In this post I’d like to cover water purification and filtering. It’s highly possible, especially if you’re trying to survive in a wilderness area, that the water you have access to may be cloudy with sediment, or if it is clean, it may still have harmful bacteria and germs in it, such as cryptosporidium and giardia. You must have clean water if you plan to drink it. There are many excellent systems and treatments for purifying your water. The two major methods include: tablets/drops; and filters and filter bottles. Make sure you read the label or instructions to determine what the system treats; some filters may only remove sediment, or heavy metals, rather than bacteria. Try to make sure whatever you’re buying removes cryptosporidium, giardia, heavy metals, sediment, and chlorine. Also, look for something called a micron rating on the package. A micron rating measures the size of the particles or organisms that may be in the water, on a scale of 0.5 to 5. The lower the micron rating, the smaller (and the less) particles are allowed to pass through the filter. For instance, my Bota Bottle Outback filter has a micron rating of 2, which is very good. The main ingredient in many filters is charcoal. For drops, it is usually iodide. Many drops also include a ‘taste remover’ to cover up the unpleasant taste of iodide which is left behind. Finally, boiling water will also kill most of the germs in it; however, you risk losing some of it to evaporation.
I’d like to illustrate some water purification items which I personally use. As I have assembled my gear piece by piece, I have purchased two different types of tablets. The first are Portable Aqua iodide tablets, 2 of which will treat a quart of water in 30 minutes. These are for lightly contaminated water-they don’t inactivate crypto. I also have in use U.S. Military issue Chlor-Floc purification powder packets, made by Rothco. One small packet will treat 1 liter in about 10 minutes. These are general disinfectants, which kill giardia, but not crypto. They are also useful for de-sedimentation of cloudy water. I carry both of these in the small pocket on the side of my canteen pouch.
I also have in use two different filter bottles: the Bota Outback (2 micron rating), and the Clear 2 Go filter bottle. Both of these remove crypto and giardia, as well as 99% of all microbes. Advantages are that these are simple to use; just fill them up, and squeeze the water out through the filter. They also provide superior water to the tablets; no bad taste, and they remove more germs.
Several products which I’d to obtain and test in the future include: the SteriPen, which uses brilliant ultraviolent light to kill harmful microbes. Sawyer also has a wide variety of products and systems for water purification, which boast fast rate of flow; a 0.10 micron rating for bacteria and a 0.02 micron level for viral; and it is the only filter which traps viruses. They also have excellent info on their website about water purification. Finally, Katadynhas a full line of water purification technology, including desalination equipment, for those of you who live near the ocean or boat. Although this list is by no means exhaustive, hopefully it gives you an idea of some of the major technologies out there for water purification.