• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.71-78
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• 2013

This study examined the feasibility of phosphorus removal from dewatering centrate/filtrate in wastewater treatment by struvite formation. Since dewatering centrate/filtrate obtained after anaerobic digestion contains a high content of ammonia, magesium addition and pH adjustment could remove phosphorous. The optimum magnesium dose, reaction time, settling time, and pH value was found at 2 mol Mg/mol $PO_4^{3-}$, 10 min, 120 min, and 8.5, respectively. A bench-scale continuous operation at the optimum condition showed 80% of total phosphorus removal and 82% of phosphate removal in dewatering centrate. The elemental composition and crystal structure of the chemical precipitate was similar to the reported values of struvite.

• Toxicological Research
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• v.34 no.3
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• pp.199-210
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• 2018

Skeletal muscle can be ultrastructurally damaged by eccentric exercise, and the damage causes metabolic disruption in muscle. This study aimed to determine changes in the metabolomic patterns in urine and metabolomic markers in muscle damage after eccentric exercise. Five men and 6 women aged 19~23 years performed 30 min of the bench step exercise at 70 steps per min at a determined step height of 110% of the lower leg length, and stepping frequency at 15 cycles per min. $^1H$ NMR spectral analysis was performed in urine collected from all participants before and after eccentric exercise-induced muscle damage conventionally determined using a visual analogue scale (VAS) and maximal voluntary contraction (MVC). Urinary metabolic profiles were built by multivariate analysis of principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) using SIMCA-P. From the OPLS-DA, men and women were separated 2 hr after the eccentric exercise and the separated patterns were maintained or clarified until 96 hr after the eccentric exercise. Subsequently, urinary metabolic profiles showed distinct trajectory patterns between men and women. Finally, we found increased urinary metabolites (men: alanine, asparagine, citrate, creatine phosphate, ethanol, formate, glucose, glycine, histidine, and lactate; women: adenine) after the eccentric exercise. These results could contribute to understanding metabolic responses following eccentric exercise-induced muscle damage in humans.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.571-576
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• 2004

Since anaerobic/anoxic/oxic process, which is a typical mainstream biological nitrogen and phosphorus removal process, utilizes influent organic matter as an external carbon source for phosphorus release in anaerobic or anoxic stage, influent COD/T-P ratio gives a strong influence on performance of phosphorus removal process. In this study, a bench scale experiment was carried out for SBR process to investigate nitrogen and phosphorus removal at various influent COD/T-P ratio and nitrate loadings of 23~73 and 1.6~14.3g $NO_3{^-}-N/kg$ MLSS, respectively. The phosphorus release and excess uptake in anoxic condition were very active at influent COD/T-P ratios of 44 and 73. However, its release and uptake was not obviously observed at COD/T-P ratio of 23. Consequently, phosphorus removal efficiency was decreased. In addition, the phosphorus release and uptake rate in anoxic condition increased as the nitrate loading decreased. Specific denitrification rate had significantly high correlation with organic materials and nitrate loadings of the anoxic phase too. The rate of phosphorus release and uptake in the anoxic condition were $0.08{\sim}0.94kg\;S-P/kg\;MLSS{\cdot}d$ and $0.012{\sim}0.1kg\;S-P/kg\;MLSS{\cdot}d$, respectively.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.563-570
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• 2004

Phased isolation intrachannel clarifier ditch process developed in this study is an enhanced biological nutrient removal process employing two ditches with intrachannel clarifiers. Bench-scale phased isolation ditch process was used to evaluate the system performance on municipal wastewater and detailed assessment of internal behavior in a ditch and each reactions. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31 days, and cycle times of 4hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 73~78%, and 65~90%, respectively. The internal behavior were well matched on each reactions such as nitrification, denitrification, and phosphorus release and uptake. As the SRT became longer, TN removal increased gradually, whereas TP removal decreased contrarily. However, the system was capable of producing an effluent TP concentration 1mg/L or less even at longer SRTs except the case of solids discharge by malfunction of intra-clarifier occurred by its geometrical limit. The system performance slightly decreased by hydraulic shock loading(increasing of influent flowrate and decreasing of system HRT). However, the higher system performance could be achieved again after four cycles. Thus, the system reliability could be successfully achieved short-term hydraulic shock loading that occurred in medium- and small-sized wastewater treatment plants suffering fluctuation of influent quality and flowrate during wet season.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.285-291
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• 2016

There has been an accelerating increase in water reuse due to growing world population, rapid urbanization, and increasing scarcity of water resources. However, it is well recognized that water reuse practice is associated with many human health and ecological risks due to numerous chemicals and pathogenic microorganisms. Especially, the potential transmission of infectious disease by hundreds of pathogenic viruses in wastewater is one of the most serious human health risks associated with water reuse. In this study, we determined the response of different bacteriophages representing various bacteriophage groups to chlorination in real wastewater in order to identify a more reliable bacteriophage indicator system for chlorination in wastewater. Different bacteriophages were spiked into secondary effluents from wastewater plants from three different geographic areas, and then subjected to various doses of free chlorine and contact time at $5^{\circ}C$ in a bench-scale batch disinfection system. The inactivation of ${\phi}X174$ was relatively rapid and reached ~4 log10 with a CT value of 5 mg/L*min. On the other hand, the inactivation of bacteriophage PRD1 and MS2 were much slower than the one for ${\phi}X174$ and only ~1 log10 inactivation was achieved by a CT value of 10 mg/L*min. Overall, the results of this study suggest that bacteriophage both MS2 and PRD1 could be a reliable indicator for human pathogenic viruses for chlorination in wastewater treatment processes and water reuse practice.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.480-487
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• 2004

This study was conducted to find the effect of electron acceptors on the formation of granular sludge by using four different types of electron acceptors. The phosphorous uptake, denitrification, and sulfate reduction in anoxic modes were simultaneously occured because of the presence of the polyphosphate accumultating organism(PAO) that utilize nitrate and sulfate as an electron acceptor in the anoxic zone. Denitrirying phosphorous removal bacteria(DPB) was enriched under anaerobic/anoxic/aerobic condition with a nitrate as an electron acceptor, and desulfating phosphorous removal bacteria(DSPB) was enriched under anaerobic/anoxic/aerobic condition with a sulfate as an electron acceptor. Polyphosphate accumulating organism(PAO) were enriched in the anaerobic/aerobic SBR. PAO took up acetate faster than DPB and DSPB during the aerobic phase. The sludge with nitrate and sulfate as an electron acceptors grew as a granules which possessed high activity and good settleability. In the anaerobic/aerobic modes, typical floccular growth was observed. In the result of bench-scale experiment, simultaneous reactions of phosphorus uptake, denitrification and sulfate reduction were observed under anoxic condition with nitrate and sulfate as an electron acceptors. These results demonstrated that the anaerobic/anoxic modes with nitrate and sulfate as an electron acceptors played an important role in the formation of the sludge granulation.

• Journal of Fashion Business
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• v.2 no.3
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• pp.166-179
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• 1998

The purposes of this study were to 1) investigate the problems in and the complaints from fashion textile converters and 2) develope the effective strategies to revitalize the converting business. This research study consists of two parts. The one part includes a study, on the domestic industry, which is mainly conducted through questionnaires, interviews and a review of related literature. The other part includes a study on the foreign industries. In case of Japan, survey was performed by visiting Japanese industry and interviewing Japanese converters. However, in case of Italy, a study was mainly conducted through a review of related literature and by interviewing Italian converters thru mail. As a survey instrument, a questionnaire was developed by the researchers after reviewing the related literature and interviewing textile converters. A questionnaire was distributed to 250 textile converters who were selected at random from the directory of textile converters which had been made by the researchers. All of the returned responses which include sixty four questionnaires were used for the analysis. The difficulties with which these converters confront are in a small scale and lack of specialty, professional training, and government support. Also, converters need an association or an organization that represent them. Cases of Japan and Italy were researched as examples of developed nation's. For instance, one of bench mark companies in development, planning and management, "Fashion Soft House" in Japan was analyzed. Regarding to Italy, the functions of the textile design studios which were mainly located around the silk complex, Como, were examined. Finally, on the basis of the results of this study, the strategies to revitalize the fashion textile converters include the tactics concerning management, production, education, improvement of the relationship between related industries, and the supportive policy by the government.

• Journal of the Korean housing association
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• v.26 no.3
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• pp.25-32
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• 2015

Apartment complex has become the major residental type of the urban structure. apartment complex has started to equip various subsidiary welfare facilities recently. environmental planning for play space has especially been important due to the growing attention over children's emotional development. In this study, arrangement types for play spaces in apartments to invigorate communication had been analyzed focusing on physical environment. based on previous studies, the arrangement of subsidiary welfare facilities can be categorized into dispersal type, concentrative type, affiliated type, and affiliated concentration type, and the elements to invigorate communication consist of circulative elements which contain location of play space and affiliated facility, visual elements which contain visual openness, and social elements which draw arrangement types of benches. the result of the analysis devide the arrangement type into concentrative type, affiliated type, and affiliated concentration type. referring to the location of play space, the first, if it is situated outside of apartment complex, theme-centered play space can be equipped to invigorate communication, the second, if it is situated in the center of the complex or outside of the apartment complex, low fence can be applied for free sight, and the last, straight type of bench arrangement should be used in big scale play space, aspectant type and gazebo type of the arrangement can be situated only outside of complex. This research could serve as a baseline of physical environment analysis to invigorate communication for play space in apartment complex.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.94-102
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• 2015

Electro-coagulation experiments were conducted with aluminum (Al) or iron (Fe) electrode in order to determine the optimal electrode material and operation conditions for algae removal. Al electrode showed higher removal rate of algae than Fe electrode because Al flocs have positive surface charges which electrostatically attract algae species having negative surface charges. Removal rate of algae and total phosphorous (T-P) was increased as current density and electrode area increases. It was also found that initial pH with neutral range was optimum for T-P removal by electro-coagulation. Bench-scale continuous flow experiments consisted of electro-coagulation reactor, agitation tank and settling tank were conducted. In electro-coagulation reactor, a large fraction of Al flocs were distributed to scum layer, due to the gas bubbles generated by electrolysis reaction. In agitation tank, most of Al flocs were settled and the optimal mixing intensity was found to be 50 rpm to achieve good settleability. The removal rate of algae was about 90-95%. Additionally, the removal rate of the T-P and COD was observed to be $73.8{\pm}8.0%$ and $75.0{\pm}3.8%$, respectively. Meanwhile, the removal rate of total nitrogen (T-N) was relatively low at only 24%.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.681-689
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• 2011

Submerged membrane bio-reactor (SMBR) has several advantages such as high MLSS, long SRT, and low F/M ratio at wastewater treatment. So, this has widely applied over the world and many studies have been conducted. However, membrane fouling remains an inevitable problem. This study was investigated using bench-scale SMBR with three poeration modes. Raw waters were prepared by addition of starch, acetic and fibric acid to recovery water of zeolite. The efficiency of nitrification and COD were very stable as about 95% and 80%, respectively. And critical flux was 128.8L/$m^{2}$/hr. The result of biodegradability test was following values at the each mode : Ss+Xs/$C_{T}$=81.7%, 35.1% and 45.3%, $X_{I}+S_{I}/C_{T}=18.3%$, 64.9% and 54.7%. When particulate matters such as $X_{I}$ and $X_{S}$ in influent are increased, membrane fouling will take place more and more. A relative ratio of filtration resistance to the fouling occurred by the cake layer was increased when increased the portion of $X_{I}$ and polysaccharide. It was thought that the formation of cake layer was promoted due to bond between $X_{I}$ and vicid material s generated from the polysaccharide.