For a drinking-water treatment plant, disinfection must not only be effective, but also stable and controllable.
For a water plant with a daily treatment capacity of 30,000 cubic meters, any fluctuation in the disinfection process can affect not only an individual piece of equipment, but also the operation of the entire water-supply system and the quality of the treated water.
This drinking-water treatment plant in a county of Qinghai previously used a sodium hypochlorite generator for disinfection. During actual operation, the plant encountered a problem in which disinfection by-products exceeded the required limits, making it necessary to adjust the existing disinfection method.
How to maintain effective disinfection while making chemical dosing more stable and test results more controllable became the key objective of this system upgrade.

Taking into account the plant’s existing treatment process and its daily treatment capacity of approximately 30,000 cubic meters, the project adopted XIUBA chlorine dioxide dosing equipment together with the corresponding disinfectant to upgrade the original disinfection process.
After the new system was put into operation, operators could adjust the dosing rate according to actual water flow and test results, making the disinfection process clearer and easier to manage.
The equipment was installed and commissioned at the water plant. The chemical dosing pipelines, chemical storage units, and metering devices were integrated as a complete system, providing the foundation for continuous and stable dosing.

After the equipment was put into operation, a chlorine dioxide tester was used on site to measure residual chlorine dioxide in the treated water.
The four measured results were as follows:
| Test | Residual Chlorine Dioxide |
|---|---|
| Test 1 | 0.32 mg/L |
| Test 2 | 0.28 mg/L |
| Test 3 | 0.39 mg/L |
| Test 4 | 0.44 mg/L |
The acceptance range adopted for this project was 0.28–0.44 mg/L.
All four test results fell within this range. The minimum and maximum readings were also respectively at the lower and upper limits of the accepted range, indicating that the residual chlorine dioxide level in the treated water met the project’s control requirements.

According to feedback from the project site, after switching to XIUBA chlorine dioxide dosing equipment and the corresponding disinfectant, the water plant achieved good disinfection performance. Residual chlorine dioxide in the treated water met the required range, and all other relevant indicators also met the project requirements.
This upgrade addressed more than a single testing issue.
More importantly, it improved the adjustability and manageability of the disinfection dosing process.
For a county-level water plant responsible for maintaining a stable water supply, whether the equipment can operate in coordination with actual water flow, the existing treatment process, and routine testing directly affects the stability and convenience of subsequent operation.
From experiencing excessive disinfection by-product levels during operation of the sodium hypochlorite generator to achieving compliant test results after switching to a chlorine dioxide dosing solution, this water plant with a daily treatment capacity of 30,000 cubic meters completed a targeted upgrade of its disinfection system.
There is no single water-treatment solution suitable for every project.
An effective upgrade must be configured according to source-water quality, treatment capacity, the existing process, and finished-water control objectives.
Only by linking equipment, chemicals, dosing, and testing into a stable closed-loop system can each cubic meter of treated water leaving the plant be provided with stronger operational assurance.
Note: This article was compiled based on feedback from the project site and on-site testing photographs. Water-quality conditions and process requirements vary among water plants. Specific disinfection solutions and dosing rates should be determined according to on-site testing and professional engineering design.