• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.901-908
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• 2002

The relationship between the layered structure of granules in UASB reactors and microbial resistance to toxicity was investigated using disintegrated granules. When no toxic materials were added to the media, the intact and disintegrated granules exhibited almost the same ability to decrease COD and to produce methane. However, when metal ions and organic toxic chemicals were added to a synthetic wastewater, he intact granules were found to be more resistant to toxicity than the disintegrated granules, as determined by the methane production. The difference in resistance between the intact and disintegrated granules was maximal, with toxicant concentrations ranging from 0.5 mM to 2 mM for trichloroethylene with toluene and 5 mM to 20 mM for metal ions (copper, nickel, zinc. chromium, and cadmium ions). The augmented COD removal rate by granulation compared to disintegrated granules was also measured in the treatment of synthetic and real wastewaters; synthetic wastewater, $-2.6\%$; municipal wastewater, $2.8\%$; swine wastewater, $6.4\%$; food wastewater, $25.0\%$; dye works wastewater, $42.9\%$; and landfill leachate, $61.8\%$. Continuous reactor operation also demonstrated that the granules in the UASB reactor were helpful in treating toxic wastewater, such as landfill leachate.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.625-630
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• 2010

This study aims to examine the possible use of heavy oil fly ash as raw material for deodorization panels by adding additives such as activated carbon and diatomite during deodorization panel manufacturing process and improving the performance of formaldehyde and toluene elimination.The recycled heavy oil flyash deodorization panel to be used either of them as additives removed more than 93% of formaldehyde and more than 97% of toluen but the compressive strength was decreased 27 to 63%. In an experiment to be used both additives, Whereas, the panel to include activated carbon 5% and diatomite 5% removed 84% against formaldehyde and 96% against toluen, and the compressive strength was increased 32% better than standard panel. Therefore it could be confirmed that the recycled heavy oil flyash deodorization panel is increased the compressive strength and the removal efficiency against harmful chemical substances by using the additives mixture.

• Environmental Engineering Research
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• v.14 no.4
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• pp.212-219
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• 2009

Emission characteristics of air pollutants from three commercially operating cement kilns co-burning waste were investigated. The major heavy metals emitted were mercury (Hg), zinc (Zn), nickel (Ni), chromium (Cr), lead (Pb), cadmium (Cd), and arsenic (As) Removal efficiency of the bag filter was above 98.5% for heavy metals (except Hg), and above 60% for Hg. Higher fractions of heavy metals entering the bag filter were speciated to cement kiln dust. On average, 3.3% of the -heavy metals of medium and low toxicity (Pb, Ni, and Cr) entering the bag filter were released into the atmosphere. Among highly toxic heavy metals, 0.14% of Cd, 0.01% of As, and 40% of Hg entering the bag filter were released into the atmosphere. In passing through the bag filter, the proportion of oxidized Hg in all cases increased. Emission variations of hazardous air pollutants in cement kilns tested were related to raw materials, fuel, waste feed and operating conditions. Volatile organic compounds detected in gas emissions were toluene, acrylonitrile benzene, styrene, 1,3-butadiene, and methylene chloride. Although hazardous air pollutants in emissions from cement kilns co-burning waste were within the existing emission limit, efforts are required to minimize their levels.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.535-539
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• 2008

Conversion to oil, yield of styrene and formation of side products such as ${\alpha}-methyl$ styrene, ethyl benzene, benzene, toluene, dimer and trimer were affected by residue formed during thermal degradation. Also, control of reaction temperature had a difficulty at the first stage. Thus, new reaction system using wetted-wall type reactor was proposed and examined on various parameters such as reaction temperature, feeding rate and removal velocity of formed vapor. Optimun condition was obtained from continuous thermal degradation using wetted-wall type reactor and reaction kinetic study was carried out at new type reactor.

• KSBB Journal
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• v.24 no.1
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• pp.17-24
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• 2009

For the biosurfactant production process at first Candida bombicola, Sphingomonas yanoikuyae, Sphingomonas chungbukensis and Myxococcus flavescens were studied. As the most productive microorganisms C. bombicola, S. yanoikuyae and S. chungbukensis were selected. During many petrochemical industrial processes variable volatile organic componds are produced and they can cause an unpleasent and unhealthy atmosphere. Usually the volatile organic compounds are treated with chemical detergents. The chemical detergents cannot be easily degradable and can be accumulated in the nature. In this study we tried to develop a production process for the biosurfactants, which can substitute some chemical detergents in some chemical processes, with microorganisms. At second the treatment of the volatile organic compounds with the biosurfactants were tested and compared with the treatment with chemical detergent. The production productivities of the biosurfactant with microorganisms were compared. The growth patterns and kinetics of the microbial cells and the surface tension values of the biosurfactants were studied. The changes of the surface tension in variable pH conditions and sodium chloride concentrations were also studied. The volatile organic carbons were treated in a small plant scale. As the result of this study, it indicated that the specific growth rate of S. chungbukensis was the fastest by 0.144 ($hr^{-1}$). For surface tension, C. bombicola (38.1 dyne/cm) had the lowest value, and solubility of the volatile organic carbon was similar in C. bombicola and S. chungbukensis. (Toluene: about 0.1 Unit, Chloroform: about 0.6${\sim}$0.7 Unit, Benzene: about 0.5${\sim}$0.8 Unit). The biosurfactant, which were produced by C. bombicola, was selected for the further study for the volatile organic carbon treatment. With the biosurfactans from C. bombicola could remove the volatile organic carbon about 80% and this removal rate can be comparable with chemical detergent.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.211-215
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• 2014

The Pt-, Ni- and Cr-decorated tubular $SnO_2$ nanofibers for gas sensors were prepared by the electrospinning of polyvinylpyrrolidone (PVP) nanofibers containing Pt, Ni, and Cr precursors, the sputtering of $SnO_2$ on the electrospun PVP nanofibers, and the removal of sacrificial PVP parts by heat treatment at $600^{\circ}C$ for 2 h. Pt-decorated tubular $SnO_2$ nanofibers showed high response ($R_a/R_g=210.5$, $R_g$: resistance in gas, $R_a$: resistance in air) to 5 ppm $C_2H_5OH$ at $350^{\circ}C$ with negligible cross-responses to other interference gases (5 ppm trimethylamine, $NH_3$, HCHO, p-xylene, toluene and benzene). Cr-decorated tubular $SnO_2$nanofibers showed the selective detection of p-xylene at $400^{\circ}C$. In contrast, no significant selectivity to a specific gas was found in Ni-decorated tubular $SnO_2$ nanofibers. The selective and sensitive detection of gases using Pt-decorated and Cr-decorated tubular $SnO_2$ nanofibers were discussed in relation to the catalytic promotion of gas sensing reaction.

• Safety and Health at Work
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• v.15 no.2
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• pp.228-235
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• 2024

Background: Glove reuse poses risks, as chemicals can persist even after cleaning. Decontamination methods like thermal aeration, recommended by US OSHA, vary in effectiveness. Some studies show promising results, while others emphasize the importance of considering both permeation and tensile strength changes. This research advocates for informed glove reuse, emphasizing optimal thermal aeration temperatures and providing evidence to guide users in maintaining protection efficiency. Methods: The investigation evaluated Neoprene and Nitrile gloves (22 mils). Permeation tests with toluene and acetone adhered to American Society for Testing Materials (ASTM) F739 standards. Decontamination optimization involved aeration at various temperatures. The experiment proceeded with a maximum of 22 re-exposure cycles. Tensile strength and elongation were assessed following ASTM D 412 protocols. Breakthrough time differences were statistically analyzed using t-test and ANOVA. Results: At room temperature, glove residuals decreased, and standardized breakthrough time (SBT)₂ was significantly lower than SBT₁, indicating reduced protection. Higher temperature decontamination accelerated residual removal, with ∆SBT (SBT₂/SBT₁) exceeding 100%, signifying restored protection. Tensile tests showed stable neoprene properties postdecontamination. Results underscore thermal aeration's efficacy for gloves reuse, emphasizing temperature's pivotal role. Findings recommend meticulous management strategies, especially post-breakthrough, to uphold glove-protective performance. Conclusions: Thermal aeration at 100℃ for 1 hour proves effective, restoring protection without compromising glove strength. The study, covering twenty cycles, suggests safe glove reuse with proper decontamination, reducing costs significantly. However, limitations in chemical-glove combinations and exclusive focus on specific gloves caution against broad generalization. The absence of regulatory directives on glove reuse highlight the importance of informed selection and rigorous decontamination validation for workplace safety practices.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.85-95
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• 2018

In this research, a biofilter system equipped with a biofilter process and a humidifier composed of a fluidized aerobic and an anoxic reactor, was constructed to treat odorous waste air containing hydrogen sulfide, ammonia and VOC, frequently generated from pig and poultry housing facilities, compost manufacturing factories and publicly owned facilities. Its optimum operating condition was revealed and discussed. In the experiment of complex feed, the ammonia of fed-waste air was removed by ca. 75% and more than 20% at the stage of the humidifier and the biofilter, respectively. The toluene of the fed-waste air was removed by ca. 20% and more than 70% at the stage of the humidifier and the biofilter, respectively. Therefore the water-soluble ammonia and the water-insoluble toluene were treated mainly at the stage of the humidifier and the biofilter, respectively. In addition, hydrogen sulfide was almost absorbed at the stage of the humidifier so that it was not detected at the biofilter process. In the experiment of ammonia-containing feed, the ammonia of fed-waste air was removed by ca. 65% and 35% at the stage of the humidifier and the biofilter, respectively. Its removal efficiency of ammonia at the stage of the humidifier was 10% less than that in the experiment of complex feed, due to no supply of such carbon source as toluene required in the process of denitrification. In the experiments of complex feed, ammonia-containing feed with and without (instead, glucose) the addition of yeast extract, the absorption rates of ammonia-nitrogen were ca. 0.28 mg/min, 0.23 mg/min and 0.27 mg/min, respectively. The corresponding denitrification rates in the anoxic reactor were 0.42 mg/min, 0.55 mg/min and 0.27 mg/min, respectively. In addition, in the modeling of bubble column(the fluidized aerobic reactor of the humidifier) process, the value of specific surface area(a) of bubbles multiplied by enhanced mass transfer coefficient (E $K_y$) was evaluated to be 0.12/hr.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.35-43
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• 2005

Bioslurping combines the three remedial approaches of bioventing, vacuum-enhanced free-product recovery, and soil vapor extraction. Bioslurping is less effective in tight (low-permeability) soils. The greatest limitation to air permeability is excessive soil moisture. Optimum soil moisture is very soil-specific. Too much moisture can reduce air permeability of the soil and decrease its oxygen transfer capability. Too little moisture will inhibit microbial activity. So Modified Fenton reaction as chemical treatment which can overcome the weakness of Bioslurping was experimented for simultaneous treatment. Although the diesel removal efficiency of SVE process increased in proportion to applied vacuum pressure, SVE process was difficulty to remediation quickly semi- or non-volatile compounds absorbed soil strongly. And SVE process had variation of efficiency with distance from the extraction well and depth a air flow form of hemisphere centering around the well. Below 0.1 % hydrogen peroxide shows the potential of using hydrogen peroxide as oxygen source but the co-oxidation of chemical and biological treatment was impossible because of the low efficiency of Modified Fenton reaction at 0.1 % (wt) hydrogen peroxide. NTA was more efficiency than EDTA as chelating agent and diesel removal efficiency of Modified Fenton reaction increased in proportion to hydrogen peroxide concentration. Hexadecane as typical aliphatic compound was removed less than Toluene as aromatic compound because of its structural stability in Modified Fenton reaction. What minimum 10% hydrogen peroxide concentration has good remediation efficiency of diesel contaminated groundwater may show the potential use of Modified Fenton reaction after bioslurping treatment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.431-439
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• 2006

A lot of particulate matter and an offensive odor are emitted during the operations of an industrial waste incinerator (IWI), especially pre_treatment and waste input processes. These pollutants affect the labor efficiency of an operator. Therefore, in this study. we have studied the improvement of working surroundings in the industrial waste incinerator by designing a new control system. A computational fluid dynamics has been used to find the diffusion flows of air pollutants (mainly particles and odor) to the working surroundings of the waste treatment complexes. The results obtained from the simulation analysis applied to the basic design on the points (and/or site) and types of pollution control devices. When pollutant control devices are constructed, the concentration of each pollutant at site 1 and 2 decreased about 83-97% for toluene, 48-72% for styrene, 75-87% for xylene, and 23-36% for ammonia, respectively. In addition, the PM-10 and TSP were decreased about 87% and 86% at site 3 (lower part of the waste input), 87% and 85% at site 4 (side part of the waste input), respectively. These indicated that the new control system had an excellent performance of particulate matter and odor removal and it could be applied to other waste treatment plant in place of an industrial waste incinerator.