CFD prediction of odorous compound dispersion: Case study examining a full scale waste water treatment plant

Waste water treatment plants (WWTPs) are potential sources of offensive odours that can lead to nuisance within nearby communities. A computational fluid dynamics (CFD) model was used to examine the behaviour of contaminants concentration plume released to the atmosphere, and to quantify the potential odour strength causing impact on the neighbourhood, by the WWTP of the city of Monastir, Tunisia. The CFD model developed was validated using the National Environmental Protection Agency, Tunisia ambient air quality measurements taken at outskirts of the studied WWTP. Sludge drying beds were considered here to be the major source of odorous compounds. The model was used to examine issues that influence atmospheric dispersion of pollutants released by the drying beds. Aspects such as aerodynamics and site topography on odorous compounds dispersion in the vicinity of the station and around buildings were investigated. Odorous compounds dispersion was simulated using the FLUENT CFD software and the k–ɛ turbulent transport model. A non-uniform meshing was used in regions of high concentration gradients, particularly in the neighbourhood of the treatment plant and around buildings.