• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.27-33
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• 2012

The purpose of this study is to evaluate the field applicability of Quantum Stick in scale deposit prevention for subway tunnels in Seoul. This technology was installed into drainpipes and its performance was monitored through occasional site visits. SEM and EDS were also performed on scale collected from these drain pipes. Results showed a decrease in scale deposits due to Quantum Stick treatment. In the field test, the device was found to be effective in preventing scale formation in new pipes as well as reducing existing scale in previously installed pipes. However, further investigations are necessary to account for various environmental conditions. In conclusion, the results indicate that molecular Vibration technology is effective in suppressing scale formation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.822-826
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• 2015

This study investigated the possible use of vibration from polyvinylidene fluoride(PVDF) film to enhance the performance of the deteriorated tunnel drainage due to physical/chemical clogging of the fine particles through a series of laboratory experiments. The test program was consisted of two different experiments, fundamental investigation and drainage model test. In the fundamental investigation, flow of clay slurry mixed with 50% water (freshwater and brine) on PVDF film with various frequencies was examined. In the model tests, slurry clogging to the woven fiber attached to drainage pipe and its reduction by vibration was investigated. Results of the experiment show that vibration from PVDF film enhances the drain performance significantly. Based upon the investigation, it gives an essential data that are needed for a potential use of hybrid drainage system with PVDF.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.263-273
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• 2020

With the change of the agricultural environment (increased rice production, decreased rice consumption, and rice production policies), converting paddy fields into upland fields is an increasing trend. In terms of conversion into upland fields, subsurface drainage is one of the most important factors for good field crop growth. This study evaluates the performance of a subsurface drainage culvert system in paddy fields and reclaimed lands. The obtained results are briefly summarized as follows: 1) After a comparative evaluation of several subsurface drainage culvert systems, including excavated subsurface drainage and non-excavated subsurface drainage types, type 3 (non-excavated, perforated drain pipe 50 mm, filter mat B50 cm, subsoiling 70 cm and culvert spacing 5 m) shows relatively high values among four types in terms of effectiveness (subsurface discharge capability) and economic efficiency (construction cost). 2) Type 3 has proven that it is suitable for design standards of discharge capacity through field tests performed in paddy fields (three sites: Gong-geom, Gae-san, Juk-san) and reclaimed lands (two sites: Gum-ho, Mi-am). 3) In the experiment of Sesamum indicum growth according to the existence of a drainage system, Sesamum indicum growth with a subsurface drainage culvert system had good value in terms of plant shoot and root length, shoot fresh and dry weight, and root fresh and dry weight).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.930-934
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• 2006

In this study, we conducted water-quality analysis of wastewater and in-situ flow measurement using automatic flow rate measuring instrument to identify characteristics of wastewater in urban areas, and collected samples in gutter fur storm water drain, rainfall bucket, and aqueduct of pipe from roof, and outfalls of basins to examine the contribution by pollution origins such as base wastewater, atmospheric washing, runoff by roof surface, runoff by road surface, erosion of sewer sediment. In the result, the concentration of pollutants reached peak in the beginning of rainfall due to first flush, was 3 to 10 times higher than average concentration of dry period, and was lower than that of dry period due to dilution of storm water. In the analysis of the contribution by pollution origins, the ratio of load by sewer sediment resuspension to the total pollution load was 54.6% fer COD, and 73.3% fur SS. Accordingly, we can reduce the total pollutant load by periodical dredging and washing of sewer sediment, and control the loadings by overflow of combined sewer overflows.

• Journal of Korean Society of Forest Science
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• v.100 no.1
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• pp.25-33
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• 2011

The purpose of this study is to develop a standard calculation program of forest road drainage facilities that may help forest road designers to design forest road drainage facilities more conveniently and precisely. Especially, the characteristics of this program is that the forest road designers may calculate the amount of outflow in the basin using rainfall intensity data conveniently, without the data designers should acquire through site measurements when they carry out indoor preliminary measurements before they go out for outdoor measurements. In this manner, excessive design may be restrained by offering minimum standard calculation for drainage structures. And also this study was designed to facilitate proper layout of drainage structures by calculating outflow discharge of each basin where forest roads will be installed. Especially, this study will contribute to leveling-up of forest design techniques as the researcher has prepared the reports on whole process of drain pipe installation and provided them in the form of computer file or printout, which show a rational design process, and make it possible to modify in case of an error.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.923-929
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• 2022

The Chuncheon Mullori area is an underprivileged area of water welfare where local water supply is not supplied, and it is supplying water to the villages with small water supply facilities using lateral flow and groundwater as water sources. This is an area with poor water supply conditions, such as relying on water trucks due to water shortages during the recent severe drought. Therefore, in order to solve the problem of water shortage during drought and to prepare for the increasing water demand, a sand dam was installed along the valley, and this facility has been operating since May 2022. In this study, repeated simulations were performed according to the hydraulic conductivity of the filler material and the storage coefficient value for the inflow condition for about two years from mid-March 2020 to mid-March 2022. For each case, the amount of discharge through the perforated drain pipe was calculated. Overall, as the hydraulic conductivity increased, the amount of discharge and its ratio increased. However, when the hydraulic conductivity of the second floor was relatively low, the amount of discharge increased and then decreased as the hydraulic conductivity of the third floor increased. This is considered to be due to the fact that the water level was kept low due to the rapid drainage compared to the net inflow into the third floor because the water permeability of the third floor and the drainage coefficient of the drain pipe were large. As a result of simulating the flow of the open channel in the upper part of the sand dam as a hypothetical groundwater layer with very high hydraulic conductivity, the decrease in discharge rate was slower than the increase in the hydraulic conductivity of the hypothetical layer, but it was clearly shown that the discharge volume decreased relatively as the hydraulic conductivity of the virtual layer increased.

• Journal of Radiation Protection and Research
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• v.39 no.1
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• pp.61-64
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• 2014

Radioactive materials are in use and have many applications from the generation of electricity to the purposes of research, industry and medicine such as diagnosis and therapy. In the course of their use some of radioactive substances may be discharged into the environment from facilities using the unsealed radioactive materials, which are main artificial sources occurring the public exposure. Discharges are in the form of gases, particles or liquids. This paper provides procedures to estimate the level of the public exposure based on the conservative assumptions and simple calculations in the facility using unsealed liquid sources. They consist of two processes; (1) to calculate maximum concentration of gaseous effluents discharged through the exhaust pipe and average concentration of liquid effluents discharged through the drain of the storage tank, (2) to compare each of them to numerical guidances for the discharges of radioactive gaseous and liquid effluents mentioned in the related notification. For this purpose followings are assumed properly; daily usage, form and dispersion rate of radionuclides, daily amount of radioactive liquid waste and exhaust and drainage equipment. The procedures are readily applicable to evaluate environmental effects by planned effluent discharges from facilities using the unsealed radioactive materials. In addition they may be utilized to obtain practical requirements for radiation safety control necessary for the reductions of the public exposure.

• Journal of Environmental Health Sciences
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• v.40 no.1
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• pp.47-54
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• 2014

Objectives: The purpose of this study is to evaluate the characteristics of leachate discharged from livestock burial sites in Gangwondo resulting from foot-and-mouth disease by monitoring the water quality at the survey tube-wells installed near livestock burial sites in order to investigate the effect of the leachate on the quality of nearby underground water and suggest a water pollution level in accordance with water quality evaluation criteria. Methods: To minimize the secondary environmental pollution damage caused by leachate at burial sites of livestock killed by foot-and-mouth disease, this study analyzed the leachate directly discharged from burial sites and installed survey tube-wells within 300 meters of livestock burial sites and investigated water quality as a means to ascertain the environmental effect of the leachate from the burial sites. In accordance with environmental management guidelines on livestock burial sites, this research investigated the water quality in the survey tube-wells in fifty five burial sites in Gangwondo. The elements investigated were $NH_3$-N, $Cl^-$, $NO_3$-N, conductivity, and E. coli. Water quality was monitored from 2011 to 2013. Results: The water quality from the drain pipe at the location of leachate from livestock burial sites showed BOD 37,209 mg/L, COD 8,829 mg/L, $NH_3$-N 3,633 mg/L, and $Cl^-$ 580 mg/L. According to the monitoring results of water quality ($Cl^-$, $NH_3$-N, conductivity) at the survey tube-wells, there was suspicion that 13 out of 55 burial sites discharged leachate, five sites discharged highly concentrated leachate (13%): one in Gangneung, one in Wonju, and three in Cheorwon. Conclusion: It was judged that out of thirteen observation wells which showed a possibility of discharged leachate, three survey tube-wells have established the discharge effect of leachate at burial sites up to recently. Therefore, it is judged that it is necessary to continue monitoring them and devise additional measures.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1396-1408
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• 2020

Filtered containment venting system (FCVS) is one of the severe accident mitigation systems designed to release containment pressurization to maintain its integrity. The thermal-hydraulic behaviors in FCVSs are important since they affect the operation characteristics of the FCVS. In this study, a representative FCVS was modeled by RELAP5/Mod3.3 code, and the Station BlackOut (SBO) was chosen as an accident scenario. The thermal-hydraulic behaviors of an FCVS during long-term operation with two venting strategies (open-and-close strategy, open-and-non-close strategy) and the sensitivity analysis of important parameters were investigated. The results show that the FCVS can operate up to 250 h with a periodic open-and-close strategy during an SBO. Under the combined effects of steam condensation and water evaporation, the solution inventory in the FCVS increases during the venting phase and decreases during the intermission phase, showing a periodic pattern. Under this condition, the appropriate initial water level is 3-4 m; however, it should be adjusted according to the environment temperature. The FCVS can accommodate a decay heat power of 150-260 kW and may need to feed water for a higher decay heat power or drain water for a lower decay heat power during the late phase. The FCVS can function within an opening pressure range from 450 kPa to 500 kPa and a closing pressure range between 250 kPa and 350 kPa. When the open-and-non-close strategy is adopted, the solution inventory increases quickly in the early venting phase due to steam condensation and then decreases gradually due to the evaporation of water; drying-up may occur in the late venting phase. Decreasing the venting pipe diameter and increasing the initial water level can mitigate the evaporation of the scrubbing solution. These results are expected to provide useful references for the design and engineering application of FCVSs.

• Journal of Korea Water Resources Association
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• v.55 no.5
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• pp.345-356
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• 2022

A severe flooding occured at a small urban catchment in Daejeon-si South Korea on July 30, 2020 causing significant loss of property (inundated 78 vehicles and two apartments) and life (one casualty and 56 victims). In this study, a retrospective analysis of the inundation event was implemented using a physically-based urban flood model, H12 with high-resolution data. H12 is an integrated 1-dimensional sewer network and 2-dimensional surface flow model supported by hybrid parallel techniques to efficiently deal with high-resolution data. In addition, we evaluated the impact of the flooding barriers which were installed after the flood disaster. As a result, it was found that the inundation was affected by a combination of multiple components including the shape of the basin, the low terrain of the inundation area located in the downstream part of the basin, and lack of pipe capacity to drain discharge from the upstream during heavy rain. The impact of the flooding barriers was analyzed by modeling with and without barriers on the high-resolution terrain input data. It was evaluated that the flood barriers effectively lower the water depth in the apartment complex. This study demonstrates capability of high-resolution physically-based urban modeling to quantitatively assess the past inundation event and the impact of the reduction measures.