Evaluation of mixing conditions and its influence over free residual

Main Article Content

C Montoya
C H Cruz
P Torres
Santiago Laín
J C Escobar

Keywords

water age, water quality, free residual chlorine, chlorine decay, thermal stratification, mixing regime, compensation tank, temperature, tracer.

Abstract

We performed a real scale evaluation of mixing conditions and its influence on water quality in a compensation tank of drinking-water distribution system located in the city of Cali, Colombia. The hydrodynamic study with continuous injection of tracer, and temperature and free chlorine measurements for identifying the mixing regime in the tank’s interior, residence time, thermal stratification, and chlorine variations in the stored water showed the typical characteristics of a compensation tank. We concluded that water recirculation, inadequate water exchange, low moment fluxes associated with low velocity flows, and punctual thermal stratification could lead to high water age, high residence times in the tank, inadequate mixing, and important loss of free residual chlorine. The methodology developed is suitable for evaluation and optimization of compensation tanks of drinking water distribution systems.

PACS: 92.40.-t, 92.40.qc

MSC: 62J10

Downloads

Download data is not yet available.
Abstract 840 | PDF (Español) Downloads 306

References

[1] F. Mahmood, J. Pimblett, N. Grace, W. Grayman. Evaluation of water mixing characteristics in distribution system storage tanks, Journal AWWA, ISSN 2164-4535, 97(3), 74-88 (2005).

[2] K. Lansey, P. Boulos. Comprehensive handbook on water quality analysis for distributions systems,First edition, ISBN 0-9745689-3-7. Ed. MWH Soft, California, 2005.

[3] L. Rossman, W. Grayman. Scale-model studies of mixing in drinking water storage tanks, Journal of Environmental Engineering, ISSN 0733-9372, 125(8), 755-761 (1999).

[4] W. Grayman, L. Rossman, R. Deininger, C. Smith, A. Clifford, J. Smith. Mixing and aging of water in distribution system storage facilities, Journal AWWA, ISSN 2164-4535, 96(9), 70–80 (2004). Referenciado en 12

[5] O. Nordblom, L. Bergdahl. Initiation of stagnation in drinking water storage tanks, Journal of Hydraulic Engineering, ISSN 0733-9429, 130(1), 49–57 (2004).

[6] P. Boulos, W. Grayman, R. Bowcock, J. Clapp, L. Rossman, R. Clark, R. Deininger, A. Dhingra. Hydraulic mixing and free chlorine residual in reservoirs, Journal AWWA, ISSN 2164–4535, 88(7), 48–59 (1996).

[7] W. Grayman, L. Rossman, C. Arnold, R. Deininger, Ch. Smith, J. Smith, R. Schnipke. Water quality modeling for distribution system storage facilities, ISBN-13 978-1583210062. Ed. American Water Works Association, 1999.

[8] Colombia, Ministerio de la Protección Social. Ministerio de Ambiente, Vivienda y Desarrollo Territorial , Resolución 2115. Bogotá D.C, Colombia. 2007.

[9] Environmental Protection Agency EPA. The Effectiveness of Disinfectant Residuals in the Distribution System, diciembre de 2010.

[10] E. Edgington. Randomization Test, Third Edition, Revised and expanded, ISBN 9780824796693. Ed. Marcel Dekker Inc., New York, 1995.

[11] S. Jayanti. Hydrodynamics of jet mixing in vessel , Journal Chemical Engineering Science, ISSN 0009–2509, 56(1), 193–210 (2001).

[12] J. Rojas, A. Ruiz. Determinación y evaluación de las constantes de decaimiento de cloro libre y formación de trihalometanos en la red del sistema Nápoles - Ciudad Jardín, Tesis de Pregrado. Universidad del Valle. Colombia, 2008.

[13] P. Yu-Hung Chuo. An investigation of a modelling system for assessing the impact of stratification on mixing in drinking water service reservoirs, Tesis Doctoral. University of New South Wales, 2003.

[14] V. Gauthier, M. Besner, B. Barbeau, R. Millette, M. Prévost. Storage tank management to improve drinking water quality: case study, Journal of Water Resources Planning and Management, ISSN 0733–9496, 126(4), 221–228 (2000).

[15] J. Ecuru, J. Okot-Okumu, T. Okurut. Monitoring residual chlorine decay and coliform contamination in water distribution network of Kampala, Uganda, Journal of Applied Sciences and Environmental Management, ISSN 1119-8362, 15(1), 167–173 (2010).