King County Executive Dow Constantine joined local dairy farmers in Enumclaw to celebrate the beginning of construction on a digester project that will transform cow manure into green energy and other valuable resources.

“The robust agriculture industry on the Enumclaw Plateau is the perfect place for this innovation that will generate renewable energy, save money for family farmers, and preserve the environment,” said Executive Constantine.

Rainier Biogas LLC, a partnership between Skagit County-based company Farm Power Northwest, and at least three local dairies near Enumclaw, will build and operate the digester. The digester is an air-tight tank that uses microorganisms to break down or “digest” the manure and organic matter. The bacteria produce waste gas that can be harnessed to make electricity. Construction on the $4 million project is scheduled to be completed in summer 2012.

Manure waste management on dairy farms is a significant operational challenge for farmers because of its volume and handling expense. Improperly managed manure can pollute water bodies.

Processing manure over three weeks in a 1-million-gallon digester vessel, Rainier Biogas will generate enough electricity to power 600 typical homes.

The elimination of manure lagoon methane emissions combined with clean electricity will reduce net greenhouse gas emissions by the equivalent of 9,000 tons of CO2 per year, which is the equivalent of removing 2,200 cars from the road.

In addition, the treatment process separates digested straw from the processed manure, creating a source of cow bedding as well as a soil amendment to nourish fields that grow feed, saving farmers thousands of dollars a month in operational expenses.

Employees with King County’s Water and Land Resources and Wastewater Treatment divisions served as technical advisors related to agricultural sustainability and resource recovery, though the majority of the $492,000 King County has committed to the project came from federal grants appropriated by   Senator Maria Cantwell and Representative Dave Reichert.

The groundbreaking celebration was also attended by Washington State Director of the USDA’s Office of Rural Development, Mario Villanueva; representatives from Puget Sound Energy, One Pacific Coast Bank, Washington State University and the Andgar Corporation.