• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.41-42
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• 1991

본 연구는 활성슬러지공법의 침전조를 막으로 대체하여 고액분리를 효과적으로 수행하도록 하는 막분리 활성슬러지 공법에 관한 것이다. 이와같은 방법은 공정자체가 간략화되는 동시에 종래법에서 슬러지 팽화(bulking)등에 의해 침전조에서 SS carry-over, 슬러지 침강성 향상을 위한 고부하처리의 곤란성, 침전조 처리수에의 SS 유출등 고액 분리의 문제점을 해소하므로, 여과, 응집침전, 혹은 활성탄흡착등의 고도처리설비없이 양질이 처리수를 얻을 수 있다고 보고 되고 있다.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.221-230
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• 2016

Multi-functional floating wetland island (mFWI) was developed in order to prevent algal bloom and to improve water quality through several unit purification processes. A test bed was applied in the stagnant watershed in an urban area, from the summer to the winter season. For the advanced treatment, an artificial phosphorus adsorption/filtration medium was applied with micro-bubble generation, as well as water plants for nutrient removal. It appeared that the efficiency of chemical oxygen demand (COD) and total phosphorus (T-P) removal was higher in the warmer season (40.9%, 45.7%) than in the winter (15.9%, 20.0%), and the removal performance (suspended solid, chlorophyll a) in each process differs according to seasonal variation; micro-bubble performed better (33.1%, 39.2%) in the summer, and the P adsorption/filtration and water plants performed better (76.5%, 59.5%) in the winter season. From the results, it was understood that the mFWI performance was dependent upon the pollutant loads in different seasons and unit processes, and thus it requires continuous monitoring under various conditions to evaluate the functions. In addition, micro-bubbles helped prevent the formation of anaerobic zones in the lower part of the floating wetland. This resulted in the water circulation to form a new healthy aquatic ecosystem in the surrounding environment, which confirmed the positive influence of mFWI.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.8
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• pp.878-883
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• 2006

Removal efficiency of As(III) was investigated with a pilot-scale filtration system packed with an equal amount(each 21.5 kg) of manganese-coated sand(MCS) in the bottom and iron-coated sand(ICS) in the top. Height and diameter of the used column was 200 cm and 15 cm, respectively. The As(III) solution was introduced into the bottom of the filtration system with a peristaltic pump at a speed of $5{\times}10^{-3}$ cm/s over 148 days. Breakthrough of total arsenic in the mid-sampling position(end of the MCS bed) and final-sampling position(end of the ICS bed) was started after 18 and 44 days, respectively, and then showed a complete breakthrough after 148 days. Although the breakthrough of total arsenic in the mid-sampling position was started after 18 days, the concentration of As(III) in this effluent was below 50 ppb up to 61 days. This result indicates that MCS has a sufficient oxidizing capacity to As(III) and can oxidize 92 mg of As(III) with 1 kg of MCS up to 61 days. When a complete breakthrough of total arsenic occurred, the removed total arsenic by MCS was calculated as 79.0 mg with 1 kg MCS. As variation of head loss is small at each sampling position over the entire reaction time, it was possible to operate the filtration system with ICS and MCS for a long time without a significant head loss.

• Economic and Environmental Geology
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• v.41 no.6
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• pp.709-717
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• 2008

Rhizofiltration for cesium uptake by sunflowers (Helianthus annuus L.) and beans (Phaseolus vulgaris var.) was investigated for groundwater contamination. The cesium removal by sunflowers was greater than 98% of the total cesium in solution, and the uptake by beans was also greater than 99% within 24 hours of the rhizofiltration, showing that the rhizofiltration has a great capability to remove cesium from the contaminated water system. Experiments at various pH of solution indicated that a solution of pH $5{\sim}9$ yielded very high cesium accumulation in two plants. From the results of the analysis for cesium accumulation in plant parts, about 80% of cesium transferred into the plant from solution was accumulated in the root part and less than 20% of cesium existed in the shoot part (including leaves). Results suggest that only the roots of the fully grown plant used for rhizofiltration should be disposed or post-treated and thus the cost and time to treat massive amounts of grown plants could be dramatically reduced when sunflower and bean are used in the real field. The results of SEM and EDS analyses indicated that the most of cesium were accumulated in the root surface as a ionic phase rather than a soil precipitation phase.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.715-721
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• 2017

Tree box filters, an example of bioretention systems, were compacted and versatile urban stormwater low impact development technique which allowed volume and water quality treatment performance to be adjusted based on the hydrologic, runoff quality and catchment characteristics. In this study, the overall performance of a 6 year-old tree box filter receiving parking lot stormwater runoff was evaluated. Hydrologic and hydraulic factors affecting the treatment performance of the tree box filter were also identified and investigated. Based on the results, the increase in rainfall depth caused a decrease in hydrologic and hydraulic performance of the tree box filter including volume, average flow, and peak flow reduction (r = -0.53 to -0.59; p<0.01). TSS, organics, nutrients, and total and soluble heavy metals constituents were significantly reduced by the system through media filtration, adsorption, infiltration, and evapotranspiration mechanisms employed in the tree box filter (p<0.001). This significant pollutant reduction by the tree box filter was also found to have been caused by hydrologic and hydraulic factors including volume, average flow, peak flow, hydraulic retention time (HRT) and runoff duration. These findings were especially useful in applying similarly designed tree box filter by considering tree box filter surface area to catchment area of less than 1 %.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.474-484
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• 2005

Biological treatment is a promising alternative to conventional air pollution control methods. Bioreactors for air pollution control have found most of their success in the treatment of dilute and high flow waste air streams containing volatile organic compounds and odor compounds. They offer several advantages over traditional technologies such as incineration or adsorption. These include lower treatment costs, absence of formation of secondary pollutants, no spent chemicals, low energy demand and low temperature treatment. The most widely used bioreactor for air pollution control is biofilter, but it has several limitations. In the past years major progress has been accomplished in the development of vapor phase bioreactor, in particular biotrickling filters. Biotrickling filters are more complex than biofilters, but are usually more effective, especially for the treatment of compounds which are difficult to degrade or compounds that generate acidic by-products. While the level of understanding of biotrickling filtration process for VOCs still remains limited, the evident success of biotreatment of VOC in air stimulated the pursue of acitve research. This paper presents fundamental and theoretical/practical aspect of air pollution control in biotrickling filter. Special emphasis is given to the operating parameters and the factors influencing performance for air pollution control in biotrickling filter.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.64-68
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• 2019

Purpose In the preparation process for N-13 Ammonia injections, there were radioactive medicines adsorbed on filters remarkably. Hereby, we have compared the adsorption rate and quality test on Millex GS filter and Satorious Minisart filter, both representatively hydrophilic sterilizing filters, also evaluated which filter is more accommodative for N-13 Ammonia injection. Materials and Methods The filters used for sterilization of N-13 Ammonia injections were Millex GS filter($0.22{\mu}m$) mand Satorious Minisart filter ($0.2{\mu}m$), which are generally used to strain aqueous solutions. After the N-13 Ammonia passes through each sterilization filter, the adsorption rate of the filter (n=10) is determined by measuring not only the radioactivity through the filter also the amount of radioactivity remaining in it using a Dose Calibrator. The N-13 Ammonia injections after each filter is tested by the quality control test to conform to the Samsung Medical Center standard. Results The ratio of radioactivity passed through Millex GS indicated $29.0{\pm}17.6%$. Satorious Minisart filters output was $80.9{\pm}3.2%$, respectively. Each ratio of radioactivity adsorbed on the sterile filter was $71.0{\pm}17.6%$ for Millex GS and $19.1{\pm}3.2%$ for the Satorious Minisart filters, respectively. Furthermore, on the ratio of filtered radioactivity, Using Satorious Minisart filter showed about 2.8 times higher than using Millex GS filter. The quality testing of N-13 Ammonia injections through each filter met the Samsung Medical Center standard. Conclusion The Millex GS filter is composed of cellulose acetate and cellulose nitrate, whereas the Satorious Minisart filter if composed only of cellulose acetate. Therefore, the presence of cellulose nitrate in the membrane seems to have made differences. Therefore, the use of Satorious Minisart filter in the preparation of N-13 Ammonia injection solution minimized the loss of radioactive medicines due to filter adsorption, thereby improving the synthesis yield.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.457-462
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• 2022

Manganese (Mn) exists in various oxidation states and Mn(II) is the most mobile species of Mn, which is toxic to plants and limits their growth. Therefore, the purpose of this study was to reduce Mn toxicity by immobilizing Mn using various adsorbents including iron oxides and calcium compounds. Ferrihydrite, schwertmannite, goethite were synthesized, which was confirmed by X-ray diffraction. Hematite was purchased and used as Mn adsorbent. Calcium compounds such as CaNO₃, CaSO₄, and CaCO₃ were used to increase pH and oxidize Mn. For Mn adsorption, Mn(II) solution was reacted with four iron oxides, CaNO₃, CaSO₄, and CaCO₃ for 24 hours, filtered, and the remaining Mn concentrations in the solution were analyzed by inductively coupled plasma optical emission spectroscopy. The adsorption rate and adsorption isotherm were calculated. Among iron oxides, the adsorption rate was highest for hematite followed by ferrihyrite, but goethite and schwertmannite did not adsorb Mn. In the case of calcium compounds, the adsorption rate was high in the order of CaCO₃>CaNO₃>CaSO₄. In conclusion, treatment of CaCO₃ was the most effective in reducing Mn toxicity by increasing pH.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.240-246
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• 2005

Humic substances HS) from process waters at advanced water treatment plant consisted of GAC and Ozone/GAC processes were isolated and extracted by physicochemical fractionation methods to investigate their characteristics. They are characterized for their functionality, chemical composition, spectroscopic characteristics using FT-IR and $^1H$-NMR spectroscopy. Humic fraction gradually decreased from 36.3% to 24.2% from 0.45 to 0.30 mgC/L) through ozonation and carbon adsorption. The humic fraction was isolated into the phenolic and carboxylic groups using A-21 resin, and the concentration of phenolic groups gradually decreased from 38.4% to 23.5% (from 4.9 to $3.2\;{\mu}M/L$ as phenolic-OH) through ozonation and carbon adsorption. In the case of carboxylic groups, the concentration decreased from 61.6% to 43.3% (from 7.8 to $5.8\;{\mu}M/L$ as COOH) through the water treatment processes. On the other hand, concentrations of those roups decreased from 38.4% to 24.0% and 61.6% to 44.9% through carbon adsorption without ozonation, respectively. The structural changes of HS identified from FT-IR and $^1H$-NMR were consistent with the results from the isolation of functional groups in HS.

• Membrane Journal
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• v.14 no.2
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• pp.149-156
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• 2004

This work focused on the degradation of natural organic matter (NOM) present in lake water using a combined pkotocatalysisimicrofiltration (MF) process. The system performances were investigated in terms of organic removal efficiency and membrane permeability. The addition of iron oxide particles (IOP) into the photocatalytic membrane reactor improved initial NOM removal by sorption, but during photocatalysis the removal efficiency was reversed, probably due to the scattering of UV light by IOP. The modification of TiO$_2$ surfaces by IOP deposition was conducted to enhance the photocatalytic NOM removal efficiency. A minimal amount of Impregnation of IOP on TiO$_2$ surfaces was required to prevent the light scattering effect as well. The coating of MF membranes with IOP helped to improve the NOM removal efficiency while sorbing NOM by IOP. Regardless of tile operating conditions and particles addition examined, no significant fouling was occurring at a flux of 15 L/$m^2$-h during entire MF operation.