Design Of Water Supply Systems Research Articles

Factorial Analysis of Trihalomethanes Formation in Drinking Water

Disinfection of drinking water reduces pathogenic infection, but may pose risks to human health through the formation of disinfection byproducts. The effects of different factors on the formation of trihalomethanes were investigated using a statistically designed experimental program, and a predictive model for trihalomethanes formation was developed. Synthetic water samples with different factor levels were produced, and trihalomethanes concentrations were measured. A replicated fractional factorial design with center points was performed, and significant factors were identified through statistical analysis. A second-order trihalomethanes formation model was developed from 92 experiments, and the statistical adequacy was assessed through appropriate diagnostics. This model was validated using additional data from the Drinking Water Surveillance Program database and was applied to the Smiths Falls water supply system in Ontario, Canada. The model predictions were correlated strongly to the measured trihalomethanes, with correlations of 0.95 and 0.91, respectively. The resulting model can assist in analyzing risk-cost tradeoffs in the design and operation of water supply systems.

Improved performance of PSO with self-adaptive parameters for computing the optimal design of Water Supply Systems

This paper deals with a new variant of Particle Swarm Optimization (PSO) in which no a priori parameter tuning is necessary. PSO, as an efficient and powerful problem-solving technique, has been widely used, but, as in other Evolutionary Algorithms (EA), appropriate adjustment of its parameters is cumbersome and usually requires a lot of time, effort and luck. Thus, a self-adaptive framework is proposed to improve the robustness of the PSO. In this paper, within a framework that also includes other variants previously introduced by the authors, the algorithm’s parameters are co-evolved with the particles. Its performance results show that the use of this self-adaptive feature averages out the performance of standard PSO and other EA applied to the same problems, namely the design of Water Supply Systems (WSS), while avoiding the process of localizing and fine-tuning suitable parameters values, when using two benchmarking problems presented in the literature, namely the Hanoi Water Supply System and the New York Tunnel Water Supply System. The results provided in the case of a real-world problem demonstrate the scalability of the proposed variant to the realistic water distribution design problems, which are much larger.

Design of Ethernet-Based Constant Pressure Water Supply and Remote Monitoring System

To realize the constant pressure water supply, a frequency converter is used to control the periodic duty of three pumps in this paper. Then, the communication between host computer and field control equipment is studied and realized by using industry Ethernet Graphical control interface, and remote monitoring is realized.

Embedding sustainability in the design of water supply and drainage systems for buildings

In addressing sustainability issues for the built environment, focus is often directed towards minimising energy consumption and material use. Often forgotten however, is the potential for the integration of sustainable solutions when designing water and waste management systems for buildings. The fundamental functions of such systems are clearly recognised, but traditional design principles often constrain opportunities for performance enhancement and for water and pipework economies. To an extent, this is unsurprising, given the basic premise that steady-state analysis of flows underpins many of the codes and guidelines used worldwide. However, advances in simulation methods mean that system performance resulting from the use of new techniques and from the integration of innovative and more sustainable design approaches can now be fully assessed. This paper provides an overview of the water supply and drainage systems for buildings whose performance has been assessed through the development, at Heriot–Watt University, of a suite of numerical simulation models. These models accurately predict, using appropriate forms of the St. Venant equations, the pressure and flow regime within such systems by applying the Method of Characteristics finite difference technique. The paper provides three different examples of application, where the focus of each is on embedding sustainability in design.

Reliable water supply system design under uncertainty

Given the natural variability and uncertainties in long-term predictions, reliability is a critical design factor for water supply systems. However, the large scale of the problem and the correlated nature of the involved uncertainties result in models that are often intractable. In this paper, we consider a municipal water supply system over a 15-year planning period with initial infrastructure and possibility of construction and expansion during the first and sixth year on the planning horizon. Correlated uncertainties in water demand and supply are applied on the form of the robust optimization approach of Bertsimas and Sim to design a reliable water supply system. Robust optimization aims to find a solution that remains feasible under data uncertainty. Such a system can be too conservative and costly. In the Bertsimas and Sim approach, it is possible to vary the degree of conservatism to allow for a decision maker to understand the tradeoff between system reliability and economic feasibility/cost. The degree of conservatism is incorporated in the probability bound for constraint violation. As a result, the total cost increases as the degree of conservatism (and reliability) is increased. In the water supply system application, a tradeoff exists between the level of conservatism and imported water purchase. It was found that the robust optimization approach addresses parameter uncertainty without excessively affecting the system. While we applied our methodology to hypothetical conditions, extensions to real-world systems with similar structure are straightforward. Therefore, our study shows that this approach is a useful tool in water supply system design that prevents system failure at a certain level of risk.

Design of multiquality irrigation water supply systems using the Q–C feasibility domain concept: II. QCFD model and applications

AbstractThe world shortage in water sources for irrigation indicates a need to exploit poor water quality sources. Traditional design methods of irrigation systems consider primarily the hydraulic aspects. Inclusion of water quality aspects requires new tailored design methods. The method suggested herein is part of a continuous effort taken in that direction. Earlier works paved the way for the presently suggested design model which computes the feasibility domain of water discharge and quality of supply networks. Steady‐state conditions, conservative water quality parameters, instantaneous and complete mixing of water from diverse water quality sources were assumed. The Q–C (chemical transport sub‐problem) was dealt with and the QC feasibility domains of sources for the inner nodes and outlets were computed for every feasible flow pattern in a given network. Feasibility of supply was evaluated by comparing demand (water discharge and quality) values with the supply values computed by the QCFD. Real water supply in a rural community in the Arava desert, Israel, was designed using the QCFD model. Feasibility of various irrigation schedules was tested and a guideline for operation derived. The method, however, needs further improvement. Copyright © 2008 John Wiley & Sons, Ltd.

Design of irrigation water supply systems using the Q–C feasibility domain concept: I. Introduction and theory

AbstractThe Q–C Feasibility Domain (QCFD) was defined and proposed as a tool for design of multiquality irrigation water supply systems. It determines all feasible combinations of water discharge and water quality, and can be represented by a point, a line, or an area in a diagram of water discharge versus solute flow rate (a Q–J diagram). The shape of the QCFD is the result of dilution of two or more flows from sources of different water quality. (assuming conservative substances) Several types of QCFDs were analyzed at sources, inner nodes of a network, and of consumer outlets. The effect of water discharge constraints (due to flow limitations in the network) on the QCFDs was formulated and analyzed. Computation of QCFDs of dilution junctions by vector addition of their inflows was described. The method was extended numerically to nonlinear mixing due to dependence of water salinity. Use of this method enables computation of QCFDs for inner nodes in networks, including dilution junctions. The effect of network topology and flow direction was discussed. Application and demonstration will follow in the next paper in this series. Copyright © 2008 John Wiley & Sons, Ltd.

Particle Swarm Optimization applied to the design of water supply systems

In the past decade, evolutionary methods have been used by various researchers to tackle optimal design problems for water supply systems (WSS). Particle Swarm Optimization (PSO) is one of these evolutionary algorithms which, in spite of the fact that it has primarily been developed for the solution of optimization problems with continuous variables, has been successfully adapted in other contexts to problems with discrete variables. In this work we have applied one of the variants of this algorithm to two case studies: the Hanoi water distribution network and the New York City water supply tunnel system. Both cases occur frequently in the related literature and provide two standard networks for benchmarking studies. This allows us to present a detailed comparison of our new results with those previously obtained by other authors.

Managing urban water supplies in developing countries – Climate change and water scarcity scenarios

Urban areas of developing countries are facing increasing water scarcity and it is possible that this problem may be further aggravated due to rapid changes in the hydro-environment at different scales, like those of climate and land-cover. Due to water scarcity and limitations to the development of new water resources, it is prudent to shift from the traditional ‘supply based management’ to a ‘demand management’ paradigm. Demand management focuses on measures that make better and more efficient use of limited supplies, often at a level significantly below standard service levels. This paper particularly focuses on the intermittent water supplies in the cities of developing countries. Intermittent water supplies need to be adopted due to water scarcity and if not planned properly, results in inequities in water deliveries to consumers and poor levels of service. It is therefore important to recognise these realities when designing and operating such networks.The standard tools available for design of water supply systems often assume a continuous, unlimited supply and the supplied water amount is limited only be the demand, making them unsuitable for designing intermittent supplies that are governed by severely limited water availability. This paper presents details of new guidelines developed for the design and control of intermittent water distribution systems in developing countries. These include a modified network analysis simulation coupled with an optimal design tool. The guidelines are driven by a modified set of design objectives to be met at least cost. These objectives are equity in supply and people driven levels of service (PDLS) expressed in terms of four design parameters namely, duration of the supply; timings of the supply; pressure at the outlet (or flow-rate at outlet); and others such as the type of connection required and the locations of connections (in particular for standpipes). All the four parameters are calculated using methods and techniques that recognise the relationship between outflow at a water connection and the pressure experienced at that connection. The paper presents a case study where it is demonstrated that the new guidelines can provide an equitable and acceptable level of service throughout the design horizon of the project.

Factorial Analysis of Trihalomethanes Formation in Drinking Water

Disinfection of drinking water reduces pathogenic infection, but may pose risks to human health through the formation of disinfection byproducts. The effects of different factors on the formation of trihalomethanes were investigated using a statistically designed experimental program, and a predictive model for trihalomethanes formation was developed. Synthetic water samples with different factor levels were produced, and trihalomethanes concentrations were measured. A replicated fractional factorial design with center points was performed, and significant factors were identified through statistical analysis. A second-order trihalomethanes formation model was developed from 92 experiments, and the statistical adequacy was assessed through appropriate diagnostics. This model was validated using additional data from the Drinking Water Surveillance Program database and was applied to the Smiths Falls water supply system in Ontario, Canada. The model predictions were correlated strongly to the measured trihalomethanes, with correlations of 0.95 and 0.91, respectively. The resulting model can assist in analyzing risk-cost tradeoffs in the design and operation of water supply systems.

Defining Sustainability: New Tools for Water Management

This article discusses new tools to help plan for and incorporate sustainability of water resources into water supply system design and operation. Environmental stewardship is discussed and explained as minimizing the effect of water supply management on downstream ecosystems. The article presents advances in computer modeling that help in balancing changing water demands with improved understanding of environmental needs. Specifically, the article discusses the Stockholm Environment Institute's Water Evaluation and Planning (WEAP) modeling platform and lists the four elements of water supply management that it offers.

Assessment of factors which affect multiple uses of water sources at household level in rural Zimbabwe – A case study of Marondera, Murehwa and Uzumba Maramba Pfungwe districts

Water with all its multiple uses plays a pivotal role in the sustenance of rural livelihoods, especially the poor. As such, the provision of water which go beyond domestic to include water for small-scale productive uses should be encouraged to enhance peoples’ livelihood options by making significant contribution to household income, food security, improved nutrition and health. All these multiple benefits, if combined can assist in the fight against hunger and poverty. This study was conducted in Mashonaland East province, covering Marondera, Murehwa and Uzumba Maramba Pfungwe districts in Zimbabwe for the period December 2005–May 2006 to assess factors which affect multiple uses of water sources at household level. Participatory Rural Appraisal tools such as discussions, observations and interviews were used for data collection. The survey found that people indeed require water for productive purposes apart from domestic uses, which are often given top priority. The study found out that multiple uses of water sources at household level can be affected by segmentation of water services into domestic and productive water supply schemes, technology and system design, water quality and quantity and distance to water sources among other factors. The study recommends that water service providers to be able to provide appropriate, efficient and sustainable services, they should understand and appreciate that people’s water needs are integrated and are part and parcel of their multifaceted livelihood strategies.

Assessing the relevance of intervening parameters on the per capita water consumption rates in Brazilian urban communities

The determination of the per capita water consumption is an essential step in the design of water supply systems. The present paper examines the influence of several variables on the per capita water consumption, based on 96 different towns in the Brazilian state of Minas Gerais. The set of samples was categorised firstly into five different classes and three distinct population intervals and, finally, was presented in overall terms. The paper also attempts to explain the relative influence of the intervening factors for each population range, and presents a multivariate regression model for the per capita water consumption rates for towns with populations ranging from 50,000 to 100,000 inhabitants. For this population range, the significant variables were: (a) percentage of water metering, (b) water tariff, and (c) energy consumption by commercial and industrial activities.

Short‐term municipal water demand forecasting

AbstractWater demand forecasts are needed for the design, operation and management of urban water supply systems. In this study, the relative performance of regression, time series analysis and artificial neural network (ANN) models are investigated for short‐term peak water demand forecasting. The significance of climatic variables (rainfall and maximum air temperature, in addition to past water demand) on water demand management is also investigated.Numerical analysis was performed on data from the city of Ottawa, Ontario, Canada. The existing water supply infrastructure will not be able to meet the demand for projected population growth; thus, a study is needed to determine the effect of peak water demand management on the sizing and staging of facilities for developing an expansion strategy. Three different ANNs and regression models and seven time‐series models have been developed and compared. The ANN models consistently outperformed the regression and time‐series models developed in this study. It has been found that water demand on a weekly basis is more significantly correlated with the rainfall amount than the occurrence of rainfall. Copyright © 2005 John Wiley & Sons, Ltd.

Economic, water quantity and quality impacts from the use of a rainwater tank in the inner city

A dual water supply system (rainwater and mains water) has been installed at an old house in Maryville a inner city suburb of Newcastle in New South Wales, Australia. A design was developed for the installation of a rainwater tank to supply rainwater for toilet, hot water and outdoor uses. The rainwater supply is supplemented with mains water via a trickle top-up system when water levels are low in the tank. An air gap is used for backflow prevention in accordance with Australian standards. The design, construction and performance of the dual water supply system at the Maryville house are examined in this paper. Monitoring of water quality from the rainwater tank and from an instantaneous hot water service at the Maryville house has revealed that the rainwater was acceptable for hot water, toilet and outdoor uses. Rainwater used in the hot water service was compliant with Australian drinking water standards. The cost of rainwater has been found to be $0.30 per kL which is less than the price of mains water in the Lower Hunter region and the commonly assumed cost of $1.00 to $14.00 per kL.

A Study on the Reliability of Fire Water Supply System in High-rise Buildings

This paper puts forward the significance of study for the reliability of fire water supply system in high-rise buildings, as an exploration for the reliability of fire water supply system to attract the attention from experts on this issue. It briefly introduces the reliability model and calculation of the system, and analyses functional application process and probability features of the system. It raises the principles of reliability design and the method of improving reliability to benefit the optimization of fire water supply system design. Moreover, the development of reliability study has been looked ahead in the paper.

A methodology for the design of photovoltaic water supply systems

AbstractPhotovoltaic pumping systems are used nowadays as a valuable alternative to supply water to communities living in remote rural areas. Owing to the seasonal variation and the stochastic behavior of solar radiation, at certain times the supply of water may not be able to meet demand. A study has been made of the relationship between water pumping capacity, reservoir size and water demand, for a given water deficit. As a result, curves of equal water deficit (iso‐deficit lines) can be obtained for various combinations of PV pumping capacity and reservoir size. A methodology to generate those curves is described, using as its main tool the characteristic curve of the system, that is, the relationship between water flow and collected solar radiation. The characteristic curve represents the combined behavior of the water pumping system and the well. The influence of the minimum collected solar radiation level, necessary to start the system's operation (the critical radiation level IC), is also analyzed. Results show that PV pumping systems with different characteristic curves, but with the same critical levels, yield the same set of iso‐deficit lines. This drastically reduces the number of necessary solutions to those corresponding to a few values of IC. Iso‐deficit lines, calculated for the locality of Recife (PE), Brazil, are used to illustrate the sizing procedure PV water supply systems. Copyright © 2001 John Wiley & Sons, Ltd.

Evaluation methods for the design of adaptive water supply systems in urban environments

The issue of sustainable modes of development are not restricted to those concerning environmental protection or pollution control/minimisation. In generic terms, sustainable systems are those which can be adapted to changing circumstances. Given the essential nature of utilities there is a clear need to plan and manage their technologies in a sustainable manner. This paper offers an initial theoretical structure for designing and managing adaptive technological infrastructures for utilities in generic terms and suggests how such a framework may apply to water supply systems. In particular, the development of new water recycling technologies and the emergence of ‘complex system’ modelling techniques provide opportunities for the design of water supply systems which are adaptive to changes in the urban social and physical environment in which they are embedded.

Evaluation methods for the design of adaptive water supply systems in urban environments

The issue of sustainable modes of development are not restricted to those concerning environmental protection or pollution control/minimisation. In generic terms, sustainable systems are those which can be adapted to changing circumstances. Given the essential nature of utilities there is a clear need to plan and manage their technologies in a sustainable manner. This paper offers an initial theoretical structure for designing and managing adaptive technological infrastructures for utilities in generic terms and suggests how such a framework may apply to water supply systems. In particular, the development of new water recycling technologies and the emergence of ‘complex system’ modelling techniques provide opportunities for the design of water supply systems which are adaptive to changes in the urban social and physical environment in which they are embedded.

給水・給湯負荷の計測と時系列解析を用いた時間負荷変動の予測 : 集合住宅における給水負荷変動の予測に関する研究

In these days, design of water supply system need high pressure water works on quality management for receiving tank in building. So it has been necessary for building management to forecast the change of water consumption in building. But, there are very few studies considering life cycle cost for water supply system in buildings. In this paper, at first, the authors have investigated in detail for the loads of cold and hot water supply in apartment houses by using a new technics of measurment, and analyzed the demand fluctuations by specific use considering time span. Finally, time series models were identified and estimated, and then according to time series analysis, the hourly load profile were forecasted in each day.