Sure, in theory we could use the LifeStraw
to purify enough water to quench the thirst of thousands of people, and if Aqua Sciences proves successful in its endeavor
to pull water out of thin air, desalinating the seas could prove unnecessary. Nevertheless, Stephen Salter at Edinburgh University in the UK
is working with a research team to perfect the "Edinburgh Duck" and provide useful water for needy individuals. The desalinating critters convert wave energy into pressure changes that aid the collection of pure water (in the form of steam) from seawater; by lowering air pressure, the system can draw steam from water at lower temperatures. The pressure-driven machines operates sans electricity by using the crashing motion of waves to operate its innards in a "piston-like motion," slowly but surely creating salt-free water that's pumped back ashore through the two legs that tether the duck to the seabed. Although current prototypes are only pumping air, finalized units could be 10 meters in diameter and 20 meters long -- a device large enough to supply water for "more than 20,000 people." While we're sure the targeted audience here is arid countries with good access to seawater, those days at the beach would be much more enjoyable
without generous helpings of NaCl finding their way into our mouths.