Enhancing aeration efficiency at Rotorua

By September 8, 2025September 17th, 2025Project Report
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Enhancing aeration efficiency at Rotorua WWTP New Zealand with iTURBO®-Blowers

As part of our ongoing commitment to delivering high-efficiency, sustainable solutions for municipal wastewater treatment, INVENT has successfully supplied and commissioned four iTURBO®-Blowers at the Rotorua Wastewater Treatment Plant in New Zealand. The project was executed in close cooperation with our regional partner, Jonassen Industrial Projects Ltd..

Project background

Rotorua WWTP is operated by Rotorua Lakes Council and is a key facility in the Bay of Plenty region, treating both municipal and industrial wastewater from the urban area. The plant currently uses an activated sludge process and is undergoing a major upgrade program to meet higher environmental standards and accommodate future population growth.

One of the major focuses of the upgrade is the improvement of aeration efficiency, which historically accounts for over 50% of the total energy demand in the biological treatment stage. To meet this objective, INVENT‘s high-performance iTURBO®-Blower was selected to replace aging blowers and provide a more efficient and reliable solution.

Scope of supply

Four iTURBO®-Blowers with 160 kW input power to each blower delivering up to 6000 Nm3/hr @ 70 kPa discharge pressure. Fully integrated units to replace aging blowers including:

  • 155 kW high-speed permanent magnet synchronous motors (PMSM)
  • Direct-drive turbo impellers
  • Built-in variable frequency drive (VFD)
  • Integrated Siemens industrial PLC control and communications
  • Advanced monitoring with HD touchscreen HMI
Implementation and results

All four iTURBO®-Blowers were successfully installed and commissioned in 2021. Since commissioning, they have demonstrated:

  • Significant energy savings compared to legacy systems (up to 30% reduction observed)
  • Stable and responsive oxygen supply for the biological process
  • Minimal noise emissions, contributing to an improved working environment (<78 dB(A))
  • Reduced maintenance requirements, with air filter replacements being the only regular service task

The integration into the existing SCADA system enables real-time monitoring, fault diagnostics, and performance optimization, supporting the plant’s operational efficiency and reliability.

Technical advantages of the iTURBO®-Blower

Energy efficiency: Optimized isentropic efficiency and minimal mechanical losses

Compact footprint: Integrated design reduces installation space and simplifies layout

Digital intelligence: Adaptive control algorithms respond to changing load conditions

High quality build: Baked power coated enclosure with full 316 stainless steel fasteners and fittings for long term projection from the sulfurous volcanic atmosphere

Sustainability: Contributes to a measurable reduction in CO₂ emissions and lifecycle costs

Additional projects in New Zealand

Following the success in Rotorua, iTURBO®-Blowers have also been installed at other key wastewater treatment facilities across New Zealand:

  • Green Bay WWTP Dunedin, 3 iTURBO®-Blowers commissioned 2024
  • Shotover WWTP Queenstown, 3 iTURBO®-Blowers commissioned 2025
Conclusion

The Rotorua WWTP project highlights the capability of INVENT’s iTURBO®-Blower to deliver tangible improvements in energy efficiency, operational reliability, and process control in modern wastewater treatment. We are proud to contribute to the long-term sustainability of municipal infrastructure in New Zealand.

Download the iTURBO®-Blower brochure now!