Water Treatment Operator-in-Training (OIT) Practice Test

Which component of a wastewater treatment plant is primarily responsible for the removal of solids from the water?

1. Clarifier

2. Bioreactor

3. Filter

4. Chlorinator

The correct answer is: Clarifier

The clarifier is primarily responsible for the removal of solids from wastewater in a treatment plant. This component operates based on the principle of gravity separation, where suspended solids settle to the bottom of the tank, forming a sludge layer. The clarified water, which contains fewer solids, then overflows from the clarifier. In the context of wastewater treatment, the clarifier is essential for separating heavier particles so that they can be removed and processed appropriately, thereby improving water quality before further treatment steps. It plays a crucial role in ensuring that solids do not pass into subsequent treatment stages, which can lead to operational issues and inefficiencies. Other components serve different functions; for instance, the bioreactor is primarily engaged in the biological treatment of wastewater, where microorganisms break down organic matter. Filters are used later in the treatment process to remove remaining suspended particles and microorganisms after primary treatment. The chlorinator is involved in disinfection, ensuring that pathogens are eliminated from the treated water before it is discharged or reused. Thus, the crucial role of the clarifier in solid removal distinguishes it from the other components mentioned.