Doo Yong Choi

Pressure measurements with valve-induced transient flow in water pipelines

Pressure measurements provide valuable insights for managing water supply systems by tracking time-dependent hydraulic transients. In this study, we report on two pressure-monitoring issues – sampling location and sampling interval – by analyzing a valve-induced transient event that was not recorded in the 1-min timestamp pressure generated by the existing supervisory control and data acquisition (SCADA) system of a real water transmission line in the southern part of Korea. Field measurement data show that the measured pressure magnitude is influenced by the sampling location, which depends on pipe connectivity and distance from automatic control valve, and by the sampling interval, which is sensitive to network size for wave propagation. Based on the findings of the field experiments, a pressure-measurement method is proposed by employing numerical transient simulation and spectral analysis of pressure waves.

In-Depth Investigation of Statistical and Physicochemical Properties on the Field Study of the Intermittent Filling of Large Water Tanks

Large-demand customers, generally high-density dwellings and buildings, have dedicated ground or elevated water tanks to consistently supply drinking water to residents. Online field measurement for Nonsan-2 district meter area demonstrated that intermittent replenishment from large-demand customers could disrupt the normal operation of a water distribution system by taking large quantities of water in short times when filling the tanks from distribution mains. Based on the previous results of field measurement for hydraulic and water quality parameters, statistical analysis is performed for measured data in terms of autocorrelation, power spectral density, and cross-correlation. The statistical results show that the intermittent filling interval of 6.7 h and diurnal demand pattern of 23.3 h are detected through autocorrelation analyses, the similarities of the flow-pressure and the turbidity-particle count data are confirmed as a function of frequency through power spectral density analyses, and a strong cross-correlation is observed in the flow-pressure and turbidity-particle count analyses. In addition, physicochemical results show that the intermittent refill of storage tank from large-demand customers induces abnormal flow and pressure fluctuations and results in transient-induced turbid flow mainly composed of fine particles ranging within 2–4 μm and constituting Fe, Si, and Al.

The Component Analysis of Foreign Substance Occurred in Water Distribution Networks

Abstract : Customers water quality complaints by foreign substance in local water service can be able to call the main cause bring the distrust for tap water and inhibiting the rate of drinking water. In this study, foreign substances were collected in the target region. Foreign objects were subjected to qualitative and quantitative analysis of compounds and elements components to reveal the cause of detection. Also, resolve the complaints by foreign substance and improve the reliability for tap water providing high quality water supply scheme. Collected substances at the water quality complaint area were included in inorganic compounds due to internal corrosion and aging pipeline, as well as organic compounds containing a large amount of carbon (C) and oxygen (O) component. To decide and reduce for foreign substance, objective assessment of pipe condition in target area was required. Key Words : Foreign Substance, Water Quality Complaints, Tap Water, Inorganic Compounds, Organic Compounds

A Study on the Method of Energy Evaluation in Water Supply Networks

The systematic analysis and evaluation of required energy in the processes of drinking water production and supply have attracted considerable interest considering the need to overcome electricity shortage and control greenhouse gas emissions. On the basis of a review of existing research results, a practical method is developed in this study for evaluating energy in water supply networks. The proposed method can be applied to real water supply systems. A model based on the proposed method is developed by combining the hydraulic analysis results that are obtained using the EPANET2 software with a mathematical energy model on the MATLAB platform. It is suggested that performance indicators can evaluate the inherent efficiency of water supply facilities as well as their operational efficiency depending on the pipeline layout, pipe condition, and leakage level. The developed model is validated by applying it to virtual and real water supply systems. It is expected that the management of electric power demand on the peak time of water supply and the planning of an energy-efficient water supply system can be effectively achieved by the optimal management of energy by the proposed method in this study.