CFD Investigation of the effects of bubble aerator layouts on hydrodynamics of an activated sludge channel reactor.
Environ Technol
; 40(20): 2657-2670, 2019 Aug.
Article
em En
| MEDLINE
| ID: mdl-29495946
ABSTRACT
In this paper, computational fluid dynamics (CFD) simulations are employed to characterize the effects of bubble aerator layouts (i.e. spatial arrangement) on the hydrodynamics in activated sludge (AS) reactors. The first configuration considered is a channel reactor with aerators placed alongside one lateral wall, for which velocity measurements are available in literature. CFD results were in good agreement with experimental data, which proves that the model is sufficiently accurate and predictive. Accordingly, simulations and numerical residence time distribution tests were conducted for different aerator layouts to determine their effects on the reactor hydrodynamics. The results revealed that the flow characteristics are extremely sensitive to the aerators arrangement given the high gas flow rates used in AS processes. Among the layouts investigated, the one where diffusers are placed all over the reactor floor has led to the least dispersive flow, i.e. which characteristics best tend toward that of an ideal plug flow reactor. Indeed, this flow field presented the lowest average turbulent diffusion and the most uniform axial velocity and turbulence fields. Such a flow behaviour is expected to be highly beneficial for biological treatment since it reduces pollutant dilution by axial diffusion and limits raw wastewater channelling to the outlet.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Esgotos
/
Hidrodinâmica
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Environ Technol
Assunto da revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
França