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The use of membrane collaboration to improve water quality

The research in membrane technology takes place in close collaboration with a range of industries, including biorefineries, wastewater treatment plants and fish farms, and the aim of the new Center for Membrane Technology is to make the university’s leading competences within the field even more visible to national and international research groups and companies. Head of the center is Associate Professor Morten Lykkegaard Christensen from the Section of Chemistry at the Department of Chemistry and Bioscience.

“We have a total of 15 membrane researchers at different locations at AAU, and we all collaborate with companies, with researchers at other sections and departments at AAU and with research groups around the world. The particular strength of our research is that it spans a variety of aspects of membrane technology, including new membrane processes, membrane crystallization, the development of new ceramic membranes and new process combinations” he explains and adds: “Our approach is interdisciplinary and intersectoral, and we develop membranes for many different contexts. By establishing the new center, we can both consolidate our position of strength and display the overall volume of our work. We hope the center can contribute to our continuous attraction of new researchers and industrial collaborators and to our becoming a leading European center in the field within 10 years.”

Ground-breaking research and world-class phd education

As evidence of AAU’s leading position within membrane technology, Associate Professor Vittorio Boffa, also from the department’s Section of Chemistry, and Associate Professor Peter Roslev, from the Section of Biology and Environmental Science, were in 2017 granted a major project under a highly prestigious EU call. The project, AQUAlity, is a European project funded by the European Union under the Marie Skłodowska-Curie Actions – Innovative Training Networks. In addition to AAU, the project includes companies and research and educational institutions in Italy, Spain, France, Greece, Norway and Turkey. The purpose of the project is to collaborate across disciplines, sectors and national borders to educate 15 PhD students within the field of water purification.

Under this project call, more than 1000 project proposals were submitted, and only 7 percent were funded. Each project takes the shape of a training network and is formed by around 20 research groups and companies. 15 PhD students were selected from 70 applicants, and each PhD student will be based in a country different from their own, as well as go on an extended stay at one of the other research groups

Vittorio Boffa

The basic idea of such Innovative Training Networks is to educate students that are exposed to both an academic and an industrial environment to give them the highest possible chance of employment after they finish their PhD. The aim is to form the next generation of scientists, who have insight and skills from both the research world and the industrial world, as well as an extensive, international professional network that they can utilize in their later career.

In the AQUAlity project, the 15 PhD projects revolve around the removal of micro-pollutants in water. Peter Roslev explains: “In our society, we are continually introducing new chemicals that do something beneficial in one way, but which we are increasingly suspecting of having unwanted consequences for humans, animals or the environment – for instance sunscreen or other personal care products that may end up in surface waters and cause unexpected biological responses. In addition, we see situations where otherwise harmless chemicals appear in combinations where their interaction results in in harmful effects. Therefore, we need new methods for detecting and removing these micro-pollutants before they can do damage”. For this reason, the project partners work across disciplines and sectors, combining membrane technology with advanced oxidation processes, microbiology and toxicology. As such, one of the PhD student at AAU is under the supervision of Vittorio Boffa, who specializes in membrane materials, and one is under the supervision of Peter Roslev, who specializes in toxicology, disinfection and the optimization of biological activity with regards to the purification of drinking water.

Vittorio Boffa explains: “In order to remove micro-pollutants from contaminated water, we need to apply hybrid technologies. Membranes are really good for removing them from the water, but the problem with using membranes is that then you concentrate the micro-pollutants – for instance hormone-disrupting substances. Therefore, my PhD student will work on combining membrane technology with advanced oxidation processes – developed by other research groups in the project – in order to be able to destroy the micro-pollutants, once they are concentrated. She will be working on treating wastewater samples from for instance fish farms, wastewater treatment plants or surface water from polluted lakes, and our hope is that she can optimize the developed methods to a degree so that in the future they can be applied in real systems such as urban waterways or industrial water circuits.”

One such method that is being developed at Aalborg University is a process based on membrane distillation where water permeates through a membrane due to a temperature difference between the two sides of the membrane. The membrane is covered with radicals that are capable of destroying the micro-pollutants above 45 degrees, and so temperature is used in both the process where water is caused to permeate through the membrane and in the subsequent destruction of the pollutants.

Advanced measuring methods for evaluating water quality

In addition to the optimization of membrane-based treatment, the project participants also aim to develop new technologies for the detection and assessment of the micro-pollutants, as well as of the chemicals and substances they may transform into once they are in the environment. At AAU, this part of the project is headed by Peter Roslev. In the framework of the AQUAlity project, a list of 12-15 problematic compounds have been selected, and each PhD student has chosen which specific compounds he/she wants to work with over the course of three years. The compounds include typical chemicals used on an everyday basis in our society, such as pharmaceuticals, pesticides, flame-retardants and additives in plastic materials.

My PhD student is working on developing a range of bioassays – bioanalytical methods – suitable for her selected substances. This will hopefully enable us to measure the effect of these substances and hopefully also measure to what degree some of the membrane and oxidation technologies are capable of removing the substances

Peter Roslev

“These bioassays will then be combined with chemical measurements. The idea is that if we can measure chemically how much of the substance has been removed, we will be able to measure biologically how the effect has been reduced or increased – because it is entirely possible that what can be called the “parent compound” has disappeared from the water, but also that it has generated some intermediate substances instead which may still have an adverse effect on for instance the environment. Hopefully we will be able to determine whether this is the case through these bioassays, because they will be interacting with every substance present in the test sample.”

May contribute to higher drinking water quality

The researchers hope that the methods and technologies developed in the project may contribute to heightening the quality of our drinking water and wastewater in the future – to the benefit of humans, animals and the environment. ”At present, there are two problems: One, that we do not know yet what impact these micro-pollutants will have on the environment, and, two, that we do not have any economic way of removing them. But as we are now developing technologies that are both economic and effective, we hope that we may have an impact on the future policy for water purification” Vittorio Boffa says.

While the issue is highly relevant and on the agenda in many countries, whether they will be implemented widely might in the end depend on the political agenda of each country.

- ”Different countries have different ways of acquiring water for use as drinking water. In some countries, surface water such as rivers or lakes is used, which means that these countries already employ a high level of treatment and purification. In Denmark, we use 100% ground water. This means that we are dependent on – and have politically determined – that the quality of the untreated water must be as high as possible so that we need to treat it as little as possible before it is distributed for consumption. As a result of this, we have very strict legislation on pollution and the use of pesticides in Denmark. In recent years, we have experienced a new challenge, as we detect more and new pesticides – not because they have been recently introduced into the water cycle, but because we are getting better at detecting them. And this means that we may actually have been distributing water to the consumers that contains unexpected micro-pollutants” Peter Roslev says. However, deciding how to solve this problem opens op to a political dilemma: If using new methods and technologies for water purification can ensure that pesticides and other micro-pollutants are completely removed from the water before it reaches the consumers, some might see this as a reason to stop the strict protection of our groundwater.

- “It is an interesting – and current – political discussion. Some politicians are against advanced drinking water treatment, but the fact is that even though Danish drinking water is of a high quality, we could give the consumers even better water by increasing the level of treatment. Today, Danish drinking water is treated as little as possible, and if a water reservoir is polluted, the water from it is diluted with clean water until the pollutants reach the permitted level, whereupon it is distributed to the consumers” Peter Roslev explains and finishes:

- “Perhaps it is better to allow advanced water treatment in the current situation and provide optimal drinking water quality rather than just mixing clean and polluted water. Care should, of course, be taken not to start a “slippery slope” with less pollution control, but we hope that by making new economic and effective technologies like the ones developed in AQUAlity available to politicians, companies, industries and waterworks, we can contribute to solving the current problems and give consumers access to even better water.”