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Incheon, South Korea

Lee H.-J.,Chonnam National University | Hong M.-K.,Korea Environment Corporation | Moon S.-H.,Gwangju Institute of Science and Technology

Interests on the polarity reversal have increased to prevent or minimize membrane fouling and scaling during the operation of electromembrane processes. In this study, the influence of the operation conditions on the process efficiency was investigated in the electrodeionization reversal (EDIR) system with an electrodeionization with the polarity reversal. The removal efficiencies of divalent cations (Mg 2+ and Ca 2+) kept high value without scale formation on the membrane surface. Through the EDIR operation, the process performance was affected by polarity reversal periods, and the operating polarity reversal period was determined to 40min or shorter in this study.In the long term EDIR experiments with different cation exchange membranes, the homogeneous membranes showed marginally higher removal efficiency compared to the heterogeneous membrane. The scale powders and the surface of scaled membrane were analyzed using electron microscopes and it was observed that the scales formed as carbonate of divalent cations. The EDIR results showed the feasibility of the EDIR system for use in water softening process without significant scale formation even in a relatively high concentration. © 2011 Elsevier B.V.. Source

Park S.,Gwangju Institute of Science and Technology | Yasin M.,Gwangju Institute of Science and Technology | Kim D.,Korea Institute of Energy Research | Park H.-D.,Korea University | And 3 more authors.
Journal of Industrial Microbiology and Biotechnology

A gas-lift reactor having a high mass transfer coefficient (k L a = 80.28 h-1) for a relatively insoluble gas (carbon monoxide; CO) was used to enrich (homo)acetogens from animal feces. Samples of fecal matter from cow, rabbit, chicken, and goat were used as sources of inoculum for the enrichment of CO and H2 utilizing microbial consortia. To confirm the successful enrichment, the Hungate roll tube technique was employed to count and then isolate putative CO utilizers. The results of this work showed that CO and H2 utilizing consortia were established for each inoculum source after 8 days. The number of colony-forming units in cow, rabbit, chicken, and goat fecal samples were 3.83 × 109, 1.03 × 10 9, 8.3 × 108, and 3.25 × 108 cells/ml, respectively. Forty-two colonies from the animal fecal samples were screened for the ability to utilize CO/H2. Ten of these 42 colonies were capable of utilizing CO/H2. Five isolates from cow feces (samples 5, 6, 8, 16, and 22) were highly similar to previously unknown (homo)acetogen, while cow-7 has shown 99 % similarity with Acetobacterium sp. as acetogens. On the other hand, four isolates from chicken feces (samples 3, 8, 10, and 11) have also shown high CO/H2 utilizing activity. Hence, it is expected that this research could be used as the basis for the rapid enrichment of (homo)acetogenic consortia from various environmental sources. © 2013 Society for Industrial Microbiology and Biotechnology. Source

Eom S.-Y.,Chungbuk National University | Yim D.-H.,Chungbuk National University | Lee C.-H.,Korea Environment Corporation | Choe K.-H.,Chungbuk National University | And 4 more authors.

Background Few studies in epidemiology have evaluated the effects of gene-environment interaction on oxidative stress, even though this interaction is an important etiologic factor in lung carcinogenesis. We investigated the effects of the genetic polymorphisms of paraoxonase 1 (PON1), smoking, and the interaction between the two on lung cancer risk and oxidative stress. Methods This study's subjects consisted of 416 newly diagnosed lung cancer patients and an equal number of matched controls. The GoldenGate assay was used for genotypic analyses of the PON1 gene. Urinary 8-hydroxydeoxyguanosine (8-OHdG) and thiobarbituric acid reactive substances levels were measured as indicators of oxidative stress. Results The PON1 rs662 AA genotype showed a significantly lower risk of lung cancer than the GG genotype (OR = 0.60, 95% CI: 0.36-0.99). The protective effect of the PON1 rs662 AA genotype on lung cancer risk was limited to non-smokers. Lung cancer patients who had the rs662 A allele showed a dose-dependent association between smoking status and oxidative stress markers. Among non-smoking lung cancer patients, urinary 8-OHdG levels were significantly lower in individuals with the rs662 GA and AA genotypes than in those with the GG genotype. Furthermore, we found a significant interaction effect between PON1 rs662 and smoking status on urinary 8-OHdG levels in lung cancer patients. Conclusions Our results suggest that the protective effect of PON1 rs662 SNP against lung carcinogenesis and the induction of oxidative stress might be modulated by the interaction between PON1 genetic polymorphisms and tobacco smoking. © 2015 Eom et al. Source

Park S.-S.,77 Yongbong Ro | Kim J.-H.,77 Yongbong Ro | Kim J.-H.,Korea Environment Corporation
Atmospheric Environment

To examine the formation pathways of two size-resolved water-soluble organic carbon (WSOC) fractions, a total of 16 sets of size-segregated aerosol samples were collected using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) at a roadway site in Korea from September 29 to October 29, 2010. A XAD7HP (non-ionic aliphatic acrylic polymer) resin column was used to separate the filtered extracts into hydrophilic (WSOCHPI) and hydrophobic (WSOCHPO) WSOC fractions. Also the size distributions of water-soluble inorganic species and oxalate were examined to determine the formation pathways of size-resolved WSOCHPI and WSOCHPO fractions.The size distribution of WSOCHPI showed a dominant mode at 0.55μm, while the WSOCHPO had dominant modes at both 0.17-0.32μm and 0.55μm. On the basis of the size distribution characteristics, it was found that the formation pathways of both WSOCHPI and WSOCHPO were dependent on the particle size; in the condensation mode (0.17-0.32μm), both the WSOCHPI and WSOCHPO could be produced through atmospheric processes similar to those of SO42- and oxalate, which were derived from the gas-phase oxidations of organic compounds. In the droplet mode (0.55-1.8μm), the cloud processing of both the organic compounds and biomass burning emissions could be a major pathway for the WSOCHPI formation. However, the droplet mode WSOCHPO was likely produced through cloud processing and heterogeneous reactions or aerosol-phase reactions. In the coarse mode (>3.1μm), the WSOCHPI formation was more likely associated with soil-related particles (Ca(NO3)2 and CaSO4) than with sea-salt particles (NaNO3 and Na2SO4). © 2014 Elsevier Ltd. Source

Korea Environment Corporation, Electronics and Telecommunications Research Institute | Date: 2012-01-23

An apparatus and method are provided, which predict total nitrogen using general water quality data measured in real time. The total nitrogen prediction apparatus may include a regression model selection unit to select a regression model comprising general data of at least one water quality based on a correlation coefficient of the general data of at least one water quality, a quality-of-fit evaluation unit to evaluate quality of fit of the selected regression model, a regression model change unit to determine whether to change the regression model based on the quality of fit and change the regression model according to the determination result, and a total nitrogen prediction unit to predict total nitrogen of a body of water based on the regression model.

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