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Just Add, Umm, Water 496

An anonymous reader writes "The US military has devised a way to ensure its troops in battle need never go hungry - with dried food that can be rehydrated using dirty water or urine. Bleh, but lightweight bleh." The original New Scientist story is available too.
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Just Add, Umm, Water

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  • Weird (Score:4, Informative)

    by Real Troll Talk ( 793436 ) on Friday July 23, 2004 @10:33PM (#9786411) Journal
    "Engineer Ed Beaudry was quoted by the New Scientist as saying that the body would not find using urine to rehydrate food toxic in the short term, but in the long term it would cause kidney damage."

    I think I'd rather steal food from natives than eat US Amry-supplied kidney damaging "food".
    • Re:Weird (Score:5, Insightful)

      by Wog ( 58146 ) on Friday July 23, 2004 @11:37PM (#9786810)
      I think the urine thing is over-emphasized by the press. The idea with such packages is that you can scoop up swamp water if you want. Urine could be used in an absolutely dire emergency, and if I was stranded somewhere and the only fluids I have are the last few ounces in my canteen and my urine... heck yeah, *zip.*

      Then again, if the water situation is really that desperate, wouldn't eating hinder your chances of survival, not help them?

      How much damage would there be, anyway? Any more than, say, regularly drinking whiskey?

      But the whole thing brings to mind a guy I know who sold water filters in the early 90's. He'd demonstrate their effectiveness by pouring coffee through them. Not that anyone would *want to*, but they could. Same deal here.
    • Re:Weird (Score:4, Insightful)

      by PierceLabs ( 549351 ) on Friday July 23, 2004 @11:56PM (#9786907)
      Even in the short term I think I would have some issues asking someone to pee on my food so I could eat it.
    • Re:Weird (Score:4, Insightful)

      by EtherAlchemist ( 789180 ) on Saturday July 24, 2004 @12:00AM (#9786917)
      It's right in the quote you used: "...in the long term it would cause kidney damage." If you're in a situation long enough that you're going to have to pee in a food pouch enough times to be considered long term and thus toxic, you're in a lot more trouble because by that time you've run out of any water source other than the kind you can make.

      Given the current situation most deployed soldiers face- roadside bombs, bullets, kidnappings with beheadings, and the other ways they can be stabbed, shot and blown up, how deadly do you think one or two or even three pissings is going to be? The company that made the membranes said not to use urine unless you have to. But to read your post, it's like that is the standing order on these things: Piss in them if you want to eat. And it's not so.

      It's all good in a hypothetical: "I think I'd rather steal food from natives than eat US Amry-supplied kidney damaging "food"." Seriously? You've got the balls to steal food from some guy who's only goal is to kill you, but you can't suck it up as a LAST RESORT to piss in a pouch? Please. If it came down to being that dire of a situation, just eat the food and let it "rehydrate" in your stomach.

      Good luck surviving any kind of situation which might cause you to step outside the norm.

    • Re:Weird (Score:5, Funny)

      by prockcore ( 543967 ) on Saturday July 24, 2004 @12:06AM (#9786939)
      in the long term it would cause kidney damage.

      Who would have thought that your kidneys couldn't handle a feedback loop.
    • Re:Weird (Score:4, Insightful)

      by NanoGator ( 522640 ) on Saturday July 24, 2004 @01:04AM (#9787207) Homepage Journal
      "I think I'd rather steal food from natives than eat US Amry-supplied kidney damaging "food"

      I'd rather eat whatever isn't lilikely to be poisoned.
  • by Anonymous Coward on Friday July 23, 2004 @10:33PM (#9786414)
    Fortunately, I've never been that hungry. I wonder if the phrase "I could eat my own urinated food" will catch on.
  • ... Troops in battle are going to stop, drop their weapons, and pee on their food for a quick dinner?
  • by Relifram ( 607656 ) on Friday July 23, 2004 @10:34PM (#9786418)
    Wow, just what we needed another way to make MREs more unpalatable!
    • by TheLoneDanger ( 611268 ) on Friday July 23, 2004 @10:37PM (#9786443)
      I would suggest that urine would probably help the taste of MREs quite a bit...
    • So are they going to call them MRPs (Meals Ready to Pee on)?
    • MREs and dirty water (Score:5, Interesting)

      by Infonaut ( 96956 ) <infonaut@gmail.com> on Friday July 23, 2004 @10:59PM (#9786613) Homepage Journal
      MREs are certainly not haute cousine. But I ate a lot of MREs back in the day, and they taste pretty damned good, particularly when you actually *need* energy. Most of the time when Americans eat, it's out of habit, not because we truly need the energy. But when you've been running around doing Uncle Sam's work in the jungle, desert, frozen tundra, or wherever, an MRE hits the spot.

      MREs have gotten steadily better over the years. The first meals were pretty bad. I remember dehydrated chicken & ham loaf (I'm not kidding) with horror. But by the early 1990s they were really good, and they've continued to improve over the years.

      Just ask anyone who had to endure C-rations. They'll tell you about truly crappy combat rations.

      As for the US Army's attempt to come up with a way to use dirty water or urine, the primary goal is to allow soldiers to use dirty water. Don't get too wrapped up in weird urine scenarios. Believe it or not, much of the world drinks water that's hazardous to the health of Americans. Delivery of potable water is a major constraint on the American way of war. We put immense logistical effort into making sure our soldiers get bottled water. This contributes to our outrageously bad tooth to tail ratio, and it makes the military more beholden on civilian contractors to provide logistics support.

      Americans have shown time and time again that we prefer to win wars with logistics, and our enemies know this. Any flexibility, however small, that allows us to reduce our logistics dependency is good in my opinion.

      • by Rosco P. Coltrane ( 209368 ) on Friday July 23, 2004 @11:07PM (#9786651)
        MREs are certainly not haute cousine.

        *US* MREs are not haute cuisine. French MRE are actually incredibly tasty: they come packaged with a single-use heater kit that you assemble under the can and light up, it cooks in about 5 minutes and once it's done, it really is yummy.

        There's a good reason why US military personels were dying to trade all kinds of hardware for rations with the (few) French soldiers in Iraq during Gulf War I.
        • by Infonaut ( 96956 ) <infonaut@gmail.com> on Friday July 23, 2004 @11:17PM (#9786709) Homepage Journal
          French MRE are actually incredibly tasty

          Does anyone else but the US call their combat rations MREs? But I digress. The taste of rations is definitely a matter of opinion. I traded for a few French rations and found them too rich for my taste. BTW, the French and Belgians were anxious to trade for MREs. It seems variety is the real scourge of combat rations. Eat enough of them and you'll crave anything else that provides variety.

          The fact that you have to actually use flame to heat the Franch rations (don't know if this is still true) is a serious mitigating factor in real tactical situations. It means that you wind up eating the damned thing cold. MREs are lighter and can be stripped down more easily, heated in your cargo pocket while you're on the move, and are more practical in general for grunts.

          But then I've never been a huge fan of French food anyway, so take my comparison for what it's worth. If only I could have met some Italians and traded with them. Anyone know how their combat rations taste?

        • by afidel ( 530433 ) on Friday July 23, 2004 @11:53PM (#9786892)
          MRE's are SO much better than C or worse yet K rations that it's not even funny. Hell MRE's are better than a lot of the civilian dehydrated foods I eat while mountaineering (they have a lot less packaging so more food per ounce). If I had to I would piss in a canteen and use my Pur Scout on it to hydrate food, hell I HAVE done just that =)
      • Just ask anyone who had to endure C-rations.

        Way back when they used to include cheap cigarettes with the C-Rats. I guess that was to help you forget about the awful taste of the food.

        If you go even further back, the US Army fed troops beef that was rotten when they bought it. Some troops dies, but Hormel made tons of money off of it.

        LK
    • There was already a reason they are called Meals Refused by Ethiopians...
  • Horrible. (Score:5, Funny)

    by Anonymous Coward on Friday July 23, 2004 @10:34PM (#9786422)
    I suppose you really could say the food was piss poor.
  • Water (Score:3, Interesting)

    by mabu ( 178417 ) * on Friday July 23, 2004 @10:35PM (#9786425)
    I wonder how many millions of dollars were spent on this mostly useless technology? Creating food with dirty water or urine is irrelevent. A soldier can last much longer without food than he can without water. Most people will die within five days if they don't get water. If you don't have access to clean water, you're in much worse shape. Lose 12% of your water and you're dead.
    • Re:Water (Score:5, Insightful)

      by Daniel Boisvert ( 143499 ) on Friday July 23, 2004 @10:38PM (#9786451)
      Yes, and by using the clean water you have for drinking instead of for rehydrating field rations, it lasts that much longer, and therefore, you do too.
      • Sorry, but I don't think there's anything in the current MREs that require hydrating. We have water-activated heaters which use a little (maybe 2 oz) of water, but that's it. Modern MREs aren't really that bad, speaking as someone who has lived on them recently. They get old, but most anything does after a while.
      • Yes, and by using the clean water you have for drinking instead of for rehydrating field rations, it lasts that much longer, and therefore, you do too.

        Would you mind explaining to me, Private Genius, how there's a net difference in water intake between those two scenarios? If you pour a cup of water to rehydrate your meal, you're also drinking it.

        I agree with other posters- this invention is the stupidest thing I've ever heard of and a colossal waste of money.

        • by Daniel Boisvert ( 143499 ) on Friday July 23, 2004 @10:54PM (#9786577)
          Would you mind explaining to me, Private Genius, how there's a net difference in water intake between those two scenarios?

          Not at all. :)

          This allows you to reclaim water that otherwise you would have disposed of. So, if you have 2 canteens' worth of potable water and a puddle, you can drink those canteens, and then reclaim however much you need to rehydrate your meal from the puddle. This gets you 2 canteens plus part of a puddle's worth of hydration. If you don't have this, you only get 2 canteens' worth.

          Alternatively you can reuse those two canteens' worth by using your urine to rehydrate your food, getting double-use out of at least some of that water.
          • because the urea isn't filtered out, they will be thirstier, so more dehydrated. Sort of like drinking sea water.

            Plus, you're going to end up with everyone wanting to wash their hands and brush their teeth SO much more (basic psychology).

            Add the need for more careful hygeine (really wash those plates so there's no cross-contamination) and you end up needing MORE water, not less.

      • water is water... you rehydrate your body one way or another, whether it's added to the food and consumed or consumed by itself. You still need water.
      • Re:Water (Score:3, Insightful)

        by Chris Burke ( 6130 )
        Realize that the water in the rehydrated food will rehydrate you, assuming you then eat the food. Granted, you recycle and thus conserve water by drinking your own piss, but it's not like water used to rehydrate is wasted. If recycling waste water is really the goal, I'd think good portable filters would be a better idea.
      • Re:Water (Score:3, Insightful)

        Not only that, but you reduce the amount of weight you're carrying in rations, which could then be replaced with additional water equal to the lost food weight.
    • Re:Water (Score:5, Interesting)

      by JustDisGuy ( 469587 ) on Friday July 23, 2004 @10:40PM (#9786468)
      It isn't useless technology - an army marches on its belly. And RTFA - they don't actually piss IN their food, they piss ON the PACKAGE the food is in, and a membrane similar to that in a reverse osmosis unit extracts the water from the liquid used to re-hydrate.

      What they ought to do NOW is put the technology in the public domain, and donate a couple of million pouches to the Red Cross. I wonder how reusable the membranes are, and whether they could be used to create clean water once the ration was consumed?
      • You're going to trust a membrane under field conditions? I don't think so. What if someone has a kidney infection?
    • Re:Water (Score:5, Informative)

      by Effugas ( 2378 ) on Friday July 23, 2004 @10:43PM (#9786495) Homepage
      Here, lets talk in some geek terms.

      You know how the more fuel a rocket has, the more fuel it needs, due to the additional weight of that fuel? Understand how most of the fuel is ultimately spent in complete waste, as it's just carrying itself?

      Kind of the same with water. Water is HEAVY -- seven pounds a gallon. We blow quite a bit of it just dragging it around -- and don't worry, it provides all of no calories; it's useful as a catalyst and a cooler, but not as a fuel. Almost all the water we consume is just excreted back out, pretty clean too (urine is one of the purer substances to leave the body). It's be pretty useful to be able to fully filter the stuff and reintroduce it to our food. Perfectly efficient, no, but would you rather lug around 50 pounds of water?

      --Dan
      • You urinate >95% of the water you intake.

        So yes, that is close to perfect. This technology is neither useless nor stupid.
      • Re:Water (Score:4, Informative)

        by Dausha ( 546002 ) on Friday July 23, 2004 @11:02PM (#9786631) Homepage
        Except, water is 8 pounds per gallon. Unless you're talking about the new lower calorie version.

        And, especially when you're a grunt in combat situations, most of your water waste is via sweat, not urine.

        Eventually, all the water we consume we excrete. Otherwise, we wouldn't need so much of it. I mean, are we capable of destroying matter in our body?
      • Re:Water (Score:3, Funny)

        by pipingguy ( 566974 )

        Water is HEAVY -- seven pounds a gallon. We blow quite a bit of it just dragging it around

        I always wondered why no one ever invented dehydrated water.
  • by Judg3 ( 88435 ) <jeremy@pa[ ]ck.com ['vle' in gap]> on Friday July 23, 2004 @10:35PM (#9786426) Homepage Journal
    But if it helps you to survive a few days longer, that could mean the difference between life and death - you'd be able to ration your water reserve longer and still be able to eat.

    Though I wonder why they didn't make the filter finer to filter out the urea.. Would it cost to much? Be to large?
    • Urea is too small (Score:3, Informative)

      Urea is very small molecule only a bit bigger than water. Even if you did have a membrane that could filter it out - it would take a very long time for enough water to diffuse across into the food.
  • by James_G ( 71902 )
    Why not try some Dehydrated water [buydehydratedwater.com]?
  • But (Score:4, Interesting)

    by l810c ( 551591 ) * on Friday July 23, 2004 @10:36PM (#9786435)
    What if you don't have to piss? You can't drink water to make you piss, because you don't have any.

    I'm not letting someone else hydrate my food.

  • Hmm... (Score:5, Funny)

    by iamdrscience ( 541136 ) on Friday July 23, 2004 @10:37PM (#9786441) Homepage
    I would like to outfit every coffee machine where I work with one of these filters so that I can pee in the coffee and not get in trouble (again). Satisfying for me, but still delicious for them. It's win-win!
    • From the movie Band of Brothers (not sure which part) :

      "You know there isn't a single soldier in Easy Company who'd double time it up and down Currahee just to pee in that guy's coffee."

      Well now you can without the double time!

  • Cheap Clean Water? (Score:5, Interesting)

    by Alphanos ( 596595 ) on Friday July 23, 2004 @10:37PM (#9786445)
    Just how effective is this filter at cleaning water? If it is cheap enough to be mass produced for soldiers' food, then it would be incredible for humanitarian purposes if it cleans water well. Many parts of the world cannot easily clean their own water.
    • by mabu ( 178417 ) * on Friday July 23, 2004 @10:39PM (#9786460)
      Just how effective is this filter at cleaning water? If it is cheap enough to be mass produced for soldiers' food, then it would be incredible for humanitarian purposes if it cleans water well. Many parts of the world cannot easily clean their own water.

      *cough* It's being sold to the military. Who said anything about being "cheap?"
    • by l810c ( 551591 ) * on Friday July 23, 2004 @10:42PM (#9786484)
      I know it doesn't really make a difference, but the more I think about it I would just rather piss in a filter and make water. Then have drinking water and water to add to food. That just has a kind of cool factor. It just seems different then sticking the wanker in an MRE and letting loose.
    • by jerde ( 23294 ) on Friday July 23, 2004 @11:12PM (#9786683) Journal
      Just how effective is this filter at cleaning water? If it is cheap enough to be mass produced for soldiers' food, then it would be incredible for humanitarian purposes if it cleans water well.

      I think it works by osmosis [wikipedia.org], so it won't work just to clean the water: the water is drawn across the membrane into the food because the salt concentration is higher on the food-side.

      If you were to remove the food, and try to use the pouch empty, nothing would happen: the water would not flow across the membrane.

      This is why reverse-osmosis filters require some sort of pump to create pressure against the membrane, to force the water through.

      - Peter
      • Peter's posting is the first technically interesting comment I've seen here, because it differentiates these filters from the more common type.

        Basic filtration is a fairly well-solved technology - campers can buy yuppie-priced water-filters that can turn pond scum into nice clear safe drinking water as long as the problems are bacteria, giardia, dirt, etc. rather than soluble chemicals, and they help on some of the chemicals as well. They won't fix overdoses of salt, or heavy metals, and most of them won

  • Is it really so hard to get a truck filled with water bottles or something to troops? Or even airlift water bottles in? What about morale? Of course one's morale is going to fall (understandably) when you're drinking your own urine!
    • Often, troops are operating places where airlift is just not available. This would be really useful for those guys who sit well in front of the front (when we have those) on a mountain top listening to/messing with enemy radio transmissions--a C-130 would be a little conspicuous. Trust me, the idea fills me with horror and loathing, but if it keeps you alive (and hidden), it might be worth it. Might.
    • Is it really so hard to get a truck filled with water bottles or something to troops?

      Yes, in fact it is really hard to get food & water ( & fuel & ammo) to troops. An army is only as fast as it's supply lines. As was evident and highly reported in the push to Bagdad last year, the troops moved much faster than the supply lines and ran short on food and water. Logistics is a Huge part of any military.

  • by bobhagopian ( 681765 ) on Friday July 23, 2004 @10:40PM (#9786467)
    As disgusting as it sounds to rehydrate a meal with urine, at least it's "clean" (in the sense that you won't get sick from it).

    But dirty water? If you're in the middle of Iraq, I suspect the water may itself pose a health risk. I can't drink the water when I visit third-world countries, and I'd certainly be worried if our troops were exposing themselves to disease.
    • Illness is caused by bacteria, viruses, fungus, and the like. All are bigger than water molecules. So you make a filter that is fine enough to filter them out, but let the water through.

      As for how well this particular one works, I dunno, but they can be made to work amazingly well.
  • by blanks ( 108019 )
    Pissing into a ramen noodles cup is not my idea of a meal.
  • And i've been using unfiltered urin for cooking.
  • Better? (Score:3, Interesting)

    by Johnny Mnemonic ( 176043 ) <mdinsmore&gmail,com> on Friday July 23, 2004 @10:41PM (#9786480) Homepage Journal
    So if you use urine, does it taste worse? Or better?
  • by B4RSK ( 626870 ) on Friday July 23, 2004 @10:42PM (#9786485)
    Great, another awesome reason to go and sign up right now.

    Bleh. :(
  • Good Example.. (Score:3, Insightful)

    by Wes Janson ( 606363 ) on Friday July 23, 2004 @10:43PM (#9786493) Journal
    Of a technology developed for combat that could be an enormous benefit to humanitarian efforts around the world. If cheap and reliable enough, this could save hundreds of thousands of lives.
    • That's the usual way of how things sometimes work. If it doesn't kill, maim, burn, freeze or radiate soldiers, it might just be good enough to apply to civilians. Think of computers, radar, ARPAnet, etcetera. All stuff made by the military but applied for civilian uses later on.

  • Nah (Score:3, Funny)

    by evronm ( 530821 ) <evronm@dtcin c . net> on Friday July 23, 2004 @10:44PM (#9786499) Homepage
    Would you eat food cooked in your own urine?

    Nah, that would piss me off.

    Sorry... somebody had to...

  • According to the article, a day's food supply weighs three and a half kilograms (roughly 7.5 pounds), and this dried food technology can reduce that weight to 0.4 kilograms (0.9 pounds). My question is of where soldiers are going to find a whopping 6.6 pounds of urine per day in the middle of a desert. I admittedly don't know how many pounds of urine I produce daily, but I certainly don't think that even our highly trained fighting forces can produce more than a pound each per day. These P-meals (The P stan
  • Given the choice of the two I'd take the urine over the dirty water, I know urine's normally sterile unless there's a urinary tract infection present.

    And thanks to a recessive gene, I can't taste it anyway!

    I know someone's about to reply with "And how did you find that out?", so before you do, ask if you really want to know the answer.
  • ..It's still higher quality than McDonalds and Burger King combined.
  • I think Fry [gotfuturama.com] has the best review of what it probably tastes like: "What's the worst thing that can happen... ewww, it's like a party in my mouth and everyone is throwing up."
  • by Centrifuge ( 734021 ) on Friday July 23, 2004 @10:55PM (#9786594) Journal
    This is just an attention (advertising) ploy. Sure, you could use urine, but it would be stupid to do so, since the salt and urea in urine would increase dehydration. If you were that short of water, the last thing you would want to do is eat; especially if it would make you even more dehydrated. A soldier could go days (weeks even) without food, but only 2-3 days without water. Using mucky water, however, makes more sense. It sounds like the new MRE package has a filter similar to the portable water filter I carry in my backack on hiking trips. It was not cheap, though, so I am guessing that most of the research is to look into how to make the filter as inexpensive as possible, so an MRE supplied with one would not go for $100 or more. Centrifuge
  • "Join the army and you'll see,
    You can eat all you can pee!"

    (A friend came up with this yesterday while we were talking about the article.)
  • Currently the membrane is too course to filter out the urea so prolonged use results in kidney damage.

    But it does make me start to wonder how long it will take until we have stillsuits.

  • by iamdrscience ( 541136 ) on Friday July 23, 2004 @11:09PM (#9786658) Homepage
    So now MREs taste like piss instead of tasting like shit? I'm not sure which is preferrable to be honest.
  • by bigbigbison ( 104532 ) on Friday July 23, 2004 @11:11PM (#9786674) Homepage
    The important question is, "Is it low carb?"
  • by Dausha ( 546002 ) on Friday July 23, 2004 @11:12PM (#9786678) Homepage
    Okay, here's a reason why the US Army would like to reduce the amount of water consumed by soldiers. It seems people are under the impression that soldiers haul all their own gear and consumables. Not quite.

    We use vehicles to accomplish the logistical feat of transporting soldiers, equipment and water. The US Army calculates that the average soldier consumes something like five gallons of water daily. No, not just for drinking--hygiene, cooking (i.e., field mess facilities), etc. This figure increases for desert operations, for obvious reasons. Considering that five gallons of water is 40 pounds, and considering that a division comprises something like 10,000+ soldiers, then we are looking for something on the order of tons of water required daily. What's more, most of that water will need to be purified. So, the goal here is to reduce the burden on the military's logistical infrastructure by having the soldier consume less water. Sure, it's probably an expensive experiment that will be met with failure.

    What's interesting is this is not the first time there's been a *big* experiment. In the '40s, when we were fighting another crazy ideology or two (fascism, national shintoism), some nut thought that we could train our soldiers to consume less than the required amount of water--especially for desert operations. The idea there was to reduce the burden to the military's logisitical infrastructure by having the soldier consume less water. What's disappointing is this: the human body requires a minimum amount of water to operate. The Army learned that lesson by watching dozens (I've heard as many as hundreds or thousands, but that seems a tad high) of soldiers died disproving the experiment. I think the loss of human life was more expensive than the loss of a few tax dollars. Besides, I think the government wastes money in several other areas that should be reined in first.
  • Sweat and tears (Score:3, Insightful)

    by Gary Destruction ( 683101 ) * on Friday July 23, 2004 @11:15PM (#9786695) Journal
    Wouldn't sweat and tears work if there was enough to rehydrate the pouch? They're both made of salt water. What about saliva?
  • by FauxReal ( 653820 ) on Friday July 23, 2004 @11:16PM (#9786704)
    Engineer Ed Beaudry was quoted by the New Scientist as saying that the body would not find using urine to rehydrate food toxic in the short term, but in the long term it would cause kidney damage.

    Well that finally explains my highschool's cafeteria food...
  • Obligatory (Score:5, Funny)

    by Boyceterous ( 596732 ) on Friday July 23, 2004 @11:50PM (#9786875)
    Urine the army now!
  • Inelegant (Score:3, Interesting)

    by danharan ( 714822 ) on Saturday July 24, 2004 @12:48AM (#9787127) Journal
    It seems there is a different filter for each ration. And it's not a great filter, either:
    Hydration Technology of Albany, Oregon, which makes the membrane, says soldiers should only use urine in an absolute emergency because the membrane is too coarse to filter out urea.


    The body will not find this toxic over the short term, says Ed Beaudry, an engineer with HTI, but rehydrating food this way in the long term would cause kidney damage.


    So... why not give every soldier a really good filter that both filters out urea and can be reused?

    Of course, the army is not necessarily known for trying to find low-cost solutions...
  • Filtration (Score:3, Informative)

    by Trailwalker ( 648636 ) on Saturday July 24, 2004 @07:42AM (#9788209)
    As every backpacker knows, lightweight, portable water filters have long been available.

    Here is selection [rei.com] .

    Whether these could be used under combat conditions is another question.
    • Osmotic potential (Score:3, Interesting)

      by DarkMan ( 32280 )
      The problem with a separate water filter is that you need some means to force the water through the filter. (The stuff you don't want is too big to get through).

      A typical standalone filter uses gravity, and it very, very slow. (note that the typical crappy 'water filters' desinged for tap water don't cut it for swamp water).

      Practical reverse osmosis filters use pumps to generate a pressure difference to make the thing work in sensible time. That's a power requirement, and more weight.

      The trick that's
  • Fremen! (Score:3, Funny)

    by Tancred ( 3904 ) on Saturday July 24, 2004 @12:52PM (#9789318)
    Only a matter of time before soldiers are issued stillsuits. :)

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