Insights from biokinetic modelling of nitrous oxide emissions from a full-scale wastewater treatment plant

“Nitrous oxide (N2O) is a potent and harmful greenhouse gas, having a global warming potential 298 times greater than that of carbon dioxide (CO2), on a 100-year time scale [1]. Therefore, its increasing atmospheric concentration is contributing severely to climate change [2]. Wastewater treatment plants (WWTPs) are now considered to be a significant source of N2O and hence there is a need to increase our understanding of this phenomenon and identify mitigation measures to reduce the emissions. N2O production in WWTPs occurs during biological nitrogen removal (BNR), with two production pathways are associated with autotrophic nitrification, referred to as hydroxylamine oxidation and nitrifier denitrification pathways, and one due to incomplete heterotrophic denitrification [3, 4, 5]. Long duration measurement campaigns of N2O have further reported distinctive and seasonal variations [6, 7]. Particularly, seasonal emission peaks have been recorded during the spring months where a high load of N2O is released, and lower emissions are reported during autumn [8]. Biokinetic or mechanistic modelling is one method that can be used to better understand the N2O seasonal dynamics from WWTPs and in devising control strategies to mitigate it. Over the years, biokinetic models that included the N2O production dynamics have been investigated [9, 10, 11]. However, a majority of the studies were carried out on datasets obtained from controlled environments or the duration of data used for calibration purposes can be considered short to medium-term.
In this study, a biokinetic model was setup for a real-life full scale WWTP and was calibrated using one year of observed data to account for the seasonal variations of N2O emissions. Specifically, the modelling focuses on predicting the N2O seasonal emission peak and gaining insights on the underlying biokinetic processes and kinetic parameters potentially responsible for it.”

(Citaat: Seshan, S., Poinapen, J., et.al. – Insights from biokinetic modelling of nitrous oxide emissions from a full-scale wastewater treatment plant – 19th International Computing & Control for the Water Industry Conference, 4-7 September 2023)