• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제26권1호
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• pp.59-73
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• 1998

Sediment samples from five stations at the Shihwa Lake sewage outfall, west cost of Korea, were collected to evaluate the effect of the outfall on benthic foraminifers. Heavy metal (Cu and Zn) polluted the eastern part of the Shihwa Lake, adjacent to the Shihwa-Banwol Industrial Complexes, shows barren or nearly barren of benthic foraminifers, and the lowest number of species both at the core top and downcore. Excepting for the barren zone, pyritized benthic foraminifers abundantly occur both at the surface and downcore sediments in the western part of the Shihwa Lake, suggesting that foraminiferal disease by anoxic bacteria. Recent intrusion of pollutants form the Shihwa-Banwol Industrial Complexes and adjacent six major streams severely polluted the Shihwa Lake as shown by the low abundance (number/10 g) of benthic foraminifers, low number of Ammonia beccarii, low species diversity, and absence of both Elphidium spp. and ostracodes at the surface sediments compared of both downcore. Except the barren zone, both pyritized and non-pyritized Ammonia beccarii occur dominantly in the surface sediments and downcore. Elphidium spp. (either pyritized or non-phyritized) do not occur in the surface sediments of whole stations. However, they occur from the entire downcore sediments except in the eastern part of Shihwa Lake. Arenaceous foraminifers do not inhabit in the heavily polluted areas as evidenced by the occurrence of relatively deep core depth (11-15 cm). Ostracodes occur at the downcore sediments, but they do not occur at the surface sediments. Ostracodes also do not occur at the heavily polluted areas in the eastern part of the Shihwa Lake both at the surface and downcore sediments, indicating that the abundance of ostracodes also can be used for a pollution indicator.

• Environmental Engineering Research
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• 제18권2호
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• pp.71-75
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• 2013

This study is to evaluate the effects of the separation wall on the sediment quality and quantity in a combined sewer, by surveying the sewer overflow and sediments during a rainfall. Since the separation wall installed in the combined sewer separates the rainfall and the sewage, the flow rate of the sewage is increased, and the amount of the sediment deposited on the sewer is decreased. One sampling point was the outfall of Daesacheon with a separation wall, and the other was the outfall of Gwaryecheon without a separation wall, in Daejeon metropolitan city. The maximum control of the biochemical oxygen demand (BOD) overflow load was more than 38% in the Daesacheon point with the separation wall, during a rainfall of 0.11 mm/hr. The maximum control of the BOD overflow load was 24% in Gwaryecheon without a separation wall, during a rainfall of 1.0 mm/hr. According to the survey results of the sediment in the sewer, the discharged sediment deposited on the sewer in Gwaryecheon point was about 23% to 28% of the total suspended solid during the rainfall. In addition, the average velocity of sewage in the presence of sediment was about 0.30 m/s, and if the separation wall is installed, it was expected to be about 1.01 m/s, that is 3.4 times more than the same conditions, resulting in the reduction of the sediment deposit.

• Membrane and Water Treatment
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• 제10권1호
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• pp.75-82
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• 2019

In a highly urbanized area, land availability is limited for the installation of space consuming stormwater systems for best management practices (BMPs), leading to the consideration of underground stormwater treatment devices connected to the stormwater pipe system. The configuration of a stormwater pipe network determines the hydrological and pollutant transport characteristics of the stormwater discharged through the pipe network, and thus should be an important design consideration for effective management of stormwater quantity and quality. This article presents a multi-objective optimization approach for designing a stormwater pipe network with on-line stormwater treatment devices to achieve an optimal trade-off between the total installation cost and the annual removal efficiency of total suspended solids (TSS). The Non-dominated Sorted Genetic Algorithm-II (NSGA-II) was adapted to solve the multi-objective optimization problem. The study site used to demonstrate the developed approach was a commercial area that has an existing pipe network with eight outfalls into an adjacent stream in Yongin City, South Korea. The stormwater management model (SWMM) was calibrated based on the data obtained from a subcatchment within the study area and was further used to simulate the flow rates and TSS discharge rates through a given pipe network for the entire study area. In the simulation, an underground stormwater treatment device was assumed to be installed at each outfall and sized proportional to the average flow rate at the outfall. The total installation cost for the pipes and underground devices was estimated based on empirical formulas using the flow rates and TSS discharge rates simulated by the SWMM. In the demonstration example, the installation cost could be reduced by up to 9% while the annual TSS removal efficiency could be increased by 4% compared to the original pipe network configuration. The annual TSS removal efficiency was relatively insensitive to the total installation cost in the Pareto-optimal solutions of the pipe network design. The results suggested that the installation cost of the pipes and stormwater treatment devices can be substantially reduced without significantly compromising the pollutant removal efficiency when the pipe network is optimally designed.

• 상하수도학회지
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• 제8권3호
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• pp.41-50
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• 1994

The depth of sewers in residential complexes was determined to prevent the separated sewers from misconnection between storm sewer and sanitary sewer, and from the submersion of the basement by minimizing the phenomenon of backwater when it rains. In residential complexes, main causes of the submersion were the misconnection of sewers, rising of the backwater level at outfall in sewer system, poor maintenance of sewers, and lacking in their cross section. Minimum depth of sewers should be over 1.2~1.5m. According to the economic analysis, the depth of 1.5m~3.0m was appropriate for minimizing the submersion of basements and for making the disposal of domestic wastewater more easily.

• 한국항만학회지
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• 제11권2호
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• pp.231-240
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• 1997

미국에서는 오랜 전부터 1차 처리된 폐수를 해양배출구를 통하여 심해저로 흘러보내어 보다 효율적인 폐수처리에 기여하고 있다. 해저의 경사 때문에 연안의 폐수처리장에서 긴 관을 통해 심해저로 다공배출구를 연결시키고 있다. 그러나, 심해저확산배출구를 통해 흘러 나와 형성된 플롬이 근접한 연안에 간접적으로는 인간의 건강에 해를 줄 수 있다는 보고 때문에 바다의 물리적인 조건을 세심하게 고려한 심해저 확산배출구의 적절한 수심에서의 배치가 요구되고 있다 .우리나라의 연안역에서도 보다 효율적이고 신뢰할 수 있는 폐수처리를 위해 해양배출에 대한 고려를 하여야 할 것이다. 플롬의 거동을 예측하기 위해 일련의 플롬 동역학에 대한 연구에서는 여러 가지 모델이 사용되어 왔으나 대부분의 경우 플롬거동의 계산치가 현실과는 동떨어져 있다. 따라서 본 연구에서는 실제 배출특성과 해양의 조건을 시뮬레이션 하기 위한 플롬모델의 적용에서 개선방안을 제시하고자 하였다. 플롬모델에서 파랑과 흐름과 같은 실질적인 해상조건을 반영한 입력 파라메타를 도입하여야 하는 것이다. 이 논문에서는 최근의 마말라 만 연구에서 선택한 특정 모델의 입력 변수 중에 장파는 고려하지 않고 해류만을 고려한데서 오는 단점을 보완하여 선행파이론에 기초한 장파와 흐름이 공존함으로써 야기되는 해저로부터의 플룸 상승과 초기 희석 계산을 수행하였다. 실제적으로 해저에서 플룸의 형상이 해수뿐만 아니라 장파에 의해서 크게 영향을 받는다는 것을 염료를 넣어 플룸을 사진촬영함으로써 증명하였다. 앞으로의 연구에서는 장파와 같은 현실적인 인자를 세심하게 고려함으로써 계산 결과를 더욱 현실 값에 접근시킬 수 있게 되었다. 물론, 장파와 같은 인자를 도입함으로써 야기되는 물리학적인 한계점은 관련된 가정을 통해 어느 정도 보완이 되었지만 그러한 한계점은 향후 3차원적인 플룸 역학을 다룸으로써 보강차원의 실증적 연구자 더 필요하다고 하겠다. 미국환경보전국에서 승인한 개량플룸모델 중에서 RSB 및 UM모델을 플룸거동을 계시하는데 사용하였으며, 장주기파의 조건하에서 계산된 값을 플룸의 상승 및 초기회석의 관점에서 비교하였다.

• Water Engineering Research
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• 제3권2호
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• pp.93-111
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• 2002

In this paper, mixing characteristics and dilution of the merging buoyant discharges from array of multiple jets has been extensively studied in the hydraulic model experiments. New equations for dilution, which include the merging effects correctly, were derived. Experiments were constructed in a 20-m long, 4.9-m wide and 0.6-m deep flume, and the model diffuser was manufactured to indicate the typical characteristics of the existing ocean wastewater outfall in South Korea. Buoyant discharge from the diffuser was reproduced using heated water. Water temperature was measured using CC-Type thermocouple sensors, which were connected to a 40-channel data logger. Experimental results show that merging between ports in a particular riser is dependent upon the discharge densimetric Froude number, whereas merging between two ports which are facing each other at 90$\circ$ at the adjacent risers is dependent upon the discharge densimetric Froude number and distance from the port and port spacing. Centerline dilution increase with distance from the port outlet until two plumes has merged. However, after merging occurs, increase of the centerline dilution almost stops. Further distance from the position where merging occurs, centerline dilution increases again.

• 한국수자원학회논문집
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• 제33권2호
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• pp.207-217
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• 2000

밀도성층화된 흐름 수역으로 방류되는 부력제트에 의한 초기확산을 해석하기 위하여 수치모형을 적용하였다. 수치모형은 제트적분모형으로서 흐름수역의 원역에서의 대표적 특성으로 밝혀진 쌍와흐름특성을 모형에 반영한 Gaussian-vortex모형이다. 수치모형의 현장 적용성을 검토하기 위하여 수표면에서의 초기희석에 대한 관측이 수행된 6개의 해양방류관에 수치모형을 적용하였다. 현장관측자료에 대한 수치모형의 적용결과, 개발된 수치모형이 하수확산관에 의해 해양으로 방류되는 오염물질의 초기 확산해석에 활용될 수 있음을 알 수 있었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.95-107
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• 2000

The primary purpose of dredging work is to maintain navigational readiness and to increase environmental amenity, so that the dredging project which is composed of excavating, removing, transporting, storing and disposing dredged material must be carefully managed to insure that dredging works are completed in a cost-effective and environmentally safe manner. The most important point in dumping operations is an estimating and reducing the impacts of discharges at the dumping area. One of the most effective method for the reduction of ecological impacts at dumping area is using the schematic process composed of the sophisticated plan, precise work and predicting/reducing the impacts based on the numerical model and field observation. In this study, the numerical model is used to predict the near-field spatial fate and begavior of effluent discharged from Confined Dumping Facility(CDF) located near coastal area. To to this purpose, reappearing of tidal current was preceded. The model is then applied to Mokpo harbor, where capital dredging and maintenance dredging are conducted simultaneously and the CDF is under construction;. In the series of model case study, we found that the near-field behavior of effluent discharged from CDF was governed by the receiving water condition, outfall geometry, characteristics of efflent and CDF operating conditions.

• Ocean and Polar Research
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• 제22권2호
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• pp.69-80
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• 2000

A 3-D particle tracking model with normalized characteristic equations has been developed to predict the variation of near-field mixing characteristics and the far-field transport of the effluent plumes discharged from sea outfalls. The model was applied to the case study on the Masan sea outfall plumes discharged through a submerged multiport-diffuser. Numerical simulations of the effluent transport for 15 days which cover neap and spring tidal cycles in Masan Bay were conducted using fall velocities of the solid wastes and the initial plume characteristics obtained from normalized near-field characteristic equations. The results showed that time variations in near-field minimum dilutions with tidal ambient flow conditions are about $45{\sim}49$. Most of the heavy particles in the effluent plumes were settled and deposited in the vicinity of the outfalls immediately, and the finer particles were transported eastwards 3 km away from the outfalls for 15 days. A similar depositional trend of contaminated sediment was also found during a recent field survey.

• Fisheries and Aquatic Sciences
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• 제13권3호
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• pp.236-243
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• 2010

Fecal sterols, nonylphenolic compounds (NPs), and polycyclic aromatic hydrocarbons (PAHs) were determined in surface water from Masan Bay and its adjacent rivers in February 2005. Concentrations of coporstanol (Cop), an indicator of fecal pollution, in surface water ranged from <10 to 13,853 ng/L, and concentrations of nonylphenol, the most toxic of the NPs, ranged from 10.2 to 481 ng/L, and concentrations of PAHs ranged from 8.61 to 223 ng/L. The concentrations of the compounds measured in this study were lower than or comparable to those at other locations in Korea and other countries. The contamination of Cop and PAHs in surface water was associated with the discharge from rivers passing through cities and/or industrial complexes. The NP contamination was associated with wastewater treatment plant (WWTP) effluents through outfalls as well as riverine discharge. Compared to ecotoxicological values, the concentrations of NPs from rivers, the mouths of rivers, and WWTP outfall areas exceeded guidelines, suggesting that hot spot areas may pose a potential risk to sensitive species.