Compare and contrast linear and cyclical systems of production.

9 Managing Our Waste

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Learning Outcomes

After reading this chapter, you should be able to

• Compare and contrast linear and cyclical systems of production. • Describe municipal solid waste, including practices and policies surrounding its disposal. • Evaluate the various practices for reducing or minimizing municipal solid waste. • Trace the various paths wastewater treatment can take. • Define industrial waste and explain how industrial ecology can help reduce it. • Identify different types of hazardous waste and the different ways of managing it. • Explain the dangers of e-waste. • Summarize different approaches to designing a cyclical economy.

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The previous five chapters of this book have all had titles that started with the word sustain- ing. They focused on both the challenges and needed next steps in sustaining our agricultural resources, freshwater resources, oceans, energy resources, and atmosphere and climate.

This chapter is a little different in that it is primarily focused on managing. As we’ll discuss, however, managing our waste—and more specifically, minimizing or eliminating waste gen- eration in the first place—will go a long way toward helping sustain all of those resources covered in earlier chapters. Our waste problem is not mainly an issue of what we should do with all the waste we generate, although this is an important concern. It is that we are using vast amounts of resources to produce products that we often only use once and then throw away. The greatest concern with waste is the resource depletion and resulting environmental impact, not the trash generated at the end.

Take, for example, something as simple as an aluminum beverage can. Americans use about 100 billion aluminum cans every year, and we only recycle about half of that total. This means that every year we send roughly 50 billion aluminum cans to landfills or waste incinerators. And while dumping or burning this many cans every year creates environ- mental impacts, the far bigger environmental issue has to do with the impacts of producing aluminum cans in the first place.

Aluminum can production starts with baux- ite mining, an energy-intensive process that involves large, open-pit mines in places like Australia, Jamaica, and Brazil. Bauxite ore is then shipped all over the world in large tanker ships to be refined and converted into

a product known as alumina. Alumina refining is also quite energy intensive and produces a residual slurry that is highly toxic. Alumina then undergoes a process known as smelting, whereby it is heated to form aluminum blocks called ingots; the ingots are then heated and converted into aluminum sheets that can be used to make cans. The newly made aluminum cans can then be filled, labeled, and packaged for distribution and sale. These final steps are also energy intensive and produce a variety of other solid wastes.

As can be seen from this example, the environmental impacts of drinking a can of soda or beer and tossing the can away are mostly “upstream” in the process of producing the can, rather than “downstream” in its disposal. It’s for this reason that environmental scientists make use of an approach known as life-cycle analysis (LCA) in examining and comparing the envi- ronmental impact of a product or process from beginning to end, or “from cradle to grave.” An LCA of aluminum can production shows that it takes 20 times more energy to produce an aluminum can from virgin raw material than to make it from recycled aluminum cans. In this way, LCA can reveal where the biggest environmental impact of a product’s use are located.

This chapter will take a closer look at some of the challenges and opportunities associated with managing the waste products that are generated by our economy. In addition to the

Eye Ubiquitous/SuperStock Recycling aluminum cans cuts down on energy use, land disturbance, and other environmental problems associated with making cans from new raw materials, such as bauxite from this mine.

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Section 9.1 What Is Waste?

familiar household waste (like aluminum cans) that we generate each day, we will also con- sider the impacts and appropriate management of wastewater, industrial waste, and hazard- ous waste. We’ll also consider the rapidly growing challenge of electronic waste, or e-waste. The final section of the chapter will consider a variety of approaches that promise to help substantially reduce or even eliminate waste as an environmental problem to begin with. These approaches are based on a fundamental redesign of our economic system and the ways in which we design, produce, market, consume, and dispose of the products we use in our daily lives.

9.1 What Is Waste?

Broadly speaking, waste is unwanted or unusable material discarded by humans. The word human is a key feature of this definition. This is because environmental scientists know that there is no such thing as waste in nature. In natural systems, all “waste” material that is dis- carded, excreted, or expelled from one organism is useful for another organism. At its most basic, in nature waste = food. For example, when winter arrives and the maple and oak trees in the forests of the book authors’ home state of Pennsylvania drop their leaves, those leaves don’t just pile up as waste. Instead, they become food for bacteria, fungi, worms, and other microorganisms that decompose them, producing humus and returning nutrients to the soil. We can see how natural systems are based on a cyclical design in which no real waste is generated.

For most of human history, humans were also part of these cyclical systems. Small population numbers and the organic nature of virtually all human waste at the time meant that any mate- rial discarded by humans could be broken down and utilized by other organisms. This began to change as human numbers grew and as settlements became larger and more concentrated. The volume of human waste began to grow too large for other organisms to break down, and waste started to pile up and pollute nearby land and water. In just the past few decades, with the introduction of plastics and other synthetic materials, the composition of human waste also changed. Today, with close to 8 billion people on the planet and our economic system generating increasingly novel synthetic materials, we are generating solid, liquid, and gaseous wastes at rates that have created a worldwide waste crisis.

Compared with the cyclical design of natu- ral systems, most human systems are highly linear. In the words of economist Kate Raworth, we have developed a “take-make- use-lose” model of economic activity. Con- sider again the example of the aluminum can. We take bauxite ore and fossil fuels from the ground to make aluminum cans. We then use the aluminum can for 5 or 10 minutes while we sip our favorite bever- age, and then, 50% of the time, we lose that can as waste in a garbage bin. This linear, one-way flow of material that eventually

Huguette Roe/iStock/Thinkstock The average American throws away the equivalent of his or her own body weight in trash every month.

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Section 9.2 Municipal Solid Waste

becomes waste is known as the waste stream. Every time we dispose of an aluminum can, we are forced to go back “upstream” to the beginning of the process and extract more bauxite, fossil fuels, and other materials to make even more aluminum cans. This is a fundamentally different approach than what we find in nature, and it is this linear vs. cyclical contrast that lies at the root of our waste management challenge.

In other words, we can view the massive amounts of waste produced by human systems as a sign of a fundamental “design flaw” in the way we do things. We’ve developed a linear, take- make-use-lose economy that is increasingly focused on producing items that are used only once or a handful of times and then thrown away. Every time we do that, there are “upstream” and “downstream” effects. On the “upstream” side we have to keep extracting raw material from the Earth and must consume large quantities of energy to convert that raw material into useful products. On the “downstream” side we have to keep finding new places to dispose of our consumer and individual waste products.

The results of this design flaw are staggering. The average American throws away the equiva- lent of his or her own body weight in trash every month. This is the direct or “downstream” impact of our current economic system. The “upstream” impacts are even worse. The pro- duction of all the products we use and dispose of generates as much as 35–40 times more waste than what we directly throw away, meaning that our consumption patterns generate the equivalent of our own body weight in solid, liquid, and gaseous wastes every day (Mervis, 2012; Bradford, Broude, & Truelove, 2018). This 35-to-1 upstream–downstream ratio is even more pronounced for some products. For example, it’s estimated that the production of a lap- top computer weighing 2 kilograms (4.4 pounds) results in approximately 14,000 kilograms (31,000 pounds) of waste, when considering the full life cycle of its production—including mining, manufacturing, packaging, and distribution (Lepawsky, n.d.). This is a 7,000-to-1 waste-to-product ratio.

Recall the words of the late ecologist Barry Commoner (1971), who observed that “every- thing must go somewhere” and “there is no away” (p. 39). What then should we do with our waste? Over the long term, the best way to deal with the waste crisis is to fix the fundamen- tal design flaw of our economic system and move from a linear to a cyclical economy. Such a move would work to eliminate waste and create economic systems in which, as in nature, waste = food. Some companies and entrepreneurs are already moving in this direction, and you’ll learn more about their efforts later in the chapter. In the meantime, however, we have to manage the 3.2 million metric tons of solid waste generated worldwide every day, as well as the over 90 million metric tons of “upstream” solid, liquid, and gaseous waste generated each day to produce the products we throw away so quickly.

9.2 Municipal Solid Waste

Municipal solid waste (MSW) is what we usually refer to as “trash” or “garbage.” It consists of common household items like food waste, packaging, old clothing, junk mail, paper/plastic plates and cups, and so on. MSW also includes common office and retail waste, but it excludes industrial waste, hazardous waste, and construction waste. This section will first examine the types and rates of MSW generated in the United States and the methods used to deal with and

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Section 9.2 Municipal Solid Waste

manage that waste. This will be followed by a discussion of some of the environmental and health impacts of MSW, as well as current laws and policies that are in place to manage this issue.

Statistics Figure 9.1 shows trends in MSW generation in the United States from 1960 to 2015. While MSW per capita, or per person, has declined slightly in recent years, Americans still gener- ate substantially more MSW per person than residents of other industrialized nations. For example, per capita generation of MSW is 3.7 pounds per day in Germany, 2.9 in the United Kingdom, and 2.8 in Sweden.

Figure 9.1: MSW generation rates, 1960–2015

Municipal solid waste per person has leveled off since around 1990, but total MSW generation continues to increase.

Source: Adapted from “Advancing Sustainable Materials Management: 2015 Fact Sheet,” by US Environmental Protection Agency, 2018 (

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