Work

Development of an analytical model for contaminant emission rates from passive cavities: CFD-based assessment and application to wastewater facilities

Year: 2025

Type: article

Abstract: Odor emissions from wastewater treatment plants (WWTPs) represent a growing environmental concern, particularly in densely populated urban areas. Passive sources such as open basins and tanks are characterized by complex flow structures that strongly influence contaminant emission dynamics. In this study, two-dimensional computational fluid dynamics (CFD) simulations were performed to investigate contaminant release from cavity-like passive sources, representing different cavity regimes classified according to the aspect ratio D/L. Over 1000 CFD simulations were conducted using a RANS k-ω SST turbulence model, systematically varying wind conditions and cavity geometries. The emission rate (ER) was evaluated across all configurations, enabling the identification of three distinct flow regimes (closed, open, and deep) with characteristic dispersion behaviors. Based on the CFD results, an analytical correlation for ER was developed for the closed and open regimes (D/L<1.5), directly linking ER to the Reynolds number and cavity geometry. For deep cavities (D/L>1.5), where stratification and vortex interactions dominate, more advanced modeling approaches remain necessary. The developed ER model provides a practical tool for estimating gas emissions from passive sources in WWTPs, which, when coupled with atmospheric dispersion models, facilitates comprehensive odor impact assessments under diverse operational and meteorological conditions

Source: Results in Engineering

DOI: 10.1016/j.rineng.2025.107705