using resources

• drinking water has to have low levels of salt
• drinking water must have low levels of what

  salt
• drinking water cant have high levels of microbes such as 


  bacteria
• drinking water cant have microbes such as bacteria
• water that is safe to drink is called potable water
• what is water that is safe to drink called

  potable water
• potable water and pure water are not the same
• what is the difference between pure water and potable water

  potable water contains some dissolved substances and pure water does not
• where does rainwater collect

  aquifers , lakes , rivers , reservoirs
• how to make potable water

  take fresh water

  pass through filter beds to remove leaves and suspended particles

  water is sterilised to kill microbes ( with chlorine or UV light )
• sea water is made potable through desalination
• what does desalination do

  reduce the levels of dissolved minerals to a safe level
• one way of carrying out desalination is to use distillation
• one way of carring out desalination is by reverse osmosis
• desalination is very expensive