When you put your hand in a flowing stream, you touch the last that has gone before and the first of what is still to come.
—Leonardo da Vinci
In the twenty-first century, the nation is faced with a set of new conditions: the population continues to grow, the climate is warming, and demand for freshwater is surging, yet supplies are generally static or are dropping. Many experts fear that this century will prove to be an age of scarcity. We have responded by searching for new sources of water, which has led to innovations and forced the issues of water quality and quantity to converge more tightly than ever.
One effect of this new sensitivity to quantity has been a surge of research and investment in recycling. Just as severe water pollution in the Berkeley Pit led people in Butte, Montana, to create new remediation technologies, so has water scarcity led to technical invention. By 2010, more than a billion people worldwide lacked safe drinking water, and the demand for efficient water treatment systems was rapidly expanding: Global Water Intelligence magazine estimated the water treatment market will grow 18 percent between 2010 and 2016.
Perhaps no water treatment initiative is more counterintuitive, or divisive, than turning sewage—one of man’s most ancient and intractable water pollution problems—into a solution. Wastewater, of all things, is being hailed as a potentially significant source of “new” freshwater.
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Victorian London was the first place in which as many as 2.4 million humans were densely packed into a thirty-square-mile urban zone. In the last week of August 1854, many residents of Golden Square, a dank slum, suddenly became ill, and some of them died writhing in pain. Their symptoms included stomachaches, cramps, diarrhea, a terrible thirst, and vomiting. Seventy deaths occurred in twenty-four hours, most within five square blocks, while hundreds more—entire families, often—were infected by the mysterious disease. Known as cholera, the illness had been feared in Britain since devastating outbreaks in the 1830s and 1840s, one of which killed almost seventy-five hundred Londoners within two years. But no one knew how cholera was transmitted. Most experts suspected it was airborne, passing from one person to another by coughing or breathing.
John Snow, a private doctor, had a novel theory: he believed that cholera was transmitted by contaminated drinking water. He studied water samples under a microscope and plotted the patterns of cholera death on a map. His “Ghost Map” showed the disease radiating from an epicenter at the Broad Street pump, which drew from a well beneath Golden Square. Authorities shut down the pump, and within days the cholera epidemic disappeared.
In pinpointing the locus of the outbreak, Snow had pioneered the science of epidemiology. An assistant curate later discovered that the outbreak had been triggered when a sick baby’s diapers were thrown down the well, infecting the water. Shortly after Snow created his Ghost Map, an Italian researcher named Filippo Pacini identified the cholera bacteria itself, Vibrio cholerae, which circulates from one person’s feces to another person’s stomach, and back again. Although he published his findings, Pacini’s work was ignored until 1884.
From that point on, the elimination of human and animal waste from water supplies was one of the central goals of water treatment around the world, and one of the most important efforts in the history of public health. Yet today, much of our freshwater is mixed with treated sewage; some of it is used for irrigation, and some of it we drink.
A deeply embedded human trait is to be revolted by the idea of drinking sewage, and there are sound reasons for this. As John Snow discovered nearly two centuries ago, wastewater contains many contaminants that can lead to serious illness. But domestic sewage includes runoff from sinks, washing machines, and lawns; only 10 percent of household waste-water comes from the toilet, and most of that does not include solids. In other words, household effluent is about 99 percent water, which can safely and economically be recycled.
Although many people are not aware of this, water systems across the country take drinking water from rivers or lakes, then discharge treated wastewater back into those same water bodies; the water flows downstream, and at the next community the cycle is repeated; and so it goes, again and again. Up to half the water in American rivers is recycled this way.
At its northern reach, the Mississippi supplies drinking water to St. Paul, Minnesota, then carries the city’s effluent downstream. By the time it has traveled over a thousand miles south to New Orleans, the river has flowed through the “kidneys” of over a dozen cities before emptying into the Gulf of Mexico. Likewise, the Colorado River is used both for drinking water and to flush away treated sewage by more than two hundred communities, including Las Vegas, Phoenix, and Los Angeles.
The effluent in a river such as the Mississippi or Colorado doesn’t go directly into people’s taps, of course. Once it leaves a sewage plant, the treated sewage is swept along by river currents and is heavily diluted with clean, naturally supplied water. Sunlight, and time spent mixing and settling, degrade pollutants further. At the next town, treatment plants filter and disinfect the water to a high quality and often mix it with other supplies before piping it into people’s homes. To ensure quality, the EPA requires utilities to monitor pathogens and report any abnormalities, and most do so with admirable efficiency.
Though properly recycled water has proven safe for people to use, it doesn’t make sense to use water that has been laboriously and expensively cleaned to drinking water standards to fill toilets or irrigate gardens and golf courses.
In the 1960s, concerned about dwindling water supplies, hydrologists in arid states suggested using recycled water for those purposes. They separated treated water into two classes: water clean enough to drink, and “gray” water clean enough that it could be used for such things as irrigation. (Technically, gray water is household wastewater that does not contain sewage, while blackwater is wastewater that contains sewage. Both can be treated and reused.)
A gray water movement sprang up in dry and increasingly populated Southern California. Since 1994, the state has been a leader in developing large-scale treatment systems for oil refineries and communities. The seventeen thousand citizens of Arcata, for example, rely on a townwide gray water system for nondrinking use. Frustrated by California’s byzantine plumbing codes, “graywater guerrillas” have created illegal but efficient systems made of PVC pipes, buckets, gravel, and cattails that send sink and dishwasher runoff into toilets and lawns.
“In a drought-prone region like ours, it doesn’t make sense to use potable water to irrigate,” explained Michael Markus, general manager of the Orange County Water District (OCWD). Recycled water helps to conserve drinking water and reduce energy use.
Orange County lies south of Los Angeles and gets only fourteen inches of rain a year, on average. Though it once had plentiful groundwater, supplies began to drop in the 1950s. The depletion of aquifers—originally by irrigators, and recently by urbanization—has lessened the hydrostatic pressure underground. Ocean water has seeped as far as five miles inland to fill the void, and the salt water has contaminated freshwater supplies.
Two-thirds of the county still relies heavily on groundwater, but southern Orange County must import 90 percent of its drinking water from Northern California’s Sacramento Delta, or from the Colorado River, to the east. Both sources are hundreds of miles away and are already overused; importing their waters is expensive and energy-intensive.
In 1976, Orange County opened Water Factory 21 in Fountain Valley, the first treatment plant to use reverse osmosis to purify household wastewater to drinking-water standards. But it wasn’t used for drinking. It processed recycled sewer water into highly treated water that was injected into wells along the coast, forming a hydrologic barrier against saltwater intrusion.
In other places, recycled water has been used to make ice for skating rinks, or artificial snow, or to water the greens at golf courses such as Pebble Beach, home to the US Open. But that was just the beginning. For years, recycling advocates have pushed to use highly treated sewage (they prefer the term wastewater) as a new drinking supply. The technology is proven and is being used in a limited way. It has been highly controversial but may also be a harbinger of things to come for the rest of the nation. The question is, if current trends continue, will we have a choice?
How exactly do we turn human waste into drinking water? Praised as “showers to flowers” technology by its supporters, and derided as “toilet to tap” by its opponents, this transmutation process has set off a furor in California while slowly gaining acceptance elsewhere.
In El Paso, Texas, recycled water supplies 40 percent of the city’s tap water. In Fairfax, Virginia, recycled water provides 5 percent of the city’s drinking supplies. Counties in Florida and Georgia are evaluating the idea. In other parts of the world, the showers-to-flowers experiment is well under way. Windhoek, Namibia, for instance, is one of the driest places on earth and is the only major city to rely solely on treated waste-water for its drinking supply. Singapore uses ultrapurified sewage water to supply its high-tech industry. Arid nations such as India have already invested in advanced water treatment systems, while Israel and Australia are studying the idea closely.
By the mid-1990s, the Orange County Water District was facing continued problems with saltwater intrusion, increasing demand for its treated wastewater. County planners decided to replace Water Factory 21 with the larger, more advanced Groundwater Replenishment System, which produces 70 million gallons of highly treated wastewater per day, some of which is pumped into the aquifer and eventually added to Orange County’s drinking supply.
The practice remains highly controversial, but, said OCWD’s Markus, “We got into this out of necessity, not choice…. We live in a desert, but a lot of people here don’t seem to realize it. We have very little water, and the concern is that our periodic droughts will grow more extended. We realized we needed to find a more reliable supply.”
By 2007, the population of Orange County was surging toward 3 million and facing two related problems: soaring water demand and an increasing amount of sewage. In 2007, water consumption in the central and northern parts of the region was half a million acre-feet a year. By 2020, the population is projected to increase by 20 percent, and water consumption will climb to six hundred thousand acre-feet a year. (An acre-foot of water is 325,851 gallons, which is the amount that would cover an acre of land with one foot of water.) County managers solved their problems with one masterstroke: turn the bothersome sewage into a new supply of drinking water.
In January 2008, Orange County opened the $481 million Groundwater Replenishment System (GWRS), the world’s most ambitious sewage-water purification project, on the site of Water Factory 21. The GWRS collects wastewater from twenty-two cities—including Santa Ana, Newport Beach, Fullerton, and Costa Mesa—and, after an initial cleansing at a conventional two-stage sewage treatment plant next door, pushes the effluent through fine reverse-osmosis membranes, doses it with hydrogen peroxide (an oxidizer), and disinfects it under ultraviolet light to kill any microbes and pathogens. The result is “the cleanest water there is,” said Mike Markus of OCWD.
The GWRS’s treated water does not flow directly into people’s taps, though it is clean enough to do so. Instead, it is pumped fourteen miles north into a series of recharge basins in Anaheim. There, it mixes with natural supplies, storm-water runoff, and water diverted from the Santa Ana River, which eventually percolates down through layers of sand, clay, and rock into deep aquifers. Months later, the mixture is pumped back up and sent to 2.3 million customers.
The GWRS plant produces 23.5 billion gallons of water a year. “It’s a water supply we can’t get anywhere else,” said Markus. “It’s a big, big advance in water treatment.”
The toughest hurdle for reclaimed toilet-to-tap water is not microbial, financial, or technical: it is emotional. The “yuck factor” led to screaming headlines and became a divisive political issue, especially in San Diego and Los Angeles, the state’s two biggest cities.
“Your golden retriever may drink out of the toilet with no ill effects. But that doesn’t mean humans should do the same,” declared the San Diego Tribune. In 2006, the paper and the city’s mayor criticized the idea of adding recycled sewage to the city’s water supply as too costly and an unnecessary risk to public health.
Inveighing against the “toilet-to-tap boondoggle,” opponents labeled recycled sewage “an option of last resort” because “many uncertainties are associated with assessing the potential health risks of drinking reclaimed water.”
Daniel Okun, distinguished professor of environmental engineering at the University of North Carolina, told the New York Times Magazine that treated sewage water “may contain trace elements of contaminants. Reverse osmosis [filtering] and UV disinfection are very good, but there are still uncertainties.” Mary Quartiano, a spokeswoman for the Revolting Grandmas, a San Diego civic group, said she opposed the plan because “I just look at what goes down my toilet.”
San Diego imports about 85 percent of its water. In 1999, and again in 2007, the City Council promoted a $200 million sewage-reclamation project that would produce 21.2 million gallons of water a day. The city’s two relatively new treatment plants (which already transform wastewater into recycled water for irrigation and industrial use) work at only one-quarter of their capacity and could easily produce potable water. While the plan made sense on paper, public aversion to toilet-to-tap water overwhelmed the technical, fiscal, and environmental virtues of the initiative.
In 2007, when Bruce Henderson, a former city councilman, described water reclamation as a form of “economic racism” that “the affluent … can opt out of. They can just drink bottled water,” the initiative was killed.
In 2000, a similar public outcry forced Los Angeles to abandon a $55 million project that would have provided enough water for 120,000 homes.
But David Spath, who once headed the California health department’s drinking-water division, said that while some concerns about using reclaimed water are legitimate—treatment equipment can malfunction, for instance—the risks are “no greater, and probably in some cases better, than in what people may be drinking from river systems around the country.” Most California environmentalists, such as the San Diego Coast-keeper, support the initiative. City planners have noted that in the long run, toilet-to-tap water is going to be cheaper and have a smaller carbon footprint than pumping water from hundreds of miles away.
Orange County managed to avoid the yuck-factor trap by conducting extensive public outreach—“a battle for minds”—before proposing its enhanced reclaimed-water system on the grounds of Water Factory 21. The mission was led by Ron Wildermuth, a retired navy captain who had served as the public relations officer for General Norman Schwarzkopf during the first Persian Gulf War. After two years of handing out free pizza and talking to everyone from local garden clubs to leading politicians, OCWD had worn down virtually all opposition. With backing from city councils and state and federal politicians, Orange County’s GWRS was green-lit in 2001, winning $92 million in local, state, and federal grants.
The timing was fortuitous. Since the mid-1960s, the Metropolitan Water District (the Met), the regional water wholesaler, had supplied Orange County with sixty-five thousand acre-feet of water a year. But in 2007, water imports from the overstretched Colorado River and Sacramento Delta were severely restricted, and the Met was forced to drastically reduce the amount of water it could guarantee for delivery. Had Orange County not built the GWRS, which opened in 2008, it would have been left high and dry. (The Met has awarded GWRS an $85 million operational subsidy for reducing its dependence on imported water.)
The Groundwater Replenishment System is a collection of low-slung modernistic buildings, with tan concrete walls, big white holding tanks, and gray pipes. It uses a multistaged “treatment train” to produce “ultra-pure” water. First, sewage is processed by the county’s treatment plant, next door. (The residue left over from processing sewage is flushed out to sea, where it is diluted.) Then the treated wastewater passes into the GWRS, where microfiltration removes any bacteria, protozoans, and suspended solids; reverse osmosis removes viruses, dissolved minerals, and pharmaceuticals; any remaining microscopic organic compounds are removed by oxidation, which disinfects the water. Just about everything in the water is removed. Indeed, the GWRS’s water is so pure that minerals must be added back into it lest the treated water leach calcium out of the cement mortar that lines water pipes, weakening them.
The GWRS’s water is cleaner than natural water supplies. Even so, it is against state regulations to send treated wastewater directly into people’s taps (known as direct potable reuse). Why? There are technical reasons, but essentially, Markus sighed, because “the public is simply not ready yet.”
If current social and environmental trends continue, recycled sewage will undoubtedly be flowing directly into people’s taps within a few years—in Orange County, at least, if not in San Diego. “I believe it will become a reality in the not-too-distant future. Maybe ten years from now,” Markus predicted in 2009. “We hardly have enough water to keep up with the growth we have already. We’re severely challenged, and with all the new problems it’s only going to get worse.”
Markus was talking about Orange County, but his words hold true for every community. What might be called the Age of Easy Water—an era of plentiful, reliable supplies of clean water, accessible to population centers—is drawing to a close. The drama behind this headline is playing out in sometimes surprising ways and places, from deep beneath New York City to the high, parched valleys of Nevada to the fragile Sacramento Delta in California. People everywhere are facing a new hydrologic reality.