Simple Ways to Purify Drinking Water in Emergencies In normal activity (times of low stress) the average person needs about a gallon of water a day.
He basically says boiling water is the best way and the way to go. I guess it is the simplest method and doesn't require a $100 filter or whatever. Back in the day, people didn't have life straws and such, so I guess boiling was the way they kept their water semi-safe.
If your boiling, it's a good idea to filter with something any way. Charcoal would be my choice.(and may be a coffee filter. )
Boiling will kill pathogens. It may or may not help with inorganic toxics. It will do nothing for suspended solids, so filtering will be desirable if the idea of mud in your stomach turns you off. Charcoal may or may not remove toxics, that will depend entirely on the material. Now, if you condense the boiling vapors and aerate the condensate, you will have no problems other than fuel to do the boiling.
I'm tinkering with a solar still using a large fresnel lens . this one doesn't give the focal sharpness I want , but Im not giving up.
it does not need to be a truly fine point. This is a 3X4 linear fresnel lens (meaning it focuses down to a short line, not a point). If you read the gauge, it is almost hot enough to melt lead, (which was my aim.) I'm over 500° and that is far above what is needed to boil water.