"We always find trace substances"

Jörg Rinklebe, professor of soil and groundwater management on drug residues and germs in our waters and the fourth treatment stage in German sewage treatment plants

The quality of the Wupper water is good, but ...

When asked, would you agree with the sentence: "The quality of the Wupper water is good", the renowned scientist Jörg Rinklebe promptly says: "Yes, the quality is basically good, but there are still improvements towards very good and excellent." And this is mainly due to Wuppertal's industrial history. With the founding of the Wupper Association in the 1930s and the development of modern wastewater treatment plants, the water quality has improved considerably over the past decades, when all kinds of industrial wastewater still discoloured the Wupper blue, green or red. "The problem back then was that many of these substances were first absorbed and retained by the soil. Then you didn't notice these effects for a long time. We call this the soil acting as a sink for pollutants because it absorbs them like a sponge. And now, thanks to policy and good technologies, the discharge of harmful substances into the Wupper has been minimised, which has significantly improved the water quality." But this also has consequences, because, the expert explains, we now have the phenomenon of clean water flowing through these dirty soils, so that the soils suddenly act as a source of pollutants. "Many pollutants that are still in the contaminated soil are now being released and are then back in the water."

German wastewater treatment plants - the fourth purification stage

Around 85 per cent of pharmaceutical residues released into the environment come from human excrement. The Rheinische Post already ran the headline in 2024: Sewage treatment plants at the limit - water in NRW contaminated by medicines and germs. Rinklebe knows the reasons why sewage treatment plants are unable to get to grips with the problem and says: "Sewage treatment plants were designed many decades ago. Back then, we simply weren't confronted with these problems to such an extent. There were three treatment stages and they were able to get to grips with the problems of the time very well." But society has also evolved and the consumption of medicines has increased. "In addition, there are antibiotics, hormones and hospital germs, as well as wastewater from the chemical industry, in other words a lot of harmful substances that end up in the wastewater," he explains, "and that's why we are working on the fourth purification stage in the wastewater treatment plants."

The pathogenic cycle

To understand why a fourth purification stage is so immensely important, Rinklebe describes the possible effects of ignoring the situation. "If the pollutants are simply released into the environment unfiltered, they end up in surface water, groundwater, plants and animals, ultimately entering the food chain and finally ending up back in us humans, which would have devastating effects on human health." These substances are often also transformation products that can cause damage to the human body. And the spiral continues, because these pollutants can also bind in the environment in water, soil, plants and animals.

Results of long research paths wait years for authorisation

To date, there are no binding standards for pharmaceutical substances even in the Surface Waters Ordinance, although it is known that substances such as the painkiller and anti-inflammatory agent diclofenac and the anti-epileptic drug gabapentin in particular have an impact on living organisms. Rinklebe explains that the difficult thing with all laws and regulations is that you can only create rules if you are able to comply with them. However, promising projects are already being implemented. The researcher explains: "There are now over 50 pilot sewage treatment plants in Germany that have established the fourth treatment stage. We are already in a good process. There is also a lot of research and conferences on the subject, the main question being: How can I get all these trace substances and trace elements under control?" Various techniques are already being tested. These include membrane techniques and projects with activated carbon as well as ozonisation (ozonisation is a process of sterilisation and disinfection by adding ozone, editor's note). However, the scientist emphasises: "Knowledge alone is not enough to make a law out of it. You first need a scientific basis so that you can formulate a law and limit values in the first place. And the basis must then apply to the whole of Germany. That's why such laws take so long. I know this from soil and groundwater legislation, which sometimes takes 10 to 20 years. Of course, we also need a certain amount of time to derive solid limit values, because these limit value issues always have to be scientifically sound and not everything that is toxicological can then also be implemented in practice. But once this scientific basis is in place, it still takes far too long in the bureaucratic process. And we definitely need to speed up these processes."

Hospital wastewater - an unspoken source of danger

Hospital wastewater is a significant source of antibiotic-resistant or multi-resistant bacteria. However, there are still no legal requirements for wastewater from hospitals. "In my view, this is totally overdue," says Rinklebe, knowing that the costs cannot be borne by the hospital alone. "But perhaps there are other political solutions, because we are not doing our own health or the health of the environment any favours if we allow such harmful substances to enter the environment unchecked. From my point of view, it is absolutely necessary worldwide, as shown by examples from China and India, where many medicines are produced for us. In India, there are many areas where we already know that the environment is being disturbed by hospital wastewater on a gigantic scale." And here too, X-ray contrast media, antibiotics, hormones and germs, as well as anti-cancer agents and disinfectants and cleaning agents are released into the environment via normal hospital wastewater. "In my view, hospitals need separate regulations and separate technology," the expert demands.

Taking recourse against pharmaceutical companies

The polluters, i.e. pharmaceutical companies and the chemical industry, do not seem to be aware of the problem. However, the soil and groundwater expert sees a trend here. "There are now activities across Europe. The aim is also to hold the polluters liable, or at least make them share the follow-up costs. This is an essential step that has so far been missing in our society. Often it is only assessed from a business perspective and not whether natural resources are being used that should be paid for. As a rule, the taxpayer then takes over." This can be seen in the examples of nuclear power plants or the environmental damage caused by corporations. In fact, these consequential costs should always be passed back to the polluter. "Then the product becomes more expensive, but that's the only way to achieve a circular economy and sustainability if I'm serious about it. The big companies will certainly resist, because it means minimising profits, but I'm sure it will be the way forward."

Long-term studies despite harmlessness?

The concentration of pollutants in water is harmless to humans. Nevertheless, long-term studies are being carried out. "Long-term studies are always important, especially in the field, because problems are often underestimated if you only carry out short-term studies," explains the scientist. Long-term studies focus on the effects on the genome, adaptation in the human body or the effects on functional relationships in the ecosystem, for example. "One is connected to the other, but this may not have been researched before. Long-term studies are therefore extremely important in order to detect new correlations and also rule out risks."

Resource priorities are changing in world affairs

The upgrade of sewage treatment plants with a fourth purification stage is planned by 2039. The long timeframe is explained by the fact that cities with a population of over 100,000 are first in line. "But it's still taking far too long," emphasises Rinklebe and says: "The problem is that a lot of resources are being channelled into other areas. We have it in front of our eyes. Many resources go to war and not to education and research or to such important environmental problems. We now have over 50 pilot plants, but we need to be even faster." The researcher does not want to be frustrated by the many processes that take too long and concludes: "I am already a few years older and can see the progress that has been made in recent decades. When I was young, I was very frustrated, but then I also realised that our own work, for example in the amendment of the Federal Soil Protection Ordinance, sometimes takes 10 or 20 years before it is established. But in the end they are established. And then I enjoy the positive things. The staying power has paid off and that is always my hope. I am sure that in 20 years there will be many more hospital wastewater treatment plants or plants for treating hospital wastewater, that we will then have established the fourth stage of wastewater treatment plants."

By the way...
The introduction of the fourth treatment stage at the Wuppertal-Buchenhofen wastewater treatment plant is planned as a long-term project to reduce trace substances.

Uwe Blass

Univ. prof. mult. Jörg Rinklebe has been Professor of Soil and Groundwater Management at the University of Wuppertal since 2006. He is recognised worldwide as one of the most influential scientists in his field. His work is cited very frequently, which is why he was named a "Highly Cited Researcher". He is ranked 4th in the world rankings for environmental sciences and 1st worldwide in the field of soil contamination research, although only a few German scientists have ever been listed in the top 100. From 1997 to 2006, he worked as a scientist, research assistant and project manager in the Soil Research Section of the UFZ Environmental Research Centre Leipzig-Halle GmbH in Halle. He studied ecology for a year at the University of Edinburgh in Scotland (UK). He studied agriculture at Martin Luther University in Halle-Wittenberg, specialising in soil science and plant nutrition.