Duvall Landfill – Landfill Gas Control & Cover System Improvements
King County Green Bonds
The 13-acre landfill closed in 1981 with clay and tree cover, a passive leachate collection system around the perimeter, and a flared, passive gas (no vacuum) monitoring system. No bottom liner. Groundwater treatment, groundwater and landfill gas monitoring, and a poplar tree landfill cover are all in place. An emergency radio tower is located on the property.
- Reduce low-level groundwater contaminants in an area where refuse is prone to saturation;
- Improve the grass and tree cover to reduce water infiltration and improve carbon sequestration;
- Evaluate wastewater control system improvements to improve groundwater quality;
- Installation of a gas collection and control system to reduce greenhouse gas emissions completed by 2026;
- Conclude improvements and provide property for secondary beneficial use.
Key environmental attributes
- Groundwater quality improvements to meet regulatory compliance that are protective of human health and the environment, through installation and improvements to the environmental control systems;
- Reduce the potency of GHG emissions to the greatest extent feasible, through the collection and treatment of landfill gases;
- Achieving the above goals in order to minimize or terminate post-closure activities.
Green Bonds: 2017-Series A
$0.8m Green Bond Proceeds spent
In progress GHG emissions MTCO2e/yr
In progress water quality metrics