King County plans long-term waste disposal solutions as Cedar Hills landfill nears capacity

The City of Kent's Committee of the Whole and Workshop convened on June 17, 2025, to discuss critical long-term waste disposal options for King County, led by Tony Donati from the King County Solid Waste Division. The meeting focused on the impending closure of the Cedar Hills Regional Landfill, projected to reach capacity by 2040, and the need for alternative waste management strategies.

Donati introduced Brian Halverson and Chris Stubbs from the Solid Waste Division, who presented findings from a comprehensive long-term disposal study. The study aims to inform decision-making for waste management in King County and its partner cities, including Kent. The presentation outlined various disposal methods under consideration, emphasizing the urgency of planning for waste management beyond the landfill's closure.

The study evaluated five disposal options: waste export by rail, mass burn with waste export, gasification, pyrolysis, and refuse-derived fuel. However, only waste export by rail and mass burn with waste export were deemed feasible for future implementation. The study analyzed three different tonnage scenarios to account for potential variations in waste generation and composition from 2040 to 2060.

Key criteria for evaluating the disposal methods included economic impact, environmental impact, social impact, capacity, logistics, and operational history. The findings indicated that mass burn facilities, while capable of reducing waste volume significantly, pose challenges such as high capital and operational costs, potential environmental drawbacks, and public opposition to siting.

The meeting concluded with a commitment to further community engagement and input through the Metropolitan Solid Waste Advisory Committee. A final decision on the preferred disposal method is expected after the completion of an environmental impact statement scheduled for 2026. The discussions underscored the importance of proactive planning to ensure sustainable waste management solutions for King County's future.