using resources

• What is potable water?

  Water that is safe to drink.
• Portable was is not...

  pure because it contains dissolved substances.
• how correct quality water is produced:

  1. Water​ ​is​ ​passed​ ​through​ ​a​ ​mesh​ ​screento​ ​remove​ ​large​ ​bits​ ​e.g​ ​twigs​ ​or​ grit
  2. Chemical are added to make solids and microbes stick together to form sediment and sink
  3. there is then anaerobic digestion of sewage sludge
  4. the water is then sterilised with chlorine to kill any microbes left
• Alternative methods of extracting metals:

  • earths resources of metal ores are limited