Water purifying query:

Has anyone had any experience or insights about the effectiveness of the Purification straw -CR211 – BCB Bushcraft – an iodine/carbon combo straw that treats 50L of water and weights 17 grams? I believe its original intended use may have been for third world environments but not sure.

… after all the comments here. Still doing a lot of reading. Anybody checked the U.S. Army site on water filtering/purification?
http://chppm-www.apgea.army.mil/WPD/CompareDevices.aspx

The Katadyn Exstream Water Bottle is another solution for all inclusive protection.

"P.S. Stop hunting – go vegan and gather instead."

But hunting is gathering, after all, of the best protein available, and free range at that!

… my hunting club, with 7,500 leased, well-watered acres of hills and valley crisscrossed by 100 or more miles of two-tracks and trails.
I'm thinking that is worth my dues whether I kill a deer or two or not …

This is my first post on BPL! I read the BPL store info on Aquamira drops, and also many other posts, as well as received a favorable recommendation from a store. However, I was taken aback by the fact that the product specifically does not make claims for efficacy and by the fact that REI does not carry it. So I have tried to do some independent investigation.

The following page is from the CDC (Center for Disease Control) and deals with the efficacy of various water purification methods. It is worth reading. http://www.cdc.gov/healthywater/drinking/travel/backcountry_water_treatment.html. It states that chlorine dioxide is very effective against bacteria, viruses and Giardia, but only somewhat effective against Cryptosporidium.

However this page does not provide any data showing how long a treatment by chlorine dioxide should take place. Relevant information can be found on the following EPA page: http://www.epa.gov//safewater/mdbp/pdf/alter/chapt_4.pdf

There are charts on that pdf that show the results for various pathogens at various concentration of chlorine dioxide at various temperatures and for various times. "CT" seems to mean concentration multiplied by time. To interpret the results from Aquamira, we need to know the concentration of chlorine dioxide. The 30 milliliter bottle of part A has a 2% chlorine dioxide composition, so that is about 0.6 ml. My research suggests that this solution may weigh just slightly more than water, so each bottle contains.6 gram or 600 milligrams of chlorine dioxide. The bottle is said to hold enough for treatment of (up to) 120 liters. However, I counted the drops in my Part A bottle: 690; that would only be enough for just under 100 liters if the recommended dose of 7 drops is used. Each dose calculates at 6 milligrams per liter (quart). So looking at the tables on the EPA page, it appears that the efficacy of chlorine doxide, even with very cold water, is excellent for everything except Cryptosporidium, where full effectiveness may require a several hour wait for cold water.

By comparison, if you look at the info on Katadyn chloride dioxide tablets at REI, it works relatively rapidly (15 or 30 minutes) for everything except cryptosporidium, which requires a 4 hour treatment for clear water. The packaging information states that it produces a solution of chloride dioxide of 4 ppm (parts per million), which would be approximately 4 milligrams per liter. Aquamira tablets have the same specification, i.e. 4 ppm chlorine dioxide and a 4 hour wait. Given that the liquid drops may be 50% stronger and that they can probably become active in water faster than can a solid tablet, the drops are likely to work faster. On the other hand, if cryptosporidium is a worry and the water is cold, a wait of 3 to 4 hours may be required. Since the Aquamira drop directions call for only a 15 or 30 minute wait period, this may be why they make no water treatment claims and have no EPA certification for water treatment.

Hi David:

Welcome to the forums! I just answered your questions above on the other thread. Feel free to ask as many questions as you like — I know folks here are always glad to help — but please refrain from posting the same questions on multiple threads. Cheers.