• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.131-138
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• 2007

A rainwater utilization facility consists of its catchment area, treatment facility, storage tank, supply facility and pipes in general. The rainwater storage tank which occupies the largest area of the facility has been usually considered quantitatively for determining the storage capacity. Hence, there is little information on water quality improvement by sedimentation in a rainwater storage tank in operation. In this study, we measured the rainwater quality in a rainwater storage tank in operation during late spring and summer, and showed water quality improvement of turbidity removal of 25~46% by sedimentation in a rainwater storage tank under a fixed water level without inflow and outflow after runoff ceased. It is necessary to have a considerable distance between the inlet and outlet of the tank and, if possible, it is recommended that the design should allow for an effective water depth of over 3 m and supply rainwater near the water surface. The operation method which increases the retention time by stopping rainwater supply for insuring low turbidity is recommended when the turbidity of rainwater runoff is high. And also more efficient operation and maintenance of the rainwater utilization facility is expected through the tailored design and operation of the facility considering particle removal and behavior.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1147-1157
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• 2009

Recently this country has carried out the coast reclamation centering on the west and south coast for effective practical use of a country, considering purchase of materials and environmental problem, and carrying into effort the reclamation method after dredging the ground in the ocean. In this large scale ocean dredging reclaiming work, prediction the ground subsidence after reclaiming is very important for not only expense lose by overestimation or underestimation but also hereafter the best suited project establishment. this study carries out sedimentation and self weight consolidation in each cases and searches the features to analyze effect on kinds of soil of ground before dredging, abandonment height when it abandons momentary, void ratio, difference of abandonment height when it abandons by stages and difference of particle content of spoil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3336-3344
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• 2014

The purpose of this study is small scale coagulation module is developed and demonstrated through a lab-scale test. Recent as a sewage treatment rate increases, have heightened the interest in the necessity on the nonpoint source and developing a small processing unit has been increased. Coagulation sedimentation module in this study is additional growth of floc through swirling in the outside zone, reduction of microstructure floc number and the internal settling zone through vertical/level flow complex sedimentation method after the coagulation process precipitation method as an effective high separation efficiency can be divided was also assessed. Coagulation sedimentation module can increase the load factor was 4.4 times compared to conventional clarifier base on the same volume and surface area through vertical/level flow. In this study, this process was selected formation and maintenance of swirling and uniform flow distribution in the internal settling zone as an important design factor, to derive its FLUENT was used to characteristics of the flow model. Through the simulation of swirling, influent velocity, dimensions of external basin, hopper depth of bottom cone was determined and through analysis of velocity distribution, flow distribution detailed specifications are derived like as diameter and number of effluent hole. Lab-scale($120{\ell}/hr$) test results, influent of 300~800 NTU to less than 10 NTU without polymer feeding was able to operate in the 20minutes retention time(surface loading rate $37.3m^3/m^2$-day), and through analysis FLUENT the possibility of using design parameters were derived.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.89-98
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• 2009

In this research, settling tests with marine clays in Korea and extensive literature review were performed to investigate the characteristics of sedimentation and consolidation so that their behaviors during dredging and reclamating could be evaluated. Design parameters related to Yano's method (1985), one of experimental approaches having been used widely in Korea to estimate sedimentation and consolidation, were analyzed and their proprieties were reassessed. For samples from four different sites of south and west coasts in Korea respectively, settling tests with 1m height of columns were carried out, changing initial water content and height of sample in order to evaluate settling and consolidation characteristics of them from analyzing test results. More reliable regression curves than values from literature review were obtained as analyzing test results of estimating coefficient of sedimentation/ consolidation and initial setting velocity with changing initial water content. Relation between height of soil solid and surface height of slurry at the stages of initiation and termination of consolidation was also assessed. Finally, for marine clays of south and west coasts of Korea, ranges and average values of these design parameters were evaluated and typical empirical equations between these design parameters were also proposed. On the other hand, comparisons of characteristics of sedimentation and consolidation between marine clays from south coast and them from west coast were also performed.

• Proceedings of the KSRS Conference
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• v.1
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• pp.247-249
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• 2006

The objective of this study is to detect a inter-tidal topographic change in a decade. Waterline extraction is a one of widely used method to generate digital elevation model (DEM) of tidal flat using multi-temporal optical data. This method has been well known that it is possible to construct detailed topographic relief of tidal flat using waterlines In this study, we generated two sets of tidal flat DEM for the southern Ganghwado. The DEMs showed that the Yeongjongdo northern tidal flat is relatively high elevation with steep gradients. The Ganghwado southern tidal flat is relatively low elevation and gentle gradients. To detect the morphologic change of tidal flat during a decade, we compared between early 1990's DEM and early 2000's DEM. Erosion during a decade is dominant at the west of southern Ganghwado tidal flat, while sedimentation is dominant at the wide channel between the southern Ganghwado and Yeongjongdo tidal flats. This area has been commonly affected by high current and sedimentation energy. Although we are not able to verify the accuracy of the changes in topography and absolute volume of sediments, this result shows that DEM using waterline extraction method is an effective tool for long term topographic change estimation.

• Journal of the Korean GEO-environmental Society
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• v.17 no.2
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• pp.13-22
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• 2016

Accurate settlement estimation of dredged soft soil deposits is significantly important to prevent potential disasters during land reclamation. An application of the non-linear finite strain consolidation theory is inevitable in dealing with a very soft ground formation such as dredged fill. In this paper, a series of the sedimentation-consolidation test, self-weight consolidation test and CRS test were conducted to clarify sedimentation and consolidation characteristics of dredged fill in the Songdo area, Incheon. In addition, the settlement of dredged fill was numerically simulated using the PSDDF program. The dredged soil obtained from the Songdo area was classified as low-compressible silt (ML) based on USCS (Unified Soil Classification System), and the final bulking factors were estimated to be 1.56 and 1.17 by Yano's method and the numerical simulation, respectively. This difference is attributable to relatively high reclaimed height and large permeability of dredged soil in this region.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.5
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• pp.515-525
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• 2014

Recently, because of increasing in downpour and typhoon, which are caused by climate changes, those sedimentation disasters, such as landslide and debris flow, have become frequent. Those sedimentation disasters take place in natural slope. In order to predict debris flow damage range within wide area, the response model is more appropriate than numerical analysis. However, to make a prediction using Random Walk Model, the regional parameters is needed to be decided, since the regional environments conditions are not always same. This random Walk Model is a probability model with easy calculation method, and simplified slope factor. The objective of this study is to calculate the optimal parameters of Random Walk Model for Umyeon mountain in Seoul, where the large debris flow has occurred in 2011. Debris flow initiation zones and sedimentation zones were extracted through field survey, aerial photograph and visual reading of debris flow before and after its occurrence via LiDAR DEM.

• Journal of Conservation Science
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• v.35 no.6
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• pp.664-669
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• 2019

Yeonpyo-beob is a method of manufacturing pigments using bamboo trunk and glue solution. Glue solutions of concentrations 1, 5, and 10% were employed to manufacture pigments, and the characteristics of pigment manufacturing were analyzed according to these concentrations. The pigment manufacturing process can be divided into holding and drying phases. The holding phase involves the sedimentation of relatively large particles, whereas the drying phase involves the sedimentation of small particles. The layers formed during the drying phase have almost similar forms regardless of the concentration of the glue solution. If the concentration of the glue solution is low in the holding phase, the particles are mixed and the formation of a layer is difficult. In contrast, when the concentration of the glue solution is higher, the layer of the pigment is more distinct. These results confirmed that the differences in viscosity due to the variation in the concentration of the glue solution affect the sedimentation velocity of the pigment particles, thereby affecting the formation of the layer of the pigment and the pigment manufacture. Consequently, applying 10% glue solution to reduce the sediment velocity is deemed suitable for the stratification of the pigment particles and the manufacture of pigments.

• Journal of the Korean GEO-environmental Society
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• v.2 no.3
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• pp.5-15
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• 2001

The purpose of this study is to find sedimentation patterns variation before and after the Saemangeum reclamation. Water circulations before and after the Saemangeum reclamation are calculated diagnostically and prognostically from the water temperature, salinity data, wind data and tidal residual current. Three dimensional movements of injected particles due to currents, turbulence and sinking velocity are tracked by the Euler-lagrange method. The dispersion range of soil grain for one and three day after releasing in the Geum river indicates that the soil grain was sedimented coastal area of Janghang and outer harbor of Kunsan. The soil grain moves a quite distance from the release point when size of soil grain is a small. These results indicate that size of soil grain and residual current is greatly influenced on the dispersion range of soil grain.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.421-427
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• 1992

The study was basically carried out to establish the appropriate condition for applying the Westergren method for erythrocyte sedimentation rate(W-ESR) in Throughbred racehorses at recess. To do this, we examined the correlationship among some factors including the kind of anticoagulants, optimal ambient temperature and reading time for W-ESR in healthy racehorses. The difference between the blood samples treated with only 3.8% solution of sodium citrate(SC) and both EDTA and SC as a coagulant, there was not recognized any significant difference(p<0.05) in the levels of W-ESR irrespective of the ambient temperature of $20^{\circ}C$ or $30^{\circ}C$. The best optimal ambient temperature for W-ESR in horses was proved at $30^{\circ}C$ resulting from the tendency of the most reduced dispersion in mean values analyaed from repeatly 4 times to the same blood samles compared with those of $10^{\circ}C$ and $20^{\circ}C$. The optimal reading time was determined as 60 minutes(Y=237.2~4.1X, $r^2=0.998$) and 70 minutes(Y=247.8~4.2X, $r^2=0.999$) under the same temperature of $30^{\circ}C$; the latter showed the better result on the basis of the correlation of packed cell volume(PCV) and ESR values. About 13 healthy racehorses, we compared the real values of W-ESR respectively obtained at 60 minutes and 70 minutes at $30^{\circ}C$ with the anticipated values of PCV by means of the analysis of linear regression equitation. As the result of this, the strong correlation between both of them was confirmed. For practical use of W-ESR in Thoroughbred racehorese, we can recommend the condition of 60 or 70 minutes for the optimal reading time as well as $30^{\circ}C$ for the best ambient temperature.