Ch21 a
- 1. Solid and Hazardous Waste March 23, 2011
- 2. Solid Waste and Hazardous Wastes • Solid waste • Industrial solid • Municipal solid waste (MSW) • Hazardous Wastes • Synthetic organic compounds • Toxic heavy metals
- 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. 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. Methods on Disposing Solid Waste • Sanitary Landfills • meet specific federal requirement mandated by the Resource Conservation, and Recovery Act for • location • design • operation
- 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
- 8. 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
- 9. 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
- 10. 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
- 11. 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
- 12. 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
- 13. 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
- 14. 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
- 15. 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
- 17. 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
- 19. Recycling Advantages and Disadvantages • Advantages • Reduces GHG emission • Reduces need for mining of minerals • Decreases water pollution • Reduces solid waste production and disposal