Waste Not: The Facts About Indirect Potable Reuse
By Parkinson, Jonathan
THE BOTTLED WATER I’m drinking tastes just like any other. It’s colorless and crystal dear, just like Evian or Aquafina. The only difference is the source: this bottled water came from a toilet in Singapore. In fact it’s recycled sewage, purified to drinking water quality by a process called indirect potable reuse (IPR), better known as “toilet-to-tap.” And while purifying sewage might sound like a radical idea, it’s not that much different from what we do already. Now an increasing number of local governments believe this technology gives us our best chance to solve a growing water shortage-if we can overcome our initial distaste. The Southeastern and Southwestern United States are now entering the second summer of a scorching drought, one so severe Georgia officials declared a state of emergency late last year. A nuclear reactor in Alabama had to shut down briefly last summer when cooling water ran low. Many parts of California experienced their driest year on record in 2007, while Lake Mead-the largest reservoir in the Western United States- is at 50 percent of capacity, and some estimates show it may run dry by 2021 if current trends continue. Other regions in the world have fared even worse, with large areas of Australia suffering through a crippling drought, and 400 of China’s 600 cities lacking adequate water supply for future growth. As Lester Brown outlined in the March/April Humanist (“Emerging Water Shortages”), the tripling of demand coupled with the effects of climate change account for the deficit. And if dry-weather conditions are more common now, many dimatologists believe they will only increase with climate change. In short, the world is headed into a future where clean water will no longer be something everyone can take for granted.
Though the problem is clear, there’s no agreement yet on how to solve it. In Georgia, officials have banned outdoor watering across the northern part of the state and are feuding with neighboring Tennessee and Florida over water rights. Last November, Georgia Governor Sonny Perdue even held a special prayer service on the capitol steps to pray for rain. Whether or not appealing to the heavens works, no one knows: but a handful of cities and counties in the United States and abroad aren’t waiting to find out; they’re trying something a little more practical first They’re turning to IPR.
Orange County, California was first; their “Water Factory 21″ began operation in 1976 and was just replaced by a new state-of-the- art facility that came online last November, purifying seventy million gallons of water a day. Singapore started using IPR in 2003. Fairfax County, Virginia; El Paso, Texas; and Namibia in Africa run small-scale programs as well. Each system operates a little differently, but the basic idea is the same. Treated sewage is pumped into a long microfilter shaped like a bundle of drinking straws with tiny holes that trap dirt and solids. From there, the sewage goes through reverse osmosis; built up to high pressure, it’s forced through hundreds of thick membranes with pores so microscopic nothing bigger than a water molecule can pass through. Even salts and dissolved chemicals are trapped, and the water that emerges is pure. As a final safety precaution, the filtered water is treated with hydrogen peroxide and run under ultraviolet light, like the light in a tanning booth, that will break down any organic compounds, just in case any ever did make it through. Once it completes its journey, the water is pumped into underground aquifers or into lakes or reservoirs so that it can eventually filter back into the drinking water supply.
There are a number of clear advantages to IPR. It drastically reduces demand for freshwater and opens up a drought-proof supply. It’s also much more efficient than other methods. Desalination uses roughly the same process but is about half as efficient; it takes two or more gallons of seawater to make the same amount of drinking water as IPR can make from a gallon of sewage. Finally, it can help cut down on the billions of gallons of partially treated sewage we pump into rivers and oceans each year, often carrying a toxic stew of chemicals and germs that turn up later in lakes, streams, rivers, and, ironically, even in tap water. Very often we end up recycling that discharged wastewater; in the Southwestern United States, for instance, tens of millions of people drink water from the Colorado River-the same Colorado River where towns and counties upstream dump their partially treated sewage. If anything, IPR is much safer, safe enough that Orange County has been able to recharge their groundwater supply using this process for over thirty years.
In spite of its potential, IPR has all too often been abandoned in reaction to the public’s distaste for the idea of drinking water that was once flushed down a toilet. Just south of Orange County, drought-parched San Diego imports 90 percent of its water. Several times over the years, local politicians have tried to implement an IPR system, only to meet defeat at the hands of opponents who took advantage of the unfortunate decision to market the method as “toilet-to-tap.” Back in 2006 the San Diego Union-Tribune opined, “Your golden retriever may drink out of the toilet with no ill effects. But that doesn’t mean that humans should do the same.” On a positive note, the San Diego city council recently voted to go ahead with a pilot project that would start next year, however, reclaiming wastewater with IPR has been proposed in Los Angeles; in DeKaIb County, Georgia; and in Tucson, Arizona, as well as in some cities and regions across Australia, typically with the same initial reaction: Recycling sewage? That sounds nasty. It can’t be safe. I don’t like it. Why can’t we do something else?
And so in the final analysis, it’s popular prejudice-not technical hurdles-that this technology needs to overcome before it can help us drought-proof our modern world. And the better voters understand how the system works, the more likely they are to accept it. Orange County provides the best example of how to market IPR effectively; before the new facility opened late last year, they offered free public tours on weekends and held public meetings, demonstrating the workings of the system to as many local residents as possible. Most of those who took the time to tour the plant were impressed, and the approach helped put an end to public opposition.
Together with education, a little more open-mindedness wouldn’t hurt. It’s no surprise that some of the same people who are willing to pray for rain don’t trust reverse osmosis. After all, the arguments against IPR are irrational ones based on instinct, not logic: it doesn’t sound right, so it can’t be. Never mind that we drink recycled sewage anyway; never mind that 2007 was California’s driest year on record; never mind that Lake Mead is at 50 percent of capacity and the level is still falling. If we don’t like some of the solutions, we can always ignore the problem-until the day comes when we go to turn on the tap and nothing comes out. At that point, the condemnation of local government for making us “drink from the toilet” doesn’t exactly hold water.
Our coming drought crisis need not be a crisis if we’re willing to consider dispassionately all the options we have. Applying logic and science rather than blind instinct, we can actually have an informed discussion on how best to solve our water problem, whether through desalination, better resource management, IPR, or, most likely of all, some combination of the three. Thanks to modern technology, it no longer much matters where the water comes from-we have the capability to make it pristine just the same.
Jonathan Parkinson is a science and technology writer who has most recently published an in-depth look at plans for magnetic levitating and other high-speed trains. He lives and works in San Diego, California.
Copyright American Humanist Association Jul/Aug 2008
(c) 2008 Humanist, The. Provided by ProQuest Information and Learning. All rights Reserved.