Modeling Separation of Flocculant Particles in Horizontal-Flow Gravel Bed
Publication: Journal of Environmental Engineering
Volume 123, Issue 12
Abstract
Vertical- or horizontal-flow gravel beds can be used in water treatment as roughing filters. To improve its performance, the horizontal-flow roughing filtration (HRF) process was modified in an earlier study by applying a constant dose of 1 mg Al(III)/l coagulant (“direct” horizontal-flow roughing filtration). After rapid mixing, the destabilized suspension is passed on to the horizontal-flow gravel bed, which is divided into two or three compartments. The first compartment, here referred to as the gravel bed, contains the largest grain size (15–25 mm diameter) and acts as a combined flocculator and settler. A mathematical model for the gravel bed was developed based on an analogy with a parallel plate settler in which both the sedimentation and flocculation processes are incorporated. An experimental methodology was derived for applying the model to different suspension types using column settling tests. The model was validated experimentally. The procedure developed here would allow the optimization of design and operation of the gravel bed for different raw water characteristics and for different process conditions.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 123 • Issue 12 • December 1997
Pages: 1254 - 1260
Copyright
Copyright © 1997 American Society of Civil Engineers.
History
Published online: Dec 1, 1997
Published in print: Dec 1997
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