In 2016, the wastewater aeration system was consuming approximately 50% of the total electricity at an Ohio WWTP. Knowing the Inovair direct-drive IM-30 integrally geared centrifugal blower provided the lowest total cost of ownership, even when compared to gearless high-speed turbo blowers the plant reached out to Inovair to apply Inovair’s technology to lower power costs and improve DO control. The existing blowers operated at a constant speed and used an inlet throttling valve to regulate flow. These blowers had been moved into a new blower building in 2010. However, the three (3) 100 HP existing blowers were difficult to control, very inefficient and had limited turndown. Because of the compact footprint of the Inovair blower and self-contained motor and the ability to use the existing electrical and discharge piping/components the Ohio plant was able to act as their own General Contractor to install the more efficient, reliable, and dynamically controlled Inovair Blowers.
The goal was to reduce the annual energy costs associated with the blowers as well as improve DO control which would increase process control while reducing power consumption further. The plant had three (3) constant speed 100 HP multi-stage centrifugal blowers two (2) blowers ran 24/7 during peak demand in the summer and one only (1) blower ran during the winter, delivering a maximum flow of 2750 SCFM during peak. The existing multistage centrifugal blowers had a rated design flow of 1375 SCFM each at a discharge pressure of 8.50 PSIG. These blowers utilized an inlet throttling valve to control the output flow. This limited blower control allowed the DO levels to fluctuate out of range as ambient conditions change.
Utilizing Inovair’s selection software it was determined the Inovair IM-30 integrally geared centrifugal blower could meet the design conditions with 75 HP per blower and upon installation, the plant could immediately reduce their blower’s power consumption by over 25%. The Inovair IM-30 blower turndown range gave the plant operational flexibility that was not previously possible; additionally, the onboard PLC which automatically controls the blowers’ airflow based on ambient conditions was able to tighten up the fluctuating DO levels in the aeration basins. This control ability resulted in less airflow with limited operator input thus contributing to the overall blower system efficiency and cost savings. Thanks to Inovair’s blowers’ energy efficiency and a dynamic control of airflow the power consumption went down by almost 350,000 kWh, reducing energy bills by over $26,000. Combining the low initial capital cost, installation costs, and energy savings the payback was substantially faster than would be possible with other blower technologies.
With thousands of reliable hours of operation and substantial documented energy savings with their aeration process blowers, the plant decided it was a no-brainer to use Inovair blowers when their digester blowers needed replaced in early 2020. With the knowledge that the Inovair blowers would reliably operate on a varying pressure digester application, coupled with the fact that the plant could perform the installation, the plant purchased three Inovair IO series blowers. The plant has not been disappointed with their decision. The blowers have performed flawlessly. They are comfortable knowing the Inovair blowers will provide efficient, reliable service for years to come.