So, doing some research on water puirifiers (specifically the Berkey filters) and I thought of something. I was watching a show (I believe Man VS Wild) where the guy used a snake skin to hold his pee, and later to drink it. Now that can't have been a pleasant experience but it got me thinking. If you could drink it straight up, why couldn't you filter it first?
So with something like a Berkey, if there was absolutely no other source of water, in a pinch would that work to clean it up and make it a bit more palatable?