Sam's right. It's a still, and so "distills" the water.
FWIW, what won't be removed, and you're likely not to encounter in backcountry water sources are VOC's (volatile organic chemicals), as these will begin to evaporate before (or with) the water, condense on the hood of the still and run down to the catch basin. Other than activated charcoal which works on some chemicals, there is not much, to my knowledge, that backpackers have available to them that will remove all chemicals from backcountry water.
Another SOLAR option, for pre-filtered fresh water, not contaminated with chemicals, is SODIS (solar disinfection) if you are NOT on the move, or possibly are on the move in a large enough vessel (pack rafting???, i guess it's kayaking nowadays.) to perform SODIS.
Just hang a clear bag or jug of pre-filtered water in direct sunlight for about 6.0-6.5 hrs and voila' the UV wavelengths in the sunlight will make point defects in microbial DNA/RNA making self-replication of the little buggers impossible.
Any issues with the type of plastics being used? I'm the wrong one to address this question. Perhaps someone else will help out with this one. Can, for example, a Platy be used? My guess is "yes", but i would like an authoritative response from someone else familiar with the characteristics of the 7, or so, types of plastics available that are used for containers.
Not sure why the 6.0-6.5 hr time is recommended. Perhaps, and i'm guessing here, is that some plastics and glass, to a degree filter out various wavelengths of UV light.
I know from very simple personally conducted laboratory experiments that such statements that plastics and glass do NOT allow any UV light through are FALSE. Each semester, when i was a senior undergrad and then a grad student i would demonstrate this with students taking their first microbiology course.
Exposing properly innoculated media in both glass and plastic closed petri dishes for varying lengths of time (20min to 2hr) in front of the lab's closed windows on a sunny day would result in no growth of the E. coli innoculate, depending upon how long they were exposed to the sunlight. [Sorry, i can't specifically recall the minimum time that produced no growth - it's been over 30yrs.]
The "controls" (plural - each student's, plus my own), similarly innoculated, but not exposed to sunlight, would show growth.
Would i personally drink water "purified" by either solar distillation or SODIS? Answer: Yes. Have i tried either method? Answer: No.