scholarly journals Evaluation of chlorine decay models under transient conditions in a water distribution system

2017 ◽  
Vol 19 (4) ◽  
pp. 522-537 ◽  
Author(s):  
Hyunjun Kim ◽  
Sanghyun Kim
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Chlorine Concentration ◽  
Transient Conditions ◽  
Hydraulic Conditions ◽  
Transient Events ◽  
Chlorine Decay ◽  
The Impact ◽  
Unsteady Conditions

Residual chlorine concentration decreases along distribution networks because of factors such as water quality, physical properties of the pipeline, and hydraulic conditions. Hydraulic conditions are primarily governed by transient events generated by valve modulation or pumping action. We investigate the impact of transient events on the rate of chlorine decay under various flow conditions. To comprehensively compare the performance of existing chlorine models, 14 candidate models for chlorine concentration were used under various transient conditions. Two-dimensional (2D) transient flow analysis was conducted to investigate the unknown processes of chlorine decay under transient conditions. General formulations for modeling chlorine decay were used to comprehensively study the decay under unsteady conditions and to effectively incorporate the impact of transients into generic model structures. The chlorine decay patterns in the constructed water distribution system were analyzed in the context of transient events. Linear relationships between the model parameters and the frequency of transient events were determined under unsteady conditions, and the impact of turbulence intensity was successfully incorporated into model parameter evaluations. The modeling results from 2D transient analysis exhibit similar predictability as those obtained from calibration using the genetic algorithm.

scholarly journals Chlorine Decay Simulation in Water Distribution System Using EPANET

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Nur Shazwani Muhammad ◽  
◽  
Siew Ming Shin ◽  
Jazuri Abdullah ◽  
◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Treatment Plant ◽  
Extended Period ◽  
Temporal Variations ◽  
Chlorine Concentration ◽  
World Health ◽  
Chemical Components ◽  
Chlorine Decay

Chlorine is used as a disinfectant in the water treatment process so that treated water is delivered safely to consumers. However, chlorine concentration decays when water flows from the treatment plant to the supply point, due to the reaction with natural organic matter and the inner surface of the pipe. Low chlorine concentration may encourage bacteria re-growth, while high chlorine concentration can result in the formation of harmful chemical components. Therefore, this study aims to simulate the complex process of chlorine decay using EPANET. This exercise enables the determination the chlorine concentration dosage required to maintain the desired requirement given by the World Health Organization (WHO) and the Ministry of Health, Malaysia (MOH). A successful model with an extended period of simulations of 72 hours enable the mapping of spatial and temporal variations of flow and residue chlorine concentrations at all links and nodes. Constant chlorine dosage of 3.96 mg/l at node R1 has successfully satisfy the requirement given by WHO and MOH. The residue chlorine concentrations at the nodes and links in the water distribution system also depends on the water usage at node 5, the size of service reservoir and service tank and distance from the reservoir.

Variations of DBPs precursors according to location within the distribution system

2009 ◽  
Vol 9 (4) ◽  
pp. 413-421
Author(s):  
C. Beaulieu ◽  
M. J. Rodriguez ◽  
J.-B. Sérodes
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Spatial Behavior ◽  
Haloacetic Acids ◽  
Formation Potential ◽  
The Impact ◽  
By Products

Little information is available on the evolution of remaining organic matter (ROM) in a water distribution system (WDS) and its impact on the generation of disinfection by-products (DBPs). This research involves the characterization, through sample fractionation processes and experimental chlorination tests, of the reactivity of DBP precursors occurring within a WDS. The study is based on samples collected in various locations of a WDS during a complete year. For each sample, six fractions were generated to determine their potential for formation of trihalomethanes (THMs) and haloacetic acids (HAAs). Fractionation processes on ROM demonstrated that the spatial behavior of precursors for THMs differs from that for precursors of HAAs. In addition, experimental chlorination tests showed that the reactivity of the investigated fractions, in terms of DBP formation potential (DBPfp), was different from each other according to location in the WDS. DBPfp for the studied fractions changed drastically during water treatment. However, changes of DBPfp for fractions were relatively low between the beginning and the extremity of the distribution system. Since the results of this research confirm that the ability to produce DBPs is related to the nature of the fractions, they could be useful to evaluate the impact of re-chlorination on DBP formation in a WDS.

Investigation of the Impact of Anti-Negative Pressure Facility on a Water Distribution System

2013 ◽  
Vol 316-317 ◽  
pp. 719-722
Author(s):  
Huan Huan Wang ◽  
Shu Ming Liu ◽  
Fan Lin Meng ◽  
Lu Bai
Keyword(s):  
Water Supply ◽  
Negative Pressure ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Simulation Method ◽  
Water Tank ◽  
Research Activities ◽  
High Level ◽  
The Impact

High level water tank is a commonly used facility to satisfy water demand for people living in high building, which is also the so-called secondary water supply system (SWSS) in China. Due to lack of maintenance, water quality problem has been frequently reported in the SWSS. In the last few decades, anti-negative pressure facility (ANPF) has emerged as a revolutionary approach for solving the pollution in the SWSS. ANPF makes good use of the municipal pipeline pressure, which is the improvement of traditional water supply. However, most of recent research activities mainly focus on the influence of part of water distribution system (WDS). In this paper, the software of EPANET has been applied in the SWSS calculation and simulation. Besides that, the SWSS with ANPF simulation method is proposed to evaluate the effect of other all nodes pressure in the WDS using hydraulic model. As the cases study, the paper analyzed two WDSs with ANPF. After simulation of the SWSS, the result of WDS, which is smaller, indicates that 6 out of the 9 nodes are affected with ANPF and that of WDS, which is larger, demonstrates that 37 out of the 41 nodes are affected and the affected nodes are focused on the confluent of pipes, especially around the ANPF.

scholarly journals An Improved Water Distribution System Chlorine Decay Model Using EPANET MSX

2012 ◽  
Author(s):  
Walter M. Grayman ◽  
◽  
Sudhir Kshirsagar ◽  
Melixa Rivera-Sustache ◽  
Mark Ginsberg ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Decay Model ◽  
Chlorine Decay

Molecular characterization of bacteria inhabiting a water distribution system simulator

2003 ◽  
Vol 47 (5) ◽  
pp. 149-154 ◽  
Author(s):  
J.W. Santo Domingo ◽  
M.C. Meckes ◽  
J.M. Simpson ◽  
B. Sloss ◽  
D.J. Reasoner
Keyword(s):  
16S Rdna ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution System ◽  
Heterotrophic Bacteria ◽  
Feed Water ◽  
Ammonia Oxidizing Bacteria ◽  
16S Rdna Pcr ◽  
The Impact

The objective of this study was to monitor the impact of chlorination and chloramination treatments on heterotrophic bacteria (HB) and ammonia-oxidizing bacteria (AOB) inhabiting a water distribution system simulator. HB densities decreased while AOB densities increased when chloramine was added. AOB densities decreased below detection limits after the disinfection treatment was switched back to chlorination. The presence of AOB was confirmed using a group-specific 16S rDNA-PCR method. 16S rDNA sequence analysis showed that most bacterial isolates from feed water, discharge water, and biofilm samples were α-Proteobacteria or β-Proteobacteria. The latter bacterial groups were also numerically dominant among the sequences recovered from water and biofilm 16S rDNA clone libraries. The relative frequency of each culturable bacterial group was different for each sample examined. Denaturing gradient gel electrophoresis analysis of total community 16S rDNA genes showed notable differences between the microbial community structure of biofilm samples and feed water. The results of this study suggest that disinfection treatments could influence the type of bacterial community inhabiting water distribution systems.

Sign in / Sign up

Export Citation Format

Share Document