Francisco Arregui

Integrated Water Meter Management

Water meters are the cornerstone of commercial systems for water utilities throughout the world; revenue is directly derived from the, figures provided by meters. Despite this, little attention has been paid, in terms of selection, replacement period and return on investment, to the management and optimization of water meters.nnIntegrated Water Meter Management is a comprehensive reference for engineers and managers alike, providing: nnIntegrated Water Meter Management is an invaluable resource for those involved in urban water management, including water utility managers, engineering technical staff, operations and maintenance specialists, meter-reading personnel and scientific researchers in this discipline.nnContents nnThis title belongs to Water Research Foundation Report Series nnISBN: 9781843390343 (Print)nnISBN: 9781780402253 (eBook)

Understanding Air Release through Air Valves

This research has been possible thanks to the European Community Programme Access to Major Research Infrastructure under the Fifth Framework Growth Programme (Contract No. GIRT-CT-2002-05069).

Graphical Method to Calculate the Optimum Replacement Period for Water Meters

Calculating the optimum replacement period of meters has always been a major concern for water utility managers. Its determination is time-consuming and requires multiple calculations. This note presents a graphical method to obtain, in a simple but accurate manner, the optimum replacement period of installed meters. For this purpose, a chart has been produced, in which the most influencing variables are considered. These variables include the degradation rate of the weighted error of the meters, the selling price of water, the acquisition and installation cost of the meters, the volume consumed by the users and the discount rate. The chart also allows for a quick sensitivity analysis of different options. For example, by plotting straight lines it is possible to determine by how much the optimum replacement frequency of a meter would change if it degrades at a different rate than expected or if the selling price of water increases.

Nine steps towards a better water meter management.

The paper provides a comprehensive perspective of the critical aspects to be taken into account when planning the long-term management of water meters in a utility. In order to facilitate their quick understanding and practical implementation, they have been structured into nine steps. Ranging from an initial audit up to the final periodic meter replacement planning, these steps cover three aspects of the problem - field work, laboratory work and management tasks; and each one is developed in detail paying attention to the particular data needed and noting the practical outcome it will yield.

Quantifying measuring errors of new residential water meters considering different customer consumption patterns

Water meter measuring errors vary depending on the water flow rate. The difference between water actually consumed and registered by a meter will differ depending on how water consumption is distributed by flow rates. Published studies assessing the performance of new residential meters have only analysed the error curves of the meters – without calculating the influence that consumption patterns have on their field performance. In most cases, research has been limited to analysing compliance with published standards. This work presents an evaluation of the actual commercial losses to be expected considering the consumption characteristic of domestic users. Several types of residential meters have been tested and the error curves obtained have been combined with measured consumption patterns of domestic users. As a result, this paper provides information about the order of magnitude of the initial measuring error as a function of the residential meter model and user characteristics.

Discussion of “Simulating Nonresidential Water Demand with a Stochastic End-Use Model” by E. J. M. Blokker, E. J. Pieterse-Quirijns, J. H. G. Vreeburg, and J. C. van Dijk

The paper under discussion is one of the few published works related to the stochastic modeling of nonresidential water demand. The model proposed by the authors is of great interest and will help in improving the knowledge of consumption patterns associated with different types of uses. It will also serve as an excellent starting point for future developments in water-demand modeling. The discussers acknowledge that developing such a model is extremely complex due to the large heterogeneity of facilities and equipment and, in general, the diversity in users’ consumption patterns. Therefore, the discussers want to extend their most sincere congratulations to the authors for their study. However, based on the discussers’ experience, it is appropriate to make some clarifications regarding the modeling of water demand in hotels that will contribute to improving future developments in this field. For this purpose, actual consumption data obtained in different measurement campaigns for various hotel rooms is presented. In total, approximately 1,500 full days of measurements were analyzed. Water consumption was recorded with a volume resolution as low as 0.1 L, which allowed for a meticulous data analysis. By means of a specific software tool, the discussers were able to discriminate among the different uses of water in hotel rooms and to classify them into various microcomponents (toilet cistern, shower, and tap). This analysis was possible thanks to the high resolution measurements taken for hot and cold water consumption (Cobacho et al. 2005). As a result, the individual characteristics of the various end-uses present in a hotel room were obtained. The conclusions of this study are used to assess some of the assumptions made by the authors in their work.

Assessing sustainability of rural gravity-fed water schemes on Idjwi Island, D.R. Congo

ABSTRACT To assess the sustainability of rural gravity-fed water schemes on Idjwi Island, the association between four hypothesized drivers of sustainability – perceived sense of ownership, willingness to pay for maintenance, trust in the water committee, and household involvement in the project – and service reliability, the main outcome variable, was analyzed. Primary data were gathered through in-person surveys of 1253 user households. The results provide two significant insights. First, during the 5–10 years after implementation, in the presence of an external intervention, a lower perceived sense of ownership for the water system was associated with higher service reliability. This stands in contrast with much of the existing literature, which outlines a consistent positive association between sense of ownership and sustainability of rural water systems. Second, despite 77% of beneficiaries stating that they were willing to pay for maintenance service, such contributions were not forthcoming, due to lack of trust in the water committee. In this scenario, almost 42% of the water points are reported as non-functional, 5–10 years after completion.

Hydraulic transient in residential buildings with a direct pump connection

This paper consists of an experimental and numerical study into transient behaviour in a residential building. The analysed effects occur by centrifugal pumps when they start with a direct supply (fixed-speed pumps are connected to the service pipe without an atmospheric tank). Direct supply increases the transient effect and places higher demands on the water main. The properties of such an installation were analysed using a hydraulic model in order to detect the most unfavourable scenario. The results were compared to experimental data. Basic hydraulics demonstrates that a pressure drop occurs during the start-up. The magnitude mainly depends on the pump capacity. But, numerical and field results show that other variables related to service pipe design could also negatively affect the pressure surge. The study provides water utilities with information about the influence of the different variables on pressure surge magnitude and basic design criteria to minimize these effects.