Skip to main content

The Other Dark Matter

The Science and Business of Turning Waste into Wealth and Health

Grossly ambitious and rooted in scientific scholarship, The Other Dark Matter shows how human excrement can be a life-saving, money-making resource—if we make better use of it.

The average person produces about four hundred pounds of excrement a year. More than seven billion people live on this planet. Holy crap!

Because of the diseases it spreads, we have learned to distance ourselves from our waste, but the long line of engineering marvels we’ve created to do so—from Roman sewage systems and medieval latrines to the immense, computerized treatment plants we use today—has also done considerable damage to the earth’s ecology. Now scientists tell us: we’ve been wasting our waste. When recycled correctly, this resource, cheap and widely available, can be converted into a sustainable energy source, act as an organic fertilizer, provide effective medicinal therapy for antibiotic-resistant bacterial infection, and much more.

In clear and engaging prose that draws on her extensive research and interviews, Lina Zeldovich documents the massive redistribution of nutrients and sanitation inequities across the globe. She profiles the pioneers of poop upcycling, from startups in African villages to innovators in American cities that convert sewage into fertilizer, biogas, crude oil, and even life-saving medicine. She breaks taboos surrounding sewage disposal and shows how hygienic waste repurposing can help battle climate change, reduce acid rain, and eliminate toxic algal blooms. Ultimately, she implores us to use our innate organic power for the greater good. Don’t just sit there and let it go to waste.

264 pages | 8 halftones | 6 x 9 | © 2021

Economics and Business: Economics--Agriculture and Natural Resources

History of Science



"A take on waste that's anything but wasteful—it's a fascinating dig into the history and science of handling human excrement. . . . Equally remarkable are Zeldovich's sections on the development and evolution of wastewater treatment plants. . . . Zeldovich is at home with an awkward subject, making for a grossly engrossing and vivid survey. Readers won't take the 'flush and forget' mindset for granted again."

Publishers Weekly

"Zeldovich is an engaging writer. She loves puns and poop jokes. (Who doesn't?) And her travels around the world are, in their own scatological way, inspiring."

Elizabeth Kolbert | New York Review of Books

"[An] original, necessary book."


"It would be easy for a book that focuses on obstacles to improving global sanitation, fixing the agricultural waste cycle, reducing pollution, and improving health to resort to paralyzing gloom. The Other Dark Matter does not shy from the enormity of the problems, yet suggests solutions are achievable, at scales from individuals to entire countries. Paced quickly with prose enlivened by the author's on-location reporting and personal experiences, the book is far from a grim slog through the world's sewers—it's more like an exciting tour in a biogas-powered balloon."


"The Other Dark Matter does not shy from the enormity of the problems, yet suggests solutions are achievable, at scales from individuals to entire countries. Paced quickly with prose enlivened by the author's on-location reporting and personal experiences, the book is far from a grim slog through the world's sewers — it's more like an exciting tour in a biogas-powered balloon."


"It's unusual to come across a book that makes you say, 'Oh, crap!' in a good way."

American Scientist

“In bright and airy prose, she takes readers on a globe-spanning trip to sites where fecal material is reprocessed and figuratively turned into gold. . . . Readers should leave this book with a renewed interest in sustainable systems to manage what we normally put out of sight and out of mind."

Natural History

“It is unquestionably [a topic] that—given the ever-increasing human population belaboring the planet—merits our attention if we are, ecologically and sustainably speaking, to prevent finding ourselves collectively up a famous creek without a propulsion device. Ms. Zeldovich’s new book looks to be an excellent way to introduce ourselves to it.”

The Well-Read Naturalist

"Given the growing scale of public engagement in sanitation, there is a glut of books on the subject. Not all of them are readable, not all of them are well researched. This one is. It takes the technology questions further. It is an engaging read on a queasy topic"


"In writing a primer on poop and its possibilities, [Zeldovich] performs a much larger function: destigmatizing a vital biological product that has long gotten a bum rap."

Columbia Magazine

"Some of the ideas in [the book] really feel like they could change the world in a major way. . . . It's really excellent."

Across the Margin

"Even readers familiar with the history and ecology of waste management will not be disappointed. . . . As detailed as it is witty. . . . Given the growing scale of public engagement in sanitation, there is a glut of books on the subject. Not all of them are readable, not all of them are well researched. This one is. It takes the technology questions further. It is an engaging read on a queasy topic."


"This is some good shit, people. Not only entertaining, but deeply important. Everyone with a colon should read this book. Centuries back, people knew the value of shit. In countries with poor soil, human waste was like gold: people stole it, paid their rent with it, and gave it as gifts. Today, keeping it out of our waterways is our best hope for defusing what Zeldovich calls the Great Sewage Time Bomb. She is an ideal guide to this ridiculously fascinating world."

Mary Roach, author of Stiff: The Curious Lives of Human Cadavers

"Zeldovich shows to dazzling effect how a famously difficult subject—the often peculiar scientific history of human waste—can become an engrossing tale. The story is enlightening, surprising, occasionally enraging—and wholly worth your time."

Deborah Blum, Pulitzer Prize–winning author of The Poison Squad

"Zeldovich shows that excrement can be useful, profitable, and anything but waste, and does this with warmth, curiosity, and humor. This book is a great companion should you wish to journey to the rich and still underexposed world of shit (and you should)."

Rose George, author of The Big Necessity: The Unmentionable World of Human Waste and Why It Matters

"Here is an indispensable book about what we might call the Anthro-poo-cene. Humanity's current collision course with nature has everything to do with energy and how we abuse it—including the human waste products of our metabolic bodies. This lively and entertaining history is also full of innovative ways people are finally dealing with their you-know-what."

Mary Ellen Hannibal, author of Citizen Scientist: Searching for Heroes and Hope in an Age of Extinction

"Who knew our poop could be so fascinating and important? In her brilliantly reported and written new book, Zeldovich shows that now more than ever the health of humanity and the rest of nature depends on how we handle 'the other dark matter.'"

John Horgan, author of Pay Attention: Sex, Death, and Science

"An intriguing, compelling, very human story of how a valuable resource has been used and squandered, thrown away, and rediscovered. It is a story of the people who, against a background of mockery and disbelief, have developed creative, lucrative, and ecologically viable options for reframing what many have seen as a 'problem' of 'waste disposal' into an opportunity for innovative resource use. It will have wide appeal to all intelligent readers, both within and well beyond academia."

David Waltner-Toews, author of The Origin of Feces: What Excrement Tells Us About Evolution, Ecology, and a Sustainable Society

Table of Contents

Part 1: The History of Human Waste

Chapter 1: How I Learned to Love the Excrement
Chapter 2: The Early History of Human Excreta
Chapter 3: Treasure Night Soil as if It Were Gold!
Chapter 4: The Water Closet Dilemma and the Sewage Farm Paradigm
Chapter 5: Germs, Fertilizer, and the Poop Police

Part 2: The Present: A Sludge Revolution in Progress

Chapter 6: The Great Sewage Time Bomb and the Redistribution of Nutrients on the Planet
Chapter 7: Loowatt, a Loo That Turns Waste into Watts
Chapter 8: The Crap That Cooks Your Dinner and Container-Based Sanitation
Chapter 9: HomeBiogas: Your Personal Digester in a Box
Chapter 10: Made in New York
Chapter 11: Lystek, the Home of Sewage Smoothies
Chapter 12: How DC Water Makes Biosolids BLOOM
Chapter 13: From Biosolids to Biofuels

Part 3: The Future of Medicine and Other Things

Chapter 14: Poop: The Best (and Cheapest) Medicine
Chapter 15: Looking where the Sun Doesn’t Shine
Chapter 16: From the Kindness of One’s Gut: An Insider Look into Stool Banks
Afterword: Breathing Poetry into Poop



Every fall, my grandfather would set off to do two things: prepare our small family farm for the long Russian winter and empty out our septic system.
He would don his sturdy overalls and heavy-duty gloves, both gray as the rainy sky above, tie two old beat-up buckets to long, thick ropes, and head out to the sewer tank buried by the fence surrounding our property. As he opened the pit, ringed with garden weeds and stinging nettles, the stink slowly wafted through the air, settling over our land like a small stomach-turning cloud. Yet my nose would get used to it, and soon I wouldn’t be bothered by it at all. I even wanted to help, but my grandmother wouldn’t let me go near the pit— she was afraid I’d fall in.

Today’s septic tanks can last for years without being emptied, but ours would fill up much more quickly. We could have called a service to empty it, but my grandfather wouldn’t let all those riches go to waste. He had a system...

He poked small holes in the strawberry and tomato patches, where the plants were already shriveled, expecting winter— and poured the goo into them, deep into the earth. He dug little trenches around the apple trees and emptied his buckets onto their roots. And he also dumped a bunch into one of the compost pits, adding it to the already accumulated dead plants, leaves, and our kitchen food scraps. The compost pits operated on a rotating schedule. At the end of the season, he’d close up the current one for a couple of years, leaving it to ferment and bio-degrade. When he opened it again two seasons later, after the snow melted and planting time arrived, all the original biomass was gone. The pit was full of soft, black dirt teeming with fat, lazy earthworms that crawled around slowly, too heavy from gobbling down all that food. The sewage odor was gone, too. Instead, the pit smelled of rich, fertile soil, nature, spring, and the promise of the next harvest. And it made me hungry because I thought of all the food we were going to grow with it...

Today, we may call it organic farming, composting, recycling, or the circular economy. But for him it was, simply, the way of life...

The Russian equivalent of the word “fertilizer” is udobrenie, which comes from the word dobró, meaning “good” and “rich.” Udobrenie meant returning all that good stuff  to the earth. Even the common Russian colloquialisms that revolve around the toilet recognize that. When toddlers were being potty trained, we jokingly referred to the moment they had to go as giving out dobró or bogatstvo— “the  riches.” I think that’s why I never viewed sewage as waste. I always considered it more of a treasure than a nuisance. If we didn’t return it to the earth, the earth wouldn’t have the stamina to feed us.

I knew that other people, who lived in big apartment buildings, didn’t have septic tanks, but as a child I assumed that their sewage was also somehow returned to the earth...

I soon learned otherwise.

The land we lived on wasn’t entirely ours. My grandfather received the parcel from the Russian airplane factory where he worked as an engineer during World War II...

Thirty years after the airplane factory gave the parcel to my grand-father, the city had grown— and so had the demand for land. The factory took the land back to build apartment buildings to house more workers, who would build more jets. Our village fought back— and lost. The factory moved the displaced families into apartment buildings, demolished their houses, and bulldozed their plots. When the bulldozers roared in, squashing our vegetable patches under their massive steel tracks on a gray autumn day, the sky dropped little beads of water onto us, as if mourning our farm. I wished I could cry with it, but I had no tears left. I just watched our apple trees falling to those angry metal machines like tin soldiers. When they finished, the bulldozers scraped off the rich black topsoil that my grandfather had spent 30 years cultivating and trucked it away to the summer homes of the ruling elite. They wanted not just our land, but our dirt, too. They knew that black dirt was gold. It was black gold.

Our new apartments had flushing toilets and hot water, but did little to help us heal. We grieved for our farm. A month after we moved, I was struck with a rare disorder that gradually took my ability to stand straight and walk. I lay in bed, homeschooled by my parents, slowly losing feelings in my legs. My grandfather’s legs failed him, too, albeit in a different way— he developed bone cancer. We both collapsed like our apple trees, as if someone had pulled our roots from the rich soil that fed us...

A few years later, when my family moved to the United States and settled in New York City, I learned quickly that most people did not know where their sewage went. And they had no desire to know, either. They were quite happy to flush and forget. For a long time, Western society believed this was the way to go. Governments and private companies built big sewage plants with the goal of rendering the matter harmless, but not necessarily reusing it. We destroyed the organic goodness we produced, and we forged synthetic fertilizers to grow our crops. And at the same time, the developing countries kept struggling with disease outbreaks and other sanitation issues stemming from fecal contamination of drinking water. It seemed that neither world could get its shit right. Mother Nature’s link was clearly broken. 

And then, in the past decade, I saw the sewage tide turning back. The cultural taboos shrouding toilet habits, human waste, and sewage disposal began to thin. People became interested in what happened after they flushed. The discussions about recycling various kinds of waste pivoted to excrement. We began to talk about recycling poop. Sanitation engineers began to describe wastewater treatment processes as resource recovery activities. Epidemiologists worldwide used sewage to track disease outbreaks.

In 2011, the Bill and Melinda Gates Foundation issued its Reinvent the Toilet Challenge, asking the world’s brightest minds to redesign our privies to recover valuable resources from our waste, including energy, nutrients, and clean water, and to operate autonomously without connections to sewage treatment plants. Scientists and engineers talked about the value of the circular economy that favored the concept of giving back to the earth. Brave and brilliant startups sprouted all over the world, devising new ways to turn waste into wealth. Environmentalists, entrepreneurs, and organic farmers gradually began to see their excrement as dobró and bogatstvo...

It was as if the world embraced the wisdom that my grandfather followed 70 years ago, when he first built his farm. And that was very exciting. Because once we restore the broken link, we will use less fossil fuel, waste less energy, generate less acid rain, and produce fewer greenhouse gas emissions, fewer bleached corals, and fewer dead fish. Instead, we will clear algal blooms from our waters, slow down global warming, and grow healthier food with the fully organic goodness that we ourselves have produced.

Be the first to know

Get the latest updates on new releases, special offers, and media highlights when you subscribe to our email lists!

Sign up here for updates about the Press