By Lindsay Peyton

A barge parked on the Lower Duwamish Waterway on Tuesday morning, Dec. 20, was on a special mission.

On board, an employee of environmental engineering firm Dalton, Olmsted & Fuglevand, scooped up buckets of sediment mixed with activated carbon and carefully deposited the mixture in strategically mapped spots on a chart of the waterway.

The effort marked the first step of an innovative pilot study – designed and funded by the Lower Duwamish Working Group, a collaborative effort between King County, the City of Seattle, the Port of Seattle and the Environmental Protection Agency (EPA).

Jennifer Kauffman, project manager for King County, explained that the activated carbon is meant to accelerate nature’s clean-up process.

The Lower Duwamish Working Group will run a side-by-side comparison of the effort with a control plot without activated carbon to test the material’s effectiveness.

“After three years of data collecting, we’ll be able to tell how good the technology is,” Kauffman said. “Activated carbon is used all over the U.S. and Europe, but the Duwamish is different. It’s a river, and it’s affected by tidal currents.”

She added that marine activities and the use of the waterway as a navigation channel could also impact the study.

Kauffman said that the EPA has approved an extensive plan to address the large variety of contaminants in the river.

The agency added the Duwamish to its Superfund National Priorities list in 2001. The waterway’s pollution levels have soared as a result of industrial activity and run-off from surrounding residential areas.

“We have a proposed plan with various technologies in various places,” Kauffman said. “We have things we can do – but can we do it better, with better results? That’s what this is all about. This could be another tool in our environmental tool box.”

Monica Van der Vieren, a spokeswoman from King County’s wastewater treatment division, explained that activated carbon is the same technology used in some household water filters.

She said that the information gathered in the Lower Duwamish Working Group’s study could guide future environmental clean-up efforts.

“We’re trying to take early action,” she said. “We’re working together to do as much as we can, as fast as we can, and whatever comes out of this will inform other projects.”

Van der Vieren said the first data collection will be in 2018 – and outcomes will be posted online.

Elly Hale, remedial project manager with the EPA, said the clean-up plan for the Duwamish was issued in late 2014 and included both dredging the waterway and letting natural processes take their course.

“This clean-up plan also requires that we look at ways to accelerate, to speed up natural recovery,” she said. “We want to get to the finish line as soon as we can.”

Robb Webb, principal engineer for Dalton, Olmsted & Fuglevand, said that there will be a series of monitoring events held on the testing site over the next three years.

“The hope is to come up with ways that are better in the long-run,” he said. “This could be something less time-consuming, with less impact on residents and the waterway.”

For more information on the Lower Duwamish Waterway Group, visit www.ldwg.org.