There is only one maybe 2 mechanical units approved by the EPA as water purifiers. First Need being the most common. It has drawbacks as mentioned. The rest are filters of different degrees. If it were me in this situation I would use the katadyn hiker with a coffee filter over the prefilter.
then I would chemical treat it with MP1 tabs, then I would run the water threw a brita type filter twice to remove chemicals and metals.
The best you can do without a real expensive unit.
A word on ceramic filter elements. They work good but freeze and crack in
winter, got that t-shirt.
http://www.backpacking-guide.com/water-filter-purifier-reviews.htmlHound
