Department Environmental Chemistry

Biotransformation profiling of microbial communities

Removal rates for chemical contaminants have been observed to vary between different wastewater treatment plants.  Particularly, it has been observed that removal often improves with increased sludge age. The two competing hypotheses to explain this phenomenon are (i) increased abundances of nitrifying microorganisms, and (i) increased phylogenetic and functional diversity of the microbial communities. However, evidence for either hypothesis is fragmentary, and it remains unclear what types of compounds and transformations really trend with sludge age. This lack of mechanistic understanding prevents informed discussions about whether and, if so, how biotransformation of contaminants could be improved.

In this subproject of the ERC-funded project PROduCTS, we develop the analytical and experimental tools to characterize activated sludge communities exposed to different gradients (e.g., sludge age, DOC concentrations etc.) with respect to their capacity to carry out different types of biotransformation reactions. To this end, we broadly explore the biotransformation profiles of these communities for a large selection of contaminants that cover the most commonly observed functional groups. We determine biotransformation rates and products and group chemicals according to their observed dependence on experimental gradients to shed more light on the underlying factors of biotransformation variability.

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Dr. David Johnson Group Leader Tel. +41 58 765 5520 Send Mail