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Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands

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Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands. / Prado, Amanda; Ramírez-Vargas, Carlos A.; Arias, Carlos A.; Esteve-Núñez, Abraham.

In: Science of the total Environment, Vol. 735, 139522, 09.2020.

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Prado, Amanda ; Ramírez-Vargas, Carlos A. ; Arias, Carlos A. ; Esteve-Núñez, Abraham. / Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands. In: Science of the total Environment. 2020 ; Vol. 735.

Bibtex

@article{ad2111b2a2ed45c3badb3bcdda765386,
title = "Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands",
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 constructed wetlands, the METlands{\textregistered}, have been recently reported. METlands{\textregistered} replace gravel with 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 form inside the METland{\textregistered} 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{\textregistered} for removing pollutants, already much more efficient than standard gravel biofilters. COD removal was increased from 90% in METland{\textregistered} to 95% in the e-sink METland{\textregistered} as compared to 75% for the control, while total nitrogen removal was enhanced from 64% in METland{\textregistered} to 71% in e-sink METland{\textregistered} as compared to 55% for the control. Our results indicate that increasing the electrochemical availability of electron acceptors by using the e-sink will be a suitable method for controlling the electron flow inside the filter bed and can be integrated in full scale METlands{\textregistered} for achieving high removal rates.",
keywords = "Constructed wetland, Ec-biochar, Electroactive bacteria, METland{\textregistered}, Microbial electrochemical technologies",
author = "Amanda Prado and Ram{\'i}rez-Vargas, {Carlos A.} and Arias, {Carlos A.} and Abraham Esteve-N{\'u}{\~n}ez",
year = "2020",
month = sep,
doi = "10.1016/j.scitotenv.2020.139522",
language = "English",
volume = "735",
journal = "Science of the Total Environment",
issn = "0048-9697",
publisher = "Elsevier BV",

}

RIS

TY - JOUR

T1 - Novel bioelectrochemical strategies for domesticating the electron flow in constructed wetlands

AU - Prado, Amanda

AU - Ramírez-Vargas, Carlos A.

AU - Arias, Carlos A.

AU - Esteve-Núñez, Abraham

PY - 2020/9

Y1 - 2020/9

N2 - 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 constructed wetlands, the METlands®, have been recently reported. METlands® replace gravel with 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 form inside 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 METland® as compared to 55% for the control. Our results indicate that increasing the electrochemical availability of electron acceptors by using the e-sink will be a suitable method for controlling the electron flow inside the filter bed and can be integrated in full scale METlands® for achieving high removal rates.

AB - 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 constructed wetlands, the METlands®, have been recently reported. METlands® replace gravel with 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 form inside 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 METland® as compared to 55% for the control. Our results indicate that increasing the electrochemical availability of electron acceptors by using the e-sink will be a suitable method for controlling the electron flow inside the filter bed and can be integrated in full scale METlands® for achieving high removal rates.

KW - Constructed wetland

KW - Ec-biochar

KW - Electroactive bacteria

KW - METland®

KW - Microbial electrochemical technologies

UR - http://www.scopus.com/inward/record.url?scp=85085544278&partnerID=8YFLogxK

U2 - 10.1016/j.scitotenv.2020.139522

DO - 10.1016/j.scitotenv.2020.139522

M3 - Journal article

C2 - 32492567

AN - SCOPUS:85085544278

VL - 735

JO - Science of the Total Environment

JF - Science of the Total Environment

SN - 0048-9697

M1 - 139522

ER -