BioWin and SUMO models as digital tools to predict and reduce nitrous oxide emissions from the activated sludge wastewater treatment: PAPER & PRESENTATION
Dr. Ralitza Nikolova-Kuscu & Laura Fonseca-Aponte, Mott MacDonald, UK
(free)
Abstract
Reducing N2O emissions from wastewater treatment is important to achieve the water industry’s net zero commitments. Mechanistic modelling is one of the tools available to quantify and mitigate these emissions. The objective of this research was to understand the capabilities of SUMO and BioWin to predict nitrous oxide (N2O) emissions, what model modifications are required and identify site-specific
opportunities for N2O mitigation. The Rosedale Wastewater Treatment Plant, Auckland, New Zealand was used as a reference site. The BioWin and SUMO models were calibrated using field-data and N2O liquid and gas-phase measurements. Both models predicted N2O emissions relatively well, although BioWin required modifications. A larger data set is recommended to improve model calibration.
The model developed in SUMO was used to implement and test an ammonia-based aeration control (ABAC) based on a feedforward control to avoid nitrification beyond what is necessary for discharge permit requirement. The ABAC strategy investigated different DO control ranges and recommended a narrow DO range with minimum DO concentration of 1 mg/l, coupled with on/off aeration to minimise the aerated volume. This resulted in a 45% reduction in emissions compared to the baseline scenario. The simulation results from the mitigation scenarios should be confirmed at full scale.
