Pipe Dreams

The Urgent Global Quest to Transform the Toilet

Chelsea Wald

• Editorial: Avid Reader Press / Simon & Schuster
• Año: 2021
• ISBN:
  9781982116231
• Categoría: Scienze biologiche
• Categoría: Anatomia e fisiologia umana

Finalist for the 2022 NASW Science in Society Journalism Award
Longlisted for the 2022 AAAS/Subaru SB&F Prize for Excellence in Science Books From an award-winning science journalist, a "deeply researched, entertaining, and impassioned exploration of sanitation" ( Nature ) and the future of the toilet—for fans of popular science bestsellers by Mary Roach. Most of us do not give much thought to the centerpiece of our bathrooms, but the toilet is an unexpected paradox. On the one hand, it is a modern miracle: a ubiquitous fixture in a vast sanitation system that has helped add decades to the human life span by reducing disease. On the other hand, the toilet is also a tragic failure: less than half of the world's population can access a toilet that safely manages body waste, including many right here in the United States. And it is inefficient, squandering clean water as well as the nutrients, energy, and information contained in the stuff we flush away. While we see radical technological change in almost every other aspect of our lives, we remain stuck in a sanitation status quo—in part because the topic of toilets is taboo.Fortunately, there's hope—and Pipe Dreams daringly profiles the growing army of sewage-savvy scientists, engineers, philanthropists, entrepreneurs, and activists worldwide who are overcoming their aversions and focusing their formidable skills on making toilets accessible and healthier for all.This potential revolution in sanitation has many benefits, including reducing inequalities, mitigating climate change and water scarcity, improving agriculture, and optimizing health. Author Chelsea Wald takes us on a wild world tour from a compost toilet project in Haiti, to a plant in the Netherlands that salvages used toilet paper from sewage, and shows us a toilet seat that can watch users' poop for signs of illness, among many other fascinating developments."Toilet humor is one thing, but toilet fact, as digested by skilled science writer Wald, is quite another…[ Pipe Dreams is] a highly informative, well-reasoned call to rethink the throne" ( Kirkus Reviews ).

The New Toilet Revolution

Are you ready?

To keepe your houses sweete, clense privie vaultes.

To keepe your soules as sweete, mend privie faults.

—Sir John Harington, A New Discourse of a Stale Subject, Called the Metamorphosis of Ajax (1596)

Getting to Loo-topia

I’ve come to the north of the Netherlands, to a medieval town called Sneek, population thirty-three thousand, whose name is pronounced with a hard a, like the tubular animal that tempted Eve with an apple, and not with a hard e, like the act of slinking around. An imposing seventeenth-century city gate, called the Watergate, sits astride one of the town’s many canals, and, in the summer, major regattas take over a nearby large lake, called the Sneekermeer.

But Sneek has a lesser-known tourist route, one for people like me, who are interested in the unsavory side of water. In 2004, a company called DeSaH (the Dutch acronym for Decentralized Treatment and Reuse) installed vacuum toilets, not unlike those you might have used on airplanes or trains, in a thirty-two-house complex. It treated the waste from those toilets in one garage instead of sending it through the sewers to a centralized treatment plant. The successor project, called Waterschoon (schoon means “clean” in Dutch), serves more than two hundred apartments. The now-king Willem-Alexander of the Netherlands himself came to open it in 2011 when he was still known as the Water Prince for his advocacy regarding all things Dutch and watery.

These “New Sanitation” projects are just a tiny corner of a new, global toilet revolution—a growing movement that has the goal of upending the way we manage our most basic bodily functions. The toilet we have today was born in England during the nineteenth-century Victorian sanitary revolution. It was a modern miracle: the ubiquitous user interface of a vast, reliable system of pipes, sewers, and, later, treatment plants that was both extraordinarily convenient and medically essential, stopping outbreaks of devastating diseases such as cholera and typhoid fever and giving countless people longer, more productive lives. In 2007, the readers of the British Medical Journal named the sanitary revolution “the most important medical milestone since 1840,” putting it ahead of antibiotics, anesthesia, and vaccines. In 2013, the Economist featured a flush toilet on its cover, with Rodin’s The Thinker sitting on it, wondering, “Will we ever invent anything this useful again?”

But our toilets no longer look quite so miraculous as they once did. While our societies have changed dramatically over the past century, we have allowed our toilet systems to stagnate. Today, they are inadequate to the challenges ahead of them. Our cities are growing, overwhelming their aging, inflexible infrastructures, especially during shocks such as storms. We’re throwing more and more junk into the system, from trash to oil to pharmaceuticals to toxic chemicals. And resources are growing ever scarcer, making the squandering of the water, nutrients, energy, and other components in wastewater harder to stomach. American inventor and visionary R. Buckminster Fuller could have been talking about the toilet when he wrote in 1970 that “pollution is nothing but the resources we are not harvesting. We allow them to disperse because we’ve been ignorant of their value.”

On top of that, despite some progress toilets fail to reach so many. According to the latest numbers from 2017, some 2 billion people still lack a minimally adequate toilet and hundreds of millions don’t use a toilet at all. Most of these are in low- and middle-income countries, where toilet systems fail to serve both rural and urban areas. Many cities are growing much faster than infrastructure can keep up with, and they can get so crammed in parts that there’s no room for private toilets. Sometimes sewage flows through open trenches instead of closed pipes. And people may resort to using “flying toilets”—poop-filled plastic bags that they discard in streets or ditches, or just fling away.

You might be surprised by other places that don’t have decent toilets. According to one report on the state of water and sanitation in the United States, “It is safe to say that more than two million Americans live without complete plumbing” and “even that may be an underestimation.” Accurate numbers aren’t available in part because, in 2016, the U.S. Census Bureau’s American Community Survey eliminated its question about toilet access. Lack of safe sanitation, as environmental health activist Catherine Coleman Flowers puts it, is “America’s dirty secret.”

Some people in the Black Belt region of the South, where Flowers hails from, unable to buy or maintain septic tanks specialized for the clay soil, “straight pipe” their wastewater just a few feet from their homes, into yards where children sometimes play. Researchers found that two in five study participants from one of these poor areas in Alabama had intestinal parasites, particularly hookworm, which today are mostly associated with low-income countries. In some rural Alaskan communities, where the ground isn’t suitable for wells or septic systems, thousands of people defecate into euphemistically named “honey buckets,” which they then empty by hand into very unsexy “lagoons.” In those communities, gastrointestinal, respiratory, and skin infections are rampant. In Hawaii, eighty-eight thousand mostly unlined cesspools—little more than holes in the ground—accept wastewater from toilets and other household plumbing, which then leaches out and contaminates local streams, groundwater, and the ocean with pathogens. And just a few years ago, San Diego’s homeless community, then the fourth largest in the United States, fell victim to a hepatitis A outbreak, which sickened 592 people and killed 20, in part due to conditions such as insufficient toilets and handwashing facilities in the encampments.

Around the world, the toilet has become a paradox. Lauded as a savior of civilization, it also exacerbates many of the world’s problems: inequality, disease, pollution, climate change, water shortages, soil degradation, waste. It’s time, many think, to escape the old paradigms and harness toilet systems not only to sequester poop but also to do a variety of other desirable tasks, such as guarantee everyone a place to go, watch for disease outbreaks, make fertilizer and fuel, manufacture components for bioplastics and asphalt, synthesize drugs, produce clean water, and build job-creating businesses. Bill Gates, the computer pioneer turned mega-philanthropist and toilet enthusiast, delivered a widely seen speech about “radically new… alternatives for collecting, managing, and treating human waste,” while he was wearing a suit and holding a beaker of shit (his own, one hopes—or doesn’t?). The focus of the Bill and Melinda Gates Foundation is on the world’s poor, but the revolution is needed everywhere, poor or rich, cold or hot, sewered or not.

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New Sanitation in Sneek is just one attempt to step away from conventional toilet systems, but it’s a good introduction to the revolution because it is a sort of photo negative of those. Instead of diluting poop and pee with water, it concentrates them; instead of handling poop and pee centrally, it does it locally; instead of primarily using resources to treat poop and pee, it makes resources out of them.

The process begins with the vacuum toilets. I try one out at the company’s small headquarters in an industrial park. For research purposes, they have installed the newest generation there, but only into their men’s room. I want—and fortunately also have a need—to use them, so my host, Moniek Agricola, the young engineer who takes care of much of DeSaH’s day-to-day maintenance, stands guard outside. They’re not like the metal toilets you’d see in an airplane but are instead fashionably white and curvy, with blue glowing buttons for flushing. There’s only a tiny amount of water in the bowl, which serves mainly as a security blanket for users. I sit down and make my offering. When I press the button, a hole at the bottom opens and the void, generated by a pump, sucks everything down with a whoosh! that is gentler than that on an airplane, even if I leave the lid open (which I’m not supposed to do).

In this damp region, the point of the extremely low-flow fixtures isn’t primarily water conservation, although a recent drought shocked the Dutch into rethinking their trust in the never-ending abundance of water. New Sanitation bases its treatment process on microbe-powered anaerobic digestion, which benefits from the vacuum toilets’ concentrated waste, rather than the aerobic digestion that forms the basis of conventional wastewater treatment. As you might know from your workouts, aerobic processes demand oxygen, and anaerobic ones don’t. Anaerobic digesters for sewage can save energy because they don’t have to pump air to the microbes that do the work. They also take up less space and leave less residue behind.

They have other benefits, too, as I see when Agricola takes me to the Waterschoon site, in a quiet complex that’s built of red bricks, solid and low to the ground, with some medieval-style arches for flair. The residents, who must qualify for government housing subsidies to live here, display knickknacks and grow plants in large windows. Pipes carry the toilet waste, known as “black water,” from about two hundred apartments to a treatment building at the center of the complex. Entering, I hear the loud hiss of machinery and my nose registers the sharpness of ammonia layered over an earthy richness. In a corner, the black water flows upward through a two-story black metal cylinder containing a blanket of microbes. These microbes, like the ones that thrive in lake sediments and the stomachs of cows, need little to no oxygen to live. As they munch on the waste, they produce biogas, which flows in short puffs to a boiler that heats water for the complex, replacing some of the natural gas that the Netherlands plans to phase out in the coming years because extracting it has caused a series of small but damaging earthquakes. The little solid matter they leave in their wake empties from a hole in the bottom when it gets to be too much. In a way, the digester is like an artificial stomach, burping and pooping.

The digester also produces a liquid, which then enters two more reactors that deal with the nitrogen and phosphorus compounds in it. British anthropologist Mary Douglas famously described dirt as “matter out of place,” and so it is with these nutrients: they can be either pernicious polluters or essential fertilizers, depending on where people choose to put them. If released from wastewater treatment plants indiscriminately, these nutrients can lead to overgrowth of algae in waterways, suffocating the other forms of life in there. But at Waterschoon, the first reactor uses specialized microbes to pull out nitrogen, which is bound up in the compound ammonium, turning it into a gas and releasing it into the atmosphere, which is already 78 percent nitrogen. In the second, a chemical reaction binds the phosphorus into a mineral called struvite, which emerges from the reactor as small, smooth stones that can be used as a fertilizer.

The system also treats toilets as part of a larger cycle of water and waste. The Waterschoon housing units come with in-sink food grinders (what many Americans call by the product names Disposall or InSinkErator but tend to be banned in Europe), which also feed into the anaerobic reactor, providing the microbes with additional nourishment. And the homes’ shower, sink, dish- and clothes-washing water—“gray water”—flows through a different set of pipes to join the liquid from the black water process for a final set of cleaning steps. That gray water is relatively hot, so the facility also uses a heat exchanger to transfer some of the energy to the water used for heating the homes. Ultimately, DeSaH would like to clean the water further and cycle it back into the houses for toilet flushing and other uses—even possibly for drinking—but for now the system discharges it into the sewer.

Biogas, fertilizer, heat, and water savings in a modular, flexible system. Who wouldn’t want toilets like these? Later, when I pose that question in a meeting with project collaborators from the company, the municipality, and the water board at DeSaH’s headquarters, I learn that this concept has been a harder sell than you might think. Sneek has hosted a parade of interested delegations from around the world—as far as China—but almost never do visitors go home and install New Sanitation. Faced with financial, regulatory, and cultural headwinds, says Flip Kwant, DeSaH’s commercial director, “they never came back.” It was even a hard sell in the Netherlands: before Sneek, two other new housing developments in different Dutch cities considered but ultimately refused the opportunity to pilot the system. Wouldn’t the vacuum toilets be too loud, too smelly, too embarrassing? people wondered. For a sanitation engineer, or even a designer or sociologist or businessperson or economist or philanthropist, to be part of the revolution already takes a certain fortitude, since they must cope with disgusting materials, limited funding opportunities, risk of acute and chronic disease, and terrible poop jokes. Unlike with computers and smartphones, most people don’t want to be early adopters of new toilet technologies. They just want reliable toilets that work.

But Sneek was special. It wanted to bolster its reputation as a “Water City,” the housing developers thought it would give the new project cachet, and DeSaH’s presence in the community built trust. What’s more, the locals have grit: the day I’m there, a major windstorm blows through, putting the nation (and me) on high alert, but the seafaring people in this region are used to much worse. They’ve just pulled their boats up onto shore and gotten on with life. So it doesn’t surprise me that Waterschoon has drawn few complaints and that one neighbor in the original thirty-two-house project, when researchers questioned him about his openness to participating, just said, Why not? “They have to experiment somewhere.”

Yes, they do—and they will, as the worldwide movement generates a motley mix of concepts for the future of toilets. The story of the toilet revolution is not just a tech story: it’s a culture story; it’s a people story. And, even if you don’t work in toilets yourself, in the coming years the revolution may ask something of you. To pee and poop in separate holes. To compost your toilet waste and spread it in your garden. To cook with gases extracted from a septic system. To eat off paper plates made from recycled used toilet paper. To talk to your toilet about your health. To drink cleaned-up toilet water. To talk to your friends—and strangers—about your toilet. Are you ready? Are you willing? I’ve given a name to the future that the toilet revolutionaries are striving to bring about: Loo-topia. Eden had just one snake, but to get to Loo-topia, the world is going to need a whole lot of Sneeks.

What’s in the Toilet?

Tinkle, plop, kawoosh! But wait, before you walk out of the bathroom and go on with your life, what exactly was it that you just flushed away? Let’s start with poop and pee. These are the major ways your body rids itself of the stuff it doesn’t want or no longer needs. There’s considerable variation in what people produce. According to a paper from researchers at Cranfield University in the United Kingdom that reviewed the published research on the topic, people expel about four and a half ounces of poop per day—that’s almost the weight of three golf balls. But some people poop a lot more: one healthy subject pooped out a whopping twenty-eight ounces per day, which is more than the weight of seventeen golf balls. Another healthy subject, on the other hand, produced less than two ounces per day, which is just about one golf ball. Most people pass all of their daily poop at one sitting—a hole in one, you might say—though it’s not unusual to do it more than once per day or once every other day.

So what accounts for these differences in volume? Let’s break poop down to find out. The biggest fraction of shit is actually water. A healthy poop is about three-quarters H₂O. That water keeps the matter flowing through your intestines. Should you excrete too little water, you have constipation; too much and you have, of course, diarrhea. The daily quantity of poop of people hospitalized with diarrhea weighs some five times the average.

If you take all of that water out and analyze the remaining dried-out poop, about a quarter to a half consists of bacteria, some of it dead and some of it still alive. For the most part, these bacteria are your friends; they live in your digestive system and help to extract energy from your food, support your immune responses, and even strengthen the integrity of your gut. Amazingly, according to some estimates, there are perhaps more than a hundred trillion microorganisms—bacteria, as well as other types called archaea and single-celled fungi—in the human gastrointestinal tract, making the colon one of the most densely populated and biologically diverse microbial habitats on earth. Some scientists refer to the combination of you and your bacterial microbiota as a “superorganism.” But since this community of microbes keeps changing and renewing itself, your body must constantly rid itself of its members—and that’s why they come out with your poop.

A small number of the microorganisms in your poop are emphatically not your friends, however. People infected with norovirus can shed more than a trillion copies of the virus in just one gram of feces (about the size of a peanut). You need only ingest a small amount of a sick person’s poop to get infected with whatever viruses, bacteria, or parasites are in there. To be successful, toilet technologies must eliminate that threat.

Most of the rest of the non-water fraction is undigested food, the proportion of which depends heavily on diet, including hard-to-digest carbohydrates such as dietary fiber (about a quarter), some nitrogen-containing substances such as protein (up to about a quarter), and fats (up to about a sixth), for which your body doesn’t have use. Dietary fiber—which, chemically speaking, consists of long chains of sugar molecules—is particularly significant: although fiber is hard for your body to break down, it is nonetheless important for healthy digestion (what grandmothers everywhere refer to as being “regular” and why they eat their bran). The size and weight of your poop, as well as the rest of its composition, depend a lot on how much fiber you consume, not only because of the fiber itself but also because it carries water with it. More fiber equals more water equals bigger poops. Because people who live in low-income countries tend to have more fiber in their diets, their poop weighs on average abo...