[gardeners] Water, was desalization
Margaret Lauterbach (gardeners@globalgarden.com)
Thu, 10 Aug 2000 09:50:37 -0600
At 08:38 PM 08/09/2000 -0500, you wrote:
>They do do it for large cities. When we lived in Saudi Arabia all of our water
>came from a large desal plant about 30 kilometers from where we lived. It
>produced about 10 million gallons a day from water from the Red Sea. It didn't
>use reverse osmosis though, that's only practical in small systems IIRC. The
>plant was built by Mitsubishi and utilized flash evaporation, ie superheated
>boilers. The steam was then condensed, cooled and put into the big tanks and
>then to the pipes to where it was needed. The salt and other minerals remained
>behind and were flushed back into the sea by the next load of water brought in
>through standard filters. Since the Red Sea is about 10 percent more
>saline than
>the other oceans and seas it didn't make much difference. Note: There are NO
>fresh water streams running into the Red Sea at all.
>
>Flash evaporation on that scale is expensive unless you own half the oil
>in the
>world. Many home filters run on reverse osmosis.
>
>George, still posting via the archives
On the subject of water, a scientist-friend is going on a tour to Lake
Baikul in Siberia later this month. He says it contains 20 or 25% (I forget
which) of the fresh water on the planet. The more I think about that, the
more astonished I am. Margaret L, who wonders how long the straw would
have to be...