Cl02 for disinfection of drinking water causing bad odor

In some water distribution systems we use Cl02 for disinfection.

Drinking water users often complain about the odor of the water. 

Enclosed you can find an article from y. 1992, describing the situation, we could describe it as typical for our systems. 

The users in many cases describe the cat-urine odor, gasoline or organic solvent odor. The drinking water seems to be free of any volatile organic compounds that could cause it.

The odor complaints are associated with new carpeting and redecorating  the drinking water users’ homes. 

I am asking for help and more recent scientific explanations of the situation, the risk assessment  for public health  and looking for the appropriate solutions.

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Taxonomy

• Public Health
• Chlorine Dioxide
• Chlorination
• Chlorine Dioxide Treatment
• Disinfection

9 Answers

1. I have read this only today and thus could read all answers, since there is no volatile matter in water, smell from such compounds looks remote. High dose of chlorine, sometimes can smell and it is also not pleasant smell. It is possible that smell of vinyls and lot more used in furnishing may be responsible for this smell being recognised as cat urine smell, where as it could be chlorine smell due to high dose. 

   To avoid such situation is to have product that maintains free residual chlorine to about 0.5 mg/L (ppm) continuously. I have developed a unique product called Chloritard, proper pouch of chloritard once suspended into overhead water tank, maintains free residual chlorine to about 0.5 ppm for a period of one month, after one month, replace the pouch. This product is being used by many in India successfully for last 25 years or more and there is no single failure once proper pouch is selected.

   V. M. Kulkarni

2. The cat urine smell is probably being caused by free ammonia. CL02 doesn't bind with ammonia and this can be a major issue, as well as nitrification could be occurring. When dosing Chlorine instead of Chlorine dioxide, the chlorine is able to bind with ammonia to form chloramines, might be worth taking this into consideration.

   Also, I'm surprised there are no free volatile organic compounds present, as you say the odor complaints are associated with new deco and carpeting. A major source of man-made VOCs are coatings, especially paint and protective coatings.

3. The other problem with chlorine dioxide is that its reduction products are chlorite and chlorate, which are listed in the WHO Guidelines for Drinking Water Quality at 0.7 mg/L for each. It is also difficult to maintain a residual of ClO2.

   Some commenters below suggested removing the chlorine dioxide with granular carbon. That would significantly reduce the disinfection efficacy.

4. I am far from an advocate for chlorine dioxide.  It is a toxic material, which certain companies promote its use outside its usefulness.  Its use as a disinfectant in the presence of ammonia is also a disadvantage.  Because it doesn't bind with ammonia, this becomes free to allow bacterial growth on pipe surfaces within a biofilm.  (Don't always believe what is said about the effectiveness of ClO2 and penetration of slime).  I have come across a situation where bacteria was growing in the biofilm.  When bacteria were released into the water the bacteria disintegrate in the presence of the ClO2 causing the water to have an "off odour".  ClO2 has no effect on iron bacteria which results in metallic tastes in water.  If the waters are metallic (iron) tasting, they are usually safe to drink.  If there is a mild smell or taste of drains, then this may be unsafe and water boiled.  Using filters will often remove these tastes.  It must be remembered that these filters do require changing after the recommended period.

5. The consensus was that the odors were gas phase reactions (in the home air) between chlorine dioxide purging from water with vinylcyclohexene which is a butadiene dimer formed in some carpet adhesives.

6. Better go for Silver Ionization and Copper Ionization method to avoid odour and bad taste.Both Methods are cost effective and less harmfull and controlled dosage is possible

   1 Comment

   1. Good for legionella but not proven to be rapid broad based disinfectants like chlorine is.

7. Activated Carbon is the best after a ClO2 treatment in drinking water. The ozone treatment is better then ClO2. Change the gas!

8. live test results

9. avoid the use of all chlorine based products. Use EcolClearProx, a 100% biodegradable stabilised hydrogen peroxide, approved for human drinking water in Europe. Easy to use, no toxic byproducts, easy to control, easy to measure. economically in use and cost. effective. No risk for public health. Cheap installation, only a dosing pump and a sensor.

   1 Comment

   1. Not proven to be effective as rapid broad based disinfectant like chlorine is.

      3 Comment replies

      1. Show me the CT data for bacteria, virus, protozoa.

      2. you think we got a PT5 approval for free with a package of cookies?

          

      3. says who? are you familiar with my peroxide?