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Designing new technical wastewater treatment solutions targeted for organic micropollutant biodegradation, by understanding enzymatic pathways and assessing detoxification

Final Report Summary - ATHENE (Designing new technical wastewater treatment solutions targeted for organic micropollutant biodegradation, by understanding enzymatic pathways and assessing detoxification)

ATHENE focused on biological degradation of organic micropollutants by mixed microbial populations in municipal wastewater treatment. The interdisciplinary approach of ATHENE combined process engineering, analytical chemistry, molecular biology and (eco-)toxicology, with the aim of better understanding of how micropollutant degradation occurs, what boundary conditions are required to make it happen and to which extent improvement in process design is feasible. Finally, a contribution is made on new methods for a comprehensive assessment of effluent water quality.

Methodologies for process evaluation:
Chemical target analysis of emerging micropollutants as well as newly developed non-target approaches considering thousands of potential micropollutants and TPs were complemented by assessing detoxification using a broad set of in vitro bioassays and in vivo tests. A complete non-target analysis workflow for evaluating different wastewater treatment processes was developed. Moreover, the formation and the removal of TPs can be assessed. Individual TPs have been identified for more than 15 emerging micropollutants and were quantified with the target compounds in pilot plants as well as in full-scale WWTPs.

Methodologies to understand microbial transformation of micropollutants:
A novel method for the extraction of native micropollutant degrading enzymes from sewage sludge has been successfully developed. This is the first time that activities of the enzyme pool of sewage sludge can be directly studied with extracted proteins and provides the basis for further investigations of micropollutant biodegradation via native enzymes in a solution of reduced complexity, facilitating downstream protein analysis by (meta-)proteomics approaches. However, the quantity and activity of extracted enzymes was not sufficient for the recovery of the full variety of indigenous enzymatic activities. Therefore, complementary metagenomics methods were developed to correlate the (functional) genetic composition of the microbial community with treatment conditions. Furthermore, micro-autoradiography was successfully combined with fluorescent in situ hybridization (MAR-FISH) to identify microorganisms involved in the degradation of certain micropollutants.

Innovative biological wastewater treatment schemes:
A set of methodologies was developed to elucidate microbial transformation of micropollutants occurring in wastewater treatment under anaerobic conditions (e.g. iron-reducing, sulfate-reducing) and under aerobic conditions (e.g. cascaded reactors, suspended vs. biofilm systems, substrate limitations). The results indicate that the degradation of organic compounds at low concentrations is provided by a multitude of metabolic specialists performing different transformation reactions. The various degradation steps are at first sight randomly combined, forming a multitude of TPs. Non-target analysis as well as ecotoxicological tests indicate that multi-stage treatment schemes further reduce effluent pollutant loads as well as its ecotoxicity. The major players in nutrient elimination (e.g. nitrifying microorganisms) are responsible for metabolizing only a minority of compounds.
This metabolic complexity means that processes can be designed for enhanced biological degradation of specific compounds (e.g. combined anaerobic/aerobic for de-iodination of X-ray contrast media) as they have the potential to contribute complementary pathways relevant for micropollutant degradation. For mixtures as typically occurring in municipal wastewater the best strategy is to maximize microbial diversity in multi-staged processes. Cascaded hybrid biofilm systems have been confirmed to reliably remove additional compounds of toxic relevance (e.g. diclofenac). Nevertheless, to achieve the removal of the majority of micropollutants a post-treatment such as activated carbon filtration is required in addition to biological processes

Project information

Grant agreement ID: 267897


Closed project

  • Start date

    1 April 2011

  • End date

    31 March 2017

Funded under:


  • Overall budget:

    € 3 473 400

  • EU contribution

    € 3 473 400

Hosted by:

Bundesanstalt fuer Gewaesserkunde