Another pdf in my series of useful pdfs for travel is a little survival guide which I am working on. It’s a longer chore and so I thought I’d post it piecemeal to keep myself on track. The first item is water purification methods:
There are a few methods: water from plants, chemical treatment, solar still, filtration, etc. I’ve been researching online and trying these out in person. All my sources generally agreed with each other on these techniques, so there doesn’t seem to be too many controversies here.
1. Solar still
Solar stills turn out to be really hard work and the water you get out of them is kind of meager. Maybe it would have worked better in a hotter part of the world. It was good to do the experiment because if I ever actually need it, it will take some investment of time and work.
2. Chemical treatment
My primary source for this was the EPA guide but, again, everything I looked at was in broad agreement on dosages and method. It was all pretty straightforward but probably a good use of ten minutes to see that I had these chemicals and to test them out one time. The chemicals are iodine (2% tincture of iodine) or unscented bleach (6% or 8.25% sodium hypochlorite) or of course made-to-purpose water purification tablets. Probably it will never come up but you never know.
3. Water from plants
I didn’t include any specific guidance on what plants you can get water from and what plants will kill you. There are some general principles in other survival guides and here are a couple useful pages. I did include the method of tying a plastic bag around a branch which worked pretty well for me.
I made a few water filters at home, using the things recommended in the survival guides. As you might expect, using actual things from nature like sand and stones resulted in pretty murky water, although it got clearer the more times I ran it through the filter. Water filtered in this way should still be boiled or otherwise purified to kill off the microorganisms.