So yesterday I discussed water filtration and some of the facts and myths that surround that topic. Today I will finish this section with water collection, treatment and sterilization. Perhaps there are some myths here that I can tackle as well.
So for starters, I guess that we need to gather water before we can treat it so assuming that there is no lake, stream river or other readily available water source, how do you find it? Being that water is priority the first, you should be making some effort to find a sustainable water source. However, covering exactly how to do this is a topic for another article. I will cover a few incidental water sources that you can exploit when on the move or when looking for a more reliable resource.
Incidental water can help to stretch the water that you have and supplement it occasionally but it is far from reliable. The first is dew. Dew collects on surfaces in the cooler evening hours and will be gone soon after the sun rises. You can towel this up and wring it into a container or tie rags around your ankles and stroll around until they are saturated. Once wet, you can wring them into a suitable container and continue until the dew is gone or evaporates. Dew will be easier to collect from smooth surfaces like cars, windows and large rocks. It will also collect on large flat leaves or other similar surfaces. Never collect the dew from the surface of poison plants as some of the toxins may be present on the surface and will contaminate your water. With a trash bag you can collect large amounts of water by tying it over a dew covered branch and shaking the limb. If left in place the heat of the sun will evaporate water from the plants leaves so it can condense in the bag. Again, do not use this method with plants that contain toxins.
The second Incidental water is rainfall. Rain is not always a reliable source but it does allow you to collect massive amounts if you are prepared for it and have the ability to start collecting it quickly. Some times the rain starts and stops very quickly so you have to have a plan and put it into action at the first sign of precipitation. One of the best ways to collect rain in a survival situation is with a tarp, poncho, or space blanket. Everyone heading out doors should have one of these options with them at all times in the wilderness. If not then you can resort to laying out any and all pieces of plastic that you can find such as trash bags and potato chip bags. They are not ideal but in the game of water collection every drop counts.
The third incidental water is snow and ice. I don't have any lab data for snow and ice so ill just leave it at that. Most pathogens cannot survive snow and ice and when melted it is usually considered safe to drink but if you have the means, it would definitely benefit from some form of additional treatment. So what do you do after you have collected this golden nectar? Do you drink it or treat it? Lets look at the lab data again.
For this section of the test the Norwegian School of Winter Warfare collected incidental water from rain fall and tested it against the sample collected earlier. The water may not be from the same source but testing like this gives a margin of comparison for the two untreated samples. Results were surprising in that they still contained some of the same contaminants as the sample water. How? I do not know as I fully expected this rain water to be good to drink. Perhaps the contaminants are too low to do a body any harm or perhaps not. In any event, incidental water could certainly benefit from further treatment.
So armed with this data and the information from the previous post, it would seem to me, that any and all water collected in an emergency would benefit from some form of treatment. So I will quit talking about collection and talk about treatment and ways to make that water, wherever you collect it, safe to drink.
Water contains many contaminates such as pathogens, toxins and even minerals, many of these contaminates can be harmful if consumed by humans in large capacity. Pathogens are the main source of concern in a wilderness survival situation and toxins are a major concern in an urban survival situation. That is not to say that one is not present in the other environment, they certainly are but they are not the primary threat. I will focus mostly on the wilderness environment.
Pathogens are further divided into virus, cysts, bacteria, and parasites. Many pathogens are microscopic and therefore can fit through tiny surfaces such as fabric and even poorly constructed water filters. such as the tripod filter (pictured below). Pathogens can soak into the fabric layer and essentially bypass the filter media all together. It would be much more effective if the three layers were made of plastic bag or tarp and buckets or soda bottles would be the best option. Many pathogens are also resistant to chemicals and can survive in extremely cold temperatures but are not usually present in snow and ice.
There are a few means of treating water for both commercial and emergency uses. I will list them but I am not going to go into much detail on all of them. Many of these terms are used incorrectly on the web so I thought that I would clear the air and get us all on the same page before discussing some of these methods in detail.
Desalination- Removes the salt from sea water
Reverse osmosis- Evaporates and re-condenses water leaving the contaminants behind.
Filtration- Passes water through a filter media to strain or otherwise remove contaminants.
Disinfection-Removes or destroys harmful bacteria and microorganisms
Sterilization- Sterilizes harmful bacteria and microorganisms so they cannot reproduce in your body.
I am only going to discuss the last three focusing on the last two because I discussed filtration in part one of this post with some good detail. Commercial filters are rated in microns, A micron as it relates to filters, is the size of the opening that the contaminate can pass through. A 5 micron filter has smaller holes than a 10 micron filter etc. The accepted standard for an emergency filter is 0.2 microns. These contaminants vary is size, length, and width, but 0.2 is small enough to catch most if not all of them. There is a good, more detailed explanation here if you want more information.
Disinfection kills the harmful microorganisms but usually leaves them present albeit dead, in the water and this will not hurt you. There are two accepted forms of disinfection and they are heat and chemicals.
Heat is probably the most effective way to treat water, it is easy to do and very effective. Heat does not remove any suspended solids so muddy dirty water will remain muddy and dirty unless they are also passed through a filter of some sort. Even filtering through a t-shirt will make the water much more palatable. But even if you don't filter it...it will be dead and safe to drink even if it tastes like crap as long as there are not any non-organic contaminants in the water. Non organic contaminant cannot always be removed but reverse osmosis is the most reliable method in those circumstances.
On the topic of heat, there are many misconceptions about how much heat to use, So lets put those rumors and bad info to rest once and for all. Bringing water to a boil will kill 99.9% of all organic pathogens. Giardia cyst will die at 60 deg C (140 F) and Cryptosporidium dies at 65 deg C (149 F). Water will boil at 14,000 ft at 86 Deg C (186 F) and at 10,000 ft at 90 deg C (194 F). At sea level water boils at 100 deg C (212 F). So even at 30,000 ft water will boil at 71.1 deg C (160 F) which will still do the trick...RUMOR SMASHED! These are not my assumptions, it is just science. Furthermore the manual for Naval Preventative Medicine (P-5010) states that you must bring water to a rolling boil before it is considered safe for human consumption. In short, like they taught us at the NSWW, "big bubbles no troubles." So for all those that say you have to boil the water for 1-5-10 minutes, that is not required. I always bring mine to "Big Bubbles" and have never had a problem and I have drank from some pretty suspect water sources.
It is worth mentioning that you do not need a container to boil water. In the picture below we simply dug a bowl shaped hole, lined it with plastic and then put in some grass, moss or leaves to keep the hot rocks from burning the plastic. Hot rocks will boil water in a matter of seconds. Here also, are the lab results from water boiled with rocks against our control sample. I think that you will find the results most impressive.
Another method of disinfection is chemical treatment of your water. Again this method does not remove anything it just kills whatever is living there. So again this is ineffective for toxins that are are usually present in water after disasters and floods. You have been duly warned.
Some common chemicals are crystalline iodine and iodine tablets , chlorine dioxide tablets , as well as liquid iodine solution, liquid betadine solution, and liquid chlorine bleach. I wont get into how to use these methods, there is plenty of information available for that. What I will say is that these products put chemicals into the body that are not normally meant for human consumption so prolonged use could have adverse affects. Use sparingly in an emergency, you do not have to practice with these these methods either, just follow the directions on the bottle. Also keep in mind that the temperature of the water will have an effect on the time it takes to thoroughly treat your water. Some directions have you double the dose to drink the water in half the time. Remember that these are chemicals so less is best in my opinion.
The last option that I will cover is sterilization. Usually this method is accomplished with some form of UV radiation. This UV radiation from either a clear container in the sun or from a UV sterilizer pen
simply make the pathogen unable to reproduce. I have heard that this is desired because it allows your immune system an opportunity to develop antibodies much like a vaccination. I have seen no medical or scientific data that supports this claim so I wouldn't bet on it. However, this is a very fast and effective way to make water drinkable but there are so many variables that it is not something that I will fully trust if I have any other options. The biggest variable is suspended solids. These organic contaminants can attach themselves to microscopic solids in the water and essentially hide in the shadows from the UV radiation. This renders the light useless. If you filter the water first than you can minimize the risk but it would take a commercial filter of 0.2 micron to eliminate the risk altogether. I have used this method and I have never gotten sick as a result. I think that is worth mentioning. They do run on batteries which is not desirable but in an emergency they could certainly save your bacon.
There is also a school of thought that says you can expose your water to bright sunlight and the UV radiation will do the same thing. Just remember that the UV light is not as focused and the time allotted for this method is so variable that it would be almost impossible to gauge how long, is long enough. I have not personally used this method because I have not had too. I suppose that its a good tool to keep in your mental tool box but is also carries a lot of risk and I would not recommend it.
With that said I will conclude this series on water but I want to thank again, the Norwegian School of Winter Warfare for the pictures and the training that I received there. And I want to thank the Marine Corps Mountain Warfare Training Center, Mountain Survival Course for making their references public like the winter survival manual from 2002 that I used as a reference throughout this series.
For a very thorough article on water purification my good friend Robert Munilla at PracticalSurvivor.com has a great series that you should go check out HERE. He discusses many of the methods listed here and some insightful information that goes well beyond the scope of this article.
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Thanks and be well, Norseman