MODELLING CHLORINE DECAY IN DRINKING WATER MAINS

2008 ◽  
Vol 7 (6) ◽  
pp. 737-741 ◽  
Author(s):  
Diana Robescu ◽  
Nicolae Jivan ◽  
Dan Robescu
Keyword(s):  
Drinking Water ◽  
Water Mains ◽  
Chlorine Decay

Determination of Hg(II) in drinking water by atomic absorption spectrometry - Cold vapour method after concentration by column extraction chromatography

1984 ◽  
Vol 49 (5) ◽  
pp. 1134-1139 ◽  
Author(s):  
Zdeněk Šmejkal ◽  
Jitka Tauferová ◽  
Mária Madová ◽  
Zlatica Teplá
Keyword(s):  
Drinking Water ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Extraction Chromatography ◽  
Absorption Spectrometry ◽  
Average Yield ◽  
Water Mains ◽  
Cold Vapour ◽  
Column Extraction

The method describes concentration of mercury in samples of drinking water from water mains with Hg concentration above 1.0 . 10-7 g l-1 (5.0 . 10-10mol l-1) by means of extraction chromatography on a column packed with a carrier Synachrom E-5 wetted with saturated solution of bis(diethyldithiocarbamate)copper(II) complex in 1 : 1 mixture 1,2-dichlorobenzene + cyclohexane. After elution with 3.0 mol l-1 HCl the mercury concentration in the eluate is determined by atomic absorption spectrometry - cold vapour method. Average yield of the mercury separation from the model solutions was 95.8%.

Dependency of bulk chlorine decay rates on flow velocity in water distribution networks

2003 ◽  
Vol 3 (1-2) ◽  
pp. 209-214 ◽  
Author(s):  
J. Menaia ◽  
S.T. Coelho ◽  
A. Lopes ◽  
E. Fonte ◽  
J. Palma
Keyword(s):  
Drinking Water ◽  
Flow Velocity ◽  
Distribution Systems ◽  
Distribution Networks ◽  
Decay Rates ◽  
Decay Kinetics ◽  
Decay Rate Constant ◽  
Chlorine Residual ◽  
Chlorine Decay ◽  
Static Conditions

Understanding chlorine residual decay kinetics and the factors that influence them are essential for such current tasks as siting chlorination facilities, dosage optimisation, choice of sampling locations and frequencies, and general design and operational control of drinking water networks, increasingly accomplished with the help of simulation models. Available constants for bulk chlorine decay are typically determined under static conditions. However, as for all fast reactions in water flows, chlorine consumption rates in drinking water pipes may be influenced by the existing mixing regimes, a function of flow turbulence, which is primarily controlled by flow velocity and pipe diameter. Flow velocities vary greatly in space and time in water transmission and distribution systems; pipe diameters are seldom uniform. Although both variables are readily available in the currently available network analysis simulators that implement chlorine models, such variations are not accounted for. Instead, a single preset decay rate constant is generally used for describing chlorine residual consumption throughout an entire system. In addition to highlighting how negligible PVC pipe wall chlorine consumption is, as such, this paper presents experimental evidence of a significant correlation between pipe flow velocity and bulk chlorine decay rates, and proposes a simple but effective approach to implement this dependency in current simulators.

Chlorine decay and trihalomethane formation following ferrate(VI) preoxidation and chlorination of drinking water

Chemosphere ◽  
2017 ◽  
Vol 187 ◽  
pp. 413-420 ◽  
Author(s):  
Cong Li ◽  
Feng Luo ◽  
Feilong Dong ◽  
Jingguo Zhao ◽  
Tuqiao Zhang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Chlorine Decay

Role of drinking water biofilms on residual chlorine decay and trihalomethane formation: An experimental and modeling study

2018 ◽  
Vol 642 ◽  
pp. 516-525 ◽  
Author(s):  
Jianeng Xu ◽  
Conghui Huang ◽  
Xiaoyang Shi ◽  
Shengkun Dong ◽  
Baoling Yuan ◽  
...  
Keyword(s):  
Drinking Water ◽  
Residual Chlorine ◽  
Chlorine Decay ◽  
Modeling Study

The role of biofilms in the mobilisation of polycyclic aromatic hydrocarbons (PAHs) from the coal-tar lining of water pipes

2000 ◽  
Vol 41 (4-5) ◽  
pp. 279-285 ◽  
Author(s):  
M. Maier ◽  
D. Maier ◽  
B.J. Lloyd
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Coal Tar ◽  
Drinking Water Distribution Systems ◽  
Water Pipes ◽  
Real Distribution ◽  
Water Mains ◽  
Drinking Water Distribution ◽  
Polycyclic Aromatic

The influence of biofilm formation on the coal-tar lining of water pipes in drinking water distribution systems was investigated in batch experiments as well as in a continuously flown circular reactor system. The nutrient source for the growth of the biofilm was only the drinking water and the coal-tar coating on the slides. The growth and existence of the biofilm was examined using different techniques. Leaching experiments showed clearly that the biofilm has protective characteristics because enhanced PAH concentrations could be detected after the removal of the biofilm from the slides. Moreover, the dosage of chlorine as a disinfectant during the reactor experiments gave indication that the chlorination resulted in a destabilisation of the biofilm which lead to elevated PAH concentrations. The results are in correspondence with observations made in real distribution systems where enhanced PAH concentrations were observed during disinfection processes. The examination of coal-tar coated water mains revealed that in addition to the protective effect of a biofilm a vast amount of the PAHs was adsorbed on particles embedded in the biofilm, e.g. from the iron oxidising bacteria Gallionella.

scholarly journals Relationship between chlorine decay and temperature in the drinking water

MethodsX ◽  
2020 ◽  
Vol 7 ◽  
pp. 101002
Author(s):  
Fernando García-Ávila ◽  
Carlos Sánchez-Alvarracín ◽  
Manuel Cadme-Galabay ◽  
Julio Conchado-Martínez ◽  
George García-Mera ◽  
...  
Keyword(s):  
Drinking Water ◽  
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.

Evaluation of Chlorine Decay in Drinking Water Systems for Different Flow Conditions: From Theory to Practice

2009 ◽  
Vol 24 (4) ◽  
pp. 815-834 ◽  
Author(s):  
Helena M. Ramos ◽  
D. Loureiro ◽  
A. Lopes ◽  
C. Fernandes ◽  
D. Covas ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Systems ◽  
Flow Conditions ◽  
Theory To Practice ◽  
Chlorine Decay ◽  
Drinking Water Systems
Sign in / Sign up

Export Citation Format

Share Document