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Ch21 a


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Ch21 a

  1. 1. Solid and Hazardous Waste March 23, 2011
  2. 2. Solid Waste and Hazardous Wastes• Solid waste • Industrial solid • Municipal solid waste (MSW)• Hazardous Wastes • Synthetic organic compounds • Toxic heavy metals
  3. 3. More on Solid Waste• Industrial solid wastes • generated by agricultural, mining, and manufacturing activities• Municipal solid waste (MSW) • trash or garbage thrown out by residential or commercial buildings • nearly 5 pounds of MSW per person per
  4. 4. Methods on Disposing Solid Waste• Open dumping • garbage is deposited and often burned on large field or holes in the ground • commonly used in developing countries ; forbidden in most developed countries • uncontrolled release of harmful materials • attraction of rodents and other vermins
  5. 5. Methods on Disposing Solid Waste• Sanitary Landfills • meet specific federal requirement mandated by the Resource Conservation, and Recovery Act for • location • design • operation
  6. 6. More on Sanitary Landfills• Must be constructed with special liners and impermeable soil layers to prevent release of materials to the environment• Procedure must be in place to monitor and control leaks that could contaminate local water supplies and groundwater• Wastes are spread out daily and covered with a layer of either clay or plastic foam
  7. 7. More on Sanitary Landfills• Disadvantages • release greenhouse gases (methane and CO2) as wastes decompose • liquid toxic materials (known as leachate) may leach out of landfill and move download through layers • Air pollution generated from both the
  8. 8. Sustaining Sanitary Landfills• Use clay and plastic liners to prevent leaks• Use pipes that collect leachate• Provide leachate storage tanks and treatment systems• Collect methane gas on site for use as fuel for electricity generation• Use groundwater stations to monitor for
  9. 9. New York, NY and Toronto, Canada• New York: sending most of its trash to landfills in New Jersey,Virginia, and Pennsylvania• Toronto: sending trash generated to landfills in nearby Michigan• Shipping trash to surrounding area is expensive
  10. 10. Incineration of Waste• Advantages • Reduces the volume of solid waste up to 90% • Produces steam to create electrical energy• Disadvantages • Creates GHG emissions of CO2
  11. 11. Reducing Solid Waste Production• Reduce • Reduce consumption of consumer products and energy • Requires less raw material input • Avoids the production of waste from mining processes and air pollutants from energy production
  12. 12. Reducing Solid Waste Production• Reuse • Using reusable materials rather than relying on the production of “one-time use” item • Plastic bottles vs. Refillable water container • over 2 million plastic bottles are
  13. 13. Reducing Solid Waste Production• Recycling • Most wastes that can be recycled are generated during the manufacturing process: pre-consumer or internal waste • Recycle 25-30% of MSW in the U.S. • Materials that can be recycled: • paper
  14. 14. Reducing Solid Waste Production• Two types of recycling: Primary and Secondary• Primary Recycling (a.k.a. closed-loop recycling) • materials are converted into new products of the same type • Example: aluminum can
  15. 15. Reducing Solid Waste Production• Composting • A type of recycling • Using the natural role of decomposing bacteria and fungi to convert biodegradable waste into usable soil amendments
  16. 16. Recycling Advantages and Disadvantages• Advantages • Reduces GHG emission • Reduces need for mining of minerals • Decreases water pollution • Reduces solid waste production and disposal