Waste Generation, Terrestrial Pollution, and Waste Disposal

Waste Generation

Module 51: Waste Generation

  • Humans are unique in generating waste that other organisms can't use.
  • Waste: Outputs not useful or consumed.
  • Municipal Solid Waste (MSW): Refuse collected from households, businesses, and institutions.
  • MSW generation increased from 1960-2008, then began to decrease.
  • Waste stream: Flow of solid waste recycled, incinerated, landfilled, or otherwise disposed.
  • Paper, food, and yard waste comprise over half of MSW by weight.
  • E-waste: Contains toxic metals that can leach from landfills.

Module 52: The Three Rs and Composting

  • Three Rs: Reduce, reuse, recycle.
  • Reduce: Optimal choice; lowers waste by reducing material use early on.
  • Source reduction: Cuts waste by using less material in design and manufacture.
  • Reuse: Using a discarded product/material again (ideally without extra energy).
  • Recycling: Converting MSW into raw materials for new products.
    • Closed-loop recycling: Recycling into the same product.
    • Open-loop recycling: Recycling into a different product.
  • Composting: Organic matter decomposition under controlled conditions.
    • Enhances soil structure and fertility.
    • Suitable materials: vegetable by-products, manure, yard waste, non-recyclable paper.

Module 53: Landfills and Incineration

  • Landfills are primary MSW destination.
  • Leachate: Pollutant-containing liquid from MSW or contaminated soil.
  • Sanitary landfill: Engineered facility to minimize environmental contamination.
  • Tipping fee: Charge for landfill/incinerator disposal.
  • Siting: Landfill location designation.
  • Landfill environmental consequences:
    • Potential leachate contamination.
    • Anaerobic decomposition generates greenhouse gases.
  • Incineration: Burning waste to reduce volume/mass, potentially generating energy.
  • Ash: Non-combustible residue.
    • Bottom ash: From combustion chamber.
    • Fly ash: From chimney/exhaust pipe.
  • Waste-to-energy: Using incineration heat as an energy source.
  • Incineration environmental consequences:
    • Potential air pollutants.
    • Concentrated, toxic ash requiring special disposal.

Module 54: Hazardous Waste

  • Hazardous waste: Harmful to humans, ecosystems, or materials.
  • Requires trained personnel and treatment before disposal.
  • Resource Conservation and Recovery Act (RCRA): "Cradle-to-grave" tracking of hazardous waste.
  • Superfund Act (CERCLA): Funds cleanup of abandoned hazardous waste sites.
  • Brownfields: Contaminated sites needing cleanup for redevelopment.

Module 55: New Ways to Think About Solid Waste

  • Life-cycle analysis: Assesses materials used/released throughout a product's life.
  • Integrated waste management: Holistic approach using various strategies to minimize environmental impact.