OREANDA-NEWS. October 2, 2012. GE (NYSE: GE) has installed a new aeration control system at the Bird Island Wastewater Treatment Plant in Buffalo, N.Y., that is projected to save the city more than USD350,000 a year in energy costs.

GE delivered a Roots Aeration Control System for the plant’s 32 aeration basins, replacing an older system. The new system has significantly improved the stability of the plant’s aeration process and also is capable of handling fluctuations in loading, which has allowed the plant to operate some of its aeration basins at dissolved oxygen (DO) set points well below the norm. This is providing additional energy savings.

“The system offers a logical approach that makes decisions like a plant operator would when controlling DO levels in the activated sludge basin,” said James Keller, treatment plant superintendent for the Buffalo Sewer Authority at Bird Island.

The New York State Energy Research and Development Authority (NYSERDA) completed a measurement and verification review of the Bird Island plant at the end of February. This review showed higher than expected energy savings, with projected annual savings of USD357,000.

“NYSERDA and National Grid both found the system attractive and offered incentives to fund the project,” said Keller. “The system will pay for itself in about 14 months and from there the savings will continue. This was a real win for the plant and the city residents.”

The Roots control system supplied by GE features a flow-based strategy where each individual DO probe is used to calculate the air requirement for each control zone. As data is collected, the system calculates the total air flow requirement for all of the 32 zones, and the change in air flow requirement is communicated to the blower control panel. The “DO-to-flow” concept also enables the use of “true” most-open-valve logic, where at least one valve is in the fully open position at all times. This reduces the system header pressure, which in turn reduces the load on the blowers and reduces the amount of energy needed to move the required amount of air.

“The GE system is based on a control algorithm specifically designed for the wastewater aeration process. Our main focus is to deliver a cost-effective system that provides a stable, reliable and energy efficient way to deliver the required amount of process air, while keeping the system intuitive and user friendly,” said John Parrish, North American sales leader, Roots blowers, compressors and controls—GE Measurement & Control for GE Oil & Gas.