The Engineering Behind a Tap

The production and use of everyday products, such as clothes, bottles, frying pans, cosmetics, medicines, etc., pollute water and this can affect people’s health through the water and food they consume. In this context, we must be prepared to face the planet’s future environmental challenges that will increasingly challenge the maintenance of water quality standards and demand its reuse in a circular economy. Beatrice Cantoni is a researcher at the Department of Civil and Environmental Engineering at Politecnico di Milano. She has won several awards and has received individual funding on these topics. Her research focuses on what happens to emerging contaminants as they pass along the water cycle. On the one hand, one aim is to develop and apply a quantitative chemical risk assessment, since these pollutants have an impact on both human health and the environment. On the other hand, the second aim is to investigate different technologies to reduce these risks in: drinking water, areas of agricultural and potable reuse of treated waste water. Since her PhD, she has been working with various water suppliers, research centres, universities, technology experts and toxicologists to find multidisciplinary solutions in the sustainable management of water resources.

‘Initially, I was more inclined towards mathematical engineering but, after reading the syllabus for environmental engineering, I decided to enrol in the latter,’ the researcher explains. ‘Right from my first Bachelor’s thesis, I realised that my calling was to work on water treatment. Hence, I decided to embark on the PhD route, as part of Professor Manuela Antonelli’s research group, on the issue of treating drinking water to minimise the potential risk to consumer health.

We developed a process that analyses this potential risk that comes with the presence of “emerging contaminants”. These are new contaminants that have only recently been detected in the environment and about which little is known, not only in terms of their potential effect on people’s health, but also on how best to treat them or what level of concentrations to expect in drinking water.

The aim is to reduce the concentrations of these contaminants through multidisciplinary work: I spent most of my time here at Politecnico di Milano, but afterwards I spent some time at the German Environmental Protection Agency (Umwelt Bundesamt, UBA) and the Technical University of Berlin, where we investigated a technology that reduces some of these emerging contaminants. Then I went to Holland, to the KWR (Water Research Institute), a major water research institute in Europe, where we collaborated with toxicologists, technology experts, data analysts, experts from different backgrounds. This allowed me to study the issue from various points of view.

At the end of my PhD, whilst still in the same research group, I broadened my research horizon to include waste water, both civil and industrial, again with the aim of reducing these contaminants but with a focus on the greater reuse of water due to the climate crisis, one need only think of the impact on agriculture and thus on food’.

So your work consists of models but also of experiments in the laboratory

‘In the laboratory, tests are performed on a small scale to see how water is treated at a facility. This allows us to observe more quickly, within a few days, what will happen on a larger scale within several months. Thus, we are able to examine how the treatment works under different conditions in a limited time period.

Then, thanks to simulation modelling, we can predict how it will perform even in situations that we have not been able to test, perhaps because they have not yet occurred but could occur in the future, for example due to climate change.

Speaking of climate crisis and water scarcity, your PhD was funded by Metropolitana Milanese. What is the groundwater like in Milan?

‘In Milan we are very lucky. These contaminants are at very low levels and have no adverse effect on human health, but the research is precisely to understand if and how this situation might develop in the future. Climate change could lead to an increase in contaminant concentrations or a deterioration in groundwater quality. We have to prevent and anticipate these problems, giving providers all the tools they need to manage them.

At outreach events or open days, we ask the public if they have ever thought about where tap water comes from. We often take running water for granted, we are not aware of its engineering, design and treatment and distribution. These are all very well thought out and controlled in real time, so that water is always 100% safe when it is needed but also ready for the future. The environmental engineer is essentially “hidden” inside the tap’.

You are working on the issue of climate change with various research projects. What does that involve?

‘I participated in the launch of the SafeCREW project funded by the European Union under the Horizon Europe calls, a three-year project that started in November which involves several European partners, including my research group and Metropolitana Milanese itself. Its aim is to understand the impact of climate change on available water resources and how we will need to adapt disinfection processes of drinking water in order to minimise any kind of risk: both microbiological and chemical. In fact, we are faced with a trade off: water must be disinfected to reduce microorganisms, but at the same time, by-products could be generated. Managing this process is currently also very well controlled with real-time tools. But this project aims to assess what needs to be done in the future. For example, some German partners do not disinfect water at the moment and follow other strategies, but with climate change they may have to resort to this process, they want to be prepared to understand when and how they will have to act.

Last year I received an Individual Fellowship from AXA Research Fund. The call was specific to the impact of climate change on human health. The project I proposed, and which was selected among 8 funded projects worldwide, analyses how climate change can affect the water cycle and lead to an impact on human health through water and food consumption. We need to understand what we might have to do in the future to minimize the risk.

And risk is what I more specifically deal with in the EU-funded Next-GenerationEU project PNRR RETURN Extended Partnership, which I have been involved in since March 2023. The aim is to develop new techniques to assess, manage and minimise the risk to human health in complex contexts such as the water-food cycle’.

You have been selected to participate in this year’s European Talent Academy. Can you tell us what this involves? 

The European Talent Academy involves some 20 young researchers from three universities: Politecnico di Milano, the Technical University of Munich and Imperial College London. There are eight of us from different Politecnico departments. The topic here is human health as well; from 29 to 31 March we met with other researchers here at our university and each of them presented their own study in order to seek collaborations and propose joint projects amongst the different universities. It is a very useful scheme for young researchers at the beginning of their careers as we are, because the project also includes visits to other universities and their laboratories. It is a very exciting time because issues such as health are addressed with different experts, for example with architects, designers, engineers, doctors, toxicologists’.

Which contaminants are the most studied and monitored at the moment?

‘In the “ranking” I would say PFASs are at the top because regulations on drinking water, waterways and waste water are beginning to include these emerging contaminants in their texts. PFASs are the contaminants used to make waterproof clothes, but also to make non-stick pans. In September, a four-year LIFE-CASCADE project will start in which my research group is involved to assess and reduce the possible contamination of both PFASs and microplastics from textile industries. The aim is to assess whether it is worth working on treatment directly at industry level or in centralised treatment plants that collect water from both factories and our cities.

Another contaminant that we often hear about and that is currently found in European drinking water legislation is bisphenol A (BPA), which is an additive in the production of various materials, especially plastics and resin coatings of metals: we often find “BPA free” written on water bottles because there is more awareness about these pollutants that are also found in receipts and plastic bottles’.

What are some small things we can do?  

‘We need to be informed and consciously choose the products we use. Speaking of drinking water, Italy is the second largest country in the world in terms of bottled water consumption (Source: Report Beverage Marketing Coorporation 2022). At public outreach events, people claim that tap water is too hard or they have doubts about its safety and trust bottled water more. In fact, within the “ASAP! – Acqua Sostenibile Al Politecnico!” project financed by Fondazione Cariplo, through blind tastings of different bottled and tap waters, carried out on more than 50 people, we found that most of the participants have pre-existing biases against tap water that are often not even based on their own tastes, but arise precisely from the fact that they are not aware of the quality control process.

We conducted a study with respect to certain families of these contaminants, used as plasticisers, alkylphenols and phthalates, and observed that although in low concentrations, they are more present in bottled water, because the bottles are made of plastic and are sometimes not stored well, perhaps left in the sun or in unfavourable conditions during transport.  Tap water is 100% constantly monitored, we know where it comes from and what treatment it receives. On top of this, our water consumption is becoming more sustainable as we reduce CO2 emissions from transportation and bottle waste management.

Another way to reduce our impact is through our choice in products, starting with cosmetics and clothes: there are now more and more PFAS-free brands, and if you read the labels well or the INCI for cosmetics, there are charts you can refer to. We also deal with medicines because only a small amount is assimilated in the body, the rest ends up in waste water and consequently in the environment. Here, too, conscious and reduced consumption can make a difference. Other pollutants we deal with are pesticides, for example, all those chemicals used in conventional agriculture that impact not only human health but also the environment. We find them in water and ultimately they find their way back to us through food or drinking water. Choosing food that is grown in a way that respects nature is also a way of protecting our health.

There is no need for scaremongering, but good awareness does no harm: operators are responsible for ensuring safety by not exceeding the limits set for contaminants whose precise effects on health we know are already regulated’.

In Europe we also have quite stringent regulations compared to the rest of the world. 

‘Compared to the rest of the world, the EU is ahead; for example PFASs are already within our law on drinking water treatment and quality, while in the rest of the world they are starting to include them with a longer time frame.

Then there are “watch lists”, which are lists of emerging contaminants to be monitored, on which research has been taking huge steps forward thanks to technology within just a few years. On the one hand, technological development is used to assess their concentrations: in fact, they are present at very low concentrations, like nanogrammes per litre, which is a bit like dissolving a sugar cube in Milan’s Idroscalo. On the other hand, toxicologists are looking into whether these concentrations are dangerous or will be dangerous in the future and whether there are some solutions that are more convenient than others’.

What are your plans for the future?

‘In the future I would like to continue my academic career, I like the combination of research and teaching. Our research has a direct social impact because it gives policy makers the data on which they can then establish legislation, and I would like to be able to have an impact on new horizons as well, knowing that 40% of the world’s population is currently not guaranteed safe drinking water.

For example, Africa was the driving force that made me choose engineering and therefore remains a long-term goal. To date, I am more focused on these contaminants that are more common in industrial areas, in our more “advanced” cities. There are, however, several possibilities to go and interpret what we do now for these contaminants in other contexts because we are seeing a decentralisation of industries that were previously only in the West. We deal with the water pollution that this process brings.

Last year I went to Canada for a few months after my PhD. There, they are studying a technology that treats waste water and reuses it immediately as drinking water, because in communities living in remote areas with increasing water scarcity, it can be a useful technology. Of course it was designed for Canada, but it could be a very useful solution in Africa. Many diseases also stem from a lack of access to safe, continuous drinking water. Our priority is to make water more accessible and safe for everyone’.