Disinfection constitutes a critical step in sewage and wastewater treatment, as improper disinfection directly exacerbates environmental water quality pollution. Among the prevalent disinfection approaches, this paper focuses on three widely adopted methods—chlorination, ozone disinfection, and ultraviolet (UV) disinfection—analyzing their respective advantages and limitations. Details are as follows:
1.Chlorination Disinfection
Chlorination primarily utilizes agents such as liquid chlorine and sodium hypochlorite. Its disinfection mechanism relies on the rapid formation of hypochlorous acid (HClO) in water. Hypochlorous acid, characterized by a small molecular size and neutral charge, readily penetrates bacterial cell walls to inhibit and destroy cellular structures, ultimately leading to bacterial death and achieving disinfection goals.
Advantages
Strong disinfectant efficacy: Chlorine-based disinfectants exhibit robust bactericidal activity.
Cost-effectiveness and simplicity: The agents are reasonably priced, and the operational principle is straightforward.
Residual bacteriostatic effect: A sustained residual chlorine concentration is maintained post-dosing, preventing bacterial regrowth and subsequent severe water contamination.
Online monitoring: Total residual chlorine can be monitored via Online Total Residual Chlorine Analyzers, which are commonly employed in drinking water and Medical Wastewater Monitoring for single-parameter detection.
Disadvantages
Environmental sensitivity: The disinfection effect is highly susceptible to temperature and pH fluctuations.
Secondary pollution risk: Chlorine’s inherent toxicity necessitates strict dosage control during transportation and dosing to avoid secondary water contamination.
2.Ultraviolet (UV) Disinfection
Advantages
Rapid disinfection: It requires a short contact time and demonstrates strong bactericidal capacity.
Operational safety and automation: The equipment is easy to operate, supports automated processing, and eliminates the poisoning risks associated with chlorination.
Disadvantages
Lack of residual effect: Unlike residual chlorine, UV disinfection does not provide sustained bacteriostatic action.
High operational costs: UV lamps used in China have relatively short lifespans and are expensive.
3.Ozone Disinfection
Advantages
Strong adaptability: It is less affected by water temperature and pH during disinfection.
Broad-spectrum efficacy: It is widely applicable, not limited by bacterial species, and its bactericidal effect is comparable to that of chlorination and UV disinfection.
No secondary pollution: Residual ozone decomposes into oxygen, avoiding the secondary contamination risk posed by chlorine.
Disadvantages
Bromate formation: Ozone oxidation of bromide-containing water sources generates bromate, a recognized potential carcinogen.
Material corrosion: Ozone damages various materials, with the severity of damage increasing with concentration—for example, causing copper plates to discolor, lose elasticity, or fracture.
