Biorefining Magazine has a profile on the Qualco Energy project, a partnership among Sno/Sky Agricultural Alliance, Northwest Chinook Recovery and the Tulalip Tribes:

Located in Washington’s Tualco Valley, the Qualco Energy Corp. anaerobic digester project in Snohomish County has come a long way since the idea of the project was conceived in 2003. At the Pacific West Biomass Conference & Trade Show held in Seattle, attendees got the opportunity to see the fruits of its labor up close and personal.

Qualco Energy, a nonprofit organization formed jointly by representatives from the Sno/Sky Agricultural Alliance, Northwest Chinook Recovery and the Tulalip Tribes, officially began operation of the digester in 2008. The digester was first proposed to help consume waste from local dairy operations and to prevent runoff into local salmon streams on land that formerly housed a correctional facility, which closed in 2002 after 60 years of operation.

According to Daryl Williams, environmental liaison for the Tulalip Tribes, Qualco Energy uses a modified mixed plug flow mesophyllic digester capable of producing 600 cubic feet-per-minute of biogas that powers its 450-kilowatt generator. Manure is collected from 1,400 cattle at Werkhoven Dairy’s three dairy farms and piped to Qualco’s 2 million gallon digester tank. Although manure is its primary feedstock, Williams said the digester can also take in expired beer and soda, but the digester is currently utilizing waste trap grease as feedstock.

“We’re producing a lot more gas than I thought we would before we built the facility,” Williams said. “Now that we’re using more [feedstock] in the digester I think it’s paying for itself.”