What method is often used during the disinfection stage of wastewater treatment?

The disinfection stage of wastewater treatment is crucial for eliminating pathogens and ensuring that treated water is safe for release into the environment or for reuse. Chlorination and UV light are commonly utilized methods during this phase due to their effectiveness in killing bacteria, viruses, and other harmful microorganisms.

Chlorination involves adding chlorine or chlorine compounds to the wastewater, which reacts with and destroys organisms that could pose health risks. This method is widely used because chlorine is easily available and can provide residual disinfection as the treated water is transferred to distribution systems.

On the other hand, ultraviolet (UV) light disinfection works by exposing microorganisms to UV rays, which damage their DNA and prevent them from reproducing. This method is advantageous because it does not add chemicals to the water, reducing the risk of harmful byproducts.

Both chlorination and UV light are integral components of disinfection due to their ability to significantly reduce microbial loads, making the choice in the question accurate with respect to standard wastewater treatment practices. Other options such as mechanical filtration, bioremediation, and thermal treatment serve different purposes in the wastewater treatment process but are not typically employed specifically for disinfection.