• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.167-177
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• 2011

Billions of barrels of briny produced water are generated in the United States every year during oil and gas production. The first step toward recovering or reusing this water is to remove the hazardous organics dissolved in the briny produced water. Biological degradation of hazardous volatile compound could be possible regardless of salinity if they were extracted from briny water. In the current work, the effectiveness of a vapor phase biofilter to degrade the gas-phase contaminants (benzene, toluene, ethylbenzene and xylenes, BTEX) extracted from briny produced water was evaluated. The performance of biofilter system responded well to short periods when the BTEX feed to the biofilter was discontinued. To challenge the system further, the biofilter was subjected to periodic spikes in inlet BTEX concentration as would be expected when it is coupled to a Surfactant-Modified Zeolite (SMZ) bed. Results of these experiments indicate that although the BTEX removal efficiency declined under these conditions, it stabilized at 75% overall removal even when the biofilter was provided with BTEX-contaminated air only 8 hours out of every 24 hours. Benzene removal was found to be the most sensitive to time varying loading conditions. A passive, granular activated carbon bed was effective at attenuating and normalizing the peak BTEX loadings during SMZ regeneration over a range of VOC loads. Field testing of a SMZ bed coupled with an activated carbon buffering/biofilter column verified that this system could be used to remove and ultimately biodegrade the dissolved BTEX constituents in briny produced water.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.2
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• pp.120-124
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• 2014

This study was performed to compare the level of odorous compounds in feces and urine of finishing pigs. Feces and urine from 16 finishing pigs were separately collected for 28-d. Concentrations of volatile organic compound (VOC; phenols and indoles) and volatile fatty acid (VFA; SCFA and BCFA) were measured in feces and urine. Amount of phenols and p-cresol was higher (P<0.05) in urine than in feces. Urinal levels of phenols and p-cresol were 257.8 ppm and 250.9 ppm, and those of fecal phenols and p-cresol were 0.50 ppm and 0.05 ppm, respectively. There was no difference in concentration of indoles from feces (1.0 ppm) and urine (1.8 ppm). Short chain fatty acid (SCFA) level in urine was higher (P<0.05) than in feces showing 4,547 ppm and 863 ppm, respectively. Proportion of acetic acid to total SCFA was higher in urine (94%) than in feces (66%). However, level of branched fatty acid (BCFA) was greater in feces (118 ppm) compare to that of urine (87 ppm). Odorous compounds analyzed in the current study, phenols and SCFA, were contained more in urine than in feces. Greater amount of VFA is typically found in feces than in urine since it is generated in the large intestine. However, urine contained more VFA than feces in the current study. Therefore, it will be necessary to exploit odor reducing techniques especially for pig urine as grassland fertilizer.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.5
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• pp.577-583
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• 2007

To overcome certain disadvantages of past typical control techniques for toxic contaminants emitted from various industrial processes, the current study was conducted to establish a thermal catalytic system using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst and to evaluate catalytic thermal destruction of five chlorinated hydrocarbons[chlorobenzene(CHB), chloroform(CHF), perchloroethylene (PCE), 1,1,1-trichloroethane(TCEthane), trichloroethylene(TCE)]. In addition, this study evaluated the catalyst poison effect on the catalytic thermal destruction. Three operating parameters tested for the thermal catalyst system included the inlet concentrations, the incineration temperature, and the residence time in the catalyst system. The thermal decomposition efficiency decreased from the highest value of 100% to the lowest value of almost 0%(CHB) as the input concentration increased, depending upon the type of chlorinated compounds. The destruction efficiencies of the four target compounds, except for TCEthane, increased upto almost 100% as the reaction temperature increased, whereas the destruction efficiency for TCEthane did not significantly vary. For the target compounds except for TCEthane, the catalytic destruction efficiencies increased up to 30% to 97% as the residence time increased from 10 sec to 60 sec, but the increase of destruction efficiency for TCEthane stopped at the residence time of 30 sec, suggesting that long residence times are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Conclusively, the current findings suggest that when applying the transition-metal catalyst for the better destruction of chlorinated hydrocarbons, VOC type should be considered, along with their inlet concentrations, and reaction temperature and residence time in catalytic system. Meanwhile, the addition of high methyl sulfide(1.8 ppm) caused a drop of 0 to 50% in the removal efficiencies of the target compounds, whereas the addition of low methyl sulfide (0.1 ppm), which is lower than the concentrations of sulfur compounds measured in typical industrial emissions, did not cause.

• Elastomers and Composites
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• v.49 no.1
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• pp.53-58
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• 2014

In this study, characteristics of visible-light responsive photocatalyst Weltouch, especially VOCs reduction of visible-light responsive photocatalyst coated nylon/polyester composite fiber for vehicle interior parts and materials were evaluated. Visible-light responsive photocatalyst Weltouch was observed for both anatase phase and rutile phase. It is activated by light longer than 420nm. VOCs and formaldehyde generated from visible-light responsive photocatalyst treated nylon/polyester composite fiber were reduced confirmly. Visible-light responsive photocatalyst was firmly attached to the surface of nylon/polyester composite fiber without elimination even after 25 times repeated washing. And washing durability of nylon/polyester composite fiber confirmed the excellence that reduction effects of VOCs after repeated washing has appeared as much as before washing.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.491-498
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• 2009

We studied to develop high-efficiency removal system of odor and VOCs(Volatile Organic Compounds) from environmental infrastructure facilities and oil refineries, painting facilities and so on. It can replace RTO and RCO. We tried an removal experiment for VOCs (toluene, xylene, benzene, MEK(methyl ethyl ketone), ethanol, formalin etc. and odor compounds (hydrogen sulfide, etc.). In process, as pre-treatment we used the scrubber with vortex flow (Multi-scrone) to remove the hydrophilic VOCs and as post-treatment, used fibrous bio-filter to remove the hydrophobic VOCs. This hybrid system remove with high efficiency both the hydrophilic VOCs and hydrophobic VOCs. And we tried to make this system to be compact. In experiment using Multi-scrone, contact time is 2~3 seconds and absorption scrubbing water is diaphragm-type electrolysis water. hydrophilic VOCs like ethanol and relatively hydrophilic odor compounds like hydrogen sulfide is excellent, these substances has been removed almost completely, respectively 95~99%, 93~97%. And for MEK, formalin also Showed a high removal efficiency, respectively 78~90%, 72~85%. But in experiment using Multi-scrone, the hydrophobic VOCs like BTX showed a low removal efficiency, respectively 16~22%, 12~18%, 8~16%. In hydrophobic VOCs, toluene removal experiment using fibrous bio-filter, early efficiency was low but after 10days, adaptation period showed high efficiency 85~95%. but in the mixed phase, toluene and MEK efficiency reduced 5~10%. this show microorganism treat first MEK easy to remove. The removal efficiency for MEK using the fibrous biofilter was stable, 80~92%. This hybrid system is also high economical efficiency for RTO. This system reduce more than 50% the cost of equipment and maintenance. As a result, we expect this technology is in the limelight as high efficiency treatment of VOCs in mid-low price.

• The Journal of Engineering Geology
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• v.13 no.4
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• pp.389-404
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• 2003

VOCs were detected in the 21 groundwaters out of 37 groundwaters sampled from around the Hanam Industrial Complex and the Gwangju stream. Ten components of chlorinated aliphatic hydrocarbons of VOCs were detected in the 18 groundwater samples. Among them, total trihalomethanes (TTHM) concentration is in the range of $0.1~36.2{\;}\mu\textrm{g}/L$, CECs concentration is $2.3~190{\;}\mu\textrm{g}/L$, and chlorinated solvents concentration containing PCE, TCE, etc. is $0.1~124.2{\;}\mu\textrm{g}/L$ respectively. Ten components of the aromatic hydrocarbons of VOCs were detected in the 5 groundwater samples, but their concentration are less than $1{\;}\mu\textrm{g}/L$. Detection frequency and concentration of the chlorinated aliphatic hydrocarbons components from the groundwaters in the Hanam Industrial Complex are higher than those of nearby downtown Gwangju stream. VOCs components except for TCE are lower than the MCL of USGS drinking water standard. TCE concentration of the 2 groundwater samples is over MCL, whose concentrations are 5 and 25 times higher than MCL, respectively. TCE is detected from the H8 and H10 groundwater samples and CFCs is detected H8 and H11 groundwater samples in the Hanam Industrial Complex. TTHM in study area is estimated from leakage of the main waters or sewage waters. Because most of the studied groundwater is under an aerobic condition, aromatic hydrocarbons are well degraded. But chlorinated aliphatic hydrocarbons are degraded very slowly.

• Clean Technology
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• v.21 no.1
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• pp.76-82
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• 2015

Volatile organic compounds (VOC) free adhesives have been interested by many scientists and engineers due to environmental regulations and the safety of industrial workers. In this work, a series of composites composed with bisphenol A epoxy resin used as solvent, dicyandiamide, and promoter were prepared to investigate the most appropriate molar ratio for steel-steel adhesion. The cured test specimen of each composite were measured with universal testing machine (UTM) to figure out mechanical properties such as tensile strength, Young’s modulus, and elongation. Furthermore, the lap shear strength of the specimen was tested with UTM while impact resistance was measured with Izod impact tester. The composite whose molar ratio of epoxy resin to curing agent is 1 : 0.9 (sample 3), showed better tensile strength, coefficient of elastic modulus, elongation, and impact strength than other composites did. The highest tanδ from dynamic mechanical analysis (DMA) was observed from sample 2 (epoxy resin: dicy = 1 : 0.7) while sample 3 showed slightly lower tanδ than that of 2. The morphology of the fracture surface of the cured composites from SEM showed that the number of subtle lines on the surface caused by impact increase as the contents of amine curing agent accrete. Furthermore, the viscosity change of sample 5 (epoxy resin: dicy = 1 : 1.3) was observed to confirm its storage stability.

• Solar Energy
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• v.12 no.2
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• pp.62-78
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• 1992

The solar cells of $ITO_{(n)}/Si_{(p)}$, which are ITO thin films deposited and heated on Si wafer 190[$^{\circ}C$], were fabricated by two source vaccum deposition method, and their electrical properties were investigated. Its maximum output is obtained when the com- position of the thin film consist of indium oxide 91[mole %] and thin oxide 9[mole %]. The cell characteristics can be improved by annealing but are deteriorated at temperature above 600[$^{\circ}C$] for longer than 15[min]. Also, we investigated the spectral response with short circuit current of the cells and found that the increasing of the annealing caused the peak shifted to the long wavelength region. And by experiment of the X-ray diffraction, it is shown to grow the grains of the thin film with increasment of annealing temperature. The test results from the $ITO_{(n)}/Si_{(p)}$ solar cell are as follows. short circuit current : Isc= 31 $[mW/cm^2]$ open circuit voltage : Voc= 460[mV] fill factor : FF=0.71 conversion efficiency : ${\eta}$=11[%]. under the solar energy illumination of $100[mW/cm^2]$.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1126-1133
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• 2010

A two-stage biofilter was constructed and utilized to determine the removal efficiency when treating dynamic loading of a mixture of odorous compounds including benzene, toluene, p-xylene, ammonia and hydrogen sulfide. A yeast strain, Candida tropicalis, and a sulfur oxidizing bacterial (SOB) strain, Acidithiobacillus caldus sp., were immobilized in polyurethane media and packed in the two-stage biofilter. The experiment of dynamic loading variation was composed of (1) stepwise loading variation of all the odorous compounds (total EC test), (2) stepwise loading variation of each odorous compound, and (3) intermittent loading variation with 2-day-off and 3-day-on. The total EC test showed that the maximum elimination capacity was $61\;g/m^3/hr$ for total VOCs, and 5.2 and $9.1\;g/m^3/hr$ for ammonia and hydrogen, respectively. In addition, the inhibition between VOCs was observed when the loading of each individual VOC was varied. Especially the stepwise increase in toluene loading resulted in decreases of benzene and p-xylene removal efficiencies about 30% and 25%, respectively. However, the inhibition between organic and inorganic compounds was not observed. The intermittent loading variation with 2-day-off and 3-day-on showed that greater than 95% of the overall removal efficiency was restored in two days after the loading resumed. Consequently, the two-stage biofilter packed with immobilized microorganisms showed advantages over conventional biofilters for the simultaneous treatment of the mixture of organic and inorganic odorous compounds.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.187-193
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• 2008

Biological removal capacities for volatile organic compounds (VOCs) were determined using a yeast strain, Candida tropicalis. In this study, VOCs including toluene, benzene, p-xylene, and styrene as single substrates or mixtures were tested in the batch culture of the yeast strain. In addition, a kinetic model was applied to evaluate substrate interactions between the VOCs. The yeast strain was able to biodegrade each VOC effectively as a growth substrate, implying it could applied to wide range of VOCs. When the yeast strain was subjected to VOCs in mixtures, the biodegradation rate of one substrate were either increased (stimulated) or decreased (inhibited) by the presence of the others. Both benzene and toluene were inhibited by the other VOCs, and substrate interaction parameters estimated in the model indicated that styrene was the strongest inhibitor for the benzene and toluene biodegradation. Meanwhile, the biodegradation of p-xylene and styrene was stimulated by the presence of either benzene or toluene. The biodegradation rate of p-xylene was significantly increased especially by the presence of toluene, and the styrene biodegradation was enhanced greatly by the benzene addition. The results of the substrate interaction by the yeast strain suggest that the biodegradation rates for the VOCs in mixtures should be carefully evaluated. Furthermore, the competitive inhibition coefficient could be applied as a useful index to determine the substrate interaction