Leachate Pump Station Upgrades at Cedar Hills Regional Landfill

King County Solid Waste Department (KCSWD) operates leachate pump stations that serve closed landfill areas at Cedar Hills Regional Landfill (CHRLF). Several of the pump stations have been in service for approximately 30-years. While some updates have been made to the facilities since they were installed, additional modifications were identified to optimize pump capacities and ensure the continued safe operation of the pump stations. Herrera is responsible for the repair/improvement designs at Pump Stations 2 and 3, and conducted a conditions assessment, alternatives analysis, and design for retrofit of the pump stations. The project design was performed in 2020, including preparation of plans, specifications, and cost estimates.

Herrera is currently supporting KCSWD with contract negotiations during bidding. Construction is planned for 2021 and Herrera will support with RFI response, submittal review, and change order assistance as needed. Herrera is also supporting KCSWD with an extended flow monitoring program, which the conditions assessment phase identified a need for. Herrera assisted with development of a work plan and installation, troubleshooting, and maintenance of flow monitoring equipment. Herrera is currently conducting monthly site visits to download data and providing QA/QC on the data.