• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.703-709
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• 2013

Among many microalgae cultivation types, heterotrophic culture with low cost carbon sources and energy saving culture method is crucial. A result of estimating the effects of pH on wastewater treatment using heterotrophic growing microalgae Chlorella sorokiniana shows that there was no difference in microalgae growth amount and nitrogen, phosphorus removal rate by wide range of pH(5 ~ 9). From pH 5 to 9, total nitrogen, phosphorous and glucose removal rates were 10.5 mg-N/L/d, 2 mg-P/L/d, 800 ~ 1000 mg/L respectively. This study reveals that C. sorokiniana cannot metabolite glycerol heterotrophically, however, glucose and acetate were proper carbon sources for growth and T-N, T-P and TOC removal. This research highlights the potential of heterotrophic microalgal growth with wastewater treatment plant with wide range of pH and carbon sources.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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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.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.357-362
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• 2017

Acetate, propionate, butyrate are the major soluble volatile fatty acids metabolites of fermented food waste leachates. This work investigate the effects of volatile fatty acid on the growth rate and $NH_4-N$, $PO_4-P$ removal efficiency of mixotrophic microalgae Chlorella vulgaris to treat digested food waste leachates. The results showed that acetate, propionate and butyrate were efficiently utilized by Chlorella vulgaris and microalgae growth was higher than control condition. Similar trends were observed upon $NH_4-N$ and $PO_4-P$ consumption. Volatile fatty acids promoted Chlorella vulgaris growth, and nutrient removal efficiencies were highest when acetate was used, and butyrate and propionate showed second and third. From this work it could be said that using mixotrophic microalgae, in this work Chlorella vulgaris, fermented food waste leachates can be treated with high efficiencies.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.3
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• pp.49-68
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• 2021

This study was to carried out to survey and analyse the vascular plants of Mt. Jangsan, Busan Metropolitan City, South Korea. The vascular plants were surveyed from June to October, 2019. The numbers of vascular plants in this site were 497 taxa and comprised of 106 families, 306 genera, 454 species, 7 subspecies, 29 varieties, 5 forms and 2 hybrids. The planted species were 16 taxa including Ginkgo biloba, Cedrus deodara, Zea mays and so on. In this study, 309 taxa were identified, including Selaginella rossii, Cyrtomium falcatum, Cephalanthera falcata and so on. The rare plants were 4 taxa including Hololeion maximowiczii(EN), Ottelia alismoides(LC), Iris ensata Thunb. var. spontanea(LC) and Sagittaria trifolia(DD). All rare plants were found in Jangsan Wetland. The Korean endemic plants were 9 taxa including Populus × tomentiglandulosa, Hemerocallis hakuunensis, Hosta minor and so on. The floristic target species were totally 53 taxa, which were 2 taxa of grade IV, 11 taxa of grade III, 6 taxa of grade II and 34 taxa of grade I. The alien plants were 58 taxa including Rumex crispus, Ipomoea purpurea, Helianthus tuberosus, Vulpia myuros and so on.

• Convergence Security Journal
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• v.13 no.5
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• pp.19-26
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• 2013

The Military Demarcation Line(MDL) divided the two Koreas when armistice agreement was signed in 1953, July 27 but there was no regulation for the sea border. Since then, The North has constantly denied the legitimacy of the sea border, which has remained the inter-Korean maritime border. But the armistice agreement has been virtual maritime demarcation line for the avoidance of hostilities on the Korean Peninsula and maintain and manage the armistice system peacefully. Therefore we should strengthen the Korea's sovereignty over the NLL by tightening the effective control.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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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.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1363-1374
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• 2010

This study examined the physical and chemical properties of soil in Jang-San wetland in Busan Metropolitan City. The wetland covers wide and flat area comparing to its outside. The samples of the wetland soil were collected and analyzed in order to identify the profiles and chemical properties. According to the analyses of soil moisture and particle size distribution, the wetland soil mostly belongs to sandy loam with the soil moistures of 14.9-153.2%. The soil profiles are configured with O, A, B, and C horizons from the land surface. The organic matter content (2.38-16.7%) at most sampling locations decreases downwardly with the highest at 0-20 cm depth. The organic matter content has a good positive relationship with soil moisture content. According to X-ray diffraction analysis, the wetland soils contain quartz and feldspar (the main components of rhyolite porphyry) as well as montmorillonite, gibbsite, and kaolinite (the weathered products of feldspar). The wetland soil displays the highest iron concentration (average 22,052 mg/kg), indicating oxidation of iron. High concentrations of potassium (average 17,822 mg/kg) and sodium (average 5,394 mg/kg) originate from the weathering of feldspar. Among anions, sulfate concentration is highest with average 9.21 mg/kg that may originate from sulfate minerals and atmosphere.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.6
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• pp.1-16
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• 2012

The research has analysed the targeted land situation, the composition of species, legally controlled plants, vegetation distribution, dominance, species diversity, and the similarity to evaluate the plant characterization of the eco forest in Jangsan, Busan. The results of the research is as following. The number of the plants that belongs to the area is 63 families, 126 genuses, and 163 species. Among them the fern plants : 4 families, 5 genuses, 5 species, and the egg species : 5 families, 8 species, 10 species, and angiospermae : 54 families, 113 genuses, 148 species have been checked. Monocotyledoneae of angiospermae : 7 families, 20 genuses, 22 species (13.5%) and dicotyledoneae : 47 families, 93 genuses, 126 species (77.3%) have been totally checked. The endangered wildlife species by the standard of the Ministry of Environment and the rare plants by the standard of IUCN evaluation realesed by the Bureau of Forest and National Plant Institution has never been checked but one species of Weigela subsessilis has been checked as an approving plant in being delivered abroad, the 8 imported plant by the standard of National Plant Institution checked, some disturbing ecosystem plants released by the Ministry of Environment (2009) not emerged. The succession into the oak trees is occurring to the biodiversity of the researched area, the number of species and their species diversity.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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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.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.5
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• pp.573-579
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• 2014

VFAs like acetate are the major soluble metabolites of food waste leachates after digested. Therefore this study investigates the effect of acetate on growth rate and nutrient removal efficiency of Chlorella vulgaris to treat digested food waste leachates. The initial acetate concentration varied from 0 to 20 mM. As a result, Chlorella vulgaris growth rate was increased as high as the concentrations ranged from 0 to 20 mM. The same trend was observed with $NH_4$-N and $PO_4$-P consumption. The highest growth rate and the highest $NH_4$-N, $PO_4$-P removal rate were observed at acetate concentration of 20 mM. The microalgae growth rate and $NH_4$-N, $PO_4$-P removal rates were 1.5, 1.8, 2.3 times higher than the condition without acetate.