As the California drought worsens, some communities such as Orange County, San Diego and the Silicon Valley are expanding water recycling programs, and support for "toilet to tap" programs appears to be growing from a once-squeamish public.
"Because a lot of communities are running out of water, they sort of have to explore all their options," said Janny Choy, research analyst with Water in the West, a program of the Stanford Woods Institute and the Bill Lane Center for the American West at Stanford University. "Recycled water is certainly one piece of the puzzle, but it's probably not going to be the answer to solve everybody's problem."
The Silicon Valley Advanced Water Purification Center, located in San Jose, began operations last year and produces up to 8 million gallons per day of purified water from wastewater (Tweet This). The facility was built at a cost of $72 million in a partnership between the Santa Clara Valley Water District (SCVWD) and the city of San Jose. The facility treats wastewater that would otherwise go into the San Francisco Bay for use as reclaimed water in irrigation, construction and industrial uses. They eventually hope to use some of the purified water to refill groundwater sources.
The Santa Clara County facility gets wastewater from the cities of San Jose and Santa Clara, and the goal had been to expand the recycled water to make up at least 10 percent of total county water demand by 2025. But due to the 4-year-old drought, the water agency is pushing its goals further: It's pursuing plans to expedite that goal by three years—to reach the 10 percent number by 2022—and partnering with other cities in the county to purity their water.
"It's a drought-proof supply, and it's also a local supply," said Colleen Valles, a spokesperson for the SCVWD. She said the water agency has five projects pending and is looking at expanding the recycling program in the county.
Meanwhile, the Orange County Water District (OCWD) is undergoing an expansion of its own at the water agency's high-tech Groundwater Replenishment System in Fountain Valley, California. The $481 million plant has been operational since 2008 and currently processes about 70 million gallons of treated sewage wastewater each day into drinking-quality water that goes into groundwater basins for later reuse as potable water. OCWD, which serves more than 2.4 million people, is spending $142 million to increase capacity at the facility to approximately 100 million gallons per day, or enough water for 850,000 residents.
"Recycled water is a huge benefit," said OCWD General Manager Michael Markus. "We can produce the water for about half the energy it takes to import water from Northern California and about a third of the energy it takes to desalinate sea water."
Orange County's plant, for example, can produce recycled water for about $480 an acre-foot—well below the estimated $2,000 per acre-foot a new desalination plant in nearby San Diego County will be paying for new water. Similarly, the recycled water runs about half the roughly $1,000 per acre-foot price of water from the Metropolitan Water District, the giant water wholesaler for Southern California, which on Tuesday announced a 15 percent reduction in the amount of water it will supply to its 26 member agencies.
The OCWD wastewater treatment facility, the largest advanced water purification facility in the Western Hemisphere, uses a three-step water treatment process: micro-filtration, reverse osmosis and ultraviolet light with hydrogen peroxide disinfection. The plant uses about 13 megawatts of power per day, or the equivalent of power to supply 7,500 to 12,000 homes.
"You hear some people talking like, 'I don't want to drink toilet water,' " said Henry Vaux Jr., professor emeritus of Resource Economics at the University of California at Riverside. "Once it's gone through three stages of treatment, the water that ultimately goes out of there is cleaner than they got and flushed away."
California law allows treated wastewater to be used for indirect potable reuse, such as sending the purified water into groundwater basins for capture later as a source of drinking water. A state bill passed in 2013 requires that California's water regulators create a framework for direct potable reuse by the end of 2016.
"While it appears to be likely that the science and available technology will support a positive recommendation to move forward with authorizing DPR (direct potable reuse) through regulations, there is no assurance at this time," according to Richard Mills, chief of the Water Recycling and Desalination Section of the California Department of Water Resources. In an emailed response, he also indicated that if there's a recommendation to go ahead with direct potable reuse, then the process could take "one or more years depending on the complexity of writing the regulations."
Purified wastewater could provide enough potable water to supply all municipal needs for more than 8 million people, or roughly one-fifth of California's projected population for 2020, according to a report released last year and sponsored by the WateReuse Association, an organization supported by water utilities and companies that promote water reuse. The report also pointed out that NASA and the International Space Station already use a technology that produces potable water for six crew members from a combination of condensation and collected urine.
In 2014, two Texas towns launched the nation's first direct-to-potable reuse water programs. Wichita Falls and Big Spring, about 230 miles apart, treat wastewater with a multistep cleaning process and then send the purified water directly to homes. The last U.S. Drought Monitor data shows 49 percent of Texas suffering from some level of drought.
"The projects in Texas are a proving ground," said Zachary Dorsey, a spokesman for the WateReuse Association. "Throughout the Southwest, people are starting to look more and more at local reuse."
According to Dorsey, it's not unusual for communities in the U.S., including San Diego, to get their drinking water from essentially recycled water in big rivers such as the Colorado River, where by the time it reaches downstream there can be numerous wastewater plants that have discharged into the river. "Most everyone lives downstream from someone," said Dorsey. "And so the water does get reused. There are so many examples of that around the country."
San Diego gets approximately 85 percent of its water from the Colorado River and Northern California, and starting this fall it is scheduled to get a new desalination plant in Carlsbad that will meet about 7 percent of the county's needs. Additionally, the city of San Diego is looking to recycle wastewater.
San Diego is targeting an initial 15 million gallon per day water purification facility to be in operation by 2023—and there's a longer-term goal of producing up to 83 million gallons of purified water by 2035, or enough to supply one-third of the city's future drinking water supply. San Diego conducted a four-year demonstration project starting in 2009 and found it could produce water that met all federal and state drinking water standards.
What's more, the city also launched an outreach program to increase awareness of the toilet-to-tap water reuse and found public support rose from 26 percent in 2004 to 73 percent in 2012.
"Biggest barrier right now is the public perception piece of it," said Stanford's Choy, a former hydrologist with the U.S. Bureau of Land Management. "Eventually, once public perceptions have caught up with recycled water, that will be used for drinking water."