• Korean Journal of Microbiology
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• v.37 no.4
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• pp.317-324
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• 2001

We have previously developed three stage methane fermentation system capable of digesting food wastes effectively and then releasing high organic wastewater as a final product. In this study, we tried to devise an ecological water treatment system, which can efficiently remove the nitrogen and phosphorus contained in the organic wastewater. The system was made of microbiological filters, algae, and waterfleas. Of two species of alga tested, Selenastrum capricornutum showed higher growth rate and more efficiently removed the nitrogen from the wastewater than by Chlorella sp. In addition, the highest growth rate and the nitrogen removal efficiency could be obtained when high concentrations of $Mg^{2+}\; and\; Ca^{2+}$ were added to the diluted wastewater and the molar ratio of nitrogen to phosphorus was adjusted to 10 : 1. In this study the population relationship between alga and water flea was also examined in a test tube. The initial number of algal cells decreased as the waterflea population increased. However, the number of algal cells gradually increased again when waterflea population decreased partly due to the environmental resistance. From these results, it was believed that the ecological water treatment system could be used for removing the nitrogen and phosphorus from organic wastewater very effectively. Moreover, the waterflea cultured by this system as a final predator could be used as a good foodstuff for fishes.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.296-302
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• 2014

The foliage of variegated Solomon's seal is excellent in cut flower arrangements. However, it has a restricted marketing period because the harvesting is limited in spring and summer. The increased interest requires the year-round production, thus techniques for dormancy breaking and forcing without low temperature treatment is needed. Therefore, experiments were conducted to d etermine whether gibberellic acid (GA) could break dormancy in variegated Solomon's seal. Thes prouting of dormant bud did not occur throughout the experiment when $GA_3$ $400mg{\cdot}L^{-1}$ was applied to dormant rhizomes as a soil drench. However, when plants were treated with a GA drench after scratch with razor blade or were given direct injection of GA, percent sprouting was increased up to 100 or 83.3%, respectively. However, because treatments with razor or syringe may damage internal organs, we tested another method, scarifying the rhizomes with sodium hypochlorite (NaOCl). Rhizome scarification with 4% NaOCl for 6 or 24 hours followed by drench of $GA_3$ $400mg{\cdot}L^{-1}$ increased the dormancy breaking percentage to 70 or 86.7%, respectively. Moreover, scarified and GA-treated rhizomes produced more leaves than untreated or GA-soil drenched plants in the glasshouse. These results showed the possibility of year-round production of variegated Solomon's seal foliage with rhizome scarification and GA treatments.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.29-35
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• 2007

Recently, due to narrow margin on design factor of flue gas desulfurization (FGD) systems or aging of systems, some problems such as decrease of $SO_2$ removal efficiency and difficulty on coping with unstable state are arising on FGD systems. On this study, to cope with these problems several methods such as adjustment of reagent pH, inlet $SO_2$ concentration, variation of units of operation pump, installation of liquid distribution ring (LDR) were attempted to increase the $SO_2$ removal using spray type simulated FGD system. Also, sulfite and Al/Fx ion effects on limestone blinding were experimented. When three absorber recirculation pumps were operated, $SO_2$ removal was increased by 12% in comparison with that of two pumps operation. $SO_2$ removal was increased by 2~7% after installation of LDR. Dissolved oxygen increased up to 0.5 ppm and limestone binding effect was alleviated after injection of dibasic acid (DBA) with the concentration of 500 and 1,000 ppm. When $Al^{3+}$ and $F^-$ ions were coexisting, the dissolution rate of limestone was decreased by 20%.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.151-156
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• 2009

The purpose of this study is to evaluate the affecting factors on Oil-Mineral Aggregates(OMA) for stranded oil on intertidal flat, because the OMA formation enhances the oil dispersion and biodegradation rates. We choose the affecting factors such as spilled oil concentrations(50, 100, 200, 300, 400, 500 mg/L), mineral concentration(100, 200, 500, 1,000, 2,000, 4,000 mg/L), salinity(10, 20, 30, 40 psu), shaking time(1, 2, 4, 8, 12, 24 hr) and applied dispersant volume(0, 5, 10, 15, 20%). Major conclusions derived from this study are as follows. It was observed that the kaolinite interacts three times strongly with crude oil than quartz. OMA formation was enhanced with increasing of spilled oil concentrations, whereas the increase of salinity rarely affected the OMA formation. The shaking time for OMA formation affected positively with kaolinite, but quartz was irrespective the shaking time. The applied dispersant enhanced the OMA formation by 13% in kaolinite and 56% in quartz experimental condition.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.967-972
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• 2003

The inner-diameter 5 cm cold hollow cathode ion source was designed for the high current density and the homogeneous beam profile of ion beam. The ion source consisted of a cylindrical cathode, a generation part of magnetic field, a plasma chamber, convex type ion optic system with two grid electrode, and DC power supply system. The cold hollow cathode ion sources were classified into standard type (I), electron output electrode modified type (II). The operation of the ion source was done with discharge current, ion beam potential and argon gas flow rate. The modification of electron output electrode resulted in uniform plasma generation and uniform area of ion beam was extended from 5 cm to 20 cm. Improved ion source was evaluated with beam uniformity, ion current, team extraction efficiency, and ionization efficiency.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.286-291
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• 2006

We studied possibility of mixing treatment of livestock wastewater and sewage using Phanerochaete chrysosporium PSBL-1. Our study showed that 97.6% of SS and 95% of T-P removal efficiency was achieved when 2 mL BF02(a coagulant) and 100 mL C-210EL(a cationic polymer) were added to the mixture(2:1, v/v) of livestock wastewater and sewage. We studied treatment characteristic of Phanerochaete chrysosporium PSBL-1, after were mixed pretreated wastewater and sewage by dillution ten times about livestock wastewater. The removal efficiency of NBDCOD(non-biodegradable COD), $NH_3-N$ and T-N was increased according to increase of pH. That is, T-N concentration of effluent was satisfied 60 mg/L by drain water waterqulity standard of livestock wastewater public treatment facilities with 35 mg/L from a lapse of five days at pH 6.7, 51 mg/L from a lapse of three days at pH 8 and 33 mg/L from a lapse of one day at pH 10. Moreover $COD_{Mn}$ concentration of effluent was satisfied 40 mg/L by drain water waterqulity standard of livestock wastewater public treatment facilities after a laps of one day at all pH. Organics and nitrogen concentrations of effluent were higher case with addition of V.A.(veratryl alcohol) than case without addition of V.A.(veratryl alcohol). $COD_{Mn}$ concentration of effluent satisfied drain water qulity standard of livestock wastewater public treatment facilities from a lapse of one day, when C/N rate(3:1) of influent was not controled. T-N satisfied that from a lapse of two days, when C/N rate was controled with $4{\sim}6$.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.1
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• pp.7-13
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• 2015

In this study, the effective treatment reducing geosmin and dosage of PAC was suggested when taste & odor compounds flow in. The removal efficiency of geosmin was evaluated with types of chlorination. In case of low geosmin concentration below 25 ng/L, removal efficiency of geosmin was estimated at 46% by combined treatment of pre and intermediate-chlorination. But, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 57%. In the medium geosmin concentration (25~79 ng/L), removal efficiency of geosmin was estimated at 59% by combined treatment. But, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 87%. When high geosmin concentration above 80 ng/L flows in, removal efficiency of geosmin was estimated at 69% by combined treatment. However, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 95%. Then, the exclusive intermediate-chlorination has an important effect on removal of geosmin. After correlation of geosmin concentration and dosage of PAC was analyzed, the coefficient of determination was estimated at 0.96. And, the proper PAC dosage chart was proposed. Also, at a initial occurrence of geosmin, when the combined treatment by intermediate-chlorination and PAC was applied, particle-bound geosmin should be removed continuously. Finally, it is proved that the combined treatment was effective to remove the geosmin by threshold levels as well as to reduce the dosage of PAC.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.739-746
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• 2008

The aim of this study is finding the optimal design parameters and the optimal operation variables of a reactive distillation column. Different from steady state optimization, dynamic optimization makes it possible considering operation ability as well as design problems at process design step. For performing dynamic optimization, dynamic simulation should be done first. If dynamic simulation is already finished, dynamic optimization can be performed with less effort than that of dynamic simulation.Reactive distillation systems involving reaction and separation in a single unit have the potential to reduce capital and operating costs, particularly when reaction have conversion constraint or when azeotropes exist making conventional separation difficult and expensive. This study here present work on the continuous distillation process, the homogeneous catalyzed esterification of methanol and acetic acid, the synthesis of methyl acetate. Based on an equilibrium stage model of a reactive distillation column a dynamic optimization problem was formulated and solved. And the results were verified by performing dynamic simulation and showing the variation of conversion and purity as the variation of the operation variables. As the results of dynamic optimization, this study found optimal feed ratio, reflux ratio and reboiler duty of this system. And as this study applied it to dynamic simulations the dynamic characteristics of a reactive distillation column are showed under optimal operating condition.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.3
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• pp.47-66
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• 1999

We have tried to measure the anti-dandruff effect of the several kinds of formulations by determining the MIC values of the P. ovale which was determined by resazurin(alarmar Blue$^{TM}$). To get high reproducibility, it was suggested that about 2.6$\times$10$^{5}$ cfu/$m\ell$ of P ovate should be incubated with alarmar Blue$^{TM}$, optimum dilution ratio between alarmar Blue$^{TM}$ and PBS buffer should be 1:1 -1:4, and optimum incubation time should be 16 ~ 24 hours. Even though 1:1 diluted alarmar Blue$^{TM}$ was incubated with P ovale, the metabolic activity of if ovule was not inhibited by alarmar BlueTM. The Minimum Inhibitory Concentration(MIC) values of several kinds of anti-dandruff formulation which were the mixture system between Zinc pyrithione and Climbazole make it possible to determine the optimal anti-dandruff formulation, which show similar results with that of microscopic MIC determination and that of SDDM(Skin-Disk Diffusion Method). It is expected that the anti-dandruff test method which uses alarmar Blue$^{TM}$ could be used as an effective in vitro test method because it was not so much affected by the turbidity of the broth and samples, and it can afford the MIC values of many samples within relatively short time by using microplate reader.te reader.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.248-254
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• 2016

Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.