Medications, cosmetics, and everyday chemicals disappear from our homes into the trash. But they don’t disappear completely. They often end up in the water. And from there, they can have a long-term impact on rivers, the life within them, and our own lives. Luboš Mrkva from CXI TUL led the MIKROP project, which sought to remove these invisible substances from the water before they return to people.
Nanograms. Such a tiny amount that it’s hard to even imagine. Yet it is precisely in such doses that residues of medications, cosmetics, or common chemicals appear in water. They are called micropollutants.
“Compared to ordinary pollution, it’s a negligible amount,” says Luboš Mrkva of the Department of Environmental Technology at CXI TUL. But here’s the catch: a negligible amount doesn’t mean a negligible problem.
These substances accumulate in water and harm everything that lives in it and drinks from it. Ultimately, they can even find their way back to humans.
“Pollution from waterways can find its way back into the human body through water treatment plants. That’s because micropollutants end up in both surface and groundwater sources of drinking water,” explains Luboš.
A wastewater treatment plant isn’t a magic solution. The processes must be properly configured.
Europe is already responding to the problem. New regulations require large wastewater treatment plants to begin removing micropollutants, effective in 2045. But saying “remove them” is one thing; figuring out how to do so effectively and at a reasonable cost is another.
This is precisely what Luboš’s MIKROP project addressed, which he developed in collaboration with Pražské vodovody a kanalizace, a.s. The goal was to improve the operation of municipal treatment plants so that they could remove even substances that standard treatment processes fail to capture.
Micropollutants can be broken down using ozone, hydrogen peroxide, or UV radiation—all of which can be used for advanced water treatment, a process known among water treatment professionals as the “quaternary treatment stage.” Luboš experimented with fine-tuning these technologies to make them affordable. The result is a compact pilot-scale unit that treats approximately three cubic meters of water per hour. Inside, you can switch between different purification methods. At the end of the process, an activated carbon filter helps complete the treatment.
Purification as a Relay Race
But that’s not all. Luboš’s team didn’t just focus on the final step of purification. They viewed the treatment plant as a relay race. Every leg must function properly. If the initial technology passes on poorly treated water, the final runner can’t work miracles.
If the water is still too dirty before the final treatment—that is, full of dissolved organic substances—the expensive technology will be wasted on ordinary impurities. And that’s a problem. These methods aren’t selective. They can’t tell the difference between a hazardous substance and ordinary dirt. They react with any organic matter they find in the water.
“That’s why we tried to ensure that the water entering this final stage was as clean as possible,” Luboš summarizes.
Cheaper Water? It Can Be Optimized
The team had a two-line treatment plant at their disposal. One line operated normally. The other served as a test facility. The researchers adjusted its settings to prepare the water as effectively as possible for quaternary treatment.
The project therefore delivers proven technology. However, every treatment plant is different. Every municipality has different sources of pollution. That’s why this proven technology is a great starting point. It shows how to configure the treatment plant so that as few organic substances as possible enter the final treatment step.
The Polluter Pays
The most expensive part of the entire process is activated carbon. It acts as a final safety net, capturing substances that the previous steps failed to remove. That is precisely why Luboš strives to remove as many organic substances as possible earlier on, so that the carbon’s capacity isn’t exhausted too soon.
Replenishing it is costly. In the Czech Republic, only a few companies handle this, and the carbon must be transported. In some cases, it can account for up to two-thirds of the operating costs of the final treatment stage.
And these costs are passed on to the price of water.
European regulations are based on the “polluter pays” principle. Companies that manufacture medicines or cosmetics should also contribute. Exactly how this will work remains to be seen. But it’s also up to each of us not to waste cosmetics and medicines that will end up in wastewater.
Gone, but Not Gone
Measurements may show that a substance has disappeared. But that doesn’t necessarily mean the water is completely safe. Some substances do not break down completely during treatment. They simply split into smaller parts. The instrument then can no longer detect the original substance. And we currently know very little about these residues.
That’s why Luboš’s team wants to continue their work. They’ll be interested not only in what the instruments measure, but also in how the treated water affects living organisms.