Among ozone, ultraviolet light, and chlorine disinfection methods, ultraviolet light disinfection is relatively more environmentally friendly. Its environmental friendliness is reflected in no chemical residues, low energy consumption, and no secondary pollution, while ozone and chlorine disinfection have certain limitations in environmental friendliness.

1. Ultraviolet Light Disinfection

• No chemical residues: UV disinfection kills microorganisms by damaging their DNA or RNA structures. No chemicals are added during the entire process, so no harmful by-products or residues are produced, and no chemical pollution is caused to water or air.

• Low energy consumption: UV disinfection equipment consumes relatively low energy during operation, resulting in minimal environmental impact in terms of resource consumption and environmental pollution.

• No secondary pollution: UV disinfection does not discharge harmful substances into the environment, which is conducive to environmental protection and sustainable development.

2. Ozone Disinfection

• No residues but potential by-products: Ozone decomposes naturally into oxygen after disinfection and does not leave harmful residues on disinfected objects. However, during ozone production—especially when using the corona discharge method—a certain amount of electrical energy is consumed, and by-products such as nitrogen oxides may be generated, which have a certain impact on the environment.

• Potential hazards to humans and the environment: Ozone itself is a strong oxidizing gas. Excessive ozone is harmful to humans and the environment, such as irritating the respiratory tract and damaging plants and some materials.

3. Chlorine Disinfection

• Generation of harmful by-products: Chlorine disinfection produces certain harmful by-products. For example, when disinfecting drinking water, chlorine reacts with organic matter in water to form halogenated organic compounds such as trihalomethanes (THMs) and haloacetic acids (HAAs), which have potential carcinogenic, teratogenic, and mutagenic properties.

• Impact on aquatic ecosystems: If chlorine-containing wastewater is directly discharged without proper treatment, it will affect aquatic ecosystems and disrupt the ecological balance of water bodies.