• 한국해양학회지:바다
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• 제4권4호
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• pp.275-288
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• 1999

유기물 투기에 대한 박테리아의 반응을 이해하기 위해 동해의 비투기해역과 투기해역의 유광대에서 1996년 4월부터 1997년 9월까지 총 5회에 걸쳐 박테리아 개체수, 박테리아 생산력, 아미노펠티다제(aminopeptidase; AMPase) 가수분해능, 베타글로코시다제(${\beta}$-g1ucosidase; ${\beta}$-GLCase) 가수분해능을 측정하였다. 비투기해역과 투기해역에서 유광대 수심으로 적분한 식물플랑크톤 생물량 및 박테리아 변수들을 비교해 본 결과, 전 시기에 걸쳐 일관되게 외양의 투기 정점에서 외양의 비투기 정점보다 ${\beta}$-GLCase 가수분해능이 항상 높았다. 또한 thymidine과 leucine 고정율로부터 추정된 박테리아 생산력도 계절에 관계없이 투기해역에서는 유의한 상관관계(균형성장)를 나타내었으나 비투기해역에서는 무관한 관계(불균형성장)를 나타내었다. 이러한 결과들은 투기해역에서 유기성 투기물의 지속적인 공급에 대해 박테리아 군집이 반응하고 있는 양상으로 보인다. 또한 계절에 관계없이 투기해역에서는 박테리아 개체수와 생산력이 양의 상관관계를 나타내었으나 비투기해역에서는 무관한 관계를 나타내어, 투기해역에서 박테리아 개체수의 조절 기작이 비투기 해역과 다름을 시사하였다. 그 밖의 변수들의 관계들은 연구 해역과 계절에 따라 변화하는 양상을 나타내어 봄과 여름에 박테리아 조절 요인들이 달라짐을 보여주었다. 이러한 변화가 수온, 수온과 관련된 현상, 또는 투기물 특성의 변화와 연관된 것인지에 대한 추가적인 연구가 필요하다.

• 한국항만학회지
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• 제14권4호
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• pp.429-439
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• 2000

The primary purpose of dredging work is to maintain navigational readiness and to increase environmental amenity. Therefore the dredging project, which is composed of excavating, removing, transporting and storing or dumping dredged material, must be carefully managed to insure that dredging works are completed in a cost-effective and environmentally safe method. The most important point in dumping operations is evaluating and decreasing the impacts of dumping works at the dumping area. One of the most effective method for this purpose is using the schematic process composed of the sophisticate plan, precise work and predicting/reducing the impacts based on an numerical model being closely linked with field observation. In this study, a numerical model is used to predict the spatial transport and fate of the effluent discharged from the confined dumping facility(CDF) located at a coastal area. To achive this purpose, numerical models were used for reappearing the tidal current of concerned area. These models were then applied to Mokpo harbpr where capital dredging and maintenance dredging are being conducted simultaneously and the CDF is under construction. In series of model case study, we found that the effluent discharged from CDF was governed by the receiving water condition and outfall geometry, so that limit of near-field was 14∼500 meter down stream and 4∼150 meter in transverse direction. dilution ranged from 1.1 to 8.2 on the cases. Long-term diffusion characteristics was governed by the dilution rate during near-field behavior, ambient conditions and CDF operation modes.

• 한국항해항만학회지
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• 제30권9호
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• pp.755-762
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• 2006

When we consider to develop a new harbor, the most important factor, we think, is the lowest water depth of waterway and approaching channel for safe navigation of vessel. The existing harbors have been being dredged to meet the international trend of jumbo sized vessels by adopting the new design criteria. As the dredged materials over the expected at the design level were common and there are still lack of land based reclamation area, we have no choice to discharge the dredged materials in open sea area In this study, we analysed the behavior of discharged materials at the dumping area of offshore, which were collected from the dredging work at the waterway in Busan New Port. We measured the tidal currents and analyzed the waters of dumping site after the dumping work. These were used to evaluate the numerical models. Suspended Solids(SS) were introduced to the diffusion model. Because of the characteristic of the dumping site, the speed of initial diffusion and settle down of the discharged materials was so fast. Therefore, we believe that the dumped materials do not cause a significant impact to the marine environment.

• 한국환경과학회지
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• 제22권11호
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• pp.1389-1402
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• 2013

This paper focuses on the impacts of waste dumping on inorganic nutrients in the dumping area of the Yellow Sea, and the effect of an governmental regulation of pollution in dumping areas. The environmental variables and parameters of the dumping and reference areas in the Yellow Sea were measured during July 2009 and analyzed. In addition, the analyzed data for inorganic nutrients over the last 10 years were obtained from the Korea Coast Guard (KCG) and the National Fisheries Research and Development Institute (NFRDI). The chemical environment of the study area revealed increases in concentrations of inorganic nutrients, Chemical Oxygen Demand (COD), and Volatile Suspended Solids (VSS) in the bottom layer. On the contrary, the pH level was decreased. Most notably, the time series data of inorganic nutrients showed gradual increase over time in the dumping area, and thus, the oligotrophic waters trend toward eutrophic waters. The increases appears to be due to the disposal of large amounts of organic waste. In recent times, the wastes disposed at the area were largely comprised of livestock wastewater, and food processing waste water. The liquefied waste, which contains an abundance of nutrients, causes a sharp increase in concentrations of inorganic nitrogen in the dumping area. On the one hand, the dumping sites have been deteriorated to such an extent that pollution has become a social problem. Consequentially, the government had a regulatory policy for improvement of marine environmental since 2007 in the dumping area. Hence, the quality of marine water in the dumping site has improved.

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.235-241
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• 2017

Purpose: It is to develop an agricultural three-directional dumping vehicle that can help farmers reduce intensive labor when carrying heavy loads and for easy dumping. In addition, a novel mechanism was applied for controlling the direction of the tilting cargo box by using a single hydraulic cylinder and simple apparatus. The overturning safety was analyzed to provide safe-use ground slope region of the vehicle to be used at upland fields and orchards. Methods: The developed three-directional dumping vehicle was constructed using a cargo box, vehicle frame, driving components, lifting components, and controller. The novel mechanism of controlling the dumping direction involves the operation of two latching bars, which selectively release or collapse the connecting edge between the vehicle frame and cargo box. A multibody dynamics analysis software (RecurDynV8R5) was used to determine the safe-use ground slope area when tilting the cargo box at slopes. A computer analysis was conducted by increasing the ground slope while rotating the vehicle when the cargo box comprised loads of 300 and 500 kg and stacking heights of 40 and 80 cm, respectively. Results: The three-directional dumping vehicle was successfully manufactured, and the cargo box was tilted at $37^{\circ}$ and $35^{\circ}$ for dumping forward and sideways. The latching bars were manually and selectively collapsed with the vehicle frame to control the dumping direction. When forward dumping, the safe-use ground slope was over $20^{\circ}$ in all vehicle directions and loaded conditions. Conclusions: A three-directional dumping vehicle was developed to reduce labor-intensive work in the farming environment. The user can easily control the dumping direction by using the control panel. The vehicle was safe to be used in most of the Korean upland fields and orchards (area over 96%) for the forward dumping.

• 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.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.180-185
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• 2001

In order to regulate the physical characteristics of an ocean dumping material in the south-eastern East Sea, the diffusion characteristics with the observation, hydraulic experiment and numerical experiment data are investigated. The main results are as follows; (1) Spying CTD observation result of the area of Jung in the East Sea, the ocean dumping area had influenced the Tsushima warm current of high temperature and salinity. Horizontal turbulent diffusivity is 1.913${\times}$10$^{7}$ $\textrm{cm}^2$/sec by drogue tracking. (2) From the experiment of settling, the initial settling velocity of each material is 1.0∼2.7 cm/sec according to the specific gravity and initial concentration. In the pycnocline, particles didn't settle under the pycnocline any more and accumulated. It is signified that calculation of the sedimentation rate of the ocean dumping material including of vertical diffustion must be regard the pycnocline in the ocean area have well-developed pycnocline. (3) Vertical turbulent diffusivity were 2.219${\times}$10$^{-8}$∼8,874${\times}$10$^{-4}$ $\textrm{cm}^2$/sec from the experiment of settling. And, the pycnocline influenced the vertical turbulent diffusivity. (4) From the result of diffusion simulation in the East Sea, the co-concentration line of 0.05 ppm and 0.1 ppm are limited at dumping area after 200 days. The constant concentration line of 0.01 ppm is distributed to the vicinity of Ulleungdo and Tokdo, but isn't distributed to the coastal area of East Sea and southern area of Jung in the East Sea.

• 한국해양학회지:바다
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• 제3권4호
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• pp.203-213
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• 1998

본 연구는 해양투기가 시작된 지 9 년이 지난 현재 황해 투기해역과 주변해역의 해수질 현황을 파악하여 해양투기가 해양환경에 미친 영향을 판단하고, 또한 투기해역 저층의 장기적인 영양염류 축적현상을 파악하여 해양투기의 적정성 여부를 판단하고자 하였다. 투기해역은 주변해역과 비교할 때 영양염류 등이 저층에서 높게 나타나며 pH, 용존산소 포화도 등 기타 화학적 요인의 국지적 변화가 뚜렷하여, 해양투기에 따른 생지화학적 영향이 투기해역에 나타나고 있는 것으로 판단된다. 정점간 화학자료를 통계변수로 하여 수괴에 대한 집괴분석(cluster analysis)을 실시한 결과, 연구해역은 수온약층 상층의 표층수괴와 수온약층 이심의 저층수괴로 크게 2 대분 될 수 있었으며, 저층수괴는 다시 축적현상이 대체로 심화되어 있는 투기해역 저층수괴와 주변해역 저층수괴로 나뉘어 질 수 있었다. 한편 화학종 변수들에 대한 집괴분석 결과, 연구해역의 화학적 특성은 pH, 용존산소 포화도 그리고 COD의 특성과 영양염류 등의 특성에 따라 크게 2 대분 될 수 있었다. 이는 투기해역 저층에서의 유기물 산화에 따른 용존산소의 소비, $CO_2$ 증가에 따른 pH의 감소 그리고 높은 COD와 영양염류 농도의 증가 등의 요인을 반영한다고 볼 수 있다. 따라서 이러한 연구결과는 투기해역이 해양투기에 의해 오염이 심화되고 있다는 사실을 뒷받침하는 것으로 사료된다. 한편 1987년 황해에서 해양투기가 시작되기 직전 투기해역 저층에서 연평균 $3.7{\mu}M$이던 총질소는 88년 해양투기 개시 이후 해마다 축적되어 92년에는 연평균 $5.7{\mu}M$로 증가되었으며, 본 연구가 수행된 96년과 98년에는 연평균 $8.3{\mu}M$에서 $9.5{\mu}M$까지 증가되어, 해양투기 이후 현재까지 영양염류가 약 250% 정도 농축되었다. 따라서 현재 황해의 투기해역은 환경용량을 초과하는 과도한 해양투기를 겪고 있으며, 이는 장기적으로는 황해 전반의 해양환경 및 수산환경에 악영향을 줄 가능성이 큰 것으로 판단된다.

• 한국해양공학회지
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• 제16권1호
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• pp.16-22
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• 2002

The diffusion characteristics of an ocean dumping material in the south-eastern East/Japan Sea related to regulate the physical characteristics with the observation and the hydraulic experiment are investigated. The main results are as follows; (1) Spying CTD observation result of the area of Jung in the East/Japan Sea, the ocean dumping area had influenced the Tsushima Warm Current of high temperature and salinity. Horizontal turbulent diffusivity is 1.913$\times$10$^{7}$ by drogue tracking. (2) From the experiment of settling, the initial settling velocity of each material is 1.0~2.7 cm/sec according to the specific gravity and initial concentration. In the pycnocline, particles didn't settle under the pycnocline any more and accumulated. It is signified that calculation of the sedimentation rate of the ocean dumping material including of vertical diffusion must be regard the pynocline in the ocean area have well-developed pycnocline. (3) Vertical turbulent diffusivity were 2.219$\times$10$^{-8}$ ~8.874$\times$10$^{-4}$ cm$^2$/sec from the experiment of settling. And, the pycnocline influenced the vertical turbulent diffusivity.

• Ocean and Polar Research
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• 제29권3호
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• pp.217-231
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• 2007

To explore limiting factors of spring bloom caused by waste disposal after dumping activity commenced in the Yellow Sea, we used a 1-dimensional temperature-ecological coupled model. The vertical structure of temperature and vertical diffusivity (Kh) are calculated by the temperature model with sea surface temperature using the 2.5 layers turbulence closure scheme. The ecological model applied results at the temperature model consisted of five state variables (DIN, DIP, phytoplankton, zooplankton, and detritus) forced by photosynthetically available radiation. We simulate year-to-year variations of plankton and nutrients using the coupled model from 1998 to 2000 and compare results of the model with observed data. It turned out that temperature is the growth factor of spring bloom in dumping area. During the winter the weak stratification made sufficient supply of the accumulated nutrients from the sea bed into the upper water column and led to the bloom in the coming spring. Radiation also turned out to be another important factor of spring bloom in the study area. Insufficient radiation of March 1999 showed low chlorophyll-a concentration despite sufficient nutrients in the surface.