>"It's a water filter combined with a thigh master! Two – Two – Two products in one!"
Like Ken commented early on: The Stillsuits from Frank Herbert's "Dune" – sweat, urine and moisture from feces are all recovered and treated in a body-powered suit to allow survival on a desert planet.
How about a series of drinking water stations along popular trails – streams and rivers will be tapped 10 vertical feet above the trail crossing, run through a filter to a spigot for refilling water bottles? A hollow post (made of recycled plastic) can function as the drinking faucet and a several-gallon reservoir so you can fill quickly upon your arrival and it will trickle refill around the clock.
I actually kind of like the idea for some high-traffic areas. How much riparian-zone riverbank is trashed as parties spread out to find spots, each upstream of the other people, to filter their water?
Yeah, I know, it's a a Wilderness Area(TM), blah, blah, blah but I'm one of those who think if you have established campsites (by policy or by practice) bear boxes are a pretty darn good idea, even in a Wilderness Area. They (1) reduce impact on the area (by keeping wildlife diets more natural) and (2) they weigh 8 tons less than each of those trail switchbacks built up of granite boulders.
Edited to respond to Mike >combination pee bottle and water purifier. "Why is this drinking water so warm?!?"
For cavers, all water bottles are bidirectional. The contents are clear on the way in and yellow on the way out of the cave.