Numerical modelling of surface aeration and N2O emission in biological water resource recovery

Yuge Qiu; Sara Ekström; Borja Valverde-Pérez; Barth F Smets; Javier Climent; Carlos Domingo-Félez; Raúl Martínez Cuenca; Benedek G Plósz

doi:10.1016/j.watres.2024.121398

Numerical modelling of surface aeration and N₂O emission in biological water resource recovery

Water Res. 2024 May 15:255:121398. doi: 10.1016/j.watres.2024.121398. Epub 2024 Feb 29.

Authors

Yuge Qiu¹, Sara Ekström², Borja Valverde-Pérez², Barth F Smets², Javier Climent³, Carlos Domingo-Félez², Raúl Martínez Cuenca³, Benedek G Plósz⁴

Affiliations

¹ Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK. Electronic address: yq306@bath.ac.uk.
² Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, 2800 Kgs., Lyngby, Denmark.
³ Department of Mechanical Engineering and Construction, Universitat Jaume I, Av. Vicent Sos Baynat, s/n 12071 Castellón (Spain).
⁴ Department of Chemical Engineering, University of Bath, Claverton Down, Bath BA2 7AY, UK; SWING - Department of Built Environment, Oslo Metropolitan University, St Olavs plass 0130, Oslo, Norway.

PMID: 38503179
DOI: 10.1016/j.watres.2024.121398

Abstract

Biokinetic modelling of N₂O production and emission has been extensively studied in the past fifteen years. In contrast, the physical-chemical hydrodynamics of activated sludge reactor design and operation, and their impact on N₂O emission, is less well understood. This study addresses knowledge gaps related to the systematic identification and calibration of computational fluid dynamic (CFD) simulation models. Additionally, factors influencing reliable prediction of aeration and N₂O emission in surface aerated oxidation ditch-type reactor types are evaluated. The calibrated model accurately predicts liquid sensor measurements obtained in the Lynetten Water Resource Recovery Facility (WRRF), Denmark. Results highlight the equal importance of design and operational boundary conditions, alongside biokinetic parameters, in predicting N₂O emission. Insights into the limitations of calibrating gas mass-transfer processes in two-phase CFD models of surface aeration systems are evaluated.

Keywords: Biological water resource recovery; Calibration of single- and two-phase models; Computational fluid dynamics; Factor screening using design of experiment; Oxygen and N(2)O gas mass-transfer; Surface aeration.