North Transfer Station

Undoubtedly one of the most community-friendly dumps in America, the North Transfer Station is located in Seattle’s thriving Wallingford-Fremont neighborhood. From the outset, the Mahlum design team and Seattle Public Utilities partnered with the neighborhood to find solutions that met everyone’s needs. One of the primary community requirements was that the new facility would not rise higher than the height of the original 1967 building. This limitation significantly influenced how the design team shaped and organized the facility.

Tri-chorded steel trusses were used to meet the low height requirement and create the 200-foot clear spans necessary for the 57,000 SF tipping floor. Skylights are embedded along the top of each 6-foot-wide truss, distributing daylight evenly across the space. A wall of translucent polycarbonate panels above trash compactors and exhaust equipment along the south façade supplements the skylights. The panels introduce diffused light, which adds brightness without shadows to enhance safety. The panels also help avoid heating the trash, which limits its off-gassing. Processing trash and recyclables for future disposal can impose negative environmental impacts. Odor, dust, noise, and vermin are natural byproducts of a typical facility. With extensive input from the community, the design team addressed these factors holistically to minimize their impacts.

To buffer internal activities from adjacent properties and reduce noise pollution, the new facility is set down into the site and a concrete retaining wall placed along the northern border acts as a sound wall. The garage doors are ultra-quiet and operate at high-speeds for each vehicle accessing the buildings. The powerful mechanical system thrusts exhaust air high into the atmosphere to decrease odor pollution. A low-flow misting system above the tipping floor limits dust. Every surface of the site is employed to improve environmental conditions.

Above the tipping building, an array of PV panels generates 150kW power, enough to supply 10-12 homes on an annual basis. Above the 10,000 SF administration building and 10,000 SF recycling building, green roofs filter stormwater, decrease runoff, and reduce the site’s heat island effect. In the public park areas, sidewalks and sport courts are composed of pervious concrete, which allows water to penetrate directly into the ground. An on-site catchment system is integrated into the landscaping to filter discharge from trash and recycling materials. The catchment system discharges the cleaned grey water directly into Lake Union, reducing the volume of water sent to the wastewater treatment plant.

The design of this LEED Gold certified facility also strives to connect the community to the important functions of the station by putting trash and recycling processes on display. A viewing room above the tipping floor in the administrative building is open to the public and is popular for school field trips. Along the south side of the site, which faces the busy Burke-Gilman Trail, windows have been punched into the wall to allow public views down into the underbelly of the tipping floor.