Development of an Extended ASM3 Model for Predicting the Nitrous Oxide Emissions in a Full-Scale Wastewater Treatment Plant

Abstract

An Activated Sludge Model #3 (ASM3) based, pseudomechanistic model describing nitrous oxide (N ₂O) production was created in this study to provide more insight into the dynamics of N ₂O production, consumption, and emissions at a full-scale wastewater treatment plant (WWTP). N ₂O emissions at the studied WWTP are monitored throughout the plant with a Fourier transform infrared analyzer, while the developed model encountered N ₂O production in the biological reactors via both ammonia oxidizing bacteria (AOB) nitrification and heterotrophic denitrifiers. Additionally, the stripping of N ₂O was included by applying a K _L a-based approach that has not been widely used before. The objective was to extend the existing ASM3-based model of the plant and assess how well the full-scale emissions could be predicted with the selected model. The validity and applicability of the model were tested by comparing the simulation results with the comprehensive online data. The results show that the ASM3-based model can be successfully extended and applied to modeling N ₂O production and emissions at a full-scale WWTP. These results demonstrate that the biological reactor can explain most of the N ₂O emissions at the plant, but a significant proportion of the liquid-phase N ₂O is further transferred during the process.