An environmental study has been released detailing several ways King County could handle its trash in coming years and lays out options ranging from a waste-to-energy power plant to expanding the current landfill. The environmental impact statement (EIS) will provide the first major update to the county Solid Waste Division’s management plan since 2001, and deals with a range of issues including recycling levels and whether the county should build a waste-to-energy (WTE) plant. The King County Council is scheduled to select its preferred alternatives early next year — decisions that will have widespread and prominent effects.
The most critical decision will be how the county deals with trash. King County has one remaining landfill located near Maple Valley. The Cedar Hills Regional Landfill is currently building its eighth and final cell, which will be filled until it reaches a maximum height of 800 feet above sea level in 2028. Once that happens, the EIS lays out five alternatives. The first would be to emulate what the city of Seattle does in its contract with Waste Management, where all solid waste is packed onto train cars and shipped to another landfill, likely in eastern Washington, Oregon or Idaho.
This option assumes the landfill will hit capacity as expected and the county would then contract with BNSF or Union Pacific to handle the 1.3 million tons of waste it generates annually. This would account for around 2 percent of all freight traffic in the state and run around $5 million to $7 million in capital costs. However, a 2014 study from the Washington State Department of Transportation shows some parts of the rail system could be over capacity. While trash from King County would account for around 2 percent of all freight, King County Councilmember Kathy Lambert has said in previous stories that she is worried hauling trash will be low on the list of priorities for railroads.
The second option would further develop the Cedar Hills landfill and begin shipping waste to another landfill when it reaches its new limit. The landfill height could potentially be increased to 830 feet in some places, extending its life until 2040. This would cost the county between $240 million to $270 million in capital expenses.
A third option, and one which Lambert has been advocating for, is to build a waste-to-energy power plant and use the landfill to deposit residual solid waste and ash. This leftover waste could also be shipped by rail to other landfills. The EIS finally puts some figures on this option, saying it would create around 2,000 metric tons of carbon dioxide (CO2) annually over a 50-year lifespan, slightly less than .01 percent of the total current greenhouse gas emissions in King County.
The final two options involve using aerobic or anaerobic digestion processes to create methane, which can be siphoned off and refined by Bio Energy Washington, which already has a facility at the landfill. The difference between the final two options is whether processing would be done off-site by a private company or at the county’s landfill.