I don't know if this will discourage you or not, but in the backpacking community this type of gear has been available for decades. Just do a search on Backpacking Equipment and look for water purifiers or water filters. Here is an example:

Water Purifiers

I've used one for years - I think its called First Need. A few years ago, 2 of these units provided all of the drinking water and cooking water for 12 people on a 10-day backpacking trip. Each unit weighs about a half pound, filters down to 0.1 micron, produces a quart of drinking water in less than a minute (hand pump operated), and has a filter capacity of 200 gallons (and has a replaceable filter). With a 0.1 micron filter, your talking ultra pure water - nothing gets through that kind of a filter. At the time, cost was about $60. A good one today can probably still be found for about $75. My unit still works and I keep it in my hurricane supply box.
Cheers,
ED