Effect of cathode material and its size on the abundance of nitrogen removal functional genes in microcosms of integrated bioelectrochemical-wetland systems

Sharvari S. Gadegaonkar, Timothé Philippon, Joanna M. Rogińska, Ülo Mander, Martin Maddison, Mathieu Etienne, Frédéric Barrière, Kuno Kasak, Rauno Lust, Mikk Espenberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Constructed wetland-microbial electrochemical snorkel (CW-MES) systems, which are short-circuited microbial fuel cells (MFC), have emerged as a novel tool for wastewater management, although the system mechanisms are insufficiently studied in process-based or environmental contexts. Based on quantitative polymerase chain reaction assays, we assessed the prevalence of different nitrogen removal processes for treating nitrate-rich waters with varying cathode materials (stainless steel, graphite felt, and copper) and sizes in the CW-MES systems and correlated them to the changes of N2O emissions. The nitrate and nitrite removal efficiencies were in range of 40% to 75% and over 98%, respectively. In response to the electrochemical manipulation, the abundances of most of the nitrogen-transforming microbial groups decreased in general. Graphite felt cathodes supported nitrifiers, but nirK-type denitrifiers were inhibited. Anaerobic ammonium oxidation (ANAMMOX) bacteria were less abundant in the electrochemically manipulated treatments compared to the controls. ANAMMOX and denitrification are the main nitrogen reducers in CW-MES systems. The treatments with 1:1 graphite felt, copper, plastic, and stainless-steel cathodes showed higher N2O emissions. nirS-and nosZI-type denitrifiers are mainly responsible for producing and reducing N2O emissions, respectively. Hence, electrochemical manipulation supported dissimilatory nitrate reduction to ammonium (DNRA) microbes may play a crucial role in producing N2O in CW-MES systems.

Original languageEnglish
Article number47
Number of pages15
JournalSoil Systems
Volume4
Issue number3
Early online date3 Aug 2020
DOIs
Publication statusPublished - Sep 2020

Keywords

  • ANAMMOX
  • Bioelectrochemical system
  • Cathode material and size
  • Constructed wetland
  • Denitrification
  • DNRA
  • Microbial electrochemical snorkel
  • Microbial fuel cell
  • Nitrification
  • Nitrous oxide

Fingerprint

Dive into the research topics of 'Effect of cathode material and its size on the abundance of nitrogen removal functional genes in microcosms of integrated bioelectrochemical-wetland systems'. Together they form a unique fingerprint.

Cite this