• 한국해안해양공학회지
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• 제14권3호
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• pp.209-221
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• 2002

본 논문에서는 파랑에너지를 이용하여 항외의 해수를 항내로 유도하여 항내의 해수순환을 향상시키는 방법에 대하여 검토하였다. 파랑에너지를 활용하여 항내의 해수순환을 도모하기 위한 해안구조물로서는 월류제를 채택하여 제주외항에 적용하고 그 효과를 확률적인 관점에서 정량적으로 평가하였다. 월류제를 통한 해수유입량은 파고와 조위에 의하여 결정되는 것으로 가정하였으며 해수유입율과 파고 및 조위간의 함수관계는 수리모형실험 결과로부터 구하였다. 파랑수치모형의 후산자료와 검조소의 조위관측자료로부터 계산된 파고와 조위의 확률분포로부터 월류제를 통한 해수유입량의 확률분포를 구하는 방법을 제시하여 제주 외항에 적용한 결과 월류제를 통한 유량의 확률분포는 Gamma 함수에 근접하는 것으로 나타났으며 월류제의 최적위치에 대해서도 논의하였다. 그리고 월류제의 유무에 따른 항내오염확산을 계산하여 월류제에 의한 항내수질정화효과를 평가하였다.

• 도시과학
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• 제10권1호
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• pp.39-48
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• 2021

In this study, to evaluate the characteristics of the pollution in the major inflow tributaries and major environmental facilities in the watershed of Ara waterway, An inflow flow rate measurement and water quality analysis were conducted during dry and rainy seasons. In addition, the flow rate measurement, water quality analysis, and pollutant load at each monitoring point were compared and evaluated. Influx of BOD5, T-P and T-N into the tributaries of the ARA waterway watershed, excluding the Gulpo river watershed, during dry season were only 0.007%, 0.005% and 0.004% respectively of the incoming loads in the entire ARA waterway basin. In addition, it was confirmed that the discharge pollutant loads during rainfall event was about 440 times more for BOD5, about 545 times on T-P, and about 23 times on T-N in comparison to the pollutant loads during the dry days. When the Gulhyeon rubber dam was deflated, the discharged pollutant load during a rainfall was higher than the estimated load at the G7 monitoring point because the deposited pollutants from the upstream riverbed flowed down. Therefore, during a rainy season, it is necessary to manage the influx of high-load water pollutants from the overflow and deflation of the Gulhyun rubber dam as well as to find a strategy to reduce the pollutant loads in the Gulpo river watershed.

• 한국습지학회지
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• 제20권2호
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• pp.136-144
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• 2018

환경부에서는 유역단위의 통합 물관리를 위하여 물환경관리계획, 수질오염총량제 등을 실시하고 있으며, 측정망에서 측정된 수질을 이용하여 설정된 목표수질의 달성 정도를 판단하고 있다. 유역 하류부에 위치한 측정망의 지점에서의 수질 농도는 유역의 각 지류에서 오염원 유입과 하천의 자정작용 등의 복잡한 메커니즘을 거쳐서 만들어진 결과물이다. 이에 본 연구에서는 유역의 오염원 추적 및 초과율을 이용해 본류 및 지류의 수질이 목표수질 지점에 미치는 영향의 정도에 대하여 분석하였다. 이를 위해 오염총량제의 대상물질인 BOD와 T-P를 포함한 총 6가지의 수질항목에 대하여 FDC와 초과율 분석을 수행하였고, 이를 통해 목표수질 지점에 유황별 영향을 미치는 수질항목 및 지점을 도출할 수 있었다. 본 연구에서 제시한 FDC 분석을 통한 오염원 추적은 목표수질 달성을 위해 지류별 수질관리 전략을 보다 효율적으로 수립할 수 있을 것이다.

• 환경영향평가
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• 제22권2호
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• pp.171-181
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• 2013

In this study, we report the water quality characteristics of pollutants for 4 major tributaries in the Yeongsan and Sumjin river basins using statistical analysis, such as regression equation and factor analysis. The flow rate and water qualtiy data collected from 4 sampling sites(Hwangryoung A, Jiseok A, Chooryeong A, Osu A) in the Yeonsan and Sumjin river basin during the past 3 years were analyzed for 11 parameters(flow rate, dissolved oxgen, pH, water temperature, electric conductivity, biochemical oxygen demand, chemical oxygen deman, total organic carbon, total nitorgen, total phosphorus, suspended solid). The results showed that the concentrations of BOD, COD, TOC, T-N, T-P in Hwangryoung A(HW) and Jiseok A(JS) of the Yeongsan river basin were decreased as the flow rate was increased. This means that rather than nonpoint soources, point sources affect water quality. In the cases of Chooryeong A(CR) and Osu A(OS) in the Sumjin river basin, howerever, nonpoint sources than point sources are an important factor that affects the water quality. Also, the factor analysis technique was employed to analyze principal component influencing on water quality. The results revealed that the first principal component in HW was correlated with EC, DO, T-N, water temperature. This "nitrogen influx according to seasonal pattern" factor may be interpreted. In JS, the first principal component was correlated with BOD, COD, TOC and is likely to represent "organic matter" processes. In CR and OS, BOD, COD, TOC, SS and T-P were significantly correlated and is considered as representing "Organic matter and adsorption of phosphorus on sediments influx". This study is expected to contribute to the effective pollution control/management of the surfac waters in the study sites.

• Ocean Science Journal
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• 제40권2호
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• pp.79-89
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• 2005

Laboratory radiotracer experiments were conducted to determine assimilation efficiencies (AE) from ingested algal food and oxic sediment particles, uptake rates from the dissolved phase, and the efflux rates of Cd, Cr and Zn in the Asiatic clam Corbicula fluminea. Among three elements, AE from both algal and sediment food was greatest for Cd, followed by Zn and Cr. The AEs of tested elements from algal food (Phaeodactylum tricornutum) were consistently higher than those from sediments at a given salinity and temperature. The influence of salinity (0, 4 and 8 psu) and temperature (5, 13 and $21^{\circ}C$) on the metal AEs was not evident for most tested elements, except Cd AEs from sediment. The rate constant of metal uptake from the dissolved phase $(k_u)$ was greatest for Cd, followed by Zn and Cr in freshwater media. However, in saline water, the $(k_u)$ of Zn were greater than those of Cd. The influx rate of all tested metals increased with temperature. The efflux rate constant was greatest for Cr $(0.02\;d^{-1})$, followed by Zn $(0.010{\sim}0.017\;d^{-1})$ and $Cd\;(0.006\;d^{-1})$. The efflux rate constant for Zn in clam tissues depurated in 0 psu $(0.017\;d^{-1})$ was faster than that in 8 psu $(0.010\;d^{-1})$. Overall results showed that the variation of salinity and temperature in estuarine systems can considerably influence the metal bioaccumulation potential in the estuarine clam C. fluminea. The relatively high Cd accumulation capacity of C. fluminea characterized by the high AE, high dissolved influx rate and low efflux rate, suggested that this clam species can be used as an efficient biomonitor for the Cd contamination in freshwater and estuarine environments.

• 상하수도학회지
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• 제22권4호
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• pp.413-420
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• 2008

In order to utilize cinder melting slag as a filter media to control the quality of early rainwater, its environmental stability was verified by heavy metal elution experiment and improved by pre-treatment. Possibilities of improving its function as an absorbent was considered. Absorption characteristics of melting slag before and after the pre-treatment were analyzed by heavy metal equilibrium and stationary-phase column experiments, which in turn were analyzed by comparison experiment with activated carbon. As a result of heavy metal elution experiment, every metal item existed in a much lower amount than the criteria or was not detected, implying that there is no problem recycling it. Absorption equilibrium experiment showed that the time for pre-treatment melting slag to reach the equilibrium was reduced, while the absorbed amount was greatly increased. Stationary-phase column experiment assures us that the elimination rate was not changed much by influx rate, pH and the change in packing volume rate, indicating that this melting slag can be used not only as a filter media to control the quality of early rainwater but also in many areas of water-processing.

• 한국환경보건학회지
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• 제35권1호
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• pp.64-70
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• 2009

The aims of this study is to examine the effects of the changes in HRT(Hydraulic Retention Time) and media charge in a water-mill, among other operation factors, on the nitrogen and phosphorus removal in order to use up-flow anaerobic reactors, anoxic reactors and water-mill aerobic reactors for sewage treatment. The extension of HRT improved the nitrogen removal efficiency, however the removal pattern was constant regardless of HRT. The removal of phosphorus was constant (80%-90%) regardless of the change in HRT. The removal rate with change in influx load varied such that at the OLR (Organic Load Rate) of 1-3 kg/d, the T-N removal efficiency was 80.7%-88.9% and the T-P removal efficiency was 82.9%-89.3% while at the NLR (Nitrogen Loading Rate) of 0.108-0.156 kg/d the removal efficiencies were 80.7-88.9% (T-N) and 82.9-89.3% (T-P). The analyses of the nitrogen and phosphorous removal characteristics with the C/N and C/P ratio showed that the mean T-N removal rate was 88% at the C/N ratio of 1.2-2.6, and that the mean T-P removal rate was 86% at the C/P ratio of 7.2-14.1. Also, the analysis of nitrogen and phosphorous removal characteristics were analyzed in relation to media charge. The comparison between with and without media charge in the water-mill showed that while the nitrogen removal efficiencies were 86-94% and 85-89% respectively, the difference of phosphorous removal efficiencies were between the two conditions was not significant, thus it suggested that the media charge has less effect on the removal efficiency of phosphorous compared to that of nitrogen.

• 한국표면공학회지
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• 제51권5호
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• pp.316-324
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• 2018

Harsh seawater environment is subdivided into marine atmosphere, splash zone, tidal zone, submerged zone and bottom of sea depending on the exposed part. Since corrosion rate depends on the conditions of the exposed parts, proper protection and maintenance for each parts are essential for long-term use of steel structures in seawater environment. For steel structures which were installed in Shiwha Lake, a special maintenance system is required to guarantee its long-term durability and safety. As the tidal power plant has recently been operated, the salinity has risen due to the rapid influx of seawater upstream into Sihwa Lake and the corrosion tendency of the structure is variable according to the water level fluctuation. In this study, corrosion properties of steel structures under water level fluctuation was evaluated by corrosion rate measurement, visual inspection and natural potential measurement and their durability and life management were discussed in view of the effect of variation in of seawater level fluctuations in Shihwa Lake.

• Nuclear Engineering and Technology
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• 제15권4호
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• pp.256-266
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• 1983

가압 경수로에서 극심한 사고시 Debris/Water/Concrete 상호작용에 의한 Debris Bed 냉각과 격납용기과도 압력 평가가 제시되었다. 이 논문에서 제시된 Debris/Water/Concrete 해석모델을 MARCH 전산코드에 도입시켜 TMLB'와 S$_2$D사고분류에 따라 현존 용융 모델과 비교할 때 저속의 콘크리트 분해율과 소량의 개스 생성을 나타내는 반면 입자형 모델은 물과 상호작용이 지배적이며, 더 높은 격납용기 압력을 야기시켰다. 그 결과 Debris Bed의 열전달에 미치는 개스 유입효과는 중요하지 않음이 입증되었다.

• 한국토양비료학회지
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• 제22권3호
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• pp.221-227
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• 1989

토성(土性)이 다른 두 토양(土壤)의 압밀상태(壓密狀態)가 대두(大豆)의 근생장특성(根生長特性)과 양분(養分)의 흡수기능처리(吸收機能差異)를 알아보기 위하여 용적밀도(容積密度)와 수분상태(水分狀態)를 달리한 Core에서의 유근신장(幼根伸長)과 용적밀도(容積密度)를 달리하여 pot재배(栽培)하였을 때 근(根)의 총(總)길이와 표면적(表面積), 근반경(根半徑) 및 양분(養分)의 흡수속도(吸收速度)를 조사(調査)한 결과(結果) 다음과 같다. 1. 대두(大豆)의 유근신장(幼根伸長)은 용적밀도(容積密度)가 낮을수록 빨랐으며 양토(壤土)에서는 토양수분(土壤水分) 상태(狀態)가 - 4bar 이하(以下)에서, 사양토(砂壤土)에서는 - 1bar 이하(以下)에서 급격(急激)히 감소(減少)하였다. 2. 유근(幼根)의 신장(伸長)은 ELE경도계(硬度計) 토양강도(土壤强度) 2.0 이상(以上)에서 급격(急激)히 감소(減少)하였으며, 근신장속도(根伸長速度)와 토양강도간(土壤强度間)에는 2차식(次式)으로 표시(表示)되었다. 그러나 사양토(砂壤土)에서 -10bar이하(以下)의 토양수분상태(土壤水分狀態)에서는 경도(硬度)에 관계(關係)없이 근신장속도(根伸長速度)가 낮았다. 3. pot재배시험(栽培試驗) 결과(結果), 뿌리의 총(總)길이는 용적밀도(容積密度)가 $1.2g/cm^3$인 양토(壤土)에서 가장 길었으며, $1.4g/cm^3$인 사양토(砂壤土)에서 가장 짧았다. 세근(細根)의 평균직경(平均直徑)은 사양토(砂壤土)에서 생육(生育)한 것이 양토(壤土)에서 생육(生育)한 것보다 굵었다. 뿌리의 총표면적(總表面積)은 용적밀도(容積密度)가 낮을수록 넓었으며, 양토(壤土)에서 사양토(砂壤土)보다 넓었다. 4. 양분(養分)의 흡수량(吸收量)은 건물생산(乾物生産)이 많은 양토(壤土)에서 많았다. 단위(單位)뿌리표면적당(表面積當) 흡수속도(吸收速度)는 질소(窒素)가 양토(壤土)에서 $597{\sim}753n\;mole/day{\cdot}cm^2$, 사양토(砂壤土)에서 $222{\sim}365n\;mole/day{\cdot}cm^2$이었으며, 용적밀도(容積密度)가 높은 토양(土壤)에서 높은 값을 보였다. K는 $99{\sim}175n\;mole/day{\cdot}cm^2$ P는 $26{\sim}46n\;mole/day{\cdot}cm^2$이었고, Ca와 Mg는 각각(各各) $175{\sim}230n\;mole/day{\cdot}cm^2$, $163{\sim}205n\;mole/day{\cdot}cm^2$의 범위(範圍)를 보였으며 토양간(土壤間)의 차이(差異)는 질소(窒素)보다 적은 경향(傾向)이었다.