Performance Assessment of Hydraulic Efficiency Indexes
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Volume 134, Issue 10
Abstract
The analysis of residence time distribution functions originating from tracer studies is one of the main tools for the assessment of hydraulic performance in water and wastewater treatment units. In order to simplify the analysis, hydraulic indexes extracted from these functions are normally used. In general, these indexes are divided into two categories: short circuit and mixing indicators. However, some indexes may be related to more than one physical phenomenon (i.e., short circuit, mixing, recirculation, dead zones), leading to erroneous interpretation. In this work their capability to evaluate short-circuit and mixing levels in water and wastewater treatment units is assessed. Among the indexes analyzed, , which is the time necessary for 10% of the tracer to leave the unit, is recommended as a short-circuit indicator and the dispersion index and the Morril index as mixing indicators, depending on the mixing level.
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Acknowledgments
The writers acknowledge Valdério Reisen for his invaluable support during the development of this work. The writers would like also to acknowledge William Bonino Rauen for his comments on the first version of this manuscript and CNPq, an agency of the Brazilian Government for the development of science and technology, for the scholarship given to the second writer to undertake his postgraduate studies.
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Information & Authors
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Published In
Journal of Environmental Engineering
Volume 134 • Issue 10 • October 2008
Pages: 851 - 859
Copyright
© 2008 ASCE.
History
Received: Mar 1, 2005
Accepted: Jan 30, 2007
Published online: Oct 1, 2008
Published in print: Oct 2008
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