Investigation of factors affecting rural drinking water consumption using intelligent hybrid models

Identifying the factors affecting drinking water consumption is essential to the rational management of water resources and effective environment protection. In this study, the effects of the factors on rural drinking water demand were studied using the adaptive neuro-fuzzy inference system (ANFIS) and hybrid models, such as the ANFIS-genetic algorithm (GA), ANFIS-particle swarm optimization (PSO), and support vector machine (SVM)-simulated annealing (SA). The rural areas of Hamadan Province in Iran were selected for the case study. Five drinking water consumption factors were selected for the assessment according to the literature, data availability, and the characteristics of the study area (such as precipitation, relative humidity, temperature, the number of subscribers, and water price). The results showed that the standard errors of ANFIS, ANFIS-GA, ANFIS-PSO, and SVM-SA were 0.669, 0.619, 0.705, and 0.578, respectively. Therefore, the hybrid model SVM-SA outperformed other models. The sensitivity analysis showed that of the parameters affecting drinking water consumption, the number of subscribers significantly affected the water consumption rate, while the average temperature was the least significant factor. Water price was a factor that could be easily controlled, but it was always one of the least effective parameters due to the low water fee.

Water System Condition and Asset Replacement Prioritization

The goal of asset management is to identify and track the maintenance and replacement of assets that have reached their useful life. For that reason, gathering data and collecting information is a critical step when developing an asset management plan. Such data gathering includes physical and operational properties of the assets as well as collecting and tracking important events during the lifespan of the asset (i.e., pipe breaks, replacement year, maintenance performed, etc.). Critical factors in the asset management plan may be overlooked when there is no data or poor quality data. However, many utilities lack the resources for examining buried infrastructure and lack good quality work order data, so other methods of data collection are needed. The concept for this paper was to develop a means to acquire data on the assets for a condition assessment to identify pipes that were most likely to break and those with the highest consequences for same. Three utilities were used as examples. It was found that for buried infrastructure, much more information was known than anticipated but the actual predictions relied on only a few factors related to pipe type. However, there is a need to track the consequences, in this case breaks, which would indicate a failure. The latter would be useful for predicting future maintenance needs and the most at-risk assets, but is often missing in utility systems as many utilities do not adequately track breaks sufficiently. In this case two utilities were analyzed and predication on a third was developed.

Root distribution and influencing factors of dry-sowing and wet-growing cotton plants under different water conditions

To study the effect of soil water and salt environment factors on the root growth of cotton under different moisture control,three different emergence water volumes(60,105,and 150 m^(3)/hm^(2)),two different frequencies(high frequency and low frequency)and one double film cover winter irrigation control treatment(CK:2250 m^(3)/hm^(2))were set up to analyze the spatial distribution patterns of soil water and salt environment and root density in dry sown and wet emerged cotton fields under diffe-rent moisture control conditions.The results show that the soil water content and water infiltration range gradually become larger with the increase of seedling water quantity,and the larger the seedling water quantity,the higher the soil water content.With the same seedling water quantity,the soil water content of the high-frequency(HF)treatment becomes obviously larger.The soil conductivity of each treatment tends to decrease gradually with the increase of seedling water and drip frequency,among which the distribution of soil conductivity of S6 treatment is closest to that of CK.With the increase in soil depth,the soil conductivity tends to increase first and then decrease.Compared with the low-frequency(LF)treatment,the high-frequency treatment shows a significantly deeper soil salt accumulation layer.The root length density(RLD)of cotton gradually increases with the amount of seedling water and the frequency of dripping.The soil layer of root distribution gradually deepens with the amount of seedling water in the vertical direction,and the RLD value in the horizontal direction is significantly greater in the mulched area than that in the bare area between films.This research can serve as a solid scientific foundation for the use of dry sowing and wet emergence techniques in cotton fields in southern Xinjiang.

Application of Dynamic Programming Method in Optimization of Water Distribution Pipe Network

With a water-supply network by dynamic programming. The minimal as an example, the network was optimized annual discounted costs were taken as an objective function and node pressure etc. as constraint conditions. The alternative pipe diameters were optimized as per enumeration method and the group allowing objective function with the least values would be the optimized one. It is proved the optimized pipe network reduced by 11.49% in terms of cost and the optimized ben- efits proved much significant.

STUDY ON OPTIMAL CONTROL OF MUNICIPAL WATER DISTRIBUTION NETWORK

A systematic investigation is made on the problems which are related to the optimal control of the municipal water distribution network.A mathematical model of forecasting the water short term demand is proposed using the time series trigonometric function analysis method;the service discharge based macroscopic model of network performance is established using the network structuring method;a relatively satisfactory mathematical model for the optimal control of water distribution network is put forward in view of security and economy,and solved by the constrained mixed discrete variable complex arithmetic.The model is applied in many examples and the results are satisfactory.

Use of two-stage dough mixing process in improving water distribution of dough and qualities of bread made from wheat–potato flour

The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour(PF) and wheat flour at a ratio of 1:1(w/w). The final dough was first prepared from wheat flour before being added with PF. The effects of the method on enhancing the dough qualities were verified, and the distribution of water in gluten-gelatinized starch matrix of the doughs was investigated. We observed that the bread qualities were improved, as reflected by the increase of specific volume from 2.26 to 2.96 m L g^–1 and the decrease of crumb hardness from 417.93 to 255.57 g. The results from rheofermentometric measurements showed that the dough mixed using the developed mixing method had higher maximum dough height value, time of dough porosity appearance, and gas retention coefficient, as well as enhanced gluten matrix formation compared to that mixed by the traditional mixing method. The results from low-field nuclear magnetic resonance confirmed that the competitive water absorption between gluten and gelatinized starch could restrict the formation of gluten network in the dough mixed using the traditional mixing process. Using the novel mixing method, gluten could be sufficiently hydrated in stage 1, which could then weaken the competitive water absorption caused by gelatinized starch in stage 2;this could also be indicated by the greater mobility of proton in PF and better development of gluten network during mixing.

Modeling of residual chlorine in water distribution system

Water quality within water distribution system may vary with both location and time. Water quality models are used to predict the spatial and temporal variation of water quality throughout water system. A model of residual chlorine decay in water pipe has been developed, given the consumption of chlorine in reactions with chemicals in bulk water, bio films on pipe wall, in corrosion process, and the mass transport of chlorine from bulk water to pipe wall. Analytical methods of the flow path from water sources to the observed point and the water age of every observed node were proposed. Model is used to predict the decay of residual chlorine in an actual distribution system. Good agreement between calculated and measured values was obtained.

Online location of seismic damage to a water distribution system

As one of the most important urban lifeline systems,a water distribution system can be damaged under a strong earthquake,and the damage cannot easily be located,especially immediately after the event.This often causes tremendous difficulties to post-earthquake emergency response and recovery activities.This paper proposes a methodology to locate seismic damage to a water distribution system by monitoring water head online at some nodes in the water distribution system.An artificial neural network-based inverse analysis method is developed to estimate the water head variations at all nodes that are not monitored based on the water head variations at the nodes that are monitored.The methodology provides a quick,effective,and practical way to locate seismic damage to a water distribution system.

A Distributed Monthly Water Balance Model for Analyzing Impacts of Land Cover Change on Flow Regimes

The Miyun Reservoir is the most important water source for Beijing Municipality, the capital of China with a population of more than 12 million. In recent decades, the inflow to the reservoir has shown a decreasing trend, which has seriously threatened water use in Beijing. In order to analyze the influents of land use and cover change (LUCC) upon inflow to Miyun Reservoir, terrain and land use information from remote sensing were utilized with a revised evapotranspiration estimation formula; a water loss model under conditions of human impacts was introduced; and a distributed monthly water balance model was established and applied to the Chaobai River Basin controlled by the Miyun Reservoir. The model simulation suggested that not only the impact of land cover change on evapotranspiration, but also the extra water loss caused by human activities, such as the water and soil conservation development projects should be considered. Although these development projects were of great benefit to human and ecological protection, they could reallocate water resources in time and space, and in a sense thereby influence the stream flow.

Iron stability in drinking water distribution systems in a city of China

A field study on the estimation and analysis of iron stability in drinking water distribution system was carried out in a city of China. The stability of iron ion was estimated by pC-pH figure. It was found that iron ion was unstable, with a high Fe （OH）3 precipitation tendency and obvious increase in turbidity. The outer layer of the corrosion scale was compact, while the inner core was porous. The main composition of the scale was iron, and the possible compound constitutes of the outer scale were α-FeOH, γ-FeOOH, α-Fe2O3, γ-F2O3, FeCl3, while the inner were Fe3O4, FeCl2, FeCO3. According to the characteristics of the corrosion scale, it was thought that the main reason for iron instability was iron release from corrosion scale. Many factors such as pipe materials, dissolved oxygen and chlorine residual affect iron release. Generally, higher iron release occurred with lower dissolved oxygen or chlorine residual concentration, while lower iron release occurred with higher dissolved oxygen or chlorine residual concentration. The reason was considered that the passivated out layer of scale of ferric oxide was broken down by reductive reaction in a condition of low oxidants concentration, which would result more rapid corrosion of the nine and red water phenomenon.

Optimal operation of water distribution networks under local pipe failures

The optimal operation of water distribution networks under local pipe failures, such as water main breaks, was proposed. Based on a hydraulic analysis and a simulation of water distribution networks, a macroscopic model for a network under a local pipe failure was established by the statistical regression. After the operation objectives under a local pipe failure were determined, the optimal operation model was developed and solved by the genetic algorithm. The program was developed and examined by a city distribution network. The optimal operation alternative shows that the electricity cost is saved approximately 11%, the income of the water corporation is increased approximately 5%, and the pressure in the water distribution network is distributed evenly to ensure the network safe operation. Therefore, the proposed method for optimal operation under local pipe failure is feasible and cost-effective.

Identification of contamination source in water distribution network based on consumer complaints

A new methodology was proposed for contamination source identification using information provided by consumer complaints from a probabilistic view.Due to the high uncertainties of information derived from users,the objective of the proposed methodology doesn't aim to capture a unique solution,but to minimize the number of possible contamination sources.In the proposed methodology,all the possible pollution nodes are identified through the CSA methodology firstly.And then based on the principle of total probability formula,the probability of each possible contamination node is obtained through a series of calculation.According to magnitude of the probability,the number of possible pollution nodes is minimized.The effectiveness and feasibility of the methodology is demonstrated through an application to a real case of ZJ City.Four scenarios were designed to investigate the influence of different uncertainties on the results in this case.The results show that pollutant concentration,injection duration,the number of consumer complaints nodes used for calculation and the prior probability with which consumers would complaint have no particular effect on the identification of contamination source.Three nodes were selected as the most possible pollution sources in water pipe network of ZJ City which includes more than 3 000 nodes.The results show the potential of the proposed method to identify contamination source through consumer complaints.

Seismic Reliability and Rehabilitation Decision of Water Distribution System

In order to evaluate the seismic reliability of water distribution system and make rehabilitation decisions correspondingly, it is necessary to assess pipelines damage states and conduct functional analysis based on pipe leakage model. When an earthquake occurred, the water distribution system kept serving with leakage. By adding a virtual node at the centre of the pipeline with leakage, an efficient approach to pressure-driven analysis was developed for simulating a variety of low relative scenarios, and a hydraulic leakage model was also built to perform hydraulic analysis of the water supply network with seismic damage. Then the mean-first-order-second-moment method was used to analyse the seismic serviceability of the water distribution system. According to the assessment analysis, pipes that were destroyed or in heavy leakage were isolated and repaired emergently, which improved the water supply capability of the network and would constitute the basis for enhancing seismic reliability of the system. The proposed approach to seismic reliability and rehabilitation decision analysis on water distribution system is demonstrated effective through a case study.

Water Distribution and Removal along the Flow Channel in Proton Exchange Membrane Fuel Cells

Distribution expressions of total gas pressure and partial water vapor pressure along the channel direction were established based on lumped model by analyzing pressure loss in the channel and gas diffusion in the layer. The mechanism of droplet formation in the flow channel was also analyzed. Effects of the relative humidity, working temperature and stoichiometry on liquid water formation were discussed in detail. Moreover, the force equilibrium equation of the droplet in the flow channel was deduced, and the critical flow velocity for the water droplet removal was also addressed. The experimental results show that the threshold position of the liquid droplet is far from the inlet with the increase of temperature, and it decreases with the increase of the inlet total pressure. The critical flow velocity decreases with the increase of the radius and the working pressure.

Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu Lake in Taihu Basin

On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtz,e River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and water quality conjunctive dispatching ＇decisi＂ofi-makifig support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the -integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

Seismic reliability analysis of urban water distribution network

An approach to analyze the seismic reliability of water distribution networks by combining a hydraulic analysis with a first-order reliability method （FORM）, is proposed in this paper. The hydraulic analysis method for normal conditions is modified to accommodate the special conditions necessary to perform a seismic hydraulic analysis. In order to calculate the leakage area and leaking flow of the pipelines in the hydraulic analysis method, a new leakage model established from the seismic response analysis of buried pipelines is presented. To validate the proposed approach, a network with 17 nodes and 24 pipelines is investigated in detail. The approach is also applied to an actual project consisting of 463 nodes and 767 pipelines. The results show that the proposed approach achieves satisfactory results in analyzing the seismic reliability of large-scale water distribution networks.

Partitioning of Water Distribution Network into District Metered Areas Using Existing Valves

Water distribution network(WDN)leakage management has received increased attention in recent years.One of the most successful leakage-control strategies is to divide the network into District Metered Areas(DMAs).As a multi-staged technique,the generation of DMAs is a difficult task in design and implementation(i.e.,clustering,sectorization,and performance evaluation).Previous studies on DMAs implementation did not consider the potential use of existing valves in achieving the objective.In this work,a methodology is proposed for detecting clusters and reducing the cost of additional valves and DMA sectorization by considering existing valves as much as possible.The procedure of DMAs identification has been divided into three stages,i.e.,a)clusters identification;b)sectorization or boundaries optimization and c)performance evaluation of the partitioned network.The proposed methodology is evaluated on a simple network and a real-world water network with the findings provided and compared to the DMAs,established for a raw water network with no existing valves.It is found that there is an adequate difference in cost of strategy implementation in both the cases for the network under consideration and the existing valve system achieved better network performance in terms of resilience index.

Leak Detection in Water Distribution Systems Using Bayesian Theory and Fisher’s Law

A leak detection method based on Bayesian theory and Fisher’s law was developed for water distribution systems. A hydraulic model was associated with the parameters of leaks (location, extent). The randomness of parameter values was quantified by probability density function and updated by Bayesian theory. Values of the parameters were estimated based on Fisher’s law. The amount of leaks was estimated by back propagation neural network. Based on flow characteristics in water distribution systems, the location of leaks can be estimated. The effectiveness of the proposed method was illustrated by simulated leak data of node pressure head and flow rate of pipelines in a test pipe network, and the leaks were spotted accurately and renovated on time.

Partial Least Squares Regression Model to Predict Water Quality in Urban Water Distribution Systems

The water distribution system of one residential district in Tianjin is taken as an example to analyze the changes of water quality.Partial least squares(PLS) regression model,in which the turbidity and Fe are regarded as control objectives,is used to establish the statistical model.The experimental results indicate that the PLS regression model has good predicted results of water quality compared with the monitored data.The percentages of absolute relative error(below 15%,20%,30%) are 44.4%,66.7%,100%(turbidity) and 33.3%,44.4%,77.8%(Fe) on the 4th sampling point;77.8%,88.9%,88.9%(turbidity) and 44.4%,55.6%,66.7%(Fe) on the 5th sampling point.

Variability of micropollutants and microorganisms in water distribution system

The variation of water quality in water distribution system was investigated with assimilable organic carbon (AOC)and trihalomethanes(THMs) used as assessment indexes. Bacterium was identified in water distribution. The result showed that there were pathogenic parasites in water distribution system. The variation of AOC is related to chlorine residual and bacterium activity, and AOC concentration decreased first and then increased with the extension of water distribution system. The formation of THMs was related to the consumption of chlorine inside the distribution system, and THMs concentration increased with the extension of water pipe line.