Fluidization in an Anaerobic EGSB Reactor: Analysis of Primary Wakes and Modeling of Sludge Blanket
Publication: Journal of Environmental Engineering
Volume 135, Issue 8
Abstract
Fluidization of biogranules in an anaerobic expanded granular sludge bed (EGSB) reactor is stochastic in nature and it is a function of the size distribution and the frequency of generation of flow-through gas bubbles in the reactor. Other factors that contribute to the distribution of granules along the height of the reactor are the settling characteristics of granules and the fluid velocity. A simulation was conducted in a test column to obtain a relationship between the flow-through gas and granules at different heights along the column. This relationship was combined with the pattern of gas flow through an identical EGSB reactor to create a model to predict the concentration of granules at different heights along the reactor. The model can predict well the stochastic nature of the axial distribution of granules but underestimates the number of granules at different heights. The reasons for such deviations are explained. The pattern of granule shedding from the primary wake associated with spherical cap bubbles and terminal velocities of bubbles have also been studied and modeled to estimate the maximum height of ascent of granules under isolated spherical cap bubbles. The results of this model agreed well with the experimental observations.
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Acknowledgments
The study was supported by the Natural Sciences and Engineering Research Council of Canada—Discovery Grant of the third writer. The writers would like to express their gratitude to Dr. Katy A. Haralampides, Dr. Dennis Connor, and Mr. Andres Rodriguez of the University of New Brunswick for their technical support.NSERC
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 135 • Issue 8 • August 2009
Pages: 700 - 707
Copyright
© 2009 ASCE.
History
Received: Jun 22, 2007
Accepted: Jun 12, 2008
Published online: Jul 15, 2009
Published in print: Aug 2009
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