Time to clean up

Date 07.10.2021
Text T.Petersen, N. Papageorgiou, S. Kennedy, S. Parker & E. Barraud
Source EPFL
Photo Patric Sandri
Dimensions - EPFL Magazine
Humanity has made planet Earth a landfill. Scientists are now rushing for solutions. Our planet is in trouble and so are we. At the beginning of the 21st century, as we navigate the Anthropocene, a proposed geological epoch signifying the impact we are having on the Earth’s geology and ecosystems, exploding human consumption is driving unprecedented planetary change – we have literally trashed the planet. From the Mariana Trench to the edge of space, we live in a ticking time bomb of rubbish.

Scientists are deeply and tremendously aware of the enormous size of the problem we face and it’s evident that we live in a world where sustainability and our economic model – which means our way of life – are just not compatible. I think people should just say it,” says EPFL Professor Francesco Stellacci.  

Driven by runaway human consumption, plastic and other pollutants blight our landscapes and choke our rivers and oceans. The world generates more than 2-billion tonnes of solid waste annually, a figure expected to grow to 3.4-billion tonnes by 2050. At least a third is not managed in an environmentally safe manner. This garbage poisons our soils, runs into rivers and seeps into groundwater. It finds its way into our oceans, posing a threat to a wide variety of marine mammals and ecosystems. 

This trash also contributes to climate change. Rotting rubbish in landfills generates methane, estimated at more than 5% of global greenhouse gas emissions annually and anticipated to increase by a billion tonnes of CO2 equivalent within decades. 

As a result of our modern human lifestyles that generate all this waste, nature is crashing around us. Between 1970 and 2016, population sizes of mammals, birds, amphibians, reptiles and fish fell by 68%. Last month’s latest report from the Intergovernmental Panel on Climate Change has been described as a Code Red for humanity, with the impacts of the climate crisis occurring more and more frequently in every region on Earth. 

Why does this all matter? Because for our health, wealth and security, the human enterprise relies fundamentally on goods and services provided by nature, including food, clean water and medicine. To sustain modern human society, we will continue to need the resources of nature and a stable planetary system that, throughout history, has allowed us to thrive. Yet, the rapid change that we are causing through the rubbish that spews into our world is breaking down these planetary life support systems. 

Known as the Great Acceleration, it needs nothing short of a Great Cleanup. Can we do it, and if so, how? 

In this longread
  • Synthetic biology could prevent a hidden underground pollution
  • Water, water, everywhere. (But what’s in it?)
  • Reducing waste from farm to fork
  • All that glitters
  • A climate code red for humanity
  • Making space a safer place
  • Online cleanup: Getting rid of virtual rubbish
  • Can proteins help us clean the world?
Mountains of rubbish.
Infography © Emphase Sàrl


EPFL Assistant Professor Julia Schmale is an optimist but says it’s going to take every tool we have in the box. “When we start cleaning our atmosphere we can’t think in compartments, meaning technology versus behavior or atmosphere versus land. They go together. We need technical solutions, but these will only help in the long run if there is also behavior change. We need to replace fossil fuels with biofuels or other renewables, but we can’t consume forests for energy. To put it positively, reducing consumption means, for example, less transport of goods around the globe, resulting in less greenhouse emissions and fewer oil spills, helping to prevent contaminated soils, oceans and waterways, and mitigating climate change. Everything is connected”. “We can create technologies, but that doesn’t change behavior and it doesn’t change the long-term vision, unfortunately,” says EPFL’s Florian Breider. He believes that Western societies need to curb consumption and find new definitions of what constitutes well-being. “We have, as a society, a certain sense of what creates well-being, that is to own material things, for instance. But what if we return more to a society of functionality, where we use things for their function, not for the pleasure of owning a particular object?” 

From research into new plastics for a circular economy and carbon capture and storage, to nanobiotechnologies to reduce food waste and the removal of pollutants from water, EPFL is at the forefront of research to help clean our world. 

Whatever the balance between technology and behavior change, Francesco Stellacci expresses the urgency and determination of scientists who work on research that may determine the future of human society: “There’s no magic wand here, we can’t hide and forget the problems exist. We are a resilient species, but we need to get hit before we react. Once we get it we do act. In science, we get it and we are acting, as fast and as strongly as we can.”  ■

Mountains of rubbish.
Infography © Emphase Sàrl

We can create technologies, but that doesn’t change behavior and it doesn’t change the long-term vision, unfortunately

The soils

Synthetic biology could prevent a hidden underground pollution

Photo iStock
Dimensions - EPFL Magazine
Texts | Nik Papageorgiou
Even in organically cultivated fields, the soil can be polluted by an excess of copper from the treatments. EPFL’s team in the 2021 International Genetically Engineered Machine (iGEM) competition is designing a yeast-based system to keep that copper from damaging the vineyards.

For over a decade, EPFL students have taken part in iGEM, a synthetic biology competition that began as an MIT course in 2003 and has since evolved into a global contest. Each year, teams of university students spend their summer brainstorming, building, testing and implementing synthetic biology systems for a wide array of applications.  

The purpose of iGEM is to cultivate interdisciplinary collaboration and teamwork and showcase the potential of synthetic biology to address some of the world’s most complex problems. By bringing together ideas from different fields, iGEM encapsulates the broad trajectory of modern science and exemplifies much needed innovation and creativity.

This year, EPFL’s iGEM team consists of ten students from the Schools of Life Sciences, Basic Sciences, Engineering and Computer Sciences. Led by Professor Brian McCabe, a neuroscientist at EPFL’s Brain Mind Institute, the team is developing a solution to remove toxic copper from vineyard soils.

“In order to prevent fungal infections on their vines, vintners spray them with ‘bio-’ fungicides that contain copper,” explains McCabe. “But copper can be toxic; when it rains, it seeps into the soil and prevents new vines from growing.” Copper toxicity is also a problem for tea horticulture in developing countries. The conventional solution is to either move to new land or replace the soil – both costly and environmentally harmful endeavors.

This is where the creative innovation of EPFL’s 2021 iGEM team comes into play. To prevent copper from entering soil, the students developed a genetically engineered yeast or, more specifically, a copper-binding protein normally found inside yeast. 

The protein is called CUP1 and the team engineered it to also be produced on the yeast’s surface. “Yeast use copper in their metabolism,” says McCabe. “We developed yeast strains where CUP1 coats the exterior of the microorganism, enabling them to bind copper from the environment.”

In order to prevent fungal infections on their vines, vintners spray them with ‘bio-’ fungicides that contain copper”

Prof. Brian McCabe, a neuroscientist at EPFL’s Brain Mind Institute © Alain Herzog
Prof. Brian McCabe, a neuroscientist at EPFL’s Brain Mind Institute © Alain Herzog

The system of the iGEM team, named CuRe for “Copper (chemical element Cu) Removal”, takes advantage of synthetic biology to genetically modify yeast. The team can express multiple copies of CUP1 on the surface, each of which can bind eight atoms of copper.

Going back to vineyards, runoff water could be introduced into a bioreactor with the modified yeast where it would “mop up” the copper from fungicides. This purified water could then be reintroduced into the vineyard, keeping the soil copper-free and safe for replanting.

“CuRe is the result of a lot of enthusiasm, brainstorming, collaboration and hard work,” says McCabe. “The team is fine-tuning it, and thinking about the potential for commercialization in the future.”

The 2021 iGEM competition will take place online from 4–14 November, and already counts over 350 teams from across the world.

Prof. Brian McCabe, a neuroscientist at EPFL’s Brain Mind Institute © Alain Herzog

The team is fine-tuning it, and thinking about the potential for commercialization in the future. ”


Water, water, everywhere. (But what’s in it?)

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Sheena Kennedy
How often do you flush a toilet? Run your washing machine? Turn a tap and see clear, fresh water pour into your glass? We are privileged to have advanced systems of water purification that make what comes out of the tap typically safe for human consumption. But while the purified water we drink isn’t likely to make us sick, we are making the water “sick”— and this is upsetting our ecosystems.

Clear water? Not exactly. No matter how clear it looks, there is plenty going on at the micro scale in a sample of untreated surface water, whether from wetlands, streams, rivers, lakes, oceans or even snowcapped mountains. There are minerals such as salt and calcium, as well as small organisms like bacteria or plankton that play a role in the natural ecosystem. 

There are also many things in surface water that are direct by-products of the way we – humans – live. These include micropollutants that get into the water through wastewater and as runoff. Micropollutants can be heavy metals or organic chemicals, such as pharmaceuticals, industrial or household chemicals, and pesticides. Pathogenic bacteria, viruses, fungi and parasites introduced through wastewater can also cause illness. Finally, a high amount of microplastics and nanoplastics are of grave concern.

Illustration © Patric Sandri

Small pollutants, big impact

“Micropollutants are generally substances dissolved in the water or attached to the surface of sediment,” says Florian Breider, Head of EPFL’s Central Environmental Laboratory. “I won’t say that all the micropollutants in the water originate with humans. But let’s say 99.99% are there because of human activity.”

There are diverse ways that micropollutants harm aquatic life and the broader ecosystem. A chemical pollutant can directly poison species, or a virus may cause illness. Then there are less direct paths to harm. As an example, Christof Holliger, Head of the Laboratory for Environmental Biotechnology at EPFL, describes the trajectory of medication excreted through urine: “It’s shown to not degrade well in normal wastewater treatment plants. We’ve found that these can interrupt the endocrine system determining whether an organism is male or female. So, for some species, one could then find only males or only females downstream from the wastewater treatment plant, while upstream it was not like that. While they don’t directly kill the organisms, there’s an obvious link to the species survival.” 

It’s shown to not degrade well in normal wastewater treatment plants

Microorganisms that shouldn’t be there

In EPFL’s Environmental Chemistry Lab, a lot of the research these days is focused on human pathogens found in the water. “We deal mostly with human viruses,” say the lab’s head, Tamar Kohn. “They’re there by mistake, contrary to other microorganisms that are part of the natural ecosystem. They infect us, then we shed them into the wastewater system, then they get in the lake.” 

Bacteria and viruses can develop resistance to drugs or disinfectants meant to control them, which is an important threat to human health. The lab has shown that natural stressors, such as heat or UV rays, encountered in the environment can “kill off the weakest links” and select for viruses with enhanced resistance.

“There also seem to be correlations between different kinds of resistance, although we are still researching exactly why,” explains Kohn’s colleague, scientist Anna Carratalà Ripollès. “We’ve seen in different studies, for example, when viruses resist high temperatures, they resist chlorine; when they resist UV exposure, they resist the antiviral drug ribavirin.”

Kohn and Carratalà explain that their research can shed light on implications of climate change as well as the changes that can occur when these pathogens move from one environmental region to another due to factors such as human migration.

“Why are human bacterial and viral pathogens in water a problem? Well, because we swim in the water, we irrigate our food with it and essentially, it becomes our drinking water, we’re continuously exposed to it,” says Kohn. “It’s not so obvious to us in Switzerland because while waterborne infections happen here, they’re often not severe and/or not recognized as originating from the water. In other parts of the world, they contribute to major problems such as outbreaks, chronic disease and child mortality.”

Kohn says that many pathogens found in water are the same the world over. “The difference is in concentration,” she says, “and how well they are removed or inactivated before people drink it. In addition to vaccination, this water treatment and sanitation protects us in the West from getting very sick from waterborne illnesses that may chronically infect people in developing countries – even though we have some of the same pathogens in the water.”

In low- and middle-income countries, access to clean water is a fundamental issue that is only compounded by increased global water pollution. And it’s not just about drinking water. “Close to two billion people worldwide depend on healthcare facilities without basic water service,” says Cara Tobin, who is the Program Manager for Water, Sanitation and Hygiene at EPFL’s EssentialTech Centre, citing a 2020 report by the WHO.

Prof. Tamar Kohn, Environmental Chemistry Laboratory at EPFL @ Alain Herzog


Why are human bacterial and viral pathogens in water a problem? Well, because we swim in the water, we irrigate our food with it and essentially, it becomes our drinking water, we’re continuously exposed to it”

Great Pacific Garbage Patch @ Wikipedia
Great Pacific Garbage Patch @ Wikipedia

Grasping at paper straws

A knotted floating mass of plastics known as the “Great Pacific Garbage Patch”, blocking sunlight. A corpse of an albatross chick, its stomach clearly filled with plastic chunks. Images of both can be found in a National Geographic Encyclopedia entry, reference material for school-age children. Shocking as these photos are, the bigger problem is in the plastics you can’t see. While as much as 80% of marine debris is plastic in origin, most is not intact and identifiable by the naked eye. Rather, it is in the form of microplastics, less than a few millimeters in size, down to nanoplastics – a million times smaller than a millimeter.

“Our research has found that there is about the same proportion of microplastics in Lake Geneva as in the ocean,” says Breider. “For those particles at the nanoplastic level, we don’t yet actually know how much there is anywhere because we don’t have the technology to measure them in the environment. We do know from lab experiments that nanoplastic particles can be formed during the breakdown of bigger plastic particles and that they are potentially more toxic. That’s why it is important to develop technologies to quantify these particles in environmental samples and evaluate the effects on aquatic life, the ecosystem and human health.”

Plastics are made of various polymers that can contain numerous additives. One way aquatic life is impacted is very direct, by ingesting plastics. The albatross chick mentioned above was most likely killed directly by the physical load of plastic items in its belly, fed by its parent. But in many other cases, living beings are harmed by the unseen additives in the plastic as well as pollutants that have been carried by microplastics acting as vectors.

Of the multifaceted problem of plastics, Breider says: “Plastics are everywhere, far beyond grocery bags or plastic straws. One major issue my lab is working a lot on right now are particles from tires, which contain hundreds of polymers and other substances, some of which have been clearly shown to be very problematic for fish. In the US, a direct link has been shown between road traffic that generates these particles and a sharp decline in the salmon population on the American West Coast. This work is quite recent – for the moment we can assume, though, that there are similar effects elsewhere in the industrialized world. That’s what we’re studying.”

Furthermore, Breider posits that there are other dimensions to this issue, notably in developing regions. “In Switzerland and much of Europe, we export our used car tires to Africa. In discussion with a colleague in Senegal, we wondered if the issue of microplastics due to tires is compounded by the fact that they are using worn tires that are more likely to shed plastics, that are more toxic. This is speculation but worth investigating. And I think there is a responsibility for Western countries.”

Should we be switching out our plastic straws for paper or reusable? Sure, says Breider, but we need to understand that this move is mostly symbolic.

Great Pacific Garbage Patch @ Wikipedia

Our research has found that there is about the same proportion of microplastics in Lake Geneva as in the ocean,”

So what do we do?

“For those of us looking at the issue from the perspective of low- and middle-income countries, we need to tailor developed-world business models and technologies,” says Tobin. “We adapt to specific conditions, case by case. One example that we are involved in is called H2Ospital. To provide health facilities with a sustainable supply of clean water – without resorting to plastic bottles – we’ve explored the development and implementation of private water kiosks. It’s a solution that is self-sustaining and scalable.”

Looking at usage behaviors in industrialized countries, Breider sees a positive trend towards people being more aware of their choices as consumers. “At the industrial level,” he says, “there’s work to be done restricting use of chemicals in products. In a lot of products, there are chemical substances that are not needed, that are just there for esthetics or simply because it has always been done that way.”

Kohn adds that there are regulatory decisions to be made based on an acceptable level of risk: “The technology exists to reduce water contamination through treatment, for example, or we can improve monitoring and warning systems.” To take it one step further, Holliger proposes the possibility of extracting resources, to actually reap benefits from wastewater, not just make it less toxic. “For example, there’s a startup with technology to produce a fertilizer out of undiluted urine that is separated from the normal wastewater going to the sewer, a fertilizer which is safe for humans and the environment. Or, another example is bioplastic produced by bacteria that could be derived from organic pollution present in wastewater.”

Carratalà notes that it all begins with knowledge. “From the ecological side, there is still a lot we don’t know about the biological consequences of climate change,” she says. “Unlike pathogens, most microorganisms play such an important role in the functioning of the ecosystems – how they respond to climate change will determine the resilience of the aquatic ecosystems to global warming, for instance. Everything is interconnected.”

“Water, water, everywhere, nor any drop to drink,” bemoans the Mariner in part II of Samuel Coleridge’s 1798 poem The Rime of the Ancient Mariner. He and his crew are hopelessly stuck in dangerous, uncharted waters after having upset the balance of nature by killing their albatross guide. Are we in a similar situation? While we do not know to what extent we have upset the ecological balance, we know that resetting it will require further research, collaboration among numerous stakeholders and multiple strategies. 

The technology exists to reduce water contamination through treatment, for example, or we can improve monitoring and warning systems.”

Closing the loop on PET production

Current PET recycling technologies often face the challenge of mixed plastic types in the waste. Founded in February 2020, the EPFL spin-off DePoly is changing all this with a recycling process that can selectively treat PET plastic in the presence of other plastics. “Our innovative low-cost, low-energy process produces terephthalic acid (TPA) and monoethylene glycol (MEG) from post-consumer PET plastic waste. We depolymerize all PET plastics including mixed color, multi-layer and polyester fibers at room temperature, without any additional heat or pressure, and with sustainable and environmentally friendly chemicals only,” explains Dr Samantha Anderson, CEO and founder of DePoly. The resulting chemical products might then directly be used to make 100% recycled PET resins. According to the startup, every ton of plastic being recycled not only means less plastic pollution in landfill and our oceans but saves an amount of energy equivalent to 4 European households’ annual electricity consumption, 18 barrels of burnt oil or 10 passengers flying from London to New York.


Reducing waste from farm to fork

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Tanya Petersen et Sheena Kennedy
Food loss and waste is a major contributor to increasing food insecurity as well as climate change, biodiversity destruction and pollution, and biomass waste is a missed opportunity towards renewable energy. Addressing both could have huge social, economic and environmental benefits.

A year ago, in September 2020, the United Nations marked the first International Day of Awareness of Food Loss and Waste, urging the world to urgently tackle the problem or risk an even greater drop in food security and natural resources. Just six months later, the UN Environment Program’s Food Waste Index Report 2021 found that almost 20%, or more than 900-million tonnes, of global food production goes to waste each year. Almost two-thirds of this waste comes from households. 

At the same time, globally, 140-billion metric tonnes of biomass are generated every year from agriculture. Biomass is plant or animal material such as wood, residual stalks, leaves, roots or husks from fields, or animal husbandry waste. It is widely available, renewable and virtually free, making waste biomass an important resource. Using thermal, chemical or biochemical conversion methods, various value-added products can be produced from both kitchen waste and agricultural biomass, depending on the waste type. These range from, for instance, antioxidants to pigments to biopolymers. It is also an important source for energy in the form of, for example, bioethanol, biodiesel and biogas.  

Illustration © Patric Sandri

On the farm – a look at energy from biomass 

“A lot of people don’t realize it, but biomass is considered the most-used renewable energy source,” says Professor Edgard Gnansounou, Director of EPFL’s Bioenergy and Energy Planning Research Group. “Some are reluctant to call it renewable because first-generation conversion methods derived biofuels from raw material, resulting in issues like deforestation or competition between food and fuel. But in the right locale, with appropriate sourcing and modern conversion methods, bioenergy clearly contributes to sustainability.” 

Gnansounou explains that biomass’s potential is strong despite drawbacks of early methods, so work to optimize the process has continued over decades. Most second-generation conversion methods create biofuels from ligno-cellulosic sources, or non-food biomass, including low-input crops or waste materials. Third-generation biofuels are derived from algae and, most recently, possibilities for bio-hydrogen are being explored. 

“None of these is necessarily free from environmental, social or economic impacts. So, for any project, it is important to fully study the life cycle and evaluate its sustainability,” says Gnansounou, whose multidisciplinary team is developing methods to conduct and optimize sustainability assessments.

Decision-making around bioenergy must account for a variety of elements. “For example, we have to give priority to agronomic uses for organic residue,” says Gnansounou. “We have to consider which is the most efficient conversion method. We must also avoid having a great distance between the collection point, the transformation factory, and the point of use.” 

Impacts on developing countries, whose energy demands will grow proportionally faster in the coming years, must also be considered. “For countries like Nigeria, whose top export is petrol, there will need to be technology transfer and incentives for sustainable energy choices to be realistic,” he says. 

Edgard Gnansounou, head of the school’s Bioenergy and Energy Planning Research Group at EPFL @ Alain Herzog

Biowaste from trash to treasure

Among renewable energy sources, bioenergy is unique in its capacity to optimize the waste cycle while creating energy. Gnansounou explains there is a distinction between what is true “waste” – something that costs to get rid of – and reclaiming organic residues from bioproduction. While both can be involved in bioenergy, his team is interested in the latter.

“As an example, we are currently working with a European consortium on a project to reclaim scraps from tree farming and use it – first for functional food, then as energy to fuel the process and finally, to sell any surplus on the energy market. The aim is to minimize waste, ideally to move to zero waste.”


On the fork

At the other end of the food production value chain, Professor Ardemis Boghossian, Head of EPFL’s Laboratory of Nanobiotechnology in the School of Basic Sciences, is working to tackle retail and consumer food waste with a cutting-edge transformation of food packaging. 

“In our lab, nanobiotechnology is about taking the advantages that we see from biology and combining them with the advantages we see from artificial materials to make hybrids. In the end, both biological and artificial materials are built from the same kinds of atoms, and we can see this at the nanoscale where we are able to merge the different materials. Let’s take the best materials that we have in the world and try to make something that you can’t make if it’s just biological or if it’s just artificial,” Boghossian explains. 


We are currently working with a European consortium on a project to reclaim scraps from tree farming and use it”

Smart packaging to save food

Inspired by the rich community of international researchers at EPFL, she became passionate about the issue of food waste and saw opportunities to address part of the food challenges that the world faces. 

For safety reasons, food expiry dates are very conservative. Use-by dates are conservative so that people don’t risk eating or drinking something dangerous. The downside of this is that many people see an expiration date and throw away perfectly good food, contributing hugely to the problem of food waste. 

Illustration © Patric Sandri

This makes the ability to monitor food in real time very important and using the nano-bio hybrid approach Boghossian’s lab has made a real breakthrough. “We’ve been building sensors that monitor food quality using emitted light. For these sensors, we use nanotubes and wrap them with a biological material, like a protein or DNA, that has very specific interactions with the molecules we are trying to detect from the food. This technology combines the amazing specificity you get with biological materials and the amazing light properties you have with the nanotubes. These sensors can detect gases, for example, important for identifying rotting fruit or meat,” she says. 

We’ve been building sensors that monitor food quality using emitted light”

The microfluidic biosensor © Alain Herzog


They are at a wavelength of light that we can’t see but that goes completely through opaque food packaging. Boghossian’s team has started incorporating them into various poly-mers to compare their performance, while also working towards developing a portable device to scan them and indicate whether the food has expired or not. This could help not only supermarkets and stores to manage their stock, but also consumers at home.

Boghossian says the huge scale of the food waste problem can sometimes become overwhelming, but it’s important to focus on what can be done. “It can be easy to get bogged down to thinking ‘OK, even if I do this, and I do the best I can, the problem is still going to be there,’ but looking at the unsolved problems certainly gives me the motivation to keep going. Every bit of progress helps.”

Back with a focus on the farm, Gnansounou also continues his work on the paradigm shift that will be needed for bioenergy to become more mainstream. “The ecological crisis is a global problem and we need to recognize the chain reaction of our decision-making and act accordingly. We have an imperative to better manage energy demands and move away from fossil fuels. This is a global priority and reclaiming and reutilizing waste for bioenergy is a great way to do that.

The microfluidic biosensor © Alain Herzog

All that glitters

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Sheena Kennedy
There’s a goldmine in our electronic devices – precious metals that are limited resources. Currently, most of this metal is being wasted. Collecting and reusing it can help reduce numerous environmental and human costs.

Your new phone arrives in its sleek packaging, with its tiny folded instructions (in tiny writing and several languages) on how not to dispose of it. You set up the quick transfer for your data and pretty soon, you’re ready to go. If you’re sentimental, perhaps your old phone stays stuffed in a drawer. Otherwise, it may go for recycling … or maybe a landfill.

Nearly one billion cell phones are produced each year, each containing about 50 cents worth of gold. When they get discarded – after an average of about two years – precious metals go in the trash with them. In 2018, 48.5 million tons of e-waste was generated, about 80% of which went to landfills. This translates to more than 10 billion euros of gold lost each year to e-waste. On top of that, this lost gold means more mining, exacerbating high environmental and human costs of current mining practices, including long-term pollution of natural habitats and human exploitation.

“Given the unsustainability of our current behaviors, the concept of a ‘circular economy’ has gained traction,” explains Wendy Queen, Head of the EPFL Laboratory for Functional Inorganic Materials. “Done right, recovering precious metals from e-waste could be more cost-effective than mining.”

There are, however, drawbacks to current methods for recovering these metals from electronics. These rely on pyrometallurgy, with minimal pre-treatment steps. The process is energy-intensive and typically also involves incineration of the plastic components, generating pollution.

“In Switzerland, we like to think we recycle well,” says Queen. “That’s true for some things, like glass, aluminum and PET. About 95% of our e-waste goes to recycling – but only about half the precious metals in it are recovered. We think there’s real potential to do this better. So, two things are important. Firstly, the public needs to become more aware of this issue. Secondly, we need technology that’s effective and more environmentally friendly.” 

Queen’s lab is conducting research into methods using
metal-organic frameworks (MOFs) that offer exciting possibilities for improved extraction. “MOFs are the most porous materials in the world,” explains Queen. “They look like powder, but in fact they’re a lot like sponges, just with incredibly tiny pores – the biggest are about five nanometers, about 50,000 times smaller than the diameter of a human hair. We can design systems to use these microscopic holes to extract a specific type of molecule from complex liquid mixtures. So, in this case, we separate gold from e-waste mixtures.” 

Prof. Wendy Queen, Head of the Laboratory of Functional Inorganic Materials at EPFL @ Alain Herzog

In a 2018 article in the Journal of the American Chemical Society, the lab demonstrated how to use MOFs to extract gold from complex mixtures like water, wastewater, or solutions used to leach gold from e-waste and sewage sludge ash. The MOF composite they use can extract 934 mg gold per gram of composite – and it does this in record time, as little as two minutes, with gold purities of 23.9 karat. 

The lab is continuing this work developing new materials with improved properties for metal extraction. “We’re aiming for scale-up and production of top performing metal extracting MOFs and their incorporation into separation devices,” says Queen. “This will allow us to evaluate the potential of the technology for precious metals recovery from real-world waste streams, including metal solutions generated from electronic waste.” 


A climate code red for humanity

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Tanya Petersen
Can we clean up the atmosphere fast enough to avoid a carbon-driven catastrophe?

Grim reading, a sobering reality check and a code red for humanity – just a few of the dozens of descriptions of last month’s Intergovernmental Panel on Climate Change (IPCC) report, Climate Change 2021: the Physical Science Basis, which showed that scientists are observing changes in the Earth’s climate in every region and across the whole system. Many are unprecedented in thousands, if not hundreds of thousands of years and some are now irreversible.

Julia Schmale is an EPFL scientist who has witnessed some of these changes firsthand. Head of EPFL’s Extreme Environments Research Laboratory, she has conducted research on the Arctic for more than a decade. Her latest projects, CRiceS and MOSAiC, study the key role of sea ice and the atmosphere in the polar and global climate system, bringing together more than 20 international research teams at the forefront of polar and global climate research in Europe, the US, Canada, South Africa, India and Russia. They aim to enhance the physical and chemical understanding of the polar climate systems, and the modeling of the impacts that these regions have on the global climate. Schmale is an atmospheric scientist and investigates how human emissions contribute to warming in polar regions and how this warming changes environmental processes there.

“I first went to Greenland in 2008 to study how air pollution is transported there from the mid-latitudes, and within that time frame I have already seen a change. Two years ago, when we started the MOSAiC ice drift expedition, the sea ice started building up very late. One of the concrete things that you’re looking for, when you want to build a scientific camp on sea ice, is an ice floe that will hold for an entire year – so you really want to make sure it’s thick enough and doesn’t break. That’s becoming trickier. If the sea ice is very thin late in the season, then you need to wait until it’s almost completely dark until you can set up camp. This poses really practical challenges, and you miss out on science earlier in the season, which inhibits us from better understanding Arctic change,” Schmale says. 

The Arctic is warming two to three times faster than the rest of the globe, driven by anthropogenic greenhouse gases. The latest IPCC report says very clearly that we are bound to reach the global warming level of 1.5°C in the next decades, and the Arctic is a sentinel of what could happen in other regions. 

Illustration © Patric Sandri

Putting the carbon back into place

“The sea ice has retreated enormously, the permafrost is thawing, Siberia and Greenland are burning. These are really stark changes,” Schmale highlights. “This very clearly tells us that we need to undertake immediate and large-scale work on removing greenhouse gases and other warming substances from the atmosphere – that is, emitting less CO2 and air pollutants such as soot, and working out how to remove what is already there and will stay there,” she continues. 

Replacing fossil fuels with renewable energy will help to reduce or stop the future emission of greenhouse gases and EPFL’s
Laboratory of Renewable Energy Science and Engineering investigates the conversion of renewable energies into storable fuels, materials and commodities. A special focus lies on novel, solar-driven energy conversion processes based on solar thermal, thermochemical and electrochemical processes.

Since 1751 the world has emitted approximately 1.5 trillion tonnes of CO2 that must rapidly be removed from the atmosphere. Carbon capture and storage will need to be one of the technical solutions we deploy. Professor Lyesse Laloui is Director of EPFL’s Soil Mechanics Laboratory as well as the Civil Engineering Section and has been working on both nuclear waste and carbon storage for more than two decades.

“The idea of storing CO2 in the ground is currently the unique worldwide solution for dealing with large volumes of CO2, and we’re talking about tens of millions of tonnes per year. It’s a very simple process from an engineering perspective because it’s similar to extracting gas or oil. We aim to optimize the CO2 to a supercritical condition, not entirely gas but not entirely liquid, because it decreases its volume by almost 500 times, at the same time as being able to flow like liquid so you can inject it. It’s really a magic situation for us, because it means that we can store huge volumes,” he says.

Laloui and his team research the mechanical integrity of carbon storage options, the volume that can be injected in a given reservoir, the pressures and physical processes that occur when fluid is injected and they develop predictive models for the long-term behavior of the entire system from hundreds to thousands of years. That’s why he will be closely watching a joint Swiss-Icelandic carbon storage demonstration project starting soon in which Swiss CO2 will be captured, transported and then stored and monitored there. 

CO2 will be captured in Switzerland and sent to Iceland – by train to Rotterdam and then by ship, with scientists there monitoring its storage underground,” Laloui explains. “It’s an important project because consortiums in the UK and Norway are already offering ‘empty’ North Sea oil fields to companies and countries as carbon storage sites, for a cost. It’s critical to understand not only the security of the storage but demonstrate how the whole transport chain functions as a process.” 

Laloui has been working on the underground storage of nuclear waste, CO2 and geothermal renewable energy for more than two decades and is pleased that there finally seems to be some momentum to finding real solutions to the global problems we face. “I’ve been feeling the urgency in my work for some time but when I started working on these issues 25 years ago, we were completely at the margins, now, there’s a recognition that this work is important for the whole of society.” 

Since 1751 the world has emitted approximately 1.5 trillion tonnes of CO2”

One atmosphere for all

In the coming decade he would like to focus on building multi-disciplinarity in negative emissions research and technology to speed up the rate of change, as well as focus on renewable energy. “My big hobby is energy geostructures because basically we can create buildings that are almost 100% autonomous from an energy perspective. I will push this solution as much as possible in the next decade. The challenges are huge, but we need to approach things from an optimistic point of view. People are afraid of innovation so it’s not just about technical solutions, it’s about behavior change as well, and that takes time.”

Schmale agrees. “In my heart I’m optimistic, but it’s extremely challenging and we need to get going.” Ultimately, she believes the atmosphere is a powerful symbol of why we need to act quickly and decisively: “Without an atmosphere none of us would breathe, so the concept of this One Atmosphere should remind us that we are one human society on Earth, and we have a responsibility for the planet we live on and each other. This is the Anthropocene where we are facing these grand challenges and I think we can clean up our air, but it will take a huge effort. There is no silver bullet, there are no quick shots. It’s nothing short of transformation.” 

We can create buildings that are almost 100% autonomous from an energy perspective”


Making space a safer place

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Stephanie Parker et Emmanuel Barraud
Space debris put at risk critical space-based infrastructure that supports services such as the internet, global navigation and climate monitoring. EPFL is not only part of the first debris removal mission, but is also assessing policy options to ensure the safe and sustainable use of space.

Human activity in space is accelerating rapidly. In 2020 alone, 1,200 satellites were launched. While there are currently around 4,500 operational satellites in space, there are plans to launch up to 60,000 more in the next decade. Many of these will make up large satellite constellations, which will provide telecommunication services. However, each additional item put into space increases the risk of collision and the potential generation of new pieces of debris. 

Space debris is the term given to any defunct object in space, from items as large as lost or abandoned spacecraft to objects as small as lens caps, bolts and paint flakes. There are currently over 100 million pieces of space debris. Thirty thousand of these are larger than 10 cm and mainly result from collisions and explosions. These pieces of  debris can collide with one another or with active spacecraft, generating more debris. If enough debris are created in a particular orbital region, it could cause a cascade of collisions, threatening the safety of future space operations. 

Illustration © Patric Sandri

Regulations dating from the Cold War 

Cluttered space might not seem like a problem to those of us on the ground, but we rely on space-based infrastructure for many of our vital services, such as communication, navigation, financial transactions and environmental monitoring. However, although the technology that makes this space activity possible is advancing every day, the binding international agreements behind space activity have not evolved. The five United Nations treaties on outer space adopted in the 1960s and 1970s do not directly address the space debris problem. To bridge this gap, nonbinding guidelines have been developed in the past 20 years to limit the creation of new debris and reduce collision risk. However, compliance with these guidelines is low.

This complex risk landscape in an area with insufficient governance has led the EPFL International Risk Governance Center (IRGC) to begin a new project, in collaboration with the EPFL Space Center (eSpace) and Space Innovation, studying the management of risks related to space debris to ensure space sustainability.

“There are many risks inherent to space activity,” said Romain Buchs, IRGC’s scientific assistant and author of the report, Collision risk from space debris: Current status, challenges and response strategies. “But it is important to focus on collision risk, as it is clear this problem is only growing, and there are still not adequate policies, regulations and business models in place to address it.”

There are many risks inherent to space activity

Who will pay? 

“There are many technical options to avoid creating more space debris and reduce collision risk from existing debris, but they can be costly and there are limited incentives to implement them,” said IRGC executive director Marie-Valentine Florin. “Implementing remediation through active debris removal, just-in-time collision avoidance or other techniques requires cooperation between space actors, including a willingness to share costs.”

NASA and ESA, currently the two leading space agencies, are indeed very conscious of the space debris problem. ClearSpace, an EPFL startup, has just been chosen by the European Space Agency to lead the consortium that will deorbit a big piece of space junk: a part of an ESA launcher roughly the size of a washing machine. Scheduled for 2025, the ClearSpace-1 mission will be a stepping stone, demonstrating our ability to address the issue and motivating space actors to act. It will have a significant impact in terms of raising awareness about the space junk problem.

Clearspace One Mission animatique © Clearspace

Make it sustainable

What’s more, it is accompanied by the Sustainable Space Logistics initiative from eSpace, which will undertake research on operating sustainably in space. Founded in 2014, eSpace is expanding and redefining its research priorities. This research initiative is part of the unit’s ambitious plans to become a center of excellence in equipment and data for space exploration, and in the development of lasting, sustainable space infrastructure.

“There’s growing talk in space circles of humankind returning to the Moon and establishing a permanent base there,” says eSpace director Jean-Paul Kneib. “But before we can do that, we need to think long and hard about how we design consumables – energy, fuel, water and food – from the standpoint of both recycling and sustainability.”

Space is no exception to the rule: a massive cleanup must be done up there. But more important still: humanity now has the moral duty to stop filling it with junk-to-be. When talking about orbits, thinking from a circular perspective just seems natural, doesn’t it?

Clearspace One Mission animatique © Clearspace
Interview Robert West

Online cleanup: Getting rid of virtual rubbish

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Tanya Petersen
It’s obvious that we need to clean up the physical world around us, but what about the online environment in which many of us spend an increasing part of our lives? Tanya Petersen spoke to Robert West, Head of the Data Science Lab in EPFL's School of Computer and Communication Sciences, and began by asking him how we should even begin to approach this question.  

“The intersection between physical rubbish and non-rubbish is fairly straightforward”, says Robert West. “Generally, we know that plastic bottles in the ocean or greenhouse gas emissions are polluting our environment, no discussion, we know the problem, let’s go and solve it. It’s not so clear online, so before we even think about cleaning this environment, how do we begin to determine what is trash and what isn’t? One person’s rubbish is another’s dogma, people see things differently and I think we need to be very careful with labels. Clearly, some things are obviously rubbish, they are not true and we can prove it but finding out what is rubbish, or even working out how to decide whether something online is rubbish or not, is a hard problem in general and for every specific piece of content.” 

Do we have any idea how much information online is true and how much isn’t?

At the website level we can say we know that a domain specializes in publishing fake news and then we could check what fraction of web content comes from those domains versus others, but this is just skimming the surface. Most fake content online is like deep ocean rubbish, you don’t even know it’s there and even when you do see it often you don’t know that it’s garbage. There are some attempts to quantify the speed at which rubbish versus truthful information propagates, but overall, it might be impossible to fundamentally quantify what fraction of content online is rubbish. So, cleaning up rubbish online versus cleaning up rubbish in the physical world are rather different problems.

Prof. Robert West, Head of the Data Science Lab in EPFL’s School of Computer and Communication Sciences © Patric Sandri

If we can come up with some definition of online rubbish, how can we incentivize people to identify fake news and other informational trash?

I’ve thought a lot about ways to incentivize and engage large numbers of people, not just fact-checkers who are paid to do this for money, to help solve this problem. Just like campaigns that try to convince citizens to remove garbage around cities so that we all have a good environment, if we could somehow bring these online that would be wonderful. Even so, I think campaigns only go so far. One idea I have had is to put labels on information. In our physical world, for example, we have biohazard labelling. The dangerous material is there, because it has to be somewhere, but people don’t go near it. In the information space you could imagine something similar where if you could label something as having a high probability of being wrong then that would already be useful. However, it still has its limitations and, as for many things, there is no right or wrong, it comes down to opinion. Is Hillary Clinton a liberal? This almost certainly depends on your political perspective. Is football fun? Another subjective question. 

Should it be the responsibility of the big tech companies to undertake the online cleanup work? 

They need to play a part but I think it’s too easy to say it should be their responsibility, because if you say it’s their role to clean up the rubbish, then you also leave the decision to decide whether it’s rubbish or not to those companies. Do we want that and then just accept afterwards that whatever hasn’t been identified as rubbish by them is true by definition? That’s dangerous. 

Cleaning our online world is clearly very complex with lots of both ethical and practical issues to take into consideration. Is it something that might prove just too difficult? 

In comparison to our physical world, it’s a very different game, but that doesn’t mean that all bets are off. If we could begin by identifying and cleaning up the obvious rubbish, that’s a good start because first, it means less rubbish and second, it may have the effect of scaring people away from generating more. It’s a kind of Tragedy of the Commons – if no one cleans up then everyone will throw their rubbish on the pile, so we at least have to do the best that we can to try to end this tragedy.

Do we want that and then just accept afterwards that whatever hasn’t been identified as rubbish by them is true by definition? That’s dangerous.”


Can proteins help us clean the world?

Photo Patric Sandri
Dimensions - EPFL Magazine
Text | Tanya Petersen
“You take a tie, you take a water filter and from them you make a drug: that’s where the future lies.”

It is everywhere and the numbers are mind-blowing. In 1950 the world produced around 2-million tonnes of plastic, which rose to an incredible 360-million tonnes by 2019. By 2050, there will be more plastic by weight in the oceans than fish and it has even been found at the bottom of the Mariana Trench. Of the 8.3-billion tonnes of virgin plastic produced worldwide, only 9% has been recycled and microplastics have been found in places from Arctic snow and Alpine soils to the organs inside our bodies.

Plastic pollution is insidious and it is increasing. “Humanity is refusing to understand that the scale of the problem is such that a lot of small solutions won’t be a solution and solutions that create secondary effects will also not solve the issue,” says EPFL Professor Francesco Stellacci. This is why he has turned his attention to plastic waste, and he has a dream. Head of the Supramolecular Nano-Materials and Interfaces Laboratory within EPFL’s School of Engineering, Stellacci imagines a future in which plastics are made like proteins and, at the end of a product’s life, a “magic” plastic digestor ensures that the material can be used again, and again. A nearly perfect circular economy.

“We need a 180-degree change in order to reverse this. We need behavioral change, we need an economic model that changes completely, and we need new technologies,” he says. “There is a lot happening in recycling, for example, but this won’t solve the problem. We could go completely to bio-sourced plastic but we will need 400-million tonnes of trees, or vegetables, or whatever to produce it. However, nature is also for food, for producing oxygen and it’s critical for biodiversity. There’s competition for land, so where are we going to find all of this biomaterial and where will we put it to biodegrade?”

Contemplating these complex issues, Stellacci pondered what he could contribute from a scientific perspective and began thinking about the magic of proteins. Hundreds of millions of tonnes are produced on Earth every year in a process that is perfectly sustainable. So, what’s the secret?

“Proteins are like necklaces that string many beads, called amino acids, together with each bead a different color. In proteins there are 20 colors and the sequence within the string determines the property,” he explains. “What does nature do with these polymers? For example, when you eat, your body takes this necklace, chops it down into the amino acid beads and then inside your cells a machine called the ribosome puts them back together in a different order, obtaining a new protein which is what your cell needs at that moment.”

Illustration @ Patric Sandri

Illustration @ Patric Sandri
Illustration @ Patric Sandri

This process obeys the key paradigm of a circular economy. The amino acids stay in the system, they are reused and sugar produces new beads to compensate for the inevitable losses in the system. It’s not 100% efficient but it obviously works. Stellacci’s vision is that in future all plastic will be based on this paradigm, where protein-like plastic is thrown away in a major digestive container, it breaks down into beads and is then reconfigured into whatever is needed at the time. 

He refers to this dream as one that is “a few lifetimes away”so the focus is on taking small step after small step. However, under the auspices of a prestigious European Research Council grant, Stellacci and his team recently achieved an exciting breakthrough in their research. 

“We have just shown that we can reconfigure proteins – not in the human body but in the lab. We digested a mixture of proteins and produced a third that has nothing to do with the first two. In this case we took silk used to make ties and beta-lactoglobulin, a by-product of cheese production that can be used to make water filters, digested them together and produced green fluorescent protein, a major biotechnology protein that is an example of a drug.”

The next step for Stellacci and his team is to scale up the process and then make it work for other biological materials, such as DNA. Then, he says, “I need to come up with a brilliant idea on how to translate these to synthetic plastics. I still have another 20 years left in my career and hopefully I’ll get people excited enough so that even when I’m gone, they keep working on this. It is not an improvement on current industrial processes, it is a 180-degree shift on what we’re doing, when plastic becomes truly sustainable. That’s the dream.” 

Illustration @ Patric Sandri

I need to come up with a brilliant idea on how to translate these to synthetic plastics”

Youth on the front line

Between the Fridays for Future movement, climate marches and other ambitious initiatives, it’s clear that many young people born after the year 2000 are worried about the fragile state of our planet and the damaging effects of human activity.

According to a study approved in September for publication in The Lancet Planetary Health, 45% of
16- to 25-year-olds surveyed in ten different countries suffer from eco-anxiety on a daily basis. Nearly two-thirds of the respondents reported feeling very or extremely worried about climate change, and 75% said they thought the future was “frightening.” 

Something must be done, and it’s going to fall largely on the shoulders of that generation. Today’s young people will have the arduous task of coping with the consequences of over a century of economic growth that came too easily, since it was based on cheap yet heavily polluting resources. And they will be called on to develop solutions for restoring humankind’s prospects for a bright future. 

Understanding global issues
EPFL has been giving classes for years to build students’ awareness of the environmental challenge. Called Global Issues classes, they’re taught as part of EPFL’s Social and Human Sciences (SHS) Program and are mandatory for Bachelor’s students. They cover fields ranging from food and energy to the climate and transportation. In other words, every sector where there’s considerable potential for reducing the impact of human activity. “Once our students become aware of the issue, they approach their areas of specialization in a whole new light,” says Pierre Dillenbourg, EPFL’s Associate Vice President for Education. “That opens up avenues for them to leverage their creativity and apply the skills they learn in class to help improve society as a whole.” 

In addition, the diplomas handed out by EPFL include an Archimedean Oath whereby graduates pledge to behave ethically and responsibly towards nature and humankind throughout their careers. The oath was developed by AGEPoly in the 1990s and has since been adopted by other European universities.

Many ways to get involved
Over the past few years, the EPFL community has come up with an array of climate action initiatives. To help people navigate through the different opportunities, two EPFL Bachelor’s students – Carla Schmid and Timothée Hirt – have developed a guide as part of their SHS program. The guide, available in both poster and website format, can be viewed at go.epfl.ch/GuideDurabilite (in French only). The EPFL website also contains an overview of the School’s environmental and sustainability-oriented initiatives, at go.epfl.ch/sustainability.

Now that humanity has reached a tipping point, it’s crucial that we take action through a concerted, planetary effort. This will involve young people, of course, but it is also incumbent upon those who have left the environment in such a sorry state. These older generations need to support the ambitions of today’s young people through both political and economic measures. Together, we can help remedy the errors of the past.