(September 13, 2018) - A combination of partially treated sewage and stormwater overflowed for about 20 minutes last night from the City’s wastewater treatment plant to the Columbia Slough.

The public is advised to avoid contact with the slough for 48 hours in the vicinity of North Portland Road where the overflow occurred.  Warning signs are posted in the area. Other parts of the slough are unaffected.

The cause was an automatic gate within the treatment plant that malfunctioned. The overflow occurred for about 20 minutes before the gate was repaired. The effluent received primary treatment, which removes solids and other contaminants, but it was not disinfected. The volume is unknown and this incident is being investigated further.

 The Columbia Boulevard Wastewater Treatment Plant is located at 5001 N Columbia Boulevard and operates 24 hours a day every day to manage and treat wastewater from Portland’s more than 600,000 residents and businesses. 

The Bureau of Environmental Services provides city residents with programs to protect water quality and public health, including wastewater collection and treatment, sewer construction and maintenance, stormwater management, and stream and watershed restoration. www.portlandoregon.gov/bes and @BESPortland.

Media contact: Diane Dulken (503)823-5328. diane.dulken@portlandoregon.gov