using resources

• potable water- good quality water that is safe to drink.
• potable water is produced by:

  1. passed through a filter bed- to remove solids
  2. chlorine gas is added- to kill any harmful micro-organisms
  3. fluoride added- to prevent tooth decay
  4. ozone and ultraviolet- to sterilize
• to desalinize water:

  1. water is boiled to produce steam, leaving solid salt behind
  2. steam condensed to produce pure water
• sewage treatment includes:

  1. screening and grit removal
  2. sedimentation
  3. anaerobic digestion of sewage sludge
  4. aerobic biological treatment of effluent
• a life cycle assessment (LCA) is a method of assessing the environmental impacts of a product or service.
• to carry out an LCA scientists must look at:

  1. extracting the raw materials
  2. processing
  3. manufacturing
  4. how the product is used
  5. how it is transported
  6. disposal