Reduce, reuse and recycle

Using fewer products and materials, or keeping them in use for longer, reduces the demand for new raw materials. Three approaches are reduce, reuse and recycle.

Reducing use

Reducing means using less material in the first place. If less is needed, fewer raw materials must be extracted and less energy is needed to make products. It also prevents waste from being created.

Reusing products

Reusing means using a product again rather than throwing it away after one use. For example, some glass bottles can be used again. Each reuse can avoid the need to make a replacement bottle.

Recycling materials

Recycling means processing used material so that it can be made into new products. For example, glass can be crushed and melted to make different glass products.

Some products cannot realistically be reused. Recycling can keep their materials in use instead, although processing still requires energy. Like reducing and reusing, recycling helps cut waste and reduces the need to extract fresh raw materials.

Evaluating resource-reduction methods

Using fewer resources can reduce the demand for limited raw materials and the waste produced when products are discarded. It can also reduce environmental damage caused by extracting and processing materials. However, a method may use energy or create other waste, so its benefits must be weighed against its costs.

The three approaches can be distinguished by what happens to the product or material:

• Reducing use means using fewer products or less material in the first place.
• Reusing means using a product again rather than discarding it after one use.
• Recycling means processing waste material so it can be made into a new product.

Comparing the approaches

Reducing use can avoid the need to extract raw materials, manufacture products and deal with them as waste. Its benefit depends on what is actually avoided: if a replacement is needed, the resources and energy required for that replacement must also be considered.

Reusing products delays disposal and can reduce the number of new products that need to be made. Reuse may also require resources and energy, for example to clean or transport a product. The benefit depends in part on how many times it can be reused and what each reuse requires.

Recycling materials can supply material for new products without relying entirely on newly extracted raw materials. It also diverts some waste from disposal. However, collecting, transporting and processing waste use energy, and not all collected material can necessarily be recycled.

Weighing the evidence

When comparing options, consider the evidence for each one:

• Raw materials: How much demand for new material does it avoid, especially if that material is limited?
• Energy: How much energy is needed, including for any collection, cleaning, transport or processing?
• Waste: How much waste is avoided, and does the method create other waste?
• Environmental damage: Does it reduce damage from extraction and processing, and does it cause other environmental impacts?

A method may perform well on one measure but less well on another. For example, reuse may avoid making a new product but require energy for cleaning. A judgement should weigh the advantages and disadvantages using the information provided, rather than assume that reducing use, reuse or recycling is always the best choice. The result can depend on the material and the circumstances.

Conserving limited resources

Many useful materials are made from finite raw materials: resources that exist in limited amounts and will not be replaced quickly enough for continued use. These materials include metals, glass, building materials, clay ceramics and most plastics.

Manufacturing also uses energy, much of which comes from limited energy resources. Using fewer materials reduces the need to manufacture new products, so it can conserve both raw materials and the energy resources used in production. It also reduces the amount of waste produced.

Extraction and environmental harm

Raw materials are often obtained from the Earth by mining and quarrying. These activities disturb land, while extraction and processing can cause further environmental harm. When demand for new materials falls, less raw material needs to be extracted and processed. This slows the depletion of finite resources and reduces the environmental damage associated with obtaining them.

Recycling metals

Metal products can be used again rather than always obtaining new metal from ores. A product may be melted and recast into a new shape, or it may be reformed into a different product. Recycling therefore reduces the amount of new metal that needs to be obtained from raw materials.

Separation before recycling

Scrap metal may contain a mixture of materials. Before it can be processed into a new product, it may need to be sorted or purified. The amount of separation required depends on which metal is being recycled and what properties the final product needs.

If other materials would prevent the product from having the required properties, more separation is needed. If the product can tolerate some mixed material, less separation may be acceptable.

For example, some scrap steel can be added to iron from a blast furnace. Using the scrap in this way reduces the amount of iron that must be extracted from iron ore.