Centrifugal Blowers

Centrifugal blowers, also known as centrifugal fans, are essential pieces of equipment in water and wastewater treatment plants. They are primarily used for aeration in the biological treatment phase, where they supply large volumes of oxygen to bacteria that break down organic material. They work by accelerating air radially (changing the direction typically by 90°), using the kinetic energy of the impellers to increase the volume of the air stream, which in turn moves against the resistance caused by ducts, dampers, and other components.

• Aeration tanks in activated sludge systems
• Aeration basins in Sequential Batch Reactors (SBRs)
• Sludge holding tanks for agitation
• Filter backwash systems for cleaning filters

• Regularly checking and adjusting the blower speed to maintain desired airflow
• Performing routine maintenance such as lubrication of bearings and checking belt tension
• Watching for warning signs of failure such as abnormal vibrations, overheating, or changes in discharge pressure

• Impeller: The rotating part that increases the kinetic energy of the air. Material selection depends on operating conditions, with stainless steel common for corrosive environments.
• Casing: A protective housing that directs the air flow in the desired direction. It is typically made of cast iron or steel.
• Inlet and Outlet Ducts: These guide the air into and out of the blower. Their size affects the blower's performance and efficiency.
• Drive Mechanism: This could be a direct drive (motor directly connected to the impeller) or belt drive (motor connected to the impeller via a belt). The choice depends on required speed and flexibility.

• Flow rate (cubic feet per minute or cubic meters per hour)
• Static pressure (inches of water or Pascals)
• Desired efficiency

• MasterFormat Section 44 42 13 - Process Blowers applies to specifying centrifugal blowers.

• Howden (model: HC Series)
• KSB (model: Omega Series)
• Ebara (model: DSC/DSCA Series)

• Positive Displacement Blowers: These are simpler and cheaper but less efficient at high flow rates.
• High-Speed Turbo Blowers: These are more efficient and quieter but more expensive and require more sophisticated controls.