Which process is often used to disinfect wastewater before discharge?

Chlorination is a commonly used process for disinfecting wastewater prior to its discharge into the environment or for further treatment. This method involves the addition of chlorine or chlorine compounds to the wastewater, effectively killing or inactivating harmful pathogens such as bacteria, viruses, and protozoa. The use of chlorine as a disinfectant is favored because it is relatively inexpensive, widely available, and effective at achieving a high level of microbial kill.

Once the chlorination process is complete, it is essential to neutralize any residual chlorine before the treated wastewater is released, as chlorine can be toxic to aquatic life. This is often done using sodium bisulfite or other dechlorination agents.

In contrast, filtration is primarily a physical separation technique focused on removing solid particles rather than disinfecting pathogens. Aeration, while important for promoting biological treatment by increasing oxygen levels for microorganisms, does not specifically target disinfection. Boiling, though effective for disinfection in small-scale settings, is impractical for large volumes of wastewater treatment and is not a standard practice. Therefore, chlorination stands out as the most appropriate and effective method for disinfecting wastewater before discharge.