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are two navy oilers setting in moth balls in Suisun Bay, California
that have been maintained well and should be put back in service. Just
clicking on the icons above will point out places they could be put to
use. One retired crew member of USS Kawishiwi, Lia Burris ET1 (SW) has
expressed her concerns recently on DESALINATION.
She encourages the use on new forming technologies. Our retired Engineering Officer, Lary Harris 1975-1978, has the following to say: The Kawishiwi had triple-effect shell evaporators which used steam heat to heat salt water to about 140 degrees Fahrenheit in the presence of a partial vacuum, causing the water to boil, releasing pure water in the form of steam which was condensed into liquid fresh water. This was basically WW II technology, requiring an enormous amount of energy to make very little fresh water while requiring lots of maintenance and constant operator intervention. The Kawishiwi's relatively small crew meant that we often had some surplus H20 to share with other ships. This should not be misinterpreted as efficient or abundant capacity. The current technology for making fresh water from salt is called "Reverse Osmosis" and is made possible by quantum advances in plastics and fabric technology. In an "RO" water maker, salt water under high pressure (800 PSI or so) is forced through a "semi-permeable" membrane, with holes so small that only water molecules can pass through, while salt molecules stay behind. This technology is in a very mature stage now, and is "scalable", with hand operated units so small (about the size of a portable radio) and cheap that they are found in life rafts where they easily make several quarts of water a day, to giant ones used in Persian Gulf countries where they supply the needs of entire cities. They are energy efficient, highly automated and require little maintenance. This would be the technology to use for disaster relief and etc.  |
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