Why is the chlorine that I s added to final treated waste water allowed to get used up before it is discharged into a river or lake?

Chlorine is added to final treated wastewater to eliminate harmful pathogens and ensure the water meets safety standards before being discharged. Allowing the chlorine to be used up prior to discharge prevents any residual chlorine from entering the receiving water body, which can be toxic to aquatic life. This process helps protect ecosystems and maintains water quality in rivers or lakes. Additionally, it minimizes the potential for harmful chemical reactions that could occur in the environment.