Water is something we all depend on every day. When groundwater and groundwater are polluted, it not only has a major impact on our health, it also affects biodiversity. The use of chemicals has increased in many parts of the world as societies have developed, particularly since the Second World War. A large proportion of these chemicals come from leftover medicines. All these chemicals end up in our waters and this causes problems as the technology of treatment plants has lagged behind. They are built to remove bacteria, not chemicals. New methods are needed to measure chemicals and to clean the water. Today, it can be difficult to find the chemicals in water samples, something that researcher Ola Svahn from Kristianstad University has been trying to improve. Dive into Svahn's interesting research on how different types of carbon can be used to tackle the problem.

CHEMICAL POLLUTANTS FOLLOW THE PATH OF WATER

Increasing chemical pollution of surface and groundwater has largely unknown long-term environmental effects, both on aquatic life and on human health. Without clean freshwater, we cannot ensure biodiversity or our own health, let alone a sustainable food supply. In Sweden, we still have a good supply of high quality freshwater, which we should be careful about.

The earth's freshwater resources have been polluted as the chemical society has grown. Since the end of the Second World War, pollution has accelerated, leading to more than 100,000 chemicals being used in the EU today.

Many of these chemicals circulate in society and can end up as pollutants in rivers, lakes and seas. These include groups of substances such as PFAS and brominated flame retardants. Two other key groups of organic pollutants linked to health and the environment are pharmaceuticals and pesticides. Today, over a thousand pharmaceutical substances are used in medicine and several hundred pesticides in agriculture.

Modern communities collect and treat wastewater through treatment plants before it is discharged. The technology used at the treatment plants dates from the early 20th century. The main aim was to make the water free of infectious bacteria and to reduce eutrophication, which is working well. But the treatment plants were not equipped to remove chemical pollutants. These micro-pollutants will therefore in many cases pass through the three stages of treatment (mechanical, biological and chemical treatment) unaffected into waterways. 

Huseby is located at the gateway to Åsnen. Lake Salen is the closest connecting lake and both Alvesta and Växjö municipality's wastewater reaches it via various watercourses. Alvesta sewage treatment plant discharges its treated wastewater into Hjortsbergaån, which in turn flows into Salen. Växjö sewage treatment plant is located at the Norra Bergundasjön, whose water flows westwards via Helige å and reaches Salen at the level of Os. The situation is not unique to the two municipalities. This is the situation around Sweden - the nearest river or lake has been used to receive treated wastewater. What is unique is that the pollution reaches Åsnen, Sweden's first aquatic national park.

Sample processing - needles in a haystack

Sampling and chemical analysis are required to determine the extent of the discharge into our waters. Common to contaminants from pharmaceuticals is that their concentrations in the environment are relatively low, and that they are designed to be biologically active.

The sample can either be liquid, such as a water sample, or solid, such as bottom sediment from a river or lake, or sludge from a sewage treatment plant. In environmental analysis, the volumes of liquid samples can range from a few millilitres in a sample of incoming water to a treatment plant, to up to a litre in a surface water sample from a lake, leaving even fewer molecules to work with.

Chemical analysis is like looking for needles in a haystack, where the needles are the contaminants and the haystack is water or a solid sample. Finding and determining the number and characteristics of the needles requires a number of steps, which together form an analytical chain. The hunt for the needles always starts with the processing of samples, which has two purposes:

1. Samples are purified and freed from haystacks as reliably and efficiently as possible. 
2. Samples are concentrated so that the number of molecules per unit volume increases.

Both steps lead to increased analytical quality. 

The basic rule is that the sample should be analysed as soon as possible after sampling. Today, water samples are sent between regions and countries to specialised laboratories for analysis. Transporting water samples is inefficient and cumbersome, and also compromises the quality of the analyses if the substances to be analysed degrade during the journey. Subsequent sample processing is also time-consuming and represents the main bottleneck for the analytical laboratory. 

My research has led to a new technique that allows samples to be processed directly in nature or at a site in the immediate vicinity of the sampling site. Simple and reliable. The technology makes water sampling more efficient and expands the possibilities, which improves the quality of the analysis.

Final analysis - substances identified and measured

In environmental analysis, the last part of the analytical chain, the final analysis itself, consists of the two analytical techniques of chromatography and mass spectrometry. The final analysis determines the chemical contaminants present in the samples and the levels of each compound. As the concentrations to be analysed are low, the analytical equipment must be very sensitive. After years of research and development, mass spectrometry has become the natural choice. Mass spectrometry based on electrospray has been used for more than 40 years and had its breakthrough in 1988 when John B. Fenn and his collaborators demonstrated the technique's suitability for ionising biomolecules. His work resulted in the 2002 Nobel Prize in Chemistry.

"Mass spectrometry consists of weighing individual molecules by converting them into ions in a vacuum, and then measuring the response of their trajectories in electric and magnetic fields or both."

John B. Fenn, 1989

When I started doing research on micropollutants, I had limited knowledge of the theory of what is expected to favour or disfavour the ionisation process in electrospray. Probably the majority of researchers in my field did too. Research articles from 2006 to 2016 show that analytical methods have relied on the same theory, resulting in methods with too much of a trade-off, as expressed by the researchers themselves. 

In my research, I have shown the value of alternative ionisation, the so-called "wrong way around ionisation". This has opened up new analytical possibilities, free from chromatographic and mass spectrometric preferences. Without these historical biases, I was able to develop both more sensitive and more reliable analytical methods. If I had been more grounded in the old theory of mass spectrometry, I probably would not have designed the experiments the way I did. Sometimes naivety and curiosity, coupled with a bit of small-minded stubbornness, can be fortunate. The analytical methods have been successfully used in a long series of research and monitoring projects in Sweden and internationally, as well as when advanced treatment in a fourth treatment stage at wastewater treatment plants has been evaluated.

The new fourth purification stage

In a research project between 2015-2019, we investigated whether a fourth treatment stage could filter and remove micro-pollutants from wastewater. The treatment stage consisted of sand and granular activated carbon (GAC). The pilot plant was operated in 40,000 bed volumes, equivalent to 40,000^{m3 of} wastewater, with very good results. For example, the purification rate of diclofenac, the active ingredient in Voltaren, was at least 80% during the test period. 

Activated carbon has a porous structure, and its ability to effectively remove contaminants has proven superior to many other materials. The project's pilot plant contained about 400 kg of activated carbon (AC), equivalent to 1^m3. This is roughly equivalent to a filter area the size of Manhattan! The plant also operated smoothly from a process point of view and its treatment performance exceeded expectations, demonstrating that the technology was ready for full-scale deployment.

The research and development work that preceded the pilot studies showed differences in cleaning efficiency between different types of activated carbon depending on the starting material, manufacturing and activation process. Using innovative analytical techniques, we evaluated the purification performance of different types of carbon to optimise the choice of carbon for the plant. The results showed differences of up to 30% in the purification efficiency between different types of commercial activated carbon. Typically, activated carbon is produced from either hard coal or coconut. Using the technology, we also studied different types of biochar in search of a cheaper product. By chemically modifying ordinary wood pellets, we produced biochar that had almost the same purification performance as activated carbon in the initial experiments. 

In spring 2020, the new fourth treatment stage was ready for a larger context. Sweden's first full-scale plant to treat wastewater with our new filter technology was commissioned in Degeberga, Skåne. We are continuously evaluating and researching the plant, and our knowledge of the properties and function of activated carbon is steadily growing. We are seeing the same good pollutant reduction performance as in the pilot projects. This means that the protected Segeholm river on Österlen, into which the treated water flows, is now virtually free of micro-pollutants.

UNIVERSITY OF KRISTIANSTAD

A university in southern Sweden that educates employable students and contributes to important social development.

We have 14,000 employable students on our 50 programmes and 270 courses. Our primary vision is that our students will be well prepared for the world of work. We are the only university to offer work-based learning (WBL) in all undergraduate programmes, and our students are close to jobs and employable!

It employs around 500 people who work together to train students in professions and industries that need new skills. Our research is closely linked to our courses and is useful in areas such as learning, health, the environment, food and business. Our teaching and research create benefits in our encounters with industry, public organisations and other stakeholders.

Collaboration with the surrounding community is one of Kristianstad University's most important tasks. It is through our interaction with the business community, public organisations and other stakeholders that our teaching and research gain added value.

Our starting point is to use the combined expertise of our researchers, teachers and students to create collaborations that lead to benefits for you, for the university and for society at large.

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