Chapter 16 Review

chapter 16Review

Key Terms

Learning Objectives Revisited

• Explain why we generate waste and describe recent waste disposal trends.

  From an ecological and systems perspective, waste is composed of the nonuseful products of a system. Much of the solid waste problem in the United States stems from the attitudes of the “throw-away society” adopted after World War II. While the United States may be a major generator of solid waste, the lifestyle and goods disseminated around the world have made solid waste a global problem.

• Describe the content of the solid waste stream in the United States.

  Solid waste in the United States is composed of primarily paper, food, and yard waste. The total amount and per capita waste generation was steadily increasing in the United States until the last few years, during which there has been a slight decline.

• Describe the three Rs.

  The three Rs—Reduce, Reuse, and Recycle—divert materials from the waste stream. Reduce refers to activities that encourage a reduction in the use and disposal of materials. Reuse refers to using items multiple times whenever possible. Recycling refers to returning an object to a manufacturing plant where it is turned into the same or another object made from the same material. They are listed in order of least environmental impact to greatest environmental impact.

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• Understand the process and benefits of composting.

  Composting is the diversion of organic material such as food and yard waste from the waste stream and allowing it to decompose into organic soil (humus). Composting, source reduction, and reuse generally have lower energy and financial costs than recycling, but all are important ways to minimize solid waste production.

• Describe the goals and function of a solid waste landfill.

  Currently, most solid waste in the United States is buried in landfills. Contemporary landfills entomb the garbage and keep water and air from entering and leachate from escaping. The potential for toxic leachate to contaminate surrounding waterways is one major concern. The other concern is the generation of methane gas. Siting of landfills often raises issues of environmental justice.

• Explain the design and purpose of a solid waste incinerator.

  Incineration is an alternative to landfills. Its main benefit is that it reduces the waste material to roughly one-quarter of its original volume. In addition, waste-to-energy incineration often uses the excess heat produced to generate electricity. However, incineration generates air pollution and ash, which can sometimes contain a high concentration of toxic substances and require disposal in a special ash landfill.

• Define hazardous waste and discuss the issues involved in handling it.

  Hazardous waste is a special category of material that is especially toxic to humans and the environment. It includes industrial by-products and some household items such as batteries and oil-based paints, all requiring special means of disposal.

• Describe regulations and legislation regarding hazardous waste.

  Though a variety of regulations and legislation have been implemented to address issues of hazardous waste, many problems remain. CERCLA, also called the Superfund Act, is probably the most well-known regulation concerning hazardous waste because it provides for the cleanup of hazardous waste sites.

• Explain the purpose of life-cycle analysis.

  Life-cycle analysis tracks material “from cradle to grave.” Using life-cycle analysis and integrated waste management—which draws on all the available treatment methods—we can make optimal decisions regarding our solid waste.

• Describe alternative ways to handle waste and waste generation.

  The best solution is to design products with a strategy for their ultimate reuse or their dismantling and recycling. This approach has become more common in recent years.