• 상하수도학회지
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• 제29권3호
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• pp.319-323
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• 2015

This study investigated the effects of the light conditions on the productivity of scenedesmus dimorphus in the continuous mass cultivation system. To compare the algal productivity according to the light conditions, S. dimorphus was cultivated continuously under the wide range of light intensity(200-600 PPFD) and various light wavelength(white light and red-blue mixed light). After 100 days of cultivation under the different light intensity, the productivity of S. dimorphus increased as light intensity decreased. So, the productivity was maximized as 100 mg/L/d when light intensity was 200 PPFD. In case of light wavelength, the productivity of S. dimorphus was enhanced about 20% with the white light compared to that of the red-blue mixed light. Consequently, the optimal light conditions for the continuous mass cultivation of S. dimorphus were 200 PPFD as light intensity and white light as light wavelength.

• 상하수도학회지
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• 제27권3호
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• pp.325-329
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• 2013

A result of estimating the effects of initial phosphorus concentration and nitrogen sources on removal of nitrogen and phosphorus in wastewater treatment using Scenedesmus dimorphus shows that there was no difference in microalgae growth amount and nitrogen removal amount by phosphorus concentration(5 ~ 60 mg/L). On the other hand, as initial phosphorus concentration increased, phosphorus removal amount was increased by luxury uptake of microalgae. Scenedesmus dimorphus preferred to ammonia when ammonia(40 mg/L) and nitrate(40 mg/L) are simultaneously presented and nitrogen removal rate of ammonia was high at approximately 20 mg/L/day.

• 생태와환경
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• 제34권4호통권96호
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• pp.285-291
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• 2001

상위포식자에 의해 유도되는 Scenedesmus dimorphus (T$\ddot{u}$rpin) K$\ddot{u}$tzing의 군체형성에 관한 실험을 수행하였다. 동물플랑크톤 Daphnia magna (300 ind./L)와 Moina macrocopa (500 ind./L) 배양한후, $0.1\;{\mu}m$ (millipore)로 여과하여 얻어낸 용액 (ZFW)을 S. dimorphus가 1.8 ($10^5\;cells/ml$까지 자란 처리군에 첨가하여, ZFW를 넣지않은 대조군과 비교하였다. 대조군에 비해 두 동물플랑크톤 처리군에서 S. dimorphus의 군체형성의 유도가 뚜렷이 관찰되었다. 이 현상은 M. macrocopa 보다는 D. magna처리군에서 뚜렷하게 관찰되었으며, 첨가해준 ZFW의 양이 증가할수록 particle당 세포수도 비례적으로 증가하는 것으로 나타났다. ZFW처리군에서 1군체당 세포수(cells/colony)와 평균체적 (mean particle biovolume)은 $24{\sim}72$시간 사이에 급격히 증가하는 것으로 관찰되었다. S. dimorphus의 군체형성현상은 동물플랑크톤 D. magna와 M. macrocopa의 분비물에서 유도되는 화학물질의 영향으로 보이며, 이와 같은 형태변화현상은 동물플랑크톤의 포식에 대한 방어기작으로 작용하게 될 것으로 사료된다.

• 상하수도학회지
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• 제28권6호
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• pp.691-698
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• 2014

This study investigated the effect of a co-culture of Scenedesmus dimorphus and nitrifiers using artificial wastewater on the removal of ammonium, nitrate and phosphate in the advanced treatment. To test the synergistic effect of the co-culture, we compared the co-culture treatment with the cultures using S. dimorphus-only and nitrifiers-only treatment as controls. After 6 days of incubation, nitrate was removed only in the co-culture treatment and total amount of N removal was 1.3 times and 1.6 times higher in the co-culture treatment compared to those in the S. dimorphus- and nitrifiers-only treatments, respectively. In case of total amount of P, co-culture treatment removed 1.2 times and 12 times more P than the S. dimorphus -and nitrifiers-only conditions, respectively. This indicates that the co-culture improved removal rates for ammonium, nitrate, and phosphate. This further implies that there was no need for denitrification of nitrate and luxury uptake of P processes because nitrate and phosphate can be removed from the uptake by S. dimorphus. In addition, co-culture condition maintained high DO above 7 mg/L without artificial aeration, which is enough for nitrification, implying that co-culture has a potential to decrease or remove aeration cost in the wastewater treatment plants.

• 상하수도학회지
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• 제28권5호
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• pp.555-560
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• 2014

This study investigates the effect of sodium bicarbonate ($NaHCO_3$) on growth of S.dimorphus. $NaHCO_3$ concentration was varied from 0 to 2 g-C/L. As a result, the increase in concentration of $NaHCO_3$ up to 1.5 g-C/L increased dry weight of algae. The highest specific growth rate of S. dimorphus was $0.36day^{-1}$ which was obtained at concentration of 0.5 g-C/L $NaHCO_3$. pH showed a large variation range at the concentrations lower than 0.5 g-C/L $NaHCO_3$ whereas inorganic carbon, nitrate and phosphorus removal rates were almost same at the concentrations higher than 0.5 g-C/L $NaHCO_3$ (0.75, 1, 1.25, 1.5, 2 g-C/L $NaHCO_3$). Their average inorganic carbon, nitrate and phosphorus removal rate were 70 mg-C/L/d, 11.3 mg-N/L/d, and 1.6 mg-P/L/d, respectively. Thus, $NaHCO_3$ didn't effect on inorganic carbon, nitrate and phosphorus removal rate of S. dimorphus.

• 상하수도학회지
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• 제28권4호
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• pp.473-478
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• 2014

Microalgae is known as one alternative energy source of the fossil fuel with the small size of $5{\sim}50{\mu}m$ and negative charge. Currently, the cost of microalgae recovery process take a large part, about 20 - 30% of total operating cost. Thus, the microalgae recovery method with low cost is needed. In this study, the optimum current for Scenedesmus dimorphus recovery process using electrocoagulation techniques was investigated. Under the electrical current, Al metal in anode electrode is oxidized to oxidation state of $Al^{3+}$. In the cathode electrode, the water electrolysis generated $OH^-$ which combine with $Al^{3+}$ to produce $Al(OH)_3$. This hydroxide acts as a coagulant to harvest microalgae. Before applying in 1.5 L capacity electrocoagulation reactor, Scenedesmus dimorphus was cultured in 20 L cylindrical reactor to concentration of 1 OD. The microalgae recovery efficiency of electrocoagulation reactor was evaluated under different current conditions from 0.1 ~ 0.3 A. The results show that, the fastest and highest recovery efficiency were achieved at the current or 0.3 A, which the highest energy efficiency was achieved at 0.15 A.

• 상하수도학회지
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• 제29권6호
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• pp.643-649
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• 2015

Although microalgae are considered as a promising feedstock for biofuels, cost-efficient harvesting of microalgae needs to be significantly improved. In this study, the use of electro coagulation as a more rapid flocculation method for harvesting a freshwater (Scenedesmus dimorphus) microalgae species was evaluated. The results showed that, electro coagulation was shown to be more efficient using an aluminum anode than using an iron anode. And optimum conditions of electro coagulation for harvesting Scenedesmus dimorphus were found. The optimum stirring speed was 100 rpm and optimum pH was 5. Furthermore, the current density which the fastest and highest recovery efficiency is achieved at $30A/m^2$, while the highest energy efficiency was achieved at $10A/m^2$. A the rapid and high recovery efficiency indicate that electro coagulation is a particularly attractive technology for harvesting microalgae.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2001년도 한국생물과학협회 학술발표대회
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• pp.146.3-147
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• 2001

No Abstract, See Full Text

• ALGAE
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• 제21권1호
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• pp.83-90
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• 2006

Phytoplankton community in the coastal waters off the northeastern Korean Peninsula were characterized from May 2002 to August 2003. Taxonomic composition, abundance and biomass were determined at two water depths at 10 sample sites. A total of 153 phytoplankton species including 121 diatoms, 28 dinoflagellates, 7 green algae and 7 other species were identified. The mean abundance of phytoplankton varied from 15 to 430 cells mL–1 in the surface layer and from 11 to 545 cells mL–1 in the bottom layer, respectively. Phytoplankton was more abundant in coastal stations relative to those in more open ocean. The most dominant species were marine diatoms such as Thalassionema nitzschioides, Licmorphora abbreviata, Chaetoceros affinis and Chaetoceros socialis. In addition, a few limnotic diatoms including Fragilaria capucina v. rumpens, the green alga Scenedesmus dimorphus, some marine dinoflagellates and Cryptomonas sp. appeared as dominant species. Mean concentration of total chlorophyll-a varied from 0.22 to 7.87 μg chl-a L–1 and from 0.45 to 6.79 μg chl-a L–1 in the surface and bottom layers, respectively. The contribution of phytoplankton each size-fractionated varied highly with season. The contribution of microphytoplankton to total biomass of phytoplankton in the surface and bottom layer was high in February and August 2003, and that of nano-phytoplankton was high in May 2002 in both surface and bottom layers.