Department Environmental Chemistry

A large number and variety of chemicals used in households, healthcare, industry or agriculture enter our wastewater treatment plants with the domestic and industrial wastewater. In the biological section of the wastewater treatment plants, some of these compounds can be degraded well, while others reach our rivers with the treated wastewater. There, the chemical substances can potentially be further degraded by microbial communities in the riverbed, but some substances can harm aquatic organisms or pollute drinking water sources through riverbed infiltration. Very little is yet known about which microorganisms and enzyme systems are crucial for the degradation of chemicals, which makes it impossible to specifically improve their degradation.

The overall goal of this project, jointly funded by SNSF and DFG, is to achieve a generalizable understanding of the degradation of pollutants by microbial communities in wastewater treatment plants and rivers. Specifically, we will (i) investigate for over 200 different substances that widely vary in their chemical structure how they are degraded in different WWTPs and river biofilms. At the same time, we will (ii) characterize the WWTPs and river biofilms in terms of the microorganisms present and their enzyme systems. From the synopsis of these results, we will (iii) derive hypotheses as to which enzyme systems are significantly involved in pollutant degradation and seek to confirm this with biochemical laboratory experiments. We expect to define substances, microorganisms and/or enzymes that can be used as indicators of the pollutant degradation capacity of microbial communities. All experimental data will be made available to the international research community for further data analysis through publicly available databases, including our own microbial pollutant degradation database envipath.org.

With our work, we hope to take a major step toward a better mechanistic understanding of chemical degradation in natural microbial communities. This understanding is necessary to enable engineering innovations in biological wastewater treatment, and to deliberately target more degradable substances in the industrial development of new chemicals. Overall, our research should contribute to a reduction in the degradation of the environment by potentially toxic chemical substances.