The Most Beautiful Sewage Treatment Plant in the World

Americans’ distaste for all things toilet-related goes deep. Even today, the marketing of toilet paper depends on squeezability, babies, and cartoon bears. The whole nature of human defecation remains somewhat unmentionable, hidden in private places, imbued with code language (restroom, powder room, lavatory, water closet, etcetera) and dismissed with the magical act of the flush.

Beneath this cloak of cultural secrecy lies the problem, one that has had a tremendous effect on the environment. In an effort to “disappear” our waste, cities historically have dumped raw sewage into waterways, threatening wildlife and posing serious health issues to humans as well. Which is why Woodinville, Washington’s Brightwater Wastewater Treatment Plant, possibly the most sophisticated and certainly the most beautiful sewer plant ever built, turns the whole mystery of wastewater on its head. Since opening its Mithun-designed, LEED Platinum Environmental Education and Community Center in 2011, the place has become so popular that it regularly hosts classes, provides habitat for salmon, and even serves as an event venue for weddings.

Yes, brides in white arrive by limo while millions of gallons of sewage per day flow by them via an underground tunnel 18 feet in diameter, the product of 105,000 homes in Seattle metro’s King and Snohomish counties. When weddings are not underway, the on-site educational facility teaches 10,000 program participants that a flush is not a metaphysical disappearance act, but instead an imperfect part of the water cycle.

“We talk about the four ‘P’s: poop, pee, puke, and paper,” says a blunt and enthusiastic Susan Tallarico, who serves as the director of Brightwater for King County Department of Natural Resources and Parks.

Tallarico clarifies that she means only toilet-type paper, designed to fall apart in water, should make the many-mile journey from the surrounding homes and businesses to Brightwater. But wastewater here and everywhere involves a lot of, shall we say, rule breaking. The private nature of bathrooms enables it, and for too many people, the toilet is the convenient place to get rid of things. “Disposable” and “flushable” products are increasingly popular for personal and household cleaning, making up what is now a $6 billion-per-year industry. But that’s money made by the product manufacturers. On the receiving end, at municipal wastewater-treatment facilities such as Brightwater, those products arrive fully intact, unlike toilet paper, and get caught in machinery.

The City of New York, for instance, spends $18 million a year to collect and landfill discarded debris that shouldn’t be in the wastewater stream in the first place—110,000 cubic yards each month. And officials say the volume of this non-degrading matter has doubled in the past five years. This is not just in the United States. In 2013, London resorted to explosives to blast apart a bus-sized glob of various items that threatened to constipate the system.

Teaching better bathroom behaviors is part of Brightwater’s mission, but it also addresses broader issues of water, waste, and return. “This is a story that is not told too often,” Tallarico says. “Most people don’t think about where we fit in the water cycle. We don’t think about what happens when we flush a toilet.” She likens it to the disconnect that exists in much of the Western world with regard to the often hidden infrastructure that allows for the production of cheap food and clothing. Modern conveniences allow new things to show up at our door and old things to disappear seemingly without  a trace.

Of course, nothing disappears, and water is especially limited in this era of climate change and population increase. “People should be worried about their water,” Tallarico says. The Pacific Northwest is enduring drier-than-normal conditions while California and the American Southwest are in serious drought. Farmers on the West Coast are drilling deeper into increasingly depleted aquifers, fearing dried-up orchards that would mean a decade or longer before new trees could produce crops again.

Wastewater treatment, or a lack thereof, has a tenuous history in Seattle (see p. 80), but today, Brightwater expels treated water into Puget Sound in a much-improved state and has negotiated contracts with golf courses, businesses, and local jurisdictions, which use this water for landscaping. According to Michael Popiwny, the capital projects manager for King County’s parks department, the treated water is surprisingly clean, “with very little difference from potable water.” The outflow pipe in Puget Sound, 600 feet underwater and a mile from shore, feeds unsold, reclaimed water into outflowing currents headed toward the Pacific.

Not every municipality on the northern Pacific Coast is so kind to maritime habitats. The seas off the shores of Oregon, Washington, British Columbia, and Alaska are home to thousands of species that range from bald eagles to bivalves, kelp, salmon, sea lions, and gray whales. The otherwise lovely city of Victoria, British Columbia, controversially dumps 34 million gallons of raw sewage every day into the Strait of Juan de Fuca. The Canadian city is now considering a $783 million treatment plant, motivated perhaps by the example set by their American neighbors to the south. Across the globe, raw sewage is commonly dumped into natural waterways, seemingly explained with the axiom, “the solution to pollution is dilution,” despite the fact that such practices have proven unsustainable in the face of population increase.

Popiwny and civic leaders acknowledge that the $1.8 billion invested in the Brightwater plant may be inaccessible to many municipalities. Popiwny says public relations was an important part of his job prior to construction beginning in 2006. “Wastewater treatment is not easy to site,” he says, adding that more than 100 meetings were held to explain to the public how the plant would function, what it would look like, and that it would not smell. “We considered 95 possible locations. Most communities are worried it will be ugly and stink. The facility had to be accepted by the community, had to be a good neighbor, and had to be sustainable. Everything considered, we had to build a high-performance facility. We also were committed to building something attractive that had no odors.”

That odor-treatment equipment added $53 million to the price tag. Brightwater is built on the edge of Wellington Hills, a well-heeled Seattle suburb where homes fetch prices north of $1 million. Locating effluence next to affluence involved both education—tackling that unwanted discussion about what can and should be done with human waste—and cutting-edge technologies.

Engineering for the high-performance facility began in 2002, led by CH2M Hill and Brown and Caldwell. At the core of the system is a membrane bioreactor (MBR). Made up of hollow fibers with microscopic pores, MBRs are able to filter out particulate matter and individual bacteria, resulting in treated wastewater that is seven to ten times cleaner than what is possible through the alternative method, which largely depends on settling tanks and biological activity. MBRs, relatively new to the US but proven elsewhere, also require 40 percent less space than conventional treatment options, which means there is room for the Brightwater facility to expand several decades into the future when population growth may require it. (Already, the facility is planned to accommodate more people moving to the area by 2040.)

MBR systems are more expensive to build and maintain, but the county was committed to running an energy-efficient sewage treatment plant. Beyond the MBRs, several measures were taken to further minimize power use. Special micro-turbine blowers aerate the plant at 30 to 50 percent greater efficiency than traditional systems. The MBR itself requires 50 percent less air-handling. In combination, these technologies reduce annual electricity consumption by 4.5 million kilowatt-hours.

Once treated, Brightwater’s Class A reclaimed water, as defined by the state ecology and health departments, is primarily returned to the ocean. But this water is also acceptable for landscaping and agricultural irrigation, heating and cooling systems, and industrial processing. A golf course in nearby Redmond, Washington, receives reclaimed water for landscaping, replacing stream withdrawal from a salmon habitat.

Biosolids—yes, that stuff—are sent through a dewatering process, digesters, and a centrifuge to become commercially sold fertilizer used by hops farmers, fruit growers, and gardeners. “If we didn’t recycle this, we would have to pay to landfill it, wasting nutrients,” Popiwny says. Digester gas is captured to create electricity on-site while excess heat from the digesters is used for a radiant heating system at the education center.

Relentlessly eco-efficient strategies were in place from the moment Brightwater broke ground, starting with the soils displaced by tunnels and buildings on its 114-acre property. During excavation, the dirt was repositioned on-site to create landforms and buffers designed as part of Hargreaves Associates’ master plan. Had the dirt instead been hauled away, it would have required 37,500 truck trips and tons of fossil fuel. About 15,000 cubic yards of compost material left behind by the previous site occupant, a landscape business, was worked into the landscape, while 67 percent of construction and demolition materials (370,000 tons) were reused in building the new facilities.

Before the first foundation was laid, however, workers restored a salmon habitat, reclaiming a stream corridor of 1,700 feet that had been routed through culverts, parking lots, and ditches. Popiwny says this was important to show the surrounding community that the project team could make good on its environmental goals from the start.

Brightwater Center’s LEED Platinum certification is appreciated by more than the fish and occasional seagull. As Tallarico explains, the majority of the 10,000 people who have come each of the three years since opening in 2011 is not made up of casual tourists coming for a tour—they come to learn about water systems and their local environment. “This fills a hole in education in the north end of Seattle,” she says. Tours for school groups typically take four to five hours, and schoolteachers often connect the field trip experience to what they are learning in the classroom for a fuller learning experience. Students study types of water habitats by way of the salmon stream and ponds in the 70 acres of public natural areas. Field trips and summer day camps are sponsored by an organization called IslandWood, which uses nature as a platform for teaching science, self-awareness, and stewardship in a fully immersive experience.

Schoolteachers can also earn continuing education credits at Brightwater while learning about the environment. Community groups attend classes where they are taught the benefits of using biosolids to enhance their garden beds. “We show them two carrots: one raised in our biosolids compost, the other in regular soil,” Tallarico says. “The bigger carrot grows in our waste.” This learning takes place in Mithun’s geometric structure, which cantilevers over a wetland area and is detailed with reclaimed wood, polished concrete, and extensive daylighting in interior spaces.

An art program appropriately complements the contemporary building. King County requires that a proportion of expenditures for building projects (about one percent) be used to commission works by local artists, and Brightwater’s installations are not simply canvases that might look nice over a sofa. They are site-specific, created for and about the nature of wastewater treatment. Before beginning, selected artists toured the treatment facility and learned about the reclamation work at Brightwater. What came out of that exercise included sculpture, film, kinetic art, and blown and etched glass that all relate to the microbes, water flows, and other very real parts of what happens here.

The mission is to pull back the curtain that so far has hidden our shortsighted approach to wastewater treatment. By combining new technologies, smart design, and site-specific art, Brightwater is making good on that mission. The neighbors are happy, the salmon are spawning, and the next generation of environmental stewards knows exactly what happens after they deposit their four “P”s into the water cycle.