During sewage treatment, what is the final step before effluent is released into the environment?

The final step in sewage treatment before effluent is released into the environment is disinfection. This process is crucial because it significantly reduces or eliminates harmful pathogens and microorganisms that can pose health risks to humans and aquatic life. Various methods can be employed for disinfection, including chlorination, ultraviolet (UV) light treatment, and ozonation.

Proper disinfection ensures that the treated sewage, now referred to as effluent, is safe for discharge into natural water bodies. It is essential to minimize the impact on the ecosystem and protect public health by preventing the spread of waterborne diseases.

Other methods like centrifugation, filtration, and neutralization occur earlier in the sewage treatment process. Centrifugation is generally used for separating solid particles from liquids, while filtration involves removing larger particles from the wastewater but does not adequately address microbial content. Neutralization adjusts the pH of the sewage to prevent acid or base toxicity but does not eliminate pathogens. Disinfection stands as the final safeguard for ensuring the effluent's safety and environmental compatibility.