Sampling Design for Calibration of Hydraulic and Chlorine Decay Models of Water Distribution Systems

2016 ◽  
Author(s):  
Denis Nono ◽  
Philimon T Odirile ◽  
Bhagabat P. Parida ◽  
Martine Nyeko
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Sampling Design ◽  
Water Distribution Systems ◽  
Chlorine Decay

Prediction of chlorine and trihalomethanes concentration profile in bulk drinking water distribution systems from laboratory data

2003 ◽  
Vol 3 (1-2) ◽  
pp. 239-246 ◽  
Author(s):  
G. Kastl ◽  
I. Fisher ◽  
V. Jegatheesan ◽  
J. Chandy ◽  
K. Clarkson
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Laboratory Data ◽  
Water Distribution Systems ◽  
Optimum Level ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
Chlorine Decay

Nearly all drinking water distribution systems experience a “natural” reduction of disinfection residuals. The most frequently used disinfectant is chlorine, which can decay due to reactions with organic and inorganic compounds in the water and by liquid/solids reaction with the biofilm, pipe walls and sediments. Usually levels of 0.2-0.5 mg/L of free chlorine are required at the point of consumption to maintain bacteriological safety. Higher concentrations are not desirable as they present the problems of taste and odour and increase formation of disinfection by-products. It is usually a considerable concern for the operators of drinking water distribution systems to manage chlorine residuals at the “optimum level”, considering all these issues. This paper describes how the chlorine profile in a drinking water distribution system can be modelled and optimised on the basis of readily and inexpensively available laboratory data. Methods are presented for deriving the laboratory data, fitting a chlorine decay model of bulk water to the data and applying the model, in conjunction with a simplified hydraulic model, to obtain the chlorine profile in a distribution system at steady flow conditions. Two case studies are used to demonstrate the utility of the technique. Melbourne’s Greenvale-Sydenham distribution system is unfiltered and uses chlorination as its only treatment. The chlorine model developed from laboratory data was applied to the whole system and the chlorine profile was shown to be accurately simulated. Biofilm was not found to critically affect chlorine decay. In the other case study, Sydney Water’s Nepean system was modelled from limited hydraulic data. Chlorine decay and trihalomethane (THM) formation in raw and treated water were measured in a laboratory, and a chlorine decay and THM model was derived on the basis of these data. Simulated chlorine and THM profiles agree well with the measured values available. Various applications of this modelling approach are also briefly discussed.

The Effect of Membrane Treatment on Chlorine Decay and Trihalomethanes Formation in Water Distribution Systems

2013 ◽  
Vol 316-317 ◽  
pp. 703-706
Author(s):  
Tao Tao Zhao ◽  
Cong Li ◽  
Hong Liang Yu ◽  
Zi Long Wang ◽  
Ba Yi Er Minda ◽  
...  
Keyword(s):  
Reaction Time ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Clear Understanding ◽  
Exponential Relationship ◽  
Chlorine Decay ◽  
Membrane Treatment ◽  
Kinetics Of ◽  
Trihalomethanes Formation

The experiment was carried out to measure the effect of membrane treatment on the kinetics of chlorine decay in PE pipes in the water distribution systems. The results revealed that water had the potential to form halomethane compounds with chloroform being the most dominant. The formation of THMs is no longer relatively exponential relationship with the reaction time, but also decided by complex elements, including DOC, pH, conductivity, flow rate, and several other indexes. Since Chloroform (CHCl3) has the maximum concentration of the four THMs, clear understanding of its causes, pathway and mechanism will help to regulate and solve the THMs problem.

scholarly journals Analysis of water quality characteristic for water distribution systems

2018 ◽  
Vol 9 (2) ◽  
pp. 152-162
Author(s):  
Yumin Wang ◽  
Guangcan Zhu ◽  
Zhonglian Yang
Keyword(s):  
Water Quality ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Quality Characteristic ◽  
Residual Chlorine ◽  
Pipe Length ◽  
Water Quality Characteristic ◽  
Chlorine Decay ◽  
Single Pipe

Abstract Since governments all over the world are paying more attention to water quality in water distribution systems (WDS), a method based on mass balance and first-order chlorine decay model was proposed to assess the efficiency of WDS involving water quality (represented by residual chlorine). The concepts of surplus chlorine factor (S) for nodes in individual pipes and comprehensive surplus chlorine factor (CS) for nodes in WDS were put forward to represent the water quality characteristic of nodes in WDS based on the assumption that the structure of the pipe network and quantity of chlorine dose are definite. The proposed method was applied to two examples of WDS and sensitivity analysis regarding chlorine decay coefficient (k0) was discussed. The results indicated that values of CS for nodes in WDS are affected by the inflow of nodes, which is determined by water demand and pipe length from water sources to nodes. In addition, the value of CS increases with k0 when the inflow of the node is larger than the optimized inflow. The results verified that the deduction of S for a single pipe can be generalized to WDS, and can measure the water quality characteristics for nodes in WDS easily.

scholarly journals Integrating booster chlorination and operational interventions in water distribution systems

2018 ◽  
Vol 20 (5) ◽  
pp. 1025-1041
Author(s):  
Denis Nono ◽  
Innocent Basupi ◽  
Phillimon T. Odirile ◽  
Bhagabat P. Parida
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Age ◽  
Nsga Ii ◽  
Chlorine Disinfection ◽  
Periodic Monitoring ◽  
Chlorine Decay ◽  
Booster Chlorination ◽  
Chlorine Residuals

Abstract Booster chlorination reduces the risks associated with conventional disinfection such as high chlorine residuals near water treatment plants and low chlorine residuals at remote parts of water distribution systems (WDSs). Network operational interventions have a significant influence on water age and chlorine decay in WDSs. In this study, an integrated booster chlorination method is developed to obtain optimal designs that reduce the risks associated with conventional disinfection in WDSs. The method integrates booster chlorination with network operational interventions to reduce water age and improve chlorine residuals in WDSs. A multi-objective booster optimisation problem is formulated based on risks associated with chlorine disinfection and solved using a non-dominated sorting genetic algorithm (NSGA-II) and the EPANET hydraulic and water quality solver. The proposed methodology was tested in the Phakalane WDS in Botswana. The integrated booster disinfection method significantly improves chlorine residuals in a WDSs with lower mass and cost of chlorine than conventional disinfection. Furthermore, the study indicates that integrated booster chlorination designs are influenced by changes in network conditions such as water demand and chlorine decay coefficients. Therefore, periodic monitoring of these parameters is required to ensure that the acceptable performance of chlorine boosters in WDSs is maintained.

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