A visit to a wastewater treatment plant isn’t usually a walk in the park—unless it is the Brightwater Wastewater Treatment Facility in Woodinville, Wash. Mithun designed the facility a few years ago and recently completed an extension called the Brightwater Center, a new 15,000-square-foot education and community space. The center’s design, which achieved LEED

Platinum certification, features folded planes and cantilevered forms that harmonize with the landscape—acres of former auto-wrecking yards converted to public parkland with educational trails, stormwater retention ponds, and a restored salmon habitat.

Why invite the public to the property of a wastewater treatment facility? “King County’s Wastewater Treatment Division is a very progressive entity and recognizes that it’s important to educate residents on the watershed and treatment systems, as well as the protection of the Puget Sound and coastal ecology,” explains Bert Gregory, FAIA, chairman and CEO of Mithun. The division engaged the public early in the project by inviting local educators, businesspeople, environmental groups, and members of the Muckleshoot Indian, Tulalip, and Suquamish Tribes to weigh in on the building’s program.

Based on their input, Mithun divided the Brightwater Center into two wings placed perpendicular to one another. One volume contains exhibition space, a community room that can be subdivided into three meeting spaces, a community room, and a kitchen, while the other accommodates administration space and two laboratories/classrooms. The wings feature eco-friendly materials such as salvaged wood and recycled plastic that are low-maintenance and durable enough to withstand over 6,000 school-age visitors each year. The CMU walls and exposed concrete-slab floors are made with flyash, reducing embodied energy. Beams salvaged from a demolition and other recycled wood products lend warmth to the interior, which can be rented out for events.

In the summer, the building stays cool through natural ventilation, aided by high ceilings and a system of fans and operable clerestory windows. Throughout the day, ample natural light floods through windows and reduces the need to turn on fixtures. Daylight is mitigated by deep overhangs to the east and west and light shelves oriented to the north and south. During the winter, a radiant heating system embedded in the concrete floor warms interior spaces and makes for an inviting seat for students during presentations. The building is also outfitted with a solar hot water system and photovoltaic arrays.

Most of the energy required to heat the building comes from waste methane reclaimed from the wastewater treatment plant—a low-odor process, according to designers. Water is also reclaimed from the plant for non-drinking purposes such as toilet flushing and landscaping irrigation. “Wherever we can use reclaimed water or rainwater, it means we don’t have to import it from remote watersheds or use the energy to treat the water,” Gregory says. Once again, the center reminds visitors to be mindful of how they use our greatest natural resource.