Which method can effectively reduce the residual chlorine content after disinfection?

Activated charcoal filtration is an effective method to reduce residual chlorine content after disinfection in wastewater treatment. This process relies on the adsorption properties of activated charcoal, which has a large surface area and a high affinity for various chemical substances, including chlorine and its byproducts. When water passes through activated charcoal filters, the chlorine molecules bond to the surface of the charcoal, thereby effectively removing them from the water.

While ultraviolet radiation is an excellent disinfection method that can kill microorganisms without adding chemicals, it does not reduce chlorine levels; instead, it can be used alongside chlorine treatments but does not address the residual chlorine itself. Biological treatments involve microorganisms that can assimilate organic matter but are not specifically designed to remove residual chlorine. Similarly, centrifugal separation is a physical process used to separate solids from liquids based on density differences and does not capture or remove chlorine effectively.

Therefore, activated charcoal filtration stands out as a suitable choice for lowering residual chlorine levels after the disinfection process has occurred.