Crews dump sewage at Metro Vancouver treatment plant after blockage found

The Iona Island Wastewater Treatment Plant is seen from above in this photo from Metro Vancouver's website. (metrovancouver.org)

Officials are investigating a blockage that forced a Metro Vancouver wastewater treatment plant to dump untreated sewage into the ocean as an emergency measure.

A spokesperson for the Metro Vancouver Regional District says the disruption at the Iona Wastewater Treatment Plant in Richmond was caused by “an unusual volume of rocky debris” that jammed screening equipment at the plant’s intake.

The treatment process was shut down at approximately 2:40 p.m. Thursday and crews were deployed to clear the blockage.

During the disruption, wastewater was diverted to a deep-sea outfall pipe that extends about seven kilometres into the Strait of Georgia, the spokesperson said.

The sewage discharge lasted for more than three hours before normal treatment operations resumed shortly after 6 p.m.

“Crews have made significant progress, with three of the plant’s six screens now fully repaired, which is what is needed for normal operations,” Metro Vancouver spokesperson Jillian Glover wrote in an email Friday.

“The cause of the disruption remains under investigation and will be reviewed further once all restoration work is complete.”

The district said preliminary modelling indicates no public health impacts are expected as a result of the sewage discharge, although routine beach water monitoring is continuing.

The incident comes weeks after workers at several Metro Vancouver wastewater treatment plants, including Iona, briefly walked off the job as part of a labour dispute between the district and the workers’ union.