Monday, November 20, 2006

Desalination of Water

I would guess that anyone contemplating the problem of a lack of clean drinking water for people around the world has, at some point, mentioned the ocean and said, "But why can't we use that water?" And then, inevitably, someone slightly more informed has said, "Because it's full of salt and it's very expensive to get the salt out." Well, thanks to some clever engineers, there may be a cheaper way to do it now:

Eikei Martinson and Brandon Moore, both Florida Atlantic University engineering students, spent nearly two years turning a Boca Raton inventor's sketch into a desalination machine that uses the vacuum created at the end of a 33-foot column of water to boil it at room temperature. The steam created from the boiling water is threaded into a condenser to create potable water.


The United States Geological Service estimates it costs $1,000 per acre-foot to desalinate seawater. Raviv said the students' machine will do it for one-tenth of that. It's cheaper partly because it can use wastewater from power plants to boil the water in the vacuum.

Power-plant wastewater is not hot enough to boil water under normal circumstances. But the vacuum the machine creates allows water to boil at a lower temperature, producing the steam that becomes drinking water.

I don't pretend to understand fully how it works, but if they can really do it, it could have a huge impact on public health around the world.

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