Like the dream of ancient alchemists of turning base metals into precious ones, scientists today believe they can extract gold, silver and platinum from human shit.
I have been living in Mexico City for more than twenty-five years yet still when I eat out I quite often get a case of the bad shits. As I sit on the toilet, I can’t help but curse the city for the position I’m in.
The shit that I and millions of other bums dump each day into a toilet takes an amazing voyage beneath the city streets, through six thousand miles of pipes, 68 pump stations and across almost 100 miles of canals, tunnels, dikes and artificial lakes, yet still it has an uncanny knack of finding its way back to me.
Due to all the leaky or burst pipes, aguas negras (literally, black waters) constantly escape from the sewage system and leach down into the earth beneath Mexico City, seeping into the well water used to supply homes throughout the city.
This underground sea of excremental sludge has a way of surging up to the surface - especially during rainy season - flooding homes throughout the city and provoking health disasters: during the 2011 Great Black Flood, 60,000 inhabitants in Iztapalapa had their homes inundated by human turds.
And that’s only the shit from those who are fortunate enough to possess plumbing. Around half of all people in the city lack access to toilets and those who prefer not to take a dump on the street are forced to seek out public toilets.
To keep the plumbing from getting backed up, used toilet paper isn’t flushed down the drain in these public bathrooms but is instead tossed into baskets. This huge wad of brown paper eventually makes its way to the open-air garbage dumps where, along with millions of dirty diapers, it is left to rot under the sun. These tons of fecal matter eventually dry up and go airborne, eventually descending as “brown snow.”
Given that the average human being produces around a pound of crap a day, which multiplied by the number of people living in this city adds up to more than 20 million pounds of shit, not to mention the tons of dog, cat, rat and squirrel shit that accumulates on the street and in parks, you get a good idea of what I and everyone else living here in Mexico City must wade through each day.
The disposal of human shit has always been a major problem in Mexico City. Since the Spanish colony was first established here, canals and rivers have been used as dumping grounds for human feces, with thousands of prisoners and indigenous workers forced to dredge the constantly clogged waterways.
The fresh water lakes that irrigated the city’s crops and provided drinking water also served as dumping grounds, and this contaminated water (so toxic it was said to burn the tail feathers off of ducks) spread its stench and disease throughout the city. To deal with this situation, three huge, costly sewage works were built to funnel the aguas negras out of the city: the Western Interceptor in 1789, the Great Canal in 1900 and the Central Source in 1975.
In 1971, the federal government selected the Mezquital Valley in the state of Hidalgo, about 50 miles north of Mexico City, as the ideal destination for the majority of the capital’s tons of human waste. In fact, though, towns in the region had already been receiving fecal matter from the capital ever since the first sewage pipe funnelled shit outside of Mexico City in 1608.
As the land in the Mezquital Valley is arid and lacks its own water supply, raw sewage from Mexico City serves to irrigate almost 40,000 acres of cropland. The sewage pumped into the area receives absolutely no treatment, even the most basic one of separating solids from liquids, and thus the Mezquital Valley, watered by the greatest concentration of human shit in all of Latin America, is commonly referred to as the world’s largest outhouse.
Human sewage might help float the local economy but it does so at a price. Local farmers are prone to several acute and chronic health problems, especially skin and intestinal diseases caused by all sorts of especially nasty parasites. But they are not the only people infected. The vegetables grown in the Mezquital Valley - along with all the microorganisms residing upon them - are transported daily to Mexico City’s markets and supermarkets and can wind up in my salad.
Back in the 1990s, my adopted city was the most populated and most polluted on earth. Today, however, it doesn’t even rank in the top 10, not so much because it’s cleaned up its act but because many more megacities have surpassed it in terms of population and in damage inflicted onto their environment: more large intestines, more pollution.
Two billion people on this planet live without sanitation facilities and around one billion people, representing 15 percent of the world’s population, relieve their bowels outdoors in what experts in the field call “open defecation.” India ranks number one, with about 600 million, almost half the country’s population, adding their share, followed by Indonesia (54 million), Pakistan (41 million), Nigeria, (39 million) and Ethiopia (34 million).
The level of development of a city can be measured as the distance between its inhabitants and human excrement. More than one-third of the world’s population takes a dump in places where their shit will come into contact with other human beings in one way or another, thus affecting their health and contaminating drinking water. Greater levels of open defecation are associated with higher levels of infant mortality, undernutrition, poverty and unequal distribution of wealth.
If you live in a developed country, you can probably just flush your problems away. In underdeveloped countries, especially in the megacities, keeping your own shit and that of others away from you and your family is a lot more difficult. In the countryside, there is enough land to absorb such organic material, but within cities, human shit tends to just sit there and rot, eventually entering the city’s air and water supply.
Many major cities were settled by rivers, which not only supplied them with an unending supply of drinking water but also served to transport their excrement away to faraway lands or oceans. Few megacities, however, are located around rivers, and even when there is a river or an ocean nearby, megacities tend to transform them into giant toilets.
In Karachi, Pakistan, a megacity with an even greater population than Mexico City, 80 percent of untreated wastewater is discharged directly into the Arabian Sea. Dhaka, Bangladesh, with a population of 15 million and growing, dumps two-thirds of its waste directly into local waterways, leading to widespread, fatal diseases such as cholera and typhoid.
Getting human shit out of a land-locked city has always been difficult work, and in both developed and underdeveloped countries the poorest and most marginal are the ones who have always borne the burden. Since India gained independence, hauling crap out of the cities is illegal, yet it is estimated that over one million people there are still paid to collect human shit.
In the Hindu caste system, human shit is believed to pollute the workers who come into contact with it, and this pollution is considered contagious, thus those whose job is to dispose of human waste are considered “untouchables”. Untouchables are socially and physically marginalized, unable to enter temples or schools. Their trade is passed down from generation to generation and they are only allowed to marry amongst themselves, thus perpetuating their social marginalization.
Although untouchables are well known, almost every major city has employed workers to shovel shit out of their cities. In Tudor England, those employed to clean out public toilets and cesspits were called “gong farmers” or “midnight mechanics”, filling up “honey buckets” with shit and driving them out of the city on “honey wagons.”
The content of the “honey buckets” was called “night soil” and was sold to farmers as fertilizer. The use of humanure (human feces used as manure) in Japan was also common up until WWII, with the shit of wealthy people fetching a higher price as it contained more nutrients.
Human shit gives rise to many economies. Carlos Slim, a Mexican who is one of the wealthiest men in the world, along with several of the biggest entrepreneurs and corporations around the world, have moved into the lucrative business of water treatment, purifying toilet water and reselling it back to the very people who flushed it away, thus privatizing a basic natural element.
On a more local level, the lack of plumbing in so many houses in Mexico City has led to the recent creation of hundreds of informal “public” bathrooms that charge a fee to take a dump anywhere around the city. In cities in western India, realizing the damage that open defecation can wreak about the local population, one state now actually pays residents to use one of its 300 public toilets.
In Accra, Ghana, as in other cities around the world, human shit is now being converted into biodiesel. Biodiesel is the product of anaerobic bacteria that consume human excrement (one species’ waste is another’s profit). In England, a Bio Bus that shuttles people between Bath and Bristol converts “brown” waste into biomethane gas, a “green” source of energy that actually smells much less than regular gasoline when expelled by a combustion engine.
With the help of microbes, human excrement is also being brewed into plastic. Being that five percent of the crude oil consumed in the USA goes into producing plastic products, such as shopping bags and water bottles, this brown material has now become a very green source for plastic.
One promising future industry is recycling and extracting valuable elements from human excrement. Like the dream of ancient alchemists of turning base metals into precious ones, scientists today believe they can extract gold, silver and platinum from human shit. The US Geological Survey has obtained gold at the level of a “minimal mineral deposit” from human waste, while a sewage treatment plant in Tokyo claims it is extracting as much gold per pound as any of the country’s leading gold mines.
Other rare elements, such as palladium and vanadium, commonly used in electronic appliances and in the production of alloys, are also present in human shit in significant quantities. According to some geological estimations, the shit each person produces each year is worth around $13, which when multiplied by the millions and millions of people in a megacity represents no small fortune.
The more chemically polluted and oversaturated an urban environment, the more metals and other elements can be culled from its caca. Collecting lead from feces could one day not only give rise to a moneymaking recycling industry, but it could also become a way to help decontaminate the environment.
Due to recent medical research, it is believed that by introducing other people’s shit into your own body, through enemas, colonoscopies, tubes or in gelatin capsules, certain chronic illnesses of the large intestine that are resistant to conventional medicine, such as Crohn’s disease, can be successfully treated.
Fecal transplants - or the more technical term, fecal microbiota transplantation - when fully accepted by medical institutions, could also become the best, cheapest, simplest, healthiest way of getting humans to dispose of other people’s shit.
Kurt Hollander is originally from New York City, lived in Mexico City for over 25 years, and is currently living in Cali, Colombia. He is a writer and a fine art/documentary photographer.