• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.11
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• pp.1322-1331
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• 2004

This paper presents studies on the design of water hydraulic system and components to replace oil with tap-water as the pressure transmission medium in hydraulic systems. In order to improve the performance of water hydraulic system, the thermal and hydraulic properties of tap-water are first investigated. Based on these characteristics, the design parameters, such as the clearances of the moving parts, the cross-sectional area of pipes and relative roughness, are proposed so that the performance of water hydraulic system is the same as that of oil. In addition, the operating ranges, which show the possibility of using water hydraulic system, are examined.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.4
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• pp.411-420
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• 2005

Maintaining a good quality of drinking water produced through appropriate water treatment processes to the tap is as important as improving water quality in a water treatment plant (WTP). The quality of most tap water, however, does not have the same quality as that of the water produced in a WTP due to the contamination in the distribution system while they are delivered through pipes and water tanks. It is very important to maintain water quality in distribution system to water suppliers for consumer's health and safety. Furthermore, it is not possible to investigate the water quality of all points in the distribution system because the system has a wide area and very complex hydraulic characteristics. One economic solution to prevent water quality in distribution system from being deteriorated is monitoring several points that might have the least water quality in the distribution system. If the quality of water of the monitoring points selected by proper ways is better than the quality index of Drinking Water Quality Guidelines suggested by Korean Ministry of Environment, all other points in the distribution system would be safe to drink.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.707-717
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• 2011

Replacement of old water distribution pipes for protecting water quality induced by pipe corrosion requires enormous budget. Even after the replacement, however, corrosion can occur again at any times and, therefore, inhibitive measure of the corrosion will be not only economical but needed to diminish the consumers' distrust on tap water quality. In 2008, National Environmental Research Institute did a survey on 8 major drinking water source and proposed to establish the Langelier Saturation Index(LI) as a corrosion index in Drinking Water Quality Criteria. Among the water industries of Korea, K-Water is the only one that set up the level of pH over 7.0 and LI above -1.5 on yearly average basis. However, no systematic regulation including LI to inhibit the corrosive tendency has been established yet. In this paper, LI values out of 31 drinking water treatment plants were analyzed and two-stage control of LI value as a measure of corrosive tendency of water is proposed. Primarily, water treatment facilities may operate the system at a target LI value below -1.5. Following the investigation on the effect caused by adjusting the LI value on water quality and corrosiveness, it will be desirable to improve LI value below -1.0 in the long run. In addition to the LI, supplemental use of Larson's modified ratio (LMR) which incorporates hydraulic detention time will be necessary. Several methods to prove the inhibitive effect of improving the LI value on water quality have been also suggested.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.182-186
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• 2001

An acid forest surface soil as a land farming medium was treated with a water plant alum sludge at 0 to 18%. Indian mustard was grown in the treated soil in a greenhouse for 5 weeks and watered with pH 4 tap water adjusted with a mixed acid (1HNO$_3$: 2H$_2$SO$_4$) during plant growth. Changes in soil property, leachate chemistry, plant growth, and plant uptake of elements by the sludge treatment were determined. The alum sludge treatment increased buffer capacity to acidity, hydraulic conductivity, water holding capacity, and phosphate adsorption of the soil and decreased bulk density and mobility of small particles. The sludge treatment reduced leaching of Al, Mg, K, Na, and root elongation. Plant did uptake less amount of the cations and P but more Ca with the sludge treatment.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.697-704
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• 2008

Stormwater runoff from urban road area as non-point source has a tendency of including lots of pollutants at initial rain period. Recently, there are several cases of having installed treatment facilities for reducing pollution discharge from the impervious cover in urban area to prevent watershed environment from getting worse. The filtration type among non-point source treatment systems has been known as one of the most efficient system for treatment of non-point source pollutants. Therefore, various kinds of filter media such as expanded polypropylene(EPP), granular activated carbon, zeolite, perlite, illite, sand, gravel has been developed. This study was conducted to verify performance and hydraulic characteristics of filter media as measures for non-point source. The experiment was carried out to evaluate applicability and variation of 4 kind of most popular filter media(EPP, GAC, Zeolite, Perlite) in headloss with elapsed time and influent flow rate and to obtain data base that could be used to establish management plan for road runoff treatment. In experiment by tap water, it showed that EPP and perlite those are floatable materials showed stable operating performance and lower headloss than the others.

• Journal of Korea Water Resources Association
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• v.56 no.7
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• pp.451-460
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• 2023

In this study, the risk of red water and turbid water occurrence was analyzed by classifying it into detachment risk and deposition risk. First, risk factors for red water and turbid water were determined, and hydraulic analysis was conducted considering seasonal water consumption. The applied area was Cheongju City, and the risk analysis was conducted across 13 areas, and the areas with high deposition risk and high detachment risk were selected. The high risk of both detachment and deposition can be judged as an area with a very high probability of causing water quality problems. The areas with the highest deposition risk and detachment risk are the old towns of Nae deok1-dong and Yul1yang-dong, which are the oldest areas in Cheongju City with an age of more than 30 service years of pipe installation. By analyzing the risk of deposition and detachment, it will be possible to strengthen the maintenance function of the water supply network to provide the safe water to citizens and increase their confidence for tap water.