This Lifestraw functions pretty much as I imagine the stillsuits would. It is a portable personal water filtration device where you just dip one end of the straw into a water source then suck on the other ‘suction’ end. The water you get out of this would be safe to drink as it filters down to 0.2 Microns which translates to 99.9% of bacterias, viruses and parasites.
The stillsuits in DUNE function in the same way. It has multiple layers which absorb the sweat moisture and urine from its wearer and through a process of filtration, cleans the precious water which is stored in pockets and reabsorbed by the wearer through straws in the neck of the suit. Of course the world in which DUNE takes place on the Planet Arrakis which is a harsh and dry dustbowl.
I can foresee all military infantry in the future will have one such filtration device in one form or the other. It is just so much more practical than lugging around a water canteen.