Anacortes gets first formal look at options to replace biosolids incinerator; consultant estimates $4.6M runway before stricter air rules apply

Brown and Caldwell consultant Greg Makos delivered a detailed briefing to the Anacortes City Council on March 23 on alternatives to the city's long-running biosolids incinerator, laying out a planning process, screening criteria and wide planning-level cost ranges that council members said they will track closely.

The presentation, introduced by wastewater plant manager Brian Walker, described a multi-step evaluation that will produce up to six "end-to-end" alternatives (from solids pickup through final disposition), run each alternative through a solids, water and energy evaluation tool, and then use a multi-criteria decision analysis workshop to weigh environmental, social, technical, regulatory and financial factors.

"We estimate that you have about another $4,600,000 that you can spend on the incinerator before triggering the 50% rule," Makos said of a regulatory test that could force an incinerator upgrade to modern (Quad L) air pollution controls. He described that $4.6 million figure as a conservative planning number based on the city's maintenance records and stressed that the number is a runway, not a guarantee of service life.

Makos offered planning-level cost ranges (not precise budgets) for potential near-term repairs, a solids bypass option (roughly $180,000'$730,000), and a full Quad L upgrade that he estimated at about $8.4 million at planning-level precision ("minus 50% plus 100%" uncertainty). He cautioned that the Quad L estimate does not include separate multi-year maintenance items identified in other planning ranges and that all figures are intentionally wide at this stage.

Council members pressed on site fit, lead times and combinations of technologies. Makos said some alternatives could be combined (for example, thermal hydrolysis with anaerobic digestion), while others are more likely to be stand-alone. He also emphasized the team's goal to remain technology-agnostic and avoid proprietary systems that could leave the city dependent on a single supplier.

The consultant highlighted regulatory and market issues the city will need to consider, including PFAS monitoring requirements the state is phasing in and the distinction between Class A and Class B biosolids disposal outlets. "There is a class A market out there," he said, adding that achieving Class A product quality often requires outreach and market building.

Next steps include an online survey for council and staff to confirm mandatory goals and evaluation criteria, followed by a public workshop and an MCDA session later in the year. Makos said the project schedule calls for a preferred alternative by the end of the process and that the consultant team will return with the six developed alternatives and a permitting matrix once the council and staff finalize criteria.

Mayor Walters and several council members said the issue will require sustained public engagement and a project web page to ensure transparency. The council will continue to receive updates as the team narrows alternatives, develops preliminary design estimates and documents likely permitting requirements and timelines.

The council did not take a decision at the meeting; the presentation set the process and asked the council to provide input through the forthcoming survey and workshops.