Minimizing Solid Waste

Transcription

1 Minimizing Solid Waste LESSON 2 Guiding Question: What is the best way to manage our solid waste? Discuss the importance of reducing waste. Describe how composting and recycling help reduce the amount of waste. Reading Strategy As you read, draw a concept map showing the big ideas of waste management. Vocabulary source reduction, biodegradable, composting, recycling, material recovery facility (MRF) Waste can degrade water quality, soil quality, and air quality, thereby degrading human health and the environment. Waste is also a measure of inefficiency, so reducing waste can potentially save industries, municipalities, and consumers both money and resources. And finally, waste is ugly to look at. For these and other reasons, waste management has become a vital pursuit. There are two main strategies for managing solid waste reducing the amount of solid waste, and recovery. Recovery includes both composting and recycling. Recycling is not a concept that humans invented; recall that all materials are recycled in ecosystems. Therefore, recycling is a fundamental characteristic of the way natural systems function. Waste Reduction One of the best ways to manage solid waste is to reduce the amount we generate. Many industrialized nations must deal with the issue of ever-increasing waste. Waste managers are now relying on reduction, reuse, recycling, and composting to deal with their waste. As a result, they are greatly reducing the amount of solid waste that gets disposed of in sanitary landfills or incinerators. When we reduce the amount of waste, we lower the costs of disposal and recycling. We also conserve resources and produce less pollution. Preventing waste generation this way is called source reduction. One way to achieve source reduction is through less consumption. Other strategies for source reduction include less packaging, banning certain plastics, and designing goods that last longer. To reduce waste, you can save items to use again or substitute disposable goods with durable ones. Habits as simple as bringing your own coffee cup to coffee shops or bringing sturdy reusable cloth bags to the grocery store can, over time, have substantial effect. You can also donate unwanted items and shop for used items yourself at yard sales and resale centers. Over 6000 reuse centers exist in the United States, including stores run by organizations that resell donated items. Besides being good for the environment, reusing items is often economically advantageous. Used items can be as functional as new ones, and much cheaper LESSON PLAN PREVIEW Real World Students make a plan to reduce school waste. Inquiry Students research the meaning of plastic recycling numbers RESOURCES Scientific Method Lab, Overpackaging Scientific Method Lab, Observing a Compost Graph It, Municipal Solid Waste Trends in the U.S. Lesson 19.2 Worksheets Lesson 19.2 Assessment Chapter 19 Overview Presentation GUIDING QUESTION FOCUS Show students a picture of a landfill. Have each student brainstorm a list of three ways that the amount of waste sent to landfills could be reduced. Ask students to share their lists with the class. Use students responses to introduce the lesson topic: ways to minimize solid waste. Waste Management 589

2 Figure 7 Less Packaging By choosing fruits and vegetables with less packaging like those sold at farmers markets or farm stands you can reduce the amount of garbage caused by excess packaging. Reduce Packaging Reducing packaging cuts down on waste, but how, when, and how much should we reduce? Packaging can serve very worthwhile purposes, such as preserving freshness, preventing breakage and tampering, and providing information. But, too much packaging is extraneous. Consumers can help reduce packaging waste by choosing goods with minimal packaging. You can also buy foods in bulk, and buy unwrapped fruits and vegetables (Figure 7). Manufacturers can also help by using packaging that is more recyclable. They can also reduce the size or weight of goods and materials. This reduction in size has been successful with aluminum cans, plastic soft drink bottles, and personal computers. Reduce Use of Nonbiodegradable Plastics Each year, Americans discard 100 billion plastic grocery bags. These lightweight bags are a major source of waste and litter. Because they are not biodegradable, they do not decompose or break down naturally. In fact, most plastic material can last for centuries in the environment. Even worse, plastics can choke and entangle wildlife (Figure 8). Several nations have already either taxed or banned the use of plastic bags. When Ireland began taxing plastic bags, most people stopped using them. San Francisco became the first city in the United States to ban nonbiodegradable plastic bags. Figure 8 Effect of Plastics in the Environment Plastic grocery bags, as well as other plastics, are found in coastal areas as well as inland. Plastic six-pack rings and plastic bags often entangle wildlife, sometimes with fatal results. 590 Lesson 2

3 Reduce, Reuse, Recycle 1 Collect one day s worth of dry trash. 2 Sort the trash into items that can be reused, recycled, or discarded because they can t be reused or recycled. Analyze and Conclude 1. Analyze Data Look at the trash you have sorted. Roughly what percentage of the total does each type represent? 2. Predict What do you think happens to the trash you produce? Think of at least three ways trash can affect living things. 3. Evaluate List three ways you can reduce the amount of trash you produce. Design Goods to Last Increasing the lifetime and durability of goods also helps reduce waste. Consumers generally choose goods that will last longer. To maximize sales, however, some companies intentionally design goods that will quickly wear out or become outdated. As a result, we buy new goods to replace them. Examples include computers, technical gadgets, the latest sneaker, the coolest sports gear; and disposable goods such as pens, cameras, and cell phones. Financial Incentives Some states or municipalities use economic incentives to reduce waste. For example, the pay-as-you-throw approach to garbage collection uses a financial incentive to influence consumer behavior. In these programs, municipalities charge residents for home trash pickup according to the amount of trash they put out. The less waste the household generates, the less the resident has to pay. More than 7000 of these programs now exist in the United States. Bottle bills represent another approach that uses financial incentives. Eleven U.S. states have these laws, which allow consumers to return empty bottles and cans to stores or collection facilities and receive a refund generally 5 cents per bottle or can. The first bottle bills were passed in the 1970s to cut down on litter, but they have also served to decrease waste. In states where bottle bills have been enacted, the laws have been both popular and effective (Figure 9). In fact, bottle bills are recognized as among the most successful state legislation of recent decades. States with bottle bills have reported that their beverage container litter has decreased by 69 84% and their total litter has decreased by 30 64%. Figure 9 Success of Bottle Bills Data suggest that bottle bills increase recycling rates and that higher redemption amounts boost recycling rates further. The five states with bottle bills shown in this graph all have higher recycling rates than the United States as a whole. Michigan, the only state with a 10 cent deposit, has the highest recycling rate of all. Percent container redemption rate ANSWERS Quick Lab 1. Answers will vary. 2. Sample answer: I think most of my trash goes to a landfill. Trash can affect living things by taking up space in habitats, contaminating water and air, and harming wildlife that mistake trash for food. 3. Sample answer: I can recycle more items, reuse some materials rather than throwing them away, and avoid products that are heavily packaged. Success of Bottle Bills Michigan Oregon Massachusetts Year Data from Container Recycling Institute, Arlington, VA, California New York United States Waste Management 591

4 Figure 10 Recycling and Composting Since the 1980s, recycling and composting have increased in the United States, reducing the proportion of waste going to landfills or incinerators. Municipal Solid Waste Trends in the U.S. BIG QUESTION How do our choices as consumers and waste producers affect our environment? Application Relate the Big Question to the information about recycling by writing the following statement on the board: Recycling helps reduce waste when consumers choose products that are made of recycled or recyclable materials. Have students use this statement to explain why consumer choices are especially critical to waste reduction through recycling. (Consumer choices are especially critical in reducing waste through recycling because they can impact two separate steps of the process; they can choose to buy recycled goods and they can buy goods that can be recycled after use.) U.S. municipal solid waste (millions of tons) Increases in Recycling and Composting Recovery for composting Recovery for recycling Year Incineration Landfill, other disposal Data from U.S. Environmental Protection Agency, Municipal solid waste generation, recycling, and disposal in the United States: Facts and figures for Waste Recovery The amount of waste can also be reduced by composting and recycling. Recovering our solid waste is the second strategy for waste reduction. When we recover waste, we take material out of the waste stream so that it does not end up in a landfill or incinerator. Prime examples of recovery include composting and recycling. Industrial waste is not regulated in the same way as municipal solid waste. As a result, materials that could have been recovered end up incinerated or in a landfill. According to the EPA, in 2007 we recovered almost one third of our municipal solid waste by recycling or composting it. The data for 2005 are shown in Figure 10. That amount of recovered waste comes to almost 85 million tons. By recycling and composting this waste, we saved energy equal to more than 10 billion gallons of gas. We also prevented the release of more than 190 million metric tons of carbon dioxide (CO 2 ). That s about the same amount of CO 2 that 35 million cars release each year. Composting Composting is the conversion of organic waste into mulch or humus through natural biological processes of decomposition. The compost can then be used to enrich soil. People can place waste in compost piles, underground pits, or specially constructed containers. As wastes are added, heat from microbial action builds up in the interior, and decomposition proceeds. Banana peels, coffee grounds, grass clippings, autumn leaves, and countless other organic items can be converted into rich, high-quality compost through the actions of earthworms, bacteria, soil mites, sow bugs, and other detritivores and decomposers. Home composting is a prime example of how we can live more sustainably by mimicking natural cycles and incorporating them into our daily lives. 592 Lesson 2

5 Figure 11 Composting Straw, grass clippings, leaves, wood chips, and kitchen wastes (eggshells, vegetable and fruit peels, and coffee grinds, for example) are all good things to include in a compost pile. Municipal composting programs 3800 across the United States as of 2010 divert food and yard waste to central composting facilities, where the wastes decompose into mulch that community residents can use for gardens and landscaping. Nearly half of U.S. states now ban yard waste from the municipal trash collection, helping accelerate the drive toward composting. Approximately one fifth of U.S. waste is made up of materials that can easily be composted. Composting reduces landfill waste, enriches soil and helps it resist erosion, encourages soil biodiversity, makes for healthier plants and more pleasing gardens, and reduces the need for chemical fertilizers. Recycling Recycling is the collection of materials that can be broken down and reprocessed to make new items. Recycling reduces the amount of waste that ends up in landfills and incinerators. As Figure 12 shows, the recycling loop contains three basic steps: collection and processing, manufacturing, and purchasing recycled products. All three steps are needed for a successful recycling program. Collection and Processing The first step in a successful recycling program is the collection of recyclable items. Some communities have locations where residents can drop off their recyclables. Other communities have curbside recycling in which trucks pick up recyclables items in front of homes. Curbside recycling is rapidly growing because its convenience increases recycling rates. About 9000 curbside recycling programs across all 50 states now serve nearly half of all American households. 1 Collection and processing of recyclable materials by municipalities and businesses 3 2 Consumer purchase of products made from recycled materials Use of recyclables by industry to manufacture new products Figure 12 Recycling The familiar recycling symbol represents the three components of a sustainable recycling strategy. Waste Management 593

6 Figure 13 Recycled Products To complete the recycling loop, consumers must purchase goods made from recycled materials, such as these bags out of candy wrappers and snack bags, or this fleece made out of recycled water bottles. ANSWERS What Do You Think? Answers will vary but should show students have identified the costs of not recycling and weighed them against the costs of a subsidized recycling program. What Do you think? Should recycling programs be subsidized by governments even if they are run at an economic loss? What types of external costs costs not reflected in market prices do you think would be involved in not recycling, say, aluminum cans? Do you feel these costs justify sponsoring recycling programs even when the programs are not financially self-supporting? Why or why not? Manufacturing The second step of the recycling process begins at a material recovery facility. Material recovery facilities (MRFs) are places where collected recyclables are sorted and prepared for reprocessing. Workers and machines sort items using automated processes. Magnetic pulleys, optical sensors, water currents, and air classifiers separate items by weight and size. MRFs clean the materials and shred them so that industries can use the reprocessed materials to manufacture new goods and materials. Purchasing Recycled Products In order for the recycling loop to function, consumers and businesses must complete the third step in the cycle. Recycled material is also called post-consumer waste. In step 3, industry uses post-consumer waste to create new goods for consumers to buy. Many textbooks are made from some post-consumer paper. Many glass and metal containers are now made from recycled materials. In some city parks, there are benches and pedestrian bridges made from recycled plastics. Glass is sometimes mixed with asphalt to create a new material called glassphalt for paving roads and making paths. Even clothing can be made from recycled plastic bottles as shown in Figure 13. Limits of Recycling Recycling rates vary from one product or material to another. Recycling rates also vary from state to state. Recycling rates among U.S. communities are anywhere from less than 5% to almost 50%. The rapid growth in recycling over the past two decades is due to three factors: economic forces, the need to reduce waste, and the satisfaction of protecting the environment by doing the right thing. Recycling s growth has been propelled in part by economic forces as established businesses see opportunities to save money and as entrepreneurs see opportunities to start new businesses. It has also been driven by the desire of municipalities to reduce waste and by the satisfaction people take in recycling. 594 Lesson 2

7 WA OR NV CA ID UT AZ MT WY CO NM ND SD NE KS OK MN IA MO AR WI IL NY MI PA IN OH WV VA KY NC TN SC MS AL GA ME VT NH MA RI CT NJ DE MD Figure 14 Recycling in the United States U.S. states vary greatly in the rates at which their citizens recycle. TX LA HI AK FL Data are for 2006 (with earlier data for several states), from Simmons, P., et al The state of garbage in America. BioCycle 47: 26. Recycling rates 0-10% 10-20% 20-30% 30-40% 40% or more These two forces have driven recycling s rise even though it has often not been financially profitable. In fact, many of the increasingly popular municipal recycling programs are run at an economic loss. The expense required to collect, sort, and process recycled goods is often more than recyclables are worth on the market. Furthermore, the more people recycle, the more glass, paper, and plastic is available to manufacturers for purchase, driving down prices and profits. Recycling advocates, however, point out that market prices do not take into account external costs in particular, the effects that not recycling has on human health and the environment. For instance, it has been estimated that globally, recycling saves enough energy to power 6 million households per year. And recycling aluminum cans saves 95 percent of the energy required to make the same amount of aluminum from mined virgin bauxite, its source material. As more manufacturers use recycled products and as more technologies and methods are developed to use recycled materials in new ways, markets should continue to expand, and new business opportunities may arise. The steps we have taken in recycling so far are central to this transition, which many analysts view as key to building a sustainable economy. ANSWERS Lesson 2 Assessment 1. Waste degrades the quality of the water, soil, and air, and therefore negatively affects human health and the environment. Reducing the amount of waste produced will reduce the amount of material that ends up in landfills and incinerators. 2. Recycling reduces the amount of waste that needs to be transported to a dump, which costs money and uses energy. Recycling can also reduce the energy needed to produce new materials. For example, recycling aluminum uses less energy than making it from bauxite. 3. Sample answer: I would promote a program in which consumers return their containers to the company to be recycled Explain Why is it so important to reduce the amount of our waste? 2. Apply Concepts How does recycling save energy and money? 3. Suppose you are the director of a company that makes boxes that hold soups and juices. These containers are not easy to recycle because they are made up of layers of paper, polyethylene (plastic), and aluminum foil. These are hard to separate in recycling efforts. How can you improve the company s environmental practices while not cutting into profits? Waste Management 595