scholarly journals Comparison Between Diffusive and Advective Approach in Quality Analysis of a Real Distribution Network

10.29007/chxk ◽  
2018 ◽  
Author(s):  
Stefania Piazza ◽  
E.J. Mirjam Blokker ◽  
Gabriele Freni ◽  
Valeria Puleo ◽  
Mariacrocetta Sambito

In recent years, the evaluation of water quality in distribution systems has generated enormous interest in the scientific community due to the increasing concentration of population in urban areas and frequent issues connected with supply water quality. Following the wave of bioterrorism subsequent the events of September 11th 2001, a need can be foreseen to seek adequate preventive measures to deal with contamination in water distribution systems that may be related to the accidental contamination and deliberate injection of toxic agents of any origin in the distribution networks. Therefore, it is very important to create a sensor system that detects contamination events in real time, while maintaining the reliability and efficiency of the measurements, limiting the cost of the instrumentation. A reliable monitoring system, for this kind of problems, cannot be deployed without realistic modelling support. The current state-of-the-art in water distribution systems analysis usually adopt a simplified approach to water quality modelling, neglecting dispersion and diffusion and considering simplified reaction kinetics. Even if such simplifications are commonly acceptable in fully turbulent flows, they may take to relevant errors in transition flows with low velocity thus taking to unreliable interpretation of the contamination in complex networks. The present paper aims to compare different modelling approaches to the evaluation of contaminant dispersion in two distribution networks: one laboratory network in which contamination experiments were carried out in a controlled environment (Enna, Italy) and a full-scale real distribution network (Zandvoort, Netherlands).

2021 ◽  
Author(s):  
Jon Kristian Rakstang ◽  
Michael B. Waak ◽  
Marius M. Rokstad ◽  
Cynthia Hallé

<p>Municipal drinking water distribution networks are complex and dynamic systems often spanning many hundreds of kilometers and serving thousands of consumers. Degradation of water quality within a distribution network can be associated to water age (i.e., time elapsed after treatment). Norwegian distribution networks often consist of an intricate combination of pressure zones, in which the transport path(s) between source and consumer is not easily ascertained. Water age is therefore poorly understood in many Norwegian distribution networks. In this study, simulations obtained from a water network model were used to estimate water age in a Norwegian municipal distribution network. A full-scale tracer study using sodium chloride salt was conducted to assess simulation accuracy. Water conductivity provided empirical estimates of salt arrival time at five monitoring stations. These estimates were consistently higher than simulated peak arrival times. Nevertheless, empirical and simulated water age correlated well, indicating that additional network model calibration will improve accuracy. Subsequently, simulated mean water age also correlated strongly with heterotrophic plate count (HPC) monitoring data from the distribution network (Pearson’s R= 0.78, P= 0.00046), indicating biomass accumulation during distribution—perhaps due to bacterial growth or biofilm interactions—and illustrating the importance of water age for water quality. This study demonstrates that Norwegian network models can be calibrated with simple and cost-effective salt tracer studies to improve water age estimates. Improved water age estimation will increase our understanding of water quality dynamics in distribution networks. This can, through digital tools, be used to monitor and control water age, and its impact on biogrowth in the network.</p>


2011 ◽  
Vol 11 (4-5) ◽  
pp. 731-747 ◽  
Author(s):  
MASSIMILIANO CATTAFI ◽  
MARCO GAVANELLI ◽  
MADDALENA NONATO ◽  
STEFANO ALVISI ◽  
MARCO FRANCHINI

AbstractThis paper presents a new application of logic programming to a real-life problem in hydraulic engineering. The work is developed as a collaboration of computer scientists and hydraulic engineers, and applies Constraint Logic Programming to solve a hard combinatorial problem. This application deals with one aspect of the design of a water distribution network, i.e., the valve isolation system design. We take the formulation of the problem by Giustolisi and Savić (2008 Optimal design of isolation valve system for water distribution networks. InProceedings of the 10th Annual Water Distribution Systems Analysis Conference WDSA2008, J. Van Zyl, A. Ilemobade, and H. Jacobs, Eds.) and show how, thanks to constraint propagation, we can get better solutions than the best solution known in the literature for the Apulian distribution network. We believe that the area of the so-calledhydroinformaticscan benefit from the techniques developed in Constraint Logic Programming and possibly from other areas of logic programming, such as Answer Set Programming.


2020 ◽  
Vol 81 (8) ◽  
pp. 1606-1614 ◽  
Author(s):  
M. S. Nyirenda ◽  
T. T. Tanyimboh

Abstract The use of water quality indices to aggregate pollution loads in rivers has been widely studied, with researchers using various sub-indices and aggregation methods. These have been used to combine various quality variables at a sampling point in a river into an overall water quality index to compare the state of water quality in different river reaches. Service reservoirs in a water distribution network, like rivers, have complex mixing mechanisms, are subjected to various water quality variables and are variably sized and sited. Water quality indices and the relevant sub-indices are formulated here and applied to service reservoirs within a water distribution network. This is in an attempt to compare holistically the performance of service reservoirs in solutions of optimisation algorithms with regards to water quality.


2018 ◽  
Vol 4 (12) ◽  
pp. 2080-2091 ◽  
Author(s):  
Isabel Douterelo ◽  
Carolina Calero-Preciado ◽  
Victor Soria-Carrasco ◽  
Joby B. Boxall

This research highlights the potential of whole metagenome sequencing to help protect drinking water quality and safety.


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