• Title/Summary/Keyword: 랑겔리어 지수

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Corrosion control technology in water pipes by adjusting the corrosivity of drinking water : effect and impact of the lime dispersion system (수돗물 부식성 제어를 통한 수도관 부식방지기술: 석회수 분산화장치를 이용한 미네랄 공급 효과와 영향 분석)

  • Han, Keum-Seok;Park, Young-Bok;Kim, Seong-Jae;Kim, Hyen-Don;Choi, Young-June;Park, Ju-Hyun;Woo, Dal-sik;Hong, Seong-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.32 no.3
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    • pp.235-242
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    • 2018
  • Corrosion inhibitors including calcium hydroxide have been used to prevent corrosion in the pipes for tap water supply. The corrosion index (i.e., Langelier Index) differs by area and water quality. The corrosion indices of the areas studied differed by more than 2.0. The 'homogenized' calcium hydroxide was added to the treated water at the K water treatment plant, in order to increase the value of the corrosion index and the concentration of calcium. As the result, the concentration of calcium was increased while the turbidity and pH changed little. The corrosion rate of the tap water with the 'homogenized' calcium hydroxide could be slowed down pretty much. The results suggested that the technology of 'homogenization' of calcium hydroxide can applied to tap water and desalinated water to prevent corrosion in water pipes even in corrosive pipes.

Characterization of Area Installing Combined Geothermal Systems : Hydrogeological Properties of Aquifer (복합지열시스템에 대한 부지특성화: 대수층의 수리지질학적 특성)

  • Mok, Jong-Koo;Park, Yu-Chul;Park, Youngyun;Kim, Seung-Kyum;Oh, Jeong-Seok;Seonwoo, Eun-Mi
    • The Journal of Engineering Geology
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    • v.27 no.3
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    • pp.293-304
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    • 2017
  • This study was performed in order to hydrogeological analysis of aquifer, which is a necessary part for evaluating the efficiency of the combined well and open-closed loops geothermal (CWG) systems. CWG systems have been proposed for the effective utilization of geothermal energy by combining open loop geothermal systems and closed loop geothermal systems. Small aperture CWG systems and large aperture CWG systems were installed at a green house land with water curtain facilities in Chungju City. Aquifer tests include pumping tests and step-drawdown tests were conducted to analyse hydrogeological characteristics of aquifer in the study area. The transmissivity was estimated in the range of $13.49{\sim}58.99cm^2/sec$, and the storativity was estimated in the range of $1.13{\times}10^{-5}{\sim}5.20{\times}10^{-3}$. The geochemical analysis showed $Ca^{2+}$ ion and ${HCO_3}^-$ ion were dominant in groundwater. The Langelier Saturation Index and the Ryznar Stability Index showed low scaling potential of groundwater. In the analysis of vertical water temperature change, the geothermal gradient was estimated as $2.1^{\circ}C/100m$, which indicated the aquifer was enough for geothermal systems. In conclusion, groundwater is rich, can stably use geothermal heat, and it is less likely to cause deterioration of thermal energy efficiency by precipitation of carbonate minerals in study area. Therefore, the study area is suitable for installation of the combined geothermal system.