Factors Affecting Nitrous Oxide Emissions from Activated Sludge Wastewater Treatment Plants—A Review

Liana Kemmou and Elisavet Amanatidou ()
Additional contact information
Liana Kemmou: Laboratory of Environmental Chemistry & Water and Wastewater Treatment, Department of Chemical Engineering, University of Western Macedonia, 50100 Kozani, Greece
Elisavet Amanatidou: Laboratory of Environmental Chemistry & Water and Wastewater Treatment, Department of Chemical Engineering, University of Western Macedonia, 50100 Kozani, Greece

Resources, 2023, vol. 12, issue 10, 1-26

Abstract: Nitrous oxide (N 2 O) is a greenhouse gas contributing to ozone layer depletion and climate change. Wastewater treatment plants (WWTPs) contribute significantly to the global anthropogenic N 2 O emissions. The main factors affecting N 2 O emissions are the dissolved oxygen concentration (DO), the nitrite accumulation, the rapidly changing process conditions, the substrate composition and COD/N ratio, the pH, and the temperature. Low DO in the nitrification process results in higher N 2 O emissions, whereas high aeration rate in the nitration/anammox process results in higher N 2 O production. High DO in the denitrification inhibits the N 2 O reductase synthesis/activity, leading to N 2 O accumulation. High nitrite accumulation in both the nitrification and denitrification processes leads to high N 2 O emissions. Transient DO changes and rapid shifts in pH result in high N 2 O production. Ammonia shock loads leads to incomplete nitrification, resulting in NO 2 − accumulation and N 2 O formation. Limiting the biodegradable substrate hinders complete denitrification, leading to high N 2 O production. A COD/N ratio above 4 results in 20–30% of the nitrogen load being N 2 O emissions. Maximum N 2 O production at low pH (pH = 6) was observed during nitrification/denitrification and at high pH (pH = 8) during partial nitrification. High temperature enhances the denitrification kinetics but produces more Ν 2 O emissions.

Keywords: N 2 O production pathways; hydroxylamine oxidation; nitrifier denitrification; heterotrophic denitrification; influence of DO; COD/N; pH and temperature; N 2 O sampling; N 2 O measurements (search for similar items in EconPapers)
JEL-codes: Q1 Q2 Q3 Q4 Q5 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/2079-9276/12/10/114/pdf (application/pdf)
https://www.mdpi.com/2079-9276/12/10/114/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jresou:v:12:y:2023:i:10:p:114-:d:1247319

Access Statistics for this article

Resources is currently edited by Ms. Donchian Ma

More articles in Resources from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().