Water System
A variety of methods are used in the building to conserve and manage water, including the following: rainwater harvesting; a green roof and a bioswale to treat graywater; and composting toilets. All water used on site must be collected from rainwater, and all wastewater and graywater must be managed and treated on site (net-zero water).
The theory of water-less waste,wastewater use and water washing
Rainwater Harvesting System
Up to 500 gallons can be filtered per day.
The Bullitt Center has systems to harvest and filter all rainwater that falls on the site, so that all water consumed at the Bullitt Center will come from rainwater that has been collected and purified on site. However, the permitting process necessary to allow the center to use the filtered and potable rainwater has been very slow moving. The glide path is clear and all the equipment is installed; but 18 months after construction was completed, the building manager still has not been certified to operate a public water district. (This was slowed down by an unrelated decision by the foundation to switch building managers midway after the first year.)
The process involved meetings with the U.S. Environmental Protection Agency, the Washington State Department of Ecology, the Washington State Department of Health, the King County Department of Public Health, and Seattle Public Utilities. As of early 2015, the Bullitt Foundation is seeking approval from the Washington State Department of Ecology to become an independent water district.
The Bullitt Center has proved that it can meet the water demands of all the building’s users through rainwater harvesting by collecting and filtering more rainwater than it takes in from municipal sources.
Wastewater filters through the
constructed wetland
Graywater Filtration
The park also serves as the last step in the Bullitt Center’s graywater filtration plan. The water from the sinks, showers, and dishwashers is collected and stored in the basement. From there it is filtered and then pumped to the constructed wetland, a small green roof located outside on a third-floor terrace. Comprising horsetails (Equisetum) planted in a bed of shale, the wetland adds a touch of greenery to the building’s Madison Street facade. The hardy plants draw out nutrients, such as nitrogen and phosphorous. A complex system of microbes in the shale breaks down organic matter, while the plants consume the water and then release it into the atmosphere via their normal evapotranspiration processes. Any remaining graywater is then sent to a bioswale at the property’s southwest side filled with crushed gravel that extends to the water
The constructed wetland (a green roof on a third-floor terrace)
table. Like the wetland, the bioswale is planted with horsetails. The remaining water then slowly soaks into the ground under the park where it eventually becomes part of the region’s groundwater reserve.
In addition, the downward slope into the neighboring park created opportunities for graywater infiltration.
Basement Green Systems
The basement is a major hub for the building’s many green systems. It is the location of the following: the ten composting toilet bins and their leachate tanks; the 56,000-gallon rainwater cistern; the water filtration and ultraviolet purification system; the heat pump for the geothermal system; and graywater storage. (Any trace gas from the compost bins in the basement is vented on the roof.) The basement also is home to a collective server room, which also houses the “brain” of the Bullitt Center’s nervous system. By concentrating each tenant’s server resources in one room, the building is able to cut down on the energy consumption associated with mitigating the heat produced by the servers.
Water is also conserved through the use of composting toilets. Since the building was first occupied, the toilets and composting processes have worked as expected. Less than half a cup of water is used to flush the toilets, and both liquid and solid wastes are disposed of in ways that improve or remediate environmental and ecologic processes.
The composting toilet in the Bullitt Center
Dashboard Control System
To help tenants manage their energy and water consumption, the foundation has created Dashboard, a web application that displays consumption patterns in real time. Because one of the foundation’s goals is to educate architects, engineers, contractors, developers, bankers, appraisers, and the public about what is possible with current green technologies, the information on Dashboard is available to all.
The water usage of dashboard