At new Marysville water treatment facility, plants filter out pollutants

MARYSVILLE — The city’s new stormwater treatment plant isn’t landmarked by large tanks and pipes — or any buildings for that matter.

Near the shore of Ebey Slough, the plant — charged with treating 460 acres of urban runoff — looks like a park, with paved walkways and rows of native grasses.

The facility at 1304 First St. in Marysville incorporates new filtering technology never before seen at this scale, city officials said. Inspired by a similar plant in Tacoma, the park designed by Seattle engineering firm Contech prevents pollutants like oils, fertilizers and pesticides from entering Ebey Slough and harming aquatic life.



Runoff from downtown Marysville flows into an underground pipe system, directing the water to vaults where heavy debris, like dirt, sinks to the bottom. Then the runoff seeps into the garden’s channels — metal troughs patterned with rows of grasses. As the troughs overflow, water trickles in between stones and plants, sinking into what is called a “media filter” layer made of gravel and mulch. From there, the treated water spills out into Ebey Slough and eventually Puget Sound.

https://www.heraldnet.com/news/at-new-marysville-water-treatment-facility-plants-filter-out-pollutants/