Predicting Nitrous Oxide Emissions From the Activated Sludge Process Using BioWin and SUMO Mechanistic Models

ABSTRACT Reducing nitrous oxide (N 2 O) emissions from wastewater treatment is crucial for the water industry's net zero commitments. This research aimed to evaluate the capabilities of SUMO (Version 22.1.0) and BioWin (Version 6.2) in predicting N 2 O emissions and identifying mitigation opportunities. Using the Rosedale Wastewater Treatment Plant in Auckland, New Zealand, as a reference, both models were calibrated with field data and N 2 O measurements. Although both models predicted emissions well, BioWin required modifications. A larger dataset is recommended for better calibration. The SUMO model was used to test an ammonia‐based aeration control (ABAC) strategy, which involved a feedback control loop, narrow dissolved oxygen (DO) range with a minimum concentration of 1.5 mg/L and on/off aeration to minimize the aerated volume. This approach reduced emissions by 45% compared to the baseline. Full‐scale confirmation of these simulation results is necessary to validate the effectiveness of the proposed mitigation strategies.