• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.599-609
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• 2017

Desalination plants have been recently constructed in many parts of the world due to water scarcity caused by population growth, industrialization and climate change. Most seawater desalination plants are designed with a submarine pipeline for intake and discharge. Submarine pipelines are installed directly on the bottom of the water body if the bottom is sandy and flat. Intake is located on a low-energy shoreline with minimal exposure to beach erosion, heavy storms, typhoons, tsunamis, or strong underwater currents. Typically, HDPE (High Density Polyethylene) pipes are used in such a configuration. Submarine pipelines cause many problems when they are not properly designed; HDPE pipelines can be floated or exposed to strong currents and wind or tidal action. This study examines the optimal design method for the trench depth of pipeline, analysis of on-bottom stability and dilution of the concentrate based on the desalination plant conducted at the Pacific coast of Peru, Chilca. As a result of this study, the submarine pipeline should be trenched at least below 1.8 m. The same direction of pipeline with the main wind is a key factor to achieve economic stability. The concentrate should be discharged as much as high position to yield high dilution rate.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.4
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• pp.85-93
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• 1996

This study is to make a comparison between the node method and the pipeline method for the analysis of the water distribution systems. For these purposes, the two methods were applied to a pipeline system in series, an artificial distribution network and a real distribution network. The results are as follows. 1. The difference between the results of the two methods was increased with the increase of the hydraulic gradient and the length between two adjacent nodes. 2. When all pipe lengths between two adjacent nodes were larger than 200~300m and have the steep hydraulic gradient, it was found that the results of the two methods showed high differences. 3. The difference between the results of the two methods were negligible in the case of the real distribution system in which only 12% whole pipelines were longer than 30m and the longest pipe length was 850m.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.481-489
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• 2016

Method of characteristic(MOC) has been widely used as a transient analysis technique for pressurized pipeline systems. There are substantial studies using MOC for the water hammer triggered through instantaneous valve closures, pump stoppage and pump startup for pipelines systems equipped with a centrifugal pump. Considering restrictions of MOC associated with courant number condition for complicated pipeline systems, an impulse response method(IRM) was developed in the frequency domain. this study implements the impact of centrifugal pump using transfer function in frequency domain approach. Using pump performance curve and the affinity law, this study formulated transfer functions which relate complex pressure head at upstream of pump system to that of downstream location. Simulations of simple reservoir-pump-valve system using IRM with formulated transfer function were similar to those obtained through MOC.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.1
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• pp.96-111
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• 1996

The failure of water pipelines is progressed by several compound factors and the collection and analysis of data about pipeline failure are inevitable for effective pipeline rehabilitation. Data analysis of pipeline failure was already performed in USA and Europe. Based on such phenomena, failure characteristics about metropolitan pipelines in Korea were analyzed: The conclusions of this study are as followings. 1. The failure cause of pipelines can be classified into natural cause and artificial cause. Artificial cause is 32% of total causes, so artificial failure as several constructions happens frequently in Korea. Although the failure by old pipe is greatest of any other causes m classtfied cause, failure cause is not classified in detail now. 2. The damaged part of pipelines is affected by cities, distribution system inventory, bedding conditions, and so on. In this study, the failure of pipeline body(67%) is greater than the failure of pipeline joint(33%) in natural failure. 3. In regard to pipe materials, failure rate of DCIP(0.8456), PEP(0.7288), and GSP(0.6643) is greater than that of CIP(0.3985) and CWSP(0.2348). 4. Usually, faIlure rate is increased in proportion to diameter of pipeline. In this study, CIP, DCIP, and CWSP have clear trends. But the trends of PEP is reverse, the case of GSP, HP is obscure due to data shortage. 5. There are no direct relationships between burial age and failure rate of pipelines. 6. Annual breaks and winter(Nov.~Feb.) breaks of pipelines are investigated. As a result, WInter breaks to annual breaks of CIP is 51.3%(Seoul), 51.1%(Taegu),38.7%(Pusan). This phenomena have direct correlation with average winter temp. of cities.

• 수도
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• v.22 no.2 s.72
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• pp.76-103
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• 1995

• 수도
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• v.22 no.5 s.75
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• pp.93-120
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• 1995

• 수도
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• v.24 no.2 s.83
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• pp.15-27
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• 1997

• 수도
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• v.24 no.2 s.83
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• pp.94-104
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• 1997

• 수도
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• v.22 no.4 s.74
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• pp.64-95
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• 1995

• 수도
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• v.23 no.3 s.78
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• pp.124-134
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• 1996