Constructed wetland microcosms for the removal of organic micropollutants from freshwater aquaculture effluents

The presence of organic micropollutants (MPs) in the aquatic environment is strongly related to their difficult elimination by conventional water and wastewater treatment processes. Therefore, alternative treatment technologies are required to overcome this problem. In this domain, constructed wetlands (CWs) have gained increasing attention in the last years, mainly due to the low-cost, simple operation/maintenance and environmental friendliness of these systems. However, studies on the application of CWs to remove MPs from freshwater aquaculture effluents are still scarce. In this work, planted (Phragmites australis) vertical subsurface flow CWs, at microcosm scale, were investigated for the removal of MPs found in non-spiked freshwater aquaculture effluents, namely atrazine, isoproturon, perfluorooctanesulfonic acid (PFOS), clarithromycin, erythromycin, fluoxetine, norfluoxetine, and 2-ethylhexyl-4-methoxycinnamate (EHMC). A wider multi-component set of 36 MPs was also studied by adding these MPs at 100 ng L −1 to the same matrix (alachlor, atrazine, chlorfenvinphos, isoproturon, PFOS, azithromycin, clarithromycin, erythromycin, diclofenac, methiocarb, acetamiprid, clothianidin, thiacloprid, thiamethoxam, EHMC, simazine, atorvastatin, bezafibrate, carbamazepine, cephalexin, ceftiofur, citalopram, clindamycin, clofibric acid, diphenhydramine, enrofloxacin, fluoxetine, ketoprofen, metoprolol, norfluoxetine, ofloxacin, propranolol, tramadol, trimethoprim, venlafaxine, and warfarin). High weekly removal efficiencies (>87%) were observed for all MPs in both non-spiked and spiked experiments, with the exception of EHMC (removal rates between 0 and 86%). These results emphasize the potential of CWs to remove MPs from freshwater aquaculture effluents, but also the need to enhance the performance of these systems for the elimination of some recalcitrant MPs, such as EHMC, which was found at high concentrations in the studied effluents. © 2018 Elsevier

This work was financially supported by Project POCI-01-0145-FEDER-006984 – Associate Laboratory LSRE-LCM funded by ERDF (European Regional Development Fund) through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through Fundação para a Ciência e a Tecnologia (FCT). This research was also partially supported by CIIMAR (Interdisciplinary Centre of Marine and Environmental Research) Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT and ERDF, in the framework of the programme PT2020 and by the structured Program of R&D&I INNOVMAR - Innovation and Sustainability in the Management and Exploitation of Marine Resources, reference NORTE-01-0145-FEDER-000035, namely within the Research Line INSEAFOOD within the R&D Institution CIIMAR, supported by the Northern Regional Operational Programme (NORTE2020), through the ERDF. AMG and ARR acknowledge the research grant from FCT (Refs. SFRH/BD/133117/2017 and SFRH/BPD/101703/2014, respectively). The authors would like to acknowledge the financial support provided by COST- European Cooperation in Science and Technology , to the COST Action ES1403: New and emerging challenges and opportunities in wastewater reuse (NEREUS). Disclaimer: The content of this article is the authors' responsibility and neither COST nor any person acting on its behalf is responsible for the use, which might be made of the information contained in it. Appendix A