Global design firm Stantec led the engineering and architecture for the $40-million project for the King County Wastewater Treatment Division (WTD). The Sunset and Heathfield Pump Stations send sewage from Sammamish, Issaquah, and Bellevue to the WTD’s South Treatment Plant in Renton. For nearly 50 years, these stations served the area reliably but were reaching their operational limits. The project upgraded the pump stations and the connected force main pipe to ensure the WTD can continue serving a growing population for decades.
The upgrades allow the system to convey a peak capacity of 30 million gallons per day. The design included:
- The installation of four new higher-capacity vertical, extended shaft pumps at each pump station
- Associated electrical upgrades
- New facility roofs, including a green roof at Sunset Pump Station
- New variable refrigerant flow heating, ventilating, and air conditioning systems at both the Sunset and Heathfield Pump Stations
- A novel oxygen injection odor and corrosion control system at Heathfield Pump Station
Other key project elements include the installation of a new 24-inch force main pipe to replace an old 12-inch pipe, restoration of the Lake Sammamish shoreline below the Sunset Pump Station, habitat restoration at Heathfield Pump Station, and enhancement of wetland.
“Assisting King County Wastewater Treatment Division provide needed upgrades to its facilities while also focusing on sustainability is very satisfying,” said Mark Graham, Stantec Senior Principal and Project Manager in Bellevue. “Pump stations play a key role in wastewater management. To see these facilities also provide on-site stormwater management, a green roof, native plants, and more is a testament to the WTD’s goal for sustainability.”
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The sustainability achievements contributing to the award include:
- Protecting the natural world by restoring habitat, maintaining floodplain water quality, preserving undeveloped land, using only native vegetation, and removing invasive species.
- Involving stakeholders and responding to their needs by surveying more than 250 neighbors and community members during design so the project team could learn about their ideas and concerns. Community input is reflected in the final design.
- Implementing a sustainability management system by requesting manufacturers submit sustainability policies to ensure supply chain sustainability, requiring an internal sustainability scorecard, and developing an equity plan for the project.
- Improving public health and safety by enhancing the continued reliability of the sewage treatment system and installing a new technology that will reduce pipe corrosion and extend the life of odor control.
“This important infrastructure investment allows us to continue to serve our community, protecting public health and the environment,” said Kamuron Gurol, WTD Division Director. “We’re dedicated to developing a diverse workforce, committed to equitable and sustainable construction practices, and appreciate the recognition of our practices in this award.”
