Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands

Prado, A. and Ramírez-Vargas, C.A. and Arias , C.A. and Esteve-Núñez, A. (2020) Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands. Science of The Total Environment, 735. p. 139522. ISSN 00489697

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Official URL: https://doi.org/10.1016/j.scitotenv.2020.139522

Abstract

Constructed wetlands are an effective biofilter-based technology for treating wastewater in a sustainable way; however, their main disadvantage is a large area footprint. To cope with this limitation a new generation of constructedwetlands, theMETlands®, have been recently reported.METlands® replace gravelwith a granular electrically conductive material to enhance the oxidative metabolisms of electroactive bacteria by facilitating the flux of electron through the material and, consequently, increase bioremediation rates. In this work we evaluated the performance of a new electron sink (e-sink) device with the purpose of controlling and enhancing the electrochemical consumption of electrons from microbial metabolism without energy consumption. The e-sink device was integrated inside the biofilter bed and was tested using different electron acceptors with high redox potentials, like oxygen and hypochlorite. Interestingly, the presence of the e-sink allowed novel redox gradients to forminside the METland® and, consequently, a new electron flow was demonstrated by measuring both the electric potential and current density profiles of the bed. Three independent biofilters were constructed and operated under flooded conditions. Ec-coke and electroconductive biochar (ec-biochar) were used as electrically conductive bed materials, while gravel was used as an inert control. Furthermore, e-sink integration inside the electrically conductive bed outperformed METlands® for removing pollutants, already much more efficient than standard gravel biofilters. COD removal was increased from 90% in METland® to 95% in the e-sink METland® as compared to 75% for the control, while total nitrogen removal was enhanced from 64% in METland® to 71% in e-sink

Item Type: Article
Uncontrolled Keywords: Constructed wetland; METland®; Microbial electrochemical technologies; Electroactive bacteria; Ec-biochar
Subjects: Q Science > QD Chemistry
T Technology > TD Environmental technology. Sanitary engineering
Depositing User: Belén Barroeta
Date Deposited: 02 Nov 2021 16:43
Last Modified: 03 Nov 2021 11:01
URI: http://eprints.imdea-agua.org:13000/id/eprint/1172

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