I picked up a LifeStraw when I purchased a box of the Mainstay Emergency Food Rations,and for a long while, it stayed in the bottom of my bear box, untried, untested. Eventually I found it, dug it out and got ready to test it. Then the dog found it. Talk about Disaster Preparation! I heard the chewing sound and rushed into action, rescued the unit, and decided it was salvageable. The LifeStraw is a plastic tube 31cm long and 3cm in diameter. It has a Sieve end, and a mouthpiece end, both originally with a cap. The straw, as you might imagine is operated by placing the sieve end in your water source, and through some rather strong and vigorous sucking is needed to get water flowing, but when it does, you get a steady flow of water.
The way the LifeStraw works is that water that is drawn up through the straw and passes through hollow fibers that fill the tube. This bundled mesh of fibers filter particulates down to 0.2µm across, using only physical filtration methods and no chemical components to either run out, or leach into the drinkable water. The entire process is powered by the suction of the operator, and is reported to be able to filter up to 1000L (264gal) of water safely before clogging up.
Initial models of the filter did not remove Giardia lamblia, but this model is purported to remove a minimum of 99.9% of waterborne protozoan parasites including giardia and cryptosporidium. It is also touted as Removes up to 99.99999% of waterborne bacteria. It as previously stated also reduces turbidity by filtering particles of approx 0.2 microns which significantly improves the quality of water,
You can see the sieve end here, which keeps macro-particles from entering the straw, and for better or worse, after some dog-chewing, this end cap had popped off, exposing the internal fibers in their mesh packing sleeve.
The LifeStraw
did take some practice and perseverance to get going, but when it did, I managed to get some interesting results. I didn't want to take too many risks with my dog-chewed example, (giardia infection will ruin your whole day) so I opted for a more pedestrian testing regime. I chose to filter my fruit-concentrate cordial instead. I found that whilst still coloured, and sweet, the water I drew off certainly did cut the pulp and particles that were suspended, and I managed to drink the whole glass, with some effort. I expect that from a free floating and particulate light source, like a free flowing stream, you'd get swifter hydration. You can de-crud the filter by blowing back through it, expelling the contained water, and self-washing to some extent.
To recover and reseal the unit post-dog gnawing, I wrapped it in a cris-cross of tape, to ensure the seals and tube are air-tight. I think i will try to secure myself a new one, (which due to their awesome business model, then benefits kids in impoverished places) just because having a fully-working one is better preparation than relying on my already weathered and dinged one.
