Tornado® Sub-Surface Aerators

Print Friendly

With thousands of units in operation around the world, Tornado sub-surface aerators have a solid record of maximizing performance while minimizing energy consumption.

Tornado sub-surface aerators deliver excellent oxygen transfer and high mixing efficiency to a wide range of wastewater treatment processes in any climate. From extended aeration and activated sludge processes to lagoons and oxidation ditch applications, the Tornado aerator’s rugged but efficient design maximizes treatment performance while minimizing energy consumption. This unique product mixes and aerates all or part of a basin.

Learn more about our full line of aerators and aeration equipment.

Tornado blower-assisted aerators

With thousands of units in use around the world, the Tornado family of aerators is the most cost-effective way to improve the performance of your wastewater treatment operation.

The Tornado aerator is available in two versions:

  • The Tornado Self-Aspirating Aerator, which 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).
  • The Tornado Blower-Assisted Aerator, which adds a separate, small blower to the self-aspirating 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 75 kW).

Rental units are also available.

Tornado Design Maximizes Aeration

The Tornado aerator is designed with a large-diameter stationary draft tube with an unrestricted air inlet to produce the maximum amount of aeration and mixing capacity using the least energy. All aeration and mixing takes place below the water surface, eliminating odors from splashing or spraying. No harmful, bacteria-laden aerosols are generated, keeping the treatment process safe.

The self-heating design of Tornado aerators makes them ideal for year-round operation in cold climates. Needing no pumps or other accessories, Tornado aerators provide a self-contained system that saves money in installation and operating costs. Angle adjustments allow optimization of horizontal mixing velocities, mixing depths, and bubble hang time. Tornado aerators have an unmatched all-stainless steel construction, providing excellent corrosion and UV resistance even in the toughest wastewater.

RWL Water’s Tornado sub-surface aerators

There are thousands of Tornado aerators operating at more than 3,000 treatment plants in more than 80 countries.

Tornado Reduces Odors

Tornado sub-surface aeration eliminates problems often associated with surface aeration equipment: spraying, splashing, and misting of structures, equipment, and personnel. RWL Water’s Tornado sub-surface aerators:

  • Decrease the potential for foul odors around the aeration tanks and beyond the plant in nearby communities. This improves employee morale and keeps neighbors happy.
  • Reduce or eliminate the potential for unsightly mess, corrosion of equipment, and damage to structures caused by splashing and misting. This can only decrease operating and maintenance costs and safety hazards.
RWL Water Tornado sub-surface horizontal aeration

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

How the Tornado Works

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

Tornado sub-surface aerators deliver oxygen in one of two ways depending on the version:

  • The Tornado Self-Aspirating Aerator comes in a variety of aeration and mixing capacities. Very simply, a Tornado 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 typically operates at 1,800 rpm for 60 Hz applications and at 1,500 rpm for 50 Hz applications.
  • The Tornado Blower Assisted Aerator is used for applications requiring a higher level of oxygenation. A blower is added to the self-aspirating aerator 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 blower-assisted Tornado is capable of delivering up to 38% more oxygen into the water and up to 10% more mixing action than the conventional Tornado.

Ruggedness You Can Depend On

Your treatment plant is much too important to get tied up with product failures. That’s why RWL Water designs and builds our Tornado sub-surface aerators for years of minimal maintenance and flawless operation. This means your capital budget can carry you further into the future and your annual maintenance expenses will be substantially reduced.

Consider these design elements:

  • The motor: The energy-efficient motor on your Tornado — certified to meet global standards and sized for best performance with other components — is by far the most rugged on the market. It provides you with dependable operation in the severe environments of treatment plants, even in 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. The mount is designed to allow removal of the motor or the aerator for ease of maintenance.
  • The propeller: After almost 20 years of experience, with thousands of Tornado units in use around the world, RWL Water engineers have designed each model with a unique propeller that converts the incoming air stream into very fine bubbles and pushes them into the water for maximum residence time and zone of oxygenation. Unlike other propellers, ours is made of stainless steel for long-lasting performance.
  • The shaft: The shaft is precision-machined of heat-treated, solid stainless steel, supported by two bearings — top and bottom — in a unique bearing support and shaft protection tube assembly. This design provides maximum stability, vibration-free operation, and unmatched extended life.
  • The bearings: Patented sealed tapered roller bearings securely support the aerator shaft, preventing vibration and taking up all propeller thrust loads. This helps extend the life of the motor bearings.
  • The bearing support and shaft protection tube: Made of stainless steel, the patented tube supports the bearings and protects the rotating solid shaft. Seal modules are used to protect the bearings from the environment.
  • The draft tube: The draft tube, which channels air into the water, looks simple. But after extensive research and field experience, it has undergone several design changes to ensure 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 and without spraying or splashing.

Proven Performance

Today, there are thousands of Tornado aerators operating at more than 3,000 treatment plants in more than 80 countries. Their durability has been proven time and time again, with some still running strong after 20 years.

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

  • Angle-adjustment locking bolts make it simple to direct aeration and mixing toward a deficient area. This allows for optimal horizontal mixing velocities and fine bubble-residence time.
  • The aerator is fully adjustable, whether mounted on a float, bridge, or wall. It allows for aeration and mixing of any basin or tank regardless of depth or shape.
RWL Water Tornado aerators in Taiwan

Tornado installation on the Putzi River in Taiwan.

Extensive Applications and Widespread Use

Over the past two decades, RWL Water has evolved into a leading water and wastewater treatment technology company. We have developed products that offer cost-effective solutions in municipal, industrial, commercial, and institutional markets.

Tornado aerators are ideal for applications such as:

  • BOD reduction and removal
  • Odor and algae control
  • Nitrification and denitrification
  • Aeration and mixing in tanks, lagoons, and ponds
  • Aerobic digestion
  • Ice control
  • VOC removal
  • Leachate treatment
  • Aquaculture
  • Fats, oils, and grease removal or separation
  • Revitalizing freshwater bodies — rivers, lakes, etc.

They are extensively used at:

  • Municipal wastewater treatment plants
  • Food processing plants
  • Dairies, wineries, and beverage plants
  • Pulp and paper mills, and textile facilities
  • Refineries, chemical, and petrochemical plants
  • Fish and aquatic farms
  • Animal farms
  • Lakes, rivers, and ponds
  • Military bases

A Unique Aeration Solution to Suit Your Needs

At RWL Water, we have a group of applications engineers devoted exclusively to helping treatment plants, consulting engineers, and contractors. Armed with our internally developed computer software and years of experience, they can help you find the right solution for your unique aeration and mixing application.

Lease and Evaluation Units Available

Lease units are readily available as a quick backup for unforeseen conditions, if your capital budget is limited, or if you would like to evaluate a unit in your particular application. Whatever the reason, if you decide to buy your leased equipment, you’ll get a generous credit for your lease payments.

Contact RWL Water for more information about Tornado sub-surface aerators, ready-to-lease units, or to request a quote.