Tennessee Wastewater Operator Practice Exam

Which types of blowers are commonly used at wastewater treatment plants (WWTPs)?

1. Centrifugal and rotary

2. Centrifugal and positive displacement

3. Rotary screw and diaphragm

4. Axial and positive displacement

The correct answer is: Centrifugal and positive displacement

The commonly used blowers at wastewater treatment plants (WWTPs) are centrifugal and positive displacement types. Centrifugal blowers are characterized by their ability to move large volumes of air at low pressure. The design allows air to enter the blower at the eye of the impeller and is thrown outward by centrifugal force. This type of blower is often preferred for applications where a continuous flow of air is required, such as in aeration processes where oxygen is delivered to wastewater to promote microbial activity. Positive displacement blowers, on the other hand, function by trapping a fixed amount of air and forcing it into the discharge pipe. They are particularly effective in applications requiring higher pressures and are commonly used in situations where consistent, pressurized air is necessary. This type is beneficial for compressing air for pneumatic systems within the treatment facility or for processes requiring a higher pressure air supply. Both types of blowers are essential in maintaining optimal conditions within wastewater treatment systems, making their use common practice in these facilities.