• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.5
• /
• pp.609-614
• /
• 2014

Researcher of this study improved conventional circle secondary settling basin, through the way such as extend of inlet pipe length, introduction of device for inducting uniforming of flow, keeping of height of sludge interface. Also, we compared conventional circle settling basin to improved circle settling basin the water treatment efficiency. Result of research, when SVI is average 117, improvement rate of SS and BOD were 51.0%, 37.0% approximately compared to conventional settling basin. And when SVI is average 178, improvement rate of SS and BOD were 22.7%, 36.0% approximately. Also when SVI is average 196, improvement rate of SS and BOD were 24.7%, 30.3% approximately. When it's winter, improvement rate of SS, BOD, COD, TN and TP were 20.6%, 17.9%, 13.9%, 13.5%, 12.4% approximately. Therefore, we can be the judge, this improved settling basin can be used as the final settling basin in the waste water treatment plant.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.3
• /
• pp.383-394
• /
• 2013

A sedimentation basin is used to remove suspended sediments which can cause abrasive and erosive wear on hydraulic turbines of hydropower plants. This sediment erosion not only decreases efficiency of the turbine but also increases maintenance costs. In this study, the three-dimensional numerical simulations were carried out on the overseas hydropower project. The simulations of flow and suspended sediment concentration were obtained using FLOW-3D computational fluid dynamics code. The simulations provide removal efficiency of a sedimentation basin based on particle sizes. The influence of baffles on the flow field and the removal efficiency of suspended sediments in the sedimentation basin has been investigated. This paper also provides the numerical simulations for sediment-induced density currents that may occur in the sedimentation basin. The simulation results indicate that the formation of density currents decreases the removal efficiency. When a baffle is installed in the sedimentation basin, the baffle provides intensive settling zones resulting in increasing the sediments settling. Thus the enhanced removal efficiency can be achieved by installing the baffle inside the sedimentation basin.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.1
• /
• pp.19-26
• /
• 2006

Andong and Imha reservoir adjoins each other, but turbid water shows too much different when it rains. The characteristics of geological rock in basin and agricultural area around river boundary are pointed out as the major reason of turbid water of Imha reservoir. This study analyzed rock type of topsoil layer using soil map by National Institute of Agricultural Science and Technology (NIAST). Among rock types, sedimentary rock affects on the occurrence of turbid water. In the analysis of sedimentary rock type, the distribution of sedimentary rock of Imha basin shows 1.87 times higher than that of Andong basin. Also, the distribution of sedimentary rock of Imha basin shows higher than that of Andong basin within 1,600m from river channel in according to the buffer zone of river boundary. And Agricultural area of Imha basin shows higher than that of Andong basin in analysis of land cover within 1,600 m from river channel. As this agricultural characteristics of Imha basin, cover management factor of Imha basin represents more higher that that of Andong basin.

• Journal of the Korean association of regional geographers
• /
• v.8 no.2
• /
• pp.229-246
• /
• 2002

This study is a contribution to the geographical understanding of Daejeon Area, playing the role of principal center of Choongchong Province. This area has been urbanized associated with Daejeon Basin, an important natural unit in the middle part of South Korea. In order to understand Daejeon Area in geographer's view, it is necessary to elucidate geomorphological environment of Daejeon Basin and urban expansion pattern associating with it. Our research is converged into dual objectives: one, description and interpretation of basin's landforms; other, urban expansion relating with geomorphological condition. Daejeon's urban expansion has progressed from the border zone of Daejeon Basin toward into the basin, and then vice versa. Relating to rivers valleys in the basin, the urbanization in the basin has been extended from the river valleys of lower order toward those of higher order. Understanding of the geomorphological mosaique of Daejeon basin is an important base for that of urban mosaique of Daejeon City.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.2
• /
• pp.173-182
• /
• 1994

A numerical experiment on the effective discharge of waste materials caused in recirculating aquaculture basins was performed. The numerical model used in this study was a 4-level hydrodynamic and advection-diffusion model. Flow structures and settling processes of ss in the various mathematical model basins are discussed. The calculated flow fields of the numerical basin corresponded well with the measured velocity in field basin. In the cases of steep bottom slopes in 4/30, the non-dimensional tractive force($U{\ast}/U{\ast}_c$) which is all important parameter for the deposition pattern of waste materials was stronger than with the mild slope one. The settling pattern of ss depended considerably on the degree of bottom slope of basin. To concentrate deposited waste materials into the center discharge pipe, it is useful to design a cylindrical basin with a steeply conical bottom. In addition, to prevent movement of the deposit area away from the center, it is necessary to locate the circulating ducts at diametrically opposed points on the basin sides.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.5
• /
• pp.573-581
• /
• 2009

In the case that the average velocity within rectangular-shaped sedimentation basin is less than 1.5cm/sec, and Froude number less than $10^{-6}$, it can not be expected that the longitudinal baffle improves the sedimentation efficiency. Also, since relatively lower velocity increases the effect of geostrophic body force, asymmetric flow pattern on a plane occurs within the basin. From the results of CFD (Computational Fluid Dynamics) simulation, in the case that the highest velocity within rectangular-shaped sedimentation basin is over 1.5cm/sec, and Froude number over $10^{-6}$, it can be expected that the longitudinal baffle installed within rectangular-shaped sedimentation basin improves the sedimentation efficiency.

• Journal of the Korean earth science society
• /
• v.27 no.7
• /
• pp.757-767
• /
• 2006

Alluvial-plain deposits in the southeastern part of the Eumsung Basin (Cretaceous) are characterized by coarse-grained channel fills encased in purple siltstone beds. It represents distinct channel geometry, infill organization, and variations in facies distribution. The directions of paleocurrent, sedimentary facies changes, and channel-fill geometry can be used to reconstruct a channel network in the alluvial system developed along the southeastern margin of the basin. The channel-fill facies represent downstream changes: 1) down-sizing and well-sorting in clast and martix of channel fills and 2) internal organization of scour fill or gravel lag and overlying cross-stratified, planar-stratified beds. These findings suggest multiple stages of channel-filling processes according to flooding and subsequent stream flows. In the small-scale pull-apart Eumsung Basin (${\sim}7{\times}33km^2$ in area), vertical-stacked alluvial architecture of the coarse-grained channel fills encased in purple siltstone is expected to result from episodic channel shifting under a rapidly subsiding setting.

• Korean Journal of Environmental Biology
• /
• v.36 no.4
• /
• pp.554-557
• /
• 2018

A catch basin sump is one major habitat for mosquito larvae, especially in urban areas. This study developed a device for mosquito control, specifically for the catch basin sump. It consists of a housing, is a little smaller than the catch basin sump, numerous floating materials, which the key component for mosquito control, and mesh nets. The small balls or pyramid-shaped floating materials inhibit mosquito enclosures and spawning by significantly decreasing the surface area of the water, which is essential for the mosquito life cycle. These floating materials were designed to keep the water flowing. The mesh nets were installed to prevent the outflow of floating materials. The efficiency of the floating materials was tested with 3 conditions (1, 2, 3 layers of floating materials) and a control group. The emergence of mosquito adults decreased by 20% in one-layer, and 70-80% in second and third layers. Therefore, this device is expected to certainly contribute to mosquito population control in the catch basin sump.

• Journal of the Korean association of regional geographers
• /
• v.4 no.1
• /
• pp.121-134
• /
• 1998

In this study, the satellite images and the GIS technique are used to select the basin characteristics parameters as the basis of water resources management of river basin. The study area is Geum-ho river basin and the hydrologic characteristics data are computed through the database of the basin characteristics parameters classified by subjects with 35 maps correspond to the study basin of 1:25,000 scale as the basic map. As the result, the drawing up of land use map through satellite image processing that provides the quantitative informations for the land is very efficient to analysis the extensive land use information of the basin, and exact analysis of mass surface data is possible and the feasibility of statistic computation between spatial subjects as it superpose on other subject map is ascertained. It is thought also that the analysis of the basin characteristics data can be utilized very effectively for the basin management and the analysis of basin surface area, once it is expressed numerically for database, since the superposition analysis with different subject map and the correlative analysis with the property data are possible although the tracing process of each subject in the basic map is not efficient. Especially, modification and renewal of the data for the change of land surface become easy, therefore more rapid and exact selection of the basin characteristics data and the construction of more efficient basin management plan are possible.

• Journal of the Korean Geophysical Society
• /
• v.7 no.2
• /
• pp.99-112
• /
• 2004

The Basin, a marginal basin located between the Antarctic Peninsula and the South Shetland Islands, is consist of three small basins, the Central, Eastern, Western Basins. Seismic data obtained on December 1995 show well-defined spreading ridges, basement highs, faults, morphology of the basin, distribution of sediments, crustal and sedimentary deformation, diapirs, and contourites. The main spreading axis of the Central Bransfield Basin connecting Deception and Bridgeman Islands continues up to the central part of the Eastern Basin, whereas deep basin covered by thick sediments without any spreading structures develops in the northeastern part. This indicates that back-arc spreading along the axis of the Bransfield Basin has been taken place in the southwestern part of the Eastern Basin, not in the northeastern part. Many NW-SE trending faults perpendicular to the axis of the basin would be related with strike-slip movement of the Shackleton Fracture. Zone. Extensinal strutures like deep basin without any spreading structures in the northeastern part, normal faults and diapirs on both continental slopes of the Eastern Basin would be formed by extension as a consequence of the sinistral movement between Antarctic and the Scotia plates.