Which substance is commonly used for disinfection in wastewater treatment plants?

Chlorine is widely used in wastewater treatment plants for disinfection purposes. Its effectiveness in killing pathogens, including bacteria and viruses, makes it a preferred choice in many facilities. Chlorine is a powerful oxidizing agent that can eliminate harmful microorganisms from treated water, helping to ensure that the effluent released back into the environment is safe and meets public health standards.

Chlorination is a well-established process that allows for both immediate disinfection and the potential for residual protection, meaning that some chlorine may remain in the water after treatment, offering continued protection against microbial regrowth. Additionally, chlorine's cost-effectiveness and ease of handling further contribute to its popularity in treatment processes.

Other substances, like hydrogen peroxide and ozone, can also be used for disinfection, but they do not have the same widespread application as chlorine in municipal settings due to various practical considerations, such as effectiveness, cost, and residual management. Bleach, while similar to chlorine since it contains sodium hypochlorite, is typically not used in the same way for large-scale wastewater disinfection. Instead, it's more commonly found in household cleaning products.