Clean water no matter what
November 18, 2011 5:00 AM   Subscribe

Water: that convenient thing you can't live without. Tell me about a portable desalination / purification device.

I don't need it right now, of course, but I'm curious whether it exists or not. The basic ideas:

* Handheld, portable, or at least carryable
* Something that can filter most anything thrown at it
* Able to put out a household's worth of water in a reasonable period of time.
* Works by hand crank, generator, battery, or something other than standard electricity.
* MAJOR bonus points if it can heat up that water as well.

If this can be bought, where? If this can be hacked, how?
posted by chrisinseoul to Technology (6 answers total) 6 users marked this as a favorite
Might not be what you're looking for, but....

You can use chemistry components to do this. A heat source, 2 beakers and piping that can withstand the water vapor.

Beaker #1 should have the saltwater in it.

Heat the beaker #1 with the piping connected to the top - the water vapor will then go through the piping - and place the other end of the piping on the 2nd beaker, preferably immersed in cool or ice water (as this will help the water vapor condense and collect).

Voila! You have desalinated water.

(To test this, I suggest you MeMail genekelly'srollerskates' who is an actual chemist and could advise you on technique. However, I believe this is a low cost way to have your own desalinator.
posted by glaucon at 5:26 AM on November 18, 2011

Solar still
posted by Tom-B at 6:10 AM on November 18, 2011

Response by poster: Two good answers, but I'm hoping for something a little less labor-intensive, much like a standard electricity generator that runs on gas.
posted by chrisinseoul at 6:44 AM on November 18, 2011

The Katadyn Expedition is (hand) pump based and claims to be able to deliver more than 4L/min.

The Katadyn Drop Gravidyn uses gravity and claims 4L/hour.
posted by Comrade_robot at 6:58 AM on November 18, 2011

I use the Katadyn Hiker (well, actually it's the Pur Hiker before they were bought by Katadyn) and it's worked well for me. It has an adapter that fits the mouth of Nalgene bottles (which isn't a unique feature, but one that I like).

The simplest one that I like is the Platypus GravityWorks (and the similar version by Sawyer). With those, you fill one bladder with dirty water, and gravity does the rest. No pumping.

The MSR HyperFlow is awesome, but you can't let it freeze, and you have to be careful about dropping it, because the filter element uses tiny glass tubes.

None of these require electricity, and they're designed to be portable.

Note: I work for the company linked here; just givin' info.
posted by spikeleemajortomdickandharryconnickjrmints at 7:47 AM on November 18, 2011

Removing salt is very different than removing bacteria. Salt is dissolved so cannot be removed by filtration; you need either to distill or use reverse osmosis to remove salt. Distillation and reverse osmosis also remove bacteria (and pretty much everything), but they're more energy-intensive than filtration, hence less portable.
posted by anadem at 8:04 AM on November 18, 2011

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