• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.103-113
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• 1993

Every year, over $3.37{\times}10^7$ ton of municipal solid waste is generated in Korea, of which about 28% is organic food waste from restaurant, dining halls and households etc. Methane conversion of the food waste by anaerobic digestion could be a viable approach for energy recovery as well as safe disposal of the waste. However, as food waste is composed of highmolecular complex polymers such as cellulose, lignin and protein, anaerobic digestion of food waste has not been efficient in terms of volumetric loading rate, solid retention time and extent of anaerobic degradation. In this research, the improved anaerobic degradation of food waste was attemped by applying rumen microorganisms to anaerobic digestion. Acidification efficiency of food waste by rumen microorganisms was compared with that of conventional acidogenesis. And optimum acidification conditions by rumen microorganisms were also determined. For the experiments, anaerobic batch reactors of 600 mL was fed with the processed (dried and milled) food waste obtained from a restaurant. Ultimate volatile fatty acid (VFA) yield produced by rumen microorganisms was about 8.4 meq VFA/g volatile solid (VS) that is 95% of the theoretical value. This yield was not much different from that of conventional acidogenesis, but hydrolysis rate was about twice faster. Cumulative VFA concentration increased from 66 meq/L to 480 meq/L, when the initial TS was increased from 1% to 15%. But VFA yield at 15% TS was half of that at 1% TS. This inhibition on the acidification might be caused by the rapid drop of pH and higher concentration of nonionized VFA. Optimal pH and temperature range for the acidification were about 6.0~7.5 and $35{\sim}45^{\circ}C$, respectively.

• Journal of Wetlands Research
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• v.7 no.4
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• pp.67-80
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• 2005

Vegetation structure of the vascular plants was investigated from April 2003 to August 2003 in Hwangjeong wetland around Geumho River, Yeongcheon-si, Gyeongsangbuk-do, Korea. Actual vegetation of Hwangjeong wetland largely can be classified by the floristic composition and the physiognomy into 12 communities; Ambrosia artemisiifolia var. elatior, Humulus japonicus, Miscanthus sacchariflorus, Phragmites japonica, Zizania latifolia-Miscanthus sacchariflorus, Zizania latifolia-Nymphoides peltata, Miscanthus sacchariflorus-Phragmites japonica, Phragmites communis-Phragmites japonica, Phragmites japonica-Salix gracilistyla, Salix koreensis-Salix glandulosa, Salix nipponica-Salix koreensis, and Phragmites japonica-Zizania latifolia. Among them, the distribution area of the Phragmites japonica community was the largest as 49.46 ha(11.03%). The dominant vegetation type was Phragmites japonica community and Ambrosia artemisiifolia var. elatior community based on the phytosociological method, and Phragmites japonica community was classified into two subcommunities; Nymphoides peltata subcommunity and Salix glandulosa subcommunity. Differential species of Phragmites japonica community were Phragmites japonica, Miscanthus sacchariflorus, Persicaria thunbergii, Oenanthe javanica, Leersia oryzoides var. japonica, and Rorippa indica; differential species of Ambrosia artemisiifolia var. elatior community were Ambrosia artemisiifolia var. elatior, Setaria glauca, Commelina communis, Cyperus orthostachyus, Digitaria sanguinalis, Xanthium strumarium, Erigeron annuus, Erigeron canadensis, Kummerowia striata, Trifolium repens, and Medicago sativa; differential species of Nymphoides peltata subcommunity were Nymphoides peltata, Zizania latifolia, Scirpus tabernaemontani, and Eleocharis mamillata var. cyclocarpa; differential species of Salix glandulosa subcommunity were Salix glandulosa, Salix koreensis, and Salix gracilistyla. It was expected that Hwangjeong wetland is worthy of conservation contributed purifying water pollution, giving habitats of many lifes, and providing beautiful scenes of Geumho River.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1092-1099
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• 2022

Research on exhaust aftertreatment devices to reduce air pollutants and greenhouse gas emissions is being actively conducted. However, in the case of the particulate matters/nitrogen oxides (PM/NOx) simultaneous reduction device for ships, the problem of back pressure on the diesel engine and replacement of the filter carrier is occurring. In this study, for the optimal design of the integrated device that can simultaneously reduce PM/NOx, an appropriate standard was presented by studying the flow inside the device and change in back pressure through the inlet/outlet pressure. Ansys Fluent was used to apply porous media conditions to a diesel particulate filter (DPF) and selective catalytic reduction (SCR) by setting porosity to 30%, 40%, 50%, 60%, and 70%. In addition, the ef ect on back pressure was analyzed by applying the inlet velocity according to the engine load to 7.4 m/s, 10.3 m/s, 13.1 m/s, and 26.2 m/s as boundary conditions. As a result of a computational fluid dynamics analysis, the rate of change for back pressure by changing the inlet velocity was greater than when inlet temperature was changed, and the maximum rate of change was 27.4 mbar. This was evaluated as a suitable device for ships of 1800kW because the back pressure in all boundary conditions did not exceed the classification standard of 68mbar.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.439-446
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• 2009

Nitrogen balance in the regional scale which was calculated the difference between nitrogen input and output was estimated to assess the impact of rice cultivation on water environment. Nitrogen balances in Gyeonggi province, where nitrogen concentration in irrigation water was high and in Chungnam province, where nitrogen absorbtion by rice was high, were -5.4 and -8.3 kg $-8.3kg\;ha^{-1}\;yr^{-1}$, respectively. Nitrogen balances of paddy field in Gangwon province, where nitrogen output was small and irrigation water was clean, and in Gyeongnam province, where organic matter content of soil was high and rice yield was low, were 4.9 and $14.0kg\;ha^{-1}\;yr^{-1}$, respectively. Average nitrogen balance and total nitrogen absorption of paddy field in Korea were estimated to $-0.3kg\;ha^{-1}\;yr^{-1}$ and $-3,315Mg\;yr^{-1}$, respectively. When the nitrogen concentration in irrigation water was increased by $1mg \;L^{-1}$, nitrogen balance of rice paddy changed by $-2.91kg\;ha^{-1}\;yr^{-1}$. Also, when nitrogen fertilizer applied was decreased from 110 to $90kg\;ha^{-1}$ and the same harvest was maintained, the nitrogen absorption by rice paddy from irrigation water was estimated to increase by 10,600 Mg per year in Korea. However, in cases, the harvest was reduced to either 90% or 85%, nitrogen balances were changed from -11.7 to -2.3 and $2.4kg\;ha^{-1}$, respectively. These results suggest that the reduction of nitrogen fertilizer use may not always lead to a negative nitrogen balance and sustainable agriculture can achieve by not cutting down the use of fertilizer only but by reduction of fertilizer application concurrently by maintenance of harvest and by utilization of environmental characteristics such as nutrient contents in irrigation water and soils.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.474-480
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• 2016

In this study, formation background of biodiversity and its changes in the process of geologic history, and effects of climate change on biodiversity and human were discussed and the alternatives to reduce the effects of climate change were suggested. Biodiversity is 'the variety of life' and refers collectively to variation at all levels of biological organization. That is, biodiversity encompasses the genes, species and ecosystems and their interactions. It provides the basis for ecosystems and the services on which all people fundamentally depend. Nevertheless, today, biodiversity is increasingly threatened, usually as the result of human activity. Diverse organisms on earth, which are estimated as 10 to 30 million species, are the result of adaptation and evolution to various environments through long history of four billion years since the birth of life. Countlessly many organisms composing biodiversity have specific characteristics, respectively and are interrelated with each other through diverse relationship. Environment of the earth, on which we live, has also created for long years through extensive relationship and interaction of those organisms. We mankind also live through interrelationship with the other organisms as an organism. The man cannot lives without the other organisms around him. Even though so, human beings accelerate mean extinction rate about 1,000 times compared with that of the past for recent several years. We have to conserve biodiversity for plentiful life of our future generation and are responsible for sustainable use of biodiversity. Korea has achieved faster economic growth than any other countries in the world. On the other hand, Korea had hold originally rich biodiversity as it is not only a peninsula country stretched lengthily from north to south but also three sides are surrounded by sea. But they disappeared increasingly in the process of fast economic growth. Korean people have created specific Korean culture by coexistence with nature through a long history of agriculture, forestry, and fishery. But in recent years, the relationship between Korean and nature became far in the processes of introduction of western culture and development of science and technology and specific natural feature born from harmonious combination between nature and culture disappears more and more. Population of Korea is expected to be reduced as contrasted with world population growing continuously. At this time, we need to restore biodiversity damaged in the processes of rapid population growth and economic development in concert with recovery of natural ecosystem due to population decrease. There were grand extinction events of five times since the birth of life on the earth. Modern extinction is very rapid and human activity is major causal factor. In these respects, it is distinguished from the past one. Climate change is real. Biodiversity is very vulnerable to climate change. If organisms did not find a survival method such as 'adaptation through evolution', 'movement to the other place where they can exist', and so on in the changed environment, they would extinct. In this respect, if climate change is continued, biodiversity should be damaged greatly. Furthermore, climate change would also influence on human life and socio-economic environment through change of biodiversity. Therefore, we need to grasp the effects that climate change influences on biodiversity more actively and further to prepare the alternatives to reduce the damage. Change of phenology, change of distribution range including vegetation shift, disharmony of interaction among organisms, reduction of reproduction and growth rates due to odd food chain, degradation of coral reef, and so on are emerged as the effects of climate change on biodiversity. Expansion of infectious disease, reduction of food production, change of cultivation range of crops, change of fishing ground and time, and so on appear as the effects on human. To solve climate change problem, first of all, we need to mitigate climate change by reducing discharge of warming gases. But even though we now stop discharge of warming gases, climate change is expected to be continued for the time being. In this respect, preparing adaptive strategy of climate change can be more realistic. Continuous monitoring to observe the effects of climate change on biodiversity and establishment of monitoring system have to be preceded over all others. Insurance of diverse ecological spaces where biodiversity can establish, assisted migration, and establishment of horizontal network from south to north and vertical one from lowland to upland ecological networks could be recommended as the alternatives to aid adaptation of biodiversity to the changing climate.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.907-913
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• 1997

Background : Congenital bronchoesophageal fistula(BEF) presented in adult life is a rare disorder and has characteristic clinical findings such as paroxysmal cough after water ingestion and recurrent respiratory infections. It usually manifested recurrent pneumonia and chronic cough with purulent phlegmon which was mis-or under-diagnosed as chronic bronchitis, bronchiectasis or lung abscess so forth. Methods : We reviewed retrospectively 13 cases of congenital BEF in adult of Paik Hospital, College of Medicine, Inje University including 22 cases of congenital BEF previously reported in literature of Korea from 1979 through 1995. Results : The mean age at diagnosis was $40.2{\pm}14.3$. There was no difference in sex ratio(Male : Female 18 : 17). The most common symptom was cough(91.4%), followed by chronic sputum(74.3), hemoptysis(25.7), and paroxysmal nocturnal cough at specific position(20%). Twenty one of 31 patients who were able to review have the most specific sign, Ono's sign presented as paroxysmal cough after liquid ingestion. By classification of Braimbridge-Keith, Fourteen(45.1%) of 31 patients were group I (associated with esophageal diverticulum), 15(48.4%) were group II (simple fistula), and group Ill and IV was one case in each. The opening of fistula confined to right lower lobe in 26(76.5%), left lower lobe in 6(17.6%), and left main bronchus in 2(5.9%) cases. Conclusion : Congenital bronchoesophageal fistula is uncommon disorder which has characteristic histories and specific symptoms such as chronic and recurrent lower respiratory infections, and paroxysmal cough after liquid ingestion. Medical attention and careful history should be done in patients who have localized recurrent lower respiratory infections in right lower lobe.

• Journal of Environmental Impact Assessment
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• v.25 no.5
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• pp.345-356
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• 2016

In this study, auto-calibration method for water quality model was compared and analyzed using QUAL2Kw, which can estimate the optimum parameters through the integration of genetic algorithm and QUAL2K. The QUAL2Kw was applied to the Sum River which is greatly affected by the pollution loads of Wonju city. Two auto-calibration methods were examined: single parameter application for the whole river reach and separate parameter application for each reach of multiple reaches. The analysis about CV(RMSE) and fitness of the GA show that the separate parameter auto-calibration method is better than the single parameter method in the degree of precision. Thus the separate parameter auto-calibration method is applied to the water quality modelling of this study. The calibrated QUAL2Kw was used for the three scenarios for the water quality management of the Sum River, and the water quality impact on the river was analyzed. In scenario 1, which improve the effluent water quality of Wonju WWTP, BOD and TP concentrations of the Sum River 4-1 station which is representative one of Mid-Watershed, are decreased 17.7% and 29.1%, respectively. And immediately after joining the Wonjucheon, BOD and TP concentrations are decreased 50.4% and 40.5%, respectively. In scenario 2, Wonju water supply intake is closed and multi-regional water supply, which come from other watershed except the Sum River, is provided. The Sum River water quality in scenario 2 is slightly improved as the flow of the river is increased. Immediately after joining the Wonjucheon, BOD and TP concentrations are decreased 0.18mg/L and 0.0063mg/L, respectively. In scenario 3, the water quality management alternatives of scenario 1 and 2 are planned simultaneously, the Sum River water quality is slightly more improved than scenario 1. Water quality prediction of the three scenarios indicates that effluent water quality improvement of Wonju WWTP is the most efficient alternative in water quality management of the Sum River. Particularly the Sum River water quality immediately after joining the Wonjucheon is greatly improved. When Wonju water supply intake is closed and multi-regional water supply is provided, the Sum River water quality is slightly improved.

• Journal of Nutrition and Health
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• v.50 no.2
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• pp.180-191
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• 2017

Purpose: The purpose of the study was to identify teacher's knowledge about sodium, dietary behaviors related to sodium, attitudes towards a low-salt diet, and meal attitude guidance as well as examine the relationship between these variables. Methods: The participants were 351 teachers at an elementary school in the Jeonbuk area. The data were analyzed using ANOVA, Duncan test, and Pearson correlation coefficients with SPSS v. 20.0. Results: The score for teachers' knowledge about sodium was 12.92 points of a possible 16, the score for dietary behavior related to sodium was 46.85 points of a possible 70, and the score for attitude towards a low-salt diet was 33.63 points of a possible 50. Their score for meal attitude guidance was 59.95 points of a possible 80. The knowledge showed significant differences by hypertension drug (p < 0.05) and stress level (p < 0.05). The dietary behavior of sodium use showed significant differences by gender (p < 0.01), work experience (p < 0.05), BMI (p < 0.01), drinking (p < 0.05), concern about health (p < 0.05), and stress level (p < 0.05). The attitude towards a low-salt diet showed significant differences by gender (p < 0.05), marital status (p < 0.05), work experience (p < 0.05), drinking (p < 0.05), concern about health (p < 0.001), and stress level (p < 0.05). Meal attitude guidance showed a significant difference by marital status (p < 0.001), age (p < 0.001), work experience (p < 0.001), drinking (p < 0.01), regularity of health checkup (p < 0.001), concern about health (p < 0.001), and stress level (p < 0.05). There was a low positive correlation between knowledge about sodium and dietary behavior related to sodium as well as between dietary behavior related to sodium and attitudes towards a low-salt diet. Attitudes towards a low-salt diet showed a positive correlation with meal attitude guidance. Conclusion: Therefore, it is necessary to consider educational programs on increasing knowledge and attitudes towards a low-salt diet in teachers for improvement of meal attitude guidance activities for students.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.298-303
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• 2007

Antithrombotic activities of water extract of cheongkookjang and cheongkookjang fermented with green tea or mugwort were evaluated on some antithrombosis related activities in vitro and thrombotic death inhibition in vivo. Cheongkookjang made of white soybean (Glycine max) or black small soybean (Rhynchosia nulubilis) showed potent antioxidative activities. Addition of green tea or mugwort during cheongkookjang fermentation increased the antioxidative activity, cheongkookjang with green tea showed more drastic increase compared with cheongkookjang with mugwort. Nitrite scavenging effects of the cheongkookjang extracts were prominent but the addition of green tea or mugwort seldom increased the scavenging effects. All the cheongkookjang extracts showed strong inhibitory activities on platelet aggregation. The inhibitory activities of cheongkookjang were increased considerably by addition of green tea or mugwort even with low concentration. Plasmin unit as fibrinolytic activity was not affected considerably by addition of green tea. Addition of mugwort decreased the activity transiently at low concentration ($0.3{\sim}1.0%$) but increased again slowly at higher concentration ($1{\sim}3%$). In vitro thrombotic death inhibition test, the antithrombotic activity of cheongkookjang made of black small bean with green tea was higher by about 1.5 times compared to that without green tea. As results, cheongkookjang might inhibit antithrombosis not only by fibrinolytic action but also by inhibition of platelet aggregation and antioxidative action. The addition of functional materials such as green tea or mugwort could increase the antithrombotic function, even at low concentration.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.374-381
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• 2015

Occurrences of coastal dredged materials are ever increasing due to port construction, navigational course maintenance and dredging of polluted coastal sediments. Ocean dumping of the coastal dredged materials has become virtually prohibited as London Treaty will be enacted as of the year 2012. It will be necessary to treat and recycle the dredged materials that may carry organic pollutants and heavy metals in a reasonable and effective process: collection of the dredged materials, liquid and solid separation, and treatment of organic compounds and heavy metals. In this study we have developed a continuous bioreactor system that can treat a mixture of silt and particulate organic matter using a microbial consortium (BM-S-1). The steady-state operation conditions were: pH (7.4-7.5), temperature ($16^{\circ}C$), DO (7.5-7.9), and salt concentration (3.4-3.7%). The treatment efficiencies of SCOD, T-N and T-P of the mixture were 95-96%, 92-99%, and 79-97%. The system was also effective in removal of heavy metals such as Zn, Ni, and Cr. Levels of MLSS during three months operation period were 11,000-19,000 mg/L. Interestingly, there was little sludge generated during this period of operation. The augmented microbial consortium seemed to be quite active in the removal of the organic component (30%) present in the dredged material in association with indigenous bacteria. The dominant phyla in the treatment processes were Proteobacteria and Bacteroidetes while dominant genii were Marinobacterium, Flaviramulus, Formosa, Alteromonadaceae_uc, Flavobacteriaceae_uc. These results will contribute to a development of a successful bioremediation technology for various coastal and river sediments with a high content of organic matter, inorganic nutrients and heavy metals, leading to a successful reuse of the polluted dredged sediments.