• Journal of Korean Society of Water and Wastewater
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• v.24 no.3
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• pp.341-349
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• 2010

It is well known that manganese is hard to oxidize under neutral pH condition in the atmosphere while iron can be easily oxidized to insoluble iron oxide. The purpose of this study is to identify removal mechanism of manganese in the D water treatment plant where is treating bank filtered water in aeration and rapid sand filtration. Average concentration of iron and manganese in bank filtered water were 5.9 mg/L and 3.6 mg/L in 2008, respectively. However, their concentration in rapid sand filtrate were only 0.11 mg/L and 0.03 mg/L, respectively. Most of the sand was coated with black colored manganese oxide except surface layer. According to EDX analysis of sand which was collected in different depth of sand filter, the content of i ron in the upper part sand was relatively higher than that in the lower part. while manganese content increased with a depth. The presence of iron and manganese oxidizing bacteria have been identified in sand of rapid sand filtration. It is supposed that these bacteria contributed some to remove iron and manganese in rapid sand filter. In conclusion, manganese has been simultaneously removed by physicochemical reaction and biological reaction. However, it is considered that the former reaction is dominant than the latter. That is, Mn(II) ion is rapidly adsorbed on ${\gamma}$-FeOOH which is intermediate iron oxidant and then adsorbed Mn(II) ion is oxidized to insoluble manganese oxide. In addition, manganese oxidation is accelerated by autocatalytic reaction of manganese oxide. The iron and manganese oxides deposited on the surface of the sand and then are aged with coating sand surface.

• The Korean Journal of Petroleum Geology
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• v.10 no.1_2 s.11
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• pp.10-17
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• 2004

The Doowoo-ri tidal flat in the southwestern Korean coast is a typical open-coast tidal flat which has no barriers in the offshore such as barrier island and sand bars. The difference of induced wave energy with seasons is affected directly on the distribution of surface sediment and the formation of sedimentary structures because the sedimentation by wind wave is relatively much important element in this open-coast tidal flat. This open-coast tidal flat can be classified into tidal beach, intertidal flat and lower mudflat according to the pattern of geomorphology and sediment type. The intertidal flat can be again divided into 3 types: sand flat, mixed flat and mud flat based on the primary sedimentary structure and sand/mud ratio. Doowoori tidal flat shows a seasonal change in the surface sedimentary facies based on sediment composition and primary sedimentary structure. The change is closely related to the direction and magnitude of monsoon wind and also to storm frequency. In winter and spring, when northwesterly wind is most dominant and strong and also storms are common, sand-flat facies is largely distributed on the intertidal flat, whereas mud-flat facies is most dominant during summer when weak southeasterly wind is common. In the fall season, mixed-flat facies is dominant on the flat. The Doowoori intertidal flat is covered by mud sediment which is ca. 20 cm in thickness in summer season. In winter season, surface sediment is changed from mud to sand because the summer mud is mostly eroded by strong wave action. Can-core peels in the intertidal flat show that parallel laminated mud or sand/mud and climbing ripple cross-laminated sandy silt are dominant on the upper intertidal flat $(0-1.3 {\cal}km)$ during summer season. On the other hand, on lower intertidal flat $(1.7-2.3 {\cal}km)$, dominant sedimentary facies is homogeneous mud. In winter, it is changed into parallel laminated and ripple cross-laminated sand facies.

• 한국해양학회지
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• v.27 no.1
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• pp.66-77
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• 1992

Tidal sand ridges and sand waves are well developed in the Yellow Sea off Tae-An Peninsula, Korea. Their transport directions were inferred based on high resolution seismic profiles, surficial sediment characteristics and tidal regime. Tidal sand ridges are asymmetric, with long axes parallel to or slightly oblique to the dominant NE-SW tidal current direction. They show steep south and/or southeast flanks, which are in concordance with the apparent direction of internal cross-bedding in the south. Holocene sediments occur in accordance with distributional patterns of tidal sand ridges. These features indicate that Holocene active tidal sand ridges move toward the open sea in southeast, south and southwest direction. Sand waves which are distributed in flat sea floor with depth of about 40-60m show also asymmetric forms with a steep east-to-northeast face. Surficial sediments in the sand wave field are characterized by well sorted fine sands compared with poorly sorted adjacent areas. The sand waves appear to undergo easterly or northeasterly landward movement.

• Journal of The Geomorphological Association of Korea
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• v.19 no.1
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• pp.29-40
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• 2012

The sand dunes at the lower reach of the Duman river indicate that their distribution patterns and directions conform to the dominant northwestern winter wind. On the riverbed of the Duman river at the surroundings of sand dunes form sandy point bars and mid-stream islands. The geomorphic processes of sand dunes can be classified into two types according to the depositional environments via analyses of the sand grain size and stratigraphic profiles. First, the sand dunes of Hoelyongbong, Kyeongshin-Wonjeong, and the riverside areas of the Duman river, have formed by alluvium of the Duman river which deposits and accumulates on the riverbed, then being wind blown to the nearby sand bars, terraces and higher eroded hills. The second type is the active sand dune of the Bangcheon-Nodongja District which develops similarly as to the formation of the first type, but the fixed sand dunes of the district seem to have formed in the underwater condition.

• Journal of Wetlands Research
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• v.7 no.2
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• pp.69-88
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• 2005

Distribution of benthic macrofauna was surveyed in the subtidal area and on the sand flat of Sindu-ri coast during July 2002. A total of 134 species, 3,511 individuals and 388g biomass of macrobenthos were sampled inclusively from the study sites. 109 species with a mean density of $1,298ind./m^2$ and biomass of $69.4g/m^2$ were collected from 10 stations established in the subtidal area. Polychaetes were represented as a dominant faunal group of the subtidal area in both species richness and density with values of 54 species and $813ind./m^2$. Cluster analysis based on the faunal composition showed that the subtidal area could be divided into four stational groups according to sedimentary characteristics: Cirrophorus armatus - Lumbrineris longifolia association on the mud sediment with pebbles near aqua-farms; Aonides oxycephala association on the rocky bed; Scoloplos armiger - Grandifoxus cuspis association on the sand-dominated sediment along the lowest low water; a association with higher evenness on the sand-dominated sediment in the depth. Although having characteristics of high value in species richness, density and species diversity, the macrobenthic association around the farming area was dominated by the opportunistic species such as Lumbrineris longifolia and Tharyx sp. Natural community represented by S. armiger and G. cuspis was developed in most sand-dominated areas. 50 species were sampled with a mean density of $2,443ind./m^2$ and biomass of $381.3g/m^2$ from eight+ stations along two transects on Sindu-ri sand flat. Mollusks were represented as a dominant faunal group of the sand flat in species richness, density and biomass with values of 20 species, $1,345ind./m^2$ and $350.4g/m^2$, respectively. Umbonium thomasi, Veneridae sp., Mandibulophoxus mai, Armandia lanceolata, Eohaustorius spinigerus, Urothoe convexa were dominant species and these species accounted for over 83% of total individuals. There were three distinct zones of macrobenthos on Sindu-ri sand flat according to the extent of exposure time. The upper zone was dominated by Scopimera globosa, the middle zone was characterized by M. mai, and the lower zone was dominated by E. spinigerus. Sindu-ri coastal area was considered as a healthy habitat for macrobenthos, except for around the farming area. It was considered that Sindu-ri coastal area including the sand flat connected to the sand dune of natural monument was a valuable habitat as a protected site in having no pollution source and no artificial structure.

• Journal of the Korean Geotechnical Society
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• v.31 no.3
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• pp.27-38
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• 2015

Triaxial tests on sand-silt mixture specimens under low and high confining pressures were performed to understand their shear behaviors. The fines content in the mixture is lower than the threshold value. A series of tests under different conditions including fines contents (0%, 9.8%, 14.7%, 19.6%), density of specimen (controlled by different compaction energies of $E_c=22kJ/m^3$, $E_c=504kJ/m^3$), confining pressure (100 kPa, 1 MPa, 3 MPa, 5 MPa) were performed to investigate influences of these factors. Based on the test results, the threshold fines content, where the dominant structure of mixture changes from sand-matrix to fines-matrix, decreases with the increase of confining pressure. Under very high confining pressures, as a result of sand particle crushing, the behavior of the dense specimen is similar to that of the loose specimen which shows hardening, compression behavior, and shear strength increases with increase of fines content. In conclusion, silt is granular material like sand, and its influence on shear behavior of sand-silt mixture is very different from that of plastic fines on sand-fines mixture.

• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.135-141
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• 2016

This study investigated changes of hydrology, soil characteristics, riparian vegetation communities, and geomorphology in sandbars before and after sand-mining to determine the effect of sand-mining at upstream of Guemgang and Bochungcheon streams in Korea. Sand-mining events affected the mining area. They supplied organic matters and nutrients during flood. Sediment deposition caused soil texture change and expansion of vegetation area. However, riverbeds were stabilized after the disturbance. According to the analyses of aerial photographs, the vegetation area was significantly expanded in both dam-regulated streams and dam-unregulated streams after sand-mining. Willow shrubs advanced in disturbed area at an average of 10 years after sand-mining. It took willows trees 10.6 years to become dominant communities. Therefore, it took a total of 20.6 years for new riparian forest to form in sandbar after sand-mining. Our results confirmed that stream flow condition were dependent on vegetation recruitment in dam-regulated streams and dam-unregulated streams. For willow recruitment in unregulated streams, calculation of water level below dimensionless bed shear stress is important because low water level variation is a limiting factor of vegetation recruitment.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.185-204
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• 2024

This study was conducted for evaluation the geological, physical, and chemical properties of domestic sand by analyzing about 4,800 quality data of natural sand from river and land area surveyed until 2023 through the aggregate resource survey conducted by the Ministry of Land, Infrastructure and Transport. The average depth of the Quaternary unconsolidated sedimentary layer in Korea, which includes a sand layer, is about 10m (maximum depth 66m). The thickness of the sand layer within the sedimentary layer is most dominant in the range of 0.5m to 4.0m. This accounts for about 70% of the entire sand layer. In the sand layer, the ratio of sand, gravel, and clay is 60:20:10. Regardless of the provenance or geology, the sand is mainly composed of quartz, plagioclase, and K-feldspar, and the minor minerals are muscovite, biotite, chlorite, magnetite, epidote. The sand includes in 45~75% of quartz, 5~20% of plagioclase and K-feldspar, each other. And other minor minerals are included in 10%. The average grain size of sand is 0.5mm to 1.0mm, which accounts for 44% of sand samples. The water absorption rate and soundness are estimated to be suitable for aggregate quality standard in almost all sand, and the absolute dry density is suitable for 66%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.573-581
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• 2016

Bacterial decarboxylation of amino acids in food leads to the production of biogenic amines, which can cause reactions in human that include headaches, nausea, palpitations, chills, and severe respiratory distress. The amine putrescine is an especially effective inhibitor of metabolizing enzymes and amplifies histamine intoxication and tyramine poisoning. Using an L-ornithine decarboxylating medium, we isolated 14 putrescine-producing bacteria from sand lance, Ammodytes personatus, sauces. The isolates were identified, using an API kit and 16S rRNA analysis, as Lysinibacillus fusiformis (1 strain), Lysinibacillus xylanilyticus (6 strains), Lysinibacillus macroides (1 strain), Lysinibacillus sphaericus (3 strains), Bacillus fusiformis (1 strain), Paenibacillus favisporus (1 strain), and Staphylococcus caprae (1 strain). These strains produced between 1.66 to 236.97 μg/mL of putrescine after 48 h incubation. Lysinibacillus spp. were the dominant putrescine-producing bacteria in sand lance sauces, which produced 236.97 μg/mL of putrescine from a culture broth containing 0.5% L-ornithine. This is the first report on the isolation and identification of putrescine-producing bacteria from sand lance sauces.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.792-799
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• 2016

We isolated seven tryptamine-producing bacteria from commercial salted and fermented sand lance (Ammodytes personatus) sauces using an L-tryptophan decarboxylating medium. These tryptamine-producing bacteria, identified using an API kit and 16S rRNA analysis, included Lysinibacillus xylanilyticus (one strain), Lysinibacillus fusiformis (four strains), and Staphylococcus epidermidis (two strains). Lysinibacillus spp. produced the highest levels of tryptamine in culture broth containing 0.5% L-tryptophan, compared with 1.0% and 2.0% preparations. After 72 h of incubation, Staphylococcus epidermidis produced the highest levels of tryptamine ($60.50{\mu}g/mL$ and $664.86{\mu}g/mL$) in culture broth containing 2.0% L-tryptophan. While Lysinibacillus spp. comprised the dominant tryptamine-producing bacteria in sand lance sauces, Staphylococcus epidermidis also showed high tryptamine-producing activity. This is the first report on the isolation and identification of tryptamine-producing bacteria in sand lance sauces.