What Is Chlorine Dioxide Disinfection?
Chlorine dioxide (ClO₂) disinfection has unique advantages: it can reduce the formation of chlorination by-products such as trihalomethanes in water; when ammonia is present in water it does not react with the ammonia, so its oxidation and disinfection action are unaffected; it can kill pathogenic microorganisms in water; its disinfecting action is not affected by the pH of the water; the residual chlorine in water after disinfection is stable and long-lasting, giving it strong resistance to re-contamination; it can remove color and odor from water without forming chlorophenol smells with phenol; its removal of iron and manganese is stronger than that of chlorine; and its aqueous solution can be produced and used safely. Its disadvantages are: chlorine dioxide is explosive and must be prepared on site and used immediately; preparing low-chlorine chlorine dioxide is relatively complex and its cost is higher than other disinfection methods; the raw materials for preparing chlorine dioxide are sodium chlorate and hydrochloric acid, which are oxidizing or corrosive substances and also pose storage and transportation safety problems; and the disproportionation products of chlorine dioxide can cause hemolytic anemia and methemoglobinemia and other toxic reactions in animals.
Chlorine dioxide is a powerful bactericidal disinfectant developed in the United States in the 1980s. Through long-term scientific trials by the U.S. FDA and EPA it was confirmed as an ideal disinfectant for sterilization, deodorization and disinfection in health care, food processing, food preservation, the environment, drinking water and industrial circulating water, and it is also a safe, efficient and broad-spectrum powerful bactericide recognized by the WHO. China has approved chlorine dioxide as a disinfectant for use in the disinfection of food and beverage processing equipment, pipelines, food and beverage processing water, tableware, drinking water treatment, etc. In production and daily life, its disinfection of water and air has attracted particular attention.
As a fourth-generation bactericidal disinfectant, chlorine dioxide, compared with the previous three generations of disinfectants, features broad-spectrum, high-efficiency killing of microorganisms along with high safety, and is widely used in the disinfection field. At present, water plants using chlorine dioxide to treat drinking water are increasing around the world. However, it must be noted that it also has shortcomings; there is domestic and international controversy over the toxicity of chlorine dioxide by-products, which remains to be further studied and confirmed.
