Waterworks require that the water leaving the factory contain a certain concentration of disinfectants. The main purpose of adding disinfectants is to kill microorganisms in tap water and water supply pipelines, prevent the spread of water-borne infectious disease bacteria to users, and endanger people's livelihood safety.

According to the "Hygienic Standard for Drinking Water" (GB5749-2022), the routine indicators of drinking water disinfectants include free chlorine, total chlorine, ozone and chlorine dioxide. Common disinfectants include liquid chlorine, sodium hypochlorite, calcium hypochlorite, chloramine, ozone and chlorine dioxide.

01Free chlorine

When using liquid chlorine, sodium hypochlorite or calcium hypochlorite disinfectants for disinfection, free chlorine should be determined.

The "Hygienic Standard for Drinking Water" (GB5749-2022) stipulates that the standard values for free chlorine are as follows: contact time with water ≥30 minutes, limit values for water leaving the factory and at the end of the pipeline ≤2mg/L, residual amount of water leaving the factory ≥0.3mg/L, and residual amount of water at the end of the pipeline ≥0.05mg/L.

02Total chlorine

When chloramine disinfectants are used, the total chlorine should be determined.

The "Hygienic Standard for Drinking Water" (GB5749-2022) stipulates that the total chlorine standard value is as follows: contact time with water ≥120 minutes, limit values for water leaving the factory and at the end of the pipeline ≤3mg/L, residual amount of water leaving the factory ≥0.5mg/L, and residual amount of water at the end of the pipeline ≥0.05mg/L.

03Ozone

When ozone disinfectants are used, the ozone level should be measured.

The "Hygienic Standard for Drinking Water" (GB5749-2022) stipulates that the standard values for ozone are as follows: contact time with water ≥12 minutes, limit values for factory water and terminal water ≤0.3mg/L, and residual amount of terminal water ≥0.02mg/L.

04Chlorine dioxide

When chlorine dioxide disinfectant is used, the chlorine dioxide content should be determined. When using a chlorine dioxide and chlorine mixed disinfectant generator for disinfection, the levels of chlorine dioxide and free chlorine should be determined. Both indicators should meet the limit requirements, and at least one indicator should meet the margin requirements.

The "Hygienic Standard for Drinking Water" (GB5749-2022) stipulates that the standard values of chlorine dioxide are as follows: contact time with water ≥30 minutes, limit values of water leaving the factory and at the end of the pipeline ≤0.8mg/L, residual amount of water leaving the factory ≥0.1mg/L, and residual amount of water at the end of the pipeline ≥0.02mg/L.

The application of Bebur's online disinfectant Analyzer in Waterworks

The Bebur disinfectant online analyzer adopts the electrochemical measurement principle and can quickly and accurately detect the values of free chlorine (residual chlorine), total chlorine, ozone and chlorine dioxide in water. It features simple operation, accurate measurement and easy maintenance. Users can flexibly configure different sensors on site according to their detection needs. The detection data can be automatically recorded and stored, and can also be downloaded.