scholarly journals Modeling particle transport and discoloration risk in drinking water distribution networks

2017 ◽  
Vol 10 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Joost van Summeren ◽  
Mirjam Blokker
Keyword(s):  
Drinking Water ◽  
Particle Transport ◽  
Distribution Systems ◽  
Water Distribution ◽  
Field Measurements ◽  
Distribution Networks ◽  
Particulate Material ◽  
Turbulent Pipe Flow ◽  
Shear Stresses ◽  
Drinking Water Distribution

Abstract. Discoloration of drinking water is a worldwide phenomenon caused by accumulation and subsequent remobilization of particulate matter in drinking water distribution systems (DWDSs). It contributes a substantial fraction of customer complaints to water utilities. Accurate discoloration risk predictions could improve system operation by allowing for more effective programs on cleaning and prevention actions and field measurements, but are challenged by incomplete understanding on the origins and properties of particles and a complex and not fully understood interplay of processes in distribution networks. In this paper, we assess and describe relevant hydraulic processes that govern particle transport in turbulent pipe flow, including gravitational settling, bed-load transport, and particle entrainment into suspension. We assess which transport mechanisms are dominant for a range of bulk flow velocities, particle diameters, and particle mass densities, which includes common conditions for DWDSs in the Netherlands, the UK, and Australia. Our analysis shows that the theoretically predicted particle settling velocity and threshold shear stresses for incipient particle motion are in the same range as, but more variable than, previous estimates from lab experiments, field measurements, and modeling. The presented material will be used in the future development of a numerical modeling tool to determine and predict the spatial distribution of particulate material and discoloration risk in DWDSs. Our approach is aimed at understanding specific causalities and processes, which can complement data-driven approaches.

scholarly journals Modeling particle transport and discoloration risk in drinking water distribution networks

2017 ◽  
Author(s):  
Joost van Summeren ◽  
Mirjam Blokker
Keyword(s):  
Drinking Water ◽  
Particle Transport ◽  
Distribution Systems ◽  
Water Distribution ◽  
Field Measurements ◽  
Distribution Networks ◽  
Particulate Material ◽  
Turbulent Pipe Flow ◽  
Shear Stresses ◽  
Customer Complaints

Abstract. Discoloration of drinking water is a worldwide phenomenon caused by accumulation and subsequent remobilization of particulate matter in distribution systems (DWDSs). It contributes to a substantial fraction of customer complaints to water utilities. Accurate discoloration risk predictions could improve system operation by allowing for more effective programs on cleaning and prevention actions and field measurements, but are challenged by incomplete understanding on the origins and properties of particles and a complex and not fully understood interplay of processes in distribution networks. In this paper, we assess and describe relevant hydraulic processes that govern particle transport in turbulent pipe flow, including gravitational settling, bed-load transport, and particle entrainment into suspension. We assess which transport mechanisms are dominant for a range of bulk flow velocities, particle diameters, and particle mass densities, which includes common conditions for DWDS in The Netherlands, U.K., and Australia. Our analysis shows that the theoretically predicted particle settling velocity and threshold shear stresses for incipient particle motion are in the same range, but more variable than, previous estimates from lab experiments, field measurements, and modeling. The presented material will be used in the future development of a numerical modeling tool to determine and predict the spatial distribution of particulate material and discoloration risk in DWDSs. Our approach is aimed at understanding specific causalities and processes, which can complement data-driven approaches.

scholarly journals Linking discolouration modelling and biofilm behaviour within drinking water distribution systems

2016 ◽  
Vol 16 (4) ◽  
pp. 942-950 ◽  
Author(s):  
S. Husband ◽  
K. E. Fish ◽  
I. Douterelo ◽  
J. Boxall
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Particulate Material ◽  
Operational Strategies ◽  
Drinking Water Distribution Systems ◽  
Cohesive Properties ◽  
Common Process ◽  
Drinking Water Distribution

High quality drinking water exits modern treatment works, yet water quality degradation such as discolouration continues to occur within drinking water distribution systems (DWDS). Discolouration is observed globally, suggesting a common process despite variations in source, treatment, disinfection and network configurations. The primary cause of discolouration has been identified as mobilisation of particulate material from pipe walls and the verified Prediction of Discolouration in Distribution Systems (PODDS) model uses measurable network hydraulics to simulate this response. In this paper the cohesive properties of discolouration material are explored and it is hypothesised that in simulating the turbidity response, the PODDS model is actually describing the development and cohesive strength behaviour of biofilms. Applying this concept can therefore facilitate a rapid and simple assessment of DWDS biofilm activity. A review of the findings from PODDS studies conducted internationally is presented, focussing on the macro or observable aspects of discolouration. These are compared and contrasted with associated biofilm studies which consider discolouration material at the micro-scale. Combining the results from these (past) studies to improve the understanding of interactions between microbial ecology and discolouration are discussed with a view to DWDS operational strategies that safeguard and optimise drinking water supply.

scholarly journals Accumulation and modeling of particles in drinking water pipe fittings

2012 ◽  
Vol 5 (1) ◽  
pp. 47-57 ◽  
Author(s):  
K. Neilands ◽  
M. Bernats ◽  
J. Rubulis
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Particle Accumulation ◽  
Catchment Areas ◽  
Drinking Water Distribution ◽  
Online Measurements ◽  
Pipe Fittings ◽  
Pipe Geometry

Abstract. The effect of pipe fittings (mainly T-pieces) on particle accumulation in drinking water distribution networks were shown in this work. The online measurements of flow and turbidity for cast iron, polyethylene and polyvinyl chloride pipe sections were linked with analysis of pipe geometry. Up to 0.29 kg of the total amount mobilized in T-pieces ranging from DN 100/100–DN 250/250. The accumulated amount of particles in fittings was defined as J and introduced into the existing turbidity model PODDS (prediction of discoloration in distribution systems) proposed by Boxall et al. (2001) which describes the erosion of particles leading to discoloration events in drinking water network viz sections of straight pipes. However, this work does not interpret mobilization of particles in pipe fittings which have been considered in this article. T-pieces were the object of this study and depending of the diameter or daily flow velocity, the coefficient J varied from 1.16 to 8.02. The study showed that pipe fittings act as catchment areas for particle accumulation in drinking water networks.

scholarly journals Accumulation and modeling of particles in drinking water pipe fittings

2012 ◽  
Vol 5 (1) ◽  
pp. 139-171
Author(s):  
K. Neilands ◽  
M. Bernats ◽  
J. Rubulis
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Water Pipe ◽  
Particle Accumulation ◽  
Drinking Water Distribution ◽  
Online Measurements ◽  
Pipe Fittings ◽  
Pipe Geometry

Abstract. The effect of pipe fittings – mainly T-pieces – on particle accumulation in drinking water distribution networks is shown in this work. The online measurements of flow and turbidity for cast iron, polyethylene and polyvinylchloride pipe sections have been linked with the analysis of pipe geometry. Up to 0.29 kg of the total mass of particles was found to be accumulated in T-pieces ranging from DN 100/100–DN 250/250. The accumulated amount of particles in the fittings was defined as J and introduced into the existing turbidity model PODDS (Prediction of Discolouration in Distribution Systems) proposed by Boxall et al. (2001), which describes the erosion of particles leading to discoloration events in drinking water networks, viz. sections, of straight pipes. It does not interpret the mobilization of particles in pipe fittings, however, which have been considered in this article. T-pieces were the object of this study and depending on the diameter or daily flow velocity, the coefficient J varied from 1.16 to 8.02.

scholarly journals Sphingomonas paucimobilis as a biofilm producer

2012 ◽  
Vol 64 (4) ◽  
pp. 1327-1331 ◽  
Author(s):  
Vera Gusman ◽  
Deana Medic ◽  
Zora Jelesic ◽  
Mira Mihajlovic-Ukropina
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Sphingomonas Paucimobilis ◽  
Drinking Water Distribution Systems ◽  
Modified Method ◽  
Drinking Water Distribution ◽  
Vitek 2 ◽  
First Time

The aim of this study was, for the first time in our country, to identify the capability of isolates of Sphingomonas paucimobilis to form a biofilm. In the 3-month period from January 1st to March 31st 2010, a total of 2630 samples of drinking water were microbiologically examined in the Institute of Public Health of Vojvodina, Serbia. From all examined samples of drinking water, non-fermentative Gram-negative oxidase positive bacilli were identified in 113 samples (4.30%). The bacteria isolates were identified as Sphingomonas paucimobilis (4 isolates), based on analysis by the automated VITEK 2 Compact system; biofilm formation was examined according to the modified method of Stepanovic et al. (2000). All 4 Sphingomonas paucimobilis strains tested showed a strong biofilm-producing ability. Considering the potential pathogenic features of Sphingomonas paucimobilis, the presence of these strains in drinking water distribution systems is not desirable. Therefore, adequate biofilm degradation and management of drinking-water distribution networks that will guarantee microbiologically safe drinking water is recommended.

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