If you get sick from drinking bad water, you can end up with vomiting and diarrhea, which speed dehydration. So it’s good to understand a variety of ways to make water safe to drink.
The traditional methods of water purification include the use of chemicals such as chlorine or iodine, passing the water through a filter system, or boiling. But there’s another way to remove organic pathogens from water without using any of those methods.
It’s pasteurization. We all know that milk is pasteurized to kill off biological contaminants, but very few people have heard of pasteurizing water to purify it.
Pasteurization is simply the raising of the temperature of the liquid until it is hot enough to kill the biological contaminants such as bacteria, virus, worms and cysts like giardia and cryptosporidium.
The natural assumption is that that’s why boiling is used as a purification method. Well, yes. That’s true. But the surprising fact is that you don’t actually have to bring water to a boil in order to defeat all the bad critters in the water. Pasteurization does not require boiling the water. In fact, you can kill off all the biological bad guys by bringing the water temperature up to a mere 150 degrees Fahrenheit (65 degrees Celsius) and holding it there for 6 minutes. That’s a lot easier than boiling at 212 degrees Fahrenheit (100 degrees Celsius).
Worms and stuff like giardia and cryptosporidium are killed at 131 degrees F (55 Celsius). Bacteria die at 140 degrees F (60 degrees Celsius). And the hepatitis A virus expires at 149 degrees F (65 degrees Celsius). In fact, when milk is pasteurized, the temperature is only 160 degrees F (71 degrees Celsius) and it’s held at that temperature for only 15 seconds.
The benefit of using pasteurization rather than boiling is that it requires less fuel, and a secondary benefit might be that the process is faster so you can process more water in a shorter amount of time.
The obvious benefit of boiling is that you can know when the temperature is high enough, because you see the water bubbling. That’s not the case with pasteurization. In order to know that you have brought the water to a high enough temperature, you need some method of measuring the temperature. A cooking thermometer works well. Or you can use a WAPI, which stands for Water Pasteurization Indicator. This is a transparent high-temperature plastic tube with a blob of wax inside. You place the WAPI in the water and watch for the wax to melt, which it does at 150 degrees F. The WAPI can be reused hundreds of times, by letting the wax cool and solidify so it’s ready for next time. Water Pasteurization Indicators cost less than $10 online from many sources.
One thing to know, however, is that neither boiling nor pasteurization eliminates non-biological contaminants from water. Heavy metals, chemicals and such require filtration to get rid of them. But pasteurization is a faster and more fuel efficient method of water purification to get rid of all the organic contaminants.
So there you go, now you have one more technique you can add to your survival strategies.
Correct.
ReplyDelete