CHAPTER 21 SOLID, TOXIC, AND HAZARDOUS WASTE

Transcription

1 144 CHAPTER 21 SOLID, TOXIC, AND HAZARDOUS WASTE Chapter Objectives Identify the components of solid waste. Describe how wastes have been and are being disposed of or treated. Identify how we might shrink the waste stream. Investigate hazardous and toxic wastes. Key Terms Environmental racism Hierarchy Incinerate Reformulate Solvent Waste-to-energy Concept Review 21.1 Solid Waste The United States produces 11 billion tons of solid waste per year. o Fifty percent is agricultural waste, which can be recycled into the soil. o Over 30 percent comes from mining and metal processing. o The remaining industrial waste can be recycled or disposed of in landfills, with the exception of hazardous and toxic wastes. Every person in the United States contributes approximately two-thirds of a ton of waste per year, a far greater amount than our European and Asian counterparts. The flow of waste materials we generate to disposal or recycling is referred to as the waste stream Waste Disposal Methods The most common method of disposing of wastes in most developing countries is in open, unregulated dumps. Most developed countries prohibit open dumping. Illegal dumping of waste oil and solvents, in addition to trash, does occur, however. Until recently, many coastal cities in the United States dumped refuse and sewage into the ocean. o This practice is now prohibited by federal legislation. o Dredge spoil is still being disposed of at sea, however.

2 145 Sanitary landfills regulate and control solid waste disposal. o This helps control pollution because the landfills are lined and enclosed, compact wastes, and cover the wastes with dirt. o Drainage systems are monitored to safeguard water supplies. o Methane recovery systems are being developed to capture this greenhouse gas and use it to provide electricity. Suitable places for waste disposal are becoming scarce and cities must export their trash. o Most industrialized nations have agreed not to export their trash to less-developed countries, but many still do some exportation. o The poor and minority populations are also often targeted as sites for waste disposal. Burning wastes using energy recovery or waste-to-energy methods can produce heat or generate electricity as an alternative to landfilling. o If wastes are sorted to separate unburnable or recyclable materials, this refuse-derived fuel has a higher energy content than a mass burn. o Incinerator ash concentrates toxins, which must be carefully disposed of due to health concerns Shrinking the Waste Stream Recycling is the reprocessing of discarded products into new products. o Some materials are returned to the same use, while others are transformed into entirely new products. o Recycling has quadrupled in the United States since o Two problems recycling faces are price fluctuation and contamination. o In addition to reducing pollution, recycling saves money, energy consumption, and raw materials. Composting yard waste creates a soil amendment that is rich in nutrients. Appliances and electronic devices (e-waste) are demanufactured or recycled to recover toxic compounds and valuable metals, mostly in Asia, where labor is cheap and environmental regulations are weak. Salvaging and reusing materials is more efficient than recycling and requires less energy. The least expensive waste disposal option is to reduce the amount of waste produced in the first place Hazardous and Toxic Wastes Hazardous wastes must be isolated from the waste stream due to the environmental threats they pose. Two federal laws regulate hazardous waste management and disposal.

3 146 o The Resource Conservation and Recovery Act (RCRA) requires testing and management from the material s generation to its disposal. o The Comprehensive Environment Response, Compensation, and Liability Act (CERCLA, or Superfund) is aimed at the containment, cleanup, and remediation of abandoned toxic waste sites. Brownfields are abandoned industrial sites with real or suspected pollution problems. Brownfield recycling is encouraged in order to return properties to the tax base, preventing further groundwater contamination. The safest and least expensive way to deal with waste is not to produce it in the first place. Treating wastes to make them less toxic or to isolate them is also a good alternative. o Bioremediation uses bacteria and plants to absorb and purify effluents. o Permanent storage areas where containers can be retrieved and inspected is a technique used for many supertoxic materials. Class Time: This chapter can be paired with chapters 24 and 25 because much of this material involves how we plan to use and discard materials safely. Spend 3 5 days on waste management practices and then additional time on legislation and planning to maintain and improve the quality of life for all people. Approach and Tips Compare the transition of waste disposal methods in developing and developed countries. Contrast these methods with high-income and low-income, white vs. minority areas and other ethical considerations. If time permits, students can debate the issues presented in the What Do You think? article on environmental justice presented on p Have students compare the process of energy generation in a coal-fired or nuclear plant with that in the garbage incinerator shown in figure 21.9.

4 147 Figure 21.9 Garbage Incinerator Remember to incorporate a discussion of legislation, such as CERCLA (or the Superfund), and the importance of such legislation to industry and community cleanup efforts.

5 148 Figure Hazardous Waste Sites You may want to have students view the film Erin Brockovich at home or after class, depending upon your school s policy on R-rated videos. The idea of using plants and bacteria to clean up toxic waste sites has been used in the AP exam in an essay format. You would want to have students obtain more information on this innovative practice described in the Exploring Science Cleaning Up Toxic Waste with Plants article on p Applications Have students monitor the amount of waste they generate in a week. If appropriate, have them measure the volume after 1 week, as well as the weight of their trash. Garbage collection dates and times vary from neighborhood to neighborhood, so have students design the experiment, with parental approval, based on their collection date for the 1-week period. As part of community service programs, students can volunteer to pick up wastes from roadsides or, in urban areas, from vacant lots or beaches and then classify and discuss the sources of the pollutants, brainstorm, and create a campaign to reduce these wastes and the dumping of them on vacant land areas.

6 149 Discuss the cradle-to-grave philosophy of electronics manufacturing and why it is important to recycle and reuse components from electronics and appliances. Link the discussion to environmental regulations in developing countries in contrast to those in developed countries. If you can visit a landfill, have the students do the following research before you go. Landfills and Recycling Centers Research Procedure: Look up information on landfills and recycling centers to find out: 1. What laws regulate landfills? 2. What government agency oversees landfills? 3. How do landfills work? 4. Find 3 things that are forbidden from going into a landfill. 5. Who purchases recycled materials from recycling centers? 6. What types of recycled material have the biggest demand? 7. What is done with the materials that are recycled but not sold? 8. What does the future look like in regard to landfills? 9. What does the future look like in regard to recycling centers? 10. What are some problems you see regarding landfills? 11. What are some problems you see regarding recycling centers? 12. List at least 5 diseases/disorders that have been attributed to older dumps.

7 Common Mistakes and Misconceptions 150 A common misconception is that everything we put into our recycling bins gets recycled. That is far from the truth. In regards to plastics, unless it has a number 1 or 2 on the plastic (look for a recycling triangle with a number inside it) it is difficult to recycle. The demand is just not there yet for many items. Paper and aluminum are often recycled, but most paper becomes pulp for newspapers. The landfills still get tons of items everyday from the recycling companies. Encourage your students to look for and buy recycled items if they want to change this. However, many times recycled items are more expensive than items made from raw materials. This is something we need to change. Suggested Website Make sure you teach students about what happened at Love Canal. A good website for information is at This is one of the big environmental disasters I teach about in class. You might want to assign this for students to read about. Questions 1. The United States produces 11 billion tons of solid waste each year. About half that amount consists of agricultural waste, such as crop residues and animal manure. More than one-third of all solid wastes are mine tailings and other residues produced by mining and metal processing. Create a pie chart of this information. Explain what the remaining area on the chart would include in terms of solid waste production. 2. Create a simple diagram of a sanitary landfill, highlighting the important features used to protect the environment. 3. Explain the health threat posed by incinerator emissions. List three sources of emissions that could be recycled instead. 4. Differentiate between the health effects posed by hazardous and toxic wastes.