Sewer Bug Stories
At the Crossroads: Biosolids Management for Island County
Oak Harbor operates two wastewater treatment plants but we aren't complaining. For years Oak Harbor has depended on the Navy Seaplane Lagoon to store solids and provide capacity to their growing community by diverting the excess flow and all digested sludge there from the cities 0.7 million gallons per day (mgd) RBC plant. The problem Oak Harbor faces now is that their aging RBC facility located in Windjammer Park is reaching its life expectancy and the Lagoon doesn't have the capacity to treat future wastewater flows generated by both the City and Navy.
In 2005 Oak Harbor installed a covered "anaerobic cell" at the Lagoon and in 2008 upgraded the headworks to included perforated screening and vortex grit removal. This anaerobic cell and improved headworks has turn out to be a huge success with anaerobic cell effluent TSS of less than 50 milligrams per liter (mg/L). Lagoon chemistry and performance has been exemplary with very little buildup of sludge, in fact, no biosolids have been removed since 2005 and its anticipated none will for 7 to 8 years. Oak Harbor is at the crossroads, they now need to incorporate solids handling into a new 2 to 6 mgd MBR or Activated Sludge facility that is just now entering the facility planning stage. This would jeopardize the current solids handling method Oak Harbor has enjoyed at the Lagoon. Further difficulties with the Lagoon option arose when the Skagit River System Cooperative completed tidal flooding of the surrounding 300 acres to create a saltwater marsh habitat for Skagit river salmon to occupy in their early life stages.
"Oak Harbor operates two wastewater treatment plants but we aren't complaining."
Oak Harbor felt it needed to take the lead on a possible regional solution to biosolids management especially in the wake of new regulatory and process upgrades expected when building a new facility. Oak Harbor hosted a discussion exploring a regional solution to biosolids management. The gathering was well attended and nearly all invitees attended including Marietta Sharp Regional Biosolids Coordinator for Washington State Department of Ecology. The consensus reached at the first meeting was to strive for a Class "A" biosolid by means of a composting facility. This facility would be large enough to grow and meet the needs of Island County well into the future.
The facility would be owned and operated by a consortium of participating stakeholders in the region. Some participants felt the Navy should contribute land to the project and others thought the responsibility should fall on Island County. Oak Harbor will include solids handling options in their facility plan and will remain open to a regional solution. The city of Langley has a successful but undersized composting facility and would only desire a regional plant for backup. The Navy built a new containerized composting plant near the Ault Field Base and Anacortes incinerates their biosolids.
Most of the smaller communities are in need of help and are eager to participate but funding is an issue. As Oak Harbor works through its facility plan and the best methods are evaluated for biosolids utilization we'll revisit the participants for feedback on a regional solution. The kick-off meeting gave us all awareness to the diverse needs but the common desire to make this work for both Island County and Puget Sound, this areas lifeblood.