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The Water Cycle (with a Decidedly Human Twist) The Water Cycle (with a Decidedly Human Twist)

The Water Cycle (with a Decidedly Human Twist)

by Bernadette Clavier
June 17, 2010

Water Cycle With a Human Twist

Earlier this spring, a group of students from the Stanford Graduate School of Business took a trip through California and Nevada. Their mission: to investigate water. The trip began in Sacramento with a tour of the Delta, following the flow of water south. The group visited agricultural communities in the San Joaquin Valley, then continued down to Los Angeles and Orange County, to learn more about urban water use and corporate water management—finally examining Nevada's water use through the lens of Las Vegas.

Along the way, the group met with policymakers, corporate executives, nonprofit leaders, water managers, and farmers. Students investigated ecosystem protection, water economics and markets, wastewater treatment and recycling, water infrastructure, the water-energy nexus, water quality issues, corporate water footprinting, and climate change, to name but a few.

Here is the third installment of what they found:

Remember what your middle school science teacher told you about the water cycle? Water evaporates, condenses in clouds, travels across the land, precipitates as it encounters elevated land, and penetrates below ground or accumulates in surface lakes until it eventually flows towards the ocean. 

But when you hit grad school and were determined to dig up the story yourself by putting together all the pieces of a very fragmented system, here's what you learned the water cycle really looks like (see above). The natural system seems to have taken a few twists and turns under the influence of not only ignorance but also the genius of the human species.

The Orange County Groundwater Replenishment System represents a unique twist to the complex urban water supply cycle. Using a mix of microfiltration, reverse osmosis, UV and hydrogen peroxide treatment, OCGWR treats 70 million gallons of sewage each day and converts it into safe drinking water. That’s enough water to meet the needs of 500,000 people. Ironically, the outlet of this wastewater recycling plant has some of the purest water in the county. In fact, the water coming out of the OCGWR plant is so devoid of any mineral salts that an additional process is required to add these back in, just to make it drinkable.

Sewage recycling would probably never be characterized as sexy but there is much to be excited about in OCGWR. Its cost of water is competitive, even without significant subsidies. Its energy consumption, though substantial, is only half of that required to pump water from Northern California to Orange County. The treated water allows Orange County to maintain its groundwater at sustainable levels and to prevent saltwater intrusion into its aquifer.

However, the real genius of the project lies in the fact that it has convinced the residents of one of the country’s richest counties that the toilet is a viable source of drinking water (albeit one with a $500 million plant standing between their toilets and their faucets).

Bernadette Clavier is the Associate Director of the Center for Social Innovation at Stanford's Graduate School of Business. In her spare time she created an organic food program for Bay Area schools, trains as a disaster first respondent, and advocates for autism spectrum disorders awareness.

A version of this post appeared at Stanford Graduate School of Business' Center for Social Innovation.

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