EPA alleges Lynnwood sewage plant violated Clean Air Act; city faces second fine in a year 

For the second time in under a year, Lynnwood faces a fine from the Environmental Protection Agency for federal violations at its wastewater treatment plant– this time for alleged violations of the Clean Water Act, according to a settlement notice posted Tuesday. 

The EPA seeks $4,350 from Lynnwood, stating the water coming from the plant has more pollutants in it than allowed by federal law. The plant also failed to submit a number of permits and reports on time.

The city has 10 days to pay the fine, according to the settlement agreement. Mayor Christine Frizzell has signed the settlement, Lynnwood spokesperson Nathan MacDonald said in an email. 

The EPA alleges Lynnwood “failed to submit timely permit and compliance schedule reports, and failed to meet effluent limits for total suspended solids and carbonaceous biological oxygen demand as required by their National Pollutant Discharge Elimination System permit.” 

This means water emitted from the sewage treatment plant contained amounts of suspended solids – or fine particulate matter – exceeding federally approved limits. 

The EPA also found that the water coming from the plant contained too much carbonaceous material, such as graphene or activated carbon. These materials can be used to remove pollutants from water, according to a study published in the Multidisciplinary Digital Publishing Institute. 

The plant had nine of the aforementioned violations in the past year. One such incident occurred in April, when the plant reported a total suspended solids value of 61.6 mg/L  The limit is 45 mg/L. In December, the plant’s suspended solids value was 135.5 mg/L. 

But there’s been an upside to the setbacks, MacDonald said. As a team, city staff have figured out ways to avoid these issues in the future and run the plant in a more efficient manner.  

These changes have “allowed us to clean the wastewater at levels we have not seen in some time based on the parameters we are to monitor based on our permit from Ecology,” MacDonald wrote. 

“We have lowered our liquid sludge volumes to levels where rain events will not cause violations. We can sustain and recover from equipment failures much faster. We are more energy efficient with less sludge volume because we have been able to take off primary and secondary clarifiers plus an aeration basin. As a city, we are doing everything we can to ensure these violations are not a part of our future,” he said.

In November 2023, the EPA fined Lynnwood $550,000 after finding the plant’s sewage sludge incinerator emitted illegal amounts of particulate into the air. 

The city shut off the 60-year-old incinerator in late April, replacing it with a temporary system that ships the waste to a landfill in Oregon, Lynnwood Wastewater Plant Supervisor Tanner Boyle said in an interview. 

These fines come amid the city’s push to revamp the plant through the Lynnwood Wastewater Treatment Plant Facility Plan – projected to cost over $200 million with estimated completion in the early 2030s. 

MacDonald said some of the violations, specifically the late permits, happened under old management.

“The late permit submittals were done under past management and are unable to be explained without their reasoning,” MacDonald said in an email. “The team has created a system with safety checks and redundancy so that permit submittals will not be an issue in the future.” 

Last year’s issues with the sewage sludge incinerator and several large storms were behind some of the violations, he said. 

In December 2023, the incinerator’s ability to handle solids was “already at it’s low end,” MacDonald said, coupled with high volumes of solids coming to the plant. At times the incinerator would break down— requiring the plant to find a trucking company to haul to solids to other facilities. 

“The downtime would add extra solids to our system,” MacDonald wrote. “In conjunction with this issue, we had a very large rainstorm that put our flows over 20 million gallons a day (MGD) for some amount of time. For reference, the flow for the month averaged 5.56 MGD.”

The heightened flow can push fine solids right past the systems — or clarifiers — meant to filter them out and into the treated water.

The incinerator broke down again in April, leading to a similar event. 

A power outage in February caused the plant’s generator to malfunction. This along with a large rain storm carried excess fine solids over the clarifiers and into treated water. 

The plant also exceeded legal solid matter limits in May when the incinerator was shut down and the plant switched to a new solids handling system. 

— By Ashley Nash