Desalination plant moves ahead

[BridgeTroll]

Jorge Aguilar, a member of Food and Water Watch, a Washington, D.C., consumer advocacy organization, said that desalination is very energy intensive and that only about 50 percent of the seawater taken into the plant is made into drinking water.

The rest remains in a brine solution that the plant would pump back into the ocean.

"You said they won't kill any fish, but there are microorganisms that are taken up, and a lot of marine life relies on those microorganisms," Aguilar said.

I cannot believe some would sacrifice microorganisms just so we can have fresh water...

[buckethead]

The part of the solar idea that strikes me is that the energy does not need to be stored. Fresh water (the result of the energy used) is stored rather than electricity. Once stored the water remains until it is used, unlike electricity.

The solar model I linked touses a process closer to distillation rather than high pressure filtering. I'm not sure you would be able to generate the energy needed to do high pressure filtering via solar. Certainly not in a cost effective manner.

One aspect of floating system is that it uses cold water from 600 ft below the surface to cool the water vapor created by the heat from the solar panels. It is pumped as a coolant to allow the vapors to condense and then be collected.

Looks promising to me.

[Jason]

I actually thought distillation was the primary method of desalination.  Never thought of forcing water across membranes.

[Dog Walker]

There are no large scale distillation plants for producing water.  Some of the older Navy ships use a modified distillation process to produce their water, but all are being converted to reverse osmosis.

The biggest desalinization plants in the world are in the desert State like Kuwait and Saudi Arabia, etc.  Lots of energy - no water!  The cost of the membranes has come down considerably in the past few years.  Big yachts make their own water this same way too.

Osmosis through a membrane works by pulling water through a permeable membrane from a less salty to a more salty side.  By increasing the pressure on the salty side of the membrane ( a lot!), single molecules of H2O are forced through the membrane, leaving the salt behind.  Thus REVERSE osmosis.

RO water is actually purer than distilled water since distillation can boil off other volatile chemicals even before the water turns to steam. Every time you drink a Coke or a bottle of Aquafina water you are drinking RO water.

[CS Foltz]

Only down side that I see Dog Walker is the power involved. If they are generating their own power good to go but if you have to feed power not sure if it would be a viable process.

[heights unknown]

Don't forget, we (mankind) haven't always had toilets whether indoor or outdoor.  I'll bet when we first came around, we pooped in the grass, in the sand, etc., and the fecal matter or "do do" just decayed away naturally in the air and sunshine...it will decay away and flies and other insects help in that process.  Take that natural decaying process and add modern technology to it, and some Scientists or "brain" should be able to come up with a better way to get rid of human waste, whether it be urine or fecal matter.

Heights Unknown

[Dog Walker]

Only down side that I see Dog Walker is the power involved. If they are generating their own power good to go but if you have to feed power not sure if it would be a viable process.

It takes a whole bunch of power to run the high pressure pumps to make RO work.  The water that washes past the membranes is also made much saltier by the removal or the pure H2O which is a problem if the RO plant is on a river or bay rather than the open ocean.

[buckethead]

RIALTO, California (Reuters) - Fifty miles east of Los Angeles, a small and inconspicuous facility is using something most of us would rather not think about -- household sewage -- to create a resource we can't live without -- fuel.

EnerTech Environmental, an Atlanta startup, on Thursday unveiled the United States' first commercial biosolids-to-energy facility in California's Inland Empire. "Biosolids" is the nice term for processed sewage sludge.


Read more:


http://www.reuters.com/article/GCA-GreenBusiness/idUSTRE55A7DH20090611

[Dog Walker]

If they are burning the bio-solids for fuel it would add a whole new dimension to air pollution!  LOL!