• 한국환경복원기술학회지
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• 제14권1호
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• pp.121-132
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• 2011

Removal rates of $NO_3$-N and TN in the free-water surface wetland system during winter; December, January, February and March, spring and fall; April, May, October and November, and summer; Jun, July, August and September were investigated. The system was established on floodplain in the downstream reach of the Gwangju Stream in 2008. It measures 50 meters in length and 5.5 meters in width. Iris pseudacorus L. grown in pots for about two years were planted in the system. The water stream was funneled in by gravity and its effluent was discharged back in. Volumes and water quality of inflow and outflow were analyzed from December 2008 to November 2010. The inflow was averaged approximately 350 $m^3/day$ and hydraulic residence time was about 3 hours. Average influent and effluent $NO_3$-N concentration was 3.75 and 3.35 mg/L, respectively and $NO_3$-N retention was amounted to 10.6%. Influent and effluent TN concentration were averaged 4.93 and 4.30 mg/L, respectively and TN abatement reached to 12.9%. One-way ANOVA statistics claimed that the average removal rates of $NO_3$-N and TN during winter, spring and fall, and summer were not always the same (p<0.001). The t-Tests of three pairs among $NO_3$-N removal rates of winter, spring and fall, and summer illustrated that the removal rates of winter ($5.04{\pm}1.94$), spring and fall ($10.53{\pm}2.24$), and summer ($18.61{\pm}2.26$) were significantly different each others (p<0.001). Among TN removal rates, the three pairs of t-Tests of three seasons showed that the removal rates of winter ($5.21{\pm}2.51$), spring and fall ($11.71{\pm}3.12$), and summer ($21.53{\pm}4.86$) were significantly different from each others (p<0.001).

• 한국농공학회논문집
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• 제46권5호
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• pp.141-153
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• 2004

Wetland system is widely accepted as one of natural water purification systems around the world for nonpoint sources pollution control. Constructed wetlands have become a popular technology for treating contaminated surface and waste water. In this study, the field experiment to reduce nonpoint source pollution loadings from polluted stream waters using wetland system was performed from June 2002 to March 2004. Four wetlands were used and the size of each one was 0.8ha. Water of Dangjin stream flowing into Seokmun estuarine reservoir was pumped into wetlands. Inflow and hydraulic residence time of the system was 500 $m^3$/day∼1,500 $m^3$/day, 2∼5 days, respectively. After 2 year operation, plant-coverage of the wetlauds was about 70% from bare soil surface at initial stage . Average water quality of the influent was $BOD_5$ 4.17 mg/L, TSS 18.45 mg/L, T-N 4.32 mg/L, and T-P 0.30 mg/L. The average removal rate of $BOD_5$, TSS, T-N and T-P during the study period was 5.6%, 46.6%, 45.7%, and 54.8%, respectively. Organic ($BOD_5$) removal rate was low and the reason might be low influent concentration. Wetland removal rate of T-P was about 10% higher than T-N. Performance of the experimental system was compared with existing data base (NADB), and it was within the range of general system performance. Overall, the wetland system was found to be adequate for treating polluted water stream with stable removal efficiency even during the winter period. Most of the nonpoint source pollutions from watershed are transported by streams or ditches, and they could be controled by constructed wetland system before entering the lake or reservoir.

• 대한기계학회논문집B
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• 제38권2호
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• pp.139-146
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• 2014

수소화붕소나트륨은 수소 에너지를 저장 및 공급할 수 있는 안정된 금속 물질이다. 본 논문에서는 탈수소 화학반응기 유로 설계를 위해 수력학적 직경 $461{\mu}m$를 가지는 마이크로채널에서 수소화붕소나트륨 수용액의 탈수소 화학반응이 일어날 때 수용액과 수소 기체 간의 이상유동 계면마찰에 대하여 실험연구를 수행하였다. 화학반응기 마이크로채널은 직사각 단면으로 높이 $300{\mu}m$, 너비 1 mm, 길이 50 mm 로 실리콘 웨이퍼에 공정되었으며, 가수분해 촉진을 위해 루테늄을 촉매로서 100 nm 두께로 채널 표면에 증착하였다. 가시화 결과 Re 수 30 이하에서 기포유동 양상이 관측되었다. 이상마찰승수는 기포율에 선형적으로 비례하며, 탈수소 화학반응기를 설계할 때 계면마찰에 영향을 미치는 수용액의 초기농도, 촉매 화학반응률, 체류시간을 고려해야 된다.

• 한국환경복원기술학회지
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• 제13권1호
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• pp.82-92
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• 2010

Removal rates of NO3-N and TN in a free water surface wetland system during emergent plant growing season and non-growing were investigated. The system was established on floodplain in the down reach of the Gwangju Stream in 2008. Its dimensions were 46 meters in length and 5 meters in width. Typha angustifloria L. growing in pots about two years were planted on the half area of the system and Zizania latifolia Turcz on the other half. Water of the stream was funneled into it by gravity flow and its effluent was discharged back into it. Volumes and water quality of inflow and outflow were analyzed from October 2008 to September 2009. Inflow into the system averaged approximately 715 $m^3$/day and hydraulic residence time was about 1.5 hr. Average influent and effluent $NO_3$-N concentration was 3.37 and 2.74 mg/L, respectively and $NO_3$-N retention amounted to 18.7%. Influent and effluent TN concentration averaged 4.67 and 3.69 mg/L, respectively and TN abatement reached to 20.9%. $NO_3$-N removal rate (%) during plant growing season ($22.67{\pm}3.70$, mean ${\pm}$ standard error) was significantly high (p<0.001) when compared with that during plant non-growing one ($15.02{\pm}3.23$). TN abatement rate (%) during plant growing season ($27.42{\pm}5.98$) was also significantly high (p<0.001) when compared with that during plant non-growing one ($13.66{\pm}3.08$).

• 한국물환경학회지
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• 제23권5호
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• pp.676-682
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• 2007

The bacterial number, extracellular enzyme activities and structure of bacterial community which are major constituent of aquatic ecosystem within the artificial vegetation island (AVI) were compared to those of the nearby pelagic lake waters in order to evaluate the possibility of the AVI as a eco-technological measure for water quality improvement and restoration of littoral zone in man-made reservoirs. There was not a significant difference in the total number of bacteria, but the number of active (viable) bacteria within the AVI was about 0.7 to 4.1 times higher than nearby pelagic lake water. The ratio of the number of active bacteria versus the total number of bacteria was also higher in the AVI than nearby pelagic lake water. The activities of ${\beta}$-glucosidase and phosphatase were 1.0 to 13.1 and 0.8 to 7.3 times higher respectively in the AVI than nearby pelagic lake water, showing that microorganisms were more active within the AVI. The bacterial communities of the two waters, examined by FISH method, did not indicate a clear difference in the springtime when the growth of macrophytes was immature, but during summer and fall it showed a clear difference indicating the formation of distinct bacterial community within the AVI compared to nearby lake water. From the results of this study, we conclude that AVI can contribute to make up the littoral ecosystem which show rapid cycling of matters through active detritus food chain in the dam reservoirs which have unstable aquatic ecosystem due to short hydraulic residence time and to strengthen the self-purification capacity of the lake.

• 한국물환경학회지
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• 제22권3호
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• pp.546-556
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• 2006

The purpose of this study is to improve the polluted stream water quality by pilot-scale five different constructed wetlands (CWs). Cell 1 to 3 are newly designed 2SFCW (Surface-subsurface flow CW) with 1 to 3 flow shifters (FS) in the middle of the wetland system. Cell 4 and 5 are control CW (CCW), but Cell 5 is the same type as Cell 3. The FS, which converts the route of surface and subsurface flow between two wetlands connected in series, was able to enhance the treatability of TN via nitrification and denitrification and of SS due to filtration and sedimentation. The void fraction and dispersion number of Cell 1, 2 and 3 obtained from the RTD analysis were found to be 0.73 and 0.17, respectively. COD and TP removal efficiencies of Cell 1 to 3 were similar to that of Cell 4 and 5. SS removal efficiencies of Cell 1 to 3 and 5 with FS were 5-10% higher than that of Cell 4 without FS. TN removal efficiencies of Cell 1 to 3 were 3-14% higher than that of Cell 4 and 5. The average $R^2$ values of COD, SS, TN and TP obtained from nonlinear regression analysis were similar to the results of other researchers.

• 한국습지학회지
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• 제20권4호
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• pp.330-337
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• 2018

소옥천 유역 내 본류 8개 지점의 수질 모니터링 자료를 이용하여 한국형 부영양화지수($TSI_{ko}$)를 산정하고 COD, T-P, Chl-a에 의해 계산된 인자별 $TSI_{ko}$를 이용하여 하천에 대한 환경특성을 분류하고 평가하였다. 소옥천 유역의 경우 수심이 얕고 강우시 비점오염 유입, 하수처리장 방류수 유입, 체류시간 증가 등으로 조류가 성장하기 좋은 조건을 갖추고 있어 연중 중영양 이상의 영양 상태를 보이고 있다. 특히 대청호 유입 지점인 추소 지점의 경우 수리학적 특성으로 인해 수질이 악화되어 부영양 상태를 나타내고 있었다. 따라서 소옥천에 대한 정밀 모니터링을 통해 원인분석과 이에 따른 수질개선대책 수립이 우선적으로 필요할 것으로 판단된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권5호
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• pp.39-48
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• 2021

Analysis of the change in water content and distribution was conducted according to the supply of recirculation water to a landfill. An excavation sample analysis showed that the recirculation water injection zone had water content 8.8% point higher than that of the non-injection zone, after 8 months of operation. And due to the influence of recirculation water supply by vertical wells in injection zones, the water content increases along with depth more clearly than non-injection zone. According to an electrical specific-resistivity survey after 13 months of operation, the water content got higher towards the bottom of the landfill. The water transmission coefficient is 8.72×10^-4 cm/sec for injection zones and 3.36×10^-5 cm/sec for the intermediate cover layer; analysis shows that the intermediate cover layer may affect the penetration velocity of water supplied by the horizontal injection tube. For the scientific design and operation of re-injection facilities, it was deemed necessary to follow-up research on the residence time and behavior of re-injection water considering the ratio of recirculation water supply in horizontal and vertical tubes, and pitcher coefficient of intermediate and waste layers.

• 환경영향평가
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• 제28권3호
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• pp.245-262
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• 2019

본 연구의 목적은 낙동강에 위치한 칠곡보와 강정고령보 구간을 대상으로 3차원 EFDC 모델을 구축하고, 보 구간의 운영 수위 저하 및 유속 증가와 같은 수리학적 특성 변화가 수질과 조류 생체량에 미치는 영향을 평가하는데 있다. 보정결과, EFDC 모델은 10분 단위의 고빈도로 측정된 상층과 하층 수온의 시간적 변화를 적절하게 모의하였고, 유기물, 질소, 인계열 수질항목과 남조류의 시계열 변화를 적절히 재현하였다. 하지만, 규조류와 녹조류 세포 밀도에 대해서는 모의값이 실측값을 과대 산정하였다. 규조류와 녹조류 예측의 오차 요인은 조류의 신진대사와 관련된 매개변수의 불확실성과 동물플랑크톤에 의한 포식기능이 모의에 포함되지 않은 것에 기인한 것으로 유추된다. 강정고령보의 보 운영 수위를 관리수위(EL. 19.44 m)에서 하한수위(EL. 14.9 m)까지 약 4.54 m 낮추어 운영하는 시나리오 모의결과, Chl-a와 조류 세포수 밀도가 급격히 감소했다. 특히, 녹조를 발생시키는 남조류 세포 수는 기존 관리수위에 비해 하한수위 시나리오에서 표층 기준 56.1% 급감하였다. 연구결과는 임계유속 유지가 남조류 제어에 효과적이라는 선행연구들과 일치하며, 강정고령보에서 수위 저하와 체류시간 감소와 같은 수리학적 조절은 조류의 과잉 성장을 제한 할 수 있는 대안임을 시사한다.

• 한국습지학회지
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• 제23권2호
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• pp.189-200
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• 2021

인공습지는 농업용 저수지의 수질개선을 위하여 많은 곳에 적용되고 있다. 인공습지는 수심분포, 유입량 및 유출량, 물흐름 분포, 체류시간, 수질 처리효율, 종횡비, 개방수역/폐쇄수역 구성비 등이 중요한 설계인자이다. 특히, 인공습지 높은 효율 증대를 위해서는 취입보 형식, 유입보, 인입수로 길이, 셀(Cell) 형태, 셀 연결 형태 등의 설계는 매우 중요하다. 본 연구는 농업용 저수지에 조성되어 운영중인 23개 인공습지의 현장조사를 통하여 설계시 고려하여야 할 인자 및 효율적 운영방안을 제시하고자 수행되었다. 인공습지 중에서 비정상적 운영이 나타나는 습지는 수위센서 미작동, 취입보 내부의 유사퇴적 및 기계식 수문틀의 협잡물 문제가 중요한 원인으로 나타났다. 또한, 인입수로의 길이가 길어질수록 취입보 하류부와 상류부의 생태적 단절구간이 늘어나는 것도 문제점으로 분석되었다. 습지 대부분은 2~5개의 셀로 조성되었으며 셀의 크기가 지나치게 클 경우 수리학적 효율이 떨어지고 관리가 어려운 것으로 평가되었다. 작은 규모의 습지에 많은 셀이 존재하는 경우 큰 수두손실로 인하여 적절한 유수흐름이 나타나지 않는 것으로 평가되었다.