The City of Vancouver, Washington, typically treats more than 20 million gallons of wastewater each day. This requires substantial aeration systems and ultraviolet (UV) light arrays at the city’s two wastewater treatment plants (WWTPs). While these systems are critical for supporting the biological treatment process and destroying harmful bacteria and pathogens, they consume large quantities of power.
“Through a series of workshops and a subsequent energy audit, we found that we could improve our energy ef ciency without impacting water quality,” says Dick. “We also learned that we could receive rebates for energy ef cient equipment and incentives for power reductions from Clark Public Utilities, so we jumped at the opportunity.”
These incentives and rebates are supported by the Bonneville Power Administration’s Energy Smart Industrial program, which works with Northwest public utilities and their industrial customers – offering project management, technical assistance and nancial incentives – to advance energy ef ciency throughout the Northwest. With the help of BPA’s ESI program and Clark Public Utilities, the City of Vancouver has made a series of energy improvements at its WWTPs.
All told, the improvements are saving the city roughly one million kilowatt-hours and tens of thousands of dollars per year. ESI support and utility incentives covered about 30 percent of the project’s capital costs. And more energy upgrades are on the horizon.
CAPITAL AND OPERATIONAL ENHANCEMENTS IMPROVE ENERGY EFFICIENCY
The multi-stage centrifugal blowers at Vancouver’s WWTPs were running just ne, but they were outdated and inef cient compared to newer airfoil turbo blowers. By replacing one of the four existing blowers at each plant with a new turbo unit, the city was able to realize signi cant energy savings and payback their initial investment in less than two years.
“We used to have two blowers constantly running at each facility,” explains Aaron Kraft,
Project Manager for Veolia Water North America, which operates the WWTPs for the
City of Vancouver. “Now we can get by with a single turbo blower at each treatment
plant most of the time.”