We are looking for anyone with experience using chlorine dioxide (Clo²)
asked 9 June 2016 asked by Patrick47 (390 points)
In relation to dinking water networks Beware: this is a dangerous product. You need to develop a detailed protocol and consider the following elements ahead of time: - Limiting the risk of degassing at the injection site - Equipment selection -Storage of chemicals and reducing agent - Adequate ventilation and cooling of the storage tank (ClO2 is explosive at temperatures above 40 °C) - Opting for assembly line generation rather than producing it in batches, so as to avoid risks associated with storage. - Personnel training and SCBA on site in case of leak - Environmental protection guidelines or necessary authorization
With respect to drinking water, chlorine dioxide is to be avoided wherever possible. As has been said, it is very dangerous, toxic and explosive. In addition, it has to be prepared using a mixture of hydrochloric acid and chlorite with the risk of later encountering chlorites in the treated water when the dosing is not perfect or there is any error in generating the product. Chlorine dioxide must be produced in a special, dedicated area otherwise any equipment nearby will be damaged by corrosion. In a distribution network, the risk of it reacting with polyethylene pipes is extremely high—it will weaken them and seriously impact the performance of the entire network. Chlorine dioxide was a fad in the 1980s, which unfortunately persists in some quarters where operators prefer to eliminate bad tastes by avoiding chlorine altogether, rather than addressing the source of the bad taste itself. It really is no longer acceptable. For the removal of manganese, there are other techniques such as pyrolusite, for example. In my humble opinion, chlorine dioxide risks far outweigh the benefits when it comes to the safety of drinking water systems.
Many of the comments on ClO2 are true - as a very strong oxidant (second only to ozone) there are many hazards in making and using it as a treatment chemical. Though the same could be said for Chlorine gas or Mustard Gas in WWI - yet it has single handily saved more lives by preventing water borne disease than any other water treatment process and over the 100 years. So back to your question - ClO2 has many advantages over other disinfectants - the first being it does not produce DBP's. It is fast acting and very effective. It does produce negative side effects in drinking water - Chlorite/Chlorate, both of which can cause regulatory issues and must be closely evaluated. ClO2 is used in many applications - cooling towers especially. On firm has received approval to use it to stabilize municipal bio-solids to US EPA 503 regulation standard (www.BCREnvironmental.com). So as with all treatment processes close evaluation of your targeted treatment goals and detailed understanding of the health and environmental risks are part of our jobs in the water profession. Hope this helps
Chlorine dioxide could be the treatment of choice if it oxidizes the taste/odor compounds in the your raw water. Comparing life cycle costs with other candidate treatments - for example ozone, there are safety and byproducts considerations all around. Using in drinking water plants, the reactants are injected and the ClO2 is made in the transfer water, contained inside the reactor and pipeline; never seen or heard of making a tank of the gas in wtp Make the choice from among technologies that will work, usually including pilot testing, get it designed right, and then learn how to operate and control the application and move forward.