Desalination unit, 2011

One of every six people in the world today doesn’t have enough safe water to drink. Within 30 years, thirst will spread to three-quarters of the world’s population.

Humans use lots of technologies to make fresh water from salty, but they are expensive, energy-intensive, with environmental issues.

  • evaporating water and condensing it somewhere else, leaving the salt behind,
  • actively pushing saltwater through a semi-permeable membrane, leaving salt on one side and fresh water on the other.

It is estimated that some 30% of the world’s irrigated areas suffer from salinity problems and remediation is seen to be very costly.

What’s the problem?
New advances in energy-efficient desalination technology could help provide clean water to those who need it most. How does Nature Make Saltwater Drinkable? – we can learn from some of these ideas.

  • Ask – What are some of the ways to remove salt from seawater?
  • Imagine – If you could imitate Nature, what would you do?
  • Plan, Create – What would you need to build your idea? Are the items you need available now?
  • Improve – What would be needed to make one of the existing desalination processes more efficient and cost effective?

That’s engineering

  • water pump – to transport water from source to desalination facility, and for fresh water distribution – pumping capacity necessary to move the volume of water being processed based on distance and change in elevation.
  • surface tension – many desalination units rely on surface tension. Sea water evaporates in a closed container, the salt is left behind. The fresh water condenses, and can be drained off thanks to surface tension.

Engineering ideas

  • evaporation, condensation, semi-permeable, membrane, osmosis

Do It
Challenges for you to work on…

  • Create a desalinization plant – construct a “solar still” which uses heat from the sun to run a distillation process to cause dew to form on something like plastic sheeting.