Port Weller

Retrofit of the aeration system with the O2Max Surface Aerators.


The Region of Niagara operates and maintains fourteen waste water systems that include nine waste water treatment plants, one lagoon augmented with chemical and physical treatment, and four lagoon systems. The total rated full treatment capacity for all waste water system is 87 mgd (329ML/d).

The Port Weller WWTP is a secondary treatment plant and serves the cities of St. Catherine’s and Thorold. The Region of Niagara was looking to replace and upgrade the existing low speed surface aerators at this facility. Since the original aerators had been installed the plant capacity had steadily increased to keep pace with the community development.

The case

The existing conical aerators were limited in aeration capacity. The Port Weller plant, headed by Operations Manager Dan Johnstone, had to replace the aerators, in order to increase the oxygen capacity. At the same time, they had to do this without undertaking major changes to the existing infrastructure or installing new systems that would require large capital investment and result in long construction timeframes.
O2Max Aerator in Operation at Port Weller WWTP Splash Pattern with traditional cone aerator Splash Pattern with O2Max Low Speed Surface Aerator.

The solution

Associated Engineering, acting on behalf of the Region of Niagara, turned to Spaans Babcock and their new high-efficiency O2Max Aerators. The O2Max aerator provides up to 20% additional oxygen using the same size electric motors that are installed on existing aerators. As a result no changes to the electrical system were required. All the existing bridge structures and mechanical supports were also reused.
The increased oxygen transfer rates provided by the Spaans Babcock O2Max aerator now approach the fine bubble aeration rates, without any increased maintenance or operations.

The benefits

With the project implementation and the new O2Max in action, Operations Manager Dan Johnstone had this to say: “Spaans Babcock was there throughout the installation and start-up, making sure everything was in order. Their people were knowledgeable and responsive. The plant operatives were especially pleased with the timely project completion, with minimum disruptions. The new aerators have a noticeably better oxygen transfer performance.”

Replacing existing aerator with the new Spaans Babcock O2Max Low Speed Surface Aerator offers many advantages:

1. Easy and Low-cost retrofit of existing low speed Mechanical Surface Aerators, utilizing existing mechanical supports and electrical power supplies.
2. Increased oxygen transfer by up to 20 %.
3. Innovative open-impeller design of the O2Max, reducing the chances of clogging aerator impeller blades and lowering maintenance costs.
4. The O2Max produces a finer and more uniform spray pattern because of the additional blades on the aerator, promoting greater air contact. This design also eliminates the need for a rotating shroud, increasing the life expectancy of the drives.
5. The O2Max aerator has lower axial and radial forces. This will reduce the loads on the support structure.
6. Bridge mounted O2Max low speed surface aerators provide an easy means for accessing the aerators for maintenance.
7. Easier access for maintenance – aeration tanks would not have to be drained to access equipment located at the bottom of the tank.
8. Because of its lower loads, the O2Max provides steady and vibration-free operation, reducing maintenance and potential outages.
9. Simpler construction, without many maintenance-critical elements found in other mechanical aerators.
10. The installation of the O2Max eliminated the need to provide costly new aeration systems which may require blowers, piping, valves and diffusers.

Installation date:
Region of Niagara
Port Weller WWTP
Associated Engineering
Application: Tanks
Aerator size:
No. of units:
2000 mm
62 kg O2/h
Vertical on a bridge
30 kW


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