Brown gold, a manna thrown into the bowl

The world is turning its nose up at brown gold and throwing one of the main highly renewable natural resources on the planet down the drain. In his latest essay, journalist Bryn Nelson goes around the bush to explore the many facets of human poop, and the untold potential of these daily personal parcels.

Gold mine or odorous waste? The author of the most recent book The Flush: The Remarkable Science of an Unlikely Treasure, literally plunged into the heart of the subject to explore the sinuous and slippery road followed by human waste, from the colon to the purification plant. Because not only the fruits hated by our intestines have the potential to become carbs (poop power), says Nelson, they also contain a whole pharmacopoeia, a zoo of useful bacteria as well as the “footprints” of past and future generations.

Second producer of manure on Earth after livestock, the human species gratifies the planet, year after year, with approximately 800 million tons of stool. But like Homo sapiens measures its progress by the yardstick of its genius to make them disappear, kilometers of sewers and innumerable factories have been erected to zap these cursed faeces. Tons of chlorine are injected into it before spitting out solid sludge, which is then burned or transported by truck to be buried. As far as money and GHGs are concerned, we can do better with this infinite windfall which should become a “product” rather than waste, argues Bryn Nelson. In the United States, burying these foul materials generates 15% of the total GHG linked to methane, which is the equivalent of the emissions from 20 million cars.

« It’s the least useful way to get rid of it, » he says. They are transported elsewhere, harming the environment by polluting the air and water. »

On the scale of humanity, the by-product of our meals the day before would represent a gas energy potential worth 9.5 billion per year, estimates the United Nations. Going to the small corner could fuel powerful bioreactors. This is particularly the case in Oslo, where activating the toilet flush helps to supply biogas to a fleet of dumpsters and 15% of the city’s buses, explains the reporter. Even NASA is interested in the » astro poop — solid and liquid waste from astronauts — as a possible source of energy and drinking water for future missions to Mars.

Hot chestnuts

Once heated and purified, mountains of biosolids from sewage plants could serve as a very effective fertilizer, as the author found in Washington state, where a plant produces 4,000 truckloads of human fertilizer each year. “Loop”.

In order to put the hand in the dough, the author spread this brown mash in his new vegetable garden. “It doesn’t smell like animal manure. We have a psychological block; yet the process of pooping is the easiest way to recycle organic matter,” says Bryn Nelson, noting that dinosaurs and pachyderms enriched the soil with their dung for millions of years. “Dung is the beginning of life! he says.

This is after a report on the effect of fecal microbiota (FMT) transplantation in people severely infected with the bacteria It’s hard that the microbiologist has begun his exploration of the other side of the poop. Transferred by nasal catheter or by endoscopy, the fecal transplant from healthy individuals makes it possible to rebalance the intestinal flora of patients deprived of bacteria capable of fighting other, potentially fatal bacteria. But the use of this technique remains very limited for the moment.

“An unknown territory lies dormant within us. Sowing good bacteria can help fight resistant bacteria. The sadness is that loathing continues to kill people who might benefit from these treatments. »

Shit then

What is human faeces heated from? Bryn Nelson tracked his own transit through applications, measuring the effect of his daily inputs (food, medication, etc.) on his “outputs”. Composed of 50% bacteria, faeces – oblong, liquid or granulated – say a lot about the state of our colon, and their flotation is a guarantee of health, notes the journalist.

The many inhabitants of the microbiota make up our digestive system and compost, like an organ, everything we swallow. But, because of antibiotics and diets rich in “hamburger fries”, the Western microbiota is breaking down and its stools are twice as poor in fiber as those of African people. These also contain up to four times less bacteria. Researchers are also criss-crossing the planet to collect the faeces of isolated tribes, in the hope of finding bacteria that have disappeared from modern colons.

Certainly less cute than pandas, several tenants of our stomachs are threatened with extinction by antibacterial cocktails, explains the author. More than our faeces, the whole organism is affected. “Certain bacterial lines essential to our immune system, which may contain possible medical treatments, are threatened. If we lose them, it’s a pharmacopoeia that will disappear forever,” explains Bryn Nelson.

To save this fauna from the shadows, the Global Microbiome Conservancy—inspired by the World Seed Vault buried under the ice in Norway—has created a « poop bank » in the United States, a global refuge for microbes, housing 10,000 bacterial strains from manure collected around the world.

The pandemic has highlighted the usefulness of wastewater for measuring the progress of COVID-19 in several countries in real time, recalls the author of The Flush. Used as a barometer of addiction to opioids and other drugs, brown water testing has also recently detected the polio virus in New York. » Poop doesn’t lie “says the microbiologist.

Even coprolites — fossilized droppings — can tell a lot about the secrets of our ancestors. Bacterial DNA contained in a generous Viking-age specimen unearthed in London revealed that its author was infested with roundworms and shipworms, and that he ate meat and corn. The coprolites collected in the latrines of the Silk Road have also made it possible to shed light on the parasites contained in the stomachs of those who relieved themselves there over the centuries and on the food they consumed.

All about you

Faeces are such a precious imprint that stealing them is part of espionage techniques, the reporter recalls. In Russia, during Mao Zedong’s visits, KGB agents stole the contents of toilets to scrutinize the turds of the father of the Chinese Revolution. Fearing that the same could be done with his stool, North Korea’s Supreme Leader King Jong-un brought his own portable bowl on a visit to Singapore in 2018, so as not to leave any intimate secrets behind. him.

“This underestimated material holds a lot of scientific potential,” says Nelson. In Oregon, microbreweries even produce beer from wastewater, filtered and purified. With the challenges brought on by climate change, our future will depend in part on our ability to dispose of our own poop more responsibly. »

As the author concludes so well in his brick (of paper), the answers to the challenges of the next century could well arise from the most surprising packages!

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