Bellevue Pump Station upgrade

Completed – January 2011

The Bellevue pump station upgrade and force main installation was completed in two phases.

During phase one of the upgrade, a new 5,300-foot-long, 24- inch-diameter pipeline was installed from the Bellevue Pump Station directly to the Eastside Interceptor, a large regional pipe near Interstate 405. The force main project was completed in March 2008.

Phase two began in fall 2008. The above grade pump station was demolished and replaced with a facility featuring more powerful pumps, a new generator building, stronger odor control equipment and updated architecture. Completed fall 2010, the refurbished pump station is able to convey more than 13 million gallons of wastewater daily from west and central Bellevue to King County's South Treatment Plant in Renton—a 60 percent increase in capacity.

Pump station – completed Fall 2010

The refurbished pump station features more powerful pumps, a new generator building, stronger odor control equipment and updated architecture. The pump station is able to convey more than 13 million gallons of wastewater daily from west and central Bellevue to King County's South Treatment Plant in Renton.

Wastewater force main installation – completed March 2008

To protect public health and the environment, King County built a new wastewater force main to connect the Bellevue Pump Station to a regional pipeline east of I-405 that transports wastewater to King County's wastewater treatment plant in Renton.

The new 5,300-foot force main will help meet the wastewater treatment needs in west Bellevue and Bellevue's central business district for the next 50 years.

Work schedule

The project began in late July 2007 and finished in March 2008. Construction occurred in the following sequence:

Summer 2007

Crews staged equipment and supplies along Southeast Sixth Street in front of the Bellevue Pump Station and just east of the Bellevue Club. Drilling begins at both sites, proceeding east from the Bellevue Pump Station and west from the Bellevue Club. Equipment and supplies stored at the 118th Avenue Southeast and Southeast 5th Street intersection, north of the Lake Hills Connector work site.

Fall 2007

Drilling finished at Bellevue Pump Station and begins at Lake Hills Click on image to view in larger format

Winter 2007–2008

Drilling finished at Lake Hills Connector site. Pipe testing, repaving and restoration work began in early 2008. The project concludes in March 2008.

Horizontal directional drilling

To minimize community impacts and protect public safety, King County's contractor used an innovative technique called horizontal directional drilling to install most of the new pipe. Drilling rigs located at opposite ends of the pipe alignment used radio-guided drill heads to bore a pilot hole toward each other. The pilot hole has completed underground and widened by reaming tools to accommodate the sewer pipe. This type of drilling reduced the risk to property and the need for traffic detours, excavation, and repaving.

Drill sites

• Southeast Sixth Street, west of 102nd Avenue Southeast in front of the Bellevue Pump Station.
• Southeast Sixth Street between 112th and 114th avenues southeast, east of the Bellevue Club. The western drill route beginning at the Bellevue Pump Station ends here and the eastern drill route terminating at the Lake Hills Connector starts here.
• Westbound lane of the Lake Hills Connector near the Wilburton Trestle.

Oct. 2009. The old pump station (left) prior to demolition, temporary pump facility (on trailer), and foundation for new generator building.

View more photos on our Flickr site.