Thursday, May 5, 2011

Zero Water Buildings

In one of Seattle's most urban neighborhoods, a small elementary school is trying to wean itself off the city's water grid.

The classroom toilet composts and treats waste on site rather than flushing it into city sewer pipes. Water washed down sinks doesn't flow into storm drains but recirculates to a 14-foot-high wall filled with plants, which will eventually soak it all up. For now, excess flows through the wall.

Plenty of "green" buildings strive to generate as much energy as they use, but Bertschi School's new science building is one of dozens nationwide taking it a step further. They're attempting to unplug from the municipal water and sewer system to collect, recycle and reuse water and wastewater on site, a concept often referred to as net zero water.

The U.S. Army has a goal for several installations to reach zero water, energy and waste use, and last week it designated Fort Riley in Kansas, Camp Rilea in Oregon and Joint Base Lewis-McChord in Washington, among others, to be net zero water. It also named other installations to strive for net zero use for energy and waste.

This month, the University of Miami broke ground on a college dormitory that will reuse all water from showers, toilets and laundry for everything except drinking and cooking. With a $2 million grant from the National Science Foundation, researchers are developing an onsite system to convert wastewater into potable water while treating for pharmaceuticals and other contaminants.

"Water is a looming issue after energy," said James Englehardt, a professor of environmental engineering at the University of Miami who is spearheading the project. "Energy and water are intimately linked. We have plenty of water, but it takes a lot of energy to purify it."

Despite Seattle's image as the land of plenty of rain, water conservation is a concern here because summer months can typically be dry.

Proponents say the Seattle school project and others like it recognize water as a precious resource. Treating waste and runoff on site also means reducing the land, infrastructure, energy and chemicals needed to convey water to faucets and later to treat what flows down toilets and bathtubs.

"People are recognizing the limitation of the planet and what's available," said Eden Brukman, vice president of the International Living Building Institute, which runs the "Living Building Challenge," considered the most rigorous green-building performance standards. In the U.S., two projects in Eureka, Mo., and Rhinebeck, N.Y., have been certified as living buildings...

Urban buildings unplug from water grid
Phuong Le, Associated Press
Sun Apr 24, 2011

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