Self Aspirating Aerator

The TORNADO family of Sub-Surface Aerators delivers excellent oxygen transfer and high mixing efficiency to a wide range of wastewater treatment processes in any climate.
From extended aeration to activated sludge to lagoons and oxidation ditch applications, the TORNADO aerator’s rugged but efficient design maximises treatment performance while minimising energy consumption. This unique product mixes and aerates all or part of a basin. The TORNADO aerator is available in several versions:

Self Aspirating Aerator – aerates on its own by aspirating air from the surface and injecting it beneath the surface. Available in sizes from 2 to 100 Hp (1.5 to 75 kw).

Blower Assisted TORNADO Aerator – adds a separate small blower to the Self Aspirating TORNADO® aerator to force even more air down the inlet and into the wastewater. This process produces high oxygen transfer and mixing, up to 10% better than self-aspirating models. Available in sizes from 2 to 100 Hp (1.5 to 75kW).

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Main Features
Maximum Oxygen Transfer and Mixing
Proven Performance
How It Works

Ruggedness You Can Depend On

Your treatment plant is much too important to get snagged with product failures. That’s why the  TORNADO Sub-Surface Aerator/ Mixers offer many years of minimal maintenance and flawless operation. Some of the main features:

The Motor: The motor on your TORNADO is by far the most rugged on the market. It provides you with dependable operation in the severe environments of treatment plants, including the dampest, dirtiest, hottest or coldest plants.
Motor Coupling: A flexible coupling is used to take up any misalignment between the aerator and motor shafts, eliminating the potential for failure problems.
Motor Mount: A stainless steel motor mount with two pins allows the aerator to be easily rotated from nearly vertical to nearly horizontal positions, for maximum performance. But at the same time, it is designed to allow removal of either the motor or the aerator, for ease of maintenance.
The Propeller: Unlike others, our propeller is made of stainless steel for long lasting performance.
The Shaft: Our shaft is precision machined of heat treated solid stainless steel, supported by two bearings, at the top and at the bottom, inside a unique bearing support and shaft protection tube assembly. This design provides maximum stability, vibration free operation, and unmatched extended life.
The Bearings: The 100,000 hour- rated bearings are of the tapered roller design that would take up all thrust loads from the propeller, without transferring any part of it to the aerator shaft, coupling, motor shaft, or motor bearings. The bearings operate within a grease lubricated environment and are sealed to protect them against water splashing or submergence.
The Bearing Support and Shaft Protection Tube: Made of stainless steel, the patented tube serves to support the bearings and protect the rotating solid shaft. Seal modules are used to protect the bearings from the environment.
The Draft Tube: The draft tube, which serves to channel the air into the water, looks simple. But after extensive research and field experience, it has undergone several design changes to insure that it provides maximum air flow with minimum pressure drop. You get the most aeration and mixing for the least amount of energy; all below the surface of the water without spraying or splashing.

Every component in the TORNADO® Sub-Surface Aerator/Mixer is designed with one objective in mind: the optimum delivery of oxygen into the water and its complete mixing with the water. The benefit to you is substantial savings you can count on.


  • The Motor: Each motor used on your TORNADO® is energy efficient, certified to meet global standards, and sized for best performance with other components. This means more of the energy consumption goes to deliver oxygen.
  • The Propeller: After almost twenty years of experience and thousands of TORNADO’s around the world, AEROMIX engineers have learned that not any propeller can do the job effectively. That’s why, they designed each TORNADO® model with a unique propeller that converts the incoming air stream into very fine bubbles in the water and pushes them away for maximum residence time and maximum zone of oxygenation.
  • The Draft Tube: The draft tube, which serves to channel the air into the water, looks simple. But after extensive research and field experience, it has undergone several design changes to insure that it provides maximum air flow with minimum pressure drop.

Today, there are thousands of TORNADO® aerators/mixers operating at more than 3000 treatment plants in more than 80 countries. It has been proven time and time again, some for almost 20 years.

The field proven TORNADO® delivers dependable and economical performance in almost any condition, and provides superior performance in a wide range of applications.

It is simple to direct aeration and mixing toward a deficient area with the angle adjustment locking bolts. It allows for optimal horizontal mixing velocities and fine bubble-residence time time.
It is fully adjustable whether mounted on a float, bridge, or wall. It allows for aeration and mixing of any basin and tank regardless of depth or shape.

Tornado® aerators mix and aerate horizontally, effectively treating large shallow basins.TORNADO® aerators mix and aerate horizontally, effectively treating large shallow basins.


Air may be introduced near the surface of the water, below the surface, or near the bottom of the aeration tank. A mixing action gets the oxygen throughout the water and brings the microorganisms into contact with the dissolved or suspended organic matter.

Our TORNADO® products introduce the air and perform the mixing below the surface of the water, hence they are referred to as Sub-Surface Aerators / Mixers.

TORNADO® Sub-Surface Aerators / Mixers deliver oxygen in one of three ways depending on the type or series:

The TORNADO® SA Series Self Aspirating Aerators/Mixers.
The SA series comes in a variety of aeration and mixing capacities. Very simply, a TORNADO®Self Aspirating Aerator/Mixer consists of a motor, a draft tube, and a propeller. When the propeller rotates, it pushes the water forward, creating a low pressure zone at the propeller hub. This draws air through the air inlet hole, down through the draft tube, until it reaches the propeller. The rotating action of the propeller mixes the air stream with the water resulting in tiny bubbles. The air-water mixture is forced away from the propeller, traveling vertically and horizontally- downward then upward, to the right, to the left, and forward.

The motor on the SA series typically operates at 1800 RPM for 60 Hz applications and at 1500 RPM for 50 Hz applications. The TORNADO® SA series is available in a variety of sizes from 2 to 100 HP (1.5 to 75 KW).


The TORNADO® BA Series Blower Assisted Aerators/Mixers
For applications requiring higher level of oxygenation, a blower is added to the SA Series to force additional air down the inlet hole. The blower uses a small motor, typically from 2 to 10 HP [1.5 KW to 7.5 KW].

The BA series is capable of delivering up to 38% more oxygen into the water and up to 10% more mixing action than the conventional SA series.