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caption: A discarded mask is shown on Friday, November 20, 2020, along 7th Avenue South in Seattle's International District. 
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A discarded mask is shown on Friday, November 20, 2020, along 7th Avenue South in Seattle's International District.
Credit: KUOW Photo/Megan Farmer

Pandemic waste is adding to wastewater woes and Puget Sound pollution

A complicated series of events has led to where we are now — from the pandemic to pollution.

When the pandemic first hit in early 2020, people stocked up on face masks and gloves. And then people tossed those masks and gloves on the ground. And eventually, it all ended up in our sewage lines.

That also means these discarded masks and gloves are potentially now floating in Lake Washington, Lake Union, or Puget Sound and interacting with wildlife. It also means they are adding to environmental problems down the line.

There's no strict measurement to show how much pandemic waste is ending up in the environment. But there is anecdotal evidence — and it has certainly been noticed at King County's wastewater treatment facilities.

"Since the pandemic started, our plant operators have had to remove trash that included disposable, surgical type masks and gloves," said Marie Fiore, with King County's Wastewater Treatment Division. "This trash is removed both mechanically and by hand."

Trash in the wastewater system is not new. Fiore says it is a "persistent problem" — one that has more recently added face masks and gloves to the mix. Usually, it's material like paper towels and other wipes that are not supposed to be flushed. Feminine products and condoms are also common. It all tends to build up at chokepoints in the sewage system, prompting crews to unclog pipes at treatment facilities.

And recently, masks and gloves have become part of the trash mix flowing through Seattle area sewage lines, Fiore said. And that's a problem.

"Trash in the wastewater system is dangerous because it can clog pumps and pipes and disrupt conveyance," she added. "When the system gets compromised, the risk of a sewer overflow increases."

The trash collected from sewage pipes gets rerouted to a landfill.

caption: A small portion of the trash crews remove from the Seattle area wastewater system every day. 
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Fortunately, not all masks and gloves are making their way to a wastewater treatment facility, thanks to Seattle's sewer system that is more than 100 years old.

Seattle has a combined sewer system that was designed when city was far less populated. In short, the sewage from a building and rainwater from the street eventually meet in the same pipes and are sent to a treatment facility. From there, the waste is cleaned and flows into Puget Sound.

At least, that is the ideal scenario. There is something, however, that can throw that plan off and send raw sewage — including gloves, masks, and trash — into area waters. That "something" is rain.

The Seattle area's 100-year-old wastewater pipes cannot always handle all the water from heavy rains. When this happens, the system uses a series of overflows.

When too much rain overwhelms the pipes, the overflows send a mix of untreated stormwater and raw sewage into the nearest body of water — usually Lake Union, the canals, Lake Washington, and Puget Sound.

And now that masks and gloves are getting into the mix, they can potentially overflow out of the pipes, too.

"While some of the masks and gloves may be getting flushed down the toilet, we suspect the masks and gloves are making their way into the system through the storm drains after being littered on the ground," Fiore said. "Litter from sidewalks, streets and parking lots gets washed down the storm drains when it rains.

"Within the King County separated sewer system, our larger service area outside of Seattle, storm drains flow to our regional water bodies untreated," Fiore added. "Trash and pollution that enter the storm drains may flow to area waters and beaches."

The lesson: Trash belongs in the trash — not in the toilet or on the street.

Reports of wild animals getting tangled in face masks have spread across social media. KUOW checked with local wildlife rescue organizations and they do not report any incidents of pandemic waste interacting with local wildlife in this way.

It's not just Seattle

Pandemic waste is also causing problems across Puget Sound in Kitsap County. With a slightly different system there, crews are dealing with a slightly different issue.

“We're having [a problem with] what people are flushing," said Lisa Edge, education outreach coordinator with Kitsap County Public Works. "Whether it's just people are at home so much, or they're using alternatives to toilet paper which they should not be using … we have had issues with wet wipes, and the disinfecting wipes as well."

From paper towels to disinfecting wipes, people seem to be sending a lot more of these fibrous materials into sewage lines, where they do not break down but rather build up.

Kitsap's wastewater system is not like Seattle's. Stormwater flows into retention ponds that filter it out. So far, officials have not noticed a significant amount of masks or gloves showing up there.

Sewage goes through a system of 60 pump stations throughout the region en route to treatment plants, where officials have noticed all that non-flushable waste. Since March, public works crews have been dispatched to clogged pump stations multiple times a week to deal with the issue.

"It gets stuck along the way ... most of these non-flushables end up at our pump stations," Edge said.

"If we're not on on top of it, then we can have a backup, and we can have a sewer spill there. We're just asking the public to change their behaviors to help us prevent sewer spills. And not to mention, you know, it's not good if your pipes get clogged on your property either."

On top of that, another problem that Edge says has been exacerbated since the pandemic began is that more cooking oil and grease is showing up in the system. The assumption is that people are cooking at home more often now, and are pouring the grease down the drain.

In short: No cooking oil down the drain; and only toilet paper down the toilet. Even if a package of wet wipes claims to be flushable, it may not be.