All collies are dogs but not all dogs are collies. We'll have to agree to disagree on the word usage of "sodium hypochlorite."

The takeaway from below is; 1)ClO2 is more effective than chlorine and its 'bleach' version, 2)while new to backpackers, ClO2 is time tested and, 3) the same can be said for UV treatment.

The water that emanates from water utilities is used/approved for irrigation, human consumption, dumping into surface waters or a combination of all three. Different standards/regulations are involved for the different uses. Municipal water providers generally use a multi-step process which includes sedimentation, biologic breakdown of the waste, filtration and chemical treatment. UV treatment is also being added.

As for municipal utilities trending to the use of chlorine dioxide:

U.S. municipal water systems started using chlorine dioxide in the mid-40’s (Treatment of Drinking Water with Chlorine Dioxide, www.oxy.com). The start time in Europe was about the same. But ClO2 is not without its own problems to include cost, handling safety, and by-products. Still, because of chlorine’s more troublesome human health issues and the subsequent changes in water quality regulations/standards, utilities have turned to ClO2 (ibid). “It is recognized as a superior water disinfectant alternative to chlorine and has become increasingly popular as a water purification treatment. Chlorine is being phased out due to growing concerns over its carcinogenic by-products, principally trihalomethanes (THMs)…In the U.S., the Safe Drinking Water Act and its subsequent amendments over the last 20 years have required dramatic improvments in the quality of municipal drinking water. These stringent new requirements have increased the use of chlorine dioxide in the U.S. while decreasing the use of chlorine as a water treatment chemical.” (Chlorine Dioxide – Water Treatment Technical Report: Chlorine Dioxide as a Water Purification Product and Safe Water Treatment Chemical, www.pristinewatertreatment.com/technical-info.html). More than 15 years ago, the trend was well established, “Approximately 700 to 900 public water systems use chlorine dioxide to treat potable water (Hoehn, 1992).” (EPA Guidance Manual, April 1999 Alternative Disinfectants and Oxidants, www.epa.gov/OGWD/mdbp/pdf/alter/chapt 4.pdf) That trend continues despite the moribund character of utilities. Here in Missoula County, our less-than-stellar (and often, less-than-compliant) wastewater treatment plant has, I think , adopted ClO2 treatment. I know that was the plan which also included the addition of UV treatment and that addition has been accomplished. Virtually all the sources here and others I saw specified giardia when referring to the higher effectiveness of ClO2.

FB