanks of poly-
ethylene, such as shown in Figure 4, under
anaerobic conditions. These tanks are ar-
ranged in series with the leachate from the
generators combined and allowed to stream
slowly through the tanks. The specimens
are large enough for the tests used in the
primary evaluation, except for the seam ad-
hesion. Specimens will be removed and
tested at intervals.
LEACHATE OUT
^LEACHATE IN
YETHYLENE
TANK
LNER SPEOMENS
LINER IMMERSION TANK
As the permeability of a liner to wa-
ter and leachate is of primary importance
in its performance as an impervious barrier
at the bottom of a landfill, several test
methods are being used to determine this
property particularly of flexible membrane
liners. These methods include:
1. ASTM E96, Method BW, to determine
the moisture vapor transmission of liners.
2. Tests in a top-pressure permeameter
in which approximately 4 atmospheres of pres-
sure are being applied to specimens, both as
received and after swelling in water at 70 C
3. Immersion in distilled water of
sealed bags prepared from the flexible lin-
er materials and containing leachate. In
this test the pH and conductivity of the
distilled water are being monitored and the
weight of the bags is being measured at in-
tervals (Figure 5).
BAG OF LEACHATE
IMMERSED IN WATER
The primary exposure cells continue to
be monitored. There is a gradual change in
composition of the leachate; both volatile
and nonvolatile solids are decreasing, as of
February 1977, as are COD and organic acids.
The latter may be a reflection of the lower
ambient temperature. The refuse has consol-
idated 11% in the 27 months since it was
brought to field capacity in December 1974.
ACKNOWLEDGMENTS
The work reported in this paper was
performed under Contract 68-03-2134, "Eval-
uation of Liner Materials Exposed to Leach-
ate" with the Municipal Environmental Re-
search Laboratory of the Environmental Pro-
tection Agency.
The author wishes to thank Robert E.
Landreth for his support and guidance in
this project. The author also wishes to
thank Dr. Clarence Golueke and Stephen
Klein of the Sanitary Engineering Research
Laboratory, University of California, Berk-
eley, for their guidance with respect to
leachate generation and characterization.
157
-------
REFERENCES
1. Haxo, H.E., and R.M. White, First Inter-
im Report - EPA Contract 68-03-2134, "Eval-
uation of Liner Materials Exposed to Leach-
ate" , November 27, 1974.
2. Haxo, H.E., "Assessing Synthetic and
Admixed Materials for Lining Landfills,"
EPA Symposium, "Gas and Leachate from Land-
fills: Formulation, Collection and Treat-
ment", Rutgers University, March 1975, EPA
600/9-76-004 (March 1976).
3. Haxo, H.E., and R.M. White, Second In-
terim Report - EPA Contract 68-03-2134,
"Evaluation of Liner Materials Exposed to
Leachate", EPA-600/2-76-255, September 1976.
4. Breland, G.G., Jr. "Landfill Stabiliza-
tion with Leachate Recirculation, Neutrali-
zation, and Sludge Seeding," Special Re-
search Problem, Georgia Institute of Tech-
nology, School of Civil Engineering, (Sept.
1972).
158
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PREDICTING CADMIUM MOVEMENT THROUGH SOIL AS INFLUENCED
BY LEACHATE CHARACTERISTICS
D.F. O'Donnell, B.A. Alesii, J. Artiola-Fortuny,
and W.H. Fuller
Soils, Water and Engineering
The University of Arizona, Tucson, AZ 85721
ABSTRACT
Cadmium movement through soil can be expressed as a function of the physical
components of the system. An analytical solution to a partial differential equation was
fitted to data from soil-column experiments. The resulting coefficients are regressed
against readily measurable properties of the leachate. Results indicate that these co-
efficients (corresponding to travel rates of cadmium through soils) are highly related to
both total organic carbon content and total soluble ions of the carrier fluid. Migration
rates of Cd through different soils are tabulated with relevant characteristics of the
leachate, as a simplified, user-oriented predictive tool.
INTRODUCTION
THE MODEL
To develop confident guidelines for
disposal of potentially hazardous metal-
containing wastes, a knowledge of a multi-
tude of microenvironmental factors influ-
encing metal migration rates is necessary.
Research identifying some soil and leachate
factors has been published by Fuller et al.
(1976a,b), and Korte et al. (1976) report
metal movement as influenced by soil physi-
cal and chemical properties. Leachates of
varying properties affect the movement of
certain metal ions through clay mineral
systems according to Griffin et al. (1976)
and Folsom et al. (1976). This paper
attempts to investigate the effect of
interaction pf soils and leachate prop-
erties on Cd movement. Fuller (1977)
suggested that the major solution prop-
erties of the leachate affecting metal
attenuation are (a) total organic carbon
content (TOC) and (b) total soluble ion
(ION) concentration. Predictions of.Cd
movement are based on a regression analysis
because models based on chemical reactions
have rarely been successful.
The model assumes Cd movement in
soils is described by the Lapidus and
Amundson (1952) model. The theoretical
curves approximately describing Cd trans-
port in soil columns, under saturated
steady flow conditions are matched with
actual data. Because of the nonlinearity
of the mathematical description, a slightly
different approach to parameter estimation
is taken. The results of the parameter
estimation procedure are regressed with
readily measurable soil-leachate system
properties. Each of these coefficients
correspond to a particular migration rate
for Cd. To facilitate management use, the
results of the regression analysis and rate
calculations are tabulated.
The equation used for describing Cd
transport, under saturated steady flow
conditions, is
3z 3t
(1)
where
c = Cd concentration in solution (pg/cm3)
159
-------
n = amount of Cd sorbed per unit volume of
soil (yg/cm3)
D = dispersion coefficient (cm2/day)
V = pore water velocity (cm/day)
t = time (day)
z = distance in soil (cm)
a = fractional void volume in soil
The -r— term does not include plant up-
take, microbial degradation or chemical
transformations. The mathematical descrip-
tion of the absorption mechanism is an
empirical one. The mechanism may be approx-
imated as a first order kinetic reaction by
and
£-V-
(2)
The parameters K.. and ^ are forward and
backward reaction rate constants (day"1),
respectively.
The additional relations:
c = Co , when z = 0, t > 0 (3a)
n = 0
} , when t = 0, z > 0
(3b)
describe input concentrations and initial
conditions of the soil.
Equations (1), (2), (3a) and (3b)
describe traveling wave movement in semi-
finite columns where side influences are
ignored. This model and its solution was
presented by Lapidus and Amundson (1952) .
Similar models to describe chemical move-
ment in soils have also been presented by
Oddson et al. (1970), and Lindstrom et al.
(1971). Davidson and McDougal (1973)
noted that the ability of the above models
to describe experimental data has not been
adequately determined.
The solution to (1) and (2) with
boundary conditions (3a) and (3b)' as pre-
sented by Lapidus and Amundson (1952) is:
c(t) = e2D[F(t)
where F(t) =
F(t)dt]
(4a)
/I [2/KlKzX ^)
dx
(4b)
4D + a ~ K2*
(4c)
Unfortunately no precise prior know-
ledge exists for the parameters D, K^ and
K£. The best estimates of these are ob-
tained by comparisons of calculated curves
for various sets of parameters D, K^ and K£
with actual data. Curves for finite column
lengths are found by restricting z to fixed
values.
Since our approach to estimating
these parameters is slightly out of the
ordinary, we present the steps in some
detail.
PARAMETER ESTIMATION
Reactive solute movement in soil col-
umns appears to be variable in nature.
Precise replication of data from such ex-
periments is never achieved. Uncontrolled
variables such as soil packing, irregular
and irreproducible pore geometryjand
trapped gases often account for slight var-
iations in experimental breakthrough
curves. The first step is therefore mea-
surement of the ability to reproduce data
from column experiments.
Replicate column experiments using Ava
si.c.l. and leached with 100 ppm Cd in
solution with three natural municipal
leachates. Table 1 summarizes the error
estimates from these studies. In all sub-
sequent column studies the experimental
error was assumed to be approximately 3%.
The parameters to be estimated in
equation (4a), (4b) and (4c) are D, KI and
K£. Theoretical curves are matched with
experimental data by use of an iterative
nonlinear least squares procedure (Davidon,
1959). The sum of squares may be thougit as
a measure of the difference between theo-
retical breakthrough curves and experiment-
al data. This can easily be translated to
an average distance,
-------
For example, assume the experimental
error is 3.0% and also that 15 data points
are given. [.Data points were generated by
p(t) = c(t) + e, where c(t) is given by
equation (4) with z = 10 cm, V = 3.6 cm/day,
a = 0.474, D = 2.0 cm2/day, Kj = 7.0 day"1,
"1
K2 = 15.0 day" and
.0, 0.5)]. As
discussed previously, the data points are
satisfactorily approximated by a break-
through curve whenever the average distance
between the two is less than 3.0%. Figure
1 is a rough approximation of a small por-
tion of the sum of squares surface for this
example. It is possible to approximate the
bottom portion of this surface with a
straight line segment. Figure 2 is a graph
of a few points on the bottom of this sur-
face and the best fitting line. Figure 3
shows breakthrough curves calculated from
parameters lying on the bottom of the sur-
face in Figure 1. These curves all approx-
imate the data points within the experi-
mental error.
10.4 r
8.4-
Figure 2.
4.0
8.0
12.0 16.0 20.0 24.0
K2
Linear approximation to points
of least height on the bottom of
Figure 1 showing K-, K_ relation-
ship.
Figure 1. Small section of sum of squares surface for D = 2.0 cm /day.
161
-------
TABLE 1. ESTIMATES OF REPRODUCIBILITY FOR SOIL COLUMN EXPERIMENT
Soil
Column Type
Flux
(Av.)
No. of
Leachate Source Replicates
cm/ day
1 Ava s i . c . 1 .
2 Ava si. c.l.
3 Ava s i . c . 1 .
5.
7.
6.
9
2
7
New
25%
Old
leachate
(ID
of new (II)
leachate
(I)
4
3
3
Average
Reducibility
ppm
3.
5.
3.
3
7
2
The location of the global minimum on
the sum of squares surface followed no
definite trend. The above procedure was
introduced to alleviate this problem.
Moreover every column experiment generates
a unique line segment. These segments
have a definite trend; fast migration rates
have much smaller slopes than slower migra-
tion rates.
The nonlinearity of the parameters K-^
and K? in equations (4a), (4b), and (Ac)
prevents a direct translation of the slope,
Kj/K.2, into flow rates. This problem is
solved by regressing the approximate end-
points of the line segments with TOC and
ION. The dispersion coefficient, D, gen-
erally increased as the absolute value of
the pair of reaction coefficients (Ki,K2),
increased along a line segment. A single
dispersion coefficient for each soil is
obtained by averaging all the calculated
coefficients along each line segment and
tabulating an average for all these
segments. The flow rates for each slope
are then calculated as the average of the
flow rates for each of the endpoints.
This approach greatly simplified the table
construction.
EXPERIMENTAL DESIGN
segments. Figure 4 is an illustration of
the variation in line segment slopes for
some actual soils, while Figure 5 shows a
variation in slopes with selected leachates.
1.4
1.2
-o- 2.5 5.0
—a— 7.0 15.0
-o- 8.1 18.1
0.9 1.6 2.3 3.0 37 44
PORE VOLUME
Figure 3. Calculated breakthrough curves
for single line segment, D =
2.0 cm2/day.
PROCEDURE
A factorial experiment was designed
to measure the effects of various attri-
butes of the leachate on Cd migration.
Each soil was to be leached with Cd-
spiked leachate under four levels of ION
(inorganic ions ). If a particular fac-
tor of the leachate significantly influ-
ences the migration rate for Cd, it will
also cause a variation in the slopes of
the calculated line segment for differing
values of this factor. These factors are
regressed with the slopes of the line
The soil column procedures have been
described by Fuller et al. (1976a) and
Korte et al. (1976). In brief, 10-cm
lengths of 5 cm PVC pipe were uniformly
packed with soil to form a vertical soil
column of known density. Soils represent-
ing major soil orders were collected from
"benchmark" locations through the USA.
Natural municipal landfill leachate
"spiked" with 100 ppm Cd was displaced
through the soil columns under strict,
162
-------
47. a
25 4.5 6.5 8.5 10.5 125
12.0
Figure 4. Variation in line slopes as Figure 5.
influenced by three soils.
Variation in line slopes as
influenced by leachates in
Anthony sandy loam.
saturated, anaerobic conditions at known
fluxes controlled by use of precision peri-
staltic pumps. Influent and effluent dis-
placements caught in a fraction collector
were analyzed for TOG, inorganic salt, Cd,
Fe by standard procedures previously
described (Fuller et al., 1976, and Korte
et al. 1976a).
Two different sources of leachate were
used. One, 3-4-year old solution of low
constituents concentration (Fuller et al.,
1976) and 1^-2-year old of relatively high
constituent concentration (TOG, EC, Fe,
etc.)(Fuller et al., 1976).
The latter leachate was diluted to 0,
25 and 50% of original concentration with
deionized water as a necessity to evaluate
effects of TOG, and inorganic ion concen-
trations on Cd migration rates through
soils.
The pore volumes of Wagra'm loamy sand
(low in clay, 4%), Anthony sandy loam (in-
termediate in clay, 15%), and Fanno clay
(relatively high in clay, 46%) were dis-
placed with four leachates having four
levels of TOC of 0.01, 0.18, 0.50, and 1.0%
until breakthrough of Cd occurred (i.e.,
C/Co = 1) or until 20 pore volume was col-
lected. This same procedure was followed
for evaluating the effect of Fe levels
(100, 500, and 1,000 ppm) and inorganic
levels (342, 1,013, and 2,163 ppm) on Cd
attenuation at different TOC levels. The
varying iron levels were obtained by "spik-
ing" the leachate with desired concentra-
tion of FeCl, whereas the salt levels were
established by "spiking" each leachate used
with various salts (CaCl2, Kg (1^3) 2» NaCl,
and KC1) to give the desired concentration
at the same cation ratio as the natural
landfill leachate.
RESULTS AND DISCUSSION
Line segments calculated from column
experiments were regressed against both
TOC and ION. The competitive ion term is
assumed to be the sum of the soluble ions
in solution, Fe, Mn, Ca, Na, and K. High
correlations were reached with both of
these terms on Anthony sandy loam and Fanno
clay. Wagram loamy sand did not show high
correlations with either property. How-
ever, this may be expected. Wagram loamy
sand contained only 4% clay-sized particles.
Table 2 is a summary of the correla-
tion coefficients for the slope of the line
segment against the terms TOC and ION. The
negative quantities indicate Cd transport
rates increase as TOC and ION increase.
163
-------
The leachate's influence on Cd
transport is discussed separately for each
soil listed in Table 2. The soil's clay
content is given for reference purposes.
TABLE 2. CORRELATION FOR THREE SOILS AND
TOTAL ORGANIC CARBON (TOC) AND
TOTAL INORGANIC ION CONCENTRATION
(ION)
Soil
Wagram 1. s.
Anthony s.l.
Fanno c.
Clay-<2p| TOC
%
4 -0.203
15 -0.928
46 -0.903
I ION
-0.150
-0.922
-0.994
Tables 3 through 8 summarize the infor-
mation obtained to date and indicate the
approach that will be used to bridge the
gap between the simulation model and field
application. A regression equation for the
slope (K]_/K2) of the line segment is devel-
oped in the form:
Slope = (D x Factor) + (E x Factor) + ----
where the letters D, E, --- H are numerical
coefficients and the Factors are measurable
properties of the leachate (eg. TOC and ION).
The users will insert the factor informa-
tion for a particular situation to arrive
at a value for slope applicable to their
situation. The tables list contaminant
movement rates for each slope and relative
concentration (C/CQ) . Using Table 3 as an
example, suppose a user has a waste that
is releasing 2.0 ppm cadmium (Co) in its
leachate and 0.4 ppm cadmium (C) is the
concentration limit in the soil solution
below the disposal site. Then the user is
concerned about the relative concentration
0.2 (C/C0 = 0.4 ppm/2.0 ppm = 0.2). Sup-
posing, additionally, that using measured
properties of the leachate the user has
calculated the slope to be 0.12, then Table
3 shows that the migration rate of the cad-
mium will be about 33.7 cm/day. If the
critical concentration limit in the soil
solution was, instead, 1.2 ppm, then the
relative concentration would be 0. 6 and the
migration rate would be 26. 7 cm/day.
Wagram loamy sand; The low correla-
tions may be expected for Wagram l.s.
since it is a very loose, highly siliceous
sand (88%) with only 4% secondary clay
mineral. For widely varying leachates
there were only slight differences in ob-
served breakthrough curves. Some changes
were within experimental error. The only
notable difference in Cd breakthrough
curves occurred between the leachate with
13,010 ppm TOC, and 2,762 ppm ION, and the
leachate whose characteristics are 116 ppm
TOC and 428 ppm ION. Cd under the former
reached breakthrough at 2.43 pore volumes,
while Cd with the latter leachate reached
breakthrough after 3.56 pore volumes.
These two leachates represent the highest
and lowest levels of both TOC and ION for
a Wagram carrier fluid. The line segment
slopes for these two leachates were 0.1010
and 0.1250, the more "potent" leachate
having the lower slope. Some intermediate
levels of TOC and ION produced line segment
slopes which were outside the range given
by the highest and lowest levels.
An initial estimate of the relation-
ship between slope with TOC and ION concen-
tration is:
Slope = -9.48xlO~6x(TOC ppm)-6.36xlO~5x
(ION ppm) + 0.15 (5)
Tables 3 and 4 are tabulated flow rates for
various values of slope given by equation
(5) for solution speeds of 37.40 cm/day
(fast) and 9.35 cm/day (slow), respectively.
The dispersion coefficient for these tables
is 19.50 cm2/day, and the fractional void
volume is 0.350. The range of tables 3 and
4 encompasses all observed slopes in the
experiments.
Both equations (5) and Tables 3 and 4
indicated Cd movement in Wagram l.s. is
extremely rapid. Furthermore Cd can move
through saturated Wagram soil at velocities
higher than the carrier fluid. For a slope
of 0.01 the leading edge travels at approx-
imately 42.66 cm/day with a carrier fluid
velocity of 37.40 cm/day. This phenomenon
is also pronounced at lower velocities (see
Table 4). It should be noted that these
velocities are calculated from the total
volume of solute per day divided by the
void volume per centimeter of soil column.
Anthony sandy loam; Cd movement in
this soil changed radically with leachate
characteristics. For leachate components
of 10,510 ppm TOC and 2,300 ppm ION, Cd
breakthrough was recorded at 6.53. pore vol-
umes. Only 60% of initial concentration
164
-------
was measured in the column effluent at
25.04 pore volumes for a leachate whose
characteristics are 105 ppm TOC and 398 ppm
ION. At low levels of TOC, the ION effect
was most noticeable. For instance, 60% of
initial Cd concentration was achieved at
14.60 pore volumes with a leachate of 105
ppm TOC and 1^398 ppm ION.
Slope of the computed line segment also
changed with leachate characteristics. The
result of the regression analysis for
Anthony s.l, is:
Slope = -1.67xlO~4x (TOC ppm)-7.66xlO~4x
(ION ppm) +4.59
(6)
Tables 5 and 6 are tabulated Cd transport
rates for corresponding slopes at flow
rates of 10.047 cm/day (slow) and 40,19 cm/
day (fast), respectively. These tables span
the range of observed line segment slopes
from experimental data. The dispersion co-
efficient and fractional void volume for
both of these tables are 13.58 cnn/day and
0.333, respectively.
The average slope for column experi-
ments with Anthony s.l. is 2.19. This
corresponds to the leading edge travel
rates of 1.89 cm/day and 6.62 cm/day in
slow and fast carrier fluid rates, respec-
tively. It is interesting to note from
Tables 5 and 6 that Cd transport rates are
lower than carrier fluid rates for all
levels of leachate constituents. Table
entries of 0.0 indicate that particular
concentration of Cd calculated from equa-
tion (4a) was not reached in 45 days. This
may be due to insufficient accuracy in the
numerical integration.
Fanno clay: Transport of Cd in vari-
ous leachates through Fanno c. behaved in
a similar manner to Anthony s.l. However,
the flow rates for Cd were appreciably
lower than in Anthony. At high levels of
TOC the effect of ION concentration was
apparent but not as great as at lower
levels of TOC.
The result of regression of slope with
TOC and ION concentration is:
Slope = -6.22xlO~5x(TOC ppm)-2.03xlO~3x
(ION ppm) + 6.69
(7)
Tables 7 and 8 tabulate Cd flow rates for
various slopes at solution speeds of 6.76
cm/day (slow) and 27.06 cm/day (fast). The
coefficient and fractional void volume for
both tables are 9.67 cm2/day and 0.495,
respectively.
Some regression difficulty was encoun-
tered during the table construction for
Fanno c. For this reason these tables
were built to include slopes only up to
4.7. Further column experiments are under-
way to hopefully correct this situation.
These tables do include most of the ob-
served line segments to date.
Tables 7 and 8 show Cd movement is
considerably slower in Fanno c. than in
both Wagram and Anthony s.l.
In Fanno c., Cd travel rates are not
greater than carrier fluid rates. The
average slope observed for Fanno clay was
3.18. The leading edge travel rate of Cd
concentration for this slope is approxi-
mately 1.25 cm/day for slow solution speeds
and 4.55 cm/day for fast solutions.
CONCLUSIONS
While equations 5, 6, and 7 do ade-
quately approximate present experimental
results, insufficient data have been col-
lected for any general predictions of Cd
transport in soils and the results pre-
sented in this paper should be taken as
preliminary. The results to date are con-
sistent with previous work showing the
effect of leachate organic content and
ionic strength on solute movement in soils.
Additionally, it appears that it will be
possible to develop simple and effective
user-oriented tools for predicting contami-
nant movement in soils to improve the
selection and operation of disposal sites.
ACKNOWLEDGMENTS
We wish to thank Jlary Schreiner for
her patience and effort in typing this
paper.
This research was supported in part by
the U.S. Environmental Protection Agency,
Solid and Hazardous Waste Research Divi-
sion, Municipal Environmental Research Lab-
oratory, Cincinnati, OH, from Grant No. R
803-988 and the University of Arizona,
165
-------
Soils, Water and Engineering Department.
Paper No. 2731 .
REFERENCES
Davidon, W.C. 1959. Variable metric
method of minimization. ANL-5990
(Argonne National Laboratory, U.S.
AE(TResearch and Development Report.)
Davidson, M.M. and J.R. McDougal. 1973.
Experimental and predicted movement of
three herbicides in a water saturated
soil. J. Environ. Quality 2:428-433.
Folsom, Jr., B.L., J.M. Brannon, and A.J.
Green, Jr. 1976. Field survey of
solid waste disposal sites: A pre-
liminary report. In: Residual Man-
agement by Land Disposal. Proceedings
of the Hazardous Waste Research Sym-
posium, February 2-4, 1976, Tucson,
Arizona. Wallace H. Fuller, ed. EPA-
600/9-76-015, U.S. Environmental Pro-
tection Agency, Cincinnati, OH. 1976.
280 pp.
Fuller, W.H. 1977. The importance of soil
attenuation for leachate control. U.
S. Environmental Protection Agency Of-
fice of Solid Waste Management Pro-
grams. Wash. D.C. 20460 (in press).
Fuller, W.H., C.M. McCarthy, B.A. Alesii,
and E.E. Niebla. Liners for disposal
sites to retard migration of pollut-
ants. In: Residual Management by
Land Disposal. Proceedings of the
Hazardous Waste 'Research Symposium,
February 2-4, 1976a, Tucson, AZ. W.H.
Fuller, ed. EPA-600/9-76-015, U.S.
Environmental Protection Agency, Cin-
cinnati, OH. 280 pp.
Fuller, W.H. and N.E. Korte. Attenuation
mechanisms of pollutants through soils.
In: Gas and Leachate from Landfills,
Formation, Collection and Treatment
Proceedings of a research symposium,
March 25-26, 1975b, New Brunswick, N.
J. L.J. Genetelli and J. Cirello,
eds. EPA-600/9-76-004. U.S. Environ.
Protection Agency, Cincinnati, OH.
1976. 196 pp.
Griffin, R.A., R.R. Frost, and N.F. Shimp.
1976. Effect of pH on removal of
heavy metals from leachates by clay
minerals. In: Residual Management by
Land Disposal. Proceedings of the Haz-
ardous Waste Research Symposium, Feb.
2-4, 1976, Tucson, AZ. Wallace H.
Fuller, ed. EPA-600/9-76-015, U.S. En-
viron. Protection Agency, Cincinnati,
OH. 1976. '280 pp.
'Korte, N.E., J. Skopp, W.H. Fuller, E.E.
Niebla, and B.A. Alesii, 1976. Trace
element movement in soils: Influence
of soil physical and chemical proper-
ties. Soil Sci. 122(6):350-359.
Lapidus, L., and N.R. Amundson. 1952. Math-
ematics of adsorption in beds. VI. The
effects of longitudinal diffusion in
ion exchange and chromatographic col-
umns. J.Phys. Chem. 56:984-988.
Lindstrom, F.T., L. Boersma, and Stockard.
1971'. The theory on the transport of
previously distributed chemicals in a
water saturated sorbing porous medium.
Soil Sci. 111:192-199.
Oddson, J.K., J. Letey, and L.V. Weeks.
1970. Predicted distribution of organ-
ic chemicals in solution and adsorbed
as a function of position and time for
various chemicals. Soil Sci. Soc.
Amer. Proc. 34:412-417.
166
-------
TABLE 3. CADMIUM TRANSPORT RATES (cm/day) IN WAGRAM SAND FOR A SOLUTION SPEED
OF 37.40 cm/day.
0.01
0.02
0.03
0.04
* 0.05
K 0.06
Id
s 0.07
o
w 0.08
CO
0.09
w
a °-10
M
0.12
PM
o 0.13
„ 0.14
eu
0.15
iJ
0.17
0.18
0.19
0.20
0.2
42.66
42.13
40.63
39.92
39.23
38.56
37.64
36.57
36.05
35.55
34.59
33.68
33.68
32.82
32.00
31.21
31.21
30.11
29.25
29.25
0.4
37.92
37.30
36.11
35.55
34.47
33.96
33.24
32.40
32.00
30.84
30.11
29.76
28.76
28.44
27.82
27.23
26.66
26.59
26.25
25.60
0.6
34.56
33.96
32.97
32.05
31.60
30.34
29.76
29.09
28.44
27.82
27.23
26.66
25.60
25.00
25.09
24.61
24.15
23.27
22.75
23.27
0.8
31.75
30.75
29.94
29.17
27.75
27.75
26.66
26.12
25.60
25.09
24.61
24.15
23.27
22.85
22.06
22.06
21.33
21.33
20.89
20.48
0.9
29.68
28.44
28.44
27.08
25.85
25.85
24.61
24.61
24.61
22.85
22.85
22.06
22.06
21.33
21.33
20.64
20.00
19.69
18.96
18.96
LSlope = -9.48 x 10 6 x (TOG) -
6.36 x -10 5 x
(ION) + 0.15
167
-------
TABLE 4. CADMIUM TRANSPORT RATES (cm/day) IN WAGRAM SAND FOR A SOLUTION SPEED
OF 9.35 cm/day
H
H
2
W
a
o
W
W
W
a
H
-3
O
14
P4
O
.J
w
0.2
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.13
0.14
0.15
0.16
0.17
0.18
0.19
0.20
12.82
12.82
12.43
12.07
11.72
11.72
11.40
10.80
10.80
10.80
10.26
10.01
10.01
9.54
9.32
9.32
9.32
8.92
8.92
8.92
0.4
10.26
10.01
9.77
9.54
9.32
9.12
8.92
8.55
8.37
8.37
8.20
8.04
7.74
7.60
7.46
7.32
7.32
7.07
6.95
6.84
0.6
8.55
8.37
8.04
7.89
7.74
'7.60
7.46
7.32
7.07
6.95
6.84
6.61
6.61
6.41
6.21
6.03
5.86
5.70
5.70
5.54
0.8
7.07
6.84
6.84
6.41
6.21
6.21
6.03
6.03
5.70
5.40
5.40
5.40
5.26
5.13
5.13
5.13
4.88
4.66
4.66
4.66
0.9
6.41
6.41
6.41
5.70
5.40
5.13
5.13
5.13
5.13
5.13
5.13
5.13
4.46
4.27
4.27
4.27
4.27
4.27
4.27
4.27
LSlope = -9.48 x!0"6x (TOC) - 6.36 x 10~ 5 x (ION) + 0.15.
168
-------
TABLE 5. CADMIUM TRANSPORT RATES (cm/day) FOR ANTHONY s.l. FOR A SOLUTION
SPEED OF 10.047 cm/day.
c/c0
0.2
0.3
0.6
0.9
1.2
1.5
H
ia *
w
X 2.1
o
2.4
CO
2.7
w 3.0
3
M 3.3
3.6
o 3.9
4.2
w
CM 4.5
o
^ 4.8
to
5.1
5.4
5.7
6.0
6.27
4.60
3.95
3.03
2.47
2.21
1.89
1.73
1.51
1.39
1.26
1.22
1.12
1.00
0.94
0.89
0.84
0.82
0.82
0.80
^lope = - 1.67
0.4
5.59
3.88
2.71
2.39
2.03
1.71
1.53
1.40
1.14
1.12
1.03
0.95
0.89
0.77
0.71
0.70
0.70
0.70
0.70
0.70
x 10~4 x (TOC)
0.6
5.05
3.35
2.14
2.02
1.72
1.43
1.34
1.17
1.01
0.94
0.88
0.81
0.68
0.60
0.58
0.50
0.50
0.50
0.42
0.42
- 7.61 x
0.8
4.60
2.89
1.84
1.72
1.41
1.14
1.19
0.99
0.87
0.79
0.76
0.68
0.47
0.00
0.00
0.00
0.00
0.00
0.00
0.00
10~4 x (ION)
0.9
4.14
2.63
• 1.61
1.43
1.41
1.36
1.23
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
+ 4.59
169
-------
TABLE 6. CADMIUM TRANSPORT RATES (cm/day) IN ANTHONY s.l. FOR A SOLUTION
SPEED OF 40,19 cm/day.
t-H
H
a
pa
X
o
w
w
w
H
tn
O
H
PH
O
J
CO
0.2
0.3
0.6
0.9
1.2
1.5
1.8
2.1
2.4
2.7
3.0
3.3
3.6
3.9
4.2
4.5
4.8
5.1
5.4
5.7
6.0
25.23
18.05
13.70
10.80
9.12
7.60
6.62
5.95
5.26
5.13
4.66
4.30
3.95
3.71
3.45
3.34
2.99
2.84
2.64
2.53
C/Co
0.4
22.49
15.36
11.42
9.33
7.74
6.62
5.78
5.13
4.56
4.36
3.95
3.66
3.41
3.10
2.91
2.71
2.58
2.47
2.37
2.37
0.6
19.89
13.54
10.07
8.20
6.84
5.86
5.26
4.56
4.10
3.73
3.42
3.12
2.87
2.71
2.59
2.53
2.42
2.37
2.23
2.14
0.8
17.83
11.69
8.78
7.33
6.22
5.26
4.66
4.10
3.73
3.20
2.93
2.71
2.52
2.43
2.47
2.37
2.37
2.19
1.96
1.67
0.9
16.16
10.72
7.78
6.41
5.70
4.88
4.27
3.80
3.66
3.02
2.70
2.62
2.44
2.51
2.37
2.37
2.19
1.89
1.49
1.19
Slope = - 1.67 x 10~4 x (TOC) - 7.61X io~4 x (ION) 4- 4.59
170
-------
TABLE 7. CADMIUM TRANSPORT RATES (cm/day) IN
6.76 cm/day.
FANNO c. FOR A SOLUTION SPEED OF
H
^
2:
w
S3
e>
w
C/l
w
a
M
^
F*
0
Hi
o
CO
0.2
0.235
0.470
0.705
0.940
1.175
1.410
1.645
1.880
2,115
2.350
2.585
2.820
3.055
3.290
3.525
3.760
3.995
4.230
4.465
4.700
5.39
4.10
3.25
2.73
2.33
2.09
1.85
1.67
1.52
1.45
1.34
1.35
1.25
1.19
1.04
0.98
0.93
0.86
0.81
0.76
1Slope = - 6.22 x
c/c0
0.4
4.82
3.60
2.93
2.44
2.09
1.83
1.67
1.48
1.34
1.26
1.16
1.09
1.05
0.95
0.85
0.80
0.74
0.72
0.70
0.62
10~5 x (TOO)
0.6
4.36
3.30
2.62
2.18
1.93
1.68
1.48
1.34
1.22
1.14
1.01
0.93
0.89
0.83
0.71
0.63
0.60
0.60
0.54
0.51
- 2.03 x 10
0.8
4.02
3.01
2.44
2.01
1.70.
1,53
1.36
1.17
1.10
1.03
0.82
0.80
0.78
0.78
0.53
0.43
0.48
0.48
0.42
0.42
3 x (ION) H-
0.9
3.66
2.84
2.33
1.83
1.60
1.39
1.26
1.06
1.10
1.06
0.00
0,00
0.00
0.00
0.00
0.00
o.oo
0.00
o.oo
o.oo
6.69
171
-------
TABLE 8. CADMIUM TRANSPORT RATES (cm/day) FOR FANNO c. FOR A SOLUTION SPEED
OF 27.06 cm/day.
H
2
H
a
o
H
CO
W
a
H
tJ
Pd
0
w
PN
0
^
0.2
0.235
0.470
0.705
0.940
1.175
1.410
1.645
1.880
2.115
2.350
2.585
3.820
3.055
3.290
3.525
3.760
3.995
4.230
4.465
4.700
22.49
17.10
13.24
11.09
9.54
8.21
7.33
6.62
6.03
5.57
5.03
5.13
4.55
4.27
4.02
3.87
3.55
3.45
3.25
3.07
C/C0
0.4
19-. 54
14.66
11.73
9.77
8.38
7.33
6.51
5.86
5.33
4.93
4.57
4.27
3.94
3.79
3.53
3.30
3.16
2.95
2.84
2.70
0.6
17.46
13.03
10.52
8.92
7.60
6.73
5.95
5.40
4.89
4.50
4.07
3.83
3.53
3.36
3.15
2.97
2.77
2.71
2.53
2.47
0.8
15.49
11.73
9.33
7.89
6.84
5.86
5.40
4.89
4.46
4.00
3.77
3.37
3.11
2.93
2.77
2.63
2.53
2.42
2.37
2.23
0.9
14.66
10.80
8.92
7.33
6.41
5.70
5.13
4.66
4.10
3.77
3.56
3.20
2.85
2.85
2.56
2.56
2.47
2.37
2.28
2.03
Slope i - 6.22 x 10~5 x (TOC) - 2.03 x 10~3 x (ION) +6.69
172
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ANALYTICAL METHODS FOR LEACHATE ANALYSIS
Richard A. Games
U.S. Environmental Protection Agency
26 West St. Clair Street
Cincinnati, Ohio 45268
ABSTRACT
Several studies have included the various methods of analysis applied to sanitary
landfill leachate. The first such report was a compilation of information available in
the literature and from various active researchers in the field. The State of Illinois
developed a similar document for monitoring landfill leachate in Illinois. The Canadian
Government has developed a document presenting their analytical protocol also.
Although different analytical methods can be used to determine any specific parameter,
the methods least subject to interferences should be chosen for leachates. Further re-
search is necessary in analyzing variable strength leachate and leachates from different
geographic locations.
Presently the Disposal Branch of the Solid and Hazardous Waste Research Division of
the Municipal Environmental Research Laboratory (MERL) is sponsoring a "Round Robin"
study on leachate analysis in order to get a better idea of precision and accuracy of
selected methods. Additionally the Division has two on-going studies for evaluating
methods applicable to hazardous waste analysis. These presently involve gross separation
schemes with more refined analytical methodology to follow.
COLLECTION/STORAGE
The collection, transport, storage,
and analysis of leachates is a very diffi-
cult task, if not downright frustrating.
Leachate can be collected from subsur-
face soil strata by using wells or piezo-
meters placed in drilled holes. Leachate
can also be collected above ground as it
appears in springs or at the toe of a land-
fill, but commonly these samples contain
eroded soil or may have reacted somewhat
with the soil. Leachate may also reach the
surface and enter surface waters via
groundwater discharge. In this instance
dilution plays a significant role in the
chemical characteristics.
The gross chemical characteristics of
leachate can be affected by the methods and
materials used during sampling. Most re-
searchers who have reported (1), (2), (3)
indicate that a plastic container indi-
cate that a plastic container is the
collection vessel of choice. When collec-
ting leachate in the field anaerobicallv,
Streng (3) recommends the use of polyethlene
containers. Further, Streng recommends
polyethylene containers produced by a high
pressure, non-catalyzed process. Chian
and DeWalle (1) recommend polyethlene con-
tainers when analyzing heavy metal content
collected leachate. Glass collection con-
tainers should be reserved for analysis of
only those parameters where no absorption
and/or adsorption can occur.
The storage of collected leachate is
generally accomplished by refrigeration at
4°C in tightly stoppered containers. All
researchers recommend certain analyses be
made immediately as samples may be altered
during storage under any conditions. Such
analyses include those for oxidation-re-
duction potential (ORP), color, turbidity,
suspended solids (SS), pH, and conductivi-
ty. Other parameters such as Chemical
Oxygen Demand (COD) and organic nitrogen
173
-------
may also vary after sampling, but such
changes can be reduced if the sample is
acidified and stored at 4°C. Most re-
searchers agree that storage times and con-
ditions must be identified when reporting
results.
ANALYTICAL PARAMETERS
The choice of parameters for leachate
analyses should be based on the probability
of detection of each parameter in the
leachate (known as indicator parameters),
as well as whether water quality standards
exist for the parameter. To a certain
extent, the type of waste at a given site
also has a bearing on the selected para-
meters. Heavy metals and certain trace ele-
ments are normally included in the analysis
of leachate because of their potential
health hazards.
When a large number of samples must be
analyzed, it is not feasible, or cost effec-
tive, to measure all parameters. As a rule
of thumb those that can be done easily
should be done initially. In their com-
prehensive study, Chian and DeWalle meas-
ured the following pollution parameters:
o PHYSICAL PARAMETERS -- pH, ORP, con-
ductivity, residue (total solids, TS;
volatile solids, VS; dissolved solids,
DS; and suspended solids, SS).
o INORGANIC CHEMICAL PARAMETERS ~
chloride, sulfate, phosphate, alka-
linity and acidity, nitrate, nitrite,
ammonia, sodium and potassium, cal-
cium and magnesium, hardness, heavy
metals.
0 ORGANIC CHEMICAL PARAMETERS -- COD,
TOC, volatile acids, tannin and
lignin, organic nitrogen.
o BIOLOGICAL PARAMETERS — BOD,
coliforms.
Most information is obtained by measur-
ing conductivity (which reflects salts and
free volitile fatty acids), color or absor-
bance at 300 nm (which reflects iron and
organics), and pH (a low value indicates
presence of free volatile fatty acids).
When more parameters are "to be measured,
they should include COD (which reflects con-
centration of organics) and TS (which re-
flects presence of organics and inorganics).
After the above five parameters exceed a
certain value, it is especially warranted
to determine other parameters such as TOC,
free volatile fatty acids, BOD, organic N,
or specific anions and cations.
When an organic characteristic such
as TOC or organic N is measured, the in-
organic equivalent should also be included
(the bicarbonate concentration and the
ammonia concentration, for example). The
ratio organic C/(organic C + inorganic C)
then reflects the degree of biological
stabilization of the sample, as acid fer-
mentation followed by methane fermentation
connects the complex organics to free
volatile fatty acids, which are then con-
verted into CH4 and C02. The latter dis-
solves to a significant degree into the
leachate and is reflected in the increased
bicarbonate concentration. A high ratio
would indicate little organic degradation,
whereas a lower ratio would reflect in-
creasing stabilization. A problem arises
in that the only accurate method to measure
the inorganic carbon is using a dual chan-
nel organic carbon analyzer or the inor-
ganic channel. This is a,piece of analy-
tical equipment not found routinely in
laboratories today.
METHODOLOGY SOURCES
For a complete listing of methods of
analysis the paper by Chian and DeWalle (1)
should be consulted. Generally, the
methods are taken from Standard Methods (4)
and Methods for Chemical Analysis of Water
and Wastes (5).
CONCLUSIONS
Several pollution parameters of samples
taken from a recently leached landfill vary
immediately after being collected unless
strict anaerobic sampling and storage con-
ditions ar.e maintained. Preliminary lab-
oratory studies on physical, chemical, and
biological parameters reveal that color,-
SS, and high salt content associated with
leachates can interfere with colorimetric
methods of chemical analysis. Interfer-
ences can possibly be circumvented by using
a standard addition technique in which re-
covery is determined.
This obtained percent recovery is then
used to readjust the measured value.
Another avenue to remove interferences is
the dilution technique. This is an attempt
to dilute the leachate samples with in-
creasing amounts of water to determine if
the interfering effect can be reduced or
174
-------
overcome. Some researchers maintain this
technique is less accurate than the standard
addition technique.
It is beyond the scope of this paper to
attempt to identify all potential problems
involved in the analysis of leachate. The
analyst must take all precautions identified
in the method references, especially to be
sure that interferences inherent to the
sample and from external sources are recog-
nized and eliminated or neutralized.
RESEARCH NEEDS/ACTIVITIES ONGOING
Based on the results of various other
research efforts, the USEPA recently awarded
a grant to Stanford University (7) to study
the precision and accuracy for several
methods of analysis of pollution parameters.
It is expected that up to 5 pollution para-
meters will be extensively evaluated by
some 25 laboratories. Statistical evalua-
tion of the data generated will determine
the precision of each of the methods, while
comparison of different methods used to de-
termine each parameter will further illus-
trate the accuracy of each test. The
project duration is one year.
In a report entitled "Chemical Quality
and Indicator Parameters for Monitoring
Landfill Leachate in Illinois," Clark and
co-workers(2) sampled 54 landfills in 35
Illinois counties. Thirty-seven parameters
were analyzed in the leachate samples, and
the results clearly showed the diverse
nature of leachate quality. This study
reaffirmed the recommendation of Chi an and
DeWalle that many samples of different
strengths and from different locations
should be investigated to substantiate the
applicable method of analysis.
Further research is recommended to es-
tablish correlations between specific con-
stituents and general constituents such as
conductivity, absorbance at 400 nm, and pH.
These three characteristics are easy to de-
termine and can be valuable for monitoring
and enforcement purposes; however, analysis
for an extended list of pollutants is time
consuming and expensive. Mooij(6) recommends
a short, selected list of indicator para-
meters, chosen to represent the landfill,
the surrounding environment, and the con-
ditions under which leachate will travel.
He further states that upon appearance of
one or more of the selected parameters, more
detailed analyses should be conducted.
Chloride, hardness, iron, sulphate, and
specific conductance have been used as
indicator parameters. The recommendations
of Mooij call for more detailed-analyses
parallel those of Chian and DeWalle.
Research is needed to establish the
exact nature of interfering substances
and potential method development to cir-
cumvent interferences. Using this ap-
proach Streng3 found that interferences
play a major role in chloride analysis in-
volving any established methodology.
Therefore, he set out to develop an in-
direct method for the determination of
chloride, employing atomic absorption
spectroscopy (AA). This indirect method
requires no sample pretreatment and
greatly reduces the time and effort re-
quired in analysis with no apparent loss
of accuracy or precision. At this time
the AA approach is the first reported
effort of its kind and is still in the
developmental stages. However, publication
of the method is expected and interested
researchers should contact Streng regarding
this approach to chloride analysis in
leachate.
In general, future research efforts
should be directed to either developing
methods of analysis that are not suscepti-
ble to the interferences found in leach-
ates, or to finding ways of removing the
interferences while using approve analyti-
cal methods. These removal techniques
could include ion exchange, activated
carbon treatment, coagulation effects, or
lime dosing.
REFERENCES
1. Chian, E.S.K. and F.B. DeWalle, "Com-
pilation of Methodology Used for
Measuring Pollution Parameters of
Sanitary Landfill Leachate-." EPA-600/
3-75-011, October 1975, Ecological
Research Series.
2. Clark, T.P. and R. Piskin, "Chemical
Quality and Indicator Parameters for
Monitoring Landfill Leachate in
Illinois." Environmental Geology,
V. 1, No. 6, pp 329-339. 1977.
3. Streng, D. Progress Report U.S. EPA
Contract 68-03-2120, "Evaluation of
Landfill Gas and Leachate Production."
Oct. 1976,
175
-------
4. APHA, "Standard Methods for the Examin-
ation of Water and Wastewater," 13th Ed.
American Public Health Association,
Washington, D.C. (1971).
5. The Environmental Protection Agency,
"Methods for Chemical Analysis of Water
and Wastes," U.S. EPA, Office Of Tech-
nology Transfer, Washington, D.C.
(1974).
6. Mooij, H., "Procedures for the Analysis
of Landfill Leachate," Appended Seminar
Proceedings Report by R.D. Cameron and
E.C. McDonald, Dept. of Civil Engineer-
ing, University of British Columbia,
Vancouver, B.C., Canada.
7. Research Grant R804883-01, "Analytical
Methods Evaluation for Applicability in
Leachate Analysis, EPA Project Officer,
Donald Sanning.
176
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LEACHATE TREATMENT BY BIOLOGICAL AND PHYSICAL-CHEMICAL METHODS
OF LABORATORY EXPERIMENTS
Foppe B. DeWalle
Stanford University
Stanford, California
and
Edward S. K. Chian
University of Illinois
Urbana, Illinois
-- SUMMARY
INTRODUCTION
In recent years, it has become well
known that land disposal of solid waste in
a humid climate will frequently produce
leachate as a result of rainwater infil-
trating the solid waste. This leachate
often contains a high concentration of
organic matter and inorganic ions. A
number of incidents have been reported
where leachate has contaminated the sur-
rounding soil and polluted an underlaying
groundwater aquifer or nearby surface
water. One way to avoid or to correct
such situations is to collect and treat
the leachate.
The treatability of leachate has been
reported by Boyle and Ham (1) using both
aerobic and anaerobic biological processes.
Aerobic and anaerobic stabilization of
sanitary landfill leachate was also studied
by Cook and Foree (7), and Rogers (19).
A COD reduction between 58 and 99% was
attainable by a single-step biological
process. Boyle and Ham (1) and Foree and
Reid (10) have also reported a two-step
biological treatment process employing an
anaerobic digester or filter followed by
an aerated lagoon. Further reduction in
COD, between 22 to 40 percent of the
effluent COD of the first unit, has been
accomplished by these investigators (1,10).
The use of chemical precipitation and
oxidation methods for leachate treatment
has been reported by Boyle and Ham (1),
Karr (15), Cook and Foree (7), Ho, Boyle
and Ham (13), Thornton and Blanc (22),
Rogers (19), Simensen and Odegaard (21)
and Roy F. Weston, Inc. (20). Other
physical-chemical processes for leachate
treatment, such as activated carbon and
ion-exchange adsorption and reverse osmosis,
have been studied by Cook and Foree (7),
Ho, Boyle and Ham (13), Karr (15),
Pohland and Kang (17), Van Fleet et al_. (23)
and Roy Weston, Inc. (20). The results of
these physical-chemical methods of leachate
treatment showed a wide variation of
removal efficiencies which may well be due
to the variable nature of the landfill
leachates employed in these studies.
The purpose of this study was to
summarize the results of all of the previous
studies on leachate treatment and to devise
a scheme of general applicability to treat
leachate and to test this scheme syste-
matically. The proposed scheme for
leachate treatment under this study is
given in Figure 1.
MATERIALS AND METHODS
The leachate employed in this study
was collected from a lysimeter installed
at the University of Illinois. This
leachate contained a COD, TOC, and BOD of
49,300 mg/1, 17,060.mg/l and 24,700 mg/1,
respectively, and had a pH of 5.63. The
iron content of this leachate was as high
as 2,200 mg/1.
The biological processes evaluated in
this study included activated sludge,
aerated lagoon and anaerobic filter. The
-------
1 LEACHATE
fAERATEO LAGOON (AL)
BIOLOGICAL I ANAEROBIC FILTER (AT)
TREATMENT } ACTIVATED SLUDGE (ASI
[ANAEROBIC FILTER-AL
BIOLOGICAL AND
PHVSCOCHEMKAL
TREATMENT
fCHEMICA).PRECIPITATION (CP)
I REVERSE OSMOSIS (RO)
1 ACTIVATED CARBON (AC)-RO
[no-AC
Figure 1. The Proposed Experimental Flow
Diagram for Studies of the
Promising Treatment Processes
activated sludge experiments were conducted
with a test and a control unit operated in
parallel and maintained at the same F/M
ratio (g.BOD remoyed/g.MLVSS.day). The
test unit, a 57-liter laboratory scale
plug-flow activated sludge unit, received
municipal sewage with a leachate addition
of 0.5, 1, 2, 3 and 4 percent by volume
while maintaining an F/M ratio of 0.3
dayl. Two other F/M ratios, i.e., 0.6
and 1.0 day'T were also studied while
maintaining a leachate addition of 2
percent by volume. Comparisons of the
sludge settling characteristics and the
effluent BOD and COD were then made
between the control unit and the test unit.
The aerated lagoon or the extended
aeration process employed six completely
mixed vessels fed with undiluted leachate
with no sludge recycle. The tested
hydraulic detention times, which were
equal to the sludge ages, were 85.7, 60,
30, 14 and 7 days. These units were
operated for periods from 70 to 150 days.
The phosphorus requirements of the aerobic
biomass were evaluated extensively, while
phosphorus and nitrogen were added to the
leachate in an amount of twice that needed
for nutritional requirements.
A completely-mixed 56-liter anaerobic
filter packed with "Surpac" slabs (Dow
Chemical, Midland, MI) was used. The
porosity of the filter was 94 percent with
a specific surface area of 2.06 cm2/cm3.
No nutrient addition was needed. The
hydraulic detention studies were 7.5,17.5,
42 and 74 days. Recycling of the effluent
from the anaerobic filter was made to
buffer the pH of the leachate fed to the
unit and to keep the liquid inside the
filter well mixed.
Physical-chemical methods were
employed to treat both the raw leachate
and the effluents from various biological
processes. These processes were found to
be not effective in treating the highly
polluted leachate used in this study and
further research was therefore cencentrated
on their applicability in the treatment of
the effluent. Chemical precipitation
experiments were conducted on effluents
from the aerated lagoon and anaerobic
filter using the standard jar test
apparatus. Activated carbon studies were
conducted with Filtrasorb 400 (Calgon,
Pittsburgh, PA) with both batch dosages
and columns. Ion-exchange adsorption
studies were conducted with Duolite A-7
(Diamond Shamrock, Redwood City, CA),
Amberlite IRA-938 and XE-297 HP (Rhom and
Haas, Philadelphia, PA) in columns.
Reverse osmosis studies on raw leachate
and the effluent from the aerated lagoon
were carried out with cellulose acetate
and NS-100 membranes housed in a 3"-dia.
stainless steel high-pressure test cell
operated at 600 and 1500 psig under
nitrogen atmosphere. A DuPont B-9
permeator (Wilmington, DE) operated at
400 psig was used to treat effluent from
the anaerobic filter. Ozonation of
biological effluent was carried out in
a well-baffled one-liter glass reactor
fed with 03/02 mixture.
RESULTS AND DISCUSSION
Activated Sludge
The effect of increased leachate
additions on influent BOD:P.ratio and the
effluent COD and BOD concentrations is
summarized in Figure 2. The F/M ratio of
these runs was maintained at 0.3 day~l.
178
-------
a
o
03
O
en
100 ^
o»
80 E
o
60 S
40 S
30 t
ui
1234
Leochote /Sewage, % By Volume
Figure 2. The Effect of Increased
Leachate Additions on the
Influent BOD/P Ratio and the
Effluent COD and BOD Concen-
trations of the Test Unit
A comparison of the results of the test
(Figure 2) and the control units (Figure 3)
shows that increasing leachate additions
does not greatly affect effluent BOD values
although the COD values in the effluent
are consistently higher from the test unit
than that from the control. However, at
4% leachate addition, the BOD values in
the effluent of the test unit increased
with increasing time of operation. The
test was discontinued at this leachate
addition level because of deteriorating
effluent quality. Boyle and Ham (1)
found that leachate with COD of 10,000
mg/1 could be added to domestic sewage in
an extended aeration activated sludge
unit at a level of at least 5% by volume
without seriously impairing the effluent
quality; however, the leachate in their
study was 5 times weaker. The failure of
the test unit at 4% by volume of leachate
addition was attributable to a phosphorus
deficiency as shown in Figure 2, where the
BOD:P ratios in the influent varied from
130 to 255.
The effect of increasing loadings on
the effluent characteristics was also
studied at a constant leachate addition
280
240
200
•S.
C7>
e_ 160
o
^ 120
89
i 80
/>
4O
0
a
o
cc
Leochate
•77^03 day'1 -= = 3%
- M Sewage
-lest Unit
Control Unit
I
I
I
1
13 14 15 16 17 18 19 20
November, 1973
Figure 3. The Effect of 3% Leachate
Addition on Effluent Quality
of the Activated-Sludge Process
of 2%. The results showed that the BOD of
the test unit was consistently higher than
that of the control unit at an F/M ratio
of 0.6 and 1.0 day1. At the highest
loading of 1.0 dayl studied, the effluent
BOD of the test unit (Figure 4) increased
noticeably with time, indicating that the
activated sludge unit is preferably oper-
ated at low F/M ratios when receiving
leachate additions.
The sludge settling characteristics
show that the addition of 0.5% leachate
resulted in a decreased settling rate of
the sludge interface; increasing the
leachate addition (up to 3%) at the same
loading (i.e., 0.3 day~1), however, did
not further deteriorate the settling
characteristics (Figure 5). The impair-
ment of the sludge settling was even more
noticeable at the higher sludge loading,
e.g., 0.6 day"'. The presence of high
concentration of iron in leachate with
resulting low soluble phosphate concentra-
tion may have contributed to the impaired
sludge settling upon leachate addition.
Therefore, the addition of even a small
amount of leachate to the activated sludge
process would tend to impair the sludge
179
-------
240
200
ISO
i20
80
40
Figure 4.
20 21 22 23 24 25 26
February, 1974
Effluent Quality During 2%
Leachate Addition at the 1.0
F/M Ratio
settling in the secondary clarifier of an
existing plant and additional capacity is
therefore required. However, the advantage
of leachate additions is the resulting low
levels of phosphate in the effluent of the
test unit, i.e., on the order of a fraction
of 1 mg/1.
Aerated Lagoon
The effect of detention time and thus
the organic loadings on the effluent TOC
concentrations during a 150-day period of
operation is given in Figure 6. The
percentage of TOC reduction varies from
98.2 to 99.2% as the organic loading
decreased from 1.94 to 0.67 kg TOC/M3 day
(5.61 to 1.94 kg COD/M3 day) which
corresponds to an increase of detention
time from 30 to 85.7 days. Cook and
Foree (7) reported COD stabilization
efficiency of greater than 97%. Karr (15)
and Pohland and Kang (17) obtained
variable effluent qualities while operating
at lower detention times ranging from 2
(00
80
60
40
20
5 10
I 8
I 6
Leachotc
Sewojt
03
0 I
0 3
0 3
06
07.
0.5%
I 0%
3 0°!,
20%
0.1 0.2 04 06 Ofl IO 2.0
Sludge Concentration %
4O 60 80 IO
?0 JO *0 !O 60 TO 83 3D ICO 110 120 150 140 ISO
Figure 5. The Effect of Leachate Addition
on the Sludge Settling
Characteristics
Figure 6. Total Organic Carbon in
Effluent of Aerated Lagoons
1, 2 and 3 Treating Leachate
180
-------
to 15 hours and 2.3 to 8 hours, respec-
tively, and organic loadings varying from
4.5 to 54.2 kg COD/M3 day and 1.5 to 5.3
kg COD/M3 day. The mixed liquor volatile
suspended solids (MLVSS) decreased from
12,000 to 8,000 mg/1 as the detention
time increased from 30 to 85.7 days. The
high suspended solid content in the lagoon
requires intensive mixing and aeration of
these units. The kinetics constants
determined from these runs are 0.42 mgVSS/
mgCOD. 0.025 day'1 and 4.9 x 10'4 (mg/1
VSS)-' (day)"', respectively, for the
yield, the microorganism-decay coefficient
and the overall first-order substrate
removal rate constant per unit weight of
microorganism which agreed well with that
reported by Cook and Foree (7).
An extensive evaluation of phosphate
requirements showed that the COD:P ratio
in the influent of the 30-day unit should
be at least 300:1. For units with a
retention time of 85.7 and 60 days, they
were even able to be operated with a
COD:P ratio of 1540:1 in the feed
solution. Cessation of nutrient addition
at a COD:P ratio of 165:1 to the units
operated at relatively low detention times,
e.g. 7.5 and 15 days, caused an immediate
increase in effluent organic matter, a
decrease in biological MLVSS and a
deterioration of sludge settling rates.
All units operated at various deten-
tion time showed high removals of heavy
metals, especially for iron (99.9%), zinc
(99.9%), calcium (99-.3%) and magnesium
(75.9%). Lower removals were observed
for sodium (24.1%) and potassium (17.0%).
The high removals of heavy metals appear
to be related to chemical precipitation
and flocculation in the aerated lagoon
whereas the low removals for sodium and
potassium appear to be biologically
mediated.
Since an appreciable amount of sludge
was produced from the aerated lagoon,
considerations were also given to sludge
disposal. The dewatering characteristics
of the sludge from the 30-day unit were
greatly improved by the addition of
cationic polymers (Primafloc C7, Nalco
73C32) and inorganic coagulants. An
approximate 20 times decreases in the
specific resistance of the sludge was
obtained at polymer dosages varying
between 0.15% to 1.5% and inorganic
dosages of 2,9% to 25.5% on the basis of
dry sludge weight. These decreases in
the specific .resistance corresponded to a
6-time increase in vacuum filter yields.
Anaerobic Filter
Studies on the effectiveness of the
anaerobic filter in treating leachate were
conducted for a period totaling 518 days.
During the initial phase'of the situdy,
which lasted 218 days,, the different
start-up procedures, pH stabilities and
shock loadings of the unit,were tested.
In phase II of the study, which lasted
250 days, the various operational
difficulties of the completely mixed unit
were evaluated. In the last phase of the
anaerobic filter experiment, which lasted
50 days, the effect of organic loadings
on the effluent characteristics was
studied.
The recirculation ratio of the
anaerobic filter effluent was studied
after one volume turn over, i.e.,,42 days
of operation. Based on the add
(sulfuric acid) titration of the effluent,
five parts of effluent were required to
increase the pH of the influent to 7.0.
Therefore a minimum ratio of 1:6, i.e.,
one part of leachate sample to five parts
of effluent, was required. In order to
operate the unit safely and well-mixed the
ratio of 1:20 was maintained, resulting in
a complete turnover of the liquid volume
in the unit every 1.8 days. Since the
time required for mixing was short as
compared to the hydraulic detention time,
i.e., 1.8 days versus 42 days, the unit
can be considered completely mixed. The
use of a completely-mixed anaerobic filter
will allow utilization of the entire
length of the filter column for substrate
removal; in plug flow units, however,
only the lower one meter (3.3 ft.) is
generally effective in substrate removal
according to Young and McCarthy (24,25)
and Jennett and Dennis (14). When the
unit was loaded with 6, 10 and 14 times
the initial rate of leachate addition,
the initial decrease in pH and upsurge in
gas production leveled off after about
six days of operation, indicating good
stability of the unit under conditions of
various shock loadings.
181
-------
During the initial stage of the phase
II study, 97% of the COD was removed at a
loading of 0;62 kg COD/M3 day. Up to 89%
of COD was removed in the form of methane
gas leaving the" system, whereas the
remainder of COD was present in the form
of inorganic carbon in the solution. Only
a small amount of COD was removed as bio-
mass accumulated in the anaerobic filter.
The low!yielcTof biomass, i.e., approxi-
mately 6.012 g biomass produced per g of
COD removed, allowed the filter to be
operated without nutrient addition. Due
to the low yield of biomass, the COD:P
and COD:N ratios in the feed could be
maintained at 4360:1 and 39:1, respectively,
without impairment of the filter operation.
Any P requirement was sufficiently met by
the addition of the anaerobic digester
sludge added to the unit initially for
seeding.
Heavy metal toxicity was observed
which resulted in the COD removal decreased
to as low as 64% with the unit during
phase II of the study. AnaJysis of the
effluent showed a gradual increase in
soluble heavy metals from an undetectable
amount to as,high as 2.8, 0.9, and 0.2
mg/1"respectively for Fe, Cu and Zn.
High Cu"content may have contributed to
the malfunction of the anaerobic filter.
This was, however, eliminated after addi-
tion of 75 mg/1 NagS to the column
content. The sulfide addition caused a
decrease in oxidation reduction potential
(ORP) values while reducing the heavy
metal concentrations.
In view of the lower installation
and operation costs of the anaerobic filter
as compared with those of the aerated
lagoon (16), it is obvious that the
anaerobic filter is a preferred biological
process of treating high strength"leachate.
In addition, the absence of any nutrient
additions, the extremely low yield of
biological solids and the production of
useful energy, i.e., methane gas, strongly
supports the use of the anaerobic filter
for leachate treatment. As a result of
this study, a pilot-scale 25,000 gal.
anaerobic filter was constructed by the
City of Enfield, CT, funded by OSWAMP
(US-EPA), and is currently being evaluated
for treating leachate generating from the
landfill site located in the Township.
Physical-Chemical Treatment
Since the raw leachate generated
from a recently installed landfill con-
sists mainly of low molecular weight
volatile fatty acids (6), it is more
amenable to the various biological treat-
ment processes than to physical-chemical
processes. Neither activated carbon nor
ion-exchange resins will adsorb these low
molecular weight volatile fatty acid
effectively (11). Removal of volatile
fatty acids is also quite low with the
reverse osmosis process (8) without pH
adjustment. Although adjustment of pH
to higher values, e.g., 9, would increase
the membrane rejection of these organic
compounds (9) appreciably, the high
buffering capacity of the raw leachate
renders this economically unattractive.
Ozone oxidation of these volatile fatty
acids was also found to be slow under the
prevalent acidic pH of the leachate (4,12).
The use of an excessive amount of chemical
coagulants, e.g., up to 2,700 mg/1, to
chemically precipitate the raw leachate
resulted in only less than 30% removal of
COD (7,13,15,21,22,23). However, after
treating the leachate with biological
processes, the residual orga'nics in the
treated effluent consist mainly of high
molecular weight carbohydrate, huinic and
fulvic acid complexes (2,5) and are
therefore more amenable to removal by
physical-chemcial processes. These
effluent organics are characterized by
lower BOD:COD and COD:TOC ratios as com-
pared with the raw leachate due to removal
of organics with a high BOD/COD and
COD/TOC ratio in the biological process.
The above conclusion has been torne out
by several studies on the treatability of
leachate. While Boyle and Ham (1) noted
a 932'COD removal in anaerobic digesters,
Ho, Boyle and Ham (13), using a similar
leachate, obtained only a 34% COD removal
rate using activated carbon at a maximum
dosage of 20,000 mg/1; or a 59% removal
of COD using a granular activated carbon
(Filtrasorb 400) column having a detention
time greater than 20 minutes. The leachate
studied, having a high BOD/COD and COD/TOC
ratio, was generated from a relatively
recent fill as indicated by its high free
volatile fatty acid content, i.e., 65% of
the COD organics. After biological treat-
182
-------
ment of a similar leachate, Pohland and
Rang (17) obtained a COD removal in the
effluent of as high as 91% using activated
carbon, indicating that biological treat-
ment followed by carbon adsorption will
result in high organic removal. Cook and
Foree (7) also obtained a high percentage
of COD removal, i.e., 70%, while treating
aerated lagoon effluent with activated
carbon. Roy F. Weston, Inc. (20) on the
other hand, observed an 89% COD removal
with leachate collected from a stabilized
landfill site indicating that when the
landfill has been subject to extensive
biological stabilization, it is not
necessary to treat the leachate by biolog-
ical treatment processes prior to the
activated carbon treatment. Since stabil-
ized leachate consists mostly of high
molecular weight humic substances as
characterized by a low BOD/COD and COD/TOC
ratio, it is to be expected that activated
carbon will remove these compounds
effectively. Results of the present study
show that 70% of COD in effluent of the
aerated lagoon and aerated effluent of
anaerobic filter can be removed by the
carbon columns. Up to 50% of the COD in
the effluent of anaerobic filter were
removed indicating that leachate was
stabilized to a lesser extent with the
anaerobic filter (42-day hydraulic deten-
tion time) as compared witj) the aerated
lagoon (30-day hydraulic detention time).
Only 50-58% removal of orqanics in aerated
lagoon effluepts was accomplished by ion-
exchange resin (3,17) indicating its
inferiority to activated carbon processes.
It was found that reverse osmosis
like activated carbon also removes
the high molecular weight carbohydrate
humic complexes more effectively than the
free volatile fatty acids and is thus more
suitable for treating biologically
stabilized leachate effluent and leachate
obtained from stabilized landfills.
Whereas the present study noted only a
56% removal of organics with raw leachate
generated in a recent fill, as much as 95%
COD removal was obtained in anaerobic
filter effluent using the conventional
cellulose acetate membrane (at a product
water recovery of 50%). In both cases
better removal of organics with reverse
osmosis can be obtained using membranes
having better capabilities of rejecting
organics, such as the newly fabricated
DuPont's B-9 permeator. Up to 98% removal
of organics was obtained with the aromatic
polyamide membrane used in the B-9 perme-
ator at a greater percentage of product
water recovery, i.e., 75%. Using a
leachate collected from a stabilized land-
fill site, Roy F. Weston, Inc. (20) was
able to accomplish 80% removal of organics
at a product water recovery rate of 80%.
Chemical oxidation of raw leachate as
well as effluent from biological units
employing calcium hypochlorite and ozone
showed that relatively little COD could
be removed even with 3 to 4 hours of oxida-
tion (3,13,15). For leachate collected from
a nearby stabilized landfill site, Roy F.
Weston, Inc. (20) observed no removal of
organics with calcium hypochlorite whereas
22% removal of COD was obtained with ozon-
ation after 4 hours. Up to 48% and 37%
removal of COD was observed respectively in
the present study with ozonation of aerated
lagoon and anaerobic effluent. Due to the
low COD removal as well as the high costs
of these chemical oxidants, chemical oxida-
tion does not appear to be feasible for
leachate treatment.
Of all the physical-chemical methods
evaluated by the previous investigations and
in the present study, reverse osmosis membrane
treatment was found to be more effective
in removal of organics, especially when
applied to biologically treated and highly
stabilized leachates. Special precautions,
however, may have to be used to prevent mem-
brane fouling. The membrane process is
followed in effectiveness by activated
carbon treatment of biologically treated
and stabilized leachate.
Since treatability of leachate is
closely related to the chemical composi-
tion of leachate, the organic matter
removal with each process can be related to
CQD/TOC and BOD/COD ratios-. Figures 7 & 8
summarize treatment data from this study
as well as those reported in the litera-
ture. It should be noted that the envel-
opes in Figure 7 and 8 for the percentage
of COD removal versus BOD/COD and COD/TOC
ratios only serve to indicate the general
trends of COD removal that would occur
with different BOD/COD and COD/TOC ratios
in raw leachate or biologically stabilized
leachate and do not have any statistical
significance. The individual envelope
was generated using extreme values for its
boundary. They are, therefore, useful to
183
-------
80|- Chemical
Precipitation
o
o
o
irobic
Biological
Treatment
Activated
• Carbon
o Batch \\
00 - donation and
Chlorlnation
60
Anaerobic
Biological
Triatm*nt
-I 1 I-
Reverie
0*mosii
J I L
0.2 0.4 0.6 0.8 0 02 0.4 0.6 0.8 1.0
BOO / COD Ratio
Figure 7. Percentage of COD Removal by
Various Treatment Processes
Versus BOD/COD Ratio
o
o
o
Activated
Carbon
o Botch
Column,
COO / TOC Ratio
Figure 8. Percentage of COD*Removal by
Various treatment Processes
Versus COD/TOC Ratio
select treatment processes that are
optimum for treating a specific leachate
with known ratios of BOD/COD or COD/TOC.
Follow-up laboratory experiments, however,
are recommended to ascertain the selection
of each of the specific treatment processes.
CONCLUSIONS
High strength leachate (e.g., COD >
5,000 mg/1) generated from recently
installed landfills is more amenable to
biological treatment processes. This
leachate is characterized by high ratios
of both BOD/COD (> 0.4) and COD/TOC
(> 2.8). Low strength leachate (e.g.,
COD < 1,000 mg/1) generated from a stabil-
ized landfill or present in effluent of
biological units treating leachate is more
amenable to physical-chemical treatment
processes. This leachate is generally
characterized by a low ratio of either
BOD/COD (< 0.2) and/or COD/TOC (< 2.5).
Of all biological processes evaluated,
the anaerobic filter was found to be the
most economical process due to its lower
capital and operating costs. Reverse
osmosis and activated carbon were found
applicable to remove residual organic
contaminants in effluent of biological
leachate treatment units.
REFERENCES
1. Boyle, W. C. and Ham, R. K.,
"Treatability of Leachate from
Sanitary Landfill," Journal Water
Pollution Control Federation, 46,
No. 5, May 1974, pp. 860-872.
2. Chian, E. S. K., "Stability of Organic
Matter in Landfill Leachates," Water
Research, JJ_, No. 2 (1977)
pp. 225-232.
3. Chian, E. S. K. and DeWalle, F. B.,
"Sanitary Landfill Leachates and
Their Treatment," ASCE Envir. Engr.
Div.. 102. No. EE2 (1976)
pp. 411-431.
184
-------
4. Chian, E. S. K. and Kuo* P. P. K.5 13.
"Fundamental Study on the Post-
Treatment of RO Permeates from Army
Wastewaters," Second Annual Report,
Contract No. DAMD, 17-75-C-5006, U.S.
Army Medical Research and Development
Command, Fort Detrick, MD, 1976. 14.
5. Chian, E. S. K. and DeWalle, F. B.,
"Sequential Substrate Removal in
Activated Sludge Systems Fed with
Naturally Occurring Wastewater," Prog.
in Mater Tech.. 7_, No. 2 (1975) 15.
pp. 235-241.
6. Chian, E. S. K. and DeWalle, F. B.,
"The Composition of Organic Matter in
Leachate," Environmental Sci. and
Tech.. 11. No. 2 (1977) pp. 158-163. 16.
7. Cook, E. N. and Foree, E. G.,
"Aerobic Biostabilization of Sanitary
Landfill Leachate," J. Water Poll.
Cont. Fed.. 46, No. 2 (1974)
pp. 380-392.
17.
8. Fang, H. H. P. and Chian, E. S. K.,
"Reverse Osmosis Separation of Polar
Organic Compounds in Aqueous
Solution," Env. Sci. and Tech., 10,
No. 4 (1976) pp. 364-369.
9. Fang, H. H. P. and Chian, E. S. K.,
"Removal of Alcohols, Amines and 18.
Aliphatic Acids in Aqueous Solution
by NS-100 Membrane," J. Appl.
Polymer Sci.. 20, No. 2 (1976)
pp. 303-315.
10. Foree, E. G. and Reid, V. M.,
"Anaerobic Biological Stabilization 19.
of Sanitary Landfill Leachate,"
Technical Report TR 65-73-CE17,
Department of Civil Enginering,
University of Kentucky, Lexington,
Ky. (1973).
11. Guisti, D. M., Conway, R. A., and
Lawson, C. T., "Activated Carbon
Adsorption of Petrochemicals," 20.
J. Water Poll. Cont. Fed., 46, No. 5
(1974) pp. 947-965
12. Hewes, C. G., Prengle, H. W., Mauk, 21.
C. E. and Sparkman, 0. D., "Oxidation
of Refractory Organic Materials by
Ozone and Ultraviolet Light," Final
Rpt. 7184, U.S. Army Mobility Equip-
ment Res. & Dev. Center (1975).
Ho, S., Boyle, W. C., and Ham, R. K.,
"Chemical Treatment of Leachates from
Sanitary Landfills," J. Hater Poll.
Control Fed.. 46_, No. 7 (1974)
pp. 1776-1791.
Oennett, 0. A. and Denniss, N. D.,
"Anaerobic Filter Treatment of Phar-
maceutical Waste," J. Mater Poll.
Control Fed., 47_, No. 1 (1975)
pp. 106-121.
Karr, P. R. Ill, "Treatment of
Leachate from Sanitary Landfills,"
Special Research Problem, School of
Civil Engineering, Georgia Institute
of Technology, Atlanta, GA., (1972).
Pailthrop, R. E., et al_., "Anaerobic
Secondary Treatment of Potato Process
Waste Water," Paper presented at the
44th Water Pollution Control Federa-
ion Annual Conference, San Francisco,
CA (1971).
Pohland, F. G. and Kang, S. J.,
"Sanitary Landfill Stabilization with
Leachate Recycle and Residual Treat-
ment," American Institute of Chemical
Engineers Symposium Series No. 145,
Water-1974, Vol. 71 (1975) pp. SOS-
SIS.
Pohland, F. G. and Maye, P. E.,
"Landfill Stabilization with Leachate
Recycle," presented at the March 5-6
(1970), 3rd Annual Environmental
Engineering Science Conference, held
at Louisville, KY.
Rogers, W. P., "Treatment of Leachate
from a Sanitary Landfill by Lime
Precipitation Foil owed by an Anaerobic
Filter," Thesis presented to Clarkson
College of Technology at Potsdam,
N.Y., (1973), in partial fulfillment
of the requirements for the degree of
Master of Science.
Roy F. Weston, Inc., Interim Report
No. 463-10 by J. Weaver, West Chester
PA (1973).
Simensen, T. and Odegaard, H., "Pilot
Studies for the Chemical Coagulation
of Leachate," Norwegian Institute of
Water Pollution Research, Blindern,
Oslo, Norway (1971).
185
-------
22. Thornton, R. J. and Blanc, F. C.,
"Leachate Treatment by Coagulation
and Precipitation," J; of the Envir.
Engr. Div., ASCE, 99_, No. E4, Proc.
Paper 9946, TJ973) pp. 535-539.
23. Van Fleet, S. R. et al_., "Discussion,
Aerobic BiostabilizatTon of Sanitary
Landfill Leachate," J. Water Poll.
Cont. Fed.. 46 (1974) pp. 2611-2612.
24. Young, J. C. and McCarty, P. L.,
"The Anaerobic Filter for Waste
Treatment," Dept. of Civil Engr.,
Stanford University, Technical Rpt.
87, 235 (1968).
25. Young, J. C. and McCarty, P. L.,
"The Anaerobic Filter for Waste
Treatment," J. Water Poll. Control
Fed., 41, R160 (1969).
186
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LEACHATE TREATMENT BY SOIL METHODS
Grahame J. Farquhar
Associate Professor of Civil Engineering
University of Waterloo
Waterloo, Ontario, Canada
Abstract
This paper examines the mechanisms of contaminant attenuation active in
experiments on soil - landfill leachate contact. Ten soils were used in both
column and dispersed soil reactor (DSR) configurations. Anoxic conditions were
maintained. Leachate was allowed to pass through the soils and contaminant
reduction during passage was measured.
Sorption processes including ion exchange were the most active of the
mechanisms considered. They influenced the removal of most cations present as well
as organic matter (COD). Removal isotherms for NH,, Fe , Zn , K and COD showed
positive correlation with cation exchange capacity of the soil. The release of
Ca^+ and Mg during contact identified the existance of ion exchange.
Dispersion and dilution actively influenced contaminant concentration.
Asymmetric breakthrough curves suggested incomplete contaminant mixing in non-
migrating water.
2+ 2+ 2+
The concentrations of Zn , Fe and Mn in the leachate exceeded predicted
solubilities as pH increased to neutrality during soil contact. The potential for
removal by precipitation appeared to exist.
The destruction of organic matter through anaerobic microbial action was
limited by incomplete culture development.
Filtration functioned to remove small amounts of suspended solids in the
leachate and any precipitates formed. Gaseous exchange was assumed to exist as the
partial pressure of carbon dioxide reduced to atmospheric conditions.
The stability of these mechanisms was tested by the passage of2water through
the soils after leachate contact. Little or no release was shown for Fe , Mn2+ and
Zn , slight to moderate for NHJ and K+ and substantial for COD and Na+.
The use of DSR data in modelling contaminant removal during continuous
flow was demonstrated.
187
-------
INTRODUCTION
EXPERIMENTATION*
Since the early 1970's, there has
been a dramatic increase in research
dealing with groundwater contamination
from solid and liquid waste disposal in
soil. On-aiteinvestigations have
identified the complete spectrum of
environmental impacts ranging from
disposal with little or no deleterious
effect to the production of highly
toxic conditions within the groundwater
system. In the majority of cases.
involving the landfilling of municipal
solid wastes, the impact upon the
groundwater system has been tolerable.
This has been generally attributed to
the attenuation of contaminant con-
centrations during leachate movement
through the soil.
Of the mechanisms associated with
contaminant attenuation, the most
frequently cited are (1, 2, 3);
1, dispersion and dilution
2. sorption including ion
exchange
3. precipitation
4. biological transformation
5. gaseous exchange
6. filtration.
The properties of the soil
environment that influence the extent
to which these mechanisms are operative
appear to include (1, 2, 3):
1. soil grain size
2. organic content
3. cation exchange capacity
4. pH
5. Eh
6. hydrous oxides
7. free lime content
The relative importance of one
property over another is not well
documented. It is likely to vary from
one situation to the next.
A programme of research into
landfill contaminant attenuation in
soil has been underway at the University
of Waterloo for several years. Its
purpose has been, in part, to identify
the types of mechanisms involved and the
extent of this involvement. The paper
presented here describes some of the
results from this research.
Bench-scale experiments were
performed in the laboratory for the study
of soil-contaminant interactions. Ten
soils were collected at depths from 1m to
8m at several landfill sites in Southern
Ontario. The ranges of properties
exhibited by these soils are summarized
in Figure 1. A positive correlation
existed between cation exchange capacity
(CEC) and soil clay content as estimated
by the % dry weight of soil less than
0.002mm particle size. The influence of
increased CEC 'with increased organic
matter in the soil is also shown. Soil
pH values fell between 7.1 and 7.4
inclusive. The clay minerals illite and
chlorite were present in all soils;
quartzite in all but soils 5,6 and 10;
kaolinite in Soils 1, 2, 3, 4 and 6;
montmoriHonite and vermiculite in soils
2, 3 and 4. The dominant resident i^n
on all soils was Ca2 followed by Na ,
Mg2"*" and K+ in that order.
The leachate used for contact-with
soil was generated in a lysimeter charged
with residential solid waste (4). Typical
concentrations for the period of study
are shown in Table 1.
Leachate-soil contact was achieved
in packed columns (7.3cm ID by 40cm
in length) and dispersed soil reactors
(DSR; 5.2cm ID by 25cm in length).
Leachate was added to the top of the
column and allowed to percolate down
through the soil. Effluent samples were
collected and analysed for their chemical
composition. For the DSR's, soil and
leachate were added, shaken, settled and
separated with the residual liquid
analysed as above. The liquid was then
passed on to the next in the series of
10 reactors and the process repeated.
This was done to preserve the influence
of one contaminant on another with respect
to interactions with soil. All activities
were performed under N~ gas to maintain
anoxic conditions.
Estimates of contaminant attenuation
were made and analysed in terms of operative
mechanisms. A discussion of these
mechanisms is presented below.
*The experimental methodology employed in
this research has been presented in detail
elsewhere (3).
188
-------
25 r
^
t-
o
Is20
o w
LU ce
§Q 15
< E
I §>
C5 ^^
B° 10
z^,
o S1
SE 5
Vi;il32-3)
O SOIL NUMBER ENCIRCLED
— ( ) NUMBERS IN BRACKETS SHOW
ORGANIC CONTENT OF SOILS
IN
mg02/gm DRY SOIL. ONLY POINTS
_ 0(2M) GREATER THAN 1-0 ARE SHOWN
©tl-l) ^
©(11-6)
®
\2/
® 1 1 1 • 1 1 1 1 1
10 15 20 25 30 35 40 45
GRAIN SIZE : % DRY wt< 0-002 mm
FIGUBE 1. COMPARISON OF SOIL PROPERTIES
PARAMETER
CONCENTRATION
(mg/1)
TOTAL DISSOLVED SOLIDS 16,024
VOLATILE DISSOLVED
COD
BOD 3
NH4*
ORGANIC - N
PH
TANNINS a LIGNINS
CJ~
S04
NO 3 (as N)
TOTAL DISSOLVED
1 METALLIC IONS
FORM
SOLIDS 9,586
31,490
18,470
915
108
5-65
200
819
790
0-25
P 23
PARAMETER
Co2*
Mg2*
No*
K +
2+ '
Fe
2 +
Mn
Zn2*
Cu2*
Pt,2*
Ni2*
Cr (EH
WERE ASSUMED TO EXIST
CONCENTRATON
( mg/f)
630
118
511
559
71
27
21
0-26
1-3
0-61
0'07
IN THE REDUCED
TABLE 1. TYPICAL LEACHATE COMPOSITION
189
-------
Dispersion, and Dilution
Chemical concentrations in ground-
water are reduced by combinations of
dispersion and dilution. Dispersion is
generallyexplained in terms of the
"bundles of pore channels" concept where,
in the laminar flow regime, pore channels
of varying lengths and sizes cause
dissemination and mixing of flow elements
(5). As a front of leachate migrates
through the soil, it becomes spread
through dispersion with the production
of the characteristic concentration
gradients decreasing with distance
away from the front. This results in
concentrations less than the leachate
concentration throughout the zone of
dispersion.
For the addition to the soil of
small pulses of contaminated liquid,
dispersion can provide effective
concentration reduction. For step
function additions such as the movemment
of leachate from a landfill, the
effectiveness of dispersion is lessened
as the length of the step function
increases. This is due to the eventual
attainment of full leachate strength.
The effects of dispersion are often
observed at landfill sites (6, 7, 8).
Dilution of groundwater contaminants
can exist through the presence of slow
moving and or stationary pore water in
films or in "dead-end" pores. Depending
on flow conditions, contaminants driven
by concentration gradients diffuse into
this stationary water thus retarding
the movement of the contaminant. This
is the same principle that forms the
basis for thin-layer chromatography and
is referred to as the "chromatographic
effect" in subsequent discussions. As
the rate of flow past this stationary
liquid increases,the extent of molecular
diffusion reduces with the arrival of
the moving front at a point of
observation well before expected. Under
slow flow conditions with molecular
diffusion
-------
SOIL 2
0
200 400
EFFLUENT VOLUME (ml)
2 4
EFFLUENT PORE VOLUMES
600
FIGURE 2. BREAKTHROUGH CURVES FOR SOIL 2, COL 1
v, I000r
E 9
— 900
F 800 ->
S
IDEAL TRACER
Ct in DSR EFFLUENT
FOR SOIL 3
H
Z
UJ
0
z
o
0
ir
LU
o
<
a:
H
Q
z
<
UJ
o
ce
0
— J
X
t \
700
600
500
400
300
200
100
— "O
\
\
\
\
\
\
\x
^\cx
^~~-e)^
^T^1 -^
1 1 1 1 1 1 1 1 1 1
23456
DSR NUMBER
10
FIGURE 3. COMPARISON BETWEEN CHLORIDE ION AND IDEAL TRACER CONCENTRATION
191
-------
The properties of the Soil 2 column
included in part,pore volume (PV) = 104cc,
88% saturation before leachate passage
and approximately 100% saturation after
leachate passage. It can be seen from
the BC for Cl~ that the C/Co =0.5
(normalized concentration) occurred at
0.64 PV well before the discharge of 1 PV.
This was under conditions of near
saturation. Thus, with C/Co - 0.5 at
0.64 PV some stationary water did exist.
The assymetry of the Cl~ BC suggests
that diffusion of Cl~ into the stationary
water did take place but that equilibrium
was not reached. The actual volume of
the stationary water is not known but
from the above discussions was
5 (1 - 0.64) PV = 0.36 PV
In. a mass balance performed on the
breakthrough data, 0.125 mg/gm of Cl~
were retained in the column during the
passage of 2 pulses of leachate (Figure 2
deals with 1 pulse only). Had the entire
pore volume including the stationary
water been saturated with Cl~ at the
leachate concentration, the mass
retained would have been 0.155 mg/gm.
This suggests'on an equivalent basis
that .81 PV were saturated with Cl~ at
the leachate concentration and, thus,
molecular diffusion of Cl"into the
stationary water was not complete.
Subsequent studies to desorb the
columns with water released 0.119 mg/gm
of Cl~ as compared to 0.125 mg/gm.
originally retained. This favourable
comparison attested to the conservative
property of the chloride ion. The
results of additional Cl~ tracer
experiments are shown in Figure 3.
Leachate was passed through the 10 DSR's
in series. The curve represents the
concentration of an ideal tracer based
on the initial concentration of Cl~ and a
knowledge of the soil moisture contents
and their Cl~ content. The excellent
fit further supports the conservative
nature of the Cl~ ion.
Sorption
In this work, sorption was taken
to include all processes in which
contaminants are transferred from the
liquid phase onto or into the solid
phase. Most of the research to date on
the sorption of leachate contaminants
by soil has dealt primarily with cation
exchange.
Griffin et_ al. (1, 10) found that
many of the so-called heavy metals were
actively sorbed onto clay minerals mixed
in various proportions with sand. The
mechanism of removal was identified as
ion exchange increasing in intensity with
increased concentration and pH, Cation
removal was accompanied by Ca release
to the liquid phase. For some of the
metals a limiting concentration was defined
beyond which precipitation of the cation
occurred. As an example, for Pb ion
exchange prevailed as a mechanism up to
pH near 7.5 at which point precipitation
began to dominate as the mechanism of
removal. Sorption isotherms for many
metals were presented. Metals removed
in this fashion included Pb, Cd, Zn, C
and Cr (III). The anionic heavy metals,
Cr (IV), As and Se exhibited .reduced
sorption with increased pH. Korte et al.
(11) described the sorption of ten heavy
metals on various classifications of
surficial soils. Subsequent to contact
with comparatively weak leachate spiked
with single heavy metals, soil columns
were segmented and extracted with water
and with 0.1 N HC1. Generally less than
3% of the sorbed metal was extracted with
water. The ease of extraction with water
'was ranked as:
V >Se>As>Cr>Zn>Ni>Cd>Hg>Cu>Pb.
Fuller and Korte (2) reported that
pH, free ion oxides, soil particle size
and fluid flux had significant effects on
cation removal while CEC aad soil organic
content had none. This is in contrast
to the work of Griffin et_ al. (10) in
which a strong positive correlation between
CEC and cation removal was demonstrated.
Sorption processes beyond ion exchange
have received little attention. Griffin
et al. (10) observed that very little
COD reduction occurred during leachate
passage through their clay-sand mixtures.
Davidson et_ al. (12) reported Freundlichian
adsorption of pesticides on soil.
The EC's of Soil 2 presented in
Figure 2 suggest that sorption was an
active mechanism in contaminant attenuation
in this research. Very similar BC
patterns were exhibited by four additional
192
-------
soils for which column experiments were
completed. The concentrations of both
Ca2* and Mgz in excess of the influent
leachate concentrations signaled the
release of these two cations from the
soil and identified the existence of
cation exchange.
Contaminant attenuation by all
processes operative within the soil
columns was calculated by comparing
the BC for the ion in question with the
Cl- BC. By this method, the amount of
Ca^"*" and Mg2+ desorbed' in Soil 2 for the
length of the EC's given in Figure 1 was
calculated to be 6.94 me<|. The CEC of
Soil 2 was 4.5 meq/100 gm or 29.4 meg/
column.
The data in Table 2 represent cation
removal for Soil 2. Since more cations
were removed on an equivalent basis than
released, the existence of addition
attenuating processes was apparent. The
cations NH^. Mn , K+ and Na (K+ and
Na are not shown in Figure 2) reached
their initial leachate concentration
within the period of investigation. This
indicated that the process(es) responsible
for their removal was regulated by a
maximum capacity. Sorption would
represent such a process. Of the 14.6
meq of cations removed, 6.9 meq appear
TABLE 2. CATION REMOVAL IN SOIL 2
LEACHATE CONG.
CATION mg/1
CATION REMOVAL
(AFTER 4.6 PV)
meq/column
<
4-
K
Na+
Fe2+
Mn
Zn2+
Ca2+
Mg2+
846
532
732
91.9
28.4
15.3
300
168
8.2
2.2
2.7
1.2
0.2
0.1
- 1.2
- 5.7
to have been removed by ion exchange.
The balance were removed by some other
sorption process(es).
Figure 2 shows that no Fe2+ or Zn2"4"
appeared in the effluent from the columns.
Thus it may have been that precipitation
was the mechanism of removal for these
two metals.
Some removal of organic matter
within Soil 2 did take place despite
the fact that Cl~ and COD BC's in Figure 2
are almost coincident. This was due to
the very high initial COD = 28,788 mg/1.
It will be shown subsequently that little
evidence of microbial activity within
the column could be demonstrated. Eowever,
limited sorption of organic matter did
occur. The mass of COD removed was 101 mg
COD/100 gm soil (661 mg/colunn) in contrast
to 125, 52, 34, 22 and 3 mg/100 gm soil
for NHf, Na+, K7, Fe/+ and Ma2*.
Breakthrough curves for soils 1, 3
and 10 are shown in Figures 4, 5 and 6.
Many of the characteristics identified
for Soil 2 are visible in the curves for
these soils:
1.
2.
3.
o_i_ 94.
desorption of Ca and Mg
limited removal of COD
moderate removal of M£ and
2+
4 . . extensive removal of Zn
and Fe2+
It is important to note that partial
breakthrough of Fe2+ occurred in Soil 3
and complete breakthrough in Soil 10.
Partial breakthrough of Zn also
occurred in Soil 10. This suggests that,
for these 2 soils in any case, the
removal of Fe2+ and Zn2 was taking place
by means of some exhaustible process
such as sorption.
Comparisons of contaminant removals
are shown in Table 3. For COD, Fe2+,
K. , Mn2"*" and NH^, there appears to be
a general trend of increased removal with
increased CEC although discontinuities
do exist. The determination of correlation
coefficients was negated by the scarcity
of data.
pH
5.75
7.05
From the foregoing, it would appear
that sorptive processes including ion
exchange played an important, and in many
cases, dominant role in contaminant removal.
193
-------
500 1000
EFFLUENT VOLUME (ml)
1500
0 I
EFFLUENT PORE VOLUMES
FIGURE 4. BREAKTHROUGH CURVES FOR SOIL 1, COL 1
194
-------
0
0
o- ci
• . COD
A - Mn
Z4-
D - Cu
2-f
A - Fe
v- Zn
E-f-
z+
SOIL 3
1000 2000
EFFLUENT VOLUME (ml)
3000
4 6
EFFLUENT PORE VOLUMES
FIGURE 5. BREAKTHROUGH CURVES FOR SOIL 3, COL 1
195
-------
0
L
0
500 10OO
EFFLUENT VOLUME (ml)
A - Fe
v - Zn
2 +
1500
FIGURE 6.
1
EFFLUENT PORE VOLUMES
BREAKTHROUGH CURVES FOR SOIL 10, COL 1
o
(71
cn
E
O
s
u
o:
O.I
(3,3.3)
NUMBERS IN BRACKETS :
(SOIL.CEC)
(9,1.1)
0.01
J_
50 100 500 1000
EQUILIBRIUM NH4+ CONCENTRATION (mg/1)
FIGURE 7.
REMOVAL ISOTHERMS
196
-------
Parameter
TABLE 3. COMPARISONS OF CONTAMINANT REMOVALS BETWEEN SOILS
Contaminant Removed - mg/g
For Soil Number
2 3
1 number in brackets is leachate concentration
2 negative sign signifies contaminant release
10
COD
Fe24
K+
Mn.
„ 2+
Ca
„ 2+
Mg
NH^
CEC meq/lOOg
% < 0.002 mm
.830
(28708) L
.052
(94)
.238
(520)
.016
(29)
-.045
(320)
-.141
(195)
.289
(862)
15.8
7.0
1.01
(28788)
.062
(92)
.132
(532)
.009
(28)
-.085
(300)
-.027
(168)
.224
(846)
4.5
8.0
.63
(31490)
.028
(71)
-.00 72
(559)
.002
(27)
-.299
(630)
-.044
(118)
.086
(915)
3.3
1.7
.492
(35143)
.018
(55)
-.117
(503)
-.006
(33)
-.543
(253)
-.03
(215)
.028
(1030)
1.4
3.1
The dispersed soil reactors (DSR)
were used in addition to the soil columns
to explore contaminant removal in soil.
Isotherms for contaminant removal as a
function of concentration were prepared
from the DSR data and are presented in
Figures 7, 8, 9 and 10 for NHj, Zn ,
COD and K , respectively. Data points
were omitted for the sake of clarity in
the figures. Scatter in the data points
was substantial for some soils.
Figure 7 shows NH^ removal isotherms
plotted in the Freundlich form. These
show a strong trend toward increased
removal with increased CEC. The existence
of a sorptive process, probably'ion
exchange, was assumed to exist. A
similar trend appears in the data for Zn
in Figure 8.
The mechanism of ion exchange
would appear to have been operative
once again although consideration to
precipitation is given subsequently.
In Figure 9, the data for COD
are linear on a simple arithmetic plot.
Data on COD concentrations less than
12,000 mg/1 were not available for Soil 6.
Curves for soils 3,9 and 10 with CEC's of
3.3, 1.1 and 1.4 meq/100 gm respectively
exhibited limited COD removal in the
DSR's. As with NH+. and Zn2"1" removal, a
trend of increased COD removal with
increased CEC suggested an adsorptive
process as the operative mechanism of
removal. The removal of K during leachate
197
-------
in
te.
Q
I o-i
0-05
o
•s.
UJ
-------
0.0
175)
B SOIL 2 CEC = 4.5 meq / iOOg
o SOIL 3 CEC = 3-3 „
A SOIL 9 CEC =1.1
D DENOTES DESORPTION
( ) NUMBERS IN BRACKETS GIVE
CORRESPONDING NH^ CONCENTRATIONS
I
0
200 400 600 800
EQUILIBRIUM K+ CONCENTRATION (mg/l)
FIGURE 10. SORTION OF K+ON SOIL IN OSR
o
o 1-5
<
x.
UJ
o
o
o
1-0
Q
UJ
N
< 0-5
2
OC
O
COL 2 : LEACHATE
COL 3 : WATER
SOIL 2
cr
200 300 400 0 100 200 300 400
EFFLUENT VOLUME (mf)
I i l_j | | | |
2 401234
PORE VOLUMES
FIGURE 11. CONTAMINANT CONCENTRATIONS DURING DESORPTION
199
-------
passage through DSR's for soils 2, 3 and
9 with CEC's of 4.5, 3.3 and 1.1 meq/
100 gm respectively is shown in Figure 10.
At low K+ concentrations, K^ removal
increased with concentration to some
maximum value after which removal fell
off rapidly to zero with further increases
in concentration. This pattern was felt
to be due to competition with other ions
during sorption. The higher K+ con-
centrations occurred coincident with high
concentrations of other cations such as
NH and Fe . Die curves show that the
NHl concentration had reduced from .
900 to near 200 mg/1 before maximum KT
sorption was observed. This form of inter-
dependent sorption was demonstrated for
Na as well as for K7. A somewhat similar
situation existed for Ca and Mg2 since
the release of the ions during exchanges
was followed in some soils by subsequent
removal down flow.
The modelling of this inter-
dependency in contaminant sorption is
a complicated process. The DSR ex-
perimental mode appears to represent an
instructive means for quantifying the
phenomenon.
Precipitation
Griffin e± al. (1, 10) have shown
that, under the conditions of their
experiments, precipitation was operative
in the removal of Pb , ZrT , Hg2+, Cdz ,
Cu2+ and Cr(IV) at pH's above specified
levels. This was supported by the
appearance of metallic hydroxides in the
surfacial regions of their soil columns.
In this research, evidence of the
existence of precipitation was not
apparent. The EC's for Soils 1 and 2
(Figures 4 and 2) show no breakthrough
for Zn2+ and Fe2+ and thus, the possibility
of precipitation exists. However, break-
through did occur in Soils 3 and 10. The
DSR analysis for both metals strongly
suggested the existence of sorptive
processes due to the positive correlation
between the mass of cation removed and the
CEC of the soil (see Figure 8).
Maximum cation solubilities were
calculated for the leachate at pH 5.65.
It was found that only Zn exceeded the
calculated solubility (assuming that iron
and manganese were present in the
divalent form). This was however by a
factor of approximately 10 . This may
have been due to the presence of
complexing agents helping to maintain
Zn in the solution phase.
Upon passage through the soil, the
leachate pH increased to the range from
7.0 to 7.95. In this range, the measured
leachate concentrations of bath Fe and
Mn2+ also exceeded predicted solubilities.
From this analysis, it is apparent
that the potential for the precipitation
of Zn , Fe and Mn2+ did exist. However,
based on the previous discussion, removal
of these metals by sorptive processes
seems to have been the operative mechanism.
Biological Transformations
The results of this research indicated
that biological activity played a minor
role in reducing leachate contaminant
concentrations. The data in Table 3
showed that organic matter (measured as
COD) was removed from the leachate during
passage through the soil. However, this
appears to have been due largely to
sorption of the organics.
For Soils 1 and 2, Table 3 showed
COD removals of 0.836 and 1.01 mg/gm
respectively. These values were calculated
for the complete breakthrough curve thus
yielding COD concentrations equal to
the raw leachate concentration throughout
the soil column (see Figures 2 and 4).
From the isotherms in Figure 9, the
removal of COD would be approximately
0.8 and 0.5 mg/gm respectively. This
would suggest only sorption in Soil 1
and sorption plus some other process in
Soil 2. The other process may have been
biological. Little additional evidence
existed'to support the presence of
biological degradation.
It is reasonable to anticipate the
existence of anaerobic decomposition of
leachate organics in the soil. Pohland
(13) achieved almost complete destruction
of organics during the recycle of leachate
through a landfill. Boyle and Ham (14)
had similar success when treating leachate
by means of anaerobic digestion. Thus,
the leachate organic matter is amenable
to anaerobic decomposition.
It would seem in this research that
the conditions for the development of an
200
-------
anaerobic culture suitable for large scale
organic matter reduction did not exist.
The problem may have been simply one of
insufficient time, first for the
development of the anaerobic culture and
second for it to achieve appreciable
reductions in COD.
Support for this exists in the
results from the DSR experiments. Two
pulses of leachate were passed in
succession through the sequence of
10 DSR's for each soil. The interval
between slugs was on the order of 1
week during which time residual leachate
remained within the soil. The results
for most soils showed an appreciable
increase in COD removal from the second
pulse as compared to the first. It was
concluded that the anaerobic culture
had an opportunity to develop during the
interval and was available to effect
increased COD removal during the passage
of the second pulse.
Filtration
The leachate used in this research
contained suspended solids in very small
concentrations in the order 100 mg/1.
These were absent in the column effluent
and filtration appeared to be the
mechanism of removal.
The potential for cation precipitation
was discussed previously. It was
anticipated that any precipitates formed
would be removed by filtration in the soil
near the point of formation. This is
compatible with the work of Griffin
et al. (1).
Gaseous Exchange
The collection and transportation of
leachate and the subsequent contact with
soil were accomplished under nitrogen gas
in order to maintain anoxic conditions.
The partial pressure of C0_ in the landfill
cell was in excess of 0.5 atmospheres (4)
and thus, CO release from solution was
expected during experimentation.
Measurements to support this were not
made beyond the monitoring of changes in
alkalinity and pH.
No other gaseous release was
anticipated.
MECHANISM STABILITY
In order to test the stability of
leachate contaminant retention in the
soil, water was passed through all soil
columns and DSR's and contaminant
concentrations in the effluents from
these experiments were measured. The
results from the Soil 2 column desorption
experiment are shown in Figure 11.
Once again, Cl~ concentrations were
used to indicate ideal tracer behavior.
The Cl~ discharge curve reflected the
expulsion of leachate remaining in the
soil pores from the leachate contact
experiments.
The data show that, before the
desorption phase, the concentrations of
most of the contaminants had reached the
raw leachate concentration. Upon
desorption, the concentration profiles
exhibited the same general shape as the
Cl~ curve. The curves for K+ and COD are
of particular interest since they begin
at or below C/Co = 1.0, but proceed above
the Cl~ curve and therefore demonstrate
the occurrence of contaminant desorption.
The mass of COD desorbed was calculated
to be 0.47 mg/gm. This compares closely
with 0.5 mg/gm, the COD sorbed on Soil 2
as estimated from the isotherms in
Figure 9. Similar trends were observed
in the data from other soils. It would
appear therefore that the sorptive processes
for COD removal were highly reversible.
O i
Very little desorption of Mn^ or
NH4 is evident in Figure 11. The Fe2+
curve shows virtually no breakthrough at
the end of the leachate contact phase and
no apparent release of Fe during
desorption. The processes responsible
for the removal of these ions appear to
have been stable during the passage of
water through Soil 2.
Desorption was also a part of the
DSR experimental programme. A volume of
water equivalent to the volume of the
leachate pulses was passed through the
DSR's in sequence. Effluent contaminant
concentrations were measured and the mass
of contaminant released calculated. Data
for 9 soils are presented in Table 4 for
Fe2+, NH£, COD and K+ for the first DSR
only. The influence of dilution in
201
-------
TABLE 4, COMPARISONS BETWEEN CONTAMINANTS REMOVED BY AND RELEASED
FROM SOIL NUMBERS: - (IN mg/gm SOIL)
Contaminant
„ 2+
Fe
NH+
COD
K+
(CEC meq/
100 gm)
.132^
-.000
.607
-.052
2.022
-.095
.356
-.053
15.8
.235
-.004
.220
-.030
1.121
-.838
-.244
-.033
4.5
.022
.004
.117
.018
1.943
.630
-
3.3
.204
-.000
.646
-.123
8.696
-1.565
.447
-.163
7.9
.146
-.000
.054
-.048
5.466
.614
.253
-.015
9.3
.246
-.000
.449
-.203
-
.471
-.073
10.1
.161
-.000
.490
-.055
2.854
-2.157
.295
.038
23.9
.185
-.017
.150
.012
-.852
-.171
.037
-.004
1.1
.021
.002
.012
-.017
1.243
-.563
-.312
.011
1.4
data from first DSR in series of 10
leachate contact phase
water contact phase - negative sign indicates desorption
residual soil moisture was subtracted
from the raw data.
The upper number is the mass of
contaminant released during leachate
contact (in mg/gm of soil). The lower
number is the mass of contaminant
released during desorption. Further
contaminant release could be expected
with the passage of additional pulses
of water and consequently the lower
numbers cannot be taken as maxima.
It can be seen that the release
of Fe during desorption was negligible
for all soils. The removal process was
therefore highly resistant to the
desorption condition.
Such was also the case for NH^ in
the majority of the soils. However, in
soils 5, 6 and 10, a large percentage of
the NH^ removed during leachate contact
was released. In Soils 5 and 10, removal
during leachate contact had been small.
In most cases COD release during
desorption was substantial. This supports
statements made earlier in connection
with the reversibility of the COD removal
process. The behaviour of K during
leachate contact varied from 0.471 mg/gm
removed in Soil 6 to 0.312 mg/gm released
to the liquid from Soil 10. This supports
previous conclusions drawn from the K
removal isotherms regarding retardation
due to other ions in solution.
The trends in contaminant release
observed in this research were summarized
as:
slight release:
slight to moderate
release:
Fe
2+
Zn
2+
and Mn
2+
NH* and K+
substantial release: COD and Na
2+ 2+
It was noted that Ca and Mg ,
while actively released during leachate
contact, were in fact removed during
desorption experiments (Figure 11).
The results of the desorption
experiments show that, for many of the
contaminants removed during leachate
contact, release during desorption was
limited. The resultant concentrations
202
-------
in the desorbing water were substantially
less than the initial leachate con-
centrations. The most active desorption
occurred with COD and Na .
Such behaviour supports the existence
of sorptive removal processes including
ion exchange. The very limited release
O i.l-ii v-4- 0 .in
of Fe , Mn and Zn'' during desorption
indicates high selectivity in the exchange
sequence.
THE ROLE OF DSR*S
Assessment of soil-contaminant
interactions can be accomplished in
reduced time using DSR's as opposed to
soil column experiments. This is an
important factor if such information
is required as a prelude to landfill
design.
The disadvantages of the DSR's are
that they do not simulate the hydraulic
conditions of leachate migration in the
field in particular dilution and
dispersion. Neither do they allow for
the development of the microbial
population that would occur in situ.
Their application appears to be in
providing relationships such as sorption
isotherms for non-biological contaminant
removal mechanisms. The deduction of
such relationships from column experiments
requires that dilution and dispersion
including the chromatographic effect be
factored out. At present this is an
uncertain activity.
Computer models were prepared for
both the column and the DSR experiments
to account for the influence of dilution
and dispersion on contaminant con-
centrations. This involved the use of
elemental matrix models calibrated by
using Cl~ as a tracer. Concentrations
during contact were adjusted to reflect
reductions due to soil contact only
and not dilution and dispersion. The
models were run for Soils 1, 2, 3, 9 and
10 and the results presented Figures 12,
13, 14, 15 and 16,respectively.
Contaminants chosen for comparison were
Cl~, COD, NH£ and Zn2+. Normalized
concentrations were plotted against the
soil: leachate contact ratio, gm of
soil per ml of leachate. The complete
column data are presented as are the data
points for the first 4 DSR's.
The data show generally good
agreement between the 2 experimental
modes. They tend to endorse value of
DSR data in providing relationships
describing soil-contaminant interactions
for use in modelling in situ behaviour.
CONCLUSIONS
The following conclusions were
drawn from the results of the column and
DSR experiments:
1. Contaminant concentrations at the
leachate front were reduced through
the mechanisms of dispersion and
dilution. These could function
effectively with the additions of
small pulses of contaminant to the
soil.
2. Sorption was the most active
contaminant attenuation mechanism
observed in this research. Trends
of increased contaminant removal in
soils of increased CEC were demonstrated
for NH4, K , Fe2+, Zn , to2* and COD.
Ion balances showed that sorption
processes in addition to cation
exchange were operative.
3. Increased pH during soil contact
created the potential for Fe2"1", Mn24"
and Zn precipitation.
4. Limited removal of- organic matter
by microbial activity was demonstrated.
5. Desorption studies demonstrated only
slight release of Fe2+, Zn2* and Mn2+
to water, slight to moderate release
of NH4 and K and substantial release
of COD and Na+.
203
-------
o
o
2.00
1.60
y 1.20
O <
o
u
N
0.80
< 0.40
tr
o
0.00
Cl
-
-
X
x
^ » • • i
-
-
1
COD
* 3». x x '
SOIL #\
• COL 1
x BAT 1
i
NH3
. i
.
*
x
1 V
Zn
i
•
f
* x 1 »
Mg
X
X
X
•
1
-
, . 1
50 50 50 50 5
SOIL/LEACHATE CONTACT RATIO ( g/ml)
FIGURE 12. COMPARISONS BETWEEN COLUMNS AND DSRS: SOIL 1
O
O
3.00^
2.60
2.20
1.80
1.40
1.00
p
O
Q
UJ
cr
o
O
Q
K
CC
2
UJ
2
O
u
Q
o:
o
l.tU
1.20
mo.
0.80
0.60
0.40
0.20
0.00
Cl
«- * • x • '
X
-
-
i
COD
i • • i
x •
X
SOIL #2
• COL 1
x BAT 1
1
NH4
i
X
.
X
X
1
Zn
.
1
... x 1 x
Mg
-
-
•
.
• X
X
X -
1 . 1
2.00
1-80
1-60
1.40
1.20
1.00
50 50 50 50 5
SOIL/LEACHATE CONTACT RATIO (g/ml)
FIGURE 13. COMPARISONS BETWEEN COLUMNS AND DSRS: SOIL 2
o
O
Q
i—
-------
.-, "•*HJ
0
x_
H 1-20
O
H 1.00'
<
(T
g 0.80
0
o
<~> 0.60
Q
Ld
n 0.40
^
^
0 0-20
z
0.00
Cl
- X*W»x 1
-
-
-
—
i
COD
I >*• XI
*x
SOIL#3
• COL 1
x BAT 1
i
NH3
* *
^
•x
x
1
Zn
•
5*
X
. 1 X
Mg
-
-
X
-
"3
0
o
2.00 —
—;,
5
Jl-80 ^
* 1 o:
£
x 4J.60 H
I ^
o
-
•
•
-
—
! 1
1-40 Q
Ld
N
1.20 <
2
6
1.00 ^
50 50 50 50 5
SOIL/ LEACHATE CONTACT RATIO (g/ml)
FIGURE 14. COMPARISONS BETWEEN COLUMNS AND DSRS: SOIL 3
O
o
^L
O
h-
cc
LU
O
O
o
LJ
cc
o
2.00
1.60
1-20
0.80
0.40
0.00
Cl
-
—
—
I
X -X X
t- » • • 1
-
_
~
-
1
COD
X
1 >
• \s V
X *
t *
SOIL #9
• COL 1
x BAT 1
i
NH3
i i
x x
X
•
* •
i
Zn
X
1
.
X
•
!
Mg
-
-
-
•
•
*
_
_
x
oc
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O
2-60 H
2.20 y
2:
0
o
1.80
Q
UJ
N
1.40 ^
^ —
x O
„ , i i 1.00 2
50 50 50 50
SOIL/LEACHATE CONTACT RATIO (g/ml)
FIGURE 15. COMPARISONS BETWEEN COLUMNS AND DSRS: SOIL 9
205
-------
I.«+U
o
o
^ 1.20
o
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Z
0 1.00'
h-
o:
tjj 0.80
LJ
Z
g 0-60
Q
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M 0.40
_j
<
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g 0.20
2
0.00
Cl
- X
-
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1- •• • 1
-
—
-
-
-
-
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COD
« >< >
X y s£
•
SOIL * 10
• COL 1
x BAT 1
,
NH3
i i
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X
1
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X
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y
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™
-
™
_
-
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-
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i 1
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c
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cc
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rsi
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50 50 50 50 5
SOIL/LEACHATE CONTACT RATIO (g/ml)
FIGURE 16. COMPARISONS BETWEEN COLUMNS AND DSRS: SOIL 10
206
-------
REFERENCES
1. Griffin, R.A., Cartwright, K. and 10.
Shimp, N.F., "Attenuation of
Pollutants in Municipal Landfill
Leachate by Clay Minerals".
Environmental Geology Notes, Number
78, Illinois State Geological Survey,
November 1976.
2. Fuller, W.N. and Korte, N.,
"Attenuation Mechanisms of Pollutants n.
Through Soils". Gas and Leachate
from Landfills, Formation, Collection
and Treatment. Proceedings of a
Research Symposium, Rutgers University,
New Brunswick, New Jersey, March 1975.
3. Farquhar, G.J. and Rovers, F.A.,
"Leachate Attenuation in Undisturbed
and Remoulded Soils", Gas and Leachate
from Landfills, Formation, Collection 12.
and Treatment. Proceedings of a
Research Symposium, Rutgers University,
New Brunswick, New Jersey, March 1975.
4. Rovers, F.A. and Farquhar, G.J.,
"Infiltration and Landfill Behaviour ",
ASCE, Journal of the Environmental
Engineering Division, 99, EE5, 13.
October 1973.
5. Coats, R.H. and Smith, B.D., "Dead-End
Pore Volume and Dispersion in Porous
Media". Soc. of Petrol. Eng. Journal,
March 1964.
6. Farquhar, G.J., Rovers, F.A., 14.
Farvolden, R.N. and Mill, N.M.,
"Sanitary Landfill Study Final
Report: Volume I Field Studies",
University of Waterloo Research
Institute, 1972.
7. Rovers, F.A., Farquhar, G.J. and
Nunan, J.P., "Landfill Contaminant
Flux-Surface and Subsurface Behaviour".
21st Industrial Waste Conference, MOB,
Toronto, June 1973.
8. Crutcher, A.J., Sykes, J.F.,
Farquhar, G.J. and Rovers, F.A.,
"Evaluation of Landfill Leachate
Monitoring Data", Interim Report
to Environment Canada, January
1977.
9. Oakes, D., "Personal Communications",
Water Research Centre, Medmenham,
UK, February 1976.
Griffin, R.A., Frost, R.R. and
Shimp, N.F., "Effect of pH on
Removal of Heavy Metals from
Leachate by Clay Minerals". Residual
Management by Land Disposal,
Proceedings, of Hazardous Waste
Research Symposium, Tucson, Arizona,
February 1976.
Korte, N.E., Fuller, W.H.,
Niebla, E.E., Skopp, J. and
Alesii, B.A., "Trace Element Migration
in Soils: Desorption of Attenuated
Ions and Effects of Solution Flux".
Residual Management by Land Disposal,
Proceedings of Hazardous Waste
Research Symposium, Tucson, Arizona,
February 1976.
Davidson, J.M., Ou, L.T. and
Rio, P.S.C., "Behaviour of High
Sesticide Concentrations in Soil
Water Systems". Residual Management
by Land Disposal, Proceedings of
Hazardous Waste Research Symposium,
Tucson, Arizona, February 1976.
Pohland, F.G., "Landfill Management
with Leachate Recycle and Treatment:
An Overview". Gas and Leachate from
Landfills, Formation, Collection
and Treatment. Proceedings of a
Research Symposium, Rutgers University,
New Brunswick, New Jersey, March 1975.
Boyle, W.C. and Ham, R.K., "The
Treatability of Leachate from
Sanitary Landfills". Journal, Water
Pollution Control Federation, 46,6,
June 1974.
207
-------
ATTENUATION OF PCB'S BY SOIL
MATERIALS AND CHAR WASTES
R. A. Griffin and A. K. Au
Illinois State Geological Survey, Urbana, Illinois
E. S. K. Chian and J. H. Kim
University of Illinois, Urbana, Illinois
F. B. DeWalle
Stanford University, Stanford, California
ABSTRACT
Adsorption of polychlorinated biphenyl (PCB) isomeric mixtures containing 42 and
54 percent chlorine by montmorillonite clay and soil and the relative mobility of these
compounds through soil media were" determined by both gas chromatography and C labeling
techniques. Adsorption by these earth materials was found to be strong with more than 90
percent removal from solution at concentrations approaching the water solubility of the
compounds tested.
PCB's were found to be immobile in earth materials when measured by the soil
thin-layer chromatography technique. R, values for PCB's were found to be zero to 0.02
for all amounts of PCB's tested (42-206 ng). Dicamba, a pesticide with high mobility, was
used as an internal standard and yielded Rf values of 0.80 to 1.00.
Gas chromatographic analytical procedures that allowed improved quantitative
measurement of PCB's in aqueous solutions were developed. The overall perchlorination pro-
cedure for conversion of isomeric mixtures of PCB's to the fully chlorinated biphenyl by
digestion with SbCls was successfully reduced from approximately 20 steps to about 10 steps.
The speed of the analyses was improved and interference from bromine was removed. Repro-
ducibility of the overall perchlorination with 80 ng biphenyl in sealed glass tubes was
determined to be 0.52 percent relative standard deviation.
INTRODUCTION
Polychlorinated biphenyls (PCB's) are
used in a wide range of industrial appli-
cations such as electrical insulation, fire-
resistant and heat transfer fluids, hy-
draulic fluids, high temperature and pres-
sure lubricants, sealants, expansion media,
adhesives, plasticized paints, lacquers,
varnishes, pigments, paper coatings, waxes,
and as constituents in elastomers. They
were largely ignored as environmental con-
taminants until Jensen (1) and Widmark (2)
identified them in 1966. PCB's did not
attract much concern as hazardous chemicals
until the incidents of contaminated cooking
oil in Japan in 1968 and of contaminated
chicken feed in the United States in 1971
(3). Laboratory studies with animals have
shown that PCB's can cause enlargement of
the liver, induction of hepatic microsomal
enzymes, reproductive failures, gastric dis-
orders, skin lesions, and tumors in birds
and "mammals (3). The 2000 afflicted Japanese
people in the "Yusho" incident of 1968 ex-
perienced lesions of the skin, facial
swelling, and neurological disorders that
were similar to the results reported in the
animal studies (4).
Fish and other aquatic organisms tend
to accumulate PCB's in lipid-rich tissues
and organs. Predators at the top of the
food chain may accumulate PCB's to levels of
more than 107 times that of the ambient
water (4). Man usually resides at the top
of the various food chains and, due to the
biological magnification, may ingest large
amounts of PCB's even though only trace
amounts are present in the ambient waters.
208
-------
PCB's have, therefore, been considered as a
significant hazard to human health as well
as the environment.
PCB's have been manufactured in the
United States since 1929; it has been esti-
mated that more than 400,000 tons have been
produced since that time. The sole U.S.
manufacturer of PCB's is the Monsanto Com-
pany located near East St. Louis, Illinois.
Since 1971, Monsanto voluntarily has re-
stricted its sales of PCB's to only "closed"
systems, such as PCB-containing insulating
fluids used in electrical transformers and
capacitors. These two applications account
for essentially all the current use of PCB's
in the United States (5). On October 5,
1976, Monsanto announced that it would cease
to manufacture and distribute PCB's by
October 31, 1977. A timetable set by the
U.S.-EPA has called for a gradual phasing
out of PCS manufacturing by January 1, 1979,
and a ban on all PCB processing or distri-
bution in commerce by July 1, 1979 (6).
These steps have significantly reduced the
introduction of PCB's into the environment.
Unfortunately, approximately one-half
million pounds of PCB's are still imported
into the U.S. each year from foreign manu-
facturers and millions of pounds of PCB's
still exist causing the environmental levels
to remain quite high. For example, two
tributaries of Lake Michigan have PCB levels
that consistently exceed 100 ppt. This has
contributed to PCB levels between 4 and 10
ppt in certain parts of the lake. The pres-
ent U.S.-EPA recommended water quality cri-
teria is less than 1 ppt and the high PCB
levels have caused great concern to the res-
idents of Chicago, who draw their drinking
water from the lake (4).
Many companies discard their old elec-
trical equipment in unapproved places and
thus discharge the PCB's into the atmosphere
and waterways. One problem of disposal in-
volves the high costs and fees for trans-
porting PCB wastes to regional incinerators
or approved landfills vs. simply discarding
the wastes. Incineration is considered the
safest method for disposal of PCB wastes.
However, this method is extremely costly and
has some operating difficulties. PCB's do
not burn readily and, under improper oper-
ating conditions, can be vaporized during
incineration. Thus, incineration may turn
out to be the major source of PCB's re-
entering the environment. In addition,
large electrical transformers and capacitors,
the major source of waste PCB's, cannot be
satisfactorily incinerated.
Thus, land disposal is the only rea-
sonable alternative for waste PCB's. Al-
though landfill disposal appears to be the
most acceptable alternative, little infor-
mation is presently available concerning the
possibility of ground-water contamination by
leaching PCB's from landfills. Lidgett and
Vodden (7) analyzed waters around a sanitary
landfill for PCB's and found the contamina-
tion levels to be below their detection
limit of 4 ppb. Similarly, Robertson and
Li (8) failed to detect PCB's in ground
water using GC/Mass Spectrometry techniques.
Tucker, Litschgi, and Mess (9) studied the
leaching of Aroclor 1016 from various types
of soils and concluded that PCB's are not
readily leached from soil by percolating
water.
The paucity of information available
shows no evidence that ground waters have
become contaminated by PCB's. However, many
surface waters do contain PCB's and the
mechanism of transport in the biosphere and
the mechanism of attenuation in soil are
still unknown. Data on the factors affect-
ing PCB attenuation by earth materials would
provide a rational basis for future disposal
site selection and design.
BACKGROUND
The research reported here is supported
in part by Grant R-804684-01, from the U.S.
Environmental Protection Agency, Municipal
Environmental Research Laboratory, Solid and
Hazardous Waste Research Division, Cincinnati,
OH 45268.
The purposes of the present project are:
a) To conduct an extensive literature review
of pertinent information on the adsorption
of hazardous organic compounds;
b) To measure the adsorption capacity of se-
lected earth materials for pure PCB's and
PCB wastes;
c) To quantitatively evaluate the effects of
pH, biological degradation, photodecomposi-
tion, volatilization, time, and adsorbent
structure on adsorption of PCB's;
d) To use this data to develop a mathemati-
cal model that will allow prediction of PCB
adsorption and mobility; and
e) To further develop analytical procedures
that will allow improved quantitative meas-
urement of PCB's contained in aqueous solu-
tions .
209
-------
PCB Materials
Adsorbents
Polychlorinated biphenyls (PCB's) is a
generic term applied to certain mixtures of
synthetic organic compounds. These com-
pounds are mixtures of very closely related
isomers and homologs that contain two phen-
yl rings with 10 possible chlorine attach-
ments. The biphenyl structure is shown in
Figure 1. PCB's are made by substituting
chlorine atoms for one or more of the hy-
drogen atoms at the numbered positions of
the biphenyl structure. These compounds
are chemically and thermally stable, very
resistant to microbial degradation, and are
highly persistent in the environment.
6' 5'
Fig. 1. BIPHENYL STRUCTURE: Positions
2 co 6 and 2' to 6' indicate ten
possible positions for chlorine
substitution. Different amounts
of chlorine substitution form
the various PCB's.
The PCB materials chosen for study were
the pure Aroclors 1242 and 1254 (42 and 54%
substituted chlorine, respectively) sup-
plied by the Monsanto Company, and the C
labeled compounds were prepared by New
England Nuclear Corporation. Gas chroma-
tographic traces of the l>tC labeled com-
pounds were identical to those of the pure
Aroclors 1242 and 1254, respectively.
Therefore, it was assumed that there were
no significant differences in the respec-
tive compounds and that the ll4C labeled and
pure Aroclors would behave similarly in
studies of adsorption, mobility, and micro-
bial degradation.
A used capacitor fluid was also ob-
tained for study. The fluid was drained
from a burned out 50 KVA capacitor manufac-
tured by Westinghouse in 1966 and original-
ly contained Aroclor 1242. This capacitor
was supplied by Illinois Power Company and
was scheduled to be landfilled. We believe
this fluid is representative of the type of
PCB wastes that are normally disposed of in
landfills.
Ear.th materials, representing a wide
range in characteristics, have been se-
lected as adsorbents. The materials being
studied are: Ottawa silica sand; Panther
Creek southern bentonite clay; the soils,
namely Bloomfield Is, Ava sic, Cisne sil,
Flanagan sil, Catlin sil, Drummer sicl,
Weir sic, a calcareous loam till; and two
coal chars. The chars were selected be-
cause of their high adsorption capacity for
organic compounds. They are a waste prod-
uct of many coal conversion processes and
thus have potential use as a liner material
for disposal sites accepting organic wastes.
Analytical Development
In general, PCB's are determined quan-
titatively by comparing gas chromatographic
(GC) response patterns of a multicomponent
environmental sample with commercial PCB's
(Aroclors) or a mixture of Aroclors. This
technique is limited by the sensitivity and
reproducibility of comparisons of the large
number of peaks produced by the various PCB
isomers. The procedure is further compli-
cated because the various components of
water soluble PCB's contained in environ-
mental samples are not likely to have the
same composition as those in the original
Aroclor used as a reference compound. For
practical reasons, the quantitation is usu-
ally done by integration of the major peaks
while ignoring the minor peaks. This can
cause some error, depending on how well the
mixture of isomers in an unknown sample
compares to a standard.
Because of these problems, we have de-
veloped procedures that allow improved
quantitative measurement of PCB's in aque-
ous samples. The main thrust of our
studies has been to improve previous pro-
cedures whereby isomeric mixtures of PCB's
were converted to the fully chlorinated bi-
phenyl, decachlorobiphenyl (DCB), by di-
gestion with SbCls- This procedure has the
advantage of converting all the PCB's to a
single peak for improved quantitation. The
electron capture GC detector is many times
more sensitive to DCB than it is to PCB's;
thus, the conversion to DCB improves the
sensitivity and lowers the detection limit
for PCB's.
210
-------
CURRENT STUDIES OF PCB ATTENUATION
AND ANALYTICAL DEVELOPMENT
PCB Mobility
The technique of determining pesticide
mobility in soils by soil thin-layer chro-
matography was introduced in 1968 by
Helling and Turner (10). Since the intro-
duction of the technique, the mobility of a
large number of pesticides in a variety of
soils has been tested (11, 12, 13). Soil
thin-layer chromatography, or soil TLC, is
a laboratory method that uses soil as the
adsorbent phase and water as the developing
solvent in a TLC system. The system is
relatively simple and yields quantitative
data on the mobility of organic compounds
in soils that appear to correlate well with
trends noted in the literature (10). The
results reported here are mobility data for
Aroclor 1242 and 1254 on TLC plates made
from sand, clay, three soils, and a coal
char. Dicamba, a pesticide of known high
mobility, was used as an internal standard.
The soil sample was slurried with water
until moderately fluid, and then was ap-
plied with a spreader to clean glass plates
20 cm by 20 cm square. The soil was spread
to a thickness of 0.5 pom and then air dried.
A horizontal line was scribed 12 cm above
the base to stop water movement; vertical
lines were scribed 2 cm apart to separate
the various treatments. The compounds were
spotted 2 cm from the base and leached 10
cm with water. The activity of the l>tC la-
beled compound varied between 11,000 and
44,000 dpm. The plates were immersed in
0.5 cm of water in a closed glass chamber
and were removed when the wetting front
reached the horizontal line. Leaching was
thus ascending chromatography. The soil
plate was then removed and air dried. A
piece of 8 x 10 inch medical X-ray film was
placed in direct contact with the soil
plate for approximately one week. The re-
sultant autoradiograph indicated the rela-
tive movement of the compound, which was
measured as the frontal R. of the spot or
streak.
Figure 2. shows the results of PCB and
Dicamba mobility on Catlin soil plates.
The figure is a composite of data from two
plates illustrating the low mobility of the
two PCB's at four concentrations and the
excellent replication of the Dicamba mobil-
ity. The amounts of PCB spotted in each
lane is labeled on the figure and ranged
from 42 to 206 ng. It is clear that at all
four amounts PCB's remained at the origin,
were immobile in Catlin soil, and the Di-
camba had an Rf of between 0.85 and 0.90.
The R, is defined as the distance the com-
pound moved relative to the distance the
water front moved; that is, the Dicamba
moved 85 to 90 percent of the distance the
water front moved on the plate. The two
PCB's had R,. values of zero.
The R values obtained for Aroclor 1242
and 1254, and for Dicamba on TLC plates
made with several earth materials are pre-
sented in Table 1. The results clearly in-
dicate that the two PCB's tested are highly
immobile in these test systems. Rf values
of zero to 0.02 were obtained for all the
materials tested, even the pure silica sand.
Dicamba was shown to be highly mobile in
these tests with R, values ranging from
0.80 in the char to 1.00 in the sandy ma-
terials .
Adsorption Studies
Equilibrium adsorption studies were
carried out by shaking known volumes of PCB
solutions with varying weights of earth ma-
terials at a constant temperature of 25°C.
Figure 3 shows representative results for
adsorption of Aroclor 1242 and 1254 by
montmorillonite clay. Weights of clay var-
ied from 0.01 to 0.5 g per 10 ml of solu-
tion. Blanks containing no clay were car-
ried through the experiment. The data in
Figure 3 indicates that more than 50 per-
cent of the PCB's were removed in the
blanks (no clay). The reaction was carried
out in sealed centrifuge bottles so that
volatilization and losses during separation
of the solid from the liquid phase were
minimized. Since PCB's are highly resist-
ant to microbial degradation, the results
are interpreted as adsorption of the PCB's
onto the glass walls of the centrifuge bot-
tle. This strong adsorption by the glass
container is consistent with the observa-
tion that PCB's were immobile on the silica
sand TLC plates described above. Adsorp-
tion by 0.5 g of clay is nearly complete
with less than 1 ppb remaining in solution.
It was concluded that PCB's are strongly
adsorbed by earth materials. This conclu-
sion is consistent with the high degree of
immobility observed in the soil TLC study.
Analytical Procedure Development
Little effort has been made to derive
211
-------
Aroclor
Aroclor
no
ro
1.0
.9
8
7
.6-
.5-
.4-
.3-
.2-
1242
1 1 , 000 dpm
42 ng
P
'
•
1242
22,000 dpm
84 ng
1
'
1
I
1
I
•
1242
33,000 dpra
126 ng
i
•
i
»'
•
1242
44,000 dpm
168 ng
i
.1
Dicamba
23,000 dpm
355 ng
I
9
*
1254
11,000 dpm
52 ng
i
•
1254
22,000 dpm
104 ng
•
r
•«
1254
33,000 dpm
156 ng
If
I
^^^^^^BB 4*1,
1254
44,000 dpm
208 ng
mm
Dicamba
23,000 dpm
555 ng
•1
i
i'
.
v
*
t
I
- *
•
Fig. 2. PCB and Dicamba mobility in water on Catlin sil soil thin-layer chromatography plates.
-------
Table 1:
Earth
Material
Mobility of Aroclors 1242 and 1254 and
Dicamba in Earth Materials as Measured
by Soil Thin-Layer Chromatography.
Compound
Aroclor
1242
.02
.01
.00
.00
.00
.00
Aroclor
1254
Rf
.02
.01
.00
.00
.00
.00
Dicamba
1.00
1.00
1.00
.88
1. 00
.80
Silica sand
Bloorafield Is
Ava sic
Catlin sil
Montmorillonite
Coal Char (1200°F)
the PCS residue to a single compound for
quantification. The attempted derivatives
were biphenyl and decachlorobiphepyl (DCB).
The former derivative could be obtained by
catalytic hydrogenation of PCB's (14, 15).
The main disadvantage of this approach is
that the derivative, biphenyl, is deter-
mined with flame ionization detector (?ID)
on GC, which decreases the sensitivity of
the detection system.
Procedures have been established to
convert PCB's to perchlorinated PCB, DCB,
by Armour (16). In brief, an extracted
PCB residue with 0.2 to 0.5 ml antimony
pentachloride in ~0.1 ml chloroform was
subjected to heating at 170° for 4 to 15
hours. The reaction vessel used was 10 OD
mm x 150 mm (internal volume ~7.5 ml) re-
sealable glass tubes; heat was applied to
one third of the tube length during the
reaction. At the end of the heating the
excess SbClg was decomposed with 6N HC1,
followed by hexane extraction of DCB for
GC analysis. Overall perchlorination re-
action requires approximately 20 steps.
The procedure has been subjected to
further study by Trotter (17) and the limi-
tations on the use of SbClj for perchlori-
nation of PCB's were discussed. Commer-
cially available SbCl5 is contaminated with
traces of Br, likely as antimonybromotetra-
chloride. The presence of the Br contami-
nants is believed to be the source of bro-
monanochlorobiphenyl (BNCB), which was a
likely competing product with DCB during
perchlorination.
Based on the above information, our
efforts have been directed toward modifica-
tion of the perchlorination procedure by:
1) Increasing the amount of solvent used
during perchlorination,
2) Removing the Br interference,
3) Reducing the overall number of reaction
steps.
The gas chromatographic column used in
this study consisted of a 2 mm ID x 1.83 m
glass column packed with 4% SE 30/6% OV-210
on 80/100 mesh chromosorb WHP. The column
temperature was held isothermally at 260°C.
The detector used was a Hewlett Packard
linear 63M electron capture (BCD) with ni-
trogen as a carrier gas. The attenuation
of the gas chromatograph was set at 1 x 4
with which full-scale recorder deflection
was observed with 100 ng DCB.
For the gas chromatographic quantifica-
tion, Mirex was used as an internal stan-
dard. Reproducibility of gas chromato-
graphic quantitation of DCB with Mirex as
an internal standard will be discussed in
the later part of this section.
By increasing the amount of perchlor-
ination solvent, loss of extracted PCB's
can be avoided during concentration of the
extracts (18). Also, a larger volume of
solvent will maintain reflexing inside the
reaction vessel resulting in complete •
mixing of PCB's and the perchlorinating re-
agent, SbCls.
When 2 ml of a mixture containing equal
amounts of CHCls and SbCls was heated over-
night at a heating block temperature of
220°C, interfering gas chromatographic
peaks were observed. The interfering GC
peaks may result from a reaction between
the SbCls and the CHClj, or between SbCls
Fig. 3. Adsorption of Aroclor 1242
and 1254 "by montmorillonite at
25°C.
213
-------
A
B
CM
CO
rd
CO
CD
CT>
00
CD
CM
CO
ro
E S
ro N-"
0>
CM
CM
ro
CM
DL
O
h-
co
Fig. A. Gas chromatography traces for PCB analysis. A) Interference caused
by Br and incomplete perchlorination. B) Complete perchlorination show-
ing disappearance of Br interference, C) Analysis of actual water sample
using perchlorination procedure.
214
-------
and the CaHsOH that is present in CHCls as
a preservative. Further, the use of CHaCla
gave a similar result. However, CCli, did
not react with SbCls under the given reac-
tion conditions.
for a water sample processed by the proce-
dure shown in Figure 5.
PCS ANALYTICAL PROCEDURE
A close examination of the distribu-
tions of the reaction products DCB and BNCB
reveals that the halogenation steps are re-
versible. When a mixture of 0.5 ml of
SbCls and 80 ng of biphenyl in 1 ml of CCli,
was reacted at 220°C for different periods
of time, the distribution of these products
also changes . BNCB is believed to be
formed from the reaction between biphenyl
and SbBrCli, , which is present as an impuri-
ty in SbCl5. The ratios of DCB and BNCB
vs. reaction times are given in Table 2.
Table 2:
Effect of Reaction Time on Formation
of DCB and BNCB.
Reaction time
4 hours
8 hours
25 hours
% ofDCB Formed
83
93
96
% of BNCB Formed
17
7
4
It is clear that a longer reaction time
favors the formation of DCB over BNCB and
indicates that the initial formation of
BNCB is a kinetically controlled reaction.
Further reaction time shifts the unstable
BNCB to the more stable compound DCB—that
is, it is a thermodynamically controlled
reaction. Figure 4A shows that when the
reaction is incomplete the BNCB peak ap-
pears at 8.6 on the GC trace. When the re-
action is complete, BNCB does not appear on
the GC trace (Fig. 4B). Thus interference
from Br can be el'iminated by complete reac-
tion in the perchlorination step. Further-
more, the appearance of the BNCB peak indi-
cates that complete perchlorination is not
achieved in the particular sample.
The overall perchlorination procedure
of PCB's was successfully reduced to ap-
proximately 10 steps by modifying the usual
methods of liquid-liquid extraction and
evaporation of the solvent. This new tech-
nique now only requires 15 to 20 minutes to
prepare a finished sample after perchlorin-
ation of PCB's. The detailed procedure is
shown in Figure 5. It was found that the
sample reaction temperature must be at
least 180°C for more than 16 hours to
achieve complete reaction and destruction
of BNCB. In our studies, this procedure
required a heating block temperature of
240°C. Figure 4C shows a typical GC trace
SAMPLE
200-500 ]li
Extract in CCli,
Add 0.5-0.7 ml
SbCls
Heat sample to
180° C for 16-24 hrs
Add 1 ml CCli, and
4 ml 6N HCl
Quantitatively spike with Mirex
in benzene ( ~4 ml)
Shake
Transfer organic layer
over NaSOi,/NaHC03 crystal
KD to ~ 0.8 ml
at 100° C
2 KD's with
4 ml Benzene
Adjust vol. in Hexane
to fit GC conditions
Fig. 5. Schematic block diagram of
procedures used in PCB analysis
by perchlorination with
The reaction step was initially carried
out in glass sealed tubes and excellent re-
producibility was obtained. Table 3 shows
representative results from four runs where
a relative standard deviation of 0.52 per-
cent was obtained. However, the glass
sealed tubes were subject to explosion and
created a safety hazard to workers in the
laboratory. Therefore, the glass tubes
were replaced with the teflon plugged reac-
tion tubes shown in Figure 6; the teflon
plugged tubes were more convenient and
safer to use. However, Table 3 shows that
215
-------
Table 3: Perchlorination of Biphnyl to DCB.
REFERENCES
Sample
1
2
3
4
Glass Sealed
58.7
58.8
59.0
59.4
Teflon Sealed
69.1
72.8
74.8
66.8
RSD = 0.52%
RSD = 5.0%
much more variability in the data was ob-
tained. The relative standard deviation
from replicate samples is 5 percent. This
accuracy is satisfactory for most routine
analysis, but we are working to find ways to
improve this procedure further.
Fig. 6. Teflon plugged reaction ves-
sel used in perchlorination re-
action.
1. Jensen, S., A New Chemical Hazard: New
Sci. 32:612. (1966).
2. Widmark, G., Possible Interference by
Chlorinated Biphenyls: J_. Assoc. Of fie.
Anal. Chem. 50:1069. (1967).
3. Nelson, N., Panel on Hazardous Trace
Substances, Polychlorinated Biphenyls -
Environmental Impact: Env. Res. 5:249.
(1972).
4. Illinois Institute for Environmental
Quality, Polychlorinated Biphenyls
(PCBs): Health Effects and Recommenda-
tions : Env. Health Resource Center News
No. 20, May 1976.
5. American National Standards Committee,
Askarel Committee Responds to PCB Peril:
ANSI Reporter 10:3. (1976).
6. Outlook, Legislation: The Toxic Sub-
stances Control Act is Effective This
Month: Env. Sci. and Tech. 11:28.
(1977).
7. Lidgett, R. A., and H. A. Vodden, PCB -
The Environmental Problem, in PCB Con-
ferences, Venner-Gren Center: National
Environmental Protection Board, Stock-
holm: Sept. 29, 1970, p. 88-96.
8. Robertson, J. M., and E. C. C. Li, Or-
ganic Leachate Threatens Ground-water
Quality: Water and Sewage Works, Feb.
1976, p. 58-59.
9. Tucker, E. S., W.. J. Litschgi, and W. M.
Mess, Migration of Polychlorinated Bi-
phenyls in Soil Induced by Percolating
Water: Bull. Environ. Contain, and
Toxicol. 13:86-93. (1975).
10. Helling, C. S., and B. C. Turner, Pesti-
cide Mobility: Determination by Soil
Thin-Layer Chromatography: Science 162:
562-563. (1968).
11. Helling, C. S., Pesticide Mobility in
Soils I. Parameters of Thin-Layer
Chromatography: Soil Sci. Soc. Am.
Proc. 35:732-737. (1971).
12. Helling, C. S., Pesticide Mobility in
Soils II. Applications of Soil Thin-
Layer Chromatography: Soil Sci. Soc.
Am. Proc. 35:737-743. (1971).
216
-------
13. Helling, C. S., Pesticide Mobility in
Soils III. Influence of Soil Proper-
ties: Soil Sci. Soc. Am. Proc. 35:743-
747. (1971).
14. Asai, R., et al., J_. Agri. Food Chem.
19:396-398. (1971).
15. Berg, 0. W., et al., Bull. Environ.
Contam. Toxicol. 7:338-347. (1972).
16. Armour, J. A., J. AOAC 56:987-993.
(1973). '
17. Trotter, W. J. , ,J. AOAC 58:466-468.
(1975).
18. Webb, R. G., Isolating Organic Water
Pollutants: EPA Publication EPA-660/4-
75-003, June 1975, p. 11-17.
23.7
-------
VEGETATION KILLS IN LANDFILL ENVIRONS
Franklin B. Flower
Ida A. Leone
Edward F. Oilman
John J. Arthur
Cook College - Rutgers University
New Brunswick, If.J. 08903
ABSTRACT
Much or the organic matter in refuse landfills biodgrades anaerobically producing
primarily methane (CH,) and carbon dioxide (CO ). The death of vegetation above and
adjacent to buried refuse has been associated with the presence of these gases in the
soil atmosphere.
Data obtained from surveying a number of landfill vegetation sites throughout the
United States are reported. Preliminary indications are that the death of the vegeta-
tion is associated -with anaerobic soil conditions caused by the landfill gases. Methods
for evaluating the potential for landfill vegetation growth problems are presented along
with suggested control measures to reduce these vegetation losses.
landfill Gas Generation and Movement
Prior to the 1960's many landfills
were frequently operated'as open-burning
dumps. While this caused air pollution and
vector control problems at the time of
their operation, the end result was that
most of the material left in the landfill
was non-biodegradable. This meant that
there was much less ultimate settlement of
the landfill and much less or practically
no development of anaerobic gases after
the landfill was closed. The modern land-
fill does not permit Open burning; there-
fore, it provides much more food for
microorganisms. It is these microorga-
nisms which generate the gases, mainly
carbon dioxide and methane, which present
problems for growing vegetation.
When the refuse is first placed in
the landfill it is intermixed with oxygen.
Therefore, the initial decomposition takes
place aerobically, resulting mostly in the
generation of water vapor and carbon di-
oxide. However, this oxygen is soon con-
sumed, and since the refuse is deposited
with compaction and covered with soil,
there is minimal opportunity for new air
to move into the refuse. This results in
anaerobic degradation of the refuse,
whereby methane and carbon dioxide are
produced.
High concentrations of carbon dioxide
in the root zone of plants has been
reported to be directly toxic to the vege-
tation (1,2). Although methane has not
been reported to be toxic to the vegeta-
tion per se; it is possible that, combined
with the carbon dioxide it can remove
oxygen from the root zone of the vegeta-
tion by direct displacement and/or by
utilization of the oxygen by methane-con-
suming bacteria. The end result is a very
low or zero oxygen tension in the root
zone of the vegetation, which could be
toxic to the vegetation (3). In addition,
there are frequently minor fractions of a
number of other gases present in the land-
fill gases (k} including ammonia, hydrogen,
hydrogen sulfide, mercaptans, ethylene,
etc. One or more of these gases have been
known to exhibit direct toxicity to
218
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vegetation. .In any case, we associate
the presence of persistent high concentra-
tions of combustible gases in the soil
atmosphere with poor health and eventual
demise of vegetation.
In addition to causing vegetation
growth problems, methane is combustible.
This can result in fires and/or explosions
where the gas reaches its flammable limits
(5 to 15$ methane in air) in confined
spaces, such as a sump, a room, or a
building.
Many landfills are being built into
the ground to depths greater than 50 ft.
This extensive depth of refuse coupled
with the high compaction and daily cover
can result in high gas pressures building
up within the landfills, at times greater
than 5 pounds per square inch (5). These
gases travel out of the landfill via the
easiest route. This can result in the
landfill gases traveling beneath the
ground laterally from the landfill. Land
adjacent to former sand and gravel pits
is particularly receptive to this migra-
tion. The landfill gases may migrate to
areas where they can cause poor health
and/or death of vegetation. They can also
migrate into buildings where they may
cause fires and/or explosions. Landfills
in former sand and gravel pits are parti-
cularly noted for having problems with
the external migration of landfill genera-
ted gases into the surrounding soils.
This is in most cases due to the high
porosity of adjacent soils and their lack
of resistance to the movement of these
gases. We have also observed that when
the mixtures of adjacent soils are hori-
zontal layers of sand and gravel inter-
spersed with clay layers, the distance of
migration may be the greatest, because the
clay layers tend to prevent the vertical
movement and venting of the gases from
the soil. Freezing of the ground surface
and extensive rainy weather also seem to
contribute to the increased lateral
migration of these gases. Therefore,
vegetation growth problems are found not
only on former landfills, but frequently
in areas adjacent to landfills.
Field Measurements
To determine whether or not foreign
gases are present in the soil atmospheres,
it is necessary in most cases to first
make a hole in the ground. We use a
commercial bar hole maker to obtain a 3 ft.
deep, 1/2 in. diameter hole in the ground.
This commercial instrument incorporates a
steel hole-making rod and a driving weight
into one convenient unit. This same type
of unit is used by most gas utility
companies when searching for leaks from
their underground pipes. The handle of
this bar hole maker is electrically
insulated for safety to prevent a shock
should you come in contact with a live
underground electric wire.
The most convenient test to make in
checking for gases of anaerobic decomposi-
tion of organic matter is for combustible
gases with a combustible gas meter. A gas
sample is drawn from the bar hole through
an M.S.A. Explosimeter, which is one of
the types of instrument used by the gas
utility companies when looking for leaks
in their underground lines. The Wheat-
stone ' s bridge principle is used within
the Instrument for determining the concen-
tration of combustible gases. One leg of
the bridge consists of catalytic unit that
burns the combustible gases—changing its
resistance, thereby unbalancing the bridge
and giving a reading on the galvanometer.
The sample is withdrawn from the bar hole
by use of a 3 ft. long nonsparking probe.
If desired, a nonconductive probe may be
used. A rubber stopper is placed over
the upper end of the sampling probe to
help seal the bar hole from the ambient
air. However, the nature of the sampling
method frequently incorporates large
quantities in dilution air. These combus-
tible gas reading instruments indicate
percent of the lower explosive limit of
the gases for which the instrument is
calibrated. The lower explosive limit
for methane is a 5$ dilution in air.
However, it is possible to tell from the
response of the meter whether or not the
combustible gas concentration is between
the lower and the upper explosive limits
or above the upper explosive limit (15$
methane in air). By the use of a dilution
tube on the intake side of the meter, it
is possible to theoretically determine
the actual combustible gas concentration
up to 100$.
219
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The instruction manuals should, he
followed closely when using these meters
and the instruments should be maintained
and calibrated regularly. Calibration
equipment is available, and the instruc-
tion booklet will inform you as to the
frequency and extent of routine mainten-
ance.
Another type of combustible gas test-
ing meter, frequently used by the gas
companies, operates by determining the
thermal conductivity of the gas mixture.
The meters are calibrated for methane in
air. However, when measuring landfill
gases carbon dioxide is frequently a
major component of the mixture. Under
these conditions the thermal conductivity
meters wiH give inaccurate readings for
the methane concentration. Therefore, we
suggest that such meters not be used to
measure the concentration of methane in
landfill gas.
The carbon dioxide and oxygen concen-
trations of the ground gases obtained.
from the bar holes are analyzed by an
Orsat method, which is normally used to
measure the efficiency of fossil fuel-
fired furnaces. In our field test work,
we use the Bacharach Fyrite carbon dioxide
and oxygen indicators. In the carbon
dioxide indicator, the carbon dioxide is
absorbed in a potassium hydroxide solution.
In the oxygen indicator, an acidic ehrom-
ous chlorine solution is used. Carbon
dioxide indicators are available for
reading 0 to 20$ and 0 to 60% concentra-
tions. The oxygen indicators determine
0 to 21% concentrations.
Unpleasant ground gas odors are fre-
quently an indication of the presence of
the gases of anaerobic decomposition of
organic matter. These odors can be
checked for by withdrawing a soil sample
from the ground and smelling the sample.
If the unpleasant odors of anaerobic
decomposition are present, you will know
it without having to receive any instruc-
tions .
Soil temperatures are recorded in
degrees F by means of a thermometer with
a 3 ft. long stem. The sensitive section
of the stem is the bottom four inches.
Vegetation Death Problems in W.J.
Our first experiences with vegetation
death due to landfill gases were in N.J.,
and involved the lateral migration of the
gases from landfills to vegetation on
adjacent properties. In these cases, the
gases moved from the landfill laterally
into the undisturbed ground where they
occupied the root zones of the vegetation
leading to the eventual demise of the
vegetation. In some of the instances
corrective measures were implemented;
some of which were successful and some not.
In the early 70's a peach farmer in
Glassboro, New Jersey experienced the
death of acres of peach trees following
the filling of an adjacent 20 ft. deep
former sand and gravel pit with municipal
domestic refuse. The pit belonged to the
peach grower who had planned to have it
filled with the refuse, for which he was
paid by the municipality, .and then he
planned to extend his peach orchard over
the completed refuse landfill. However,
he found that the trees planted adjacent
to this landfill began to die a year or
two after the refuse had been placed
against the bank nearest his orchard.
Our examination showed that the soil in
areas where the trees had died contained
high concentrations of the gases of anaer-
obic decomposition. Landfill gas concen-
tration gradients indicated that the
gases flowed from the landfill. Although
the landfill was only 20 ft. deep, the
gases traveled out 70 or 80 ft, causing
death and injury to the peach trees.
This problem was repeated when young new
peach trees were planted in these gassed
soil areas.
The farmer no longer attempts to
plant trees in those areas which contain
the gases of anaerobic decomposition, but
no control measures have been taken to
prevent the lateral migration of these
gases. Time will eventually solve the
problem as the refuse material degrades
to where it no longer produce sufficient
anaerobic gases to cause problems. How-
ever, this might take scores of years.
The township of Cherry Hill, New
Jersey has experienced landfill gas migra-
tion problems since 1968 when a homeowner
noticed that his backyard vegetation was
dying. The backyard of this home and a
couple dozen others abut a former sand
and gravel pit which the municipality was
filling for eventual use as a park. Gases
were eventually detected up to about 90 ft.
220
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from the landfill, and in two of the
homes fires were caused "by these gases.
Problems of dead vegetation and the
entrance or potential entrance of the
combustible gases into the homes ultimate-
ly involved more than a dozen and a half
homeowners. These problems were taken
into court. After a week of testimony,
the case was settled out of court with
the municipality paying about $6o,000 to
the homeowners and installing a convec-
tive gas-venting system around the land-
fill. This system has worked in part;
however, there are still places where the
gases are bypassing the system and moving
into the backyards and perhaps even into
one or two of the homes adjacent to the
landfill. Fortunately, no fires have
been reported within the homes since the
installation of these venting systems.
The township is still attempting to
transform the former landfill into a
park. Part of this effort has involved
the planting of scores of trees. However,
most of these trees have died during the
past year and a half. Our exam:? nations
indicate that, although landfill gas is
probably the cause of death of a number
of these trees, many others appear to
have died because of poor transplanting
practices. In a number of cases the roots
were pruned too extensively during trans-
planting. In other cases there seems to
have been a lack of adequate watering
following transplanting.
For a number of years we have been
working with a farmer in Cinnaminson,
New Jersey who has experienced the death
of tomatoes, corn, sweet potatoes, and
rye cover crop because of migrating land-
fill gases. Over a period of about 5
years the distance of lateral migration
of these gases gradually increased to
more than 800 ft. from the nearest edge
of the landfill. These gases would
appear in oval patches in the farm fields
where they caused the death of vegetation.
A number of systems have been tried
by the landfill operator to prevent this
migration. He first installed a 15 ft.
deep trench filled with stone as a vent-
ing mechanism. Next, at the edge of the
landfill, he installed a series of
vertical venting pipes to depths of 30 to
ho feet for convective venting of the
gases. However, the bottom of the land-
fill was reported to be 50 to 60 ft.
below the farm field; therefore, these
convective vents did not stop the continu-
ous lateral extension of the landfill
gases. MText, a number of soil logs were
made to determine the actual depth of the
landfill gases and the water table plus
the character of the subsoils. These
tests revealed that the soil consisted of
a series of horizontal sand and gravel
layers interspersed with horizontal clay
beds. Apparently the clay beds kept the
gases down and caused them to migrate
laterally great distances. These soil
logs also revealed that combustible gases
were found at the 60 ft. depth, beneath a
deep clay layer just above the water table.
It was probably this sand strata which
conducted the gases the furthest distance.
During the summer of 19?6 the land-
fill company installed a series of deep
vertical wells to evacuate the landfill
gas from this deep stratum by an induced
draft pump. Tests we conducted in the
fall of 1976 gave a preliminary indication
that this system has been successful. For
the first time in a half dozen years we
could find practically no combustible gas
in the farm fields. A cover crop of rye
has been planted, and there was no sign
that landfill gases had caused damage to
the crop last fall. Apparently this
positive extraction system has pulled the
gas out of the farm field. We hope that it
will continue to operate successfully to
prevent the gases from re-entering the
farm field. We do not know how long it
will be necessary to continue to operate
this protective system which requires an
electrical supply and regular maintenance.
Prior to the successful operation of
the positive extraction system, there was
also a problem with the potential for the
gas to enter one of the farm houses. Com-
bustible gases were detected right next
to the exterior of the house foundation,
and it was necessary to install an automa-
tic monitoring and alarm system within the
home to prevent a tragedy. However, fall
1976 tests indicated that these gases are
no longer a hazard to the home.
Mail Survey of U.S. Landfill Vegetation
Problems
In May 1975 our Rutgers group was
awarded a USEPA grant for a 2 year study
of problems associated with vegetating
landfill sites. The first phase of the
221
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research entailed a mail survey to deter-
mine the national scope of landfill
vegetation problems. Approximately 1000
questionnaires were mailed out to indivi-
duals or agencies that we felt could
furnish such information. We received
replies from all 50 states plus Washing-
ton, B.C. and Puerto Rico describing a
total of kfl sites. No problems were
reported by 356 sites, 31 reported vege-
tation growth problems adjacent to land-
fills , and 120 indicate problems -with
growing vegetation on landfills. There-
fore, about 30$ of the reported sites
said they had some sort of vegetation
growth problem. A number of sites were
reported more than once, which accounts
for the lack of agreement between the
total and component numbers.
On-site Visits to Former Landfills
Throughout U.S.
On the basis of the returns from the
mail survey representative sites in eight
major meteorological areas were selected
for field observations. Various members
of our research team have made field trips
to most of these locations.
Field observations included the eval-
uation of plant species on and/or adjacent
to former landfills and the selection of
healthy and poorly growing specimens of a
given species for an in-depth examination.
Analyses for combustible gas, carbon di-
oxide, and oxygen were made of the soil
atmospheres in the root areas of many
trees and other vegetation exhibiting
poor and good growth. The temperature of
the soil at these locations was also
measured, and soil samples were returned
to the Rutgers Soils Laboratory for
analysis.
Almost invariably, a high correlation
resulted between high concentrations of
combustible gas and/or carbon dioxide
(C02) and/or low oxygen (0.) and a poor
growth status for the tree or shrub.
Examples of this relationship are pre-
sented for the Northeastern U.S. region
(cool summers and cold winters) in Table
1. At a Battle Creek, Michigan landfill
a red pine exhibiting only a needle tip
necrosis contained no combustible gas,
6.5% C02, and 19.5% oxygen in its root
atmosphere at a 1-foot depth. The root
zone of a dead red pine, on the other
hand, contained £5% combustible gas, 21%
COg, and only 12$ oxygen. Similarly, a
healthy, 20-ft. tall willows on an Auburn,
N.Y. landfill contained no combustible gas
or C0g and 20% oxygen at the 1-ft. depth;
whereas beneath a nearby dead willow
there was combustible gas and decreased
oxygen concentration.
Results for the Southwestern California
region (hot summers, warm winters, with a
concentration of the year's modest preci-
pitation in the winter) are represented
by data from the South Coast Botanic
Garden in Los Angeles which has been
built on a former landfill (Table 2).Here,
a Cytisis raeemosis in good condition
contained no combustible gas or CO .at
the 1 ft, depth, whereas beneath a dead
Cytisis combustible gas had risen to 22&,
CCU to 15$, and oxygen content had
decreased to 11.5$. Somewhat similar
relationships are shown for Melaleuca,
Aleppo pine, and Eucalyptus.
Excellent correlations were foixad in
coastal northwest area (temperate oceanic
climate) between high concentrations of
combustible gases in the soil atmosphere
and dead vegetation or no growth (Table 3).
The two sites in Seattle, Washington are
over former landfills while the Day Island
site is a woodlot adjacent to a former
landfill. Over the landfills it was the
barren spots which had high concentrations
of combustible gas near their surface
while none or only a trace of combustible
gas could be found in the good growth
vegetation areas.
Other examples of good correlations
between high concentrations of landfill
gases and poor or dead vegetation are
given in Table k. Here representative
comparisons are cited from Alabama
(subtropical humid climate), Montana
(semi-arid cold winter-steppe climate),
and Long Island, New York (temperate
continental-warm summer climate) areas.
Sites from, on and off the former landfills
are presented, and each indicates that
poor vegetation growth is associated with
the presence of landfill gases in the
soil atmosphere. However, since these
field measurements are made only at one
moment in time we do not always find a
positive correlation. We have found that
landfill gases do come and go from an
222
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area; therefore, it is possible for them
to be present, do their damage and then
leave. It also takes some time for the
adverse effect of their presence to
manifest itself in plant symptoms, so it
would be possible to find the gases to be
present for a short time at the base of
an apparently healthy plant.
Table 5 records the "classical" field
observations we might expect to find
associated with the lateral migration of
landfill gases and its associated
vegetation death. The Holtsville Land-
fill is in a former sand pit, and the
landfill gases have migrated through the
soil into an adjacent woodland. Where
the landfill gases axe present in the soil
the trees have died, and we find the soil
in a septic condition. The temperatures
of the soil containing the landfill gases
are also somewhat higher than the soils
without the landfill gas. Death of
vegetation and associated septic soil
conditions are frequently found adjacent
to landfills placed in former sand and
gravel mining pits.
Soil .Temperature Abnormalities
Although high temperatures are not
normally associated with anaerobic decom-
position we frequently, but not always,
find higher soil temperatures associated
with the presence of landfill gases.
Occasionally, we find very high soil
temperatures associated with landfill
gases. In January 19?6 we experienced
our first such high readings at the
South Coast Botanic Garden in Los Angeles.
Here we recorded a soil temperature of
1*K)0F. at a 1*2" depth. This was in an
area where the cover soil had cracked and
landfill gases were flowing from the crack.
All vegetation adjacent to the crack was
dead. Armand Sarinana, Superintendent of
the South Coast Botanic Garden, attributes
many of his poor vegetation growth ^g\
problems to extreme soil temperatures' .
Sarinana reports that areas of extreme
soil temperatures, 120° to l6o° F, are
localized in the garden while more
general areas of lower temperature, 70°
to 90° F, are common throughout the
garden. This is 15° to 20° -warmer than
the average home garden soil temperature
in the vicinity of this facility averages
between 55° and 70° F. Sarinana writes
that once the soil temperatures are
dropped vegetation can be re-established.
An approximate 8° F differential in
temperature was found between no gas and
landfill gassed soils adjacent to the '
Huntington Landfill (Figure 1). The
higher temperatures were found in the
gassed soils. A similar situation existed
on and adjacent to the Day Island Land-
fill in Oregon where the higher tempera-
tures were found in the soils containing
landfill gases (Figure 2). Here the
highest and lowest temperatures were
found off the landfill where the gassed
soils were more than 30° F. warmer than
the ungassed soils. At Day Island, the
soil temperature decreased with increas-
ing depth while the opposite was true at
Huntington.
Many reasons have been attributed to
the cause of these occasional high soil
temperatures including: composting,
chemical reactions, and underground fires.
The highest soil temperature we have
recorded to date associated with a land-
fill was 15k° F. at the 3 ft. depth in
uncovered refuse at the Fountain Avenue
Landfill in New York City on November 23,
1976. The area with this high tempera-
ture was "steaming" as the moisture in
the gases leaving the landfill condensed.
Soil Quality Data - Gassed vs. Non-gassed
Soils
Top and subsoil samples from each of
six meteorological regions were analyzed
for content of major and trace nutrients,
pH, moisture, organic matter, conductivity
and for soil texture. Table 6 contains a
summary of the data expressed as percent
change (+ or -) in each constituent as
the soil proceeded from a no landfill gas
to a high landfill gas condition.
There was very little difference in
content of the major nutrient elements
(magnesium, phosphorus, potassium, and
calcium) between gassed and ungassed soil.
Since these elements are normally present
in soil in hundreds or thousands of
pounds per acre, a small percentage
fluctuation in content would have a
negligible effect on plant growth.
Nitrogen compounds (NO--N and NH^-N)
and trace elements (iron, manganese, zinc,
copper, and boron) which are normally
present in much lesser quantity, increased
many fold in soils with high concentrations
223
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of landfill gas in their atmospheres. In
particular, the ratio of iron to manganese,
a critical value in soil fertility, was
frequently above the recommended, range for
adequate plant growth.
Conductivity, -which is a measure of
total ion activity5 was, understandably,
increased as well.
Soil pH was either increased or
decreased depending on the original condi-
tion of the soil; alkaline soils such as
those in Utah and Idaho decreasing, while
the more acid soils of the Northeast
increased in pH value.
The reason for the observed increases
in content of nitrogen compounds and
trace elements in gassed soils undoubtedly
lies in the lew redox potential of these
soils as has been documented for similar
responses of soil to flooding conditions.
When oxygen disappears from the soil,
requirements of anaerobic soil micro-
organisms for a source of oxygen results
in the reduction of several oxidized
compounds namely nitrate, nitrite, and
the higher oxides of manganese, and iron.
These reduced forms are generally more
soluble and hence are made available to
plants. Availability of other trace
metals occurs as they are displaced by
ferrous ions from the exhange complex to
the soil solution.
The trend to neutrality in pH is
caused by the buffering effect of organic
acids released by the microbial breakdown
of organic matter.
The consequences of these soil changes
in landfills have yet to be evaluated.
However, it is not improbable that trace
element toxicities may also play a role
in the detrimental effects of landfill
conditions on plant growth.
Field Evaluation of Possible Anaerobic
Soil Gas Vegetation Problems
Certain basic information is valuable
for use in the field to determine whether
or not the potential exists for a vegeta-
tion viability problem caused by gases
from buried organic refuse. It is always
advisable to ask about the property to
determine whether or not it had ever been
a refuse landfill or if there had been
such an operation adjacent to the property
under consideration. However, information
obtained by word of mouth may not always
be reliable. Therefore, the following
criteria are suggested for on-site evalua-
tion of the potential for a landfill
vegetation growth problem:
1. Is there unhealthy or dead vegeta-
tion in the vicinity?
Obviously, many things could cause
poor quality or dead vegetation,
but there is always the possibility
that it might have been caused by
landfill gases.
2. Do you notice any unpleasant odors
in the vicinity?
Again, unpleasant odors come from
many sources. Those odors from.
landfills or soils turned septic
by landfill gases are generally
of a putrid nature. In moving
over a former landfill you can
occasionally detect them in the
air as they are discharged through
surface cracks, or as you work
with the soil you may notice the
septic odor.
3. Examine the soil. It is easy to
draw a soil sample and examine it
in the field.
Table 7 inay be used as a general guide
to soil aerobic/anaerobic conditions.
Under certain circumstances there will be
exceptions to these general guidelines.
However, those who work with soils know
the typical characteristics of a healthy
soil and will easily recognize the quali-
ties associated with an anaerobic soil.
Soil temperature differences are sometimes
extreme and sometimes very modest. We
have recorded temperature differentials
as high as 30° F. between, a normal
healthy aerobic soil and a nearby
anaerobic soil. However, in most cases
the difference is very small, and
occasionally we find the anaerobic soil
at a lower temperature than the aerobic.
The farmer in Cinnaminson, N.J. felt
that something was wrong with his soil for
two reasons. One was the septic odor
released when he plowed it, and secondly,
the unnatural way in which the furrow lay
during plowing. Instead of the soil
falling in an even mound, it fell in
224
-------
clumps; the soil did not "break apart
easily as is natural for this soil.
The higher moisture content of
anaerobic soils is possibly due to the
condensation of the water vapor generated
by the decomposition of the organic
matter within the landfill. The darker
color of these anaerobic soils is probably
due to their septic nature.
Of course, one can always look for
landfill gases in the soil by means of the
instrumentation previously described.
Finally, the area should be observed
for indications of any unusual settlement.
Landfills left unused for a while develop
uneven settlement. This plus a number of
surface cracks in the soil are sometimes
indicators that there might possibly have
been organic refuse buried here in the
past.
Control Measures to Reduce Vegetation
Losses
Measures for control of landfill vege-
tation growth problems involve: construc-
tion of the landfill; vegetation cultural
methods including proper fertilization,
soil amendments, and irrigation; removing
the landfill gas from the vegetation area;
the use of tolerant plant species; and
suitable planting techniques. These
control techniques are summarized in
Table 8.
Research is now being conducted at
Rutgers in order to investigate some of
these factors. One project involves the
screening of 19 woody species for toler-
ance to landfill growth conditions.
The experimental plot is located on a
former landfill in New Brunswick, New
Jersey. A nearby natural woodland site
was cleared as a control area. The 19
species were planted in replicates of 10
and observations are being made for tree
height and girth, shoot elongation,
fruiting, and the presence of heart rot.
The rhizosphere of each tree is also being
analyzed for gas composition, including
combustible gas, carbon dioxide and
oxygen, and for soil temperature. Soil
samples are also taken for analyses of
the chemical constituents of the soil.
Besides the screening program, five
planting techniques have been employed,
including two mounds and three trenches
with no gas protection or underlain either
by 1 ft. of clay or by a plastic sheet over
a gravel base, with and without vertical
venting pipes.
A second experiment is being carried
out in the greenhouse, and entails an
investigation of the effect of varied
concentration ratios of methane; carbon
dioxide; and oxygen circulated through the
root zones of seedlings growing in sand/
solution culture.
Preliminary results appear to indicate
that tomato plants whose roots were exposed
to a gas mixture containing methane, carbon
dioxide and oxygen roughly in the propor-
tions in which they exist in anaerobically
respiring landfills, suffered growth
alterations which were more marked than
those sustained by similar plants which
were merely deprived of a normal oxygen
supply.
Meaningful results of the field and
greenhouse experiments will not be
immediately forthcoming. However, when the
data have a.ll been collected it is hoped
that we will have a better understanding
of landfill vegetation problems and that
we will be able to make recommendations of
species and planting techniques for greater
success in the vegetation of former land-
fill sites.
Conclusion
The field examinations we have con-
ducted of landfill vegetation throughout
the United States indicate that poor
growth or death of the vegetation is
directly associated with the presence of
landfill gases in the soil atmosphere. It
appears that the vegetation dies as the
soils become anaerobic from the physical
displacement and/or biological consumption
of the soil oxygen.
To obtain a successful growth of
vegetation above or adjacent to former
refuse landfills the root zone of the
vegetation must be protected from the gases
of anaerobic decomposition of the organic
matter in the landfills.
225
-------
REFERENCES
1. Leonard and Pinkard, "Effects of
Various 0- and CO. Levels on Cotton
Root Development," Plant Physiology
V. 21, p. 18-36, 1955;
2. Noyes, H.A., "The Effect on Plant
Growth of Saturating the Soil with
CO," Science V.*K), p. 792.
3. Flower, F., Leone, I., Arthur, J., and
Oilman, B., "Effect of Low Oxygen on
Plant Growth," Quarterly Report, EPA
Grant Project #R-803762-01, January
1976.
k. Farquhar, G. J-. and Roves, F.A., "Gas
Production During Refuse Decomposition."
5. Nielsen, Douglas C., Principal Engineer
Public Service Electric and Gas Co.,
Newark, N. J. Personal Communication
2/25/77.
6. Sarinana, Armand, "A Landfill Botanic
Garden," Lasca Leaves, Vol. XXV, #3,
9/75.
226
-------
TABLE 1
FIELD DATA N.E. (1975)
0 at 1' Depth
Site
Auburn, N.Y.
Battle Creek, Mich.
Guilderland, N.Y.
Species
Willows
Willows
Red Pine
Red Pine
Poplars
All Veg.
Condition
20' Tall
Dead
Tip Necrosis
Dead
4 '-8' Tall
Dead
Comb . Gas
Approx.
0
15>5
0
25
10
>50
co2
Volume '
0
0
6.5
21
15
36
°2
I
20
18.5
19.5
12
19
2
-------
KJ
IS3
00
Table 2
Los Angeles Area,
'Field Data Cal. (1975)
Volume % at 1' Depth
Q J.UC
S. C. Bot. G.
S. G. County Pfc.
S. C. County Pk.
M. G. Golf Course
toiss. Canyon
*3pei..i.ec>
Cytisis Racemosis
Cytisis Racemosis
Melaleuca
Melaleuca
Aleppo Pine
Aleppo Pine
A. Pine & Eucalyptus
A. Pine & Eucalyptus
A. Pine
A. Pine
A, Pine
t_>UUU JLUJ.UI.1
Healthy
Dead
Healthy 12'
Dead
Green -65"
Chlorotlc
Good
Poor-
Healthy
Yellow Color
Yellow Tips
t^UUiU •
0
22
4
>50
<1
>50
0
>50
0
0
<1
v>u«
0
15
5
43
0.5
25
0
5
0
1
6
"2
19.5
11.5
7
3.5
17
11
20
9.5
21
19.5
20
-------
Table 3
N.W. U.S. Area
Field Data (1976)
Site
Species
Condition
Approx. % Combustible Gas
at Various Soil Depths
ro
ro
f>
University of Washington
Seattle, Wash.
(On Former Landfill)
11 tl If
Genesee St. Park Devel.
Seattle, Wash.
(On Former Landfill)
II 1! II
Day Island Landfill
Lane County, Oregon
(Adjacent to Landfill)
2' Tall Alfalfa
Clover, Rye, and
Vetch
None
Grass and Weeds
None
White Ash and
Broad Leaf Maple
Healthy
Barren Ground
Healthy
Barren Ground
Healthy
Dead
1' 2' 3'
00 0
15>5 15>5 20
00 —
>15 >15
0 — 0
15>5 — >50
-------
TABLE 4
FIELD DATA (1976)
co
o
Site
Species
Condition
Approx. % Combustible Gas
at Various Soil Depths
Old Dothan City Landfill
Ashf or , Alabama
(Adjacent to Landfill)
H ti M
Great Falls San. Landfill
Great Falls, Montana
(on Former Landfill)
II IT II
Kings Park, San. Landfill
Smithtown, L.I., N.Y.
(Adjacent to Landfill)
ii H M
M It It
II II II
I1 2' 3'
Loblolly Pine Healthy 000
(25* tall)
Loblolly Pine Dead 5 >50 >50
(20' tall)
Wheat Good Growth 0 T 20
Wheat Very Poor 28 >50
White Oak Living T
(30* tall)
White Oak Dead >50
(30' tall)
Hemlock Living 0
( 7' tall)
Hemlock Dead 8
( 6' tall)
-------
TABLE 5
SOIL AND VEGETATION CONDITIONS ADJACENT TO
HOLTSVILLE LANDFILL
BROOKHAVEN TOWNSHIP, L.I., N.Y.
10/14/76
Approx % Combustible Gas
at Various Soil Depths
I1 2' 3'
30 >50 >50
Soil
Conditions Species Conditions
Septic Odor Red Oaks Dead
Dark Color
Damp
Ground
Temps (°F)
70 - 80
Normal Soil Odor
White Oaks
Live
62 - 67
-------
TABLE 6
PERCENT ($) CHANGE IN CONTENT OF CONSTITUENTS AS SOIL PROCEEDED FROM NON-LANDFILL GAS
TO HIGH-LANDFILL GAS CONCENTRATIONS
Meteorological Region
Soil Constituent
Lb/Acre
Mg
P
K
Ca
NO -N
NH^-N
£
H20
Org. Matter
Sand
Silt
Clay
£pm
Fe
Mn
Cu
Zn
B
Fe/Mn
Cond. (tfciohs)
pH
Dca
N.J.
- 5.6
- 11.1
+ 27.3
- 17-1
+ 170.2
+ 93.8
+ 37.8
- 50.0
- 4.4
+ 100.0
+ 11.1
+ 11*6.8
+ 65.1*
+ 10.8
- 6.7
+ 2.1*
+ 1*9.6
+ 210.0
- 5.6
Deb
N.E.
- 6.2
- 13.6
+ 33-9
+ 19.5
+ 2.2
+ 222.0
+ 6.8
- 35.2
+ 3.8
- 13.7
- 9.3
+15,500
+ 125.0
+ 200.0
+ 785.0
_
+7150.0
+ 66.7
+ 3.5
Do
N.W.
1 0
+ 13-9
- 26.0
+ 3.8
- 7.6
+800.0
- 12,7
- 9-3
- 12.0
+ 8.8
+ 10.5
+ 39.6
+ 25.8
+ 38.3
+ 63.5
+ 67.5
+ 10.8
+117.0
+ 7.8
Cf
Ala.
- 9.2
- 1*.8
-20.4 .
+50.9
-17.5
-47.1
- 7.5
+ 9.1*
+11*. I*
-31.1
-26.7
+28.3
+19.0
+70.5
+1+10.0
- 3.7
+ 7.8
+210.0
+ 7.2
Bs
Utah
to
+50.0
to
+ 8.3
-15.0
-58.3
+11*. 3
-22.1
+10.0
- 5-9
-23.0
-
-
-
+ 2.6
-
to
- 1.2
H
Idaho
+ 1.6
+37.5
+ 9.0
-13.4
+23.9
-52.6
+ 5.3
+79-1
+12.6
-17.3
- 7.5
+28.0
+286.0
- 28.0
+370.0
+ 3.4
- 68.6
+100.0
- 2.4
Mean
- 3.2
+ 11.8
+ i*.o
+ 8.7
+ 26.0
+159-6
+ 7.3
- 4.7
+ 4.1
- 6.8
- 7.5
+3,148
+104. 2
+ 58.3
+324.4
+ 14.4
+1430.0
+ 117-3
+ 1.6
232
-------
TABLE 7
GUIDE FOR EVALUATION OF LANDFILL SOIL GAS PROBLEM
Characteristic
Odor
Color
Moisture Content
Frability
Temperature
Combustible Gas
Oxygen
Carbon Dioxide
Anaerobic Soil
Septic
Darker
Higher
Poor
Higher
Higher
Lower
Higher
Aerobic Healthy Soil
Pleasant
Lighter
Lower
Good
Lower
Very Low or Zero
Higher
Lower
233
-------
TABLE 8
CONTROL TECHNIQUES TO REDUCE VEGETATION LOSS
1. Suitable Species -
Shallow Rooted, Adapted to Anaerobic Conditions
2. Cultural Methods -
Adequate Lime, Fertilizer, Top Soil for Cover, Irrigation
3. Soil Amendments -
Shredded Refuse, Mulch, Sewage Sludge
4. Landfill Construction -
Proper Grading, Compaction, Adequate Depth and Quality of
Cover Soil and Top Soil
5. Planting Techniques -
Vented or Lined Trenches, Mounds, or Gas Barriers
6. Gas Removal by Induced Draft Evacuation
234
-------
80
75
70
UJ
cc
IT
UJ
Q.
z
UJ
O
U)
60
55
50
O
O
O
ox
XX
SOIL CONTAMINATED WITH HIGH
C02 AND COMBUSTIBLE GAS
SOIL NOT CONTAMINATED WITH
MEASURABLE CO? OR COMBUSTIBLE GAS
i *t i
10 20 30
SOIL DEPTH IN INCHES
40
Figure 1
SOIL TEMPERATURES, IN THE.VICINITY OF HUNTINGTON LANDFILL, HUNTINGTON, L, I., N.Y,
10/15/76
235
-------
100,
90
80
LJ
DC
oc
ui
0.
70
60
O OFF LANDFILL AND GAS
0 ON LANDFILL AND GAS
X ON LANDFILL AND NO GAS
+ OFF LANDFILL AND NO GAS
o
o
50
10 20 30
DEPTH IN INCHES
40
FIGURE 2
SOIL TEMPERATURES, DAY ISLAND LANDFILL
June 24, 1976
236
-------
EFFECTS ON SOILS AND PLANTS FROM APPLICATIONS OF COMPOSTED
MUNICIPAL SOLID WASTE - A SUMMARY OF SELECTED RESEARCH PROJECTS
Carlton C. Wiles
U.S. Environmental Protection Agency
Municipal Environmental Research Laboratory
26 West St. Clair Street
Cincinnati, Ohio 45268
ABSTRACT
This paper presents a summary of results from research projects conducted to help
determine the effects on selected soils and plants from applications of composted munici-
pal wastes. The studies included investigations in greenhouses, field investigations,
and limited demonstrations conducted from 1969 through 1975. Positive and negative
responses to the waste applications were observed which related to increased and decreased
crop yields, soil improvements, and increases in some heavy metals in plant tissue.
INTRODUCTION
Composting has had a less than satis-
factory history in the United States. Al-
though technically feasible, poor market
and economic factors have resulted in the
failure of composting to be widely prac-
ticed as a solid waste management process.
Most composting studies now being conduct-
ed are aimed at providing an acceptable
disposal option for the high amounts of
sewage sludge requiring disposal. In ear-
lier studies, EPA evaluated composting as
a method for managing United States muni-
cipal solid waste, including sewage
sludge. Among these evaluations were the
research and demonstration at Johnson City,
Tennessee (open windrow) and Gainesville,
Florida (mechanical high rate digestion).
Although these composting projects
included provisions to evaluate the utili-
zation of the composted product, major
investigations concerned the evaluation of
the process, equipment performance, and
economics. Additionally, because of
changes in the overall solid waste R&D
mission and redirection of available re-
sources to higher priority needs, the
projects were terminated before meaningful
marketing studies and utilization evalua-
tions could be fully implemented. There
were, however, some efforts to demonstrate
the benefits of using the compost for re-
claiming poor soils and increasing crop
yields. Dr. Hortenstein at the University
of Florida utilized material produced at
the Gainesville plant. Results of these
studies have been reported in a number
of publications.* Compost utilization
efforts at Johnson City, Tennessee,
initially involved applications of com-
post to strip mined areas for'reclamation,
and limited applications to crop producing
lands. Responses were measured by record-
ing visual observations and by crop yield
information. Prior to the termination of
the Johnson City project, plans were
formulated to increase the utilization
studies and to include greenhouse as well
as field evaluations of the effects of
*EPA Research Grant No. EC-00250
237
-------
the composted wastes when applied on
selected soils and plants. One of the
driving factors to implement these studies
was a concern about potentially toxic mate-
rials such as heavy metals which might be
carried in the compost and transmitted to
soils and further to ground water and food
crops. A number of projects were initiated
prior to the plant's closing and provisions
were made to permit selected studies to
continue at reduced levels after the
Johnson City composting plant closed.
Those studies continued included projects
in the vicinity of Johnson City, Tennessee,
at the National Fertilizer Research Center
at Muscle Shoals, Alabama, and at other
miscellaneous locations.
The purpose of this paper is to describe
selected portions of the Johnson City com-
post utilization research and demonstrations
and to summarize major results. The studies
were conducted during the period 1968
through 1975. Details are available.*
INVESTIGATIONS
For purposes of organization, the in-
vestigations are divided into three cate-
gories, i.e., Field Studies, Green House
Studies, and Others.Field studies involved
application of varying amounts of composted
municipal solid waste-sludge mixtures, sew-
age sludge and chemicals to selected crops
under field conditions. Greenhouse potting
experiments were conducted under more con-
trolled conditions and in some cases under
accelerated time schedules. The other cate-
gory includes the corn experiments at the
Johnson City location, demonstrations, and
other miscellaneous projects which primarily
involved land reclamation.
Field Studies
Field studies at Muscle Shoals, Ala-
bama, included evaluation of the responses
of forage sorghum and common bermuda grass
to Municipal Solid Waste (MSW) compost;
responses of sweet corn and string beans to
zinc and other heavy metals contained in
municipal wastes; measurements of heavy
metal content of several vegetable species
grown in soil amended with sewage sludge,
*A Bibliography of information avail-
able from this work is included.
and others.
Sorghum and Bermuda Grass
These experiments were among the first
to be implemented and were designed primar-
ily to determine the crop growth responses
to compost and to determine compost appli-
cation rates which would be detrimental.
In the first experiment, forage sorghum was
the test crop. Thirteen treatments compar-
ing combinations of fall and spring appli-
cations with and without supplemental N
fertilizers were compared. Compost at total
application rates ranging from 23 to 326
metric tons/hectare (ha) (dry-weight basis)
were applied over a 2-year period. All
plots were fertilized with P and K at rates
determined necessary from soil analysis
according to acceptable practice. All
treatments were replicated four times.
The sorghum forage was removed in two
cuttings each year from 1969 through 1971;
but was cut only once in subsequent years.
In addition to measuring crop production,
forage samples were analyzed for several
macro- and micronutrients.
In the 1968 experiments involving
common bermuda grass, compost was applied as
a top dressing at rates of 0, 9, 18, and 27
metric tons/ha. One year later, compost
was again applied, but at triple the 1968
application rates. Nitrogen was applied to
these plots after the second compost appli-
cations. The grass was harvested four
times.
Summary Results on Sorghum and Bermuda Grass
Higher yields were observed with annual
compost applications of rates up to 143 and
80 metric tons/hectare (ha) on sorghum and
bermuda grass, respectively. However, the
highest yields of either crop attained with
compost were surpassed by application of
fertilizer nitrogen (N) at the rate of 180
Kg/ha with adequate phosphorus (P) and
potassium (K), In addition to increasing
the fertility of the soil, compost appli-
cations increased moisture-holding capacity
and decreased the bulk density and compres-
sion strength of the soil. These effects
were observed for three years. Although
the results showed that relatively large
tonnages of compost can be applied to grass
or crop land, the measured economic return
in terms of increased crop yields versus
application expenses was minimal. Of
238
-------
further concern was the observed elevation
of Zn and to a lesser extent other heavy
metals. These were largely derived from
the sewage sludge in the composted refuse.
Additional details of these experimental
results are provided in Tables 1 through
5 and in Figure 1.
Availability of Zn in Compost and Sewage
Sludge
The second series of investigations
were initiated to compare the availability
to corn and string beans of Zn in compost
and sewage sludge with comparable rates of
ZnS04- These studies were prompted by the
elevated levels of Zn found in the forage
sorghum grown on compost treated soils.
Appropriate species of sweet corn and
string beans were selected as the test
crop because of their contrasting response
to high levels of available Zn. Soil
treatments consisted of three rates each
of dry garbage compost (56, 112, and 224
metric tons/ha), dry sewage sludge (50,
100, and 200 metric tons/ha), and ZnS04
all incorporated into the soil to provide
the equivalent of 90, 180, and 360 Kg of
Zn/ha. Treatments were replicated 4 times.
The crop area was irrigated as required to
assure that moisture stress would not limit
plant growth.
Sweet corn was planted so that there
were 4 rows in each test plot and later
thinned to a population of 50,000 plants/ha.
The corn was harvested in the milk stage.
String beans including vines were harvested
from two center rows of each string bean
plot. Soil borings were also taken from
all plots shortly after pi anting.corn each
year. These were analysed for Zn, Cu, Pb,
and Ni by atomic absorption spectroscopy
and Cd and Cr using a flame!ess atomizer
accessory. At harvest the two center rows
of each plot were cut, weighed, and total
dry matter production and yield of the
edible portion were measured. Plant mate-
rial samples were analyzed for Zn, Cu, Cd,
Cr, Pb, and Ni.
Summary of Results from Zn Availability
Experiments
The experiments were initiated in the
fall of 1971 and continued until 1975. The
overall results indicated that when ZnS04
and compost or sewage sludge were applied
at rates resulting in comparable applica-
O&KM. Mums or tXfftm vat (i. oar tfitw «*m).
f.ll IKk
ip»1"B 1H9
usu i. OMMSI tntm o« temita msctmtltoi » s
iuu j. covosi tmai w swt OCMC* auucmtiua or »u
igu im iw i«J
t.J !.« i.t i.t
f.f JW 10$
iw) »e
me M»
U41 *1W
«o <;**
tuu 4. awui [mm « sa« Mrsicm. otuucmnucs or sou
I«Ul
CMCOtt
•WHuttM
0
«
UJ
M4
loll
MUtBTt,
"l»0 ' IffT
1I.< 10,4
U.i 10.]
11.) 10.1
-rSJ1*3,*-
(,«*' l.»ft.i,
KM* l.4i
Km i!i)
UMMOM4 cewr«|ttO« ttr**!^, ^/c^
is™ im
I,l» t,i ^.v,
l.tt I.I
I.tk I.I
l.k t.I
TABLE 5. COMMON BERHUBA CRASS VIELB, AS AFFECTED BV COHPOST AND H
Conpost rate
metric tons/ha
1969 !970
0
0
9
9
18
IB
27
27
0
0
27
27
54
54
81
81
M rate, kg/ha
0
180
0
180
0
180
0
180
Dry forage yield
metric tons/ha*
1969
6.5C
)),4s
7.4bc
11. Za
7.6bc
12.5a
7.8b
11. 9a
1970
2.74
5.66
4.0c
6. Sab
6.3c
7.?a
4.7c
13.4!
Avg.
4. Sit
S.Sb
S.6c
8.7b
5.8C
9.9a
6.3c
9.Jat
•Values followed by the same letter are not significantly different
according to Duncan's HuitfpU Range Test (51).
239
-------
o
JL
22
I 18
d
O
at
O 10
u.
tt
Q
-i 6
Z
< 2
T T
T
COMPOST PLUS
90 kg N/ha
COMPOST PLUS
180 kg N/ha
COMPOST PLUS 180 kg N/ha
COMPOST PLUS
90 kg N/ha
0—0—0 1970
1969
1969
1970
14 28
9 18
46
36
82
91
72
163
TOTAL 23 46
COMPOST APPLICATION RATE, metric fons/ha
183
143
326
Figure 1. Effects of Compost Application on Forage Sorghum Yield.
240
-------
tions of Zn, availability of Zn to both
the sweet corn and the string beans was
considerably greater from ZnS04 over the
4-year period. In general the string beans
were less tolerant of high Zn treatments
even when applied as sewage sludge. Of the
other heavy metals monitored in these crops,
only Cd levels exceeded check values in
the plant leaves. The edible plant parts
were relatively unaffected.
Bean pods, however, did accumulate Ni
from sewage sludge, at levels two to four
times those from nontreated plots. Although
there was no indication that the elevated
levels of Cd or Ni were phytotoxic, the
consequence of animal or human consumption
was not determined. Tables 6 through 11
are examples of results available from
these experiments.
Heavy Metals in Several Species of Vege-
tables Grown in Soil Amended with Sewage
Sludge
Additional experiments were started to
compare responses of several other vege-
tables to heavy metals contained in two
different sewage sludges. These experiments
were initiated because the earlier studies
indicated that corn and beans differ in
capacity to accumulate Zn and other heavy
metals from soils amended with municipal
wastes.
These experiments were conducted in a
manner similar to those already described.
Anaerobically digested sludges from two
different sources (Table 12) were applied at
rates of 112 metric tons/ha (dry) in the
fall of 1973. Seeds of all vegetables
(Tables 13 and 14) were sown except peppers,
tomatoes, and lettuce, which were trans-
planted. Adequate soil moisture was main-
tained as required. Vegetables were har-
vested from triplicate plots as they matur-
ed and total yields were measured. Samples
of leaves and edible parts, in addition to
soil samples were taken.
Results
Increased yields of tomatoes and
squash were measured in response to appli-
cations of both the sludges; other species
were unaffected. Leafy vegetables, such as
lettuce and spinach, accumulated Zn, Cd,
and Cu. Radish and turnip roots contained
somewhat lower levels of Zn and Cd, while
vegetables consumed as fruits or seed pods
were relatively low in heavy metal content.
Although there were significant differences
in metal content between the two sludges,
uptake of metals by the plants was not
always related to metal content in the
material. This suggests that the chemical
form may be important in evaluating sludges
for use on agricultural land.
Greenhouse Pot Studies
Greenhouse studies conducted during
this program involved investigations deal-
ing with the effects of soil pH on heavy
metal uptake by plants grown in soil amend-
ed with sewage sludge; responses of corn to
Zn and Cr in municipal wastes applied to
soil; and relationship of Zn and Cd supply
to uptake by fescue.
The first experiment was designed to
determine whether liming an acid soil would
significantly depress uptake of heavy metals
present in anaerobically digested sewage
sludge. Mountview silt loam was limed to pH
values of 5.0, 6.0, 7.0 with a 4:1 mixture
of CaCOs and MgC03- Mustard seeds were
sown and thinned to 12 plants per pot and
harvested. Leaves (3 times in 10 weeks)
were analyzed for heavy metal content.
The second experiment was conducted to
determine if Zn and Cr in several municipal
waste products becomes available to plants
after soil incubation and successive crop-
ping. Experimental procedures involved the
liming of the soil to pH 5.5, addition of
appropriate supplemental nutrients to pots
containing 3Kg of soil. Any nutrients con-
tained in the sewage sludge or compost were
in addition to the supplemental nutrients.
Various cropping sequences were used to de-
termine effects of varying the length of
time between waste application and planting,
planting after moist incubation (faster
decomposition of the waste) and other fac-
tors.
A third experiment was conducted to
determine whether varying the ratio of Zn
to Cd in the soil influences their mutual
uptake. This was based on the premise that
excess Zn prevents toxic accumulation of
Cd by first causing plant Injury. General
procedures used were to fertilize with
NH4N03, superphosphate, K2S04 in amounts to
provide the experimental amounts of N, P,
and K desired; adding Zn and Cd as chlorides
in selected quantities; and planting Ken-
tucky 31 fescue. Clippings from each treat-
241
-------
merit were harvested monthly for 4 months,
oven-dried and analyzed for Zn and Cd con-
tent.
Summary Results from Greenhouse Pot
Experiments
Abatement of Cu, Pb, and Ni In mustard
was not accomplished by liming the soil
from pH 5.0 to 7.0. However, concentra-
tions of Zn decreased significantly over
this range and Cd decreased slightly from
ph 5.0 to 6.0. Other studies are needed to
evaluate liming as a means of heavy metal
pollution abatement.
The pot experiments to study phytotoxic
levels of chromium (Cr), Cd, and Zn indi-
cated that inorganic forms of these metals
are taken up by plants in greater quantities
than from organic wastes. Whereas, Zn con-
centrations in corn increased with the rate
of Zn applied as either ZnS04 or in organic
waste, concentrations of Cr seldom exceeded
check values in the plant foliage, even
though growth was depressed. Apparently, Cr
is effectively excluded by plants with very
high soil concentrations, resulting in suf-
ficient root damage to limit growth. Cad-
mium was readily accumulated in fescue, but
growth was not depressed until concentra-
tions exceeded approximately 100 parts per
million (ppm). Details of these greenhouse
pot experiments, experimental procedures,
soil and plant characteristics, and results
have been reported and are available.
Soil Mobility Studies^
Limited studies were conducted to de-
termine the potential for contamination of
ground waters with heavy metals from land
disposal of large quantities of sewage
sludge. These experiments involved the use
of leaching columns packed with combinations
of different soils, appropriate treatments
of nutrients, selected plants, and other
factors designed to:
0 determine nitrogen (N) effects on
mobility and uptake by plants of heavy
metals in sewage sludge applied to the
columns, and
0 determine the movement in soils of
heavy metals from municipal wastes
and inorganic sources.
Results from these limited experiments
generally indicated that mobility of heavy
metals is slightly greater from inorganic
than from organic forms but is minimal even
under severe leaching situations. Based
upon these findings, it is unlikely that
controlled disposal rates of municipal
wastes applied to cropland under similar
conditions pose major threats to our water
supplies. However, the consequence of pro-
longed use on cropland and subsequent soil
management practices is not understood.
Other Experiments
Other composted waste utilization
experiments conducted as a result of the
Johnson City composting project involved:
determination of the physical and
chemical effects of municipal compost
containing sewage sludge on soil and
corn plants at the Johnson City site,
demonstrations involving the use of
composted municipal solid waste (with
sewage sludge ) on selected crops, and
0 demonstrations of using composted muni-
cipal solid waste for reclaiming poor
soils and areas such as strip mines
and road banks.
The corn experiments and the demon-
strations were conducted from about 1968
and some continued after the plant closed
in 1971. This paper will not attempt to
discuss all the demonstrations which were
conducted during the project. Selected
ones will, however, be summarized to indi-
cate the type of results obtained. The
experiment with the corn will also be sum-
marized. Additionally, summaries are in-
cluded of miscellaneous projects conducted
at the Mountain Horticultural Crops Re-
search Center, Fletcher, North Carolina,
and at the USDA Tobacco Experiment Station,
Greenville, Tennessee.
The Johnson City Corn Experiment
The Johnson City corn experiment was
conducted from 1969 through 1975 on a loam
soil and was statistically divided into
four (4) major groups comprised of 13 sub-
plots. The subplots were statistically
treated with various applications rates
combining compost and nitrogen fertilizer.
See Tables 15 and 16. Analyses completed
consisted of crop yields, soil and plant
tissue analyses for nutrient content. Soil
samples were analyzed for pH, moisture hold-
242
-------
ing capacity, moisture content, bulk den-
sity, content of organic matter, phosphorus,
potassium, calcium, magnesium, zinc, nitro-
gen, sodium, manganese, and copper. Plant
tissue was analyzed for N, phosphorus, K,
calcium, magnesium, Na, Zinc, manganese,
and copper.
In 1973, corn grain, cobs, and leaf
tissue were analyzed for lead, cadmium,
choromium, nickel, zinc, and copper.
During 1974 and 1975, selected subplots were
also monitored for plant yield, uptake of
heavy metals, soil bulk density, and soil
moisture; however, only a chemical fertili-
zer was applied to these subplots after
1973 (i.e., no compost was added).
The following conclusions were reached
based upon the data obtained during the
duration of this research. Detailed results
are available.
The application of nitrogen fertilizer
alone at a rate of 160 pounds per acre had
an adverse effect on corn yield. This can
be partially attributed to the lower pH
values of the soil in subplots that re-
ceived nitrogen at high rates of applica-
tion.
The time of compost application at
lower rates had no significant effect on
corn yields; however, at higher rates, the
time of application became more important.
This was evident after the initial appli-
cation when nutrient deficiencies were noted
on plots that had received compost at a rate
of 200 tons per acre. The highest compost
rate also caused some germination problems
in 1969 because the bulkiness of the compost
prevented the formation of a firm seedbed.
There was a rather large increase in
zinc accumulation in the soil and tissue of
plants on subplots that received compost at
high rates of application. Although the
corn in this project showed no adverse ef-
fects from the zinc, other plants with less
tolerance could be affected.
High rates of compost application had
no significant effect on uptake of nitrogen
in corn tissue. Although the compost had
a relatively low nitrogen content (less than
2 percent), high application rates resulted
in excessive accumulations of nitrogen in
the soil. Since the high application rates
did not increase the levels of nitrogen in
the plant, it is conceivable that some of
the nitrogen remained in the soil or was
leached from the root zone. In either case,
the results of high rates of compost appli-
cation may prove to have an adverse environ-
mental effect. It was beyond the scope of
this research to determine the fate of the
excess nitrogen.
The uptake of potassium was increased
at higher rates of compost application.
This increased uptake indicates that although
the potassium content of compost was low,
it was readily available to the corn plants.
There were no significant differences in
element uptake among other treatments in
this project.
These data indicated that compost had
a definite liming effect. This could be
valuable in soils with a low pH or in those
that received high rates of nitrogen ferti-
lizer. The maintenance of nearly neutral
soil conditions on the plots that received
high rates of compost also helped reduce
the uptake, of heavy metals such as zinc.
If this soil should later become acidic,
then heavy-metal toxicity could become a
potential problem.
The use of compost had a positive ef-
fect on bulk density throughout the project.
By reducing the bulk density of compacted
soils, the compost provided for better pene-
tration of air and water and thus enhanced
the development of the root system of plants
grown in this soil and reduced the energy
required for tillage.
The application of compost increased
the level of organic matter in the soil;
the addition of nitrogen fertilizer decreas-
ed this level. When both compost and ni-
trogen fertilizer were applied to the soil,
there was no significant change in the
organic matter. These results show the
importance of adding compost to the soil
to improve or maintain soil fertility.
The soil moisture content was increas-
ed by the application of compost. Moisture
in the soil is important as a solvent for
plant nutrients to enable plants to with-
stand extended periods of drought. This
finding could become the most important re-
sult of this research as we search for im-
proved methods of conserving moisture to
enhance the production of food on arid
lands.
Trends in the accumulation of heavy
243
-------
metals in selected corn plant tissue re-
vealed that metal accumulation was more
pronounced in leaf tissue than in either
grain or cob tissue when compost was
applied at rates up to 200 tons per acre.
Plants grown in control subplots had no
significant differences (except in level
concentrations) in the accumulation of
heavy metals in different plant parts.
Residual accumulation of heavy metals in
young corn plants in 1974 and 1975 showed a
reduction in uptake of metals. This de-
crease was partially due to the absence of
compost applications (the source of heavy
metals) during these two growing seasons.
However, data show that concentrations of
heavy metals persisted in the top 6-inch
layer of plowed soil.
Residual corn crops, soil bulk density,
and soil moisture content continued to
respond favorably on subplots that had re-
ceived compost applications at rates up to
200 tons per acre. Although heavy metals
persisted in the soil, their effect on corn
yields appeared to be minimal. Unpublished
data indicate no significant differences in
the content of heavy metals in corn grain
in residual crops grown in 1974 and 1975.
Tobacco Experiment at Greenville Tennessee
Since tobacco is a relatively high
value crop in terms of monetary return, the
successful use of compost in tobacco crops
might increase the compost's value. This
miscellaneous experiment was conducted to
determine whether any pathogens affecting
tobacco were present in the compost and
whether compost could replace shagnum peat
moss in a normal greenhouse potting mixture.
Thirty day old seedlings of burley
tobacco were transplanted to pots containing
the regular potting mixture, mixture in
which the peat was replaced with compost, or
100% compost. The pots were watered and
fertilized as required. Analyses consisted
of weight of leaves, plant height, stem
weight, and total weight exclusive of roots.
Results did not indicate any disease or
microbial activity adversely affecting the
tobacco plants. Growth results indicated
some increases with compost only compared to
the other mixtures.
Summary of Miscellaneous Potting Experiments
at Fletcher, N.TT
These experiments were initiated in the
fall of 1971 to measure the response of
selected vegetables and flowers to municipal
compost used in potting media mixtures. In-
formation was obtained on germination ef-
fects, vegetative growth, and moisture hold-
ing capacity. A preliminary germination
test with cucumbers', lettuce, and tomatoes
indicated no adverse effects from the com-
post. Experiments were conducted on pot
mums; tulips; vegetables including bibb
lettuce, tomatoes, and cucumbers.
In regards to growth results on the
pot mums, responses to the compost were
varied from less shoot growth and bad count
to a higher dry weight for the variety Red
Anne. In later experiments, in which ferti-
lizer was added, the compost treated pots
produced the highest number of shoots and
soil only produced the most shoot growth.
With regard to tulips, trends in the
growth results indicated that compost pro-
duced mixed responses as it did with the
mums.
In the experiments with the tomatoes,
bibb lettuce, and Gemini cukes, compost did
provide beneficial results. Results of
these experiments indicated the possibility
of compost providing some longer term
benefits to the soils as higher 2nd crop
yields were noted with the compost treatments
as compared to the others. Additionally,
compost was shown to aid water holding ca-
pacity throughout the experiments. Table
17 provides the chemical analysis of foli-
age and fruit samples of tomatoes produced
in a greenhouse soil mix and in municipal
compost.
Selected Demonstrations
Throughout the Johnson City composting
project, considerable interest was express-
ed in "demonstrating" the usefulness of
composed mixtures of MSW and sewage sludge.
Therefore, a large number of demonstrations
were established to show that compost could
be used on crops, lawns, strip mines, road-
banks, and other land areas. Results of
some of these demonstrations have been re-
ported .
The following figures are photographs
depicting selected demonstrations.
Figures 2 and 3 are photographs of 2
of more than 25 demonstrations of burley
244
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Figure 2. Burley Tobacco Grown in Compost
Amended Soil.
Figure 3. Excellent Growth Response of
Burley Tobacco to Compost.
tobacco grown on compost treated soils.
-Application rates of 12 to 60 tons of com-
post per acre were used. The results gen-
erally indicated that the compost was
beneficial and improved crop yield. Since
hurley tobacco is a relatively high value
cash crop, farmers in eastern Tennessee and
western North Carolina indicated that they
would be willing to pay for compost as an
organic amendment. A dollar per ton value
was not estimated.
The two center rows of string beans in
Figure 4 were treated with compost. While
yield information was not available, the
photograph shows the treated beans had a
definite positive response to the compost
when compared to the outer rows.
Bibb lettuce was also grown in compost
(Figure 5), although measured responses to
the compost did not show conclusively that
the compost provided beneficial responses.
However, tomatoes responded positively to
the compost by ripening quicker and yield-
ing more fruit per vine (Figure 6). Melons
were also successfully grown in compost
treated soils (Figure 7).
The corn experiment at the Johnson
City, Tennessee location was described
earlier in the paper. Figures 8 and 9 are
photographs depicting the corn growth. As
previously reported the corn responded well
to the compost with increased yields.
There were numerous individuals who
used the better grade compost (i.e., screen-
ed compost) as an aid to growing flowers.
Figures 10, 11, and 12 illustrate this use.
In Figure 10, mums were used in an experi-
ment. Compost in this experiment produced
mixed results, but generally compost had
beneficial effects on most flowers with the
exception of some acid-loving flowers such
as Rhododendrons. Compost was used as a
mulch in demonstrations on trees, shrubs,
and flowers. In these additional demonstra-
tions, compost gave excellent results, es-
pecially with roses.
The use of compost to reclaim spoiled
land areas resulted in some of the most
striking responses. A number of road banks
were reclaimed using compost after conven-
tional methods had either failed or gave
poor results. Figure 13 is one example.
The left side is the area that received the
compost. Figure 14 -;r. a photograph showing
the results from using compost in routine
245
-------
I
Figure 4. Compost was Beneficial to String
Beans.
IT4, - 4.J1&
luf i ' . ^- —! •*—
Figure 5. Compost and Bibb Lettuce.
Figure 6. Tomatoes Grew Well in Compost
Amended Soils.
246
-------
Figure 7. Melons also Grew Well in Compost.
I
•-:#:*•
'
- :• •' •
;,
N
•
Figure 9. 200 Tons/Acre of Compost Produced
Excellent Corn Yields.
Figure 8. The Corn and Compost Demonstration
at Johnson City.
247
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-
Figure 10. Compost Produced Mixed Results with Mums.
Figure 11. Compost was Used to Grow Flowers
at the Compost Plant in Johnson
City, Tennessee
Figure 12. A Beautiful Orchid Grew Well in
Compost.
248
-------
*•
.
Figure 13. Compost Often Proved Extremely Useful to Reclaim Roadbanks. The Area on the
Left was Treated with Compost.
lawn establishment, while Figure 15 shows
results obtained with compost after normal
procedures had failed. The playground area
in the photograph had required additional
top soil and reseeding for eight years
because of erosion caused by drainage.
,«*
*•-• .-. \
"••I* ,
-.4 - •* •.-.-'' • -.
* • - *• \ -•«•
Figure 15. Compost Stabilized this Play-
Figure 14. Compost was Useful in Establish- ground after Eight Years Reported
ing Lawns. Treatment with Top Soil Failed.
249
-------
However, treatment with compost stopped
the erosion and stabilized the soil. The
photograph was taken three years after
treatment with the compost.
Compost was good in reclaiming acid
soils such as strip mines. However, it also
proved helpful in reclaiming high pH soils
such as the fly ash pond depicted in Figure
16. The pH of this pond was approximately
11 when the vegetative ground cover shown
was established with the aid of compost.
The use of compost to reclaim strip
mines yielded the most pronounced effects.
Also, because the conditions of those neg-
lected lands were so poor, they were se-
lected as the first demonstration site in
1968. This was so that the unscreened com-
post could be used without fear of adverse
effects from poor esthetics.
Figure 17 is a 1971 photograph of a
strip mine area reclaimed with compost in
1968. The still barren ground is apparent
in the foreground, while the area reclaimed
with compost is also apparent in the back.
Note the sharp contrast where the compost
stopped.
In addition to the small trees and
grass seeds planted in the demonstraion,
natural vegetation was established as a
result of the compost. This natural vege-
tation could not become established on the
extreme soil conditions depicted in the
foreground of the photograph. In 1970,
an experiment was initiated to help de-
termine the minimum amounts of compost
that could be used to reclaim some of these
areas. Figures 18 and 19 are before and
after photographs. The photograph shows
the visual results obtained from using
26 tons of compost per acre.
...
J~ ' JTaCT
-,|... ... .„. *-.-- .-«:
Figure 16. Compost Aided the Reclamation of a Fly Ash Pond with High pH.
250
-------
•»•
£3
-i_i
*<:ti*t
Figure 17. Compost was Exceptional in Reclaiming this Strip-mine Area.
Figure 18. Site of the 1970 Strip-Mine
Reclamation Experiment.
(Before Reclamation)
Figure 19. Twenty-Seven Tons of Compost Per
Area Produced These Results One
Year after Reclamating the Strip-
Mine Area in Figure 18.
251
-------
In general, the many demonstrations
conducted showed the versatility of the
compost and its value as a soil amendment.
Unfortunately, a dollar value for the compost
was difficult to establish, as the intangi-
ble value may have been more than the real
economic value which could be measured from
yield responses.
Selected Conclusions
The following conclusions are summar-
ized from the various research projects
and "demonstrations" mentioned in this paper
or referenced in the bibliography.
Based upon results of the Muscle Shoals
experiments, large amounts of municipal
compost can be applied in grasslands or
croplandswith occasional positive yields
responses. With respect to the Johnson
City corn experiments and others, compost
did provide significant positive crop and
soil responses indicated by increased crop
yields and improved soil characteristics.
Muscle Shoals experiments indicated
that application of rather high rates of
sewage sludge (>50 metric tons/ha) may
increase vegetable production of some
species, but this apparent benefit may be
accompanied by increased levels of one or
more heavy metals. Since certain vegetable
species are sensitive to heavy metal accu-
mulation, toxicity may cause decreased
yields and high levels of heavy metals in
the plants. Although concentrations are
generally higher in vegetative tissue, in
some instances the reproductive plant parts
may be sinks for certain metals. The
significance of Cd and Ni concentration,
ranging from two to five times those in
vegetation from unamended plots, is yet to
be determined with regard to food chain
implications.
Total heavy metal content of a sewage
sludge does not necessarily reflect plant
availability. Transformations may occur
in soils which increase or decrease availa-
bility in these waste products. The organic
matter content and composition of the waste
material likely influence availability
depending upon the stability of the metal
complexes formed and the subsequent re-
sistance to decomposition. Apparently the
pH value of the sludge per se is not a
reliable indicator of plant availability.
However, under very acid soil conditions
(>pH 5.0), sewage sludge high in Zn content
may be toxic to plants. Inorganic sources
of Zn initially are more toxic than organic
wastes at equivalent rates of application
and constant soil pH. The consequence of
multiple applications of sludge is unknown.
Although heavy metals accumulate with
repeated treatment, the organic matrix
seems to be protective.
Results show that movement of heavy
metals in soil is greater from inorganic
than from complexed sources found in
sewage sludge under severe leaching condi-
tions; other studies indicate little
difference in mobility with normal rainfall
and minimal supplemental irrigation.
Although moderate rates of "low risk"
sludge appear to pose little hazard to
crops, continued use of municipal wastes
may ultimately result in heavy metal over-
loading, especially in some light-textured
soils.
Composted mixtures of MSW and sewage
sludge were useful in reclaiming soils •
adversely affected by strip mining, soil
erosions, and other factors which caused
conditions adverse to plant growth. In
this regards, compost increased soil
organic matter content, increased soil
moisture holding capacity, provided sta-
bility against soil erosion, and improved
other conditions which might prevent plant
growth. Positive responses to compost were
documented in a number of varied demon-
strations.
RECOMMENDATIONS AND COMMENTS
Recommendations
Municipal waste materials should be
carefully characterized with respect to
total elemental composition and solubility
prior to land disposal. Reactions of
organic wastes in soils need further study.
Although results suggest that most heavy
metals contained in wastes are rather
immobile in soils, long-term studies must
be forthcoming before the consequence of
repeated applications of heavy rates is
completely understood.
Although a number of crop species
were identified as excluders or accumu-
lators of certain heavy metals, further
study is necessary. Routine leaf analysis
is not sufficient, since certain edible
252
-------
plant parts other than leaves may be sinks
for particular heavy metals.
Based upon the Muscle Shoals research
reported, more greenhouse and laboratory
work is needed to correlate heavy metal
uptake with soil extraction procedures.
Existing extractants used for micronutrients
may not be suitable for all heavy metals.
There has been little evidence in these
studies of heavy metal conversion to more
available forms. Organic matter content
should be monitored for several more years
from plots receiving both single and multi-
ple applications of municpal wastes. Further-
more, soil samples should be extracted
during this period to determine whether
metal availability to plants is changing.
The effect of soil acidification and heating
on solubilization and mobilization of metals
is being investigated.
Guidelines must be established regarding
tolerable levels of heavy metals in food
chain components before the significance of
elevated levels in crops can be evaluated.
It also must be recognized that surface con-
tamination is a contributing factor.
Comments
Based upon responses obtained from
applying composted wastes on severely
spoiled lands such as strip mines, it would
appear that such waste products have tre-
mendous potential for aiding the reclamation
of spoiled land areas—even to the extent of
placing them back into some useful service.
With respect to the increased crop
yields and improved soil characteristics
reported in some of these experiments, the
results showed that significant positive
responses could be obtained from composted
wastes. As would be expected, the poorer
the soil the larger the response. Also,
research and demonstrations at the Johnson
City site and other locations indicated
that positive benefits could be expected
over a prolonged period from single heavy
applications of composted MSW. However,
with respect to croplands, there still re-
mains the lingering question "what are the
total effects to the food chain and ground
wastes from heavy metals and other toxic
components which might be in the wastes?"
The studies 'summarized here were not of
sufficient duration nor scope to answer
such questions.
At the time of the Johnson City
Composting project, economics and un-
certainties would have prevented farmers
paying for routine applications of compost
to crops. Although, some results did
indicate potential longer term economic
benefits, the value of these was difficult
to demonstrate when compared to the quicker
economic returns from commercial fertilizers.
There may be situations now where this
would be different. Studies being con-
ducted by Dr. Chaney, USDA, investigators
in TVA, EPA, and many others to determine
and define the complex mechanisms involved
in heavy metal migration, transformation,
uptake into plants, and associated factors
remain extremely important from at least
two points:
o If one considers applying composted
wastes, including sludges, to
improve the crop production and/or
reclaim spoiled lands and or
o If one considers applying the wastes
to lands as a disposal method.
ACKNOWLEDGEMENT
The work reported in this summary was
conducted by different investigators from
Tennessee Valley Authority; at Muscle
Shoals, Alabama; Johnson City, Tennessee;
Mountain Horticultural Research Station,
North Carolina; USDA Tobacco Experiment
Station, Greenville, Tennessee; and others.
Many organizations and persons were
involved in the varied demonstrations con-
ducted. In some cases, tables of results,
descriptions, and other information used
in this paper were directly excerpted from
reports submitted to EPA by these investi-
gators. Their contributions are ac-
knowledged. Additionally, I wish to thank
Mr. Robert E. Landreth for providing a
verbal presentation in my last moment
absence at the conference.
BIBLIOGRAPHY
1. Briedenbach, A.W. ert aj_. Composting of
Municipal Solid Waste in the United States.
Environmental Protection Agency. SW-47R.
Washington, D.C. 1971.
253
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2. Duggan, J.C. Evaluation of Compost
Demonstrations, Three Reports - August 1,
1969 to May 31, 1970, June 1, 1970 to June
30, 1971, and July 1971 to June 1972.
Tennessee Valley Authority, Test and Demon-
stration Branch, Division of Agricultural
Development (EPA Project IAG-D4-0415).
Muscle Shoals, Alabama.
3. Si vert, R. C. Utilization of Composted
Wastes in the Greenhouse. Unpublished
Report. ARS, USDA, Tobacco Experiment
Station (EPA Project IAG-D4-0415). Green-
ville, Tennessee. 1973.
4. Mays, D. A., G. L. Terman, and J. C.
Duggan. Municipal Compst: Effects on Crop
Yields and Soil Properties. Journal of
Environmental Quality. 2(l)=89-92. Jan-
March 1973.
5. Felty, J. B., and T. R. Konsler.
Summary of Information Obtained Using
Municipal Compost in Potting Soil Mixes.
Unpublished Report. Mountain Hotricultural
Crops Research Station. (EPA Project IAG-
D4-0415). Fletcher, North Carolina. 1973.-
6. Wiles, C. C. and G. E. Stone. Composting
at Johnson City. Final Report on Joint
USEPA-TVA Project. SW-31r.2. U.S. Environ-
mental Protection Agency. 1975.
7. Giordana, P. M. and D. A. Mays. Effect
of Land Disposal Applications of Municipal
Wastes on Crop Yields and Heavy Metal Uptake.
Final report prepared for EPA project (EPA-
IAG-D4-0415). In press as an U.S. Environ-
mental Protection Agency publication. 1976.
8. Duggan, J.C. and C. C. Wiles. 1977.
Effects of Municipal Compost and Nitrogen
Fertilizer on Selected Soils and Plants.
Compost Science , Journal of Waste Recycling,
Vol. 17, No. 5, Winter 1976.
9. Terman, G. L. and D. A. Mays. Utilization
of Municipal Solid Waste Compost: Research
Results at Mucle Shoals, Alabama. Compost
Science. 14:18-21. 1973.
10. Terman, G. L., J. M. Soileau, and
S. E. Allen. Municipal Waste Compost:
Effects on Crop Yields and Nutrient Content
in Greenhouse Pot Experiments. J. Environ-
mental Quality. 2:84-89. 1973
11. Soileau, J. M. and D. A. Mays. Effects
of Municpal Compsot, Lime, and Fertilizer
on Fescue Growth in Acid, Eroded Copper
Basin Soil. Tennessee Valley Authority,
Muscle Shoals Report 232. (EPA Project
EPA-IAG-D4-0415) Muscle Shoals, Alabama.
1971.
12. Duggan, James C. Utilization of
Municipal Refuse Compost. Compost Science,
Journal of Waste Recycling. Vol. 14, No. 2,
March-April, 1973.
13. Scalon, David H., C. Duggan, and S. D.
Bean. Evaluation of Municipal Compost for
Strip Mine Reclamation. Compost Science,
Journal of Waste Recycling. Vol. 14, No. 3,
May-June, 1973.
14. Duggan, J. C., and D. H. Scanlon.
Evaluation of Municipal Refuse Compost
for Ash Pond Stabilization. Compost Science,
Journal of Waste Recycling. 1974.
254
-------
UBLI 4. cwconuiittis OF SEYERM. KUMI KTAIS in SAHGO SILT IOAH (1572)
Treatment
CtMCt
ZoSO*
COMPOS t
Sludge
Zn rate.
PPM
0
40
90
160
40
80
160
40
00
160
P»
4.9
4.9
4.9
4.9
5.7
5.7
6.3
5.3
5.3
5.6
Zn
4
28
5!
106
32
47
30
29
53
93
Cu
3
3
2
3
9
15
la
10
19
27
Concentration in soil, ppm
154
1S3
Ul
Ml
Z<7
285
Ml
258
363
513
Nn
100
111
103
90
147
191
205
222
213
229
CV
0.2
0.3
0.4
0.2
0.9
1.5
1.0
1.2
2.0
5.3
PO
10
7
7
11
23
41
23
if
n
HI
1.1
1.3
1.9
1.3
1.3
2.)
2.1
1.8
1.4
2.1
" Cd
0.5
0.4
0.5
0.8
0.6
1.0
1.7
2.5
2.3
2.9
WE 7. OKI FORAGE V1E19S MO COKCEOTBATIOSS Of SEVEBAl HQWV KETW.S IK CORK FORAGE AtfO GUAM (1372)
Treatwnt
Check
ZnS04
CoapOSt
iludoe
to/Ha
0
90
180
360
90
180
360
90
180
360
•fields follow! by the saw
rest (51).
Cm
icentratior
t in corn foraoe (f> and orai
30S1B-
3493a
4Mb
JZJOa
4958bc
5S03cd
60395
5839c4
5»63d
594 5d
letter are not
41
22!
314
475
77
98
100
94.
95
97
significantly different
37
49
57
68
45
43
69
43
49
44
according
3.4
1 ft
1 R
2.9
? 1
3.4
\ s
1 1
2.5
Po
0.9
0.7
0.7
0.8
0.4
0.8
2.7
0.5
0.6
1.0
to Duncan's
-H
4.4
3.6
3.1
3.0
3.S
2.4
4.6
J.6
4.5
3.1
fj
5.1
6.9
5.9
4.1
8.1
4.6
2.6
4.0
4.5
3.1
» (0),
T-
1.0
0.9
0.7
1.0
2.3
3.3
5.3
J.7
3.5
4.1
PfM
0.3
0.2
0.2
0.3
0.7
0.9
1.1
0.9
1.0
1.2
Kukiple Range
TABLE 8. 081 YltLOS «IO CWCOnHAT10»S OF SEVERAL HEAVY HCIALS in BEAII VINES AKO POOS (1972)
Concentration in bean vines {V>
Treatment
Check
ZoSO«
Conpost
Sludge
Zn rate,
Kg/ha
0
90
180
360
90
180
360
90
130
360
Bry yield
V
9908-
1252bc
1427c
355a
1463C
l«25e
1425C
1231 be
I2346C
I537d
I. tn/Ha
P
1327f
11113
272b
31a
1060e
1034e
\42Sf
1092e
8S8d
597C
•HS-
60
184
328
499
56
8*
5Z
158
185
164
45
63
79
103
56
50
44
61
75
83
Pb
5.1
3.J
4.i
3.)
4.9
4.8
4.5
4.4
4.1
5.5
— rr
1.4
1.2
1.2
1.3
1.4
1.2
1.2
0.9
1.4
1.8
HI
5.0
4.6
4.6
4.1
4.3
4.S
3.7
6.7
5.5
5.8
and DOtH (Pi,
Pfn
Cd
5.0
6.1
6.0
5.2
4.1
4.1
3.9
6.9
6.0
6.9
0.5
0.5
0.6
0.6
0.5
0.5
0.5
1.1
1.2
1.2
0.2
0.2
0.2
0.1
0.2
0.2
0.1
0.2
0.2
0.3
to Owtin*4 HuUtpU Range tett t
TA8U 9, COKCEttTRATIOKS OF SEVERAL HEAVY HETALS IK SAKGO SlU LOW (197S)
Zn rate.
ona Soil pM
Treatnent
Cftoa
COSMOS t
Sludge
5^
0
40
80
160
40
CO
160
40
80
160
— 5
0
160
, 320
640
160
320
640
160
320 •
640
A
6.3
6.0
5.8
$.0
5.5
6.6
6.0
5.5
5.7
6.1
B
5.S
6.0
6.0
6.0
6.8
7.0
7.3
5.0
5.3
5.7
Concentration
T
2
7
12
22
(
16
19
9
19
23
& K
? 9
27 2
74 1
129 1
19 2
27 6
63 7
69 t
77 7
157 110
Cu
B
1
1
1
1
7
10
17
11
15
33
0.1
0.1
O.I
0.1
0.2
0.4
0.5
0.3
O.S
0.3
1n soil
Cd
0.1
0.1
O.I
0.1
0.4
0.)
1.2
0.7
0.5
1.9
i ft*
J
2
2
2
S
8
11
4
7
11
;iHr
2
2
2
I
10
15
24
11
13
29
Q.I
0.1
0.1
0.2
0.2
0.3
0.3
0.3
0.1
o.s
0.1
0.1
0.2
O.I
0.3
0.!
O.C
0.6
0.)
I.S
255
-------
TABLE 10. DRY FORAGE YIELDS AHD COHCEKTRATIOKS OF SEVERAL HEAVY METALS
IK COIW FORAGE ADD GHAIH (1975)
Treatment
Check
ZnSO.
*
Coapost
Sludge
Check
ZnSO.
s
Coapost
Sludge
Zn r««,
Tin-
0 0
90 360
180 720
360 1440
90 360
180 720
360 1440
90 360
180 720
360 1440
0 0
90 360
180 720
360 1440
90 360
180 720
360 1440
90 380
180 720
360 1440
"A » } application in Isilj
yields fol
Rangfc Test
owed by the se*
<5fl.
Concentration in corn foraoe and qrain, PPB
Dry yield
A
7233bc*
7984cd
7047bc
8710d
65l8a
6828b
7674c
64|4a
7038 be
7883cd
kg/ha
8
Forage
8147cd
7208bc
6670ab
6637ab
64184
6239a
6858b
6987b
6716ab
7448c
Grain
8 * 4 applications (1971,
e letter are
not sionifica
-t
30
69
93
94
38
81
74
130
158
172
36
40
49
50
46
43
44
45
48
51
mw
ntly
T
46
225
366
600
89
114
150
313
450
400
32
54
67
68
46
46
46
£2
74
64
, TO3 ,
dlfferen
-5 — r T-
0.7 0.7 4.2
0.8 0.8 4.6
0.6 0.9 4.1
1.0 0.9 4.2
1.9 2.0 5.4
1.9 2.5 4.9
2.0 3.5 4.7
3.4 4.9 4.1
4.7 6.6 5.2
5.9 7.0 5.7
0.2 0.2 0.7
0.2 0.2 .0
0.3 0.3 .0
0.2 0.3 .1
0.4 0.4 .6
0.4 0.7 .0
0.4 0.6 .3
0.8 0.9 .1
0.9 1.0 .2
1.0 1.2 .0
1974).
t according to Dun
Pb K1_
5.1 0.8
5.2 0.8
4.5 0.9
4.5 0.9
5.0 1.0
5.5 0.8
5.3 1.1.
5.5 0.9
5.1 1.0
5.0 1.2
1.1 0.6
.2 0.5
.1 0.7
.1 0.5
.2 0.8
.2 0.6
0.9 0.7
.3 0.7
.1 1.0
.3 1.0
can's Multiple
~r
0.8
0.8
1.0
0.8
o.a
0.8
1.1
0.8
0.9
1.1
0.6
0.6
o.e
o.e
0.8
0.8
0.7
0.9
0.9
1.1
TABLE 11. ORY YIELDS MID C0KCEHTRA.TIOKS OF SEVERAL HEAVY HETALS IK BEAK VIBES AHO POOS (1975)
Treatment
Check
ZnS04
Coapost
Sludge
Check
ZnSfc
Coapost
Sludge
Zn rate.
0
90
180
360
90
180
360
90
180
360
0
90
180
360
90
ICO
360
90
180
360
0
380
720
1440
360
720
1440
360
720
1440
0
360
720
1440
360
720
1440
360
720
1440
Dry yield, ko/ha
A
1658cd*
1435bc
1492bc
13656
1538c
1746d
1680cd
1224ab
K17b
1550C
558cd
483b
524c
SOS be
610d
534c
529c
4U2b
429b
438ab
B
1606C
1271ab
1232ab
929a
1630cd
l&BSca
I584C
1173ab
1028a
10804
516bc
54 5c
54 9c
358a
582cd
544C
S48c
429ab
326a
295a
Concentration
Zn Co
42
47
67
118
57
51
53
128
141
128
53
56
61
79
$8
56
54
71
82
79
Vf**
101
226
288
43
46
50
304
325
308
Pods
~5F
70
94
107
60
56
52
111
127
115
9.3
8.9
9.2
9.3
9.0
9.7
10.2
10.8
10.6
10.8
10.6
H.O
11.0
11.3
11.3
10.5
9.8
11.1
12.3
11.5
8.7
9.1
8.9
8.6
9.3
9.8
9.6
10.4
9.7
n.o
10.5
U.I
11.1
11.3
10.4
10.8
9.4
11.7
11.5
12.9
in bean vines and pods, ppn
Cd
0.2
0.2
0.2
0.3
0.4
0.2
0.3
0.8
1.0
0.6
O.I
0.1
0.
0.
0.
0.
0.
0.2
0.2
0.2
0.2
0.2
0.3
0.4
0.2
0.3
0.2
1.1
1.4
1.3
0.1
0.
0.
0.
0.
0.
0.
0.2
0.3
0.3
Pb HI
5.4
5.5
5.9
5.6
6.0
5.4
6.4
6.7
6.6
6.7
2.4
2.3
2.3
2.2
2.3
2.5
2.5
2.4
3.0
2.6
5.9
5.5
6.7
5.9
6.0
6.1
6.5
7.2
7.2
7.3
2.5
2.7
2.5
2.5
2.3
2.6
2.5
2.4
2.5
2.7
2.2
2.4
2.1
2.3
2.1
2.1
2.4
4.5
4.9
3.7
2.9
2.5
2.3
2.3
2.2
1.8
2.2
8.7
8.7
6.9
2.2
2.3
2.3
2.2
2.1
2.2
2.1
4.4
4.6
5.5
2.5
2.4
2.4
2.2
2.1
2.3
2.0
7.2
8.1
8.9
;A • 1 application in 1971: 8 • 4 applications (19?I. 19?2, 1973, 1974)7
Yields followed by the same letter are not significantly different according to Duncan's Multiple
flange Test (51).
TABLE 12. HEAVY HETALS EXTRACTED 8Y HATER AND ACIDS
FROM TUSCUKBIA AKD DECATUR SEUACE SLUDGES
Sewage Sludge
Tusctfflbia
Total, pp«"
Decatur
Total, pper
Extractant
"20
0.5 K HN03
0.5 iTHCl
OTPA
H}0
0. 5 H HK03
0.5 if HC1
DTPA"
Cu
0.4
83
83
46
516
1.0
85
77
30
740
Solubility in extractant. %
Zn
0.6
98
94
27
3640
0.7
100
100
26
1840
Cd
0.6
76
31
35
35
0.4
100
100
45
49
of total
Hi
0.9
49
56
25
43
0.8
58
58
17
40
Pb
0.1
70
69
9
1560
0.1
77
73
17
525
•Deteralned by dry ashing 2.0 grains of dry sludge for 6 hours at 470 C.
256
-------
TABLE 13. TOTAL YIELD A1ID CONCENTRATIONS OF HEAVY HETALS !« VEGETABLES,
AS AFFECTED SI SLUDGE TREATKNT (1974)
Spec lei
deans
(Wuiieotui
tuttMfi)
Okra
(rfifUAeuA
eAculen&u)
Peppers
(CdfU-ccua
spp.)
Tomato
( lycopvttizon
eACu£CA{U» Hi ] 1
Squash
(Cucwifc&x
pepo L.)
Turnip
(&UU44CB
AOpa)
Radish
(RojjAamw
iativtw L.)
Mle
(B%O£4-iC£
0£&t£eea)
Lettuce
(Uduca
Atttttfa L.}
Spinach
(Spinach
oteAaeea)
Treatment
none
Decatur
Tuscuabia
Hone
Oecatur
Tuscuabia
Hone
Decatur
Tuscuabia
(tone
Decatur
.Tuscuabia
None
Oecatur
Tuscuabfa
Hone
Oecatur
Tuscuabia
Hone
Oecatur
Tuscumbia
Hone
Oecatur
Tuscuafaia
None
Oecatur
Tuscuabia
Hone
Demur
Tuscuabia
Yield
to/plot
7
7
6
12
11
11
23
25
20
23
29
30
43
67
73
!3
14
13
..
__
—
11
11
13
—
--
._
—
—
Fruit or root cone.
ppa
In
11
31
28
40
61
43
23
41
31
15
24
20
47
83
93
39
133
7}
4g
149
121
_
-
.
-
.
Tu
7.9
7.6
7.5
9.2
9.0
8.3
10.4
13.4
10.5
3.4
3.3
2.9
12.8
15.3
12.8
5.5
8.9
6.5
3.2
3.8
3.3
__
..
--
__
--
—
—
Cd
0.0§) and potassium (%&) supplements and 200 pounds of 0-26-26
were added Co each subplot each year.
t>. Nitrogen - amoniun nitrate sulfate, 30-0-0-&S (K-P-K-S).
-------
me is. cioein/ti cowosmw or cowosi USED i* TSE
JOBKSOtl Cm COW EJUWiMEHT
nitrogen (K)
Phosphorus (P)
Pouislua (H
C»r»j> {CJ
CilclW (Ca)
tones iu« (Itgl
5oli« ()«)
Copptr (Cu
Hingiiwu
Zinc (Zn)
Concentr^don
13,000 ppo ( 1.301)
J.iOa jip. ( G.Zttl
9.700p;» ( O.S7I
46.000 w» ( «.«»)
6,000 p|» ( 0.601)
4.59S |>p«i
312 HO
1.0)3 pp«
MBit 17. CWCENT8MIOIK Of ELEBF.KTS !« FOLI«£E A«» FRUIT POBtlOHS OF G8EES-
HOUSf. WHS-TOES WKHICEO IS 4 GRtEdKOttSC SOLID Wjrutt iWO
COKPOST.* (WCRS - Fletcher, II.C. - (972)
Clwer.t
Iron
Aliatnw
Copper
KanSiraie
aicicl
Hue
Mercury
leii)
Arienic
Casoim
CliroaiUB
Selenium
var,a(inm
Boron
*0ven-dr? basts
*«HO - not detected
Greenhouse
Sod Mxture
Foilajc fruit
PPK
«9
106
14.9
392
5.3
96
0.02
6.0
O.S
2.6
3.7
0.05
no
103
pm
124
5.8
7.6
19
S.S
30
lit'
3!
NO
0.1
3.7
0.02
no
17
HunUipel
Coepost
Fol ftse
FfH
153
57
27
ie;
43
HJ
O.K
4.8
no
5.6
5.2
0.04
liO
92
Fruit
PPK
113
11. <
12.5
17
7.0
38
10)
31
HD
0.5
3.6
0.02
«0
21
258
-------
LAND CULTIVATION OF MUNICIPAL SOLID WASTE
Tan Phung and David Ross
SCS Engineers
Long Beach, California 90807
Robert Landreth
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
INTRODUCTION
Soil is a natural environment for the
deactivation and degradation of many waste
materials; and all soils exhibit a
capacity to deactivate and degrade wastes,
though not at the same rate. Land culti-
vation of waste material is a disposal
technique by which wastes are mixed with
the surface soil to promote aerobic decom-
position of the waste's organic content.
The technique is also known as landspread-
ing, refuse farming, and soil incorpora-
tion.
This paper presents a progress report
on an Environmental Protection Agency
(EPA)-sponsored study of land cultivation
being performed by SCS Engineers (EPA
contract No. 68-03-2435). Discussed will
be background information, experiences
with land cultivation of municipal solid
waste, including a case study, and associ-
ated environmental effects.
BACKGROUND
Waste deposition on land continues to
be the most widely-used disposal alterna-
tive for most types of residues. Land
disposal is expected to further increase
as regulations prohibiting discharge of
sewage sludge to the ocean are implemented,
increased pretreatment of industrial
wastewaters is required, and more stringent
air pollution control technology is
imposed.
Land disposal for most solid wastes
and sludges presently involves burying the
residues in landfills. While sanitary
landfills have been and continue to be
economically attractive, they are not
without actual and potential environmental
and social problems.
For example, as the papers in this
symposium amply demonstrate, the anaerobic
degradation of organic materials that
occurs in buried wastes usually results in
a variety of largely unpredictable and
unquantifiable by-products: gas and
leachate. If uncontrolled, these by-
products can adversely affect groundwater
quality and the surrounding environment.
Also, waste degradation and settlement
continue for many years in a sanitary
landfill, necessitating continued long-term
maintenance of the site. This maintenance
can be costly and often raises difficult
legal problems. In addition, once the site
has been used as a sanitary landfill, its
future uses are limited to continued waste
disposal or a small number of post-landfill
development options. These shortcomings
can usually be overcome, but the remedy is
generally measured in terms of dollars.
In light of these real and potential
shortcomings associated with the conven-
tional sanitary landfill disposal method,
it is not surprising that alternative
disposal techniques have been proposed and
implemented. Land cultivation is one such
alternative.
Land cultivation has been looked at
as a means of aerobically decomposing
organic waste to reduce its volume and to
prevent the formation of unwanted gases
and to minimize the intensity of leachate
problems. Also, the processes could be
carried out repeatedly on the surface of a
disposal site, thereby "recycling" the
land. Under the most ideal conditions,
proponents of land cultivation claim that
259
-------
the site could be returned to any other
land use including agriculture after cessa-
tion of disposal activities.
Although ideal conditions are rarely
met in the field, and literature on the
environmental impacts, regulatory controls,
and waste types and characteristics in
relation to land cultivation is scarce, the
practice of land cultivation has enough
promise and has had enough preliminary
successes that many industries and munici-
palities have started to land cultivate
their wastes or are planning to do so.
EPA project 68-03-2435 deals with both
municipal solid wastes and industrial
wastewaters and sludges. For the purposes
of this symposium, however, land cultiva-
tion of municipal solid wastes will be of
primary concern. In addition to the infor--
nation gathered from a literature review
and from interviews with knowledgeable
professionals, results from a case study
are also included.
LAND CULTIVATION PROCEDURES
Land cultivation has been practiced
most extensively by the petroleum refinery
industry. Oily wastes (including API
separator sludges and tank bottoms and
drilling muds) are routinely disposed of by
land cultivation at several refineries.
Also, operators of at least two commercial
industrial waste disposal facilities are
now land cultivating various types of
wastes, primarily hydrocarbons.
The process of land cultivation
appears to work in a wide range of climatic
conditions. However, warm, humid climates
offer the most favorable conditions since
biodegradation of the organic fraction is
enhanced with adequate moisture and high
temperatures. Land cultivation has been
used in cold and dry climates, but the
waste degradation rates are relatively
slower.
Land cultivation procedures at any
location are basically the same:
. A suitable site is located and prepared.
. Waste is deposited at one end of the
site and spread by track dozer in thin
(10 to 20 cm) layers over the surface.
. Waste is physically mixed with the soil
by use of a farm plow, disc, or roto-
tiller.
SITE FEATURES
Land cultivation sites are relatively
flat, with slopes generally less than five
percent. Berms or dikes are provided to
prevent surface runoff from sites receiving
industrial sludges and wastewaters.
The soils at these sites vary over a
wide range of texture and drainage charac-
teristics. One ongoing site, for example,
started operation in beach sands, although
by now the drilling muds have significantly
changed the texture of the surface soil.
Land preparation generally entails
scarification of the surface to expose as
much soil area as practical. Vegetation is
usually removed, but smaller bush and grass
may be left in place to be mixed with the
waste. Grasses in the disposal plot will
become established if the plot is left idle
for some time.
WASTE SPREADING AND MIXING
There are two basic objectives of the
land cultivation process:
. Increase the availability of the waste
for microorganisms, and
. Aerate the soil-waste mass to ensure
that sufficient oxygen is available for
biodegradation.
As a result, waste decomposition will pro-"
ceed at a rapid rate, and hazards asso-
ciated with leachate and gas generation can
be minimized.
Mixing methods and frequencies vary
depending on site specific conditions:
waste types, climate, soil characteristics,
presence of nutrients, and moisture
content. In some cases, it may be unneces-
sary to cultivate the waste with soil at
all after initial mixing. At existing
sites, mixing intervals vary from once per
week over several weeks to twice per year.
In general, the site operator judges from
the site's visual appearance when the
waste-soil mix should be recultivated. At
some sites, samples of the mixture are
analyzed to aid in this determination.
260
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Conventional farm cultivation equip-
ment is generally adequate to accomplish
the incorporation of industrial wastewaters
and sludges into the soil. However, mixing
of municipal solid waste with the soil
requires a heavy-duty soil stabilizer such
as those used in road construction.
LAND CULTIVATION OF MUNICIPAL
SOLID WASTES
In comparison to sanitary landfilling,
very little information is available on
land cultivation of municipal solid waste.
However, limited data are available on the
land application of shredded raw waste and
refuse compost.
Municipal solid wastes that have been
experimentally land cultivated are composed
primarily of paper, metals, glass, and
organics such as food wastes (garbage) and
yard trimmings (Table 1). Of course, each
locality has its own characteristic mix of
wastes depending on local conditions.
An early research study by Hart, et
al. (6) incorporated coarsely ground, un-
sorted municipal refuse into surface soil
at Davis, California, at rates of 112 to
896 metric tonS/ha (50 to 400 tons/ac) dry
weight. Nitrogen fertilizer was added to
balance the carbon-to-nitrogen (C/N) ratio
of the refuse, and the plots were kept
moist. After one year, an unidentifiable
organic residue plus identifiable fragments
of glass, metal, and plastic remained. No
odor, insect, or rodent problems were
reported, but some blowing of paper and
plastic occurred. The second year, it was
somewhat difficult to incorporate an
additional 896 metric tons/ha of waste
material into the soil since the surface
layer primarily consisted of residue from
the previous year's waste application. The
cost for this land cultivation activity was
estimated to be from $2.77 to $6.20/metric
ton ($2.51 to $5.63/ton).
A land cultivation program in Oregon
indicated that municipal solid waste can be
most easily handled if it has first been
shredded or pulverized (13). This study
found that the shredded waste should be
distributed evenly over the land surface at
rates such that it can be readily incorpor-
ated into the soil. Blowing debris can be
controlled by use of overhead sprinkler
irrigation if immediate incorporation is
not possible (14). It was noted that with
conventional field tillage equipment, an
application rate of 448 metric tons/ha
(200 tons/ac) should not be exceeded (1, 5).
With application of 896 metric tons/ha, the
unconsolidated refuse was approximately 60
cm thick. After mechanical compaction and
irrigation, the refuse layer was reduced to
a thickness of 20 cm.
TABLE 1. COMPOSITION OF MUNICIPAL SOLID WASTE, U.S. AVERAGE (12)
Material Categories
Paper
Glass
Metals
Ferrous
Aluminum
Other nonferrous metals
Plastics
Rubber
Leather
Textiles
Wood
Subtotal nonfood products
Food waste
Yard waste
Misc. inorganic waste
106 tons
53.0
13.5
12.7
11.2
1.0
0.4
5.0
2.8
1.0
1.9
4.9
94.8
22.4
25.0
1.9
10 metric
tons
48.1
12.2
11.5
10.2
0.9
0.4
4.5
2.5
0.9
1.7
4.4
86.0
20.3
22.7
1.7
Composition,
percent of
total
36.8
9.3
8.8
7.8
0.7
0.3
3.4
1.9
0.7
1.3
3.4
65.6
15.6
17.4
1.3
Total
144.0
131.0
100.0
261
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Very little of the sandy soil near
the Boardman, Oregon, site was mixed with
the refuse using the Howard rotavator when
the refuse depth exceeded 15 cm. During
cultivation, rags wound themselves around
the rotavator shaft (8, 18). All the
studies at Oregon indicated that the
application rates for shredded municipal
waste depend on waste composition and
plans for final land use.
In another study, King et al_. (8)
applied unsorted, shredded municipal
refuse along with anaerobically digested
sewage sludge to a Guelpb loam soil in
Ontario, Canada, at rates of 188 and 376
metric tons (207 and 414 tons) and 2.3 and
4.6 cm (0.9 and 1.8 in), respectively, per
ha. The refuse was first spread rapidly
on the soil surface; a furrow was plowed
about 30 cm deep into which most of the
refuse adjacent to the furrow was raked by
hand. The next furrow was then plowed to
cover the refuse. This technique resulted
in good refuse coverage, but concentrated
a relatively large amount of the refuse at
the 15- to 30-cm depth. Refuse in the 0-
to 10-cm layer was well mixed with the
soil by subsequent discings, but there was
little mixing of refuse at the lower
depths. Following this refuse application,
sewage sludge was applied, allowed to dry,
and then disced into the soil to a depth
of 10 cm. Although it was not possible to
physically mix the sludge with the refuse
to achieve a favorable C/N ratio, the
application technique used did place the
lower C/N material in an area of high root
uptake and the high C/N material at the
lower level where nitrate moving downward
was reduced due to immobilization and/or
denitrification.
Stanford (10), currently under con-
tract with EPA (OSWMP), has initiated a
three-year study near Houston, Texas, on a
multivariate trial to assess the effects
over time on crop yield and quality, soil
quality, and water quality of adding
shredded municipal refuse, dry sewage
sludge, and chemical fertilizer separately
and together. Shredded municipal refuse
(80 percent less than 20 cm nominal size)
and dry sludge were applied at rates up to
560 metric tons/ha (250 tons/ac) and 336
metric tons/ha (150 tons/ac), respectively,
to a sandy clay (pH 5.3). The wastes were
incorporated into the soil by rototilling
with a heavy-duty soil stabilizer which is
equipped with mixing blades. Clover and
grasses were then seeded. Initial
observations showed marked differences in
growth due to waste application; high
application rates produced only sparse
vegetation (Stanford, personal communica-
tion).
In the Tri Service Project at the
Navy's facilities in Pt. Hueneme, Califor-
nia, (Durlak, personal communication)3paper
waste consisting mostly of cardboard was
shredded to three different sizes (0.6-3.81,
10.2-15.2, and 31 cm) and applied at rates
of from 44.8 to 448 metric tons/ha (20 to
200 tons/ac) to two soils (sandy and
clayey). The waste was incorporated into
the surface 0 to 46 cm (0 to 18 in) deep by
a soil stabilizer. Usually one pass was
sufficient to adequately mix the refuse with
soil. Researchers on this project concluded
that land cultivation is not cost-effective
($15/ton or $16.53/metric ton), in compari-
son with other disposal methods.
SOIL INCORPORATION OF COMPOSTED
MUNICIPAL SOLID WASTE
In a sense, land cultivation of munici-
pal solid waste is akin to composting the
refuse in thin layers on the land surface.
Information concerning soil incorporation of
compost is also being investigated. Most of
this data concerns revegetation potential;
no specific information on environmental
effects, land cultivation techniques, or
costs are available.
Several investigations have evaluated
land application of compost to reclaim
drastically disturbed land and enhance
plant growth.
The composting process reduces the C/N
ratio of the refuse, stabilizes the organic
materials, and eliminates many of the
health hazards associated with raw refuse.
If the compost includes sewage sludge, it
usually contains small but significant
amounts of nitrogen and phosphorus, which
serve as nutrients for soil microorganisms
and plants.. On the other hand, composting
may concentrate certain trace elements to
hazardous levels (14).
Refuse compost applied at 35 and 70
metric tons/ha (16 and 31 tons/ac) added
organic matter and plant nutrients to sand
tailings from phosphate mining at Bartow,
Florida, as shown by'the subsequent growth
of sorghum and oat crops on the treated
tailings (7).
262
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A number of studies have used the
refuse compost from Johnson City,
Tennessee, to reclaim strip mine spoils in
Virginia (3, 9), an alkaline abandoned ash
pond (4), and an acid eroded copper basin
soil material (11). Revegetation was
possible in all these trials.
CASE STUDY - SOIL ENRICHMENT PROGRAM
The city of Odessa is located in a
semi-arid area, approximately 516 km (315
mi) west of Dallas, Texas. Like many other
cities, Odessa is faced with the situation
where the existing sanitary landfill is
nearing capacity. Available new sites near
the city are small, while larger sites are
located at considerable distance from the
city. To dispose of the 191; metric tons
(210 tons)/day of solid wastes generated,
the city has undertaken a land cultivation
program. This program has a dual objec-
tive; i.e., disposing of wastes and at the
same time improving the soil fertility by
increasing soil organic matter content and
water holding capacity of soil-waste
mixture. It is hoped that this waste
disposal by land cultivation will restore
the grazing capacity of the rangeland.
Currently, the city is leasing two
sites, comprising a total of 607 ha (1,500
ac) west of Odessa. About 92 percent of
the city's refuse is shredded to <20.3 cm
(8 in) at a site within the city, and 26
percent (about 50'metric tons/day) is
trucked 8 km (5 mi) to the land cultivation
field. Odessa's goal for 1977 is to culti-
vate 75 percent of the refuse, ultimately
rising to 90 percent.
Initial waste applications were made
in the summer of 1974 on 12.5 ha (31 ac) of
land at the rate of 100 metric tons/ha (40
tons/ac). These initial applications were
mixed into the soil by tandem disc behind
a standard farm tractor. In October 1975
a field trial was conducted to select a
rototiller for use at the site. From these
trials, a heavy-duty Buffalo Bomag MPH-1
soil stabilizer was chosen for use (Figure
1). Wastes were spread with the front
spreading blade of the soil stabilizer,
then incorporated into the loamy soil by
the rototiller in the rear. A second pass
is made later to more thoroughly mix the
soil and shredded refuse.
From December 1975 to December 1976
wastes were applied to a total of 28 ha
(70 ac) at rates ranging from 88 to 312
metric tons/ha (35 to 124 tons/ac).
Current refuse application rates average
126 metric tons/ha (50 tons/ac); the city
is still working to determine the optimum
rate.
In addition to refuse, Odessa is also
applying sewage sludge and septic effluent
on various plots at the land cultivation
field alone or in combination with refuse.
The cost was estimated at $6.Q3/metric ton
($5.47/ton) for land cultivation of munici-
pal refuse as compared to $8.85/metric ton
($8.03/ton) for landfill.
Figure 1. Municipal refuse is being spread
and mixed by a soil stabilizer (Buffalo
Bomag MPH-1)
263
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Wastes are cultivated year round, with
only one application on each plot of land.
After soil incorporation, five ranch
grasses are sown on the plot to establish
grazing for cattle. It is planned to
return the land to grazing when the grasses
become established.
PROBLEMS ASSOCIATED WITH LAND
CULTIVATION OF MUNICIPAL SOLID WASTES
Since there is little experience with
land cultivation, many of the associated
problems can only be surmised from experi-
mental work and the one ongoing project in
Odessa, Texas. In fact, some proponents of
this disposal technique claim that a prop-
erly managed and situated land cultivation
site would pose less of an environmental
threat than a conventional sanitary land-
fill. Aerobic decomposition of refuse,
which contains relatively'low concentra-
tions of heavy metals, nutrients, and toxic
substances, would tend to minimize occur-
ences of water or air pollution instances,
advocates feel. For example, in both field
and column leaching studies, Halverson (5)
found that movement of heavy metals and
phosphorus was limited, and with proper
management practices, the nitrate movement
from the refuse-treated soil could be
controlled and should not present a problem
to groundwater contamination. (Proper
management practices include compatible
site selection and design, refuse applica-
tion rates, wind and soil erosion controls,
and thorough mixing of refuse and soil.)
Problems associated with land cultiva-
tion, both observed and expected, include
the following:
EQUIPMENT BREAKDOWNS
Mechanical mixing of the wastes with
soil by a soil stabilizer often results in
rags and wires being wrapped around the
blades of the rototiller (Schnatterly,
personal communication). The severity of
this problem may be minimized if the refuse
is shredded to the dimensions (<5 cm)
recommended by Volk.
AESTHETIC PROBLEMS
Blowing of paper, plastic films, and
other light materials has been reported.
Also, the land cultivation site itself may
appear like an open dump (especially using
coarsely ground refuse) at least until the
waste's organic fraction is degraded.
Odors are not a problem although refuse
odors may be apparent before aerobic
decomposition begins. Rodent attraction
and fly propagation are not reported.
ENVIRONMENTAL CONTAMINATION
In humid areas, the relatively large
uncovered refuse area exposed to direct
precipitation may become over-saturated
and begin to leach. Both the raw and the
decomposed refuse can contribute contami-
nants that may move to groundwater. How-
ever, available information shows that
leachate from aerobically decomposed refuse
contains generally less contaminants than
leachate generated in a landfill (5).
Also, air emissions from a land cultivation
site should be no greater than those from
a sanitary landfill receiving the same
waste.
"HARDWARE DISEASE"
If the land cultivation field is to
return to pasture, as in Odessa, there
is potential health hazard to grazing
animals resulting from ingestion of metal-
lic, rubber, and other waste materials.
Volk (personal communication) suggests that
large metallic objects be sorted out and
the wastes shredded to 5 cm or less in
dimension in an effort to solve this "hard-
ware disease" problem.
EFFECTS C
ELEMENTS
PLANT GROWTH AND UPTAKE OF
As noted, one reason given for land
cultivation is the potential for returning
the land to other uses, particularly agri-
culture. Thus, it is important to deter-
mine the extent to which vegetation grown
on land cultivated plots are affected by
the presence of refuse and its degradation
by-products,
As part of this study, surface soil
and vegetative samples were taken from
control and refuse-treated plots at Odessa,
Texas, in January 1977 for chemical
analysis. Its objective was to determine
the effects of land cultivation of munici-
pal solid waste on soil chemical properties
and elemental uptake. The soil occurring
in the land cultivation field is primarily
a calcareous, well-drained Ratliff loam.
There are a variety of native weeds and
grasses in the area, but due to the limited
scope of the field study, only two species,
wild geranium (Erodium cirutarium) and
264
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wild buckwheat (Eriogonum annum) were
sampled.
Results from soil analyses showed that
land cultivation of shredded municipal
refuse increased soluble salt (EC) content
and HCl-extractahle manganese and zinc
appreciably in the soil (Table 2).
Halverson (5) reported the concentrations
of a number of elements, including sodium,
iron, manganese, zinc, copper,,boron,
phosphorus, and organic nitrogen in a
Sagehill loamy sand increased with refuse
additions (up to 896 metric tons/ha). The
concentrations of all the constituent
analyzed for the soil samples taken from
the Odessa site are in the low range of
typical soils and should not pose phyto-
toxicity or water pollution problems.
TABLE 2. CHEMICAL CHARACTERISTICS OF
SURFACE SOILS FROM THE CONTROL AND
REFUSE-TREATED PLOTS AT ODESSA, TEXAS
Constituent
Control
Treated
pH
EC, mmhos/cm
TKN, %
Org. C, %
P
Na
B
Mn
Mo
Zn
Pb
7.65
0.61
0.043
0.41
-
22.5
110
<0.2
22.5
0.05
1.8
0.09
7.63
2.12
0.066
0.69
- ppm - -
25
122
0.25
33.1
0.05
7.2
0.12
Electrical Conductivity (EC) and B were
measured in the saturation extracts;
elements in ppm were determined in O.IN^
HC1 extracts.
Plant analysis data indicate that
wild geranium and buckwheat contained
adequate nitrogen with and without refuse
treatment (Table 3). Except for boron in
wild geranium, there were no significant
differences in plant uptake due to land
cultivation. In a more detailed study,
Cottrell (1) reported that with addition
of 896 metric tons/ha shrecjded municipal
refuse to a Sagehill sand, the uptake of
zinc and boron by wheat and fescue
approached or exceeded phytotoxic levels
during the first growing season. He
also found that molybdenum uptake by
alfalfa reached levels potentially
hazardous to livestock during the first
growing season, but decreased to normal in
the second year.
Based on these preliminary findings,
it is concluded that the soil chemical
properties were not significantly affected
by the application of shredded municipal
refuse at Odessa and that concentrations of
the trace elements analyzed for wild
geranium and buckwheat grown at the dis-
posal site are within the ranges generally
reported for grasses.
SUMMARY AND CONCLUSIONS
Land cultivation of municipal solid
waste has received very little attention,
probably due to the lack of data on the
economics, productive uses, and associated
environmental problems. Optimum applica-
tion rate is about 224 metric tons/ha
(100 tons/ac). Land application of other
municipal solid wastes such as lime and
alum sludges have not been reported in the
literature. Based on its chemical proper-
ties, lime sludge could probably be used
in place of limestone as a liming material
on acid soil.
Incorporation of refuse compost into
barren lands stabilizes soil structure and
enriches organic matter content making
revegetation possible, particularly with
addition of chemical fertilizers. Gener-
ally, however, equivalent yield increases
on productive agricultural land can be
obtained more economically with inorganic
fertilizers than with largely unproven
methods such as the use of solid wastes
or refuse compost.
A "soil enrichment program" has been
initiated at Odessa, Texas, which incor-
porates shredded municipal refuse into the
surface soil alone and in combination with
sewage sludge and septic effluent. Prob-
lems encountered include equipment break-
downs during waste incorporation, impaired
aesthetics (unsightliness), and possible
development of "hardware disease" in graz-
ing cattle. These problems may be solved
if the refuse is shredded to a dimension
of 5 cm or less and thoroughly incorpor-
ated into the soil. The soil chemical
properties and forage quality at the land
cultivation field in Odessa are not signi-
ficantly affected by the disposal practice.
265
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TABLE 3. ANALYSES OF WILD GERANIUM AND WILD BUCKWHEAT GROWN ON
CONTROL AND REFUSE-TREATED PLOTS AT ODESSA, TEXAS
Element
Wild Geranium
Control
Refuse
Wild Buckwheat
Control
Refuse
3.46
0.275
4.27
0.388
2.31
0.400
2.27
0.550
- - ppm - -
- - ppm - -
Na
B
Mn
Mo
Zn
Pb
550
6
32.1
2.0
68.5
5.6
525
25
36.7
2.0
67.3
5.7
650
15.9
25.4
0.50
56
4.2
785
17
32.5
0.50
62.3
6.4
Based on available information and
field study results on the management and
disposal of municipal solid waste, the
following conclusions can be drawn:
1. Land cultivation as a disposal alterna-
tive is practiced only on a limited
scale in the U.S. The trend indicates
that there will be no significant
increase in the future.
2. Land cultivation is viable only where
soil, climatic, and environmental
conditions enable the shredded refuse
to be left partially covered for
extended periods without possibility
of environmental contamination. The
disposal program should be related to
a land reclamation project, as at
Odessa, Texas.
3. For optimum results, the municipal
solid wastes should be shredded to a
relatively small size (5 cm or less in
dimension). Presently, this degree of
shredding is prohibitively expensive.
4. Since municipal refuse has a relative-
ly high C/N ratio, application of
nitrogen (and possibly phosphorus)
fertilizers may be necessary to
enhance microbial decomposition of the
waste, and to supply the nitrogen
requirement of plants of revegetation
if agricultural production is to be
part of the project. To this end,
sewage sludge could be applied
together with municipal refuse since
it contains available nitrogen and
phosphorus and free moisture to
enhance biodegradation of the waste
material.
266
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REFERENCES
1. Cottrell, N. M. Disposal of Municipal
Wastes on Sandy Soil: Effect on Plant
Nutrient Uptake. M. S. Thesis, Oregon
State Univ., Con/all is, 1975.
2. Council on Environmental Quality. The
First Annual Environmental Quality
Report. Executive Office of the
President. U.S. Government Printing
Office, Washington, D.C., 1970.
3. Dobson, A. L. and H. A. Wilson. Refuse
Decomposition in Strip Mine Spoils.
Proc. West Virginia Acad. Sci., 35:
59-65, 1973.
4. Duggan, J. C. and D. H. Scanlon.
Evaluation of Municipal Refuse Compost
for Ash Pond Stabilization. Compost
Sci., 15 (1): 26-30, 1974.
5. Halverson, G. A. Movement of Elemental
Constituents in Sagehill Loamy Sand
Treated with Municipal Waste. M.S.
Thesis, Oregon State Univ., Corvallis,
1975.
6. Hart, S. A., W. J. Flocker, and G. K.
York. Refuse Stabilization in the
Land. Compost Science, 1J_ (1): 4-8,
1969.
7. Hortenstine, C. C. and D. F. RothwellI.
Use of Municipal Compost in Reclamation
of Phosphate Mining and Tailings. J.
Environ. Qua!., 1:415-418, 1972.
8. King, L. D., L. A. Rudgers, and L. R.
Webber. Application of Municipal
Refuse and Liquid Sewage Sludge to
Agricultural Land: I. Field Study.
J. Environ. Qua!., 3^:361-366, 1974.
9. Scanlon, D. H., C. Duggans, and S. D.
Bean. Evaluation of Municipal Compost
for Strip Mine Reclamation. Compost
Sci., ]4_ (3): 4-8, 1973.
10. Stanford, G. B. The Houston Landmix
Trial. Agronomy Absts. Annual
Meetings. Amer. Soc. Agron. Houston,
Texas, 1976. p. 34.
11. Terman, G. L., 0. M. Soileau, and S. E.
Allen. Municipal Waste Compost:
Effects on Crop Yields and Nutrient
Content in Greenhouse Pot Experiment.
J. Environmental Qua!., 2: 84-89, 1973.
12. U.S. Environmental Protection Agency.
Third Report to Congress: Resource
Recovery and Waste Reduction. Office
of Solid Waste Management Programs,
Resource Recovery Division, 1975.
p. 10.
13. Volk, V. V. and C. H. Ullery.
Disposal of Municipal Wastes on Sandy
Soils. Report to the Boeing Company.
Dept. of Soil Sci., Oregon State
Univ., Corvallis, 1973.
14. Volk, V. V. Application of Trash and
Garbage to Agricultural Lands. In:
Land Application of Waste Materials.
Soil Conservation Society of America,
Ankeny, Iowa, 1976. pp. 154-164.
267
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IMPLICATIONS OF PRICE INCENTIVES FOR SOLID WASTE MANAGEMENT
Oscar W. Albrecht
U.S. Environmental Protection Agency
26 West St. Clair Street
Cincinnati, Ohio 45268
ABSTRACT
The use of market-related incentive (or disincentive) mechanisms has received scant consi-
deration as pollution control policy in the United States, particularly in the area of
solid waste management. This paper reviews what is known about incentive mechanisms for
controlling air and water pollution and suggests possibilities for pricing (user charges)
in the management of municipal solid waste. Empirical estimates of price and income
elasticities are stated. It is hypothesized that incremental user charges for solid waste
collections and disposal would reduce the waste generation rate, enhance source separation
of recyclable materials, accelerate technological innovation, and minimize total system
costs. A properly structured price or user charge would be an equitable way of allocating
public resources and could be an efficient system for maximizing net social benefits of a
municipally provided service. Further research is needed to delineate the conditions under
which user charges would be economically feasible for solid waste management.
INTRODUCTION
The relevance of this subject to a
Symposium on gas and leachate in sanitary
landfills may not be altogether clear, ex-
cept as the theme of this Symposium
suggests a general concern over possibly
adverse effects from mismanagement of solid
waste. People are concerned about the in-
creasing amounts of solid waste for various
reasons: to some it means deteriorating
landscapes and aesthetics; others emphasize
the potential threats to health through
contamination of water supplies; still
others think largely in terms of conserva-
tion and wasted resources.
The actual adverse effects embodied in
these concepts are difficult to quantify in
an aggregate sense; thus, the related ef-
fects are mostly descriptive and with a
tendency toward use of emotional terms.
There is, however, an indicator that sug-
gests the importance of solid waste, and
that is public outlays or costs. Expendi-
tures for managing solid waste rank seventh
among state and local budget items on a
per capita basis (1). Overall expenditures
for pollution control of solid waste (in-
cluding collection and disposal) were esti-
mated at over $5 billion in 1975 (2). These
large outlays for solid waste management
mean that other badly needed community ser-
vices and projects must be reduced or post-
poned.
The increasing amounts of solid waste
and mounting public costs for managing it
frequently evokes the question "What can
be done about it?" There is no general
concurrence on this issue and no broad pub-
lic policy has as yet been established to
deal with the problem. Implicit in the
language of past national legislation was
the need for source reduction and conser-
vation, but government research and imple-
mentation program efforts to "date have
concentrated on handling and disposing of
solid waste after it has been generated
(3). In recent years, the recapturing of
materials from the waste stream, including
converting combustible materials to energy
has received increased attention. These
programs, however, continue to neglect the
issue of source reduction and may be only
"second-best" solutions for achieving
268
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resource conservation.
A quick glance at past research
activities will show that large sums of
public monies have been expended to deve-
lop technology for managing solid waste
after it has been generated, while there
has been a great lack of research on the
source of the problem—the solid waste
generator. Of some 500 available publica-
tions listed by the Office of Solid Waste
(U.S. EPA), over 30 percent relate to solid
waste collection and disposal. Only about
a dozen reports touch on source reduction,
and these mostly on technological possi-
bilities for waste reduction. The kind of
source reduction referred to in this paper
relates to the behavioral changes needed
to bring about a reduction in the current
post-consumer solid waste generation rate
of 3.75 pounds per day, and the projected
rate of 5 pounds per day by 1990 (4).
PAST RESEARCH ON ECONOMIC INCENTIVES FOR
SOLID HASTE MANAGEMENT
Someone might ask "What more is there
to investigate about the behavior of solid
waste generators?" After all, we have
studied the attitudes of housewives toward
solid waste and recycling, the problem of
abandoned automobiles, and throw-away bever-
age containers, to mention a few. What has
been generally lacking in these studies,
however, is an in-depth analysis of the be-
havior of waste generators, in a framework
of demand for collection and disposal of
their solid waste.
It may be useful, before embarking
upon a discussion of the implications of
incentives, to define what is meant by an
"incentive." The dictionary defines an in-
centive as "that which incites to action."
In an economic context, an incentive
is that which encourages individual or cor-
porate action in expectation of a potential
gain or loss. A price is a form of incen-
tive or disincentive mechanism which the
decision-maker translates into potential
gains or losses.
A price may relate to either the supply
or demand side of a market activity. In
the area of solid waste, the U.S. EPA's re-
research has been mostly with regard to the
supply of collection and disposal services;
for example, the use of wage incentives to
increase worker productivity (5). The re-
sults of this study should be useful to
large cities which tend to have municipal-
ly-operated collection and disposal ser-
vices (6).
Studies on the demand for waste
collection/disposal services have addressed
incentives for the most part in only a tan-
gential fashion; for example, the relation-
ship between backyard vs. curbside pickup,
the relationship between frequency of pick-
up and volume of waste generated, or the
effects of educational and publicity cam-
paigns on source separation (7). The
feasibility of using prices to modify the
attitudes and behavior of solid waste gen-
erators has been generally overlooked.
Perhaps the first attempt to study the
relationship between charges and waste gen-
eration was by Hirsch, using data for the
St. Louis County-City area (8). His meth-
odology and approach did not fully address
the issue of user charges, however. The
cost model included number of pickups as a
proxy for quantity; thus average cost of
pickup was represented. This variable
turned out to be nonsignificant (assumed
constant). Thus, the higher cost observed
for the user charge probably reflected only
the associated administrative costs and
not the net effects of the charge system.
At the time of the study, only 7 of the 24
communities in the St. Louis area had a
"user or service" charge, and none of these
were incrementally structured.
The University of Chicago, under a
grant from the U.S. Public Health Service,
conducted a study on the relationship be-
tween income and residential refuse (9).
The particular emphasis in that study was on
the relationship between income and residen-
tial waste quantities set out for collec-
tion. Price effects could not be observed
as the City of Chicago financed collection/
disposal service from general tax revenues.
The study showed that quantity of
waste was positively related to income,
with an average per capita income elasti-
city of 0.53 for selected weeks. Thus, a
a ten percent increase in real income sug-
gested a five percent increase in household
solid waste set out for collection. The
elasticity ratio appeared to have a season-
al pattern; however, with a lower ratio in
winter months and also lower for low in-
come households. The researchers suggested
that residential refuse may consist of two
components: (1) a "basic" quantity that is
269
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Invariable with regard to income and season
of the year, and (2) an "excess" component
that is more sensitive to'-'income and race."
A recent U.S. EPA supported study by
the University of California investigated
the demand for waste collection in 20
California communities (10). The results
indicated a price elasticity of demand of
0.44. This suggests that a ten percent
increase in price or user charge would re-
duce waste set out for collection by 4.4
percent. The accuracy of the estimate must
be taken with caution, however, because
average price was used as a proxy for in-
cremental price. Since average price tends
to overstate marginal price as perceived by
consumers, the price elasticity ratio was
probably underestimated.
The California study had several
deficiencies including inadequate sample
size. The number of communities with an
incremental charge (i.e., a charge per bag
or can) was limited to four, and only one
community (San Francisco) had a charge
structure approaching a true user charge.
The possibility that simultaneity affected
the results must also be considered. Thus,
the results based on California communities
can hardly be indicative of a national re-
sponse to user charges.
USE OF INCENTIVES FOR AIR AND HATER
POLLUTION CONTROL
Incentives for pollution control have
received considerably more attention in
Europe than in the United States. The ef-
fluent charges assessed by the Genossen-
schaften (Water Resources Associations) in
the Ruhr industrial area of West Germany
are frequently cited as an example. These
charges are not true user charges in the
strict sense, however, as the charges tend
to be based on the average cost of treating
effluent (11). The French system more
nearly meets the requirement that the
charge relate incrementally to the benefits
received. The effluent charges are based
on the impurity of the effluent, and ad-
ditionally, there are fees for users of
water based on the quantity and quality of
water withdrawn. Thus, the system also
provides information on the consumer's
"willingness to pay" for purer water.
In the U.S., user charges specifically
directed at water and air pollution control
are practically nil. The results of an
empirical study on the use of sewer sur-
charges may have important implications
for water pollution control, however (12).
Data from 34 cities having sewer surcharges
were analyzed by the Water Resources Re-
search Institute of the University of
North Carolina. The results showed that:
(1) a 45 percent reduction in pounds of BOD
could be expected from a modest surcharge
of 2.7 cents per pound of BOD where no sur-
charge existed previously; and (2) an ad-
ditional increase of 10 percent in the
surcharge would result in a further reduc-
tion of 8 percent in the BOD loading. This
suggested an average price elasticity of
about 0.90, starting with a zero charge.
The response to sewer surcharges does not
necessarily imply that a similar response
would result from stream charges; but it
does lend credence to the theory that in-
centives such as effluent charges will be
included in production decisions affecting
waste generation and disposal (13).
An advantage of incentives that should
not be overlooked is the potential stimulus
they provide for technological innovation.
This kind of stimulus for process changes
and waste treatment or control is not pro-
vided by a direct regulatory approach. By
that approach, the inclination of waste
generators is to sit back and let the gov-
ernment suggest the technology to meet
environmental standards. This puts the
onus on the governmental regulatory au-
thority to be the "know-it-all" technology
expert.
Implementation of user or effluent charges
for water pollution abatement is just
beginning in the U.S. The impetus for this
is provided by the Water Pollution Control
Act Amendments of 1972 (14). Section 204
of the Act requires that a municipality
initiate a user charge reflecting the
user's contribution to the total waste load
and associated costs in order to qualify
for federal assistance in the construction
of water treatment facilities.
Our experience with incentives for air
pollution control is even less than in the
water area; however, an interesting example
of the potential for incentives was report-
ed recently (15). The case involved the
electric utilities, and the suppliers and
distributors of fuel oil for these utili-
ties. The energy crisis and fuel shortage
in the winters of 1972-73 and 1973-74
motivated suppliers and distributors in the
270
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New York City area to request variances or
exceptions to the existing air pollution
laws on the justification that low sulfur
fuel oil was in short supply. The New York
City EPA perceived that granting the vari-
ances could result in windfall profits to
suppliers and distributors because it would
permit delivery of a lower priced fuel at
a previously contracted delivery price.
The Agency, however, had to depend on the
industry for the information concerning the
availability of low-sulfur fuel oil. The
true situation became known when the New
York City EPA decided to grant variances
but with the stipulation that the City re-
ceive a surcharge of 75 cents per barrel
for fuel oil containing between 0.3 and 1.0
percent sulfur, and $2.00 per barrel for
oil containing between one and two percent
sulfur. The effect of this was that by
the end of the 1972-73 winter one of the
major suppliers had found it necessary to
deliver only a third of the amount of high
sulfur oil it originally estimated was
needed, and another major supplier was able
to limit his distribution to half the
amount originally estimated.
IMPLICATIONS OF A PRICE POLICY FOR
SOLID WASTE MANAGEMENT
The American Public Horks Association
in its recent publication indicated that
perhaps 30 percent of the cities in the
U.S. rely on some form of service charge to
finance solid waste collection (T6). The
APWA notes that the use of user charges may
be declining. The trend is obscured, how-
ever, because municipalities define a user
or service charge in various ways; A re-
cent study by Columbia University reported
that only about 13 percent of the communi-
ties surveyed had an incremental or vari-
able user charge (17). The percentage of
national population affected was even lower
as large communities and cities depended
more heavily on general taxation.
Given that a user charge is an equit-
able method of charging for a service, the
reasons why its use is not more prevalent
are not entirely clear. Aside from the
usual objections to user charges; for ex-
ample, that solid waste collections benefit
the public in general and therefore should
be financed by general taxes, or that such
charges are regressive, there are probably
also more subtle reasons why municipal
officials are reluctant to adopt user
charges. Possibly, financing public
services by general taxation maintains a
climate in which members of society can
hope that somehow their individual cost is
less than the average taxpayer's. Society
as a whole must assume the costs in propro-
tion to the services demanded, but it has
been shown that local politics are such
that individual costs can be disproprotion-
ate to the benefits obtained (18). Another
reason why local officials may resist user
charges is because they lack information on
the ultimate effects.
Studies by the U.S. EPA suggest that
user charges for solid waste management are
theoretically feasible (19). Studies by
academic researchers generally supported
this thesis (20). Moreover, the general
conclusion is that public officials by
rejecting incremental user charges have en-
couraged households to generate larger
quantities of waste (21). The perceived
need for pricing solid waste management is
not limited to academia, however, as state-
ments to this effect by persons having
close contact with solid waste problems can
frequently be found in the press.
RESEARCH NEEDED TO EVALUATE USER CHARGES
The key question for which an answer
is needed is "Does a properly structured
incremental user charge result in lower
total system costs and increased net social
benefits when compared with other systems?"
Any policy recommendations for or against
pricing solid waste must first be able to
answer that question.
In the U.S. EPA's Decision-Makers
Guide in Solid Waste Management, it is sug-
gested that the basic issues in solid waste
management can be categorized as costs,
environmental factors, resource conserva-
tion, and institutional factors (22). User
charges are given as one alternative which
may enable localities to balance costs with
revenues, make citizens aware of management
costs, and provide impetus for efficient
operations. On the other hand, the Guide
notes that user charges are more complex
to administer and can cause "problems" for
people on fixed incomes. The feasibility
of user charges as a waste reduction policy
is not mentioned; however, and local deci-
sion-makers are not provided with the set
of conditions under which user charges
would or would not be efficient.
The following aspects of a user charge
271
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system are important to local solid waste
managers in reaching a decision:
1. Hill an incremental user charge
provide incentive for a reduced waste
generation rate; and if so, in what
form will the reduction occur and
what will be its magnitude?
2. Will an incremental user charge
provide the incentive to households
to source separate recyclable mater-
ials; and if so, what will be the
effect on an optimal design for end-
of-pipe resource recovery systems?
3. Will an incremental user charge
provide incentive to waste managers to
adopt efficient management techniques;
and if so, will this include increased
innovation of new technology?
4. Will an incremental user charge
induce waste generators to switch to
alternative disposal options, includ-
ing food disposers, compactors, com-
posting, burning, littering, and in-
creased bulk set-outs; and if so, what
costs to society are associated with
these alternatives?
5. Will an incremental user charge
impact on household purchases of
optional levels of service (e.g.,
set-out, frequency, pickup location,
etc.)?
SUMMARY
The research literature suggests that
effluent charges and emission fees are
feasible incentive instruments for control-
ling water and air pollution. The potenti-
al of user charges as a similar incentive
strategy for solid waste management has
not been seriously considered nor research-
ed. User charges for collection of resi- •
dential solid wastes might substantially
reduce the quantity of waste having to be
disposed of or recycled, with resulting
lower total system costs. This might be
achieved, for example, through an increased
propensity by households to source separate
recyclable wastes, increasing the import-
ance of decisions regarding type of pack-
aging and product durability, and of de-
cisions affecting the generation of yard
wastes, such as planting and fertilizing of
grass, trees and shrubs. A few communities
presently employ various pricing schemes,
but the full effects of these are not fully
known. Policy recommendations concerning
user charges should not be made in the
absence of this information.
In summary, the key issue is whether
implementation of a user charge system for
solid waste collection makes a community
and the Nation better or worse off than
before. Implicit in this is the question
of whether individual freedom of choice is
preserved. A user charge system retains
the concept of consumer sovereignty while
regulatory approaches such as mandatory
deposits, production or disposal taxes, and
licenses or permits based on approved tech-
nology and discharge standards reduce in-
dividual freedom of choice. A fully struc-
tured user charge is generally accepted as
an equitable method of allocating public
resources.
Widespread adoption of user charges
might not only reduce solid waste quanti-
ties and adverse effects on the environment,
but could also mean an overall reduction in
expenditures for solid waste; thus permitt-
ing scarce resources to be shifted to other
social needs such as education, medical re-
search, and rapid transit. The waste gen-
eration rate in San Francisco is cited as
an example of what an incremental user
charge system can achieve (23). Household
solid waste collections in that city amount-
ed to 699 pounds per capita in 1970, in
contrast to the average of 937 pounds for
California communities where general reve-
nue financing predominated. In San Leandro,
California, another community having an in-
cremental user charge, the residential
solid waste amounted to 60 percent less
than in communities without a user charge
(24).
To fully research the effects of user
charges will require substantial funds.
The parameters of variables comprising the
complete system should be determined. I-
deally, this would involve field experi-
ments where the variables of interest are
controlled. The greater investigative
power of such experiments would produce a
larger payoff in predictive reliability.
This kind of research, directed toward
human behavior--the real source of the
solid waste problem—is long overdue.
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REFERENCE
1. U.S. Department of Commerce, Bureau of
the Census. "Government Finances In
1974-75." GF 75, No. 5.
2. U.S. Government Printing Office,
Superintendent of Documents. Environ-
mental Quality, Seventh Annual Report
of the Council on Environmental
Quality. September 1976, p. 167.
3. The Solid Haste Disposal Act. P.L.
89-272, and the Resource Recovery Act
of 1970, P.L. 91-512.
4. U.S. Environmental Protection Agency.
Third Report To Congress: Resource
Recovery and Waste Reduction"! EPA"
SW-161, 1975, p. 10.
5. Shell, Richard L., and Shupe, Dean S.,
"Incentives for Solid Waste Collection
Personnel." University of Cincinnati,
Department of Mechanical Engineering.
Draft report to U.S. Environmental
Protection Agency, Grant No. R-801617.
6. American Public Works Association.
Solid Waste Collection Practices, 4th
Edition.Chicago, Illinois, 1975,
p. 237.
7. For example, the U.S. Environmental
Protection Agency, Office of Solid
Waste Management Program MIS/Resi-
dential Collection System Studies, and
the Community Awareness Program in
Somersville and Marblehead, Massachu-
setts.
8. Hirsch, Werner Z. "Cost Function of
a Government Service: Refuse Collec-
tion" Review of Economics and
Statistics, Vol. 47, February 1965,
pp. 87-92.
9. U.S. Environmental Protection Agency.
Socio-Economic Factors Affecting
Demand for Municipal Collection of
Household Refuse. EPA-670/9-73-085,
August 1973.
10. University of California, Berkeley.
Comprehensive Studies of Solid Haste
Management: Final Report. SERL No.
72-3, May 1972.
11. Macaulay, Hugh H., and Yandle, T.
Bruce, Jr., "An Economic Evaluation
of Water Quality Management System.,"
Clemson University, Clemson, South
Carolina. Water Resource Research
Institute Report No. 58, October 1975,
p. 45.
12. Elliott, Ralph 0., and Seagraves,
James A. The Effects of Sewer Sur-
charges on the Level of Industrial
Wastes and the Use of Water by In-
dustry.North Carolina State Univer-
sity, Raleigh, North Carolina. Water
Resource Research Institute Report No.
70, August 1972.
13. Meta Systems, Inc. Effluent Charges:
Is The Price Right? Cambridge. Hass-
achusetts, September 1973.
14. Federal Water Pollution Control Act
Amendments of 1972. P.L. 92-500, 92nd
Congress, S. 2770, October 18, 1972.
15. U.S. Environmental Protection Agency.
Financial Incentives and Pollution
Control: A Case Study!EPA-600/5-75-
007, April 1975.
16. American .Public Works Association,
Solid Waste Collection Pratice, 4th
Edition. Chicago, Illinois, 1975, p.
262.
17. Columbia University, Graduate School of
Business. "Evaluating the Organization
of Service Delivery: Solid Waste
Collection and Disposal." Preliminary
Report to the National Science Founda-
tion, No. SSH74-02061A01, October 1975,
p. 11-3.
18. Black, David E. "Cause of Local
Property Tax Discrimination." Southern
Economic Journal, Vol. 43, 3.
19. Environmental Dynamics, Inc.
Development of an Economic Analytical
Framework for Solid Waste Policy
Analysis.U.S. EPA/600/5-75/014; and
Abt Associates. Evaluation of the
Feasibility and Economic Implications
oT Pricing Mechanisms in Solid Waste
Management. U.S. Department of Com-
merce, National Technical Information
Service. PB-239 116/LK, October 1974.
20. For example, see Bonus, Holger. "On
the Consumer's Waste Decision," Zeit-
schrift Fur Die Gesampte Staatswlssen-
schaft., 128(2), 1972, pp. 257-68.
273
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21. Wertz, Kenneth L. "Economic Factors
Influencing Households' Production of
Refuse." Journal of Environmental
Economics and Management, Vol. 2, 4;
April 1976, pp. 263-72.
22. U.S. Environmental Protection Agency,
Decision-Making Guide in Solid Waste
Management. SW-500, 1976.
23. Wertz, Kenneth L. p. 266.
24. Hudson, James F. Department of Civil
Engineering, Massachusetts Institute
of Technology. Personal letter, June
16, 1975.
274
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EFFECTS OF DECOMPOSITION GASES ON LANDFILL
REVEGETATION AT TVA'S LAND BETWEEN THE LAKES
J. Carroll Duggan, Environmental Scientist
David H. Scanlon, Staff Forester
Tennessee Valley Authority
Chattanooga, Tennessee
INTRODUCTION
Landfilling is the most common method
for disposing of solid refuse in the
United States, but information on special
methods or techniques required for
revegetation of such sites is very limited.
On its Land Between The Lakes, the Tennessee
Valley Authority (TVA) in 1975 began
research on the revegetation of a sanitary
landfill to improve the appearance and
allow productive reuse of the land for the
benefit of people and wildlife. The
project involves determining the various
kinds of gases that result from decompo-
sition of landfilled solid wastes,
measuring the relative volumes of these
gases, and assessing their effects on the
survival and growth of various species of
grasses, shrubs, and trees.
TVA developed Land Between The Lakes
in southwestern Kentucky and northwestern
Tennessee as a national demonstration of
the utilization of a region's available
resources for a combination of outdoor
recreation, resource management, and
environmental education. It is a continuing
development and demonstration project, and
the new concepts and methods being tried
and tested at Land Between The Lakes are
helping establish criteria for the develop-
ment of improved recreational facilities
and environmental education programs
throughout the United States.
Land Between The Lakes is a
170,000-acre peninsula between Kentucky
Lake on the Tennessee River and
Lake Barkley on the Cumberland River.
Roughly 40 miles long and 8 miles wide,
it is about 85 percent forested and has
300 miles of shoreline.
The recreation potential of this site
has been partially developed with numerous
family campgrounds, lake access areas, and
group camps. More than 2.1 million visitors
were attracted to Land Between The Lakes in
1975.
About 20 percent of those who visit
Land Between The Lakes participate in its
formal and informal environmental education
programs, for the area also provides an
outdoor classroom for enhancing environ-
mental awareness. School groups can come
for resident or single-day programs in
environmental eduation at the 5,000-acre
Environmental Education Center. Casual
visitors are also provided opportunities
for learning experiences in the management
of timber and fish and wildlife, control
of flooding and erosion, and development
of environmentally desirable technologies
such as the use of solar energy.
Because of the relative isolation of
the area and because of its size and the
large number of visitors it receives,
Land Between The Lakes operates and
maintains its own water supplies, waste-
water treatment facilities, solid waste
collection system, and sanitary landfill.
In keeping with the emphasis on environ-
mental education, these facilities are
used to develop and demonstrate
environmentally acceptable principles
and practices of sanitary engineering.
275
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PURPOSE OF RESEARCH AND
DEMONSTRATION PROJECT
The principal difference between
landfills and other disturbed sites is
that covered organic refuse produces
decomposition gases in varying quantities.
These decomposition gases include carbon
dioxide, methane, and smaller amounts of
hydrogen, carbon monoxide, nitrogen, and
oxygen. According to Flower (1975)1, the
survival, growth and condition of plants
have been unusually poor at landfills where
moderately high concentrations of gas have
been detected.
TVA began research at the Land Between
The Lakes sanitary landfill in late 1975
to test the adaptability of various species
of grasses, trees, and shrubs to conditions
associated with sanitary landfills; to
obtain information on variability in
tolerance of various plants to landfill
conditions; and to select species, families,
and individuals that demonstrate superior
potential for landfill revegetation for use
in breeding and for use in revegetating
these areas. The project involves
identifying the decomposition gases
produced in the Land Between The Lakes
landfill, measuring their volumes, and
evaluating their effects on the survival
and growth of vegetation.
DESCRIPTION OF LANDFILL
The present 16-acre landfill has been
in continuous operation since its establish-
ment in 1966. At first, area landfilling
was the primary method used; however, since
1971, the trench method has been used.
During the peak of the recreation season,
as much as 70 tons of solid waste is
disposed of in the landfill. The waste
load at other times is about 2 tons per
week. The waste is high in organic content
from food residues, fish scraps, and
packaging materials. Soil at the landfill
site is of the Tuscaloosa Formation
1.
Flower, F. B. Case history of landfill
gas movements through soils. Paper
presented at Research Symposium on Gas
and Leachate from Landfills: Formation,
Collection and Treatment. Cook College,
Rutgers University, New Brunswick,
New Jersey, March 25-26, 1975.
(cretaceous) and is composed of unconsoli-
dated clay, silt, sand, and gravel. The
thickness of the soil at the landfill site
exceeds 75 feet. It is underlain by the
Fort Payne Chert (Mississipian).
According to the United States
Geological Survey report on the region,
water in the overburden of this formation
generally has a pH of about 6.5, a hardness
of about 75 mg/1, and a bicarbonate content
of 75-100 mg/1. Ground water level is
estimated to be 50 feet below the surface.
PROCEDURES
A plot 184 feet wide and 312 feet long
was selected. Sixteen 20-foot square
subplots were located over a recently
finished refuse cell that had an average
depth of 15 feet.
Varied species of woody plants that
can be established on disturbed sites or
that have been successful in artificial.
reforestation were chosen for trial:
Shrubs
Runner oak (Quercus pumila, Q_. minima)
Bear oak (£. ilicifolia)
Dwarf chinkapin oak (C^. prinoides)
American beautyberry (Callicarpa americana)
Silky dogwood (Cornus amomum)
Common chokecherry (Prunus virginiana)
Black-fruited chokecherry (?_•]/. melanocarpa)
Allegheny chinkapin (Castanea pumila)
Autumn-olive (Elaeagnus umbellata)
"Western sand cherry (Prunus besseyi)
Trees
Sycamore (Platanus occidentalis)
Carolina buckthorn (Rhamnus caroliniana)
European alder (Alnus glutinosa)
Tupliptree (Liriodendron tuliptfera)
White ash (Fraxinus americana)
Persimmon (Diospyrus virginiana)
Chinese chestnut (Castanea mollissima)
Sawleaf zelkova (Zelkova serrata)
Sawtooth oak (Quercus acutissima)
Redbud (Cercis canadensis)
The experiment with woody plants
involved a randomized complete block
design with separation of the tree and
276
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shrub species within each block. Six
replicates were used, four on the landfill
and two as controls. On the landfill,
12 plant row plots were used with
8 by 8-foot spacing. The area available
for the control blocks was limited, and
reductions were made to four plant plots
per species with a 6 by 6-foot spacing.
All shrubs and trees were planted in March
and April 1976.
In addition to the woody plants, six
species of grasses—redtop (Agrostis alba),
timothy (Phleum pratense), annual ryegrass
(Lolium multiflorum), perennial ryegrass
(k« Perenne). orchardgrass (Dactylis
glomerata), and tall fescue (Festuca
arundinacea) var. Ky 31—were tested. The
grasses were planted in a randomized
complete block design using 20 by 20-foot
plots and two replications of the six
species. Grasses were sown in September
1975 at a rate of 0.5 pound per plot
(equivalent to a rate of 54 pounds per
acre). The plots were fertilized at a
rate of 400 pounds per acre with 15-15-15
fertilizer and were moderately mulched
with oat straw.
EVALUATION
Woody plants will be evaluated yearly
on a plant-by-plant basis to determine
survival and growth. Total heights of all
plants were recorded in May 1976. Other
evaluations will be made as necessary and
may include evaluations of traits of
flowering or fruiting, foliar color, or
other factors. The results will be
analyzed and interpreted in correlation
with information from the gas monitoring
program. The composition and concentration
of gas in the root zone of the woody plants
will be determined, and vegetative response,
including variations by species or seed
sources, will be analyzed for correlation
with data on gases.
Grass plots will be evaluated yearly
in late fall for variation in cover density
as determined by point sampling techniques.
Production of dry matter will be determined
from clipping samples as necessary. Data
on herbaceous response will be analyzed for
correlation with data on the quantity and
composition of gas in the root zone, and
visual observations of effects such as
discoloration of foliage that might be
caused by gases in the root zone will be
documented.
Temporary gas sampling points were
located throughout the landfill (see
Figure 1). The test plots of grass will
be monitored most intensively to establish
criteria for sampling frequency and
location. Permanent gas sampling stations
will be established to improve the effi-
ciency of data collection and the quality
of data. Field analyses will be performed
with fyrite oxygen (0_) and carbon dioxide
(CO?) analyzers. Combustible gas will be
analyzed with the MSA explosimeter.
Additional samples of gas will be analyzed
by gas chromatography. In preliminary
results, concentrations of explosive gases
have been below detectable limits, and
concentrations of CO- and 0« have been
within the non-stress range (CO, <2%,
0 18-20%).
277
-------
-N-
ro
•^4
OO
FIGURE 1
GAS SAMPLING LOCATIONS AT LAND BETWEEN THE LAKES
SANITARY LANDFILL
o
ac.
1
I0V Ifl
1
|
1
1
I
,28'-]c
1
1
1
1
1
1
«4
i
i
SHEO r
LJL
72 16 2O
3 7 II IS 19
> • • • 4
2 6 10 14
,
TTT-r~f-rTT -~T T ~r T T T ~r
J 1 1 1 1 ^ I 1 1 1 g \ 1 1 1 /? 1 1 I/?-
/ I 1 1 \l 1 1 1 \J> \ I 1 \g i 1 1 /7
'
1
V
00
1
1
1
CONCRETE
MARKER
-SAMPLING LOCATIONS
-------
LIST OF ATTENDEES
Mike Adams
Browning-Ferris Industries
P.O. Box 3151
Houston, Texas 77001
Felix G. Andrews
City of North Hampstead
c/o City of North Hampstead
North Hampstead, New York
Peter J. Andros
Morris and Andros
25 Albany Post Road
Hyde Park, NY 12538
Nicholas S. Artz
Mid-America Regional Council
20 West 9th Street
Kansas City, MO 64105
Frederick P. Baggerman
Zurheide-Herrmann, Inc.
4333 W. Clayton Avenue
St. Louis, MO 63110
Trygve K. Bakkotn
Waste Management of Illinois
P.O. Box 563
Palos Heights, IL 60463
Robert F. Balch
Kimberly-Clark Corporation
2001 Marathon Avenue
Neenah, VII 54956
Everett L. Balk
Crafton, Tull & Associates
P.O. Drawer 549
Rogers, Arkansas 72756
L. Banias
Underwood McLellan & Assoc.
1479 Buffalo Place
Winnipeg, Manitoba R3T 1L7
CANADA
Carl Batliner
Armco Steel Corporation
P.O. Box 600
Middletown, OH 45043
Charles Beale
West Michigan Environ. Action
3006 House Street NE
Belmont, MI 49306
Archie E. Becher, Jr.
Becher-Hoppe Engineers
1130 Grand Avenue
Schofield, HI 54476
Alfred H. Beck
City of Kansas City, Missouri
414 East 12th Street
Kansas City, MO 64106
David Beck
Andrews Engineering
1320 South 5th
Springfield, IL 62703
John D. Beck
Baltimore County Maryland
County Office Building
Towson, MD 21204
Richard B. Beck
Burns & McDonnell
P.O. Box 173
Kansas City, MO 64141
William f. Bell
Austin Brockenbrough and Associates
114 East Cary Street
Richmond, VA 23219
G. A. Bennett
Dowel! Division, Dow Chemical
P.O. Box 7
Oologah, OK 74053
Albert Bergamini
Demopulos and Ferguson
600 Petroleum Tower
Shreveport, LA 71101
Robert T. Berry
Burns & McDonnell
Box 173
Kansas City, MO 64141
279
-------
Mark J. Bertane
American Coccoio Company
5100 Suffield Court
Skokie, IL 60076
Clark Bledsoe
Louisville and Jefferson County
Department of Public Health
P.O. Box 1704
Louisville, Kentucky 40201
H. J. Boesch, Jr.
Boesch Consulting Engineers
213 Tomahawk Court
Bolingbrook, IL 60439
Rudolph Boksleitner
U. S. Environmental Protection Agency
U.S. EPA/ORD (MD-5)
Research Triangle Park, NC 27711
George Bottoms
Forest Preserve District of DuPage County
881 West St. Charles Road
Lombard, IL 60148
Tom Bowling
Browning Ferris Industries
P.O. Box 3151
Houston, TX 77001
Jim Brede
Diamond Shamrock Construction
River Road
Delaware City, Delaware 19706
Donald P. Brown
Battelle-Columbus Laboratories
505 King Avenue
Columbus, OH 43229
Joe A. Brown
Oklahoma City/County Health Department
921 NE 23rd
Oklahoma City, OK
Bernard G. Browning
City of Fulton, Missouri
City Hall
Fulton, MO 65251
Howard W. Brown!ee
Kaiser Aluminum & Chemical Corporation
Ravenswood Works
P.O. Box 98
Ravenswood, WV 26164
Marion A. Buercklin
Sun Company-Environmental Affairs
P.O. Box 2039
Tulsa, OK 74102
David R. Buss
University of Toledo
2245 University Hills #107
Toledo, OH 43606
Orwin W. Caddy
Gannett Fleming Cordry & Carpenter
P.O. Box 1963
Harrisburg, PA 17105
Edward Cardwell
Greeley and Hansen
222 South Riverside Plaza
Chicago, IL 60606
Evelyn L. Carlson
Becher-Hoppe Engineers
1130 Grand Avenue
Schofield, WI 54476
Paul Cassillo
City of Schenectady
Dept. Eng and Public Works
City Hall - Room 205
Schenectady, NY 12305
Mike Cherniak
Chemical Waste Management, Inc.
P.O. Box 214
Calumet City, IL 60409
Bill Child
Illinois Environmental Protection Agency
33 South Stolp Avenue
Aurora, IL 60506
Howard 0. Chinn
Attorney General's Office
188 West Randolph Street
Chicago, IL 60601
Thomas P. Clark
Illinois EPA - Land Pollution Control
2200 Churchill Road
Springfield, IL 62704
Henry M. Cole
City of Springfield
436 Rosewood
Republic, MO 65804
J. Ron Condray
Monsanto Company
800 North Lindbergh Blvd.
St. Louis, MO 63116
John E. Connors
Eder, Halo, Connors and Associates
85 Forest Avenue
Locust Valley, NY 11560
280
-------
Charles M. Cooley, Jr.
Gregory-Grace and Associates
P.O. Box 34326
Bartlerr, TN 38134
Jack W. Cormack
Greeley and Hansen
222 South Riverside Place
Chicago, IL 60606
James J. Cowhey
Land and Lakes Company
123 North Northwest Highway
Park Ridge, IL 60068
Marie N. Cowhey
Land and Lakes Company
123 North Northwest Highway
Park Ridge, IL 60068
Donald Cowley
Arbuckle Regional Develop. Auth.
319 East Main Street
Davis, OK 73030
W. Alex Cross
City of Winnipeg
280 Williams Avenue
Winnipeg, Manitoba, CANADA
R3B OR!
Henry Cruse
Jacobs Engineering
837 South Fair Oaks
Pasadena, CA 91105
Arthur A. Daniels
John Sexton Contractors
900 Jorie Boulevard
Oak Brook, IL 60521
Jeff Dauphin
West Mich, Environ. Action Council
1324 Lake Drive SE
Grand Rapids, MI 49506
Frank M. Dickinson
Stearns and Wheler
5 Burton Street
Cazenovia, NY 13035
Dwayne Dobbs
City of Odessa Texas
P.O. Box 4398
Odessa, TX 79760
John D. Doyle
Missouri Dept. of Natural Resources
P.O. Box 1368
Jefferson City, MO 65101
James F. Duffield
Duffield Associates
39 Lynn Drive
Newark, Delaware 19711
James W. Dunbar
Georgia EPA
3537 Stanford Circle
Decatur, Georgia 30034
Floyd G. Durham
Arkansas Dept. of Pollution Control
901 Koehler Avenue
North Little Rock, Arkansas 72116
Robert H. Dyer
Gulf Coast Waste Disposal Authority
910 Bay Area Boulevard
Houston, TX 77058
Fritz Easterberg
PII of Colorado
P.O. Box 21186
Denver, CO 80221
David W. Eckhoff
University of Utah
Civil Engineering Department
Salt Lake City, Utah 84112
Roy Eckrose
City of Janesville
18 North Jackson
Janesville, WI 53545
Grover H. Emrich
A. W. Martin Associates, Inc.
900 West Valley Forge Road
King of Prussia, PA 19406
Jack B. Enger
St. Louis Sewer District
2000 Hampton Avenue
St. Louis, MO 63139
Edward E. Everett
Keck Consulting Services
6615 West Bancroft St. #711
Toledo, OH 43615
Dennis G. Fenn
Wehran Engineering
666 East Main Street
Middletown, NY 10940
Richard Fernandez
Briley, Wild and Associates
6 River Ridge
Ormond Beach, Florida 32074
281
-------
Don R. Fielding
Charles W. Greengard Assoc.
1374 Old Skokie Road
Highland Park, IL 60035
Sidney S. Fitzgerald
SCA Services
901 Silver Hill Road
North Little Rock, Arkansas
72118
Joseph A. Fitzpatrick
Northwestern University
Department of Civil Engineering
Evanston, IL 60201
Richard B. Fling
The Aerospace Corporation
2805 Vista Mesa Drive
Rancho Palos Verdes, CA 90274
Karl L. Freese
Horner & Shifrin
3200 Oakland Avenue
St. Louis, MO 63110
Allen Geswein
US EPA
401 "M" Street SW
Washington, DC 20460
Todd Giddings
140 W. Faimount Avenue
State College, PA 16801
Alice Giles
EPA
2911 Dover Lane #101
Falls Church, VA 22042
Michael W. Gilmore
Resources Management Associates Inc.
7300 N. Ritchie Highway
Glen Burnie, MD 21061
Charles N. Goddard
New York State Dept. Env. Cons.
607 Pearse Road
Schenectady, NY 12309
John Goetz
Kansas Dept. of Health & Environment
Topeka, KS 66620
Eugene A. Glysson
University of'Michigan
Civil Engineering Department
Ann Arbor, Michigan 48109
Darrell E. Griffin
City of Springfield, Missouri
1433 East Downing
Springfield, MO 65804
Richard D. Groseclose
3665 Maline Avenue
Neosho, MO 63121
A. B. Gureghian
Princeton University
Civil Engineering Department
Princeton, NJ 08540
William L. Hahn
American Coccoid Company
5100 Suffield Court
Skokie, IL 60076
Richard H. Hall
Procter and Gamble
Winton Hill Technical Center
Cincinnati, OH 45239
Robert K. Ham
University of Wisconsin-Madison
1510 Drake Street
Madison, WI 53211
William R. Hancuff
James M. Montgomery
11800 Sunrise Valley Drive
Reston, VA 22091
Tom Handyside
Handyside, Mannik, Schneider
101 East Dunlap
Northville, MI 48167
Jimmie D. Hankins
Commonwealth of Kentucky
Treasury Department
Capitol Annex - 1st Floor
Frankfort, KN 40601
Lucian A. Harris
City of Alton
City Comptroller
City Hall
Alton, IL 62002
Kenneth S. Hartberger
SCA Services
401 Madison Avenue
Madison, IL 62060
282
-------
Frank Hazelrigg
City of Fulton
Fulton City Hall
Fulton, MO 65251
John E. Heer, Or.
University of Louisville
2212 Wendell Avenue
Louisville, KY 40205
Don Hensch
Oklahoma State Health Department
3005 North Tulsa Drive
Oklahoma City, OK 73107
Doug Hermann
State of Wisconsin
540 Lambeau
Green Bay, WI 54303
Earl F. Holtgraewe
Missouri Dept. Natural Resources
491 Friedens Road
St. Charles, MO 63301
David R. Horn
City of Alton
City Comptroller
City Hall
Alton, IL 62002
Don Hutton
Kerr-McGee Refining Corp.
P.O. Box 25861
Oklahoma City, OK 73125
Cecil Iglehart
SCA Services
8806 Nottingham Parkway
Louisville, KY 40222
I. L. James
Charles Equipment Company
3100 Gravois
St. Louis, MO 63118
Virgil W. Jansen
Barttelbort Rhutasel
#1 Sunset Drive
Freeburg, IL 62243
and Associates
Dennis J. Johnson
John Sexton Contractors Company
900 Jorie Boulevard
Oak Brook, IL 60521
Sandra L. Johnson
Arthur D. Little,
20 Acorn Park
Cambridge, MA
Inc.
Larry D. Jones
Springfield Relay Systems
2565 South Nettleton
Springfield, MO 65807
Robert C. Jones
Floyd G. Browne and Associates
10 Park Court
Napoleon, OH 43545
Lambit. Kald
Leonard S. Wegman Co.
101 Park Avenue
New York, NY
M. Rodney Kimbro
Texas Water Quality Board
Box 13246 Capitol Station
Austin, TX 78711
Jatnes A. Kipp
Iowa State University
8169 Buchanan Hall
Ames, Iowa 50010
Henry A. Koch
Warzyn Engineering, Inc.
1409 Emil Street
Madison, WI 53715
I. Kulnieks
Province of Ontario
135 St. Clair Avenue West
Toronto, Ontario, CANADA
Subodh Kumar
University of Arkansas
2109 Romine Road
Little Rock, AR 72205
Bruce K. Lane
Louisville and Jefferson County
Department of Public Health
P.O. Box 1704
Louisville, KY 40201
Robert Larsen
Wri.ght, Pierce, Barnes & Wyman
99 Main Street
Topsham, ME 04086
Ronald L. Lavigne
University of Massachusetts
West Road
Petersham, MA 01366
Michael P. Lawlor
Browning-Ferris Industries
P.O. Box 3151
Houston, TX 77001
283
-------
Pat Lay
City of Oklahoma City
2121 Westwood Boulevard
Oklahoma City, OK 73108
Arthur G. Lazarus
CE McGuire, Inc.
31 .Canal Street
Providence, RI 20903
Felix C. Lee
City of Commerce City
6015 Forest Drive
Commerce City, Colorado 80022
Michael J. Lefebvre
Foth & Van Dyke and Assoc.
P.O. Box 3000
Green Bay, WI 54303
Gary L. LeRoy
Dept. of Natural Resources
Route 2, Box 250
Spooner, WI 54801
Charles Linn
Kansas Dept. of Health & Environment
Topeka, KS 66620
Ralph W. Luhowy
Regional Municipality of Waterloo
8 Bridge Street East
Kitchener, Ontario N2K 1J2 CANADA
Albert W. Madora
New Castle County
139 Woodshade Drive
Woodshade, DE 19702
Peter F. Mattel
St. Louis Sewer District
2000 Hampton Avenue
St. Louis, MO 63139
Daniel J. McCable
Environmental Enterprises
9054 Revere Run
West Chester, OH 45069
L. L. McCarthy
Tracer Marksman
6500 Tracer Lane
Austin, TX 78721
Harold E. McC.une
Armco Steel Corporation
P.O. Box 600
Middletown, OH 45043
J. N. McGuire
Monsanto Company
800 North Lindbergh Blvd
St. Louis, MO 63166
Gerry McKenna
Ministry of Environment
736 Iroquois Drive
Cornwall, Ontario, CANADA K6H 5C5
Chi!ton McLaughlin
US EPA
8654 Woodson
Overland Park, KN 66208
William G. McLaughlin
XENTEX, Inc.
8607 Quivira Road
Lenexa, KN 66215
Philip G. Mai one
U.S. Army Corps of Engineers
Waterway Experiment Station
Vicksburg, MS 39180
Tom Meientry
SCA Services
99 High Street
Boston, MA 02110
Ken Mensing
Illinois EPA
115A West Main Street
Collinsville, IL 62234
Clayton Miller, Jr.
South WV Regional Health Council
Route 2, Box 382
Bluefield, WV 24701
Jeffrey R. Miller
Wisconsin Dept. Natural Resources
1300 West Clairmont
Eau Claire, WI
Gary Milton
Dowel!, Division of Dow Chemical
Box 1183
Greensburg, PA 15601
H. Clifford Mitchell
St. Louis County Health
801 South Brentwood Blvd.
Clayton, MO 63105
John D. Molitor
Union Electric Company
P.O. Box 149
1902 Gratiot
St. Louis, MO 63102
284
-------
Edward Monteleone
Hennepin County Dept. Public Works
320 Washington Avenue South
Minneapolis, MI 55343
Dale Montgomery
Illinois EPA
2200 Churchill Road
Springfield, IL 62706
Bobby W. Morrison
Tennessee Dept. Public Health
356 Ash Grove Drive
Nashville, TN 37211
Robert James Motchkavitz
General Development Corp.
1111 South Bayshore Drive
Miami, Florida 33176
Howard 6. Moore
Howard 6. Moore Co., Inc.
2122 South Stewart
Springfield, MO 65804
David E. Murray
Reitz and Jens, Inc.
Ill South Meramec Avenue
St. Louis, MO 63105
Marcel! Nadeau
City of Laval
3 Place Laval
Laval, Quebec, CANADA
Dan Nelson
Daily and Associates, Engineers
P.O. Box 278
Champaign, IL 61820
Robert S. Nelson
Monsanto Company
800 North Lindbergh Blvd.
St. Louis, MO 63166
Murray Nicoll
Beasy, Nicoll Engineering Ltd.
1 Scarlet Road
Halifax, Nova Scotia, CANADA B3M 1K7
Douglas C. Nielsen
Public Service Electric and Gas Co.
90 Miller Road
Kinnelon, NJ 07405
Jeffrey E. Noyes
State of Vermont
4 Grant Street
Burlington, Vermont 05401
Robert F. Olfenbuttel
Solid Resources Res. Engineer - USAF
4804 Sunset Drive
Panama City, Florida 32401
Earle H. 01sen
Michigan Dept. Natural Resources
203 State Office Building
Escanaba, MI 49829
T. J. Padden
U. S. EPA
2007 Freedom Lane
Falls Church, VA 22043
Edward R. Pershe
Whitman and Howard
86 Allan Avenue
Waban, MA 02168
Peter F. Petty
The Dow Chemical Company
622 Building
Midland, MI 48640
Richard Power
SCA Services
99 High Street
Boston, MA 02110
Anne K. Raikos
R & R Contractging and Leasing Co.
One Indiana Square - Suite 2220
Indianapolis, IN 46204
Bernard A. Rains
St. Louis Sewer District
10 East Grand Avenue
St. Louis, MO 63147
V. Ramaiah
Missouri Dept. of Natural Resources
135B Brookdale
Jefferson City, MO 65101
C. R. Rea
C. R. Rea and Associates
3419 North Bales
Kansas City, MO 64117
Frederick C. Rice
Reserve Synthetic Fuels, Inc.
1602 Monrovia Street
Newport Beach, CA 92663
M. D. R. Riddel!
Greeley and Hansen
222 South Riverside Place
Chicago, IL 60606
285
-------
P. <3. Riedesel
R & R Contracting
One Indiana Square - Suite 2220
Indianapolis, IN 46204
Kenneth S. Ritelay
EPA
6214 NW 51st Terrace
Parkville, MO
Rick Roberts Dept. of Natural Resources
P.O. Box 1368
Jefferson City, MO 65101
John A. Robertson
St. Louis County Health Dept.
12142 Nottingham
Bridgeton, MO 63044
William F. Roeder
Montgomery County Solid Waste
3414 Greentree Drive
Falls Church, VA 22041
Franz K. Roemer
Hoeganaes Corporation
River Road and Taylors Lane
Riverton, NJ 08077
Terrence A. Sack
Burgess and Niple, Ltd.
7501 Mentor Avenue
Mentor, OH 44060
Mahendra Sandesara
Chemical Waste Management
P.O. Box 214
Calumet City, IL 60409
Cathleen Schnatterly
1106 Louisiana #1
University of Kansas
Lawrence, KS 66044
Robert F. Schnatterly
City of Odessa Texas
P. 0. Box 4398
Odessa, TX 79760
Edward L. Schneider
Schneider's Disposal Service
706 East 4th Street
Richmond, VA 23224
0. M. Schroy
Monsanto Company
800 North Lindbergh Blvd.
St. Louis, MO 63166
Robert H. Scott
Kent County Dept. Public Works
300 Monroe Avenue NW
Grand Rapids, MI 49504
E. Don Seba
City of Leavenworth Kansas
City Hall, 5th and Shawnee
Leavenworth, KS 66048
Fred Sebesta
Nebraska Dept. Environmental Cont.
Box 94877, State Station
Lincoln, NE 68509
Steven W. Sisk
US EPA
6701 Floyd
Overland Park,
KS 66204
John H. Skinner
US EPA
401 "M" Street SW
Washington, DC 20460
Marion C. Skouby
Layne Western Co., Inc.
500 Oak Street
St. Louis, MO 63119
Carol B. Smith
Iowa State University
3221 Lettie Street
Ames, Iowa 50010
Lloyd L. Spangler
U.S. Army Env. Hygiene Agency
SWMD USAEHA
Aberdeen PG, Maryland 21010
Harry J. Spatz
863 Scattergood Street
Philadelphia, PA 19124
Rainier Stegman
University of Wisconsin-Madison
811 Prospect Place
Madison, WI 53703
Bud Stein
Missouri Dept. Natural Resources
157 Selma
St. Louis, MO 63119
Bernard Stoll
EPA-OSW
4408 Airlle Way
Annandale. VA 22003
286
-------
Gilbert E. Stouffer
Illinois EPA
84 Carefree Drive
Chatham, IL 62629
Robert G. Stewart
Sun Oil Company
Box 1135
Marcus Hook, PA 19061
Orville Stoddard
Colorado Department of Health
4723 East Arkansas Avenue
Denver, CO 80222
Clarence M. Stoffel
Owen Ayres and Associates
R #3, Box 168
Bloomer, WI 54724
0. H. Stohldrier
NL Industries, Titanium Pigments
2622 Baltusrol Drive
St. Louis, MO 63129
Paul Stoller
Leonard S. Wegman Co., Inc.
101 Park Avenue
New York, NY 10017
David H. Stous
Burns & McDonnell
P.O. Box 173
Kansas City, MO 64141
Harry C. Strawn
Missouri Waste Disposal, Inc.
3214 Glen Haven
Springfield, MO 65804
John Taylor
Illinois EPA
2924 Old Jacksonville Road
Springfield, IL 62701
Douglas W. Thompson
U.S. Army Corps of Engineers
Waterways Experiment Station
Vicksburg, MS 39180
Jack W. Thorns
PII of Colorado
P.O. Box 21186
Denver, CO 80221
Gregory L. Tipple
Texas Water Quality Board
Box 13246 Capitol Station
Auston, TX 78711
Frank Tirsch
50 Meadow Street
Amherst, MA 01002
Bob Tonetti
US EPA
401 "M" Street
Washington, DC ' 20460 AW464
Rene VanSomeren
Illinois EPA
4500 South Sixth St. Rd.
Springfield, IL 62706
Peter Vardy
Waste Management, Inc.
900 Jorie Boulevard
Oak Brook, IL 60521
Rod Vlieger
Iowa State Dept. Environmental Quality
847 Main Street
P.O. Box 231
Carlisle, Iowa 50047
R. Thomas Wardlow
City of Hamilton, Ohio
315 Sir Edward Drive
Hamilton, OH 45013
David R. Washburn
Naval Facilities Engineering Comm.
F445 Shetland Way
Westville, NJ 08093
Helen F. Wegweiser
Erie County Solid Waste Authority
RD 2 Oak Plank Road
Cambridge Springs, PA 16403
Tommy B. White
Oklahoma City/County Health
921 NE 23rd
Oklahoma City, OK 73105
Richard J. Wigh
Regional Services Corp.
3320 Woodcrest Court
Columbus, IN 47201
Charles S. Wilson
Truk Away of RI, Inc.
Warwick Industrial Drive
Warwick, RI 02886
Kenneth E. Wilson
Zurheide-Herrmann, Inc.
4333w Clayton Avnenue
St. Louis, MO 63110
287
-------
Jim Yallaly
Delta Engineering Consultants
P.O. Box 126
Cape Girardeau, MO 63701
Hasan Yazicigil
Iowa State University
3176 Buchanan Hall
Ames, Iowa 50013
Roman Zaharchuk
Firestone Tire and Rubber Co.
P.O. Box 699
Pottstown, PA 19464
Katherine Royal
Iowa State University
1012 East Hoffman Avenue
Des Moines, Iowa 50316
288
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing]
1. REPORT NO.
EPA-600/9-77-026
2.
3. RECIPIENT'S ACCESSIONED.
4. TITLE AND SUBTITLE
Management of Gas and Leachate in Landfills
5. REPORT DATE
September 1977 (Issuing Date)
B. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Shankha K. Banerji, Editor
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Civil Engineering
University of Missouri
Columbia, Missouri 65201
10. PROGRAM ELEMENT NO.
1DC618
NO.
804859
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
Symposium March 14-16, 1977
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Robert E. Landreth, Project Officer 513/684-7876; See also EPA-600/9-76-004 - Gas and
Leachate from Landfills; and EPA-600/9-76-015 - Residual Management by Land Disposal
16. ABSTRACT
A research symposium on the mangement of gas and leachate produced from sanitary
landfills was held to disseminate latest research informations on the subject, and
exchange ideas between symposium participants from various parts of the U.S. and
Canada. Topics under discussion included gas and leachate formation, collection,
management and treatment. The papers contained in this symposium presents the Solid
and Hazardous Waste Research Division, Municipal Environmental Research Laboratory,
research on sanitary landfills. Selected papers from other organizations were
included to identify closely related work.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Gases, Leaching, Collection, Refuse, Dispo-
sal, Soils, Ground Water, Pollution, Waste
Treatment, Methane, Linings.
Solid waste management,
Sanitary landfills,
Leachate
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
. 297
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
289
U. S. GOVERNMENT PRINTING OFFICE: 1977-757-056/6532 Region No. 5- 1 1
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U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Technical Information Staff
Cincinnati, Ohio 45268
OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE, S30O
AN EQUAL OPPORTUNITY EMPLOYER
POSTAGE AND FEES PAID
U.S. ENVIRONMENTAL PROTECTION AGENCY
EPA-335
Special Fourth-C lass Rate
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