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Energy-saving upgrades at the wastewater treatment plant in Bandon, Ore. could save the city more than $17,000 per year.
According to Bandon City Manager Matt Winkel, the city recently partnered with the Bonneville Power Administration, the Northwest Energy Efficiency Alliance and BacGen Technologies in a market transformation initiative to save energy in wastewater treatment plants.
Winkel said the wastewater treatment plant was one of the first to employ the innovative approach to conserving energy and saving money.
The city's sewer system serves approximately 1,425 customers. It is an activated sludge facility, with a design capacity of 1.5 million gallons per day and average influent flows between 500,000 and 900,000 gallons per day, Winkel explained.
The project included strategic placement of sensor units in the aeration and aerobic digester basins and dynamic modeling of the facility. The upgrades allowed the existing computer system to be programmed to control the blower motors and intake valves.
Energy savings were achieved by reducing the blower from 80%-20% speed averages, reducing a high-speed blower from high speed to low speed and shutting off one blower completely. An upgrade of the disinfection system also was included in the project.
The project cost about $83,000, which was shared between the city, BPA and the NEEA. The upgrades will result in a savings of 294,000 kilowatt hours per year, a 29% decrease. The savings could result in an operational cost reduction of $17,581 per year.
For additional savings, the city is investigating the feasibility of installing a cover on the sludge drying basins, which, if successful, would allow year-round sludge removal in Bandon's moist climate and save money by reducing aeration energy use.
Bandon's wastewater project has been included as the featured case study in a professional, peer-reviewed paper that describes BPA's Water and Wastewater program and related matters, Winkel said.