Brno scientists are testing use of algae in water purification
Scientists from Mendel University in Brno have cultivated highly efficient algae capable of removing residues of fertilizers and pharmaceuticals—including paracetamol and antibiotics—from water. These algae are grown in specialised bioreactors, and laboratory experiments are yielding promising results.
One of the researchers examining the potential use of algae in wastewater treatment is Jan Veselský from the Faculty of Agronomy at Mendel University. Working in the Environmental Biotechnology Laboratory, he demonstrates a specialised system that utilizes a special container divided into sections, where algae grow on the surface as water flows beneath:
“In each section, there are different algae with different bacterial partners that pick up residues of different pesticides or pharmaceuticals. This is our incubator where we grow the algae, but then, for the actual testing, we'll transfer them to machines that are a little bit bigger.”
The larger bioreactors, used for practical testing, include tanks underneath that circulate water through the algae, enabling repeated purification cycles. Veselský explains:
“Here's the bioreactor, and underneath it is a tank where the partially purified water enters and circulates back up through the pump and flows through the algae again. It can perform hundreds or thousands of cycles, and the whole process can take several days.”
The algae in the bioreactors are supported by a diverse community of bacteria and microscopic fungi, which collaborate to break down contaminants into harmless compounds.
Although scientists are still evaluating the algae's ability to remove heavy metals and antibiotic residues, they have already achieved significant results in breaking down other substances, says Pavel Chaloupský, head of Mendel University's Environmental Biotechnology Laboratory:
“We've experimented with paracetamol, or ibuprofen. And we've seen up to 80% loss over five days. In the case of phosphorus, for example, it goes fast. Within hours we have recorded a 90 to 95 percent loss. With the nitrogen, it's slower. There, we can remove about 80 percent of the substance in about a week.”
The algae system is envisioned as the final stage of wastewater treatment, polishing water before its release into the environment. To further validate the technology, the team plans to test it under real-world conditions in partnership with the town of Židlochovice near Brno. These experiments will be conducted at the town’s wastewater treatment facility in the coming months.
According to experts, similar algae-based technologies are gaining traction in the United States. However, in Europe, this eco-friendly water purification solution remains primarily experimental.
Beyond water purification, the harvested algae could offer additional applications. After treatment, the algae could be used as fuel in biogas plants. If safety tests confirm their viability, they might also serve as an eco-friendly fertilizer.
