• 한국수산과학회지
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• 제35권4호
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• pp.356-365
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• 2002

One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources and release from sediment. Therefore, to improve water quality, the reduction of these nutrients loads should be indispensible. At this study, the three-dimensional numerical hydrodynamic and ecosystem model, which was developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the eutrophication. The residual currents, which were obtained by integrating the simulated tidal currents over 1 tidal cycle, showed the presence of a typical counterclockwise eddies between Gyewha and Garyuk island. Density driven currents were generated westward at surface and eastward at the bottom in Saemankeum area where the fresh waters are flowing into, The ecosystem model was calibrated with the data surveyed in the field of the study area in annual average. The simulated results were fairly good coincided with the observed values within relative error of $30\%$. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of $40\~100\%$ pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to $59\%$ and $28\%$ in case of the $80\%$ reduction of the input loads from fresh water respectively. But pollution loads from sediment had hardly affected DIN and DIP concentration, The $95\%$ input load abatement is necessary to meet the DIN and DIP concentration of second grade of ocean water quality criteria.

• 한국해양환경ㆍ에너지학회지
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• 제6권4호
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• pp.37-44
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• 2003

목포항 해양수질개선에 대한 목포하수처리장 가동의 기여도를 평가하고 목포하수처리장 가동 후에 목포항에 유입하는 오염부하의 변화를 산정하기 위하여, 하수처리장 가동 전인 1997년 여론부터 1998년 봄까지의 건조기에 육지로부터 목포항에 유입하는 오염부하를 조사하고 목포항 주변의 하천들과 처리장 유출수의 계절별 유량 및 수질을 기초로 하여 유입오염부하를 산정하였다. 또한 하수처리장 가동 후인 1998년 겨울부터 1999년 볼까지 목포항에 유입하는 오염부하를 조사하고 목포하수처리장의 유입수 및 유출수의 오염부하를 산정하였다. 하수 처리장의 처리율은 화학적산소요구량(COD)이 약 49%, 총부유성고형물(TSS)이 약 76%, 휘박성부유물(VSS)이 약 79%, 총질소(T-N)가 약 3%, 용존무기인(DIP)이 약 7%, 총인(T-P)이 약 29%, 용존무기질소(DIN)가 약 -32%를 보였다. 하수처리장 가동으로 인한 목포항 내항수역 유입오염부하 변화율은 COD가 약 56%, TSS가 약 78%, VSS가 약 84%, DM이 약 45%, T-N이 약 22%, T-P가 약 34%, DIP가 약 -14%를 보였다. 목포항 전역으로 유입하는 총오염부하의 감소에 대한 하수처리장 가동의 기여율은 COD가 약 3%, TSS가 약 3%, VSS가 약 5%, DIP가 약 1%, T-P가 약 3%, DIN이 약 -1%로 나타났다.

• 한국환경과학회지
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• 제12권3호
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• pp.307-317
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• 2003

In this study, the material cycle model was applied to suggest alternative management of water quality for Jeju Harbor. The distribution of COD, DIN (dissolved inorganic nitrogen) and DIP (dissolved inorganic phosphorus) concentrations was reasonably reproduced by simulations on the model area of the Jeju Harbor using a material cycle model. The simulations of COD, DIN and DIP concentrations were performed under the conditions of 20∼100% pollution loadings reductions from pollution sources. In case of the 100% reduction of the input loads from Sanzi river, concentrations of COD, DM and DIP were reduced to 39%, 78% and 52%, respectively at Jeju harbor. In contrast, in case of the pollutant loadings reductions from sediment, the effect of DIN and DIP reduction relatively seemed to increase around the center of study area. The 95% reduction of the pollutant loadings from river and sediment is required to meet the COD and nutrients concentration of second grade of ocean water quality criteria.

• 한국물환경학회지
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• 제28권3호
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• pp.436-443
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• 2012

This research was focused on the effect of rice straw and rice straw mat on the reduction of upland field non-point source (NPS) pollution discharges. Six experimental plots of $5{\times}22m$ in size and 3% in slope prepared on gravelly sandy loam soil were treated with control, rice straw cover and rice straw mat cover. Radish in Spring growing seasons were cultivated. NPS pollution discharge was monitored and compared with respect to the treatments. The surface cover rate of rice straw and rice straw mat right after the treatments was 64.7% and 73.7%, respectively. Rainfall of the 16 monitored events ranged from 12.8 mm to 538.2 mm. Runoff coefficient of the events was 0.01~0.67 in control plot, 0~0.63 in rice straw plot and 0~0.45 in rice straw mat plot. The reduction of runoff compared to the control plot was 5.4~99.7% in rice straw plot and 32.9~100% in rice straw mat plot. The reduction of NPS pollution load was 52.0% for SS, 28.5% for T-N and 35.2% for T-P in rice straw plot and 79.8% for SS, 68.3% for T-N and 53.3% for T-P in rice straw mat plot. This research revealed that rice straw mat cover on the soil surface could not only increase the crop yield and farmer's income but also reduce the NPS pollution loads significantly.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2003년도 춘계학술발표회
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• pp.191-200
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• 2003

Gunsan coastal area is one of region increasing pollution problems. One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources. At this study, the three-dimensional numerical hydrodynamic and ecosystem model, which was developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the eutrophication. The residual currents, which were obtained by integrating the simulated tidal currents over 1 tidal cycle, showed the presence of a typical. Density driven currents were generated westward at surface and eastward at the bottom in Geum estuary area where the fresh waters are flowing into. The ecosystem model was calibrated with the data surveyed in the field of the study area in annual average. The simulated results of DIN were fairly good coincided with the observed values within relative error of 32.39%. correlation coefficient(r) of 0.99. In the case of DIP, the simulated results were fairly good coincided with the observed values within relative error of 24.26%, correlation coefficient (r) of 0.82. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of 20 ∼ 80% pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to 20∼80% and under 10% in case of the 80% reduction of the input loads from fresh water respectively. But pollution loads from sediment had hardly affected DIN and DIP concentration. For the environment management of coastal areas, in case of Kunsan area, the most important pollution sources affecting eutrophication phenomenon were found to be the input loads from fresh water.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3570-3576
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• 2013

본 논문은 홍천군의 마을하수도를 대상으로 하여 하수고도처리효율 및 삭감오염부하량을 산정하여 마을하수도의 기여율을 평가하였다. A2/O와 SBR 공법의 경우 BOD, COD에서 95%와 94%의 높은 처리효율을 보였으며, SS는 80%의 처리효율을 보였다. 반면 T-N과 T-P는 56%와 66%로 다른 항목에 비하여 비교적 낮은 처리효율을 보였으나 SS의 경우 MBR 공법에서 96%로 높은 처리효율을 보이는 것으로 관찰되었다. 다음으로 마을하수도 방류하천인 홍천강의 수질 경년적 변화를 관찰한 결과, COD와 T-N, T-P에서 수질이 크게 악화되고 있는 것으로 관찰되었으나, 마을하수도 설치 운영으로 일반 수질항목에서 80%이상, T-N과 T-P는 58%와 68%의 높은 오염부하 삭감량을 보이고 있어 홍천강 수질 개선에 크게 기여할 것으로 보인다.

• 한국습지학회지
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• 제18권4호
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• pp.342-349
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• 2016

낙동강수계에 속하는 안동시는 안동댐, 임하댐을 포함하여 낙동강이 흐르는 도시로 경상북도 신 도청 이전과, 지속적 도시화로 인해 불투수 면적이 증가하고 있어 강우 시 유출량 증가 및 비점오염원 부하가 증가되고 있는 지역이다. 본 연구에서는 물순환 선도도시에 선정된 도시 중 안동시를 대상으로 개발에 따른 유출량과 비점오염부하량을 비교 평가하였다. 안동시 물순환 선도도시 계획(안)에 대해 시 공간적 변화를 고려한 CN값을 이용한 직접 유출량과 BOD, T-N 및 T-P 비점오염부하량을 평가한 결과, 옥상녹화 및 투수포장 교체, 물순환 공원 및 거리 조성, 도심지 불투수층 개선 사업 등 4가지 scenario 모두 적용되어 개발될 경우 연간 직접유출이 10.41%, BOD 비점오염부하량이 20.56%, T-N 9.55% 및 T-P 비점오염부하량이 14.29% 저감되는 것으로 조사되었다. 4가지의 개발 scenario 중 저감률이 가장 높은 것은 도시지역 불투수면 개선 사업으로 조사되었으며 개발 이전 대비 연간 직접유출이 6.25%, BOD 비점오염부하량이 11.84%, T-N 비점오염부하량이 4.46% 및 T-P 비점오염부하량이 10.20% 저감되는 것으로 조사되었다.

• 한국농공학회논문집
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• 제54권2호
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• pp.27-35
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• 2012

Various Best Management Practices (BMPs) have been suggested to reduce Nonpoint source pollutant loads from agricultural fields. However, very little research regarding water quality improvement with sediment trap has been performed in Korea. Thus, effects of sediment trap were investigated in this study. Three sediment traps were installed at the edge of six plots and flow and water quality of inflow and outflow were monitored and analyzed. It was found that approximately 64.1 % of flow reduction was observed. In addition, pollutant concentration of outflow was reduced by 39.0 % for $BOD_5$. For SS, $COD_{Mn}$, DOC, T-N, T-P, approximately 62.1 %, 43.4 %, 43.5 %, 40.0 %, and 41.2 % reduction were observed, respectively. Over 80 % and 90 % of pollutant loads were reduced from sediment trap #2 and #3 because of less outflow from plots covered with rice straw/straw mat. In case of intensive rainfall events occurred from July 26~29, 2011, over 60 % of pollutant and 88.9 % of sediment reduction were observed from sediment trap #3. As shown in this study, small sediment traps could play important roles in reducing pollutant loads from agricultural fields. If proper management practices, such as rice straw/straw mat, are used to protect surface from rainfall impacts and rill formation, much pollutant reduction could be expected.

• Fisheries and Aquatic Sciences
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• 제6권3호
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• pp.149-154
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• 2003

The characteristics of pollutant loads from the various sources and seawater quality in Kwangyang Bay were evaluated. Total flow rate was estimated to be $10,868,066.8 m^3/day$ with a flow rate of R2l (the Seomjin River) as the highest one. Total COD, TN and TP loads of the input rivers and the ditches were about 27,591.8, 25,029.6 and 586.4 kg/day, respectively. Wastewater discharging loads was the greatest contributors to pollutant loads in the inner part of Kwangyang Bay. COD values in the inner part of the bay was over 3.0 mg/L, which exceeded the seawater quality criteria III of Korea. The average values of DIN and DIP were 8.62 ${\mu}gN/L\;and\;1.26\;{\mu}gP/L$, respectively. The limiting factor for algal growth was DIN. In he total discharging loads of the watershed from unit loading estimations, BOD, TN and TP were 9,132.3, 2,727.2 and 304.2 kg/day, respectively. In addition, municipal sewage by the population as pollution sources and the city of Kwangyang as administrative district had the highest loads. For a appropriate water quality recovery of Kwangyang Bay, it is suggested that it is essential to estimate reduction rate of total pollutant loads by water quality modeling.

• 동력기계공학회지
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• 제8권1호
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• pp.18-23
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• 2004

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments-were performed at various engine loads while the EGR rates were set from 0% to 20%. The emissions trade-off and combustion of diesel engine are investigated. Hot and cooled EGR are achieved without cooling and with cooling respectively. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar at load 20%.