Hydrodynamics of Secondary Settling Tanks and Increasing Their Performance Using Baffles
Publication: Journal of Environmental Engineering
Volume 136, Issue 1
Abstract
Generally, the flow in settling tanks is stratified, but the effect of buoyancy force on the flow field depends on the inlet concentration of particles and flow bulk velocity. A common approach for increasing settling tanks performance is to use baffles which can reduce effects of the unfavorable phenomena such as short circuiting between inlet and outlet and density currents in primary and secondary settling tanks, respectively. The suitable position of the baffles is related to the importance of buoyancy force. As a result, effects of inlet Reynolds and Froude numbers on the strength of buoyancy force are studied for a secondary settling tank and the results show that neither Reynolds nor Froude numbers are sufficient to be considered alone. Effect of buoyancy force on the suitable baffle position is also investigated. Results show that in high Reynolds numbers, the flow field and baffle position are not affected by the inlet Froude number.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 136 • Issue 1 • January 2010
Pages: 32 - 39
Copyright
© 2010 ASCE.
History
Received: Sep 1, 2008
Accepted: Jul 1, 2009
Published online: Jul 17, 2009
Published in print: Jan 2010
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