Water Treatment

Chlorine dioxide has been used for many years as a means of purifying clean water (in the US since 1944). It has been approved and recommended by the US-EPA as an additive to replace chlorine for environmentally friendly drinking water purification. (For reference, click here)

Its oxidizing ability as a biocide, particularly at high pH, makes chlorine dioxide an ideal choice for clean water purification. Chlorine dioxide is used in pre-oxidation and post-oxidation to remove natural organic components (which react with chlorine to produce trihalometanes (THM), which is a carcinogenic substance). Chlorine dioxide also helps in removing inorganic molecules such as manganese and iron. Chlorine dioxide will react with iron and manganese at any pH by converting it into a hydroxy form which then settles.

In general, chlorine dioxide is more effective as a disinfectant than chlorine when processing pathogenic microbes such as viruses, bacteria, and protozoa. These include cysts from Giardia and oocysts from Cryptosporodia which can cause gastrointestinal infections.

501/5000Chlorine dioxide will also remove and control biofilms contained in the clean water distribution network. Chlorine dioxide can be used at very low concentrations. The amount of pre-oxidation will depend on the amount of contamination in the water, but is usually between 0.5-2.0 ppm. The post-oxidation concentration used was 0.2-0.5 ppm to achieve good disinfection results. Chlorine dioxide is active as a biocide for at least 48 hours, thus ensuring longer water cleanliness.

Chlorine dioxide is excellent for use in all industrial water treatment and purification and communal purification systems. It is also ideal for small water supply systems such as wells and hospitals.


Some of the advantages of chlorine dioxide when used in clean water purification applications are:

  • The main disinfectant
  • Maintain taste and smell
  • Reduces THM
  • Reduces HAA
  • Removes iron and manganese
  • Maintain the nitrification process in the chloramine system
  • It is safer than using chlorine gas
  • effective over a wide pH range
  • Does not react with ammonia-nitrogen
  • Effective at low doses for contaminated systems compared to other biocides
  • Very effective for controlling biofilms and algae


  • Water tank; 100 ppm. Put it in the tank, leave it for 1 hour and then drain it.
  • Clean water disinfection; 0.2-0.8 ppm.
  • Circulating cooling water (continuous dosage); 0.1-1.0 ppm. Inject.
  • Circulating cooling water (intermediate dosage); 0.1-5.0 ppm. Inject.
  • Weekly maintenance of the pool: 1.2 ppm.
  • Pool maintenance daily: 0.5 ppm.
  • Fish pond; 0.01-0.5 ppm.
  • Sanitize surface objects; 20 ppm. Soak or wipe for 5 minutes, let dry.
  • Toilet sanitation; 200-500 ppm. Spray, wipe or rinse and let it sit for 20 minutes. Don’t pour it into the toilet hole.