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Roots® Connersville

Based in Buffalo in New York State, Bird Island is one of the largest treatment plants in the Northeast.

Optimization of dissolved oxygen control system.

In 2011, Roots began operating the largest‑ever installation of its Roots IntelliView controls system at Bird Island’s aeration basins — a complex  aeration blower application that required precise process air control to meet efficiency and performance objectives.

Bird Island Wastewater Treatment Plant (WWTP) in Buffalo, New York, had an inefficient aeration control system which, ironically, had been installed in 1998 as an efficiency upgrade.

Challenge

The operating principle was that air flow to all 32 of the plant’s aeration basins, or zones, would be properly controlled by an average of several Dissolved Oxygen (DO) level measurements taken by DO probes in a few of the basins. However, changes in tank loadings and physicadynamics, along with differences in oxygen transfer rates between diffuser grids, prevented a uniform air flow in the aeration zones. The plant also struggled to accurately adjust the air flow from the blowers because the 60 second open/close travel time of the valve actuators was too short.

 

By 2008, the Buffalo Sewer Authority (BSA) decided it had to cut the energy consumption of the blowers, which used more energy than any other part of the plant. To make that happen, the plant would have to get a new system that independently controlled each aeration basin. Bird Island, the second largest wastewater treatment facility in New York State, with a dry weather design flow of 180 million gallons per day (MGD), had obtained four 5,000 HP Roots single-stage compressors back in 1980, two of which had been rerated to 3,000HP in 1995, and after looking at product options for two years, BSA turned to Roots for another solution to Bird Island’s aeration control problems.

Response

Roots partnered with BSA to redesign the aeration control strategy and recommended replacing the existing valve actuators with RCS actuators featuring a 180‑second open/close travel time. In the fall of 2011, Roots commissioned the largest‑ever installation of its IntelliView Controls system at Bird Island. The solution — incorporating RCS actuators, a Roots Aeration Master Control Panel, and secure remote access — has since been deployed at more than 300 U.S. wastewater treatment plants.

 

The upgraded system was integrated with high‑capacity Roots blowers from the  RGS blower series, enabling the airflow modulation and pressure management required for large‑scale municipal aeration.

 

At the core of the solution is a flow‑based control strategy in which individual DO probes calculate airflow demand for each basin. These demands are aggregated to determine total system airflow, with corresponding adjustments communicated to the blower control panel. A key component of this “DO‑to‑Flow” methodology is the use of true Most‑Open‑Valve logic, ensuring at least one valve is always fully open. This reduces system header pressure, lowers blower load, and significantly cuts overall energy consumption.

 

BSA applied to the New York State Energy Research and Development Authority (NYSERDA) for partial funding to defray the estimated $800,000 project cost. BSA documented an expected annual savings of 3.8 million kWh equaling $345,000. This would be accomplished by lowering average DO levels from 3.1 milligrams per liter (mg/L) to 1.5 mg/L. NYSERDA was willing to pay for up to 50 percent of the project, and conducted a measurement and verifi cation review to test those assumptions.

ROT-En-Product-Document-aeration-control-system-at-bird-island1

Outcome

The project delivered a highly reliable and efficient ventilation‑on‑demand system that reduced energy costs while maintaining process stability. Roots IntelliView controls greatly improved the consistency of aeration performance and enabled the plant to operate at lower DO setpoints — as low as 0.75 mg/L in the first pass — without compromising treatment effectiveness. The result was additional energy savings and tighter control over process variability.

 

NYSERDA’s post‑project review confirmed that annual energy savings exceeded initial estimates, ultimately providing BSA with funding assistance covering half the total project cost and delivering a rapid return on investment. For facilities looking to implement similar efficiency‑driven upgrades, learning how to choose the right blower for your application is a critical next step in achieving long‑term performance and energy savings.