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Desalination Plant Begins Operation in Tampa
ambisinistral writes "The Tampa Tribune reports that the first commercial desalination plant in the U.S. is set to begin operations today. By March the plant is expected to be operating at full capacity, producing 25 million gallons of fresh water a day (10% of the water currently provided to the area from well fields).
There are ecological concerns about returning highly saline water from the plant back into Tampa Bay. Proponents of desalination claim the natural tide cycle will effectively flush the bay of the saline rich discharge, while opponents of the plant feel the ecology of the bay will be badly damaged. Both sides plan on strict monitoring of the situation."
On Curacao, an island in the Caribbean Sea, we desalinate our drinking water since 1928. We call it the 'World's Best Water' (and probably most expensive as well! my past month's waterbill was approx. US$ 120.-).
But what the brine does with our coral reef? I dunno, but ppl who are interested in finding out might get some answers from the ppl of NACRI, the Netherlands Antilles Coral Reef Initiative.
"We'll reach that bridge when we find it" - Suzy Romer, prime minister Netherlands Antilles '98-'99
I decided, as an afterthought, to run a quick calculation based on my last comment :)
I've been told that the average person required about 2 liters of water (64-70 ounces) daily, as a healthy requirement. That's about 2kg worth.
(More if you're a large guy, and/or do a lot of strenuous activity)
Water has a latent heat of vap. of about 2300 joules per gram. So evaporating 2000 grams of water (Assuming it's already at boiling temp) would require 4.5 million joules.
A very conservative estimate of solary energy would be 90 watts per square foot.
Assuming you would want to distill at least a day's supply of water every day (10 hours), you would need about 1.5 sq. feet of collection area.
A collector the size of a peice of plywood (32 sq. foot), under these operating assumptions, could provide over 40 liters of fresh water daily!
This does not include cooling the vapor back into drinkable liquid. You could use the feedwater for that, which will help preheat the feedwater and improve output.
=Smidge=
Yeah, at 100% efficiency... I think you'd be hard-pressed to reach 10% efficiency. That would still be useful, with a 4' x 8' collector producing 4 liters of fresh water per day...
But then, you'd also need to take into account that there aren't a lot of places in the US where you can get consistently sunny skies, clear for ten hours per day. A run of cloudy weather for a couple of weeks would devastate your system unless you had a sizeable reserve tank.
Further, solar evaporators need a surprising amount of maintenance. The surfaces need to be kept clean or the efficiency drops, and they have to be flushed periodically to keep bacteria from growing in the fresh water outlets.
To sum up -- it's do-able, but not quite as easy as building one and then getting free water forever.
Sounds like it might be time for Santa Barbara to turn on the desalinization plant it built in 1991...
w orks/water_resources/bffaq.html
http://ci.santa-barbara.ca.us/departments/public_
> Why the heck are they dumping it? Why not sell
> the salt?
They aren't producing salt. They are producing water that is somewhat saltier than seawater. To produce salt they would need to remove almost as much water as they would starting with plain seawater, and they would produce far more salt than the local market could consume.
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