Mitigating pharmaceutical loads in municipal effluent waters: R&D solutions at Aquafin
During the last 20 years there was an increasing attention and a worldwide concern towards several Pharmaceutical Active Compounds (PhACs) which have been found in water bodies. The effluent of wastewater treatment plants (WWTPs) is a main source of PhACs in the aquatic environment. In fact, most WWTPs are designed to comply with conventional pollutant thresholds such as nutrients, organic matter and solids, but cannot thoroughly eliminate organic compounds at low concentrations ranging from ng/L to µg/L. Adsorption by activated carbon (PAC) and ozonation are currently the recommended technologies for micropollutant abatement. However, in order for more cost efficient technologies Aquafin has been working since 2008 on the development of two new approaches.
The “BioMac” Approach
Biofilm on the GAC
The Biomac process developed by Aquafin R&D includes a granular activated carbon (GAC) filter step followed by a ultrafiltration (UF) step (Weemaes et al., 2011). The purpose of the UF polishing step is to prevent GAC granules and biomass exiting. The process shows stable removal performances (80-90%) for a broad range of PhACs.
Recent research also shows that the biofilm growing on the GAC is clearly contributing (up to 20%) to the degradation of some compounds (Sbardella et al., not yet published).
the “Bio-Inoculation” Approach
Microorganisms conditioned for the removal and degradation of specific PhACs have been inoculated in municipal membrane bioreactors (MBRs) (Fenu et al., 2015-2018). Bio-augmentation experiments were conducted with two different microorganisms:
- Microbacterium strain br.1, for the degradation of sulfamethoxazole,
- Phoma sp. for the degradation of carbamazepine and diclofenac.
The pilot scale MBR was operated in two configurations: treating MBR permeate (post treatment) and treating raw municipal wastewater. The operating conditions of the pilot MBR were optimized based on the results of batch tests and subjected to the limitations of practical application. The most interesting results were obtained with the fungal biomass, achieving up to 40% removal of carbamazepine (CBZ) after secondary treatment (second blue arrow in figure below).
- Sbardella L., Fenu A., Weemaes M., Comas Q., Rodriguez-Roda I., 2018, Advanced biological activated carbon filter for removing pharmaceutically active compounds from treated wastewater. Submitted to ‘Science of the Total Environment’.
- Fenu A., Donckels B. M. R., Beffa T., Bemfohr C., Weemaes M., 2015, Evaluating the application of microbacterium sp. Strain BR1 for the removal of sulfamethoxazole in full-scale membrane bioreactors. Water Science and Technology, 72, 10, 1754-1761.
- Fenu A., Hoffmann U., Beffa T., Bemfohr C., Weemaes M., Schlosser D., 2018, Evaluating the application of Phoma sp. for the removal of Carbamazepine and Diclofenac in full-scale membrane bioreactors. Submitted to Water Science and Technology.
- Weemaes M., Fink G., Lachmund C., Magdeburg A., Stalter D., Thoeye C. Van De Steene B., 2011, Removal of micro-pollutants in WWTP effluent by biological assisted membrane carbon filtration (BioMAC). Water Science and Technology, 63, 1, 72-79. Sbardella L., Fenu A., Comas J., Rodriguez-Roda I. and Weemaes M.. Removal of Pharmaceuticals from WWTPs secondary Effluent with Biofilters. Oral presentation at “Frontiers in Wastewater Treatment and Modelling”, Palermo, Italy (May 2017), IWA.
- Fenu A. and Weemaes M.. Up-scaling of a full-scale municipal fungal membrane bioreactor for the degradation of Carbamazepine and Diclofenac. Oral presentation at 18th International EWA Symposium “Challenges arising from Micro-Pollutants in Wastewater, Water, and Environment”, 1-2 June 2016, Munich (Germany).