LACEY - About 10,800 gallons of raw sewage spilled at the LOTT Alliance treatment plant on Martin Way Wednesday when a valve was left open at a nearby pump station, sending too much flow to the plant.
The untreated wastewater flowed through the plant, down a driveway and into a stormwater treatment basin at the treatment plant at 6121 Martin Way. E., Lacey. City crews vacuumed the wastewater out of the basin, along with wash water used to clean up the mess.
Neither the public nor LOTT employees were exposed to the raw wastewater during the spill, said Lisa Dennis-Perez, LOTT Alliance spokeswoman.
The spill lasted for 17 minutes during maintenance work at the pump station. A valve was opened directing all the flow to the Martin Way plant about 10:15 a.m. Normally, only 50 percent to 65 percent of the flow goes to the Martin Way plant and the rest goes to the Budd Inlet treatment plant in Olympia, Dennis-Perez said.
The Martin Way plant is a satellite plant built by the Lacey, Olympia, Tumwater and Thurston County sewer partnership to treat wastewater so it can be reused.
To prevent a similar accident in the future, LOTT will re-label the valves at the pump station to clarify flow direction, LOTT officials said.
Operations and maintenance procedures for returning equipment to service after repair are under review.
The state Department of Ecology was notified of the incident, a move required by state law whenever there is a spill.
John Dodge: 360-754-5444