This facility processes various recyclable materials and sees high truck traffic. It discharges to the Lower Duwamish, a 303(d)-listed impaired waterbody.
The lack of available space onsite was a key factor in the design of this stackable multi-media treatment system. The system takes up roughly one parking stall, and it also has relatively low O&M costs compared to an active treatment system.
Since the installation of the treatment system, this facility has achieved consistent attainment on all applicable ISGP parameters.
Raw stormwater flows through an oil and grit settling cell before being dispersed over the adsorptive filtration media in the top and bottom tanks. Prior to installation, bench-scale testing was conducted using raw water from the site to determine the most effective combination of treatment media.
An upright settling tank was added in 2019 to reduce solids reaching the treatment system and prolong the usable life of the media.
