Essential Water – Treatment / Purification
This is our third installment on water and there is a lot to cover. You can’t last long without water but ingesting dirty or contaminated water is counter-productive. Some diseases like cholera are water borne and preventable as long as water is treated. If you have had a chance to read Dale Comstock’s book American Bad Ass, he narrates one time on patrol with a group of Afghans who thought drinking from a stagnant pond with goat feces floating in it was a good idea (apparently they were thirsty). Needless to say, they spent several hours afterwards expelling fluids from both ends as a result. They lost more fluid than they ingested, so while trying to re-hydrate, they effectively de-hydrated themselves.
Let’s look at this chart from the CDC as reference (http://www.cdc.gov/healthywater/pdf/drinking/Backcountry_Water_Treatment.pdf)
Man, that is hard to read – those government guys must have super eyesight. Click on the link for a legible version. Bottom link up front [BLUF]: boiling water is best but if not feasible, use a combination of filtration and chemical treatment. When boiling water, bring it to a rolling boil for a minute (longer at higher altitudes). Boiled drinks are quite popular in the developing world as raw water is not suitable for drinking / you can die as a result of drinking raw water. Boiling water takes fuel so gather extra wood for the fire…. But before you boil:
Avoid or remove debris and large particles. While there are several micro porous filters on the market specifically designed for campers, the military, or any outdoorsmen, you can begin by removing large particles by filtering raw water through a cloth. Even a t-shirt or bandana can filter out many particles or insect larva that you may not wish to ingest. For extremely dirty water, remember that your filter may clog up quickly and you will have to back-flush it or replace it with a new membrane (or clean t-shirt). Boiling water with a lot of suspended solids might actually dissolve the solids into solution so this is always a good first step to prevent complications.
Let it settle. Many sources recommend filling canteens from running water as the water is usually oxygenated but just note that running water can suspend solids. While still water might be undergoing biological processes, particularly anaerobic processes, many of the large solids quickly settle out and with time, even fine solids will drop to the bottom. You can pour off the clear top layer and leave the silt and sediment behind. Now you can boil the water and be fairly confident that your water is safe to drink.
But if you are on the move and can’t stay still too long, you can use chemical dosing. In the military we used iodine tablets (spoiler alert – leaves a bad taste in the water, you can clear that out by adding vitamin C or ascorbic acid) but several other chemicals are available. The CDC chart above recommends Chlorine Dioxide over Iodine. ClO2 can also be purchased in tablet form usually one small pill per quart. Bleach (unscented) can also be used: two drops per quart. If my math is right, a gallon of bleach could treat over 30,000 gallons of water so that seems to be a pretty cheap and effective method of treating drinking and cooking water for a family of four for years. Remember you have to let the chemicals work (Iodine tablets need about 30 minutes, ClO2 takes longer, see directions for any product you purchase) but agitating the water actually helps the chemicals mix better and adds oxygen so you can fill your canteen(s) add the chemicals and then continue to march while the chemicals do their work. If you get the chance, let the treated water settle before you drink just to be on the safe side.
There are several ceramic filter and pumps on the market designed for the outdoorsman. I have mentioned a ceramic microporous filter straw before as a cheap (about $25 as of this writing) and lightweight (weighs 2 oz) piece of kit for your Bug Out Bag. It works by you sucking through it. If that bothers you, then check out the MSR MiniWorks EX Microfilter which works mechanically and can pump a liter or more a minute (costs about $75 as of this writing and weighs about 1 pound). We have partnered with Life Saver and they offer several water filtration devices, you can check the out here.
One concern is that over time the filter material can become a culture medium for contaminants. But you can follow the instructions on how to clean the item after use and these concerns should be minimized. There are larger and more expensive filters that you may wish to consider for your safe haven although I hope you find some spot that has a good source of water near your permanent homestead (a productive well) so you have a steady supply of raw water to filter / treat. The closer that supply is the less work you have to do to bring it into the home (but a gravity fed system is best).
I saw some UV treatments being promoted on the web and one in particular advocated simply placing water in a clear plastic bottle and letting it sit in the sun for several hours. This is apparently a method approved by WHO for undeveloped countries where sanitary water treatment is otherwise unavailable. Shaking the bottle increases dissolved oxygen which also inhibits or kills many harmful anaerobic bacteria. The process can be accelerated by placing the bottle on a reflective material (it heats up quicker). I also saw many people trolling this method stating that toxins could leech from the plastic. Personally I would prefer to use glass containers if I have them but in a pinch, plastic is lighter and not prone to breakage. This seems to be a viable method of treatment if you have no other means of treating raw water.
De Oppresso Liber