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In addition to studying natural systems like wetlands and storm water, researchers and engineers with the new Engineering Research Center for Re-inventing America's Urban Water Infrastructure plan to build working prototypes of new wastewater treatment systems at Stanford.

Craig S. Criddle, a Stanford professor of civil and environmental engineering and an expert on wastewater treatment, said he's thrilled to be part of the effort. "This Engineering Research Center (ERC) is a great platform for tackling wastewater issues," said Criddle, a senior fellow at the Woods Institute for the Environment. "I'm excited about how it pulls people together who normally wouldn't be interacting. How often do university researchers get to work closely with the people who manage campus utilities?"

The power of sewage

Criddle and his ERC collaborators plan to field-test a method of extracting energy from wastewater on the Stanford campus. They're working with Stanford Utilities to develop pilot-scale test facilities for treating wastewater drawn from the sewer that runs along El Camino Real. The treatment system could potentially be powered by the energy it recovered from the wastewater itself.

"We first need to develop and test technology at the pilot-scale using real wastewater," Criddle said. "Then we can scale-up."

Dormitory? Laboratory? Both!

In another ERC project, Criddle and his colleagues hope to work with campus planners to build a new Stanford dormitory outfitted with its own water treatment systems for water reuse and energy recovery. For example, they propose to install new systems for treating greywater - the soapy water from washing machines and showers. The treated water could be used to flush toilets, wash clothes, or irrigation.

Criddle said that this kind of localized treatment, also called "distributed treatment", can provide a safe and economical supply of water for non-potable applications such as irrigation for landscaping. "Basically, distributed treatment means you're treating wastewater where it's being generated, then using it locally," said Criddle. This could be done an entire campus or just for a single building.

Distributed treatment is a big shift from current practice, Criddle said. Currently, Palo Alto, like most cities, uses centralized wastewater treatment in which a network of sewers guides wastewater downhill to a treatment plant. The plant treats water from a large area, including Palo Alto, East Palo Alto, Mountain View, Los Altos, Los Altos Hills and Stanford. Pumping treated water back uphill from the plant for reuse takes energy and can be expensive, but in distributed treatment systems the energy and pumping costs can be much lower because the water doesn't have to go as far.

Beyond Stanford

ERC funds will also enable Criddle and his colleague David Freyberg, a hydrologist in civil and environmental engineering, to continue ongoing collaborations with the City of Palo Alto and Stanford Utilities. Stanford researchers and the city began working together in 2004, thanks to an Environmental Venture Project grant from the Woods Institute. Now, they're developing software tools that will help planners to design water and wastewater systems that are cost-effective, energy-efficient and can withstand extreme conditions like flood or drought.

"Our collaborators from the City of Palo Alto and Stanford Utilities are helping us to understand which software tools will be most useful," Criddle said. "There are many ways to organize new infrastructure, and we want to develop practical tools that will allow planners to run simulations and to make design decisions that give the biggest bang for the buck."

Part 1 of story … read about creative solutions for urban water infrastructure.

Sascha Zubryd is a science-writer intern at the Woods Institute for the Environment.