Potable water

• What is the difference between potable water and pure water?

  Potable water contains dissolved substances
• Why is drinking water essential for human life?

  It provides necessary hydration and nutrients
• What are the acceptable levels of dissolved salts in drinking water?

  They must be sufficiently low
• What term do scientists use for water that is safe to drink?

  Potable water
• What is the first step in producing potable water from fresh water?

  Use a good source of fresh water
• What is the purpose of filter beds in water treatment?

  To remove leaves and suspended particles
• How is potable water sterilized in the UK?

  Using chlorine
• What is one alternative method of sterilizing water used in some parts of the world?

  Ozone or ultraviolet light
• Why is fresh water scarce in some countries?

  Only salty water may be available
• What is the main characteristic of seawater?

  It has very high levels of dissolved minerals
• What is desalination?

  Reducing dissolved minerals to acceptable levels
• What is one method of desalination mentioned in the material?

  Distillation
• What is another method of desalination mentioned?

  Reverse osmosis
• What is a drawback of both distillation and reverse osmosis?

  They require large amounts of energy
• Why is the energy requirement a concern for desalination processes?

  It makes them very expensive
• What are the steps to produce potable water from fresh water?

  1. Use a good source of fresh water
  2. Pass through filter beds to remove materials
  3. Sterilize the water to kill microbes
• What are the steps to produce potable water from salty water?

  1. Use desalination to reduce dissolved minerals
  2. Methods include:

  • Distillation
  • Reverse osmosis
• Compare potable water and pure water.

  • Potable water:
  • Contains dissolved substances
  • Safe for drinking
  • Pure water:
  • Contains no dissolved substances
  • Not necessarily safe for drinking
• What are the sources of fresh water in the UK?

  • Rainwater
  • Aquifers
  • Lakes
  • Rivers
  • Reservoirs
• What are the implications of using chlorine for sterilization?

  • Effective against microbes
  • Commonly used in the UK
  • Alternatives include ozone and UV light