• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.638-646
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• 2014

The effect of in-organic chelating agents with Fe(II) and Fe(III) in modified Fenton was evaluated to degradation BTEX (benzene, toluene, ethylbenzene, xylene). Citric acid and pyrophosphate were used in experimentals and an optimum chelating agent for BTEX degradation was determined. In $H_2O_2$/Fe(III)/citric acid, degradation of BTEX was decreased when concentration of citric acid was increased. In $H_2O_2$/Fe(III)/pyrophosphate, degradation of BTEX was increased when concentration of pyrophosphate was increased and degradation for BTEX was relatively high compared with $H_2O_2$/Fe(III)/citric acid. In $H_2O_2$/Fe(II)/chelating agents, degradation for BTEX was high and pH variation was minimized when molar ratio of Fe(II) and citric acid was 1:1. Optimum molar concentration of Fe(II), citric acid and $H_2O_2$ were 7 mM, 7mM and 500 mM for degradation of 100 mg/L of benzene to obtain best efficiency of $H_2O_2$, least precipitation of iron and best degradation.

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.65-75
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• 2001

This study purpose to elucidate the characteristics of water quality by elevation and groundwater samples has been studied with the samples from 150 selected groundwater represented the watershed of groundwater wells in Cheju Island. The evaluation of the characteristics of water quality utilized the physical and chemical property and the statistical analysis. According to the piper diagram, groundwater in the under 50 m region is shown N $a^{+}$＋ $K^{+}$-C $l^{[-10]}$ type, and that groundwater in the 50~100 m region is shown N $a^{+}$＋ $K^{+}$-HC $O_3$$^{[-10]}$ ＋C $O_3$$^{2-}$ type. and partly N $a^{+}$＋ $K^{+}$-C $l^{[-10]}$ type. In the above 100 m region belongs to N $a^{+}$＋ $K^{+}$-HC $O_3$$^{[-10]}$ ＋C $O_3$$^{2-}$ type. The result of factor analysis, commonly two factors as TDS(Total Dissolved Solid) and the contaminants extracted in the under 50m region and above 100 m region. Three factors were obtained from the result of the factor analysis in the 50~100 m region. Factor 1, consisting of TRS content. Factor 2, consisting of the contaminant and the dissolution of minerals. and Factor 3, consisting of HC $O_3$$^{[-10]}$ content. content.

• Membrane Journal
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• v.17 no.2
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• pp.124-133
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• 2007

In this study, we treated lake water by 2 kinds of multichannel ceramic micro filtration membranes. We could investigate effects of $N_2-back-flushing$ time (BT) and transmembrane pressure (TMP), and find optimal operating conditions. The BT were changed in $10{\sim}60$ sec, TMP in $0.6{\sim}2.0$ bar at fixed filtration time (FT) 8 min, flow rate 2.0 L/min and back-flushing pressure 2.0 bar. Also, the optimal conditions were discussed in the viewpoints of resistance of membrane fouling $(R_f)$, dimensionless permeate flux $(J/J_o)$, permeate flux (J) and total permeate volume $(V_T)$. As result, optimal back-flushing conditions for HC04 ($0.4{\mu}m$ pore size) and HC10 membrane $(1.0{\mu}m)$ were BT=10 sec and BT=20 sec, respectively. Then, higher TMP should increase the driving force, and could produce more VT. Average rejection rates of pollutants were higher than 95.4% for turbidity, $12.7{\sim}20.1%\;for\;COD_{Mn},\;0.0{\sim}6.4%\;for\;NH_3-N,\;1.9{\sim}4.6%$ for T-N and $34.9{\sim}88.4%$ for T-P.

• Korean Journal of Microbiology
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• v.32 no.3
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• pp.238-244
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• 1994

To investigate the bacterial potentials for utilizing dissolved organic matter in highly eutrophic estuary, the annual fluctuations of microbiological and physicochemical environmental parameters were analyzed in Naktong River Estuary. Total bacterial number ranged from 0.33 to $2.09{\times}10^7$ cells/ml, and correlated with the heterotrophic bacterial numbers in more eutrophic sites, especially. Bacterial biovolume and biomass varied between 0.064 and 0.156 2.09${\mu}m^3$/cell, 0.163 and 1.036 ${\mu}g$-C/ml, respectively. Bacterial secondary productivity ranged from 0.24 to 60.86 ${\mu}g$-C/l/h, and showed high correlations with the environmental parameters of pollution indicator. The seasonal variation pattern of bacterial productivity in freshwater sites was high in winter and low in summer, which was interpreted as the results of pollution loads varied with the amount of rainfall. In seawater site, the pattern was different from those of freshwater sites; high in summer and low in winter. In this site, the values of bacterial productivity showed positive correaltions with chlorophyll a, heterotrophic bacterial number, and temperature (r>0.5, p<0.05). These results suggested that the main source of organic matter which influences the bacterial productivity may be allochthonous materials in the upper freshwater zone of Naktong River Barrage, and autochthonous algal excretory products in the lower seawater zone of Naktong River Barrage.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.97-105
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• 2008

Nitrogen budgets in Korea in 2005 were estimated using a mass balance approach. Major nitrogen fluxes were divided into three sections: cities, agricultural area, and forest. Nitrogen inputs were chemical and biological fixation, dry and wet deposition, imported food and feed, while crop uptake, volatilization, denitrification, leaching, runoff, and forest consumption were nitrogen outputs. Non-point source(NPS) pollution budgets were also estimated by mass balance approach. Annual total nitrogen inputs budgets were 1,442,254 ton$\cdot$yr$^{-1}$, and outputs were 814,415 ton$\cdot$yr$^{-1}$. Approximately 19.4% of nitrogen input leaked to river and seawater as NPS pollution. It contains nitrogen input 21 percent more than the previous research in 2002. Especially the change of government plans affect nitrogen budget. As a result, in the output field, the whole nitrogen amount due to landfill reduce from 20 percent to less than 1 percent.

• Ocean and Polar Research
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• v.34 no.2
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• pp.151-163
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• 2012

Digestive cells of the bivalves have a highly developed lysosomal system and the system is known to be sensitive to changes in environmental qualities. In this study, we measured lysosomal responses of the digestive cells in wild oyster, Crassostrea gigas using frozen section. Oysters were collected in June 2010 from intertidal areas in the inner and outer bay of Gwangyang off the south coast of Korea. From the tissue sections, we measured the digestive cell lysosomal membrane stability (LMS), level of neutral lipids (NL), lipofuscin (LF) and the digestive gland atrophy (DGA). The DGA and condition index of oysters from the inner bay were significantly lower (P<0.05). The statistical test indicated that LMS levels of oysters in the inner bay and the outer bay were not significantly different since a shorter activity was displayed by oysters from the inner bay than that of oysters in outer bay. The LF deposition level of the oysters in the inner bay displayed significantly higher levels than the outer bay (P<0.05). In contrast, the NL accumulation measured from oysters in outer bay was significantly higher than the level observed in the inner bay (P<0.05). Different levels of DGA and LF that were observed in the inner and outer bays were thought to be associated to different level of environmental contamination and these two assays are considered to be good biomarkers.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.06a
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• pp.91-120
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• 1996

경제발전과 더불어 산업의 많은 분야에서 순수 및 초순순의 사용이 증가하고 있으나, 환경오염에 의한 원수의 오염에 따라 순수 및 초순순제조의 장치비와 처리비용의 증가가 야기되고 있다. 현재 국내에는 화력, 원자력발전소를 비롯하여 열병합발전소, 석유화학공장, 제약회사, 전기 전자부품회사, 반도체회사 및 철강회사 등 많은 분야에서 순수 및 초순수 제조장치의 구성과 성능이 많은 차이를 나타내고 있다. 국내의 초순수 제조장치는 90% 이상이 이온교환수지를 사용하는 이온교환법과 UF, R/O System과 같은 Membrane을 사용하는 Membrane System을 병행하여 적용하고 있다. 국내 초순수처리 Plant에서는 통상 전처리 System과 1차 순수제조 System 및 초순수 System이 상호 연결되어 Plant가 구성 운영되고 있다. 전처리 System에는 응집침전, 여과 흡착, 살균 등이 적용되고 있으며 여과 System에 Membrane을 적용할 수 있으나 국내에서는 특별한 경우를 제외하고 대부분 전처리 여과 System에 Media Filter를 사용한다. 전처리 System도 순수처리 장치의 전처리로는 없어서는 안되는 System이지만 여기에는 전처리 System을 제외하고 국내에서 적용하고 있는 초순수처리 System의 공정현황과 각 System별 특징을 설명하고 있다. 초순순 System에는 요구 수질에 따라 다소 차이가 있지만 반도체 공업에서 사용되는 초순수 System이 이중 최고의 Grade로 반도체공업에서 적용되고 있는 System을 기준하였다. 특히 Membrane을 적용한 초순수제조 System이 증가하고 있어 R/O, ED, EDR, CDI, (EDI)와 같은 Membrane System의 특성과 원리를 검토하였다.대적으로 높은 산소확산계수와 물에 대해서는 낮은 투과도를 가져야 한다. 높은 산소확산계수는 반응을 빠르게 하는 잇점이 있으며 물에 대한 낮은 투과도는 센서내의 전해질 물질을 유지보호하는 역할을 한다. 분리막이 산소전극에 이용될 경우 높은 산소 확산계수 이외에도 적절한 기계적 강도, 열적 안정성 등이 요구된다. 몰입이 가능하여 임계치가 저하된 것으로 여겨진다. 또한 광학적 이득의 존재는 이 구조에 의한 극단파장 반도체 레이저다이오드의 실현 가능성을 나타내는 것이다.548 mL에 비해 통계학적으로 의의 있게 적었다(p<0.05). 결론: 관상동맥우회로 조성수술에서 전방온혈심정지액을 사용할 때 희석되지 많은 고농도 포타슘은 fliud overload와 수혈을 피하고 delivery kit를 사용하지 않음으로써 효과적이고 만족할 만한 심근보호 효과를 보였다.를 보였다.4주까지에서는 비교적 폐포는 정상적 구조를 유지하면서 부분적으로 소폐동맥 중막의 비후와 간질에 호산구 침윤의 소견이 특징적으로 관찰되었다. 결론: 분리 폐 관류는 정맥주입 방법에 비해 고농도의 cisplatin 투여로 인한 다른 장기에서의 농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.303-311
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• 2015

To determine the concentrations of selected 10 perfluorinated compounds (PFCs), a field study was conducted in the water body of Yeongsan River Water System. Raw water samples were collected in the spring and the fall, respectively, which included 18 sampling sites. Collected samples were equally mixed and then served as an analytical sample. The concentration of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) were in range of 20.80-92.0 ng/L and ND-28.40 ng/L respectively. Perfluorononanoate (PFNA) and perfluorohexanesulfonate (PFHxS) were ranged from ND to 42.20 ng/L and from ND to 11.47 ng/L. The detection frequencies of other PFCs selected in this study were very sparse at very low concentrations, except for PFOS, PFOA, PFNA and PFHxS. PFOS was higher detection frequency and concentration in both spring and fall, PFOA and PFNA were in spring, and PFHxS was in fall. As a result, the observed concentrations of PFCs in the downtown water area of Gwangju, located in the wastewater treatment plants, were relatively higher than other sampling points.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.51-67
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• 2002

In order to understand behaviors of heavy metals around the artificial Lake Shihwa in the vicinity of Kyunggi Bay in Korea in relation with huge environmental changes due to construction of huge artificial lake, water samples were collected from Lake Shihwa and its tributaries from 1996 to 1998 and analyzed. Due to extreme pollutant discharge from various kinds of anthropogenic sources such as the Banweol and Shihwa Industrial Complexes and cities, the Shihwa and its tributaries have been polluted in waters with various heavy metals. The enrichment factors of particulate heavy metals in water of streams and storm sewers were very high. All of the heavy metals observed in the waters showed relatively high temporal and spatial variations. In surface waters of the lake during the desalination after the dike establishment, spatial distributions of heavy metal concentrations were mainly controlled by various biogeochemical factors as well as input of industrial and municipal wastewaters, while, physical mixing was minor factor Pb and Co showed a strong affinity to particle phase, however the affinity to dissolved phase was dominated in Ni, Cu and Cd. Water quality of the artificial Lake Shihwa has been deteriorated by direct discharge of untreated wastewater and heavy metals have been accumulated in the lake system. Therefore, luther environmental improvement plan should be programmed subsequently.

• Journal of Soil and Groundwater Environment
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• v.13 no.3
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• pp.52-58
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• 2008

Mn-impregnated activated carbon (Mn-AC) prepared at different conditions was applied in the treatment of synthetic wastewater containing both organic and inorganic contaminants. Phenol and As(III) was used as the representative organic and inorganic contaminants, respectively. After evaluation of the physicochemical characteristic and stability of Mn-AC, oxidation of As(III) as well as adsorption of phenol by activated carbon(AC) and Mn-AC were investigated in a batch reactor. To investigate the stability of Mn-AC, dissolution of Mn from each Mn-AC was measured pH ranging from 2 to 4. Although Mn-AC was unstable at a strong acidic condition, the dissoluted Mn was below 3 ppm at pH 4. XRD analysis of Mn-AC indicated that the mineral type of the impregnated manganese was $Mn_2O_3$. From the simultaneous treatment of As(III) and phenol by AC and Mn-AC, As(III) oxidation by Mn-AC was greater than that by AC at lower pH, while the reverse order was observed at higher pH. After impregnation of Mn onto AC, 13% decrease of the surface area was observed, causing 8% reduction of phenol removal. Considering removal properties of As(III) and phenol, Mn-AC could be applied in the simultaneous treatment of wastewater contaminated with multi-contaminants.