Alchemy in the Desert, Diesel Exhaust into H2O 63
Carl Bialik writes "The Wall Street Journal is reporting that 'Using technologies developed for the space program, the U.S. Army is conducting an experiment that could convert the exhaust pipes of military vehicles into water fountains.' The idea is meant to help alleviate the logistical challenges presented by two essential army liquids: water and diesel fuel. A soldier in the desert needs about 20 gallons of water a day, for all purposes; 'Water gets to the front in vulnerable, slow-moving truck convoys that require armed escorts, or it is pumped from local rivers, lakes or ponds and purified by heavy-duty filters.' And maybe, in the future, it will also be extracted from diesel exhaust. The president of a company that developed the test technology tells the WSJ: 'This is one of those things where, when you first hear about it, you think the scientists have gone out of their minds. But once you taste the water, you realize the potential.'"
This has come out before (Score:5, Informative)
Wired has a good article on this:
http://www.wired.com/news/print/0,1294,65035,00.h
Re:What about the nasties in the exhaust? (Score:2, Informative)
However, TFA only talks about piping the exhaust through a cat and 6 proprietary filters - making it comparable to tap water.
Potable water is essentail for life. However, it doesn't mean there aren't nasties in it still. Fore example, the city water I get is primairly ground water (95%). This water has uranium in it. If this water was piped directly into homes/businesses, it would be approaching acceptable limits. So what is done about the uranium? Dilute it down with mountain runoff!
So just because it's comparable to tap doesn't mean it's all roses and baby farts.
Re:Chlorine? (Score:2, Informative)
"From there, the decidedly unappetizing-looking water moves to a series of six "treatment beds," which consist of proprietary carbon filters developed by LexCarb. The first four filters strain out black gunk so that the water becomes amber. The final two filters remove remaining impurities, resulting in water that is as clean, or cleaner, than the tap water of many U.S. cities."
Supposedly, the water is "cleaner than tap water in many U.S. cities" before they add the chlorine solution. The brown color you are talking about seems to exist only mid-way through the series of filters.
As for why they don't use a UV filter. The article later explains that the chlorine is meant to stop bacteria from developing in the water well after the purification process is over. I can understand how UV/RO membrane would kill/catch any bacteria present but I don't think it would stop re-contamination later (honestly, I'm not exactly familiar with how RO membranes work but I'm assuming its a filter that doesn't stick around in the water afterwards).
-GameMaster
Re:Chlorine? (Score:4, Informative)
After the amber stage is reached, it goes through two more filters and then chlorine is added to keep the water from getting funky while waiting to be dispensed.
So chlorine isn't used as a filtering agent, more of a preservative.
Re:Chlorine? (Score:2, Informative)
I used to work for a RO company; essentially the membrane splits salty water into extra salty water ("brine") and clean product water. A simplistic explanation is that the polar water molecules split the salt lattice into ions, which get surrounded by more H20 molecules. This means you get big H20/ion clumps that can't squeeze through the membrane, and a bunch more smaller plain old H20 molecules that do get pushed through the membrane. Typically before the membrane you have some prefilters to get out the bigger chunks like bacteria and stuff. Some modern RO systems can be run off solar panels, which would be ideal in a desert application. See also Wikipedia's articles on reverse osmosis [wikipedia.org] and RO desalinization [wikipedia.org].
The company I worked for actually had a military contract to see if they could get water from air, using lithium bromide. They had a proof of concept thing done, but they were still working out the bugs when I left.
I think that this is one of the few advantages to having a military with huge amounts of cash; they can fund interesting new technologies that need to actually perform in harsh environments. Although maybe instead of killing people, they could do something more interesting and helpful, like explore the depths of the ocean, or the surface of the moon. Just a thought.
Re:What about the nasties in the exhaust? (Score:3, Informative)
Not quite like Catalytic Converters? (Score:3, Informative)
I don't think this will work quite like a catalytic converter, which reduces he emissions into something less nasty. Rather it just extracts chemical H2O from the emissions. I was hoping for news that someone can actually convert the diesel exhaust into something less nasty. That would be a good thing.
Re:Moisture farming? (Score:3, Informative)