Which statement about prechlorination is true?

Prepare for the American Water Works Water Treatment Plant Operator Test. Study with multiple choice questions, each with hints and explanations. Get ready to excel!

Prechlorination involves adding chlorine to raw water early in the treatment process, at the headworks. The main idea is to achieve disinfection early, reducing microbial load and helping protect downstream steps. It also targets tastes, odors, and aquatic growth by oxidizing odor-causing compounds and inhibiting algae. In addition, the chlorine helps improve coagulation and settling by oxidizing organic matter and destabilizing particles, making flocculation and removal more effective. That combination—disinfection plus control of tastes, odors, and growth, with an added benefit to coagulation and settling—is why this statement is correct. The other options misstate when prechlorination happens or what it does: it is involved at the headworks, it does more than simply reduce chlorine residual, and it is used before settling, not after.