• KSBB Journal
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• v.27 no.3
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• pp.145-150
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• 2012

This study was accomplished using packed bed column reactors that contain nonsurface-modified polypropylene media and surface-modified media from hydrophobic surface property into hydrophilic property by ion beam irradiation. The objectives of this research was investigated the characteristics of organic compounds removal and microbe attachment from sewage of school cafeteria in these reactors. In 736.8 mg/L of the average inflow $COD_{Cr}$ concentration the reactors with and without surface modification showed 81.8% and 70.3% of average $COD_{Cr}$ removal efficiencies, respectively, which proves the $COD_{Cr}$ removal efficiency of surface-modified media reactor is higher than that of nonsurface-modified media reactor. After 90 days, there were maximum differences between modified system and non-modified system. In that time the maximum removal efficiency of $COD_{Cr}$ was 96.5% in modified system and was 85.2% in non-modified system that showed removal efficiency of surface-modified media system is 11.3% higher than that of nonsurface-modified media system. The average removal efficiency of SS was 80.4% for the surface modified system and 61.6% for the non-modified system under same condition. Also, the reactor of surface-modified media has advantage on microbe attachment and biofilm formation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.921-925
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• 2007

Gas removal characteristics of an air clean system, consisted of a filter and a nonthermal discharge plasma reactor with a magnetic field, have been investigated with emphasis on the enhancing gas removal efficiency of the applied magnetic field. It is found that the magnetic field influenced significantly to the corona discharge characteristics, decreasing the corona onset voltage and increasing the corona current. As a result, the proposed air clean system with the magnetic field showed the higher removal efficiency of the gas (e.g., trimethlyamine) than that of without the magnetic field. This would be because the magnetic field applied to the discharge plasma reactor of the air clean system can elevate the corona characteristics, and activate the generation of ozone, thus the removal efficiency of the gas was concurrently enhanced. This reveals that the proposed air clean system with the magnetic field could be used as an effective means of removal an indoor pollutant gas.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.2
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• pp.106-114
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• 1998

In this research, single-, two- and four-stage intermittently aerated activated sludge system were investigated for simultaneous removal of nitrogen and phosphorus with swine wastewater. For the comparison of removal efficiency, conventional activated sludge system was operated. Operational conditions of intermittently aerated activated sludge system were SRT 20day, HRT 24hr and aeration/nonaeration time 1hr/1hr, respectively. Nitrogen and phosphorus removal efficiency in Intermittently aerated activated sludge system was upgraded compare with conventional activated sludge system. In single-stage intermittently aerated activated sludge system, release-uptake of $PO_4^{3-}-P$ was observed very well but, phosphosrus removal in effluent was not effective. In single-stage intermittently aerated activated sludge system, release-uptake of $PO_4^{3-}-P$ in first reactor, was observed very well but, in following reactor, $PO_4^{3-}-P$ concentation showed almost no change. T-N removal efficiency in conventional activated sludge system, single-, two-, and four-stage intermittently aerated activated sludge system were 48, 87, 90.9 and 95.5%, respectively, and phosphorus removal efficiency were 48, 75, 97 and 95%, respectively. Intermittently aerated activated sludge system as a alternative processes of conventional system leads to meet satisfactory effleunt with only on/off aeration regulation and save energy for aeration.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.11-20
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• 2001

An anaerobic sludge-aerobic fixed-bed biofilm(packed with ceramic support carrier of 1 inch size) reactor system was built up to treat textile wastewater. The efficiency of reactor system was examined by determining the effects of textile wastewater ratio(from 25% to 100% at HRT 24 h). The influent range of SCOD concentration and color were 1,036~1,357 mg/L, and 1,487~1,853 degree, respectively. When textile wastewater ratio was 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% 100% and hydraulic retention time was 24 hours, SCOD removal efficiency by the anaerobic stage were 39.2% and the removal efficiency of the whole system were 75.8%. Color removal efficiency by the anaerobic stage were 45.4%(soluble color), and the removal efficiency of the whole system were 70.2%. In the A/A reactor system, the aerobic stage played an important role in removing both color and COD as well as anaerobic stage.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.194-197
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• 1999

Automatic weld bead removal system is consisted of bead removal tool, bead profile measurement system and tool motion control system. In this paper, design of weld bead profile measurement system which is used for automatic weld bead removal system is described. The system measures the weld bead position, normal vector of the auto-body and weld bead profile. The optical sensor with structured laser beam is used as a sensor and comparison of the sensor that can be used for this purpose is discussed in detail. The measurement process and the related software developed for this purpose are also described. A median filter, average filter and long line filters are used and their effects in bead profile measurement are discussed. The measurement system is integrated into automatic bead removal system and is used to remove weld bead in rear pillar of automotive body. The whole system operates well in automotive body assembly line and thus the system is proved to be good for this purpose.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.45-48
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• 2000

Reverse osmosis filtration(RO) system and ultrafiltration(UF) system are principally use for domestic home drinking water treatment systems. The object of this study is to make a comparison between two systems in terms of theirs abilities to remove RNA coilphage QB as an indicator of pathogenic enteroviruses. The virus removal ratio of RO system was 99.999%, which was higher than EPA virus treatment guideline(99.99%). In the course of filtration, removal ratios of sediment filter, pre-carbon filter, reverse osmosis membrane and post-carbon filter were 75.000%, 93.208%, 99.997% and 99.999%, repectively. In case of UF system, virus removal ratio was 99.708%. Removal ratios of sediment filter, pre-carbon filter, post-carbon filter and ultrafiltration membration membrane were 71.038%, 91.530%, 98.283% and 99.708%, respecively, in UF steps. Therefore, RO system is more effective than UF system in virus removal.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.4
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• pp.87-95
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• 2000

A vegetation purification system was applied to improve water quality of Masan Reservoir in Korea, which was composed of constructed wetlands in series. Five different kinds of macrophytes were planted in each wetland. The system was operated with the condition of low concentrations and high hydraulic loadings. Removal efficiencies(%) of chemical oxygen demand(COD) , total nitrogen(T-N) and total phosphorus(T-P) in this system were 9.0, 12.8, 20.1% , respectively. and removal rates(g/$m^2$/d) were 1.9(COD), 0.34(T-N) and 0.05(T-P) . Comparing this system with other wetlands operated at low hydraulic loadings, average removal efficiencies were low but removal rates were relatively high. Accordingly, this system could be applied to imporve reservoir water quality, because removal rates are more important than removal efficiencies in case of reservoir water quality improvement . However, the removal efficiencies and rates of this system are less than those of the hydroponic biofilter method which is a kind of a constructed wetland and utilize root zones of emergent macrophytes for trapping pollutants. Therefore, it is recommended that this system should be modified to utilize root zones of emergent macrophytes enough to improve reservoir water quality more efficiently.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.131-139
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• 2012

Field experiment was performed from June 2010 to July 2011 to evaluate pollutants removal efficiency in the constructed wetland system for the treated wastewater and the river water. The wetland systems were constructed near Gyungan river. Two different systems with meandering shape were compared for seasonal base and operational period base. Several kinds of aquaculture are planted through the corridor of wetland system. Average removal rate of BOD, T-N and T-P for A system were 15.8%, 14.8% and 26.5%, respectively. Average removal rate of BOD, T-N and T-P for C system were 23.5%, 27.8% and 10.6%, respectively. The effluent from two wetland systems often exceeded effluent water quality standards for wastewater influent, however effluent water quality standards for river water. However, the wetland system can be useful to treat polluted river water and effluent from wastewater plant. Removal rate of pollutants in seasonal variation was the highest in summer for BOD and T-N, however the removal rates of T-P were higher in spring and autumn than in summer.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.57-65
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• 1998

In this research, Effect of C/N ratio on nutrient removal in intermittently aerated activated sludge system(IAASS) was investigated with dormitary, building and swine wastewater. Three types (2-stage, 4-stage, modified) of IAASS were operated. Time interval of aeration/nonaeration in IAASS was 1hr/1hr. In treatment of Dormitary wastewater(BOD/T-N ratio : 4.4), Building wastewater (BOD/T-N ratio : 3.14) and swine wastewater(BOD/T-N ratio : 3.84), Nitrogen removal efficiency of 80, 70 and 90.4% was achieved, respectively. Nitrogen removal in IAASS was a great influenced on influent C/N ratio, efficient nitrogen removal was achieved at BOD/T-N ratio over 4. In IAASS operation, $\Delta $BOD mg/L/$\Delta $ nitrogen mg/L ratio was about 4-6. Simultaneous removal of organic, nitrogen and phosphorus in IAASS can achieved. And influent organic was efficiently utilized in denitrification. IAASS could be one of the best alternative process for the retrofit of conventional activated sludge system for the removal of nutrients.

• Journal of Environmental Health Sciences
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• v.25 no.3
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• pp.70-76
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• 1999

A laboratory experiment was performed to investigate the phosphorus removal using the activated sludge-electrolysis reactor which consisted of A$^2$/O system and aluminium electrodes as cathode and anode. In this system, the phosphorus was removed by aluminium ion, which was eluted from aluminiumelectrodes by electrolysis. In the batch experiments, when the current densities were 0.026, 0.052 and 0.08 A/dm$^2$, the phosphorus removal efficiencies for synthetic sewage were 66.4, 86.4 and 98.7% respectively. These results showed that the phosphorus removal efficiency increased with the increase of the current density. When the current values were 13, 26 and 40 mA respectively, the amounts of Al$^{3+}$ eluted from electrodes according to Faraday's law were 0.049, 0.07 and 0.12 g and Al/P mole ratio were 1.1, 2.0 and 3.41. In the continuous experiments, As hydraulic retention time(HRT) increased, COD and total nitrogen(T-N) removal efficiencies for domestic sewage increased. The average phosphorus removal rates of the activated sludge-electrolysis system were 97, 91, 80 and 80% at the HRT of 48, 24, 18 and 12 hours, respectively. Especially, the phosphorus removal rate in the activated sludge system with aluminium electrodes was higher than that in the system without aluminium electrodes.