• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.541-547
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• 2013

It is important to establish water treatment technologies for drinking water because Korea belongs to water-stressed country. Leachate from recent incident of foot-and-mouth disease has become an opportunity to be aware of the need to manage water quality. Water purifiers are adopted to four or five steps of filtration process. Each steps are composed of a sediment filter, a pre-carbon filter, an UF or a RO membrane filter and a post-carbon filter. And additionally a ceramic filter can be used as a final stage. In this study, operational conditions in each steps are examined and characteristics of each filters are investigated. SEM analysis is used for filter surface and shape investigation using 6 commercial samples. Pore sizes of the sediment filter, the UF membrane filter, and the RO membrane filter are 30~47 ${\mu}m$, 0.005~0.5 ${\mu}m$, and 0.025~0.25 ${\mu}m$, respectively. Specific surface areas of activated carbons are ranged from 622 to 1,308 $m^2/g$.

• Journal of Environmental Impact Assessment
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• v.19 no.2
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• pp.107-116
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• 2010

In this research potential liquation of contaminants from surrounding soil to a reservoir in an island was studied to investigate the cause and route of contamination of Baengyeong-myeon reservoir. Soil of Baengyeong-myeon reservoir consists of $SiO_2$ and has a high iron content because of geological characteristics of its country rock. From the field investigation and simulation study it was found that highly accumulated carbon content in the reservoir sediment was incurred from ground water, which provides a good habitat for microbes. And the liquation, the cause of organics growth, occurs mainly on the bottom of the reservoir consisting marine clay layer once used as farmland. So dredging of the sediment of reservoir and replacing with valley soil is suggested to prevent continuous contamination of a reservoir in an island due to COD production.

• 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.

• The Journal of the Acoustical Society of Korea
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• v.21 no.2
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• pp.110-119
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• 2002

Acoustic characteristics of water sediment were experimentally studied in laboratory. Water saturated sand sediment less than the grain size of 0.5 mm diameter is uniformly distributed in an acryl box (100 mm×100mm×42mm) with material thickness 1 mm. Pores in the acryl box are modeled as the structure of cylindrical pore tubes (diameter 3 mm and length 42 mm) filled with water. Cylindrical pore tubes have porosities 0%, 5%, 11%, 18% and 26 % controlled by the tube numbers. Transmitted acoustic waves through sand sediment specimen are analyzed as the functions of porosity and frequency from 0.3 MHz to 4 MHz. Transmitted acoustic waves are mixed with the first-kind wave from whole specimen and the second-kind wane from cylindrical pore tubes. For the center frequency 1 MHz, the first kind wave is dominant but for the center frequency 2.25 MHz, the second kind wave is dominant. In the case of the first-kind wave, as the porosity increases, the transmission coefficient decreases and the sound speed decreases to the sound speed of water. As the frequency increases, the transmission coefficient decreases but the sound speed is almost constant. In the case of the second-kind wave, as the porosity increases, the transmission coefficient increases but the sound speed is almost constant. The transmission coefficient and the sound speed are almost constant as a function of frequency.

• 한국해양학회지
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• v.27 no.4
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• pp.277-289
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• 1992

Kyeonggi Bay, a macrotidal coastal embayment in the Yellow Sea coast of central korea, is fringed by vastly developed tidal flats. About 400 surface sediment samples were collected from the intertidal and subtidal zones of Kyeonggi Bay for a study of the sediment distribution pattern and the surface sediment characteristics of this environment. The kyeonggi Bay surface sediment becomes progressively finer in the shoreward direction, from offshore sand to shoreward silty sand and sandy silt. This shoreward-fining trend is repeated again on the tidal flat and, as a consequence, a grain-size break occurs near the low-water line which separates the intertidal area from the subtidal one. The intertidal and subtidal sediments differ from each other in textural characteristics such as mean grain size and skewness and this can be interpreted to result from differences in hydraulic energy and morphology between the two environments. The mineral and chemical compositions of the Kyeonggi Bay sediments are largely controlled by the sediment grain size. Smectite was nearly absent in the clay mineral assemblage of Kyeonggi Bay sediment. The contents of Co, Cu and Ni were high in the Banweol tidal flat, which suggests a continuous process of accumulation of these metals. the intertidal environment appears to respond rapidly to artificial coastal modifications, the effects of which should be taken into consideration when planning a dam construction or coastal reclamation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.541-547
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• 2017

In Yongwon channel, its natural flow of seawater is blocked by the construction of Busan Newport including the container berth. The channel was transformed into a narrow and long one, where it is possible that ships are only allowed to pass through the north-side channel of Gyeonmado located at the point of river mouth to Songjeongcheon. So it is considered that the changes in the terrain characteristics of Yongwon channel is likely to alter the circulation of sea water, thereby changing its water quality. Contaminants are accumulated from the sediment release. In this study, before and after dredging the sediment release test was performed. As a result, after the sediment dredging is performed, the reduction rate was higher at the same point. The results show that the water quality can be improved by dredging. Each group (A~C) reduction rate of the evaluation of the reduction rate of 4.64% T-N, 18.00%, 18.59%, respectively. T-P rate of 24.75% reduction, 24.17%, 44.08%, respectively. COD reduction rate was 18.57%, 19.76%, 38.08%, respectively. These results can be used as basic data for controlling the contamination by dredging in Yongwon channel.

• The Korean Journal of Food And Nutrition
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• v.29 no.1
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• pp.134-143
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• 2016

We evaluated the antioxidant properties of adzuki beans and the quality characteristics of sediment using various cultivation methods. There were significant differences in total polyphenol and flavonoid contents in beans grown using different methods of cultivation (p<0.05). Also, DPPH and ABTS radical-scavenging activities were significantly different depending on cultivation method (p<0.05). The sediment yield before drying of Chungju-pat, Hongeon, and Arari was 296.64~339.01, 271.36~282.24, and 268.21~292.32%, respectively, and the sediment yield after drying was 71.68~85.41, 77.90~85.19, and 74.15~78.65%, respectively. The L-value of Chungju-pat and Arari sediments revealed a significant difference given different cultivation methods (p<0.05), but Hongeon sediment did not show a significant difference. There was a significant difference in the a- and b-value of adzuki bean sediments cultivated using different methods (p<0.05). The particle size of Chungju-pat, Hongeon, and Arari sediments was 66.21~98.80, 61.62~97.07, and $82.96{\sim}106.71{\mu}m$, respectively, and all were significantly different depending on cultivation method (p<0.05). There were also significant differences in the water absorption index, water solubility index, and swelling power when different cultivation methods were used (p<0.05).

• The Korean Journal of Mycology
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• v.49 no.2
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• pp.183-197
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• 2021

Various freshwater ecosystems, such as streams, lakes and rivers, provide a dynamic habitat for fungi. In this study, we isolated several fungal strains from freshwater sediment and plant litter. The strains were identified using molecular phylogenetic analyses of rDNA and beta tubulin (TUB) sequences. Morphological characteristics of the fungi were also investigated using microscopy and culture characteristics of the fungi grown on several media. We identified seven species previously unrecorded in Korea, Nothophoma spiraeae, Westerdykella aquatica, W. aurantiaca, W. dispersa, Chrysosporium sanyaense, C.pseudomerdarium and Taeniolella phialosperma.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.293-302
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• 2015

This study investigated sediment oxygen consumption rates and geochemical characteristics of sediment in hypoxic area of the Gamak Bay based on the chamber experiments and geochemical analyses. The organic carbon contents of surface sediment in the Gamak Bay showed that the inner bay area has higher organic carbon content than those of the outer bay. They toward the outer bay, contents dropped off. The vertical profiles of calcium carbonate ($CaCO_3$) content at piston core sediment assumed that the hypoxia have been frequently occurred during past century in the northern inner bay. The benthic chamber experiments were conducted in February, May, August and November 2010, 2011 in the hypoxic area of the Gamak Bay. In the sediment incubation experiment with chamber at site C3 in the northern inner bay and site C17 in the southern outer bay, the sediment oxygen consumption rate ranged from $3.98mmol\;m^{-2}d^{-1}$ to $12.43mmol\;m^{-2}d^{-1}$ and $3.28mmol\;m^{-2}d^{-1}$ to $8.18mmol\;m^{-2}d^{-1}$, respectively. When the oxygen was completely depleted, the toxic hydrogen sulfide was released with $1.38mmol\;m^{-2}d^{-1}$ and $1.3mmol\;m^{-2}d^{-1}$, respectively.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.589-593
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• 2005

A laboratory study on the adsorption of nitrate in polluted coastal water using various materials including several types of dredged sediments(ST) and yellow c1ays(YC), which are activated by heat(HT), bioleaching for heavy metal removal(BL) and neutralization(NR) was performed. The equilibrium time of the adsorption for the sediment bioleached and treated by heat(BL-HT-ST) was only 17min which was faster than the sediment bioleached, neutralized and treated by heat(BL-NR-HT-S) (25min) or the sediment treated by the bioleaching process(BL -ST)(27min), but longer equilibrium times for yellow c1ay(YC) or heat treated yellow day(HT- YC) were required. The adsorption processes of nitrate in sea water for tested material could be described by Freundlich isotherm, but were significantly affected by surface characteristics of the materials. The adsorption capacities for raw sediment and heat treated sediment were 2.12 and 2.19mg NO3-N/g, respectively, which were higher than others, indicating that the sediment activated by heat could be used as a material for the improvement of nearshore water quality.