Removal of residual pharmaceuticals in waste water by catalytic ozonation technology

Pharmaceuticals in wastewater are not efficiently removed by conventional wastewater treatment technologies, leading to their continuous release into aquatic environments. Advanced oxidation processes (AOPs), particularly ozonation and catalytic ozonation, have therefore gained increasing attention as promising treatment options for the removal of these persistent micropollutants.

This research project focuses on the degradation and transformation of pharmaceuticals in aqueous systems using both catalytic and non-catalytic ozonation. The work initially targeted individual active pharmaceutical ingredients (APIs) such as ibuprofen, diclofenac, carbamazepine, sulfadiazine, metoprolol, and naproxen, combining experimental ozonation studies with detailed identification and quantification of transformation products. In-house heterogeneous catalysts have been designed, synthesized, and thoroughly characterized, and their influence on reaction kinetics, ozone utilization, and by-product formation has been systematically evaluated.

Over time, the project has expanded beyond single-compound systems toward pharmaceutical mixtures, competitive effects, and real wastewater matrices, reflecting more realistic environmental conditions. Recent research emphasizes multi-component systems, mineralization efficiency, catalyst stability, and structure–activity relationships, as well as the transition from batch and semi-batch experiments toward continuous reactor concepts relevant for wastewater treatment applications.

A strong emphasis is placed on understanding reaction mechanisms and transformation pathways through advanced analytical techniques (LC-MS, HRMS, NMR) combined with kinetic and mathematical modeling, enabling mechanistic interpretation of observed degradation behavior and by-product formation.

The project has resulted in numerous peer-reviewed publications and two completed doctoral theses (2020 and 2021), and it continues to evolve through new collaborations, master’s and bachelor’s theses, and applied research initiatives. Current activities focus on catalytic ozonation of pharmaceutical mixtures, treatment of real wastewater samples, and process-relevant evaluation of efficiency, selectivity, and sustainability.

The research has been supported by several funding bodies, including Liedon Säästöpankkisäätiö (2024) and Svenska litteratursällskapet i Finland (2025-), and Maa- ja vesitekniikan tuki ry, among others.

Many medicines that we use every day are not fully removed when wastewater is treated. As a result, small amounts of pharmaceuticals end up in rivers, lakes, and coastal waters, where they can harm aquatic life and contribute to long-term environmental risks.

In this project, we study how advanced water treatment methods based on ozone can break down these pharmaceutical residues more efficiently. We also investigate how specially designed solid materials (catalysts) can make the process faster, more effective, and safer by reducing the formation of harmful by-products.

Our research has shown that treating several pharmaceuticals at the same time — as they occur in real wastewater — is much more complex than treating them one by one. We therefore focus on realistic mixtures and real wastewater samples, aiming to develop treatment solutions that work under practical conditions.

The long-term goal of the project is to support cleaner water, healthier aquatic ecosystems, and more sustainable wastewater treatment technologies.

Pharmaceuticals persist through conventional wastewater treatment.

Catalytic ozonation improves degradation efficiency and ozone utilization.

Mixtures of pharmaceuticals show strong competitive effects compared to single compounds.

Catalyst structure strongly influences degradation pathways and by-product formation.