scholarly journals Twenty years of asset management research for Dutch drinking water utilities

2020 ◽  
Vol 20 (8) ◽  
pp. 2941-2950
Author(s):  
R. Beuken ◽  
J. Eijkman ◽  
D. Savic ◽  
A. Hummelen ◽  
M. Blokker
Keyword(s):  
Drinking Water ◽  
Asset Management ◽  
Expert Knowledge ◽  
Focal Point ◽  
Distribution Networks ◽  
Management Research ◽  
Close Collaboration ◽  
Research Questions ◽  
Water Companies ◽  
Five Phases

Abstract This paper gives an overview of the asset management landscape on drinking water in the Netherlands and twenty years of research on this topic executed by KWR in close collaboration with water companies. A description is given of research questions and the international developments in the field of asset management. This is followed by the developments on asset management at the Dutch water company Evides. Twenty years of asset management research at KWR is presented in five phases, showing a transition from the question of how can the concepts of asset management help to better plan the replacement of distribution networks, towards integrated decision making on the asset system as a whole. A focal point for research could be how research can contribute to creating value for water companies. More formal information and improved modelling will continue to play a central role; however, attention is required for making use of expert knowledge, scenario building, data quality and the integration of information of technical, financial and societal origin.

The effects of traffic loads on drinking water main failure frequencies in the Netherlands

2016 ◽  
Vol 11 (3) ◽  
pp. 524-530
Author(s):  
A. Moerman ◽  
B. A. Wols ◽  
R. Diemel
Keyword(s):  
Drinking Water ◽  
Asset Management ◽  
Pipe Material ◽  
Regression Analyses ◽  
Pipe Failure ◽  
Water Pipes ◽  
Traffic Loads ◽  
Diameter Pipe ◽  
Water Companies ◽  
External Loads

Understanding pipe failure is essential for effective asset management. Buried drinking water pipes are exposed to several types of external loads, e.g. soil weight, loads due to soil settling differences and traffic loads. The hypothesis that traffic loads positively affects the number of failures was statistically tested. For three out of four studied water companies significant higher failure frequencies than average were found at road crossings. Frequencies equal to average were found for pipes which are installed under other road sections. Frequencies higher than average–but not statistically significant–were found around speed bumps. The results of the multiple regression analyses show that the overall contribution of the parameter ‘road classification’ to pipe failure is small compared to the influence of pipe diameter, pipe material and year of installation.

Risk communication of hazardous processes associated with drinking water quality - a mental models approach to customer perception, part 1 - a methodology

1999 ◽  
Vol 39 (10-11) ◽  
pp. 183-188 ◽  
Author(s):  
A. J. Owen ◽  
J. S. Colbourne ◽  
C. R. I. Clayton ◽  
C. Fife-Schaw
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Risk Communication ◽  
Mental Models ◽  
Expert Knowledge ◽  
Drinking Water Quality ◽  
Water Industry ◽  
Customer Perception ◽  
Quality Perceptions ◽  
Water Companies

This paper describes a new method of measuring drinking water quality perceptions. Expert knowledge was captured and developed into a model which characterises the potentially hazardous processes inherent in the supply of drinking water. The methodology is based on the psychological framework of “mental modelling” and compares differences in knowledge between water industry experts and lay people. Qualitative studies revealed striking differences between the two groups. These findings are being used to evaluate and improve communications between water companies and their customers about the risks associated with drinking water.

Improving water age estimation in a drinking water distribution network by field study and digital modeling

2021 ◽  
Author(s):  
Jon Kristian Rakstang ◽  
Michael B. Waak ◽  
Marius M. Rokstad ◽  
Cynthia Hallé
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Network Model ◽  
Age Estimation ◽  
Water Distribution ◽  
Distribution Network ◽  
Distribution Networks ◽  
Plate Count ◽  
Water Age ◽  
Drinking Water Distribution

<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>

Shadowing school principals: what do we learn?

2017 ◽  
Vol 47 (1) ◽  
pp. 91-109 ◽  
Author(s):  
Pierre Tulowitzki
Keyword(s):  
School Leadership ◽  
School Principals ◽  
Business Management ◽  
Management Research ◽  
Research Questions ◽  
Leadership Research

While shadowing as a method has been analysed and discussed, these discussions have often been focused on (business) management research as opposed to school leadership research. Additionally, little attention has so far been paid to the parameters of shadowing. Without knowledge of these matters, the validity, merits and difficulties of shadowing and data collected through shadowing are impossible to assess. This contribution aims at tackling these issues. First, it attempts to offer an overview of shadowing. Next, studies on school principals making use of shadowing are analysed, guided by the following research questions: What are the aims of the studies? How is shadowing defined by the author(s)? What are the parameters of the shadowing activities (duration, observers, observed persons)? What are the categories of observation? In conjunction with what other – if any – methods is shadowing used? What – if any – merits or pitfalls of shadowing are discussed? Finally, implications of the current use of shadowing are discussed and suggestions are offered to address desiderata uncovered during the analysis as well as to further develop the method.

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.

scholarly journals Technical note: Problem specific variators in a genetic algorithm for the optimization of drinking water networks

2018 ◽  
Author(s):  
Karel van Laarhoven ◽  
Ina Vertommen ◽  
Peter van Thienen
Keyword(s):  
Drinking Water ◽  
Real World ◽  
Water Distribution ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Technical Note ◽  
Practical Implementation ◽  
Utility Level ◽  
Water Utility ◽  
Drinking Water Distribution

Abstract. Genetic algorithms can be a powerful tool for the automated design of optimal drinking water distribution networks. Fast convergence of such algorithms is a crucial factor for successful practical implementation at the drinking water utility level. In this technical note, we therefore investigate the performance of a suite of genetic variators that was tailored to the optimisation of a least-cost network design. Different combinations of the variators are tested in terms of convergence rate and the robustness of the results during optimisation of the real world drinking water distribution network of Sittard, the Netherlands. The variator configurations that reproducibly reach the furthest convergence after 105 function evaluations are reported. In the future these may aid in dealing with the computational challenges of optimizing real world networks.

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