Thorough Dispersal of Dosants in Conduits
Publication: Journal of Hydraulic Engineering
Volume 141, Issue 5
Abstract
Liquid streams of chemicals (dosants) such as sodium hypochlorite frequently need to be quickly and thoroughly mixed across a water or wastewater flow. Where no mixing tanks, stirrers, or pumps are available to ensure rapid and complete mixing, the existing flow turbulence in the conduit will be adequate for mixing if the effective available conduit length exceeds a value proportional to , where is the conduit’s hydraulic radius, is the number of well-spaced dosing points at the dosing station, and is the Darcy-Weisbach factor for the conduit. The proportionality varies slightly with the degree of uniformity required of the dosant concentration across the conduit cross section. The analysis, based on consideration of a square conduit, agrees closely with one (by others) based on a conduit of circular cross section. Laboratory and field data support the analysis to a useful extent.
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Acknowledgments
The author acknowledges CDM Smith’s corporate support for this work, and the helpful reviews and suggestions by his CDM Smith colleagues Charles Allaben, Mark Allen, Carl Frizzell, Andrew Reid, and Christopher Schultz.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 141 • Issue 5 • May 2015
Copyright
© 2015 American Society of Civil Engineers.
History
Received: May 26, 2014
Accepted: Dec 3, 2014
Published online: Jan 20, 2015
Published in print: May 1, 2015
Discussion open until: Jun 20, 2015
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