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"Lifesaver Bottle" Filters Viruses Out of Water
gihan_ripper writes "British inventor Michael Pritchard has developed a small self-contained filter system that instantly cleans water, removing all particles larger than 15nm. He said that he was inspired after seeing the effects of Hurricane Katrina and the Boxing Day tsunami in 2004; people had to wait for many days to get fresh water and many died from drinking contaminated water. The filter is so effective that it can purify dirty river water and even fecal matter. His bottle will shortly be available for sale from Lifesaver Systems at an expected cost of £190 (approx. $385)."
It's been possible to buy similar "virus level" filters for hiking since at least the 80s. The typical problems are cleaning, and clogging. See Katadyn or your local REI for a variety of samples. Then there's the "$2" (really about $7) LifeStraw, that was advertised on gizmodo 2 years ago... is this just a running theme?
If the filter is small enough to block viruses, then it is so small that even very small 1u particles will clog it. The whole filter system has to be optimized... and they still clog. They claim 1000 liters, but I'm not really buying it. If it really has something to do with distilling, then I'd be more positive, but that's usually pretty darn complex.
Perhaps he's using a teflon reverse osmosis filter? At the price, it's certainly possible. Those take significant pressure, but they would take out viruses. The water has to start pretty clean too or they develop a film which clogs them too. People have tried iodine on them as well... it works for a while. Whithout knowing what this thing is (and the website's no help), I don't think we can really talk coherently about it.
If it is just a filter you can reverse flush and clean and do a variety of other things, but if your filter clogs after a few liters you'll be _very_ unhappy. This is made more difficult by the fact that you're trying to clean out biologicals, which will happily grow in the filter so it clogs up even quicker, and the cleaning is even more important and difficult to do completely. That's why people make throw aways or just add a halogen (chlorene/iodine) to a tub of relatively filtered water (so things can diffuse) and wait an hour.
Most hikers (who bother) use a more coarse filter (for bacteria only). Often these are treated with iodine as well, and perhaps charcoal to remove bad tastes. These keep clogging problems down, and make cleaning somewhat more easy. That's what the LifeStraw is based on.
I hope this is really an advancement, but it has the smell of an ad.
Drinking pee is harder than you think. I speak from personal experience.
I was lost in the Ozark mountains for 2 days without any supplies. The temperature was over 100F and I had almost no water. The little water I did have was exhausted quickly and the next best alternative was my own pee. I became thirsty enough that drinking my own pee was not even a question - it was a necessity (or so I thought).
I removed my flashlight batteries and peed in my flashlight because it was the only thing I had that could hold liquid.
Guess what happens to your pee when you are dehydrated? It's get much more concentrated. So much so, that I think you'll have a hard time drinking it unless you are, literally, getting close to death. Mine was so strong, I couldn't even stomach the smell much less, drink it. I have never been as thirsty in my life as that day and I have never since, been in a situation as dire as that one. Yet, I couldn't drink it.
While it may be an option early on, as dehydration starts setting in, drinking your own pee becomes less of an option as each hour passes by.