Designing for a dry world

When architects were designing a new 200,000-square-foot biotechnology lab in 2009 to accommodate the University of California, San Diego’s burgeoning student population, the Golden State was in the midst of a withering drought.

No surprise then that water conservation became a focus of the team at Portland’s Zimmer Gunsul Frasca Architects. They created a system to harvest condensate that collects on the building’s air conditioning coils during hot summers. That water – supplies of which grow as temperatures rise and the air conditioning is cranked up – is piped elsewhere to irrigate the campus during dry months.

The university, which is seeking LEED Platinum certification for the lab, will also reclaim much of the wastewater from the building’s 150,000 square feet of wet bench labs and restrooms as well as from the air conditioning system. That should help slash use of potable water by 360,000 gallons annually.

“I expect to see this become much more widespread,” says Joe Collins, a partner at ZGF. “Within a couple of years, projects that use drinking water to flush toilets will cause people to say, ‘What are you thinking?’”

With climate change expected to increase the length and severity of droughts in the western United States and reduce the mountain snowpack that supplies fresh water to states like California, proponents of water-efficient design argue it will soon move from trendy to mandatory.

Droughts notwithstanding, one of the top reasons to be interested in reducing water use is the financial bottom line. Water rates rose 5.6 percent between 2001 and 2009 for a commercial customer using 100,000 gallons of water during a billing period,  according to a Black & Veatch survey. Industrial customers using 10 million gallons in a billing period saw their bills go up more than 6 percent.

New construction projects are leading the way toward water efficiency. They are often doing this by installing systems to treat and re-use storm water and gray water on site, something that is usually too expensive to introduce on a building-retrofit project. (Of course, water efficiency measures also help rack up points needed for LEED certification by the U.S. Green Building Council.)

Collins at ZGF notes that savings like those achieved at the UCSD lab can be replicated if design teams try to understand overlooked resources inherent to each site and in each building.

“We’re used to stepping back from each project on each site to really understand what we’ve already got,” he says. “You almost always find something that is useful. But you have to be attuned to it and let it impose solutions instead of the other way around.”

 Meanwhile, the growing interest in EcoDistricts – neighborhood-scale sustainability efforts – is another driver in the water-efficiency movement.

In the ideal EcoDistrict, energy is produced onsite, often using an existing waste stream, such as food scraps from local restaurants. Wastewater and storm water runoff from neighborhood buildings is also reused for irrigation and toilets.

“People are starting to think about water as a community resource and as a finite resource,” says Doug Sams, an associate partner and sustainable designer at ZGF.

He worked on a new building for the Port of Portland that is expected to use 75 percent less water than a standard office of the same size.  The Port building, which is located close to the Columbia River, treats wastewater and collected storm water using a Living Machine – a man-made tidal wetland installed by Worrell Water Technologies.

Wastewater from the building is collected in two 10,000-gallon tanks where coarse solids are removed and the water is stored so its flow through the system can be controlled. From there it runs through six watertight containers that contain gravel-like material and an assortment of native and tropical plants. Beneficial microorganisms clean the water before it is disinfected and sent to back to the building for non-potable use.

The entire system – which is located at the building’s entrance and in its lobby – cost nearly $750,000 to design and install and more than $14,000 each year to operate.

Only seven Living Machines have been installed with another eight in design and construction, mostly for governments and non-profit organizations. Obtaining local government approval for such systems can be difficult due to concerns over re-using wastewater, according to Will Kirksey, senior vice president at Worrell Water Technologies.

The cost of treating wastewater may start making even technologies as expensive and ahead of the curve as the Living Machine palatable to more clients. The Living Machine at Port of Portland has a 60-year payback period because of low water rates in the area and a nearby sewer connection, Sams says.

The port chose to install it as a demonstration project because the city is considering a plan to decentralize its waste water system, according to Kirksey.

But payback periods for Living Machines vary depending on where they are installed, he notes.  A Living Machine the company installed at a North Carolina school saved it $4.5 million because it is located seven miles from the nearest sewer line. Rising sewer treatment prices may also play a role in making onsite water treatment a financially viable decision. 

Currently though, wastewater and sanitation don’t get the attention they deserve, according to Kirksey.

As much as 70 percent of water consumed  in the United States is for non-potable use, yet the vast majority of it is treated to drinking standards, he The move toward increased water efficiency in construction projects is in its nascent stages. Overall, the cost of water is very low, says Barry Giles, CEO of California-based BuildingWise, a green building consulting firm.

Attention to water in sustainable design is growing, but water is “far, far too cheap,” he says. “We pay too little for our water.”