In typical surface water treatment, filtration is followed by terminal disinfection.

In typical surface water treatment, filtration is followed by terminal disinfection.

• A. True
• B. False
• C. They occur concurrently
• D. Disinfection comes before filtration

Answer: (A)

The main idea here is that in a conventional surface water treatment train, filtration serves as the final physical barrier to remove particles and many microbes, and terminal disinfection follows to inactivate any remaining microorganisms and to establish a disinfectant residual for the distribution system. Filtration captures most of the particulates and many microbes, but some may still pass through; applying disinfection after filtration ensures those remaining organisms are inactivated before the water leaves the plant. It also leaves a chlorine (or other disinfectant) residual in the distribution system to prevent regrowth or contamination, which is why this step is described as terminal disinfection. Disinfection before filtration or doing both steps concurrently aren’t how the standard flow is arranged, so the statement is true.

The main idea here is that in a conventional surface water treatment train, filtration serves as the final physical barrier to remove particles and many microbes, and terminal disinfection follows to inactivate any remaining microorganisms and to establish a disinfectant residual for the distribution system. Filtration captures most of the particulates and many microbes, but some may still pass through; applying disinfection after filtration ensures those remaining organisms are inactivated before the water leaves the plant. It also leaves a chlorine (or other disinfectant) residual in the distribution system to prevent regrowth or contamination, which is why this step is described as terminal disinfection. Disinfection before filtration or doing both steps concurrently aren’t how the standard flow is arranged, so the statement is true.