Toilet-To-Tap Programs Conserve California Water

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According to the California Department of Water Resources, 2013 closed as the driest year on record for many areas of the state. And there’s no end in sight. The DWR’s first snowmelt runoff forecast for 2014 suggests that if conditions don’t improve, 2014 will be a “critical dry water year” for the Sacramento and San Joaquin River systems. 

This situation has elevated the importance of toilet-to-tap projects like that at the Orange County Water District. There, the district’s Groundwater Replenishment System (GWRS) processes 70 mgd of treated wastewater into potable water. 

“The advantage of treating and reusing wastewater is that this water is already available locally so it is not exposed to political risks (such as) reduction of water that can be imported,” says Jean-Daniel Saphores, a civil and environmental engineer at the University of California at Irvine, in a recent NBC interview

After wastewater is treated at the Orange County Sanitation District, it flows to the GWRS where it undergoes a purification trifecta: microfiltration, reverse osmosis and UV disinfection with hydrogen peroxide. At this point, the water is of near-distilled-quality, but to further eliminate the “ick factor” for customers, the water is then pumped to percolation basins in Anaheim where the water naturally filters through sand and gravel to deep aquifers of the groundwater basin. 

The Orange County Water District, which has been producing potable water since the mid-1990s, is currently expanding operations that will increase potable water output at the plant to 100 mgd by 2015. The plant is already the world’s largest for water purification and potable reuse, but the expansion, which is currently 65 percent complete, puts the plant in an international spotlight. And with good reason, considering the drought conditions faced in Orange County are also being encountered in other countries. According to an article on, the plant has hosted officials from Japan, the United Arab Emirates, and has seen interest from England and even Singapore. 

One of the greatest hurdles for water reuse programs like the one in Orange County is public acceptance. In Singapore, the NEWater Visitor Centre builds comfort level by pointing out that reuse happens on the small island nation regardless of whether it’s intentionally designed: discharged effluent eventually makes its way to a water treatment plant. 

And as public understanding grows, so, too, will public acceptance of toilet-to-tap programs. 

“Almost one in five Californians are already connected to a utility that uses, or has (as) part of its water supply portfolio potable reuse,” says Dave Smith, managing director of the WateRuse Association’s California Chapter, to 

The current drought conditions in California only work to expand the need and acceptance of this economically practical solution. 

How has your facility increased public awareness — and acceptance — of water reuse programs like Orange County’s? Post a comment below.


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