We hope everyone is having a good week! When we first started sending these emails, a few people told us they were ending up in their spam folders. So, for anyone who missed our previous edition of the Bushcraft Fundamentals How-To series on water purification a few months ago, here it is!
Back in the day, if you fell off your bike or skinned your knee, you’d probably be plonked on the kitchen counter and have a healthy dollop of TCP slapped on the affected area—cue the screaming as the magic ointment worked its wonders and stung to high heavens. That's how you know it's working! Maybe I was just emotionally scarred as a youth, but the potency of TCP has stuck with me and now plays a large role in my teachings around water purification.
If you want to purify water in the field, you must remember, “TCP Before Vomit!” This little mantra identifies all the contaminants we need to consider while making our water safe to drink.
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T - Turbidity: The floaty bits. In fact, the majority of contaminants in water are attached to these, so if we can remove any floating matter, we significantly reduce contamination. This is where filtration systems such as our Millbank Bag come in—to remove these particles. |
C - Chemical: More prevalent nowadays with the spread of human activity and industry. The only way to deal with chemical contamination that I'm aware of is activated charcoal filters. Activated charcoal is produced under controlled laboratory conditions at higher temperatures, which create larger pores than those in standard charcoal. If you had nothing else, adding some crushed charcoal from your campfire to your filtered water, mixing it in, and then filtering it through a millbank bag will help absorb these chemicals.
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P - Parasites and Protozoa: As living organisms, they are susceptible to heat—exposure to high temperatures for a prolonged period will kill them and render them harmless. Some Hollow Fiber Membrane Filters can also remove these contaminants, such as Sawyer or LifeStraw. |
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B - Bacteria: Another living organism, so heat will effectively kill them, as will some chemical treatments such as iodine or chlorine.
V - Virus: Cholera, dysentery, norovirus, and typhoid can all cause serious illness if left unchecked in your drinking water. Viruses exposed to temperatures of 65°C become inactivated after 3 minutes, but since this can be difficult to monitor accurately in the field, we use a foolproof system.
Once we heat water to a rolling boil, it has traveled through temperature ranges from 65 degrees up to 100 degrees (altitude dependent). By the time it cools enough to be drinkable, it has traveled back down that temperature range, ensuring that any harmful contaminants won’t make us regret our relaxing brew in the woods.
At higher altitudes (above 2,000 meters / 6,562 feet), where water boils at a lower temperature, extending the boil time to three minutes helps ensure full purification. If fuel is limited, heating water to 65°C for at least six minutes can still neutralise most pathogens, though bringing it to a boil always remains the safest and simplest method.
