Desalination With a Grain of Salt

A couple of posts ago I mentioned that I would write about a desalination theory that may or may not give us a clue about an elegant way to convert ocean water into potable water.

First of all, let me tell you from whence this theory came.  An old man from Southern Utah explained this theory to my brother Dave.  So we need to keep in mind that A) for some reason people like to tell my brother weird stuff and B) southern Utah is a mecca for crazy people.  Remember the harmonic convergence?  Those guys were waiting for aliens to pick them up at four corners (one corner is in southern Utah).  My mom had a cousin who shaved and tattooed her head before she went down so the aliens would recognize her as one of their own.  Come to think of it, she could've been one of their own.  Also southern Utah has produced a whole slew of Polygamists... Warren Jeffs for example. (If you want a fun outing for the kids, you can take them to see the polygamists shopping at Walmart in St. George.  It's kind of like going to see a hostile version of the Amish.) There are people down in the desert there who are living in bunkers and stock piling weapons just in case the Feds come after them.  Oddly enough, people from any of those groups, love explaining stuff to my brother Dave.  Dave usually argues with them, but in a respectful way, which I guess is why they single him out.  I just try to avoid them.

Anyway, here's what the old guy (who may or may not be crazy) told my brother.  He said that when he was younger and working as a scientist, he became impressed with the "fact" that water at different levels in the ocean, had varying levels of salt in them.  The top level was the saltiest (which actually makes sense to me when you think about evaporation occurring at that level).  If this is true, than the deeper you go, the saltier it would get.  But no... this guy said that the water actually had layers of salinity that were measurable.   I don't remember the numbers but the idea was like this: the top foot would be saltiest but would be least salty 25 feet down, but then at 26 feet, it got salty again.  So this guy's idea was that if you built a series of tanks and kept drawing the water from the 25' mark, and then putting it in another tank so it could reach it's equilibrium again, you could just keep doing this until the water was desalinated.

I do not know if it's actually true that water at different levels naturally hold different amounts of salt.  But it's an idea to be put out there and kicked around.  With that in mind, keep in mind who came up with the theory.