• 환경영향평가
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• 제22권4호
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• pp.319-327
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• 2013

This study was conducted to identify runoff characteristics of pollutants using flow duration curve(FDC) and load duration curve(LDC) in Youngbon A watershed during 2009~2011. A flow rate and pollutant load in the study watershed were estimated by equation of stage-discharge and discharge-loads rating curve. From these methods, BOD, T-N, and T-P have evaluated whether water quality standards would have attained. Results showed that BOD loads of about 50% plotted above the LDC, while T-N and T-P loads of about 50% plotted below the curve. It means that BOD of about 50% have exceeded the water quality criteria, while T-N and T-P of about 50% have complied with the water quality standards. Meanwhile, BOD, TN and T-P loads plotted above the LDC of low flows, implying that they were more affected by point pollution sources than nonpoint pollution sources in the study watershed.

• 한국물환경학회지
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• 제37권3호
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• pp.175-189
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• 2021

In this study, 48 streams in the Sapgyo Watershed were selected, and the Load Duration Curves (LDC) were drawn up for each stream using water quality and flow monitoring over the last three years (2018-2020), and it was evaluated whether the target water quality was achieved for each flow section. As a result of evaluating whether or not the target water quality exceeded according to the LDC, it was found that 22 rivers exceeded the target water quality. Five rivers exceeded the target water quality due to point pollutant sources, 13 rivers exceeded the target water quality due to non-point pollutant sources, and 4 rivers exceeded the target water quality due to both point and non-point pollutant sources. Among the rivers that exceeded the target water quality due to point pollutant sources, which included domestic sewage of the untreated population, there is a need to reduce the influx of polluted loads by the untreated population. The use of eco-friendly fertilizers is recommended for rivers with a relatively high farmland ratio among rivers exceeding the target water quality due to non-point pollutant sources, and installation of boiling point reduction facilities that can reduce the amount of polluted load introduced during rainfall or manage water shores. In rivers with a large number of livestock breeding heads, the livestock houses located in these rivers need to be preferentially transferred to livestock manure treatment plants. Due to the high ratio of land area because of urbanization, initial rainwater treatment facilities are required to reduce the amount of pollutant load flowing into the river through the impermeable layer during rainfall.

• 복합신소재구조학회 논문집
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• 제6권3호
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• pp.50-61
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• 2015

This paper presents on the structural behavior of the the methyl methacrylate monomer (MMA) double wide flanged the glass fiber-reinforced polymer(GFRP) pipe composite structures for the manhole raise. The evaluation of structural performance on this composite structure was conducted by the axial load, fatigue load, and ultimate load test. The assessment indicates that the MMA double wide flanged GFRP pipe composite structures was confirmed safety, durability and reliability in result as expected. It was found that this composite structure was able to short working times to around 30-50% and construction costs to around 10-23% with compare other construction methods. Also, environmental pollution and civil complaints will be prevented because there will be no longer any noises, vibrations, dust, or construction wastes.

• 전기학회논문지P
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• 제56권3호
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• pp.123-128
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• 2007

Hydro power supplies no pollution energy, mainly induction generator has been applied at the small capacity power station. The generating power of small hydro-electric power station connects on the 22.9kV distribution system or low voltage system in the case of three-phase four-wire supply system. There are side effects of various kinds in the 3-three phase 4-wire distribution system mixing 1-phase load and 3-phase load. This system generates the voltage unbalance by unbalanced load operating condition. They have various serious effects on generator and connection system. In this paper, we analyzed what kind of operation characteristic are happened in the induction generator by customer load variation at the 3-three phase 4-wire distribution system.

• 한국농공학회논문집
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• 제52권4호
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• pp.19-26
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• 2010

To provide the basic information for the water quality management of the Sumjin River Basin, delivery ratios for flow duration were studied. Using the day-interval data set of discharge and water quality observed from the Chooryeong-cheon watershed, the flow-duration and discharge-load relation curves for the watershed were established, then the load-duration curve was constructed. Delivery ratios for flow duration were also developed. Delivery ratios showed wide variation according to flow conditions. In general, delivery ratio of high flow condition showed higher value reflecting nonpoint source pollution contribution from the forest dominating watershed. To resolve this problem, a regression model explaining the relation between flow rate and delivery ratio was suggested. The delivery ratios for different flow regime could be used for pollutant load estimation and TMDL (Total maximum daily load) development.

• 오토저널
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• 제4권2호
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• pp.47-57
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• 1982

Smoke, Hydrocarbon and Garbon Monoxide emissions of concern in environmental pollution on AVDS-170-2D diesel engine were studied experimentally and past studies on emissions of diesel engine were investigate. Engine speed and load were considered as variable factors influencing the emissions. The test results of a multicylinder, direct injection and turblcharged 4 cycle diesel engine were compared with past studies. Both emission levels of experimental study and past studies were markedly influenced by engine operation factors. The results obtained in this study can be summarized as follows; 1) Smoke intensity is proportional to engine load and varies with engine speed. 2) Hydrocarbon and nitric oxides emissions vary with engine speed and load. 3) Garbon monoxide emission is insensitive to engine speed and varies with engine load.

• 한국해양학회지:바다
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• 제19권2호
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• pp.155-163
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• 2014

마산만 표층퇴적물에서 미량금속의 오염도 및 잠재적 생태계 위해도를 평가하기 위하여 미량금속(Cu, Pb, Zn, Cd, Ni)의 총 농도 및 화학적 존재형태를 분석하였다. 미량금속의 농도는 Ni을 제외한 모든 금속이 만의 내측에 위치한 마산항 주변에서 높게 나타났다. 미량금속의 화학적 존재형태 중 Cd과 Pb은 비잔류 부분이 각각 92%, 88%로 인위적 기원에 의해서 주로 공급되는 것으로 나타난 반면, Ni은 잔류 부분이 70%로 주로 자연적 기원에 의해서 공급된 것으로 나타났다. 미량금속의 오염도 및 생태계 위해도를 다양한 지수로 평가한 결과, pollution load index (PLI)는 만의 바깥쪽 정점을 제외한 모든 정점에서 1을 초과하여 인위적 오염 상태를 보였다. Ecological risk index (ERI)는 만의 내측에서 considerable 또는 moderate risk 수준이었으며, 만의 바깥쪽에서는 low risk 수준이었다. Cd의 ecological index (Ei) 값은 대부분의 정점에서 높게 나타났으며, Cd이 산가용성 부분에서 가장 높은 농도를 보여 Cd이 마산만에서 저서생물에게 잠재적으로 높은 위해도를 미칠 것으로 판단된다.

• 한국물환경학회지
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• 제25권4호
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• pp.481-493
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• 2009

This study was conducted to performance appraisal of Total Maximum Daily Loads (TMDLs), especially in terms of performance on development & reduction plan and water quality status of unit watershed. Because load allocations for pollution sources were predicted redundantly by uncertainty of prediction, TMDLs master plan has been frequently changed to acquire load allocation for local development. Therefore, It need to be developed more resonable prediction techniques of water pollution sources to preventing the frequent change. It is suggested that the reduction amount have to be distributed properly during the planning period. In other words, it has not to be concentrated on the specific year (especially final year of the planning period). The reason why, if the reduction amount concentrate on the final year of the planning period, allotment loading amount could not be achieved in some cases (e.g., insufficiency of budget, extension of construction duration). If the development plan was developed including uncertain developments, it is necessary to be developed reduction plan considered with them. However, some of the plans in the reduction plan could not be accomplished in some case. Because, it is not considered financial abilities of local governments. Consequently, development plan must be accomplished to avoid uncertain developments, and to consider financial assistance to support the implementation of effective plan. Water quality has been improved in many unit watersheds due to the TMDLs, especially in geum river and yeongsang/seomjin river.

• 한국환경과학회지
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• 제19권1호
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• pp.39-45
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• 2010

When the Juam multipurpose dam which is connected with existing large water supply facilities is finished, water environment is changed from stream to lake. The changed quality of water should be examined. In this study, the result of water quality forecasting is analysed and an effective management plan of water quality is presented. Tn this study, the WASPS model that is a dynamic water quality simulation model was selected to forecast the water quality. This model forecasts movement of change of pollutants. For an application of the model, the subject areas were divided into seventeen sub-areas by considering change temperature depending measuring points and on depth of water. Meteorological data collected by the meteorological observatory and data about quality measured by the Korea Water Resources Development Corporation were used for an operation of the model. As a result of quality examination through quality data and estimated pollutant loading, the water quality environment criterion was grade II and the nutritive condition was measured as meso-graphic grade. In this study, an effective management was planned to improve water quality by reducing pollution load. According to the result of examination, when more than 30% of BOD was reduced it was recorded that the environment standard of water quality was improved to the second grade.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.739-746
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• 1999

Discharge characteristics of organic materials and nutrients were estimated in the catchment area of relaimed area-Saemankeum-. Discharge load of BOD5 was high in the domestic system, while nitrogen and phosphorous were discharged mainly from the livestock system and the land . Load was so dependent on the precipitation that it increased in the rainy season, particulary in nitrogen and phosphorus. Loads from nonpoint sources in this area were higher compared with others.