Failed backup generator led to raw sewage spill at Occoquan River

Water authority officials in Prince William County say a failed backup generator led to a sewage spill at the Occoquan River.

After an exclusive investigation, Potomac Local News has learned a tree limb fell onto a power line on Friday, April 3, knocking out power to a sewage pumping station at 13221 Marina Way in the Belmont Bay section of Woodbridge, according to Dominion Energy spokeswoman Peggy Fox.

That pumping station, or lift station, as it’s called, is located next to the Occoquan River and is operated by the Prince William County Service Authority. Power to the station was out for about an hour, according to Fox.

During the outage, a back-up generator at the sewage station failed to kick on. Subsequently, raw sewage — about enough to fill the size of a standard living room inside a house— began seeping up through a manhole cover, said Service Authority spokesman Keenan Howell.

Following the release of the raw sewage, the Service Authority posted a message to its website and social media accounts notifying residents of the incident. Some of the sewage could have seeped into the river, though Howell said it’s impossible to say how much.

A graphic posted to the website on April 3 showing a portion of the river that could have been affected, between the pumping station and the George Mason University Potomac Science Center, about a mile away, has been removed from the site.

Service Authority crews arrived on the scene of the spill within 25 minutes learning about it and started working to contain the mess. The Virginia Department of Environmental Quality was also notified of the spill, added Howell.

When the power went out, a power transfer switch on the station’s backup generator, designed to kick on in the event of a power outage, failed to do so. That triggered an alarm inside of the Service Authority’s headquarters notifying the agency that something was wrong, said Service Authority Deputy General Manager for Planning and Program Management Don Pannell.

Pannell called the transfer-switch failure a “rare situation.” Now, the Service Authority is looking at adding devices called phase monitors to all backup generators at its 63 lift stations across the county. Up until now, not every back-up generator has needed such a switch, added Pannell.

Environmental groups like the Prince William Conservation Alliance closely monitor the area’s waterways and often participate in annual waterway cleanups.

“This situation is clear evidence that Prince William County needs to pay more attention to its infrastructure, and the need to upgrade its infrastructure,” said Kim Hosen, executive director of the Alliance.

Each week, the Service Authority sends a test signal to each of its backup generators as part of a regular maintenance process, said Pannell. If the generator doesn’t respond, a technician is sent to the station to examine and report the backup equipment.

Each backup generator is inspected twice a year. The failed generator was last inspected in February, said Pannell.