American Water Works Water Treatment Plant Operator (WTPO) Practice Test

Chloramines are formed when chlorine reacts with ammonia in water, creating a family of disinfection byproducts. When chlorine is added to water containing ammonia, the ammonia combines with the oxidizing chlorine species to produce monochloramine first, and under certain conditions can progress to dichloramine and even trichloramine. This group of compounds—chloramines—describes the byproducts formed specifically from that reaction. Nitrogen trichloride is a specific chemical that can arise in some chlorination scenarios, but it’s not the general term for the byproducts produced when chlorine reacts with ammonia. Chlorine gas is the elemental form of chlorine, not a chloramination byproduct. Nitrogen dioxide is a different pollutant unrelated to the chloramination process.