Aeration Blower

Aeration blowers are of great interest to engineers, suppliers and end users. 45% of wastewater treatment plants use electricity for aeration, and blowers account for more than 55% of the energy used by a typical wastewater treatment plant (WWTP). The right choice of aeration blowers is arguably one of the most important considerations for wastewater treatment plants, as they contribute positively to total cost of ownership, conditioning capacity, maintenance requirements and efficiency – they can improve by up to 25%.

The air supplied by the blower to the aeration basin has several functions. The first is to provide the oxygen needed to metabolize the organic compounds in the wastewater. These organic compounds are called “BOD 5” (biochemical oxygen demand), named after the 5-day test used to measure the concentration of these compounds. Oxygen must be dissolved in the wastewater in order to be used by microorganisms. Diffusers use tiny bubbles to efficiently dissolve oxygen into the wastewater.

When microorganisms convert ammonia (NH 3 ) to nitrate (NO 3 ), additional oxygen is required, a process called nitrification. Nitrification usually accounts for half of the overall process oxygen demand.

The combination of sludge and wastewater in the aeration tank is called the mix. The air provided by the blower creates turbulence in the mix to keep the sludge in suspension. Mixing also keeps the contents of the aeration tank uniform. In many plants, mixing limitations rather than oxygen demand determine the minimum air flow rate.

Most diffusers have an upper limit on air flow to prevent physical damage. Maximum flow rates vary by diffuser design.

KUOSI is a manufacturer and supplier of aeration blowers, please contact us for quotation.

Notes on aeration blower systems

Different facilities have different priorities and needs for their aeration systems, and it can be difficult to know what factors to consider. Here are some things to keep in mind.

  • Technology type (roots, screw, cam, multi-stage, turbine, etc.)
  • Remote monitoring and connection capabilities
  • Energy efficiency and efficiency requirements
  • Service and maintenance requirements
  • Total life cycle cost
  • Noise levels
  • Equipment footprint
  • Ease of installation
  • Plant location and climate

Blowers for wastewater aeration are part of a complex treatment system. The air requirements of the process are constantly changing. Providing a blower that operates at a single flow rate and discharge pressure is unlikely to meet system requirements.

A good design will include consideration of variable process demands, current and future loads, and the impact of environmental conditions on performance. The final specification should define the range of operations that must be covered by the blower system.

Water & waste water applications

  • Anaerobic digestion
  • Activated sludge method
  • Diffusion noise
  • Lagoon noise
  • Membrane bioreactor
  • Sequential batch reactor (SBR)
  • Moving bed biofilm reactor
  • Filter backwashing
  • Biogas
  • Sedimentation tank aeration



The use of a certain air volume and pressure blower air or other gases through the transport equipment and diffusion equipment forced to join the water or liquid process is called air blast aeration, with this purpose of the fan is called aeration blower.

  1. Calculate the parameters according to the actual situation

In sewage plant, model selection of the blower fan manufacturer product samples are given on the standard of performance parameters of the inlet conditions, fan in be used actually is not a standard status, however, when the blower environmental conditions such as temperature, atmospheric pressure and altitude is not at the same time, the performance of the fan will also change, will not be able to direct use of model selection of the design product based on the performance parameters of the samples, It is necessary to convert the performance requirements of the fan into the fan parameters under the standard intake state to select the type according to the actual use state.

  1. Analysis of influencing factors of export pressure

The level of exhaust pressure of volumetric blower does not depend on the fan itself, but the situation of the device after the gas is discharged by the blower, that is, the so-called “back pressure”. Aeration blower has the characteristics of forced gas transmission.

To determine the aeration blower pressure, it is only necessary that the absolute pressure achieved by the blower in the standard condition is equal to the sum of the atmospheric pressure in the service condition, the depth of the aeration tank and the line loss.

  1. Blower air flow factor

When calculating the oxygen demand for sewage treatment, the result is the mass flow rate of oxygen required under standard conditions QM (kg/min), which is then converted into the volume flow rate of air required under standard conditions QV1 (m3/min). If the blower is not used under standard conditions, such as in plateau areas, the air density and moisture content will change. The volume flow rate of air supplied by the blower is the same as in the standard state, while the mass flow rate of the supplied air will be reduced, which may lead to insufficient oxygen supply.

  1. Pay attention to the difference between winter and summer

For the same blower, in winter and summer, the volume flow will not change, but because of the different mass flow of air density will change, that is to say, the oxygen supply will be different.

  1. The basic function of aeration is to generate and promote oxygen to effectively contact with water, provide oxygen when oxygen is constantly consumed by biological oxidation, and maintain a certain concentration of dissolved oxygen in water.
  2. In addition to oxygen supply, it also produces enough stirring and mixing effect in the aeration tank area to promote the circulation of water and make the activated sludge and waste water fully contact and mix.
  3. Maintain a certain movement speed of the mixed liquid, so that the activated sludge is always in suspension state in the mixed liquid.

The pressure of Roots blower is the pressure difference between the air outlet and the air inlet, which is usually called boost pressure. Many fans are marked with pressure on the nameplate. Generally, this kind of wind is the highest boost pressure of the fan, sometimes called rated pressure, which is also the biggest resistance that the fan can overcome.

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