ISSN: 2375-3846
American Journal of Science and Technology  
Manuscript Information
 
 
Modeling of Chlorine Decay Rates in Distribution Systems Based on Initial Chlorine, Reactant Concentrations and Their Distributions
American Journal of Science and Technology
Vol.3 , No. 3, Publication Date: May 13, 2016, Page: 53-62
2689 Views Since May 13, 2016, 2117 Downloads Since May 13, 2016
 
 
Authors
 
[1]    

Ababu T. Tiruneh, Department of Environmental Health Science, University of Swaziland, Mbabane, Swaziland.

[2]    

Amos O. Fadiran, Department of Chemistry, University of Swaziland, Kwaluseni, Swaziland.

[3]    

Stanley J. Nkambule, Department of Environmental Health Science, University of Swaziland, Mbabane, Swaziland.

[4]    

Lwazi M. Zwane, Department of Environmental Health Science, University of Swaziland, Mbabane, Swaziland.

 
Abstract
 

A mathematical model for determining the rate of variation of bulk decay rates of chlorine residuals is proposed taking into account factors such as the initial chlorine concentration, the concentrations of reactants and their relative distribution. The theoretical model we built in this research clearly shows that the variation of the bulk decay coefficient with initial chlorine concentrations can be modelled mathematically as a second order reaction which can be easily integrated in modelling programs such as the EPANET. Experiments were carried out for determining the bulk decay rate of chlorine residuals at different initial chlorine doses and the data adequately fit the developed model. We also developed chlorine decay mathematical models for the variation of the rate of reaction of both time-varying as well as time-averaged reaction rates. It is shown that the parameters affecting the variation of reaction rate include: The chlorine concentration and the molar concentration of the low concentration reactants as expressed through the ratio of arithmetic mean to the harmonic mean of the reactant concentrations. For the time-averaged model that can be used in modelling programs based on first order reactions, the time variation of the rate of reaction was additionally influenced by the aggregate (total) reactant concentrations.


Keywords
 

Chlorine Residual, Bulk Decay Rate, Water Quality, Water Distribution, Reaction Rate, Initial Chlorine Concentration, Variable Rate Chlorine Decay


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