Basic Wastewater Operator Practice Exam

What controls the rotational speed of the air drive biological contactor (RBC)?

1. The amount of suds

2. The water volume

3. The air volume

4. The bacteria growth

The correct answer is: The air volume

The rotational speed of the air drive biological contactor, commonly known as a rotating biological contactor (RBC), is primarily influenced by the air volume. The air drive system helps facilitate movement and rotation of the disks or media that support microbial growth, which is crucial for the treatment of wastewater. When air is supplied to the system, it creates buoyancy and reduces resistance, thus enabling efficient rotation of the contactor, which improves oxygen transfer and enhances the overall biological treatment process. The air volume not only determines the rate of rotation but also affects the distribution of dissolved oxygen throughout the system, which is vital for the aerobic bacteria's metabolic processes. Therefore, manipulating the air volume can directly influence how fast the RBC turns, thereby optimizing the environment for bacterial growth and wastewater treatment efficiency.