Diagram of the water and wastewater managment systems in the Bullitt Center. Rainwater captured from the roof is collected into a cistern for reuse in both potable and non-potable uses. Excess rainwater is combined with the building's graywater and released in constructed infiltration swales, recharging the aquifer. Human waste from urinals will be stabilized and stored for use as fertilzer.
Credit: Jameson Simpson/Original diagram courtesy the Miller Hull Partnership
When planning for waste management, what may first come to mind is human waste and trash. However, buildings generate waste well before any ground is broken. It starts in the design firm’s office by way of discarded drawings, as well as with the conversion and transmission wastes in sending electricity to power-hungry office equipment. When the building reaches its end of life, demolition will generate even more waste.
Zero waste is just one component of the International Living Future Institute’s Living Building Challenge (LBC). “The conservation and reuse imperative within the program asks teams to look at waste not just from a construction waste perspective, but from?…?design, construction, operation, and end of life,” says Amanda Sturgeon, FAIA, vice president of the LBC program.
In the construction phase, waste must be completely diverted from the landfill. “People generally have to source separate waste management channels or create a particular contract with their waste hauler,” Sturgeon says. “If they just send it commingled, they can’t guarantee rates of conversion.” Once in operation, a building must generate energy on site and adhere to strict consumption limits. Garbage and food scraps must be recycled to the extent possible.
And, of course, human waste must be addressed. LBC certification “requires all wastewater to be infiltrated or reused on site,” Sturgeon says. Project teams are encouraged to consider closed-loop water recycling systems, which reduce water usage and eliminate wastewater discharge. Some teams separate the three wastewater streams—black-, gray-, and stormwater—and address each individually. The possibilities are many, but so are the complexities. One challenge is regulatory barriers, Sturgeon says. Many municipalities heavily regulate or even ban onsite treatment of graywater or blackwater.
Even greater is the challenge that Sturgeon calls “social-behavioral”—for example, a market-driven developer who gets nervous about installing composting toilets or graywater systems, and tenants who may be reluctant to use or maintain these systems.
The Bullitt Center, in Seattle, plans to achieve 100 percent on-site renewable energy, water, and waste management.
Credit: Benjamin Benschneider
None of these challenges deterred the Miller Hull Partnership from designing a zero-waste commercial building. The Bullitt Center in Seattle, which officially opened this past April and is the headquarters of the Bullitt Foundation, plans to achieve 100 percent on-site renewable energy, water, and waste management. The six-story, 50,000-square-foot office building operates 83 percent more efficiently than a typical Seattle office building.
“We recognized early on that this wasn’t the typical project, and that we were going to have to think about solutions in different ways,” says Brian Court, AIA, an associate at Miller Hull. “It was really a performance-driven design process.”
In terms of supply, net-zero water posed little challenge. “One thing we have going for us in Seattle is more rain than we know what to do with,” Court says. A 30-foot-square concrete-lined room in the center’s basement serves as a cistern. With a 50,000-gallon capacity, it can hold three months’ supply of water—enough to outlast the region’s summer dry season.
What to do with the water next involved quite a bit of red tape. “Regulatory issues are extraordinarily complex in Washington state,” Court says. “Commercial structures are not allowed to use rainwater for potable use.” So, he says, Bullitt Foundation president and CEO Denis Hayes “spent a lot of time knocking on doors” in the county and the state departments of health, and then the U.S. Environmental Protection Agency. His persistence paid off and the project was granted a regulatory pathway to supplying potable water on site, which should be completed within months. In effect, the building will serve as its own public water district and be held to the same standards. The center’s building engineer even became trained as a water district manager.
As a water district, the building will have to chlorinate the water, which the team had hoped to avoid due to the potential adverse health effects. Thus, off-the-shelf filters at discharge points throughout the building will remove the chlorine from the water. Call it a water treatment Catch-22.
The site also reclaims graywater from the building’s sinks and showers. Wastewater collected in a basement holding tank goes to a 15-by-60-foot constructed wetland on the building’s third floor for microbial treatment. Then it filters through two 8-by-50-foot planting beds in a city park outside one of the center’s entrances. “We did a lot of negotiating with the city, county, and state agencies because there was no precedent,” Court says. “It opens up an interesting theory on how we use the public right of way. … It makes a lot of sense that buildings in cities should use that [land] for graywater treatment or infiltration.”
At the six-story Bullitt Center, designed by the Miller Hull Partnership, the foam-flush toilets empty into 10 Phoenix composters in the basement.
Credit: Benjamin Benschneider
Simple composting toilets eliminated the need for a blackwater treatment system—which code officials would view warily anyway. Direct drop wasn’t possible due to the building’s size so the team settled on foam flush toilets that use soap and only a teaspoon of water per flush. The toilets empty into 10 Phoenix composters—aerobic plastic units filled with woodchips—in the basement. The units will be emptied annually, by Phoenix for the first year and subsequently by the building’s management company or a subcontractor, and the soil will be used as compost.
The regulatory hurdles made Court reconsider the challenge of urban building. “The solution to global issues isn’t a bunch of space station buildings,” he says. “The real solution is at the next level—the neighborhood or eco-district level—with buildings working together. Not every building needs a waste treatment plant or energy generation plant.”
On the opposite coast, a similar philosophy informs the project team behind Bright ’n’ Green, a multifamily residential building in Brooklyn, N.Y., that is wrapping up two years of construction. Developed by local design firm Scarano Green Services, the zero-waste redevelopment will feed reclaimed rainwater collected in the crawlspace storage area in cisterns to the site’s green spaces and irrigate the landscape in a five-building radius.
Graywater from the six-unit, 7,000-square-foot building will be treated by UV filtration and then pass through a biofilter in three glass-walled chambers—intended as a design element—on the building façade. The water will then pass through a carbon filter, a second UV filter, and finally into a 5,000-gallon storage system for use in flushing toilets. Aquatron composting toilets in each residential unit will direct liquid and solid human waste to a composting bio-chamber in the basement, where red wiggler worms will transform it into vermicompost.
Designed by Consilience, the Potomac Watershed Study Center is aspiring for Living Building status.
Credit: Courtesy Consilience
Convincing those involved with the project’s design, review process, and construction to think differently has posed the biggest challenge, says Bright ’n’ Green project manager and designer Yuriy Menzak. But the onus of maintaining the project’s intent will fall on the occupants who must conserve energy and limit their water consumption—all closely tracked by in-unit dashboard monitoring systems.
A third project aspiring for Living Building status will achieve zero waste through integrated campus design. Designed by Sandy Wiggins, founder and principal of Philadelphia’s Consilience, the Potomac Watershed Study Center (PWSC) will be located at Hard Bargain Farm, a 330-acre working farm owned and operated by the Alice Ferguson Foundation in Accokeek, Md. The Hard Bargain Farm Environmental Center, an educational program, uses the farm and the surrounding woodlands and wetlands as a classroom. Targeting completion in 2015, the PWSC will include an overnight lodge, a day-use building, sleeping cabins, and a boardwalk over the wetlands. It will employ rainwater collection and composting toilets in the lodge and day-use building. Graywater from the overnight facility will feed infiltration beds planted with native flowers and wetland vegetation.
Like the other two projects, the PWSC will encourage users to reduce consumption. However, the center will itself become an integrated teaching tool for environmental stewardship. Visiting school groups will be given a budget for energy and water. Integrated monitoring systems on showers, sinks, and electrical outlets will provide feedback on energy usage relative to other groups.
Lori Arguelles, executive director of the Alice Ferguson Foundation, hopes the new center will help teach visitors to think and act differently. “Landfills are filling up,” she says. “We have to be far more creative and innovative in how we deal with waste as a totality in the future.”