10.12 - Reuse & Recycling

Why we reduce, reuse and recycle

• Most manufactured goods come from raw materials taken from the Earth, which are in limited supply (finite), such as metal ores.
• Extracting raw materials is damaging and expensive:
  • Uses large amounts of energy to extract and process them, mostly from burning fossil fuels.
  • Damages the environment through quarrying and mining, which scar the landscape, destroy habitats, and produce waste.

Three ways to conserve raw materials

1. Reducing - Using less of a material in the first place, saving raw resources, energy, and environmental damage.
2. Reusing - Using a product again in its current form, requiring far less energy than recycling because it isn't broken down or reprocessed.
3. Recycling - Breaking down a used product into its raw material to make something new.

All three approaches conserve finite resources, save energy, and reduce waste sent to landfill.

The economic case

• Processes that use less energy cost less to run, especially for materials that are expensive to extract.
• Recycling is an industry that creates jobs in collecting, sorting, and reprocessing waste.
• Recycling isn't always worth doing: the cost of collecting and reprocessing must be weighed against the cost of making the material from scratch.

The problem with plastic waste

• Addition polymers are chemically unreactive and cannot be broken down by microbes; they are non-biodegradable.
• Because they don't rot, discarded plastics persist in the environment for centuries.

Three main problems

1. Landfill - Large volumes of plastic are buried because mixed plastics are difficult and expensive to separate. They occupy valuable space indefinitely.
2. Accumulation in oceans - Plastic litter washed into rivers and seas accumulates, harming marine ecosystems and wildlife.
3. Toxic gases from burning - Burning plastics releases useful energy, but it can produce toxic and polluting gases unless carefully controlled.