Evaluation of Ozone Disinfection Systems: Characteristic Time T
Publication: Journal of Environmental Engineering
Volume 118, Issue 2
Abstract
The U.S. Environmental Protection Agency has recently promulgated drinking‐water regulations, known as the surface water treatment rule (SWTR), to control viruses, Giardia cysts, Legionella, and heterotrophic bacteria. The SWTR specifies overall minimum removal/inactivation efficiencies by filtration and disinfection for Giardia lamblia and viruses and uses the CT concept to predict in‐activation efficiencies. CT stands for the product of characteristic exposure time (T) and the characteristic concentration (C) in the disinfection chamber. This paper evaluates possible methods to determine the characteristic exposure time for ozone disinfection. The extent to which different measures of T (such as the hydraulic retention time, and ) actually ensure compliance with the required level of inactivation is evaluated by using segregated flow analysis and classical residence time distribution models. The analysis indicates that the minimum exposure time of 90% of the water in the disinfection unit, is a good measure to estimate disinfection performance in most cases. does not guarantee compliance with the SWTR in most cases.
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References
1.
Chick, H. (1908). “An investigation of the laws of disinfection.” J. Hygiene, 8(1), 92–158.
2.
Guidance manual for compliance with the surface water treatment requirements for public water systems. (1991). U.S. Envir. Protection Agency, Washington, D.C.
3.
Haas, C. N. (1989). “Inherent experimental variability.” Proc., Annual AWAA Conf., American Water Works Assoc., Denver, Colo., 67.
4.
Hoff, J. C. (1989). “Strengths and weaknesses of using CT values to evaluate disinfection practice.” Proc., Annual AWWA Conf., American Water Works Assoc., Denver, Colo., 9.
5.
Joost, R. D., Jackson, L. A., and Bollyky, L. J. (1989). “Optimization of ozone contactors for drinking water disinfection.” Proc. of the 9th Ozone World Congress, L. J. Bollyky, ed., International Ozone Assoc., Zurich, Switzerland. Vol. 1, 551.
6.
Lev, O., and Regli, S. (1992). “Prediction of inactivation level in ozone disinfection systems: Selection of characteristic concentration.” J. Envir. Engrg., ASCE (in press).
7.
Levenspiel, O. (1972). Chemical reaction engineering. Second Ed., John Wiley & Sons, New York, N.Y.
8.
Mujumdar, S. B., Ceckler, W. H., and Sproul, O. J. (1973). “Inactivation of poliovirus in water by ozonation.” J. WPCF, 45(12), 2433–2443.
9.
“National primary drinking water regulations: Filtration, disinfection, turbidity, Giardia lamblia, viruses, Legionella, and heterotrophic bacteria.” Fed. Reg. 54:124:27486, U.S. Envir. Protection Agency, Washington, D.C.
10.
Nauman, E. B., and Buffham, B. A. (1983). Mixing in continuous flow systems. John Wiley & Sons, New York, N.Y.
11.
Regli, S. (1989). “USEPA disinfection regulations.” Proc., Annual AWWA Conf., American Water Works Assoc., Denver, Colo., 1.
12.
Seinfeld, J. H., and Lapidus, L. (1984). “Mathematical methods in chemical engineering. Process modeling estimation and identification, Vol. 3, Prentice Hall Inc., Englewood Cliffs, N.J.
13.
Severin, B. F., and Churn, C. C. (1989). “Kinetics of microbial inactivation.” Proc., Annual AWWA Conf., American Water Works Assoc., Denver, Colo., 21.
14.
Sobsey, M. D. (1989). “Inactivation of health related microorganisms in water by disinfection processes.” Water Sci. Tech. 21(3), 179–195.
15.
Stolarik, G. L., and Christie, J. D. (1987). “Projection of ozone C‐T values, Los Angeles Aqueduct Filtration Plant.” Int. Ozone Assoc. Conf., International Ozone Assoc., Zurich, Switzerland. Monroe, Mich., April.
16.
Trussell, R. R., and Chao, J. L. (1977). “Rational design of chlorine contact facilities.” J. WPCF, 49(2), 659–667.
17.
Watson, H. E. (1908). “A note on the variation of the rate of disinfection with change in the concentration of the disinfectant.” J. Hygiene, 8(2), 536–538.
18.
Wickramanayake, G. B., Rubin, A. J., and Sproul, O. J. (1984). “Inactivation of Naegleria and Giardia cysts in water by ozonation.” J. WPCF, 56(8), 983–988.
19.
Wolfe, R. L., Stewart, M. H., Scott, K. N., and McGuire, M. J. (1989). “Inactivation of Giardia Muris and indicator organisms seeded in surface water supplies by peroxone and ozone.” Envir. Sci. Tech., 23(6), 744–745.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 118 • Issue 2 • March 1992
Pages: 268 - 285
Copyright
Copyright © 1992 ASCE.
History
Published online: Mar 1, 1992
Published in print: Mar 1992
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