BETA TC presents the results of Llavor project from AGAUR to improve wastewater treatment in urban wastewater treatment plants

In small towns with fewer than 10,000 inhabitants, strict control of wastewater discharges is not mandatory, which increases river pollution and the impact on river and neighboring ecosystems. This pollution can be caused by excess nutrients such as nitrogen and phosphorus, the presence of pharmaceuticals and cosmetics, or the emergence of antibiotic-resistant bacteria. Wastewater treatment plants in these towns do not require specific treatments to remove these pollutants, and tertiary treatment, which would improve treatment efficiency, is often not applied. For this reason, the LEMNAFILMS project of the UVic – UCC BETA Technological Center, led by Lluís Bertrans and other researchers from the Applied Ecology and Global Change team, explores Nature-Based Solutions (NBS) such as the combination of Lemna sp. and freshwater biofilms as a low-cost alternative to treat this wastewater.

Nature-Based Solutions (NBS)

Nature-Based Solutions (NBS) leverage natural processes to address environmental challenges, benefiting both society and ecosystems. In wastewater treatment, this includes reactors and constructed wetlands that mimic natural biological communities to remove nutrients and contaminants such as pharmaceuticals and pesticides.

The project studies Lemna sp. or duckweed (NBS). A rapidly reproducing floating aquatic plant that can absorb nutrients such as nitrogen and phosphorus, as well as heavy metals. In wastewater treatment, it helps reduce nutrient pollution, improving water quality and preventing eutrophication—an excess and imbalance of nutrients that induces algal blooms in aquatic ecosystems. Eutrophication triggers a series of chain reactions with serious consequences, such as a lack of oxygen, which leads to the increased death of life forms, such as fish.

Freshwater biofilms are another NBS that is also part of the research. Biofilms act as natural filtration systems in wastewater treatment, as they are formed by communities of microorganisms (bacteria, fungi, and algae) that adhere to submerged surfaces. These microorganisms decompose and assimilate nutrients, as well as other contaminants such as pharmaceuticals, heavy metals, and pesticides. Furthermore, biofilms help eliminate pathogens and improve water quality, contributing to more efficient and cost-effective wastewater treatment.

Reclaimed water for lettuce crops

Once the water leaves the treatment plant, it passes through this NBS system based on duckweed and biofilm. Research is being conducted to determine whether this water could be used as reclaimed water for irrigating crops such as lettuce. Research is being conducted to determine whether lettuce is capable of growing and does not contain pathogens on its leaves. The ultimate goal would be for this water to be suitable for human consumption. Reclaimed water is water that, after undergoing a treatment and purification process, can be reused for various purposes, such as irrigation, industry, cleaning, or, in some cases, even human consumption.

BETA TC is currently evaluating nutrients in these wastewaters as well as pathogens such as Escherichia coli, Salmonella, and Legionella. The CSIC’s Institute for Environmental Diagnosis and Water Studies (IDAEA), which collaborates with BETA TC, is conducting the study of emerging contaminants such as pharmaceuticals and pesticides. The company Depuradores d’Osona has also provided support throughout the project, providing guidance and recommendations based on its experience and needs in the field of water treatment.

Llavor project from AGAUR

An AGAUR (University and Research Grant Management Agency) Llavor project is a grant designed to finance early-stage R&D projects with high potential for innovation and knowledge transfer to the market. The goal is to promote innovative ideas emerging from Catalan universities and research centers, fostering their valorization and applicability in the socioeconomic environment. These grants cover feasibility studies, proofs of concept, and initial technological demonstrations, helping to mature projects that could become patents, spin- offs, or useful solutions for industry.

This research led by BETA TC represents an important step toward sustainable and innovative solutions for water management in small communities, with great potential to improve environmental and human health.