Planning Commission approves rehabilitation of Holmes Run Wastewater Pump Station

The entrance to the Holmes Run Wastewater Pump Station at 6623 Dearborn Drive.

The Fairfax County Planning Commission approved plans on May 19 to rehabilitate the wastewater pump station at the corner of Dearborn Drive and Sleepy Hollow Road.

Built in 1957, it’s one of the oldest pump stations in Fairfax County. The improvements will allow it to operate at a high level for the next 30 years, said Julie Strandlie, the Mason District representative on the Planning Commission.

The pump station as seen from Sleepy Hollow Road.

The interior improvements include replacement of the pump and discharge pipes and upgrades of the instrumentation and control system.

Exterior improvements include a new fluid injection system for enhanced odor control in the Holmes Run and Tripps Run sewer lines, a new emergency generator, an improved equipment loading system, a force main bypass pumping connection, improved site access, replacement of gravity sewer components, and replacement of force main sections.

A rendering of the pump station after rehabilitation. [Arcadis]

A new eight-foot fence will be built around the facility, and a brick screening wall will surround the generator and other equipment.

The wastewater pump station serves a population of approximately 35,000 within a 6.8-square mile area extending to the west and north of the pump station to Arlington Boulevard, the beltway, and I-66.

Related story: Fairfax County to rehabilitate wastewater pump station in Mason District

The station diverts a portion of the wastewater flow from the 33-inch Holmes Run gravity trunk sewer, which is just south of the pump station. Wastewater collected in the station is subsequently pumped via a 20-inch force main pressure sewer to gravity sewer manhole #113, located approximately 2,000 feet
north of the pump station on Sleepy Hollow Road.

From there, the wastewater enters the Tripps Run gravity sanitary sewer and is combined with the Holmes Run gravity trunk sewer below Lake Barcroft. The wastewater is eventually treated at Fairfax County’s wastewater treatment plant in Lorton.

The rear of the pump station.

During construction, wastewater will be bypassed through a temporary pumping system.

When the project was announced last July, county officials said construction would start in spring 2021, so it’s already several months behind schedule.