AquaStar - Surface Aerators

The AquaStar is the culmination of a three year research and development effort, decades of field experience and ongoing development resulting in it being optimised for Australasian conditions. Modern computer-aided design has been employed to reduce the power consumption of the AquaStar while increasing oxygen transfer. Particular attention has been devoted to making the AquaStar effective and highly efficient over a wide range of power intensities. It is suitable for high rate processes as well as low rate applications. All installations are field tested, providing our firm with unrivalled data and experience on transfer efficiencies in climates ranging from the tropics to alpine.

Our in-house manufacturing capability has ensured the design is optimised to deliver reliable long term performance. Sophisticated strain gauge testing has been employed to ensure that the AquaStar delivers robust long term performance despite arduous field conditions. Many installations have remained in service for well over 25 years.

The AquaStar vertical shaft surface aerator is available in a fixed bridge or floating configuration. Both configurations provide suitable access for maintenance and inspection. The floating configuration has a wide footprint and a low centre of gravity ensuring a stable and safe work platform capable of safely carrying all operational and service loads.

Design Advantages

• AquaStar impeller has a unique patented design to optimise mixing rates and deliver superior oxygen transfer efficiency.
• Suitable for applications ranging from high power and high aeration intensity to low power intensity applications such as lagoons.
• The folded impeller blade profile prevents ragging or fouling, even when used with unscreened wastewater
• Tip speeds of the impeller are less than 7m/s inhibiting shearing of fragile activated sludge flocs.
• Reliable with minimal maintenance and low long term operation costs

The design of the AquaStar impeller has been optimised to deliver not only superior oxygen transfer efficiency, but also the widest turndown range. Oxygen transfer can be reduced to 60% of the design maximum by simply varying the impeller immersion. This can be achieved without adversely impacting the oxygen transfer performance. Adequate mixing is able to be maintained at the lowest impeller operating levels. The impeller performance is also speed sensitive, enabling the use of variable frequency controllers to vary the oxygen transfer for fixed liquid level applications. This also enables the oxygen transfer turndown of variable liquid level installations to be further increased.

The AquaStar can be fabricated in galvanised or epoxy coated mild or stainless steel to suit the requirements of individual installations. The folded impeller has been designed to minimise welding and hence residual stress to ensure maximum life expectancy. It has eight blades to minimise pulsation, each with an upswept lower section, welded to a central shaft on the underside of the spray deflector disc. The impeller is non-ragging, even when operated in fluid containing fibrous material including unscreened sewage.

Floating surface aerators are subject to substantial dynamic forces which can lead to metal fatigue. Through our extensive research and development programme including extensive strain gauge testing, the AquaStar’s superior design ensures lasting reliability.

The AquaStar’s design characteristics include:

• Even distribution of loads and stresses,
• Connections designed to take full advantage of structural strength of members,
• Optimised weld details to avoid stress concentrations,
• Allows for simple, convenient site assembly and routine maintenance, and
• Carefully selected gearboxes to suit forces generated by the AquaStar.

Additional AquaStar Options

• Half or full-maintenance platform around the drive assembly
• Adjustable impeller depth for oxygen transfer turn down
• Variable speed for oxygen transfer turndown
• Guide posts and motion dampeners for floating aerators
• Mist deflectors for reducing spray and aerosols
• Guide vanes to provide stable operation i.e. no vortexing in shallow lagoons
• Foam-filled pontoons to prevent ingress of water in the event of rupture

• Treatment of raw sewage
• Activated sludge systems
• Intermittent aeration systems
• Oxidation ditches
• Industrial wastewater
• Chemical oxidation
• Gas stripping
• Open water aeration
• Fish farms
• Aerobic Digestors