A1 Journal article (refereed)
Nitrate removal microbiology in woodchip bioreactors : a case-study with full-scale bioreactors treating aquaculture effluents (2020)
Aalto, S. L., Suurnäkki, S., von Ahnen, M., Siljanen, H. M. P., Pedersen, P. B., & Tiirola, M. (2020). Nitrate removal microbiology in woodchip bioreactors : a case-study with full-scale bioreactors treating aquaculture effluents. Science of the Total Environment, 723, Article 138093. https://doi.org/10.1016/j.scitotenv.2020.138093
JYU authors or editors
Publication details
All authors or editors: Aalto, Sanni L.; Suurnäkki, Suvi; von Ahnen, Mathis; Siljanen, Henri M. P.; Pedersen, Per Bovbjerg; Tiirola, Marja
Journal or series: Science of the Total Environment
ISSN: 0048-9697
eISSN: 1879-1026
Publication year: 2020
Volume: 723
Article number: 138093
Publisher: Elsevier
Publication country: Netherlands
Publication language: English
DOI: https://doi.org/10.1016/j.scitotenv.2020.138093
Publication open access: Not open
Publication channel open access:
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/68374
Abstract
Woodchip bioreactors are viable low-cost nitrate (NO3−) removal applications for treating agricultural and aquaculture discharges. The active microbial biofilms growing on woodchips are conducting nitrogen (N) removal, reducing NO3− while oxidizing the carbon (C) from woodchips. However, bioreactor age, and changes in the operating conditions or in the microbial community might affect the NO3− removal as well as potentially promote nitrous oxide (N2O) production through either incomplete denitrification or dissimilatory NO3− reduction to ammonium (DNRA). Here, we combined stable isotope approach, amplicon sequencing, and captured metagenomics for studying the potential NO3− removal rates, and the abundance and community composition of microbes involved in N transformation processes in the three different full-scale woodchip bioreactors treating recirculating aquaculture system (RAS) effluents. We confirmed denitrification producing di‑nitrogen gas (N2) to be the primary NO3− removal pathway, but found that 6% of NO3− could be released as N2O under high NO3− concentrations and low amounts of bioavailable C, whereas DNRA rates tend to increase with the C amount. The abundance of denitrifiers was equally high between the studied bioreactors, yet the potential NO3− removal rates were linked to the denitrifying community diversity. The same core proteobacterial groups were driving the denitrification, while Bacteroidetes dominated the DNRA carrying microbes in all the three bioreactors studied. Altogether, our results suggest that woodchip bioreactors have a high genetic potential for NO3− removal through a highly abundant and diverse denitrifying community, but that the rates and dynamics between the NO3− removal pathways depend on the other factors (e.g., bioreactor design, operating conditions, and the amount of bioavailable C in relation to the incoming NO3− concentrations).
Keywords: denitrification; nitrous oxide; nitrogen; bioreactors; aquaculture
Free keywords: denitrification; DNRA; nitrogen removal; nitrous oxide; recirculation aquaculture systems
Contributing organizations
Related projects
- Micro-RIP Functional analysis of uncultivated microbes using radioisotope probing
- Tiirola, Marja
- European Commission
Ministry reporting: Yes
Reporting Year: 2020
JUFO rating: 2