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Recycled Water

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Tanks and purple pipe at former recycled water plant
Former recycled water plant components and pipes

Many buildings on campus are equipped with dual plumbing (also known as purple pipe) to enable the use of recycled water.

Dual plumbed buildings include the Science and Engineering Quad, School of Medicine, and the Knight Management Center complex. The systems have remained intact and active even though the main source of recycled water was eliminated with the implementation of the Stanford Energy System Innovations (SESI) project. Since SESI came online in April 2015 the recycled water system has been fed by domestic water. Formerly, cooling tower blowdown from Stanford’s cogeneration facility was collected as industrial process waste water and treated for use in toilets and urinals. The SESI project, with its transition to a heat recovery system, has greatly reduced the need for evaporative cooling, and hence industrial process wastewater is not produced. As new sources of recycled water emerge, these buildings will be among the first to implement its use.

Codiga Resource Recovery Center

Professor Craig Criddle at a lab bench
Professor Craig Criddle conducting laboratory work

Stanford Water Resources and Civil Infrastructure partnered with the department of Civil and Environmental Engineering (CEE) to construct and operate the Codiga Resource Recovery Center, enabling CEE to expand its research on wastewater treatment processes. Stanford will utilize the Center's findings to inform the potential use of recycled water on campus in the future.

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Stanford's Water Supplies