Chlorine Dioxide

Water purification in the backcountry is a vexing problem without a completely satisfactory solution as far as I am concerned. Over the coming months I’ll be discussing several water purification products on this blog.

For the past few years I have been relying almost exclusively upon Katadyn Micropur MP1 purification tablets, which is a chlorine dioxide system.

Hundreds of municipalities around the world use chlorine dioxide technology to disinfect public water supplies. It can be effective against bacteria, virus, and protozoa including Giardia and Cryptosporidium.

I like using Micropur tablets because they are very lightweight and easy to use. Excuse the whining, but I have become annoyed with the weight of pump filters and the effort required to pump water.

Each Micropur tablet treats a liter of water, so getting the dose right is quick and easy. The tablets are individually packaged and sealed, and Katadyn claims a 5 year shelf life from time of manufacturing; an expiration date is stamped along the edge of the packaging strip. Unlike tablets packaged together in pill bottles, you don’t have to worry about the unused tablets losing their effectiveness because of exposure to air. Thus the individually packaged Micropur tablets are suitable for use in seldom used emergency kits or as a light and compact backup for pump filters and other mechanical purification devices.

Scissors or a knife are needed to remove each tablet from its sealed pouch

The instructions on Micropur packaging states that once placed into contaminated water, tablets must “react for 4 hours” before the water is suitable for drinking. Four hours is a long time!

In a separately published information brochure, Katadyn addresses this issue. The EPA demands that the product packaging show only the wait time for cold and dirty water (“EPA Water #2”), very challenging water to treat. In such challenging conditions, Katadyn claims Micropur kills bacteria and virus in 15 minutes, but kills Giardia and Cryptosporidium in 4 hours.

However, in clear, warmer water (“EPA Water #1”), Katadyn claims Micropur kills bacteria and virus in 15 minutes; and kills Giardia and Cryptosporidium in 30 minutes. Take time to read the brochure for all the important details on this topic.

So, one downside of using Micropur tablets is the need for thinking ahead about your water needs. I take full advantage of night camps whenever possible to treat contaminated water for 8 or more hours for use the following day; and while hiking, attempt to have enough treated water on hand when I reach a contaminated water source I intend to take water from, in order to comfortably allow for an appropriate wait time.

Chlorine dioxide does impart a taste to the water, especially if the water is consumed immediately after the treatment time has expired, though the taste will diminish with more time. I do not find the taste particularly objectionable. For me it is far more pleasant than iodine treated water, and doesn’t taste much different than some municipal water I have run across.

3 Comments Add yours

  1. Craig says:

    I have been using the Aqua Mira dros for a few years and love them. They are the best bang for the buck. The mixing is a pain sometimes but if the water is cloudy I can tailor the mix with a couple extra drops. Also the taste is practically non-existant.

  2. Jerry Cagle says:

    I used the aforementioned Micropur tablets this weekend hiking south on the AZ trail from Italian Trap Tank toward SNPE (and on several previous trips). I love the light weight, and was somewhat in tune with the caveats on the wait times in cold/dirty water. I appreciate the clarification, Dave. I too try to take advantage of night camps to let the water sit overnight, but that can be a challenge if you’re in an unfamiliar area and miscalculate the availability of water along your route. I do find the difficulty of opening the packets to be a pain. Fortunately, I haven’t forgotten to bring a knife yet.

    Regarding the taste: I haven’t been bothered by it, as a matter of fact, I hadn’t even noticed it. But then, although I wouldn’t claim it was palatable, I didn’t find the "wheat grass"-like flavor of the water in Italian Trap Tank undrinkable either…

  3. dave says:

    Scissors work much better than a knife for easily and quickly opening the packets. Small folding scissors and the scissors on some Swiss knives work well. I prefer the small and light weight Leatherman Micra multi-tool.

Leave a Reply

Your email address will not be published. Required fields are marked *