Study of Flow in a Blanket Clarifier Using Computational Fluid Dynamics
Publication: Journal of Environmental Engineering
Volume 134, Issue 6
Abstract
This work simulated the flow pattern of the sludge blanket clarifier at the Bansin Water Treatment Plant, Taiwan by multiphase flow, three-dimensional analysis. The following three models were developed individually: One-phase flow (water) in the clarifier—this model acquires the basic water-flow pattern; a homogeneous porous medium at the bottom of the clarifier—this porous medium represents the sludge blanket; and, the Eulerian granular multiphase model, which was utilized to obtain solid effluent flux and to determine the effects of particle size and density on sludge blanket stability. Analytical results indicated that the clarifier has two principal circulations inside and outside the reaction well. A plentiful, dense and thick sludge blanket should exist at the clarifier bottom; otherwise particles could flow out through the gap between bottom of the reaction well and top of blanket surface, resulting in poor water quality. In the multiphase flow model, large particles and a high particle density are positively correlated with sludge blanket stability.
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Acknowledgments
The writers would like to thank the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract No. NSC NSCT94-2214-032-001. Ted Knoy is appreciated for his editorial assistance.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 134 • Issue 6 • June 2008
Pages: 443 - 455
Copyright
© 2008 ASCE.
History
Received: Jun 29, 2006
Accepted: Dec 10, 2007
Published online: Jun 1, 2008
Published in print: Jun 2008
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