SW-22P
WASTE MANAGEMENT
TECHNOLOGY
and
RESOURCE & ENERGY
RECOVERY
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PROCEEDINGS
OF THE FIFTH NATIONAL CONGRESS
WASTE MANAGEMENT
TECHNOLOGY
and
RESOURCE fi ENERGY
RECOVERY
Cosponsored by the National Solid Wastes Management Association
and the U.S. Environmental Protection Agency
Dallas, December 7-9, 1976
230
ago, Illinois L-J
U.S. ENVIRONMENTAL PROTECTION AGENCY
1977
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U,3.
An environmental protection publication (SW-22p) in the solid waste management series.
For sale by the Superintendent of Documents, U. S. Government Printing Office
Washington, D.C. 20402
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FOREWORD
The U.S. Environmental Protection Agency and the National Solid Wastes
Management Association's Institute of Waste Technology and Waste Equipment
Manufacturers' Institute co-sponsored the Fifth National Congress on Waste
Management Technology and Resource and Energy Recovery in Dallas, Texas, on
December 7-9, 1976.
These technical and planning-oriented Congresses have served to advance
the awareness of developing technologies and practices and to facilitate
their utilization. This Fifth Congress gave particular attention to the
three major areas of solid waste management: hazardous and chemical wastes,
land disposal and resource recovery. Careful assessment of operating ex-
perience in these areas was featured on the program.
The meeting included participants from State and local, as well as the
Federal government, waste management and resource recovery firms, universities,
research and development companies and the financial community. The wide
range of viewpoints included in this volume proved a valuable store of current
information and opinion on vital areas of interest in the solid waste manage-
ment field.
We acknowledge the leadership of NSWMA's Institute of Waste Technology
and Waste Equipment Manufacturers' Institute in organizing these discussions.
Special acknowledgement is due to Peter Vardy, Vice President, Environmental
Management-Technical Services, Waste Management, Inc. who served as Chairman
of the NSWMA Institute of Waste Technology and Glenn Park, Vice President-
Director of Engineering, Peabody Solid Wastes Management, and Chairman of the
NSWMA Waste Equipment Manufacturers' Institute. Recognition is also deserved
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.ollowing organizations which lent their support to this conference:
American Public Works Association
American Society of Mechanical Engineers
Association of State and Territorial Solid Waste Management Officials
National Association of Counties
National Association of Regional Councils
National League of Cities/11.S. Conference of Mayors
Sheldon Meyers
Deputy Assistant Administrator for
Solid Waste Management
Eugene J. Wingerter
Executive Director
National Solid Wastes Management Association
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TABLE OF CONTENTS
OPENING GENERAL REMARKS PAGE
STATEMENT OF MEETING PURPOSE
Wayne D. Trewhitt
TO WHAT EXTENT IS FEDERAL DIRECTION AND REGULATION NEEDED?
Sheldon Meyers
FORECAST OF FUTURE TRENDS FOR LAND DISPOSAL AND RECOVERY OF WASTES
James R. Greco
RESOURCE RECOVERY AND WASTE PROCESSING
MARKETING THE OUTPUTS - ENERGY, FUELS, MATERIALS
Harvey W. Gershman
PROCUREMENT - WHAT ARE THE ESSENTIAL CONSIDERATIONS?
Robert A. Lowe
THE FINANCE-ABILITY AND THE FINANCING OPTIONS FOR RESOURCE RECOVERY
Robert H. Aldrich
Charles A. Ballard
RECOVERING ENERGY ON-SITE - THE EMERGING ROLE OF MODULAR INCINERATOR-HEAT
RECOVERY SYSTEMS
Ross E. Hofmann
EXPLOSION PROTECTION IN REFUSE SHREDDING
Dr. Robert G. Zalosh
WHAT ABOUT THE USE OF SUPPLEMENTAL FUELS?
Stephen A. Lingle
PITFALLS IN PLANNING - THE ENERGY PURCHASER'S STANDPOINT
Alden H. Howard
SOURCE REDUCTION AND SEPARATION - IMPACT ON RECOVERY FACILITIES
Dr. John Skinner
REGIONALIZATION - ITS ROLE IN RESOURCE RECOVERY
Stephen G. Lewis
SOUTH CHARLESTON, WEST VIRGINIA - IN-DEPTH CASE STUDY
Joseph Riyero
SAUGUS OPERATIONAL EXPERIENCE
John Kehoe, Jr
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PAGE
FEATURED ADDRESS
INDUSTRY'S COMMITMENT TO TECHNOLOGY AND SERVICES
Peter Vardy
LANDFILL AND CHEMICAL WASTE DISPOSAL
CHEMICAL WASTE LANDFILL DEMONSTRATION: THE MINNESOTA EXPERIENCE
Robert A. Silvagni
GROUNDWATER PROTECTION SYSTEMS
John R. Reinhardt
HAZARDOUS WASTE REGULATORY POLICY ALTERNATIVES
John P. Lehman
Rosalie Grasso
Dr. Harvey F. Collins
WHAT IS THE ROLE OF 208 REGIONAL PLANNING ORGANIZATIONS IN SOLID WASTE
MANAGEMENT
Robert A. Colonna
Maryann Dean
LINERS - VIABLE OPTIONS AND THEIR APPLICATIONS
Dr. Henry E. Haxo
THE IMPORTANCE OF SOIL ATTENUATION FOR LEACHATE CONTROL
Dr. Wallace Fuller
THE APPLICATION OF SLUDGE TO LAND
Dr. Eliot Epstein
Dr. James F. Parr
THE DILEMMA OF LIABILITY AND PERPETUAL CARE ISSUES
Michael J. Shannon
John G. Pacey
THE ECONOMICS OF LANDFILLING AND PROCESSING - TODAY AND TOMORROW
John Thompson
GROUNDWATER PROTECTION ISSUES
Eugene A. Glysson
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PAGE
EFFECTIVE STATE PROGRAMS
THE IMPORTANCE OF AN EFFECTIVE STATE SOLID WASTE MANAGEMENT PROGRAM
William G. Bentley
GOVERNMENT RESOURCE RECOVERY PLANS
RHODE ISLAND SOLID WASTE MANAGEMENT CORPORATION
Lou David
MIDDLESEX COUNTY, NEW JERSEY
Theodore O'Neil and Garrett Smith.
CITY OF RICHMOND, VIRGINIA
Michael Fiore, P.E
APPENDICES
NSWMA INSTITUTE OF WASTE TECHNOLOGY
NSWMA WASTE EQUIPMENT MANUFACTURERS' INSTITUTE.
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OPENING GENERAL REMARKS
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"Opening General Session Remarks"
by
Wayne D. Trewhitt
Vice President - Secretary
Easley and Brassy Corporation
and
Chairman
NSWMA Institute of Waste Technology
Certainly this Fifth National Congress on Waste Management Technology and
Resource and Energy Recovery promises to be as revealing and challenging
as the previous four. And again we are pleased to acknowledge the co-sponsors
of these conferences -- the U.S. Environmental Protection Agency's Office of
Solid Waste (formerly Office of Solid Waste Management Programs) and the
National Solid Wastes Management Association's Waste Equipment Manufacturers'
Institute and Institute of Waste Technology. Additionally, thank you's go to
the following associations who have lent their support to this important conference:
American Public Works Association Institute of Solid Waste
American Society of Mechanical Engineers
Association of State and Territorial Solid Waste Management Officials
National Association of Counties
National Association of Regional Councils
National League of Cities/U.S. Conference of Mayors
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With the support of fine organizations such as these, this Conference truly
reflects the broadest possible perspective on the key issues in a candid and
forthright manner - to that end this Congress is directed.
As you are likely aware, the focus of this year's Congress is upon resource
recovery, waste processing, landfill ing and hazardous waste disposal. Two con-
current forums are planned -- mini-conferences if you will -- each including
four sessions - 2 of which are technically-oriented, 2 which are management-
oriented. Fewer speakers this year are identified, so as to allow more in-depth
presentations, thorough critique and amplification by expert panelists, and ample
opportunity for audience participation. For those of you who were in attendance
at the Fourth National Congress, you may recall that the audience dialogue often
provided the most stimulating, controversial, and provocative discussions. We
encourage that response at the sessions this year.
At the Business Luncheon planned for this afternoon from 1:00 to 2:30 p.m. in
the Conquistador Room 1 and 2, Peter Vardy, Vice President of Environmental
Management, Waste Management, Inc. and Chairman of NSWMA's Institute of Waste
Technology will deliver an address in behalf of the Institute and what we have
witnessed over the past 2 years.
Most notably at this Congress and following it, we should all strive for
cooperative understanding and reasonable implementation of the newly enacted
"Resource Conservation and Recovery Act of 1976". This Act is likely to be
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often referenced and much discussed throuqhout the next two days. To fully
convey the purpose and likely impact of the Act we are pleased to have Mr.
Phil Cummings, Staff Counsel, Senate Public Works Commitee, and Mr. Sheldon
Meyers, Deputy Assistant Administrator, U.S. EPA with us. Mr. Cummings who
played an instrumental role in assuring passage of the Act will be featured
as our Luncheon Speaker on Thursday. Mr. Meyers, who this past summer assumed
the duties of the Deputy Assistant Administrator's position. He will speak on
the topic "To What Extent Is Federal Direction and Regulation Necessary?".
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THE RESOURCE CONSERVATION AND RECOVERY ACT OF 1976— EVERYBODY'S BUSINESS
Sheldon Meyers*
Good Morning. I am pleased to be here and to have this opportunity
to participate in the opening session of the Fifth National Congress on
Waste Management Technology and Resource and Energy Recovery. My
assigned task this morning—which was, of course, formulated many weeks
ago—is to answer the question: "To what extent is Federal direction or
regulation needed?" On the 21st of October, when the Resource Conservation
and Recovery Act of 1976 was signed into law, the answer to this question
was provided to all of us. I heard the answer loud and clear and applaud
it with vigor.
The Resource Conservation and Recovery Act of 1976 is without doubt
one of those kinds of laws which political scientists cite as evidence
that the system works. That is to say, it is among those laws which are
truly reflective of the will of active public opinion on a given topic at
a given historical moment. Built on the foundation of the Solid Waste
Disposal Act of 1965 and the Resource Recovery Act of 1970 the Resource
Conservation and Recovery Act of 1976 is the evolutionary product of
several years of deliberations and hearings held by a number of committees
of both houses of the Congress. Whether you fully agree with it or not,
Whether or not you think that it emphasizes one facet of solid waste
*Deputy Assistant Administrator, Office of Solid Waste, 'J.S.
Environmental Protection Agency. Presented at the Fifth National
Congress on Waste Management Technology and Resource and Energy Recovery,
December 8, 1976, Dallas, Texas.
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management too much and another too little, you cannot deny that the
Congress did its work well. The Act addresses the complete spectrum of
problems and opportunities which are so intrinsically a part of the
solid waste management issue. It reflects a full awareness of those
areas where we have a high level of technical understanding and knowledge
as well as those areas of technical uncertainty and relates both to the
social and economic ramifications of improved practice.
The Act reflects the fact that all levels of government, industry
and a variety of environmental and other public interest groups had full
opportunity to be heard. It is no wonder then that both houses of
Congress passed it by overwhelming votes.
RCRA integrates the primary thrusts of the two earlier solid waste
acts. It acknowledges the interrelation of the resource-use and public
health issues associated with land disposal. It mandates a series of
actions, requiring effort on the part of all levels of government,
industry and the public—over time—to insure that progress in protecting
health and the environment will not be inhibited by a failure to move
forward in the areas of resource conservation and recovery.
Make no mistake about it. The Congress had a difficult job on its
hands. A long hard look at the status of solid waste management reveals
that this issue touches the very frontiers of our society's movement
toward environmental responsibility. How we deal with solid waste
influences, and is, in turn, influenced by, far-reaching social and
economic issues. These range from the attitudes of the individual
citizen and consumer, through how we extract, manufacture and market
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products, to such complex issues as dep-etion allowances ana international
trade policies. It is no wonder tnat it took a while and that the Act
does not provide immediate, ready-made solutions to all the varied
problems and perplexities we have been debating for so many years.
Instead, the Act calls for new patterns of interaction among all levels
of government, the assumption of key responsibilities by industry on
several fronts, and for meaningful public understanding and participation
in all the major activities mandated by the Act.
In my opinion, this is as it should be. Particularly if we examine
the Resource Conservation and Recovery Act of 1976 in light of the
recently passed Toxic Substances Act and the Safe Drinking Water Act it
becomes apparent that the Congress is reflecting a new dimension in
public understanding of what is required to improve the environment.
Tn^s iew understanding goes far beyond the relatively simplistic attitudes
so popular a decade ago, when many seemed to think that placing stoppers
on air polluting stacks and water polluting outfall pipes was all that
was needed to save us from burgeoning environmental problems we had
neglected during cwo centuries of technological and economic achievement.
Those of us in this room are bound to see this new law, most of the
time, from a perspective that narrowly reflects each person's particular
area of expertise and interest. This is inevitable. Nevertheless, it
is essential that we all draw back from time to time and attempt to see
it whole, with all of its many provisions in focus, from the small end
of the telescope. That, of course, is what I am doing this morning.
Viewed from such a perspective, I think we can speculate with some
degree of certainty on the law's essential meaning. It means that our
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country is now ready to face the fact that the land is a natural medium
which needs to be protected just as air and water do and that resource
conservation and recovery are a key element in the process of achieving
environmental quality.
The sink of last resort is going to disappear as an inexpensive
option for hiding our mistakes and in its place environmentally sound
procedures for dealing with wastes will emerge. I believe that all the
provisions of the Act are supportive of this goal within which, by no
means our only, but certainly our most urgent, necessity is to move
rapidly toward controlling the most obviously undesirable portions of
the waste stream. Hence, the special, urgent and necessary emphasis 011
all aspects of hazardous wastes management.
Subtitle C of the new law brings management of hazardous wastes
under Federal-State regulatory control. Hazardous waste is defined in
the Act as any waste that "because of its quantity, concentration, or
physical, chemical, or infectious characteristics" may seriously threaten
public health or the environment. EPA is required to identify these
wastes, set standards for their management from cradle to grave and
issue guidelines for State programs over the next year and a half. The
standards go into effect 6 months after their promulgation. States are
to establish hazardous waste control programs that will meet Federal
requirements and issue permits for treatment, storage, and disposal of
such wastes. In those States which choose not to do so, Federal
regulations will apply. Civil and criminal penalities are established
for noncompliance. To assist States in developing and implementing a
hazardous waste program, $25 million in grants is authorized to be
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appropriated for each of fiscal years '78 and '79. Please note that we
do not yet have appropriations under the new law, and therefore do not
yet know what sums will actually be available for implementation of the
hazardous waste or other provisions of RCRA which require funding.
The new law will increase financial and technical assistance to
State, regional, and local agencies for the development of comprehensive
programs of environmentally sound disposal, resource recovery, and
resource conservation. "Resource conservation" is defined in the Act as
"reduction of the amounts of solid waste that are generated, reduction
of overall resource consumption, and utilization of recovered resources."
EPA will issue guidelines for State solid waste plans. To facilitate
regional planning, EPA guidelines will also be issued for identifying
regional areas with common solid waste problems. The amount of Federal
funds authorized for grants to States for developing and implementing
State and regional plans is $30 million for fiscal '78 and $40 million
for fiscal '79. In addition, $15 million is authorized for each of those
years for grants to regional and local agencies as well as States to
implement specific programs that fall within approved State plans.
For a State to be eligible for these grants, its solid waste plan
must mee* minimum criteria. Among them is inclusion of a requirement
that all solid waste be utilized for resource recovery, disposed of in a
sanitary landfill, or disposed of in some other environmentally sound
manner. The plan must also provide for the closing or upgrading of all
existing open dumps.
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Criteria for identifying open dumps and for identifying sanitary
landfills will be published by EPA no later than October 1977, and the
Agency will conduct a national inventory of all open dumps within the ]2
months that follow. The Act mandates that all open dumps throughout the
country must be closed or upgraded by 1983 and forbids the creation of
new dumps. Special grant assistance to help meet these new requirements
for land disposal facilities will be available for rural communities.
Twenty-five million dollars for FY 78 and 79 is authorized for assistance
to rural areas.
Grants to a limited number of "special communities" are also
authorized. These are to be communities of less than 25,000 population,
most of whose solid waste comes from outside their boundaries, causing
serious environmental problems.
Recognizing that States and many local governments will face very
difficult problems in meeting the goals and requirements of this legislation,
the Act provides for technical assistance teams, called "Resource Recovery
and Conservation Panels," which will be available to State and local
governments on request. The teams will be prepared to assist in upgrading
collection and disposal as well as in developing resource recovery and
resource conservation systems. We expect to field these teams from our
Regional Offices, where they can gain familiarity with conditions in
specific geographic areas.
Wide general authority is conferred by the law for studies, research
and development, demonstrations, training, and information activities.
The authorization for these functions total $45 million for fiscal "78.
The. objective is to strengthen and increase the technological base,
available expertise, and public understanding that must underlie State
and local programs in order for them to succeed.
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Demonstrations in resource recovery and improved solid waste disposal
facilities are authorized. Studies are required in many specific areas,
including sludge management, source separation, agricultural and mining
wastes, actions to reduce waste generation, collection methods, incentives
for recycling, the imposition of disposal charges on products, and the
problems of acquiring land for solid waste management facilities.
In the task of building up the technology for solid waste management,
we in the Office of Solid Waste will continue to share responsibility
with EPA's Office of Research and Development. In the energy recovery
projects, EPA and the Energy Research and Development Administration are
required to work out cooperative arrangements.' The commercialization of
proven resource recovery technology is assigned by the Act to the Department
of Commerce.
A large-scale study of resource conservation will be undertaken
by an interagency committee headed by the EPA Administrator. The study
will cover the effects of current public policies on resource use and
the consequences for the environment and society, and the potential
effects of proposed measures, particularly the imposition of disposal
charges on products.
In the provisions for information activities, special emphasis is
placed on rapid dissemination of information, on public education programs,
and a central reference library of solid waste management data and other
materials. Efforts are required not only to inform the public but also
to promote their participation in the development of Federal and State
regulations, guidelines, and programs.
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The authorization for EPA for general administration of the programs
under this Act is $35 million for fiscal '77—more than double last year's
appropriation—$38 million for fiscal '78, and $42 million for fiscal "79.
At least 20 percent of this is to be used for the Resource Conservation
and Recovery Panels I described earlier and at least. 30 percent for
carrying out the hazardous waste program.
There, in a rather large nutshell, are the major provisions of the
law. It is obvious from the nature and number of specified activities
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and the increased authorizations for funding that national perceptions
of solid waste management issues have undergone major changes.
Perhaps of greatest significance is the heightened concern about
threats to health and environment from hazardous wastes and from inadequately
controlled land disposal. This concern has developed from damage incidents,
from investigations of recent years, and from the realization that
pollution controls to protect air, waterways, and oceans are resulting
in rapidly mounting loads of residues destined for the land, a heretofore
largely unprotected medium. The provisions in the Act for Federal regulation
of hazardous wastes and the prohibition of open dumping are the strongest
in the Act, and are unprecedented in Federal legislation in the field
of solid waste management. The Act clearly provides for State administration
and enforcement, with Federal power serving as a necessary backstop
where States fail to act. The provisions for assistance to the States
for developing programs that meet basic standards make that quite clear.
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For the first time, sludges are specifically included in the
definition of solid waste in the legislation. Sewage sludge disposal is
already a perplexing, expensive problem for many cities, and by 1985,
the quantity of sewage sludge generated is expected to double as a
result of improved wastewater treatment. Sludge is prominent among
those wastes which we believe can be put to work to convert a problem
into an environmental asset. Its value as a soil conditioner for non-
food-chain use is widely known. Since some sludges contain heavy metals
and other contaminants, the use of sludge for food crops requires
careful analyses including testing of both the sludge and the soil prior
to application. Identifying safe, economic, and acceptable means of
sludge disposal and utilization is a matter of high priority for EPA.
Sludge management represents only one of many instances in the
field of waste management where, partly in response to environmental
problems of disposal, attention has increasingly turned to means of
utilizing waste as a resource.
Federal assistance for planning and building resource recovery
facilities is available under the Act for State, regional and local
solid waste programs, and as demonstration grants. No large financing
mechanisms or loan guarantee provisions were included in the Act, but in
view of the current level of technology and the unpredictability of
markets for recovered products, the emphasis on regional and statewide
planning and on demonstrations and evaluations at the Federal level is
appropriate. Source separation methods for materials recovery are also
cited for support and study, and though lacking the glamour of the
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large-scale technological systems which depend in large measure on
energy recovery for their economic viability, source separation approaches
may one day be regarded as the most effective means of recovering
materials from the waste stream.
It is noteworthy that waste reduction is clearly recognized in the
Act as part of the continuum of processes that make up sound solid waste
management. One of the specified objectives of Federal assistance to
State and local programs is to encourage resource conservation, and it
is a required subject of studies and information dissemination
activities. Further development of methods and policies in resource
conservation are badly needed. Much of the interest in this area has in
the past been concentrated on packaging but there aie many other issues,
relating to measures of greater and lesser economic scope, that also
must be grappled with. The studies mandated in the Act of public
policies related to resource use, including the concept of placing
disposal charges on products and thereby creating economic incentives to
avoid waste, should contribute substantially to a better understanding
of the directions in which this country should move to promote optimum
resource use.
The new law thus addresses issues in solid waste management that
have relatively recently come to the fore in the public consciousness.
And, as I have already implied, it also carries forward the continuing
emphasis on the State program as a major key to successfully unlocking
the opportunities inherent in waste problems. The provisions of the
new Act for planning and program grants, technical assistance, research
and demonstrations, and information collection and dissemination should all
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serve to enlarge the capabilities of both States and local governments
to fulfill their increased responsibilities.
In the Office of Solid Waste in EPA, we are involved in the complexities
of getting the new Act under way. The nature of RCRA demands the involvement
in our plans and deliberations of other components of EPA. These include,
in addition to air, water, pesticides and toxic substances components,
the Office of Planning and Management, the Offices of General Counsel
and Enforcement, the Office of Regional and Intergovernmental Operations
and several components under the supervision of the Assistant Administrator
for Research and Development. The last mentioned is especially important.
Major unmet needs in this field depend on a variety of research efforts
cited in Subtitle H of the Act.
But of course this is not EPA's Act, it is the public's, and as all
of us have had ample opportunity to learn in recent years, the far-
ranging issues influenced by solid waste management cannot be properly
characterized, let alone resolved, if the only active participants in
the process are those of us who regularly read the technical literature
and have the professional opportunity to attend meetings such as this.
The framers of the Act understood this very well and made it clear that
solid waste is everybody's business. Hence they called for rapid information
dissemination, public education and public participation programs. The
Congress understood that even those represented in the audience today,
who have varied positions and interests and sometimes conflicting views,
are nevertheless an in-group, and that all in-groups tend to reinforce
their own biases,
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I assure you that I intend to take the public information and
public participation requirements of this legislation very seriously
indeed. Our Regional offices will play a major role in this activity,
to ensure full State and local governmental involvement and benefit.
Next week, on December 16, we are holding our first informal Public
Participation Meeting in Washington, to give representatives of major
governmental, industrial, environmental and other organizations the
opportunity to give us their preliminary views, attitudes, and suggestions
on the planning and implementation of the RCRA.
As I implied earlier, the Act takes note of what we know, but just
as certainly of what we don't know. Moreover, since scientific knowledge
by its very nature is always incomplete, public awareness, understanding,
and participation are absolutely essential. Without it, we would have
little chance of defining and regulating hazardous wastes, and even less
of upgrading land disposal overall, phasing out the use of open dumps,
and bringing into existence a new magnitude of activity in the areas of
resource recovery and conservation.
Our field is one in which, until quite recently, few of the practitioners
really thought of themselves as being governed by the same environmental
and public health considerations which have long applied to other environmental
problems, such as air pollution. The new Act makes it clear that this
is an illusion which we must now cast off. Since this is so, I shall
close my remarks today with two quotations from Dr. Leroy E. Burney who
was Surgeon General of the U.S. Public Health Service way back in 1958,
when the first National Conference on Air Pollution was held, three
years after the first Federal Air Pollution Act was passed.
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Dr. Burney said, and I quote:
"In law, the suspect is innocent until his guilt has been
proved beyond reasonable doubt. In the protection of
human health, such absolute proof often comes late. To
wait for it is to invite disaster, or at least to suffer
unnecessarily through long periods of time.
"Many years ago, before anyone had seen a germ, or positively
identified a single causative agent of epidemic diseases, far-
sighted leaders observed the association between epidemics and
filth. Wherever they had sufficient foresight to act on this
circumstantial evidence, they made striking progress. Cleaning
up the city filth resulted in better health. Years later,
they found out why.
"I suggest that our present position with respect
to contemporary problems, especially those relating to
the urban environment, may be parallel to that of
Pasteur's predecessors."
Later on, in that same address, Dr. Burney made another statement which
also seems particularly pertinent to our situation in solid waste management
today. He said, and I quote:
"The problems that come as byproducts of our almost
unbelievable material progress demand everybody's skills
and knowledge. More than that, they demand genuine
cooperation. We can no longer ask, Who's going to be
in charge? or Who's going to get the credit? We must
ask How can we most effectively work together?"
Thank you.
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FORECAST OF FUTURE TRENDS FOR LAND DISPOSAL
AND RECOVERY OF WASTES
James R. Greco
Technical Director
National Solid Wastes Management Association
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Nearly three years ago a market study of the solid waste management field
was conducted by a nationally known market analysis firm. The opening paragraph
of the summary section concluded that:
"The solid waste management program in the United States
will continue to expand during the decade as Federal and
state governments continue to enforce legislation and laws
that have been and will be enacted to improve solid waste
management practices and to recover either useful materials
or energy from the ever-increasing amounts of solid wastes
generated".
Certainly, the intent of the Resource Conservation and Recovery Act of 1976
is to improve solid waste management practices and to encourage expanded re-
covery of useful materials or energy - in addition to the conservation of
valuable material and energy resources and the protection of the environment.
The Protection of the Environment is perhaps the central and most significant
aspect of the new law. It is key to the dual mandate for the prohibition of open
dumping and regulating the storage, transportation, treatment, and disposal of
hazardous wastes. Certainly, the business environment for land disposal and hazardous
waste management will thrive with the promulgation of these provisions - and
resultingly, resource recovery programs, likewise. Whether this scenario will un-
fold, however, is legitimately questionable! One reason being as to whether the
law's mandate will be implemented with sufficient funding authorizations and ap-
propriations. Another reason may be the legal morass that can result because of
the possibility of citizen suits challenging the effectiveness of the regulations.
Nevertheless, let me postulate an example of trends for land disposal and recovery.
By the end of this decade, hazardous wastes will come under a control system. Few
hazardous wastes will be indiscriminantly put into or onto the land. Consequently,
the "pollution potential" of land disposal sites will be lessened, perhaps
dramatically! I believe the prohibition of open dumping will be implemented
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gradually and slowly. Although by law open dumping should be non-existent by
1983, it may not be economically practicable to meet this deadline much sooner
than the early 1980's. Naturally, with the ban on open dumping, more communities
will begin to implement resource recovery programs as feasibility and economic
viability become attainable. How do I feel about "resource recovery'"? I
believe we as an industry have entered a period of "responsible optimism" where
solid waste management/resource recovery systems are more realistically considered.
Perhaps the most revealing fact which has surfaced during the past year is that
resource recovery technology can be part of the solid waste management system
and is also viewed firstly as a disposal option and secondly, but importantly,
a recovery opportunity. As far as the focus for recovery technology - more emphasis
will be placed on materials recovery study, research, and development that was not
anticipated last year. Materials recovery not only for recycling glass and metals
but also on the production of new process materials and feedstocks for manufacturing
processes.
Ironically, the success of the new law and the shape of the future may not be
ultimately determined by the Federal government, State governments, local govern-
ments, or the private sector - but by the general public. The general public has
not seemed to perceive solid waste management. We have failed as an industry
to convey to the citizenry our identity as an "environmentally needed" industry.
We must also act to do so urgently but responsibly - lest we, as an industry
find ourselves in a situation where:
(l) the public focuses on solid waste management problems and A pollution
potential perspective rather than pollution abatement:
(2.)the public delays the commencement of environmentally acceptable
facilities and sites via the permit process;
( ') the public is unwilling to pay the costs of improved solid waste
management practices, environmental protection, resource conservation,
and resource recovery:
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(4) law suits are filed to challenge the regulations and accelerate
the closing of dumps; and
(5) with perhaps a Catch-22 situation arising .
Certainly, we, as responsible governmental officials and private enterprise,
must work intensely to build the environmental protection character of our
industry in the public's mind. Public law 94-580 can be a step in the right
direction and should be.
In the October, 1974 issue of Scouting Magazine, there appeared an article
entitled "There's Gold in Your Garbage". I surmised that the magazine's reader-
ship were youths who must have been amazed when they read about the "gold" in
their garbage. Then I fantasized. Suppose there really was gold in the garbage?
Would not the scouts pick it out and extract the monetary value for themselves
if they recognized the gold in the garbage? But suppose the scouts did not see
this treasure but the refuse collector did. The collector would likely "source
separate" to pull the gold before it was mixed in with the trash, provided that
the householder (scout) would cooperate. But suppose the collector like the
householder failed to perceive that the garbage did contain gold, and the local
government suspected some profit from the community's discards (which may be laden
literally with gold)? To find that gold and realize its value, perhaps a central
plant would be built, mechanized and tuned to pull upon demand the gold from the
otherwise valueless stream. But then again, suppose neither the householder, nor
the collector, nor the local government thought there was gold in their garbage -
or perhaps it was just too difficult to find? Well the gold might then be buried,
hidden in the rubbish, with hopes that some day it will be mined to fruition. But
if that hope diminishes, the scout - with whom this short story began- might deduce
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that it makes no sense to search for gold where none may never exist, and he
may conclude that in the end it makes no sense to handle vast amounts of wastes
when the volumes might somehow be reduced.
The solid waste management industry certainly is experiencing much debate and
discussion as to the alternative and perhaps compatible methods for solid waste
management, resource recovery and resource conservation. However, whatever the
alternative implemented, one must recognize that solid wastes management es-
sentially is a service of need and necessity for the general public. Hence,
the central purpose remains to remove the wastes from where they are generated
to an ultimate disposal site in a manner consistent with the protection of the
general health and welfare of the public in a cost-effective way. Where feasible,
recovery of energy and material resources will serve to complement this purpose
for the betterment of the populace!
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RESOURCE RECOVERY AND WASTE PROCESSING
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MARKETING THE OUTPUTS - ENERGY, FUELS, MATERIALS
By
Harvey W. Gershman, Director
Resource Recovery Division
Urban Services Group, Inc.
Presented at the Fifth National
Congress on Waste Management
Technology and Resource and
Energy Recovery, Dallas, Texas
December 8, 1976
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MARKETING THE OUTPUTS - ENERGY, FUELS MATERIALS
If resource recovery processing is to replace other traditional methods
of solid waste disposal, users for the outputs must be identified and secured.
The success with which users are developed from the start of project design
will be the key to their eventual involvement and the overall economic viability
of any forthcoming project. Discussed here are important considerations for
the planning process from the start, to the point where actual facility pro-
curement begins.
There are three stages in developing the market: the identification stage;
the commitment stage; and, the contractual stage.
Identification Stage
During the first stage, the "Markets Study" is performed. It identifies
what users are available for the various energy and material products that
are possible to be produced by resource recovery technologies.
The first step is to get a handle on what is in your waste stream, since
it constitutes the set of raw materials from which the energy and materials
products will be produced. This need not be done through any large-scale sampling
program, since the effort required and the statistical validity of such work
with respect to the level of accuracy needed at this stage, will most likely
not lead to productive results. Also, there is an increasing data base, both
on a national level and as examples from specific jurisdictions, on
composition of the waste stream. A literature search, looking at such sources
as data from the U.S. Department of the Interior's Bureau of Mines facility and
from the U.S. EPA's Office of Solid Waste, will provide the basis for applying
existing information to your individual circumstances. With this accomplished,
you can then feel the rough level of potential products you have, and don't have.
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Based on this level of knowledge of the waste stream, the approach with
the markets during the identification and commitment stages should be to use
your rough estimates of tonnage output for the products in development of
commitments to accept: either a product tonnage range with minimum and
maximum levels set; or, at least a certain tonnage, with a floor tonnage set
upon your best estimate of the minimum amount of available raw wastes that
could be turned into a product. Refinements can be made to pin down more
precise tonnage levels later on.
The markets investigation should not preclude, a priori, the production
of any available energy or material product. To do this may unnecessarily
limit the scope of investigations and the eventual viability of the implemented
project. Remember—the markets are your disposal mechanism which also play
a key role in the economic success of the project. As such, the recovery project
should be viewed as abridge effectively relating the input wastes (the raw
product) to the end-users in a viable, long-term manner.
The first contact with possible users is made during this stage, a'ld
the dialogue that is developed is important for any future involvement.
Often, and especially for certain energy users, development of an apprecia-
tion for solid-waste-derived products will be a first. Because of this, a
markets education may have to be performed as other background data are
gathered.
For energy product users, the data gathered should include: descrip-
tion of energy production facilities, future energy requirements, types
and amounts of fuels consumed, availability of on-site space, energy demand
curves, value of alternative fuel/energy sources, economics of present energy
production, adaptability of integrating the use of either solid fuels, pyrolysis
rjasi-s, pyrolysis oils, steam and electricity, and overall interest in using
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new energy sources. Energy users identified include: electrical or steam
generating utilities, large industrial facilities, university and hospital
complexes, downtown existing steam/cooling loops, new commercial/industrial
steam-chilled water loops, and so forth.
Also, remember that your goal in development of markets is to structure
a markets situation that can handle all of your projected output of a given
product. This need not be done by one single user. For the energy product,
which represents the largest single product in terms of percentage product
output, it is extremely helpful to secure a single, highly reliable user. The con-
cept of multiple users, however, is worth investigation. We find this con-
cept being used, for instance, in the planned steam-generating facility
for Akron, Ohio. With the increased attention being payed to such technologies
as the small, modular heat recovery system, jurisdictions may be able to
implement such projects as refuse-derived -fuel production (RDF) and use by a
number of small to medium sized users. Particularly for areas with significant,
potential commercial and industrial users with the ability to use relatively
small amounts of a facility's RDF output, c;uch a project may even be more
desirable than going with one large,but insecure, user. In this way, the impact
of eventually losing one user will be lowered.
Once this information is gathered, an evaluation will be required to
determine when one or several installations can provide the required consumption
levels for the different energy outputs. Once the more preferrable users are
identified, future activities should be closely coordinated to ensure a continuing
and active market role in future project planning. Establishing a relationship
with the likely energy users will make future project coordination and develop-
ment much easier.
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This market role should not be underestimated. Various project develop-
ment processes have discovered, in fact, that all potential markets are not
passive ones. In Lynn, Massachusetts, the General Electric facility is
a good example of this. Here, the future energy user took an active role in
the development and implementation of the RESCO project. The help of such
active future users can be very valuable, with proper consideration given to
the specific type and level of involvement they will play.
For materials products, contact is made with likely users for the various
products in the waste stream. These users are often more familiar with the use
of the recovered product in their industry then energy users. For example,
certain industries (e.g., paper, steel, aluminum, glass) have established
specifications for secondary products they are interested in purchasing End
have experience with using similar products in their manufacturing process. For
these reasons, it will be less difficult to assess material product users
Trie uLi.
be on a first-come, first-served basis to those who actually deliver a product,
as "commitments" are often made to several projects.
The result of the general identification will be a "Markets Data Base"
which states who could be looked toward, for which products, at what tonnages,
and for what probably value. With this in hand, it will be possible to decide
what generic type of resource recovery processing should be employed to meet
the specifications set forth as a result of the survey.
Overall, some estimate whould be made of the potential value of
waste-derived products. Generally speaking, the value of the recovered product
is tied to some economic indicator. It may be a quoted value in Iron Age
Magazine for No. 2 Bundles in New York or in the Federal Power Commission's
Monthly Fuel Cost and Quantity bulletin for the cost of a million BTU's in
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Illinois. There are almost as many variations to such a formula as there are
agreements. Additionally, the price set may be simply fixed. The value of
these products per ton of input waste can only be determined by factoring in
the process recovery efficiency, fuel/energy product quality and amount, local
pricing considerations (energy and materials), and transportation costs to bring
the product to the user.
Commitment Stage
With the markets in.mind, a closer look at the processing technologies
available to meet market specification should be made next. This evaluation
will look at technological risk, system capital and operating cost, alternative
facility sites, overall system logistics and cost, financial and management
alternatives, required legislation/authority farming, budget requests, etc.
As this other information is developed, a further refinement of market develop-
ment should ts^'e pV?ce prior to decisi"op on project "*no/no-c;o".
The development of more detailed documents such as "Memoranda of Under-
standing", "Letters of Intent to Bid for the Purchase of Recovered Products",
or actual "Invitation of Bid for P>ecovered Products" should be undertaken.
Such instruments should clearly state terms and conditions that each party
will place on the other during actual sale of the product over a period of
time.
In negotiating prices for energy products*, the guiding principle should
be to establish a fair and equitable price for both the producer and the user.
This price should provide an incentive to produce the fuel as well as use it.
Hence, the price should lie somewhere between the net cost of production and the
net value of the fuel to the user.
Solid, liquid and gaseous fuels, eloc-tricity.
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Determination of these values is the next problem. Tor example, for a
refuse-derived fuel (RDF) product to be used in 'existing boiler installations,
the net cost of production would include: (1) the annual capital investment
cost; (2) annual operating and maintenance costs; and, (3) the marginal
savings/cost of not having to landfill or incinerate that product which
was delivered to the user. Questions remain as to how precise each of these
factors may be calculated. The life span of these systems are extremely
difficult to estimate with a fine degree of accuracy. There is also a problem
of apportionment in applying the operating and maintenance costs of the various
items when there is more than one output.
For the user of an energy product such as RDF, the net value of the fuel
would be the dollar value of the heat content adjusted to account for addi-
tional costs. The expenses would include: the capital cost of auxiliary
equipment for storing, handling and firing the fuel; operating and mainlenance
costs; and, changes in boiler effiency. All these are netted against tie value
of the displaced fuel.
Again, such values cannot be expressed with a great deal of certainty.
If the user is an electric utility, there may be "economic dispatch penalty
costs" associated with the operation of'the boiler designated for RDF use
if it is more economical to operate other types of units. Costs may increase
when newer and more efficient units enter into the utility system after the
utility has installed equipment and contractually obligated itself to accept
RDF. The utility must consider this possibility since it is obligated and
regulated to supply power to the public at the cheapest possible price. This
effect is most pronounced in the case where additional generation capacity flows
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from newly added nuclear power plants. Incremental costs of generation in
these plants are much lower than for those fired by fossil fuels. The success
to negotiating an agreement that is attractive to both parties will occur if
each party does not try to optimize his benefit at the expense of the other.
For an energy product such as steam, the considerations and experiences
are different. Historically, incinerators with steam generating capacities
have not had "out of plant" users. While this trend is definitely being
reversed by energy recovery facilities across the nation, problems remain
to be considered prior to implementing steam energy recovery systems. One
of the problems of. selling steam to commercial users (based on municipal solid
waste as feedstock) is the necessity to vary generation to meet load condi-
tions. In order to do this, a boiler by-pass flue or steam-condensing equip-
ment must be provided. Conversely, when the demand for steam exceeds the supply,
auxiliary fuel-firing systems must be incljded in order to provide an unin-
terrupted supply.
Unlike fuels derived from solid waste, steam produced from solid waste
is indistinguishable from that produced from other energy sources. To be
saleable, this steam must meet the specific needs of the users. When designing
a solid waste disposal/steam recovery system and pricing the resultant energy
product, several factors thus need to be considered. These include:
• proxijnity_ to customers - A steam generating facility must have
a nearby market because steam cannot be transported economi-
cally more than a few miles. In congested areas, expensive
pipeline installation may further restrict this distance.
• value - The cost at which the steam is delivered must be com-
petitive with the cost of the customer's alternative enorgy
sources.
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• quantity - Price is effected by the ability of the steam plant
to supply amounts of steam which are compatible with the cus-
tomer's needs. If supply is guaranteed to the customer and peak
loadings cannot be met entirely by burning refuse alone, then
stand-by fossil fuel-fired boilers will be needed and the price
correspondingly increased.
• operating schedule - The steam producing facility must set up
an operating basis that conforms to the operating schedule of
the steam customer. This effects the price of the steam as
well as the existence of the market itself.
> steam quality - The temperature and pressure at which the steam
is produced must be a function of the limits acceptable to the
customer's steam contract. Variations from this norm could
seriously effect the price of the steam.
» reliability - If service is to be non-interruptable, contin-
gency plans should be made when the solid waste unit is out
of service.
• timing - This aspect can seriously affect the steam plant and
the expected revenues. Unanticipated delays in construction
of the facility could force the steam customer to secure
another source.
Steam can be marketed in two ways: as a guaranteed supply ("unin-
teri'uptable service"), or db a limited supply tnat requires a Back-up
system ("interruptable service"). The pricing structure will vary in
accordance with the type of service offered.
In the first case, the municipality provides a complete and re-
liable supply of steam, and assumes the responsibility of producing
steam from other sources if there should be an interruption in the
production of steam from solid waste. If the municipality is supplying
steam that the customer does not have the capability of producing,
then the municipality must guarantee the reliability of supply. While
the municipality's costs go up, so also does the value of the steam it
is selling. This steam has a value equivalent to what the customer
would have to spend to produce it himself. In the second case, the
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customer buys all the steam the municipality produces from solid waste, and
thereby assumes the burden of producing additional steam in the event that
this supply is interrupted or not adequate to meet his demand. In this case,
the value of the steam is necessarily lower, in that it is limited to the value
of the fuel saved by the customer. At the same time, the municipality assumes
less risk and responsibility.
The price of steam delivered to the industrial user is therefore a
matter of "marginal cost" vs. "true replacement cost". Fuel shortages and
dislocations as well as rapidly rising prices for fossil fuels should accen-
tuate a trend toward the marketability of a reliable steam supply.
For materials products, the "commitment" document should include terms
and conditions with respect to floor prices and exchange price formulas, length
of commitment, quantity, quality, delivery schedule, and termination provisions.
The longer the period over which material would be pruchased, the better.
Five-year periods are often specified, especially in "Letters of Intent." This is
adequate, although a ten-year period would be preferrable, since it would be
more representative of a project's amortization and operational lifespan.
In general, the decisions on implementing energy and/or materials recovery
will follow a few overall guidelines. Not every facility will choose to
implement both energy and materials recovery, regardless of the technological
development situation. Both, however, are tied to the availability of
markets -- without them, the production of the given energy or materials
will be meaningless. Somewhere during the "identification" and "commitment"
stages, an initial decision must be made on which products to produce. The
decision on energy production will be most directly tied to the existing or
near-future disposal crisis, since the energy raw materials represent the largest
percentage of the waste stream, and also the preponderence of the biodegradable
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material. Also crucial here are the economic questions of production costs
versus energy revenues and disposal credits. With the materials products,
however, the economic questions take priority, since any disposal crisis
will not be significantly improved by materials recovery.
Contractual Stage
During the "contractual" stage, the "commitment" agreements, which served
to solidify the project for purposes of budgetary planning, council approval,,
etc., need to be made into hard and fast agreements clearly stating all the
terms and conditions that will be promulgated into actual purchase orders or
purchase agreements. Having such contracts will provide the basis for making
the project financable, especially if some sort of bonding mechanism, es-
pecially revenue bonding, is to be employed for the intended project. The
"contractual" stage is the stage at which signatures are placed on the 'bottom
lino'. Other key matters must be also made to happen prior* to this finalizaticp,
and confirmation of the marketplace. These include the successful implementa-
tion of a "Request for Proposals", in the case of a facility to be privately
operated, to the preparation of budget requests and general bond authorizations
in the case of a publicly owned/financed facility. In order to get to this
stage, other factors including site, management, risks, technology, waste
control, etc. will also have to be decided.
From the supplier's point of view, the primary concern of a solid waste
processing facility is its ability to dispose of the waste. The
establishment of long-term contracts assures the operator of a steady outlet
for the recovered products without the need for stockpiling large amounts.
Further, long-term contracts avoid dependence on spot markets which are sensitive
to local supply and demand factors which can fluctuate widely. The possibility
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of higher revenues from spot markets whould be sacrificed in order to obtain
a guaranteed outlet for the recovered product. As a result, additional over-
head costs for storage can be avoided. The long-term market, with a specified
floor price, also can provide a basis for the insured revenues necessary to estab-
lish the financial foundation for a resource recovery facility.
For the purchaser of the recovered materials, the long-term contract
guarantees a steady supply of raw materials at a reasonable price. This also
ensures continuous processing. Thus, the buyer can justify a required capital
investment in additional handling equipment and the other items necessary to
introduce the recovered products into the manufacturing process.
•Finalization of signed user contracts will only take place if the user is
convinced that the intended project will produce products according to their
required specifications. If there is uncertainty in the ability of a process
to produce the required output specification, one of two things will occur.
The first is that the user will end any negotiations. Secondly, they may still
sign for the product, well knowing that start-up period will prove whether or
not the facility can meet specifications.
In making contacts with potential buyers, the assumption should be made
that purchase orders for the sale of recovered products will go out for bid.
This approach, however, often prevents the potential user from offering his
best price, since he knows that any signed "Letter of Intent" will become public
information and may serve as a minimum target for other bidders. Thus, users
can be expected to withhold their best price or pricing structure from tie
"Letter of Intent", knowinq that at the time of bidding they probably will have
to bid higher in order to purchase the material. The "Letter of Intent", However,
does assure that they will at least bid, and that the price will not be lower
than the one stated.
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If a formal bid for the sale of a recovered material is to be made with
both a floor price and an exchange price mechanism, one of these prices need:;
to be fixed in advance so that tfie final bids will be comparable. Thus, when
bids are let, the floor price will be specified by the recovery facility and
bids will only be based on the need for an exchange price to be established.
The current letters provide a basis for designating this floor price.
Those "Letters of Intent" which provide a floor price can be grouped togetner
to calculate a guaranteed minimum revenue, assuming the worst possible market
conditions. The results can then be employed to analyze the economic feasi-
bility of the facility. It is worth noting, however, that the floor pri.ce
incorporates any unforeseen risk the bidder may incur and is generally much
lower than any reasonable market price. Such a pegging of the floor price is
to be expected when considering: (1) that the operating period may not begin
until two to three years hence, and; (2) that it is questionable whether long-term
variations in the prices of secondary materials can be predicted. It i:> impor-
tant, therefore, that every effort be made to obtain realistic floor prices
to provide support for the viability of the facility.
Suriima ry
The considerations necessary for successful market development are numerous
and will have their own peculiarities for each situation. As with any essential
element of a resource recovery project, they should be well thought out from
the start. Much of this work is in the developmental stage, and many people
across the nation are putting significant effort into it. With the passage
of time, these efforts will lead to a much clearer understanding of how to
create the bridge that resource recovery represents.
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EPA Technical Assistance Advisor's
Presentation to CHy Council
on the Initial Steps of Procuring a
Resource Recovery System
NSWMA Conference, Dallas
December 8, 1976
Robert A. Lowe
Chief Technical Assistance Branch
Resource Recovery Division
Office of Solid Haste
U.S. Environmental Protection Agency
(Scenario.)
EPA has been invited to meet with the City Council to answer some
questions about their plans to implement a resource recovery system. In
preliminary conversations, City officials indicated that they have read
some of the literature on resource recovery; they have attended several
national and regional meetings over the past few years; and they have
discussed their situation with a consulting engineer, an investment
banker, and several system vendors. They have not yet begun a formal
study that is expected to lead toward recycling their solid waste;
however, they want to do so now.
Having heard that EPA has given information and advice to other
coiwiunities, City has asked us to discuss their plans and to answer
quesrions about how they should approach the problem, what should they
do first, and what important points should be considered.
_EPA's Rolf
Let me begin by explaining the role of EPA's technical assistance
program. Our role is to help provide policy direction to States and
communities. We are not a substitute for consultants. Consultants have
greater expertise than we have. But consultants usually do not serve
their client's needs unless asked the right questions. Many times
governments do not have enough experience with resource recovery to ask
the right questions. Therefore, EPA's role is to assist local governments
in identifying the important questions, and to identify the range of
issues and alternative decisions, and the possible consequences of those
decisions.
Contrary to common understanding, our knowledge does not come from
n Supreme Being; it comes from observing arid analyzing the experiences
of other cities.
Tne City is about the size of Mew Orleans, St. Louis, or Mempliis.
Considering City and County together, the metro area compares in size
vw Orleans, Tampa-St. Petersburg, and Portland, Oregon areas.
T!i--; City generates about 1,000 to 1400 tons per day (depending
OA nor capita waste generation, rates, on whether conmercinl sources are
included, and on how many days per week the waste is collected). The
County yjnerates an additional 750 to 1030 tons p?r day.
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In view of the short remaining life of the City's landfill
and in view of new State and Federal legislation, it is clear that
City has a problem; and thay cannot afford to waste time,
Solving City's problem i; constrained by the debt situation, the
new Stats law on leachate collection, the air pollution situation, and
the sludge disposal problem. These are serious, but they can be overcome
or accommodated.
There are several important things in the city's favor.
City's size and population density means an adequate quantity of solid waste
is there; and public collection means that this waste can be directed to source
separation and central processing systems. There are also potentially
qood markets for waste paper and waste derived energy.
liiiat to look at
There are so many aspects of implementing a resource recovery
system--!t seems that everything must be done first and all at once—
lhat it is easy to become confused. To simplify matters, many cities
have started with a technology approach, identifying markets and
ev.iluacing technologies.
Unfortunately, we've seen many cities start this way and
v".>nd lots of money and lots of time and get no where. They find that
Kuy'vc gone down blind alleys because they did not consider some
very important issues.
We want you to avoid these blind alleys. Ke recomnend that you
do not take the technology approach. We rocormend that you
fjisider resource recovery as a full-scale business enterprise and
I •'••'.> a business approach instead.
Of all the issues that must be addressed, four stand out as being
of primary importance:
o Markets
o Haste supply
o Financing
o Sites
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Markets. I'm sure you are all aware of the importance of securing
markets. With me today to discuss these market issues are
Harvey Gershman, a management consultant, and Alden Howard, a
prospective industrial customer for steam. I defer to them.
Haste Supply. A supply of waste is essential -- waste is the raw
material without which revenues cannot be earned. Obtaining a
supply of waste should not be taken for granted, fortunately,
because City collects its v/aste in its own trucks, it has control
over its 1000-1400 tons per day and can direct that waste to the
system of its choice. But don't make the mistake of assuming that
you can build a 2,000 ton per day plant and get the County's waste.
More will be said about bringing several jurisdictions into a single
system by Steve Lewis, a management consultant with experience in
regional systems.
Financing. The third issue, financing, is so important that
it must"be factored into any city's thinking from the very beginning,
especially in your city where, because the City has reached its debt
ceiling, general obligation financing cannot be used. The city will
probably have to use project financing or some other financing
mechanism secured by a source of revenues, such as a special tax
assessment, that is earmarked to pay for the project and kept separate
from general revenues. Regardless of the mechanssrn, the project
must be structured in such a way that prospective bondholders will
have confidence that their investment is safe. In other-words, the
project must be financeable. Different financing mechanisms have
different requirements that can dictate how a project must be structured.
To make sure the project is financeaole, the possible financing
mechansims and their requirements mint be considered frorn t'ne
beginning of the City's study. We will go into more detail on
financeability and financing mechansims with two investment
bankers, Bob Aldrich and Charlie Ballard,
Sites. Which site is selected depends upon a lot of factors,
including proximity and access to waste generators and to customers,
which will be identified as your study progresses. But as every
elected official knows, siting a solid waste facility is very
difficult; and it is never too early to begin acquiring a site.
There are three other major issues:
• Type of system
• Procurement approach
t Legal issues
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Type of System The type of systems that are appropriate will
be~dictated by the market;?. We have observed that there is a
tendency to limit consideration to central processing facilities
and to overlook source separation systems. The enthusiasm for
large plants may have something to do with the fact that many
companies can make money if a plant is built. Cut the City
can make money—or at least reduce costs—by source separating
if you can get long term contracts with floor prices. Therefore,
we encourage you to consider source separation as an option. There are
many good reasons for this, which will be discussed by John Skinner,
Director of the City Planning Agency.
Procurement Approach. There ar.e three basic procurement approaches:
• The A&E approach, where the city hires a professional
engineering firm to design a system, develop specifications,
and perhaps to monitor construction; then the city purchases
the equipment, materials and labor. The City owns and
operates the system and is responsible for its performance.
e The turnkey approach, where the city buys the system or
the principal components as a package and does not take
title until the system has passed a performance test.
Then the city owns and operates the facility.
• The full service approach, where the city buys a service
from a system vendor who designs, contructs and operates
the facility.
These are described in detail in EPA's Resource Recovery Plant
Inpleirentation Guide. In my dealings with otFer~cities, I have noticed
that their" thinking about procurement is made more difficult because
of misconceptions about two issues:
• Control and responsibility
• Risk and reward
No company will accept responsibility for something unless it has
control over it. For example, no company will guarantee the performance
of a system unless it had control over both the design and construction
of the facility. In an A&E situation, no one but the city has overall
responsibility; and as the Nashville experience shows, it is nearly
impossible to assign the blame if something goes wrong.
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In a turnkey arrangement, the contractor will accept responsibility
until the performance test is over. As an example, with all ths problois
in Baltimore, there was essentially no question that Monsanto was responsible
1'or everything (within the limit--$4 million-- of their contrvctu.tl
obligation). But once the performance test is over nnd a second party
begins to operate the facility, it would be nearly impossible to hold
the contractor responsible if something went wrong because it v/ould
be difficult to prove that the problem was caused by the contractor and
not by the operator.
In a full service arrangement, the "contractor will assume
responsibility for the performance of the system under normal conditions.
But the contractor has no control over some events such as sabotage,
earthquakes, and strikes by suppliers (known as force majeure), and
therefore will not pay for losses due to these events.
I mention this control/responsibility relationship so that
you may be wary of companies—including designers, equipment
manufacturers, and system vendors—that promise--ei ther explicitly
or implicitly—that their design will work or their machinary wjjl_
work. Unless they control the entire system, they cannot guarantee
that it will work and will not back up their promises with money.
Regarding risks and rewards, every city wants to minimize costs
and maximize benefits. So do private companies (system vendors,
product customers, etc.). But every project involves making an
investment without knowing for sure how the future will turn out.
Companies make such investments every day. So do cities. Making
an investment under conditions of uncercainty involves taking a risk.
This risk can be bigger or smaller depending on the size of the
investment, the strength of the markets, the amount of experience
with the technology, the experience of the'designers, and other factor;,.
Companies will take risks if the potential reward (profit) is
large enough. The greater the risk, the greater the potential reward
that is required to make the investment. Cities frequently make decisions
on the same principles, although they generally undertake ''ess risky
projects because they are not created to make a profit nor can they
suffer the consequences of severe losses.
If costs could be estimated accurately—if the future could be
predicted, it would be a lot easier to choose between the A«E and full
"uryice approaches. But actual costs (that won't be known until the
facility is built and operated) could vary widely, depending upon
v.hether certain conditions are favorable or unfavorable.
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Under the best conditions, the actual costs of a project will
be low—perhaps lower than the city's original ostiirtat.es. If the
city buys a system under the Afii" approach wh?n conditions are favorable,
the city is the direct beneficiary through lower costs. If the city
buys a system under the full service approach when conditions are
favorable, the city will be paying the company a profit. And the
cost to the city rrny he more under full service than under ASE,
depending on how efficient the company is.
On the other hand, if conditions are bad, actual project costs
will be higher than originally estimated—perhaps much higher. Under
the A&E approach, the city would pay dearly; under a fu11 service
arrangement, the City would pay the amount originally agreed upon tnd
would be protected from large losses, which the company would have to
absorb (unless they default).
Looking back on the projects that have been built, a few have
been built within their budget. But most projects end up costing
more—sometimes much more--than was budgeted. In view of the risk
factors mentioned earlier, actual costs in future projects are
more likely to be over budget than under.
Which approach is cheaper? Which one is best? EPA has no
preferred procurement approach for all cases; however, in our judgment,
when an investment is risky, we think it is prudent for cities to redur.-;
their risk by securing guarantees from industry; and the rost moaning'-
guarantees are secured in a full-service contract. This approach is
frequently criticized as being too costly, but we think that a full
service arrangement can be less costly in irwny cases. In the long run,
the only system that is too rosily is Mr* <;y;!-pm that didn't uor''
One final word on procurement. Thj ,iumbar of qualified resource
recovery companies is limited. They can bid on only a few projects
at a time. Consequently, they must be very selective about which
jobs they bid on. What this weans for cities is that they cannot
expect the good companies to come beating down their doors. Cities
must make an effort to attract bidders, to demonstrate that they offer
a viable business opportunity.
This, companies have told us, means that cities should do their
homework before they come to the bargaining table. Tor example, they
should select a procurement approach b?Tor? ,1 request for proposals is
issued. They should also resolvs some Important legal questions, such as:
Is negotiated procurement allowed?
Can the community enljr into a put-or pay contract?
Can the community lease nr sell land to indusiry?
Can the community enter into a long-term contract?
Can the community enter into revenue-sharing?
Must the community comply wich split-bidding laws?
What are States salvage laws?
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Don't let yourself yet into the position—that some cities
have found themselves—of issuing a request for proposals \iithout
having answered these questions.
I low to Proceed
Before the other consultants talk more about these issues,
I'd like to make a few observations about how citi?s
cjo about planning and implementing a project. If you look at the
projects that have succeeded, you'll see that they hav3 several
traits in common:
o Project Manager—Each success had one person who
kept the project moving, follovwd up on all details,
and did a lot of work. Committees don't do work;
individuals do. But not department heads:
they're too busy with other things.
o Executive Support—Each success had department heads,
council members and chief executives who './ere
committed to the project and used their power
to get the project approved and moving.
• Coordination—Each success received gudiance and
public support from an advisory task force of some
kind. In addition, each success was tha result
of cooperation between many city, state, industry,
and citizen groups and departments.
e Realistic schedule—Every project that we know of
has taken at least 3 to 5 years to get from the first
planning steps to plant operation. Although every
elected official would like to have an operating
plant to impress the voters before the next election,
it is not realistic to expect that a project can be
completed in a short time.
o Team of consultants--Each success hired not just
engineers, but financial, legal, and management
consultants as well. Some cities did not hire
legal and financial consultants in the early stages
of their planning when they could have done the most
good. But they did hire them eventually.
• Minimize conflict of interests—A conflict of interest
may exist whenever any consultant, advisory task force
member, or anyone else involved in the decision-Making
process stands to profit from particular options that
could be recommended. Such conflicts can be minimi/ed
by disqualifying these individuals or ("inns from follow-on
business. Mot all conflicts ran be eliminated; in such
cases, public recognition of the conflict can hslp
protect the public interest.
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-8-
e Planning expenditures—Each success spent a lot of
money, for feasibility studies, for market research,
for evaluation of proposals, and for negotiations of
contracts. Some tried to skimp in the early phases
and ended up paying more for lawyers and other consultants
later. It does not make sense to quibble about $50,ODD
wehn $50 million is at stake.
One way or another, projects can be built without hiring the
proper consultants; but they always seem to take longer. And these
delays are costly. At present rates of inflation, a $50 million project
will cost about 510,000 more for each day the project is delayed, just
because of inflation.
We are encouraged by the prospects for a successful implementation
in the City, and we look forward to working with you.
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Finance - Ability of Resource Recovery Facilities
Robert H. Aldrich, Vice President
White, Meld & Co. Incorporated
There are two measures of the success of a financing: the first, that
the necessary capital is raised; and second, that the cost of capital is reason-
able in comparison to the money market and considering the risks associated with
a particular financing. The ultimate measure of success, of course, is that the
project itself meets its objectives and the investors are fully and properly
compensated.
Financing of solid waste resource recovery facilities is rapidly develop-
ing into a specialized field, due primarily to unique features of
the business and the need of the investment banker to have an in-depth knowledge
of the industry. It is unique because, by its very nature, resource recovery
requires the combined resources of both the public and private sectors.
A community looks to resource recovery to provide a reliable and eco-
nomic means of disposing of solid waste in an environmentally sound manner. The
main resource the public provides is a continuous supply of solid waste, and a
mechanism by which to pay for the service of disposal. The private sector, on
the other hand, looks to resource recovery as a natural extension of its engineer-
ing and manufacturing technology, and a means of generating profit by providing a
basic service to a community and marketing or utilizing the resources contained
in the waste stream.
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Federal and state laws and regulations controlling the financing of
resource recovery facilities have recognized the need and desire for joint
public/private participation in resource recovery and have provided for the in-
vestment community financing mechanisms which are unusual and quite attractive.
The main features of the financing mechanisms are that the facility can be pri-
vately owned and operated and that the owner of the facility can take tax advan-
tages of ownership including investment tax credit, accelerated depreciation, and
deductions for interest expenses — and yet the facility can be financed using tax-
exempt municipal bonds, where the interest income on the bonds is exempt from
state and Federal taxes. This combination of benefits — tax ownership avail-
able only to the private sector, and the low interest costs of tax-exempt munici-
pal bonds normally restricted to public debt, provides to resource recovery pro-
jects the opportunity to obtain a comparatively favorable net cost of capital.
However, whereas the financing mechanisms and alternatives appear
attractive, and they are, the finance -ability of resource recovery projects is
still dependent upon the underlying strength of the project, and the security
features structured into the financing package. Risks must be identified,
and the financing structured so as to minimize these risks and to assign respon-
sibilities to the appropriate parties, generally through contractual relationships.
What the Investment Community Looks to in a Resource Recovery Financing
This presentation assumes that the facility is to be financed as a
project financing using revenue bonds, equity, etc., and not secured by a general
obligation of a community, state, or private corporation.
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Resource recovery facilities must compete for funds in the marketplace.
In general, resource recovery facilities are competing in a specific market —
the long term municipal bond market, against state and local general obligation
or revenue bond issues for school construction, housing, hospitals, sewage plants,
etc. In 1976, the total bonds sold into this market will be approximately $30-
billion. While the cumulative to-date dollar value of solid waste bonds has been
low (less than $200K), the size of the individual solid waste bond issues nave
been comparatively large and growing, and the annual requirements are expected
to rise over $1 billion per year.
In resource recovery projects, we look to the following in analyzing
the finance-ability:
• The need of the community, as measured in terms of available solid
waste and its alternative method and economics of disposal.
• The ability and the proposed mechanism by which the community will
pay for the disposal service — the "tipping fee".
• The state of the technology to be utilized — including the history
of operation; the strength of the contractors; and the form and
substance of the guarantee of the contractors to convert solid waste
into saleable resources in a reliable and economic manner over the
term of the financing.
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• The availability of reliable long term markejts for the recovered
resources and the nature of the purchase contracts.
• An economic analysis of the project, by a reliable inde-
pendent engineering firm, to determine that the facility will be
able to operate at the projected costs and generate the required
revenues.
• And finally, the security features built into the financing itself
including: reserve funds, payment schedules, guarantees, and cover-
age ratios.
The investment community is positive in their reaction toward resource
recovery projects, recognizing the basic need of such facilities to communities
as well as recognizing the quality of the private sector companies participating
in this industry. From time to time, in our natural competitive fervor, we tend
to criticize our competitors' systems and services, seeking to gain some compe-
titive advantage for ourselves. Let me state here and now, that this form of
competitive activity is counter-productive to the development of our industry and
can only do more harm than good since the investment community is not in the
position to judge the relative merits of rumors, and will, unless this trend is
checked, be to the detriment of all resource recovery projects. This could have
costly consequences to our industry.
Roles of the Community
The decision by a community on whether or not to undertake a resource
recovery project is generally based upon an evaluation of comparative economics —
comparing the cost of landfill with the alternative of implementing a resource
recovery program.
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The finance-ability of the facility is greatly strengthened if the com-
munity has limited access to alternative disposal sites. Where land-fills are
running out of capacity, and/or where state laws or policies are restricting the
use or increasing the cost of land-fill, resource recovery projects look most
attractive.
The ability of the community to control the flow of solid waste to the
facility and to pay for the service is critical to the financing package. At
times the ability to pay for such service is questionable in certain financially
troubled urban areas. However, it is our opinion that because of the critical
nature of reliable solid waste disposal in such areas combined with strong con-
trol over the flow of solid waste, the project financing can be equal or superior
to general obligation bonds of those urban areas.
The Roles of_the Contractor & Operator
The private sector participant should obligate itself to construct the
facility to meet predefined performance specifications at a price which allows
for inflation and a reasonable contingency. Further, the contractor, or an opera-
tor if not the same, should enter into firm contracts over the full term of the
financing to provide the essential services of reliably disposing of the solid
waste and providing specification grade by-products for sale.
The finance-ability of the project is directly related to the financial
strength and commitment of the private sector participants. Of most importance,
is that the technology to be used be one that has been demonstrated to the point
where the investors and community are satisfied that the facility will perform
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its function reliably and economically over the term of the bonds. The technical
competence of the private sector participants is a further measure of the quality
of the project.
Importance of the Market for Recovered Resources
In order to provide adequate revenues to the project, firm long term
take or pay contracts must be negotiated for substantially all of the resources
recovered in the operation of the facility. Since energy is a major source of revenue
it is most important that the energy purchasers not only commit to purchase the
output of the facility, but that the investor be satisfied that the pur-
chasers are financially sound and that the intended market will exist for the
term of the bonds.
The contracts negotiated should provide for escalation of prices, gener-
ally tied to alternative energy costs to the user.
The Use of an Economic Analysis
An economic analysis of the project over the terrr of the bonds must
be included in the basic financing package. Included in analysis should be a
complete breakdown of the projected cash flow of the project analyzing the anti-
cipated revenues and costs (a profit and loss statement) as well as projected
balance sheets on the project itself. The report should include a sensitivity
analysis measuring the impact of various levels of operating, maintenance and
replacement costs, projected revenues, and financing assumptions.
In addition, the economic analysis should provide to the investor the
coverage ratios (a measure of the availability of funds to repay principal and
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Interest) expected under various operating conditions. This coverage ratio should
be sufficient to satisfy the investor that he will be properly compensated.
Additional Security Features
The additional security features built into a resource recovery financ-
ing should include:
l) A reasonable (one year) reserve fund to pay principal and interest
on the debt.
2) A reasonable reserve fund for maintenance of the facility, as well
planned replacement of certain key components of the facility.
3) An equity contribution to the project by the private sector, not
only assures the investor of the level of commitment by the operator,
but reduces the level of annual debt service.
k) A "gross tipping fee" concept may be used. Under this concept the
community obligates itself to pay a gross tipping fee adequate to
provide the payment of debt service and operation and maintenance
costs. Through predetermined sharing formulas revenue derived from
the sales of energy and recovered materials is then rebated to the
community providing the "net tipping fee". A contract between the
community and the operator can provide for a guaranteed rebate to
the community from the operator if revenues are not sufficient.
5) A land-fill must be available to dispose of the residual waste
from the facility as well as to provide a stand-by for periods in
which the facility is inoperable.
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While the above comments deal in general with project financing using a
combination of revenue bonds and equity, it is, of course, possible to provide
additional security to the financing in the form of guarantees by the community,
the state, the Federal government or the private sector participants. These
guarantees can take several forms including: general obligations, special tax
revenue bonds, moral obligations, price supports, or some limited guarantees.
An example of the limited guarantee is the case in Saugus, Massachusetts where
the private participants guaranteed to provide additional capital to the facility
up to the total tax benefits they derived as owners of the facility.
The various contractual and security elements discussed throughout this
paper are representative of the requirements for a successful resource recovery
project financing. However, due to various constraints and obstacles, the ideal
is seldom achieved. Certain security deficiencies or risks can be accepted by the
investor at a cost to the project, but there are limits to the extent that de-
ficiencies may exist and a financing be accomplished.
This paper, due to time constraints, did not attempt to deal with the
legal questions involving the issuance of debt or forms of procurement. Nor did
it deal with the critical problems associated with keeping the debt off the balance
sheet of the private participant (a key element in a financing program), or with
the constraints imposed by law or policy on the community of having the debt in-
cluded in its debt limit, thus impairing its future borrowing capacity.
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In conclusion, financing of resource recovery facilities can be suc-
cessfully accomplished through project financing without the use of general obli-
gation or special tax bonds. The key factor is structuring a financing which
properly assigns risks and rewards, and which is secured not only by strong con-
tracts between financially and technically reliable entities, but also by strong
commitments on the part of the communities and the private sector participants.
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Project Interrelationships
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Financing Options for Resource Recovery
Charles A. Ballard
Vice President
Dillon. Read and Co., Inc.
Thank you. Any discussion concerning financing options for solid waste
disposal/resource recovery systems iriust be viewed objectively. We are,
after all, discussing a new industry - one, in fact, so now that the
historical lack of meaningful investment, by definition, precludes
widely accepted financi;il precedents. Nevertheless, some patterns arc
beginning to emerge, albeit far more slowly than might be considered
in the Nation's best interest.
The financing of solid waste disposal/resource recovery systems should
not be viewed as unique. Financial alternatives must address operating
objectives, and often these objectives cannot be set in concrete, but
rather are subjective and result from preconceived bias, past experience,
or local circumstance.
I felt it might be helpful to review the approaches that four other cities
are employing to finance solid waste disposal facilities. Each of these
cities has embraced one of a series of options, specificallv:
the issuance of General Obligation Bonds;
the issuance of Special Revenue Bonds;
the issuance of Industrial Development Revenue Bonds;
financing from the private sector; or
combinations of the above.
Reviewing each option briefly, General Obligation Bonds commit the full
faith and credit of a municipality to the repayment of the principal of,
and interest on, borrowed funds.
Special Revenue Bonds may take numerous forms, but essentially, a stream
of municipal revenues is pledged to secure the repayment of bonds issued.
These revenues may be from a special taxation district, an unrelated
revenue district, the financed project, or from some other source.
Industrial Development Revenue Bonds may be employed to the extent that
the financed project meets certain requisite conditions of the Internal
Revenue Code.
These first three options generally involve tax exempt financing, i.e.,
the interest payable to bondholders is exempt from Federal income tax
under the appropriate provisions of Section 103 (c) of the Internal
Revenue Code.
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Private Sector Financing involves, either directly or indirectly, a pledge
of the credit of a participating corporation.
Additionally, each of the preceding four options may bo combined to
obtain necessary funding.
Perhaps the case-by-case review of four actual examples may bring into
better focus the application of the f Lancing options described.
(Insert Slide 2).
As may be expected, each of the subject cities - and I have been, or ain
currently, involved with each, - have varying populations, characteristics
and objectives.
City A has a service area population of approximately 250,000. The stated
characteristics of City A regarding its solid waste disposal/resource
recovery facility include the following:
1) the City desired no ownership of the subject facility;
2) the City desired no direct management responsibility for the
operation of the facility;
3) the City had no credit support that it could offer to the facll:ty's
financing; rind,
*)) the City desired no participation in facility profits.
Simply, City A's Facility objectives included the dependable and environ-
mentally sound disposal of solid wastes, and partial recovery of these solid
wastes.
City B has a service area population of approximately 850,000. It desired
no direct facility ownership or management responsibility for a twenty year
period. It had no credit support to offer, but it did desire a meaningful
profit participation. As with City A, City B desired dependable and environ-
mentally sound disposal of solid wastes but it had as an additional objective,
total resource recovery.
City C has a service area population of approximately 550,000 people. City C
desired immediate ownership of the facility, a limited management respon-
sibility, was able to afford limited credit support and was interested in a
profit participation. Its Facility objectives were otherwise similar to those
of City B.
City D has a service area population of approximately 1,300,000, it desired
ovmership of the facility upon its completion, limited nanagenent respon-
sibility, and through State Bonding, had strong credit support available.
Its profit participation desires and other Facility objectives were similar
to Cities B and C.
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City A'L solution was not an overly complex one, but often simplicity
rules the day in meeting objectives. City A entered into a disposal
contract with a private sector operator for the disposal of its solid
wastes. The contract provided for hauling services as well as for
disposal cervices. Through the powers chanted to the City under its State
laws, the City VMS authorized to issue Industrial Development Revenue
Bonds for the acquisition or construction of facilities which inure to
the benefit of the City, the State, or its citizens. The City could issue
such bonds, limiting bondholders' resource to those revenues, pledged to
secure the bonds.
To generate such revenues the City entered into a twenty-year lease with
the operator for the use of the facility, and issued its limited recourse
bonds in an amount sufficient to construct the facility. These bonds
were secured by the pledge and assignment of the lease payments receivable
from the project operator. The proceeds of the bond issue were placed in
trust and construction contractors were paid as delivery progressed. The
operator gave its guarantee of lease payments to Bondholders and, further
entered into contracts with certain Dy-product purchasers for the purchase
of recovered items. The financing has been completed; the project has
been completed; and the City and the operator have each achieved its stated
objectives. Through the City's auspices the operator was able to receive
lower cost tax exempt financing, but was required to pledge its direct
credit to secure such financing. In this example, the credit of a private
sector corporation was combined with a city's authority to issue tax exempt
industrial development bonds to finance the solid waste disposal facility.
City B had a more complex problem. The cost of a full resource recovery
operation servicing the needs of 850,000 people was substantially in excess
of that experienced by City A. Few corporations are capable of, or, if
capable, desire to employ their credit in such manner. Nevertheless, the
funding problem was solved by the structure shown. Tracing
first the contract flow, City B encered into a twenty-year contract with
a private sector operator to provide for the disposal of certain minimum
amounts of solid waste on a monthly basis. If the City did not deliver
such minimum, it would nevertheless be required to pay for the disposal of
the minimum. Although the price per ton for disposal was established,
it was to be adjusted to reflect escalation as determined by certain
independent price indices. The operator then entered into a twenty-year
agreement with a principal energy purchaser under which the energy
purchaser agreed to purchase any and all energy delivered at a price based
upon its alternative fuel costs; such price however, could not fall below
a stated minimum. Simultaneously, the operator entered into long-term
purchase contracts with other by-product purchasers. Each of these latter
contracts contained minimum "take or pay provisions", providing that by-
products would be purchased at prices based upon market conditions, but in
no event would such prices be below stated minimums.
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As with City A, City E ted authority under its State laws to issue,
through an industrial development authority, industrial development revenue
bonds. The operator entered into an agreement with the industrial
development authority to lease the completed facility for twenty years at
annual payments sufficient to amortize the debt issued. The operator
secured its obligation to make lease payments with a pledge of the- disposal
contract with the City, a pledge of the energy purchase contract, and a
pledge of the contracts with other by-product purchasers. To complete
this "circle of obligations" the operator's parent company extended a
performance guaranty to both the City and the Bondholders which assured
that the project would be completed in a timely fashion and would operate
in accord with performance specifications.
City B's financing has been completed, and the facility is currently under
construction. The issuance of industrial development bonds combined with
the City's contractual obligation and several forms of private sector
credit made the financing feasible.
City C, as you remember, desired immediate ownership of the facility and
had limited credit support available, but its other objectives and
characteristics were similar to those of City B. As with City B, the capita]
cost of City C's plant is to be signifleant. In general, these objectives
and characteristics dictated an even more cotiplex solution to the financing
proolem.
Let's again look at the contract flow. While the service area
population of City C was 550,000, nearly half of that population resided
in the Comity surrounding the City's corporate limits. The facility, when
completed, would inure to the benefit not only of the City residents,
but also to those of the County. Accordingly, negotiations were held with
the County, and the County ultimately agreed that it wouid Lend direct
support to the to-be constructed plant. A Cooperative Agreement was executed
by the City and the County, each agreeing thereunder to make available
its general funds in the cumulative amount of approximately 30 percent of
the facility's installed cost. A bond trustee, acting on behalf of the
Bondholders, was made a beneficiary of this agreement.
City C then entered into numerous 25-year agreements with energy purchasers
providing for the long-term purchase of energy at prices to be adjusted to
reflect the plant's actual operating and capital costs. No profit margins
were included. The City further entered into contracts with independent
construction companies for the construction of the subject facility.
Because City C desired only limited responsibility for the facility's
operation, a contract was entered into with a member of the private sector
for the supervision of the project's construction and initial operating phases
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The trustee was, by assignment, made a beneficiary of all of these agreements,
based on this security afforded by these contracts, other ordinances and
legal action taken by the City and the County, the trustee should be in a
position to issue revenue bonds for the remaining facility cost. Revenue
bondholders would have first claim on all project revenues, such claim being
prior to repayment of the general funds advanced by the City and County.
Tills financing is currently under negotiation. Under such a structure,
General Obligation Bonds, Industrial Developnent Revenue Bonds, and private
sector financing, through the assignment of "take or pay" energy contracts,
are being combined to accomplish the project's funding.
City D's objectives were similar to those of City C except in one particular
regard. Strong credit support is available, through State auspices, once
the project is constructed and in operation.
Accordingly, City D has two stages to its financing plan, one occurring
during the construction stage, the second during the operating stage.
First - the construction phase - and again, let's follow the
contract flow. Because the County government has direct responsibility for
the disposal of solid wastes, that political sub division is to he employed
in preference to the City. The County will enter into an agreement with
the State to provide for the facility's pciTnnent funding on completion.
The County further will enter into agreements with a private sector ir-jmber
for the construction and operation of the subject facility. Tne construction
phase includes a "turn-key" price. The major energy purchaser will agree to
purchase the facility's energy by-products for a twenty year period. Because
the private sector operator will be involved during the operating period,
it also will be party to this agreement.
Based upon this agreement with the County and the energy user, the contractor
may enter into the construction contracts for the Facility's construction.
To finance the construction phase several additional agreements were required.
The funding agreement between the County and the State provides that the
State will make its funds available prior to the commencement of construction,
which funds will be held in escrow by trustee B until completion of
construction. Such agreement addresses the concerns of a changing State
legislature, administration, etc. Trustee R, having funds on deposit with it,
may then enter into a funding agreement with Trustee A, providing that upor
"completion" such funds would DC transferee! to trustee A. Trustee A, armed
with trustee B's agreement, a construction loan agreement with the operator,
and an agreement with the operator's parent coupon/ guaranteeing timely
completion, may issue notes, secured by such agreements, to short-term
lenders to fund construction requirements.
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When construction is completed and operations commence,
the structure changes slightly. Instead of a construction performance
guarantee the contractor's parent company will have a continuing operating
performance guarantee, assuring both the County and the energy purchaser
that the facility will perform in accordance with design specifications.
The State funds, heretofore being held by trustee D, will be transferred to
trustee A who will then repay construction lenders, and other contract
funds advanced by the contractor on behalf of the County. Energy payments
from the energy purchaser and operating payments from the County will be
sufficient to pay operating and maintenance expenses of the contract, and
hopefully, allow seme cash flow to accrue to the County's benefit.
Under this structure, General Obligation Bonds and Private Sector capital
will be jointly employed to fund the project's completion and capitfl
costs. There, of course, are other options including leveraged leasing,
and other combinations, which may, in your particular instance, address
particular objectives and area characteristics. Each must be examined
carefully with competent financial and legal counsel to assure the best
possible financial result. Thank you.
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CONTROLLED-AIR INCINERATION —
KEY TO
PRACTICAL PRODUCTION OF ENERGY FRO*! WASTES
by
ROSS E. HOFMANN
President, Ross Hofmann, Associates
Coral Gables, Florida
For the past seven years, RoAi Hofmann, AM>'M'?O *i. >• Leon inti-
mately involved with the development of the small \*j. t- energy pro-
duction systems using controlled-air incinerat11.., believing that
they offer a major economic and technical solution to our fossil
fuel shortfall.
It is estimated that at least 425,000 tens of residential and
commercial solid waste is generated daily by American communities.
A considerable additional amount of combustible solid waste is gen-
erated by thousands of factories and institutions within these same
urban areas. The municipal segment alone apparently contains a
daily potential energy content of over four trillion, 250 billion Btu.
This much energy is too valuable a resource to be buried in
landfills or destroyed by a simple combustion process. In one year,
the municipal and privately generated solid wastes in these communi -
ties can produce energy equivalent to over 1.5 trillion cubic fef
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of natural gas — more than the shortfall estimated to exist. Al-
ternatively, it can produce the energy equivalent of over 10 billion
gallons of oil currently firing thousands of boilers throughout the:
nation. It is capable of producing over 900 billion pounds of high
pressure steam annually, either for electrical production, or for
direct process and heating use in thousands of factories and critical
institutions, such as hospitals.
There is nothing new about "resource recovery" from solid waste.
A few demonstration projects, both federally and privately financed,
have been going on for five years. < Some projects have attempted to
remove and sell the metals, glass, and paper products from the waste
stream, with varying success due to the vagaries of the scrap markets.
Others have looked at the potential for extracting the energy in
waste, ranging frou complicated and expensive chemical processes,
such as pyrolysis, to direct energy production through incineration.
Three direct energy processes have emerged for the production of
steam from some sort of boiler. Milled combustibles, or refuse de-
rived fuel (RDF), in _he solid waste stream have been used to augment
coal in utility company boilers for the production of electricity;
or have been used to fjra boilers as the sole fuel source. Other
energy production plants have attempted to use "water-wall" incin-
erators, lining tha o?:imary chamber of a conventional, large-scale,
municipal incinerator with boiler tubes for the direct product-ion ct
steam and/or turbine-produced electricity. The third approach .' as
•oncentrated or small, "controlled-air" incinerators, with matching
separate boilers, installed in identical modules to produce stenm
r..r immediate process or he.ating use. This thirr1 approach mav prove
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;he most dramatic o ~ I" , .. rre succrs^es to date, oot.; • -u • 'I '
and economically, ;:r>rtir,u<- .
Most o-i i."ii nq d^mmi"? t rnt ions of resource recovo/y pr<-vTS< . ^
ooii to coni-rr." -.-itr- on a mnns production approach. This h.ip c.irri i>,i
over into rv,ose that utilize solid waste for energy production. It
is usual-/ O'-.visioned that waste from large ciuif;s and their sur-
roundinq subarbs will be transported to a central processing plant,
with a capacity of up to 1,000 tons dailv 01 nK.re, to take advantage
of the economies of scale.
This ignores some simple economics when ceal^rg with solid waste
-nanaqement. The most expensive aspect is the w~ st cf tL insportation.
Tie greater the mass production, the wider tha Ere? nat mu^t be
•. f'Cfid to obtain the waste and haul it to a jeatrj. point, and the
,ii3:5e.r the overall cost. This has been dramatxca I! / pointed out in
• t ilysis of sanitary landfill total costs whicr, ha-^e ri ?Qn consider-
ably as available Rites have involved longer an-i longer hauls from
original pick up arp.is For example, a half hocu or»r way trip is
estimated to cost ?2,.-, i er ton hauled, while a twc, hour trip is es-
timated to cost $7.30 per ton hauled, to which musi. be added transfer
station costs of from $1.20 to $1.50 per ton. T< date, the design
and construction costs of the mass production piants have been so
high, compared to product net revenue, that a reasonable payout period
appears difficult to attain. Further, there is almost a direct cor-
relation between the locations that generate waste, the quantities
they generate, and a direct demand for process or heating steam on
a short haul basis. The economics appear to lead to modular, str.i
tegically located, small installations. A large proportion of •
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pot ntial users need energy to survive, but in relatively small
qua, titles that match closely the amounts available from local wastes.
BASIC CRITERIA
For any energy production system to be practical, it must meet
several basic criteria. It must be environmentally acceptable in
present day America. With incineration, this means air emissions
must pass stringent codes. It should be economically feasible. If
inflation is to be halted, total ownership costs of design, construc-
tion, and operation must be kept to a minimum. It must be safe to
operate, both in the mind of the public and in reality. Technically,
it must be sound, and capable of technological up-gradanq at reason-
able cost as engineering advances t.ikc place. It obviously .should
deliver far more energy than it consumes (hopefully, in ratios of at
least 20 to 1 or better). The energy should be saleable, immediately,
in a competitive market. This latter point is particularly applicable
to waste heat, as it is difficult to store and is normally unr-il nn
generated.
Large municipal incinerators, when converted to steam production
units, have experienced problems in meeting these criteria. Emission
rates have been high unless expensive and rather sophisticated air
pollution control devices are installed. Conventional incinerators
have produced a rather contaminated gas which coats and corrodes boil-
er tubes. Costs of operation and total ownership have been high enough
to affect the feasibility of the process.
The "small" incinerators available today are mass produced in
a factory and shipped, either completely assembled or in large sections,
to the site, resulting in low capital cost. To achieve a
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given capacity, they are normally installed in identical modules,
capable of any amount of desired expansion as needed. They utilize
pntiroly difforont engineering principles from the large conventional
incinerators. As a result, they have solved the emission problems
and the economic problems that have plagued incineration for so many
years. After automatic air treatment within the- unit, they produce
.1 fl.iMvoly nnrontaminntod q.in from Hir> burninq w.iMlo. This high
temperature gas is passed through a specially designed packaged boil-
er, or air mixer, as the fuel from which the energy is extracted.
END USF.S OF THE F.NF.nr.Y PRODUCKD
In an effort to achieve maximum pfficiency, tho energy of the
waste heat gases has been used in a variety of ways. In general,
these are directly related to the needs of the institution, industry,
or municipality considering tho purchnsr-. Thn most common method
is to produce steam or hot wator dirc-rt ly in a closo-coupled boiler
for process, comfort, or sanitary use. In institutional and dwelling
or office complexes, as well as factories, the heating of air for
comfort conditioning is being investigated, utilizing multi-tube
heat exchangers mounted in the exhaust system with or without blowers.
Direct conversion of the heat exchanger can also be made for heating
water for process or sanitary use. This system can be sophisticated
by the use of a thermal fluid heat exchanger for more efficient re-
covery of the available heat and in situations where high temperature
process heating media is useful. Another heat recovery system is to
mix ambient air with the exhaust gases for process drying, curing
operations, or conveying air to maintain materials at elevated temp
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eratures. Many plants and towns are now investigating the use of
low pressure steam turbines both for mechanical drives and for gen-
eration of electricity.
With the steam production systems, the efficiency of the boilers
is in the range of 60% to 75%, depending on the design. Emissions
in the stack gases, under normal operating conditions, have been
proven to be as low as 0.03 grains of particulate matter per cubic
foot of dry flue gas corrected to 12% CO2- Net savings of fossil
fuel consumption are as high as 95% over a direct-fired boiler of
equivalent efficiency. Steam sales revenue? are recapturing all
total ownership costs in many installations and tiermitting an oper-
ating profit in waste disposal.
CONSTRAINTS OF SOLID WASTE AS A FUEL
Obviously, solid waste is not as efficient a fuel as any of the
fossil fuels. It has a lower Btu output per pound in its average
"as received" condition; greater weights must be burned to produce
the energy equivalent of oil, coal, or gas. The heat output of
solid wastes "as received" averages from 3,000 to 9,000 Btu/lb. The
majority is one-half to one-third that of coal. A pound of #2 oil
releases four times the enrgy of the equivalent weight of solid waste.
Waste has not the compactness of fossil fuel, and far greater volumes
must be burned to reach equivalent energy output. Oil measures 31
to 35 cubic feet per ton; coal measures 45 to 50 cubic feet per ton;
solid waste usually ranges in density, in its "as received" condition,
from 130 to 400 cubic feet per ton. However, it also contains, by
weight, up to 30% moisture and up to 30% non-combustibles, neither
of which contribute to the release of energy. The combustible port-to.
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has densities as low as 650 cubic feet per ton.
Hence, the fuel required in the average 70% efficient direct-
fired boiler to produce 1,000 Ibs. of steam would be approximately
1,440 cubic feet of natural gas or 10 gallons of #2 dieael oil, com-
pared to from 250 to 500 Ibs. of waste in a waste heat boiler. De-
signers of waste heat recovery systems accept these ratios. The
materials handling equipment and the engineering of combustion sys-
tems provide for the lower densities and larger volumes of fuel
(solid waste) that must be charged to produce satisfactory energy
recovery.
POLITICAL CONSIDERATIONS
Solid Wdsbu as a jjolcnlial fuel is becoming increasingly val-
uable. This has led to political discussions on federal, state, and
local levels, concerning the ownership of waste and what should be
done with it. This Uittlo is sh.ipinq up between regional control,
with maun proclucLlim, muIt i million dollar, solid waste resource re-
covery systems, and the small controlled air systems that are being
promoted on a satellite basis for large cities, or for use in the
smaller towns, or in-house for factories and institutions. With
solid waste at last being regarded as a practical fuel for the pro-
duction of usable energy on a profitable basis, we feel that this
battle will intensify during the coming years.
In 1975, Public Service Commissions entered the picture because
controlled-air incinerators normally required allocations of fossil
fuel to at least start the combustion process'. Some states, such as
Arkansas, have already handed down landmark decisions concerning the
allocation of natural gas to the plants that are producing ene-'cy
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from solid waste. In summary, they have stated that such plants
produce up to 90% more energy than they consume in fossil fuels,
and, therefore, should be granted a high priority in the allocation
of fossil fuels such as natural gas. The implications of such a
decision are considerable for any town planning to install a munic-
ipal plant for the burning of its waste and the selling of the entsrgy
to nearby factories.
ECONOMIC REALITIES
During the past 18 months our firm has performed feasibility
studies on controlled-air incineration — waste heat recovery sys-
tems in a large number of communities ranging in population from
25,000 to 250,000. A primary goal of these evaluations was to de-
termine whether there was an adequate match between the generation
of energy from solid waste and the energy requirements of commercial
buyers. In all studies the concentration has been on the "bottom
line" of a profit and loss statement and on comparisons between the
"regional" and the "local" approach.
Most engineers and accountants have known that the cost per
ton of design capacity of the small energy production systems is
considerably under the per ton cost of the large mass production re-
source recovery systems. The small systems range in installed cost
from $12,000 to $14,000 per ton design capacity, as against c-ipitaj
costs per ton that are four to five times larger for the mass pro-
duction systems.
A surprising result of the audits of the small systems was the
'. I*- "loratinq cost we found. Americans have always bocn led to
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believe that with mass production, operating costs fall off drastic-
ally. Promoters of the large systems have inferred that their labor
costs per processed ton would be extremely low. Intensive auditing
of the figures by our firm and the other engineering concerns has
revealed that this is not the case. Recent audits have revealed
that total operating costs of small municipal plants (with outputs
as low as 100 tons per day) have been less than $6.25 per ton. None
of the mass production plants have apparently been able to approach
this low a figure.
These are gross operating costs from which must be deducted
the income from the sale of energy. When the income figure is ap-
plied, all of the existing small plants appear to be generating a
profit for their municipalities.
Table 1A shows the capital costs for plant and equipment of a
typical 120 ton per day municipal plant, with a cost per ton of de-
sign capacity of 512,417. This figure is average for plants in this
size range in 1976.
Table IB shows the annual operating costs. Without interest
and depreciation they amount to $7.76 per ton. When commercial in-
terest at 9% is added and the plant and equipment are completely de-
preciated over a relatively short time period, the total ownership
costs increase to $14.74 per ton.
In this particular plant tipping fees are charged on a basis
equivalent to what the municipality figured were the real costs of
operating (and charging for) its sanitary landfill. The steam sales
fontiact that was negotiated with a local industrial plant is tied
>..itc> the yuing price of fossil fuel and the steam is sold at a price
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approximately 15% lower than the industry can produce it in its own
boilers. Table 1C shows the "bottom line" that is currently being
realized by the municipality on the operation of the plant under
commercial accounting methods with rapid depreciation and full com-
mercial interest being charged against the venture. Over the life
of the plant total profit on the $1*5 million investment would be
$4,566,000. If fossil fuel prices rise steam revenues and hence
profit will rise accordingly.
In addition to the approximately 100 municipal plants that are
installed, under design or being seriously considered at present,
several hundred institutions such as hospitals and universities, and
an even larger number of factories have either installed or committed
to these same heat recovery systems for in-house use, to virtually
eliminate hauling fees, and to reduce fossil fuel costs by producing
energy from their own wastes.
Installed capital costs of these installations usually range
from $100,000 to $170,000. The return on investment is proving ex-
tremely attractive. Table 2 shows the operational savings being ex-
perienced by typical hospitals — an average pay back of from 27 t.o
38 months. Factories are finding even more rapid pay backs, in some
cases as low as 19 months. When one realizes that a medium sized
factory generates 20 tons or more daily of high Btu waste, this is
not surprising.
Futurists predict that, within 30 years, all resources will be-
come more limited for western civilization, that there will be less
and less waste generated, and the fuel for waste energy production
will gradually disappear. In the meantime, each of us still produces
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almost five pounds of such waste daily. It can be put to practical
use immediately.
Equally important, compared to all other processes being offer-
ed as an alternate to fossil fuels where higher temperature energy
is desired, the solid waste direct 'energy production systems appear
to offer the greatest net oncrcjy return or qain against the energy
required to operate these- processes. This is based on the studies
made to date on solid waste as a resource, as well as current designs
of other alternate energy processes.
The importance of the waste energy recovery process is that it
workn — .\i\il il workii now. II in not ,i I hcory th.it requires 10 moro
yours of development. II is; not a cure-all, but it can make a tre-
mendous impact on the present energy shortfall.
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TABLE 1A
CAPITAL INVESTMENT
MUNICIPAL SOLID WASTE ENERGY PRODL'C^ION PLANT
(120 tons per day design ca:>a<*it,'
Vn (ineerxng. Construction Management, Legal ,. PSa .
Permits and Emission Testing , ,, f> 128,800
? a.\? Acquisition, Site Preparation, Sewer SjSti", "ojrs,
Landscaping, Fencing and Signs C>4,300
B-iilding Construction <1 9 ,000
Incineration - Steam Boiler System, with Suppc ;t
Equipment, Instrumentation and Steam
Delivery Lines, -Installed and Tested ... 9iC.4CO
Truck Scale , ,. l.,500
TOTAL CAPITAL COST 51,490,000
Cost per Ton of Design Capacity: $12,417
MOBILE EQUIPMENT
Front Loading Tractors $ 22,000
Pick-up Truck 3,900
Furniture and Supply Storage Facility 3 ,800
Residue and Waste Containers 7,000
TOTAL $ 36,700
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TABLE IB
ANNUAL OPERATING COSTS
120 TON PER DAY PLANT
(34,320 tons per year)
Labor, Plant and Office * -04 . = 70
Frinoe Benefits i> 7-7''
Operating Supplies:
Auxiliary Fuel (#2 Oil) 3*-. • ' ''
Boiler Treatment q / •'"
Utilities - Water, Electricity, Phone ID ,«•( >
Plant, Vehicle and Office Supplies •> 800
Vehicle Fuel 1,400
Insurance 15,700
Maintenance Fund 40 , 300
Residue Disposal (Net Cost) 28,600
TOTAL OPERATING COSTS $ 266,370
Cost Per Ton of Waste: $7.76
Interest on Investment @ 9% $ 134,900
Depreciation on Buildings and Plant
(Straight Line 15 Years) 99,333
Depreciation on Vehicles (5 Years) 5,180
TOTAL COSTS $ 505,783
Cost Per Ton of Waste: $14.74
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TABLE 1C
INCOME STATEMENT
120 TON PER DAY PLANT
SALES REVENUE
Tippj n
-------
- TABLE 2 -
ANNUAL OPERATING COST SAVINGS
IN GENERAL HOSPITALS
Census
Size
300
400
500
600
700
Fuel
Savings
(Oil)
$22,648
30,198
37,201
43,986
50,549
Compacting
& Hauling
Savings
$13,450
16,800
20,600
25,900
30,600
Total
Savings
$36,098
46,998
57,801
69,886
81,249
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EXPLOSION PROTECTION IN REFUSE SHREDDING
By
Robert G. Zalosh
Factory Mutual Research Corporation
Factory Mutual System
Norwood, Mass. 02062
ABSTRACT
There have been over 100 reported refuse shredder explosions in the last
few years. It is virtually impossible to eliminate all shredder explosions
because of the wide assortment of potentially explosible materials, i.e.,
flammable vapors, gas, and dusts and chemical explosives, that can be present
in municipal refuse. The responsible material was not identified in the
majority of shredder explosions, but flammable vapors have been identified
in many others. Commercial explosives, notably dynamite, which have occasion-
ally been involved, are the most difficult to protect against. Explosion vent-
ing, explosion suppression systems, and continuous waterspray in the shredder
appear to be effective damage control measures for deflagration type explosions
caused by most flammable gases and vapors. Although venting has been the measure
most often employed, the majority of shredder vent designs have not utilized
current explosion venting design technology.
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INTRODUCTION
The use of shredders to process solid waste has increased remarkably during
(1 2)
the past five years. According to the recent Waste Age surveys ' of shred-
ding operations in the United States and Canada, the number of reported refuse
shredding installations has multiplied approximately fivefold from 27 reported
shredding plants in 1971 to 144 in 1976. Many of these installations shred
prior to landfilling, since the Environmental Protection Agency considers that
landfilling of shredded refuse can be an environmentally acceptable disposal
method that reduces the need for daily soil cover and increases site life.
Several other installations shred in order to obtain a relatively homogeneous
waste stream more amenable to automated material handling and other processes
associated with resource recovery, incineration, or the preparation of refuse-
derived fuels.
This increased shredding activity has been accompanied by increased anxiety
about an inherent hazard in municipal refuse shredding. The heterogeneous
municipal solid waste mixture entering the shredder occasionally includes poten-
tially explosible materials such as flammable vapors, combustible dusts, and
commercial or military explosives. These materials can be ignited by impact
sparks or hot spots occurring during the hammering or grinding operations within
the shredders. The resulting explosion may cause injuries or equipment damage
unless appropriate explosion protection measures are implemented.
Factory Mutual Research Corporation (FMRC) recently conducted a refuse
shredder explosion hazard assessment for the Energy Research and Development
Administration. The hazard assessment included a survey of explosions that
have already occurred at refuse shredding plants, and an analysis of alternative
explosion protection techniques available to shredder manufacturers and/or
operators. The results of that study are summarized in this paper. The complete
(4)
report can be obtained from the National Technical Information Service.
The FMRC survey of shredder explosions was primarily concerned with the
conventional hammemills and grinders commonly employed in municipal solid
waste (MSW) plants. Rogers and Hitte^ ' and Robinson ' have recently pre-
sented comprehensive descriptions of hammermills and grinders, as well as other,
less common, refuse shredders. The shredder explosions documented in the FMRC
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survey were those that either caused damage or required the activation of a pro-
tection system (e.g., explosion vents) to avoid damage. Thus, we excluded minor
"pops" due to aerosol cans and other materials that are more a nuisance than
bona fide explosions. The only exceptions to this definition were a few cases
in which explosions were included that did not cause any physical damage, but
whose blast caused severe vibration of the building and shakeup of the plant
operators.
A total of 95 explosions in mixed MSW shredders were reported during the
course of the FMRC survey. (Since the survey was completed, this author has
learned of several other shredder explosions, putting the current total at well
above 100.) The distribution of reported explosions among the three major types
of shredders is listed in Table I. It is apparent that grinders, horizontal
shaft hammermills, and vertical shaft hammermills have each experienced a sig-
nificant number of explosions that is consistent with the relative populations
of shredder types in operation.
Although shredder explosions are numerous, the damage and injury potential
from any single explosion is limited by the structural integrity of the shredder.
Only three of the reported explosions have resulted in any personal injuries and
those three involved plant personnel in the immediate vicinity of the shredder.
Damage within the plant is usually associated with peripheral equipment such as
ducts or conveyors, which are not as explosion resistant as the sturdy shredders.
Figures 1 and 2 show the damage incurred by a conveyor following one of the more
severe shredder explosions. Only five (5.3 percent) of the reported explosions
have resulted in more than $25,000 property damage or caused the shredder to be
inoperable for more than a week.
The reported intervals between shredder explosions were also documented In
the FMRC survey in terms of both time and solid waste throughout. The average
reported throughout between explosions was 85,000 tons. However, the newer
MSW plants that had shredded less than 50,000 tons (and, therefore, had better
recall of explosions occurring) reported an average interval of 20,000 tons
processed between explosions. It is clear from these numbers that operators
of large MSW shredding installations can expect to encounter several explosions
during the lifetima of the plant. The types and quantities of materials that
are responsible for these explosions are discussed in the following section.
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FACTORY MUTUAL RESEARCH CORPORATION
TABLE I
DOCUMENTED EXPLOSIONS IN DIFFERENT TYPES OF SHREDDERS
Shredder
Type
Vertical
Grinder
Horizontal
Hammermill
Vertical
Hammermtll
Total
Number of
Locations
8
24
15
47
Number of
Shredders
11
38
17
66
Number of
Explosions
24
47
24
95
TABLE II
MATERIALS RESPONSIBLE FOR REPORTED SHREDDER EXPLOSIONS
Commercial or
Flammable Military
Vapors & Gases Explosives
Undetermined Total
Number of Explosions
30
11
54
95
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FACTORY MUTUAL RESEARCH CORPORATION
FIGURE 1 DAMAGED CONVEYOR FOLLOWING SHREDDER EXPLOSION
FIGURE 2 CLOSE-UP OF DAMAGED CONVEYOR
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POTENTIALLY EXPLOSIBLE MSW MATERIALS
Common sense dictates that explosives such as dynamite, TNT and gunpowder,
should not be shredded because of the obvious explosion hazard. However, even
if these materials can be completely removed from the shredded waste stream,
there are a variety of flammable liquids, gases, and dusts which will invariably
be present in refuse shredders.
Table II is a compilation of the different types of materials responsible
for the shredder explosions reported during the FMRC survey. Only 11.6 percent
of the reported explosions were attributed to identifiable commercial or mili-
tary explosives. The large majority of explosions were either attributed to
flammable vapors/gases or were of undetermined origin. Since many common flam-
mable vapors may not be recognized by shredder operators as explosible materials,
many of the explosions of undetermined origin may also have been due to flammable
vapors.
Flammable Vapors and Gases
Table III contains representative explosibility data for ten common flam-
mable gases and vapors that may occasionally appear in MSW shredders. The
flash points listed in Table III are the minimum temperatures at which enough
vapor is evolved to form a flammable mixture within the shredder. Since tem-
peratures in an operating shredder are probably higher than 100CF, all of
the vapors in Table III are capable of forming explosible gas-air mixtures*
in the shredder.
The vapor concentration at the flash point is the lower flammable limit -
also listed in Table III. The other end of the flammability range is the upper
flammable limit - defined as the maximum vapor concentration capable of sustain-
ing flame propagation through gas-air mixture. Although any vapor concentration
between the lower and upper flammable limits corresponds to an explosible mix-
ture, the most violent explosions are usually associated with nearly stoichio-
metrlc mixtures. A stoichlometric mixture is defined as one in which there is
just enough air and fuel for the combustion reaction to be completed with no
*Even if the liquid temperature is below the flash point, flammable liquids
dispersed in the form of a fine mist or spray can undergo explosions.
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FACTORY MUTUAL RESEARCH CORPORATION
TABLE III
EXPLOSIVE PROPERTIES OF COMMON FLAMMABLE VAPORS AND GASES
Gas/Vapor
Acetone
Benzene
Ethyl Alcohol
Gasoline
(100 octane)
Isopropyl
Alcohol
Methane
Naphtha
Propane
Toluene
Turpentine
Common
Household
Uses/Products
Paint Solvent
Paint Thinner
Liquor, Cologne
Motor/Lawn-
mower Fuel
Rubbing
Alcohol
Refuse Decompo-
sition Gas
Lighter Fluid
Charcoal Fluid
Fuel Gas
Paint Thinner
Paint Cleaner
Flash
Point*
(°F)
0
12
55
-45
53
Gas
28-85
Gas
40
95
Flammable Limits
(vol %)**
Lower - Upper
2.6 -
1.3 -
3.3 -
1.4 -
2.2 -
5.0 -
0.9 -
2.1 -
1.2 -
0.7 -
13
7.9
19
7.4
15
6.7
9.5
7.1
P ** K **
max G .
(psig) (psi-ft-sec )
83
97
99
-
92
-
94
96
92
-
1410
1625
1770
—
1340
-
1770
1770
1700
-
* from reference 6
** from reference 7
*** from Table 3 in reference 8
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remaining gaseous fuel or oxidant. The stoichiometric concentrations of the
vapors listed in Table III are equal to approximately twice the lower flammable
limit concentrations.
The other two parameters in Table III, P and K , refer to explosions of
approximately stoichiometric gas-air mixtures in closed vessels. P is the
max
maximum pressure developed in the explosion, and K is defined to be
V1/3 (1)
where —I is the maximum rate of pressure rise and V is the vessel volume.
The valuesmS? P and K lie in relatively narrow ranges for the flammable gases
max u
and vapors listed in Table III. Two gases with significantly larger values of
P and K- are acetylene and hydrogen. They were not included in Table III be-
max la
cause they are not as likely to appear in municipal refuse. However, should they
get into a shredder (acetylene was suspected in one reported shredder explosion)
they are capable of producing more violent explosions.
The maximum pressures and rates of pressure rise indicated in Table III
refer to deflagration type explosions. The flame propagates through the unburned
gas-air mixture at subsonic velocities (of the order of 1-10 ft/sec) in a deflag-
ration, whereas it propagates supersonically in a detonation. The distinction is
important since during a detonation the pressure rises virtually Instantaneously
(as soon as the shock wave arrives at a given location) and there is no time to
take corrective action before the explosion is consummated. Most shredder explo-
sions involving the flammable gases or vapors in Table III are probably defla-
grations because detonations require either explosive ignition sources or a
tubular (or ductlike) geometry.
Most MSW shredders would be damaged beyond repair when subjected to the
peak pressures shown in Table III (83-99 psig). These pressures refer to a
closed vessel completely filled with an optimum gas-air mixture. For a typical
shredder volume of 1600 ft (including inlet hood), a stoichiometric mixture
would require about 1.7 gallons of gasoline to be vaporized and mixed with the
air in the shredder. Comparable volumes would be required for the other volatile
liquids listed In Table III. Vapor volumes and mixtures of that size are
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certainly possible but a more likely scenario is for only a portion of the shred-
der to be occupied by a flammable mixture at ignition.
Figure 3 can be used to estimate the maximum pressure developed in an explo-
sion involving a local pocket of flammable gas/air mixture of approximately
stoichiometric proportions. The data and theoretical curve in Figure 3 refer
(9)
to a propane/air mixture. According to the theoretical model of the adiabatic
compression of a oerfect gas, the results in Figure 3 should be applicable to
all gas mixtures having the same value of the ratio (M T,)/(M. T ). The sym-
bols M and T denote mixture molecular weight and temperature, and the subscripts
u and b refer to unburned and burned gas, respectively. This ratio is also equ.il
to the theoretical ratio of the maximum pressure to initial pressure for a
(9)
deflagration in a completely filled vessel . Since the values of P for the
max
fuels, including propane in Table III do not differ by much (P =91+8 psig),
we expect the curve in Figure 3 to also be approximately valid for all of these
fuels.
Since the pressures in Table III and in Figure 3 pertain to closed vessels,
they provide conservative estimates of the pressures developed in partially
vented shredders. A quantitative discussion, of the relief provided by venting
is presented in the discussion of alternate protection measures. Nevertheless,
it is interesting to use the data in Figure 3 to estimate the amount of flam-
mable gas/vapor required to produce significantly high pressures in a structure
the size of a typical shredder.
According to Figure 3, flammable mixture volumes equal to 10 percent of
the shredder volume are capable of producing overpressures of about 10 psi in a
completely enclosed hammermill. Based on damage estimates from some of the
explosion reports, it appears that pressures of 7-10 psi will initiate major
damage to discharge hoods, door latches, and other peripheral equipment. Thus,
damaging explosions can result from as small a volume as 0.17 gal of gasoline
completely vaporized and mixed in stoichiometric proportion with 10 percent
of the air in a 1600 ft shredder. Discarded containers containing at least
that quantity of gasoline, paint thinner, charcoal lighter fluid, etc. must
appear often in MSW shredder input streams. It is no wonder that a large frac-
tion of the reported shredder explosions were due to such flammable vapors and
gases.
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o
o
I I I I I i 11 I i i i i i i i 11 i
- aansssHd NOisoidxa wnwixvw
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Commercial and Military Explosives
Carelessly or surreptitiously discarded explosives, such as gunpowder, dyna-
mite, and military ordnance, occasionally appear in MSW shredding plants. Many
of these explosives can be triggered by impact, friction, sparks, or hot spots
present during shredding. Shredder explosions caused by these materials are
more difficult to control than flammable vapor explosions because 1) explosives;
contain their own oxidant and need not vaporize and mix with air to form an ex-
plosive mixture, and 2) the resulting explosion is often a detonation rather
than a deflagration.
Laboratory tests to determine explosive sensitivity have been conducted for
the more common explosive materials. Interpretation of this test data, indicates
TNT, will also detonate when triggered by the lead azide primer, which is particu-
larly impact sensitive. The sensitivity of smokeless gunpowder is strongly in-
fluenced by its moisture content.
Reports of the shredder explosions due to dynamite and military ordnance
indicate that blast waves, characteristic of detonations, occurred. There has
been one documented shredder explosion caused by smokeless gunpowder, but it waa
not one of the more violent explosions. This is probably because gunpowder is a
low-order explosive, tending to produce deflagrations. The explosive yield and
TNT equivalence of various explosives in Table IV can be found, for example, in
Baker's text.(10)
Combustible Dusts and Hybrid Dust/Gas Mixtures
Although none of the reported shredder explosions were unequivocally attribu-
ted to combustible dusts, there is speculation that some of the explosions of
"undetermined cause" may have actually been caused by a combustible dust cloud.
If some explosions at shredding plants are indeed caused by dust, they are more
likely to originate in dust collecting equipment rather than the shredder itself.
This is because a bona fide dust explosion can only occur if the dust particle
size is small enough to be classified as a powder, i.e., much smaller than 1 mm.
Thus, Palmer, in discussing the explosion hazard of grinding machines (Reference 11,
p. 300), states that "the explosion risk is low for those crushers delivering
product of a few centimeters (1 in.) diameter," which is a typical average
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particle size for'MSW shredder output. Palmer warns, however, that precautions
should be taken to prevent the small proportion of powder produced In the crush-
ing process from accumulating In a confined area.
Palmer's speculation and admonition Is consistent with the results of the
(12)
FMRC survey of shredder explosions. In the one report where there was any
real evidence of a dust explosion, the explosion originated in a small separate
structure through which the shredded refuse was conveyed. Apparently, dust was
allowed to accumulate in the conveyor house, and a friction spark set off the
explosion which destroyed the concrete structure. Photographs illustrating the
damage Incurred in this incident are shown in Figures 4 and 5.
It is very likely that, upon occasion, combustible dust and flammable gas
or vapor will be present simultaneously in a refuse shredder. These so-called
hybrid mixtures are particularly hazardous because they can be explosive even
when the Individual gas/air and dust/air constituent mixtures are not explosible.
(14)
For example , a methane concentration of 1 vol percent in air is below the
lower flammable limit, and PVC dust consisting of particles with a diameter of
100 microns will not explode in any concentration. However, when the two are
combined, an explosible hybrid mixture results that can develop a maximum pres-
sure of about 8 bars (118 psi) at a PVC concentration of 100 gm/m .
It is particularly noteworthy that small quantities of methane can con-
tribute to explosible hybrid mixtures. The refuse decomposition process which
produces methane ia a relatively slow one (landfills require about six months
to generate collectible quantities of methane), probably too slow to produce
enough methane to form a flammable methane/air mixture in a shredder. However,
it may be possible for small quantities of methane to combine with accumula-
tions of fine combustible dust to form an explosible hybrid mixture in the
shredder.
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FACTORY MUTUAL RESEARCH CORPORATION
FIGURE 4 EXPLOSION AT VOLUME REDUCTION PLANT. SHREDDER
BUILDING AT RIGHT. COMPACTOR BUILDING AT LEFT.
(Reference 12)
FIGURE 5 REMAINDER OF REAR WALL OF CONVEYOR BUILDING NEAREST TO
SHREDDER PLANT (Reference 12)
-------
EXPLOSION PROTECTION MEASURES
Explosion protection consists of preventive measures and damage control
techniques. Although prevention is preferable to damage control, it is un-
realistic to expect currently available preventive measures to eliminate all,
or even most, shredder explosions. Manual and automatic shredder input screen-
ing and other preventive measures are discussed in this section, but primary
emphasis is placed on damage control measures.
In assessing the potential effectiveness of damage control techniques,
It is important to differentiate between detonations and deflagrations. The
local overpressurization in a detonation occurs instantaneously via shock wave
propagation, but the overpressurization in a deflagration occurs over a time
interval on the order of 0.1 - 1.0 sec in a typical size shredder. Most of
the protective measures discussed herein should be effective for incipient
deflagrations, but cannot be expected to provide much protection for detona-
tions. The two exceptions are isolation and blast resistant construction.
Since most shredder explosions are deflagrations, all of the protection meas-
ures are worthy of consideration.
Preventive Measures
To prevent an explosion, either the ignition source, the explosive material,
or, (for combustion type explosions) the oxidant must be removed. In hammermills
and grinders, ignition sources include impact sparks, friction sparks and local
hot spots. These sparks and hot spots are inevitable with the metal hammers
and grinder rings used today. Some radically different hammer/grinder material
or coating would be required to eliminate all ignition sources, and no such
development seems to be imminent.
Inerting to reduce the oxygen content does not appear any more promising.
Refuse shredding operations currently are continuous processes involving large
openings to the atmospheric at the inlet and outlet. Inerting would require
either completely closing the shredder openings or else providing a continuous
source of inert gns. Neither technique appears to be economically feasible.
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The other preventive measure, removal of explosible material, involves
either manual or automatic screening of shredder input materials or continu-
ous purging of explosible material in the shredder. Manual screening is already
a common practice. Obviously explosive materials, as well as difficult-to-shred
items, such as rolled-up carpets, cables, and large tree limbs, are removed
from the tipping floor or the shredder input conveyor. Manual screening is
necessary but cannot be relied upon to remove the entire gamut of potentially
explosible items. A possible improvement in manual screening efficiency might
be achieved by indoctrinating refuse plant and collection personnel in the
potential explosion hazards of the seemingly innocuous flammable vapors dis-
cussed previously.
The use of automatic detectors to screen various explosive materials is
possible in principle, but its feasibility is questionable. Vapor detectors
placed upstream of the shredder would have to be extremely sensitive to detect
the presence of flammable vapors or explosives still contained in their package.
Vapor detectors placed within the shredder would only be useful if they triggered
some active suppression or inerting system, since most shredders require several
minutes to come to a halt. In either case, the detector would have to be in-
vulnerable to false alarms caused by a variety of non-explosible vapors, and
would also have to resist deterioration in a rugged, dirty environment. Cur-
rently available commercial detectors do not meet these stringent constraints
(reference 4, pp 51-52). Thus, automatic screening of potentially explosive
materials is not a realistic alternative in the near future.
Continuous purging of explosible materials by utilizing large air flow
ventilation rates has also been considered. To be effective, the air flow rate
must be large enough to dilute or remove the flammable vapor (or dust) before
it mixes with air and encounters an ignition source. Vapor mixing and spark
ignition sources, i.e., hammer impacts, are both related to shredder shaft ro-
tation, so the characteristic time for these processes is the reciprocal of
shaft RPM, K. The characteristic time for diluting/removing the vapor in the
shredder is V/Q, where V is the shredder volume (ft ) and Q is the air flow
rate (cfm). Thus, if the vapor is to be swept out before it forms a flammable
mixture and ignites, the ratio Q/VH should be larger than unity. However, for
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the typical values, Q = 10,000 cfm, V = 1,000 ft3, £2 = 1,000 RPM, this ratio
_2
is 10 , two orders of magnitude too small to rely on continuous purging as a
preventive measure. We conclude that purging, like the other preventive measures,
may be helpful, but does not provide a foolproof safeguard against explosions.
Explosion Venting
The basic concept of an explosion venting system is that the maximum pres-
sure developed in a deflagration can be greatly reduced if the burned and un-
burned gases are allowed to escape from the confining structure before the com-
bustion process is completed. This can be achieved by providing vent doors,
blow-off panels, rupture discs, etc., on the equipment or building containing
the explosion. To be effective, the vent area, inertia, release pressure,
and proximity to the ignition source must be adequate to allow the gases to es-
cape before damaging overpressures are generated. Furthermore, any ducting em-
ployed to channel the gases out of the surrounding building must avoid a recom-
pression of the gases on their way out.
Most refuse snredders currently in use do not have adequate explosion vent-
ing provisions. Those shredders that are outfitted with explosion vents usually
have undersized vents (according to the guidelines discussed in this section)
that are often located too far from the ignition source, ±. ., the hammers,
to be effective. This is particularly true when inlet and discharge openings
and reject chutes are relied upon for venting. These openings are usually too
obstructed with refuse and debris to provide a large enough outflow rate for
the vented combustion gases.
During the past few years, several different quantitative explosion vent-
ing guidelines have been proposed for gas and dust explosions in process equip-
ment. These guidelines, which are prescribed in references 8,9 and 13-17
describe how a vent system can be designed for a given combination of fuel/
oxidant mixture, ignition source, and restraining vessel. Most of these guide-
lines have been developed from tests in spherical, cubical, cylindrical, or
other simple shaped vessels of various sizes ranging from laboratory scale to
60 m . They have not been verified for equipment as complicated in shape and
contents as a refuse shredder. In particular, internal equipment and refuse
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within the shredder are likely to obstruct the flow of vented gases and thus
produce significantly higher pressures than are measured in similar sized
vessels free of obstructions. Furthermore, there are sometimes large discrepan-
cies between the various venting recommendations.
Since none of the quantitative explosion venting guidelines have been
verified by tests simulating shredder explosions caused by flammable gases or
vapors, no single guideline can be decreed to be most applicable for shredder
explosions. The general procedure for using the guidelines for gas explosions
will be reviewed here and a comparison of predicted vent areas for three dif-
ferent shredders will be presented. The guidelines will be applied for a
worst-case, near stoichiometric propane-air mixture, since propane is repre-
sentative of the flammable gases expected in a refuse shredder (Table III),
and much of the available venting data was obtained with propane.
An essential parameter in all of the recent guidelines is the quantity
AP , which is the maximum tolerable overpressure for the equipment (includ-
m&x
ing ducts, hoods, etc.) containing the deflagration. The appropriate value of
AP should be specified by the equipment manufacturers on the basis of test-
ing or structural analysis. Inquiries to shredder manufacturers, however,
have indicated that they are unaware of what the value of AP , should be for
ngf*
their equipment. Therefore, observations and measurements of damage in-
curred during several shredder explosions will be used as the basis for esti-
mating AP . These observations indicate that appreciable damage to peripheral
equipment occurred at overpressures of about 5-7 psig. The recommendations
presented here (Table IV) correspond to AP =4.4, which was a convenient figure
to use in one of the guidelines, and also provides a small measure of conserva-
tism, i.e., safety.
Another parameter in the venting guidelines is P , the pressure at which
the vent is opened. P should be considerably less than AP because 1) the
maximum pressure in a vented deflagration is often larger than the vent release
pressure, and 2) most industrial buildings containing, or adjacent to, shred-
ders will fail at overpressures well under 5-7 psig. In the following examples,
P is set equal to 1.45 psig because this is the lowest value of P in some of
the venting correlations.
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The turbulence level* in the vessel is still another pertinent factor in
the explosion venting guidelines. In some guidelines * the turbulence level
is an on-versus-off factor, i.e., agitated gas versus quiescent gas, while in
other guidelines ' the turbulence level is specified as some multiple of
the fundamental laminar burning velocity of the gas-air mixture. In both cases,
the required vent area to achieve a specified peak pressure is larger for a
turbulent gas mixture, such as would be expected in a shredder, than for an
initially quiescent mixture in which laminar flow prevails throughout the vent-
ing process.
Once the combination of shredder volume, maximum tolerable overpressure,
worst-expected-caoe fuel/air mixture, desired vent release pressure, and turbulence
level have been ascertained, the explosion venting correlations in references 2,9,
and 13-17 can be utilized to determine the required vent area. This has been
performed for the three representative shredders listed in Table IV. The recom-
mended vent areas shown in Table IV are slightly larger than the values originally
given in Table XII of reference 4, because the values shown in Table IV were
(19-21)
calculated using new data on turbulence effects that have become available
since the report was written. The new data indicate 1) that the most appropri-
ate value for the ratio turbulent/laminar burning velocity factor appearing in
the Yao correlation is x-4 and 2) that the turbulent value of K (defined in
b
eq (1)) for propane appearing in Bartknecht's nomograms is 5.5 times the
laminar value indicated in Table III.
Although there have not been any shredder explosion tests with gaseous
fuels to verify the validity of the vent areas recommended in the various guide-
/T O \
lines, Scholl has recently conducted some dust explosion tests. The tests
were conducted in an older version of a HAZEMAG horizontal hammermill and were
primarily sponsored by HAZEMAG Germany. Most of Scholl's tests were designed
to evaluate various explosion suppression configurations, but he also conducted
some explosion venting tests.
Figure 6 is a schematic illustration of the dust dispersion arrangement
and instrumentation employed by Scholl. Four different dusts (coal dust,
*Turbulence level here refers to both the pre-ignition state of the gas and to
the turbulence developed by the vented gases.
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FACTORY MUTUAl RESEARCH CORPORATION
TABLE IV
COMPARISON OF RECOMMENDED VENT AREA
CORRELATIONS APPLIED TO THREE HAMMERMILLS
Recommended Vent Area (ft )
Shredder NFPA 68* Yao** Bartknecht***
Williams Model 680*494558.1
(Horiz. Hamuermill + Inlet Hood,
Volume -150C ft3
L/D = 3)
Modified Hazemag** 57.8 50.8 73.2
(Horiz. Hammermill,
Volume -1800 ft3
L/D = 2)
Heil Model 42D 12.3 9.7 11.8
Vertical Hammermill,
Volume -150 ft3
L/D = 2)
* Based on Table 2, pp 68-36, reference 8
** from Figure 11 of reference 16, for x=4
*** from Figure 10 of reference 14, adjusted to account for turbulent
value of K
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V, « 14.3 m3
V2- 3.3m3
V3« 0.8m3
V4» 2.6m3
V8- 8.0m*
Rotor
--> St3
'. ! ! 1st
.
1+2
|V*
rt
F « Open Area (Ffot(ri-5.8m2)
Z = Ignition
St * Dust Disperiol Orifice
P * Presture Transducers
FIGURE 6 SCHEMATIC DRAWING OF HORIZONTAL HAMMERMILL USED IN
SCHOLL'S DUST EXPLOSION TESTS; TOTAL VOLUME = 29 m3.
(From Reference 18 , Figure 5)
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polyester, "Hexa", and "Sirona") were tested with a spark ignition located
near the rotor. Pressures were measured in the mill and in the inlet and dis-
charge hoods. The objective of the tests was to find some suppression and/or
venting arrangement that would keep the pressures within tolerable levels and
also prevent flame propagation through the inlet and discharge hoppers.
In order to obtain an adequate vent area in the vicinity of the ignition
source, i.e., the rotor, Scholl eventually modified the hammennill as shown
in Figure 7. The results obtained with the modified vented hammennill are
2 2
shown in Table V. When the vent area was increased from 10.8 ft to 64.6 ft ,
the mill pressure was reduced from 3.7 psig to 0.7 pslg in the test series with
Sirona dust. A significant reduction in pressure was also obtained with Hexa
dust when the vent area was increased from 21.6 ft to 64.6 ft .
The flame duration times indicated in Table V indicate that venting alone
cannot be expected to prevent flame propagation into and through the shredder
inlet and outlet areas. Therefore, the vented gases should not be discharged
into a space containing personnel or unprotected equipment. If the shredder
is located inside a building, it is often necessary to provide a vent duct to
channel the vented gases out of the building.
If a vent duct is employed, the vent must be designed to prevent a re-
compression of the vented gases and a possible escalation of the deflagration
(14)
into a detonation. Bartknecht recommends that the vent duct for typical
granulators be less than 6 m (19 ft), and, if its length is in the range 3-6 m,
the maximum pressure can be increased substantially over the equivalent un-
/Q \
ducted situation. The NFPA guidelines suggest that, if any appreciable duct
length is required, the cross-sectional area of the duct should be at least
twice that of the vent device. Furthermore, the duct should not have any
bends including the junction with the shredder.
Several refuse shredder installations already employ vented ducts and/or
blow off panels on the walls of the shredder building. Figure 8 shows such
an installation in which one vent duct attached to the shredder led to two
heavy hinged doors on the roof of the building. Unfortunately, the doors were
too heavy to open fast enough, and were blown off their hinges as a result of
the explosion. The ducting and roof vent have since been replaced with a diverg-
ing duct and a lighter roof vent.
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Vent Area
1-6 m2
Inlet Hood Lengthened
One Impact Plate Removed
FIGURE 7 MODIFIED HAMMERMILL USED IN SCROLL'S EXPLOSION VENTING;
TOTAL VOLUME = 51 m3. (From Reference 18 , Figure 34)
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FACTORY MUTUAL RESEARCH CORPORATION
TABLE V
SCHOLL'S DUST EXPLOSION VENTING TEST RESULTS
(from Reference 18)
Dust Type Vent Area Pffiax Flame Duration
(ft2) (psig) (sec)
SlronaIO 57? 174
" 21.6 2.6 3.2
64.6 0.7 0.7
Hexa 21.6 2.8 8.6
" 64.6 1.6 4.7
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FACTORY MUTUAL RESEARCH CORPORATION
FIGURE 8 SHREDDER BUILDING FOLLOWING EXPLOSION
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Several other damaging explosions in inadequately vented shredders have
demonstrated the need for improved venting guidelines applicable to shredder
operations. A test program similar to the one conducted by Scholl, but employ-
ing flammable gases, would be extremely useful in generating the data required
for such improved guidelines.
Explosion Suppression System
The basic premise of an explosion suppression systeir is that the maximum
pressure and flame propagation can be reduced to tolerable levels if a suitable
extinguishing agent is injected quickly enough into an incipient confined gas
or dust deflagration. An inherent advantage of a successful suppression systeir
over an explosion venting system is that the flame will be extinguished in the
shredder, so that the post explosion fire hazard is eliminated.
Various types of explosion detection devices (ultraviolet, infrared, thermal,
and pressure) cau be employed to actuate the suppression system, but the one
usually employed in the dirty, obstructed shredder environment is a fast-response
pressure transducer. The actuation pressure of the detector must be low enough
to allow for early introduction of the extinguishing agent, but high enough to
avoid false alarms due to slight pressure transients under normal operation.
For shredders, the actuation pressure is usually in the range 0.5 - 1.5 psig
depending on the extinguishing agent used.
The explosion suppression agents most commonly employed in the United States
are the halogenate.d hydrocarbons (Halons). The Halons are believed to chemically
inhibit the combustion process. The Halons used for explosion suppression appli-
cations are bromochloromethane (Halon 1011, CB), Halon 1301 (CF Br), and
Halon 2402 (C_F Br ). Fenwal, Inc., which is the only American manufacturer
of commercial explosion suppression systems, recommends Halon 1011 for use in
hammermills and grinders. The concentration of CB recommended by Fenwal is
25 liquid cc's per ft of vessel volume.
The explosion suppression agents favored in Germany are the chemical
extinguishing powdsrs, amnsnium phosphate and sodium bicarbonate. Tests con-
(1'^ 14)
ducted by Bartknecht * indicate that these powders are effective even at
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relatively high actuation pressures, i.e., when the deflagration process is
well underway. Thus, powder suppression systems seem to be less susceptible to
false alarms than are Halon systems. Bartknecht provides recommended concen-
trations of extinguishing powder for various combustible gases and dusts and for
different actuation pressures in references 13 and 14. Results of recent
(19)
Coast Guard tests in large obstructed enclosures also indicate that the mini-
mum required ageut concentrations (mass of agent per unit enclosure volume) for
successful suppression are lower for dry chemical powders (Purple K) than for
Halons.
No matter which agent is deployed, the effectiveness of an explosion sup-
pression system is limited by both the detection time and the travel time for
dispersing the agent into the unburned-fuel/air mixture. Thus, fuel/air mixtures
with exceptionally fast burning velocities and rates of pressure rise cannot be
extinguished early enough to provide proper protection. For successful suppres-
(19)
sion of propane/air mixtures, the Coast Guard tests indicated that Halon
agents must be completely dispersed within 150 millisec after ignition. Fuels with
faster burning rates (or larger values of K_), e.g., acetylene, would require
G
shorter detection/dispersal times*.
Although there have been no shredder explosion tests with gaseous fuels,
(18)
Scholl's explosion suppression tests have recently provided a quantitative
measure of the effectiveness of the German suppression system for dust explo-
sions. The haitimermill used in Scholl's first series of suppression tests is
the one shown in Figure 6. The results obtained by Scholl for polyester dust
explosions with and without a suppression system are given in Table VI. The
suppression system arrangement used in this test series consisted of 14 agent
containers uniformly distributed throughout the hammermill. It is clear from
Table VI that the suppression system reduced the peak pressures significantly
below the corresponding unsuppressed case. Furthermore, the flame duration
times in the shredder inlet and outlet were reduced by an order of magnitude
with the suppression system.
*The critical detection/disposal time also depends upon shredder volume, V,
since the time
(reference 13).
since the time at which a given overpressure is developed is proportional to V
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FACTORY MUTUAL RESEARCH CORPORATION
TABLE VI
SCROLL'S DUST EXPLOSION SUPPRESSION TESTS
(from Reference 18)
Polyester Dust
Concentration
(gm/m )
250
500
250
500
P
max
(psig)
5.9*
8.1*
3.7
5.1
Flame
Duration
(sec)
4.8
>6.1
0.25
0.35
Suppression
System
No
No
Yes**
Yes**
* Outlet hood was bent and rubber curtain at inlet blew away in these tests.
** The suppression system used in these tests consisted of 14 kg bottles of
dry chemical suppression agent installed throughout the mill and activated
at an overpressure of 1.5 psi.
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Scholl also made two significant observations about the disadvantages of
using a suppression system with an actuation pressure of 1.5 psig: 1) he
observed that relatively mild deflagrations, such as were obtained using coal
dust, produced maximum pressures below the actuation pressure. Therefore,
the agents were never discharged and flames propagated through the hammermill;
2) the same result occurred when a large vent area was used in conjunction with
the suppression system to minimize overpressures. Thus, venting and suppression
are incompatible unlass the vent relief pressure is significantly higher than
the suppression actuation pressure.
Fenwal suppression systems with Halon 1011 agent actuated by pressure trans-
ducers triggering at 0.5 psig and at 1.5 psig have been installed during the past
year at several shredding plants. There have been several successful actuations
and suppressions. There has also been one incident in which some damage was
incurred, but the material causing that explosion was not determined.
Water Spray
A continuous water spray is used in several refuse and automobile shredders
primarily to reduce the suspended dust level. These shredders have experienced
significantly fewer damaging explosions than shredders operating dry.
A fine water spray or mist can prevent or mitigate explosions through the
following mechanisms: 1) the water droplets can quench, or at least decelerate,
the incipient flame; 2) air entrained into the water spray may dilute the flam-
mable mixture more efficiently than forced ventilation; 3) the water vapor
represents an inerting agent slowing down the combustion reaction; and 4) some
flammable gas may be removed by adsorption onto the water droplets.
Our current understanding of these mechanisms is not sufficient to specify
the water flow rates and drop sizes needed for successful suppression/prevention.
One shredder installation that has experienced some success* with a water spray,
utilizes a flow rate of A gal/min for four shredders and ducting with a total
volume of 18,000 cu ft. Although large water flow rates are desirable for
explosion mitigation, they can cause such deleterious side effects as corrosion,
*The water spray seems to have reduced both the frequency and severity of
explosions in this plant.
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increased particle size of shredder output, and high moisture content in shredder
output. More testing and operating experience is needed before the optimum com-
bination of water flow rate and drop size, i.e., nozzle type and pressure, can be
determined.
Miscellaneous Protection Measures
One of the simplest and most effective injury prevention techniques is
isolation. Plant personnel should not be near the shredder while it is opera-
ting. One of thfi injuries reported in the shredder explosion survey occurred
in a plant where the control room is only about 10 ft from the shredder. In
plants where the control room is immediately adjacent to the shredder, it is
important to use high-strength glass (> 3 psig fracture pressure) in the control
room window.
If personnel or valuable equipment must be located near the shredder, the
use of barricades or blast mats should be considered. The barricades should
be designed to deflect an impinging blast wave and also prevent penetration
by missiles (fragments) caused by the explosion.
CONCLUSIONS
There have been over 100 reported refuse shredder explosions in which some
damage was incurred or which caused the activation of some explosion protection
measure. 76 percent of the shredding installations surveyed, have experienced
at least one explosion. Although the responsible material was not identified
in the majority of explosions, flammable gases and vapors are often involved.
Damaging overpressures can be produced from as little as 1/4 gal of gasoline,
paint thinner, etc. in a shredder of typical size. Commercial and military
explosives such as dynamite and gunpowder have also been responsible for some
explosions.
Because of the wide assortment of potentially explosible material in mixed
municipal refuse, preventive measures such as manual or automatic screening of
shredder input cannot be expected to eliminate explosions entirely. Instead,
emphasis should be placed on damage control measures. Explosion venting,
explosion suppression systems, and water spray all show promise for mitigating
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the effects of deflagration-type explosions associated with most flammable vapors.
However, tests and additional operating experience are needed to determine
whether existing design guidelines for these systems are applicable to the
complicated shredder environment. For detonation-type explosions caused by
most commercial and military explosives, isolation of the shredder and the use
of blast mats or barricade appear to be the only feasible damage/injury con-
trol measures.
ACKNOWLEDGMENTS
The author is grateful to Messrs. D.E. Patterson and A.A. Weintraub of the
Energy Research and Development Administration for initiating and supporting
this work under Contract No. E(49-l)-3737. Thanks are also due to
S.A. Wiener and J.L. Buckley of Factory Mutual Research Corporation for their
contributions during the course of the study.
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REFERENCES
1. Anonymous, "Solid Waste Shredding: Blueprint for Progress,"
Waste Age, vol 6, pp 10-15, July 1975.
2. Anonymous, "Solid Waste Shredding: Continued Growth in Waste Processing,"
Waste Age, vol 7, no. 7, pp 34-40, July 1976.
3. Rogers, H.W. and Hitte, S.J., "Solid Waste Shredding and Shredder Selection,"
Environmental Protection Agency Report EPA/530/SW-140, March 1975.
4. Zalosh, R.G,, Wiener, S.A., and Buckley, J.L., "Assessment of Explosion
Hazards in Refuse Shredders," Energy Research & Development Administration
report ERDA-76-71, 1976 (available from National Technical Information
Service, Springfield, Virginia 22161).
5. Robinson, W.D., "Shredding Systems for Mixed Municipal and Industrial Solid
Wastes," 1976 National Waste Processing Conference Proceedings,
Paper M4-C, ASME 1976.
6. NFPA No. 325M, "Properties of Flammable Liquids," 1969, available from
National Fire Protection Association, Boston, Mass. 02210.
7. Zabetakis, M.G., "Flammability Characteristics of Combustible Gases and
Vapors," Bureau of Mines Bulletin 627, 1965.
8. NFPA No. 68, "Explosion Venting 1974," available from the
National Fire Protection Association, Boston, Mass. 02210.
9. Yao, C., de Ris, J., Bajpai, S.N., and Buckley, J.L., "Evaluation of
Protection from Explosion Overpressure in AEC Gloveboxes,"
FMRC Report RC69-T-23, 1969.
10. Baker, W.E., Explosions in Air, University of Texas Press, 1973.
11. Palmer, K.N., Dust Explosions and Fires, Chapman and Hall Ltd., 1973.
12. Burrill, W.G., Lucier, G.H., and Gaudreau, A.P., "Explosion-Fire
Investigation, Volume Reduction Plant, Milford, Connecticut,"
Intertech Corp. report originally submitted to
American Empire Insurance Co., 1974.
13. Bartknecht, W., "The Course of Gas and Dust Explosions and Their Control,"
Loss Prevention and Safety Promotion in the Process Industries,
pp 159-172, C.H. Buschmann, ed., 1974.
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14. Bartknecht, W., "Explosion Protection Measures On Fluidized Bed Spray
Granulators and Fluidized Bed Driers," lecture presented at
CIBA-GEIGY Corp., Ardsley, N.Y., October 1975, (translated by H. Burg).
15. Cubbage, P.A. and Marshall, M.R., "Explosion Relief Protection for
Industrial Plants of Intermediate Strength," Paper L in Inst. Chem. Engr.
Symposium Series No. 39, 1974, see also Inst. Chem. Engr. Symposium
Series No. 33, 1972.
16. Yao, C., "Explosion Venting of Low-Strength Equipment and Structures,"
Loss Prevention V_7 AIChE, 1973.
17. Howard, W.B. and Russell, W.W., "A Procedure for Designing Gas
Combustion Venting Systems," Paper K in Inst. Chem Engr. Symposium
Series No. 39, 1974.
18. Scholl, E.W., "Explosion Tests in a Refuse Shredding Mill,"
German Federal Institute for Labor Protection and Accident Investigation,
Dortmund, Research Report No. 124, 1974. (in German)
19. Richards, R.C. and Sheehan, D., "Explosion Suppression Systems for
Marine Applications," Offshore Technology Conference, Paper Number 2561, 1976.
20. Zaloah, R.G., "Explosion Protection Evaluation for the Brent B Offshore
Platform," Factory Mutual Research Corporation Report RC76-T-72, 1976.
21. Albrecht, A.R., Dow Chemical Co., personal communication and transmittal
of recent data obtained by W. Bartknecht, 1976.
22. Fenwal, Inc., "System Application Guide for Explosion Suppression
Systems," prepared by Fenwal, Inc., Ashland, Mass., 1973.
23. Nollet, A., AENCO Inc., personal communication, 1976.
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USE OF REFUSE-DERIVED SOLID FUEL
IN1 ELECTRIC UTILITY BOILERS
by Stephen A. Lingle and J. Robert HoTtov;ay*
Summary
Processing of municipal solid waste to produce products which can
be used as supplemental fuels is one of the major alternatives for
simultaneous disposal of solid waste and recovery of energy. This
technology involves physical or chemical processing of municipal solid
waste to produce solid, liquid, or gaseous products called refuse-
derived fuels. Most of the attention to date has been on refuse-
derived soJJ_d_ fuels, commonly called RDF. Solid RDF can be produced
by physically processing solid waste through size reduction and
density classified ion. The RDF can then be sold to users v.'ho have
existing boilers for use as a supplement to fossil fuels to generate
steam or electricity.
Since successful demonstration of this concept by the City of
St. Louis, the Union Electric Company and the U.S. Environmental
Protection Agency, it has been met by a rush of interest and enthusiam
by cities. By the end of this year, a total of four commercial facilities
will have been constructed, and at least four more are considered
committed. Many other cities are involved in feasibility studies.
Although actual operating experience is very limited, there seems
to be a feeling that questions and problems relating to production of
RDF can be worked out. However, cities may face a significant problem
in obtaining firm, long-term markets for the RDF with guaranteed minimum
revenues. Thus, the ability to market RDF appears to be the most critical
issue affecting the future of this recovery approach.
* Stephen A. Lingle, Chief, Technology & Markets Branch, Resource
Recovery Division, Office of Solid Waste Management Programs, U.S.
Environmental Protection Agency, presented this paper at. the Fifth
National Congress on Waste Management Technology and Resource Recovery
sponsored by the National Solid Haste Kanagiwsnt /Usoi. iat ion- Dtnlas,
Texas, December 9, 1976.
* J. Robert Holloway is an Environmental Engineer with the
Technology 5 Markets Branch, Resource Recovery Division, U.S.
Environmental Protection Agency.
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Four key points can be made regarding markets for RDF as a
supplemental fuel:
1) Electric utilities dcmn'nate market potential: In
examining the markets for RDF, one fact which clearly stands
out is the importance of the electric utility industry.
Without use by this industry with its abundance of large,
coal fired boilers, it is questionable that solid refuse-
derived fuel can be marketed on a broad scale. Industrial
boilers have significant potential as a market. However,
though large in number, most industrial boilers are not
large enough in size to accomodate the RDF which would be
produced from plants of 500 tons-per-day or greater scale.
Marketing to multiple users could partially solve this
problem, but introduces other problems of its own. Thus,
electric utilities deserve a special examination.
2) Technical uncertainties reduce user interest. In
a demonstration project, RDF has been burned successfully in
a coal-fired suspension boiler. However, experience is
extremely limited and technological uncertainties remain.
A principle concern is the possibility of increased air
emissions. Also, some aspects of boiler performance, such
as corrosion and ash handling, are not yet satisfactorily
resolved. Many utilities, though cautious toward these
technical issues, do net see them as major, insurmountable
barriers. However, costs may be experienced in addressing
them which would have to be considered in determining a
price for the RDF. Furthermore, many utilities are waiting
for satisfactory resolution of these technical issues
before signing agreements or contracts to purchase RDF.
3) RDF use may not be advantageous to electric utilities.
Utilities have shown a significant interest in possible purchase
of waste-derived fuels, prompted largely by a desire to be
socially responsive. However, the electric utilities have a
unique set of institutional constraints which question the
rationale of their involve.vent in purchasing and burning a
waste-derived fuel. Particularly significant is the fact that
profits of electric utilities are regulated. Since fuel savings
must generally be passed through to customers, there are not
strong profit incentives for using waste-based fuels. In
addition, the primary objective of electric utilities is to
provide reliable service. New, unproven fuels are inconsistent
with that objective. In view of these institutional factors,
even small technical uncertainties take on added significance.
In short, why take any chances?
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4) Costs Incurred in usjnn RDF can reduce its value
significantly. Some of the major costs involved in "using RDF
can include (1) receiving, storage and firing, (2) modifications
required (if any) for air emissions control, ash handling, or
additional boiler maintenance, (3) economic dispatch penalty,
i.e., the increase in electric generating cost which might
result from operating boilers equipped to fire RDF instead of
operating more efficient boilers.
The magnitude of these costs will vary from case-to-case.
There is not yet sufficient experience to reasonably estimate
some of them. However, those which can be estimated, such as
storage and firing costs, are clearly not minor. These costs
could range from $2.00 to $6.00 per ton of RDF even if the
RDF processing plant is located adjacent to the power plant
and transportation costs are eliminated. Transportation
could add $3.00 to $4.00 of additional cost. By comparison,
RDF might have a gross value (based on heat content alone) on
the order of $7.00 to $16.00 per ton. Thus, when estimating
costs for RDF supplemental fuel systems, it is important to
estimate the net price which can be obtained for the RDF by
taking into account these costs.
The above points by no means suggest that electric utilities
are not a viable market, or that RDF sold to them would have little
or no value. It merely points out that electric utilities do not
yet represent an established market for RDF and that until there is
more experience, the extent of their interest in RDF or the net price
which they will be able to pay are still uncertain. In the neantime,
it is appropriate for communities to continue to work with utilities
to determine if satisfactory RDF purchase conditions can be negotiated.
Background
What is refuse-derived fuel?
The term refuse-derived fuel can refer to any usable fuel produced
by mechanically, thermally, chemically, or biologically processing raiv
solid waste. For example, a gas or oil product resulting from pyrolysis
of solid waste could be a refuse-derived fuel. A refuse-derived fuel
may be used either as a supplement to fossil fuels in existing steam
generators, or as the sole fuel in a new steam generator designed
specifically for waste burning. However, in its common usage, refuse-
derived fuel (RDF) has come to represent a sol id product produced by
mechanically processing municipal solid waste for use as a supplement
to fossil fuels in existing steam boilers. This latter concept is the
subject of this paper, and the term "RDF" used here refers to solid
RDF.
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RDF can be produced in three physical forms: "fluff," "dust,"
and "densified."
• Fluff RDF can be produced by either wet or dry processing.
Using dry processing, waste is shredded, usually to 1 to
1 1/2 inch particle size, and then separated in an air
classifier into a light fuel fraction (RDF) and a heavy
fraction of primarily non-combustibles. Using wet
processing, waste is pulped in a device called a hydro-
pulper, the resulting slurry is passed through a cyclone
to remove the heavy primarily non-combustible portion, and
the remaining organics are dried. Additional screening or
other product upgrading steps are often used in either
process.
• Dust RDF can be prepared by adding an embrittling chemical
to shredded waste and pulverizing it into a powdery material.
Currently, dust RDF has been prepared by only one company,
which has developed a proprietary process.
• Densified RDF is fluff or dust RDF which has been densified
into pellets or briquettes.
Current Experience
There is only limited experience in producing any of these RDF
forms or burning them as supplemental fuels. Fluff RDF preparation
and burning has been demonstrated at an EPA supported project in
St. Louis, Missouri, and implemented commercially at Ames, Iowa. A
demonstration facility, partially supported by the Maryland Departme-it
of Environmental Service, is operating in Baltimore County, Maryland.
The St. Louis demonstration facility has operated intermittently
since 1972. The 45 ton-per-day facility used single stage shredding
and vertical chute air classification to recover about 80 percent of
the waste as 1 1/2 inch fluff RDF. The RDF was trucked from the City
operated processing plant to Union Electric Company's Meramac Power
Station where it was pnuematically fired into a 125 megawatt pulverized
coal-fired steam generator at heat input rates up to 27 percent. Thu
experimental facility is no longer operating.
The Ames, Iowa project has been operating commercially since
November 1975. The plant effectively handles the 150 tons of waste
generated daily by the City. The 40 ton-per-hour facility uses two
stage shredding, followed by vertical chute air classification to
recover about 80 percent of the waste as 1 1/2 inch fluff RDF. The
RDF is pnuematically transported to the adjacent City Powsr Pl.-.n!
where it can be fired into a 33 megawatt pulverized coal fired boiler,
and two small spreader stoker boilers.
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The Baltimore County, Maryland facility has been operating since?
January 1976. The plant is currently utilized to shred and landfill
solid waste and recover ferrous metals. Test programs to burn a shredded
and air classified waste are simultaneously being carried out. Tests
have taken place or are planned to burn the RDF in a spreader stoker
boiler and cement kiln. Tests in a suspension-fired boiler may be run
in the future. The facility has a capacity of 120 tons-per-hour and
currently handles about 700 tons-per-day of solid waste. It uses two
single stage shredding lines to reduce waste to 1 to 2 inch particle
size. This is followed by two-stage verticle chute air classification:
Other cities which have recently completed construction of a
facility to produce fluff RDF are Milwaukee, Wisconsin, Chicago,
Illinois. In both cases, the fluff RDF is to be utilized in suspension
fired electric utility boilers.
Experience with both dust and densified RDF is significantly
more limited. A privately-owned dust RDF pilot plant has operated,
and a larger facility in E. Bridgewater, Massachusetts is in shakedown.
A commercial facility is under construction in Bridgeport, Connecticut.
The same proprietary process is involved in all three projects.
Densified RDF has been produced and burned only on a test
basis to date. EPA's Office of Research and Development is currently
conducting tests of preparing and burning densified RDF at large
scale in'Washington, D. C.
Thus, there is an interesting dichotomy of limited experience,
yet a willingness to proceed. In addition to the cities mentioned
above, at least nine other cities are currently involved in design
of an RDF system. Numerous other cities have commissioned feasibility
studies. This activity suggests a widespread belief that RDF can be
successfully produced. There is a sobering question of markets which
these cities must face, however. Few if any cities to date have been
able to obtain firm, long-term contracts for RDF with well defined
product revenues. Some of the possible reasons for this market
uncertainty are discussed in this paper.
Markets for RDF
Electric utilities and industrial plants are two basic potential
markets for RDF.
Most large electric utilities use primarily "suspension fired"
boilers where the fuels are pnuematically fired into the boiler and
burn in suspension. Most industrial boilers are relatively small
"spreader stoker" fed units that burn part or all of the fuel on a
moving grate in the furnace. Fluff or dust RDF can be used in
suspension boilers. Fluff and densified RDF can be used in the grate
equipped boilers.
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Table 1 contains a summary of the capacity of these two markets
nationally. Though large in numbers, industrial boilers have only
about one-third the total national capacity of electric utility
boilers. However, far more significant is the average boiler capacity
in the two sectors. Average electric utility boiler capacity is
630 million Btu/hr., while average industrial boiler capacity is only
30 million Btu/hr.
To accommodate waste from large urban areas, large boiler
capacities are necessary. For example, a city that generated 500
tons-per-day of refuse would require boiler capacity of at least
500 million Btu/hr to consume the RDF produced.* Most electric
utility boilers are above this size. However, only about 55 coal
fired industrial boilers are larger than 500 million Btu per hour.
These boilers are concentrated primarily in the east-north central
area of the United States.
This does not mean that industrial boilers are not an important
potential market. Many individual industrial plants have multiple
boilers. This would expand the capacity in any one location. Also,
several industries in a given area may have boilers. This means that
marketing of RDF to multiple users in a given area is a distinct
possibility. Nevertheless, from a capacity standpoint, electric
utility boilers offer a significantly greater potential than industrial
boilers.
Another factor is the stability of the user. Electric utilities
offer a more stable long-term market because they are unlikely to
cease operations. The same cannot be said for industrial plants. Even
very large companies can suspend or cease operation of individual plants.
On the other hand, the gross value of the RDF is likely to be lower
when used in an electric utility boiler vs. an industrial boiler. This
is because large electric utilities have long-term, high volume fuel
purchase contracts that result in lower fuel costs than for most industries.
Because a user would buy RDF based on its fuel cost savings, gross revenues
could be lower when marketing RDF to electric utilities.
But, all factors considered, the electric utility boiler market
appears to have nuch more potential than the industrial boiler market.
This assumes that 350 tons of RDF are produced from the 500 tons
of waste, that 40 percent of the boiler heat input is provided
by the RDF, that the boiler averages a 70 percent load factor
(capacity utilization), and operates 24 hours per day. Using, RDF
to provide 40 percent of total boiler heat input is considered to
be possible in "stoker" boilers. For "suspension" boilers, 20
percent or less is a more likely estimate.
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Key Factors that influence marketability of RDF, particularly to
the electric utility market are discussed below. Included are:
• Technical Factors
1) Fuel characteristics of RDF
2) -Boiler corrosion
3) Boiler residue
4) Boiler emissions
• Institutional Factors Affecting Electric Utilities
• Economic Factors: Determinants of RDF Value
Technical Issues in Marketing RDF
Characteristics as a fuel. Table 2 shows a comparison of certain
key characteristics of RDF and coal from the St. Louis and Ames, Iowa
projects previously described. One would expect the characteristics
of the St. Louis and Ames RDF's to be similar since in both cases
approximately 80 percent of air classifier inputs have been recovered
as light fraction (RDF). However, the data show some interesting
variations. One explanation for the differences may be that the
St. Louis data are the average of all measurements made over the life
of the project. The Ames data represent a four month average, and thus
reflect seasonal influence.
In both cases, the data show the heat content of the RDF's to be
about half that of coal, while both ash and moisture are significantly
higher. Sulfur, on the other hand, is lower in RDF than coal. The
lower sulfur content has been viewed as a potential benefit from an air
emissions (SOv) standpoint. However, the higher concentrations of ash
may create asn handling problems, and the higher concentrations of
moisture decrease the effective heat value of the RDF.
These RDF characteristics are not representative of what can be
achieved by additional processing of waste to produce RDF. For example,
additional processing such as screening and drying can reduce both ash
and moisture content. Processing into a dust RDF will produce a
significantly higher heat content, as well as lower ash and moisture.
There is a trade-off between the cost of the processing employed in
producing an RDF, and the value of the resulting product. Requirements
of the user will determine what specifications the RDF must meet.
Burning experience. There are three primary areas of interest
regarding boiler performance when burning RDF: corrosion, bottom ash,
and air emissions.
-115-
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Corrosion. Currently there are only limited data on boiler tube
corrosion, and all of it is based on short-term burning experience.
However, early indications are encouraging. Analysis of critical boiler
components at the Union Electric Company indicated no observable increase
over coal only firing. However, this was based on intermittent firing of
roughly 50,000 tons of RDF over three years, which in total constituted
less than 3 percent of total boiler heat input. Thus, these observations
cannot be considered the last word. Nevertheless, the willingness of
Union Electric to move ahead with a $70 million project to burn 6000
tons of refuse daily is strong testimony to their belief that corrosion
would not be a significant problem. Discussions which EPA has held with
other electric utility representatives indicate that corrosion is not
generally perceived as a prohibitive problem area. Even still, some
utilities prefer to take a wait-and-see posture until there has been
more operating experience.
Bottom ash. The bulk of existing data on bottom ash are from
testing at St. Louis. At 10 percent RDF heat input, bottom ash
increased 4 to 7 times over that for coal only firing. This was
due both to the fact that RDF has 5 to 6 times as much ash as coal
on an equivalent heat value basis, and the fact that not all of
the RDF fired into the furnace actually burned. About 10 percent of
RDF heat content was lost to bottom ash vs. less than 1 percent for coal.
There is some experience with suspension firing of RDF at Ames, Iowa,
although most of Ames' experience to date has been with burning in a
spreader stoker boiler. Early observations of bottom ash during suspension
boiler firing generally confirm the St. Louis results. Though specific
data are not available, it can be said that substantial quantities of
RDF did not burn in suspension and added to the bottom ash loading.
Increased bottom ash implies that alterations in boiler ash handling
may be required. One notable impact at St. Louis was that ash pond BOD
and COD increased with RDF firing to the point where additional treatment
would have been required. This treatment can be easily accomplished from
a technical standpoint, but naturally involves a cost that would ultimately
be charged against the RDF.
However, bottom ash can be reduced by increasing burn-out of the
RDF in the boiler. Modifications in method of firing into the boiler --
that is, raising the elevation of RDF firing nozzles to increase retention
time of RDF particles in the boiler -- could possibly increase burnout.
At Ames, Iowa, a unique method of increasing burnout in the suspension
fired boiler is being tried. Combustion air is being injected into the
boiler just above the water line in the bottom ash pit to allow the
unburned RDF particles to burn as they float on the surface of the
water. The effectiveness of this approach has not been fully evaluate1';
due to limited operating experience with the suspension fired boiler.
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Another possible means of increasing burnout and reducing bottom
ash is to recover a higher quality RDF fraction, that is, one with a
lower inorganic content and smaller, less dense particles. This may
be possible by recovering a lower fraction of air classifier inputs
as light fraction, say 60 or 70 percent, rather than 80. Shredding
to a smaller particle size is also an alternative to increase burnout.
Furthermore, the RDF could be screened or dried. However, these
actions would result in either higher net processing costs or lower
product yield.
Air emissions. At St. Louis, data were collected on a wide range
of emissions when firing both coal only and combinations of coal and
RDF. Measured were particulates, SOX, N0x> and trace elements. A more
complete discussion of these results is available in another EPA report.^
The data did not confirm any increase or decrease in either SOX or
NOX emissions when firing RDF with coal vs. coal-only firing. A
decrease in SOX had been expected because RDF has a lower sulfur content
than coal. Apparently at firing rates of 5 to 20 percent, the impact
on SOX emissions was not great enough to be reflected beyond the scatter
of data.
Trace elements were measured even though there are no Federal
standards for any of these elements for coal fired steam generators.
Emissions were found to increase for most of these elements when
firing RDF. For three of the elements measured (lead, berryllium,
and mercury), EPA has determined acceptable ambient air levels.
Ambient air levels of these elements, estimated from measured stack
emissions at St. Louis, were well below these levels when firing
both coal-only and coal and RDF.
Particulate emissions were viewed as one of the key issues in
RDF firing. At St. Louis, there was no measured increase in controlled
particulate emissions up to the boiler design load of 125 megawatts
when firing coal and RDF vs. coal only. However, above boiler design
load, that is, between 125 and 140 megawatts, the actual maximum boiler
load, controlled emissions did increase substantially when RDF was
fired with coal.
Measurements of uncontrolled emissions indicated no significant
change with coal plus RDF firing vs. coal only firing at any boiler
load. Thus, a decrease in electrostatic precipitator (ESP) efficiency
was the apparent cause of the increases measured in the controlled
stack emissions. A number of possible changes brought about by burning
RDF which could have caused the efficiency decrease were investigated.
Although no totally satisfactory answer was found, an increase in gas
flow rate through the ESP was identified as the primary cause' of the
loss in efficiency. The increased flow rate resulted fron the hujlif-
moisture content of the RDF compared with coal.
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The St. Louis emissions results should be useful in determining
the feasibility of future RDF projects. However, caution should be
exercised in drawing generalized conclusions from these results.
Emissions in other situations will depend on a number of
site-specific factors including boiler and ESP design, type of RDF,
and type of coal. It is important that these factors be examined
prior to decisions to proceed with an RDF project.
It is possible that particulate emissions, even if they do increase,
can be reduced by changes in RDF firing procedures, ESP operation, or
other factors. If such actions are unsuccessful, mechanical modification
to the ESP would probably be an effective, although potentially costly,
solution. As is the case with the other technical factors discussed,
there is a feeling that air emissions, while possibly requiring corrective
action in some cases, can be properly controlled. The question is what
impact will any necessary adjustments ultimately have on the net value
of the RDF.
Institutional Issues in Utility Markets
Electric utilities have been the target of RDF marketing efforts
for a variety of reasons. They have large capacity for using RDF and
are located in virtually all urban areas where solid waste is generated.
They represent a stable market, since individual utilities can be
expected to be operating for the duration of long-term contracts.
From the utilities' perspective, purchase of RDF provides an
opportunity to assume a good-neighbor role in the community by providing
a valuable service. At the same time, a new, though limited, source of
fuel can be obtained. In some cases, there may be some opportunity for
a profit or lower rates to customers.
However, there are a number of problems with electric utilities
as RDF markets:
• The major objective of electric utilities is to provide
reliable service . Any technological uncertainties which
might be associated with RDF use are inconsistent with that
goal.
• Utilities, like many other instutitions, have limited
financial capability. Investments for RDF handling compete
with investments in new generating capacity.
• Utilities are a profit-regulated industry. This diminishes
the economic incentive to use a cheaper fuel such as RDF,
which carries with it increased operating risk. For example,
any savings in fuel costs would probably have to be passed
through to users in lower rates. This makes it difficult
to earn a rate of return commensurate with risks in using
RDF.
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• Utilities, like other industries, are under increasing pressure
to meet environmental regulations. Any possibility of
increased emissions from burning solid waste could make
utilities very cautious about its use.
Recently, the Edison Electric Institute (EEI) surveyed its member
utilities to determine their views on use of RDF as a fuel. Here are
some of the results:
• Forty nine electric utilities were actively studying the
use of municipal solid waste as a part of 62 MSW utilization
studies.
• Seventy six percent of these studies C47 of the 62) involve
purchasing waste-derived fuels, 15 percent involve purchasing
steam, and 3 percent involve electricity purchase.
• Of the 47 studies involving purchase of fuel, 29 involve
shredded solid waste; 4 involve incineration of raw solid
waste; 3 involve the use of pelletized RDF; 6 involve
pulverized (dust) RDF; and 5, the use of a pyrolysis fuel.
Wy would an electric utility want to become involved in such a
project? The four reasons most commonly cited in the survey were:
• to make a profit. Despite the regulatory constraints, there
may be opportunities, though limited, to increase profit by
such ventures. (However, most utilities do not think that
the potential for making a profit is very high.)
• to supplement available fuel resources. However, while
a new source of fuel would be expected to be a possible
benefit to electric utilities, solid waste has been viewed
by that industry as not available in sufficiently large,
reliable quantities to be a significant new fuel in general.
In specific circumstances, it could mean a great deal,
however.
• to ensure that a resource recovery project is compatible
with the needs of the utility. If a utility believes that
a project is going to be built in any case, they may get
involved early to ensure that their interests are
represented.
• to assist in solving a significant public problem.
Utilities tend to place a high value on efforts at civic
improvement. Since they are constantly under fire from
rate-payers, any actions to improve their community image
are looked upon favorably by management.
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Over half of the companies involved in studies indicated the last
reason, public service, to be their primary motivation. Only 14 percent
would insist that participation result in a profit to them.
However, the public service motive can go only so far. The industry
realizes that it has no real responsibility to dispose of solid waste.
Its primary responsibility is to provide reliable and adequate service at
the lowest reasonable cost. H. J. Young, Senior vice president of EEI,
testifying before the Congressional Symposium on Resource Conservation
and Recovery on April 7, 1976, stated the following: "In order for
utilities to consider becoming involved in resource recovery projects,
these systems must be developed in such a way that will ensure
reliability of service, be cost competitive with other fuels, minimize
capital investment risks, comply with environmental regulations, and
avoid large increases in operating costs."
It is questionable that operating experience to date is sufficient
to definitively address these factors. Thus, there seems to be a
tendency toward a "wait-and-see" attitude by many utilities. Utilities
which have become involved are requiring contracts which provide an
opportunity for them to discontinue their involvement at minimum cost
if significant problems develop during a test period. Also, utilities
have shown a reluctance to put up "front-end" capital, and naturally
expect to reduce the price paid for RDF to cover any incremental costs
experienced. This is by no means a criticism. It is simply good
business on the part of the utilities.
The widespread interest shown by utilities at this still early
stage of resource recovery implementation, when many technical questions
remain unanswered, is a strong, favorable indication for the future.
However, at the current time, there are still a number of significant
constraints facing this market.
RDF Value
The price that a user, particularly an electric utility, will pay
for RDF will depend on numerous factors. A starting point would be
a simple equation such as the following:
Prdf = Pcoal - Crdf
Expressing all factors on a per unit of heat basis, Prdf is price
received for the RDF, Pcoal is the price paid by the utility for coal,
and Crdf is the net incremental costs experienced by the utility as a
result of RDF use.
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Thus, if $1.00 per million Btu were paid for coal, if RDF had a
heat value of 10 million Btu/ton, and if a utility experienced incremental
costs totaling $5,00 per ton for each ton of RDF used, then:
Prdf = $1.00 per million Btu - $.50 per million Btu
= $.50 per million Btu ^
To use this equation accurately requires that the measurement of
heat value of the RDF be at the same moisture content as the coal being
used, and that any loss of RDF due to incomplete burnout be taken into
account. Otherwise, the usable heat of the RDF relative to coal would
be overstated.
Another way of looking at the pricing determination substitutes
the value of the coal saved (SAVcoal) for the price of coal per million
Btu.
Prdf = SAVcoal - Crdf
Using tins equation, if one half ton of coal at $14.00 per ton
were saved for each ton of RDF burned, and ••'f it cost $5.00 incrementally
for each ton of RDF burned then:
Prdf = $7.00 - 5.00
= $2.00 per ton (or $.20 per million Btu)
These are only examples, and the costs used are not intended to represent
an actual situation.
The latter formula assures that the user pays only for the usable
heat produced by the RDF. By measuring coal actually saved, it
automatically takes into consideration factors such as burnout of the
RDF, heat lost when vaporizing moisture in the RDF, and other changes
in boiler efficiency, such as increased stack heat loss. This approach
suffers from the practical problem that it may not be possible for a
utility to accurately measure the quantity of coal saved based on the
amount of electricity generated. This is because the unit's steam and
electricity generating efficiency changes: 1) as the boiler gets older,
2) between maintenance and cleaning cycles, and 3) with changes in
boiler loads.
In practice, both of the above equations can lead to the same result
in terms of RDF value if sufficient data are available to apply them
accurately. Both of these equations assume that the RDF is priced
equivalently with coal on a heat value basis (after deducting incremental
costs) rather than being priced at a discount. If a utility wanted to
discount the RDF price below that paid for equivalent Btu's from other
fuels (perhaps to provide an economic incentive) then this discount
would also be deducted in calculating the price of the RDF.
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The most complicated factor in the above equations is the incremental
cost incurred in using RDF. Some of the components of this cost are:
1) Capital and operating cost of RDF storage and firing
facilities.
2) Increased holler operating or maintenance costs due
to corrosion, ash handling, air emissions, or other
factors.
3) Economic dispatch penalty, i.e., the increase in
overall electric generating cost to the electric
company, which might result from operating boilers
equipped to fire RDF instead of operating more
efficient units, such as nuclear or hydro powered.
4) Cost of replacement electricity while unit is out of
service for initial modification to fire RDF.
There are also other, possibily less significant, costs which can
arise in specific situations.
It is difficult to define in the abstract what value should be
placed on any of the factors in this equation, and they will naturally
vary from case-to-case. However, it is worth pointing out the order of
magnitude of some of the key components of the cost factor (Crdf) in
comparison to the gross value of the RDF.
One item is the capital cost of receiving, storage, and handling
facilities for RDF at a power plant. Definitive examples of these costs
are limited at the present time. But a consideration of available
information suggests that we might assume $4 to $8 million as a rough
ballpark estimate of the capital investment to handle 1000 tons of RDF
per day at a power plant. Amortizing $4 million over 15 years at
6 percent translates to $1.10 per ton of RDF. Amortizing $8 million
at 12 -percent over 10 years amounts to $3.90 per ton of RDF. (if the
storage and handling facilities were owned and financed by a munici-
pality or authority, 6 percent financing and 15 to 20 year amortization
might be expected. If the same facilities were owned and financed by
the utility or a private firm, 12 percent and 10 years is more likely.)
Operating costs (labor, utilities and maintenance) at the power
plant can also be crudely estimated. Two feasibility studies
(conducted for the Tennessee Valley Authority and the Delmarva Power
and Light Company, Delaware) estimated costs in the range of $0.75 to
$1.20 per ton of RDF. Another estimate, obtained from private sources,
placed O&M costs at around $2.50 per ton of RDF. Thus, collectively,
capital and operating costs amount to on the order of $2.00 to $6.00 per
ton of RDF. If the RDF processing plant is not adjacent to the power
plant where the RDF is to be burned, then truck or rail transport will
be required. One cost estimate for a project now under construction was
S3.00 to S4.00 per ton of RDF for an 8 mile track transport. Thus, the
cost of handling RDF can oe significant.
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Other components of the utility RDF cost factor, such as possible
costs of emissions or residuals control and economic dispatch penalty,
would have to also be subtracted from the gross value. No reasonable
estimates can be made of these costs at this time. In specific instances,
they could have values ranging from zero to several dollars per ton.
These costs must be subtracted from the gross RDF value to obtain
a net price. -As a basis for estimating possible gross RDF values,
Table 3 shows the average contract price paid for coal in various
regions of the United States in June 1976. Based on these data, it
appears that RDF might have a gross value of roughly $0.65 to $1.25
per million Btu.
Table 4 combines these ranges of costs and revenues to determine a
possible range of net RDF values. The result is net values ranging from
a high of over $13.00 per ton to a low of a negative value of nearly
$4.00 per ton. Not included in this estimate are any costs relating to
pollution control or other additional boiler maintenance costs, or an
economic dispatch penalty. There could be no costs for these items, or
in some cases significant costs could be experienced.
There are two purposes in pointing out this range of potential
values. One is fo illustrate the need for municipalities to thoroughly
analyze their own situation, rather than depending on suppositions or
approximations of RDF value. The other is to point out the significance
of the difference between net and gross RDF value. However, the net RDF
value is only one component of an overall economic analysis of a plant
to prepare RDF and sell it as a fuel. Capital and operating costs of
the RDF processing plant and revenues from recovery of any other products
must be estimated. Then, this overall system net cost must be compared
with costs of alternative disposal and recovery options.
Conclusions
Obviously, markets are a key factor in the viability of any
resource recovery technology. However, they take on added significance
in the case of a refuse-derived solid fuel (RDF). Some other technologies
produce "final" end products, such as steam or electricity, which are
not significantly different from the same products produced by other
means. Still others produce intermediate products (fuels), such as oil
or gas, representing chemically refined solid waste. However, refuse-
derived solid fuel (with one notable exception) is physically processed
solid waste - essentially size reduced and classified by density. A
key aspect of the technical and economic appeal of this technology is
its simplicity; there is no chemical processing equipment or thermal
conversion equipment employed in producing a solid RDF. However,
obviously the product is somewhat more crude than final products such
as steam or more refined waste-derived fuels. Thus, the front-end
processing simplicity may simply translate into a more difficult
marketing task.
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TABLE 4
RANGE OF NET RDF VALUES
Revenues
Gross RDF Value
RDF Storage and Handling Costs
Capital Costs
Operating Costs
Transport Costs
Net RDF Value per Ton
Other Costs
Low
$6.501
Low
$3.903
2.50
4.00
(-$3.90)
High
$16. 252
High
$1.104
.75
0
$13.40
Economic Dispath ? -0-
Pollution Control ? -0-
Other ? -0-
Based on 10 million Btu/ton; 65<£ per million Btu
^ Based on 13 million Btu/ton; $1.25 per million Btu
^ Based on $8 million amortized over 10 years at 12 percent
* Based on $4 million amortized over 15 years at 6 percent
Source: U.S. EPA estimates.
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However, there is a tremendous momentum behind this technology.
A host of firms are marketing RDF processing plants, many cities are
considering implementation of such a system, and many electric utilities
are considering involvement as a fuel user.
The primary message which should come from a consideration of
both the market uncertainties and the great enthusiam behind this
recovery approach should be one of realism. One should not conclude
that technical or economic problems will prevent implementation of
this technology, nor that all the problems will simply work them-
selves out. Important marketing questions exist at the present
time and should be understood by those considering such a system.
But the technology is still in an early stage of development. It
is important that industry and government understand both the problems
and the opportunities and work together to resolve the uncertainties
and build a foundation for future implementations.
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References
1. Holloway, J.R., EPA Resource Recovery Demonstration: Summary
of Air Emissions Analysis, Haste Age. August 1976, p. 50-52.
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THE ENERGY PURCHASERS' STANDPOINT
PITFALLS IN PLANNING
AT den H. Howard
President - Energy Systems Division
Wheelabrator-Frye, Inc.
At the present time, a 1200 TPD solid waste steam gen-
erating plant is in operation in Saugus, Massachusetts. The
steam output from this plant is piped across the nearby Saugus
River to a large industrial plant for use in processing, testing
and power generation. The 2 billion pounds (907,100 t) annually
to be supplied will reduce the fuel oil requirements of the
industrial plant by about 73,000 gallons (276,335 litres) of #6
fuel oil daily.
This paper, while describing the basic features of the
plant, will deal primarily with the inception of the idea, the
attempts at municipal participation, funding, securing of permits
and some of the unusual features of operation due to its integra-
tion with the industrial plant's steam system.
The General Electric Company operates its River Works
Plant in Lynn, Massachusetts, bordering on the Saugus River. This
large industrial complex occupies 278 acres and employs about
13,000 people. Its energy systems are complex and its steam plant
capacity is over 1 million pounds per hour (453.5 t/hr) and its
power generating capacity is 80 MW. This consists of 60 MW of
steam turbine capacity and 20 MW of gas turbine capacity which is
part of a combined cycle package of a gas turbine and a heat
recovery steam generator.
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Steam is used for building heating, processing, and for
power generation, but the largest demands on the steam system
are from testing operations. The plant manufactures steam tur-
bines and jet engines and large flows of up to 450,000#/hr (204.1
t/hr) are required to meet the conditions of an individual test.
Steam ejectors are used for altitude simulation in jet engine
testing, and some ejectors can pull in access of 250,000#/hr
(113.4 t/hr).
Steam is generated at 2 pressures: 650 and 200 PSIG
(4481.8 and 1379.0 kPa). The bulk of the steam is generated at
650 PSIG (4481.8 kPa) and is used directly by some test equip-
ment at that pressure. The rest goes to extraction turbines
which make up the bulk of the supply to the 200 PSIG (1379.0 kPa)
system. The steam plant consists of 7 boilers, the largest of
which is 300,000#/hr (136 t/hr), 650 PSIG (4481.8 kPa) dual-
fired, oil or gas unit.
In the late 60's, plans were being made for the normal
replacement of two units which were reaching the end of their
useful life. At the same time, the City of Lynn was coming to
the realization that they would be facing a solid waste crisis,
within a few years, and as General Electric was the major tax-
payer in the community, they would share in any increased cost
resulting from the solution of the problem.
It was really at that time the thought of a joint solu-
tion became apparent. Why not think of solid waste as an asset,
rather than a liability, and examine the possibility of reqover-
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ing the heat content as fuel? Many years previously, the indus-
trial plant had two small steam generators which were fired by
rubbish, but could a unit be built today large enough to replace
the two oil-fired units soon to be retired?
City officials were approached to see if they would be
interested in providing some form of collection facility on land
owned by the company across the Saugus River from the plant. It
was originally contemplated that the rubbish would be shredded,
then conveyed across the river on an enclosed conveyor, and the
residue returned the same way.
It was immediately apparent that if steam were to be
generated at the plant's system conditions of 650 PSIG (4481.8
kPa), 825°F (440.5°C), and in quantities between 350,000 to
400.000t/hr (158.7 - 181.4 t/hr), we were dealing in some un-
knowns. The concern for corrosion in the superheaters and
the overall effect of chlorides on boiler surfaces was upper-
most. It was felt a feasibility study was necessary to determine
if the concept was both technically and economically sound.
Working with the City officials and a major boiler manu-
facturer, funding was received through H.E."W. and the Office of
Solid Waste for the study. The project examined the communities'
solid waste quantities and makeup, its chemical content and heat-
ing value. The boiler manufacturer examined preliminary design
concepts and paid particular attention to corrosion considerations.
Concurrently, the study looked at the size of units and the
reliability requirements and how steam from an external source
could best be integrated into the plant's steam system.
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The study indicated, as you would expect, that solid waste
could be considered an acceptable low-grade fuel and facilities could
be designed to recover the heat value from it. The economics looked
particularly attractive, although it should be pointed out these
studies preceded any real concern for environmental control requirements
which have added significantly to the capital costs of the installation.
The study looked at various combinations of equipment and locations.
You will recall the collection site was across the river from the
industrial plant, and either the steam or the rubbish and residue
would have to be transported across the water. The study also evaluat-
ed the economics of the entire installation on the plant side and, of
course, showed the lowest cost per ton; but, the Company did not have
the available land, nor could they stand the traffic congestion of
40 or 50 rubbish trucks a day in the plant, so that was not considered
a viable combination.
I mentioned earlier that one plan was collection and shredding
on the Saugus side of the river and conveying the rubbish over to
a boiler on the Lynn side and returning the residue, utilizing the
same conveyor. Another was the entire collection, burning and steam
generation, on the Saugus side and transporting the steam across the
river on a pipe trestle to the Lynn side. A variation of both of
these was the generation of saturated steam on the Saugus side and
a separately fired superheater across the river at the plant site.
It was felt this might avoid some of the contemplated problems of
corrosion which might only be present at the higher temperatures.
After careful consideration of all the technical problems, space
requirements, and capital cost, the system chosen has the entire
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rubbish burning steam generating facility on one side of the river
and the steam transported over a pipe trestle at the pressure and
temperature of the Plant's steam system.
Upon completion of the feasibility study, the actual sizing
and costing of the plant was necessary in order to approach the
proper municipal authorities for approval of a bond issue. It was
evident that the City of Lynn did not generate enough solid waste
themselves to produce the quantities of steam required. It had been
estimated that in order to meet the steam demands of 225-250,000#/hr
(1020-113.4 t/hr) average and peaks of 350,000#/hr (158.7 t/hr),
a minimum size plant of 1000 TPD would be required.
Lynn's solid waste load was estimated in the vicinity of 350
TPD, so other communities were solicited and the North Shore Solid
Waste Disposal District was formed, with eight communities, under
provisions of the General Laws of Massachusetts. The district put
together a specification for the proposed plant and solicited proposals
from firms we felt had the technical resources to design, construct
and operate such a facility.
Throughout this process, which was time-consuming, the industrial
plant was facing a deadline due to the replacement schedule of its
boilers. Replacement steam was required by the later part of 1975
which meant preliminary design, funding and approvals had to be firmed
up in 1972.
Many evening meetings of the North Shore Solid Waste Disposal
District were spent listening to firms present their proposals.
Throughout this process, the industrial plant was cast in a unique
role. As a corporate citizen of one community, they had a vital
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interest in the proceedings, but had no justification to dictate or
rule on the capabilities of the proposers. But as the sole steam user,
(and without that steam sale, there would be no justification of such
a project) they had a vital concern first to have the assurance the
plant would be built, and secondly, that it could succeed. For the
first time, they were putting their destiny in the hands of others,
and they needed absolute confidence that their steam demands would be
met in a timely and economical fashion. If the plan faltered, they
had to make plans immediately to install conventional boiler equipment
to meet their 1975 replacement schedule.
Initial cost projections indicated a capital expenditure of
about 22 million dollars would be required to construct a 1200 TPD
plant, and municipal bonds were felt to be the most attractive way
of providing that capital. A problem developed in that the solid
waste district was made up of both cities and towns, and the town
meeting form of government was employed by some. Bond issues had
to be approved by town meeting and by city councils or boards of
aldermen, depending on the particular charter. It soon became
evident that it would be practically impossible to go into a town
meeting and ask for that town's share of a 22 million dollar bond
issue for a project so radical at that time. In this age of protest
and self-styled public-interest experts, long delays could be expe'Cted
if the necessary capital had to be raised in this manner.
While it was recognized municipal bonds offered the most at-
tractive interest rate, the possibility of industrial bonds at a
slightly higher percentage looked attractive. Their use required
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some legislative changes so that solid waste facilities would qualify
along with regular industrial construction. The necessary legislation
was obtained and bonding companies contacted, but here again the spector
of long-drawn out battles at town meetings loomed again. The bond
merchants explained that in order to sell industrial revenue bonds,
there must be proof of the ability of the venture to succeed and
that took the form of long-term or 20-year rubbish contracts. An
investor in a 20-year bond must have the assurance the plant could
meet its commitment of its steam sale and, therefore, must be assured
of a continuing supply of low cost fuel; namely, solid waste. While
the possibility existed that contracts could, in time, be negotiated
and approved by the proper authorities, the commitment date to the
industrial plant did not allow this.
When it appeared the entire project would falter because of this,
it became evident to some that private capital offered the only hope
to initiate the project. The cities and towns who made up the solid
waste district were presently, with one exception, dumping in a large
commercial landfill immediately adjacent to the plant's land in
Saugus, where the solid waste facility was to be built. This landfill
was receiving the rubbish for some 18 communities in the Greater
Boston-North Shore area. The State and local community had tried to
close this facility on many occasions, but there was no acceptable
alternative, so it was still operating. The owner approached the
company and suggested he would like to build the plant, realizing
incineration and energy recovery offered a long-range solution
with many benefits over operation of a sanitary landfill operation
in a hostile environment.
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They felt he needed a partner, preferably a company that could
bring in the technical resources to assure the plant's success as
this concept had never been done in this country. He was put in
touch with a major pollution-control manufacturer and engineering
firm, who had an association with a Swiss company that had built
over 50 rubbish-burning steam generation plants in Europe and Japan,
and more recently, one in Montreal, Canada. A joint ventuer was
formed, called REFUSE ENERGY SYSTEMS COMPANY(RESCO), and the planb
was originally financed by the two partners, and then refinanced with
industrial bonds once construction was underway.
A great deal of time went into the negotiation of the contract
between the industrial plant and RESCO. A high degree of redundancy
was required to assure the company their steam demands could be met
at all times, regardless of planned or unplanned boiler outage,
or even a prolonged rubbish strike. They have contracted for 2 billion
pounds/year (907,100 t/hr) of 650 PSI 825°F (4481.75 kPa 440.5°C)
steam which is generated-in 2- 750 TPD solid waste furnaces, each
capable of 185,000#/hr (83.9 t/h4) on rubbish or on oil firing.
The maximum demand will be 350,000#/hr (158.7 t/hr}, and this rate of
taking is allowed for 1200 hrs/yr. The average demand from RESCO
will be about 225-250,000#/hr (102.0-113.4 t/hr). The contract
requires a minimum flow of 65,000#/hr (29.5 t/hr) in order to keep
the 3,000 ft (914.4 meter) line at temperature.
The cost of steam purchased bears a direct ratio to the cost
if they were to generate it in their own plant. A formula was
conceived that uses a maintenance factor, depreciation, labor, etc.,
over the contract period of 14 years, plus factoring in the cost of
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oil and this equals the cost per 10001 the plant would have incurred
if they were forced to put in conventional fossil fired boilers.
A fixed percentage of that number determines the final cost/1000#
for the contracted steam. The main variable there is the price of
oil, so over the length of the contract the purchased price will be
affected by any fluctuation in the price of energy.
One of the more interesting features of the contract is the
total energy exchange between the two plants. The industrial plant
will supply to RESCO, a portion of their condensate, fuel oil and
all of their electrical needs on a total energy exchange basis.
They have excess turbine generator capacity, and will take RESCO's
steam over and above their contracted requirements and convert to
kilowatts for them. This will be done on a BTU/KW rate agreed to in
the contract. Condensate returned from the plant system and not
needed in their own boilers will also be sent to RESCO for a negotiated
rate which will cover heat content and pumping costs. Because the
plant had large #6 fuel oil storage facilities and were effectively
increasing that by the reduced usage in lieu of steam being generated
from solid waste, it seemed logical to eliminate the capital cost of
providing large fuel oil storage tanks, at the RESCO site. Oil is
supplied over the pipe trestle from the plant and is pumped to a
20,000 gal. (75,700 litres) day tank at the RESCO site which provides
easy suction for fuel pumps.
It is apparent that the plant running at full capacity burning
1200 TPD of rubbish can generate more steam than is required under
the present contract. The existing commercial landfill site could
accommodate a future industrial complex which could utilize the steam,
and the industrial plant is continuing studies as to the feasibility
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of increasing steam demands if they were to retire more of their
existing boiler equipment. The utility company shows interest in
excess power that can be generated and fed to their system.
The design of the solid waste steam generating facility follows
closely that of many successful European installations, some of
which have been in operation over 20 years.
Trucks will dump mixed refuse into a storage pit of 6700 tons
capacity, which is 5.6 days of storage at an average disposal rate
of 1200 tons/day (1091 t/day). This large storage capacity will
allow the plant capacity to be doubled without the necessity of increas-
ing the pit size.
Refuse will be transferred to the boilers or fragmenter by one
of two overhead cranes. One crane will be in continuous use and
the other will be a standby.
The facility has two refuse boilers, each will consume an average
of 600 tons/day (546 t/day) of refuse and will produce approximately
180,000 Ib/hr (68 t/hr) each of 690 PSIG (4758 kPa) and 875°F (468°C).
The refuse boiler units are designed with a three level, inclined
reciprocating grate, water wall furnace and a convection heat transfer
surface containing a three section superheater, generating section and
economizer. Gases leaving each boiler enter an electrostatic pre-
cipitator and are then conveyed by the ID fan to the concrete stack.
Backup steaming capacity is provided by fuel oil burners located
in each refuse boiler and two 120,000 Ib/hr (54.5 t/hr) package boilers
designed to burn fuel oil. The backup steaming capacity will not be
used under normal circumstances, but is installed to make sure that
the industrial plant's steam requirements will always be met.
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Each refuse boiler is equipped with an electrostatic precipitator
for removal of particulate from the flue gases. Each boiler will
discharge a maximum of 200,000 ACFM (5660 M3/Min) at 430°F (221°C)
which is equivalent to 107,000 scfd (3028 M ). Particulate emissions
from the boiler are about 1-2 grains per scfd (35-70 g/M ) adjusted
to 12% CO.,. The precipitator is designed for an efficiency of 97.5%
to maintain emissions to the atmosphere within the allowable of .05
grains per scfd (1.77 g/M ).
Oxides of nitrogen are produced by burning a high nitrogen
content fuel with a high efficiency burner that produces flame
temperatures about 2800°F (1538°C). Refuse is a low nitrogen and
relatively low heat content fuel. The composition of refuse, as fed
into the burning zone, and the method of handling the fuel during
combustion precludes the generation of high heat zones and high
flame temperatures associated with the burning of highly pulverized
coal of highly atomized oil in conventional utility type power boilers
and therefore eliminates the possibility of generating nitrous oxides.
Refuse is a low sulphur fuel with a sulphur content of less
than .3% and usually less than .1%. Fuel oil burned in the plant
will be sufficiently low in sulphur content to meet the requirements
of the Massachusetts Bureau of Air Quality Control requirements.
The refuse storage pit is located in the refuse handling
building which is totally enclosed. The intake for the forced draft
fans, which provide combustion air to the refuse boilers, is from
this building. This arrangement provides for a slight negative
pressure in the building and thereby prevents any odors escaping
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to the surrounding area. The odors are conveyed by the combustion
air to the furnaces where the temperature is sufficiently high to
completely destroy them.
Hydrocarbons are formed in the furnace, however, the operating
temperature of the furnace is too high and the residence time too
long to allow them to escape without being burned. The temperature
would have to be below 1000°F (538°C) in order for hydrocarbons
such as methane, parafins, olefins, etc., to escape without going
through the combustion process and producing CO2 and water which are
harmless.
I commented previously on the difficulties encountered in
securing funding through municipal participation, and that private
financing with a subsequent conversion to industrial revenue bonds
seems a viable approach. While some larger cities would obviously
generate sufficient solid waste to power a 1200 TPD plant, the com-
bination of trash quantity and a steam customer large enough to
utilize the output of the plant may often be found only in the suburban
communities which, therefore, makes the area or regional approach
the logical choice. We have come to realize that we can effectively
and economically operate water supply and sanitary sewage systems
on a regional basis, but most small communities appear to be extremely
provincial in their approach to solving their solid waste dilemmas.
This is not hard to understand when we recall our solid waste has been
buried inexpensively in landfills; and because the pickup and transpor-
tation constituted the major cost element, landfill sites were generally
found within the towns' borders. A need exists to educate local
officials that the solution to solid waste disposal needs to go beycnd
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those borders and economies and an improved system can be achieved
on a regional basis.
It is in this area that the states, rather than the federal
government must display some leadership and direction through better
enforcement of existing regulations governing landfill operations
in order to adequately control open dumping which gives properly
run sanitary landfills a bad name. The State must also provide
incentives for communities to form regional solid waste alliances.
Appropriate sites can be secured by state governments through eminent
domain takings where no one community could likely have that power for
a regional facility.
The greatest contribution state governments can make to the
long-range encouragement of energy recovery from our solid waste
would be to streamline and simplify the morass of approvals necessary
to bring such a plant on line. The ever-increasing regulatory
agencies involved in granting approval for construction and operation
is frightening and must be simplified. Of course, new concern and
control is necessary due to our expanding population and worldwide
environmental considerations, but more than often State agencies
have conflicting regulations or overlapping approval responsibilities
which must be simplified if we are to avoid discouraging and, in fact,
preventing many worthwhile projects.
Our present regulatory agencies are structured primarily for the
protection of our health and safety and do not respond easily to new
techniques or dimensions of scientific advancement. Decisions are
often required during the design and construction stages of multi-
million dollar projects that state agencies are incapable of responding
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to in a timely fashion. Because we live in an age of protest, they
are sensitive to all objectors which is our democratic way of life,
but some means must be found to avoid the unfair delay of projects
benefiting many because of the often ill-considered protests of a
few. A fair balance must be struck more quickly than is frequently
possible at present.
If the granting of permits can be simplified without sacrificing
protection for the public, a great deal of needless time and expense
can be avoided. To illustrate the point, the utility bridge required
to cross the Saugus River to transport the steam to the customer
required approval of eight agencies or Government Legislative bodies.
The approval process starts with the town or city's conservation
commission which must send a favorable recommendation to the town's
board of selectmen, or a city's city council or board of aldermen.
Their formal approval is required before The State Department of Public
Works - Waterway Division - will act on an application for construction.
But in the case of the RESCO Bridge, it is a fixed span over a river
that has drawn bridges both up stream and down; and, therefore, a
special act of The Legislature of The Commonwealth of Massachusetts
was required before DPW could act. Upon passage of that special act,
they reviewed the request after examining the Environmental Impact
Statement which is required for the bridge, as well as the entire
project. Once finally approved by DPW, they sent their recommendation
to the Corps of Engineers who have final authority. Because it is
a navigable waterway, the corps would not take any action until the
Coast Guard had sent in their recommendations and approvals which
they would not do until after a public hearing was held. This process
and the subsequent receipt of the necessary permits consumed over one
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year of time and numerous hours of testimony time by engineers,
lawyers, and officials of the company. When one realizes the entire
process could have been stymied by one partirae City Park Attendant
who was Chairman of the City Conservation Commission, it is apparent
our precedures for approval must be modernized if we are to benefit
from projects which can improve our environment and preserve our
precious resources.
Our present regulations submit a developer to an unreasonable
risk in that the Massachusetts Department of Public Health - Division
of Air Quality - requires the submission of a complete set of drawings
and specifications including detailed operating and maintenance
procedures before they will act on the approval of the necessary
construction permit. Because of the uniqueness of this project,
the department agreed to allow five-phase submissions for approval
covering the following subdivisions of design: (a) site work and
foundations, (b) substructures, (c) superstructures, (d) machinery,
and (e) operational and maintenance procedures. While construction
is proceeding on the project, committing many millions of dollars,
final approval of the plant design has not yet been received. The
state has informed RESCO that no further phased approvals will be
permitted by the department on subsequent projects, thereby requiring
the expenditure to provide complete drawings and specifications before
any approvals are granted. What reasonably prudent investor will take
that risk in the future?
There is a need for legislation which will create a centralized
state licensing board with the responsibility to protect the public
health and safety, but which also has the power to expedite certain
regulations or procedures in the overall best,interests of the public.
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Federal legislation, recently adopted will enable a growing
number of communities to plan comprehensive solid waste management
programs and investigate resource recovery options available to them.
A number of localities have already been involved in planning and
procurement activities. From our experiences and theirs we know
that the planning process for comprehensive solid waste management
services, particularly those built around resource recovery, is often
a time consuming and frustrating experience. To facilitate responsible
private industry's participation in providing recovery services a
number of key issues should first be resolved. It is here that the
Resource Conservation and Recovery Act of 1976 can be of assistance
in assuming that State and regional plans are responsive to eliminating
the many roadblocks hindering development of these facilities.
Those state plans must assure a quantity of waste supply sufficient
for the scale of the proposed facility. The economics of resource
recovery partially depend upon income obtained for the disposal services
rendered to the community. There are a number of different approaches
to assuring sufficient waste for the resource recovery plant. In
Boston, we competed in the open marketplace with landfill and other
disposal operations. We feel this to be the best way to secure a
long-term waste supply at a reasonable, controlled cost to the public.
Other ways are being considered. They include districting, franchising,
and otherwise mandating the flow of refuse within an area. In each
case a community must make a long-term commitment to supply a certain
quantity of refuse necessary to defray the capital and operating costs
of the facility. From the communities standpoint, making these
assurances will often depend upon whether the disposal services being
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offered at the resource recovery facility are cost competitive and
as reliable as other disposal options. Congress has recognized the
importance of long-term waste supply commitments by providing in
Sec. 4003(5) of the Resource Conservation and Recovery Act of 1976
that local governments be given the legal authority to enter into
long-term supply agreements with the private sector.
A second key issue concerns the nature of energy markets for
the combustible fraction of solid waste -- markets for steam or
electrical energy of fuel produced by the resource recovery process.
As a general rule, income from energy production and dumping fees
should meet the capital and operating costs for the resource recovery
facility. The availability of long-term, stable energy markets will
reduce the need to rely on dumping fees to meet plant costs. In the
recently passed legislation, Congress, recognizing the importance of
recovery markets to the commercialization of proven resource recovery
technology, has mandated the Secretary of Commerce to develop ways
to encourage markets for recovered resources.
There are, of course, other issues which are equally important
in evaluating the feasibility of establishing resource recovery
services. For example, are local governments able to negotiate for
such services or are they limited, by law, to procurements made
through a competitive bids procedure? Very often it will be difficult
for a city to adequately evaluate resource recovery services if it
is limited to accepting the lowest bid quoted in terms of a net dumping
fee.
Before closing, there is an important observation to make about
the potential for solving our solid waste disposal requirements
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through resource recovery. Even with the most favorable markets for
recovered energy and products it is likely that there will be residue
from the process which will require land disposal. In addition, most
technologies being offered are unable to handle the wide variety of
volatile, toxic and otherwise hazardous industrial solid waste materials.
Hence, state and local governments should be under no illusion that
resource recovery means the end of land disposal for solid waste. These
are a necessary adjunct to a totally integrated resource recovery plan.
The RESCO plant demonstrates that an industry can benefit
from the energy to be derived from the solutions of our mounting
solid waste problem. Regional associations of suburban communities
appear to be as logical to solve our solid waste problems as we have
found them in serving our other needs, such as water, sewerage, and
transportation systems. However, they often lack the means to finance
these facilities and by solicitinq proposals to desian, build and
operate the facility, they can make -judicious use of private capital,
possibly converting to industrial revenue bonds which gives ownership
of the facility to the regional group after the amortization period.
The Europeans have been an energy-short society for years,
and they have learned to recover the precious energy from solid
waste that we bury daily. The technology is not new. It's time
we removed the needless bureaucratic roadblocks preventing the use
of that technology. To those of us who lived through it, it appears
the whole process currently is out of balance, and it is the
public -- all of us -- that suffers as a result.
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THE IMPACT OF SOURCE SEPARATION AND WASTE REDUCTION
On THE ECONOMICS OF RESOURCE RECOVERY FACILITIES
John H. Skinner*
Background and Introduction
The rising costs and decreased availability of land, energy and raw
materials have created pressures for the recovery and reduction of solid
waste. In recent years communities across the nation have considered
various options to reduce solid waste disposal requirements and simultaneously
conserve energy and materials. These options can be grouped into the
following three broad categories.
1. Haste reduction is defined as the reduction or prevention
of waste at its source, either through the redesign of
products or the reduction of product consumption. Examples
include the use of reusable products or products with increased
durability and longer lifetimes.
2. Source separation is defined as the separation of waste
materials at the point of discard followed by separate
collection and recycling. Source separation currently
accounts for virtually all post-consumer solid waste
recycling. Examples include collections by charitable,
service and religious organizations, community and industry
recycling centers, and municipal separate collection programs.
3. Mixed waste recovery is the processing of mixed municipal waste
to recover useful materials or energy. A number of technologies
have been developed and are being applied for this purpose. Host
of them involve energy recovery through either waterwall
combustion, production of solid refuse-derived-fuels or
pyrolysis to produce liquid or gaseous fuels. Mixed
waste recovery systems also include a number of unit processes
to recover metals and glass from mixed refuse.
* Dr. Skinner, Deputy Director, Resource Recovery Division, Office
of Solid Waste Management Programs, U.S. Environmental Protection Agency,
presented this paper at the Fifth National Congress on Waste Management
Technology and Resource and Energy Recovery sponsored by the flational
Solid Waste Management Association. Dallas, Texas, December 9, 1976.
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In recent years there has developed a debate concerning both the
relative importance and the potential conflicts between these three
options. Part of this debate has viewed these options from a national
perspective and has explored the importance of each in dealing with the
national solid waste management problem. Another part of the debate
has focused on the choices and conflicts in the implementation of
combinations of these options at the local level. This later issue will
be the r^in subject of this paper. However, before proceeding along
these lines, a few of EPA's major findings concerning the national
policy significance of waste reduction and resource recovery will be
stated. This is important to put this subject in the proper perspective
because a number of prevalent misconceptions have developed on this
issue. One is that large scale mixed waste processing systems can be
expected to solve the Nation's solid waste disposal problems in the
forseeable future. Another is that the other two options - waste reduction
and source separation - are of only nominal or symbolic significance.
In this regard EPA has found that:l>2>3
- Even with an optimistic increase in the number of cities
installing mixed waste recovery systems, the total national
solid waste disposed of annually will increase significantly
by the mid-1980's.
- Many mixed waste processing technologies are still in the develop-
mental stage. While accelerated implementation is expected in
the future, it is not likely that more than 10 to 20 percent of
the nation's solid waste will be processed in such plants in the
next decade.
Source separation and waste reduction measures can make
quantitatively significant reductions in solid waste disposal
requirements. However, there are market and institutional
barriers to these options.
- Increased adoption of all three approaches is necessary in
order to have a large positive impact on the amounts of solid
waste disposed of nationwide. Mo single approach in itself
will yield desired reductions in waste disposal levels.
The basic conclusion on this issue is that from a national perspective
there is no choice between the various forms of resource recovery
and waste reduction. No single "solution" can "do it all" and all
three options taken together will not obviate the need for well-designed
land disposal sites.
Turning now to the second issue which has been raised, concerning
the potential conflict between the local implementation of the three
options. Waste reduction, source separation and mixed waste recovery
each offer a number of different benefits to the local decision maker
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and involve different costs. A few examples will make this clear.
Waste reduction and source separation will reduce the requirements for
both disposal and collection of solid waste, while mixed waste processing
can only reduce disposal requirements. Conversely source separation
involves requirements for collection and transportation of separated
materials. Source separation is generally less capital intensive than
mixed waste recovery, but large scale processing facilities enjoy certain
economies of scale. Some waste reduction options, could effect product
consumption levels, prices and litter rates, while source separation and
mixed recovery may not impact these items at all. Source separation may
result in recovering a few materials at higher economic values as compared
to mixed waste processing. On the other hand, processing facilities
employing energy recovery may result in a higher recovery rate for more
of the waste stream. Any decision to locally implement combinations of
these programs should be made from a comprehensive analyses considering
overall costs and benefits. In fact, the recently passed Resource
Conservation and Recovery Act of 1976 recognizes the importance of such
analyses and mandates:
"research and studies concerning the compatability of front-end
source separation systems with high-technology resource recovery
systems."^
This paper will address only one aspect of this subject, the
impact of source separation and waste reduction programs on the economics
of mixed waste recovery plants. Such programs could cause significant
reductions in the quantity of recyclable materials in the waste stream.
Since such materials provide a source of supporting revenues for mixed
waste recovery facilities, their removal could impact adversely on plant
economics, especially if such programs are instituted after a plant has
been designed and constructed. This paper will present a preliminary
estimate of the order of magnitude of some of these economic impacts and
a discussion of their significance and relevance to recovery plant
implementation decisions.
In the following sections two types of programs are analyzed:
1. paper recycling programs and their resulting reduction in
the heating value, energy content and value of solid waste
a fuel, and
2. metal and glass reduction and recycling programs and their
resulting decrease in recycled material revenues for mixed
waste recovery plants.
It must be re-emphasized that the analysis will not consider the
relative costs and benefits of paper separation and container reduction
as compared to recovery of these products through mixed waste processing
plants. Rather the analysis will consider only the impact of such
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programs on recovery plant economics. Even if the impact on plant
economics is negative it would be beneficial for communities to carry
out such programs if the overall system economics is improved or if the
benefits exceed the additional costs.
Paper Recovery Through Source Separation
Quantities and Recycling Levels. Wastepaper makes up approximately
32 percent by weight of residential and commercial solid waste* (Table
1). Several grades of wastepaper have significant potential for source
separation and recovery (Table 2). Old newspaper represents approximately
20 percent of the wastepaper discarded in solid waste and most of this
is generated from residences and households and is easily separated from
other wastes. Old corrugated represents approximately 25 percent of
wastepaper discards and most of this is generated in commercial and
industrial establishments. Corrugated recovery from such sources has
been practiced for years. Office papers represent approximately
13 percent of discarded wastepaper. In the past few years a number of
office buildings have instituted programs to separate high grade office
papers for sale and recycling. The theoretical maximum potential recovery
level for all three of these grades has been estimated to be approximately
50 to 60 percent.'>P-48 However, actual recovery levels that have been
experienced have been much lower than this. Municipal separate collection
programs (collecting primarily newspapers) have reported recovering from
5 to 20 percent of the total wastepaper available.5 While individual
office buildings have reported paper recycling levels ranging from 10
percent to as high as 70 percent the overall level of office paper
recycling in most communities is probably very low. Other wastepapers
such as books, magazines and miscellaneous packaging and other papers do
not ..offer significant potential for recycling because of their high
contaminant levels, dispersed generation and heterogeneous nature.
Paper Value as a Fiber. A key factor in decisions whether to
recover wastepaper as a fiber is the market prices for wastepapar.
Wastepaper prices vary with grade, location and time and prices ranging
from a few dollars per ton to over $100 per ton have been observed
(Table 3). For certain high grade papers such as sorted white ledger (a
grade which can be obtained from office paper separation programs) the
fiber value is probably high enough to make source separation economically
viable under most circumstances. For other grades such as mixed wastepaper,
old news and corrugated, the fiber value depends upon local paper markets,
and could vary significantly as prices change over time. In the periods
Throughout this report solid waste composition percentages are
defined as national average disposal levels after national average
recycling rates have been subtracted. Similarly recycling and recovery
percentages are defined as increments over and above present national
average recycling levels and expressed as a percent of national average
disposal levels.
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when paper markets are strong, these grades may be extracted for recycling
through increased collections by community groups, private firms or
municipalities. At times of low paper prices such papers may be discarded
with other municipal wastes. It is these shifts in the price of wastepaper
in the local market areas, and the resulting increase or decrease in
paper recycling levels that may give rise to some degree of uncertainty
in the economics of energy recovery plants.
Impacts on Energy Content. In order to illustrate the impact of
paper removal on the energy content of solid waste two situations will
be described. The first situtation is for a plant receiving wastes from
a service area with a fixed or constant quantity of waste. For example,
this would represent a plant serving a fixed population community with
a constant per capita waste generation rate. Prior separation and
recovery of paper would reduce the total amount of solid waste received
by the plant and the energy recovered (and energy revenues) would be
reduced in direct proportion to the paper removal. The order of magnitude
of this effect is presented for various paper recovery rates on Table 4.
The reduction in energy available from the wastes generated in a
fixed service area does decrease significantly (greater than 20 percent)
at very high paper recovery rates. However, in the range of actual
paper recovery rates experienced (10 to 20 percent paper recovery) the
reduction in total energy available is less than 10 percent.
The second situation analyzed is for a plant with an expandable
service area, i.e., a plant which can expand its service area in order to
fully utilize plant capacity. The fixed-no growth service area is an
unlikely situation for most parts of the country. Most plants would
have some opportunity to compensate for waste reductions from paper
separation by expanding the service area to a larger population. Such
reductions would also be offset over time by growth in the per capita
waste generation rate. However, even in these situations there would be
a reduction in total energy recovered. Since paper has a higher heating
value than the average for mixed municipal waste, its removal results in
a decrease in the average heating value of the remaining waste. This
means that even if plant throughput was not reduced by a paper recovery
program, less steam or fuel would be produced for every ton of waste
processed. These effects are also shown on Table 4. The reduction in
heating value is minimal (less than 10 percent) even for high paper
recovery rates. Removal of paper does not result in a significant
decrease in the heating value of the remaining waste. Solid waste with
some of the paper removed will still burn.
Economic Impact Estimates. In order to illustrate the order of
magnitude of economic impacts of paper separation on energy recovery
plants, the results of a simple calculation are presented on Table 5.
This calculation makes a number of assumptions concerning fuel price,
energy recovery efficiency, heating value and processing costs as shown
in the table. While these are not the actual figures for any particular
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plant, they are within the range of values that have been presented for
various energy recovery systems. The results are presented in terms of
the disposal charge or tipping fee per ton of solid v;aste that would
have to be charged at the plant in order to cover fixed processing
costs. Results are presented for both a fixed service area and a
service area which can be expanded to maintain plant capacity as paper
is removed.
The results show that for the expandable service area the increase
in disposal charge is about $.65 per ton for the highest paper recovery
rate. Far the fixed service area, since the energy recovery decrease is
greater and the fixed processing costs must be spread over a smaller
tonnage, the disposal cost increase is greater. For the highest paper
recovery rate the disposal charge increases about 152.85 per ton. For
the range of paper recovery rates that have been experienced in municipal
programs (10 to 20 percent) the disposal charge increases by $.70 to
$1.35 per ton.
The actual numerical results derived above should be used with
caution since they are based upon a number of assumptions which may or
may not be valid for other resource recovery plants. However, the
results do illustrate several interesting points. Paper separation
programs that are instituted in areas where there are existing energy
recovery plants may reduce both the capacity utilization and energy
revenues of such plants. However, for plants that can expand their
service areas to compensate for waste reductions from paper separation,
the disposal charge increase is likely to be insignificant (much less
than $1 per ton). For plants with fixed service areas, disposal charges
could increase several dollars per ton at very high paper recovery
rates. However, for "typical" paper recovery rates the disposal charge
increase would be much smaller (of the order of $1 per ton) even for
fixed service area plants. For plants that are built after the institution
of paper separation programs, these impacts can be reduced even further
by designing such plants for full capacity utilization. The major
negative economic impact occurs for a plant that suffers a precipitous
decline in delivered tonnage at a rate that cannot be compensated for by
expansion to additional sources of waste. It is this situation that
should be of primary concern to owners and operators of mixed waste
processing plants.
Metals and Glass Separation or Reduction
Alternatives for Metal and Glass Recovery. Metals and glass make
up approximately 20 percent of municipal solid waste by weight. Many
mixed waste recovery plants are considering extraction and recovery of
some of these fractions. Ferrous metals recovery through magnetic
separation is a commercially established technology which will probably
be widely used in most recovery plants in the future. However, glass,
aluminum and other nonferrous metals recovery is in the developmental
and experimental stage. There are a number of uncertainties concerning
technologies. Markets for recovered glass and nonferrous ruetal resources,
have just begun to be developed. Given this situation any analysis of
the impacts of material separation or reduction programs becomes somewhat
tentative, because the economics are uncertain on both the cost and
revenue side.
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There are several types of programs that could effect the
recovered materials revenues from mixed waste recovery plants:
1. Glass and metal source separation. While several communities
have experimented with programs for the source separation
and separate collection of glass and metals this option has
not been practiced widely to date.1
2. Aluminum can recovery programs. The aluminum industry has
instituted a can collection program that has resulted in
the recovery of 25 percent of all aluminum cans nationwide
and much higher rates in local situations."
3. Beverage container deposit programs. Four States, Oregon,
Vermont, Michigan and Maine have passed mandatory beverage
container deposit laws. In Oregon and Vermont where the laws
have been in place for several years very high return rates
(greater than 90 percent) for all beer and soft drink
containers have been experienced with similar reductions in
container waste generation rates.
For purposes of illustrating the impacts of such programs on the material
revenues of mixed waste processing plants, the beverage container deposit
case will be used as a model. On the average, beverage containers make
up 45 percent of the glass, 38 percent of the aluminum and 15 percent of
the ferrous metal in mixed municipal waste (Table 2). It will be assumed
that container deposit programs will result in a complete elimination of
the beverage container fractions from the waste stream. While this is
certainly an exagerated impact it serves to maximize the reductions in
recovery plant material revenues.
Impact on Gross Revenues. Estimates of the gross revenue contribu-
tions for metals and glass recovered in a mixed waste processing plant
are shown on Table 6. Gross revenues represent simply the recovered
material sale prices and do not account for the costs of extracting and
recovering these commodities. Because of the uncertainties and variations
in some of these numbers the estimates are shown as a range rather than
a point value. These variations are due to differences in:
1. recovery efficiences which depend upon the technology
employed and the quality of the product recovered, and
2. recovered material sale prices which depend upon the markets
and the product specifications.
The numbers shown represent the range of efficiencies and prices that
have been discussed in the resource recovery literature. The upper
range represents pushing the technology to its limits and receiving top
prices for the products. The lower range represents minimum efficiencies
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and relatively poor market conditions. The gross revenues from ferrous
metals, glass and aluminum range from $2.75 to $6.00 per ton of solid
waste processed. All other things remaining constant, an elimination of
the beverage container fraction would reduce these gross revenues by
$.70 to $1.60 per ton of waste processed. However, as will be discussed
in the following sections, removal of glass and aluminum beverage containers
may reduce revenues from other glass and aluminum products. Moreover,
conclusions regarding the impact of beverage container policies on the
overall economics of mixed waste processing plants must consider the
net revenue contributions after processing costs are accounted for.
Impact on Net Revenues. Net revenue calculations are subject to
wide margins of uncertainty. There has been very little analysis of the
costs of processing specific components of the waste stream. It is very
difficult to separate the incremental costs of steel, glass and aluminum
recovery from the overall plant cost figures. It is even more difficult
to evaluate how these costs might change as a function of changes in the
quantity and composition of the wastes processed. Therefore, the cost
presented are a very rough first approximation.
The recovery plant considered is a refuse-derived-fuel plant that
recovers ferrous metals by magnetic separation and glass and aluminum by
a combination of heavy media separation, froth flotation, optical sorting,
and electrostatic separation. The approach used is to estimate only the
incremental cost of separating the ferrous, glass and aluminum fractions.
This means that the basic costs of shredding and air classification have
not been allocated among these products. This is the correct approach
in determining whether or not materials recovery subsystems should or
should not be included in a project—that is in terms of their incremental
contributions to processing costs and net revenues. The results are
shown on Table 7.
The incremental process costs for ferrous metals recovery have been
estimated separately. Glass and aluminum recovery share many of the
unit processes in commofr making it impossible to separate the processing
costs for these two materials from each other. These costs estimates
include fixed and variable operating costs and capital costs amortized
over the plant 1ife.
The incremental process costs of ferrous metals recovery are
estimated to be in the range of $.50 to $1.00 per ton of solid waste
processed and the costs of glass and aluminum recovery are estimated
to be from $1.70 to $2.00 per ton of solid waste processed. These
process costs, when subtracted from the high gross revenue estimates
derived previously result in net revenue contributions for ferrous
metals recovery ranging from $2.20 to $2.70 per ton and for glass and
aluminum recovery ranging from $.85 to $1.15 per ton. (It should be
noted that for the low gross revenue estimates aluminum and glass
recovery is not economical, i.e. the incremental processing cost exceeds
the gross revenue contribution).
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Removal of 15 percent of the ferrous metals would probably not
effect processing costs significantly and recovery of the remaining 85
percent would still be economically feasible. Therefore, the impact of
removal of ferrous beverage cans on ferrous metal revenues is roughly
equal to the reduction in gross revenues which is about $.50 per ton.
For glass and aluminum recovery the effect of beverage container
removal is more complicated to analyze. Many aluminum recovery subsystems
are more efficient with respect to recovery of aluminum cans than other
aluminum products (such as foils). A given reduction in aluminum cans
could result in a much greater reduction in the percentage of total
aluminum recovered. In the extreme, removal of the aluminum can could
make recovery of the other aluminum fractions unprofitable. Also, the
economic feasibility of glass recovery is closely linked to aluminum
recovery as many of the processing steps are combined for the two materials.
Therefore, the impact of removal of glass and aluminum containers
could range between two extremes. In the best situation net revenues
would be reduced only in proportion to the reduction in the container
fractions and would range from $.35 to $.45 per ton of solid waste
processed. In the worst situation removal of the glass and aluminum
container fractions would make other glass and aluminum recovery economically
unfeasible and the net revenue loss would be from $.85 to $1.15 per ton
of solid waste.
In summary, for plants recovering only ferrous metals, the removal
of beverage container materials could reduce net revenues by roughly
$.50 per ton of solid waste processed. For plants also recovering
aluminum and glass, and receiving high gross revenues for these products,
beverage container removal could reduce net revenues by an additional
$.35 to $1.15 per ton. As for the paper separation analysis, these
results could be extended to estimate the disposal charge impact for
both fixed and expandable service areas. It was decided that this
further refinement would not be meaningful due to the uncertainties in
these numbers in the first place. The net revenue reductions approximate
the disposal charge increases.
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Conclusions
The previous sections presented estimates of the effect of paper
separation programs and beverage container reduction programs on the
economics of mixed waste recovery facilities. These estimates are based
upon a number of assumptions concerning the composition of the waste
stream, technology performance and costs, and recovered material market
prices. As was pointed out, there is a certain amount of variability in
each of these parameters and the results could be different for plants
employing different technologies or for plants located in different
parts of the country.
The analysis showed that the impact of paper separation programs on
plant disposal charges could range from a few cents per ton to several
dollars per ton depending upon the paper recovery rate and the plant
capacity utilization. However, considering the paper recovery rates
that have been experienced, and considering that many plants should be
able to compensate for waste reductions by expansion of service areas;
the likely increase in disposal charge for most plants would probably be
much less than $1 per ton.
The analysis also showed that beverage container reduction programs
could reduce recovery plant net revenues from $.50 per ton to over $1.50
per ton depending upon the technology performance and recovered material
market prices. For plants recovering only ferrous metals the impact
would be in the lower end of this range. Revenue reductions in the
upper range would only occur for plants recovering glass and aluminum as
well, and achieving high recovery efficiencies and receiving high market
prices. Therefore, for most recovery plants the likely impact of beverage
container reduction programs would probably be much less than $1 per
ton.
Given the uncertainties that exist in resource recovery technologies
and markets, possible cost changes within the range of $1 per ton should
not be determining factors in community decisions. Future costs cannot
be projected to this degree of accuracy. Small changes in construction
costs, interest rates and material and energy prices could produce
comparable effects.
Of course, there is the possibility that resource recovery markets
and technologies might develop to the point that the impacts of separation
and reduction programs could be greater than what is presently considered
likely. This raises the question of what actions, if any, should be
taken by resource recovery plant operators to guard against such negative
economic impacts. Should communities contracting with recovery plants
be prohibited from engaging in municipal source separation programs?
Should there be penalties if a community (or State) passes a returnable
beverage container ordinance? It is believed that such drastic measures
are not necessary to protect resource recovery plant investments.
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It is important to realize that over the 20 to 25 years lifetime of
a mixed waste recovery plant there will probably be a number of changes
that would impact on plant economics. Many of these changes will be
"uncontrollable" and will be brought about by private sector free market
actions. For example, increased use of plastic beverage containers
could reduce the metal and glass content of solid waste and produce
effects similar to beverage container deposit programs. Private sector
paper recycling could produce effects similar to municipal source
separation programs. Changes in the prices of fiber and energy could
effect the relative economics of paper separation versus energy recovery.
Recovery systems that are being built today are going to have to be
designed to accomodate such changes.
Mechanisms and institutions need to be developed for managing these
uncertainties and share some of the potential risks and benefits between
local governments and recovery plant owners and operators. Communities
should try to maintain the flexibility to implement new programs that
would improve the overall economics and environmental impacts of their
solid waste management systems. Contract provisions or agreements that
foreclose future improvements are unwise. However, provisions that
equitably allocate costs and responsibilities are also a necessity. The
potential uncertainties concerning public policies for source separation
and waste reduction programs should be handled within such a framework.
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Table 1
Material Composition of Residential
and Commercial Solid Waste*
Material Percentage
Paper and Paperboard 32.3
Glass 9.6
Ferrous 8.4
Aluminum 0.8
Other Monferrous 0,4
Plastics 3.7
Rubber and Leather 2.6
Textiles 1.4
Wood 3.6
Food Waste 16.8
Yard Waste 19.0
Miscellaneous Inorganics 1.4
100.0
*U.S. Environmental Protection Agency, Office of Solid Waste Management
Programs. Fourth Report to Congress, Resource Recovery and Waste Reduction.
Draft, November 1976.
Mote: Estimates on an "as generated" weight basis assuming normal moisture
content of material prior to discard.
These are national average disposal levels after national average
recycling rates have been subtracted.
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Table 2
Selected Product Composition of Residential
and Commercial Solid Waste*
Material, Percent of
Total Solid Haste
Paper and Paperboard 32.3
Newspaper 6.0
Office Paper A.I
Corrugated 8.2
Books and Magazines 2.6
Other Packaging 8.4
Other Nonpackaging 3.0
Glass 9.6
Beer and soft drink containers 4.3
Other containers 4,5
Other products .8
Ferrous 8.4
Beer and soft drink containers 1.2
Other containers 3.2
Durable goods and other products 4.0
Aluminum 0.8
Beer and soft drink containers 0.3
Foil 0.3
Other Products 0.2
*U.S. Environmental Protection Agency, Office of Solid Waste Management
Programs. Fourth Report to Congress, Resource Recovery and Haste Reduction.
Draft, November 1976.
Note: Estimates on an "as generated" weight basis assuming normal moisture
content of material prior to discard.
There are national average disposal levels after national average
recycling rates have been subtracted.
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Table 4
The Impact of Paper Recovery on the
Energy Content of Solid Waste
Paper Recovery
Rate
(percent)*
10
20
30
40
Fixed Service
Area Reduction in
Energy Available
(percent)**
5.3
10.8
16.0
21.5
Expandable Service
Area Reduction in
Energy Available
(percent) +
2.2
4.6
7.0
9.9
*Defined increments above present national average recycling rates,
as a percent of present national average rate of wastepaper disposal.
**Reduction in energy content of a fixed quantity of waste caused
by the removal of paper.
+Reduction in average heating value per unit weight of waste.
Calculated from data by Niesson, W. R. and S. H. Chansky, "The Nature
of Refuse", Proceedings of 1970 National Incinerator Confernce.
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Table 5
Impact of Paper Recovery on the Disposal
Charge of an Energy Recovery Plant
Disposal Charge (per ton of solid waste)
Paper
Recovery Rate*
0
10
20
30
40
Expanded
Service Area
8.50
8.65
8.80
8.95
9.15
Fixed
Service Area
8.50
9.20
9.85
10.55
11.35
Assumptions:
1. Energy revenues $1.00/million BTU.
2. 65 percent of input waste is converted to energy.
3. Heating value of solid waste with no paper recovery 10 million
BTU/ton.
4. Fixed costs (capital costs and fixed operating costs) of $15 oer
ton of daily plant capacity.
5. Other materials revenues are not included.
*Defined as increments above present national average recycling
rates, as a percent of present national average rate of wastepaper disposal.
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Table 7
Net Revenues from Metal and Glass Recovery
($/ton of solid waste)
Ferrous Metals Glass and Aluminum
Recovery __ Recovery __
Gross Revenues $3.20 $2.85
(high)
$-50 to $1.00 $1.70 to $2.00
$2-20 to $2.70 $.85t0$1.l5
*Derived from: Resource recovery engineering and economic feasibility
for either a 650 or 1300 ton per day processing facility. National Center
for Resource Recovery, Inc. Report prepared for the Metropolitan Washington
Waste Management Agency. Washington, D.C., January 1975.
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References
1. U.S. Environmental Protection Agency. Third Report to Congress,
Resource Recovery and Haste Reduction. Environmental Protection
Publication SW-161. Washington, U.S. Government Printing Office,
September 1975.
2. Skinner, J. H. Reduce the Incentives to Waste, Environmental
Protection Publication SW-500. U.S. Environmental Protection
Agency, Washington, D.C., September 1975.
3. Hutnber, Nicholas. Waste Reduction and Resource Recovery - There's
Room for Both. Waste Age. November 1975.
4. The Resource Conservation and Recovery Act, Public Law 94-580,
October 1976. Section 8002(e).
5. Analysis of Source Separate Collection of Recyclable Solid Waste -
Separate Collection. SCS Engineers. U.S. Environmental Protection
Agency Study 68-01-0789. August 1974.
6. Optimization of Office Paper Recovery Systems. SCS Engineers.
U.S. Environmental Protection Agency Study 68-01-3197.
7. Hansen, P. and J. Ramsey. Demonstrating Multi-material Source
Separation in Sommerville and Marblehead, Massachusetts.
Waste Age, February 1976.
8. Press Release, The Aluminum Association, New York, Hay 11, 1976.
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REGIONALISM: ITS ROLE IN RESOURCE RECOVERY
Stephen G. Lewis
The Mitre Corporation
THE ISSUE OF REGIONALIZATION
Over the past three or four years we have learned a few things about
planning for resource recovery. First, and most important, we have
learned just how difficult it really is to plan and establish a facility
that, in reality, is a complex manufacturing plant processing raw materi-
als, solid waste, provided for the most part by local governments. From
these raw materials the plant produces energy products for sale such as
steam, gas, oil, refuse derived fuel, or electricity, and materials such
as ferrous metals, aluminum, or glass. Because of the high cost of these
plants, the trend is to finance them through the issuance of revenue
bonds supported by financially strong revenue streams under contract. The
revenue streams are derived from the sale of energy and materials, and
fees for refuse disposal from local governments and private refuse collec-
tors. The job of putting the system together requires selection and nego-
tiation of markets, technologies and capable private firms for design, con-
struction, and operation. It also requires selection of sites and defini-
tion of long term commitments to deliver refuse to the facility.
One conclusion from this is that the resource recovery planning pro-
cess requires skills, time, money, conviction, and political and entre-
preneurial strength not possessed by most local governments. Another con-
clusion is that a long term and reliable energy customer is needed, as well
as sites for the processing facility and for disposal of process residues
and emergency use. Both the energy customer and the sites must be within
the boundaries of the local jurisdiction planning the facility, and most
local jurisdictions are hard pressed to come up with these. A final con-
clusion is that there must be sufficient refuse generated within the
jurisdiction to supply the type of facility that is otherwise appropriate
for the area, based on energy and materials markets, site locations, and
private industry interest.
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These conclusions point to the need in a number of cases for local
governments to join together in some manner and regionalize so that they
can expand the market opportunities, the siting options, or increase the
amount of waste available for processing to a level where the capital in-
vestment for the facility is warranted. It seems a pity that resource
recovery implementation is going to be dependent upon regionalization,
since it is such a difficult thing to bring about. On top of the diffi-
cult technical and financial planning tasks required for resource recovery
itself, in regionalization we must also address what may turn out to be an
even more complex political and organizational planning task.
Certainly, there is nothing new about forming regional organizations
or cooperative efforts. In water supply, wastewater treatment, delivery
of educational services, local purchasing, and even police and fire pro-
tection there are numerous experiences to demonstrate that certain gov-
ernment functions or services can best be performed on a broader metro-
urban regional basis. But the diversity of local environments makes it
unwise to expect that an effective approach for one area will necessarily
be applicable to another. It is equally unwise to believe that such new
government forms are easy to define and create.
The purpose of this paper is to illustrate why regionalization in
solid waste disposal and resource recovery is important, to discuss the
approaches that can be used and the problems in achieving them, and to
make some general recommendations which will hopefully speed up progress.
THE SOLID WASTE RESPONSIBILITY OF LOCAL GOVERNMENTS
In the United States about 70% of the people are packed into densely
populated urban areas. About 30% of these people live in the central city
itself while the remainder (40%) live in communities surrounding the cen-
tral city. For the most part, local units of government are individually
small. Although there are almost 2000 cities with a population over
10,000, almost 60% of these are actually smaller than 25,000 people. In
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total we have more than 30,000 units of local government. It is clear
that, by far, the majority of these are extremely small. Individual
counties are not much larger, with almost 80% of the 3000 counties having
a population of less than 50,000 people.
Although figures are not very good, we have reason to believe that
many thousands of local governments are themselves responsible today for
their own solid waste disposal, and thus will have a key voice in what
their new procedure will be when the current one is no longer available.,
Estimates indicate that there are over 18,000 land disposal sites in the:
*
country, of which some 6000 are state approved . Almost 4000 of these
are publicly owned and operated. Obtaining solid waste disposal capacity
**
is certainly a problem, since in a 1973 survey local governments ranked
the need for disposal sites their number one problem, and 46% of the gov-
ernments reported they had less than five years of disposal capacity re-
maining.
In summary, there are thousands of local governments responsible for
deciding how to dispose of their solid wastes. Among their decisions is
the one to regionalize or to find a solution by themselves.
THE REGIONALIZATION ARGUMENT
The basic argument for regionalization in solid waste disposal and
resource recovery is that the function is a capital intensive one that,
within a certain size range and in the majority of cases, can be performed
at a lower unit cost at larger scales. A second, but no less important
argument, is the need to provide both a site or sites for processing as
well as disposal of residue and nonprocessable items, and the possible
need for close proximity of processing with a secure energy customer, such
Waste Age,"Survey of the Nation's Land Disposal Sites", January 1975,
p.17.
National League of Cities-U.S. Conference of Mayors, "Cities and the
Nation's Disposal Crisis", March 1973.
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as a user of steam or gas. A third and more philosophical argument — but
one which may indeed be the most important -- is that the solid waste man-
agement objectives of this nation will not be served be providing resource
recovery solutions for only those few local governments who happen to have
the right conditions for it within their borders.
The realities of these arguments have been recognized by many:
• National League of Cities, Cities and the Nation's Disposal
Crisis. 1973, p.7 "The solutions to [solid waste] prob-
lems require: (1) resources and support functions that ex-
ceed the internal capability of cities, (2) available land
areas for disposal, which many cities increasingly lack
within their political boundaries."
• U.S. Environmental Protection Agency, Decision-Makers Guide
in Solid Waste Management. 1976, p.95 - - -"Resource recovery
systems require large quantities of waste delivered for pro-
cessing at one site in order to achieve economies of scale . . .
plants in the 500 to 2000 ton-per-day range are likely to be
the most economical."
• Urban Systems Laboratory, M.I.T., Summer Study on the Manage-
ment of Solid Hastes. 1968, p.5 - - -"In solid waste manage-
ment there appears to be overwhelming cost advantages in being
big."
• Committee for Economic Development, More Effective Programs
for a Cleaner Environment - A Statement on National Policy.
April 1974, p.50 - —"These considerations [community size,
availability of land, expertise] lead to the suggestion that
regional agencies may be desirable for management of solid
waste collection, recovery, and disposal in many areas."
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ECONOMIES OF SCALE IN RESOURCE RECOVERY TECHNOLOGIES
There is sufficient data available for most resource recovery tech-
nologies to substantiate the statement that, in general, the cost of own-
ing and operating a resource recovery facility decreases as its size or
scale increases. In Figure 1 this is illustrated with data on three dif-
ferent technologies (bulk incineration, refuse derived fuel, and pyrolysis)
prepared for three separate projects in different areas of the country.
Net cost per ton, or the estimated disposal fee in $/ton,is plotted against
facility size, and the only conclusions that should be made from the Figure
are that net disposal fee can decrease with an increase in facility size,
and the value of the decrease varies widely for different technologies, as
well as for the same technology when applied in different projects and at
different times.
An essential statement to make about interpreting this type of data
is that it is virtually useless in predicting the cost of resource recovery
elsewhere. Differences in cost of 100% or more for basically the same
system can occur for a number of reasons:
• The equipment and construction costs can be substantially
different because of differences in the cost of land, site
preparation, or the year in which the estimate was prepared.
• The basic technology actually can be quite different in
design in terms of redundancy, design for overall avail-
ability, or extent of processing. Producing electric
power from steam, for example, requires an additional
large capital investment for a turbogenerator over the
investment required for the production and sale of the
steam itself.
• A number of cost elements are frequently left out of
estimates, including bond expenses, contingencies,
interest during construction, residue disposal, taxes,
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-171-
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etc. For line E in the Figure, for example, the inclusion
of local property taxes alone (which has been left out)
adds another $3.50 to the net disposal fee.
Projects have different degrees of risk built into the
estimated net disposal fee. The system represented by
line A in the Figure was competing against the system
represented by line C. One problem was that the expec-
ted income from the sale of RDF included in the compu-
tations for system A was highly speculative, while that
for the sale of electric power from system C was quite
firm.
The issue, again, is that it is very difficult to translate cost data,
particularly net disposal fee, from one project to another.
Also shown on Figure 1 is an example of a recent estimate for a 50 ton
per day (capacity) modular steam recovery incinerator, a so-called small
scale system (line F) now in operation in a city of approximately 30,000
people. Steam is currently being sold to a local industry. The lower point
shown ($8.00/ton) represents the net disposal fee to be paid by the city
when the quantity of steam sold at the contracted price is what it was orig-
inally planned to be when the decision was made to construct the system.
The upper point ($10.00/ton) is computed from actual experience to date.
These data are provided in the Figure to illustrate an actual case in which
a local small scale resource recovery system was chosen. Such a small scale
system can be installed in communities from 30,000 people up to 150,000-
200,000 people, provided there exists a reliable steam customer whose steam
requirements are compatible with what the system provides. This is a
critical need since without the sale of steam, the net disposal fee would
be much higher. For example, the fee for system F (in the Figure) would be
about $17.00-$20.00 per input ton without the income from the sale of steam.
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It appears at this point in time that small scale technology systems
are most likely with steam production, although under investigation now
are off-the-shelf small scale turbogenerator systems for waste heat re-
covery. It is possible that these can convert, at a small scale, solid
waste to electricity for sale at competitive prices, and result in a net
disposal fee comparable with that realized for the small scale production
and sale of steam. The importance of this, of course, is the vast expan-
sion of opportunities because of the marketability of electricity as
compared with steam, although matching electric power supply and demand
also presents formidable problems. Other small scale system opportuni-
ties are possible with materials recovery, perhaps even refuse derived
fuel preparation (RDF); however, the problems of marketing small quanti-
ties of such materials are well known.
This small scale system case is presented because it must be one of
the options to be considered by local decision makers. If it is believed
that the net disposal fee for a small scale system (or local landfill)
dedicated to the community will be approximately the same as that for a
large scale regional system, then many local officials will probably opt
for the former. This is because of the difficulties associated with re-
gionalization discussed later. In any event, if that decision is pre-
sented to them, they will certainly find it a challenging onel
As a concluding comment, it has to be recognized that the use of
small scale systems does not make regionalization unnecessary. Even
with small scale systems, communities under 25,000 population probably
will find it necessary to team up with other communities in a joint
solution. Furthermore, a concept likely to evolve is the use of a
group of small scale systems linked together as a network within a
region to form a single "system". This system would function as a
single unit; it is a regional system in disguise.
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THE TRANSPORTATION COST ISSUE
An important cost element in any resource recovery system is the cost
involved in transporting the refuse to the facility. This is particularly
important in regional systems. In the case of a central city of about
1-1/2 million people the 3000 tons per day generated represents the input
for a large scale system, probably without an increase in transportation
costs. In fact, transportation costs actually can be reduced since the
facility may be more centrally located than existing and planned landfills.
The cases we want to focus on, however, involve a smaller central city and
its suburbs, or a group of small to medium communities, within an area
spanning 50 miles or even greater, who may be able to jointly consider
their solid waste disposal problem. Analyses performed recently show that
transport of solid waste over distances of 40 miles or more can be "econom-
ically feasible", when considering three key questions relating to economic
feasibility:
(1) The benefits of the economies of scale in processing
achieved by having a larger quantity of solid waste
available for processing.
(2) The alternative cost for solid waste disposal by
whatever other option is available locally, consider-
ing also projections about increases in this cost.
(3) The manner in which the overall regional costs of
solid waste transport, processing and disposal is
to-be apportioned.
We want to illustrate in the next few figures how these questions
relate to the overall decisions that must be made about what communities
might be included in a regional system project.
Figure 2 illustrates the tradeoff of processing costs with trans-
portation cost as the size of the region increases. Note that an increase
in region size is equivalent to an increase in facility scale, which is
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-175-
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the same as an increase in number of communities which participate, and
the same as an increase in the maximum distance over which solid waste is
transported. Shown are four curves:
• Processing cost per ton which diminishes with scale. (Note
that the processing curve in reality is a set of discrete
points representing specific designs at each scale.)
• Transportation cost per ton which increases with scale.
This is shown as a step function with steps occurring at
the points where each new community enters.
t The sum of processing and transportation costs, which, in
this example, diminishes with scale up to about 1700 tons
per day (four communities) and then increases.
t An assumed standard landfill (or otherwise whatever alter-
native disposal system that is available) cost of $9.00
per ton for each community. Actually, each community
probably has- a different alternative cost based on their
landfill, incinerator, or small scale system option and
the transport cost associated with that option.
From the figure it appears that the best decision for the region Is
to scale the facility at 1700 tons/day and plan for participation by the
four closest communities; adding the fifth community causes the total
average disposal cost to increase. But what if the fifth community -- and
possibly others — are willing to pay more than the minimum disposal plus
transportation fee of about $7.00 per ton. This is possible as long as
the fee does not exceed the total cost of their alternative disposal
system, say landfill at $9.00/ton? In fact, the range between the two
figures is a "bargaining range". Under such a transportation cost shar-
ing arrangement, it actually may be better for all participating communi-
ties to enlarge the system beyond the point at which the total average
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cost is a minimum. With this concept in mind, it is possible to define
more comprehensively what "economic feasibility" really means in a
regional resource recovery system.
The concept of transportation cost sharing is not common in this
country. This is because most of the large scale systems that have been
implemented have been located in densely populated, urban areas with ample
supplies of solid waste. Therefore, it has not been required that out-
lying communities' tonnage be recruited, or when cost sharing did take
place, the arrangement has been such that each community could pay its own
transport costs. There are, however, precedents for transportation cost
sharing in Europe, specifically in Paris and London, where large scale
facilities (or even an "integrated" set of smaller facilities) require the
waste contribution of distant municipalities. These two cities have taken
the view that part of the cost of refuse transport is related to disposal
and hence, a basis for sharing costs has been established. In both cases,
the cost sharing formulae are determined by the distance involved in trans-
porting refuse from the end of the collection route to the processing facil-
ity. Reductions in disposal fees are granted to those municipalities which
have to travel more than a given distance to the processing plant.
In real practice, and when a number of independent local jurisdictions
are considering the issue, the overall question of cost sharing is possibly
even more complex than has been depicted above. Consider, for example, the
overall transportation schematic shown in Figure 3. The lowest cost total
regional design involving a number of individual communities may result in
different modes of transportation for three groups of communities:
1) Those communities (Group A) that are near the facility
and thus may proceed directly to it from the end of
their collection route. This is direct packer truck
haul.
-177-
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-178-
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2) Those larger communities (Group B) located more distant
from the facility which may be assigned a transfer sta-
tion and haul system that is dedicated to them. This
is termed single community transfer haul.
3) Those smaller communities (Group C) also located more
distant from the facility which may share in the use
of a transfer station and haul system. This is shared
community transfer haul.
Note that in this overall regional transfer system each community, from
a local government accounting standpoint, has two types of transportation
costs:
1) Those involving the existing packer (collection) trucks,
and thus are a part of the current ongoing annual ap-
propriation for refuse collection. In the regional
system these costs are probably handled in the normal
manner regardless of whether city collection or contract
collection is the current practice. In a sense, these
costs are relatively invisible.
2) New costs associated with the transfer station and
transfer haul. These are paid to the owner-operator of
the transfer-haul system, a private contractor or another
government agency. These are highly visible costs.
The result of this transportation system is that Group A communities
incur no new costs, but may incur a change in the amount of existing col-
lection costs resulting from a change in the distance to be traveled from
the end of the collection route to the facility. Group B communities have
the new transfer haul cost elements to consider, and possibly some change,
most likely a slight reduction, in collection costs because of the more
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advantageous location of their transfer station. Group C communities incur
new transfer-haul costs and possibly added collection costs to deliver solid
waste to the shared transfer station.
From all this the important question to raise is -- how should trans-
portation costs be shared and what cost elements should be considered in
the sharing arrangement? This is one of the questions that can send the
best regional plan into a tailspin. For example, these are a sample of the
problems:
t The host community may not want to share transportation
costs with outlying communities at all, and yet if it
doesn't, the plan is not economically feasible for any
community.
• Based on the particular sharing plan and the costs in-
volved, it may appear that certain communities are get-
ting preferential treatment since their new costs, which
again are highly visible, may be much lower than that
paid by other communities. In fact, the new costs could
even be negative resulting from a regional system plan
which calls for a particular community to direct haul a
much longer distance.
• Based on what it believes it is to pay for the regional
disposal service each community must decide if it is to
participate. This is done by comparing the cost of re-
gional disposal with the cost of its alternative dis-
posal options. Because of the complexity of the cost
elements involved, it is quite possible for the wrong
comparison to be made. It is also possible for local
officials to make the correct decision, but be unwill-
ing or unable to follow through because of the complex-
ity of the issue and, thus the difficulty of selling it
politically.
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But perhaps the real issue concerns who is in charge; who is really
making the decisions? The answer to that is determined by how the re-
gional thrust is organized and managed.
SOME COMMENTS ON REGIONAL ORGANIZATION
Experience has aptly demonstrated that voters are not moved by the
arguments of economies of scale, efficiency, and regionalization. Metro-
politan plans have been defeated at the polls time after time. Fragmented
metropolitan government is the result of fear of loss of power, prestige,
and responsibility, as well as a genuine concern that a regional body may
become more concerned about itself than its member units. It is also the
result, in large part, to the values and life styles of families which
have moved to the suburbs. This is a political fact of life that must be
reckoned with; the potential for regionalization, how one goes about it,
and what form is to be sought are all tied up in the political situation
unique to the area.
The simplest regional mechanism to consider for resource recovery is
the intergovernmental agreement in which one jurisdiction agrees to deliver
a service to another for a stipulated fee. The advantage to this mechanism
is that it bypasses the need for organizational changes. Another version
of this arrangement exists when a private company is to own and operate the
facility on a full service basis under a franchise arrangement with the
host or sponsoring community. Refuse delivery and disposal agreements,
with this arrangement, exist between communities and the private operator,
not the sponsoring community. Because of a lack of experience with this,
communities seem unable to distinguish between the two arrangements. But
there is an important difference indeed, since in one case a community must
perform, and in the other a private firm must perform!
Other regional arrangements are much more complex than the inter-
local agreement or private contract since they involve the creation of
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authorities, or special districts, or assigning the responsibility to an
existing regional body such as a county, Council of Government, or state.
Each regional approach involves a unique assignment of responsibili-
ties and risks. It is important to consider how the issues of siting,
contracting, and cost sharing are to be treated under each that is con-
sidered so that the arrangement is fair and equitable for all participants.
CONCLUSIONS
There is no doubt that regionalism in resource recovery is important
to progress. We certainly cannot afford to conclude that regionalization
is too difficult to consider, and thus assume that we will have some 18,000
small scale systems to replace landfills in existence today. Nor is it
useful to assume that local governments will somehow be able to decide what
is best and act accordingly. We must worry about the piecemeal approach to
resource recovery implementation in which a few communities implement pro-
jects for themselves leaving the surrounding communities without an econom-
ically viable solution. Every community in the nation must have an economic
and environmentally sound means for solid waste disposal. States must ac-
cept the responsibility to see that this occurs, but they must recognize and
cope with the issues discussed in this paper: markets, siting, waste volume,
traffic, environmental impacts, and cost apportionment among local jurisdic-
tions. This requires that states engage in rather sophisticated and detail-
ed economic planning to determine which jurisdictions should regionalize.
They must begin to understand the economic consequences in total and the
*
impact on each community of various siting and transport options . Subtitle
D of the new Resource Conservation and Recovery Act of 1976 (PL 94-580)
recognizes this need and provides guidelines for starting the planning pro-
cess.
In many cases the economic tradeoffs involved in such planning cannot be
evaluated intuitively. Computer models are available to aid in such
planning.
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In each state and in each local sftuation we eventually must come face
to face with the questions about mandatory participation in a regional pro-
ject. Should the state, or a substate regional body, require communities
to transport and deliver their waste according to a plan, or should communi-
ties' participation be optional. The answer is not at all clear. States
must have strong, well managed programs and the fiscal, institutional, and
regulatory tools needed for implementation, but communities that can suc-
cessfully solve their solid waste problem within their boundaries should be
permitted to do so.
It is more important than ever that efficient resource recovery systems
at both the large and small scale are available. For many communities re-
gionalization will not be the answer. For others a network of smaller facil-
ities will be preferred over a centralized system.
It is quite clear that there is a much larger role for private industry
in resource recovery that in other municipal service areas. The role in-
cludes operation of resource recovery facilities, as well as collection and
transport operations. Under this arrangement communities must realize that
in a regional project they may be contracting with a private firm, not an-
other community, and so the traditional fears of regionalization may not be
relevant. They should concern themselves with the wording of the contract
and not their long standing dislike and fear of the host community.
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DESIGN AND OPERATION OF THE PUROX
SYSTEM DEMONSTRATION PLANT
C.T. Moses
J.R. Rivero
Linde Division
Union Carbide Corporation
The PUROX System is a refuse processing plant which converts a low
quality, environmentally undesirable material into desirable products. Munici-
pal refuse is converted into a clean burning, low sulfur fuel gas; an inert,
glassy aggregate; scrap iron for recycling; and a wastewater stream that has
been cleaned to existing discharge standards. This conversion is accomplished
by gasifying the organic fraction of the refuse and slagging the inorganic material.
Water from the gasification is removed from the gas stream and treated to required
standards. The glassy aggregate that is produced is an inert, non-leaching
material. The ferrous material in the refuse is removed after shredding by
magnetic separation. The organic fraction is gasified to fuel gas.
This paper will present a detailed process description of the 200 ton/day
PUROX System demonstration plant in South Charleston, West Virginia. Equip-
ment description and product stream analyses are also included.
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SECTION I. INTRODUCTION
The development of the PUROX System technology began In the Union
Carbide laboratories in the late sixties with fundamental investigations into
the gasification of refuse. As a result of these theoretical studies and bench
scale demonstrations, the basic PUROX System technology, the gasification of
refuse in a vertical shaft furnace utilizing pure oxygen, was developed. The
initial development of the concept was carried out in a 5 ton per day pilot furnace
which was built and operated in the Union Carbide Technical Center in
Tarrytown, New York. A history of the early development of the process and a
general description of the operation of the pilot unit were presented in a paper
given by Dr. I. E. Anderson, the inventor of the process, at the 1974 National
Incinerator Conference. The successful operation of the unit resulted in the
conceptual design and economic evaluation of commercial scale PUROX System
plants. The favorable results of these initial evaluations led to the decision
by Union Carbide to finance and construct a 200 ton per day full scale prototype
plant in South Charleston, West Virginia. Operation of the demonstration plant
began in April, 1974. Initial operation of this plant was described in a paper
(21
presented in September, 1975 at the 80th National Meeting of the A.I.Ch.E.
A schematic drawing showing the basic operation of the shaft furnace is
presented in Figure 1. Refuse is contacted countercurrently with hot gas
from the combustion reaction occurring in the hearth. The hot gas transfers heat
to the refuse , and the gas is cooled in the process. As the solids
proceed down the shaft they are heated by contacting progressively hotter gas.
Initially, as drying of the solid occurs, free water in the refuse is vaporized.
As temperatures in the solid continue to rise, gasification of the organic portion
of the refuse begins to occur by pyrolytic reactions. These reactions convert
from 50 to 60% of the original weight of the refuse to gaseous products. The
pyrolytic residue, which consists of non-volatilizable carbonaceous material,
and the inorganic portion of the refuse, is consumed in the hearth in a combustion
reaction with pure oxygen. The oxygen reacts with the carbonaceous fraction of
the char to liberate the energy required to melt the inorganic materials into a
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fluid slag product. The hot gases from this combustion reaction also provide
the energy to carry out the drying and pyrolysis reactions in the upper shaft.
The details of the pyrolytic reactions and the rates at which these
reactions proceed are extremely complex. However, some msight into the
fundamental effects occurring in the converter can be obtained by considering
the gasification process to be operating in a heat controlled manner. The
drying, slag formation, and generally speaking, the pyrolysis reactions all
require that energy be supplied to carry them out. This energy must be supplied
by the char-oxygen reactions in the hearth. If the organic portion of the char
is taken to be essentially carbon, the char can react with oxygen in either of
two basic reactions which liberate energy:
Reaction Heat of Combustion
(1) C + 1/2 02 -» CO 3,950 Btu/lb carbon 2,960 Btu/lb oxygen
(2) C + 02 -»• C02 14,090 Btu/lb carbon 5,280 Btu/lb oxygen
If all the energy required for gasification and slagging could be supplied via
reaction (1), the energy yield of fuel gas per unit of refuse processed would be
maximum. In practice, using typical municipal refuse with a nominal heating
value of 5,000 Btu/lb and a carbon, hydrogen, oxygen composition approximately
that of cellulose, about 1/4 of the incoming carbon is found in the product gas
as C02. The conversion of the carbon to CO will not provide sufficient
energy for the gasification and slagging requirements. There are other
reactions which can affect the C02 level in the product gas; however, the carbon-
oxygen reactions are the primary source of energy for the conversion process. It
has been shown that the oxygen required to convert refuse into gas and slag is
about 20% by weight of the refuse ot composition similar to that described below.
SECTION II. PROCESS DESCRIPTION - 200 Ton Per Day Demonstration Plant
The PUROX System consists of the following components: a front-end
refuse receiving and preparation system, a refuse gasifying system, an offgas
cleaning system, and auxiliary systems including an oxygen generating plant,
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a wastewater treatment system, and a product gas compression and distribution
system. Since one of the primary functions of the PUROX System plant might be
to provide a continuous supply of fuel gas to a municipal or industrial user, 24
hour per day, 7 day per week plant operation is required. Figure 2 presents a
process view of the 200 ton per day demonstration plant in South Charleston,
West Virginia.
The processing of refuse in the PUROX System plant begins in the refuse
receiving and storage building. The purpose of this building is to provide one
day's inventory of refuse at the system's rated capacity of 200 tons per day.
This storage is provided by a building 80 feet by 70 feet with a 12 foot concrete
wall on three sides to provide protection for the structure during the refuse piling
operation. Refuse is brought to the plant in conventional packer trucks, dis-
charged directly onto the floor of the building, and piled against the concrete
walls using a Caterpillar model 950 front loader.
The front loader is used to carry refuse into the system for further
processing and to manage the refuse inventory. The front loader loads about
one ton of material in its bucket and conveys it to the scale for weighing and
discharge into the processing system (see Figure 2 for PUROX System Schematic).
The scale used for weighing the front loader and its load is a Toledo model 820
full load cell platform scale with a model 8130 digital indicator. It can weigh
in a range from 0 to 40,000 pounds in 20 pound increments. The refuse entering
the system has a composition similar to that indicated in Tables I and II showing
component and ultimate analyses for typical municipal refuse.
After weighing, the refuse Is dumped onto a conveyor which transports
the material to the shredder. The conveyor is a three foot wide apron conveyor
installed at a 45° angle with respect to grade. The shredder is a Heil (Tollemache)
vertical shaft hammermill equipped with a 200 hp electric motor. It is rated at
15 tons per hour shredding capacity. Significant overcapacity is required in the
shredder to allow a reserve for mechanical problems in the feed system as well
as routine maintenance. Since the PUROX System operation runs 24 hours per day,
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seven days per week, hammers can be run at most a few days before resurfacing
is required. Wear surfaces on the interior of the shredder must also be built up
periodically. The net effect of these requirements is that in the South Charleston
PUROX System operation 2-3 hours per day are required for maintenance on the
shredder.
The overall control of the feed system rests with the feed system operator
who takes action in response to the requirement for fresh material by the converter.
In addition, there are several automatic control circuits built into the system to
prevent improper operation. One of these control circuits provides overload pro-
tection for the shredder by stopping the feed conveyor whenever the amperage
drawn by the shredder motor reaches a set level. This allows the shredder to
continue grinding its charge without increasing its load by adding new material.
Once the material has been processed sufficiently to allow the load on the
shredder to drop below the overload condition, operation of the feed conveyor
resumes as control is returned to the operator.
In addition to the overload circuit described above, the shredder
is also equipped with an interlocked control circuit. This control circuit
requires that both the blower cooling the shredder drive motor and the
discharge belt conveyor for carrying material away from the shredder be
operating before the shredder can be run. This circuit ensures that the
shredder will not be choked by discharging material or that its drive motor
will not overheat. If either of these conditions occur, the shredder is
automatically shut down. The shredder is also equipped with a restart
limiting timer which prevents restarting the motor more than once per hour
to protect it from overheating.
The discharge conveyor from the shredder is a high-speed, rubber-
belted device which transports material from the shredder to the feed conveyor
for the converter. As the shredded refuse travels along the belt conveyer, it
passes through a magnetic separator which removes ferrous material. The
magnet picks up pieces of iron in the shredded refuse stream and discharges
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it onto a second belt conveyor which runs perpendicular to the shredder dis-
charge conveyor. The shredded, magnetically separated refuse has a composition
similar to that given in Table III.
The shredded, ferrous-free refuse is dropped from the belt discharge
conveyor onto a second apron conveyor for transport to the feeder. The feeder
acts as an interface between the front-end refuse processing systems and the
converter where the refuse is consumed. The mission of the feeder is two-fold.
It introduces the refuse into the converter and provides a gas tight seal for the
system.
Once the refuse is in the converter, it is contacted countercurrently
with hot gas produced from combustion in the hearth. As the refuse passes
down the shaft and is contacted with hotter and hotter gas, it undergoes
several reactions. First, near the top of the converter, free moisture is
driven off. As the temperature of the gas at the surface of the refuse increases,
pyrolysis of the refuse begins to occur. In these pyrolysis reactions, the
cellulosic material in refuse is broken down into smaller molecular fragments
which contribute to the final gas composition. At the same time, hot gas
from the combustion of char in the hearth undergoes shift and carbonization
reactions which reduce the amount of C02 in the gas while forming CO and H2 .
The complex mixture of gases and refuse undergoes a variety of reactions
leading to the final offgas composition as indicated in Table IV. The offgas
typically exits the converter at 200 to 600°F with a wet bulb temperature of
170-180°F.
The hearth operation is carried out at a temperature of about 3,000°F
in order to slag the inorganic portion of the refuse and combust the char residue
of pyrolysis. To maintain this condition requires refractory linings with service
temperatures well in excess of 3,000°F and a high resistance to slag corrosion.
Extensive operating experience has shown that standard refractory and water
cooling on the exterior shell is sufficient to form and maintain a protective
slag "skull" on the inside refractory surfaces. The molten slag pours from the
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hearth into a water quench tank. After quenching, the slag is withdrawn from
the bottom of the quench tank using a drag conveyor which deposits the slag in
a dumpster for removal. The composition of the slag stream leaving the con-
verter is given in Table V. As can be seen from Table V, the slag residue has
a bulk composition very similar to that of soda-lime or bottle glass which is
its main constituent. Most of the inorganic materials in the refuse become
bound in the glassy slag. Leaching tests have been conducted on the slag
using both acidic and pH 7 water. The results of these tests indicate that the
trace metal contaminants do not leach from the slag sufficiently to create an
environmental hazard. Table VI presents a comparison of leachate water
quality obtained from 6-day percolation tests in a bed of pure PUROX System
slag with U.S. Public Health Service recommended drinking water standards.
These results show that the slag leachate compares favorably with drinking
water quality indicating that potentially leachable materials are well bound
in the glassy slag. Table VII presents a comparison among 6-day leachate
samples from a pure slag sample and two different blends of slag and soil
that might be encountered in a landfilling operation. The changes in leachate
quality can essentially be attributed to the soil components themselves.
While the inorganic fraction of the refuse exits as a molten stream
from the converter, the organic fraction is converted into a fuel gas which
is further processed in a gas cleaning system. Particulate matter is collected
using a water scrubbing system followed by electrostatic precipitation. The
material collected in both of these units is recycled to the converter for gasi-
fication or slagging. After gas cleaning, the offgas is cooled to 100T in a
condenser to remove wastewater prior to the end use of the gas. Following
this step, the gas in the demonstration plant is simply flared as in Figure 2
since there is no user available. In a commercial plant, a gas ccmpression
and distribution system would handle the gas.
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SECTION III. SUMMARY OF OPERATIONS
The 200 ton per day PUROX System demonstration plant has undergone
extensive testing since construction was completed in April, 1974. While
it initially operated on as-received refuse, in late 1974, the plant was modified
by the installation of shredding and magnetic separation equipment.
More than 10,000 tons of refuse have been successfully processed through
the facility. The main purpose of the plant was to develop and optimize the cost
and performance of a commercial-scale system. Most of the test runs were of
relatively short duration (about 1 to 3 weeks). These runs provided data to
evaluate specific modifications or operating conditions aimed at optimization
of the commercial process. Additionally, an extended run was conducted for
the purpose of establishing system reliability. During the three-month-long
run, about 7,000 tons of refuse were processed, with a demonstration system
reliability of about 93%.
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Table I: Component Analysis of Refuse
Range (Wt.
Wet Basis
Paper
Food
Yard
Wood
Plastic
Textile
Rubber & Leather
Glass
Ferrous Metal
Nonferrous Metal
Dirt and Ash
Wt. %
38
20
13
3
1
1
1
11
7
1
4
(Moisture included in above) 26%
25-60
10-30
10-20
2-4
0.5-2
0.5-4
0.5-3
5-25
5-9
0.2-1
1-6
100%
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Table II: Ultimate Analysis of As-Received Refuse
Component
H2°
C
H
O
N
S
Cl
Metal
Glass
Ash
Weight %
26.0
25.9
3.6
19.9
0.47
0.10
0.13
8.0
11.0
4.9
100.0
Higher Heating Value
4992 Btu/lb.
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Table III: Ultimate Analysis of Shredded, Magnetically Separated Refuse*
Component Weight %
H20 27.9
C 27.7
H 3.8
O 21.2
N 0.5
S 0.11
Cl 0.14
Metal 1.7
Glass 11.8
Ash 5.2
100.0
Higher Heating Value = 5140 Btu/lb
* Based on
a) 90% removal of magnetic metal
b) 10% non-metal in removed stream
c) 15% removal of non-magnetic metal due to attachment
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Table IV: SUMMARY OF PUROX SYSTEM
FUEL
GAS ANALYSIS at 60 «F, 1
H2
CO
co2
CH.
4
C H
2 2
C,H.
2 4
C0H_
2 6
HH.
3 6
C3H8
C
4
C5
C H
6 6
C7H8
V
N2
Ar
°2
H2S
CH OH
ORGANIC VAPORS*
H20
GAS CHARACTERISTICS
C
atm. TYPICAL
23.6
38.3
23.6
5.9
0.7
2.06
0.3
0.3
0.2
0.5
0.4
0.3
0.1
0.2
1.0
0.5
0.1
0.05
0.1
0.15
1.64
& VOLUME
RANGE
21-23
29-42
20-34
4-7
0.2-1.5
1-3
0.1-0.5
0.02-0.7
0.1-0.6
0.1-0.8
0.1-0.6
0.1-0.6
0.05-0.15
0.1-0.7
0-1. S
0-0.5
0-0.2
.02-. 06
0.05-0.15
0.1-0.4
1-2
*Hlgher alcohols, aldehydes, ketones, organic acids
-195-
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TABLE V
PUROX SYSTEM RESIDUE ANALYSES
Major Components
Silicon
Aluminum
Calcium
Sodium
Iron
Magnesium
Potassium
Phosphorous
Titanium
Manganese
Trace Compounds -
Barium
Copper
Zirconium
Strontium
Chromium
Lead
Tin
Nickel
Zinc
Vanadium
Cobalt
Silver
Molybdenum
Antimony
Berrylium
Sulfur
Chlorine
- Weight %, Expressed as Oxide
59.7 57-62
10.5 9-13
10.3 9-12
8.0 7-10
6.2 1-8
2.2 1-4
1.0
0.8
0.6
0.3
99.6
ppm
1000-3000
500-3000
300-1000
200-400
100-400
50-300
50-300
50-250
50-250
25-80
15-40
5-30
10
3-10
5
1000-3000
5000 - 10,000
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TABLE VI
WATER QUALITY OF PUROX SYSTEM SIAG LEACHATE
Pure Slag
T.par.hatp
Material
Total Acid
Total Alka.
BOD
COD
Chloride
Cyanide
Fluoride
Aluminum
Arsenic
Barium
Cadmium
Calcium
Chromium
Copper
Iron
Lead
Selenium
Silver
Sodium
Zinc
Nitrate
Diss. Sol.
Sulfate
Sulfide
Manganese
(ppm)
10
20
0
5
12
0
0
<0
<0
<0
<0
2
<0
<0
0
0
<0
<0
1
<0
<0
27
1
<0
0
.7
.0
.93
.0
.0
.001
.03
.8
.01
.1
.001
.1
.01
.1
.33
.07
.01
.02
.10
.05
.2
.0
.3
.02
.02
U.S.P.H.S.
Limit
0
1
0
1
0
0
0
0
0
.2
.6-3.4*
.05
.0
.01
.05
.05
.01
.05
U.S.P.H.S.
Re comme nde d
Level
250
0
0
0
1
0
5
45
250
0
.01
.8-1.7
.01
.0
.3
.0
.0
.05
*Fluoride concentration is temperature dependent
-197-
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TABL2VII
Material
Total Acid
Total Alka
BOD
COD
Chloride
Cyanide
Fluoride
Aluminum
Arsenic
Barium
Cadmium
Calcium
Chromium
Copper
Iron
Lead
Selenium
Silver
Sodium
Zinc
Nitrate
Diss. Sol.
Sulfate
Sulfide
Manganese
SLAG + SOIL
Pure Slag
Leachate
(ppm)
10.7
20.0
0.93
5.0
12.0
0.001
0.03
0.08
0.01
0.01
0.001
2.1
0.01
0.1
0.33
0.07
0.01
0.02
1.10
0.05
0.2
27.0
1.3
0.02
0.02
INTERACTIONS
Slag Cont.
Silt + Slag
System
5.6
8.6
0.4
12.0
8.3
0.001
0.01
3.9
0.01
0.13
0.001
1.6
0.01
0.1
7.3
0.05
0.01
0.02
2.6
0.17
0.2
13.0
10.0
0.02
0.14
Slag Cont.
Silt + Slag
System
16.0
7.9
0
9
3.6
0.001
0.04
3.8
0.01
0.1
0.001
3.0
0.01
0.1
7.2
0.05
0.01
0.02
1.5
0.05
0.23
26.7
2.7
0.02
0.02
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REFERENCES
1. Anderson, I.E., Proceedings of the 1974 National
ASME Conference, Incinerator Division, p. 337,
April, 1974.
2. Fisher, T.F., Kasbohm, M.L., and Rivero, J.R.,
A.I.Ch.E. 80th National Meeting, September, 1975.
3. Water Quality Criteria, 2nd Ed., June 1, 1974,
State of California, p. 89.
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RESCO - FIRST YEAR OF OPERATIONS
John H. Kehoe, Jr.
Vice President - General Manager
Energy Systems Division
Wheelabrator-Frye, Inc.
Our RESCO facility in Saugus, Massachusetts, is a 1200 tori
per day waste disposal system and power plant. Wo placed it into
operation in September, 1975, and began delivering steam to
General Electric on November 15, 1975.
Our first year of operation has been devoted to the sequential
start-up and shakedown of the two 750 ton per day boilers. During
this start-up period we have processed in excess of 250,000 tons
of refuse, produced over one billion pounds of steam, and recovered
an estimated 16,000 tons of ferrous metals. We are currently
processing refuse at an average rate of 800 tons per day and expect
to reach our capacity early next year.
RESCO has proven to be an environmentally sound operation.
The plant, operating at full capacity, has surpassed the Massa-
chusetts air emission code of .05 grains per SCF, corrected to
12% coo' Chemical and leachate analysis studies have shown that
the plant's residue is inert and will not effect the surroundim,
marsh and shellfish environment. The plant has operated completely
free of odor. Noise recordings at the property lines are maintained
at less than 50 decibels.
Research and development programs conducted since the incep-
tion of operations have provided us with additional encouragement
that our total recycling goal is achievable. There are indications
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that with further processing the ferrous metals can be upgraded
to a No. 1 quality. The aluminum and non-ferrous metal content
has been estimated between -5o to .7% concentration, and the tech-
nical feasibility of recovering a marketable product has been
demonstrated. The aggregate residue has been found acceptable
for product applications, such as landfill cover, road base and
embankment fill, and for use in bituminous concrete and concrete
blocks. Studies on its use in portland cement are encouraging
but as yet are not completed.
At the present time, RESCO residue is being stored adjacent
to the plant site awaiting completion of studies to determine the
economic feasibility of recoverying non-ferrous metal and receipt
i-
of state approvals for its sale as a fill or aggregate material.
The land requirements for residue storage are approximately 3%
of that required to landfill the raw refuse from which it was
derived.
BACKGROUND
Before discussing the RESCO operations in detail, I would
like to give you a brief understanding of the project organiza-
tion, the background experience upon which it is based, its
performance requirements, and structure of our energy and waste
disposal contracts.
RESCO is operated as a joint venture between Wheelabrator-
Frye and M. DeMatteo Construction Company and organized as "Refuse
Energy Systems Company." The joint venture made a substantial
equity contribution to the facility and arranged industrial revenue
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bond financing for the debt portion of its investment. No public
funds are committed or obligated to the project.
System design and construction management were carried out
by The Rust Engineering Company, a wholly owned subsidiary of Whoelabrator
Frye, and construction was undertaken by M. DcMntteo Construction Company.
The plant design concept is based upon Wheelabrator's exclu-
sive U.S. license with Von Roll, Limited, of Zurich, Switzerland.
It is the most advanced version of the over 120 Von Roll refuse-to-ener.gy
plants operating or under construction in Europe, Australia,
Japan, ^nd Canada. RESCO is designed to meet more severe
environmental requirements and a number of specialized demands
imposed by site conditions and unusual requirements for reliability
and continuity of refuse acceptance and steam production. It'also
employs several advanced design features to enhance cost effective
and reliable performance al high sLe^m Li^inpt-jLaLuieb.
Minimizing operating costs over the life of the plant were
considered essential to provide protection against inflation.
The approximate $40 million capital cost for the plant recognizes
these requirements and special conditions. It includes all costs
for land, maintenance, shops, roads, weighing stations, vehicles,
spare parts, utilities, and a one-half mile pipeline and bridge
system extending across the Saugus River to the General Electric
Company for steam delivery, condensatc return, and electric power.
RESCO1s basic requirements are to accept an average of 1200
tons per day of municipal and commercial refuse and deliver steam
to General Electric at 625 psig and 825°F. The plant is operated
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24 hours a day, 7 days a week. Peak steam delivery is 350,000# per
hour and not less than 65,000)' per hour. A minimum of 2.0 billion
pounds per year of steam will be delivered to the customer. The primary
uses of the steam are for electric power production, processing,
and testing operations.
Through close cooperation with General Electric, a long term
contract for the sale of steam to their Lynn River Works Plant was
consummated. In addition, a combination of long and short term
contracts have been completed with eleven surrounding communities
and two districts of Boston for waste disposal services.
Steam charges to General Electric are somewhat lower than their
cost to produce steam from oil and will escalate or de-escalate with
variations in their oil prices. The communities are charged a base
disposal fee for each delivered ton of waste. This fee is adjusted
annually at approximately 50 percent of the rate of change in a local
labor rate index. Excessive increases in operating costs or cKlc'c^
capital costs are absorbed by RESCO.
OPERATING EXPERIENCE
The success achieved in our first year of operations could
not have been accomplished without the utilization of proven
experience and technology in the design, construction and start-up
phases of this project. Lvery basic subsystem has proven
to be operationally sound and capable of meeting its projected
life cycle. This is not to say that operations have been
trouble free but reaffirms our belief that the utilization of a
proven technology and system design is essential to avoid the
risk of excessive overruns in capital and operating expenses.
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Priorities
Our first and primary r'esponsibility at RESCO is to provide an
environmentally sound and reliable disposal service to the communities
we serve. To date, not one truck has been diverted to an alternate
disposal site.
Secondly, the plant's steam production will permanently
replace approximately 40% of General Electric's required steam
generating capacity. G.E. employs over 13,000 people at the Lynn
Plant, and continuous steam flow from RESCO will be essential
to insure normal operations. Each refuse boiler and the two
back-up package boilers have achieved rated steam capacity and
steam quality specifications under full load operating condition!;.
Final tuning and control modifications should be completed by
year end, and G.E.'s transition to full dependency on RESCO steam
is expected to go smoothly.
These services must be provided in an environmentally sound
manner. As mentioned earlier, RESCO has met and surpassed the
Commonwealth of Massachusetts and Federal environmetnal regulations.
Finally, there is a strong commitment to the separation and
recovery of material resources from the system's post-combustive
residue. The original plant design incorporated a capability to
physically separate ferrous metals. At the time the plant was
being designed, through construction and after the first year of
operations, we have seen no economically.viable recovery technology
developed for the aluminmu, non-ferrous metals, and glass produce:d
by the system. We have seen the technical feasibility of recovering
and upgrading these material resources however, and are presently
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evaluating the economics of recovery system designs and trying to develop
firm market commitments. Based upon our present knowledge, we do not
anticipate these products generating more than S3 per ton of refuse
in net revenues unless there are significant increases and stabilization
in their market values.
PLANT DESCRIPTION
The following discussion combines our specific operating
experiences with a physical description of the operating areas
of the facility.
Refuse Receiving and Handling Area
This area of the plant incorporates the weighing station at the
entrance to the plant, the queuing and receiving areas for the trucks,
the storage pit for the refuse, the refuse mixing and furnace
loading operations, and the shredder plant. All refuse trucks entering
and leaving the plant must cross the semi-automatic scales. Tare
weight cards are maintained on each municipal truck to avoid delays.
The reception area allows adequate turnaround and waiting space for
several trucks. Sixteen outloading bays are provided for approximately
250 trucks per day. The average turnaround time for each truck has
been between five and seven minutes. The traffic flow patterns
designed into the plant operations have proven to be highly efficient.
The refuse storage pit is 35' wide, 95' high, and 200' long and
has a capacity to hold over 6,000 tons of refuse. The refuse mi' -
ing and loading is handled by two overhead cranes which have a refuse
lifting capacity of approximately 3 tons per load. Initially, the
heavy duty placed upon the cranes caused considerable cable and brake
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wear. Changes in the operating control system enabled us to correct
the problem and achieve acceptable performance.
The shredder is a 50 ton per hour, 1000 horsepower hammermill
installation. Our original intent was to shred bulky metals, such as.
refrigerators, stoves, water tanks, etc., and large combustible itenis
such as sofas, tree trunks, etc. The shredder operation has been
reduced to one day per month and only for bulky combustibles that would
normally require more than one hour retention time in the furnace for
complete energy conversion. The furnace opening is 22' long and 4' wide
and has proven to be sufficiently large to process all of the bulky metals
received without preprocessing.
This inherent flexibility in the design has enabled us to eliminate
the costly expense of operating and maintaining the shredder. Based
upon the variation in bulky material delivered to RESCO over the last
year, we are becoming convinced that future plants can be built without
the need of a shredder.
REFUSE COMBUSTION AREA
Refuse received from the fecdhoppers is burned on a Whcclabrator/
Von Roll reciprocating qrate system without the use of auxiliary fuel.
In addition to the grates, this area also incorporates the auxiliary
equipment which automatically controls the grate speeds and air distri-
bution. The grate system consists of three independently controlled
grates separated by steps over which refuse tumbles to provide complete
combustion. The first or feed grate controls the rate at which refuse
is fed. The second or combustion grate is maintained at a speed which
will insure an estimated 901 of the combustion. The last grate is the
burnout grate which is controlled to insure the completion of the
combustion process and partial cooling of the inert residue.
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Combustion gas temperatures arc maintained in the range of 1600 -
1800T, which is sufficiently high to dcstoy odors. Combustion and
overfire air systems are integrated with individual grate speed controls
to provide uniform and stable energy production from changing refuse
compositions while insuring complete burnout.
Some recent design improvement incorporated at RESCO permit the
direct combustion of unpreprocessed municipal refuse at the higher
steam temperatures needed to achieve efficient electric generation.
They include air jets positioned to introduce air along the side walls
and under the stepped grate systems . The air system provides protection
against corrosion that might occur in the presence of reducing atmospheres,
limit slag buildup on the side walls, and add to the gas turbulence needed
to minimize hot spots on the furnace walls and boiler tubes.
As is the case in any major plant start-up we encountered problems.
However, only two start-up problems were cause for concern. These
problems included a failure in the sliding grate shoe support shoes caused
by a departure in the specified metallurgy and unevenncss in the
hydraulic grate drives. Remedial actions were identified, modifications
made, the problems disappeared.
STEAM PRODUCTION (BOILER)AREA
The steam production area incorporates the most advanced design
in refuse boilers. This design has evolved from over 20 years and
4 million hours of operating experience with the Von Roll technology.
Also included ij the radiation or water wall section of the boiler which
is located in the furance area and is of a conventional design.
The hot flue gases from the furnace pass through three convection
sections which transfer the heat to produce superheated steam. These
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sections arc designated as the economizer, evaporator, and superheater.
Vertical pendant hung boiler tubes are constructed and specially
designed with a mechanical rapping mechanism.
The convection passes include economizer, evaporator and super-
heater sections. Each section is constructed with pendant boiler tubes
which are equipped with specially designed boiler tube rapping mechanisms
to remove dust and scale from the tube surfaces. This unique cleaning
system enables the tubes to retain the protective oxide layer that is
normally removed when soot blower or steel shot is used for cleaning.
Recent European experience has demonstrated the effectiveness of this
cleaning system by eliminating shutdowns for tube cleaning.
An automatic temperature regulatory system provides uniform steam
flow at full capacity without exceeding temperature ]imits as tho
heat contact of refuse varies. These and other advancements combine
to promote reliability and provide boiler availability percentages
in the same range as utility boilers fired by fossil fuel.
The problems encountered in this area of the plant are corrosion
of tube metal wastage. Fortunately, from our experience with Von Rol I 's
plants in Europe, we have been fully aware of the potential for corrc •-1 •
and incorporated a boiler specifically designed for the combustion of
refuse. With the knowledge we have gained about solid waste and our
anticipated modificaitons, we believe we have the fix.
Before going on, there are two points I'd like to make:
1) If you are going to burn refuse and produce steam at high pressure:
and temperatures you are going to have corrosion. You arc not going to
control it by removing PVC's. There are a myriad of other elements in
municipal waste that contribute to corrosion.
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• 2 ) Conventional boilers arc designed to burn homogeneous conventional
fuels. Refuse is not a homogeneous fuel nor do you control its chemical
composition by preprocessing it to remove non-combustibles.
A few faulty welds in the pressurized section of the boilers, insuf-
ficient shielding, a need for improved metallurgy in a portion of the
superheater exposed to direct radiation, and a failure of a steam
temperature controller represent the extent of difficulties encountered.
With few exceptions, all modifications have been completed.
AIR POLLUTION CONTROL AREA
Air emissions from the plant are controlled by Wheelabrator/Lurgi
electrostatic precipitators, and emissions emitted to the atmosphere
through a 178 foot masonry stack. The precipitators are operating at
approximately 99 percent efficiency. This has permitted the system
to surpass the local particulate emission requirements of .05 grcins per
standard cubic foot, corrected to 12% CO,,. Each precipitator handles
240,000 cuff/min. of flue gas at 425°F. We have experienced no operating
problems in this area.
MATERIAL SEPARATION AND RECOVERY AREA
This area begins with the collection of fly ash from boiler
and precipitator hoppers, riddlings and grate siftings, and residue
from the burnout grate. These residues are presently transported
to a common and redundant water quenching and washing system. The
system is continuously neutralized to a pH of approximately 7. In
addition to cooling the residue, it removes soluble salts which could
be an environmental nuisance. As the residue settles to the bottom of
the quenching system, it is removed by a drag chain conveyor which trans-
ports it to the material recovery building.
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The material recovery system consists of a rotary trommel screen
with two inch holes, magnetic separators, and appropriate conveying
and collection systems.
The plus two inch material is classified as the bulky metal residue
and has a ferrous metal content of approximately 60%. The minus two
inch material falling through the screen is conveyed to a permanent
magnet separator which collects the fine ferrous metals. The ferrous
metal recovered represents approximately 7.5% by weight of the incoming
refuse, and the fine ferrous fraction is estimated to be 20% of the total
ferrous product recovered. Both fractions are presently sold to a local
secondary market under short term contracts.
The remaining residue is aggregate material which contains the
glass and approximately a 2% concentration other non-ferrous me'tals.
Chemical and leachate analysis studies show that the aggregate is inert
and acceptable as a fill material.
Research and development studies designed to analyze the
feasibility of upgrading the ferrous metals, of recovering a marketable
aluminum and non-ferrous metal product, and developing product applications
for the aggregate are all encouraging.
Utilizing Wheelabrator foundries, we have made pig iron from several
samples of the recovered ferrous metals. Working closely with the major
steel companies, we have made comparative chemical and metallurgical
analysis. The results show, that the copper content is too high for No. 1
grade applications. Further studies have shown that copper can be
separated with shredding and further magnetic separation. A program is
underway to determine economic benefits that can be derived from further
processing to remove the copper.
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Through size classification of the aggregate, we have produced
a 60%- aluminum and non-ferrous product which is salable. In addition,
we are presently analyzing the small quantity of melted aluminum
product collected under the grates. Although results to date look
favorable for aluminum recovery, there is the possibility that the
final recovery system requirements may make it economically impractical.
The aggregate which comprises approximately 50% to 60% of the
residue from the plant has been successfully used in bituminous
concrete, decorative concrete for floorings and walls, and concrete block
applications. It has also been proven acceptable as a road base and
embankment fill material. Research studies are continuing to expand
its product applications as a cement supplement and light weight
aggregate for construction.
COMMUNITY EXPERIENCES
This status report on RESCO would not be complete without briefly
summarizing some of the benefits, other than waste disposal, that the
communities have received from participation in the project.
The following benefits have resulted in a reduction of collection
expenses which in effect have reduced their overall budgets for waste
collection and disposal.
Because no presorting or separation is required at RESCO,
the communities have been able to combine garbage, rubbish,
and bulky trash collections into a single pickup operation.
RESCO routinely supplies to the communities scale weights .
on each truck delivery. With this data the communities have
been able to reduce the number of collection routes and optimize
loading of collection vehicles.
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Cost benefits have been derived by reduction of vehicular
requirements and shifting of manpower to other municipal departments.
CONCLUSION
The success we have achieved during the first year of operations
at RESCO demonstrates, on a commercial scale, that refuse fired boilers
of this type can provide an environmentally sound solution to the
municipal waste disposal problems facing the urban areas of this country.
In addition, it demonstrates that private enterprise can provide this
solution without tapping municipal, state or federal financial or
taxing resources.
However, it is only a partial solution. There still is and will
be for many years to come a need for sanitary landfill for those wastes
generated that cannot be handled by resource recovery systems of all
kinds.
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FEATURED ADDRESS
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FEATURED PRESENTATION
FIFTH NATIONAL CONGRESS ON WASTE MANAGEMENT TECHNOLOGY
AND
RESOURCE AND ENERGY RECOVERY
DALLAS, TEXAS - DECEMBER 1976
PETER VARDY
VICE PRESIDENT-ENVIRONMENTAL
MANAGEMENT & TECHNICAL SERVICES
WASTE MANAGEMENT, INC.
Welcome to the Fifth National Congress on Waste Management Technology and
Resource and Energy Recovery. This is also the third Waste Management Technology
Conference co-sponsored by NSWMA's Institute of Waste Technology.
As most of you will recall, the Institute of Waste Technology was established by
NSWMA's Board of Directors in the summer of 1974 in response to the Association's
expanding scope of activities and technical programs. The main purpose of the
Institute is to provide a national forum for technology assessment and planning for the
entire waste mamgement field.
Through its three major member committees and two councils, the Institute has,
during the past two and one-half years, taken a very active role in assisting government,
industry, members of NSWMA and its Legislative Planning Committee with technical
and planning expertise. The Chemical Waste, National Sanitary Landfill and Industry
Resource Recovery Committees have reviewed and provided valuable input into
legislation, regulations and technical information generated by Congress, the U.S.
Environmental Protection Agency, and state legislatures and regulatory agencies.
Through the varied activities of its committees, the Institute has also promoted the
development of new, technically reliable, economical and safe waste processing,
resource recovery and disposal systems.
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Since my appointment as Chairman of the Institute in 1974, I have had the
privilege of working with many of you in Government, industry and the consulting
professions, and the opportunity to observe some rather profound changes in our
industry during this relatively short period of time.
Permit me, at this time, to make a few brief and personal observations on
some of this industry's accomplishments and failures during the past two and
one-half years.
During 1974, I said that there was a general feeling of euphoria concerning
developn _nt of resource recovery in this country and the great economic and
technical promise which it held for the solid waste management industry. A
number of EPA-funded resource recovery demonstration projects were receiving
wide publicity and the construction of full-scale facilities was strongly en-
couraged by 'various government agencies. This climate of extreme enthusiasm
generated immediate demands by a rather naive and misinformed public to eliminate
land as an acceptable sink for the disposal of residues and achieve, almost over-
night, total recovery from waste of material and energy resources. Many
within and outside the solid waste industry were thus led to believe that
full-scale resource recovery, representing a new multi-billion dollor market
in equipment, facilities and services, was just around the corner. In retro-
spect, of course, we recognize that such expectations were premature.
By fall 1275, during our Fourth National Congress in Atlanta, the realities of
life have.become apparent and depression set in. The falacies of rapid scale-up;
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the difficulties encountered in obtaining long-term financing on the strength of short-term,
fluctuating markets for recovered resources; serious difficulties encountered in the effective
control of waste; and the real impact on disposal fees of the highly capital intensive
resource recovery systems were reported by all who tried their hand at this new area of
opportunity.
This year 1 sense that you will find a very healthy spirit predominating at this
conference, a spirit which will be characterized by pragmatism and cautious optimism.
You will hear reports of some successes with full-scale facilities (information essential
to rational assessment of resource recovery alternatives), of communities moving into
the area of resource recovery cautiously and realistically, and of the readiness of the
financial community to fund such projects provided they are approached in a business-
like and responsible manner.
The Institute's Industry Resource Recovery Committee, which has in its membership
eight of the country's leading systems and service companies in the solid waste management
field, has b?en very active in evaluating and disseminating information on all aspects
of resource recovery systems, including waste processing technology, financing, markets
for materials and energy products and peripheral delivery and disposal system. By
conducting roundtable seminars for interested communities, assessing and disseminating
information on resource recovery projects around the country, and by providing continuing
technical assistance to government and industry in the promulgation of resource recovery
procurement and other implementation guidelines, the Committee is playing an important
and active role in promoting the advancement of responsible and effective resource
recovery in this country.
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The Chemical Waste Committee, in anticipation of overdue hazardous waste
legislation, regulation and enforcement has been actively engaged in the development
of a comprehensive Legislative Guide for a Statewide Hazardous Waste Management
Program. This guide, incidentally, provides considerable background material and
outlines the industry's version of the guidelines which EPA must promulgate by Spring
1978 under the newly enacted P.L. 94-580. The Committee has also developed a model
manifest to complement the legislative guide and has been working closely with the
U.S. EPA Hazardous Wastes Management Division in reviewing and commenting on
the various studies undertaken by that division. During the coming year, the Committee
will be working on such projects as chemical landfill standards, monitoring requirements
for land disposal sites, the development of closure plans, and perpetual care and long-
term responsibility problems associated with hazardous wastes.
The newly enacted Resource Conservation and Recovery Act of 1976 provides for
the establishment of a national hazardous waste management program under the auspices
of the U.S. Environmental Protection Agency. This law requires that, within two years,
EPA must draft, promulgate and implement a comprehensive regulatory program for
hazardous wastes affecting the generators, transporters, owners pnd operators of
chemical waste facilities. The Chemical Waste Committee will continue its very
ambitious program of activities and will make the industry's experience in this field
available to the U.S. EPA and states developing and implementing hazardous waste
management programs.
At the 1974 San Francisco Conference, I had the pleasure of presenting a paper
entitled "Land Disposal: 1975-1990." That presentation was made during a time when
resource recovery held center stage and, while I managed to stir up some controversy
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on that occasion, I had a strong feeling then that speaking out strongly for land
disposal was but a voice in the wilderness. Two years have passed since that meeting
and a good measure of rationality has returned to the resource recovery area; yet, I
am sorry to note that sanitary landfill is still the neglected stepchild of the waste disposal
field.
I am sure that I need not project for you again the future role of land disposal.
There may be disagreement as to whether materials and energy recovery, or other
waste conversion systems, could handle five, ten or twenty per cent of the urban waste
generated ten years hence. The fact remains that sanitary landfill is and will continue
tc be thg primary method of waste disposal in this country at least through the end of
this century. It is very disappointing that this simple fact of life is not being communicated
to the public in clear and positive terms.
In order that the sanitary landfill may properly fulfill its important role as a
primary, or even secondary, disposal system, it is imperative that it regain a legitimate
status. Thi? can only be accomplished with the full cooperation and commitment of
the responsible federal and state agencies, not only in the implementation of the provisions
of the Resource Conservation and Recovery Act of 1976, but also in recognition of
government's responsibility — well in advance of the timetable outlined in the Act —
to continue to provide reliable and environmentally acceptable disposal to land by
expediting the landfill permitting and approval process.
With the help of government, we in the private sector can, and indeed must,
proceed immediately to develop new, urgently needed land disposal sites, making
reasonable resource allocations and risk judgments and utilizing the best that today's
technology has to offer. Delaying the establishment of new sites in anticipation of
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new definitions and guidelines will prolong the existence of sub-standard or totally
unacceptable disposal facilities and will delay the development of in-field experience
which could lead to the promulgation of better and more realistic land disposal
guidelines and standards.
The National Sanitary Landfill Committee has prepared a number of position
papers on varying important sanitary landfill subjects and has provided input to EPA
contract studies on landfill monitoring, permitting and inspection. The Committee has
also embarked on a very ambitious program of activities for the coming year which, in
conjunction with governmental activities mandated by the Resource Conservation and
Recovery Act of 1976, should bring about renewed interest and substantial improvements
in sanitary landfill design, development and operating practices.
I would be remiss if I did not acknowledge the close and cooperative relationship
which the Institute of Waste Technology has developed with the Association of State
and Territorial Solid Waste Management Officials and its past chairman Moses McCall.
We look forward to a continued close relationship with the State Solid Waste Officials
in the years to come.
As the Resource Conservation and Recovery Act of 1976 moves into implementation,
we at the Institute of Waste Technology look forward to working closely with the U.S.
EPA, the state agencies, and the Association of State and Territorial Solid Waste
Management Officials to accomplish the goals of the Act and make, what we hope
will be, a significant impact on future solid and hazardous waste management plans and
practices.
I should like to take this opportunity to express my deep appreciation and gratitude
to the Institute's past and present council and committee chairmen: John Vanderveldt,
Wayne Trewhitt, Sandy Hale, Don Shilesky, Gene Nesselson, Joe Ferrante and Jack
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Lurcott, and the many dedicated and hard-working members of their committees, for
their tremendous contribution in time and effort to the Institute, the National Solid
Wastes Management Association and the entire industry. I wish to express very
special thanks to Gene Wingerter and Jim Greco and their entire NSWMA staff for
giving so much of their time, energy, dedication and extraordinary talent to turn
the Institute of Waste Technology, in such a short time, into a most important,
visible, respected and effective arm of NSWMA and the industry as a whole. They
have made my job not only an easy one, but a most rewarding one.
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LANDFILL AND CHEMICAL WASTES DISPOSAL
-------
SITE SELECTION FOR A CHEMICAL
WASTE LAND DISPOSAL FACILITY:
MINNESOTA'S EXPERIENCE
Robert A. Silvagni
Director
Division of Solid Wastes
Minnesota Pollution Control Agency
BACKGROUND
AS MANY OF YOU KNOW, MINNESOTA WAS SELECTED BY ERA'S OFFICE OF
SOLID WASTE TO CARRY OUT ITS CHEMICAL WASTE LAND DISPOSAL DEMONSTRATION
PROJECT. THE FIVE YEAR DEMONSTRATION WILL EXAMINE THE ORGANIZATIONAL,
INSTITUTIONAL, TECHNICAL, ECONOMIC, AND SOCIAL CONSIDERATIONS INVOLVED
IN ESTABLISHING AND MAINTAINING AN ENVIRONMENTALLY SECURE CHEMICAL
WASTE LAND DISPOSAL FACILITY.
SPECIFICALLY,THE PROJECT WILL SEEK TO DEMONTRATE:
3} SITE SELECTION METHODS;
2) SITE PREPARATION TECHNIQUES TO PREVENT 6ROUNDWATER
INFILTRATION;
3) TECHNIQUES TO ADEQUATELY PREPARE WASTES FOR LAND DISPOSAL;
4) MONITORING AND SURVEILLANCE METHODS;
5} SITE MANAGEMENT TECHNIQUES INCLUDING WASTE ANALYSIS,
INVENTORY CONTROL, QUALITY CONTROL, AND COST ACCOUNT-
ING PROCEDURES ;
6^ LONG TERM CARE, LIABILITY, AND LIABILITY INSURANCE
CONSIDERATIONS:
7) PUBLIC EDUCATION METHODS, and
8) INSTITUTIONAL REVIEW PROCEDURES,
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AT THE PRESENT TIME, THE PROJECT IS IN THE STEP ONE PHASE,
THE OBJECTIVE OF STEP ONE is TO PRODUCE A PRELIMINARY FACILITY PLAN.
THIS PLAN WILL INCLUDE THE SITE SELECTION METHODOLOGY, THE RESULTS OF
THE INITIAL PHASES OF SITE SELECTION, WASTE CHARACTERIZATION STUDIES, AND
A CONCPPTUAL FACILITY DESIGN. STEP ONE WILL BE COMPLETED IN THE SPRING
OF 1977.
STEP Two WILL CONTINUE FROM STEP ONE AND BRING THE PROJECT
THROUGH FINAL SITE SELECTION, ENVIRONMENTAL REVIEWS, ECONOMIC IMPACT
STUDIES, FINAL FACILITY DESIGN, AND PERMIT REVIEW AND ISSUANCE. THE
LENGTH OF TIME FOR STEP TWO WILL DEPEND ON THE PUBLIC REVIEW OF THE SITE,
DESIGN, AND THE POTENTIAL FOR ADVERSE ENVIRONMENTAL IMPACT, OUR CURRENT
PROJECTIONS ESTIMATE THAT STEP TWO WILL CONCLUDE BY MID-1978 WITH
FACILITY OPERATION COMMENCING IN LATE 1978.
TODAY, I WOULD LIKE TO DISCUSS ONE OF THE MOST CRUCIAL ASPECTS
INVOLVED IN ESTABLISHING A CHEMICAL WASTE LAND DISPOSAL FACILITY. THAT
ASPECT IS THE SITE SELECTION PROCESS. FlRST, A GENERAL OVERVIEW AND
ANALYSIS OF PAST SITE SELECTION METHODS WILL BE PRESENTED, FROM THE
ANALYSIS OF PAST METHODS, THE APPROACH WHICH IS BEING USED IN MINNESOTA
WILL BE DESCRIBED. FINALLY, THE MINNESOTA APPROACH WILL BE EVALUATED
WITH RESPECT TO ITS COST EFFECTIVENESS, ADAPTABILITY TO OTHER REGIONS,
AND THE LONG TERM CONSEQUENCES OF ITS USE.
ANALYSIS OF PAST f-ETHODS
IN THE PAST, FACILITY ORGANIZERS HAVE EMPLOYED VARIOUS METHODS
FOR SELECTING THE LOCATIONS OF THEIR CHEMICAL WASTE DISPOSAL SITES.
THESE METHODS HAVE EMPHASIZED LAND COST, NEARNESS TO WASTE SOURCES, EASE
OF ACQUIRING THE LAND, AND EASE OF SITE APPROVALS. TODAY, AS WE BEGIN
TO LEARN MORE ABOUT THE LONG TERM CONSEQUENCES OF DISPOSAL OF INDUSTRIAL
WASTES, CONSIDERABLY MORE EFFORT IS BEING DIRECTED TO SECURING SITES
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WHI-CH CAN BEST PROVIDE PROTECTION OF GROUND AND SURFACE WATERS FROM
LEACHATE GENERATED. IN SHORT, THE DECISION-MAKING ENVIRONMENT FOR
SELECTING A SITE FOR A CHEMICAL WASTE AND DISPOSAL FACILITY IS CHANGING
THIS NEW DECISION-MAKING ENVIRONMENT INCLUDES NEW TECHNOLOGY, LEGAL
INCENTIVES TO REQUIRE COMPREHENSIVE SITE EVALUATION PRIOR TO SITE
CONSTRUCTION, AND MORE OPEN PUBLIC REVIEW TO CONSIDER PRESENT AND FUTURE
LAND USE, LONG TERM CARE OF THE SITE, OPERATIONAL SAGETY OF THE SITE,
AND ALTERNATIVE METHODS TO MANAGE THESE WASTES,
IN THE PAST, THE MOST POPULAR METHODS OF SITE SELECTION WERE
NORMALLY THOSE WHICH REQUIRED THE LEAST COST AND INVOLVED THE FEWEST
NUMBER OF PEOPLE AND GOVERNMENTAL AGENCIES. USING LAND ALREADY OWNED
AND PARTIALLY DEVELOPED, ACQUIRING LAND FROM A SYMPATHETIC OR UNKNOWING
BUYER, WERE THE EASIEST AND CHEAPEST METHODS OF SITE SELECTION. TOO
OFTEN THESE HAVE ALSO PRODUCED THE BIGGEST HEADACHES AND POCKETBOOK
PAINS FOR SITE OWNERS. SlTES WHICH HAVE BEEN SELECTED SOLELY ON THE
BASIS OF COST AND EASE OF PURCHASE HAVE OFTEN BEEN SITES WHICH HAVE
CAUSED CONSIDERABLE ENVIRONMENTAL DAMAGE, DAMAGE WHICH IS EXTREMELY
COSTLY TO CLEAN UP.
BECAUSE THE OLD SITE SELECTION METHODS HAVE so OFTEN RESULTED
IN SOURCES OF POLLUTION, INDUSTRIAL WASTE DISPOSAL FACILITIES HAVE
ACQUIRED A PUBLIC IMAGE AKIN TO NUCLEAR POWER GENERATING FACILITIES.
IT HAS ALSO BECOME IMPORTANT TO CONSIDER THE GENERAL PUBLIC AND ITS
RESPONSE TO SITE SELECTION AS A FACTOR IN THE DECISIONS REGARDING SITE
SELECTION. THE ISSUE OF PUBLIC EDUCATION IS AN IMPORTANT ELEMENT IN
ESTABLISHING A CHEMICAL WASTE LAND DISPOSAL FACILITY, BUT MUST BE THE
SUBJECT OF A SEPARATE DISCUSSION AT SOME OTHER TIME. FOR NOW, I WOULD
PREFER TO CONCENTRATE ON THE OVERALL APPROACH TO CITE SELECTION WHICH
IS BEING DEMONSTRATED IN MINNESOTA.
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MINNESOTA'S APPROACH
To UNDERSTAND THE APPROACH TO SITE SELECTION WHICH WE HAVE
DEVELOPED IM MINNESOTA FOR THE DEMONSTRATION PROJECT, KNOWLEDGE OF THE
DECISION-MAKING ENVIRONMENT IS IMPORTANT. THE LEGAL INCENTIVES TO
SELECT AN ENVIRONMENTALLY ADEQUATE SITE ARE VERY STRONG. IN ADDITION TO
A STATE ENVIRONMENTAL IMPACT STATEMENT PROCESS, WE WILL HAVE COMPREHENSIVE
STATE REGULATIONS FOR ALL ASPECTS OF HAZARDOUS WASTE MANAGEMENT. THE
PROPOSED STATE REGULATIONS WILL ADDRESS THE HANDLING OF HAZARDOUS WASTE
FROM THE SOURCE OF ITS GENERATION THROUGH TRANSPORTATION TO ULTIMATE
DISPOSAL. THE RESPONSIBILITIES AND DUTIES OF EACH PARTY INVOLVED IN
WASTE MANAGEMENT ARE CLEAR AND WELL DEFINED. WASTE FACILITY PROPOSERS
MUST SUBMIT DETAILED PRELIMINARY PLANS AND FINAL APPLICATIONS FOR REVIEW
BY THE STATE. IF NECESSARY, REVIEW BY A PUBLIC HEARING WILL BE PROVIDED.
DURING THIS REVIEW PROCESS, PROPOSALS WILL BE EVALUATED WITH RESPECT TO
THE PROPOSED FACILITY'S CAPABILITY TO SAFELY HANDLE AND DISPOSE OF THOSE
WASTES WHICH ARE PROPOSED TO BE ACCEPTED, AND FINANCIAL ARRANGEMENTS
FOR LONG TERM CARE MUST BE ASSURED. IN ADDITION TO THE ATTENTION
PAID TO PROPOSED HAZARDOUS WASTE FACILITIES BY PUBLIC AGENCIES,
MINNESOTA, LIKE MANY OTHER STATES ENJOYS A HIGH LEVEL OF CITIZEN
PARTICIPATION IN ISSUES RELATING TO THE ENVIRONMENT, AND THIS PROJECT
IS CERTAIN TO CATCH THE ATTENTION OF THE GENERAL PUBLIC AS WELL AS THE
COMMUNITY ULTIMATELY SELECTED AS THE LOCATION FOR THE SITE.
FROM THE PERSPECTIVE OF THE CHANGES COMING ABOUT IN THE
DECISION-MAKING ENVIRONMENT SURROUNDING THE CHEMICAL WASTE FACILITY,
THE BASIC GUIDELINES AND STEPS TO SITE SELECTION WILL NOW BE PRESENTED.
-------
THE FIRST STEP TO SITE SELECTION IS TO DETERMINE WHAT THE FACILITY
WILL DO AND HOW IT WILL DO IT. DETAILED SITE AND ENGINEERING PLANS ARE
NOT NECESSARILY REQUIRED AT THIS POINT, RATHER THE BASIC CONCEPTS
BEHIND THE FACILITY SHOULD BE FORMULATED. QUESTIONS SUCH AS I WILL THE
FACILITY HANDLE ONE WASTE STREAM OR A WIDE VARIETY? HOW MUCH LAND WILL
BE REQUIRED? 1'llLL THE FACILITY HAVE WASTE TREATMENT PRIOR TO ULTIMATE
DISPOSAL? WHAT ARE THE WASTE SHED AND WASTE CENTROID CHARACTERISTICS?
IS THEIR A NEED FOR NEARBY SEWER HOOK-UP? ARE SOME OF THE FUNDAMENTAL
DETERMINATIONS MADE PRIOR TO ANY SITE SELECTION WORK?
THE SECOND STEP IN THE SITE SELECTION PROCESS IS THE MOST CRUCIAL
TO ITS OVERALL AND LONG TERM SUCCESS: FORMULATION OF A WELL REASONED
SITE SELECTION CRITERIA. How THIS CRITERIA SHOULD BE DEVELOPED WILL BE
DISCUSSED SHORTLY.
THE THIRD STEP IN THE SITE SELECTION PROCESS IS TO DEFINE A MAJOR
GEOGRAPHICAL SEARCH AREA. IN OUR CASE, THE MAJOR SEARCH AREA IS THE
SEVEN COUNTY METROPOLITAN TWIN ClTIES REGION. IN OTHER CASES IT COULD BE
AN ENTIRE STATE, A COUNTY, OR A CLUSTER OF COUNTIES. THE SELECTION OF
THE MAJOR SEARCH AREA SHOULD DEPEND UPON THE GEOGRAPHICAL REGION TO BE
SERVED BY THE FACILITY.
THE FOURTH STEP IN THE PROCESS IS TO APPLY THE CRITERIA FORMULATED
IN THE SECOND STEP AGAINST AVAILABLE INFORMATION AMD DATA ON THE MAJOR
SEARCH AREA TO IDENTIFY A NUMBER OF DISCRETE MINOR SEARCH AREAS, SOURCES
OF DATA INCLUDE THE SOIL CONSERVATION SERVICE, MAJOR UNIVERSITY STUDIES,
STATE AND FEDERAL GEOLOGIC SURVEYS, LOCAL PLANNING CCHMSSIONS, WELL
DRILLING LOGS, STATE AGENCIES, AND LAND USE STUDIES PREVIOUSLY CONDUCTED.
THE FIFTH STEP IN THE PROCESS IS TO IDENTIFY CANDIDATE SITES BY
FURTHER, MORE DETAILED EVALUATION OF THE MINOR SEARCH AREAS USING THE
SITE CRITERIA AS A GUIDE. AT THIS POINT, SOf-iE ACTUAL INFIELD OBSERVATION
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OF THE AREAS SHOULD BEGIN, IF THE INFORMATION IS REASONABLY ACCURATE
AND YOUR CRITERIA IS CAREFULLY FORMULATED, LARGE LAND AREAS SHOULD BE
EXCLUDED FROfl FUTURE CONSIDERATION AT THIS POINT, THE EMPHASIS UP TO
THIS STEP SHOULD BE TO ELIMINATE THOSE AREAS WITH THE GREATEST LIMITATION
TO USE AS A CHEMICAL WASTE LAND DISPOSAL FACILITY.
THE SIXTH AND FINAL STEP IN THE SITE SELECTION PROCESS IS THE
SELECTION OF THE MOST FAVORABLE SITE WHICH ALSO MEETS MINIMUM PERFORMANCE
STANDARDS, THIS IS DONE BY CONDUCTING PROGRESSIVELY MORE DETAILED SITE
EVALUATIONS ON THE CANDIDATE SITES DEFINED IN THE PREVIOUS STEP WITH THE
SITE SELECTION CRITERIA AS A GUIDE FOR COMPARING SITES, THE DATA BASE
FOR MAKING SITE EVALUATIONS AT THIS LEVEL DEPENDS ENTIRELY ON FIELD
INVESTIGATIONS AT THE CANDIDATE SITES,
THE SIX STEP PROCESS OF SITE SELECTION ATTEMPTS TO CONDUCT A
COMPREHENSIVE SITE SEARCH BASED ON PRESENTLY AVAILABLE INFORMATION USING
A WELL REASONED SITE CRITERIA, ONE OF THE STRENGTHS OF SUCH A PROCESS
IS THAT IT GIVES EQUAL CONSIDERATION TO ALL AREAS WITHIN THE MAJOR SEARCH
AREA. BY INITIALLY CONSIDERING ALL AREAS WITHIN THE MAJOR SEARCH AREA AND
ELIMINATING THOSE PORTIONS WHICH HAVE OBVIOUS LIMITATIONS, A RATIONAL,
SYSTEMATIC, AND RELATIVELY COST EFFECTIVE APPROACH TO SITE SELECTION IS
ACHIEVED.
IN FORMULATING A WELL REASONED SITE SELECTION CRITERIA, THE
FOLLOWING GUIDELINES SHOULD BE OBSERVED:
l) FIRST, THE CRITERIA SHOULD CONTAIN A NUMBER OE PARAMETERS
TO BE EVALUATED. SOILS, TOPOGRAPHY, GEOLOGY, HYDROLOGY,
LAND USE, ENGINEERING SUITABILITY, AND TRANSPORTATION ARE
OBVIOUS FACTORS TO BE CONSIDERED IN ANY SITE. OF COURSE,
OTHERS MAY BE INCLUDED.
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2) SECOND, THE EVALUATION AND MEASUREMENT OF EACH PARAMETER
SHOULD FOLLOW GENERALLY ACCEPTED METHODS AND TECHNIQUES,
SUCH EVALUATIONS SHOULD STRESS OBJECTIVE AND QUANTIFIABLE
MEASUREMENTS OF EACH PARAMETER,
3) THIRD, THE INFORMATION REQUIRED TO MAKE INITIAL JUDGEMENTS
SHOULD BE BASED ON AVAILABLE INFORMATION, MOST SITE SELECTION
EXERCISES HAVE AND ARE EXPECTED TO OCCUR NEAR LARGE INDUSTRIAL
CENTERS, THESE AREAS TYPICALLY HAVE BEEN STUDIED INTENSIVELY
BY GOVERNMENT, ACADEMIC INSTITUTIONS, AND PRIVATE INTERESTS.
SOIL MAPS, LAND USE STUDIES, WELL LOGS, GEOLOGIC PROFILES,
AND DEMOGRAPHIC INFORMATION SHOULD BE READILY AVAILABLE AND
FAIRLY CURRENT. IN MORE REMOTE REGIONS WHERE LITTLE INFORMATION
IS AVAILABLE, FACILITY PROPOSERS MAY HAVE TO COLLECT THEIR OWN:
BACKGROUND DATA.
V) FOURTH, EACH PARAMETER SHOULD BE EVALUATED INDEPENDENTLY
RATHER THAN ON A WEIGHTED AVERAGE BASIS SO THAT THE IMPORTANCE
OF EACH PARAMETER TO THE OVERALL EVALUATION CAN BE ASSESSED.
WEIGHTED-AVERAGE METHODS SHOULD BE AVOIDED FOR TWO REASONS:
FIRST, THE WEIGHT ASSIGNED TO A GIVEN PARAMETER IS MADE ON A
SUBJECTIVE BASIS AND SECOND, THE RELATIONSHIPS AMONG PARAMETERS
ARE NOT NECESSARILY ADDITIVE. FOR EXAMPLE, ASSUME THAT A SITE
UNDER CONSIDERATION IS EVALUATED ON ONLY THREE FACTORS: LAND
USE, SOILS, AND GEOLOGIC CONDITIONS. AFTER INITIAL EVALUATION,
EXCELLENT MARKS IN THE LAND USE AND SOILS ARE SCORED, BUT THE
SITE LIES OVER AN ACTIVE FAULT. WHEN WEIGHTS AND VALUES ARE
ASSIGNED TO EACH PARAMETER AND THE SCORES ARE SUMMED, IT IS
POSSIBLE THAT THIS SITE COULD COME OUT WELL AHEAD OF OTHER
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OF OTHER SITES WHICH HAVE MODERATE MARKS FOR ALL PARAMETERS.
I THINK MANY OF YOU WILL AGREE THAT SITING CHEMICAL WASTE
I
DISPOSAL FACILITIES OVER ACTIVE ''MJLTS IS ENTIRELY OUT OF THE
QUESTION. THIS PARTICULAR EXAMPLE MAY BE A BIT EXTREME, BUT
IT DOES POINT OUT THE WEAKNESS OF THE WEIGHTED-AVERAGE METHOD
OF INTERPRETING THE RESULTS OF SITE SELECTION.
B) THE FIFTH GUIDELINE FOR DEVELOPING A WELL REASONED SITE
CRITERIA IS THAT THE CRITERIA SHOULD ESTABLISH CERTAIN MINIMUM
PERFORMANCE STANDARDS. BY ESTABLISHING MINIMUM STANDARDS, THE
SITE WHICH IS ULTIMATELY SELECTED WILL NOT ONLY BE THE MOST
FAVORABLE AMONG THOSE CONSIDERED, BUT IT WILL BE ACCEPTABLE
FROM THE STANDPOINT OF EACH MAJOR SITE PARAMETER. To ILLUSTRATE
THE IMPORTANCE OF ESTABLISHING MINIMUM STANDARDS, LET'S GO
BACK TO THE PREVIOUS EXAMPLE WHERE LAND USE, SOILS, AND GEOLOGY
ARE THE PARAMETERS, AND SUPPOSE THAT THE MAJOR SEARCH AREA LIES
OVER AN ACTIVE FAULT. THE SITE SELECTION PROCESS WILL PRODUCE
A "MOST FAVORABLE" SITE WHICH ALSO LIES OVER THE FAULT, AGAIN,
DUE TO THE OBVIOUS LIMITATION OF AN ACTIVE FAULT, NONE OF THE
SITES IN THE MAJOR SEARCH AREA SHOULD BE SELECTED REGARDLESS
OF THE SCORES WHICH THEY MIGHT RECEIVE AFTER COMPREHENSIVE
EVALUATION.
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iHE FINAL RESULT OF THE COMPUTER ASSISTED SEARCH IS THE IDENTIFICATION
OF MINOR SEARCH AREAS.
THE USE OF THE COMPUTER IN PARING THE MAJOR SEARCH AREA DOWN
TO A DISCRETE NUMBER OF MINOR SEARCH AREAS HAS A NUMBER OF ADVANTAGES:
l) IT IS OBJECTIVE.
2) IT MAKES USE OF AVAILABLE INFORMATION.
3) IT MINIMIZES SUBJECTIVE JUDGEMENTS.
*0 IT CONSIDERS THE ENTIRE MAJOR SEARCH AREA RATHER THAN
ARBITRARILY SELECTED LOCATIONS WITHIN THE MAJOR SEARCH AREA.
S) IT IS VERY FAST. As LONG AS THE RAW DATA IS IN PLACE, THE
RATE LIMITING FACTOR IS THE TIME NECESSARY TO FORMULATE AN
ACCEPTABLE RATING SYSTEM.
6) IT IS RELATIVELY INEXPENSIVE. APPROXIMATELY $2,000 WAS
REQUIRED FOR THE COMPUTER TIME, CODING, PROGRAMMING, AND
INTERPRETATION OF RESULTS IN OUR CLASS.
DESPITE ITS STRENGTHS, THE COMPUTER-ASSISTED SITE SELECTION TECHNIQUE
DOES HAVE SOME LIMITATIONS.
ij THE ACCURACY OF THE RAW DATA IS HIGHLY DEPENDENT ON THE AGE
AND COMPLETENESS OF THE ORIGINAL SOURCE. IT IS ALSO
DEPENDENT UPON THE PERSON INTERPRETING THE DATA.
2) THERE ARE LIMITATIONS TO THE KIND OF DATA STORED IN THE
COMPUTER.
3) THE COLLECTIVE JUDGEMENTS OF A PANEL OF "EXPERTS" MAY
INTRODUCE CERTAIN BIASES INTO THE INTERPRETATION OF THE DATA.
EVEN THOUGH CERTAIN CONCLUSIONS CAN BE REACHED 'FOLLOWING
THE COMPUTER ASSISTED PROCESS, PROJECT ORGANIZERS MUST
UNDERSTAND THAT CONSIDERABLY MORE TIME AND RESOURCES MUST BE
BE EXPENDED TO REACH CONCLUSIONS REGARDING THE FINAL SHE
SELECTION.
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CONCLUSIONS
THE SITE SELECTION PROCESS WHICH HAS BEEN PRESENTED TODAY IS
THE RESULT OF A MAJOR CHANGE IN THE DECISION-MAKING ENVIRONMENT
SURROUNDING THE ESTABLISHMENT OF NEW CHEMICAL WASTE DISPOSAL FACILITIES.
THIS DECISION-MAKING ENVIRONMENT IMPOSED BY STATE AGENCIES, LOCAL
AUTHORITIES, AND MORE RECENTLY THE FEDERAL GOVERNMENT,WILL REQUIRE
WASTE DISPOSAL FACILITY ORGANIZERS TO MORE CAREFULLY CONSIDER THE SHORT
AND LONG TERM ENVIRONMENTAL CONSEQUENCES OF A PROPOSED WASTE FACILITY
AND ITS LOCATION.
THE SITE SELECTION PROCESS PRESENTED TODAY APPEARS TO BE A
RATIONAL, SYSTEMATIC, AND THOROUGH METHOD OF SELECTING A SUITABLE
LOCATION FOR A CHEMICAL WASTE FACILITY, WlTHIN THE CONSTRAINTS OF THE
DECISION-MAKING ENVIRONMENT IN MINNESOTA, IT ALSO APPEARS TO BE A COST
EFFECTIVE METHOD FOR SITE SELECTION BY EMPHASIZING THE USE OF CURRENTLY
AVAILABLE INFORMATION WHICH IS QUICKLY AND EFFICIENTLY MANAGED BY A
COMPUTER AFTER INSTRUCTION FROM A VARIETY OF KNOWLEDGEABLE PEOPLE.
I WOULD LIKE TO AGAIN THANK THE NSWMA FOR THIS OPPORTUNITY TO
PRESENT THIS STATUS REPORT ON THE DEMONSTRATION PROJECT AND HOPE THAT
WE MAY RETURN TO DISCUSS OTHER RESULTS OF THE PROJECT AS THEY BECOME
AVAILABLE.
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I WOULD LIKE to MOVE NOW FROM THE SUBJECT OF SITE CRITERIA TO
THE SUBJECT OF HOW WE, IN MINNESOTA, HAVE APPROACHED THE EVALUATION
OF A MAJOR SEARCH AREA. To AID IN THIS EVALUATION, A COMPUTER WAS
USED TO STORE, COLLATE, AND PRODUCE INTERPRETIVE "DATA MAPS"SHOWING
THOSE AREAS WITHIN THE MAJOR' SEARCH AREAS WHICH CAN BE ELIMINATED FROM
FURTHER CONSIDERATION AND IDENTIFY THOSE AREAS WHICH SHOW THE LEAST
LIMITATION ON THEIR USE AS A WASTE DISPOSAL SITE. THIS COMPUTER BASED
TECHNIQUE WAS DEVELOPED BY THE UNIVERSITY OF MINNESOTA IN ITS CENTER
FOR URBAN AND REGIONAL AFFAIRS FOR APPLICATION IN A WIDE VARIETY OF LAND
USE RELATED EVALUATIONS.
THE FIRST STEP IN MAKING USE OF THE COMPUTER-ASSISTED
TECHNIQUE IS TO ASSEMBLE THE AVAILABLE INFORMATION AND PLACE IT IN
THE COMPUTER. FOR THIS PARTICULAR SYSTEM, THE MAJOR SEARCH AREA WAS
BROKEN INTO 40 ACRE PARCELS, THE TOTAL NUMBER OF PARCELS WAS
APPROXIMATELY 47/000. NEXT, THE AVAILABLE INFORMATION WAS COLLECTED,
INTERPRETED, AND ENCODED IN A FORM UNDERSTANDABLE TO THE COMPUTER.
SOURCES FOR THIS DATA BASE INCLUDED:
AERIAL PHOTOS, U.S. GEOGRAPHIC SURVEY TOPOGRAPHIC MAPS, SOIL MAPS
FROM THE SOIL CONSERVATION SERVICE AND THE UNIVERSITY OF MINNESOTA.,
LAND USE PLANS, AND LAND OWNERSHIP SURVEYS. NEXT, A COMMITTEE OF
TECHNICAL EXPERTS AND PUBLIC AGENCY REPRESENTATIVES FORMULATED A
RATING SYSTEM WHICH EVENTUALLY BECAME AN INSTRUCTION SET FOR THE
COMPUTER, THE COMPUTER WILL TAKE THE DATA AND INSTRUCTIONS AND PRINT
OUT A SERIES OF INTERPRETIVE MAPS SHOWING THE DEGREE OF LIMITATION FOR
EACH LOCATIONAL FACTOR. WlTH APPROPRIATE INSTRUCTIONS, THE COMPUTER
CAN ALSO OVERLAY THE RESULTS OF AN INTERPRETIVE MAP FOR ONE FACTOR ON
OTHER MAPS TO GIVE A TOTAL PICTURE OF WHERE THE MINOR SEARCH AREAS
MAY LIE AND WHAT AREAS CAN BE ELIMINATED FROM FURTHER CONSIDERATION
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GROUND WATER PROTECTION SYSTEMS-
WHERE THEORY MEETS PRACTICE
John Reinhardt, Chief
Solid Waste Management Section
Wisconsin Department of Natural Resources
The possible pollution of ground water by landfill sites is becoming of
greater concern to the public. In a number of instances, raising it as
an issue is used by the opposition to block the establishment of a
disposal site.
"How serious are the impacts of land disposal sites on ground
water?"
"Isn't this issue really an over reaction on the part of environmental-
ists and alarmists?"
"After all, no one ever died from drinking leachate did they?"
In my opinion, the impact of landfills on ground water can be very
serious. The issues raised by the potential for ground water pollution
by landfill sites will have far reaching impacts on the solid waste
industry if in some areas, landfills will be permitted in at all, where
they will be located, how they will be designed, who actually will own
them and the economics of disposal.
As far as I know, to date, it has not been established that any human
has died from leachate. Maybe someone in the audience can correct me on
this. This is probably due only to the difficulty in getting water
polluted with leachate past one's nose. Damage assessment at many older
existing landfill sites in Wisconsin indicates many cases of undrinkable
water in the immediate vicinity of the landfills due to the landfill.
The Congressional Record, September 27, 1976 documents the serious
economic consequences of ground water pollution. Congress is requested
to provide $650,000 for the correction of the ground water pollution
problem at the Llangollen landfill in New Castle County, Delaware.
$2,000,000 already has been spent on the problem. The operating costs
of the present barrier well protection system is 5200,000 per year, and
total estimated costs for correction range from an estimated $15,000,000
to $25,000,000. An expenditure of this magnitude, by any public or i
private landfill owner, would certainly be a financial disaster. Admittedly,
the Llangollen landfill was an old existing site established at a time
when little or nothing was known about the undesireability of establishing
a site in a gravel pit. However, sites are being established today, in
which you and I are playing a role, which could have such an impact if
we are wrong in our analysis of what ground water protection systems are
required or if these systems fail.
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Landfill site operators, consultants and regulatory officials are all
facing a common dilemma, viewed from different prospectives, in establish-
ing land disposal sites for residuals. On one hand is the strict
environmental (and in some instances legal) stance that under no cir-
cumstances shall a disposal site change the ground water quality - "zero
discharge". On the other hand is the viewpoint that the waste must go
somewhere as it is produced every day. The urgency of the need to
dispose of waste, as it is generated, means a few wells or a minor trout
stream must he sacrificed here or there to prevent the garbage from
piling up on the streets; the old "end justifies the means" concept.
In between these two extremes, landfill sites must be found that provide
a high degree of protection of the ground water and also meet other
economic, social, political, legal, and environmental constraints and
requirements.
The purpose of this presentation is to describe some of the problems
with putting the theory of ground water protection systems into practice
and to provide a framework for a forum discussion of some of the dilemmas
in addressing the ground water protection aspects of landfill site
location.
The objectives of this presentation are to:
*Provide several definitions of the ground water which must be
considered in ground water protection systems.
*Point out several reasons why the ground water protection systems
must be considered in landfill site location.
*Describe some of thp more classical ground water protection
systems.
*Raise some of the more pertinent issues facing the location of
landfills from a ground water protection standpoint.
"What is 'ground water'?" The lack of a clear understanding of, and
agreement on, the various definitions of ground water on the part of the
designer can result in a regulatory agency asking for a re-evaluation of
some of the proposed concepts for ground water protection systems. If
ground water is to be protected, one has to know what it is. Ground
water is usually technically defined as water below the ground water
table. Davis & De Wiest in their text book "Hydrogeology", define
"water table" as "the surface in unconfined materials, along which th'e
hydrostatic pressure is equal to the atmosphere pressure." While this
is one of the more widely accepted technical definitions, statutory
definitions may vary from this. Chapter 162.02(2) of the Wisconsin State
Statutes defines ground waters as, "subsurface water supplied for human
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consumption." This could be interpreted to mean all water under ground.
Section 147.015(13) of the Wisconsin State Statutes, which establishes
the WPDES (Wisconsin Pollution Discharge Elimination System), specifies
waters of the state to include ground water without defining ground
water. The differences in definition must be addressed in any ground
water protection system.
Another definition of ground water, which must be considered is the
definition established by court cases. The outcome of a future lawsuit,
for alleged damages to your neighbor's ground water, could depend on the
definition put forth in a past court suit. It wasn't too long ago in
Wisconsin that a court suit talked in terms of water flowing in "underground
rivers".
An understanding that must be understood are different meanings to
ground water is necessary if ground water protection is to be meaningfully
addressed in landfill site location.
Another term that must be understood is "aquifer". It generally is
technically defined as "a formation or group of formations, or part of a
formation that contains sufficient saturated permeable intervals to
yield or be capable of yielding significant quantities of water to wells
or springs." There is, at times, a tendency to ignore shallow aquifers
capable of providing water only to domestic wells. It is important that
the designer and others with an interest in ground water protection
system understand from the start if the system needs to protect all
ground water or only certain types or classes of aquifers.
A below the zone of saturation landfill in tight clay could be polluting
the ground water as defined technically, by statutes and by court cases,
but not harming any aquifers because water cannot be withdrawn from the
clay in significant quantities even for domestic wells.
Why protect the ground water? First, there have been for some time
various state statutory obligations. Also, of present and future
significance is the Safe Drinking Water Act on the Federal level. You
can be sued by your neighbor if you pollute his ground water. Not
protecting ground water is considered anti-social; neighbors appreciate
landfills even less than they usually do if the landfill can pollute
their ground water. Neighbors near proposed landfill sites are greatly
influenced by past ground water pollution from landfills. Environmental
groups and others who oppose a particular landfill or, in fact, oppose
any landfill anywhere, can successfully stop a landfill from being
established or from continuing operation if they can show that ground
water may be polluted. Politically, no elected official can be in favor
of a Jandfill which may pollute ground water. Thus, an elected
Official must oppose any landfill which may pollute the ground water.
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In summary, the issue of ground water protection must be addressed and
resolved by those groups who are represented in the audience if landfill
is to provide a viable, residual disposal solution into the future.
The problems of putting theory into practice, in ground water protection
systems, must be overcome in a manner that they work in the field and
in a manner that the public can have confidence in them. If the "doers"
ignore the issue as they believed the "refuse has to go somewhere";
the end justified the means, then, the alternative may be the creation of
many unwisely conceived resource recovery and processing concepts in
the guise of protecting the ground water.
How can_ the ground water be protected7 The concept, in theory, is easy;
the implementation, in practice, is difficult. In concept, contaminants
from residual disposal must be prevented from reaching the ground water,
either entirely to meet statutory definitions or limited to some amount
that is legally specified or would not make the water unusable. The amount
of degradation which can be tollerated will depend on if the water is
to be used for drinking, cooling, irrigation, etc.
The traditional problem solving procedure, used in large scale engi-
neering projects, is probably the best approach to developing ground
water protection systems. This approach can be especially effective
when incorporating systems concepts of looking at alternatives and re-
evaluating solutions into it.
A clear understanding of what is to be protected, in terms of the legal,
social and technical definitions of ground water, is needed. Also, a
clear, written definition of other economic, political, and social
constraints to the problem is desirable.
A good physical definition of the actual area where the waste will be
placed, along with the surrounding area, is needed. The physical
definition of topography, surface water, geology, soils, hydrogeoLogy,
inter-relationship of aquifers, etc., is needed to assess alternate
solutions.
Theoretically, the anticipated time-rate of production of contaminants
should be determined, and the ability of the physical site location to
attenuate them should be established. The difference between contaminant
loading and the natural ability of the physical site to protect the
ground water should then be addressed through engineering design of
man-made site modification systems. Unfortunately, only in a crude way
has contaminant production been defined in terms of quality and quantity
at this time. Assessing the contaminant variation from landfills with
time is extremely difficult. If all landfills were located in homogeneous
soils with readily defined flow systems, the capacity of the site to
handle contaminants could be more easily addressed. As soils and flow
systems in nature are not always easily defined, the task is usually
difficult.
•€38-
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Thus, the theoretical approach is easy to describe, but as most of you
know through your own experience, at this time, there is a long way
between theory and practice. Landfill disposal site location and design
for ground water protection are not yet a science, let alone a well-
developed art. Some say it is a black art; others say it is an emerging
art at best. However, the development of ground water protect system theory
and practice has come a long way in the past ten years. The more
traditional 10 year time-lag of knowledge from theory to practice,
through laboratory, pilot projects, etc., has been short-circuited. The
need to do something now has necessitated placing theory directly into
practice in many cases. Only time will tell if the theory works. It
may not have always been the wisest course, but then we place waste at
the curb every day and something is better than nothing. In my opinion,
the theory that is available should be utilized to the maximum, even if
it is sometimes in an imperfect state. In order that ten years from
now,. the imperfect art we practice, today can be called even a fledging
science, we must utilize it to its maximum today.
Also, of prime importance is that the problem not be viewed from the
standpoint of meeting some minimum regulation. Minimum regulations
are just that—solutions designed around such a narrow concept are
usually short-lived and in the long run inadequate.
What are some of the major ground water protection systems which are
proposed and in use today? They can be categorized as natural pro-
tection systems, man-made systems, or combinations of both.
The most obvious approach to protecting the ground water is to limic the
amount and/or rate of leachate production by reducing water coming into
contact with solid waste. The diversion around the landfill of surface
water around the landfill from areas outside of the landfill is one of
the first engineering considerations that should be made in landfill
design. Traditional storm water design equations and concepts should be
used. The solutions are expressed in the field in terms of ditches,
storm sewers, and berms. Some civil engineers, who would not think of
designing a highway or parking lot without computing the size of
ditches and storm sewers to protect the project from storm water, do
not see the same need when designing landfills. The possibilities of
surface water entering the landfill through sand stringers, where these
sand stringers extend or surface outside the landfill, should be examined.
The sand stringer can be sealed with clay, both inside and outside the
landfill. As simple as this may seem, this approach often is not taken
in landfill design.
The location and design of cover dirt sources and stockpiles must be done in
a manner that they do not route surface water into the fill. All earth
moving activities connected with a landfill should be designed in a
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manner that they do not add water to the fill or if possible in a manner
that conducts water off the site. Many cases of unnecessary leachate
production at landfills have resulted from not considering this problem.
Leachate production can also be reduced by detailed consideration of the
handling of precipitation on the landfill site proper. Detailed phasing
plans for each cell which route surface water in a manner that it can be
directly away fill will reduce leachate. Every gallon of water that is
pumped or drained off of a refuse cell is one less gallon to infiltrate
and produce leachate. A design of the final contours and cover to
reduce infiltration can also greatly reduce leachate production. The
final contours should channelize water and provide the shortest possible
length of overland flow. Runoff can also be increased by increasing the
slope and choosing a cover material that has a low permeability and will
not readily crack. As an extreme, a man-made material such as plastic
or rubber can be used to attempt to obtain zero infiltration.
The impacts of various concepts are easily evaluated by utilizing traditional
engineering design procedures utilized in storm water design. Rational
approaches to evaluating designs are also given in the many Soil Conservation
Service manuals.
Obviously, once leachate is produced, consideration must be given to
handling it in a manner to not pollute ground water. Natural systems to
handle leachate once it is produced are generally preferable to man-made
systems. Man-made systems are usually expensive to build, operate, and
often require long-term maintenance and operation. Which system or
combination of systems should be used is dependent on detailed definition
of the site location in terms of soil type, geology, hydrogeology, and
other physical criteria. Hopefully, the site is located so that the
underlying soils will attenuate the leachate so it will not pollute the
ground water, or so it would flow through the hydrogeologic setting in a
manner not to create a problem. This approach takes advantage of soils,
upward ground water gradients, flow paths for contaminants that will
not impact on ground water use in a detrimental manner, and possibly others.
Thomas Clark, in the July-August 1975 issue of Ground Water gives a
detailed mathematical approach to evaluating a natural attenuation site.
Artificial systems vary all the way from man-made fabric liners used in
concepts which completely collect and treat leachate to wells installed
into the center of a landfill in case leachate "has to be withdrawn at a
future date".
Liners can be classified in terms of man-made materials such as rubber
and plastic or natural materials such as clay. The use of man-made
materials usually is based on the concept that no leakage will occur,
This implies collection and treatment of leachate. Use of clay or other
natural materials usually implies some leakage will occur. Thus, the
site location still must be considered as part of the ground water
protection system.
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Use of liners usually will call for leachate collection and treatment at
some time and in some manner, as in many areas of the United States
infiltration through the cover will exceed the exfiltration through the
lined bottom and sides of the fill. If the leachate is not withdrawn,
it will ultimately build up to where it will spill out on the ground.
All the problems associated with leachate collection and treatment must
be addressed. This includes the problems associated with the long-term
operation, maintenance, and financing of these systems. While there is
some question about the theory of treating leachate, increasing numbers
of projects are being reported, where treatment either is being done or
proposed. Usually the collected leachate is treated in an existing
municipal waste water treatment plant.
The combination of natural and man-made systems are being proposed for
new disposal sites and many have actually been built in the field.
These include the concept of below the zone of saturation location of
landfills in tight soils with the maintenance of inward gradients by
leachate withdrawal. This and other such concepts were discussed in
some depth as early as 1972 by George Hughes in the Illinois Geological
Survey Environmental Geology Notes.
Barrier wells, under drains, spot sealing of permeable soils are
other concepts proposed or in use. One recent concept proposes to use a
clay liner and air from an air compressor to restrict leachate from
flowing out of the landfill and carbon dioxide from migrating out of the
landfill. The problems of ground water pollution caused by methane and
carbon dioxide migration are just beginning to be addressed.
One interesting concept of choosing between complete collection and
treatment of leachate and no protection for the ground water is using
the shallow flow system adjacent to large rivers or discharge areas
which handle polluted ground water without producing major problems. A
location is chosen adjacent to a large river where the ground water flow
system is primarily horizontal toward the river. Preferably, the
site is adjacent to a flood plain where development of wells will never
occur. The flow path of the contaminants should be long enough in
time and distance that when they reach the river or discharge point,
they will not have a detrimental impact on the surface waters. Of
course, the problems with flow laterally along the river bank must also
be evaluated, along with any problems due to reversal of ground water
gradients during high river flow periods. Basically, this is a deliberate
pollution of a portion of the shallow ground water resource which is unlikely
to even be used to overcome the many problems with locating in other
settings. The approach is based on the concept that it is better to use
part of the ground water flow system where the pollution will be minor in
extent and the result predictable. An interesting version of this
approach will a step-by-step mathematical design was presented in the
April 1975 issue of Public Works by Dilaj and Lenard.
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Unfortunately, such questions as what is a natural attenuation site,
which man-made system is needed to protect the ground water to what
extent, etc., largely depended on a number of resource allocation ques-
tions which are, to a great degree, unresolved. Two of the most per-
tinent are:
*To what degree can the ground water be used for waste assimilation
from a technical, legal, social, environmental and regulatory
standpoint?
*How can the problem of waste load allocation to air, water and
land be resolved in the context of federal and state regulatory
programs and other constraints placed on the problem by society?
Two major questions must also be resolved ultimately if man-made systems
are to prove usable in the long run. These are:
*How can the issue of long-term responsibility and liability for
ground water protection at landfill sites be resolved?
*How can the public be assured that the technical concepts are adequately
translated into engineering design and then actually constructed
and operated into the field in keeping with the engineering design.
This appears to be a major problem in the immediate future which
must be overcome. Evaluation of how viable present concepts are
will be difficult, if not impossible, if they are not properly
converted to engineering design, constructed in the field, or
evaluated from data gathered in the field?
If the theory and design of ground water protection systems ever are to work
in practice, quality control of construction and operation in the field
is a necessity. If the studies and designs are only made to obtain an
approval and license from a regulatory agency, then all is lost.
Unfortunately, it is not uncommon to find engineering plans being
ignored in the field and in some instances, the landfill operator unable
to read the plans and unwilling to retain the necessary professional
help who can.
Last, but not least, translating the theory of ground water protection
systems, into practice, requires monitoring and evaluating performance.
Some view such activities as research projects for state regulatory
agencies. In my opinion, monitoring and evaluation of ground water
protection systems are of great value to the landfill owner. It provides
him proof against charges of his neighbors that he is polluting the '
ground water. It provides information for him on which to make future
investments in landfills. It allows early corrective action when designs
do not work. It also provides the landfill site with some degree of
public credibility.
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Certainly, the subject matter and issues raised in this presentation can
only be covered in some depth by a four or five-day conference. However,
this forum presents an opportunity for a wide cross-section of those
involved in landfill siting to put forth their views on the issues
raised. If those present think the issues can be ignored, there are
others who will not ignore them but will provide answers none of us will
like.
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References
Congressional Record - 11179, Volume 122, September 27, 1976, No. 147.
Clark, Thomas P. 1975, "Survey of Ground Water Protection Methods For
Illinois Landfills", Ground Water, pp. 321-331, July-August 1975.
Dilaj, M. and Lenard, John F., "Leachate Control at Landfills Based on
Hydrogeologic Studies", Public Works, pp. 91-122, April 1975.
Hughes, G. M., 1972. "Hydrogeologic Considerations in Siting and
Design of Landfills", Illinois Geological Survey. Environmental
Geology Notes, no. 51.
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CONSIDERATIONS FOR STATE HAZARDOUS
HASTE PROGRAMS
John P. Lehman
Director
Hazardous Waste Management Division
Office of Solid Waste
U.S. Environmental Protection Agency
* CONGRESSIONAL INTENT FOR STATES TO ASSUM2 HAZARDOUS
WASTE PROGRAM
EPA GUIDELINES TO ASSIST STATE PROGRAM DEVELOPMENT
* INTERIM AUTHORISATION POSSIBLE
* FEDERAL GRANTS PROVIDE) FOR INITIAL DEVELOPMENT AND
IMPLEMENTATION
• STATE PROGRAMS TO BF, "EQUIVALENT" TO FEDERAL
0 STATE PROGRAMS TO 3E "CONSISTENT" KITH FEDERAL
CT'.iER STAI"^1 PROGRAMS
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GOALS Q:-' STATS HAZARDOUS WASTK
1) COGNTZJVNC53 OVER HAZARDOUS WASTE
- SOUSCS3
- QUANTITIES
- TYPES
- DESTINATIONS
2) CONTROL OVER HAZARDOUS WASTE
- STORAGE
- TRANSPORTATION
- TREATMENT
- DISPOSAL
3) CAPABILITY TO
- PROVIDE TECHNICAL ASSISTANCE
- ENFORCE REGULATORY PROGRAM
4) ALTERNATIVES TO INADEQUATE PRACTICES
5) PREVENTION OF PUBLIC HEALTH AND ENVIRONMENTAL DAMAGES
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ELEMENTS OI-' AN EFFECTIVE STATE PROGRAM
1) LEGISLATIVE AUTHORITY
2) ADEQUATE RESOURCES
3) PUBLISHED CRITERIA AND STANDARDS
4) FACILITY PERMIT SYSTEM
5) TRANSPORTATION MANIFEST SYSTEM
6) SURVEILLANCE AND ENFORCEMENT FUNCTIONS
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SUGGESTi\0_ S^QUgNCB_01-' DEVET.pPMSNT
1) HAZARDOUS WASTE SURVEYS
- ESTABLISH SCOPE OF PROBLEM
2) STATE PLAN
- HAZARDOUS WASTE SUBSET OF SWM PLAN
- FACILITY CAPACITY NEEDS
3) LEGISLATION
- NEW OR AMENDMENTS
4) REGULATIONS
5) PERMIT PROGRAM
6) GENERATOR REPORTING
7) TRANSPORT MANIFEST SYSTEM
8) SURVEILLANCE AND ENFORCEMENT
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FULL" AUTHORIZATION OF STATE PROGRAM
0 STATES CAN APPLY AT ANY TIME
(?) ° ALL PROGRAM ELEMENTS IN PLACE (EQUIVALENT)
(?) ° CONSISTENT WITH FEDERAL AND OTHER
STATES' PROGRAMS
(?) ° FRAMEWORK AND RESOURCES FOR ENFORCEMENT
IN PLACE
(?) ° SINGLE LEAD AGENCY
(SEVERAL MAY BE INVOLVED, BUT ONE MUST
LEAD)
(?) ° INTERSTATE COOPERATION POLICY
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"INTERIM" AUTHORIZATION OF STATED PROG t
-------
ISSUES CONCERNING STATE PROGRAMS
0 FEDERAL DEFINITION OF HAZARDOUS WASTE
- BROAD OR NARROW SCOPE
0 INTERPRETATION OF
- "EQUIVALENT"
' - "CONSISTENT"
- "SUBSTANTIALLY EQUIVALENT"
0 CAN STATE PROGRAMS BE MORE STRINGENT THAN FEDERAL
PROGRAM?
0 ARE WASTE NON-IMPORTATION POLICIES FAIR TO OTHER
STATES? ARE THEY "CONSISTENT"?
0 SHOULD STATE PROGRAMS BE SELF-SUSTAINING? HOW?
USER FSSS?
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CONTROL OF HAZARDOUS WASTES IN CALIFORNIA
by
Harvey F. Collins'1' Ph.D.
The California Department of H3a1th's hazardous vMste control
program was started in the fall.of 1973 pursuant to the Hazardous
Waste Control Act of 1972, which authorized the Department to:
(1) estciblish and enforce regulations for the handling and dis-
posal of hazardous wastes; (2) provide for appropriate surveil-
lance of hazardous waste processing and disposal practices in the
state; (?) conduct appropriate studies relating to hazardous
wastes; end (4) maintain a technical reference center on hazardous
waste disposal, recycling practices, and related information for
public ard private use.
Regulations. The Department adopted regulations governing hazardous
wastes in June, 1974. These regulations list wastes determined to
be hazardous and extremely hazardous, establish requirements for
producers and haulers of hazardous wastes and for operators of
waste disposal sites, and specify approval by the Department of
Health as a prerequisite to the disposal of extremely hazardous
wastes. The regulations also established fees to be paid by
California Department of Health, Sacramento, CA
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operators of disposal sites accepting hazardous wastes. The foes
support the regulatory activities of the Department's program,
which is not funded from the State Treasury.
We have recently finalized hazardous waste regulations which the
Department proposes to adopt within the next few months after
a public hearing. These regulations will greatly expand the
Department of Health's regulatory activities. Where the present
regulations apply only to operations at waste disposal sites that
receive hazardous wastes from more than one source, the proposed
regulations will apply to operations at all disposal sites that
receive hazardous wastes. They will also apply to all transfer
stations, storage facilities, and treatment facilities that receive
hazardous wastes. The proposed regulations are far more detailed
than the present regulations and explicitly prohibit undesirable
procedures which we have observed at seme of the disposal sites.
Surveillance nnd Enforcement. The program presently has personnel
operating out of Sacramento, Berkeley and Los Angeles. Our
Inspectors make field inspections to ensure that hazardous wastes
are properly handled and disposed of. These Inspectors: (1) visit
plants and facilities where hazardous wastes are generated, processed,
and stored, (2) field-monitor the haulers of hazardous wastes to
discourage Illegal disposal at unauthorized disposal sites; and
(3) visit hazardous waste disposal sites to Inspect the sites and
audit records of receipt of hazardous wastes. Since April 1976
when we Initiated our. Intensive field efforts, we have visited
161 factories or plants which generate hazardous wastes and have
made 210 visits to sites where such wastes are disposed of.
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A total of /C Illegal hazardous waste disposals or unsafe handling
practices has. been found by our Inspectors. In most cases these
Irregularities were rectified by Informing the waste handler of the
law and providing him with guidance on proper methods to handle and
dispose of his waste. In four cases the violations were serious
enough that we have sought legal action.
Thr Hazardous Waste Control Act requires that each load of hazardous
waste transported in California be accompanied by a manifest v;hich
describes the composition and volume of the waste. Disposal :.K?
operators are required to sign the manifests when the waste loads
are accepted at their sites and mail copies to the Department on a
monthly basis.
We receive several thousand manifests each month and enter the
reported information into a computer. Each month the computer
prepares a report that shows the types and volumes of hazardous
wastes disposed of, the firms which generated the wastes, and the
disposal sii.cs used. The computerized data aids the Department 1n
Its enforcement program and 1n program planning.
S_tud1es (Field Surveys). The Department 1s conducting studies of
the generation of all hazardous wastes, including those which a>-e
disposed of on land owned by waste producers. We are visiting
plants and factories to determine the volumes and typos of Industrial
wastes produced and how they are disposed of. The data will aid the
Department 1n its regulation of the management of hazardous wastes
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and 1n its development of periodic publications which will report to
the industries what types of wastes are available from other indus-
tries for use by them.
We have enlisted the help of local agencies to survey some of the
counties. Six counties^ ' have been surveyed with the aid of
(2)
county or other local agencies. Nine other counties ' are now
being surveyed by county health agencies with financial and technical
aid from the Department. Fifteen other counties will soon be sur-
veyed by Departmental and county staff. In February we expect to
have an estimate of the amounts of all hazardous wastes disposed of
throughout the state, including wastes disposed of on land owned by
waste producers.
PROBLEMS
Difficulties we have encountered have mostly resulted from adminis-
trative problems inherent in the initial developmental phase of a
regulatory program. The one significant exception is that we do
not have a practical means to discourage clandestine disposal of
Amador, Alameda, San Benlto, Santa Cruz, Monterey, and Ventura
(2}
v 'Kern, Kings, Fresno, Madera, Mariposa, Merced, San Joaquln,
Stanislaus, Tulare
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hazardous wastes. The throat of revocation of a permit needed to
handle hazardous wastes would provide a proper disincentive against
such activity, as would the threat of iRposltion of a stiff monetary
fine.
Our proposed regulations will require that all operators of facilities
who transfer, store, treat, or dispose of hazardous waste have a
permit Issued by the Department and will provide for revocation of
the permit of any who violate the regulations. We have proposed
.legislation for review by the Health and Welfare Agency and by the
Governor that would prohibit the hauling of hazardous waste by
persons who do not hold a license Issued by the Department and
which would authorize the Department to revoke the license for due
cause.
The proposed legislation would also ^.thorlze imposition of a sub-
stantial monetary fine for violations. The Federsl Resource Recovery
Act of 1976 provides a precedent for such legislation, as 11 empowers
the EPA to Impose monetary fines on violators of federal requirements.
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CONSIDERATIONS REGARDING HAZARDOUS
WASTE REGULATORY POLICY ALTERNATIVES
Rosalie T. Grasso
Manager
Research Program
National Solid Wastes Management Association
-------
The Resource Conservation and Recovery Act 1976 (P.L. 94-580) at the
outset recognizes the greater potential for health and environmental harm
by requiring a greater degree of regulation than non-hazardous wastes
management. The option to have or not to have a hazardous waste manage-
ment program has been eliminated with the passage of this Act. We are
not here to discuss the greater potentials for harm in hazardous waste
management, but to discuss the different regulatory philosophies and
attendant enforcement options. In conjunction with the need for health
and environmental protection, the law also stresses resource conservation.
This term is normally associated with resource recovery and materials
policy decision-making. However, a policy of resource conservation
pervades all sections of the law, including Subtitle C, Hazardous Waste
Management. Therefore if resource conservation (that is, the maximum
utilization of materials and optimum protection of resource -- land,
water and air) is adopted as a regulatory philosophy, the implementation
agency will bias its decision-making in the permit process with policies
to provide further requirements for materiel recovery from residuals,
or energy potential, rather than solely a concern for the safe deposition
of hazardous waste to the land. The Association through IWT-Chemical
Waste Committee and its testimony throughout the legislative history of
on
P.L. 94-580 and/several EPA guidances on hazardous waste management has
supported consideration of priority management alternatives(in order)
which are - waste reduction, waste separation, waste exchange, energy/
material recovery, treatment secure landfill. Given this scheme of
descending alternatives, the implementation agency-Federal,state-will
and can be expected to implement this philosophy in the permitting process.
For example, requiring that a specified percentage of a waste stream be
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recovered or the prohibition of mixed wastes entirely in order to facil-
itate recovery.
The third goal of the act in relation to protection of public health and
environment is the prohibition of open dumps. This will be evidenced
as an affirmative, direct aggressive program of enforcement to identify,
close or upgrade undesirable disposal options. However, a less apparent
consideration is whether or not in developing regulatory provisions such
degree of control is mandated; thereby, resulting in severe financial
impact on acceptable disposal alternatives that open dumping is indirectly
fostered as a viable option.
In the development of a regulatory program and its components - rules,
standards, regulations, permit process, inspection and enforcement --
the maximum protection of human health and the environment, conservation
of resource, and the closing of improper disposal "lethods will predominate
in the selection of regulatory options.
Criteria
Criteria for determining whether or not a waste is hazardous should be
based upon the characteristics of a waste rather than its functional
origins. That is, a waste is hazardous because it is carcinogenic
(characteristic) rather than its generation by a commercial/industrial
activity (origin). The identification of waste by source is an inventory
method, not a sole criteria for determination of degree of hazard. The
conscious decision to solely regulate waste stream from commercial/
industrial should be based upon the known volume and types of hazardous
waste from those sources as a percentage of the total volume of hazardous
wastes and the degree of hazard evidenced existing budgetary and staffing
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limitations must also be reflected in determining the level of enforcement
program feasible. That is, if only given number of hazardous waste
sources can be monitored and regulated, selection should based upon the
type sources proportion to overall volume of hazardous waste generated
and the degree of hazard in specific waste stream type. An example,
several sources may generate a particular type waste (e.g. "sludge").
The sources may be commercial, industrial, or institutional facilities.
Based upon a given criteria for determining a hazardous waste, only a
few waste streams may be classified as hazardous, some of which may be
industrial and/or institutional.
Regulations should be based on criteria for waste characteristics with
established thresholds as in given LD -mg/ky body weight. This reg-
ulatory alternative will narrow and focus enforcement capabilities.
This alternative is preferable rather than a process of elimination
based on function, size or type of industry.
The development of criteria should consider —- oral toxicity, dermal
toxicity, acidity, alkalinity, inhalation toxicity, bioaccumulation,
genetic effect, aquatic toxicity, phytotoxicity, infectious, corrosivity,
flammability, and reactivity. While data may not be available for all
waste types, the criterium should not be eliminated but developed.
Different levels of hazard can be determined on the basis of
o direct exposure;
o dilution-waste, leachate;
o existing standards-air, water, transport.
The level of hazard should not solely focus on the impact of land disposal
of hazardous waste. The law requires Environmental Protection Agency to
develop and promulgate criteria for hazardous waste determination as
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well as listing hazardous wastes. Consequently, regulatory programs
in the long term can be expected to develop based upon waste characteristics
rather than solely upon point of generation of a waste.
The permit process can be responsive to this development and may provide
exemptions based upon level of toxicity, etc., volume, rather than by
specific identity of a source type. Options may be available in deter-
mination of numeric levels for each characteristic dependent upon a
specific methodology testing such as standard leaching test, standard
attenuation procedure and NIOSH documentation. Two generic approaches
can be taken in selecting numeric criteria for designating hazardous waste--
o compatibility with existing definitions and
o use of a reasonable scenario describing a manner in
which a waste may pose a hazard.
If the latter generic approach is utilized, criteria may develop on the degree
of hazard posed by a v;aste characteristic at a point iii time in the inanacie-
ment program. Permit ^nd licensing requirements may reflect that difference-
in degree of hazard, in transport, storage, processing and disposal. Reg-
ulatory standards based upon criteria will be different than those based
solely upon point of origin since no differentiation in degree of hazard
may be mad,e.
Options in implementation of criteria-based regulatory program—
o who shall apply criteria? generator? transporter? disposer?
o who incurs the expense of applying criteria?
o how often must waste be tested? Each load? Only when a
change in Stream occurs?
o what if cost of testing is prohibitive?
Inventory Methods
Inventory methods based on criteria system will vary from currently
practiced survey methodologies. How a question is asked and to whom is
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crucial. Questions usually are volume oriented and perhaps should be
weight oriented (weight of metals in solution versus gallons generated).
All possible sources of hazardous waste should be inventoried rather
than a selected SIC manufacturing population. Most surveys previously
conducted are industrial surveys - not hazardous waste surveys. The
results of the surveys determine the size, scope of program required,
whether or not environmental program coordination is required, type
and priority of regulation. Program levels should be given priority
on degree of hazard rather than by category of industry. Methods of
listing wastes on an inventory questionnaire may be by source, common
or generic name. The usage of uniform waste listing approaches is
crucial in the comparison of information gathered in a survey
compilation to information received through a manifest system.
Regulations
Currently, most existing state programs place primary responsibility and
regulatory control on .the disposal site operator. Frankly, this is the
weakest link in the decision-making chain. By the time a waste has
reached a disposal site all major economic decisions have been made.
The generator's, hauler's, storage facility operator's decisions
override those possible economic options which may be available to
the disposer. In effect, he has no economic recourse but to dispose
of the material in most cases. While this scheme places full weight of
responsibility upon a landfill operator, since his capability to respond
is limited, the hazardous waste management program - especially enforce-
ment-is weakened and possibly rendered ineffective. The new Federal law
clearly sets forth responsibilities of the generator, transporter, and
disposer. But regulations to be developed will determine degree of
responsibility with the expectation that the responsibilities of the
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generator will expand significantly. Alternatives also exist in
regulatory process in developing permits, providing for exemptions and
variances, degree and frequency of inspection. The alternatives break-
down into two categories - administrative and technical. In most cases
administrative procedures for review are addressed in already enacted
Federal and state laws. However, a degree of consistency in administrative
processes is hoped for, especially in those situations where several
environmental permits are required. For example, Washington State has
provided for a "one stop" permitting process and the Minnesota Environ-
mental Quality Council is reviewing such a proposal. The EPA should be
cognizant of this procedure in reviewing state's application for interim
and permanent authorization.
Technical: decide actual economic impact to applicant,especially if
best available technology is considered as a criteria in facility design
review and applied to monitoring, leachate collection, site selections,
emission control requirements. The purchasing of materials, system
design, service provisions will be affected and costs significantly
increased. Stress should be placed on performance rather than operating
standards. That is, a level of protection rather than specific method
of accomplishment should be considered in the permit review process.
Technical determinations can be applied to--
--definition determine scope of program, and level of enforcement
--permit requirements, length of time of permit
—financial responsibility and establishing degree of
liability of unanticipated damage
--manifest requirements
Time Frame
The scope of hazardous waste program is also dependent on time frame
for development and implementation. The time frame of Federal law
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appears to be 3 years. The time frame cf reference varies for
administrator, operator, generator. Administrator may determine -
18 months intervals - 3 year with review. However, hazardous waste
facility operator makes determination on 10 year intervals. An
administrative planner may think of two stage program - 18 months
develop regulatory program, 1 year for implementation, and 3 year review
schedule. All involved parties must recognize the impact on program plannina
of a start versus long time frame.
Interstate Compacts
The law provides for "establishment of such agencies, joint or otherwise,
as they may deem desirable for making effective agreements or compacts."
While compacts for air and water programs are contiguous, hazardous
waste management occurs in economic corridors which are not necessarily
contiguous or encompassed by geographic rec.ion. Therefore, compacts
between states which are not contiguous may be expected, especially in
the enforcement of a manifest program.
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The Role of 208 Regional Planning
Organizations in Solid Waste Management
by
Robert A. Colonna, President
Decision Systems, Inc.
When the Federal Water Pollution Control Act (FWPCA) was passed in
1972, Section 208 called for areawide water planning, and implementation
programs to carry out these plans. The objective of this section was to
provide adequate State and regional planning to protect the ground and
surface waters of this Nation.
The complexity of Lac: problem ib LhaL major metropolitan areas dis-
charge millions of tons of industrial and municipal wastes each year into
the ocean, inland waterways and on the land. Only some of these wastes
are discharged into sewers for primary and secondary treatment. The balance
is dumped, untreated, into these three sinks: the ocean, inland waterways,
and on the land. Even the wastes which reach treatment plants are only
regulated with respect to the water effluent; the solid portion, which con-
tains many potciitially hazardous materials, is disposed in many cases,
without adequate regulation.
Each year, this Nation generates 135 million tons of municipal
waste, 270 million tons of industrial wastes, and 40 million wot tons of
sewage sludge — and these quantities are growing every year. Approximately
907. of the municipal wastes, and over half of the industrial wastes and
sewage sludge are deposited on the land. If not disposed of properly,
leachate from these wastes reaches ground water which, at best, is left
discolored and odorous, and at worst, is rendered non-potable. Approxi-
mately 90 million gallons of leachate is generated nationally each year,
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an unknown portion of which readies ground water. Once ground water is
contaminated it is too costly to attempt to clean it up and it must be
abandoned as a drinking water supply. Alternatives may mean transporting
water great distances, also a costly remedy. Since 507= of the Nation
uses ground water for drinking, this is potentially a serious nationwide
problem, and one which cannot be ignored.
An implicit part of the 208 water planning and management program
is the development of a residual management plan which can be implemented.
Specifically, sewage sludge processing and disposal was to be covered by
Section 208 according to the legislative intent of the Act. However, since
many localities and regions currently combine sewage sludge and municipal
wastes (garbage and trash), and since, in the absence of pretreatment regu-
lations, many industrial wastes empty, untreated, into sewage treatment
systems, the residuals problem cannot easily be segmented.
Section 208 of the FWPCA defines residuals as any solid or semi-
solid waste m-iterlal vhich may result in ground or t,urfai_u wai_er contam-
ination if disposed of improperly on the land. As you can see, the de-
finition is very broad, and docs include mixed municipal wastes. Like
most laws, the language of 208 is broad in its scope and leaves to the
states and local government a narrowing of the definition according to
their priority needs.
A major question that has arisen in the progress of 208 is "what
is the role of existing local, regional, and State solid waste planning
agencies"? It is the intent of the 208 program to involve these agencies
as an integral part of the process. They have the solid waste or residuals
expertise, and in many cases have developed or are developing a residuals
plan. These plans contain the basic data and analysis for good decision
making, and if utilized, should accelerate the achievement of 208 goals.
It is the intent of EPA to insist that these agencies be used and not
ignored. Guidance to this effect has been given to all 208 agencies in
a series of ten regional seminars over the past six months.
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However, in spite of these efforts to include existing solid waste
management planning agencies and service companies, some may be overlooked
by the 208 agencies. In most cases this will he through an oversight —
not being aware of the work that is already being done to insure proper
solid waste disposal. All oi you who are a part of an existing solid
waste planning department, or a member of a local association of NSWMA
should find out from the Water Planning Division of EPA, the name and address
of the 208 agency in your area, and contact them directly with your infor-
mation concerning current solid waste management activities in your region.
Another difficulty is the variability in level of involvement at
the State level. In all cases, the Governor has the authority to desig-
nate regional 208 agencies. In regional areas which are not so designated
(and, in the extreme, this may be the entire State) a State agency, also
designated by the Governor, assumes the 208 planning and management
function. So some states have chosen to engage in an active role, while
others pass the responsibility (and the funds) to the regional agencies.
The operational system for dealing with residuals is in place, to
some extent, in every community. Private companies and government
agencies are collecting, processing, and disposing of municipal wastes
already. Many arc performing these tasks in an economical and environ-
mentally-sound manner. In the case of sewage sludge and industrial wastes,
there is less public visability, so, to date, only the most responsible
companies and agencies have been concerned with the environmental impacts
of its methods of waste disposal.
The 208 program is more than a planning program, which is a fact
that has escaped many in trying to understand the goals of the program.
It is the intention of the program to develop a residuals plan and imple-
ment it through "an appropriate management agency". Herein lies additional
opportunity for misinterpretation by the 208 agency. In many parts of the
country, regional or local management agencies already exist for residuals.
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Such management agencies might reside in a COG, a public works depart-
ment, a sanitary district, etc. In the case of private sector perfor-
mance of services, the' management agency might be the one that develops
the bid specification, and issues the contract for services. In any
event, 208 intends for there to be implementation of its plans, other-
wise the entire process will have been a waste of time and money.
Regional agencies which do not have management authority, will
need to form a new agency, with the political and financial backing of
the local governments in the region. Since bonding authority is fre-
quently required for capital-intensive solutions, it is important for
the management agency to have this authority. An example of how this
lias worked successfully is the Southeast Oakland County (Michigan)
Incinerator Authority. In this case, fourteen communities formed an auth-
ority to purchase, own, and operate an incinerator. Moreover, they agreed
to share cost and performance data on their waste collection systems in
an effort to work toward more efficient .systems. Some communities
performed waste collection themselves while others decided to contract
to private haulers; but all used the incinerator for volume reduction
and subsequent disposal.
If a cognizant management agency does not currently exist, it
would be appropriate for 208 agencies to begin the process of developing
a management agency early in the planning cycle since it will take some
time and political effort to develop such an institution, and the plan
can then be better tailored to meet the realistic authority and financial
capability of the management agency.
Finally, the latent information on the additional -monies available
in the 208 program is as follows: $137 million dollars will be available
to Regional Offices by the end of December. Some portion of this money
will be used to raise the federal share of existing grants from 75% to
100%. Additionally, some portion will go directly to states. Finally,
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a great deal of discretion will be exercised by regional offices on
how this money is spent. Therefore, the amount of new funds to be
spent on residuals will be up to each region, with some guidance
provided by EPA headquarters.
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THE ROLE OF THE PRIVATE SECTOR IN REGIONAL SOLID WASTE
MANAGEMENT PLANNING
Mary Ann Dean
Manager
Legislative Program
To date, there has been little participation by the
private solid waste management sector in regional solid waste manage-
ment planning. This is partially because legislative initiatives for
regional solid waste management olanning are just now getting
underway. While states such as Michigan, Missouri, California and
Florida provide for county plans, the recently enacted Federal
"Resource Conservation and Recovery Act of 1976" is the first require-
ment for states to consider comprehensive regional planning for solid
waste management, including hazardous waste management and resource
recovery.
Under the new Federal law, the U.S. Environmental Protection
Agency is required to publish guidelines by April 1977 for identifying
regional solid waste management areas. The States with the help of
municipal and local officials are responsible for designating regional
planning areas and agencies, as well as determining which functions will
be conducted on a state level and which functions will be conducted on
a regional or local level. The law specifically requests that con-
sideration be given to designating existing 208 wastewater treatment
agencies.
It is unclear, however, whether designation of existing
208 agencies will be for both planning and implementation. Under the
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Federal Water Pollution Control Act of 1972, there are two separate
designation processes, one for planning and one for implementation.
The majority of 208 planning agencies designated to date have been
general purpose units of government who have responsibilities in other
areas as well, such as in transportation and in housing and community
development. In general they do not have the authority necessary to
implement these plans. This authority is provided by the second
designation process for 208 wastewater treatment management agencies.
To be designated as a management agency an agency must have the
authority to directly or by contract design, construct, own and
operate new and existing facilities, incur indebtedness, and raise
revenues.
The new Federal "Resource Conservation and Recovery Act of 1976"
combines the designation process for both planning and implementation
r
without defining the criteria of either. The concern of the private
solid waste management industry is that while designation of existing
208 planning agencies may be appropriate for solid waste management
planning, designation of 208 management agencies may be very
inappropriate. Local or municipal wastewater treatment agencies
are likely to be designated as the implementation agencies. These
agencies are largely unfamiliar with solid waste management issues or
problems, or with the private sector in\olvement in this field.
Unlike the solid waste Industry which is predominantely serviced by
the private sector, municipal wastewater treatment facilities are
generally publically owned and operated.
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EPA's Office of Water Planning and Standards and Office of
Solid Waste recognized the low priority being given by the 208 agencies
to land disposal problems, particularly the problems of potential
migration of leachate into ground waters. In response the agencies
made a formal agreement to allocate both funds and technical expertise
to these problems. As mentioned earlier, EPA has conducted 10 regional
seminars this year to encourage the 208 planning agencies to become
aware of residual management planning, including solid waste, hazardous
waste and resource recovery planning. For the first time, many of
these 208 agencies began thinking about solid waste management planning.
EPA has also outlined a suggested minimum level of study by 208 agencies
for residual management. The agencies are asked to estimate landfill
capacity in the area, examine soil conditions, locate existing surface
and groundwater supplies. The agencies are also asked to determine
•«
if existing sites have adequate life and are in compliance with
regulatory policies, and if they are not, the agencies are asked to
include in their plan suggestions for new site locations. Clearly
the public and private solid waste management sector needs to become
involved in providing these agencies with the necessary input
to insure that all alternatives have been considered. The
Association and industry members have attended many of the
regional seminars in an attempt to become more familiar with the
agencies and their problems and to illustrate the concern of this
industry in addressing these problems. However, there are over
149 designated 208 planning agencies in various stages of their
planning process. Therefore it will require a major undertaking by
the solid waste management industry to develop a working relationship
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with each of these agencies in addition to any new agencies designated under
the "Resource Conservation and Recovery Act." I might add that this is only
the first stage of involvement. The Act clearly intends for these plans to
be implemented. Who implements, and how they are implemented will be equally
important and will shape the operational capability of the private solid
waste management industry in the future.
There are sev'eral ways for the private sector to become
involved. Most 208 agencies use advisory committees in developing their
plans. Membership on an advisory committee will be governed by their
Administrative Procedure Regulations. But clearly the first step is getting
involved and requesting it. The agencies also seek public involvement through
public hearings, meetings and newsletters. The Association on behalf of the
solid waste management industry has requested to be placed on the newsletter
mailing list by all 208 agencies, and in return will provide technical and
planning information to these agencies.
In addition to becoming involved in the planning process of
the existing 208 planning agencies, the private sector needs to become
actively involved in the implementation of the new Federal act. The new
Federal act specifically requires public participation in the development,
revision, implementation and enforcement of the regulations and enforcement
of the act. Federal guidelines are required to be designed to foster coop-
eration among Federal, State, and local governments and private industry.
.Agencies receiving Federal financial assistance are requested to consider
existing solid waste management services as well as facilities proposed for
construction. However, while the mechanisms have been outlined by the legis-
lation to allow for public participation, the private sector must take the
initiative in getting involved.
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Involvement needs to be on several levels, Federal, state,
regional and local. On the Federal level, private industry needs to be first
involved in providing input to EPA on factors to be considered in establishing
guidelines for identification of regional planning areas. These guidelines
are already being drafted and, will be promulgated next April. Information
is necessary on the size and location of appropriate areas for solid waste
management areas, including resource recovery and hazardous waste management,
the volume of solid waste which should be included, and the means of coordi-
nating regional planning with other related planning in the area and with
the overall state plan. These guidelines must be flexible if they are to
deal effectively with the existing services and facilities. EPA will recommend
usage of existing 208 unless they receive information illustrating where an
existing 208 is not appropriate.
The second area of involvement is on the state level. The
state, in cooperation with local governments will not only designate tlie areas
and agencies, but also wilL identify what areas of solid waste management will
be handled on a state level and what will be done on a regional or local level.
The process is designed to give maximum flexibility to state and local govern-
ments. Therefore, the number of regional and local planning agencies and the
level of planning delegated to each agency will vary from state to state.
Several states such as Alabama, Tennessee, Arkansas and Indiana have already
passed legislation authorizing local authorities to expand their jurisdiction
.to include solid waste. Alabama, for example, recently passed legislation
authorizing sewer districts to provide solid waste collection and disposal
systems. The relationship between local and county plans with the new overall
regional plans to be developed will have to be defined state by state. California,
has been the first to my knowledge in defining this relationship.
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The State Solid Waste Management Board in California has
already passed a resolution stating that the state approved county solid
waste management plans will be recognized and adoped as the solid waste
management component of the 208 plans. t
Finally, on a local and county level industry will have to
continue its involvement in the planning process, while a regional level
industry will need to become involved in providing information to be utilized
in the formulation of the plans, such as demographic data, statistical data
on the amounts of waste generated and other information necessary to determine
what functions can best be handled on the regional level.
In conclusion, regional planning has expanded the areas in
which industry must become involved. Participation in each area will vary
according to the agency involved, states and regional and local agencies
will develop individual schedules and procedures for preparing plans and
participating in the formulation of those plans. There are potential benefits
of regional planning, given the proper guidance, assistance and support.
**
Whether the private solid waste management industry shares in those benefits
will depend on their ability to become involved in both the planning and
implementation process.
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LINERS - VIABLE OPTIONS AND THEIR APPLICATIONS
Henry E. Haxo, Jr.
Matrecon, Inc.
Oakland, Ca.
We are all well aware of the vast quantities of wastes that are discarded by
our highly technological and urban society. In spite of the many efforts to de-
these wastes
velop new methods of disposing of/or utilizing them f we can expect that the
storage and disposal of wastes on land will continue to rise for many years. At
the same time, we can also expect an increasing potential for pollution of the
ground and surface water by these wastes or by leachate being generated in the
wastes, percolating through, and carrying with it dissolved and suspended biologi-
cal and chemical products.
Proper selection, design, construction, and operation of waste storage and
disposal sites can minimize pollution. However, the availability of acceptable
disposal sites is decreasing because of environmental and economic impact. Fur-
thermore, there are geographic areas of high humidity and rainfall or high water
tables which pose special problems.
The concept of lining a disposal site with impervious barriers is being con-
sidered as a means of controlling leachate from wastes and preventing it from en-
tering the ground water system. A wide variety of impervious materials has been
used to line ponds, lagoons, canals, and small lakes. Materials such as these
might also be used to control leachate and hazardous wastes. However, little is
widely known about the behavior of these materials on prolonged exposure to land-
fill leachate and to other hazardous wastes.
In this paper, we discuss the various materials which might be used as im-
permeable barriers, with particular emphasis on those potentially useful in lin-
ing sanitary landfills. We report on progress in two current engineering re-
search projects sponsored bv EPA to assess various liner materials exposed to
landfill leachate and to hazardous wastes.
LINING ft SANITARY LANDFILL
The sanitary landfill is an acceptable and recommended method of disposing
of solid wastes when sound engineering principles are followed in site selection,
design, construction, and day-to-day operations are highly controlled to minim-
ize odor, vector attraction, fire hazards, blowing of paper, and maintenance of
good appearance.
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Nonetheless, leachate containing a wide range of chemical and organic
constituents, such as shown in Table I, can be generated in a landfill by water
entering the fill, dissolving salts and products of the decomposition of the
refuse. Such leachates can contaminate and pollute the ground water. It is
estimated that more than 60% of the landfills in the United States will produce
leachate during their lifetimes.
TABLE I - RANGE OF COMPOSITION OF 1'YPICAL LEACHATES FROM SANITARY LANDFILLS
Constituent Concentration
Range*
Iron 200 - 1700
Zinc 1 - 135
Phosphate 5 - 130
Sulfate 25 - 500
Chloride 100 - 2400
Sodium 100 - 3800
Nitrogen 20 - 500
Hardness (as CaCO ) 200 - 5250
COD 100 - 51,000
Total residue 1000 - 45,000
Nickel 0.01 - 0.8
Copper 0.10 - 9.0
pH ' 4.00-8.5
* All values except that for PH are in mg/1.
To prevent the seepage of leachate, with its high concentration of
pollutants, into the surface and ground water, landfills can be isolated from the
ground by placing an impervious layer between the landfill and the ground.
The concept of using an impervious barrier as a liner for a landfill is
basically simple as is illustrated in Figure 1. An impervious material is placed
upon a properly prepared surface that is graded for drainage. The amount of sur-
face preparation depends on the specific type of liner material being Installed
and on the soil base on which the liner is being placed. This surface must be
free of stumps and rocks and should be compacted. The liner can be several feet
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LL.
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in thickness or only a fraction of an inch; it can be compacted native fine-
grain soil, clay, asphaltic concrete, polymeric membrane, or other artificial
barrier. Porous soil or sand should be placed on the liner through which leach-
ate can flow and on which refuse can be compacted in the manner normally done in
sanitary landfills. Leachate percolating through the refuse will be intercep-
ted by the barrier and drain through the porous layer. It can be collected for
ultimate disposal in a sanitary sewer system or a leachate treatment system, or
be recycled through a landfill to hasten stabilization of the fill.
It is these liners which we will discuss in this paper. Let us consider
first the requirement of a liner and the environment in which it must exist.
ENVIRONMENT OF A LINER IN A LANDFILL
The primary purpose and function of a liner is to prevent the passage of
pollutants, such as leachate, for extended periods of time. In the case of a
landfill, it may mean decades until the fill has stabilized and the potential
for leachate generation has fallen to safe limits. To fulfill its function, a
liner must be impermeable to water and the contaminants and must maintain its
structural integrity.
Liner failures vary with the type of material. A liner can crack, be punc-
tured, fail at a seam or interact with the medium being confined. The useful-
ness of a liner depends upon the material and the environment in which it is ex-
pected to operate.
Some of the environmental conditions at the bottom of a landfill should have
little or no adverse effect on a given material, while other conditions may be
quite deleterious. Conditions which exist at the bottom of a landfill that prob-
ably affect the service life of a liner are:
1) The liner is placed on a prepared surface, which has been
graded to allow drainage, compacted, and presumably free of
rocks, stumps, etc., but which may settle to cause breaking or
cracking of hard material. A brittle or weak material would fail.
2) Anaerobic condition with no oxygen to cause oxidation.
3) No light which normally degrades many organic and poly-
meric materials.
4) Generally wet-humid conditions, particularly if leachate
is being generated regularly, which could result in the leaching
of ingredients from a liner.
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5) Cool temperatures of 40 - 70 F normally, although higher
temperatures are generated within the fill when aerobic de-
composition takes place.
6) Generally low pH from acidic leachate.
7) High concentration of ions in the leachate which, in the
case of clay, may ion-exchange and flocculate the clay and
thus increase permeability.
8) Considerable dissolved organic constituents in the leach-
ate which may degrade some of the liners of organic materials.
9) Only modest head pressure, since drainage above the liner
is designed to take place continually through the porous soil
placed on top of the liner.
The effects of these environmental conditions will differ on the various bar-
rier materials. However, it appears at present that mechanical failure during in-
stallation or during operation of the fill due to settling of the soil may be the
most significant source of failure of a liner.
POTENTIAL MATERIALS FOR LINING SANITARY LANDFILLS
Typical of the wide range of materials which have been or are being used as
barriers to the seepage of water and hazardous toxic wastes in holding ponds, pits,
lagoons, canals, reservoirs, etc., are those listed in Table II. Selection of lin-
er materials for a specific job depends upon the type of fluid or waste being con-
fined, the types of materials which can perform for the lifetime needed and econom-
ics. Often several materials can be used and the choice then becomes one of eco-
nomics and the length of time which the liner should function. At times it may be
desirable to use combinations of materials.
Some of the earliest man-made lining materials are those based upon compacted
soils, asphalt, and portland cement. These are admixed materials which are gener-
ally formed or mixed-in-place at the site. Several of the more well known admixed
materials are discussed below:
1. Native fine-grain soil,when available nearby, is imported
to'tne site and compacted as a liner. Permeabilities of 10
cm/sec, can be achieved. This is often used for containing
water.
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TflBLE II. POTENTIAL MATERIALS FOR LIKING SANITARY LANDFILLS^
Compacted native fine-grain soils.
Bentonite and other clay sealants.
- Bentonite - polymer sealants.
Asphaltic compositions
- Asphalt concrete.
- Hydraulic asphalt concrete.
- Preformed asphalt panels laid on concrete surfaces.
- Catalytically-blown asphalt sprayed on soil.
- Emulsified asphalt sprayed on soil or on fabric matting.
- Soil asphalt.
- Asphalt seals.
Portland cement compositions
- Concrete with seals.
- Soil-cement with seals.
Soil sealants
- Chemical
- Lime
- Rubber and plastic latexes.
- Penetrating polymeric emulsions.
Liquid rubbers sprayed
- Rubber and plastic latexes.
- Polyurethanes.
Synthetic polymeric membranes
- Butyl rubber -
- ^lasticized polyolefin.
- Lthylene propylene rubber (EPDM).
- Chlorosulfonated polyethylene (Hypalon).
- Chlorinated polyethylene (CPE).
- Polyvinyl chloride (PVC).
- Polyethylene (PE).
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2) Bentonite and treated bentonite are well known in the pe-
troleum industry and also in the sealing of ponds and lakes.
These are expansive clays and can be mixed in or deposited on
permeable soils to form adequate seals for water. Water perm-
eabilities of 10 cm/sec can be achieved with these materials. How-
ever, with saline waters these materials will eventually lose impermeability.
3) Conventional asphalt concrete, hot-mixed and hot-laid, is
widely used for paving and is readily available. Contractors
are experienced in its placement and have the necessary equip-
ment. It presents a hard surface, resistant to traffic and
impact forces, and as resistant to acids and to aging, espec-
ially in the absence of light and air. As it is designed to have
a voids content of about 5% , it is not completely impervious •
therefore, a. surface treatment to seal t>-e wot^s ">?« *•«>.
4) Hydraulic asphalt concrete, also hot-mixed and hot-laid,
is especially designed to be impervious. Low permeability
is achieved by controlling the gradation of the aggregate and
the asphalt content to obtain a virtually voidless structure
after compaction. Its other properties are similar to those
of asphalt concrete. Hydraulic asphalt concrete is mixed, laid,
and compacted with the same equipment used for conventional as-
phalt concrete, but is more difficult to handle.
5) Soil-cement is made by mixing the in-place soil with port-
land cement and water, and compacting the mixture. As the port-
land cement hydrates, the mixture becomes a hard, low-strength
Portland cement concrete. Soil-cement is sometimes used as a
surface for pavements with low- traffic volume, and is extensiv-
ely used for the lower layers of pavements, where it is called
"cement-treated base." Strong soil-cement can be constructed
with many types of soil, but permeability varies with the nat-
ure of the soil; the more granular the soil, the higher the
permeability. With fine-grained soils, soil-cements with perm-
eability coefficients of about 10 cm/sec are achievable. In
practice, surface sealants are often applied to the soil-cement
to obtain a more waterproof structure. Aging characteristics
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of soil-cement are good, especially under conditions where wet-
dry and freeze-thaw cycling are minimal. Some degradation of
the cement can be expected in an acid environment.
6) Soil asphalt of mixed-in-place asphalt surfacing is made
by mixing a liquid asphalt with the in-place soil or with im-
ported aggregate. It is widely used for low-cost pavements
for low-volume traffic. Permeability characteristics can be
controlled by the amount and type of asphalt added. Soil as-
phalt is more flexible and resistant to cracking than asphalt
concrete or soil-cement, and has good aging characteristics in
the absence of light.
7 ) Catalytically-blown asphalt membranes have been used ex-
tensively as linings for canals and reservoirs and to seal off
layers of expansive soils under pavements. This type of as-
phalt is produced by air-blowing in the presence of a catalyst
(phosphorous pentoxide or ferric chloride), which produces an
asphalt which has a high softening point, yet remains flexible
at low temperatures. Membranes are applied to compacted, smooth
soil surfaces by spraying the hot (200 to 220 C) asphalt in two
successive applications to insure a continuous film free of pin-
holes and holidays. Aging resistance is good when protected
from light. It is usually covered with a protective layer of
soil to prevent damage by traffic and deterioration by light.
8) Bituminous seals of asphalt emulsion can be applied on soil
at temperatures above freezing. They form continuous films of
asphalt after breaking of the emulsion and evaporation of the
water. The films are less tough and have lower softening points
than films of hot-applied, catalytically-blown asphalt. However,
toughness and dimensional stability can be achieved by spraying
asphalt emulsions onto a supporting fabric. Fabrics of woven
jute, woven or nonwoven glass fiber, and nonwoven synthetic fi-
bers have been used with various anionic or cationic asphalt
emulsions to form linings for ponds and canals.
Polymeric membranes are assuming increased importance as liner materials be-
cause of their very low permeability to many fluids and water. These membranes
are made in the plastics and rubber industry and are manufactured in the form of
sheeting of 10 to 125 mils thickness and widths up to 20 feet. Compounds based
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on the same polymers can vary considerably among liner manufacturers, depending
upon the grade and price. They are made both with and without fabric support.
Generally, the sheeting is made by calendering of two plies and fabric, if de-
sired. The two plies are used to avoid pinholes through the sheeting. Both
vulcanized and nonvulcanized or thermoplastic polymers are used. The liners
are brought to the site in the form of preassembled panels which are then
seamed in the field. Field seaming is one of the major problem areas in the
use of polymeric liners. Heat sealing, cementing and solvent welding are used
both in the factory and in field seaming. Vulcanized sheetings have presented
the most problems, particularly on the field. Cold-curing adhesives usually
are required to make the seams.
The polymers which are being used for the manufacture of liners, or show
particular promise, are discussed below:
l) Butyl rubber is a copolymer of isobutylene and isoprene,
usually supplied as a vulcanized compound. This rubber is
well known for its impermeability, both to air and water. A
butyl rubber sheeting was the first polymeric material to be
used for pond lining and an installed liner has shown no deg-
radation after more than 20 years of service.
2) Chlorinated polyethylene (CPE)is a thermoplastic material
produced by the chlorination of polyethylene. As a completely
saturated material, it is not susceptible to ozone and has
good crack and low temperature resistance.
3) Chlorosulfonated polyethylene is a saturated rubber
having excellent weathering, ozone, and sunlight resistance.
When vulcanized, it is highly resistant to a wide range of
chemicals, but is generally supplied in an unvulcanized form
which swells in oil and some chemicals.
4) Elasticized polyolefin is a recently developed material
which is furnished in a thermoplastic form. It has excel-
lent chemical and weathering resistance.
5) Ethylene propylene rubber is a terpolymer of ethylene
propylene with a minor amount of diolefin to allow it to be
vulcanized. It has excellent weathering and ozone resistance
and is sometimes used in blends with butyl.
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6) Polychloroprene, or neoprene.is supplied as a vulcanized
rubber compound. It features oil and chemical resistance;
however, it is relatively expensive and is usually used in
special applications.
7) Polyethylene is well known as a film in construction and
has high chemical and weather resistance if supplied in black
compounds. It is easy to puncture during installation.
8) Polyvinyl chloride is the most widely used polymeric liner.
The PVC compound is thermoplastic, containing 30 to 50% plasti-
cizer and about 2% stabilizer. Because of plasticizer volatil-
ity, these materials are generally covered to avoid loss of
plasticizer and to furnish protection from light.
CURRENT RESEARCH IN THE EVALUATION OF LINERS
The Municipal Environmental Research Laboratory of EPA is sponsoring two en-
gineering research projects which are being conducted by our laboratories with
the assistance of the Sanitary Engineering Research Laboratory of the University
of California, Berkeley:
• Evaluation of liners for sanitary landfills.
• Evaluation of liners for impounding hazardous wastes.
The overall objectives of these studies are to determine the present state
of liner technology as it might be applied on a practical scale 'to confining
wastes. Specifically, we are evaluating a variety of liner materials, exposed
over a 3 to 3>j year period, to leachate generated in municipal refuse, and to
a range of hazardous wastes. These projects are now scheduled for completion
in mid-1978, at which time we expect to be able to make an assessment of the
performance of the different liner materials and to estimate their service
lives, based upon the changes in their properties and permeabilities during
the exposure period. Ultimately, we expect to be able to write specifications
for liner materials based upon performance.
We shall concentrate our discussion on the first of these projects, liners
for sanitary landfills; however, much that is said about this project is also
pertinent to the second.
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9 ) To determine the composition of the shredded refuse from
a blend of grab samples taken during the loading of the cells.
10) After the refuse in the cells is saturated, i.e. brought
to "field capacity", to generate leachate by adding one inch
of tap water every two weeks (26 inches per year) and allow
leachate to pond on the liner at a depth of about one foot.
11) To monitor the simulated landfills, characterizing the
leachate during exposure period to insure proper conditions
exist in the refuse.
Experimental Program -
To simulate the actual conditions which exist at the bottom of a landfill,
24 generators were constructed, as shown in Figure 2. Each consists of a 10-
foot steel pipe, 2-feet in diameter, mounted on a concrete base in which a lin-
er approximately 2-feet in diameter is sealed in position with epoxy. Two spec-
imens of each of the 12 primary liner materials were mounted; one group of 12 to
be exposed for one year and the second group for two years. Draining can be per-
formed above and below the liner to measure the permeability of the liner. The
pipes were lined with a polyethylene sleeve and the interiors of the concrete
bases were coated with a chemically-resistant epoxy resin. The pipe was sealed
to the base with a neoprene sponge gasket and mastic seal to insure airtightness.
Each pipe was filled with 24 cubic feet of shredded municipal refuse com-
pacted to 1240 pounds per cubic yard at a water content of 30%; a soil cover of
1.75 feet was then placed on the refuse, followed by three inches of drain rock.
This design simulates approximately one lift of refuse in a sanitary landfill.
For our tests, we selected 12 primary liner materials, six of them admixed
materials:
Paving asphalt concrete
Hydraulic asphalt concrete
Soil cement
Soil asphalt
Bituminous seal
Emulsion asphalt on fabric
and six polymeric liner membranes:
Polyethylene
Polyvinyl chloride
Butyl rubber
Chlorosulfonated polyethylene
(nylon scrim reinforced)
Ethylene propylene rubber
Chlorinated polyethylene.
Elasticized polyolefin had not been developed when the selection was made.
Therefore, it was not included in the initial program.
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LINERS FOR LANDFILLS -
General Approach -
Considering the wide diversity in the types of materials which are candi-
dates for lining landfills and the urgent need for information regarding their
performance and durability in a landfill environment, our overall plan has
been:
1^ To expose a variety of representative liner materials to
typical landfill leachate under conditions simulating real-
life and measuring the physical properties as a function of
exposure time, for a period of 3 to 3>j years.
2) To select for exposure testing 12 types of liner materials
from among those which have been successfully used in lining
pits, ponds, lagoons, canals, etc., to prevent seepage of wa-
ter or various wastes and which appear suitable for lining
sanitary landfills.
3) To accelerate the possible effects of the leachate by se-
lecting thinner liners than normally used in the field.
4) To expose liner specimens to leachate on a pilot scale
which simulates, as closely as possible, those conditions that
a liner would encounter at the bottom of a real landfill.
5l To expose specimens of sufficient size so that physical
tests can be made to measure the effects of exposure to leach-
ate and, if appropriate, a typical seam can be incorporated
for testing.
6) To subject the liner specimens to appropriate tests for
the specific type of liner. Properties would be measured
which could be expected to reflect on the performance of the
respective liners in sanitary landfills.
7) To seal the liner specimens in individual simulated land-
fills so that whatever seepage might come through can be col-
lected and tested. This cell and generator would perform as
a large permeameter.
8) To create equal conditions in all simulated fills, so that
valid comparison between liners can be made.
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iHRLDDED REFU6E
COMPACTED TO fl PT.
THICKNESS
CONCRETE
IEACHATE DRAIN FROM REFUSE*
TO COLLECTION BA(j
0
0
-\
DRAIN ROCK V THICI"
• 50IL COVER
iVVFT. THICK
• POLYETHYLENE LINER
- REFUSE COLUYSN-
4PIRAL-WELD PIPE,
Z+" DIA. * 10 FT. HIQH
-MASTIC 6EAL
5AND
LINEK •SPECIMEN
-CA'iT EPOXY RESIN RINQ
QRAVEL
LEACHATE. DRAIN THEU LINER
TO COLLECTION BA
-------
Soils and clays were specifically excluded by EPA from this study as they
were included in other investigations, such as that being carried on by Dr. Wal-
lace Fuller at the University of Arizona.
After loading the cells with ground refuse, they were brought to field ca-
pacity by incremental additions of tap water over a month. Afterwards, two gal-
lons of water were added biweekly to equal 26 inches per year of water entering
the fill. One foot of leachate was allowed to pond on the liners.
The 24 cells operated satisfactorily, yielding consistent leachate among
the generators. The leachate compositions were measured on a regular basis.
They showed a relatively high amount of organic acids, particularly butyric acid,
a chemical which swells many rubbers.
During the first few days after the cells were loaded there was a slight
rise in temperature after which the temperature fell to ambient and remained
at that temperature, approximately 15 to 20 C. During this time conditions in
the cell went from aerobic to anaerobic.
The tests which were selected for the polymeric membrane liners and the ad-
mixed liners are shown in Tables III and IV. These tests were performed on both
unexposed and exposed specimens.
The tests used in the monitoring of the refuse and leachate are given in
Table V. Most of these were performed on a monthly basis, although the tests
for the individual organic acids were performed on a quarterly basis.
Results of one year's exposure to leachate -
After one year of exposure to leachate, the first group of 12 liners was
recovered from the leachate generators and their properties measured. Overall,
the effect of this exposure upon the physical properties was minor. There were
small losses in the tensile strengths of all liners, except polyethylene and
EPDM, neither of which lost strength. The elongation at break increased in all
cases; the modulus, or stiffness, generally dropped, except in the case of poly-
ethylene, ethylene propylene and butyl rubbers, where it remained essentially
the same. In all cases, the liners softened. The tear strength and puncture
resistance increased, undoubtedly due to the increase in elongation. In seam
strength there were some major losses; however, those seams which had been
heat sealing retained their strengths best.
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TABLE III. TESTING OF POLYMERIC MEMBRANE LINERS
Water vapor permeability, ASTM D96, procedure BW.
Thickness and weight per square foot.
Tensile strength and elongation at break, ASTM D412.
Hardness, ASTM D2240.
Tear strength, ASTM D624, Die C.
Water absorption or extraction at RT and 70 C, ASTM D570.
Splice strength, in peel and in sheer, ASTM 413.
Puncture resistance - Fed. Test Method Std. No. 101B, Method 2065.
Density, ash, and extractables.
TABLE IV. TESTING OF ADMIXED LINER MATERIALS
Permeability Back pressure permeameter
Density and voids ASTM D1184 and D2041
Water swell Calif. Div. of Highways 305
Compressive strength ASTM D1074
Sliding plate viscosity of asphalts Calif. Div. of Highways 348
Microductility of asphalts Calif. Div. of Highways 349
TABLE V. TESTING OF REFUSE AND LEACHATE DURING MONITORING
Temperature
Amount of leachate
Total solids
Volatile solids
pH
Chemical oxygen demand (COD)
Total volatile acids (as acetic acid)
Individual organic acids
Acetic
Propionic
Isobutyric
Butyric
Isovaleric
Valeric
Caproic
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As for the permeability of the liners, during the first year none of the
polymeric membranes allowed leachate to pass. There was, however, leakage
through the soil asphalt and asphalt concrete liners. The epoxy seal around
the hydraulic asphalt disintegrated, allowing the leachate to bypass the liner.
As the absorption of leachate by the liner material is an indication of
its permeability, the leachate absorption of each liner was determined and the
results are shown in Table VI.
TABLE VI. WATER AND LEACHATE ABSORPTION BY POLYMERIC LINERS
Data in percent absorbed by weight
Polymeric Liner
Butyl rubber
Chlorinated PE
Chlorosulfonated PE
Ethylene propylene rubber
Neoprene
Polybutylene
Polyethylene
Polypropylene
Polyvinyl chloride
Water
1 year
1.60
13.10
17.40
1.40
22.7
0.25
0.20
0.28
1.85
Leachate
1 year
1.78
9.0
20.0
5.95
8.73
0.33
0.25
0.40
6.72
The column on the right is the absorption in leachate the first year for the
same material. As can be seen, there is not a one-to-one relationship between
the water and leachate absorption. This reflects the dissolved solids content of
the leachate, both inorganic and organic. In the case of the materials which are
highly hydrocarbon in character, the swelling of both in water or leachate is very
similar. However, in the case of the chlorinated materials, there is a substan-
tial amount of water absorption, particularly in the case of the chlorinated poly-
ethylene, Chlorosulfonated polyethylene and neoprene. The PVC had rather low ab-
sorption in water but, in leachate, the absorption may be significant.
In view of the relatively small changes in the liner materials which occurred
during the first year of exposure, the EPA has increased the total exposure time
for the remaining specimens from two years to about three and one-half years. Cer-
tainly two years would be insufficient to establish long-term trends as to the
service life of these liners.
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LINERS FOR CONTAINING HAZARDOUS WASTES
Our second project deals with the evaluation of liners exposed to nonradio-
active hazardous wastes. As in the case of leachate from landfills, the impound-
ment of the hazardous wastes on land can also present the potential for pollution
of ground and surface water. Barriers, such as membrane liners, have been used
for this purpose for approximately 25 years. However, information as to relative
performance and service lives of various liners in highly characterized hazardous
wastes is meager.
Our general approach was:
1) To expose at least 12 different liners in six or more wastes,
under conditions which simulate real-life, and determine their
properties as a function of time.
2) To select liner materials which are, or potentially could
be, used for lining ponds containing hazardous wastes.
3) To design and construct exposure cells which would simu-
late the condition under which the liner would exist in a pond.
4) To select a range of hazardous wastes of various types
which would be encountered in industry.
5) To highly characterize these wastes so that the liner be-
havior can be predicted for confining actual wastes in a given
installation.
The design of the exposure cell for this study is shown in Figure 3. It ii5
made of sheet steel coated on the interior with a chemically-resistant epoxy res-
in . It features:
1) Specimens of one square foot area, with field type seam.
2) A depth of waste of one foot.
3) It can be used for liners of various thicknesses.
The materials which were selected for this project are shown in Table VII,
and represent a broader group than were used in the landfill project. Bentonite
and fine-grain soil are included. As for the polymeric materials, we included
the same types of materials as were used in the sanitary landfill project, and
added three additional, (1) neoprene, (2) an elasticized polyolefin, and (3) an
experimental polyester film, all of which feature oil resistance.
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H 0<
01
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as
(1) -H
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1)
n a
w *
U4
-------
TABLE VII. LINER MATERIALS FOR HAZARDOUS WASTES
Thickness
SOIL AND ADMIXED MATERIALS in inches
Asphalt emulsion on nonwoven fabric 0.3
Compacted native fine-grain soil (from Mare Island. California) 12.0
Hydraulic asphalt concrete 2.5
Modified bentonite and sand 5.0
Soil-cement with seal 4.5
Thickness
POLYMERIC MEMBRANES in mils
Butyl rubber-reinforced 34
Chlorinated polyethylene (CPE) 32
Chlorosulfonated polyethylene - reinforced 34
Elasticized polyolefin 25
Ethylene propylene rubber (EPDM) 50
Polychloroprene (neoprene) - reinforced 32
Polyester (experimental) 7
Polyvinyl chloride (PVC) 30
The six types of hazardous wastes selected for use in this project are:
- Acidic wastes
- Alkaline wastes
- Pesticide wastes
- Oil refinery tank bottom wastes
- Lead wastes from gasoline tanks
- A cyclic hydrocarbon waste
So that the length of exposure time would be practical, we made the final se-
lection of combinations of liners and wastes after we had performed a series of
preliminary bench tests of liners in the various wastes. We did not select as-
phaltic liner materials for confining oily wastes, nor did we use clays to con-
fine briney and acidic wastes. Where a polymeric liner swelled badly in aromatic
waste, we deleted that combination.
These exposures have been underway for about 10 months. At 12 months the
cells will--be dismantled and the liners recovered and tested.
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In addition to the primary liners, we have:
1) Suspended additional small specimens of liners in the
wastes.
2) Lined 12 small tubs with various membrane liners and
filled them with hazardous wastes for exposure to the
weather.
3) Mounted a variety of liner specimens on a rack for
outdoor exposure.
FIELD EXPERIENCE IN THE USE OF LINERS FOR WASTE DISPOSAL SITES
The experimental work which has been described is on a laboratory or, at
best, pilot scale only. We have attempted to simulate the actual conditions en-
countered in full scale service but we recognize the many limitations of the ex-
posure conditions compared with the complexity and diversity of actual field dis-
posal sites. Each waste disposal or storage installation has its own unique
characteristics as to the materials being confined, the geology of the site, the
weather, etc.
The ultimate functioning of a liner in a given landfill will depend upon
proper site selection, design of the disposal installation, and proper construc-
tion and operation of the disposal site. Of particular importance is the con-
struction and field seaming when membrane liners are used. We start with highly
impermeable materials which, in order to function properly, should be placed
intact and with impermeable seams.
There is considerable experience in the use of liners for impounding water,
industrial fluids, and wastes in the chemical, petroleum, and metals industries.
Their use in lining sanitary landfills is recent and field experience is very
limited. A few experimental installations are about 10 years old, but the first
full-scale lined sanitary landfill is only five years old. There are now several
landfills lined with asphalt concrete and bentonite clay and three with polyvinyl
chloride. A butyl rubber liner has been used to line a disposal site for incine-
rator residue; chlorosulfonated polyethylene and chlorinated polyethylene liners
have been used in two small pilot landfills. Polymeric liners are presently
being considered for a number of new installations.
CONCLUSIONS
Lining land waste storage and disposal sites shows great promise of allevi-
ating and, hopefully, solving potential environmental problems of ground water
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pollution arising from disposal of solid and liquid wastes on the land. The con-
cept of using impervious liners to isolate and control leachate from solid wastes
appears to be feasible and is now being put into practice. There is a wide r
-------
THE IMPORTANCE OF SOIL ATTENUATION FOR LEACHATE CONTROL1
Wallace H. Fuller
Soils, Water and Engineering
The University of Arizona
Tucson, AZ 85721
INTRODUCTION
Almost all of man's waste now ends up on land. In fact, reliable
estimates place the amount that reaches the soil at about 90 percent, U.S.
tPA (1973},Hershaft (1972). Air and streams are only transport systems to
the soil, and dumping in the ocean has become very unpopular, even to the
extent of enactment of legislation prohibiting such action, U.S. Congress
(1972). The soil, thus, stands between life and lifelessness, not only in
food production but in biodigestion of waste, destruction of disease, and
retention of hazardous pollutants. It is a unique body. It is this unique-
ness which attracts our attention today. It is this uniqueness that has
protected us in the past from the polluting hazards of our wastes, which now
is threatened by point-source overburden of today's wastes.
By understanding how the chemical, physical and biological character-
istics of the soil and geologic material interact with wastes, we can begin
to develop practical management metnods for safe disposal, Fuller, et al. (1976).
The soil must now be considered for its role as a waste treatment/
utilization system, Figure 1. The economic shift with time will be from soil
as a treatment to soil as a utilization system. This shift, of course, will
not be sufficient to relieve the soil from the burden of waste disposal. Yet
certain constituents (such as paper, landscaping trash, food residues and
other natural organics) will be utilized for soil building and not merely
This research is supported in part by the U.S. Environmental Protection Agency,
SHWRD, Cincinnati, OH.
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referred to disposal. Further, a certain limited proportion of solid waste
can go into relief for energy sources as methane, Figure 2. Yet there is
waste (sludge), even in this system, that will require disposal on land (or
soil).
The soil must be regarded as a permanent resting place for all poten-
tially hazardous pollutants. The shift in thinking here is from classic soil
science for food production where plant nutrients are stored in the soil in an
"available", temporary or transient form (cation and anion exchange) to per-
manently fixed forms.
OBJECTIVE
Management of wastes to minimize their potential for long-range
pollution requires the manipulation of the components of disposal habitats
based on a thorough knowledge of the way these components interact toward
element migration and attenuation. This is the theme or objective of the
presentation today.
MAIN COMPONENTS OF DISPOSAL HABITATS
To understand what keeps potentially hazardous pollutants from
migrating into underground water sources and other locations where they
might enter the food chain, there are 3 systems which require examination
**r
and Study. They are the 3 main components of waste habitats:
1) the porous medium through which the constituent is being trans-
ported,
2) the solution carrying the pollution constituent, and
3) the constituent itself, i.e. the soluble element involved.
The characteristics of each component markedly influences attenu-
ation in soils. The characteristics of each component that have been found
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to influence migration and attenuation will be discussed separately.
The porous medium or soil — Some prominent physical soil factors in attenu-
ation are listed in Table 1. Texture refers to particle size distribution and
therefore represents gravel, sand, silt, and clay. Sand is found to be negatively
correlated to attenuation and clay positively. Sands and gravels retain solubilized
polluting constituents very poorly to not at all. Structure refers to arrange-
ment of soil particles and controls rate of solution flow through the soil,
water-holding capacity, solution flow rate, and may not be favorable if too
stable. For example, Molokai is highly structured even though it is a clay.
It most often acts like a sand. Solutions pass through so rapidly, the polluting
constituents may not diffuse into the clay and have contact time sufficient to
react to attain maximum attenuation.
Stratification defines the layering of soil and geologic material into
horizontal lenses of sand, silt, and clay, or gravel. Flux is a term better
described as rate of low through a porous medium. Compaction defines the
density. A compact soil may or may not favor attenuation depending on its extent.
Excessive compaction may perch water and prevent necessary flow downward and may
encourage lateral movement or seepage to the surface just as will cementation
layers. Wetting and drying influences the migration potential of pollutants
both favorably and unfavorably; for example, dehydration (a) favors retention
of constituents in the leachate by lowering the solubility as a result of
precipitation while at the same time (b) opens the soil for more rapid downward
migration through the shrinking and cracking processes. Rehydration again puts
some of the constituents back into solution but also closes the cracks. The
overall effect of wetting and drying of disposal materials and particularly
landfill leachates, however, is believed (from our experiences with soils)
to favor Tetention of pollutants in place. Specific research on this
factor for wasite leachates is yet in its infancy.
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Some prominent factors in attenuation according to Fuller (1976),
Fuller and Korte (1975), and Korte, et al. (1975), relate to chemical charac-
teristics of soils, Table 2.. They may be grouped into the three broad areas;
(a) surface area and clay content, (b) lime and pH (or acidity and alkalinity)
and (c) content of the hydrous oxides of Fe, Al, and Mn. Attenuation in soils
has been positively correlated with soil surface area and clay content, and
is negatively correlated with sand. The more alkaline soil pH values favor
precipitation of most heavy and trace elements and therefore attenuation.
Lime favors the development of a less acid soil and more alkaline pH soil
habitat. The abundance of hydrous oxides in soils also favors attenuation,
particularly Fe and Mn. How practical it is to alter the hydrous oxide
content in soils remains to be demonstrated.
Leachate Components -- Prominent leachate characteristics affecting
attenuation, according to our ongoing research, Table 3, include the concen-
tration of (a) organic constituents (TOC), (b) soluble salts, (c) acidity and
alkalinity of the solution (pH), (d) specific heavy and trace elements, (e)
soluble Fe. In general, when the leachate or leaching solutions passing
through the soil are relatively high in TOC, soluble salt, specific polluting
element, and acidity less are the chances for attenuation. Soluble Fe con-
tent is positively correlated with attenuation. The mechanism(s) for this
interrelationship is (are) not known at this time.
Specific element factors -- Prominent factors in specific element
attenuation reported in Table 4 relate to elements selected by the U.S. EPA
as As, Be, Cd, Cr, C8, Fe, Pb, Ni, Hg, Se, Zn, and V as possessing potentially
hazardous characteristics as pollutants. The elements differ greatly with
respect to migration rates through soils and geologic materials depending on
their (a) capacity to form anions or not, and (b) indiviudal chemical char-
acteristics in reacting to form soluble and insoluble compounds with their
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environmental constituents at the various pH and Eh habitats available.
Lead, for example, migrates very slowly through most soils, whereas Cd moves
comparatively rapidly.
RANKING ELEMENTS AND SOILS FOR ATTENUATION
Recognizing the pitfalls of ranking elements and soils for attenuation,
Korte et al. (1976), felt their research with 10 soils representing the 10
major orders of soil in the U.S. provided a rare opportunity to do so. The
data presented in Figures 3 and 4 display quantitatively the relative mobility
of the elements (As, Be, Cd, Cr, Cu, Ni, Pb, Hg, Se, Zn and V) and the relative
effectiveness of the soils in attenuating them. The elements naturally
separated into cations and anions as previously discussed. The soils repre-
sent all ranges of physical and chemical characteristics described earlier.
By knowning the characteristics and climatic location of these soils and com-
paring them with one's own, these figures can be useful in the selection of
the most favorable disposal sites depending on the kind(s) of metals present.
The divalent Cu and Pb may be found to be the least mobile while Hg
only weakly attenuated, Figure 3. Molokai (tropical clay), Nicholson (temper-
ate-humid, clayey loam), Mohave (arid, calcareous, clayey) soils were the
most effective in attenuating the metallic elements. Wagram (temperate-humid
sand) and Anthony (alluvium) soils were the least effective for attenuation.
The metals that form anions, Figure 4, in the leachate reorder from
Figure 3 based largely on pH and abundance of the hydrous oxides of the soils.
Thus, attenuation is more efficient for soils lower in pH and/or higher in
free oxides of iron. Free lime may or may not significantly decrease their
mobility, Fuller, et al. (1976).
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NATURAL SOIL LINERS
Among the most outstanding soil parameters that influence attenuation
of the heavy and trace elements are clay content, lime, pH, and hydrous
oxides, Table 5. With these and other known parameters certain low-cost
liners for disposal sites are suggested, Table 6. Disposal excavations,
typified by landfill sites, may be lined easily to various thicknesses of
lime, clay, and other natural soil and geological material. All sites
require modification if migration of poll-utants is to be retarded because
all in situ lanc| materials permit migration of at least some polluting con-
stituents found in waste leachates and waste solutions.
Agricultural Limestone - Limestone occurs abundantly throughout
the U.S. Moreover, the agriculture industry uses large quantities of lime
for crop nutrient control and acid abatement of soils. The agricultural
sieve sizes have proved suitable for land-sit liners, Fuller, et al. (1976).
Certain heavy metals (Pb, Cu, Al) were found to be absorbed by limestone to
a greater extent than others (Ni and Zn). Limestone may act to (a) adsorb
the metal ion directly, (b) react to form less soluble compounds as carbonate
and/or (c) raise the pH level of the leachate as it passes through the liner
barrier so precipitation may take place due to reduced solubility.
Lime-slurries containing sulfur oxides from air pollution control
may be expected to react the same way since they contain unspent limestone.
The sulfur compounds may add an additional attenuating dimension to these
slurries.
Hydrous Oxides - Although the research with hydrous oxides of Fe
shows them to be highly reactive with certain metal ions, and earlier
research indicates attenuating possibility, Korte, et al. (1975), the
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technique of managing the iron sulfate mining waste residue for liner
purposes yet needs to be worked into a practical liner program. Documented
laboratory evidence for the attenuating influence of the hydrous oxides of
Fe for certain metallic pollutants is provided also by Fuller, et al. (1976).
Organic Wastes - The abundance of nutshells (pecan, walnut, etc.)
which are highly resistant to biodegradation appear to have great capacity
to adsorb metallic ions. Lining disposal sites with ground nutshells can
reasonably be expected to initiate fixation of certain heavy metals at the
disposal sites.
Natural Soil as Sealant - The author has had considerable practical
experience in the area of completely sealing artificial lakes using natural
clayey materials taken from the lake-bed excavations. Partial and complete
sealing against leaking may be achieved depending on (a) compaction technique,
(b) clay content of soil, (c) dispersion of clay with sodium, (d) and
thickness of the liner, Fuller, et al. f(1976).
Flux - In addition to liners the density of the floor and sides of
the disposal sites can be modified to control the rate of flow (flux) of the
liquid vehicle carrying the pollutant. Thus the natural soil material can
be altered in such a way as to act as a liner by permitting the soluble
constituents more time to linger in the vicinity of the soil constituents
responsible for attenuation.
RESIDUAL MANAGEMENT: SOILS
In addition to the use of natural soil liners and soil modification
for pollution control, wise site selection and management must become an
essential part in the attempt to achieve maximum retention of potentially
hazardous pollutants. Some such residual management practices are outlined
in Table 7.
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Perhaps one of the most critical practices in site selection is to
avoid disposing of wastes in river bottoms, sand and gravel pits where there
is no hope for retention and attenuation. Most of these locations feed
directly into aquifers and underground water storage. Equally undesirable
are locations where impervious "gumbo till" or clay stratifications impede
water leakage downward. If such layers traverse the disposal site lateral
flow can take place and seepage may bring leachates and hazardous pollutants
to the surface slopes. Surface contamination associated with the usual
erosion of rainfall offers serious hazards to water pollution and food
chain entry.
RESIDUAL MANAGEMENT: LEACHATES
At least two prominent characteristics of leachates (municipal solid
waste landfill leachates, in particular) may be managed to aid in the
control of migrating metals through soils. They are (a) mixing of organic
and inorganic and inorganic source materials and/or solutions, and (b)
aeration, Table 8. Certain inorganic soluble metal compounds found in
leachates migrate more rapidly through soils when associated with organic
substances. Mercury, lead, and copper compounds are notable in this respect.
Chelation or sequestering mechanisms protecting the metals are thought to
be operative more extensively than precipitation and absorptive mechanisms.
Attenuation of some elements appear to be negatively correlated with total
organic carbon (TOC) content of leachates.
Aeration of leachate solutions (anaerobic) results in precipitation
development, Korte, et al. (1975). The precipitate is readily detected by
the dark coloration of the solution during exposure to air directly or by
aeration techniques. If landfill or excavation sites were lined at the
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bottom with plastic pipes perforated to permit pumping of air through the
leachates, retention of organic and inorganic constituents may be encouraged.
ACKNOWLEDGEMENT
Nic Korte, Elvia Niebla, Bruno Alesii, Juan Artiola-Fortuny, Joe
Skopp> and Dan O'Donnell; each have played a significant part in the progress
of this U.S. Environmental Protection Agency -- supported research program.
Tne help, so generously provided by Mike H. Roulier, U.S. EPA project
officer is gratefully appreciated.
The work upon which this publication is based was performed pursuant
to Contract No. 68-03-0208 with the U.S. Environmental Protection Agency,
Solid and Hazardous Waste Research Division, Municipal Environmental Research
Laboratory, Cincinnati, OH 45268, in cooperation with the Arizona Agricultural
Experiment Station, The University of Arizona, Tucson, AZ 85721.
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REFERENCES
1. Fuller, W.H. 1976. Migration of Selected Hazardous Metals, Asbestos
and Cyanide through Soils. Solid and Hazardous Waste Research Div. Rept.
U.S. Environmental Protection Agency, Cincinnati, Ohio, 290 pp. (in press).
2. Fuller, W.H., Colleen McCarthy, B.A. Alesii, and Elvia Niebla. Liners
for Disposal Sites to Retard Migration of Pollutants. In: Residual
Management by Land Disposal. Proceedings of the Hazardous Waste Research
Symposium, February 2-4, 1976, Tucson, Arizona. W.H. Fuller, ed. EPA-
600/9-76-015, U.S. Environmental Protection Agency, Cincinnati, Ohio,
280 pp.
3. Fuller, Wallace H. and Nic 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, 1975, New Brunswick, New Jersey. L.J. Genetelli and J. Cirello,
eds. EPA-600/9-76-004. U.S. Environmental Protection Agency, Cincinnati,
Ohio, 1976. 196 pp.
4. Hershaft, A. 1972. Solid waste treatment and technology. Environ.
Sci. and Technol. 6:412-421.
5. 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, and
Soil Pollut. 5:149-156. D. Reidel Publ. Co., Dordrecht-Holland.
6. U.S. Congress. 1972. Marine protection, research, and sanctuaries act
of 1972. Public Law 92-532, 92nd Congress H.R. 9727. Washington, OCI. 23,
1972.
7. U.S. Environmental Protection Agency. 1973. Report to Congress on
Hazardous Waste Disposal. Report 2nd Print, pp. 1-168.
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FIGURES
Figure 1. Soil: A waste treatment system.
Figure 2. Methane production from solid organic wastes.
Figure 3. Relative mobility of Cu, Pb, Be, Cd, Ni, and Hg through ten soils.
Figure 4. Relative mobility of Se, V, As, and Cr through ten soils.
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-308-
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IR R I CATION
WATER
Fig. 2. Methane production from solid organic wastes
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-310-
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-311-
-------
TABLES
Table 1. Some prominent physical soil characteristics influencing attenuation
of metals.
Table 2. Some prominent chemical soil characteristics influencing attenuation
of metals.
Table 3. Some prominent waste leachate characteristics influencing attenuation
of metals.
Table 4. Some prominent factors in specific element (metal) attenuation in
soils.
Table 5. Some soil characteristics associated with attenuation.
Table 6. Suggested low-cost soil liners for disposal excavations that aid
in attenuation.
Table 7. Residual management of soils for pollution retention.
Table 8. Residual management of leachates as an aid in attenuation.
-312-
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TABLE 1. SOME PROMINENT PHYSICAL SOIL CHARACTERISTICS
INFLUENCING ATTENUATION OF METALS
1. Texture
2. Structure
3. Stratifications
4. Flux
5. Compaction
6. Cementation - Fe, Caliche, lime, clay
7. Wetting and drying
(hydraulic conductivity)
-313-
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TABLE 2. SOME PROMINENT CHEMICAL SOIL CHARACTERISTICS
INFLUENCING ATTENUATION OF METALS
1. CLAY CONTENT
2. SURFACE AREA - REACTION SITES
3. LIME CONTENT
4. HYDROUS OXIDES - Fe, Mn, Al
5. pH-ACIDITY & ALKALINITY
6. TOTAL DISSOLVED SOLIDS - (SALTS)
-314-
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TABLE 3. SOME PROMINENT WASTE LEACHATE CHARACTERISTICS
INFLUENCING ATTENUATION OF METAL
1. TOTAL ORGANIC CARBON COMPOUNDS (TOC)
2. TOTAL SOLUBLE SALTS (Elec. Cond.)
3. ACIDITY AND ALKALINITY (pH Values)
4. SPECIFIC HAZARDOUS ELEMENT CONCENTRATIONS
(As, Be, Cd, Cn, Cu, Pb, Ni, Hg, Se, In, V)
5. TOTAL SOLUBLE IRON CONTENT
-315-
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TABLE 4. SOME PROMINENT FACTORS IN SPECIFIC ELEMENT (METAL)
ATTENUATION IN SOILS
ELEMENTS
As, Be, Cd, Cn, Cu, Pb, Ni, Hg, Se, Zn, V, Fe
1. AN IONIC REACTION
As, Cn, (Hg), Se, V
2. CATIONIC REACTIONS
Be, Cd, Cu, Pb, Ni, Zn (Fe)
3. SPECIFIC ION CHARACTERISTICS
e.g. Pb_ vs Cd_
-316-
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Major
Clay
**
Mi neral s
Clay
?5 Silt
3
>- Sand
Total Mn
Free Iron
oxides
Surface
Area
Column bulk
density
Electrical
:onductivity
of extract
Cation
exchange
capaci ty
Soil Paste
PH
Order
Series
M
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CL
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t=
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-317-
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TABLE 6. SUGGESTED LOW-COST SOIL LINERS FOR DISPOSAL EXCAVATIONS THAT
AID IN ATTENUATION
1. AGRICULTURAL LIMESTONE
2. LIME-WASTE SLURRIES
3. HYDROUS OXIDES OF Fe, Mn, and Al.
4. ORGANIC WASTES
5. SOIL MATERIALS AS SEALANTS
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TABLE 7. RESIDUAL MANAGEMENT OF SOILS FOR POLLUTION RETENTION
1. TEXTURE — Choose finer textured soils (Clays, loams).
Avoid heterogeneous mixtures
2. DEPTH -- Choose deep rather than shallow soils.
3. DRAINAGE — Choose good drainage but not aquifers
4. REACTION -- Choose the least acid soils, and
5. HYDROUS OXIDE CONTENT — Choose soils highest in Fe, Al,
and possibly Mn.
-319-
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TABLE 8. RESIDUAL MANAGEMENT OF LEACHATES FOR POLLUTION CONTROL
1. SOURCES OF LEACHATE — Avoid mixing non-compatible leachates, e.g.
Organic and Inorganic: Municipal Wastes with Industrial Wastes.
2. AERATION — Aeration precipitates organic as well as inorganic
constituents and thus retards migration.
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THE APPLICATION OF SEWAGE SLUDGES TO
E. Epstein and J. F. Parr.?/
Interest In the appliction of sewage sludge on land in the United States
as a viable means of disposal and/or utilization has increased because of
certain legislative actions and economic considerations (Colacicco et al., 1977).
Legislative actions have imposed strict limitations on sewage disposal by
incineration (Air Quality Act of 1967), by fresh water dilution (Water Pollution
Control Act Amendments of 1972), and by ocean dumping (Marine Protection, Research,
and Sanctuaries Act of 1972). Moreover, the costs for certain methods of sludge
disposal, e.g., trenching, landfill, and incineration, have increased tremen-
dously in recent years (Colacicco et_ al^., 1977). The situation is further
intensified by the dramatic increase in sludge production resulting from imple-
mentation of more advanced wastewater treatment methods. Based on current trends,
the present annual U.S. sludge production of approximately five million dry tons
is expected to exceed ten million tons by 1985.
Composition and Properties
Sludge is predominately organic matter (40 to 60 percent) and, thus can be
a valuable resource when applied to the land. Its potential use on land will be
limited by the level of contamination from toxic chemicals and pathogens.
Sludge can be applied to land as a liquid (2 to 10 percent solids), as
dewatered filter cake (18 to 25 percent solids), as a compost (40 to 70 percent
solids), or as a heat dried product (94 to 99 percent solids).
I/ Research on composting of sewage sludge reported herein was partially supported
by funds from the Maryland Environmental Service, Annapolis, Maryland, and the
United States Environmental Protection Agency, Cincinnati, Ohio.
2J Soil Scientist and Microbiologist, respectively, Biological Waste Management and
Soil Nitrogen Laboratory, Beltsville Agricultural Research Center, Agricultural
Research Service, U.S. Department of Agriculture, Beltsville, Maryland.
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Table 1 shows the composition of sludge from eight North Central States
(Sommers, 1977). The composition varies depending on the extent of treatment
and industrial contamination.
The composition of composted sewage sludge depends on the characteristics
of the sludge (raw or digested), its source (industrial or domestic), and the
composting process technology which concerns the nature and amount of bulking
material that is used (e.g., refuse or woodchips), and whether the compost is
cured, screened, and stored before use. Table 2 shows the properties of raw and
digested sludge composts. The sludges were obtained from the Washington, D.C.,
Blue Plains Wastewater Treatment Plant and composted with woodchips. These sludges
are essentially from domestic sources and, thus, relatively low in trace metals.
Potential Problems
Odors
Odors can be a major problem in land application of. sludge. Hydrogen
sulfide (I^S), ammonia (NH^), indoles, skatoles, and mercaptans produced during
sludge treatment are malodorous. Avoidance of odors during land application
requires immediate incorporation of sludge into the soil. Sites must be selected
with respect to population density, soil and drainage characteristics, and the
prevailing wind direction. Composting of sludge under proper conditions
eliminates putrefying odors so that land application of compost does not require
special precautions (Epstein and Willson, 1975).
Heavy Metals
Land application of sewage sludge can result in soil enrichment of toxic
trace elements (often referred to as heavy metals). It has been shown that
such enrichment can cause direct phytotoxic effects on plants resulting in
repressed growth and yield. Heavy metals may also accumulate in plant tissues
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which could then enter the food chain through direct ingestion by humans or
indirectly through animals (Page, 1974; Chaney and Giordano, 1977). The elements
in sludge of greatest concern are Zinc (Zn), Copper (Cu), Nickel (Ni), and Cadmium
(Cd). The first three are important because sufficiently high levels of these
elements in soil can cause direct phytotoxic effects on plants, resulting in
repressed growth and yield. The element of greatest concern to human health
where sewage sludges and sludge composts are applied to land is Cd. While Cd
is not usually phytotoxic it is readily absorbed by plants, can accumulate in
edible parts, and enter the food chain. Most human exposure to Cd comes from
food (principally grain products, vegetables, and fruits). High levels of Cd in
foods can be toxic to humans (Sandstead ej^ a^., 1974). Dietary Cd accumulates
primarily in the liver and kidney and at high concentrations can result in liver
damage and kidney failure. Environmental pollution of soils with Cd and sub-
sequent accumulation of Cd in rice resulted in the itai-itai ("ouch-ouch")
disease which occurred in the Jiatsu River basin of Japan (Yamagata and
Shigematsu, 1970). The World Health Organization has established that the
maximum permissible level of dietary Cd should not exceed 70 pg/person/day. The
United States Food and Drug Administration "Total Diet Study" (Duggan and
Corneliussen, 1972) shows that we are already approaching this level and
consequently a further increase in our dietary intake of this element would not
be acceptable.
A second source of human exposure to Cd is from smoking tobacco which usually
contains 1 to 6 ppm Cd. In this case, Cd is absorbed by the lung and can
contribute significantly to the total body burden.
The availability of heavy metals to plants, their uptake, and accumulation
depend on a number of soil, plant, and miscellaneous factors listed in Table 3.
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For example, toxic metals are more available to plants when the soil pH is
below 6.5. Thus, the practice of liming soils to a pH range of 6.0 to 6.5
is recommended to suppress the availability and toxicity of heavy metals to
plants. Soil organic matter can chelate or bind metal cations making them
less available to plants. The application of organic amendments such as
manures and composts can also lower the availability of heavy metals through
chelation and the formation of complex ions. Soil phosphorus can interact with
certain metals thereby reducing their availability to plants.
The cation exchange capacity (CEC), an expression of the soil's capacity
to retain metal cations, is important in binding heavy metals which decreases
their availability to plants. Generally, the higher the clay and organic
matter content of soils, the higher their CEC value. Heavy metals are relatively
less available to plants in high CEC soils (clays or clay loams) than in low
CEC soils (sands or sandy loams). Soil moisture, temperature, and aeration are
factors which interact to affect plant growth, uptake, and accumulation of
metals. For example, increasing the soil temperature can increase plant growth
and the availability and uptake of heavy metals as well.
Plant species, and varieties as well, vary widely in their sensitivity to
heavy metals. For example, some vegetable crops are very susceptible to injury
by heavy metals; corn, soybeans, and cereal grains only moderately susceptible,
while forage grasses are relatively tolerant. Generally, the older leaves of
most plants will contain higher amounts of heavy metals than the younger tissues.
Moreover, the grain and fruit of plants accumulate lower amounts of heavy metals
than the leafy tissues. This observation is illustrated in Table 4 which shows
the effect of sludge application rates on the Zn and Cd content of corn grain
and leaves. As the sludge rates increased, both the Zn and Cd concentrations
increased in the plant tissues. However, considerably lower amounts of these
metals were accumulated in the grain than in the leaves.
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It is noteworthy that heavy metals differ in their relative toxicities to
plants and in their reactivity in soils. For example, on an equivalent basis,
Cu is generally more phytotoxic than Zn, while Ni is considerably more phytotoxic
than either Zn or Cu. For reasons as yet unexplained, heavy metals can revert
with time to unavailable forms in soil.
USDA Guidelines to Limit Heavy Metal Loadings on Agricultural Land
In 1976 USDA recommended certain guidelines!' to limit the application of
heavy metals on agricultural land from either the landspreading of sewage sludges
or sludge composts. These guidelines are based on the best available knowledge
from scientists at a number of State Agricultural Experiment Stations as well as
USDA. Two categories of land were delineated: (1) privately owned land, and
(2) land dedicated to sludge application, e.g., publicly owned or leased land.
Table 5 shows the maximum allowable cumulative sludge metal applications
for privately owned land. It is suggested that sludges having cadmium contents
greater than 25 mg/kg (dry weight) should not be applied to privately owned
land unless their Cd/Zn is <_ 0.010. That is, the Cd content of the sludge
should not exceed 1% of the Zn content, so that Zn will accumulate to phytotoxic
levels before sufficient Cd can be absorbed by the plant to endanger the food
chain. Annual rates of sludge application should be based on the nitrogen
requirements of crops. Cadmium loadings on land should not exceed 1 kg/ha/year
for liquid sludge and not more than 2 kg/ha/year for dewatered sludge. The
soil should be limed to a pH of 6.5 when the sludge is applied and maintained
at a pH of 6.2 thereafter.
On publicly controlled land up to five times the amounts of sludge-borne
metals listed in Table 5 may be applied if the sludge is mixed into the 0 to 15 cm
3/ Copies of the draft document are available from the Office of Environmental
Quality Activities, USDA, Washington, D.C. 20250.
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of surface soil. Where deeper incorporation is practiced, proportionally higher
total metal applications may be made. These metal applications apply only to
soils that are adjusted to pH 6.5 or greater when sludge is applied.
Pathogens
Sewage sludge contains human pathogens, many of which are destroyed or
reduced in number during sewage treatment. Further reduction can be accomplished
by heat drying, composting, lime stabilization, or pasteurization. Data indicate
that disease problems related to soil application have been caused primarily by
use of raw sewage effluent, raw sludge, and night soil (Sepp, 1971; Parsons ^t
al. , 1975). Parsons et^ jil. (1975) summarized various data (Table 5) on the
survival of certain pathogens in soils and on plants. While most pathogens
survive in soil only for several days or a few weeks, the eggs of intestinal
worms such as Ascaris lumbricoides can survive for a number of years.
Soil moisture, pH, and temperature greatly influenced the survival of
pathogenic organisms. Adsorption and movement of pathogens in soil is affected
by the clay and organic matter content. Movement of bacteria through soils wa:3
generally restricted to the upper few centimeters (Romero 1970). However, Bouwer
et_ al. (1974) showed that in porous soils subjected to high flow rates of sewage
effluents, bacterial movement can occur to a depth of several meters.
Bitton (1975) cites several references regarding adsorption of viruses
on soil particles and their movement through soils. Migration of viruses
through soils was generally limited to the upper 50 cm. However, in porous media
or where fissures, fractures, or cracks in the substratum occur, movement of
viruses to groundwater is possible (Hori ^t ^al. , 1970). Epstein et^ a^. (1976),
Surge et al. (1977), and Kawata et: al. (1976) showed that sewage sludge
composting can effectively destroy coliforms, salmonella, and enteric viruses
when composting temperatures exceed 55°C for several days. Recent stuides at
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Beltsvllle, using an aerated pile method for composting raw sludge, showed that
f,, bacteriophage, a virus similar to some animal viruses but far more resistant
to destruction by heat, was completely destroyed during the first 2 weeks of the
composting period.
Miscellaneous Problems
Application of sludge to land can result in excess salts since ferric
chloride, alum, and lime are added during wastewater treatment to flocculate and
precipitate the suspended solids. There are a number of concerns associated with
the use of sludge on land; e.g., lack of public acceptance, adverse environmental
effects from odors and runoff, storage and distribution problems, and climatic
constraints. Public opposition to hauling and surface application of sewage
sludge can be a major problem. Residents along hauling routes near application
sites often object to the use of sludge on land. Improper soil or site manage-
ment can cause excessive runoff of effluent, nitrate pollution of ground or surface
waters, odors and other environmental problems. Sludge application to land may
have to be curtailed during winter months necessitating costly storage. Land
application usually requires immediate incorporation into the soil to avoid
runoff and odor problems and is, thus, dependent on weather conditions. The
costs of land spreading will also be dictated by land values near urban areas,
and the probable future limited use of the land where sludges containing high
quantities of heavy metals or persistent organic constituents are applied.
Benefits
The major benefits from use of sludge on land is from the macro- and
micronutrients it contains and from improvement of soil physical conditions.
Sewage sludge can provide nitrogen (N), phosphorus (P), Calcium (Ca), sulfur (S)
and other essential plant micronutrients. Larson (1974) estimated that sewage
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sludge produced in the United States could provide 2.5% of the nitrogen, 6% oi
the phosphorus, and 0.5% of the potassium sold as commercial fertilizers in IS'73.
Most of the nitrogen in sewage sludge is in the organic form and not readily
available for crop growth. Epstein (1976) indicated that 65 and 44 percent of
the organic N fraction in raw and anaerobically digested sludge, respectively,
was mineralized after 5 weeks of incubation in soil. Sludge application to land
often produces higher yields than comparable applications of commercial fertilizers
based on N content (Dowdy et^ al^. , 1976). This increase is most probably due to
improved soil physical properties. The addition of organic matter such as sludge,
green manure, animal manures, and composts are known to improve soil physical
properties as evidenced by increased water content, increased water retention,
enhanced aggregation, increased soil aeration, greater permeability, increased
water infiltration, and decreased surface crusting. Addition of sludge to sandy
soils will increase their ability to retain water and render them less droughty.
In clay soils the added organic matter will increase permeability to air and
water, and increase the infiltration of water into the soil profile. The
improvement of soil-water relationships in clay soil will provide more avail-
able water for plant growth. The added organic matter, particularly to clay
soils, improves tilth, reduces compaction, and increases soil aeration and
rooting depth.
Laud Application
Wastewater treatment can be primary (sedimentation), secondary (anaerobic
digestion or extended aeration), or tertiary (chemical treatment) and, accordingly,
produces primary, secondary, and chemically stabilized sludges. Untreated effluent
is not recommended for land application since it may contain human pathogens.
Treated effluents or liquid sludge (1 or 10% solids) can be applied by standard
irrigation equipment (Dowdy et_ ajL. , 1976). Two projects utilizing liquid
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effluents for both irrigation and nutrient supplementation of crops are the
EPA-Muskegon County Project in Michigan and the Chicago-Fulton County Project
in Illinois. Liquid sludge may also be injected into soil with specialized
equipment including, chisels and sweep injectors, and disc and moldboard plows.
Surface application systems consist of tank vehicles either tractor-drawn or
truck mounted which spray the liquid sludge directly on the soil or crop.
Filter cake sludge (20 to 23% solids) can be spread with a bulldozer or a
tractor-drawn manure spreader. Heat-dried sludge may be applied with a
fertilizer spreader.
Composting of Sewage Sludge
There are at least four reasons for composting organic wastes such as
sewage sludges. These include (a) abatement of odors through sludge stabili-
zation; (b) destruction of pathogens by heat generated during the composting
process; (c) production of a hygienic material that can be uniformly applied to
land; (d) and narrowing the C/N ratio of the biomass being composted.
Several years ago the Agricultural Research Service of the U.S. Department
of Agriculture at Beltsville, Maryland, developed a windrow method that has
proved to be suitable for composting digested sludge (Epstein and Willson, 1974).
This method, however, was not acceptable for composting undigested (raw) sludge
because of the greater level of malodors associated with undigested sludges.
This same research group has now developed a method for composting undigested
sludges (Epstein and Willson, 1975; Epstein e_t ja. , 1976). The method is widely
referred to as the Beltsville Aerated Pile Method, wherein undigested sludge
(22% solids) is mixed with woodchips as a bulking material, and then composted
in a stationary aerated pile for a period of 3 weeks. Other bulking materials
such as paper, leaves, or agricultural residues can be used in lieu of woodchips.
Sufficiently high temperatures are attained (above 60°C or 140°F) to effectively
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destroy pathogens. During composting the pile is blanketed with a layer of
screened cured compost for insulation and odor control. Aerobic composting
conditions are maintained by pulling air through the pile by means of a vacuum
system. The effluent air stream is conducted into a small pile of screened
compost where odorous gases are effectively absorbed.
The finished compost can be used as both a fertilizer and soil conditioner.
Large -quantities have been used as a top soil substitute by the National Capitol
Park Service and Maryland State Park Service in land reclamation and development
projects. Other uses for the compost include stripmine and gravel pit revegetation
and reclamation projects, turfgrass production, tree nurseries, and the
production of field crops. Recent research at Beltsville suggests that on a
total metal basis, heavy metals are less available to plants in composted sewage
sludges than they are in uncomposted raw and digested sludges-1'. The exact
reason for this is not known but it is the subject of continuing research.
The Beltsville Aerated Pile Method has been adopted by a number of
municipalities, including Bangor, Maine; Durham, New Hampshire; and Camden, New
Jersey; and more are likely to follow, since sludge stabilization by composting
and subsequent utilization of the compost on land is a more viable alternative
to such environmentally unacceptable disposal methods as ocean dumping, landfill,
and incineration.
Conclusions
Intensive cropping systems often accelerate the depletion of soil organic
matter thus causing the deterioration of soil physical properties which in turn
leads to increased runoff and erosion, increased nutrient losses and decreased
soil productivity. Both heavy (clays) and light (sands) soils could greatly
47 R. L. Chaney and E. Epstein, unpublished data.
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benefit from the application of sludge or sludge composts as a result of improving
their chemical and physical properties. The continuing high costs of inorganic
fertilizers has caused developing countries to consider the utilization of
urban and municipal organic wastes as fertilizers to sustain crop production.
Pathogen problems can be minimized with improved sanitary conditions, develop-
ment of appropriate process technology for composting sludge, and restriction
in the use of raw sludges on crops that are eaten raw.
Where sludges and sludge composts are applied to land, steps should be
taken to prevent the accumulation of heavy metals in food chain crops. In
cases where industries are utilizing sanitary sewers to discharge effluents
containing heavy metals, abatement and/or.pretreatment methods should be
implemented. While it is hoped that such action would be voluntary, regulatory
agencies should exercise their authority to limit the influx of heavy metals
where necessary. Heavy metals in food crops can be minimized by good soil and
crop management practices. For example, maintenance of soil pH near 6.5,
proper crop selection, and proper management of organic matter can reduce uptake
and accumulation. In addition to agronomic crops, sludge and sludge composts
can be very beneficial for use in the development of parks, reclamation and
revegetation of stripmined lands and gravel pits, and for nursery use in the
production of turfgrass, ornamentals, and trees.
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LITERATURE CITED
1. Bitton, G. 1975. Adsorption of viruses onto surfaces in soil and water.
Water Res. 9:473-484.
2. Bouwer, H., J. C. Lance, and M. S. Riggs. 1974. High-rate land treatment
II. Water quality and economic aspects of the Flushing Meadows Project. J.
Water Poll. Cont. Fed. 46:844-859.
3. Bulge, W. D., W. N. Cramer, and E. Epstein. 1977. Pathogens in sewage
sludge and sludge compost. Amer. Soc. of Agr. Eng. Trans. Paper No.
76-2560. (In press).
4. Chaney, R. L. and P. M. Giordano. 1977. Microelements as related to
plant deficiencies and toxicities. In Soils for Management and Utilization
of Organic Wastes and Wastewaters. Soil Sci. Soc. Amer., Madison, Wisconsin.
(In press).
5. Colacicco, D., E. Epstein, G. B. Willson, J. F. Parr, and L. A. Christiansen.
1977. Cost of sludge composting. Agricultural Research Service, Northeast
Regional Publication, U.S. Department of Agriculture, Beltsville, Maryland.
(In press).
6. Dowdy, R. H., R. E. Larson, and E. Epstein. 1976. Sewage sludge and
effluent utilization in Agriculture. In Land Application of Waste Materials.
p. 138-153. Soil Cons. Soc. Amer., Ankeny, Iowa.
7. Duggan, R. E. and P. E. Corneliussen. 1972. Dietary intake of pesticide
chemicals in the United States (III), June 1968 - April 1970. Pesticide
Monitoring Jour. 5:331-341.
8. Epstein, E. 1976. Impact and possibilities of reuse of sludge and
sludge compost in agriculture. In Agrochemicals in Soils. Int. Soc. of
Soil Sci. Symposium. Jerusalem, Israel. June 13-18, 1976.
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9. Epstein, E. and G. B. Wlllson. 1974. Composting sewage sludge. In
Proceedings of the National Conference on Municipal Sludge Management.
p. 123-128. Information Transfer, Inc., Rockville, Maryland.
10. Epstein, E. and G. B. Willson. 1975. Composting raw sludge, ^n
Proceedings of the National Conference on Municipal Sludge Management and
Disposal, p. 245-248. Information Transfer, Inc., Rockville, Maryland.
11. Epstein, E., G. B. Willson, W. D. Surge, D. C. Mullen, andN. K. Enkiri.
1976. A forced aeration system for composting sewage sludge. J. Water
Poll. Cont. Fed. 48:688-694.
12. Hori, D. H., N. C. Burbank, R. H. F. Young, L. S. Lau, and H. W. Klemmer.
1970. Migration of polio virus type 2 in percolating water through
selected Oahu soils. Tech. Rep. No. 36. Water Resources Research Center,
Univ. of Hawaii, Honolulu.
13. Hukuhara, T., and H. Wada. 1972. Adsorption of polyhedra of cytoplasmic
polyhedrosis virus on soil particles. J. Invert. Pathol. 20:309-316.
14. Kawata, K., W. N. Cramer, and W. D. Burge. 1976. Destruction of
pathogens in sewage solids through composting. Presented as a working
paper at the World Health Organization Seminar on Solid Waste Management.
WHO Regional Office, Manila, The Philippines.
15. Larson, W. E. 1974. Cities' wastes may be soils' treasure. Crops and
Soils. 27:9-11.
16. Page, A. L. 1974. Fate and effects of trace elements in sewage sludge
when applied to agricultural lands. A literature review. USEPA Project
No. EPA-670/2-74-005. 96 p.
-333-
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17. Parsons, D., C. Brownlee, D. Wetter, A. Maurer, E. Haughton, L. Kornder,
M. Slezak. 1975. Health aspects of sewage effluent irrigation. Pollution
Control Branch, British Columbia Water Resources Services, Victoria, B.C.
75 p.
18. Sandstead, H. H., W. H. Allaway, R. G. Burau, W. Fulkerson, H. A.
1 Laithinen, P. M. Mewberne, J. 0. Pierce, and B. G. Wixson. 1974.
Cadmium, zinc, and lead. Geochemistry and the Environment. 1:43-56.
19. Sommers, L. E. 1977. Chemical composition of sewage sludges and analysis
of their potential use as fertilizers. J. Environ. Qual. (In press).
.20. Sepp, E. 1971. The use of sewage for irrigation - A literature review.
State of California Department of Public Health, Bureau of Sanitary
Engineering, Sacramento, California.
21. Yamagata, N. and I. Shigematsu. 1970. Cadmium pollution in perspective.
Bull. Inst. Pub. Health. 19:1-27.
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Table 1. Total Elemental Composition of Sewage Sludge from several
United States Municipalities (Sommers 1977).-'
Component
Organic C.
Inorganic C.
Total N
NH+-N
NO~-N
Total P
Inorganic P
Total S
Ca
Fe
Al
Na
K
Mg
Zn
Cu
Ni
Cr
Mn
Cd
Pb
Hg
Co
Mo
Ba
As
B
Minimum
6.5
0.3
<0.1
<0.1
<0.1
<0.1
<0.1
0.6
0.10
<0.10
0.10
0.01
0.02
0.03
101
84
2
10
18
3
13
<1
1
5
21
6
4
2/
Concentration-
Maximum
%
48.0
54.3
17.6
6.7
0.5
14.3
2.4
1.5
25.0
15.3
13.5
3.1
2.6
2.0
ppm
27800
10400
3515
99000
7100
3410
19730
10600
18
39
8980
230
757
Median
30.4
1.4
3.3
1.0
<0.1
2.3
1.6
1.1
3.9
1.1
0.4
0.2
0.3
0.4
1740
850
82
890
260
16
500
5
4
30
162
10
33
I/ Data compiled from over 200 samples from 8 states.
2] Values expressed on 110°C weight basis.
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Table 2. Composition of Raw and Digested Sludges from the Washington, D. C.
Blue Plains Wastewater Treatment Plant, and their Respective
Composts Processed at the USDA Composting Facility, Beltsville, Md.
Component
PH
Water, %
Organic carbon, 5
Total N, %
NH,-N,ppm
Phosphorus, %
Potassium, %
Calcium, %
Zinc, ppm
Copper, ppm
Cadmium, ppm
Nickel, ppm
Lead, ppm
PCB^, ppm
BHC-/, ppm
DDE-, ppm
DDT , ppm
Raw
Sludge
5.7
78
'. 31
3.8
1540
1.5
0.2
1.4
980
420
10
85
425
0.24
1.22
0.01
0.06
Raw Sludge
Compost
6.8
35
23
1.6
235
1.0
0.2
1.4
770
300
8
55
290
0.17
0.10
<0.01
0.02
Digested
Sludge
6.5
76
24
2.3
1210
2.2
0.2
2.0
1760
725
19
-
575
0.24
0.13
-
Digested Sludge
Compost
6.8
35
13
0.9
190
1.1
0.1
2.0
1000
250
9
-
320
0.25
0.05
0.008
0.06
\l Polychlorinated biphenyls as Arochlor 1254.
2] The gamma isomer of benzene hexachloride is also called lindane.
^/ DDE results from the dehydrochlorination of DDT.
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Table 3. Major Factors Affecting Heavy Metal Uptake and Accumulation by Plants
Soil Factors
1. Soil pH - Toxic metals are more available to plants below pH 6.5.
2. Organic matter - Organic matter can chelate and complex heavy metals
so that they are less available to plants.
3. Soil phosphorus - Phosphorus interacts with certain metal cations
altering their availability to plants.
4. Cation Exchange Capacity (CEC) - Important in binding of metal
cations. Soils with a high CEC are safer for disposal of sludges.
5. Moisture, temperature, and aeration - These can affect plant growth
and uptake of metals.
Plant Factors
1. Plant species and varieties - Vegetable crops are more sensitive to
heavy metals than grasses.
2. Organs of the plant - Grain and fruit accumulate lower amounts of
heavy metals than leafy tissues.
3. Plant age and seasonal effects - The older leaves of plants will
contain higher amounts of metals.
Miscellaneous Factors
1. Reversion - With time, metals may revert to unavailable forms in soil.
2. Metals - Zn, Cu, Hi and other metals differ in their relative
toxicities to plants and their reactivity in soils.
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Table 4. Effect of Sludge on Zn and Cd Content of Corn
Sludge Applied
Tons/acre—
0
17.5
35
70
105
Zn
Grain
ppm
27
41
46
36
45
Leaves
ppm
35
180
224
168
143
Cd
Grain
ppm
0.04
0.11
0.21
0.17
0.20
Leaves
ppm
0.41
1.11
1.74
1.89
1.69
_!/ Application rates are on a dry weight basis.
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Table 5. Maximum Allowable Cumulative Sludge Metal Loadings for Privately
Owned Land as a Function of the Soil Cation Exchange Capacity.
Soil Cation Exchange Capacity (meq/lOOg)
Metal 0^_J 5_ 15
(Maximum metal addition, kg/ha)
Zn 250 500 1000
Cu 125 250 500
Ni 50 100 200
Cd 5 10 20
Pb 500 1000 2000
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Table 6. Survival of Certain Pathogens in Soil and on Plants (Parsons,
et al., 1975).
Organism
Media
Survival Time
Days
Coliforms
Fecal streptococci
Salmonella
Salmonella typhi
Shigella
Tubercle bacilli
Entamoeba
histolytica cysts
Enteroviruses
Ascaris ova
Soil Surface
Vegetables
Grass and Clover
Soil
Soil
Vegetables and Fruits
Grass or Clover
Soil
Vegetables and Fruits
On Grass (raw sewage)
Vegetables
In Water Containing Humus
Soil
Grass
Soil
Vegetables
Water
Soil
Vegetables
Soil
Vegetables and Fruits
38
35
6-34
26-77
15->280
3-49
12->42 (and over
winter)
1-120
180
10-49
6-8
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LONG-TERM CARE AND LIABILITY ISSUE
Related to Hazardous Waste Treatment, Storage, and Disposal Sites
by Michael Shannon*
Introduction
In the period that led up to Earth Day 1970, this country was
coming to the realization that maintaining the quality of the human
environment was the most important challenge of our age. It was
within this context that the Congress enacted the first solid waste
legislation in 1965, initiating a concerted effort to improve solid
waste management practices, and the course of extensive envrionmental
pollution across the Nation.
The Federal solid waste program was organized to carry out
provisions of the 1965 Solid Waste Disposal Act and was, at that time,
within the Department of Health, Education, and Welfare. With the
coming of Earth Day 1970 and the assembly of the main Federal environ-
mental programs into a single agency, the Office of Solid Waste became
a part of the U.S. Environmental Protection Agency. The year 1970 also
saw an amendment to the Solid Waste Disposal Act — the Resource Recovery
Act, which provided a new emphasis towards recovery of valuable materials
and energy from waste residuals. As a result of EPA's 1973 report to
Congress, Disposal of Hazardous Wastes, mandated by Section 212 of the
amended legislation, a strong thrust to bring some control to the manage-
ment of hazardous wastes throughout the United States was begun at EPA.
The new law of the land is the Resource Conservation and Recovery
Act of 1976 which was signed by President Ford on October 21 and desig-
nated as Public Law 94-580. The new law phases out open dumping of
solid wastes, upgrades land disposal, provides Federal financial and
technical assistance to State and area-wide programs which are environ-
mentally sound and makes optimal use of opportunities for resource
recovery. Limited Federal support for resource recovery demonstrations
would be provided through the mechanism of loan guarantees. Expanded
Federal technical assistance and information efforts would be authorized
to assist States, local governments and industry in every aspect of
solid waste management. Those who treat, transport, store, or dispose
of hazardous wastes will need to obtain permits for their activities.
This paper will focus on several non-technical aspects of the hazardous
waste management regulations.
*Mr. Shannon is a program manager with the Implementation Branch,
Hazardous Waste Management Division, Office of Solid Waste, U.S.
Environmental Protection Agency.
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The problems of perpetual or long-term care and liability
of hazardous waste management facilities are of vital concern to
the public. Facilities as used here include hazardous waste
treatment, storage, and disposal operations/sites. In fact, the
recently passed 1976 Resource Conservation and Recovery Act contains
elements which are adddressed to these issues. Specifically, Subtitle
C - Hazardous Waste Management, Section 3004.6 "Standards Applicable
to Owners and Operators of Hazardous Waste Treatment, Storage, and
Disposal facilities" states that the standards shall include "such
additional qualifications as to ownership, continuity of operation,
and financial responsibility as may be necessary or desirable." In
order to protect the public and the environment from harm, this Act
recognizes that certain measures are necessary to ensure financial
responsibility and long-term care of hazardous waste management
facilities.
These requirements are included because from a regulatory
standpoint, technical standards and record-keeping and reporting
requirements must be re-enforced by incentives for good management
and complete protection. The requirements give the public the
knowledge that persons in the business of hazardous waste manage-
ment are responsible and can be held accountable for their
actions. In addition, financial responsibility and continuity
of operations requirements give the owners or hazardous waste
management facilities a degree of protection against the financial
aspects of pollution incidents and lawsuits. The mere fact that
there is a law increases the visibility and responsibility of
persons in the industry and simultaneously gives the public a
vehicle for comparison and to bring suit.
There are two related approaches that have to be considered
in implementing long-term care and liability provisions. The
first approach relates to continuity of operation and ownership
requirements or to the transfer of site operations from one operator
to the next, as well as the final closing and subsequent monitoring,
surveillance, and maintenance of the hazardous waste facility. This
paper will address the problem of assuring adequate funds for site
closure and long-term care at any point in the life of the site.
Once such provisions have been established, the financial responsi-
bilities can be transferred with a change in site operators.
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THE DILEMMA OF LIABILITY
AND
PERPETUAL CARE ISSUES
Prepared by
Michael Shannon
Hazardous Waste Management Division
Office of Solid Waste Management Programs
U.S. Environmental Protection Agency
for presentation to the
Fifth National Congress
of the
National Solid Waste Management Association
Dallas, Texas
December 9, 1976
-------
THE DILEMMA OF LIABILITY
AND
PERPETUAL CARE ISSUES
by Michael Shannon*
Introduction
In the period that led up to Earth Day 1970, this country was
caning to the realization that maintaining the quality of the human
environment was the most important challenge of our age. It was
within this context that the Congress enacted the first solid waste
legislation in 1965, initiating a concerted effort to improve solid
waste management practices, and the course of extensive environmental
pollution across the Nation.
The Federal solid waste program was organized to carry out
provisions of the 1965 Solid Waste Disposal Act and was, at that time,
within the Department of Health, Education, and Welfare. With the coming
of Earth Day 1970 and the assembly of the main Federal environmental
programs into a single agency, the Office of Solid Waste Management
Programs became a part of the U.S. Environmental Protection Agency.
The year 1970 also saw an amendment to the Solid Waste Disposal Act —
the Resource Recovery Act, which provided a new emphasis towards
recovery of valuable materials and energy from waste residuals. As
a result of EPA's 1973 report to Congress, Disposal of Hazardous
Wastes, mandated by Section 212 of the amended legislation, a strong
thrust to bring some contol to the management of hazardous wastes
throughout the United States was begun at EPA.
*Mr. Shannon is a Program Manager with the Implementation
Branch, Hazardous Waste Mangement Division, Office of Solid
Waste Management Programs, U.S. Environmental Protection Agency-
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-------
The problems of perpetual or long-term care and liability
of hazardous waste management facilities are realistic and
are of concern to the public. Facilities as used here include
hazardous waste treatment, storage, and disposal operations/
sites. In fact, the recently passed hazardous waste management
legislation contains elements which are addressed to these
issues. Specifically, the language of the 1976 Resource
Conservation and Recovery Act under Subtitle C - Hazardous
Waste Management, Section 3004.6 "Standards Applicable to
Owners and Operators of Hazardous Waste Treatment, Storage,
and Disposal Facilities" states that the standards shall include
"such additional qualifications as to ownership, continuity of
operation, and financial responsibility as may be necessary or
desirable." In order to protect the public and the environment
from harm, this Act recognizes that certain measures are necessary
to ensure financial responsibility and long-term care of hazardous
waste management facilities.
These requirements are included because from a regulatory
standpoint, technical standards and record-keeping and reporting
requirements must be re-enforced by incentives for good management
and adequate protection. The requirements give the public the
knowledge that persons in the business of hazardous waste
management are responsible and can be held accountable for their
actions. In addition, 'financial responsibility and continuity
of operations requirements give the owners of hazardous waste
management facilities a degree of protection against the financial
aspects of pollution incidents and lawsuits. The mere fact that
there is a law increases the visibility and responsibility of
persons in the industry and simultaneously gives the public a
vehicle for comparison and to bring suit.
There are two related approaches that have to be considered
in implementing long-term care and liability provisions. The
first approach relates to continuity of operation and ownership
requirements or to the transfer of site operations from one
operator to the next, as well as the final closing and subsequent
monitoring, surveillance," and maintenance of the hazardous waste
facility. This paper will address the problem of assuring adequate
funds for site closure and long-term care at any point in the life
of the site. Once such provisions have been established, the
financial responsibilities can be transferred with a change in
site operators.
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The second approach encompasses the financial responsibility
of operators of hazardous waste managment facilities. Here the
concern is more with the assessment of liablity for damage
occurrences related to hazardous waste. The reauirement of
liability insurance is discussed as the means for insuring financial
responsibility.
Long-term Care
Previous experience with the long-term care of hazardous
waste managment facilities is limited. One method of ensuring
long-term site care is to require deposit of a cash bond or
maintenance of a surety bond by the hazardous waste management
facility operator. The bond must be of sufficient size to assure
proper site closing and site monitoring, surveillance, and main-
tenance for a specified number of years. The appropriate bonding
level should consider site characteristics (size, geology, hydrology,
etc.), the particular hazardous waste destined for storage, disposal,
the degree of waste treatment prior to disposal, and the likelihood
of off-site damages (i.e., proximity to population centers, etc.)
should be considered as well, although it has not previously been
a factor, when choosing an appropriate bonding level. A surety
bond would probably be less burdensome to the site operator than
a cash bond of an equivalent amount. The premium paid for a surety
bond presumably being less than the cost of a loan needed for
deposit of a cash bond.
In the case of a cash bond, adequate provision for perpetual
site care is assured if the annual real rate of return (i.e., the
return on the principal over and above the rate of inflation) offsets
the cost of site upkeep. A portion of the bond could be used to
correct major site deficiencies or to offset damages caused by
leachate run-off or migration. Sufficient funds would have to
remain in escrow to provide for annual site upkeep subsequent to
such expenditures. If a change in facility operators occurs (in
advance of site closure), then the former site operator should be
allowed to withdraw the bond's principal and the new operator
required to deposit an equivalent amount.
An alternative to the required bond deposit is assessment
of a perpetual care fee on each user of the waste facility.
The user surcharge would be fixed on a volumetric basis. In
general, facility site operators have not varied this fee with
the type of incoming waste. The aggregate fees are deposited
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in an account, and when a level sufficient to maintain long-term
care of the site has been reached (including accrued interest),
the fee may be discontinued. (Of course, the fee may be calculated
such that the desired fund level will not be reached until the
site is full.) The major drawback to this method of financing
long-term- site care is that the operator can cease facility
operations without having accumulated a fund large enough to
assure adequate facility closure and perpetual care.
Either a cash or surety bond can be combined with a perpetual
care fee to provide for perpetual site care. A cash bond deposited
with a State could be withdrawn when an equivalent amount accumulated
through aggregate perpetual care fees has been deposited by the
site operator. Alternatively, a surety bond, equal to the difference
between the apparent required sinking fund and the expected size
of the sinking funds for that year (i.e., cumulative perpetual
care fees plus accrued interest), could be required of the site
operator. The apparent required sinking fund would be a site
specific reserve sufficient to provide for routine maintenance,
surveillance, and monitoring costs, as well as contingency funds
in the event of major facility repair. In essence, this method of
assuring long-term care would require the site operator to purchase
declining term insurance to protect a State against early close-out
of site operations.
A combined surety bond/perpetual care fee was suggested as
an adequate means of financial security for one of serveral low-level
radioactive waste sites in the United States. The apparent required
sinking fund was to be calculated on an annual basis, i.e., varying
with the amount of waste deposited at the disposal site. An
appropriate size for the contingency fund was calculated on the basis
of the "expected value" of major site repair costs (i.e., the sum of
projected repair costs multiplied by their respective probabilities
of occurrence). Alternatively, a contingency reserve sufficient to
cover the estimated cost of major site repair, given the need for
such action, could be required as part of the apparent required
sinking fund.
Rather than accumulate a perpetual care fund for each
hazardous waste management facility, a mutual trust fund is
another option that could be developed for all sites within
a given jurisdiction (e.g., within a State). This proposal
could be funded by any of the foregoing mechanisms. The trust
fund would provide a larger reserve to cover unexpected site
repairs or damage claims. Also, due to the pooling of the risk
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of major site repair, the contingency reserve required of each
site operator would be less than that needed if a separate
sinking fund was maintained for each site. Private operators
might not be as careful in site construction and maintenance
if they are not directly liable for these costs, however, the
enforcement aqency would have to provide the incentive for
continued site care.
Another option for long-term site care is a convenant which
is placed on the land to prohibit the transfer of site maintenance
responsibility with the deed unless the new owner accepted the
responsibility and was capable of guaranteeing continued site
maintenance. The question then arises of what constitues capability
to guarantee site maintenance. The owner would probably have to
offer some sort of financial security in order to guarantee site
maintenance. A long-term care fund, similar to the alternatives
just mentioned, might well have to be established. Thus, this
method of ensuring long-term care is not really a discrete proposal,
but rather a different context for posing the problem of adequate
financial security for long-term care.
Liability
Some States which have hazardous waste management legislation
require that disposal sites be deeded to the State and that
performance bonds be posted to obtain a license to operate
(e.g., Oregon, Washington). These requirements should improve
long-term care of disposal sites and reduce the liability problem
for the private sector. Previous owners, however, could still be
held liable for damages which arose from their actions. Oregon, or
any State, if acting as a proprietor could be open to suit or there
may be State statutes permitting tort claims against the State.
Just a's there are questions about private and public sector
roles in long-term care and liablity, there are questions regarding
liability for consequences concerning incidents entirely involving
the private sector that occur after a change in ownership of the waste
or that occur as a result of operations by a previous owner
of the facility. The confusion over responsibility partly
stems from the fact that the liability laws and the judicial
processes vary from State to State and from municipality to
municipality. As a consequence, it is possible to hear opinions
that liability for damages from a hazardous waste can be entirely
transferred from a generator to a disposer of the waste or that
most States adhere to the rule that the generator always bears
at least some of the liability.
-348-
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In an effort to better understand some of the information
regarding long-tern liability, this part of the paper will focus
on first, a discussion of the assessment of liability for
occurrences related to hazardous wastes. Next there will be
a discussion of nuclear liability insurance followed by the
hazardous waste service industry experience with liability
insurance. The final part is a discussion of the implementation
of the insurance technique as a tool for insuring financial
responsibility and long-term care of hazardous waste management
facilities.
There are two areas of law that apply to hazardous waste
in connection with damages - tort liability and criminal lav;.
Tort liability is resolved in a civil action brought by a private
plaintiff representing his own interest. In criminal action,
a public official will bring suit on behalf of broad social
interests. The "Rivers and Harbors Act of 1899" has sometimes
been used by Federal officials as the legal basis in a criminal
liability case against polluters. Hazardous waste management
is covered by specific statute in only a few States and covered
by the 1976 Resource Conservation and Recovery Act.
Since civil actions are the most common to hazardous waste
damage cases, the four theories of tort liability including
negligence, strict liability, nuisance, and trespass will be
discussed. Although the distinctions between the four theories
are sometimes not clear at the applied level the following
discussion summarizes their main features.
Negligence bases liability on the failure to use the proper
degree of care in conducting an activity. It usually involves
an operational defect or omission of a reasonable precautionary
measure. The concept of reasonableness is based to some extent
on generally employed standard practices but varies with the facts
of the particular situation.
At the other end of the spectrum, the theory of strict
liability imposes liability without regard to the degree of
care or precautions taken to prevent damage. Losses are auto-
matically shifted to the party who initiated the damage-causing
activity. The application of this theory is generally applied
to those activities that pose a considerable threat to others
even when conducted with every possible precaution.
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The concept of nuisance falls between the theories of
negligence and strict liability with regard to the requirements
for liability. Applications generally involve unreasonable
interferences with the use and enjoyment of land resulting from
the actions of other parties. Emphasis is on the invasion of
the injured party's rights rather than on the reasonableness of
the initiator's conduct with the courts using discretion on
balancing the interests involved. Although negligence is not
always a requirement for proof of nuisance, proof of negligence
is often accepted in support of an allegation that a nuisance
exists. Nuisance can look very much like the strict liability
concept when liability is based on the results of an activity
without regard to the care or precautions employed.
Trespass usually involves an unauthorized entry onto the
land of another or an invasion of property rights. The entry
or invasion need not be by a person, but may be accomplished by
something within the control of that person, which brings escaping
hazardous wastes within the scope of trespass.
The success of a plaintiff's legal action depends on his
successful presentation of proof of damages. The elements of
proof required vary among the liability theories but in general
include: 1) necessity of showing injury; 2} establishment of
causation; 3) establishment of fault. These three elements of
proof deserve more detailed explication. The injury can take
various forms: 1) actual physical injury to person or property,
which is the most significant form; 2) infringement of legally
protected rights; 3) anticipated injury. The view that infringe-
ment of a legal right constitutes injury in itself usually arises
in a trespass case which primarily involves unauthorized entry
onto the land of another. Here suit is brought not for an actual
injury, but rather for vindication of a right. Anticipated injury
by trespass or nuisance involves suits brought in prohibitory
injunctions. Injunctions traditionally are granted to a complaining
party only if it can prove the likelihood of direct injury to his
rights.
Physical injury from the polluting effect of hazardous
wastes can take a variety of forms including loss of or damage
to human life, livestock, crops, water supplies, aquatic life, etc.
In cases where compensatory damages are sought through litigation,
the plaintiff normally must quantify his injury in monetary terms
which may be possible in some situations, but not very feasible
in others. Traditionally if an injury cannot be measured, it
-350-
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goes uncompensated. If the plaintiff is unable to prove damages,
he still may be awarded an injunction especially if something
unique is injured or there is a denunciation in property value.
The judge or jury may adjust damages to reflect their interpretation
of an injury.
The plaintiff must also prove the source of the injury.
In some cases involving a hazardous waste incident, the cause
and effect relationship will be obvious. In a groundwater
pollution incident, as the distance between a disposal facility
and the injury increases and as the spread of leachate is affected
by natural processes, the positive identification of a source
becomes more difficult. Incomplete knowledge about the movement
of a groundwater pollutant generally makes a causal relationship
difficult to prove especially if the alleged incident occurred
over a long period of time. However, a good case might be possible
if direct evidence in a case of injury from groundwater pollution
can be obtained. For example, if a dye or other tracer is deposited
at the site of the pollution incident and it then appears at the
place of injury. The courts in some cases may accept indirect
proof based on circumstantial evidence. It is difficult to generalize
with regard to the evidence necessary for proof, but there are
several key factors. Included are the proximity of the incident
to the injury site, the time relationship between the incident
and occurrence of injury, the existence of a physical connection
and the elimination of other possible sources for the injury.
In addition to proof of injury and of a causal relationship,
the plaintiff in some cases may also have to prove that the
injury resulted from improper conduct on the part of the defendant
through fault or culpability. Negligence is of primary interest
here since the underlying basis of this theory is the failure to
conform to a certain standard of conduct which is based on the
conduct of the hypothetical "reasonable man". Compliance with
industry-used practices is not necessarily a successful defense
against negligence actions. Proof of. negligence by a defendant
poses a formidable obstacle where the activities in question
occurred on the defendant's property and involved operations
exclusively within the defendant's knowledge. Some courts have
accepted general proof of negligence in place of proof of specific
details. On the other hand, allegations of negligence have been
turned down in courts because of an absence of a reasonable
basis for the anticipation of harm in connection with conducting
lawful activities.
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Other cases decided under the strict liability theory have
imposed liability for injury from escaping pollutants without
regard to fault. Liability here is viewed as an integral part
of conducting hazardous activities, and this approach stresses
accountability through compensation for injuries. The strict
liability theory only requires the plaintiff to show injury and
a causal relationship with the defendant's operations. The
strict liability concept in various forms has been accepted
in 30 States with the number grov/ing at a rate of about one per
year. Guidelines for defining hazardous activities include six
factors: 1) degree of risk to the person or property of others;
2) seriousness of potential harm; 3) risk elimination by exercise
of reasonable care; 4) common usage of activity; 5) appropriateness
of activity relative to place where carried on; 6) value of the
activity to the community. These guidelines were applied to a
Maryland case where an owner of a large gasoline tank in close
proximity to a water well was held liable when gas leakage
contaminated the well.
Environmental law and case law is very meager on the subject
of responsibility of a polluter or a waste generator and someone
acting on his behalf to manage or control the pollution. In
addition to assigning direct liability to the person causing
the damage, there is a secondary type of liability for aiding
or instigating an environmental occurrence. In this unsettled
area of law, it is generally necessary to rely on the established
law of liability of contractors. This is of great importance
in hazardous waste management because of the importance of off-site
treatment and disposal of hazardous wastes.
A typical definition of a hazardous waste management firm
acting as an independent contractor is one who exercises an
independent employment and contracts to do specified work according
to his own methods, without being subject to the supervision and
control of his employer (waste generator) except for the results
desired. This definition is important when establishing whether
or not a relationship between hazardous waste generator and a
management firm is that of an independent contractor or employer -
employee. The kind of relationship will answer in many cases the
question of the liability of the employer for personal injury or
property damage to others from wrongful acts of the contractor
or his employees. The general rule in the United States is that
the employer is not liable for the wrongful acts of one who is
found to be an independent contractor. There is no absolute test
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for determining whether a person is an independent contractor or
an employee; each situation must be determined on its own facts.
The degree of control exercised by the employers is a cannon
factor, however.
An exception to the non-liability of an employer occurs
when he (or his agent) negligently hires an incompetent contractor
who the employer knew or should have known, had he used due care,
was not qualified to perform the work. Another exception occurs
when an employer is aware of a violation of a law by his independent
contractor and does not protest or attempt to rectify the violation.
In this situation the employer cannot escape liability.
A valuable source of information for its relevance to the
implementation of liability and insurance requirements is a report
entitled Nuclear Insurance - An Estimate of the Cost of the Nuclear
Hazard. It is valuable because of its description of the insurance
mechanism used for covering liability due to nuclear hazard. The
Price-Anderson Indemnity Act of 1957 (an amendment to the Atomic
Energy Act of 1S54) initiated and fostered the nuclear insurance
and indemnification program in the United States. The Act was
extended in 1976 to an effective date of 1985.
The main features of the Act regarding insurance requirements
are: 1) the Nuclear Regulatory Commission (NEC, formerly AEC)
requires financial protection for licensees; 2) the amount of
financial protection must be the amount of liability insurance
available from private sources; 3) the Federal Government provides
an indemnity above the financial protection required of the
licensee (the maximum indemnity for each nuclear incident for all
persons indemnified is $560 million); 4) the NRC is authorized
to collect a fee from all persons with whom an indemnification
agreement is executed (the fee is based on generating capacity);
5) the NKC has the responsibility for implementing and administering
the Price-Anderson Act.
The scope of coverage of government indemnification includes
practically all nuclear incidents involving transportation, storage,
or reactor operation whether nuclear fuel or nuclear waste. Coverage
extends to any person legally liable for an incident. The maximum
indemnification of $560 million was legislatively set in the 1957
Act as a realistic and affordable ceiling after testimony from
nuclear experts, insurance underwriters, and others was evaluted.
The fee charged for coverage, however, is not specified on the
basis of risk estimation.
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The "nuclear energy hazard" being insured is defined as "the
radioactive, toxic, explosive, or other hazardous properties
of nuclear materials, when such materials are at the designated
facility or are being transported to or from the facility."
Unlike traditional liability, bodily injury and property damage
liability are combined for nuclear hazard. Also, the policies
are continuous rather than for a specified period of years.
The nuclear liability insurance offered by two worldwide
liability polls is currently $125 million for each nuclear site
insured. The nuclear liability insurance premiums were established
for the two pools by rating and underwriting bureaus. Since
there originally was not actuarial experience, the premium rate
formula was based on judgment. The underwriters established
a base rate for the first $1 million of insurance with the percent
of the base rate per $1 million of insurance declining for additional
increments. The factors considered in establishing a base rate
are: 1) reactor type; 2) intended use (power, test, research);
3) designed power load; 4) location in relation to population
and property exposure; 5) degree of containment. The premium cost
for a nuclear power plant in 1971, which had the insurance limit
per location of $82 million, ranged from $170,000 to $325,000.
A unique feature of the nuclear insurance policy is a
credit rating plan which exists because of the judgmental
factors used in setting premiums. A part of the premiums (67% to
75%) goes into a reserve fund for possible refund. The credit
is determined on the basis of loss experience over the preceding
10 year period.
Fran the viewpoint of the consumer who ultimately must bear
the cost .of the insurance, the added electricity cost due to
nuclear insurance is 0.5% of their electric bill.
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The determination of a fair rate of liability insurance
is a significant problem to the insurer (and to the insured)
when a decision is made to extend coverage to a new area such as
hazardous waste management. A basic function of an insurance
company is to respond to new needs in spreading risk for a business
firm which is in a new and risky business and is concerned with
unknown costs of insurance. In evaluating a hazardous waste
management facility risk situation, an insurance company is
concerned with three elements: frequency, severity, predictability.
To an insurance company, most risk situations are completely
insurable from the private sector (exclusions would be nuclear
occurrences and climatic castastrophe) especially if the occurrences
are predictable. The high severity of an occurrence is not a
critical insurance problem as long as the frequency is low. The
high frequency, high severity risk occurrence is a troublesome
insurance problem. Risk assignment or actuarial experience
concerning the interrelated elements of a hazardous waste framework
are generally lacking regarding occurrences because of the infancy
of hazardous waste management.
Two specific problem areas appear of concern to insurance
companies regarding risk coverage. The first problem, which may
be peculiar to hazardous waste, is the delayed effect of some
incidents. This actually adds a fourth element to a hazardous waste
risk situation. Not only is there limited knowledge about the
frequency, severity and predictability of a hazardous waste
occurrence but experience on the suddenness of an occurrence
versus delayed effects is almost nonexistent. Ordinary liability
policies will cover accidental and sudden risk situations but
to cover the long-term consequences of hazardous waste incidents,
special policies may be required.
Communications with the insurance company which until several
years ago offered fleet and landfill coverage to National Solid
Waste Management Association (NSVJMA) members, indicated that the
company's underwriters were greatly concerned about the potential
for a major groundwater or surface water pollution case. Most
of the firms covered by the group insurance policy were strictly
solid waste landfill firms. Although the liability coverage
was dropped for NSWMA members because of a poor experience
(loss) on the fleet operations, an underlying factor was that the
insurance company was aware of and somewhat apprehensive about the
delayed aspect of a groundwater or surface water pollution occurrence.
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Another significant problem area is the social aspect of an
insurance company providing liability insurance to protect the
activity responsible for an environmental damage occurrence.
According to a spokesman for the insurance industry, public interest
groups and their "hang the polluter" attitude have generated
opposition against relieving a polluter (private company) from a
burden associated with an occurrence. This attitude has impeded
the field of pollution liability insurance and made it difficult
for insurance companies to enter new fields, e.g., hazardous
waste facility liability. Pressure from environmentalists has
made it very difficult for oil tanker companies to obtain oil
spill insurance. Some companies, as a result, have been forced
to obtain liability insurance coverage from European companies.
There are two kinds of liability insurance. One is the
insured peril coverage for direct loss or damage to person(s)
or property such as from a fire or explosion. The peril inclusion
in a liability policy includes things not unique to hazardous
wastes and should not present any problem for hazardus waste service
firms. The other area of liability insurance is civil action
protection against a loss causing event sustained by a plaintiff -
commonly called "an occurrence" by an insurance company. As far
as the concept of liability is concerned regarding insurance,
the insurance company is not concerned about whether or not the
occurrence is due to trespass, negligence, nuisance, or strict
liability.
A progressive hazardous waste service firm obtains liability
insurance from a competitive desire to offer the best and most
secure service. Ideally, a hazardous waste generator would select
a service firm who is technically qualified. If interested in
doing business, the service firm in turn would analyze the waste
stream to determine if it is capable of treating, storing or
disposing of the waste. Any subsequent agreement to do business
usually means the signing of a contract. Upon pick-up and
receipt of the waste under a contract, the title changes hands
and the service firm assumes liability for the hazardous waste.
Generators normally would insist on this provision in their
contracts. Actually a service firm, according to contract, would
intend to assume liability for problems that are his "sole"
responsibility. What this actually means in terms of a lawsuit
and shared responsibility has yet to be tested in the courts.
Punitive damages are excluded from coverage by the insurance
company and must be borne by the activity.
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Information is particularly limited regarding the scope
of insurance coverage. It appears that most insurance coverage
by either the generator or the service fir?-, is the insured peril
coverage and not coverage for a civil action to protect against
lavjsuits based on serious hazardous waste occurrence. The average
liability.coverage under the NSWKA group policy was $100,000 per
occurrence for bodily and personal injury and $300,000 per occurrence
for property damage. The insurer would offer whatever a company
wanted to buy with some policies having coverage as high as
$5,000,000/510,000,000. One hazardous waste service firm (not
under the NSWMA policy) has coverage of $500,000 bodily, $500,000
personal and $3,000,000 for property for each occurrence. The
firm's annual insurance cost is estimated at about $10,000 or
less than a penny per gallon. However, this policy is for insured
peril coverage and does not address the accidental and long-term
occurrences. Other than nuclear insurance, the closest experience
to hazardous waste is for damage from water and air pollution
whereby it costs $50,000 per year for $1,000,000 of liability
insurance to cover exclusions from a general liability policy.
When areas of new coverage are offered, insurance underwriters
rely heavily on positive technical aspects of an operation such
as chemical processing or detoxification which reduces the
potential hazard. They also require compliance with applicable
standards. Because of a lack of actuarial experience, rates
are set artificially high with the service firm reliant upon
insurance company competition and credit rebates to reduce the
cost of insurance. A high risk situation may require an insurance
corr.pany to reinsure the activity with a specialty insurance
company. This allows the insurance company to share or to spread
its risk and gain added experience and a second judgment. Most
importantly it means insurance coverage is provided.
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S ummary/Conclusions
Long-term care and financial responsibility regarding
hazardous waste facilities under the new Act appropriately call
for regulation at the State level of government. States are
able to implement regulations for facilities located in the same
geographic area and account for problems unique to an area.
They will be able to incorporate local peculiarities into the
long-term care and insurance standards. Federal standards,
i.e., minimum acceptable provisions for long-term care or Federal
approval of each State's regulations, would be necessary in order
to avoid discrepancies between States.
Although standards are not required until 18 months
after Bill enactment, a combined surety bond/perpetual care fee
appears to be an equitable and effective method of ensuring
long-term site care. A mutual trust fund, pooling the risk of
environmental damage and major site repair, could encourage
investment in the hazardous waste management industry. A trust
fund, however, could not be established unless there was strict
enforcement of hazardous waste management regulations. Formulation
of specific long-term facility care regulations would be a State
responsibility. "Acceptable" regulations will have to be generally
defined by EPA.
A discussion of liability indicates three things. Firstly,
problems such as quantifying damages and proving causation related
to hazardous waste incidents will always exist. Secondly,
although environmental law, including hazardous waste law, is
incomplete end often contradictory, it is likely that as it
evolves the use of the strict liability theory will increase.
Thirdly, these things will in turn increase the necessity for
hazardous waste generators to hire competent hazardous waste
management firms. Despite these desirable changes in hazardous
waste management and law, incidents will occur for which generators
and service firms will need some form of financial protection.
Insurance is one such form of protection.
Recommendations for liability insurance are somewhat more
difficult to make. Less is known about insurance as it relates
to hazardous occurrences. What can be said is that the financial
responsibility requirement requires that an operator have insurance
against a hazardous waste pollution incident versus the standard
liability protection. Many questions, however, need answers
before standards can be set for financial responsibility. Should
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the amount of financial protection required for an incident be
set at the amount of liability insurance available from private
sources? Can it be assumed that the private insurance industry
would be able to provide "adequate" liability coverage and that
government indemnification will not be required? Is it reasonable
to require a hazardous waste management firm to obtain coverage
over all aspects of operating a hazardous waste facility including
transportation accidents, contamination incidents and other
risk activities associated with long-term consequences even after
closure of a facility and/or a change in ownership? To an insurer,
one thing is clear, the operator of a facility, as a condition
for obtaining insurance, would be required to meet all standards
associated with the operation of a hazardous waste management
facility as a condition for obtaining insurance.
Hazardous waste disposal sites, for example, will ultimately
reach full capacity and must be closed; but the potential for
occurrences still remains. Regardless of the kind of firm
originally owning such a facility or the current ownership whether
public or private, liability for damages is an important fact
or burden that someone may have to bear. Certainly the possibility
exists that the owner and operator of a closed hazardous waste
facility still under his ownership could be held liable for long-
term damages. The problem is complex when ownership has changed.
In order to provide protection in the event of future occurrences
after closure, the liability insurance requirement must include
coverage for long-term damage regardless of whether ownership
is retained or not.
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LONG-TCRM SITE KAINTtC/.dCE PROBLEMS
AND THE POTENTIAL FOK LIABILITY
By
John
-------
The purpose of this paper is to review the technical aspec f
sanl.tary landfill post-operation problems, their causes, and t\- r
solution.
First, the problems. The principal so-called post-construction
liability and "perpetual care" problems Include the impact of gas or
leachate on the environment, settlement performance of landfill, erosion
of landfill cover soil, various aesthetic issues, and the impact of the
landfill on property values.
GAS
Landfills produce gas, varying only in total quantity and the time
frame In which It is produced. Carbon dioxide, one of the principal
gases of decomposition of refuse, has liability association, principally
related to its solubility in water, creating a weak acid, corrosive
environment, and increasing water hardness. Relatively little concern
Is directed to preventive, or remedial, action insofar as carbon dioxide
Is concerned, and as such it will not be addressed further in this
paper.
Methane, the other principal gas from refuse decomposition, is
highly combustible in certain concentrations in air, a characteristic
that gives methane a dual personality. On the positive side, methane
can be a definite asset, representing, in certain cases, an economically
recoverable energy resource. On the negative side are hazards and
liabilities associated with uncontrolled release of the gas from the
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fill confines, with an accompanying possibility of fire, or when accum-
ulated in confined areas, explosion.
The production of methane gas as a function of time Is of interest
for at least two reasons: (1) to evaluate the expected "active gas life"
of a landfill, and (2) to consider the feasibility of recovery of methane
for energy. Consider that methane gas is generated only from the organic
matter which may be characterized as in Table 1.
TABLE 1
METHANE GENERATION FROM ORGANIC MATTER
n, =„!,- M,.-* .- Active Life Composition
Organic Hatter Half Life 30% of Life (*)
(years) (years)
Readily Biodegradable 0.5 - 1.5 i - 3 9
Food Wastes
Moderately Biodegradable 5-25 15-80 91
Paper Products
Garden Waste
Textlle Products
Wood
Non-biodegradable 50-00 — o
Rubber
Plastic
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It should be noted that more than 90 percent of methane gas produced
Is generated from the moderately biodegradable fraction of which paper
products predominate. To merely close a site does not stop gas production
which may continue for 20 to 100 years.
The potential for gas hazard is probably present to varying degrees
at the majority of landfills. The liability aspects of landfill-
produced methane are generally recognized throughout the industry.
Concern for methane sterns from its combustibility when present in concen-
trations between 5 and 15 percent by volume in air. While fire alone is
concern enough, combustion initiated within a confined space can result
In an explosion. If migrating methane accumulates in a poorly-
ventilated area (i.e., building subfloor, basement, closet, utility
vault, storm drain) and achieves combustible concentrations, d hazard to
public safety and/or property exists. Since methane is usually present
!n concentrations above the combustion range within landfills, it always
must pass through the combustion range as it is diluted with air.
Fortunately, under the majority of circumstances, a combustion energizer
such as an open flame is not present during passage through the critical
range and combustion does not occur. The numerous instances on record
of fires and explosions resulting from landfill-originating methane,
however, serve to warn that all too often gas migration proves hazardous.
The movement of gas to the limits of a refuse fill and into the
surrounding soils occurs by two basic processes: convection, or movement
In response to pressure-temperature gradients; and diffusion, or movement
from areas of high gas concentration to regions of lower concentration.
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Gas flow Is greater through materials with large pore spaces and high
permeability (i.e., sands, gravels) and lower In materials of lower
permeability (i.e., clays). Gas migration from landfills Is therefore
dependent In part on the geological environment of the site. In general,
a landfill constructed in a sand-gravel environment experiences greater
vertical and lateral movement of gases than one in a clay environment.
Being lighter than air, methane tends to rise and will exit prefer-
entially through the landfill cover if it is of sufficient permeability.
A cover of clay with small diameter pores tends to retain moisture in
Its pores and is thus relatively impermeable, and tends to restrict gas
loss. Any type of soil may be made less permeable by saturation with
rain or irrigation water, or by paving or frost. In such instances gas
flow through the cover will be impeded, and lateral migration will be
encouraged. Also, rain water may infiltrate the refuse and increase the
moisture content, which in turn increases the rate of decomposition, and
thus the gas production. This condition, occurring in combination with
the decreased permeability of surface soils, can result in significant
seasonal variation in the extent of gas migration. Where a groundwater
table exists beneath a disposal site, It provides an absolute limit to
the depth of gas migration.
The gas produced within a landfill must escape; the geologic-
hydrologic environment and construction of a particular site combine to
determine the direction the gas will flow, either through the cover,
laterally, or In both directions. Uncontrolled relief of the gas may
mean Its release occurs in an undesirable area, leading to environmental
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and hazard problems. Controlled relief means release Is !n a manner
compatible with environmental security and safety.
Placement of a thick, moist, vegetative final cover may act as a
gas-tight lid that forces gases to migrate laterally from the landfill.
If the site is converted into a paved parking lot, this may prevent
gases from venting into the atmosphere.
In 1968, seepage of methane from a landfill caused an explosion In
a National Guard armory in Winston-Salem, North Carolina that took the
lives of three men and seriously injured two others. Two workmen in
Milwaukee were killed when methane seeping into a deep storm sewer
trench ignited. In 1975, small buildings at two separate fills In
Michigan suffered structural damage due to methane explosions, while in
Vancouver, Canada a newly-poured foundation slab was structurally damaged
by an explosion in the underslab air space Initiated by a cigarette.
The list of similar incidents Is certainly much larger and continues to
Increase annually. Law suits are evolving around methane hazard and its
effect on adjacent property value, public safety and health, and on
vegetation stress.
LEACHATt:
Leachate Is liquid which has percolated through solid waste and
emerges from a landfill carrying with it soluble and suspended substances.
However, leachate production may be years in Its Initial showing and is
not always produced from landfills. It requires substantial water
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Infiltration (say 2 Inches of water per foot of refuse thickness) to
produce leachate at all. Leachate production will probably occur when
annual rainfall exceeds 30 Inches, and will probably be of no concern
when less than 20 inches of rainfall occurs per annum.
The sources of water which ultimately produce leachate Include
rainfall which either infiltrates the refuse soil cover or flows off the
surface of the disposal site. Some of the portion which infiltrates the
surface will percolate Into the solid waste below as net Infiltration.
Other sources of water infiltration include runoff from surrounding
land, and water entering through the bottom or sides of the fill. The
moisture created by waste decomposition Is so little as to be of no
Impact. Obviously, liquid wastes placed in the landfill during landfilling
may contribute to leachate production.
The first water entering the solid waste is absorbed much as a
sponge absorbs water. Eventually, however, the solid waste reaches a
level of moisture content known as field capacity. At this moisture
content further addition of water causes leachate to leave the solid
waste. Leachate is formed before the refuse Is fully saturated because
solid waste is not homogeneous, channels exist, and some of the waste
does not absorb water readily. These factors may cause water to con-
centrate in some areas and create leachate even though all portions of
the fill are not at field capacity.
Typically, leachate production should not be noticed until after
the refuse has received at least two Inches of net infiltration per foot
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of refuse thickness. Even then production should be limited, as the
refuse still has the ability to absorb additional water before it reaches
Its maximum degree of saturation. If a landfill is well managed (good
cover application, good drainage, uses Impermeable soil cover, Is dense
and well compacted, etc.), then leachate production may not occur until
well after the site is closed. This statement is applicable even in
a-reas of high annual precipitation, and obviously true, almost without
exception, where annual rainfall Is less than 20 Inches per year.
Although the landfills of the past were principally uncontrolled
dumps and filling took place with little if any technical supervision,
the cases of reported leachate damage are remarkably few. We are aware,
however, of a few serious cases of environmental pollution as reported
In the literature, and in addition must recognize that what was below
ground and never measured may never be known. Today, and in the future,
we will be required to determine the migration or control of leachate
through monitoring systems. We expect that the sound engineering princi-
pals Incorporated into current and future landfill design and operations
will support upgraded performance standards. In some instances this
will mean the leachate is encouraged to move outward from the refuse and
seek attenuation in the surrounding soil and water environment. If the
monitoring data supports the design predictions, then all is well and
good.
A real dilemma may be In the offing as regulatory bodies and dischar-
gers of chemical, toxic, and hazardous wastes apply pressures on landfill
operators to accept these more difficult, non-municipal wastes. The
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operator finds a unique opportunity to Increase revenues at the encourage-
ment of regulator and disposer alike, who judge, rightly or wrongly, the
landfill to be the best repository for these wastes. Now, however,
think what will happen when monitoring data reveals an adverse parameter
performance, and then another and yet another. What then will be the
posture of the regulatory body? The discharger? And not the least, the
public? What can the operator do?
Suppose, however, that the site receiving these wastes is a full
containment site (no leachate migration), and that there Is a continual
building of leachate (net infiltration). Sooner or later the landfill
will be fully saturated and the contained liquid must be properly
handled. Again, the leachate will exhibit those characteristics which
reflect the materials deposited therein. The cost of handling and
treating may in fact far exceed the revenues received when the operator
was thanking the regulatory body and discharger for the short-term
revenue wlndfal1.
The most important effect of uncontrolled leachate migration !s
water quality degradation, but there are other deleterious consequences.
The effect on fish and/or plants in areas contaminated by leachate are
often serious. Visual effects and malodor are two environmental impacts
resulting from leachate.
SETTLEMENT
A sanitary landfill will settle as a result of waste decomposition,
filtering of fines, superimposed loads, and its own weight. Bridging
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that occurs during construction produces voids. As the waste decomposes,
fine particles from the cover material and overlying solid waste often
sift Into these voids. The weight of the overhead waste and cover
material helps consolidate the fill, and this development is furthered
when more cover material is added or a structure or roadway is con-
structed on the fII1.
The most significant cause of settlement is waste decomposition,
which Is greatly influenced by the amount of water in the fill. A
landfill will settle more slowly if only limited water is available to
decompose the waste chemically and biologically. In Seattle, where
rainfall exceeds 30 inches per year, a 20-foot fill settled four feet in
the first year after it was completed. In Los Angeles, where less than
15 Inches of rain falls per year, three years after a landfill had been
completed a 75-foot-high area had settled only 2-3 feet, and another
section that had been 46 feet high had settled a mere 1.3 feet. A
demonstration grant we are currently completing in Sonoma County, Cali-
fornia showed up to 20 percent settlement at the completion of stabiliza-
tion by leachate recirculation. This settlement occurred even though
the refuse was placed at a relatively high density of 1000 pounds per
cubic yard.
Settlement also depends on the types of wastes disposed of, the
volume of cover material used with respect to the volume of wastes
disposed of, and the compaction achieved during construction. A fill
composed only of construction and demolition debris will not settle as
much as one that is constructed of residential solid wastes. A landfill
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constructed of highly compacted waste will generally settle less rapidly
than one that Is poorly compacted. If two landfills contain the same
types of wastes and are constructed to the same height, but one has a
waste-to-cover volume ratio of 1:1 and the other a ratio of '»:!, the one
with the lower ratio will settle less.
Differential settling may form depressions that permit water to
pond and infiltrate the fill. In Houston, Texas it is reported that a
one to two-acre section of a completed landfill dropped one to three
feet overnight. Settling may cause structures on the landfill to sag
and possibly collapse; underground utility lines that serve buildings or
traverse the site may shear. Settlements will continue for many years
after the site Is closed, and may be incident dependent, e.g., a sudden
flood.
EROSION
Erosion results when sheet runoff of a covered landfill is non-
uniform, and when the underlying cover soil is erodable (non-cohesive
soil, devoid of vegetation, loose, etc). Differential settlement due to
the decomposition of refuse material at different rates can lead to the
redirection of surface drainageways which in turn collect water and lead
to erosion of the cover material. The Improper design or placement of
drainage ditches, culverts, driveways, or streets may also lead to
premature erosion of cover material and exposure of refuse. Wind erosion
may also adversely affect the durability of landfill cover and must
therefore be considered among the long-term maintenance problems. Gas
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migration may adversely stress erosion resistant vegetation, thereby
Indirectly fostering erosion.
PROPERTY VALUES
A landfill can Impact significantly on land values in tangible as
well as Intangible ways. The value of a completed landfill may be on
the order of 50 to 80 percent of the value of similar zoned adjacent
property. The reason for the reduction Is obvious: Increased improvement
and maintenance costs.
The Impact on adjacent properties may be far more intangible. The
mere potential of: (1) future malodors appearing' (2) future gas hazard',
andj (3) unsightliness caused by vegetative stress, erosion and grade
changes induced by settlement, are enough to have a negative effect upon
property values.
VISUAL AESTHETICS
Aesthetics, In particular the visual aspects of a completed land-
fill, cannot be Ignored as a potential long-term problem or even as the
cause for a legal complaint.
NEED FOR QUALITY CONTROL
The foregoing discussion identifies the most prevalent problems
which can surface subsequent to closure of a landfill. This Is not
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meant to Indicate that sanitary landfills are not a practical or economic
means for the disposal of wastes. On the contrary, sanitary landfilling
Is the principal means for the disposal of the nation's waste. The
point to be made is that a sanitary landfill requires careful planning
and engineering to control potential problems.
Now let us examine what can be done In the way of preventive or
remedial actions which should be taken to preclude post construction
maintenance, decline in property values, or property damage and litiga-
tion. In each case it will be seen that preventive action taken during
landfill design and construction is less costly than remedial steps
taken after a landfill has been closed.
METHANE GAS CONTROL
There are three basic approaches to the control of methane gas:
(1) control of the production, (2) prevention of migration by means of
Impervious barriers to flow,' and (3) venting.
Controlling rate of production, although technically feasible, is
not practical at present. The future holds promise in (1) rapid sta-
bilization of refuse through leachate recircuiation which will result In
a relatively early cessation of gas production, and (2) exhaust venting
Internally of the refuse limits thus drawing oxygen through the methano-
genlc bacteria environment. Since the oxygen is toxic to these micro-
organisms, this procedure wi11 limit methane production.
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Impermeable membranes consisting of natural clay; plastic, rubber,
or similar film sheet; and asphalt can be utilized to control gas flow.
Soil barriers are most effective when maintained at a high saturation
level. Soils utilized for cover sealing, however, may develop cracks as
a result of drying or large differential settlement occurring across the
surface of the fill. For this reason, the thinner flexible polymeric
membranes or reinforced rubber are often preferred for migration control.
Barriers typically are best implaced during landfill construction, as
subsequent installations are often costly, less extensive than required,
and occasionally impossible to accomplish. During construction, barriers
can be placed to cover the base and lateral surfaces of the fill space.
Installation after fill completion might be limited to trenching in the
area requiring protection and insertion of a membrane into the trench,
followed by backfilling.
Venting systems may be either passive (relying on naturally occur-
ring pressure or diffusion gradients) or induced exhaust (blowers are
utilized to create a pressure gradient), the selection being dependent
on site conditions. The passive systems rely on imposition of material
of high permeability, such as gravel, in the path of the gas flow, the
effect being to present a path for gas flow more conducive to flow than
the surrounding medium, and thereby redirecting flow to a point of
controlled release. These systems usually consist of a gravel blanket
or continuous trench backfilled with gravel. Passive systems are ir.ost
effective In controlling convective gas flow, less so in instances of
diffusive flow. Since most of the flow Is diffusion ralated the designer
must judge the effectiveness of his selection based on the character of
the flow regime.
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Induced flow systems, particularly those employing suitably designed
vertical wells, have proven very effective in the control of lateral
migration,whether convection or diffusion induced. Typically these
systems Incorporate a series of vertical wells emplaced in large diameter
bore holes, not unlike those being considered in gas recovery (for fuel)
systems. Wells are spaced at intervals along the margin of the landfill
requiring protection, either located interior to the limit of fill, or
externally In the surrounding native soils, depending on system require-
ments. The wells are connected by manifolding to a central exhaust
blower which draws gas from the well field. The gas flow in the volume
of refuse or soil influenced by each well is therefore toward the well,
effectively controlling migration. Systems combining both recovery and
migration control should be considered whenever practical.
Gases collected by exhaust systems are generally disposed of by
direct stacking, incineration, or by passage through various sorption
media. Gases from passive vent systems usually are allowed to direct
discharge; in certain cases, the gases are combusted as in "tiki torches."
In all instances, uncombusted gas must be exhausted at a location where
It Is not subject to careless ignition, generally in a protected enclo-
sure, or above normal reach. Direct discharge may release noxious odors
and the designer should always be prepared for a backup burner system to
control odors, if objectionable.
The success of any control system Is measured by a monitoring
system throughout the gas production life of the landfill.
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LEACHATE CONTROL
The objective of any leachate control system is to prevent the flux
of landfill-produced contaminants to the groundwater and/or surface
water regimes. Many soils have an ability to attenuate waste residues
and thus reduce the contaminant flux to the hydrologic system. Where
possible this natural ability of the soil to treat leachate should be
employed. Where compatible with the environment and relevant regulations,
it Is by far the simplest and most economical method of leachate control.
Many fine-grained moderately permeable silt and clay rich soils offer
excellent potential for natural control of landfill-produced contaminants.
The slope of the water table indicates the general direction of
leachate movement. The actual path may be influenced by other factors
such as difference in specific gravity of leachate from water, variations
and/or stratification of earth materials, the topography and elevation
of the top of the zone of saturation, and by external factors such as
streams that intercept the water table, and/or pumping wells. The third
dimension, the vertical component of flow, must always be considered.
Close to streams that receive groundwater discharge there may be an
upward movement of groundwater. In such areas, the natural flow system
controls the movement of leachate - extensive groundwater pollution is
prevented but undesirable quantities of contaminants may reach the
stream.
In situations where natural control systems are deemed to be insuffi-
cient, because of inadequate or poorly understood soil conditions, or
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for other reasons, facilities for leachate containment, collection and
treatment may be developed, and in practice are imperative. Leachate
control can be accomplished by controlling the generation rate and
chemical composition, for example by design of the fill so as to minimize
Infiltration, by recirculation, by control of pH, and by full or partial
containment through the use of liners.
The quantity of leachate produced, and thus the amount requiring
treatment after collection, can be greatly reduced by careful site
design and good management. By using a thick final cover of well com-
pacted clayey soil graded to relatively steep slopes and well vegetated
with erosion-resistant plants, It may be possible to reduce and perhaps
preclude the production of leachate. The ultimate control would be to
eliminate infiltration into the landfill by placement of an impermeable
liner between the refuse and cover soil.
Waste may be deposited upon essentially impermeable in-sltu soil or
bedrock where careful bottom grading directs leachate along the bottom
of the fill to suitable collection facilities. Handling and treatment
of the leachate beyond the collection point requires a site specific
design solution.
In recent years public concern over the pollution potential of
landfill produced leachate has grown tremendously. As a result of this
concern, and because of the difficulty in procuring the most desirable
sites for landfill, there has been an Increasing interest in the use of
Impermeable membranes or liners that will Intercept leachate at the base
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of burled refuse and thus prevent It from entering the soil beneath the
landfill site. Leachate thus intercepted must be collected and removed
for treatment before release Into the environment. A liner can be
employed so ar to utilize land for solid waste disposal that otherwise
may be unsuitable from a hydrogeologic viewpoint. A liner of suitable
material, carefully Installed beneath the entire fill area, is a positive
method of leachate control.
SETTLEMENT CONTROL
\
Subsidence In landfills has been tentatively determined to be a
function of the Initial compaction of refuse materials, compaction of
refuse materials due to surcharge loads, volume reduction caused by
biological decomposition of the organic constituents of the refuse,
volume reduction caused by saturation, the nature of refuse materials
such as compressibility, and volume reduction resulting from removal of
teachable materials. Minimization of heterogeneity may be accomplished
by mixing the refuse with inert material, addition of water to an optimum
moisture content to facilitate compaction, and maximized compaction.
Shredding and baling also contribute to volume reduction and therefore
minimize settlement.
Leachate reelrculatlon can greatly shorten refuse stabilization
time, thereby inducing maximum settlement in minimum time. This approach
lends Itself to early use of the site for development purposes.
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EROSION CONTROL
Erosion control measures include planting vegetation; use of mulches
such as straw, hay, wood chips; soil stabilization, structural coverage,
as well as energy dissipators and rip-rap protection for flowing water.
Planting vegetation is an important and effective method of pre-
venting and limiting erosion, but vegetation alone will not provide
adequate protection on soils that are unstable because of their struc-
ture, nutrient availability, internal water movement, or excessively
steep slopes.
Mulch plays much the same role as vegetation - intercepting rain
and preventing soil displacement by impact and retarding runoff. It
also enhances viability of seedings by conserving soil moisture.
Soil stabilization includes compaction to increase relative density
and the addition of gravel and clay to reduce erodability. Chemicals
may also be added to the topsoil to reduce erosion.
Drainage channels or watercourses with steep gradients should be
lined with suitable structural coverage - sod, concrete, asphalt, rip-
rap, or gunnite.
VISUAL AESTHETICS
landscaping, contouring, and general maintenance procedures are the
i principal means for controlling the appearance of a landfill. In
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addition to being aesthetically attractive, trees can also help prevent
wind erosion.
PROPERTY VALUES
One problem that cannot be fully controlled at this time is the
Intangible problem of the impact of landfills on property values. The
answer to this problem, however, is in the implementation of appropriate
quality control techniques as discussed in the previous paragraphs.
With proper quality control, landfills can become technically sound
products and minimum degradation in property values should result.
CONCLUSION
The major point to be made in all of the foregoing is that a sani-
tary landfill requires careful planning, engineering, and design, plus
sound operation to insure that long-term maintenance problems will not
prove a source of liability. If properly designed and operated, a
sanitary landfill can actually increase the value of surrounding land.
When completed, properly designed and engineered landfill sites can be
converted to community assets as parks, golf courses, green spaces, ski
hills, and other attractive uses. What a community might otherwise
consider an undesirable neighborhood liability can evolve into an attrac-
tive park or, In the case of a commercial/industrial development, a
highly desirable taxable asset.
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ECONOMICS OF LANDFILL LOCATION
BY JOHN W, THOMPSON
OFFICE OF SOLID WASTE MANAGEMENT PROGRAMS
u.S, ENVIRONMENTAL PROTECTION AGENCY
TRADITIONALLY, THE LOCATION OF LAND DISPOSAL SITES HAS
BEEN PREDICATED ON TWO IRRATIONAL FACTORS; "OUT OF SIGHT,
OUT OF MIND" AND "CHEAP LAND HOLDS DOWN DISPOSAL COSTS."
WHILE THESE ATTITUDES HAVE STRONG PUBLIC APPEAL, THE LONG-
RANGE COST MAY BE MORE THAN TAXPAYERS CAN OR SHOULD SUPPORT,
ASSUMING ALL SITES UNDER CONSIDERATION ARE ENVIRONMENTALLY
ACCEPTABLE, RATIONAL DECISIONS AS TO THE LOCATION OF NEW
DISPOSAL SITES SHOULD BE BASED ON AN ECONOMIC APPRAISAL OF
THE LONG-RUM COSTS.
IN RECENT YEARS, MANY COMMUNITIES OPTED FOR NEW SITES
15 TO 50 MILES FROM THE CITY. ALTHOUGH CITIZEN OPPOSITION
AND THE PRICE OF LAND WERE LOW, THE DECISION REQUIRED THE
CONSTRUCTION OF TRANSFER FACILITIES THUS INCREASING CAPITAL
AND OPERATING COSTS. OTHER COMMUNITIES WITH CLOSE IN SITES
ACQUIRED SHREDDING FACILITIES WITH THE IDEA OF INCREASING
THE VOLUME OF SOLID WASTE PLACED IN A SITE. WHILE THIS
DECISION MAY HAVE LENGTHENED THE LIFE OF THE SITE TO SOME
EXTENT IT ALSO INCREASED TOTAL SYSTEM CAPITAL AND OPERATING
COSTS SUBSTANTIALLY.
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RECENTLY, THE OFFICE OF SOLID WASTE MANAGEMENT PROGRAMS
(OSWHP) IN EPA CONDUCTED A STUDY OF LANDFILL, SHREDDER, AND
TRANSFER STATION COSTS. ^ RESULTS INDICATED THE PRICE OF
LAND IS SUCH A SMALL PORTION OF TOTAL DISPOSAL COSTS, THAT
PAYING A VERY HIGH PRICE FOR LAND ADJACENT TO THE COMMUNITY
MAYBE A SOUND ECONOMIC DECISION. THIS IS ESPECIALLY TRUE IF
THE LAND CAN BE ACQUIRED IN LIEU OF TRANSFER OR SHREDDER
FACILITIES.
USE OF SHREDDING OR TRANSFER FACILITIES IS AN INTERMEDIATE
REHANDLING STEP BETWEEN COLLECTION AND DISPOSAL. THE RECENT
OSWMP EXAMINATION OF THE COSTS OF THESE PROCESSES INDICATED
THAT:
• SHREDDING OPERATIONS COST ABOUT $7.46 PER TON OF
SOLID WASTE PROCESSED
• TRANSFER OPERATIONS COST $5.21 PER TON, EXCLUSIVE OF
COLLECTION, AND DISPOSAL COSTS IN 1975.
• THE COST OF LAND WAS LESS THAN 4 PERCENT OF SOLID
WASTE DISPOSAL COSTS BASED ON THE 17 SITES SURVEYED.
• IN MOST INSTANCES PAYING A HIGH PRICE FOR LAND CLOSE
TO THE CENTER OF WASTE GENERATION OR ADDING LINERS
AND LEACHATE CONTROL WILL ADD LESS TO THE COST OF
WASTE MANAGEMENT THAN WOULD INSTALLATION AND OPERATION
OF SHREDDING OR TRANSFER FACILITIES.
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SW DISPOSAL COSTS ARE THE LOWEST COST ITEM IN MUNICIPAL
gOLID WASTE MANAGEMENT
THE FOLLOWING TABLE OF 1975 SOLID WASTE COSTS SHOULD
HELP SUBSTANTIATE THE FACT THAT LAND DISPOSAL IS THE LEAST
COSTLY OPERATION IN SOLID WASTE MANAGEMENT IN MOST COMMUNITIES.
ITEM COMMUNITIES RF.PORTING AVERAGE COST PER TON
COLLECTION 102 $21.OO2
SHREDDING QQ-MILE HAUL) 7 7.46
SHREDDING ONLY 10 5.83
TRANSFER (17-wiLE HAUL) 11 5.21
LANDFILLING MIXED SOLID WASTE W 3.33
LANDFILLING SHREDDED SOLID WASTE 3 1.84
THE 17 LAND DISPOSAL SITES SHOWN ABOVE PLACED AN AVERAGE
OF 380 TONS PER DAY, COSTS RANGED FROM $1.30 PER TON FOR
ONE SHREDDED SITE TO $6.72 PER TON FOR A LOW TONNAGE SITE WITH
HIGH ENVIRONMENTAL STANDARDS. THESE FIGURES INCLUDE LAND
AND DEVELOPMENT COSTS BUT NOT INTEREST.
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AND OPERATING COSTS FOR 17 PERMITTED LAND DISPOSAL SITES
CAPITAL COSTS PER TON PLACED OPERATING COSTS PER TON PLACED
LAND $ .13 LABOR AND FRINGES $1.20
DEVELOPMENT .13 STATIONARY EQUIPMENT .04
STATIONARY EQUIPMENT .01 VEHICLE 0 & M .84
VEHICLES .39 ADMIN. & OTHER .31
TOTAL $ .66 TOTAL $2.39
.66
$3.05
LAND COSTS FOR THE ABOVE SITES AVERAGED 13 CENTS PER
TON OF SOLID WASTE PLACED AND RANGED FROM .02 TO 39 CENTS
PER TON. TYPICAL LAND COSTS REPORTED FOR NEWLY ACQUIRED
LAND AVERAGED ABOUT $2,000 PER ACRE (RANGING FROM $163 TO
$10,600). NATURALLY, THE DEPTH OF THE FILL, AMOUNT OF
COVER, NON USEABLE LAND, AND SOIL COMPOSITION HAD AN EFFECT
ON TONS PLACED PER ACRE. THE 17 SITES AVERAGED 16,400 TONS
OF SOLID WASTE PER ACRE RANGING FROM 4,000 TONS IN FLORIDA
TO 34,000 TONS IN CALIFORNIA.
DEVELOPMENT COSTS ARE ANOTHER IMPORTANT CONSIDERATION
IN LOCATING A SANITARY LANDFILL. IN THE OSWflP STUDY CITED
ABOVE, DEVELOPMENT COSTS FOR DESIGN ENGINEERING, PERMITS,
ROADS, FENCES, LEACHATE COLLECTION, DRAINAGE, VENTING, AND
OTHER ASSOCIATED COSTS AVERAGED .13 CENTS PER TON; THE SAME
AS LAND COSTS. THE DEVELOPMENT COSTS RANGED FROM 0 TO 88
CENTS PER TON. BASED ON DATA COLLECTED, LOW PRICED LAND WAS NOT
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ALWAYS THE MOST EXPENSIVE ITEM IN THE LOCATION OF A SITE.
OFTEN A ROAD COSTING $30,000 TO $150,000 WAS NEEDED. SEVERAL
CITIES REPORTED EXTENSIVE COSTS IN GETTING UTILITIES TO THE
SITE OR HAD A CONSIDERABLE AMOUNT OF DRAINAGE TO DO BEFORE
THE SITE COULD BE OPENED.
VALUE OF LAND IN RELATION TO TRANSFER COSTS. IN RECENT
YEARS, MANY COMMUNITIES HAVE LOCATED SITES AT CONSIDERABLE
DISTANCES FROM THE SOURCE OF WASTE GENERATION. THIS HAS
MADE IT NECESSARY TO INSTALL ONE OR MORE TRANSFER STATIONS
AND A FLEET OF TRACTOR TRAILER TRUCKS FOR MOVING SOLID WASTE
TO THE SITE, |'10ST TRANSFER STATIONS HAVE BEEN JUSTIFIED ON
THE BASIS THAT LOST TIME FOR COLLECTION VEHICLES IN NON
ROUTE ACTIVITIES MORE THAN COMPENSATE FOR COSTS OF OPERATING
A TRANSFER STATION, WHILE MOST TRANSFER STATIONS ARE JUS-
TIFIED, HAULING SOLID WASTE A LONG DISTANCE BY ANY MEANS IS
A COSTLY OPERATION,
AVERAGE HAULING COSTS PER TON WERE ESTIMATED AT $2.70 BASED
ON 10 SITES. THIS INCLUDES DRIVERS AVERAGE WAGES OF $5,00
PER HOUR AND 20 PERCENT FRINGE BENEFITS, ABOUT 52 CENTS OF
THE PER TON COST WAS FOR VEHICLE DEPRECIATION. MOST TRANS-
FER FACILITIES USED TRACTOR TRAILER VEHICLES WITH A 30,000
POUND NET WEIGHT CLASSIFICATION. ON A MILE BASIS, COSTS WERE
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ABOUT $1.36 FOR A 15 TON LOAD OR ABOUT 9 CENTS PER TON MILE.
THIS MUST BE DOUBLED TO COMPENSATE FOR THE ROUND TRIP. THUS,
EACH MILE CLOSER TO THE TRANSFER STATION THAT A DISPOSAL
SITE IS LOCATED REDUCES TRANSPORTATION COSTS BY 18 CENTS PER
TON. IF WE ASSUME A SITE HOLDS, 16,000 TONS PER ACRE, EACH
MILE CLOSER TO THE TRANSFER STATION A DISPOSAL SITE IS
LOCATED WILL REDUCE HAULING COSTS BY $2,280 PER ACRE OF LAND
USED. THIS SAVING IN TRANSPORTATION COSTS COULD BE APPLIED
TO THE PURCHASE OF MORE EXPENSIVE LAND CLOSER TO THE TRANSER
STATION.
ANOTHER WAY TO LOOK AT HOW COSTLY AN INTERMEDIATE
PROCESSING STEP LIKE A TRANSFER AND HAULING OPERATION CAN BE
IS TO ASSUME VERY EXPENSIVE LAND COULD BE PURCHASED WITHIN
THE CITY LIMITS IN LIEU OF A TRANSFER STATION AND LOW COST
LAND IS MILES AWAY. COST SAVINGS OF $5.21 PER TON FOR
OPERATING AND CAPITAL COSTS OF THE TRANSFER FACILITY MULTIPLIED
BY 16,000 TONS PER ACRE WOULD MAKE THE LAND WORTH $83,000
PER ACRE AS A DISPOSAL SITE. SIMILARLY ONE COULD JUSTIFY
TAKING NEARBY LAND WHICH IS LOW PRICED OR SUBMARGINAL, AND
MAKING IT ENVIRONMENTALLY SUITABLE FOR LANDFILLING BY INSTALL-
ING LINERS AND LEACHATE CONTROL IN EXCHANGE FOR A LONG HAUL
OR THE NEED FOR A TRANSFER FACILITY.
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OTHER FACTORS SUCH AS POLITICAL AND ENVIRONMENTAL
CONSIDERATIONS CAN NEGATE THE ARGUMENT FOR DISPOSAL SITES
ADJACENT TO THE COMMUNITY. BUT, PLANNERS AND DECISION
MAKERS SHOULD AT LEAST MAKE AN ATTEMPT TO EVALUATE, ON A
LONG RUN COST BASIS, ALTERNATIVES TO TRANSFER AND LONG
DISTANCE HAULING OF SOLID WASTE BEFORE REACHING A CONCLUSION
ON THE LOCATION OF DISPOSAL SITES,
VALUE OF LAND IN RELATION TO SHREDDING
SHREDDING OR THE GRINDING OF WASTE INTO UNIFORM PARTICLE
SIZE IS ANOTHER ALTERNATIVE STEP FOR REDUCING LANDFILL
(LAND) COSTS. ADVOCATES OF SHREDDING GENERALLY LIST HIGH
COMPACTION, LITTLE OR NO COVER MATERIAL AND VECTOR CONTROL
AS PRIMARY JUSTIFICATIONS FOR SHREDDING. BASED ON THE 1975
OSWMP STUDY OF 7 SHREDDER OPERATIONS, WITH A 21 MILE ROUND
TRIP HAUL TO A DISPOSAL SITE, TOTAL COSTS WERE $7.46 PER
TON, OF THIS AMOUNT, $5.76 WAS FOR OPERATING COSTS AND
$1.70 FOR CAPITAL COST EXCLUDING INTEREST. THE HAULING
COSTS OF $1.47 PER TON ON A 21 MILE TRIP BASIS, INCLUDED
DRIVERS WAGES AND FRINGES AND WERE INCLUDED IN THE OPERATING
COST,
THERE HAS BEEN CONSIDERABLE AMOUNT OF LITERATURE PUB-
LISHED IN RECENT YEARS ON THE USE OF SHREDDING AND HIGH
DENSITY COMPACTION TO EXTEND THE LIFE OF A DISPOSAL SITE.
MOST INFORMATION INDICATES SHREDDING CAN EXTEND THE LIFE OF
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A DISPOSAL SITE BY 25 TO 33 PERCENT WHEN DAILY COVER IS USED
AND UP TO 60 PERCENT IF DAILY COVER IS NOT REQUIRED. HEAVY
DUTY COMPACTORS CAN INCREASE SITE LIFE BY 10-15 PERCENT.
WHILE THESE CLAIMS MAY BE TRUE, IF THE LAND COST is ONLY $
.13 PER TON PLACED, HOW MUCH ADDITIONAL CAPITAL AND OPERATING
COSTS CAN OR SHOULD A COMMUNITY SPEND FOR BETTER UTILIZATION
OF THEIR DISPOSAL SITE THRU SHREDDING AND HIGH DENSITY
COMPACTION? ASSUMING A COMMUNITY CAN EXTEND THEIR SITE
CAPACITY BY ONE THIRD THROUGH SHREDDING, THE VALUE OF THE
LAND SAVED IS WORTH ONLY 6-7 CENTS A TON. ON LAND WORTH
$10,000 PER ACRE THIS WOULD RESULT IN A LAND SAVING OF ONLY
30 CENTS PER TON WHILE COSTING ABOUT $5.83 PER TON FOR
OWNERSHIP AND OPERATION OF THE SHREDDING FACILITY EXCLUSIVE
OF THE HAUL COST.
DISPOSAL OF SHREDDED MATERIAL WAS LESS COSTLY THAN
DISPOSAL OF CONVENTIONAL SOLID WASTE. THREE SITES PLACING
ONLY SHREDDED MATERIAL REPORTED OPERATING COSTS OF $1.32 PER
TON, AND CAPITAL COSTS OF $ .52 FOR A TOTAL OF $1.84 PER
TON. THIS WAS 55 PERCENT LESS COSTLY THAN THE $3.33 FOR
PLACING CONVENTIONAL WASTE. (THESE DATA INCLUDE LAND, AND
EQUIPMENT DEPRECIATION BUT NOT INTEREST). HOWEVER, SEVEN OF
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THE SHREDDER FACILITIES PLACED THE SHREDDED MATERIAL INTO A
TYPICAL DISPOSAL SITE ALONG WITH DEBRIS FROM ALL OTHER SOURCES.
THUS THE ADVANTAGES OF RELAXED STANDARDS FOR COVER MATERIAL AND
VECTOR CONTROL WERE LOST. MOREOVER IN SOME CASES, THE
ECONOMIC ADVANTAGE OF LOWER COSTS FOR A SHREDDED SITE WERE
OFFSET BY THE NEED FOR OPERATING A SECOND SITE FOR NON-
SHREDDED WASTES SUCH AS CONSTRUCTION DEBRIS, INDUSTRIAL
MATERIAL, STUMPS, YARD MATERIAL AND BULKY ITEMS. THE
OPERATION OF A SECOND SITE REDUCED ANY ECONOMY OF SCALE IN
THE UTILIZATION OF EQUIPMENT AND LABOR ASSOCIATED WITH ONE
LARGE DISPOSAL SITE.
ALTHOUGH SHREDDING is A NECESSARY PART OF RESOURCE
RECOVERY, SHREDDING PRIOR TO LAND DISPOSAL IS NOT NECESSARY
AND CAN BE A VERY COSTLY OPERATION. USING A TOTAL CAPITAL
AND OPERATING COST FOR SHREDDING OF $5.83 PER TON LESS $1.49
LOWER LAND DISPOSAL COSTS, THE NET COST OF SHREDDING IS
$4.34 PER TON. ASSUMING THE TYPICAL LAND DISPOSAL SITE WILL
HOLD 16,000 TONS PER ACRE AND THE WASTE WAS NOT SHREDDED,
COST SAVINGS TO THE COMMUNITY WOULD EXCEED $69,000 PER ACRE
BURIED. THIS COST SAVINGS COULD BE USED FOR THE PURCHASE OF
NEW OR ADDITIONAL LAND OR LINERS FOR SUBMARGINAL LAND.
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IN RECENT YEARS MANY COMMUNITIES HAVE BEEN UNDER PUBLIC
PRESSURE TO IMPROVE THEIR SOLID WASTE MANAGEMENT PRACTICES.
IN MANY INSTANCES THEY REACTED BY CONSTRUCTING SHREDDER
FACILITIES AND TRANSFER STATIONS, AND LOCATING LAND DISPOSAL
SITES LONG DISTANCES FROM THE SOURCE OF WASTE GENERATION
WITHOUT CONSIDERING THE LONG RUN ECONOMIC COSTS. IN MANY
INSTANCES (1) PAYING A HIGH PRICE FOR LAND CLOSE TO OR
WITHIN THE CITYj (2) INVESTING CAPITAL IN LINERS AND LEACHATE
CONTROL ON SUBMARGINAL LAND OR (3) ANNEXING LAND TO THE
CURRENT DISPOSAL SITE THRU EMINENT DOMAIN WOULD HAVE BEEN
SUBSTANTIALLY THE LEAST COSTLY ALTERNATIVE ASSUMING ENVIRON-
MENTAL ASPECTS ARE EQUAL.
TOLEDO, OHIO WAS CONFRONTED WITH THE PROBLEM OF LOCATING
A NEW DISPOSAL SITE. AFTER CONSIDERATION OF MANY SITES AND
ALTERNATIVES, TOLEDO ARRIVED AT WHAT WE BELIEVE WAS THE
CORRECT DECISION. THEIR NEW 160 ACRE SITE IS LOCATED WITHIN
THE CITY LIMITS. IT IS SERVED BY TWO MAJOR HIGHWAYS AND 17
ACRES ARE SET ASIDE FOR A SHREDDING FACILITY IF AND WHEN A
MARKET FOR THE WASTE BECOMES REALITY. IN PURCHASING THE
LAND, IT WAS NECESSARY TO ACQUIRE 28 RESIDENCES ON 55 PARCELS
OF LAND. MUCH OF IT THRU EMINENT DOMAIN. AVERAGE LAND COST WAS $LO,600 PER
ACRE. BASED ON AN ESTIMATED PLACEMENT OF 28,000 TONS PER ACRE IN A 35 FOOT
DEPTH, LAND COSTS WILL BE APPROXIMATELY 38 CENTS PER TON.
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THIS IS A VERY LOW SOLID WASTE DISPOSAL COST WHEN CONSIDERED
AGAINST OTHER ALTERNATIVE COSTS IN SOLID WASTE MANAGEMENT.
IN SUMMARY, DECISION MAKERS SHOULD EVALUATE THE LONG
RUN CAPITAL AND OPERATING COSTS FOR ALL PHASES OF THEIR
SOLID WASTE MANAGEMENT SYSTEM IN LIGHT OF THE FACT THAT LAND
AND LAND DISPOSAL OF SOLID WASTE MAY BE ONE OF THE LOWEST
PRICED VARIABLES IN THEIR OVERALL SOLID WASTE SYSTEM.
I/ COST ESTIMATING HANDBOOK FOR TRANSFER, SHREDDING AND
SANITARY LANDFILLING OF ^OLID WASTE, 85 P. Booz
ALLEN AND HAMILTON. AUGUST 1976. PRINTED COPY $5.00
PB-256-WJ-1UP. NATIONAL TECHNICAL INFORMATION SERVICE,
U.S. DEPARTMENT OF COMMERCE, b285 PORT ROYAL ROAD,
SPRINGFIELD, VIRGINIA 22161
2/ EVALUATING THE ORGANIZATION OF SERVICE DELIVERY IN SOLID
WASTE COLLECTION AND DISPOSAL. SAVAS, E.S.j COLUMBIA
UNIVERSITY, OCTOBER 1975.
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GROUNDWATER PROTECTION ISSUES
Eugene A. Glysson
Civil Engineering Department
University of Michigan
Ann Arbor, Michigan
The subject of groundwater protection has become a very
important issue in solid waste management. Various methods
of protection have been described and evaluated.
The various strategies might be summarized as follows:
I. Separation
A. Distance:
This implies physical distance such that the native soil
will have a chance to attenuate the potential pollutants. The
efficiency of such separation is obviously dependent on many
factors among which is the type of soil itself.
B. Barriers:
The implication here is that the barrier be installed on-
site before the waste is discharged. The barrier may consist
of a number of materials that have been very well described by
2
Haxo / among which are:
1. Selected soils
2. Plastic membranes
3. Asphalic derivations
4. Portland cement derivations
II. Monitoring
A. Wells
The use of wells in strategic locations within and around
the periphery of the landfill is a well established practice.
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The detection capability of such a system is very helpful in
giving warnings or alaying fear (whichever is the case) with
respect to the apparent migration of leachate from the refuse
mass.
B. Under drains
With the advent of the wider use of the barriers mentioned
earlier an accompanying system of collection drains is often
considered. The justification for such a system is to:
1. Assist in the detection of a break or leak in the
barrier.
2. To provide a means of collection and extraction
of any potential pollutants before they can migrate
away from the site.
It is the ability to not only detect the presence of a
possible source of trouble but to do something in a positive
way to prevent any subsequent damage or danger that is the
most important feature of an acceptable design.
The attenuation of various metal ions by the soil has been
investigated and discussed by Fuller . In addition to the
heavy metals and other ions mentioned in his investigation
there is the question of the attenuation of some of the chlori-
nated hydro carbons and various pesticides and herbicides which
may be placed in a hazardous waste fill. It would be a rea-
sonable assumption to say that the various factors which were
stated by Fuller would probably apply to these more complex
materials as well. However, considering the risks involved,
we should understand their behavior more thoroughly and addi-
tional research should be conducted on the attenuation and
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migration of these materials.
Much has been reported in the literature on the biologi-
cal activity within the solid wastes placed in a landfill.
Some of this information has been based on research on refuse
placed in a lysimeter where conditions can be monitored and
controlled. Other work has been carried out in landfill cells
in a more natural setting with conditions being monitored but
with less ability to maintain them in a designated condition.
We also have information on sewage sludge digestion both anaero-
bic and aerobic which may or may not be applicable to solid
waste decomposition.
A basic question needs to be considered with respect to
the biological degradation of solid wastes. Under normal con-
ditions this process is a natural one which serves to reduce
the volume of the waste and to return it to a stable form
which possesses less threat to the environment. In the pro-
cess gases and various liquids containing organic acids and
other solubolizing components are formed. These may give rise
to problems of themselves. However, the question I raise is
that of the presence of toxic materials being disposed of along
with the normal mixed municipal refuse. What happens if the
toxic materials interfere with the development of the bio-mass
which is usually counted upon to produce the aerobic and anaero-
bic decomposition of the material to stabilize it? If biologi-
cal action is not materially interfered with it has been shown
by several investigators that the toxic substances are made
much more mobile by the products of decomposition and will mi-
grate much more forcely. It has been recommended therefore
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that toxic substances not be mixed with biodegradable organic
materials in the same location within the sanitary landfill.
III. Construction
In the development of hazardous waste fills, or sanitary
landfills in general for that matter, in some locations liners
have been required. As experience is gained by those who are
using various lining methods their successes and problems should
be brought out for the benefit of all. Haxo has described the
research directed toward evaluating the performance of several
liner types. There is a need for developing a standardized
methodology for testing liners in such a way as to more accurately
predict their performance under expected landfill conditions.
An established set of standards would also allow the prospec-
tive user to specify and subsequently receive a predictable
product.
Due to the limited time wherein data gathering and ex-
perience with various liners has been possible we are unable
as yet to predict accurately the life of such liners. However,
based on the knowledge that plastics have a long life in land-
fills there is every confidence that several liner materials
will provide the protection necessary. As practioners we
should ask for as candid a report on the application of these
methods to be made public in as short a time as possible.
We have long been accustomed to being governed by various
regulations set forth by established regulatory agencies at
all levels. The requirements as set forth in these regulations
are usually set at such a level as to provide the necessary
protection or performance in the best judgment of the group
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formulating the regulation. This minimum requirement is often
translated into the maximum provided without regard to the
possibility that corrective measures that may be required later
may be much more inconvenient and expensive than some foresighted
additional provisions beyond those required being provided at
an earlier time.
Such a precautionary situation may be illustrated in con-
junction with the problem of gas (CH.) migration from a land-
fill. It is most certainly cheaper to install gas barriers and
the necessary venting prior to completing the landfill construc-
tion than to have to return to the site in an emergency situa-
tion to correct a problem which has subsequently developed.
We should continue to request and support research on the
conditions which influence and determine the production and
migration of gas so that the need for protective measures can
be more accurately anticipated and the necessary precautionary
measures taken before damage or injury occurs.
Fuller has made mention of the use of some natural ma-
terials such as nut shells for the initial fixation of certain
heavy metals. There are other natural materials such as tree
bark or wood chips which are resistant to degradation and con-
tain lignon that should have an attraction for heavy metals
which might be useful for such a purpose. It should be noted
that these materials have a specific retention capacity and
when that is exhausted they will no longer retain more metals.
The quantity of these natural materials necessary, therefore,
must be determined based on the anticipated amount of heavy
metals to be attenuated from the leachate expected to be
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generated from the material in the landfill. Any method which
is successful in reducing the amount of leachate will assist in
prolonging the time of effective attenuation.
In conclusion it is my observation that the field of solid
waste management is moving rapidly towards a much more sophisti-
cated level where a great deal of technical information is re-
quired. The only way that this type of information can become
widely enough available to all who need it is for those who are
in a position to gain it through practice or research to pass
it along freely through organizations such as the NSWMA.
REFERENCES
1. Fuller, W. H., "The Importance of Soil Attenuation for
Leachate Control," Proceedings 5th National Congress
NSWMA, Dallas, December, 1976.
2. Haxo, H. E., Jr., "Liners-Viable Options and Their Appli-
cations, " ibid.
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EFFECTIVE STATE PROGRAMS
-------
THE IMPORTANCE OF AN EFFECTIVE STATE SOLID WASTE
MANAGEMENT PROGRAM
William G. Bentley
Director, Vice President.
Division of Solid Waste Management Association of State and
New York State Territorial Solid Waste
Department of Environmental Management Officials
Conservation
The need for capable systems of management for solid wastes
Is finally being realized by the people of our country. The
"findings" of the U.S. Congress and the developments In every
state are proofs that these activities are properly located In
state government. These recognized needs, findings, and devel-
opments acknowledge the importance of an effective state solid
waste management program.
The elements in consideration here are: Ij Is It Important
(of much significance or consequence) that we have an effective
(adequate to accomplish the purpose) program for the management
of the detritus from our effluent society ? and 2) Is the state
somehow the best suited or most appropriate level of government
to conduct such an Important function? Let's begin with whv
it's important to have an effective solid waste management program
tho, it hardly seems necessary for the group assembled at the
Filth National Congress on Waste Kanagrnent.
Proper management of solid wastes Is a requirement for our
national well beln?. There Is sufficient evidence at hand to
recognize that Improper practices In the solid waste field en-
danger human health. We know of the environmental degradation
that results from solid waste Incorrectly managed. And, further,
we now appreciate the waste of resources and energy which we
have allowed with our "throw away" life style.
We have, as a nation, somewhat belatedly come to recognize
the vast quantity of material that is discarded. Whether you
use five pounds per person per day, a thousand tons per person
a year, Include or exclude certain sources, the sheer mass Is
staggering. Just to accomodate this pile we are using space or
acreage that In most instances could be better used in other
ways. The successes in air and water pollution control are
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adding to the solid waste problem. Things that used to go up
the stack or down the drain are commonly special problem addi-
tions to the land disposal burden.
Incineration of the combustible part of the waste stream
has been a serious air pollutor which requires large capital
outlays to correct. The production of leachate from dumped or
buried trash is a well recognized threat to ground and surface
waters. Methane migration from landfills is a continuing and
perhaps, increasing problem. Since open burning has been
stopped to protect air quality more organic material is de-
composing in landfills increasing the possibility of the haz-
ards of uncontrolled gas migration.
Where the methane can be captured it can be a useful re-
source. This idea of recovering resources is only scratching
at the surface of its potential, however. The big picture is
one of tremendous waste - of resources and energy. A country
made great, in large part, by seemingly boundless resources
and cheap energy can no longer afford the throw away style of
life. We are running out of domestic sources. Importing more
and adversely effecting the nation's balance of payments. The
costs, the savings to be realized, the tons of materials,
dollar values, etc. etc. are too familiar to this audience to
need repeating here.
Enough has been said, where it probably needed no re-
minder, about the importance of an effective solid waste man-
agement program. Health, environment and economy require it.
The element perhaps less accepted and certainly not as abun-
dantly reviewed in literature, press and professional con-
ference Is the appropriateness of the concentration of program
effort at state level.
Last year, at the Fourth Congress, Moses HcCall in his re-
port on "The Role of the State in Solid Waste Management" said
"the state level this is 'where it's at' program wise". He
further observed that state governments have the obligation of
assuring that local governments provide for efficient, en-
vironmentally sound solid waste services for their inhabitants,
either by the public or the private sector.
There are a tremendous number of local governments. In
New York State, for example, there are approximately 1600 units
of local government. Most local governments represent small
populations, limited territories, narrow economic bases and fre-
quently, part time government. They most commonly have neither
resources or capacities to carry out an effective solid waste
management program within their own jurisdiction.
At the opposite end of the government scale is the Federal
establishment. The Federal government has provided a very
limited solid waste management program, especially as compared
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to their entry into air and water pollution control activities.
This is quite appropriate in recognition of the relative
uniqueness of the states. Their variation in size, physical
land characteristics, geology, economic development, and popu-
lation distribution; all of which Influence solid waste man-
agement, point to the level below the Federal as most appro-
priate. This also agrees with the concept that governemnt
should be as close to the governed as the desired effect will
allow.
Further support for keeping the management program below
the Federal level deriveu from the nature of the solid waste
problem in as much as it doesn't commonly accumulate to become ar
Interstate and international problem as Is often the case with
air and water pollution. In apparent, recognition of these sev-
eral arguments the Congress in Its "findings" in the Resource
Conservation and Recovery Act of 1976 said "—. the collection
of and disposal of solid wastes should continue to be primarily
the function of State, regional and local agencies ".
There is a strong theme throughout PL94-580 in support of
State solid waste management programs. The appearance of such
terms as "providing technical and financial assistance to State
and local government", "Authorization of State Programs", and
"Authorization of Federal Financial Assistance" are Indicators.
The amounts of the authorized funds for support of State pro-
grams and planning Is adequate proof that the Congress intends
to create effective solid waste management programs at the
state level.
To be effective the programs must provide results. They
must safeguard the health and welfare of the people, protect
the environment and conserve and recover resources and enercy.
It requires complete programs to accomplish such difficult ptoals.
The complete program regulates, assists and lea'l^. State pro-
grams must Include these functions to achieve results.
The USEPA "Solid Waste Management Strategy" recognizer
the importance of effective State solid waste management pro-
grams. In Mr. Train's letter of October 31. 197''* introducing
the strategy a?id included in the document vi<3 says;. '' A fur-
ther element which we believe Is Integral to a viable waste.
management and resource conservation program is n strong and
effective State and local program". And further, he states,
"Greater attention by EPA will be required to assist Statca
and local governments ". The Strategy itself, makes the
statement,."This strategy relies heavily on the States". The
strategy document and Mr. Train's letter say that liPA Is
attempting to "strengthen the State role" and "will assist
States In developing their programs".
Testimony Is support of the need for effective solid
waste management and recognition of the appropriate role of
the State is provided by the following summary comments.
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Ten years ago only two states had administrative programs in
solid waste; now all do. That all the States have reccnized
and accepted this responsible role is significant. These
state programs could not have come to pass in our democratic
system without support of the people, Including local govern-
ment entities which by their support have placed themselves
under the jurisdiction of the state program. The United
-States Environmental Protection Agency in its "Solid Waste
Management Strategy" and that Agency's Administrator,
I'ir. Russell Train, recognize the importance of the State pro-
grams and declare the intention to assist and to strengthen
the role of the State. And, finally, in both Importance and
time, the United States Congress, has passed a progressive
act PL9^-580. which directs the intention of the Federal Gov-
ernment to support and assistance of State programs for solid
waste management.
The urgency for adequate means and mechanisms to be brought
to bear on the solid waste management problem Is not debatable.
We all recognize the significance to human health, environ-
mental protection and resource conservation. We know that
Federal, State and local governments each have Important func-
tions In the solid waste management task. Each has a piece of
the action. The starring role, however, as we have now seen,
is actually and appropriately being played by the State.
In summary, the importance of an effective state solid
waste management program is substantial, is recognized and is
being supported by words, deeds and dollars.
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GOVERNMENT RESOURCE RECOVERY PLANS
-------
RHODE ISLAND SOLID WASTE MANAGEMENT CORPORATION
TOWN HALL PRESENTATION QUESTIONNAIRE RESPONSE
Considerations for implementing resource recovery in Rhode Island
I. Material supply
A. Tonnage-We are presently considering a 1200 ton per day
design figure.
B. Collection-Each jurisdiction in the state is responsible
for the collection of its own raw solid waste.
The Solid Waste Management Corporation has
no authority to involve itself in the collection
of waste.
C. Deliveryof solid waste to the facility- The Corporation
will seek binding contracts with municipalities to guarantee
tonnage to a resource recovery facility.
D. Waste Characteristics-The waste to be delivered to the
facility will not have any special characteristics that
should be noted.
II. Facility Fundina
A. Financing Options - -The Corporation can employ a variety
of funding options including revenue bonds, private
capital, and other approaches. We cannot, however, employ
general obligation bonds.
B. Indebtness Limitations-No such limitations are imposed
in our legislation.
III. Economics of Existing Disposal Methods
A. Operating costs-The Corporation does not at present
operate any facility.
B. Affect of Existing Disposal Economics-Rhode Island probably
enjoys the cheapest landfill operating costs in this part
of the country. This is attributable to the competitive
nature of the private landfill business in the state. We
feel, however, that the remaining life of the existing
privately owned landfills is a key factor. The Corporation
was created by the state and given its mandate to establish
a statewide resource recovery system because it is foreseen
that landfilling cannot be considered a long term solution.
There is only one operating municipal incinerator in the
state, and the costs of operating this facility are thought
to be in excess of $10 per ton.
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TOWN HALL PRESENTATION QUESTIONNAIRE RESPONSE (Cont.)
C. Remaining Years of Use of Existing Facility-Our estimate
of the remaining life of the landfills presently approved
by the Health Department, is 5 to 7 years. This could be
optimistic, however, as environmental standards become
more stringent and more rigidly enforced.
D. Environmental and Other pressures affecting existing
disposal methods - The state health department has
recently enacted a new licensing program which will place
more stringent controls over the operation of disposal
facilities. It should also be noted that several muni-
cipalities have enacted local ordinances prohibiting
importation of out-of-town waste, thus limiting the
regional use of state approved landfills in several
instances.
IV. Resource Recovery Systems Choices
A. At present we have not eliminated any significant
technology for consideration in our R.F.P.
V. Energy and materials markets
A. Markets identified based on preliminary evaluation of
our market study results indicate that there is a strong
market possibility for steam, pyrolysis gas and oil,
and electricity. The potential market for refuse derived
fuel in simple or processed form is still being explored.
B. Potential Markets for Materials-In the same manner we
feel that there is a good potential market for light and
heavy ferrous metals, and aluminum and other non-ferrous
metals. No determination has as yet been made regarding
glass, paper fibers or other materials.
VI. Other institutional, legal concerns
A. Institutional-Legal Concerns-
Under Section 13 of the legislation establishing the
Solid Waste Management Corporation, any municipality
in the state that seeks to dispose of its municipal
waste beyond its own borders must use a facility or
arrangement designated by the Corporation. The Corpora-
tion has already started exerting this control over
the disposal of waste, and is presently negotiating
contracts with 6 municipalities whose wastes are being
sent to a privately owned landfill under the auspices
of the Corporation. Through this program we are now
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TOWN HALL PRESENTATION QUESTIONNAIRE RESPONSE (Cont. )
B.
collecting a surcharge from these municipalities.
Contract Period-The Corporation can legally enter into
long torm contractual commitments.
C. The st;
is a qiiasi-public state agency and as such does act for
the State. The Corporation's plans, as is the case with
any stcite agency, must be reviewed in terms of compliance
with an overall State Guide Plan.
te role-The R.I. Solid Waste Management Corporation
:kam
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Middlesex Countv, New Jersey
RESOURCE RECOVERY FACT SHEET
BACKGROUND
MIDDLESEX COUNTY'S ACTIVE INVOLVEMENT IN SOLID WASTE MANAGEMJENT
BEGAN IN 1972 WHEN THE COUNTY PLANNING BOARD OBTAINED A GRANT FROM
THE U.S. ENVIRONMENTAL PROTECTION AGENCY TO PREPARE A COMPREHENSIVE
SOLID WASTE MANAGEMENT PLAN AND PROGRAM FOR THE COUNTY.
REFUSE QUANTITIES!
IN 1975
OVER 1 MILLION TONS OF SOLID WASTE WERE GENERATED IN
MIDDLESEX COUNTY.
1.7 MILLION TONS WERE DISPOSED OF IN MIDDLESEX COUNTYi
40X IMPORTED FROM OUTSIDE OF THE COUNTY, INCLUDING 300,000
TONS OF REFUSE FROM NEW YORK CITY .
eox OF THE COUNTY'S REFUSE is FROM INDUSTRIAL SOURCESI
40X IS FROM MUNICIPAL (HOUSEHOLDERS, ETC.) SOURCES.
MIDDLESEX COUNTY is THE 2ND LARGEST REFUSE SHED IN NEW
JERSEY, AFTER THE HACKENSACK MEADOWLANDS.
POPULATION GROWTH, INCREASED EMPLOYMENT, INCREASED REFUSE
IMPORTS WILL RAISE THIS DISPOSAL FIGURE TO OVER 2.5 MILLION
TONS/ YEAR, OR OVER 8,000 TONS/DAY.
COSTSi
IN 1975
- THE COUNTY'S MUNICIPALITIES AND INDUSTRIES SPENT APPROXIMATELY
tZO-SS MILLION ON REFUSE COLLECTION AND DISPOSAL.
80X + FOR COLLECTION AND HAULINGi LESS THAN 20X FOR DISPOSAL.
BY 19B5
- THESE COSTS MAY DOUBLE TO $50 MILLION ANNUALLY.
REMAINING DISPOSAL CAPACITY AND COSTS
* AT PRESENT MIDDLESEX COUNTY CONTAINS B REGIONAL-SCALE LANDFILLS
AND 10 SMALL MUNICIPAL-TYPE DISPOSAL SITES.
* FIVE OF THESE SITES (FOUR PRIVATE) RECEIVE SOX OF THE TOTAL
REFUSE DISPOSED OF IN THE COUNTY.
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* BY 1980, THREE OF THESE, INCLUDING THE COUNTY'S LARGEST LANDFILL,
WILL EXHAUST THEIR PRESENT CAPACITY.
* BEFORE 1985 ONLY ONE OF THE COUNTY'S EXISTING REGIONAL LANDFILLS
WILL REMAINi ALTHOUGH THE REMAINING CAPACITY OF THIS SITE IS
EXTENSIVE, THIS SINGLE SITE WILL NOT BE ABLE TO ACCOMODATE
THE REFUSE REQUIRING DISPOSAL IN 1985.
* AS A RESULT, FOUR NEW LANDFILLS CONTAINING OVER 600 ACRES OF
LAND WILL BE NEEDED IN THE COUNTY BY 1985. BY THE YEAR 2000,
13 NEW LANDFILLS CONTAINING A TOTAL AREA OF ALMOST 2,000 ACRES
WILL BE NEEDED TO MEET THE COUNTY'S REFUSE DISPOSAL NEEDS.
* ALTHOUGH IMPROVED OPERATING PRACTICES AND INCREASED DESIGN
HEIGHTS (TO 60 FEET) MAY REDUCE THE NUMBER OF DISPOSAL SITES
AND TOTAL ACREAGE REQUIREMENTS SOMEWHAT, THE SITES THAT WILL
OPERATE WILL BE MUCH LARGER IN AREA AND OPERATING LEVELS THAN
ANY PRESENTLY IN OPERATION IN THE STATE.
* LAND FOR THESE NEW SITES WILL HAVE TO BE FOUND NOT FROM
MEADOWLANDS AND OTHER ''UNUSABLE1' AREAS, BUT FROM PRIME
INDUSTRIAL AND COMMERCIAL LAND NEAR REGIONAL HIGHWAYS.
* THESE SITES WILL ALSO BE LOCATED IN LESS DEVELOPED SUBURBAN
AREAS REMOTE FROM CENTERS OF REFUSE PRODUCTION. AS A RESULT,
HAULING COSTS WILL GO UP AND SO WILL THE COST OF ACQUIRING,
DEVELOPING AND OPERATING TRULY SANITARY LANDFILLS. THE
POTENTIAL IMPACT OF NEW REGIONAL LANDFILLS ON COMMUNITY
DEVELOPMENT, ENVIRONMENTAL QUALITY AND LOCAL TRANSPORTATION
PATTERNS COULD ALSO BE SUBSTANTIAL.
THE PROSPECT OF THIS TYPE OF ''MAXIMUM LANDFILL STRATEGY1' IS
NOT APPEALING TO OUR BOARD OF FREEHOLDERS AND OTHER PUBLIC OFFICIALS
IN MIDDLESEX COUNTY.
RESOURCE RECOVERY
FORTUNATELY, THE PLAN ALSO CONCLUDES THAT ANOTHER MORE WORKABLE
ALTERNATIVE EXISTS - RESOURCE RECOVERY.
* THE SOLID WASTE DISPOSED OF IN MIDDLESEX COUNTY THIS YEAR
CONTAINS THE ENERGY EQUIVALENT OF OVER 2 MILLION BARRELS
OF FUEL OIL.
* IT ALSO CONTAINS ENOUGH FERROUS METALS TO SUPPLY A SMALL
STEEL MILL FOR A YEAR.
* IT CONTAINS LARGE QUANTITIES OF NON-FERROUS METALS, SUCH
AS ALUMINUM AND BRASS, AND NEARLY 30,000 TONS OF GLASS.
* AT PRESENT FUEL PRICES THE ECONOMIC VALUE OF THE COUNTY'S
MUNICIPAL REFUSE ALONE IS OVER *8 MILLION PER YEAR. IF
WE ADD CREDITS FOR THE ''NON-DISPOSAL" OF THIS REFUSE, ITS
VALUE INCREASES TO OVER $9 MILLION PER YEAR.
* THESE ENERGY RESOURCES AND RAW MATERIALS ARE VALUABLE AND
SHOULD NOT BE LOST. -407-
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THE PLAN
* IN RESPONSE, THE PLAN RECOMMENDS THE DEVELOPMENT OF A MIXED
SYSTEM OF RESOURCE RECOVERY FACILITIES AND SANITARY LANDFILLS TO
RECOVER THE MAXIMUM FEASIBLE QUANTITY OF ENERGY AND MATERIAL RESOURCES
CONTAINED IN THE COUNTY'S SOLID WASTE AND PROVIDE SAFE. SANITARY AND
ECONOMICAL DISPOSAL OF THOSE MATERIALS THAT CANNOT BE RECOVERED.
* SPECIFICALLY, THE PLAN RECOMMENDS THE DEVELOPMENT OF 2-3
LARGE-SCALE RESOURCE RECOVERY FACILITIES IN THE URBAN PORTIONS OF OUR
COUNTY BY IQBO-SS AND THAT THIS SYSTEM BE EXPANDED TO THE RAPIDLY
GROWING SUBURBAN AREAS AS SOON AS POSSIBLE THEREAFTER.
* EACH OF THESE INITIAL FACILITIES WOULD PROCESS 1,000 - 1,500
TONS/DAY OF SOLID WASTE AND MAY COST APPROXIMATELY $30 MILLION EACH.
* BY 1981 AS MUCH AS 60X OF THE SOLID WASTE DISPOSED OF IN THE
COUNTY COULD BE PROCESSED FOR RESOURCE RECOVERY.
* INCREASED ENERGY PRICES AS WELL AS THE INCREASED COST OF NEW
LANDFILLS WILL MAKE RESOURCE RECOVERY COMPETITIVE WITH THESE CONVENTIONAL
DISPOSAL METHODS BY 1980.
* THE PLAN RECOMMENDS THAT THE FACILITIES BE CONSTRUCTED AND
OPERATED BY PRIVATE INDUSTRY AND THAT A COUNTY IMPROVEMENT AUTHORITY
BE CREATED TO FINANCE THEM.
THE PLAN WAS COMPLETED IN DECEMBER 1974 AND ACCEPTED BY OUR BOARD
OF FREEHOLDERS IN MARCH 1975. SINCE THAT TIME A NUMBER OF IMPORTANT
STEPS HAVE BEEN TAKEN TOWARD THE IMPLEMENTATION OF THIS PLANi
i) THE DEPARTMENT OF SOLID WASTE MANAGEMENT PROGRAMS WAS ESTABLISHED
IN APRIL 1975. THE DEPARTMENT is DIVIDED INTO THREE PROGRAM AREASI
RESOURCE RECOVERY, HAZARDOUS WASTE MANAGEMENT AND TECHNICAL ASSISTANCE.
2) A PERMANENT POLICY ADVISORY COMMITTEE ON SOLID WASTE MANAGEMENT
WAS ESTABLISHED IN MAY 1975. THIS GROUP CONSISTS OF LOCAL ELECTED
OFFICIALS, REPRESENTATIVES OF THE PRIVATE SOLID WASTE INDUSTRY, THE
REGION'S INDUSTRIAL WASTE PRODUCERS, ENVIRONMENTAL GROUPS, AND REPRE-
SENTATIVES OF THREE ADJACENT COUNTIES. THIS GROUP ADVISES THE FREEHOLDER
BOARD AND OUR DEPARTMENT ON ALL ASPECTS OF SOLID WASTE MANAGEMENT
PLANNING AND PROGRAMMING IN THE COUNTY.
3) THE COUNTY APPLIED FOR AND WON IN JULY 1975 AN ENERGY RECOVERY
IMPLEMENTATION GRANT FROM THE U.S. EPA TO BEGIN TO IMPLEMENT THE RESOURCE
RECOVERY PORTION OF THE PLAN. THE FOLLOWING PROGRAM ELEMENTS WERE
INCLUDEDi
- A DETAILED ANALYSIS OF THE MARKETS FOR RECOVERED ENERGY AND
MATERIAL PRODUCTS.
- A DETAILED ECONOMIC, ENGINEERING AND ENVIRONMENTAL ASSESSMENT
OF EMERGING RESOURCE RECOVERY TECHNOLOGIES.
- AN ANALYSIS OF ALTERNATIVE FINANCIAL AND MANAGEMENT APPROACHES
INCLUDING THE QUESTION OF PUBLIC OR PRIVATE OWNERSHIP.
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- AND A DETAILED SITE SURVEY
*) A PROGRAM MANAGER FOR RESOURCE RECOVERY, OR. EDWARD JABLONOWSKI,
WAS EMPLOYED IN JULY 1975. IN AUGUST OF THAT YEAR A CONSULTANT, ROY F.
WESTON, INC., WAS SELECTED BY THE PAC AND CONFIRMED BY THE FREEHOLDER
BOARD TO ASSIST IN THE PROGRAM TASKS.
5) A DETAILED REQUEST FOR SYSTEMS DEVELOPMENT PROPOSALS WILL
BE ISSUED IN LATE 1976 AND THE INITIAL SYSTEM(S) SELECTED IN MID-1977.
6) THE FIRST RESOURCE RECOVERY FACILITY IN THE COUNTY MAY BE
UNDER CONSTRUCTION IN THE NORTHERN AREA OF THE COUNTY BY 1978 AND IN
FULL OPERATION BY 1980-81.
7) THE POSSIBILITY OF COMBINING THE RECOVERY OF ENERGY RESOURCES
FROM MUNICIPAL REFUSE AND THE DISPOSAL OF SEWERAGE SLUDGE FROM THE
MIDDLESEX COUNTY SEWERAGE AUTHORITY AT A FACILITY IN THE CENTRAL AREA
OF THE COUNTY is CURRENTLY BEING STUDIED, UNDER CONTRACT, BY PROFESSOR
HELMUT SCHULZ OF COLUMBIA UNIVERSITY.
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RICHMOND METROPOLITAN AREA RESOURCE/RECOVERY PLAN
by
C.F. Wilkinson, P.E.
Director of Public Works
City of Richmond
and
M.E. Fiore, P.E.
Virginia Branch Manager
Roy F. l/eston
BACKGROUND
The City of Richmond, as well as many other local ities'throughout the
country, is attempting to solve two problems, disposal of solid waste and
conserving natural resources, with one decision. Richmond hopes to do
this by burning solid waste to generate steam and then recovering ferrous
and non-ferrous metals from the incinerator's residue.
The Richmond Metropolitan area (Figure 1) has a population of over 500,000
people living in the City of Richmond and the separate counties of Henrico
and Chesterfield. A diversified industrial and commercial base supports
this population and has resulted in continued strong growth and develop-
ment in the region.
As the State Capital, the City is the center of the State political scene.
It is located almost midway between Washington, D.C. and the Morfolk-Tide-
water areas - - two of the fastest growing areas in the country. The City
has established itself as a strong and progressive industrial and financial
center. While considered by many as the tobacco capital of the world, the
City has a diversity of industrial and commercial activity which has con-
tributed to Richmond's reputation as a recession-free City. In addition
to stable industries, $200 million dollars of new construction is undei—
way in the Richmond area, including a $50 million dollar Federal Reserve
Bank. These factors added to the approximately 60,000 government employees
who work in the Richmond area help to create a financially secure and stable
area.
The pressures of growth have had their impact on solid waste management
in the area. Although sanitary landfills have served the area well in the
past, their capability for future disposal is limited. Currently, three
landfills are operated by the City of Richmond, two by the County of Henrico
and two by the County of Chesterfield. Sanitary landfill ing has been and
is the principal method of disposal in this area. Consultants estimate
that present landfills will be depleted in ten to fifteen years (Figure 2)
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FIGURE 1 RICHMOND METROPOLITAN AREA
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asndau SNOJ.
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and that potential additional space will be depleted shortly thereafter
because of the projected increase in volume of solid waste. Restrictions
on available sites, limitations on potential sites, and increased environ-
mental and operating costs are eroding the usefulness of sanitary land-
filling as the sole method of disposal in the region. This is particularly
true in the long run.
TASK GROUP FORMED
The Richmond Metropolitan Area can ill afford to face further years without
a solution to the solid waste problem. To provide a permanent, long range
plan, the Solid Waste Utilization and Task Group was formed in 1973, re-
presenting the City and two counties in the region plus the Commonwealth
of Virginia; the Virginia Electric and Power Company; Reynolds Metals Com-
pany; and Wheat, First Securities, Inc. The group has embarked upon a
program to find and implement solutions to the area's solid waste problems.
The formation of the Task Group alone indicates the significant local com-
mitment that exists within the region. To reinforce that commitment, the
Task Group obtained a pledge of funds from the local governments to initi-
ate the Resource Recovery Program.
One of the first tasks of this group was to visit other cities (such as
Nashville and St. Louis) with Resource Recovery Projects. After observing
these operations, a subcommittee of the Task Group was assigned to prepare
a request for proposals to be forwarded to consultants with experience
in Resource Recovery. This work was accomplished, and the proposals were
received in the fall of 197*1 from eight consulting firms. After detailed
analysis and discussion, Roy F. \)eston, Environmental Consultants-Designers,
was selected for the Phase I Study. Actual work began in June 1975.
FUNDING
The Solid Waste Program was divided into several phases with Phase I being
totally funded by the local governmental agencies participating in the Pro-
gram (see Figure 3). During its Phase I effort, the City, in behalf of
the Task Group, applied for and received a federal grant to finance a con-
tinuation of the program, Phase II. The Task Group felt especially for-
tunate In receiving this grant because only seven other cities received
grants from EPA to investigate implementation of an energy recovery systems.
Work of Phase I was initiated in June 1975 and was essentially completed
in Hay 1976. Phase II of our program is now underway, and we anticipate
completion by mid-1977. The total cost of Phase I and Phase II will be
$118,000.
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PHASE I — PROGRAM OUTLINE
The Phase I work plan included collection and validation of all existing
field data, field evaluation of existing systems, in-depth interviews with
local officials, and discussions with local operating agencies and State
regulatory agencies to permit the project team to become familiar with the
existing solid waste system in the area. Existing State and local regu-
lations, ordinances, administrative structures, the legal framework, and
unique social, economic, and political character of the area were reviewed.
Available markets for by-products generated by a resource recovery program
were assessed, concentrating on potential users of secondary materials,
particularly paper, glass, ferrous and non-ferrous metals. A review of
energy and fuel needs in the metropolitan area, including an inventory of
existing facilities for power generation, fuel storage and distribution,
and major users of both fuel and energy, was performed. Using this informa-
tion, processing alternatives were identified and evaluated using the present
system of sanitary landfill ing and its potential for the future as the basis
for economic comparison. The total evaluation included the cost and facility
requirements of waste transportation and waste transfer as well as the pro-
cessing and disposal for it.
PHASE I—SURVEY RESULTS (Table 1}
The materials and energy survey indicated that local and regional markets
did exist for products produced from a potential Richmond area Resource
Recovery system. Letters of interest were received from local materials
markets indicating interest in ferrous and non-ferrous metals as well as
in paper. (See Figure k.) No local market for glass recovery was indi-
cated, other regional markets outside the region are available and may be
developed as part of a subsequent phase.
A detailed energy market survey was completed using questionnaires and
interviews to establish intent and interest. Figure 5 shows the scope
of the energy markets we sought.
The Energy Survey indicated strong interest by industrial and utility or-
ganizations in purchasing a competitively priced gaseous or liquid fuel;
electricity and steam are also saleable commodities. A solid refuse fuel
(RDF) proved to be the least desirable of all potential energy or fuel
rorns for our local markets. Required equipment modifications, storage
and handling costs, and air pollution control concerns all may be reasons
for this lack of concern.
TECHNOLOGY ASSESSMENTS
An assessment of the existing technology was prepared for the Task Group
to identify technical options which offer potential for the region. Tech-
nical options capable of producing energy and materials that were saleable
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FIGURE 5 FUTURE WASTE MANAGEMENT SYSTEM WITH
SANITARY LANDFILLING AND ENERGY RECOVERY
-418-
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to the local markets were emphasized. A comparison of options was made,
based upon market compatabi1ity, demonstrated reliability, full scale
operation, capital and net operating costs, environmental concerns, and
applicability to the local situation. Technologies evaluated included
energy recovery incineration, pyrolysis, preparation and sale of an RDF,
materials recovery, and alternative methods of land disposal, including
shredding and baling of refuse.
Based upon reliability, technical soundness, and cost, we determined that
steam produced by energy recovery incineration should be the leading can-
didate for implementation. Three markets for this steam exist in the
metropolitan area and are currently being studied. These markets are the
Richmond Downtown Steam Loop, an industrial complex south of the regional
area, and the Chesterfield Power Station of the Virginia Electric and Power
Company (VEPCO). The Downtown Steam Loop and the industrial complex offer
the best potential for long term implementation, while the power station
offers a market with declining needs because of VEPCO's conversion from
fossil-fired to nuclear power plants.
It should be noted that comparing energy recovery alternatives with sanitary
landfill ing still shows significant economic advantages for landfill ing.
The problem with the availability and location of landfill sites, however,
would indicate that the selection of a waste menagement system cannot be
made solely on .the basis of costs. For that reason, the regional study
to implement a resource recovery system is still underway. Regardless of
what system is used, however, sanitary landfilling will still be a function-
ing part of any solid waste management system. Figure 5 indicates the re-
gional sanitary landfill needs if energy recovery can be implemented success-
fully.
ENERGY MARKET DEVELOPMENT
One of the two energy markets which appears most feasible is the Downtown
Steam Loop. The Steam Loop in downtown Richmond, presently served by the
Medical College of Virginia (MCV) power plant, has a seasonal steam demand
that varies from approximately 20,000 pounds per hour (summer) to 130,000
pounds per hour (winter). This system provides steam to the existing loop
that services MCV, the Capital District, and several other State, Federal
and City buildings. (See Figure 6.)
Steam and energy demands coupled with operational and cost considerations
resulted in a waste-management concept using refuse to supply a portion of
the steam demand, A refuse facility with the capability of providing
60,000 'Ibs/hr of steam could be used as a base load steam plant. The ex-
isting MCV power plant would be maintained to supply steam during peak
demand periods, thus conserving fuel and perhaps eliminating the need for
the planned expansion of that facility. In addition, the refuse/steam
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FIGURE 6 DOWNTOWN STEAM LOOP
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plant could be readily expanded to serve future downtown area development.
If future building utilities were designed to use the steam loop, greater
economies in operation of the refuse system could be achieved.
The second feasible market for steam produced from refuse is the Bermuda
Hundred Industrial Complex. The area is composed of a cluster of four
steam-in tensive industries located in the Bermuda Hundred area of Chester-
field County. It has a combined continuous steam demand of 200,000 to
300,000 pounds per hour. The industries have shown a preliminary interest
in refuse steam. Steam of appropriate pressure and quality would be pur-
chased from the system at a price negotiated after comparison with present
energy cost. A conventional water-wall incinerator boiler system has been
proposed to generate the 200,000 to 300,000 pounds per hour of steam re-
quired at the Bermuda Hundred Complex.
ENERGY SYSTEM OPTIONS
Two system options are being considered for implementation. First is the
modular concept which uses preengineered, prefabricated systems which can
be stacked to obtain the desired capacity. Significant cost advantages
appear to be available if this concept is workable for a regional-scale
facility (300 to 500 tons/day). The second system option is the more
conventional water-wall incinerator design approach, using large inciner-
ator/boiler units specifically sized, engineered, and built to specific
design criteria. An evaluation of these concepts is being prepared as
part of a subsequent study. The cost advantage of the modular concept
can best be illustrated by reported net operating costs for a 300 ton/day
facility which approaches $2.00/ton. A similarly sized conventional sys-
tem could be expected to have a net operating cost of greater than $5.00
per ton. Although these costs do not include some specific site and
equipment costs such as land, utility distribution, and feed water treat-
ment, the costs are comparable and justify the need for further investigation.
TRANSPORTATION CONSIDERATIONS
The location of potential regional processing and disposal sites and the
distance that wastes must be hauled for disposal are significant costs
to a regional system. With Downtown Richmond considered as approximately
the center of waste generation in the study area, the Downtown Steam
Loop concept requires almost no adjustment to existing hauling routes. The
Burmuda Hundred area, however, would require hauling waste distances of
20 to 25 miles in addition to a waste transfer station. For transportation
costs alone, the Bermuda Hundred alternative then may cost the region
$^ to $5 per ton more to operate annually.
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PHASE I—CONCLUSIONS
In general, the Phase I study concluded:
1) Steam energy is the most marketable energy commodity in our area.
2) Materials recovery has local market interest and applicability
to the technical alternatives evaluated.
3) The Downtown Steam Loop and the industrial complex are our pri-
mary energy market for implernentation.
4) The Downtown Steam System offers economic advantages because no
extraordinary hauling costs will be required.
5) The Downtown Steam System cannot supply a market for all regional
refuse generated and that the industrial complex alternative must
be developed in a total management system.
6) Recovery of ferrous and non-ferrous metals from incinerator
residue is cornpatable with the alternatives evaluated for imple-
mentation and with the economic goals of the Richmond area.
PHASE I I--PROGRAM
Based on these conclusions, the Task Group recommended authorization of
the energy recovery alternatives. The local governments approved the Phase
II program without any additional funding required. Accordingly, the City
executed a contract with the consultant, Roy F. Weston, and work began on
Phase II in September 1976. This study is expected to establish system
capacity, system cost, revenue structure, energy distribution cost, indirect
cost, institutional arrangements, cost sharing, and the administration and
implementation schedule.
The emphasis of our Phase II effort is more institutional then technical.
While answering some technical questions, the program will deal mainly with
those questions asked most often by local decision-makers. These are ques-
tions generally asked: Who will own and operate the system? How will
costs be allocated? How will we guarantee that our wastes are delivered
to the facility? What are our options for procuring a system? What are
our financial options? and How much will it cost?
To answer these questions, the Phase II program includes the following
tasks:
Market Development
A more specific development of local energy and materials market
including discussion of costs, revenues, and commitments. We anti-
cipate that letters of commitment will be the output of this task
from each market.
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Waste Ownership
With private collectors doing a majority of the refuse collection
in our neighboring counties, it is vital that we know how to assure
that the refuse will be delivered to our regional resource recovery
facility. A review of ordinances and our collection system will
result in changes that may be necessary.
Institutional Arrangements
Who owns and operates our regional facility will be the outcome of
this task.
System Procurement
A variety of procurement methods has become available in recent
years for municipalities looking toward implementing a resource re-
covery system. We will investigate our jurisdictional and regional
flexibility in procuring these systems and, if justified, consider
changes to our procurement procedures.
System Development
Additional technical evaluation will be required to understand the
options available to the region. Also, further evaluation of the
modular and conventional approaches to energy recovery will be done.
Field visits to operating systems will be made to further evaluate
operating concepts before a decision is made.
RFP
A request for proposal will be prepared and sent to qualified bidders
to supply an energy recovery system to serve the Richmond Metropolitan
Area and the energy markets identified.
The Phase II program will be more concerned with those aspects of implemen-
tation that involve decision-makers. For that reason, a subcommittee approach
is now being used. Each major task has a subcommittee made up of task
Group Members with specific interest or background for that study task.
The consultant will work directly with each subcommittee. This will fa-
cilitate the transfer of information and involve the Task Groups a little
more deeply in the decision-making process.
The decision-making process will function continuously throughout the
study program. As outputs are generated, they will be presented to the
Task Group which will evaluate, comment and direct legislative and
administrative thinking toward implementation needs. When these steps
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have been completed, the decision-making process can be finalized,
and a plan of action can be established. Final coordination of
political subdivisions will be required to obtain concurrence. The
consultant will present this information as an executive summary, a
report, which will be used to obtain jurisdictional approval to begin the
Request for Proposal stage, establish the implementing agency/procedures,
and initiate jurisdictional agreements.
As a final effort for this phase of the project, a brief request for pro-
posal will be prepared by the consultant: this will outline the program
and its objectives and invite qualified bidders to respond with their pro-
posal for facilities, services, and costs.
When the request for the proposal is completed, estimated to be in June
1977, it is hoped that most questions relating to implementing a system
will have been resolved. Then it will be possible to begin construction
and thereby provide an essential Weston management solution for the Solid
Waste Management needs of the Richmond Metropolitan Area.
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Department of Public Works
Richmond, Virginia
September 24, 1976
QUESTIONNAIRE
CONSIDERATIONS FOR IMPLEMENTING RESOURCE RECOVERY
I. Materials Supply -
A. Annual Tonnage - 400,000
B. Who controls collection of wastes:
1. City of Richmond
2. County of Henrico
3. County of Chesterfield
4. Private collectors
C. How to assure delivery of wastes -
1. Legislation must be developed and/or contracts prepared.
2. It is likely competitive dump charges would be considered.
D. Wastes have no special characteristics.
II. Facility Funding -
A. Capital Funding Options
1. Revenue bonds
2. In dustrial authority bonds
3. Private capital
B. Yes - We had a legal bonded indebtedness limit.
m.
A. Present Operating and amortization costs -
1. Landfilling - $4.00/ton dumping fee
2. Incineration - none
B. No, since landfill space is being rapidly depleted.
C. Remaining landfill life -
Chesterfield County:
Chester - 5-7 Years
Bon Air 1.25 Years
County of Henrico:
Springfield Road 12 years
Nine Mile Road 1.5 Years
City of Richmond
East Richmond Road - 8 Years
Fells Street - 1.5 Years
Maury Street - 2 Years
D. New landfill sites in Richmond are non-existent and zoning is very restrictive in
the counties.
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IV. Resource Recovery Systems Choices:
A. (1) Feasibility studies indicate our best choices to be steam generation in
two locations with'ferrous recovery from residue.
(2) None existing
B. Refuse derived solid fuel preparation was determined not feasible due to no
existing markets in region.
V. Energy and Materials Markets:
A. Do you have readily - available markets for the following:
1. Steam - yes
2. Refuse - derived fuel - No.
3. Natural gas - Yes
4. Fuel Oils - Yes
5. Electricity - Yes
6. Other - No.
B. Do you have available markets for the following:
1. Light ferrous metals - Yes
2. Heavy ferrous metals - Yes
3. Aluminum - Yes
4. Other non-ferrous metals - Yes
5. Flint glass cullet - No.
6. Color sorted glass cullet - No
7. Color-mixed glass fines - No
8. Glass - aggregate - No
9. Recovered paper fibers - Yes
10. Inert Residue - No.
11. Other - no.
VI. Other Institutional legal concerns:
A. No decision has been made on the type institution to operate the facilities.
The transporting of refuse across governmental boundaries and ownership
must also be resolved.
B. Long term contracts would be contingent on the eventual form of institution.
C. The system must meet state rules and regulations for design and air and
water pollution. A permit must be issued and inspections will be made by State.
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APPENDIX
NSWMA Institute of Waste Technology
The National Solid Wastes Management Association's Institute of Waste
Technology (IWT) was established in June of 1974 to assist government and
industry by offering technical and planning expertise in all aspects of
waste management. Representatives of private waste service firms, resource
recovery companies, landfill operators and engineers, public officials, and
researchers serve on the Institute's major committees:
• Chemical Waste Committee
• Industry Resource Recovery Committee
• National Sanitary Landfill Committee
NSWMA Waste Equipment Manufacturers' Institute
The NSWMA Waste Equipment Manufacturers' Institute (WEMI) formed in 1972,
is comprised of 73 leading U.S. manufacturers of wastes handling equipment.
Five major equipment committees of WEMI are:
Incineration and Thermal Energy Systems Committee
Landfill Equipment Committee
Mobile Equipment Committee
Processing Equipment Committee
Stationary Compaction Equipment Committee
SW-22p
-427-
all.S. GOVERNMENT PRINTING OFFICE. 1977 720-115/9849 1-3
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