The city of Oak Harbor is about to bring Puget Sound’s newest wastewater treatment plant online. It’s designed to fit alongside a revitalized downtown park, service the community’s needs for many years, and contribute to continuing efforts to restore and protect water quality in the Sound.
Oak Harbor dedicated its new plant, located on the Whidbey Island city’s namesake inlet, today. We couldn’t be happier to be part of the celebration.
We’ve provided over $105 million dollars in financial assistance, through low interest loans and grants, for design and construction of the $128 million dollar project.
The plant will be able to treat up to 5 million gallons of wastewater per day. The city’s current daily volume is about 1.5 million gallons, serving about 22,300 people.
“I want to commend the city for its early and ongoing proactive community outreach and communication. The city went to great lengths to ensure that information was shared with its citizens from planning through construction,” said Jeff Nejedly, who oversees Ecology’s Water Quality grants and loans, at the ribbon-cutting event.
The new all-indoor plant replaces two outdated facilities. One was a smaller city-owned plant that was located near the new plant site. The other is a large wastewater lagoon plant located at Naval Air Station Whidbey – Seaplane Base.
Oak Harbor’s new system treats wastewater with membrane bioreactors, or “MBRs.” The advanced technology uses ultra-filtration membranes to remove solids left over after beneficial microbes digest the city’s sewage. The result is water that has had most of its impurities removed and residual solids that can be further processed for beneficial use as a fertilizer.
“This advanced wastewater treatment system is capable of producing high-quality “Class A” reclaimed water that can be used for irrigation in parks and in other public areas. This can reduce dependence on drinking water sources for activities that don’t require drinkable water,” said Nejedly.
The first planned use for the plant’s reclaimed water will be irrigation for the adjacent Windjammer Park, which the city is redeveloping in tandem with the treatment plant project. The city is in the process of finalizing a proposal to divert a portion of the water produced at the facility for these purposes.
The MBR technology is capable of producing water that contains lower levels of nutrients, such as nitrogen and phosphorus, than conventional wastewater treatment systems. Excess nitrogen can cause conditions that upset the Puget Sound food web. Maintaining healthy conditions promotes the recovery of salmon, which are the natural prey of Puget Sound’s southern resident orcas.
Oak Harbor’s work on the new plant dates back to 2010 and earlier, when city staff and elected officials determined that the city’s growth would exceed the existing treatment plants’ capacity. Staff from our Water Quality Program provided technical review and assistance on sizing and designing the new system, in addition to the financial assistance.