Tennessee Wastewater Operator Practice Exam

What is the role of mechanical aerators in a wastewater treatment process?

1. Reduce solids concentration

2. Promote gas separation

3. Enhance DO transfer

4. Control pH levels

The correct answer is: Enhance DO transfer

Mechanical aerators play a crucial role in wastewater treatment by enhancing the transfer of dissolved oxygen (DO) into the water. In aerobic treatment processes, such as activated sludge systems, sufficient oxygen is necessary for the microorganisms that break down organic matter. The mechanical aerators agitate the wastewater, creating surface turbulence that facilitates the absorption of oxygen from the atmosphere into the liquid. This oxygen is vital for the survival and activity of aerobic bacteria, which are responsible for decomposing organic pollutants in the wastewater. By increasing the amount of dissolved oxygen, mechanical aerators help maintain the desired aerobic conditions, promoting efficient treatment and improving the overall performance of the wastewater treatment system. Other functions, such as reducing solids concentration or controlling pH levels, may occur concurrently in various treatment stages, but the primary and most significant role of mechanical aerators is to enhance the transfer of dissolved oxygen, ensuring that the microbial processes essential for effective treatment can proceed optimally.