Modelling the chlorine decay process in a distribution network using a pilot system

2014 ◽  
Vol 9 (4) ◽  
pp. 534-550
Author(s):  
R. Buamah ◽  
K. Akodwaa-Boadi ◽  
M. Paintsil ◽  
E. K. Baah-Ennumh ◽  
A. A. Adjaottor
Keyword(s):  
Cast Iron ◽  
Distribution System ◽  
Water Distribution ◽  
Batch Reactor ◽  
Distribution Network ◽  
Bulk Water ◽  
Residual Chlorine ◽  
Pipe Material ◽  
Bulk Fluid ◽  
Chlorine Decay

Chlorine is one of the many disinfectants used to ensure bacteriological safety of drinking water. Usually residual chlorine is maintained within the distribution network to combat any probable re-contamination of the distributed water. This residual free chlorine, however, decays in water due to its reaction with the bulk water and the pipe material or deposits on the pipe walls. This study aimed at determining and modelling chlorine decay in the Kumasi water distribution network (KWDN) and determined locations where residual chlorine boosting is necessary. A double-jacketed batch reactor and a constructed pilot distribution system (PDS) were used to determine the bulk and wall decay coefficients. The PDS was run using aged PVC pipes (15–20 years), asbestos concrete pipes (40–50 years) and cast iron pipes (84 years) that have been in use in the KWDN. The SynerGEE® hydraulic model was used to identify the ‘zero chlorine’ points and predict top-up quantities. The bulk decay coefficient was found to be 0.053 h−1 within 8 hours at 26 °C and the residual chlorine decayed within the bulk fluid by 32–34% of its initial dose. Under the conditions tested, the cast iron pipes had the highest overall decay coefficients (K). Five locations within the network were identified as probable chlorine boosting points).

scholarly journals Residual Chlorine Decay in Juja Water Distribution Network using EPANET Model

2019 ◽  
Vol 9 (1) ◽  
pp. 332-334 ◽  
Keyword(s):  
Water Distribution ◽  
Distribution Network ◽  
Treatment Plant ◽  
Water Distribution Network ◽  
Residual Chlorine ◽  
Simulation Tool ◽  
First Order ◽  
Water Company ◽  
Field Samples ◽  
Chlorine Decay

The current study was carried out to analyze the residual chlorine decay analysis within the existing Juja water distribution network. The study used EPANET as a simulation tool. From the field samples, the first-order bulk decay coefficient Kb was found equal to - 0.04 . The wall coefficient Kw was assumed to - 4.0 mg/ /day as guided by literature. The analysis shows that the entire supply area of the existing distribution network faces higher residual chlorine concentration (0.70 to 0.8 mg/l) from 9 am. The study recommended the reducing of the initial chlorine added at the treatment plant and the optimization of the network, which will provide a proper residual chlorine dosage to reduce Juja consumers exposure to health risk and also to be economically reasonable for the water company in charge

Application of Artificial Neural Network for Reducing of Chlorine Residual Concentration in Water Distribution Network

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
Jayong Koo ◽  
Toyono Inakazu ◽  
Akira Koizumi ◽  
Yasuhiro Arai ◽  
Kyoungpil Kim ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Residual Chlorine ◽  
Trial And Error ◽  
Ann Model ◽  
Residual Concentration ◽  
Dead End

It is difficult to estimate residual chlorine at the dead-end area of the water distribution network because chlorine consumption is influenced by various factors. Therefore, there are many water utilities that control the amounts of chlorine in reservoirs using empirical trial-and-error methods to maintain safe levels of residual chlorine in the distribution system. In this study, an ANN model of residual chlorine concentration is proposed which could be used to reduce in chlorine use in water distribution system. The ANN model with best performance was selected by training and verification. The five scenarios for the reduction in chlorine use were analyzed by setting the input chlorine as low as 0.05~0.25 mg/L compared with the input chlorine observed in the time series. Case 4 is the best to be satisfied with the input condition (0.4 mg/L or more) and output condition (0.34 mg/L or more) at the same time. It is possible to reduce chlorine in use up to 0.2 mg/L in the maximum amount.

scholarly journals Water quality trend analysis in a citywide water distribution system

2021 ◽  
Author(s):  
Keya Chowdhury ◽  
Aysha Akter
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Water Distribution ◽  
Oxygen Demand ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Residual Chlorine ◽  
Secondary Source ◽  
Pipe Material ◽  
Rapid Urbanization

Abstract Rapid urbanization poses challenges to meet the increased water supply demands. Apart from the quantity, the distributed water quality often fails to meet the permissible level. This study aimed to conduct a citywide spatio-temporal variation of water quality parameters. Water sampling points were selected by applying the Analytical Hierarchical Process (AHP) technique using ArcGIS considering pipe leakage, source water quality, pipe age, and pipe materials. The Chattogram city comprises 397 km of pipes; pipe material distribution shows 71.28% PVC, 20.94% asbestos, 5.16% mild steel, 2.17% ductile, and 0.45% cast iron. The citywide pipe network was established in 1963; 20.87% of pipes aged over 30 years, 15.07% 20–30 years, 26.38% 10–20 years, and 37.68% pipelines are relatively new, i.e., within 0–10 years. Eight water quality parameters, i.e., pH, temperature, turbidity, biochemical oxygen demand after five days (BOD5), total coliform, fecal coliform, chloride, and residual chlorine, were collected from the secondary source cross-checked by field survey. Computation of the Water Quality Index (WQI) was interpolated using Inverse Distance Weighted (IDW) method to generate a WQI map. Thus, this study could be a basis to improve the treatment system and proper distribution network maintenance.

scholarly journals The Impact of Pipe Material on the Diversity of Microbial Communities in Drinking Water Distribution Systems

2021 ◽  
Vol 12 ◽  
Author(s):  
Debbie Lee ◽  
Gennaro Calendo ◽  
Kristin Kopec ◽  
Rebekah Henry ◽  
Scott Coutts ◽  
...  
Keyword(s):  
Drinking Water ◽  
Cast Iron ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Pipe Material ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution ◽  
The Mean ◽  
The Impact

As many cities around the world face the prospect of replacing aging drinking water distribution systems (DWDS), water utilities must make careful decisions on new pipe material (e.g., cement-lined or PVC) for these systems. These decisions are informed by cost, physical integrity, and impact on microbiological and physicochemical water quality. Indeed, pipe material can impact the development of biofilm in DWDS that can harbor pathogens and impact drinking water quality. Annular reactors (ARs) with cast iron and cement coupons fed with chloraminated water from a municipal DWDS were used to investigate the impact of pipe material on biofilm development and composition over 16 months. The ARs were plumbed as closely as possible to the water main in the basement of an academic building to simulate distribution system conditions. Biofilm communities on coupons were characterized using 16S rRNA sequencing. In the cast iron reactors, β-proteobacteria, Actinobacteria, and α-proteobacteria were similarly relatively abundant (24.1, 22.5, and 22.4%, respectively) while in the cement reactors, α-proteobacteria and Actinobacteria were more relatively abundant (36.3 and 35.2%, respectively) compared to β-proteobacteria (12.8%). Mean alpha diversity (estimated with Shannon H and Faith’s Phylogenetic Difference indices) was greater in cast iron reactors (Shannon: 5.00 ± 0.41; Faith’s PD: 15.40 ± 2.88) than in cement reactors (Shannon: 4.16 ± 0.78; Faith’s PD: 13.00 ± 2.01). PCoA of Bray-Curtis dissimilarities indicated that communities in cast iron ARs, cement ARs, bulk distribution system water, and distribution system pipe biofilm were distinct. The mean relative abundance of Mycobacterium spp. was greater in the cement reactors (34.8 ± 18.6%) than in the cast iron reactors (21.7 ± 11.9%). In contrast, the mean relative abundance of Legionella spp. trended higher in biofilm from cast iron reactors (0.5 ± 0.7%) than biofilm in cement reactors (0.01 ± 0.01%). These results suggest that pipe material is associated with differences in the diversity, bacterial composition, and opportunistic pathogen prevalence in biofilm of DWDS.

scholarly journals Effects of chlorine and pipe material on biofilm development and structure in a reclaimed water distribution system

2012 ◽  
Vol 12 (3) ◽  
pp. 362-371 ◽  
Author(s):  
Haibo Wang ◽  
Xuexiang Hu ◽  
Chun Hu
Keyword(s):  
Cast Iron ◽  
Distribution System ◽  
Water Distribution ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Water Distribution System ◽  
Reclaimed Water ◽  
Pipe Material ◽  
Uncultured Bacterium ◽  
Gradient Gel Electrophoresis ◽  
Biofilm Development

The effects of chlorine and pipe material on biofilm development and structure were studied in a model reclaimed water distribution system using annular reactors (ARs). The initial chlorine dose of influents in ARs with polycarbonate pipes and cast iron pipes was 3.59 and 10.15 mg/L, respectively, which could maintain the reclaimed water quality (HPC 102–103 CFU/mL). The chlorine and pipe material influenced the bacterial community. Biofilms formed faster and to a greater extent in ARs with cast iron coupons (HPC 107 CFU/cm2) compared to those with polycarbonate coupons (HPC 105 CFU/cm2). Using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analysis, it was found that Gammaproteobacteria were prevalent in all cases with polycarbonate pipes, whereas with cast iron pipes microbial populations were affiliated with the phylum Proteobacteria, including the classes Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Deltaproteobacteria, followed by the phyla Bacteroidetes and uncultured bacterium.

Application of two approaches to model chlorine residuals in Severn Trent Water Ltd (STW) distribution systems

1997 ◽  
Vol 36 (5) ◽  
pp. 317-324 ◽  
Author(s):  
M.J. Rodriguez ◽  
J.R. West ◽  
J. Powell ◽  
J.B. Sérodes
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Residual Chlorine ◽  
Ann Model ◽  
Order Model ◽  
First Order ◽  
Chlorine Decay ◽  
Artificial Neural Network Ann ◽  
Key Parameter

Increasingly, those who work in the field of drinking water have demonstrated an interest in developing models for evolution of water quality from the treatment plant to the consumer's tap. To date, most of the modelling efforts have been focused on residual chlorine as a key parameter of quality within distribution systems. This paper presents the application of a conventional approach, the first order model, and the application of an emergent modelling approach, an artificial neural network (ANN) model, to simulate residual chlorine in a Severn Trent Water Ltd (U.K.) distribution system. The application of the first order model depends on the adequate estimation of the chlorine decay coefficient and the travel time within the system. The success of an ANN model depends on the use of representative data about factors which affect chlorine evolution in the system. Results demonstrate that ANN has a promising capacity for learning the dynamics of chlorine decay. The development of an ANN appears to be justifiable for disinfection control purposes, in cases when parameter estimation within the first order model is imprecise or difficult to obtain.

scholarly journals Effects of disinfectant and biofilm on the corrosion of cast iron pipes in a reclaimed water distribution system

2012 ◽  
Vol 46 (4) ◽  
pp. 1070-1078 ◽  
Author(s):  
Haibo Wang ◽  
Chun Hu ◽  
Xuexiang Hu ◽  
Min Yang ◽  
Jiuhui Qu
Keyword(s):  
Cast Iron ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Reclaimed Water

Understanding and forecasting taste-and-odour formation in a drinking water distribution system: case study of Lyon (France)

2009 ◽  
Vol 9 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Elise Corbi ◽  
Valérie Jacquemet ◽  
Alain Quendo ◽  
Francine Manciot ◽  
Adeline Lamy ◽  
...  
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Drinking Water Distribution ◽  
First Results ◽  
Mechanisms Of Formation

Lyon, France has the opportunity to distribute in abundance a groundwater resource with a good quality for drinking water. However, the length and the complexity of the distribution network can lead to consumer complaints in some areas of the water distribution system. In order to improve the organoleptic quality of distributed water, the water supplier wants to get a better understanding of potential taste and odour formation and to succeed in controlling it. Since 2006, activities have been taken with targeted analyses and sensory evaluation of water, taking into account both the consumers' private networks and the citywide distribution network. The first results were focused on the occurrence of bromophenols along the water distribution system, the understanding of the mechanisms of formation of such compounds, as well as their incidence on taste-and-odour events at the consumer's home.

scholarly journals Operational and technical performance of a water distribution network in Oman

2021 ◽  
Author(s):  
Ahmed Al Naamani ◽  
Ahmad Sana
Keyword(s):  
Water Quality ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Capital City ◽  
Operational Performance ◽  
Residual Chlorine ◽  
Quality Performance ◽  
Urban Networks ◽  
Technical Performance

Abstract A water distribution network in an urban area in Muscat region (capital city of Oman) is assessed for operational performance using the widely accepted methodology proposed by International Water Association (IWA). The technical performance of this network was assessed using global performance index methods after modifying the performance levels as per local guidelines. A total of 37 operational performance indicators for the network were selected to carryout assessment. Overall operational performance showed high scores whereas some indicators showed unacceptable performance values. The network showed very high technical performance considering nodal pressures. The lower performance for pipe velocity may be attributed to the fact that the network is currently being utilized by 70% of the population for which it was designed. The residual chlorine levels were within the acceptable range of the Public Authority for Water (PAW) showing a very good performance by virtue of water quality. This study will be useful for the decision makers to assess the operational, technical and water quality performance of urban networks and take actions for improvements.

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