Australia tried this years ago.
It’s been an expensive boondoggle.
Technology has been improving, and the Israelis have been seeing good success with desalinization. Of course, just because the Israelis are able to figure out how to make it work for them, doesn't mean the Egyptians will.
My big question is, wouldn't it be easier to grab already-fresh water from the Nile?
The Dutch are pretty successful at it...the entire island of Aruba gets all of its water from a desalination plant- the water is amazingly fresh, clean, and pure.
In 2009 there was a report released from Israel on its water system. A consortium built a reverse osmosis plant and it was selling water to the government waterworks for $0.55 per cubic metre.
AFAIK, it’s still running, has paid itself off, and now it’s turning a profit!