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.

Robust booster chlorination in water distribution systems: design and operational perspectives under uncertainty

2019 ◽  
Vol 68 (6) ◽  
pp. 399-410
Author(s):  
Denis Nono ◽  
Innocent Basupi
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Systems Design ◽  
Nsga Ii ◽  
Chlorine Disinfection ◽  
Uncertain Network ◽  
Network Operations ◽  
Booster Chlorination ◽  
Injection Rates

Abstract Booster chlorination designs have been widely based on predefined (deterministic) network conditions and they perform poorly under uncertainty in water distribution systems (WDSs). This paper presents a scenario-based robust optimisation approach which was developed to obtain booster chlorination designs that withstand uncertain network operations and water demand conditions in the WDSs. An optimisation problem was formulated to minimise mass injection rates and the risk of chlorine disinfection. This problem was solved by a non-dominated sorting genetic algorithm (NSGA-II). The proposed approach was demonstrated using the Phakalane network in Botswana. The results present robust booster chlorination (RBC) designs, which indicate the number of boosters, locations and injection rates in the network. The performance of RBC designs evaluated under uncertainty reveals lower risks of chlorine disinfection compared to deterministic-based designs. The proposed approach obtains booster chlorination designs that respond better to uncertainty in the operations of WDSs.

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.

scholarly journals Multiobjective contaminant response modeling for water distribution systems security

2008 ◽  
Vol 10 (4) ◽  
pp. 267-274 ◽  
Author(s):  
Ami Preis ◽  
Avi Ostfeld
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Public Awareness ◽  
Water Distribution Systems ◽  
Evolutionary Model ◽  
Water Supply Systems ◽  
Nsga Ii ◽  
Drinking Water Distribution Systems ◽  
Conflicting Objectives ◽  
Operational Activities

Following the events of 9/11/2001 in the US, the world public awareness to possible terrorist attacks on water supply systems has increased significantly. The security of drinking water distribution systems has become a foremost concern around the globe. Water distribution systems are spatially diverse and thus are inherently vulnerable to intentional contamination intrusions. In this study, a multiobjective optimization evolutionary model for enhancing the response against deliberate contamination intrusions into water distribution systems is developed and demonstrated. Two conflicting objectives are explored: (1) minimization of the contaminant mass consumed following detection, versus (2) minimization of the number of operational activities required to contain and flush the contaminant out of the system (i.e. number of valves closure and hydrants opening). Such a model is aimed at directing quantitative response actions in opposition to the conservative approach of entire shutdown of the system until flushing and cleaning is completed. The developed model employs the multiobjective Non-Dominated Sorted Genetic Algorithm–II (NSGA-II) scheme, and is demonstrated using two example applications.

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.

Chlorine-age based booster chlorination optimization in water distribution network considering the uncertainty of residuals

2018 ◽  
Vol 19 (3) ◽  
pp. 796-807
Author(s):  
Kunlun Xin ◽  
Xiao Zhou ◽  
Hao Qian ◽  
Hexiang Yan ◽  
Tao Tao
Keyword(s):  
Water Distribution ◽  
Distribution Network ◽  
Real Life ◽  
Water Distribution Network ◽  
Optimal Location ◽  
Practical Application ◽  
Water Age ◽  
Time Consumption ◽  
Booster Chlorination ◽  
Chlorine Residuals

Abstract Booster chlorination has been applied by many utilities for better chlorine-residual maintenance. In this paper, a new water-age based method for optimal location and dosage of booster disinfection has been proposed, as well as an uncertainty analysis of chlorine residuals. Chlorine-age, a novel indicator of water quality, is firstly introduced based on water age. By minimizing the total chlorine-age of nodes in a water distribution network (WDN), a new model for optimal booster location is proposed. The chlorine-age based model is independent of chlorine-decay simulation, and therefore avoids the complexity of obtaining kinetic parameters and prevents misleading results caused by inaccurate simulation of chlorine residuals. The uncertainties of chlorine residuals increase along with the distance and time consumption for delivering water. In this study, chlorine-age is employed to measure the uncertainties of nodal residuals, and optimal chlorine dosage is calculated considering the uncertainties. The proposed method has been tested on an example network and a real-life network to illustrate its validity and applicability. The results have shown that the method is feasible and reliable in practical application.

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