APES 8.9 Solid Waste Disposal

Definition of Solid Waste

  • Municipal Solid Waste (MSW): Refers to household, commercial, and institutional waste (not specific to environmental studies).

  • Synonyms: Trash, litter, refuse (important for exams).

  • Sources of MSW:

    • Households

    • Businesses

    • Schools

Waste Stream

  • The waste stream encompasses all solid waste produced.

  • Common fates of waste include:

    • Recycling centers

    • Landfills

    • Incineration

  • Composition:

    • Approximately 33% paper (recyclable)

    • Two-thirds organic (opportunity for composting)

E-Waste

  • E-waste: Discarded electronics, e.g., computers and phones.

  • Represents only 2% of MSW but contains hazardous materials (lead, mercury, etc.) that can act as endocrine disruptors.

  • Proper disposal through specialized recycling is essential to prevent leaching.

Sanitary Landfills

  • Sanitary Landfills: Controlled environments for solid waste disposal in developed nations.

    • Different from a dump, which lacks safety measures.

    • Key Features:

      • Clay/Plastic Liner: Protects groundwater by preventing pollutants from leaking out. Residual leakage often occurs.

      • Leachate Collection System: Manages leachate (contaminated water) to reduce pollution.

      • Methane Recovery System: Collects methane produced from anaerobic decomposition. Can be used for heating or electricity.

      • Clay Cap: Applied once landfill is filled to restore vegetation and limit interactions with wildlife.

Decomposition Rates in Landfills

  • Decomposition is minimal in landfills due to low oxygen, moisture, and organic content.

  • Examples of long-lasting materials in landfills:

    • Newspaper can remain legible for 40 years.

    • Fishing line decomposes over 600 years.

Items Not to Include in Landfills

  • Hazardous Waste: Must not be disposed of in landfills (e.g., antifreeze, electronics) due to toxicity.

  • Recyclables: Metals, plastics, and old tires are examples of items that should be recycled.

  • Cardboard and food waste comprise a significant part of landfill content but can be diverted through recycling and composting.

Issues Related to Landfills

  • Groundwater Contamination:

    • Leachate may carry heavy metals and pollutants affecting nearby water sources.

  • Greenhouse Gas Emissions:

    • Landfills release CO2 and methane, contributing to climate change.

  • NIMBY (Not In My Backyard):

    • Communities resist landfill placement due to associated factors (sight, smell, vermin).

  • Social Justice Issues:

    • Landfills are often located in low-income communities or communities of color due to their limited resources to resist.

Waste Incineration and Ocean Dumping

  • Waste can be incinerated to:

    • Reduce waste volume by up to 90%.

    • Generate electricity through combustion.

  • Concerns with Incineration:

    • Releases air pollutants and leaves behind bottom ash containing toxic materials (lead, mercury).

    • Bottom ash requires careful storage in monitored landfills.

  • Ocean Dumping:

    • Illegal dumping occurs where regulations are weak, contributing to pollution and health hazards for marine life (e.g., the Pacific garbage patch).