Backcountry Water Treatment, Part 4: Ultrafiltration

This video is Part 4 in a series on Backcountry Water Treatment methods, focusing on Ultrafiltration purifiers, also known as the removal of viruses (in addition to bacteria and cysts) from drinking water by size-exclusion. It addresses the claim that viruses are too small to be filtered by hollow-fiber membranes with 0.02-micron ratings, looks at filter options available in this class, and discusses the viral risks in backcountry waters. There are also sections on the health threat of flood waters in a disaster, and the tactic of filtering your water twice for the additional removal of pathogens. Watch the entire Backcountry Water Treatment series here:    • Backcountry Water Treatment   Index 00:21 Is Virus Filtration a Myth? 16:22 Section Summary 17:00 Virus Filters 22:42 Viral Risk Factors 32:42 Filtering the Risk 35:23 Section Summary 36:27 Water Treatment During Disasters 38:15 Tactic of Filtering Twice 41:22 Runt Microbe Theory 43:02 Rogue Pore Theory 50:03 Conclusion