• Tunnel and Underground Space
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• v.18 no.2
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• pp.91-97
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• 2008

In this paper, in-situ technique for measuring hydraulic conductivity of Excavation Disturbed Zone (EDZ) in a direct way and its application to an Underground Research Laboratory (URL) site were introduced. It was understood that both the EDZ oriented test equipment as a hardware and analysis/evaluation technique as a software should be integrated for upgrading a quality of estimated EDZ hydraulic conductivity. The well-estimated EDZ hydraulic conductivity is expected to enhance a reliability of stability evaluation for caverns under groundwater table and design of a waterproof or drainage system as well as a grout system.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.701-706
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• 2006

Groundwater heat pump systems are the oldest of the ground-souce systems and it has various type. Standing column well type are must be located in hard rock geology site and produce sufficient water for the conventional open loop system. These system are indirect type(the building circulating loop and ground water are intercept). Existence of the exchanger the foundation protect water quality to use of open loop. The design of open loop system are concern on the power requirements. An experimental study was analysis the extremely heating operation COP of ground water heat pump system. Operation efficiency of the 50RT systems shows that, COP $2.9{\sim}5.0$ in heating operation. And generally it shows 3.4.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.581-587
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• 2021

In recent years, contamination of drinking water sources has emerged as a serious social problem, such as a large number of impurities in tap water or groundwater or the supply of suitable water due to rust of pipes. Although the government and public institutions are implementing various measures to protect water sources, they cannot improve water quality in a short period of time because of the enormous cost involved. Therefore, in recent years, preference has been given to a device that converts tap water, which is hard water, into soft water by installing a separate water softener at the faucet from which tap water is discharged. However, the existing filtration device has a problem that filtration performance is gradually lowered when impurities accumulate in the filter, requiring continuous filter replacement. In this study, the optimal design of the filter housing was performed to develop a water softener that can be washed when impurities accumulate on the filter inside the water softener connected to the faucet. For optimal design of the filter housing, fluid and fluid-structural interaction analysis were performed on the design pressure to determine the shape and thickness of the housing, and design review was performed through prototype.

• Membrane and Water Treatment
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• v.10 no.1
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• pp.67-74
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• 2019

Apparent changes in the natural hydrologic cycle causing more frequent floods in urban areas and surface water quality impairment have led stormwater management solutions towards the use of green and sustainable practices that aims to replicate pre-urbanization hydrology. Among the widely documented applications are infiltration techniques that temporarily store rainfall runoff while promoting evapotranspiration, groundwater recharge through infiltration, and diffuse pollutant reduction. In this study, a laboratory-scale infiltration device was built to be able to observe and determine the factors affecting flow variations and corresponding solids removal through a series of experiments employing semi-synthetic stormwater runoff. Results reveal that runoff and solids reduction is greatly influenced by the infiltration capability of the underlying soil which is also affected by rainfall intensity and the available depth for water storage. For gravel-filled structures, a depth of at least 1 m and subsoil infiltration rates of not more than 200 mm/h are suggested for optimum volume reduction and pollutant removal. Moreover, it was found that the length of the structure is more critical than the depth for applications in low infiltration soils. These findings provide a contribution to existing guidelines and current understanding in design and applicability of infiltration systems.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.2
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• pp.283-294
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• 2023

APro, developed in KAERI for the process-based total system performance assessment (TSPA) of deep geological disposal systems, performs finite element method (FEM)-based multiphysics analysis. In the FEM-based analysis, the mesh element quality influences the numerical solution accuracy, memory requirement, and computation time. Therefore, an appropriate mesh structure should be constructed before the mesh stability analysis to achieve an accurate and efficient process-based TSPA. A generic reference case of DECOVALEX-2023 Task F, which has been proposed for simulating stationary groundwater flow and time-dependent conservative transport of two tracers, was used in this study for mesh stability analysis. The relative differences in tracer concentration varying mesh structures were determined by comparing with the results for the finest mesh structure. For calculation efficiency, the memory requirements and computation time were compared. Based on the mesh stability analysis, an approach based on adaptive mesh refinement was developed to resolve the error in the early stage of the simulation time-period. It was observed that the relative difference in the tracer concentration significantly decreased with high calculation efficiency.

• Journal of Environmental Health Sciences
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• v.46 no.5
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• pp.513-524
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• 2020

Objective: The main purpose of this study is to evaluate the environmental and biological exposure of local residents who consumed arsenic-contaminated drinking water for less than one year. Methods: As a part of water quality inspections for small-scale water supply facilities, surveys were conducted of residents of two villages that exceeded the arsenic threshold for drinking water. The environmental impact survey consisted of surveys on water quality, soil, and crops in the surveyed area. Biological monitoring was performed by measuring the separation of arsenic species in urine and total arsenic in hair. Results: In the results of biological monitoring, the concentrations of AsIII and AsV were 0.08 and 0.16 ㎍/L, respectively. MMA and DMA were 0.87 and 36.19 ㎍/L. There was no statistically significant difference between the group who drank arsenic-removed groundwater or water from the small-scale supply facility and the group who drank tap water, purified water, or commercial bottled water. Some of the water samples exceeded the arsenic threshold for drinking water. There were no samples in the soil or rice that exceeded the acceptable threshold. Conclusion: In the case of short-term exposure to arsenic-contaminated drinking water for less than one year, there were no significant problems of concern from the evaluation of biological monitoring after arsenic was removed.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.997-1001
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• 2006

Organic compost has been widely applied to the cropland because it has been thought as Environmentally Sound Agriculture (ESA) in Korea. In this study, two-year indoor rainfall experiments were performed. Surface runoff and groundwater volume from 10% and 20% slope plots were measured and water quality samples were collected and analyzed for BOD, COD, T-P and T-N. Flow weighted mean concentration (FWMC) values were computed to assess effects of various fertilizer treatments. FWMC BOD values for organic compost treated plots were higher than chemical fertilizer treated plots. FWMC BOD values for 20% slope plots were higher than those from those for 10% slope plots. The similar trends were found for COD and T-P. FWMC T-N values for chemical fertilizer treated plots were higher than organic compost treated plots. FWMC T-N values for 10% slope plots were higher than those for 20% slope plots. In Korea, excessive use of organic compost has caused extremely high levels of organic matter contents at the cropland. Since organic compost is very slow in releasing its nutrients to the soil, farmers usually apply excessive organic compost for immediate effects and maximum crop yields, which has been causing soil and water quality degradations. Therefore, thorough investigations for better nutrient management plans are needed to develop the ESA strategy in Korea.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.5
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• pp.333-341
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• 2014

To supply substitution water, $2m^3$ of capacity of rainwater harvesting system is designed calculating rainfall, catchment area and LPCD and has a effects to 34.4% of substitution water supply and 237 days of service day. Rainwater of drinking water quality was judged to be suitable except for bacteria problem, however, groundwater is exceeded in nitrate nitrogen, the evaporation residue and also bacteria, which means that the rainwater is suitable for use as water supply. In addition, to consider cost-benefit ratio, economic analysis conducted. The result is that B/C ratio of RWHS (10 years) is 1.70. It means total benefit is bigger than cost. Except to social factor in this study, there are a variety of benefit such as flood or drought prevention, educational effects inspiring water conservation awareness.

• Economic and Environmental Geology
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• v.46 no.6
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• pp.581-592
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• 2013

In this study, the chemical components (pH, $HCO_3{^-}$, $Cl^-$, and $SO_4{^{2-}}$) of water sources (surface water, groundwater, and spring water) in 1930s were compared to those in the period of 1985-1992 in Jeju Island. By the comparison, pH values and $Cl^-$, and $SO_4{^{2-}}$ concentrations in 1930s appeared similar to those in the second period (1985-1992) while $HCO_3{^-}$ increased about the six times in the second period. Such a great increase of $HCO_3{^-}$ concentration may be caused by the increase of carbon dioxide in the atmosphere due to industrialization.

• Journal of Wetlands Research
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• v.12 no.1
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• pp.23-31
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• 2010

Chlorinated aliphatic hydrocarbons (CAHs) such as tetrachloroethylene (PCE), 1,1,1-trichloroethane (1,1,1-TCA) are the contaminants most frequently found in soil and groundwater. They have a potential to be toxic to and persistent in environment. This study is focused on selection of zero-valent metal and ores for the removal of high concentration PCE or 1,1,1-TCA and mixture of two compound. For the screening of suitable metals, we measured dechlorination rate, removal capacities and economics by using batch reactor test. This results suggest that removal rate and dechlorination of high quality iron and zinc are higher than slag and nature ores like zinc and manganese. Among nature ores, zinc ores(64% purity) have highest removal capacities. And in economics zinc ores is 10 times better than high quality metal tested. We conclude zinc ore is most suitable metal for the removal of PCE or 1,1,1-TCA.