According to PUR's website and video -- the treatment involves:

1. collecting dirty water in a container
2. adding PUR powder treatment
3. waiting 3 minutes for coagulant to solidify both particulates and dissolved matter into a solid that sinks to the bottom of the dirty water container

4. carefully pouring water through a cloth filter to a second receiving container and discarding the solid matter left in the first water container.

5. wait another 20 minutes for PUR chlorine to treat viruses and bacteria inside the now pretty darn clear water in the receiving container.

6. pour and drink

I can see this for camp use and also when you have 30+ minutes lunch break.