Handbook Of Pollution Control And Waste Minimization - Chapter 3 doc

3
The Waste Management Hierarchy
W. David Constant
Louisiana State University and A&M College, Baton Rouge, Louisiana
1 INTRODUCTION
The management of waste can be approached from several venues, including
regulations, history, technical methods, and interpretations of past management
practices and our current methods to manage waste in what is considered the
proper approach today. This chapter will explore the above approaches to waste
management, present the Natural Laws (1) for the reader’s consideration, and then
describe a simple hierarchy for waste management based on these laws. The im-
pact of the “implementation” of natural attenuation in many remediation schemes
of today is also discussed. The objective is to raise awareness of both the
capabilities and limitations that are placed on society in the management of waste.
2 HISTORICAL PERSPECTIVE
While we have recently increased our awareness of environmental problems and
waste management, these issues have been in effect to some degree since society
began to reach beyond simple existence. Humankind for centuries has developed
and exploited available resources in useful and necessary ways, along with
wasteful approaches. However, significant problems arose once communities,
towns and cities developed into urban centers wherein contamination of water
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
supplies from waste and animals caused significant deaths to occur. Further
industrialization and heavy dependence on fossil fuels has in the past century
greatly increased pressure on the environment to cope with the anthropogenic
materials and methods of humankind’s development. The development of regu-
lations in the United States, described below, best illustrates the interactions for
such a heavily industrialized nation.
In earlier history the best examples of industrial pollution are found in
England (2), where factories contaminated nearby rivers and raised awareness
about the limitations of drinking water sources. Air pollution resulted from use of

coal for fuel, but it was only after many years, in the mid-1800s and later in the
1900s, that regulations and cause-and-effect mechanisms led to control of pollu-
tant levels. Most unfortunate was the episode occurring in London during
December 1952 due to stagnant conditions over the city, wherein pollutant
concentrations resulted in death of about 4000 people from particulates and SO
2
buildup. This event was followed by the passage of the Clean Air Act by the
government of England, which laid the basis for pollution control in that country.
In the United States, the historical perspective can be best represented
through actions and activities in the United States and resulting regulations, to tie
two perspectives together. Initial efforts were focused on water pollution by the
River and Harbor Act of 1899, the Public Health Service Act of 1912, and the Oil
Pollution Act of 1924, all being fairly localized in action. Only after World War
II did the U.S. government take significant action to control pollution problems
with the Water Pollution Control Act of 1948 and the following Federal Water
Pollution Control Act (FWPCA) of 1956, which set funds for research and
assisted in state pollution control with construction of wastewater treatment
facilities. In 1965, the Water Quality Act provided national policy for control of
water pollution. Focusing on drinking water, the Safe Drinking Water Act
(SDWA) of 1974 directed the U.S. Environmental Protection Agency (EPA) to
establish drinking water standards, which occurred in 1975. In 1980, Congress
placed controls on underground injection of waste, requiring permits for the
method. Finally, the SDWA amendments of 1986 led to interim and permanent
drinking water standards.
It was not until the 1972 amendments were made to the FWPCA that the
nation implemented major restrictions on effluents to restore and maintain water
bodies in the United States. The Clean Water Act of 1977 added to this focus with
consideration of toxins being 65 substances or classes as a basis to reduce and
control water pollution. This action led to the initial priority pollutants list, which
included benzene, chlorinated compounds, pesticides, metals, etc. In combina-

tion, then, the FWPCA and CWA provided the National Pollution Discharge
Elimination System (NPDES) permit system in place today.
These regulatory activities, while focused on water media and abatement
of problems in rivers and other water bodies, did not directly address the other
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
media in our ecosystem—soil (land) and air. As industry responded to the water
regulations, unengineered disposal of waste on land (unengineered pits) became
an acceptable and legal method for waste management in many industrial streams,
including petroleum wastes, petrochemical wastes and off-spec products, and
solid waste disposal (old garbage dumps). These activities led to numerous acts
to control and mitigate pollution from dumping, etc. Initial efforts involved
control of the transportation of solid food wastes for swine, for control of
trichinosis. Modern regulations began with the Solid Waste Disposal Act (SWDA)
of 1965 and the National Environmental Policy Act of 1969, which required
environmental impact statements. The Resource Recovery Act of 1970 amended
the SWDA about the time that the Environmental Protection Agency was formed.
True regulation for solid waste management did not come into effect until the
Resource Conservation and Recovery Act (RCRA) of 1976, with guidelines for
solid waste management and a legal basis for implementation of treatment,
storage, and disposal regulations. Also, hazardous wastes and solid wastes were
defined by the RCRA. With numerous amendments, the RCRA was followed by
the Comprehensive Environmental Response, Compensation and Liability Act
(CERCLA) in 1980 to deal with abandoned sites and provide the funds and
regulations to perform cleanups. CERCLA, or Superfund, has been through
numerous revisions, and its effectiveness has come under question due to the great
deal of litigation involving cleanup of old sites.
Air quality needs became apparent in the 1950s due to the Donora,
Pennsylvania, accident, and the linkage shown between automobile emissions and
photochemical smog, but it was not until the Clean Air Act of 1963, and
amendments in the 1960s, 1970s, and 1990s that true national programs were

established for pollution control in the air medium. These regulations were
focused on motor vehicle emissions, and on emissions from industrial sources.
Thus, the United States has “chased” waste management and pollution in all
media, and while regulations are now complex, they do provide for control,
management, and abatement of pollution from recognized sources to water, land
and air.
Two points develop from this brief historical–regulatory review. First,
waste is tied directly to population, and population is growing at a rapid rate, so
these growth centers must manage and direct waste properly to avoid release and
contamination problems. Second, while many countries have significant controls
in place as in the United States, many Third World countries and underdeveloped
regions are “behind the curve” in regulatory and technical development to
manage waste. Many are still dealing with “end-of-pipe” technologies while the
United States and others are dealing with remediation, mitigation, and pollution
prevention. Still others lack the fundamentals of basic treatment technologies and
have significant population growth. Thus our history, in the United States and
England, has the potential to continue to repeat itself, unless proper technology
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
is brought to these developing population areas. While the United States and
England had time to deal with waste issues, our continued use and development
of agricultural land has diminished our resources, and places high stress on those
agricultural lands to provide food for the expanding of society. Hopefully, balance
will be achieved on a global scale in time to meet the population demand
with managed resources and sufficient waste management to protect all media
and humankind.
3 TECHNICAL APPROACH
In order to manage waste properly, we must explore the geography of a process
so that appropriate engineering (and the constraints of different areas of geogra-
phy) can be applied to solve a waste management issue or problem. Let us focus
now on a chemical manufacturing process, wherein raw materials are taken to

manufacture products, such as petroleum to petrochemicals for containers. There
are three distinct areas—the process itself, the facility boundary (fence line), and
“nature” outside the fence line. Historical sites such as those covered in Super-
fund regulations also include a boundary and “nature.” Nature is defined here as
everything except humankind or society. In order to properly apply a sound
technical approach to the waste management of such a manufacturing facility,
each of these three areas must be considered from an engineering perspective.
First, in the process itself, classical chemical engineering is applied, including
reactor design, thermodynamics, unit operations, mass transfer, etc., which are
well established methods in the chemical process industry (CPI). The focus here
is on the process, products, and profit. The second area, the boundary of the
facility, is where the bulk of waste management is located, including recycle,
reuse, treatment, source control, etc. Lines of these two areas are blurred today
with optimization of processes, recycle, and substitution of chemicals to minimize
pollution. However, both of these geographic areas are engineered and controlled
in terms of materials handling, processing, and safety, as would be found in any
chemical process. The third geographic area brings us to nature—the area around
the facility or waste site, where the fate and transport of contaminants released
from the first two regions now takes control. In the realm of environmental
chemodynamics (3), the controlling factors are the transport of chemicals in the
environment, governed by the physical-chemical relationship to reaction, trans-
port, etc. Waste management in this region now involves sorption, sediment
oxygen demand, groundwater modeling, biodegradation, partition coefficients,
and other multimedia processes. The shift in understanding in this region is
significant. We no longer have a reactor vessel, a temperature controller, or a
homogeneous catalyst bed. The systems are heterogeneous, are difficult to scale,
and may not provide consistent or reproducible results when management meth-
ods or technologies are applied to a waste problem. In addition to our lack of
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
control over these systems, problems faced are usually dealing with low levels of

contamination, which are difficult to model, predict, or treat. However, as risk
assessment and exposure assessment methods improve in accuracy and realism,
these problems are being tackled with growing frequency. It is important to
recognize in the natural environment that our efforts are usually secondary to
existing natural forces. An excellent basis to approach management of waste, both
in the CPI model and beyond, in nature, is found in the Natural Laws, as
illustrated below. Also, a significant contrast develops when we look at the
Natural Laws, especially if one compares them to the five elements in the federal
approach to management of hazardous wastes, as listed below:
1. Classification of hazardous waste
2. Cradle-to-grave manifest system
3. Federal standards for treatment, storage, and disposal (TSD) facilities
4. Enforcement with permits
5. Authorization of state programs
4 THE NATURAL LAWS
Dealing with waste falls under the Natural Laws (1,4) and it is from these laws
that the waste management hierarchy is formed:
1. I am, therefore I pollute.
2. Complete waste recycling is impossible.
3. Proper disposal entails conversion of offensive substances into environ-
mentally compatible earthenlike materials.
4. Small waste leaks are unavoidable and acceptable.
5. Nature sets the standards for what is compatible and for what are small
leaks.
Briefly, these laws state the rules we must follow to properly manage waste in
the future. Since we exist, we generate waste, and thereby pollute. This is due to
the second law, which makes complete recycling impossible, as in thermodynam-
ics, wherein no real process is completely reversible—some loss occurs. With
some waste therefore being generated, the third law requires that the material be
returned to the environment (nature) in a compatible format—that is, earth-

enlike—in either a solid, liquid, or gaseous state. When returned, small leaks will
occur, as with minor auto emissions, and these are unavoidable and acceptable,
provided we observe nature’s standards as to what is compatible and how small
(or large) the leaks can be. A logical flow of management choices follows from
these laws.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
5 WASTE MANAGEMENT CHOICES
The following list incorporates all options available and is similar to lists
developed by the EPA and others (5). The management list also supports the
relationship presented by Reible (2) in that environmental impact is proportional
to population times per-capita resource usage divided by environmental effi-
ciency. In words, then, the environmental impact is minimized for a given
standard of living when the environmental efficiency is high or improved.
Reible’s relationship supports the third law, to minimize impact via high environ-
mental efficiency, returning material (and energy) in compatible forms. It is
important to note here that much of the waste discussion focuses on material, and
that energy pollution should not be neglected, due to problems found in changing
river temperatures due to discharge, global warming, etc. To answer the old
question, “How clean is clean?,” a material is clean when it is returned in a form,
amount, and concentration which is acceptable to that found in nature. In other
words, a material is “clean” when its concentration does not exceed the natural
limits of that material in the space established by the balances (material) that
assimilate it (6).
Clearly, then, minimization is the first choice and the optimal one from an
environmental standpoint. However, society demands a certain standard of living,
so for those wastes remaining from minimization, destruction becomes the best
alternative. Why destruction, as such a choice would support technologies such
as incineration? Because it is the molecular structure, among other things, that
provides the toxicity of the compound, and if it can be broken down (hopefully
not yielding a more toxic compound), toxicity can be reduced or eliminated in

efficient and correct incineration processes. However, not all wastes causing
toxicity problems can be destroyed, such as heavy metals passing through an
incinerator. Thus, these materials must be properly treated prior to release,
changing their chemical states or bonding for a less toxic or hazardous form.
Finally, one notes that in all processes such as those above and others, some
residuals always remain, and lead to the final option, disposal. Disposal requires
compliance with the Natural Laws—earthenlike materials acceptable to nature’s
standards for assimilation.
Thus, the hierarchy for waste management is simply:
1. Minimization
2. Destruction
3. Treatment
4. Disposal
While technologies may overlap these steps, all are contained within, which
brings us to an important concept: how does natural attenuation fit into the waste
management scheme above? Natural attenuation, or monitored natural attenuation
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
(MNA), is at the front of waste management schemes for remediation of sites,
coming into favor in the 1990s as a method to employ risk assessment with
source, pathway, and receptor models to decrease active remediation techniques
(and associated costs) and increase passive technologies. Clearly, budgets of
governments and industry cannot support active remediation technologies in
order to return contaminated systems to pristine conditions, and this has been
realized through the use of MNA. In reality, MNA is nothing more than our
understanding of the fifth Natural Law, and the standards set by nature. What we
are observing, understanding, and utilizing in MNA, coupled with active reme-
dies, is simply our quantification of nature’s limits as to what it can assimilate.
Our regulations tie in here with acceptable drinking water or use standards, along
with artificial boundaries placed on problems, such as fence lines and our use
needs. In any case, MNA provides treatment or destruction (reduction in toxicity)

within the four choices for waste management.
Overall, choices for waste management within the hierarchy of minimiza-
tion, destruction, treatment, or disposal are best made on a risk-based approach,
such as that expressed by Watts (7). For a site, or a waste management program
at a facility or other problem, the key elements can be broken down into three
categories—sources, pathways, and receptors. In this manner, a risk-based ap-
proach may be taken by clearly identifying the sources and receptors, and then
testing the pathways for effect, which falls under the realm of chemodynamics,
as discussed earlier. We find then that while government and industry are driven
by regulation and enforcement of waste management options, as with significant
active remediation in the 1980s, the trend is turning strongly now to a risk-based
approach, within the Natural Laws, and by understanding the sources, pathways,
and receptors, and the fate and transport of low-level contaminants in the biota.
REFERENCES
1. W. D. Constant and L. J. Thibodeaux, Integrated Waste Management via the Natural
Laws. The Environmentalist, vol. 13, no. 4, pp. 245–253, 1993.
2. D. D. Reible, Fundamentals of Environmental Engineering, pp. 10–12. Boca Raton,
FL: Lewis Publishers, 1999.
3. L. J. Thibodeaux, Chemodynamics: Environmental Movement of Chemicals in Air,
Water and Soil, pp. 1–5. New York: Wiley, 1979.
4. L. J. Thibodeaux, Hazardous Material Management in the Future. Environ. Sci.
Technol., vol. 24, pp. 456–459, 1990.
5. C. A. Wentz, Hazardous Waste Management. New York: McGraw-Hill, 1989.
6. W. D. Constant, L. J. Thibodeaux, and A. R. Machen, Environmental Chemical
Engineering: Part I—Fluxion; Part II—Pathways. Trends Chem. Eng., vol. 2, pp.
525–542, 1994.
7. R. J. Watts. Hazardous Wastes: Sources, Pathways, Receptors, pp. 38–40. New York:
Wiley, 1998.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.