On This Earth

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Profile: Behind the scenes of the podcast Liquid Gold
Kerry Tozer and Jordan Roods were new doctoral researchers at the University of Technology Sydney (UTS) when Kerry saw an ad for a competition posted by the university’s podcast studio. The prize was featuring the winner’s research. Wouldn’t it be cool if their work were turned into a podcast? They entered.

“We were very surprised when we actually won,” says Kerry, “because it was a university-wide competition for both students and staff.” Although they were in the early days of their research, they worked with producers at UTS Impact Studios to create All That We Touch: Liquid Gold, a sound-rich podcast that takes listeners on a journey from Australia to other continents, unpacking the looming nitrogen and phosphorus crises. It showcases how nutrients in human urine can be recycled to revolutionize the way we grow our food and care for our ecosystems.

In the studio, producing All That We Touch: Liquid Gold. Clockwise from left: Kerry, Jordan, Associate Professor Dana Cordell, and Producer Britta Jorgensen. Courtesy of UTS Impact Studios.

Nice work!

Kerry and Jordan are social scientists at the Institute for Sustainable Futures (ISF), UTS. Their doctoral research is part of a broader public-private collaborative called the Nutrients in a Circular Economy Research Hub (NiCE Hub). Funded by the Australian Research Council, NiCE Hub connects researchers across seven Australian universities with water utilities, government, industries and international organizations, like the Vermont-based Rich Earth Institute. Scientists at NiCE Hub study ways to collect and recycle nutrients from urine to develop safe and effective renewable fertilizers.

In the podcast, listeners learn that UTS is the first university in Australia to have a building with a urine diversion system. After the urine from its toilets is transported and stored, it is pumped through a membrane bioreactor, resulting in a commercial-grade liquid fertilizer that can be applied to garden plants and farm crops.

Bottoms Up! Professors Stuart White and Jason Prior join Kerry and Jordan in celebrating golden vials of liquid gold, destined to become a clear urine-based fertilizer developed at NiCE Hub. Courtesy of UTS Impact Studios.

“It’s such an interesting and fun topic,” says Jordan, “and I think everyone who listens to the podcast positions themselves in that system — giving something from your body to grow the food to feed the population.”

A diverse duo

Jordan grew up by the coast in Sydney. He studied social and political sciences and law at UTS before pivoting to work on ways to “close the loop between the bathroom and food system,” as he describes it. He’s interested in how the circular economy could be more effectively governed through new rules, like laws, zoning and plumbing codes (“basically all that boring stuff,” he jokes), as well as partnerships and community education. Jordan aims to improve outcomes for people and our planet by shifting our value systems, but doing so requires a high level of coordination among those who haven’t had exclusive responsibility for nutrient recycling.

For now, he and others within the NiCE Hub see the most potential to grow food in hydroponic settings, where regulations for using urine-based fertilizers are less stringent than for land-based agriculture.

Before joining ISF/UTS, Kerry focused on a different type of sustainability in her former career: managing corporate supply chains. Now she’s working on ways to scale up the circular supply chain — both the people and the economic systems — all while encouraging the recovery of nutrients. She wants to focus on the customer and create an economy around urine recycling, moving beyond simply donating pee, she says.

“We need something that’s going to be easy and convenient, and not require a lot of handling,” Kerry explains. What people see when contributing urine should look like a normal ceramic toilet or urinal; that way, people are much more likely to use it.

For Jordan, it’s important to understand what people using the system think. To get feedback, he and Kerry added a survey to the podcast.

In their wildest dreams…

What would be their idea of a successful circular nutrient economy in the future?

Kerry imagines new housing being designed with separate plumbing to collect urine. The urine-derived fertilizer could be used by struggling farmers or applied to cricket playing fields and other green spaces. She would like strong community awareness programs that create some hype and get people involved.

Jordan is keen to start larger projects, like the one in Cape Town, South Africa, where huge amounts of urine are collected from urinals in the DHL Stadium. “I would be interested in trying that in Australia,” he says, partly because it would save water, but also because it represents more equitable sanitation. “I think we’re at a point in history,” he adds, “where we can’t continue to do business as usual. We’re seeing that play out everywhere — these linear approaches to growing our food, dealing with our waste; it’s just not tenable anymore. Urine offers us a way to close that loop.”

And if we don’t? “We continue to waste resources, waste nutrients,” says Kerry. “We continue to be disassociated from our own bodily functions. We just get further and further away from what connects us to the world.”

Kerry was influenced during her youth by frequent visits to the Blue Mountains National Park near Sydney, and says, “I have this really deep love of nature, and I hate seeing the pollution and destruction. I think there are a lot more regenerative ways we can still have a civilized urban life that don’t impact on our beautiful natural environment.”

Want more?
- Listen to Kerry and Jordan speak as part of a panel on story-telling at the virtual Rich Earth Summit, November 4, 10:30-11:30 a.m. Eastern US time.
- Respond to their survey about whether their podcast influences public awareness, perceptions, and willingness to engage with peecycling.
- Check out the two bonus episodes of All That We Touch: Liquid Gold.
  - Liquid Gold bonus: All That We Touch goes to SXSW. This 2025 live recording at South by Southwest (SXSW) Sydney is a panel discussion among experts who dive deeper into food security, responsibility for pollution, and other topics crucial to conversations around the circular nutrient economy. Basically, a policymaker, water utilities manager, researcher and garlic farmer sit down for a chat about peecycling.
  - All That We Touch … at the pub. During this live recording from Gadigal land, Sydney, Jordan and Kerry share a drink with Professor Stuart White, Director of ISF, and discuss which is stranger: Recycling the nutrients from our pee or the fact that humans are the only species on earth that doesn’t recycle its nutrients.
- And finally, you can vote All That We Touch: Liquid Gold for the global Signal Listener’s Choice Awards (Voting closes Thursday, October 15).
October 7, 2026
Book Review: White Light casts a dark shadow

For his senior thesis work at Princeton, Jack Lohmann spent a month on Nauru, a Pacific island once rich in phosphate rock and now a decrepit relic. Nauru’s history of destructive mining is a cautionary tale to which Lohmann devotes an immense swath of his new book — White Light: The Elemental Role of Phosphorus in Our Cells, in Our Food, and in Our World (Pantheon Books, 2025).

The book unfolds the relationship between humanity and phosphorus rather than describing practical ways that societies can recycle human nutrients now. A few solutions are mentioned in passing, almost as a teaser (“In Japan, half of all human sewage is still made into fertilizer.”). Lohmann concludes: “Putting waste at the center of farming—where it always, until recently, had been—is a democratic action…. Waste is universally emitted and individually controlled.” You can’t argue with that. But how do we get out of the fix we’re in? White Light doesn’t answer this question, yet it’s still an important read for people who are seeking to understand the role of phosphorus in modern agricultural settings.

Partly lyrical and sometimes journalistic, White Light explores how phosphorus is central to life, growth, and rebirth. The black and white illustrations that begin each chapter, created by Alice Maiden, resemble block prints and gently remind us of nature’s cycles:

“In the moments that follow the death of a whale, when the light disappears and is swallowed by dark, the body’s weight draws to the base of the sea and compresses. It settles in mud. It forms an environment known as a whale fall, a world that will last for decades.”

Lohmann reminds us that rocks containing phosphorus — a rare element that’s critical for life —lend it to plants, which relinquish it to an herbivore’s bones, which ultimately find their way back to the sea. The author is critical of how industrial agriculture doesn’t foster soils containing organic matter, bacteria, and fungi. These are needed to make phosphorus-containing fertilizers fully available to crops. “On the whole,” he writes, “crops generally absorb one-fifth of the phosphate that is applied to the soil…. Around the world today, 70 percent of cropland contains more phosphate than it needs—although many of those soils, depleted of life, do not provide their phosphate to the crops that grow within them.”

In describing modern industrial agricultural practices, Lohmann pivots to those being studied since 1843 at England’s Rothamsted Research, the world’s oldest experimental station. “Each year,” he writes, “the amount of phosphorus that slips away through…wasted sewage, unused manure, food waste, and erosion—totals more than the amount that is mined. If phosphorus were reused as it once was—and as it still is in some communities around the world—mined sources would be all but unnecessary.” Rothamsted, so rooted in the past, is looking toward that future, and so must all of us.

April 21, 2026
Top 5 reasons why The Sewage Question still stands (A book review)

“It need hardly be stated that the removal of human excrements out of cities and towns has always been a question of the highest importance, both from considerations of public health and national economy.”

Nineteenth century engineer Frederick Krepp had a lot to say about sewage. In 1867, when he published The Sewage Question (Longmans, Green and Co press), cities around the world were desperate for a solution to their poopy problems. Krepp had a solution for them — the pneumatic air toilet. Though his preferred design didn’t replace the flush toilet, he left a fascinating book detailing the 19^th century’s wild explorations with sewage, with lessons ripe for our modern day problems.

The mid-1800s were the heyday of sewage solutions. At this time, flush toilets were newly popular, but there weren’t systems to manage the wastewater. So sewage overflowed in towns, poisoning the water, killing fish, spreading disease and causing smells so awful they shut down Parliament.

Illustration of the waterborne cause cholera from 18 Aug 1866 edition of the satirical magazine “Fun”

City government and private industry looked for solutions. They experimented, tinkered, invested huge amounts of money, and threw up their hands. Most of the book’s 200 pages seeks to answer the question at the front of everyone’s mind: “What is the cheapest and most efficient technical process for rendering human excreta useful instead of dangerous?”

Krepp discusses the social and economic impacts of poorly managed sewage and lessons from failed nations who neglected agriculture. To Krepp, sewage and agriculture were intrinsically linked: people ate food from the land and excreted nutrients, which should be returned to the land.

Reserves for a vacuum system in Amsterdam. PHOTO: City Archief Amsterdam

Next, he complains about water flush toilets and the high cost for town sewers. His critiques echo the same problems we face today in attempts to bring safe sanitation to the 40 percent of the world that lacks it.

The bulk of the book covers all the sewer schemes of the day — and there were many! Including air closets, earth closets, buckets and pneumatic carts.

Here are five take-away lessons from The Sewage Question:

1. Sewage has value. In the 1800s, the majority of people believed sewage had value; they understood nutrients had to be replaced from farmlands to have productive crops. The problem was how to get the nutrients back out once water was used to transport feces. Writes Krepp: “We have seen how bountiful the reward, if we obey the divine Laws of Nature, by applying to agriculture the most valuable mineral and organic substances daily ejected from our bodies and how severe the punishment if we neglect to do so..[and allow them to pollute]”

2. Proper treatment of feces is necessary for a healthy society. On page two, Krepp lays out his view of governments: they exist to secure life, liberty and happiness for people, which relies on public health. Healthy people, he points out, need abundant food, clean air and an unlimited supply of clean water. Feces must be properly managed to meet these needs. “All efforts at sound civil government must fail, unless they secure these primary conditions of human happiness,” he writes.

3. The economy is tied to nature’s laws. Krepp calls this the sublime laws of nature and cautions that neglect of these laws leads to national decay. He emphasizes nutrient cycling and the need to “return to the soil the minimal ingredients we take from it.”

4. It’s harder to remove nutrients from wastewater than to keep urine and feces separated from the start. Many of the schemes outlined in The Sewage Question attempt to turn wastewater into a dry fertilizer, with dismal results. They proved, in myriad ways, it’s harder to remove nutrients from liquid wastewater than it is to compost humanure manure from dry toilets.

One epic failure took place in Birmingham, a riverside town of 300,000 people. They created filter beds with gravel and sand, in attempts to remove poop from wastewater. But the filter beds became choked and useless and the sludge wouldn’t dry and so no one wanted it for their farms.

Tank at the sewage farm, near Barking, London. Published in The Illustrated London News, 26 September 1868.

5. Sanitation systems must manage excreta from the toilet all the way until it’s returned to the earth. Krepp’s preference was the pneumatic toilet invented by Charles Lierner, whom Krepp had a business relationship with. This system managed feces from the house, to tanks, to transport, to special farming tools that delivered it into the earth. He also spoke favorably about the dry toilet options, such as the earth closet system of Rev. Henry Moule.

You can read a free digital copy of The Sewage Question or purchase a reprint from Forgotten Books.

May our labour not prove in vain, but assist in opening and smoothing the road to new fields of honourable and useful enterprise!

-Frederick Krepp, May 22, 1877

This plough is designed to deliver humane manure into the soil from barrels. Credit: The Sewage Question pg. 128.

April 2, 2026
Book Review: The Devil’s Element

Stories propel the phosphorus dilemma to an unfinished climax

The Devil’s Element: Phosphorus and a World Out of Balance (2023, W. W. Norton & Co, 228 pp.), bursts with stories, some of which you may not want to hear. Exploitation. Greed. Pollution. But insight, bravery, ingenuity and persistence, too.

In the riveting style of a newspaper reporter, Dan Egan draws us into one of the biggest environmental dramas of our time: the discovery of phosphorus as a soil amendment, the worldwide quest for it, the profligate use of it in the US, and the ways phosphorus is poisoning our fresh water, from Lake Erie to Lake Okeechobee.

His clear, fast-moving prose can tempt the curious, whether that be teen or adult, scientist or nonscientist:

Simanski was alone on the shoreline that day as he ambled, eyes down, over the sweep of rocks squeezed between the tongues of the lazy, glassy Baltic waves and a thirty-foot-high bluff when he spotted what he thought was a piece of fossilized oyster shell about the size of a US quarter. He didn’t consider the orangish stone a prize find, but he thought it was worth bringing home to show his wife. So the sixty-eight-year-old stooped over, picked it up and dropped it in his pants pocket….

After about ten minutes, Simanski heard a pop and felt a sharp pain near his hip, and when he looked down he saw yellow flames flaring from his left leg. “It was like lightning coming out of my jeans. Like a flash,” said Simanski, who was initially more baffled than frightened….

Bewilderment turned to terror after Simanski shoved his hand into this pocket to snuff out whatever it was that caused the fire and he felt nothing but a viscous substance that had the consistency of melted chocolate. When he jerked his hand out of his pocket each fingertip was covered in the goo and ablaze like its own candle.

Egan explains that those orange nuggets in the Baltic region aren’t gemstones but fragments of “some of the most dangerous stuff you can find on the periodic table—elemental phosphorus.” When bonded with oxygen, phosphorus becomes the stable phosphate that is essential to life, the “P” in our fertilizers that, along with nitrogen and potassium, spurs plant growth.

With a degree in history and a graduate degree from the Columbia School of Journalism, Egan gravitates to the long view of how we ended up where we’re heading. And where we’re heading is dire. We’re raiding dwindling phosphorus reserves and pouring it on crops. As phosphate drains to lakes and oceans, it’s feeding algae that choke waterways, suck out the oxygen, and disrupt the balance of life itself.

The phosphorus boom bedevils us still

The Devil’s Element is divided into two main parts. In the first, The Race for Phosphorus, the author takes us back several centuries to a time when guano, crushed bones, and pulverized rocks were discovered to boost crop growth, and the intense competition over who could mine them.

If his wince-inducing details don’t lure you onward, the predictions from some of his sources will. In the “War of the Sands” chapter, Egan writes, “Unlike manure, which is manufactured daily…the phosphorus rock deposits that sustain the world’s modern agriculture system do not regenerate on a human time scale. This will, eventually, likely pose a problem for every person on the planet….” Then he describes billionaire Jeremy Grantham’s ability to predict bad times ahead, like the tech bubble in 2000 and the 2008 housing crash. Regarding phosphorus fertilizers, Grantham says, “’There seems to be only one conclusion: their use must be drastically reduced in the next 20-40 years or we will begin to starve.’” While scientists disagree about exactly how long our reserves will last, there’s consensus that Morocco and Western Sahara have about 70-80% of the planet’s phosphorus reserves—and those are destined to be more valuable than oil.

In the second section, The Cost of Phosphorus, Egan unfurls several environmental sagas. After goliathian Procter and Gamble hooks American households on phosphate detergents, one scientist living in the wilds of Canada gathers the data and a photograph that turns the Tide (so to speak). Due to state bans and voluntary reformulations by manufacturers, U.S. household laundry and dishwasher detergents are phosphate-free today, but agriculture is a different story. The phosphates in fertilizers not absorbed by crops, in combination with those in livestock manure, continue to pour into the Great Lakes and other U.S. waterways. “The number of animals in the…[Lake Erie] watershed more than doubled to twenty million between 2005 and 2018,” writes Egan, “while the amount of manure-based phosphorus added to the watershed grew by 67 percent, to 10,600 tons annually. Those farming operations collectively produce as much excreta as a city of at least several million people. And…it eventually winds up in Lake Erie.”

As a journalist in residence at the University of Wisconsin-Milwaukee’s School of Freshwater Sciences and the author of The Death and Life of the Great Lakes (2018), Egan knows this dilemma well. But he admits to not being prescriptive. He ends the book with only a few ways we might be able to get ourselves out of the harmful algal-blooming mess we’ve created. The brief chapter called “Waste Not”—in the equally short Future section—explains the need to better manage manure in agricultural settings and sewage in cities. He delivers a quick overview of the immense potential benefit of upscaling urine-recovery technology by describing the University of Michigan’s bathrooms, the Rich Earth Institute’s urine diversion projects, and the sewage treatment plant in Hamburg, Germany—powered by captured methane and deriving phosphorus atoms from its biosolids. The overarching message isn’t lost on the reader: people are trying, but there’s no easy fix.

March 19, 2026
A better way to go? Here’s 7 takeaways from a toilet museum
“Half the world needs a toilet while the other half needs a better one.”

That’s according to the Bill and Melinda Gate’s Foundation. It’s critical the 3.5 billion people who currently lack safe sanitation options get them. But what’s wrong with the rest of our toilets? A few things, it turns out:
- Flush toilets hog precious water and flush nutrients down the drain.
- They often pollute the environment and can spread disease.
- Wastewater treatment plants and the infrastructure needed to maintain them are expensive.
- And there are better options.
Last month, I visited the exhibit, “A Better Way to Go: Toilets and the Future of Sanitation.” It’s at the Discovery Center in Seattle, curated by the Bill and Melinda Gate’s Foundation. Here’s a peak at what’s inside.
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April 28, 2024