Tennessee Wastewater Operator Practice Exam

What is used to promote the transfer of dissolved oxygen (DO) into the liquid?

1. Diffusers

2. Mechanical aerators

3. Settling tanks

4. Activated sludge

The correct answer is: Mechanical aerators

Mechanical aerators play a crucial role in promoting the transfer of dissolved oxygen (DO) into wastewater. They function by agitating the liquid and increasing the surface area exposed to the atmosphere, which facilitates the absorption of oxygen into the water. This is essential because many biological processes in wastewater treatment require oxygen to effectively break down organic matter. Essentially, mechanical aerators can take various forms, including paddleAerators or surface aerators, and are designed to mix and aerate the contents of the treatment basin simultaneously. By doing this, they ensure that microorganisms, which rely on oxygen for aerobic digestion, have an adequate supply for their metabolic processes. Keeping sufficient levels of dissolved oxygen is vital for the health of these microorganisms and the overall efficiency of the treatment process. Other options such as diffusers can also introduce oxygen into the liquid, but their method is different from that of mechanical aerators, which provides a more direct agitation approach. Settling tanks are used for the separation of solids from liquids after treatment, while activated sludge refers to a method that utilizes microorganisms to degrade organic material within the presence of oxygen but does not inherently transfer oxygen into the water. Hence, mechanical aerators are identified as the primary technology for oxygen transfer in wastewater treatment facilities.