Life cycle assessment and recycling

• Life cycle assessment is carried out to assess the environmental impact of products in each of the stages: extracting and processing raw materials, manufacturing and packaging, use and operation during its lifetime, and disposal at the end of its useful life, including transport and distribution at each stage.
• Use of water, resources, energy sources and production of some wastes can be fairly easily quantified in a life cycle assessment.
• Allocating numerical values to pollutant effects is less straightforward and requires value judgements, so life cycle assessment is not a purely objective process.
• Selective or abbreviated life cycle assessments can be devised to evaluate a product but these can be misused, for example, in support of claims for advertising purposes.
• Reduction in use, reuse and recycling of materials by end users reduces the use of limited resources, use of energy sources, waste and environmental impacts.
• Metals, glass, building materials, clay ceramics and most plastics are produced from limited raw materials.
• Obtaining raw materials from the Earth by quarrying and mining causes environmental impacts.
• Some products, such as glass bottles, can be reused.
• Glass bottles can be crushed and melted to make different glass products.
• Other products cannot be reused and so are recycled for a different use.
• Metals can be recycled by melting and recasting or reforming into different products.
• The amount of separation required for recycling depends on the material and the properties required of the final product.
• E.g., some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.