• KSBB Journal
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• v.14 no.4
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• pp.414-421
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• 1999

The influenced of light intensity, cell density, and light pathlength on photosynthetic activity of Chlorella vulgaris were investigated. Since the light respon curve varied according to reaction conditions, the parameters estimated from nonlinear regression were proved to be apparent and could not be applied to various situations. The light response model incorporating the light penetration through the microalgal suspension was developed based upon the spatial distribution of the photosynthetic activity. This model showed a good agreement with experimental data at different cell densities and light intensities. Using the model the effects of cell density and light pathlenth were simulated and some dicussions about optimization of operation conditions of photobioreactors were carried out. Concludingly, the developed model can be useful for predicting microalgal photosynthesis and for determining the optimal operating conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1333-1337
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• 2006

표층수를 주요 취수원으로 활용하는 우리나라의 경우 저수지 내 남조류 대발생시 주로 인공순환에 의한 제어방안을 적용하고 있다. 본 연구에서는 간헐식 폭기장치를 사용중에 있는 H호를 대상으로 식물플랑크톤 제어 효과를 평가하고, 이에 따른 식물플랑크톤의 수직적 분포와 선택 취수와의 연관성을 규명하여 정수장 유입 원수의 수질을 향상하고자 하였다. 2005년 H호의 남조류 농도는 최대 $1.2mg/m^3 $ 수준으로 낮은 분포로 조사되었다. 남조강에 대한 폭기 효과는 6월에는 워낙 그 농도가 낮아 효과 분석 자체가 무의미 하였으나, 10월에는 비영향지점 보다 영향지점의 최대 농도가 약 28% 저감되는 효과를 확인하였다. 조사 기간 중 가장 높은 농도를 보인 조류강은 Cryptophyta이었으며 6월9일에 약 $5mg/m^3$ 농도로 측정되었다. 10월6일에는 Diatom, Bluegreen, Green algae, Cryptophyta가 비슷한 농도 분포로 혼재된 양상을 보였다. 다른 조류강의 경우 조사 기간 중 $3mg/m^3$ 이하의 농도로 측정되었다. 취수탑을 중심으로 설치하여 운영하는 간헐식 폭기장치 1기의 유효 영향 범위를 조사하기 위하여 폭기 영향권에서 식물플랑크톤 분포를 submersible fluorescence probe로 현장에서 실시간으로 조사한 결과 식물플랑크톤 밀도는 감소하고 수직적인 분포층은 깊어지는 현상을 보였다. 이러한 효과를 보이는 거리는 폭기 장치로부터 약 50m로 나타났으며 pH, DO, 수온항목의 결과에서도 같은 현상을 보였다. 이 결과에 따르면 현재 설치된 총 7기의 폭기 장치의 유효영향 범위는 최대 $0.07km^2$ 면적에 그 효과를 기대할 수 있을 것으로 판단되어, 남조 수화현상이 심화될 경우 인공순환에 의한 저감효과가 크지는 않을 것으로 예측된다. 조사 기간중 H호의 현존 식물플랑크톤량의 $60%{\sim}87%$가 수심 10m 이내에 분포하였고, 녹조강과 남조강이 우점하는 하절기에는 5m 이내에 주로 분포하였다. 취수탑 지점의 수심이 연중 $25{\sim}35m$를 유지하는 H호의 경우 간헐식 폭기장치를 가동하는 기간은 물론 그 외 기간에도 취수구의 심도를 표층 10m 이하로 유지 할 경우 전체 조류 유입량을 60% 이상 저감할 수 있을 것으로 조사되었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.61-69
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• 1987

In water treatment, prechlorination is often carried out to solve the troubles caused by Algae, but produces by-products that are known to be harmfull to human health. In this study, chlorine and chlorine dioxide used for algae removal process were compared in producing trihalomethanes and haloacetonitriles to study the possibilities in using chlorine dioxide as a alternative for chlorine. The raw water used for the study had 10,790 algae cells per one milliliter and Ankistrodesmus sp. were the most common.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.780-785
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• 2012

Existing states of attached algae in the sedimentation basin was observed during late april to early october, and the attached algae were visible 7 days after of cleaning the trough and the communities of algae became larger with increasing the operation periods. Attached algae community included bluegreen algae (Oscillatoria sp.), diatom (Synedra sp.,) and green algae (Mougeotia sp., Oedogonium sp.) and suspended diatom (Stephanodiscus sp.) as well. Diatom (Cymbella sp., Navicula sp., Synedra sp. and Stephanodiscus sp.), green algae(Mougeotia sp. and Cosmarium sp.) and blue-green algae (Anabaena sp.) were detected in the effluent of sedimentation basin. The chlorophyll-a (chl-a)concentrations of algae community on a square centimeter after 14 and 28 days were distinctively different depended on the copper sulphate treatment. The concentration of chl-a were $4{\mu}g/L/cm^2$ and $19{\mu}g/L/cm^2$ for the copper sulphate treated water and $59{\mu}g/L/cm^2$ and $147{\mu}g/L/cm^2$ for the untreated water. Diatom algae fragments were observed in red-brownish sediments on the bottom of industrial water distribution basin and degraded blue-green and green algae formated organic sediments combined with oxidized iron.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.420-428
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• 2005

Effects of three biological control agents such as Xanthobacter autotrophycus, Tanichthys albonubes and Oryzias latipes on the morphology and growth of cyanobacterium Microcystis aeruginosa were studied. The experiments were consisted of six treatments of living organism (LO) and culture filtered water of three organisms (CFW). Three LOs effectively decreased the density of M. aeruginosa, and then cyanobacteria hardy showed in the microscopic field after 5 days of cultivation. All LO and CFW agents induced the colonial formation of cyanobacterium M. aeruginosa, although there were little differences in colony formation according to the kinds, density and type of treatment. In particular, the higher density treatment of fish CFW induced effectively the colony formation of cyanobacteria, compared to the bacterial LO and CFW. Thus, the application of bio agents to control the cyanobacterial bloom is needed to the further study to diminish the adverse effects such as the enhancement of colony formation towards on the new bloom against the aquatic ecosystem.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.335-335
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• 2015

행주대교 하류 약 3km 지점에 위치한 신곡수중보는 한강종합개발 사업 중 하도정비로 인한 상시수위 저하로 인해 발생하는 문제를 해결하기 위해 설치되었으며, 취수장의 취수심 확보, 주운수심 확보, 염수 역류에 의한 생태계의 변화 방지, 하천 주면의 지하수위 저하 방지 목적으로 건설되었다. 본 연구에서는 신곡수중보의 존치, 이전 혹은 철거로 인한 수질변화를 모의를 실시하였다. 한강 본류와 임진강 합류를 고려하여 총 495개 수질모의 셀을 구성하였고, 수질모의를 위한 WQ Cell은 길이가 100 m~340 m로 임진강 47개, 한강 448개로 총 495개의 셀로 구성하였으며, 주요 지천이나 오염원으로 신곡보 하류에는 공릉천, 신곡보와 잠실보 사이에는 창릉천, 서남과 난지물 재생센터, 안양천, 홍제천, 중랑천, 탄천, 잠실보 상류에는 왕숙천, 월문천, 덕풍천 등 9개 지천과 2개 물 재생센터를 포함하였으며 잠실보 상류에서의 생활용수 취수를 고려하였다. 수온, BOD, 조류의 경계조건은 환경부에서 제공한 2011년 3월과 4월의 측정자료를 사용하였다. 그 결과, 신곡보 철거시 수온의 변화는 서해로부터의 차가운 해수의 역류 증가로 임진강, 파주, 전류, 장항습지까지 수온이 최대 $0.94^{\circ}C$ 크게 하강할 것으로 나타났으나 행주, 가양, 영등포는 오히려 수온이 $0.03{\sim}0.04^{\circ}C$ 미미하게 상승할 것으로 나타났으며 현재의 신곡보가 수온의 급격한 변화를 완층하는 역할을 담당하여 왔으나 보가 철거되면서 이러한 수온 완충역할이 사라지기 때문으로 분석되었다. 신곡보 철거시 BOD 농도의 변화는 잠실보 하류쪽으로는 BOD 농도가 최대 1.02 mg/l 감소하는 등 전반적으로 수질이 크게 개선될 것으로 나타나는 반면 잠실보 상류쪽으로는 BOD 농도가 최대 0.56 mg/l 증가하며 현재의 1급수 수질에서 2급수로 수질이 악화되어 상수원 수질 관리가 어려울 것으로 예상되었다. 신곡보 철거시 조류 농도의 변화는 잠실보 하류쪽으로 조류 농도가 최대 1.85 mg-A/l 감소하는 등 전반적으로 수질이 크게 개선될 것으로 나타나는 반면 잠실보 상류쪽으로는 조류 농도가 최대 0.40 mg-A/l 증가하며 고조위 기간에는 조류주의보 기준 1.5 mg-A/l를 초과하는 경우도 발생하여 상수원 취수에 문제가 발생할 가능성이 있는 것으로 나타났다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.1-17
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• 2019

In this study, the surveys were carried out from October (2016) to October (2017) along the tidal flat of Geunso Bay, Taean Peninsula of the western edge of Korea. The sampling trips were carried out for a total of 16 times, once or twice a month. In order to investigate the monthly variation of the microphytobenthos (MPB) biomass, community composition and photo-physiology were analyzed by HPLC (High performance liquid chromatography). The total chlorophyll a (TChl a) concentrations used as an indicator of biomass of MPB in the upper 1 cm sediment layer ranged from 40.4 to $218.9mg\;m^{-2}$ throughout the sampling period. TChl a concentrations showed the maximum level on $24^{th}$ of February and remained high throughout March after which it started to declined. The biomass of MPB showed high values in winter and low values in summer. The monthly variations of Phaeophorbide a concentrations suggested that the low grazing intensity of the predator in the winter may have partly attributed to the MPB winter blooming. As a result of monthly variations of the MPB community composition using the major marker pigments, the concentrations of fucoxanthin, the marker pigment of benthic diatoms, were the highest throughout the year. The concentrations of most of the marker pigments except for chlorophyll b (chlorophytes) and peridinin (dinoflagellates) increased in winter. However, the concentrations of fucoxanthin increased the highest, and the relative ratios of the major marker pigments to TChl a except fucoxanthin decreased during the same period. The vertical distribution of Chl a and oxygen concentrations in the sediments using a fluorometer and an oxygen micro-optode Chl a concentrations decreased with oxygen concentrations with increasing depth of the sediment layers. Moreover, this tendency became more apparent in winter. The Chl a was uniformly vertical down to 12 mm from May to July, but the oxygen concentration distribution in May decreased sharply below 1 mm. The increase in phaeophorbide a concentration observed at this time is likely to be caused by increased oxygen consumption of zoobenthic grazing activities. This could be presumed that MPB cells are transported downward by bioturbation of zoobenthos. The relative ratios (DT/(DD+DT)) obtained with diadinoxanthin (DD) and diatoxanthin (DT), which are often used as indicators of photo-adaptation of MPB, decreased from October to March and increased in May. This indicated that there were monthly differences in activity of Xanthophyll cycle as well.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.582-585
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• 2001

GL, a glycolipid type produced from yeast, inhibited the growth of bacteria and fungi. Algicidal effect by GL against dinoflagellate was motility stop and lysis. When over 10 ${\mu}g/ml$ showed strong algicidal effect. GL attached to the algal body directly.

• Korean Journal of Ecology and Environment
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• v.35 no.4 s.100
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• pp.257-265
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• 2002

The current study was performed to elucidate the relationship between the anatoxin -a produced by cyanobacteria and aquatic environmental factors, Algal and water samples were collected from the Daechung Reservoir from June to November 2001. The physical factors of the water quality were measured in sifu, while the biological and chemical factors were examined in the laboratory. The concentrations of anatoxin-a in the algal and water samples were analyzed by HPLC using a fluorescence detector, and ranged from $0.61-8.68\;{\mu}g/g$ dw in the algal samples and $0.01-0.08\;{\mu}g/L$ in the water samples. The suggested maximum concentration of anatoxin-a for safe drinking water is $1\;{\mu}g/L$. The concentrations of anatoxin-a in the algal and water samples were highest in July. The relationships between tile aquatic environmental factors and the anatoxin-a concentration were also analyzed to identify the crucial elements for toxin production. The anatoxin-a concentrations in the algal samples exhibited a high correlation with nitrate, the TN/TP ratio, TDN (P<0.05), and TPN/TPP ratio (P<0.01), whereas the anatoxin-a concentrations in the water samples were highly related to the water temperature, conductivity (P<0.01) , pH, phycocyanin, and phycocyanin/chlorophyll a ratio (P<0.05).

• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.507-524
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• 2019

The purpose of this study was to validate the EFDC model for the weir pool of Gangjeong-Goryong Weir located in Nakdong River, and evaluate the effect of flow control and phosphate loading reduction on the water quality and algae biomass by group (Diatom, Green, Cyanobacteria). As a result of model validation using 2018 experimental data,the time series of water level and vertical distribution of water temperature, DO, organic matter, nitrogen, and phosphorus time series were properly simulated. Seasonal fluctuations of algae biomass by group were adequately reproduced, but the deviations between measured and simulated values were significant in some periods. As a result of scenario simulations to control the water level and flow rate, the thermal stratification was resolved as the water level was lowered and the flow rate increased. The flow velocity at which the water temperature stratification was resolved was about 0.1 m/s, which is consistent with the previous study results of Baekje Weir in Geum River. Simulations of the 2Q flow scenario showed that Chl-a decreased by 8.7% and the cell density of diatom and green algae declined. The cell density of cyanobacteria increased, however, because the high concentrations of cyanobacteria in the upstream boundary conditions directly affected downstream due to increased flow velocity. In the scenario simulation of reducing the influent phosphate load concentration (average 0.056 mg/L) to 50%, Chl-a decreased by 13.6%.The results suggest that the upstream algae concentration and phosphorus load reduction should be considered simultaneously with hydraulic control to prevent algal overgrowth of Gangjeong-Goryong Weir.