Mechanisms of Ballasted Floc Formation
Publication: Journal of Environmental Engineering
Volume 133, Issue 3
Abstract
Ballasted flocculation processes were studied at laboratory scale to evaluate the mode of transport of ballasting agent from bulk liquid into the chemical floc and establish a new model for assessing the mechanisms of ballasted floc formation. For this purpose, a test program consisting of bench scale observations, microscopic observations, density tests, and centrifugal settling tests was developed. Ballasted flocs were found to be formed by a mechanism in which the ballasting agent is incorporated into the floc matrix by inertial forces, and the ballasting agent taking the place of the bound water content . Bulk density of ballasted flocs was found to be linearly related to the ballasting agent dose . This study provided a better understanding of the mechanisms controlling the interaction between ballasting agent and coagulant/polymer chemical floc.
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Acknowledgments
The research described in this paper was supported in part by Challenge Environmental Laboratories Inc. of Fayetteville, Ark., and in part by the Civil Engineering Department of the University of Arkansas at Fayetteville. The writers want to thank Mark Kuss, Frances Griffith, and Art Brown for their technical support.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 133 • Issue 3 • March 2007
Pages: 271 - 277
Copyright
© 2007 ASCE.
History
Received: Sep 17, 2004
Accepted: Aug 9, 2006
Published online: Mar 1, 2007
Published in print: Mar 2007
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