Alternative Index for Interpretation of RTD Curves
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VIEW THE REPLYPublication: Journal of Environmental Engineering
Volume 125, Issue 3
Abstract
An alternative approach for the interpretation of the residence time distribution (RTD) curves is proposed. The method has semiempirical basis, supported upon a gross fit of the tracer curve area by two triangles in order to obtain a single parameter (φ index) that indicates whether the system tends to a completely mixed or to a plug flow hydraulic behavior. In order to verify its applicability, 28 experiments were carried out in a laboratory tank (138 L). In these experiments, the influence of aeration, packing, and number of baffles on the tank hydraulic behavior was assessed using the index as well as conventional models. The general results obtained in the laboratory tank experiments showed that mixed tanks tend to have a larger dead volume fraction (DVF) than plug-flow tanks and that packed tanks tend to have a smaller DVF than nonpacked tanks. This index provides a reliable, quick, and simple method for the interpretation of the RTD curves when hydraulic behavior trends or tank modifications for hydraulic improvements are evaluated.
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References
1.
Camp, T. R. ( 1946). “Sedimentation and the design of settling tanks.” ASCE, Paper 2285, 895–958.
2.
Cholette, A., and Cloutier, I. ( 1959). “Mixing efficiency determinations for continuous flow systems.” Can. J. Chem. Engrg., June, 105–112.
3.
Hahn, H. H. ( 1990). “Sedimentation and flotation: Present status and necessary development: An introduction.” Water Supply, 8, 111–122.
4.
Hall, E. R. ( 1985). “Nonintrusive estimation of active volume in anaerobic reactors.” Water Pol. Res. J. Canada, 20(2), 44–54.
5.
Hamoda, M. F., and Abd-El-Bary, F. ( 1987). “Operating characteristics of the aerated submerged fixed-film (ASFF) bioreactor.” Wat. Res., 21(8), 939–947.
6.
Jiménez, B., Noyola, A., and Capdeville, B. ( 1988). “Selected dyes for residence time distribution in bioreactors.” Biotechnol. Tech., 2(2), 77–82.
7.
Levenspiel, O. ( 1963). “Patterns of flow in chemical process vessels.” Adv. in Chem. Engrg., Vol. 4, Academic, San Diego.
8.
Levenspiel, O. ( 1972). Chemical Reaction Engineering . 2nd Ed., Wiley, New York.
9.
Levenspiel, O., and Smith, W. K. ( 1957). “Notes on the diffusion-type model for the longitudinal mixing of liquids in flow.” Chem. Engrg., Sci., 6, 227–233.
10.
Monteith, H. D., and Stephenson, J. P. ( 1981). “Mixing efficiencies in full-scale anaerobic digesters by tracers methods.” J. Water Pol. Cont. Fed., 53(1), 78–84.
11.
Morrill, A. B. ( 1932). “Sedimentation basin research and design.” J. Am. Water Works Assoc., 24, 1442.
12.
Samson, R., Van der Berg, I., and Kennedy, K. J. ( 1984). “Influence continuous versus channels on mixing characteristics and performance of anaerobic downflow stationary fixed film (DSFF) reactors before and during waste treatment.” Proc., 39th Ind. Waste Conf., Purdue University, West Lafayette, Ind., 677–685.
13.
Tekippe, R. J., and Cleasby, J. L. (1968). “Model studies of the peripheral feed settling tank.”Proc., J. Sanitary Engrg. Div., ASCE, 85, 085–102.
14.
Villemonte, J. R., Rohlich, G. A., and Wallace, A. T. ( 1966). “Evaluation of oil water separator inlet devices.” Proc., 31st Midyear Meeting of the American Petroleum Institute, Div. of Refining. Houston, Texas, 303–310.
15.
Young, H. W., and Young, J. C. (1988). “Hydraulic characteristics of upflow anaerobic filters.”J. Envir. Engrg., ASCE, 114(3), 621–638.
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Published online: Mar 1, 1999
Published in print: Mar 1999
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