• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.17-22
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• 2010

The aim of this study is to research applicable possibility of DSI (Dry Sorbent Injection) technique in $SO_2$ removal process using lab-scale facility based on 500MW in capacity coal-fired thermal power plant operated by South Korea N. Power Co., Ltd. To increase the $SO_2$ removal efficiency, it is considered the mixing enhancement as different shapes called lobed-plate and stepplate tested ultimately for optimum shape. Also it tested to analysis $SO_2$ removal efficiency by numbers of injection holes. At experimental it showed the $SO_2$ removal efficiency is higher using mixing enhancement than not installed mixing enhancement and case on the step-plate was shown the most $SO_2$ removal efficiency. Also, $SO_2$ removal efficiency was higher recording which will increase the injection holes case on not installed mixing enhancement. But, the $SO_2$ removal efficiency was higher 4 injection holes case on installed mixing enhancement.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.214-217
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• 2001

자연계에서는 오염물질이 단일물질로 존재하기보다는 혼합물로 존재하는 것이 대부분이다. 본 연구에서는 지하수 오염물질 chlorinated aliphatic hydrocarbon(CAH)들 중 trichloroethylene(TCE), vinyl chloride(VC)에 대해서 Fe$^{\circ}$와 함께 미생물, 활성탄을 이용하여 단일물질 및 혼합물질상태에서 그 분해특성을 살펴보았다. 실험은 120$m\ell$ serum bottle을 이용하여 단일물질 및 혼합물질상태에서 그 분해특성을 살펴보았다. 실험은 120$m\ell$ serum bottle을 이용하였고 headspace 50${\mu}\ell$를 GC에 주입하여 각 오염물질 농도를 분석하였으며, Fe$^{\circ}$, Fe$^{\circ}$+ cell, Fe$^{\circ}$+ 활성탄 3가지 조건에서 TCE (25${\mu}\ell$)가 단일화합물 또는 VC(10$\mu\textrm{m}$)와 혼합화학물로 존재시 분해특성을 조사하였다. 단일화합물로 존재시 2시간후 TCE농도 측정 결과 Fe$^{\circ}$만을 이용하였을 때보다 활성탄, Cell을 함께 이용하였을 경우 그 분해율이 각각 1.6배, 1.8배 높게 나타났다. 그러나, VC와 혼화합물로 존재시 TCE 분해율은 단일 화합물로 존재시와 비교 Fe$^{\circ}$, Fe$^{\circ}$+ 활성탄, Fe$^{\circ}$+ cell 조건에서 각각 63%, 28%, 5%로 나타났다. VC는 Fe$^{\circ}$만으로는 분해가 되지 않았지만 cell에 의해 완전분해 되었으며, 함께 존재시 TC는 Fe$^{\circ}$만으로는 분해가 되지 않았지만 cell에 의해 완전분해 되었으며, 함께 존재시 TCE분해에 저해작용을 미치는 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.24-37
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• 2007

The Korean Ministry of Environment started controlling indoor air quality (IAQ) in 2004 through the introduction of a law regulating the use of pollutant emitting building materials. The use of materials with formaldehyde emission levels above $1.25 mg/m^2{\cdot}h$ (JIS A 1901, small chamber method) has been prohibited. This level is equivalent to the $E_2$ grade ($>5.0mg/{\ell}$) of the desiccator method (JIS A 1460). However, the $20{\ell}$ small chamber method requires a 7-day test time to obtain the formaldehyde and volatile organic compound (VOC) emission results from solid building interior materials. As a approach to significantly reduce the test time, the field and laboratory emission cell (FLEC) has been proposed in Europe with a total test time less than one hour. This paper assesses the reproducibility of testing formaldehyde and TVOC emissions from wood-based composites such as medium density fiberboard (MDF), laminate flooring, and engineered flooring using three methods: desiccator, perforator and FLEC. According to the desiccator and perforator standards, the formaldehyde emission level of each flooring was ${\le}E_1$ grade. The formaldehyde emission of MDF was $3.48 mg/{\ell}$ by the desiccator method and 8.57 g/100 g by the perforator method. To determine the formaldehyde emission, the peak areas of each wood-based composite were calculated from aldehyde chromatograms obtained using the FLEC method. Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and benzaldehyde were detected as aldehyde compounds. The experimental results indicated that MDF emitted chloroform, benzene, trichloroethylene, toluene, ethylbenzene, m,p-xy-lene, styrene, and o-xylene. MDF emitted significantly greater amounts of VOCs than the floorings did.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.2
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• pp.150-164
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• 2000

This study was conducted at occupational health laboratories in Seoul and Gyunggi district area from December, 1999 to January, 2000. The main purpose of this study was to survey the actual condition of safety and health by questionnaire and checklist and to assess the performance of fume hoods and the airborne exposures to chemicals in the laboratories. The chemicals in the cabinet were not classified by hazardous properties and the compressed gases were not stored safely. The prevalences of laboratories having first aid kits, fire extinguishers, and safety showers were found to be 18%, 55%, and 9%, respectively. Most laboratory workers were not educated for safety and health. Also, there was no performance evaluation for hazards and risks. The fume hoods in laboratories had not been annually inspected by checklist and the face velocity had been checked more than one time in the previous year for only 18% of them. Five percent of fume hoods had the face velocity more than 4.0 m/sec and 17% had no capture performance. Detected organic solvents were methylenechloride, acetone, ethylbenzene, isopropanol, xylene, methylisobutylketone, trichloroethylene, and toluene. The concentrations of organic solvents were much less than the occupational exposure limits proposed by the Ministry of Labor in Korea. This study showed that the actual condition of safety and health was not appropriate for laboratory workers. It is recommended that laboratory workers should be educated for the treatment and storage of hazardous chemicals and compressed gases to improve the working environment of the occupational safety and health laboratories.

• KSBB Journal
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• v.16 no.6
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• pp.527-532
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• 2001

Trichlooethylene (TCE) has become a widespread contaminant in air, soil, and underground water due to extensive industrial used and improper disposals. Since TCE is a suspected carcinogen and constitutes public health concerns, many treatment systems have been investigated to remove this hazardous waste. One of the most premising reactor systems for the treatment of TCE is trickling biofilter (TBF), in which monooxygenase (MO), the corresponding enzyme for initiating primary substrate oxidation, fortuitously degrades TCE via cometabolism. TCE, however, is not easily treated by simple TBF. This is mainly due to the toxicities of TCE and its degradation products to microbial film in TBF. In this paper, recent progresses on the development of bioreactor system for the treatment of TCE, especially gas-phase TCE, are reviewed. The potentials of novel biofilm reactor systems were also discussed for the long-term continuous treatment of TCE.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.96-102
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• 1994

Factors affecting non-proficient analytical ability were compared and evaluated by rating of laboratories and round. Analyst Indices between proficient and non-proficient participants were different. Coefficients of determination($R^2$) for standard of toluene, xylene and trichloroethylene of the 4th round between some proficient and non-proficient participants were significantly different(p<0.05). But, there was no difference in the 5th round. Average desorption efficiency of non-proficient participants was 88%-98%, which was lower than 96%-100% of some randomly selected proficient participants. Also non-proficient participants have a large variance of desorption efficiency, 11.79-19.69%. In the 5th round, desorption efficiency of metyl iso-butyl ketone(MIBK) reported by all participants was lower than 90% tested by NIOSH and especially low compared to other analytes. Participants evaluated to be non-proficient in the metal part have 85%-100.84% of average recovery, which was larger variance than 98% of some proficient participants. Although it is difficult to find quantitatively factors causing non-proficiency in analytical ability, pretreatement techniques and experience of analyst seems to be more important factors to produce accurate analytical result.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.482-492
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• 2012

Objectives: The main purpose of this study is to produce background data which can be compared with data on vulnerable areas such as industrial complexes in Ulsan, SihwaBanwol, Gwangyang, Yeosu, Pohang, Cheongju and Daesan in Korea. Methods: This study was performed on 1,007 local residents in Gangneung using personal questionnaires and medical check-up. Environmental pollutants including heavy metals in blood and urine were analyzed and the results are as follows. Results: According to the results of medical check-up, 705 subjects were "Normal (A and B)", 232 subjects were "Disease doubtful (R1)" and 70 subjects were "High blood pressure or Diabetes doubtful (R2)". Regarding geometric mean concentration, blood lead was 1.57 ${\mu}g/dL$, urine cadmium was 0.82 ${\mu}g/g-cr$, urine mercury was 0.98 ${\mu}g/g-cr$ and urine arsenic was 15.78 ${\mu}g/g-cr$. In the analysis of 11 kinds of VOCs in blood, vinyl chloride, 1,3-butadiene and dichloroethylene were not detected, while the detection rate of other chemicals was above 70% except chloroform(49.7%) and trichloroethylene(19.0%). In analysis of 16 kinds of PAHs in blood, 10 kinds showed more than 80% in detection rate. Also, detection rate of 4 kinds of PCBs in blood ranged 52 to 78%. Conclusions: Compared with industrial compelxes, the concentration of blood lead was lower, while urine cadmium and mercury levels were similar. Also, urine arsenic ranged at a significant level. Further study is required to find the cause of regional differences in concentrations of environmental pollutants.

• Journal of Environmental Health Sciences
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• v.36 no.4
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• pp.323-336
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• 2010

We evaluated the properties of a fixed-bed column reactor for high-concentration tetrachloroethylene (PCE) removal. The anaerobic bacterium Clostridium bifermentans DPH-1 was able to dechlorinate PCE to cis-1,2-dichloroethylene (cDCE) via trichloroethylene (TCE) at high rates in the monoculture biofilm of an upflow fixed-bed column reactor. The first-order reaction rate of C. bifermentans DPH-1 was relatively high at $0.006\;mg\;protein^{-1}{\cdot}l{\cdot}h^{-1}$, and comparable to rates obtained by others. When we gradually raised the influent PCE concentration from $30\;{\mu}M$ to $905\;{\mu}M$, the degree of PCE dechlorination rose to over 99% during the operation period of 2,000 h. In order to maintain efficiency of transformation of PCE in this reactor system, more than 6 h hydraulic retention time (HRT) is required. The maximum volumetric dechlorination rate of PCE was determined to be $1,100\;{\mu}mol{\cdot}d^{-1}l$ of reactor $volume^{-1}$, which is relatively high compared to rates reported previously. The results of this study indicate that the PCE removal performance of this fixed-bed reactor immobilized mono-culture is comparable to that of a fixed-bed reactor mixture culture system. Furthermore, our system has the major advantage of a rapid (5 days) start-up time for the reactor. The flow characteristics of this reactor are intermediate between those of the plug-flow and complete-mix systems. Biotransformation of PCE into innocuous compounds is desirable; however, unfortunately cDCE, which is itself toxic, was the main product of PCE dechlorination in this reactor system. In order to establish a system for complete detoxification of PCE, co-immobilization of C. bifermentans DPH-1 with other bacteria that degrade cDCE aerobically or anaerobically to ethene or ethane may be effective.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.40-46
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• 2005

Clostridium bifermentans strain DPH-1 has already been found to dechlorinate perchloroethylene (PCE) to cis-dichloroethylene (cis-DCE) via trichloroethylene (TCE). In this study, our investigation on different culture conditions of this DPH-1 strain was extended to find a more efficient and cost effective growth medium composition for this DPH-1 strain in bioremediation practices. Temperature dependency of strain DPH-1 showed that the growth starting time and PCE degradation at $15^{\circ}C$ was very slow compared to that of $30^{\circ}C$, but complete PCE degradation occurred in both cases. For the proper utilization of strain DPH-1 in more cost effective bioremediation practices, a simpler composition of an effective media was studied. One component of the culture medium, yeast extract, had been substituted by molasses, which served as a good source of electron donor. The DPH-1 strain in the medium containing molasses, in the presence of $K_{2}HPO_4\;and\;KH_{2}PO_4$, showed identical bacterial multiplication (0.135 mg protein $mL^{-1}h^{-1}$) and PCE degradation rates ($0.38\;{\mu}M/h$) to those of the yeast extract containing medium.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.892-899
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• 2005

Groundwater is naturally of excellent microbiological qualify and generally of adequate quality for drinking water use. However, recently, the impact of urbanization and intensification of agricultural production have led to serious deterioration in groundwater quality. The representative SOCs used in this study were trichloroethylene (TCE) and tetrachloroethylene (PCE). Powdered activated carbon (PAC) is widely used for SOCs removal. The overall goal of this study was to demonstrate the feasibility of using a hybrid use of PAC-UF and PAC-MF processes for treating groundwater contaminated with TCE and PCE. The results show that the flux decline rate was lower for the PAC-UF or PAC-MF process than for UF or MF only process. Therefore, applying PAC before UF or MF membrane filtration showed not only enhancing the removal of TCE and PCE, but also reducing membrane fouling.