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Waste Management Notes

Waste Management Notes. Miller, Ch. 21, page 560. 1. E-Waste Consists of Discarded Computers & Other Electronic Waste. E-waste contains many valuable metals as well as toxic pollutants. Much of this waste is transferred from the developed world to the developing world, particularly China .

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Waste Management Notes

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  1. Waste Management Notes Miller, Ch. 21, page 560 1

  2. E-Waste Consists of Discarded Computers & Other Electronic Waste. E-waste contains many valuable metals as well as toxic pollutants. Much of this waste is transferred from the developed world to the developing world, particularly China. The U.S. produces almost half of the world's e-waste but only recycles about 10-15% of it. CORE CASE STUDY Figure 21-1 2

  3. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? • Solid waste: any unwanted or discarded material we produce that is not a liquid or gas. • Industrial solid waste: produced by mines, agriculture, & industries that supply people with goods and services. • Municipal solid waste (MSW): often called garbage or trash, which is produced by homes & workplaces. 3

  4. In developed countries, most MSW is buried in landfills or burned in incinerators. In many developing countries, much of it ends up in open dumps, where poor people eke out a living finding items they can sell for reuse or recycling. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? 4

  5. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? • Solid wastes polluting a river in Jakarta, Indonesia (a city of more than 11 million people); the man in the boat is looking for items to salvage or sell. Figure 21-3 5

  6. Hazardous (toxic) waste: threatens human health or the environment because it is poisonous, chemically reactive, corrosive, or flammable. Includes industrial solvents, hospital/medical wastes, car batteries (containing lead & acids), pesticides, dry cell batteries (containing mercury & cadmium), & incinerator ash. Highly radioactive waste produced by nuclear power plants & nuclear weapons facilities: such wastes must be stored safely for 10,000 to 240,000 years depending on which radioactive isotopes are present. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? 6

  7. The two largest classes of hazardous wastes are organic compounds (such as various solvents, pesticides, PCBs, & dioxins) & nondegradable toxic heavy metals (such as lead, mercury, & arsenic). What Harmful Chemicals Are in Your Home? Cleaning Gardening Disinfectants Pesticides Drain, toilet, and window cleaners Weed killers Ant and rodent killers Spot removers Septic tank cleaners Flea powders Paint Products Paints, stains, varnishes, and lacquers Paint thinners, solvents, and strippers Automotive Wood preservatives Gasoline Artist paints and inks Used motor oil General Antifreeze Dry-cell batteries (mercury and cadmium) Battery acid Brake and transmission fluid Glues and cements 7 Fig. 21-2, p. 562

  8. 2 reasons for reducing solid & hazardous wastes: ¾’s of these materials represent unnecessary waste of earth’s resources. We could reduce, reuse, & recycle 90% of our MSW using existing technology. Instead we collect, mix, crush, & bury it in holes all over the planet. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? 8

  9. In producing the products we use & often discard, we create huge amounts of air pollution, greenhouse gases, water pollution, & land degradation. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? • The U.S. has 4.6% of the world’s population but produces about ⅓ of the world’s solid waste and buries more than half of it in landfills. 9

  10. [21-1] What are Solid Waste & Hazardous Waste, & Why Are They Problems? • About 98.5% is industrial solid waste. • Mining (76%) • Agriculture (13%) • Industry (9.5%) • The remaining 1.5% is MSW. (Our country leads the world in trash production per person.) • Paper & cardboard (37%) • Yard waste (12%) • Food waste (11%) • Plastics (11%) • Metals (8%) 10

  11. Consider some of what we throw away in the United States: • Enough tires each year to encircle the planet almost 3 times. • An amount of disposable diapers each year that would reach to the moon and back 7 times. • Enough carpet each year to cover the state of Delaware. • About 2.5 million nonreturnable plastic bottles every hour. • About 274 million plastic shopping bags per day, an average of about 3,200 every second. • Enough office paper each year to build a wall 11 feet high across the country from New York City to San Francisco. • Some 186 billion pieces of junk mail (an average of 660 pieces per American) each year, about 45% of which are thrown into the trash unopened!!! • Around 132,000 personal computers and 425,000 cell phones each day. 11

  12. CASE STUDY • Residents of New York City actually throw away less trash today than they have historically. • Despite mandatory recycling, the city has run out of landfill space—it now must ship its trash to other states, as much as 300 miles away. • As oil prices rise, this practice may become prohibitively expensive.

  13. [21-2] How Should We Deal with Solid Waste? One method to reduce waste and pollution is to implement waste management. This high-waste approach accepts waste production as a result of economic growth. It attempts to reduce environmental harm. It transfers the waste from one part of the environment to another. 13

  14. SCIENCE FOCUS: GARBOLOGY • Garbologists study the composition of landfills in the fashion of archaeologists. They have found that items in landfills can resist decomposition for long periods of time due to compaction.

  15. [21-2] How Should We Deal with Solid Waste? One method is waste reduction. This low-waste approach sees solid waste as a potential resource, which should be reused, recycled, or composted. It discourages waste production in the first place. It encourages waste reduction and prevention. 15

  16. [21-2] How Should We Deal with Solid Waste? Most analysts call for using integrated waste management—a variety of strategies for both waste reduction and waste management. Not done in the U.S. or in most industrialized countries where 54% of the MSW is buried in landfills, 25% is recycled, 14% is incinerated, & only 7% is composted. Scientists & economists have estimated that 75-90% of our solid waste could be eliminated by a combination of strategies from the following flow chart: 16

  17. Integrated waste management:wastes are reducedthrough recycling, reuse, and composting or managedby burying them in landfills or incinerating them. Most countries rely primarily on burial and incineration. Raw materials Processing and manufacturing Products Solid and hazardous wastes generated during the manufacturing process Waste generated by households and businesses Remaining mixed waste Food/yard waste Hazardous waste Plastic Glass Metal Paper To manufacturers for reuse or for recycling Hazardous waste management Compost Incinerator Landfill Fertilizer 17 Fig. 21-5, p. 565

  18. [21-2] How Should We Deal with Solid Waste? Waste reduction is based on the 3 Rs: Reduce: consume less & live a simpler lifestyle. Reuse: rely more on items that can be used repeatedly instead of throwaway items. Recycle: separate & recycle paper, glass, cans, plastics, metal, and buy products made from recycled materials. 18

  19. [21-2] How Should We Deal with Solid Waste? To cut waste production and promote sustainability, we must reduce consumption and redesign our products. These are the seven priorities for doing so. Redesign manufacturing processes and products to use less material and energy. Redesign manufacturing processes to produce less waste and pollution. Develop products that are easily repaired, reused, remanufactured, composted, or recycled. Eliminate or reduce unnecessary packaging. Use fee-per-bag waste collection systems. Establish cradle-to-grave responsibility laws. Restructure urban transportation systems. 19

  20. 20 Fig. 21-7, p. 566

  21. [21-3] Why Is Reusing and Recycling Materials so Important? REUSE – increases the lifespan of a product – helps reduce resource use, waste, and pollution; it also saves money. Developing countries reuse their products; but there is a health hazard for the poor who scavenge in open dumps. They can be exposed to toxins or infectious diseases. 21

  22. CASE STUDY • Refillable containers lessen waste. Parts of Canada and 11 U.S. states require deposit fees on all beverage containers. Some people are now calling for a ban on all beverage containers that cannot be reused. • Reusable cloth shopping bags also reduce waste substantially. Plastic bags can take a very long time to break down and they now litter the landscape of many locales. There are governments all over the globe that have banned the use of plastic bags.

  23. [21-3] Why Is Reusing and Recycling Materials so Important? Recycling collects waste materials, turns them into useful products, and sells the new products; it is one of 2 types: Primary (closed-loop) recycling: materials are turned into new, useful products of the same type. Turning used aluminum cans into new ones. 23

  24. Secondary recycling: materials are converted into different products. Used tires shredded and converted into rubberized road surfacing. Newspapers transformed into cellulose insulation. [21-3] Why Is Reusing and Recycling Materials so Important? 24

  25. [21-3] Why Is Reusing and Recycling Materials so Important? Solid waste recycling can be done in a materials-recovery facility (MRF). The wastes are recycled and/or burned to produce energy; but such plants are expensive to build, operate, & maintain. They also require a steady diet of garbage to make them financially successful, which does not promote reducing our MSW. 25

  26. [21-3] Why Is Reusing and Recycling Materials so Important? • Source separation recycling relies on households & businesses to separate their trash: • Paper products • Glass • Metals • Certain types of plastics • Compostable materials These are collected & sold to other dealers. 26

  27. This produces less air and water pollution. This method has less startup costs and operating costs. It saves more energy and provides more jobs than MRFs. Pay-as-you-throw (PAUT) or fee-per-bag waste collection systems charge for the mixed waste that is picked up, but do not charge for the recycled, separated materials. [21-3] Why Is Reusing and Recycling Materials so Important? 27

  28. [21-3] Why Is Reusing and Recycling Materials so Important? • Composting biodegradable organic waste mimics nature’s recycling of nutrients. • Allows decomposer bacteria to recycle yard trimmings, food scraps, etc. • The resulting organic material can be added to soil to aerate it, supply plant nutrients (organic fertilizer), slow soil erosion, retain water, & improve crop yields. 28

  29. Backyard composter drum in which bacteria convert kitchen waste into rich compost. When the compost is ready, the device can be wheeled out to the garden or flowerbeds. 29 Fig. 21-10, p. 570

  30. 3. Compost Needs: 6 to 12 inches of grass clippings leaves or other plant material shade garden fertilizer or manure soil water air 30

  31. About 55% of the world’s industrial tree harvest is used to make paper. Paper is easy to recycle and uses 64% less energy than making new paper from wood—so less water pollution, less air pollution, & less deforestation occurs. The global recycling rate for wastepaper is about 43%. CASE STUDY 31

  32. CASE STUDY • There are many different types of plastics, and many of them end up distributed throughout our environment, particularly our oceans. • Only about 4% of all plastics in the U.S. are recycled. • Plastic recycling is uncommon because plastics are difficult to isolate in different materials, not much individual plastic resin is recoverable per product, and recycled resin is much more expensive than virgin plastic resin due to fossil fuel costs. • Progress is being made in the development of more degradable bioplastics. 32

  33. Discarded solid waste litters beaches, poses a threat to beach users, and washes into the ocean and threatens marine animals. Fig. 21-11, p. 571

  34. [21-3] Why Is Reusing and Recycling Materials so Important? • Factors that hinder reuse and recycling are: • The cost of a product does not include harmful environmental health costs in its life cycle. • Resource-extracting industries receive government tax breaks and subsidies while recycle and reuse industries do not. • The demand and price for recycled materials fluctuates so there is less interest in committing to this method.

  35. Most of today’s plastics are derived from petrochemicals. However, bioplastics date back to the early 1900s. Environmental problems associated with oil have triggered a renewed interest in bioplastics. One advantage of bioplastics is that they have the potential to be composted. SCIENCE FOCUS 35

  36. TRADE-OFFS Recycling Advantages Disadvantages Reduces air and water pollution Can cost more than burying in areas with ample landfill space Saves energy Reduces mineral demand May lose money for items such as glass and some plastics Reduces greenhouse gas emissions Reduces solid waste production and disposal Reduces profits for landfill and incinerator owners Helps protect biodiversity Can save landfill space Source separation is inconvenient for some people Important part of economy 36 Fig. 21-12, p. 573

  37. Globally, MSW is burned in waste-to-energy incinerators, which produce steam for heating or for producing electricity. The advantages & disadvantages of burning solid waste: Reduces trash volume by 90%. High operating costs. [21-4] What Are the Advantages & Disadvantages of Burning or Burying Solid Waste? 37

  38. Pollutes the air with particulates, CO, toxic metals (Hg), & other toxic materials. They produce large quantities of toxic bottom ash and fly ash, which must be disposed of safely (specially licensed hazardous waste landfills). To be economically feasible, they must be fed huge volumes of trash everyday which discourages reuse, recycling, & waste reduction. Intense citizen opposition. [21-4] What Are the Advantages & Disadvantages of Burning or Burying Solid Waste? 38

  39. Waste-to-energy incinerator with pollution controls that burns mixed solid waste &recovers some of the energy to produce steam used for heating or producing electricity. 39 Figure 21-13

  40. 40 Fig. 21-14, p. 575

  41. [21-4] What Are the Advantages & Disadvantages of Burning or Burying Solid Waste? • Most solid waste is buried in landfills, which will leak toxic liquids into the soil & water. 2 types of landfills: • Open dumps: are fields or holes in the ground where garbage is deposited & sometimes burned &/or covered with dirt. Mostly used in developing countries. 41

  42. Sanitary landfills: solid wastes are spread out in thin layers, compacted, and covered daily with a fresh layer of clay or plastic foam. Modern landfills line the bottom with an impermeable liner, which collects leachate; rainwater is contaminated as it percolates through the solid waste. The leachate is collected, stored in tanks and then sent to a sewage treatment plant. But all landfills will eventually leak contaminants. The clay/plastic covering lessons risk of fire, decreases odor, & reduces accessibility to vermin. [21-4] What Are the Advantages & Disadvantages of Burning or Burying Solid Waste? 42

  43. State-of-the-art sanitary landfill, which is designed to eliminate or minimize environmental problems that plague older landfills. 43 Fig. 21-15, p. 576 Fig. 21-15, p. 576

  44. According to the EPA, all landfills eventually leak, passing both the effects of contamination & cleanup costs on to future generations. 44

  45. Oil Antifreeze Air conditioner coolants Lead acid (car batteries) D. Not Allowed in Landfills (Must go to an automotive or environmental company for recycling) 45

  46. [21-5] How Should We Deal with Hazardous Waste? • Three levels of priority for dealing with hazardous waste using an integrated management approach: produce less, convert to less hazardous substances, and put the rest in long-term safe storage. 46

  47. CASE STUDY More than 70% of the world’s e-waste ends up in China. Over 30,000 workers toil in unsafe conditions and are exposed to toxins. Some computer companies now offer recycling, though only 10–15% of the e-waste in the U.S. is recycled, 80% of which is shipped overseas. 47

  48. Physical, chemical, and biological methods can be used to reduce the toxicity of hazardous wastes or to remove them. Physical Methods: using charcoal or resins to filter out harmful solids & distilling liquid mixtures to separate out harmful chemicals; especially deadly wastes can be encapsulated in glass, cement, or ceramics & then put in secure storage sites. [21-5] How Should We Deal with Hazardous Waste? 48

  49. Chemical Methods: using chemical reactions that can convert hazardous chemicals to less harmful or harmless ones. Examples include: Cyclodextrin – removes solvents & pesticides from contaminated soil & groundwater. Nanomagnets – magnetic nanoparticles coated w/compounds that remove pollutants from water. [21-5] How Should We Deal with Hazardous Waste? 49

  50. [21-5] How Should We Deal with Hazardous Waste? • Biological Methods: scientists & engineers consider this type of treatment to be the wave of the future. Examples include: • Bioremediation: bacteria & enzymes help destroy toxic and hazardous waste or convert them to more benign substances. • A contaminated site is inoculated w/an army of microorganisms that break down specific hazardous chemicals, such as organic solvents, PCBs, pesticides, & oil. • Takes longer to work than most physical & chemical methods, but costs much less. 50

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