Chapt13 Lecture

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  • In this chapter and throughout this book, you will read about many cases in which humans have caused serious environmental problems. You will also read about promising, exciting solutions to many of these problems. Your task as a student of environmental science is to gain an idea of what some of the larger current problems are, what some solutions might be, and how you might use knowledge from a variety of disciplines—from biology and chemistry to economics—to develop tomorrow’s strategies for more sustainable living on our planet.
  • Chapt13 Lecture

    1. 1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 13 Lecture Outline
    2. 2. Learning Outcomes After studying this chapter, you should be able to answer the following questions: <ul><li>• What are the major components of the waste stream? How do we dispose of most of our waste? </li></ul><ul><li>• How does a sanitary landfill operate? Why are we searching for alternatives to landfills? </li></ul><ul><li>• Why is ocean dumping a problem? </li></ul><ul><li>• What are the benefits of recycling? </li></ul><ul><li>• What are the “three Rs” of waste reduction, and which is most important? </li></ul><ul><li>• What are some steps you can take to reduce waste production? </li></ul><ul><li>• How can biomass waste be converted to natural gas? </li></ul><ul><li>• What are toxic and hazardous waste? How do we dispose of them? </li></ul><ul><li>• What is bioremediation? Is it a promising solution in waste management? </li></ul><ul><li>• What is the Superfund, and has it shown progress? </li></ul>13-
    3. 3. We are living in a false economy where the price of goods and services does not include the cost of waste and pollution. –Lynn Landes, founder and director of Zero Waste America 13-
    4. 4. 13.1 Waste <ul><li>We all produce unwanted byproducts and residues in nearly everything we do. </li></ul><ul><li>According to the Environmental Protection Agency (EPA), the United States produces 11 billion tons of solid waste each year. </li></ul><ul><li>Industrial waste—other than mining and mineral production—amounts to some 400 million metric tons per year in the United States. </li></ul><ul><li>Municipal waste—a combination of household and commercial refuse—amounts to about 250 million metric tons per year in the United States. </li></ul>13-
    5. 5. 13-
    6. 6. 13-
    7. 7. The waste stream <ul><li>The waste stream is a term that describes the steady flow of varied wastes that we all produce, from domestic garbage and yard wastes to industrial, commercial, and construction refuse. </li></ul><ul><li>Many of the materials in our waste stream would be valuable resources if they were not mixed with other garbage. </li></ul><ul><li>Unfortunately, our collecting and dumping processes mix and crush everything together, making separation an expensive and sometimes impossible task. </li></ul>13-
    8. 8. 13.2 Waste Disposal Methods <ul><li>Open, unregulated dumps are still the predominant method of waste disposal in most developing countries. </li></ul><ul><li>The giant developing world megacities have enormous garbage problems (fig. 13.4). </li></ul><ul><li>Most developed countries forbid open dumping, at least in metropolitan areas, but illegal dumping is still a problem. </li></ul>13-
    9. 9. Ocean dumping is nearly uncontrollable <ul><li>Every year some 25,000 metric tons (55 million lbs) of packaging, including half a million bottles, cans, and plastic containers, are dumped at sea. </li></ul><ul><li>Environmental groups estimate that 50,000 northern fur seals are entangled in this refuse and drown or starve to death every year in the North Pacific alone. </li></ul>13-
    10. 10. Landfills receive most of our waste <ul><li>Increasingly, cities have turned to sanitary landfills, where solid waste disposal is regulated and controlled. </li></ul><ul><li>To decrease smells and litter and to discourage insect and rodent populations, landfill operators are required to compact the refuse and cover it every day with a layer of dirt. </li></ul>13-
    11. 11. Incineration produces energy but causes pollution <ul><li>Waste incinerators burn municipal waste. </li></ul><ul><li>This technology is also called energy recovery, or waste-to-energy, because the heat derived from incinerated refuse is a useful resource. </li></ul><ul><li>Refuse-derived fuel is what’s left after unburnable or recyclable materials are removed. </li></ul><ul><li>Mass burn is to dump everything smaller than a sofa into a giant furnace. </li></ul>13-
    12. 12. 13-
    13. 13. 13.3 Shrinking the Waste Stream <ul><li>Having less waste to discard is obviously better than struggling with disposal methods, all of which have disadvantages and drawbacks. </li></ul><ul><li>The term recycling has two meanings in common usage. </li></ul><ul><ul><li>Sometimes we say we are recycling when we really are reusing something, such as refillable beverage containers. </li></ul></ul><ul><ul><li>Recycling is the reprocessing of discarded materials into new, useful products. </li></ul></ul>13-
    14. 14. Recycling captures resources from garbage 13-
    15. 15. Composting recycles organic waste 13-
    16. 16. Reducing waste is often the cheapest option 13-
    17. 17. What Can You Do? Reducing Waste <ul><li>1. Buy foods that come with less packaging; shop at farmers’ markets or co-ops, using your own containers. </li></ul><ul><li>2. Take your own washable, refillable beverage container to meetings or convenience stores. </li></ul><ul><li>3. When you have a choice at the grocery store among plastic, glass, or metal containers for the same food, buy the reusable or easier-to recycle glass or metal. </li></ul><ul><li>4. Separate your cans, bottles, papers, and plastics for recycling. </li></ul><ul><li>5. Wash and reuse bottles, aluminum foil, plastic bags, and so on for your personal use. </li></ul><ul><li>6. Compost yard and garden wastes, leaves, and grass clippings. </li></ul><ul><li>7. Help your school develop responsible systems for disposing of </li></ul><ul><li>electronics and other waste. </li></ul><ul><li>8. Write to your senators and representatives, and urge them to vote for container deposits, recycling, and safe incinerators or landfills. </li></ul><ul><li>Source: Data from Minnesota Pollution Control Agency. </li></ul>13-
    18. 18. 13.4 Hazardous and Toxic Wastes <ul><li>The most dangerous aspect of the waste stream is that it often contains highly toxic and hazardous materials that are injurious to both human health and environmental quality. </li></ul>13-
    19. 19. Hazardous waste includes many dangerous substances <ul><li>Legally, a hazardous waste is any discarded material, liquid or solid, that contains substances known to be: </li></ul><ul><ul><li>fatal to humans or laboratory animals in low doses; </li></ul></ul><ul><ul><li>toxic, carcinogenic, mutagenic, or teratogenic to humans or other life-forms; </li></ul></ul><ul><ul><li>ignitable with a flash point less than 60°C; </li></ul></ul><ul><ul><li>corrosive; or </li></ul></ul><ul><ul><li>explosive or highly reactive (undergoes violent chemical reactions either by itself or when mixed with other materials). </li></ul></ul>13-
    20. 20. Federal legislation regulates hazardous waste <ul><li>Two important federal laws regulate hazardous waste management and disposal in the United States. </li></ul><ul><ul><li>The Resource Conservation and Recovery Act (RCRA, pronounced “rickra”) of 1976. </li></ul></ul><ul><ul><li>The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund Act), passed in 1980 and modified in 1984 by the Superfund Amendments and Reauthorization Act (SARA), is aimed at rapid containment, cleanup, or remediation of abandoned toxic waste sites. </li></ul></ul>13-
    21. 21. 13-
    22. 22. Superfund sites are those listed for federal cleanup <ul><li>There may be over 400,000 “Superfund” sites in the U.S. </li></ul><ul><li>Total costs for hazardous waste cleanup in the U.S. are estimated to be between $370 billion and $1.7 trillion. </li></ul>13-
    23. 23. Brownfields present both liability and opportunity <ul><li>In many cities, there are large areas of contaminated properties, known as brownfields, that have been abandoned or are not being used to their potential because of real or suspected pollution. </li></ul><ul><li>Up to one-third of all commercial and industrial sites in the urban core of many big cities fall in this category. </li></ul>13-
    24. 24. Hazardous waste must be processed or stored permanently <ul><li>There are 3 choices regarding the production and handling of hazardous wastes: </li></ul><ul><li>Produce less waste As with other wastes, the safest and least expensive way to avoid hazardous waste problems is to avoid creating the wastes in the first place. </li></ul><ul><li>Convert to less hazardous substances Several processes are available to make hazardous materials less toxic. </li></ul><ul><li>Store permanently: Inevitably, there will be some materials that we can’t destroy, make into something else, or otherwise cause to vanish. </li></ul>13-
    25. 25. A secure landfill for toxic waste 13-
    26. 26. Practice Quiz <ul><li>1. List some items that can be recycled from construction and demolition waste. </li></ul><ul><li>2. What are solid wastes and hazardous wastes? What is the difference between them? </li></ul><ul><li>3. Describe the difference between an open dump, a sanitary landfill, and a modern, secure, hazardous waste disposal site. </li></ul><ul><li>4. Describe some concerns about waste incineration. </li></ul><ul><li>5. List some benefits and drawbacks of recycling wastes. What are the major types of materials recycled from municipal waste, and how are they used? </li></ul><ul><li>6. What is e-waste? How is most of it disposed of, and what are some strategies for improving recycling rates? </li></ul><ul><li>7. What is composting, and how does it fit into solid waste disposal? </li></ul><ul><li>8. What materials are most recycled in the United States? </li></ul><ul><li>9. What are brownfields, and why do cities want to redevelop them? </li></ul><ul><li>10. What are bioremediation and phytoremediation? What are some advantages to these methods? </li></ul>13-

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