Although the failure of Seattle’s West Point wastewater facility has dumped hundreds of millions of gallons of raw sewage into Puget Sound — and threatens to add more in any rainstorm in coming weeks — the upshot for Tacoma and the South Sound is largely indirect.
Despite the volume of dirty water coming into the sound, the distance and oceanic dilution between Seattle and Tacoma waters means health officials aren’t concerned about the discharge requiring beach closures in Pierce County, as have been done in King and Kitsap counties within a few miles of the broken plant.
How close the pollution might creep remains to be seen. State Department of Ecology officials won’t make their regular survey of Puget Sound until later in the month to look for any spreading trouble signs.
However, one aspect of the situation has attracted concern in the South Sound: the possibility such a disaster could happen here.
As in Seattle, Tacoma has many long-established neighborhoods served by old-style sewer systems in which stormwater and toilet water run through the same pipes. Because of that, a Tacoma version of the West Point failure of a pump during a heavy rain could cause a similar catastrophic failure requiring long, expensive repairs.
“I can’t tell you it would never happen,” said Michael P. Slevin III, Tacoma’s environmental services director. “I can say it’s my job to make sure it doesn’t happen. Don’t make me knock on wood.”
Tacoma has two wastewater treatment plants with similar setups to the West Point facility — the Tideflats central treatment plant and a smaller one on Ruston Way.
Each takes in only a fraction of the water of the West Point plant, so any similar breakdown here would foul less water, Slevin said.
Seattle’s West Point plant treats up to 450 million gallons of dirty water a day. Tacoma’s central plant maxes out at about a third of that, and the smaller one treats up to 30 million gallons.
The North End plant has run 17 years without shutdown issues, Slevin said. The central one shut down during a 2015 blackout and sustained “minor” internal flooding, he said.
A $100 million upgrade to the central facility, completed in 2011, has buttressed the system’s stability, Slevin said.
The Seattle facility was not unsound, he said.
“They just hit the perfect storm,” Slevin said. “I feel really bad. The people in Seattle are very professional, and they do a very good job.”
Although dilution should prevent widespread dire consequences from the West Point plant’s sewage dumping, he said there is good reason to remain concerned about it and other occurrences of untreated sewage going into the sound, such as the ongoing municipal practice of Victoria, British Columbia.
“For the long-term health of Puget Sound, having this much biological oxygen demand (created by the sewage) and this much different issues entering the sound, it affects the biosphere,” Slevin said.
The sewage dump could affect migrating salmon, which travel through the area of the spill, said Melissa Malott, executive director of Citizens for a Healthy Bay.
Salmon fry, she said, are vulnerable on their trips into ocean waters, because the transition to life in salt water is hard on their bodies even when it isn’t polluted.