Bioremediation of emerging micropollutants in irrigation water. The alternative of microalgae-based treatments

The present study evaluated the efficiency of a semi-closed horizontal tubular photobioreactor (PBR) at demonstrative scale to remove a total of 35 target compounds, including benzotriazoles, benzophenones, antibiotics and different pharmaceuticals present in irrigation water in a peri-urban rural area. This water run through an open channel and was a mixture of reclaimed wastewater from a nearby wastewater treatment plant (WWTP) and run-off from the different agricultural fields in the area. Most of the compounds studied are usually not fully eliminated during conventional wastewater treatment, which justifies the need to investigate alternative treatment strategies. A total of 21 of these compounds were detected in the irrigation water. Benzotriazoles were only partially removed after the microalgae treatment, with elimination rates similar to those of conventional WWTPs. The UV filter benzophenone-3 (BP3) showed variable removals, ranging from no elimination to 51%, whereas 4-methylbenzilidenecamphor (4MBC) was completely eliminated. Regarding pharmaceuticals, average removals were higher, in the range of 60–100%, with the exception of the antibiotics sulfamethoxazole (46%) and sulfapyridine, which was not removed. Despite the low biomass productivity of the PBR, parameters such as the size of the reactors, the specific mixed cultures developed and the high temperatures and pH in the closed system may account for the overall good results, The efficiency and sustainability of these systems make them a solid, feasible treatment choice.This research was funded by European Union's Horizon 2020 research and innovation program within the framework of the INCOVER project (GA 689242), by the Spanish Ministry of Science, Innovation and Universities (MCIU), Research National Agency (AEI) and European Regional Development Fund (FEDER) [AL4BIO, RTI2018-099495-B-C21]. The GEMMA-UPC group would like to acknowledge the Government of Catalonia (Consolidated Research Group 2017 SGR 1029). Lucas Vassalle would like to acknowledge the CNPQ for his scholarship 204026/2018-0. M.J. García-Galán, E. Uggetti and R. Díez-Montero would like to thank the Spanish Ministry of Economy and Competitiveness for their research grants (IJCI-2017-34601, RYC2018-025514-I and FJCI-2016-30997, respectively). M.S. Díaz-Cruz would like to acknowledge the Generalitat de Catalunya Water and Soil Quality Unit 2017-SGR-1404

Bioremediation of emerging micropollutants in irrigation water: the alternative of microalgae-based treatments

The present study evaluated the efficiency of a semi-closed horizontal tubular photobioreactor (PBR) at demonstrative scale to remove a total of 35 target compounds, including benzotriazoles, benzophenones, antibiotics and different pharmaceuticals present in irrigation water in a peri-urban rural area. This water run through an open channel and was a mixture of reclaimed wastewater from a nearby wastewater treatment plant (WWTP) and run-off from the different agricultural fields in the area. Most of the compounds studied are usually not fully eliminated during conventional wastewater treatment, which justifies the need to investigate alternative treatment strategies. A total of 21 of these compounds were detected in the irrigation water. Benzotriazoles were only partially removed after the microalgae treatment, with elimination rates similar to those of conventional WWTPs. The UV filter benzophenone-3 (BP3) showed variable removals, ranging from no elimination to 51%, whereas 4-methylbenzilidenecamphor (4MBC) was completely eliminated. Regarding pharmaceuticals, average removals were higher, in the range of 60–100%, with the exception of the antibiotics sulfamethoxazole (46%) and sulfapyridine, which was not removed. Despite the low biomass productivity of the PBR, parameters such as the size of the reactors, the specific mixed cultures developed and the high temperatures and pH in the closed system may account for the overall good results, The efficiency and sustainability of these systems make them a solid, feasible treatment choice.This research is sponsored by FEDER funds through Portugal 2020 (PT2020), by the Competitiveness and Internationalization Operational Program (COMPETE 2020) and national funds through the Portuguese Foundation for Science and Technology, under the projects: UID/EMS/00285/2020, POCI-01-0145-FEDER-00763 and Friction 4.0 (POCI-01-0145-FEDER-032089). The author, D.G. Andrade is supported by the Portuguese Foundation for Science and Technology through SFRH/BD/130196/2017 fellowship. All supports are gratefully acknowledged.Peer ReviewedPostprint (author's final draft