A dynamic and sustainable design
US utility DC Water has scooped a prestigious architectural award for its “HQO” building that incorporates sophisticated rainwater harvesting and thermal recovery from wastewater.
The American Institute of Architects (AIA) announced the award for architecture as well as a Jury Citation for sustainable design.
Completed in 2019 for DC Water, the sewer and water utility serving the District of Columbia and several suburban jurisdictions, the project was developed as a design-build collaboration between Smith Group and Skanska.
Smith Group said they wanted to “create a building that wasn’t utilitarian but dynamic and boldly referential of its sustainability mission”.
As well as mimicking the “fluidity of water”, the design also overcomes a unique constraint on the site: a narrow wedge of land in the floodplain of the Anacostia River.
The plan needed to maintain and protect the existing mid-20th-century pumping station along the northern edge of the site, as there wasn’t enough space to avoid the existing structure, according to the group.
LEED-ing the way with rainwater harvesting
The HQO building was designed to be LEED Platinum Class A, the highest class in green building leadership.
The utility said that it "includes almost every state-of-the-art environmentally sustainable feature used in modern construction".
Built to use 72 per cent less potable water than a typical office building, DC Water’s office takes advantage of a sophisticated rainwater harvesting system.
A green roof reduces stormwater runoff and contains lush native plantings that absorb rainwater while helping to buffer the terraces from the wind.
Rainwater not absorbed by plants is then collected through runnels in low impact development planters.
It is then routed to a large underground cistern before being sent to the pump room to be filtered and treated to remove impurities.
Treated rainwater is stored in a day tank in the lobby to be later used for irrigation and toilet flushing.
Wastewater heat and solar heat gain
Another innovative part of the building design is that DC Water can use its own wastewater as a source of thermal energy.
Before being pumped to the utility’s Blue Plains Advanced Wastewater Treatment Plant, wastewater is pumped from a wet well to a “SHARC” system.
This filters and separates wastewater and solids with a heat exchanger, which transfers heat energy to and from filtered wastewater into clean water.
In the summer, heat is transferred to the wastewater, and in the winter, heat is taken from the wastewater.
DC Water was the first building in the US to use the SHARC technology for both heating and cooling.
“The building’s unique location over the two operating pump stations provide an uninterruptible, limitless supply of thermal energy,” said Canadian company, SHARC Energy Systems.
Furthermore, environmental considerations such as daylight and solar heat gain within interior spaces were considered to “create a comfortable environment for staff and visitors”.
Four categories in design awards
The annual AIA|DC Chapter Design Awards competition is open exclusively to registered architects and invites submissions in four distinct project categories:
Urban Design/Master Planning.
The jury may then recommend one of the following: Citations in the areas of Sustainable Design, Universal Design, Design and Wellbeing, and Urban Catalyst; Award; and Grand Award.