What common disinfection method is used in sewage treatment?

Chlorination is a widely used disinfection method in sewage treatment due to its effectiveness and efficiency in eliminating pathogenic microorganisms. When chlorine is added to wastewater, it reacts with contaminants and kills bacteria, viruses, and other pathogens, ensuring that the treated sewage is safe to be released into the environment or reused. Chlorination is favored for its residual disinfection properties, meaning that it can continue to provide protection against organisms throughout the distribution system.

While ozonation and ultraviolet light are also valid disinfection methods, chlorination is particularly advantageous in many municipal treatment facilities due to its cost-effectiveness and extensive regulatory approval. Ozonation requires specialized equipment and can have by-products that need to be managed, while ultraviolet light relies heavily on proper water clarity and may not be as effective against all pathogens without prior filtration. Aeration, on the other hand, primarily serves to promote the growth of microorganisms that help break down organic matter, rather than to disinfect the treated sewage. Therefore, among the listed options, chlorination stands out as the predominant method used for disinfection in sewage treatment processes.