• Journal of Korean Society of Environmental Engineers
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• v.28 no.4
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• pp.438-446
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• 2006

A lab-scale batch test was conducted to develop capping materials to reduce the sediment phosphorus in the stagnant water zone of Gyeongancheon in Paldang Lake. The mean grain size(Mz) of sediment in the investigated area was 7.7 ${\phi}$, which is very fine, and the contents of organic carbon($C_{org}$) was 2.4%, which is very high. For the phosphorous release experiment to select the optimal capping material, sand layer, powder-gypsum($CaSO_4{\cdot}2H_2O$), granule-gypsum, complex layer(gypsum+sand) and the control were compared and evaluated in the 150 L reactor for 45 days. In case of the capping with the sand, it was found that the phosphorous from the sediment could be reduced by around 50%. However, it was found that this caused the reduction of the dissolved oxygen in the water column(by less than 3 mg/L) due to the resuspension of sediment and the organic matter decomposition that comes from the generation of $CH_4$ gas in the 1 cm of the sand layer. Therefore, it is likely that the sand layer has to be thickener in case of the sand capping. Powder-gypsum and granule-Gypsum reduced phosphorous release by more than 80%. However, the concentration of ${SO_4}^{2-}$ in the water column increased, making it difficult to apply it to the drinking water protection zone. We developed Fe-Gypsum and $SiO_2$-gypsum materials to reduce the solubility of ${SO_4}^{2-}$. Powder-Gypsum creates the interception film that does not have any aperture on the sediment layer when it is combined with the water. However phosphorous release caused by the generation of $CH_4$ gas may happen at a time when the gypsum layer has the crack. Capping through the complex layer(granule-Gypsum+sand(1 cm)) found to be suitable for the drinking water protection zone because it was effective to prevent phosphorus release. Moreover, this leads to the lower solubility from the concentration of ${SO_4}^{2-}$ into the water column than the powder-Gypsum and granule-Gypsum. The addition of gypsum($CaSO_4{\cdot}2H_2O$) into the sediment can reduce the progress of methanogensis because fast early diagenesis and sufficient supply of ${SO_4}^{2-}$ to the sediment, stimulate the SRB(sulfate reducing bacteria) highly.

• The Korean Journal of Quaternary Research
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• v.9 no.1
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• pp.19-32
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• 1995

한반도 서해 만경강-동진강 하구역 조간대 퇴적층의 수직층서 퇴적상 변화를 분석 하여 퇴적과정을 기초해양환경의 관점에서 해석하였다. 본 연구해역 저 조선의 퇴적층은 사 질함량이 우세한 반면 방조제와 인접한 만조선의 퇴적층은 실트질이 우세하였고 상층과 하 층의 퇴적물이 뚜렷하게 구분되었다. 사질퇴적층의 내부퇴적구조는 괴상구조, 평행층리 및 사층리 구조등이 우세하며 니질퇴적층에서는 모래/니질 교호엽리구조가 우세하다. 본 연구 의 결과 만경강-동진강 조간대 퇴적층서는 인근의 방조제 축조에 다른 퇴적환경 변화에 크 게 영향받은 것으로 해석된다, 즉 방조제축소 이전 고에너지의 퇴적환경에서 집적되었던 사 질퇴적층이 방조제축조 이후에는 저에너지 환경조건에서 집적된 니질퇴적물로 피복된 것으 로 해석된다.

• Journal of the Korean Geophysical Society
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• v.5 no.1
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• pp.51-62
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• 2002

Investigation of underwater sedimentary layers has been carried out with GPR(Ground Penetration Radar) survey. FPR survey has been proved to be very satisfactory since the target area has shallow water depth of about 2.5 m, is a lake with no water flow, and the thickness of mud layer, which is a main survey target, is relatively thin. The results clearly showed the underwater sedimentary layers, which includes mud, sand, gravel and basement layer. Specially, the distribution and total amount of mud layers from the survey results can be used as a basic data for the dredging of mud layer in the area.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.317-317
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• 2011

맨홀 및 관로에 퇴적되는 유사는 우수관거의 통수능을 감소기키고 우수관거 시스템의 효율을 저하시켜, 맨홀에서 역류를 발생시켜 저지대 침수의 한 원인인 되고 있다. 또한 관거내에서 유수가 일정한 유속을 확보하지 못하면 오염물이 침전되고, 관거내 유하시간이 길어져 침전물 부패로 인한 황화물질 및 악취 등이 발생할 수 있다. 따라서 우수 및 하수관거 시스템에서 유사와 관련된 주된 연구는 관거내의 유사거동 특성을 규명하고자 하는 것이었다. 그러나 맨홀과 관련하여서는 맨홀내의 오염물 지체시간 및 확산 특성분석이 전부였고, 유사의 퇴적 및 배출 등과 관련된 거동특성 연구는 매우 미흡한 실정이다. 본 연구에서는 유입관과 유출관이 $90^{\circ}$로 접합된 맨홀을 대상으로 수리실험을 실시하고, 맨홀형태(사각형, 원형), 유사유입형태(연속주입, 일정기간주입), 유사종류(주문진표준사, 모래), 유사유입량 및 맨홀내부형상 변화에 따른 맨홀내 유사퇴적량을 확인하였다. 실험결과 그림 1과 같이 $90^{\circ}$ 접합맨홀에서는 유사유입형태와 무관하게 유입유사량이 증가할수록 퇴적량 또한 증가하였다. 그러나 유사퇴적량은 사각형맨홀보다 원형맨홀에서 적었다. 이는 관거가 $90^{\circ}$로 접합된 맨홀내에서의 유사거동 양상은 우선 유입되는 유사가 맨홀바닦에 퇴적되고 와류에 의해 부유되는 유사가 유출관을 통해 배출되는데 사각형맨홀에 비하여 원형맨홀에서 와류가 더 크게 형성되기 때문인 것으로 판단된다. 유사가 일정기간주입되는 경우 원형맨홀 내부에 퇴적되는 유사량은 거의 없었다. 사각형맨홀내부에 벤칭을 설치한 경우 설치전과 비교하여 퇴적량은 50%이상 저감되었고, 일정기간주입시에는 벤칭 설치 후 유사퇴적량은 거의 없었다. 유입유사가 모래인 경우 맨홀내 퇴적량은 주문진표준사와 비교하여 증가하였다. 모래는 주문진 표준사와 비교하여 중량이 크다. 따라서 같은 흐름조건에서 주문진표준사와 비교하여 부유되는 유사량이 적고, 배출되는 유사량 또한 적었다. 유량과 관거유속이 동일한 조건에서 유출관과 유입관이 일직선상으로 연결된 중간맨홀내부에 퇴적된 주문진표준사의량과 비교하여 $90^{\circ}$ 접합맨홀의 퇴적량이 상대적으로 적었다. 이 또한 앞서 기술한 와류의 영향으로 판단된다. 일반적으로 $90^{\circ}$접합맨홀내부에서 발생하는 와류가 중간맨홀보다 크고, 이로 인해 에너지손실은 커지지만 유사거동과 관련하여서는 와류가 크게 발생하는 맨홀조건에서 퇴적량이 적음을 실험적으로 확인하였다.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.81-91
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• 2020

This study was conducted to find the faunal composition and distribution patterns of macrobenthos where the sand tidal flat around barrier island at Nakdong River estuary in May, 2016 and 2017. The number of species ranged from 31 to 39, and density was from 789 to 1,644 ind.m^-2 during the study period in the three tidal flats. The number of species and density were the highest in the tidal flat of Shinja-do and Jinwoo-do, respectively. The dominant species were Gammaridae unid. in amphipods of crustacea, Scoletoma heteropoda, Scoloplos armiger, Heteromastus filiformis, Prionospio japonica in polychaeta and Batillaria cumingii, Laternula marilina in mollusks from the three tidal flats. The proportion of carnivores such as crustacea and mollusks was higher in the upper part of the tidal flat, and polychaetes of deposit feeders, dominated in the middle and lower tidal flat. Overall, the intertidal macrobenthic communities in the study area showed a high proportion of carnivores. However, the sites where the mud content is high such as muddy sand sites, they showed a higher proportion of surface deposit feeders belonging to tube-builders which contribute to sediment stability. From this study, it seemed that the macrobenthic fauna of the sandy tidal flat at the Nakdong River estuary showed a similar fauna composition and zonal distribution patterns from those in other sandy tidal flats in Korea.

• Journal of Aquaculture
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• v.15 no.1
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• pp.1-6
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• 2002

Hydrological factors prevailing in the Namdae stream were as follows : temperature = -0.2~$26.8^{\circ}C$, salinity = 0.50~3.21$\textperthousand$, DO = 5.21~8.13 ppm, $PO_{4}-P$ = ND~1.37 ppm, $NO_{2-}$ = 0.10~0.81 ppm, COD = 1.53~2.82 ppm, $H_2 S$ = ND~0.0012 ppm and IL = 0.85~1.36 %. Sediment was typical, gravelly sand or sand with very good sorting value ranging from 0.53 to 1.77$\varphi$. Population density of the clam C. japonica ranged from 2 to 464/$m^2$. The clams were divided into four size classes, based on shell length of small (0~10 mm), medium (10~20 mm), large (20~30 mm) and largest (>30 mm), and were encountered at the frequency of 3.2, 50.4, 43.3 and 3.1 %, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.472-479
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• 2006

In this research, speciation of phosphorus in sediment and overlying water dependent upon pH and ORP(Oxidation Reduction Potential) was studied. Three possible conditions were simulated: open system with circulation, closed system with stratification and closed system with sand capping on the sediment. Phosphorus release rate from sediment was increased for both open system and closed system if pH was less than 6.0. Phosphorus concentration for closed system was increased from 0.9 mg/L to 0.51 mg/L, and stabilized at 0.34 mg/L if anaerobic conditions were maintained in the overlying water. When sand capping was implemented, phosphorus concentrations of overlying water were maintained less than those of closed system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.2
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• pp.3-10
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• 2000

The main purpose of this study were to estimate the benthic fluxes of dissolved inorganic nitrogen (DIN) from the sediment and denitrification rates in tidal flats of the Keum river estuary. Sediment specimens were collected by a core sampler from three stations along the Keum river estuary in April, August and December, 1999. The sediments were composed of 1.18 %, 29.34 % and 69.49 % of gravel and sand, sand and silt, respectively. The mean ignition loss of the sediment was found 6.7 % and its Oxidation Reduction Potential (ORP) was measured -12 mV. The total hydrogen sulfides was determined about 0.26 mg/gㆍdry. The estimated outflux of ammonium was found 11.2 m mole N/m²ㆍday from the sediment, whereas -1.09 m mole N/m²ㆍday of influx was obtained for nitrate and nitrite through the incubation experiment of sediment cores. Total DIN flux was 10.2 m mole N/m²ㆍday outflux from the sediment. From the incubation experiments executed with the flux studies, mean denitrification rate was found 30.6 m mole N₂/m²ㆍday measured by the direct assay of N₂ production technique. On the basis that DIN flux and denitrification rate in sediment of tidal flat of the Keum river estuary are may be effects to control the algal biomass in the coastal environment, it seems inevitable to pay more attention to investigate the flux of DIN and denitrification rate in tidal flat of the Keum river estuary.

• Journal of the Korean earth science society
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• v.33 no.6
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• pp.497-509
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• 2012

The Gochanggun Kwangseungri macro-tide open-coast beach, located in the southwestern coast of Korea, was investigated in terms of the seasonal variations of surface sediment facies and sedimentary environment. Surface sediments of 45 sites in four seasons (May 2006 - February 2007) were sampled along three survey lines (15 sites in each survey line). The surface sediments of the Kwangseungri Beach are mainly composed of fine-grained sands, and its mean grain size is the coarsest in winter. Mud facies partly exists in summer, whereas it is nearly absent in winter. The spatial distribution of surface sediments shows a coast-parallel band of fine and medium sands during spring, fall, and winter. In the northern part, the study area is dominated by fine sands during summer, whereas by coarse sands during winter. These results can be interpreted that tide is more effective than wave on the surface sediment distribution of the Kwangseungri Beach during the summer season.

• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.257-266
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• 2018

East China Sea (ECS) is known to be supplied with large amounts of sediments form Huanghe, Changjiang and various rivers in Korea. Many studies have been conducted to identify the effects of rivers and deposition process of ECS, but no consensus has been reached. In this study, clay minerals, rare earth elements (REEs) and grain size were analyzed to study the provenance and sedimentation environment of core 99MAP-P63 in ECS. Clay mineral contents of 99MAP-P63 are abundant in order of illite, chlorite, kaolinite, and smectite. The provenance of 99MAP-P63 sediments using clay minerals is interpreted as the Changjiang regardless of depth. As a result of REEs analysis, 99MAP-P63 sediments are very similar to Chinese rivers sediments. Therefore, the provenance of 99MAP-P63 is Changjiang, and the influence of Korean river seems to be insignificant. 99MAP-P63 sediments are generally classified as sandy silt, but the top of the core is divided into sand with a sand contents of 85 %. Compared with surrounding cores, sandy silt sediments arecorresponded to the low stand stage when sea-level was low, and the sediments were thought to have been supplied directly through the paleo-Changjiang. Sandy sediments in uppermost of core are corresponded to transgressive stage. Although distance from estuary was increased due to sea-level rise, it was possible to supply coarse sediments due to high bottom stress, and the paleo-Changjiang sediments deposited in study area were re-deposited.