8.9: Solid Waste Disposal

Learning Objective:

  • Describe solid waste disposal methods

  • Describe the effects of solid waste disposal methods

Essential Knowledge:

  • Solid waste is any discarded material that is not a liquid or gas. It is generated in domestic industrial, business, and agricultural sectors

  • Solid waste is most often disposed of in landfills. Landfills can contaminate groundwater and release harmful gases

  • Electronic waste, or e-waste is composed of discarded electronic devices including televisions, cell phones,a nd computers

  • A sanitary municipal landfill consists of a bottom luner (plastic or clay), a storm water collection system, a leachate collection system, a cap, and a methane collection system

  • Factors in landfill decomposition include the composition of the trash and conditions needed for microbial decomposition of the waste

  • Solid waste can also be disposed of through incineration, where the waste is burned at high temperatures. This method significantly reduces the volume of solid waste but releases air pollutants.

  • Some items are not accepted in sanitary landfills and may be disposed of illegally, leading to environmental problems. One example is used rubber tires, which, when left in piles, can become breeding grounds for mosquitoes that can spread disease

  • Some countries dispose of their waste by dumping it in the ocean. This practice, along with other sources of plastic, has led to large floating islands of trash in the oceans. Additionally, wildlife can become entrangled in the waste and ingest it.

Solid waste types and sources:

  • MSW (municipal solid waste)

    • Solid waste from cities (households, businesses, schools, etc.

    • Waste “stream” refers to the flow of solid waste to recycling centers, landfills, or trash incineration (burning) facilities

      • Aka - trash, litter, garbage, reduce

        • ~1/3 paper

        • ~2/3 organics (compostable)

  • E-waste:

    • Old computers, TVs, phones, tablets

    • Only ~2% of MSW; considered hazardous waste due to metals like cadmium, lead, mercury, and PBDEs (fireproof chemicals)

  • Can leach endocrine-disrupting chemicals out of landfills if thrown away with regular MSW (should be disposed of at special facilities that recycle parts)