When he was a teenager, David Sedlak was mesmerized by a novel. “It happened while I was in high school, a time when many young people are ‘abducted’ by science fiction,” this US civil and environmental engineer tells SINC. University of California at Berkeley.
This book, however, was different, ambitious, like nothing he had read before. On Dune (1965), the writer Frank Herbert built an entire universe from the combination of elements of medieval culture – an empire in ruins mediated by feudal relations, monastic orders and legends of the advent of a messiah – with high-tech touches such as ships space, genetic manipulation and eugenics.
Beyond the galactic adventures and the eternal struggle between good and evil in this saga, which has just been adapted to the cinema again in a movie by Denis Villeneuve, it was a long meditation on deeper issues, a commentary on the rise of religious fundamentalism and the madness of clinging to power, as well as an allegory on colonialism and the destruction of important ecosystems for the acquisition of fuels ( the sought-after ‘spice’ in history refers directly to oil).
At the same time as the biologist Rachel carson denounced the excessive use of pesticides in his book Silent spring (1962) and inaugurated contemporary environmentalism, Herbert delved from fiction into global awareness of environmental concerns.
In addition to the environmental message that would make it one of the first works of the now popular subgenre cli-f (or weather fiction), Sedlak was fascinated by a costume piece in this story set in the distant future on a desert planet called Arrakis.
As Sedlak recalls, one of the aspects that most caught his attention in the novel “was that the protagonists wore special suits that captured the moisture and waste produced by the body, such as urine and feces, and recycled them so that their user could hydrate through a tube connected to his mouth “.
Herbert called them stillsuits (or distillation suits) and, although he did not elaborate on its technical details, it was about the evolution of the gigantic and clumsy suits of the astronauts of his time that allowed them to survive in uninhabitable environments such as outer space.
“That image stuck with me forever, even though I didn’t live in a desert area,” says Sedlak. “I grew up near water in Oyster Bay, New York. I spent a lot of time outdoors around the bay. Back then it was being announced that water could one day become as valuable as gold. Dune he planted a seed in me that, without knowing it, grew over time. ”
The city as a living organism
Sedlak forgot Dune and the stillsuits during years. Over time, he dedicated himself to studying and developing new technologies to provide an abundant and safe water supply for future generations, especially as droughts become more frequent in certain regions of the world.
To do this, this researcher directs a team in which he studies from the mechanisms through which chemical products are degraded in advanced water treatment plants to how to improve the desalination processes of seawater for consumption.
Until a few years ago, he reread the novels that make up Herbert’s space epic with his daughter. “The rediscovery of this treasure of my youth made me think: could I build a distillation suit for an entire city?”
The idea of considering the city as a body, in fact, was not entirely new. It was born in the nineteenth century but was installed in the sixties of the last century. It became known as’urban metabolism‘: conceiving a city as a living organism that feeds on food, generates waste, needs energy or becomes ill if it is not taken care of. And dies.
Sedlak believes that in cities, like the suits in Herbert’s novel, a closed system could be created without the need to go out and fetch more water. It would only be enough to recycle it.
Stories about water scarcity are very powerful in fiction. Over and over post-apocalyptic movies, like Mad max (1985) and Tank girl (1995) or Quantum of Solace (2008), and novels, such as The parable of the sower by Octavia E. Butler, Water knife by Paolo Bacigalupi or The memory of water by Emmi Itäranta, recall how the climate crisis has exacerbated droughts and anticipate the emergence of conflicts around our most valuable resource.
“In many countries, unless you are very poor, you have enough water to drink, cook, take a shower, wash your car, so it does not seem that we live in one of these dystopias,” says Sedlak, who is also the author of the book Water 4.0: The Past, Present, and Future of the World’s Most Vital Resource.
However, “water shortages or droughts have a great impact on everyone’s lives because they can affect the food supply or alter the landscape. In California, we are experiencing terrible fires and smoke reaches us every day. water is making it difficult to extinguish them. Those dystopian nightmares of a future without water or of fights over the last drop are becoming an increasingly tangible reality for millions of people around the world “, comments this engineer.
The water crisis is not a threat. In many parts of the planet it is a reality. The UN estimates that by 2025 some 1.8 billion people will live in areas with ‘water stress’. The extreme drought on the Colorado River It has led the US government, in recent weeks, to push for mandatory water cuts in Arizona and Nevada.
Argentina’s Paraná River – the second longest in South America after the Amazon – is suffering the worst drought in 77 years. Brazil, for its part, declared a water emergency in May.
With his team, Sedlak explores how cities will have to adapt to face the effects of climate change, population growth and the fight for water resources.
The researcher indicates that this can be achieved at different levels. Just as many people have solar panels on the roofs of their houses and do not need to connect to the electricity grid, a building or a home can capture rainwater and recycle it. “The systems that allow this are improving,” he says. “Reverse osmosis technology used to remove salinity from seawater is increasingly accessible.”
But it’s not enough. Sedlak believes it is necessary to completely abandon centralized wastewater treatment plant schemes and build distributive recycling plants throughout the city.
It indicates that “the systems we use to move water around cities can be very inefficient. In some countries, between 20% to 40% of water is lost before reaching homes.”
Furthermore, “a lot of energy is required to move the water several kilometers from the central to the user. Instead of having one or two plants in a city of one million or ten million inhabitants, one could have 20, 30, 50 treatment plants. smaller ones with greater autonomy and that can operate independently. And instead of having a staff of full-time operators, they could be executed remotely with sensors and actuators, “he emphasizes.
Innovations with resistors
This proposed new planning consists of a transition to next-generation water systems and at the same time a continuation of a repeated cycle of growth, failure, and reinvention of urban water systems that has occurred over the last 2,500 years: piped water systems. and the sewers built by the ancient Romans were replicated in European cities that were growing very rapidly during the first wave of global industrialization in the 19th century.
Drinking water treatment was the next revolution: it stopped the spread of water-borne diseases – such as cholera and typhoid fever – and generated unimaginable health benefits.
This was followed by the standardization of wastewater treatment plants after decades of decline in the rivers, lakes and estuaries that surround cities. In Windhoek, the capital of Namibia – one of the driest countries in Africa – they produce drinking water from treatment of your wastewater since 1968.
In Singapore, where drinking water is a national security issue and half of its current water supplies are imported from neighboring Malaysia, they combine desalination plants, wastewater recycling and efficient rainwater harvesting through a network of drains, canals, rivers, stormwater, collection ponds and reservoirs.
However promising they may seem, these strategies may run into resistance. “Drinking water that falls on the roof and using it is something that many people accept,” says Sedlak.
“But when it comes to recycling wastewater, people get nervous. What we have seen in California, Australia and Singapore, places that have pioneered these systems. Therefore, it is necessary for people to become familiar with these technologies. There must be transparency and also trust in those who provide the water. Some communities have succeeded in creating these recycling systems. In others, where governments are not trusted, they failed “, says the engineer.
There are cultural reasons for these rejections. In religions such as Judeo-Christian or Islam, certain taboos regarding interacting with waste.
The example of the International Space Station
Changing these old conceptions will take time, but communities and governments can learn from successful examples, such as the International Space Station (ISS). 400 km from the earth’s surface, a closed loop system captures astronauts’ wastewater, such as urine, sweat, or even moisture from their breath. Then impurities and contaminants are filtered out of the water. The end product is drinking water that can be used to rehydrate food, wash or drink.
“The system may sound disgusting,” says chemist Enid J. Contes of the Ames Research Center from NASA – but the recycled water on the ISS is cleaner than most people on Earth drink. ”
The treated wastewater can also be used for growing food. “That has been more accepted around the world,” recalls Sedlak. “It’s been done for hundreds of years. In Israel, all wastewater is derived for crop irrigation. Also in China and parts of the United States. And it’s not just to grow grasslands for cattle. In California, we have a water recycling project in Monterrey where treated wastewater is used to grow strawberries and lettuce. ”
Like Sedlak and his team, all kinds of scientists, engineers and innovators around the world are working to develop new technologies and strategies that generate, supply and provide drinking water on which we humans depend so much.
In his documentary Brave blue world, Irish biochemist and producer Paul O’Callaghan says that in certain regions of Africa there are ‘harvest‘water from the atmosphere. In Northern California, they experiment with systems capable of ‘hunt‘the mist to capture up to 30 liters of drinking water in 24 hours, while a Danish company seeks to apply ISS recycling technology on Earth.
As Sedlak points out: “This wide range of innovations that allow us to safely collect, recycle and purify water is no longer a matter of science fiction.”