Why is distillation more important than simply boiling? Are there scenarios which imagine massive quantities of nonbiological contaminants? Or simply poisonous biological byproducts, like tomain (sp?)
Distillation is superior to boiling because it can eliminate biological and many other contaminents such as heavy metals and other toxins.
Usually boiling water won't do such.
There are several biologic agents that are heat-resistant, for example botulinum and anthrax spores, and S. aureus exotoxin. It takes at least 280 degrees F to for 20 minutes to kill them. Boiling under pressure is the only way to achieve those temperatures. That’s why non-acidic foods like tomatoes or other vegetables have to be canned in a pressure canner rather than a simple boiling water bath.
“Why is distillation more important than simply boiling?”
Boiling kills bugs fine, but leaves behind things like toxins, lead, arsenic, chemical weapons, selenium, and any toxins the bacteria/fungi have left behind. A filter will get particulates but not bad stuff that dissolves in the water (antifreeze, for instance).
Distillation removes most of that, boils the water to vapor, transports the vapor, condenses it. Energy intensive, though.
The issue with distillation *and* boiling is FUEL. Eventually you can/will run out of fuel, or will be foraging far afield for it. Even it it is available, obtaining it will consume your valuable time. In terms of cost-effectiveness and overall effectiveness I can't recommend the Katadyne "pocket filter" highly enough - with a pore size of .2 microns, it's one of the most serious water filters on the planet.
Also, I can't recommend highly enough the use of calcium hypochlorite to sanitize water (after its been filtered).
Regarding distillation, I recommend using Mother Nature's own distillation process (aka. collecting rain water).
1) Collect rain water
2) Pre-filter the rain water through a cotton cloth
3) Filter that water through a TEOTWAWKI-quality water filter
4) Purify with bleach that has been made from calcium hychlorite.
Regarding sanitation:
1) Have a "sanitation plan" in place
2) Have a couple of bags of lime ready to use
3) Understand the rules for making and locating latrines
4) Be prepared to deal with diarrhea (knowing "Oral Rehydration Therapy" can save lives).
5) Strongly enforce basic sanitation habits among everyone in the group.