Boosting pharmaceutical removal through aeration in constructed wetlands

Abstract

This work evaluated the removal efficiency of 13 wastewater-borne pharmaceuticals in a pilot constructed wetland (CW) operated under different aeration strategies (no aeration, intermittent and continuous). Aeration improved the removal of conventional wastewater parameters and the targeted micropollutants, compared to the non-aerated treatment. Reduction of chemical oxygen demand (COD) and total nitrogen (TN) was slightly higher applying intermittent aeration than applying continuous aeration, the opposite was observed for the investigated pharmaceuticals. Seven targeted compounds were found in influent wastewater, and five of them (acetaminophen, diclofenac, ketoprofen, bezafibrate and gemfibrozil) were efficiently removed (> 83%) in the aerated systems. The overall risk of the investigated samples against aquatic ecosystems was moderate, decreasing in the order influent > no aeration > intermittent aeration > continuous aeration, based on the hazard quotient approach. Lorazepam, diclofenac and ketoprofen were the pharmaceuticals that could contribute the most to this potential environmental impact of the CW effluents after discharge. To the authors' knowledge this is the first sound study on the removal and fate of ketoprofen, bezafibrate, and lorazepam in aerated CWs, and provides additional evidence on the removal and fate of acetaminophen, diclofenac, gemfibrozil, and carbamazepine in this type of bioremediation systems at pilot plant scale.

This research study has received funding from the European Union's Seventh Framework Programme managed by the REA – Research Executive Agency http://ec.europa.eu/research/rea (FP7/2007_2013) under project reference 606326. Adrián López Rivera is acknowledged for assistance in sample collection and SPE. C. Ávila, M.J. García and E. Uggetti would like to thank the Spanish State Research Agency of the Spanish Ministry of Science, Innovation and Universities (AEI-MCIU) for their research fellowships FJCI-2014-22245, IJCI-2017-34601 and RYC2018-025514-I, respectively. Authors would also acknowledge the Government of Catalonia (Consolidated Research Group 2017 SGR 1029) for their financial support. SCIEX is acknowledged for providing the loan instrument LC/HRMS QTOF X500R.

Peer Reviewed

Postprint (author's final draft)