Chapter 16-Waste Generation and Waste Disposal

CORE CASE STUDY:Paper or Plastic?

  1. Humans generate waste that other organisms cannot use
  2. Humans us inputs and materials to produce goods.
  3. Outputs include anything not useful or consumed.
  4. Waste includes nonuseful products generated within the system.
  5. The Throw-Away Society
  6. Until a society becomes relatively wealthy, it generates little waste.
  7. Industrialization, wealth, and cultural changes cause consumption to be geared more toward convenience (use once & throw away) and “labor-saving” devices.
  8. Planned obsolescence is the design of a product so that it will need to be replaced within a few years, even if it is still operational
  9. Municipal solid waste (MSW) is the refuse collected by municipalities from households, small businesses, and institutions such as schools, prisons, municipal buildings, and hospitals.
  10. 60% residential, 40% commercial & institutional (US)
  11. As population has grown in the US, so has annual MSW.
  12. Other types of waste include agricultural, mining, and industrial.
  13. MSW by the numbers: US = 4.5 lbs/person/day, Japan = 1.2 lbs/person/day, some indigenous people use up to 98% of daily MSW for other purposes
  14. Developing countries have become responsible for a greater portion of global MSW because of population growth & they are producing more goods & left with the waste generated by production.
  15. Content of the Solid Waste Stream
  16. Includes organic fibers, metals, plastics, petroleum products, manufacturing waste and from packaging and transporting goods.
  17. Waste stream is the flow of solid waste that is recycled, incinerated, placed in a solid waste landfill, or disposed of in another way.
  18. Composition of Municipal Solid Waste
  19. Paper is the largest component at 31%
  20. Organic materials, other than paper, make up 26%
  21. Wood, including construction debris, is 7%
  22. Most of the above material could be recycled or composted instead of going to landfills
  23. All plastics make up 12%
  24. The major sources of MSW divided by weight are containers and packaging (31%), food and yard waste (26%), nondurable goods (25%), durable goods (18%)
  25. E-Waste
  26. Consumer electronics are ~2% of the waste stream
  27. Contain heavy metals or toxic metals
  28. Little infrastructure or incentive exists to recover these materials
  29. Most of the e-waste in the US is exported to China where there no laws regarding protection for workers or proper procedures for recovery
  30. The three Rs and composting divert materials from the waste stream
  31. The “Reduce, Reuse, Recycle” (aka the three Rs) campaign became popular in the 1990s
  1. Reduce
  2. Reducing inputs is the optimal way to achieve a reduction in solid waste generation (known as waste minimization or waste prevention).
  3. Source reduction seeks to reduce waste by reducing, in the early stages of design and manufacture, the use of materials-toxic and otherwise-destined to become MSW.
  4. Provides economic benefits to individuals and corporations or institutions.
  5. Source reduction in manufacturing will result from reducing the materials that go into packaging.
  6. Source reduction can also be achieved by material substitution.
  7. Ex. using reusable vs. disposable cups, switching from petroleum-based paints to nontoxic latex paint
  8. Subaru utilizes all triple R strategies in its zero-waste manufacturing plant.
  9. Reuse
  10. Reuse of a soon-to-be-discarded product or material, rather than disposal, allows a material to cycle within a system longer before becoming part of the output.
  11. Ideally, no additional energy or resources are needed for reuse.
  12. Energy may be used to repair an object or prepare it for transport to be used by another person.
  13. Recycle
  14. Recyclingis the process by which materials destined to become MSW are collected and converted into raw materials that are then used to produce new objects.
  15. Closed-loop recycling is the recycling of a product into the same product. Ex. aluminum cans
  16. Open-loop recycling takes one product, and recycles it into another product. Ex. plastic soda bottles into polar fleece jackets
  17. Recycling rates have increased in the US since 1975, today we recycle ~1/3 of our MSW.
  18. Zero-sort recycling programs allow residents to mix all types of recyclables into one container that is sorted by workers at the facility.
  19. Aluminum and copper are always in high demand, but not so for glass, plastic, and paper.
  20. Requires more energy than reducing or reusing, and therefore has more costs associated with it.
  21. Compost
  22. When organic materials decompose anaerobically in landfills, methane gas is produced.
  23. Compost is the organic matter that has decomposed under artificial conditions to produce an organic-rich material that enhances soil structure, cation exchange capacity, and fertility.
  24. Yard wastes, animal manure, vegetable by-products are all suitable for composting, but not meat and dairy products.
  25. To encourage rapid decomposition, it is important to have a C:N ratio of about 30:1 and to layer dry (brown material) with wet (green material).
  26. Frequent turning is necessary to ensure aerobic decomposition takes place maintain moisture.
  27. Many places in the US have large-scale composting facilities associated with their landfills, where compostable materials are separated from noncompostable materials.
  1. Currently, most solid waste is buried in landfills or incinerated
  2. Historically, waste has been deposited in open dumps that polluted the air and water and attracted pests; still common in developing countries
  3. Landfills, holes in the ground created by the removal of soil, sand, or earth for construction purposes, became popular waste disposal sites in the 1930s
  4. Leachate is the water that leaches through the solid waste and removes various chemical compounds with which it comes into contact.
  5. Harmful leachate found its way into aquifers, rivers, streams, drinking water, and near homes
  6. Landfills
  7. In the US, 1/3 of our waste is reused or recycled, over half is discarded, and the rest is converted to energy through incineration
  8. Landfill Basics
  9. Sanitary landfills are engineered ground facilities designed to hold MSW with as little contamination of the surrounding environment as possible
  10. Constructed with a clay (impedes water flow & retains positively charged metal ions) or plastic lining at the bottom
  11. Pipes collect leachate which may be recycled in the landfill or sent to wastewater treatment
  12. A cap of soil and clay covers the landfill when it is at capacity
  13. Rainfall & other water input is minimized because it encourages anaerobic decomposition
  14. Leachate is regularly tested for toxicity
  15. Suitable for sanitary landfills: composite materials, paper, plastic, glass
  16. Not suitable: metals, household cleaners, oil-based paints, motor oil, antifreeze, electronics, appliances, batteries, organic material
  17. The landfill is divided into cells and when one is full it is capped and the MSW is entombed
  18. A series of pipes collects methane that can be burned off or used to generate energy
  19. Closed landfills can be reclaimed, many are turned into parks, playgrounds, or golf courses
  20. Tipping fees are charged to cover the tremendous cost of building new cells
  21. The name comes from each truck being weighed before it is tipped into the landfill
  22. Average is $35/ton in the US
  23. Can be an incentive to produce less waste or encourage illegal dumping
  24. Choosing a Site for a Sanitary Landfill
  25. Located in a soil rich in clay to reduce migration of contaminants
  26. Located away from rivers, streams, drinking water supplies
  27. Sufficiently far from population centers
  28. Regional landfills are becoming more common because they offer the best economic benefit
  29. Siting is the designation of a location for a new landfill
  30. Always controversial, sometimes politically charged
  31. Source of considerable environmental injustice
  32. Places with financial resources and political influence often adopt the NIMBY (not-in-my-backyard) attitude
  33. Some Problems with Landfills
  34. Locating landfills near populations that do not have resources to object is a global problem
  35. EPA estimates all landfills have some leaching, even after being closed
  36. Anaerobic decomposition generates methane and CO2, both greenhouse gases
  37. Little decomposition takes place without the right mixture of air, moisture & organic material (so capped landfills won’t reduce in size)
  38. Incineration
  39. Anything containing C, H, and O is suitable for incineration
  40. Incineration is the process of burning waste materials to reduce their volume and mass and sometimes generate electricity or heat
  41. Can reduce volume by up to 90% and weight by up to 75%
  42. Incineration Basics
  43. Ash is the residual nonorganic material that does not combust during incineration
  44. Bottom ash is the residue collected underneath the furnace
  45. Fly ash is collected beyond the furnace
  46. Fills roughly ¼ of original volume, can be very toxic
  47. If nontoxic, can go into the landfill, be used in road construction or as an ingredient in cement
  48. SO2 and NOx are collected through air filters
  49. Acidic gases are recovered by scrubbers and neutralized
  50. Waste-to-energy is when heat generated by incineration is used rather than released to the atmosphere
  51. Some Problems with Incineration
  52. Tipping fees are higher for incinerators, ~$70/ton
  53. Siting raises NIMBY and environmental justice issues
  54. May release organic pollutants from the incomplete combustion of plastics and metals
  55. Ash is usually more toxic than original MSW
  56. Need lots of MSW to be efficient & profitable, may encourage less recycling
  57. Uniform burn is difficult to the variety of materials in MSW
  58. Hazardous waste requires special means of disposal
  59. Hazardous waste is liquid, solid, gaseous, or sludge waste material that is harmful to humans or ecosystems (only 5% is recycled)
  60. Most is the byproduct of industrial processes and manufacturing of computers, but can also come from small businesses
  61. Even households generate hazardous waste (1.6 million tons/year)
  62. Handling and Treatment of Hazardous Waste
  63. Most municipalities do not have regular hazardous waste collections because it is more difficult and expensive to dispose of
  64. Residents and business owners are encourage to keep hazardous household waste separate from regular waste and keep until a designated collection day (usually once per year)
  65. The waste must be handled by trained staff, sorted into categories, and altered chemically to be less harmful
  66. Legislative Response
  67. Resource Conservation and Recovery Act (RCRA)-1976
  68. Main goal was to protect human health and the natural environment by reducing or eliminating the generation of hazardous waste
  69. The EPA maintains a “cradle-to-grave” tracking list of hazardous wastes and works with businesses and state and local authorities to minimize hazardous waste generation and ensure it is disposed of properly
  70. Modified with the Hazardous and Solid Waste Amendment (HSWA) in 1984 to encourage waste minimization , phase out disposal on land, and increase law enforcement authority to punish violators
  71. Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) aka as the Superfund Act-1980, 1986
  72. Imposes a tax on the chemical and petroleum industries to fund the cleanup of abandoned and nonoperating hazardous waste sites where no responsible party can be established
  73. Also authorizes the federal government to respond directly to the release or threatened release of substances that may pose a threat to human health or the environment
  74. EPA maintains the National Priorities List (NPL) of contaminated sites that are eligible for clean up funds (Love Canal, NY is the best known site)
  75. Brownfields
  76. EPA created the Brownfields Program in 1995 to help state and local governments clean up contaminated industrial and commercial land that did not qualify for the Superfund list
  77. Brownfields are contaminated industrial or commercial sites that may require environmental cleanup before they can be redeveloped or expanded
  78. International Consequences
  79. Some companies or municipalities will pay developing countries to take their hazardous waste (KhianSea is the most famous example)
  80. On the other hand, a Pennsylvania company accepted Hg from a company in India because they have no facilities for recycling mercury
  81. There are newer ways of thinking about solid waste
  82. Life-Cycle Analysis
  83. Life-cycle analysis is an important systems tool that looks at the materials used and released throughout the lifetime of a product—from the procurement of raw materials through their manufacture, use and disposal
  84. Aka “cradle-to-grave” analysis
  85. May not be able to determine absolute environmental impact, but it can be helpful in assessing economic and energy considerations
  86. Alternative Ways to Handle Waste
  87. Integrated Waste Management employs several waste reduction, management, and disposal strategies in order to reduce the environmental impact of MSW
  88. Major emphasis is placed on source reduction
  89. A combination of recycling, composting, landfills, and incineration may also be used
  90. Ultimate goal = less generation of MSW
  91. Manufacturing must change its process to minimize waste generation before, during and after manufacturing and develop plans for disassembling and recycling durable goods when they are no longer useful
  92. Manufacturing can also look to nature for inspiration in a design process called biomimicry.
  93. Biomimicry is the science and art of discovering and using natural principles to solve human problems. An important goal for a more sustainable society is to make its industrial manufacturing processes cleaner and more sustainable by redesigning them to mimic how nature deals with wastes.
  94. To transition to a low-waste society, we need to understand that:
  95. Everything is connected.
  96. There is no place to send wastes “away.”
  97. Polluters and producers should pay for the wastes they produce.
  98. We should mimic nature by reusing/recycling the materials that we use.

WORKING TOWARD SUSTAINABILITY: Recycling E-Waste in Chile

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