Handbook Of Pollution Control And Waste Minimization - Chapter 3 doc

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Handbook Of Pollution Control And Waste Minimization - Chapter 3 doc

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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. . 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. 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 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

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  • Contents

  • Chapter 3: The Waste Management Hierarchy

    • 1 Introduction

    • 2 Historical Perspective

    • 3 Technical Approach

    • 4 The Natural Laws

    • 5 Waste Management Choices

    • References

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