What is a common method for disinfecting treated wastewater?

• A. Chlorination
• B. Filtration
• C. Mechanical aeration
• D. Flocculation

Answer: (A)

Chlorination is a common method for disinfecting treated wastewater due to its effectiveness in killing or inactivating a wide range of pathogenic microorganisms present in the water. The process involves adding chlorine or chlorine compounds to the treated wastewater, which reacts with the pathogens, ultimately rendering them harmless. Chlorination not only reduces microbial levels significantly, but it also provides a residual effect, which helps to protect the water from potential recontamination if it is stored or transported before use or discharge.

Additionally, chlorination is a well-established and widely utilized method in many wastewater treatment facilities because of its relatively low cost and ease of application. It can be adjusted to target specific contaminants or to achieve regulatory compliance for effluent quality.

Filtration, mechanical aeration, and flocculation, while essential processes in wastewater treatment, primarily serve different purposes. Filtration is used to remove suspended solids and particulates, mechanical aeration is focused on oxygenating the water to enhance biological treatment processes, and flocculation is involved in aggregating particles for easier removal, rather than directly disinfecting the water. Therefore, chlorination is the most appropriate choice for effective disinfection in this context.