• Journal of Environmental Health Sciences
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• v.38 no.3
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• pp.213-222
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• 2012

Objectives: This study was undertaken in order to evaluate by work space zoning and structure the concentrations of biological contaminants in the indoor air of domestic office buildings. Methods: Air samples were collected in the office spaces of 15 office buildings in Seoul from June 28 to July 28, 2011. Prior to the sampling, each office was classified into 'open-plan office', 'cellular office' and 'mixed office' according to the work space zoning. To evaluate the biological contamination of indoor air, total suspended bacteria (TSB), Gram positive bacteria (GPB), Staphylococcus aureus (S.A), Methicillin-resistant Staphylococcus aureus (MRSA), Gram negative bacteria (GNB) and fungi were investigated. During the sampling, temperature, relative humidity and carbon dioxide ($CO_2$) were measured. Results: The TSB concentrations ($GM{\pm}GSD$) were $452({\pm}1.3)cfu/m^3$ in open-plan offices, $366({\pm}1.3)cfu/m^3$ in cellular offices and $287({\pm}1.5)cfu/m^3$ in mixed offices, and there were significant differences between the three groups (p<0.05). The highest concentrations ($GM{\pm}GSD$) of fungi were found in the indoor air of cellular offices $128({\pm}1.0)cfu/m^3$, which was at least three times higher than the concentrations in mixed offices $43({\pm}1.0)cfu/m^3$ (p<0.05). Conclusions: Microbiological contamination in the indoor air of office buildings by work space structure was the highest with the open-plan office layout which includes no high walls or doors separating the occupants.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1928-1935
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• 2015

Microbial growth kinetics is often used to optimize environmental processes owing to its relation to the breakdown of substrate (contaminants). However, the quantification of bacterial populations in the environment is difficult owing to the challenges of monitoring a specific bacterial population within a diverse microbial community. Conventional methods are unable to detect and quantify the growth of individual strains separately in the mixed culture reactor. This work describes a novel quantitative PCR (qPCR)-based genomic approach to quantify each species in mixed culture and interpret its growth kinetics in the mixed system. Batch experiments were performed for both single and dual cultures of Pseudomonas putida and Escherichia coli K12 to obtain Monod kinetic parameters (μ_max and K_s). The growth curves and kinetics obtained by conventional methods (i.e., dry weight measurement and absorbance reading) were compared with that obtained by qPCR assay. We anticipate that the adoption of this qPCR-based genomic assay can contribute significantly to traditional microbial kinetics, modeling practice, and the operation of bioreactors, where handling of complex mixed cultures is required.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.95-98
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• 1999

The goal of present study is to evaluate the potential of soil washing for removing metal contaminants from a contaminated soil. Remediation of a soil contaminated with copper, cadmium and phenol were performed by a soil washing using a biosurfactant. The removal of copper, cadmium and phenol from soil (sandy, kaoline, mixed one) was evaluated as a function of biosurfactant (wt %) concentration in the batch process. The results showed that overall rejection coefficient for copper, cadmium and phenol were grater than 50 %, 25 %, respectively.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.204-211
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• 2016

Oil pollution seriously endangers the biological environment and human health. Due to the diversity of oils and the complexity of oil composition, it is of great significance to identify the oil contaminants. The 3-D fluorescence spectrum combined with a second order correction algorithm was adopted to measure an oil mixture with overlapped fluorescence spectra. The self-weighted alternating trilinear decomposition (SWATLD) is a kind of second order correction, which has developed rapidly in recent years. Micellar solutions of #0 diesel, #93 gasoline and ordinary kerosene in different concentrations were made up. The 3-D fluorescence spectra of the mixed oil solutions were measured by a FLS920 fluorescence spectrometer. The SWATLD algorithm was applied to decompose the spectrum data. The predict concentration and recovery rate obtained by the experiment show that the SWATLD algorithm has advantages of insensitivity to component number and high resolution for mixed oils.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.168-171
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• 2003

This research was conducted to assess the performance of the mixed reactive materials with sand, iron filings, and HDTMA-bentonite for trichloroethylene (TCE) and chromate removal under controlled groundwater flow conditions. TCE and chromate removal rates with the mixtures of iron filing/HDTMA-bentonite were highest among four columns due to reduction by iron filings and sorption by HDTMA-bentonite. The greater capacity of the mixed iron filing/HDTMA-bentonite compared HDTMA-bentonite was due to an enhanced chromate reduction in addition to chromate sorption. The presence of chromate caused greater inhibition of TCE removal in the column with iron filings, while the presence of TCE caused less inhibition of TCE. Also, nitrate caused the decrease in TCE removal relative to chloride. Nitrate ions may also significantly affect TCE reduction rates by competing for electrons with the chlorinated compounds. The anion and co-existed contaminants competing effects should be considered when designed permeable reactive barriers (PRBs) composed of zero valent iron for field applications to remediate TCE and chromate.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.82-88
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• 2017

Contaminated sediment can be treated in order to reuse the treated sediment. Even though the chemical criteria are satisfied, the treated sediment could still impose toxic effects. Therefore, this study investigated the changes in the ecological toxic effects of the contaminated sediment from the J region in Singapore after treatment. The contaminated sediment was subject to sequential soil washing and thermal treatment, followed by pH neutralization. Toxic effects of the contaminated and treated sediments were determined by using Vibrio fischeri ($Microtox^{(R)}$), Triticum aestivum (wheat), and Eisenia foetida (earthworm). After treatment, the concentrations of total petroleum hydrocarbons and heavy metals were decreased by 98% and 59-93%, respectively, and satisfied the Industrial Maximum Values of the Dutch Standard, which were used as the remedial goal. The bioluminescence reduction of V. fischeri decreased significantly, and the earthworm survival increased from 0% to 90% after treatment. The germination rate increased from $0{\pm}0%$ to $75{\pm}13%$ after treatment, but the treated sediment may need additional treatment such as nutrient addition for better plant growth. Overall, this study showed that the treatment of the contaminated sediment satisfactorily removed mixed contaminants, and this led to reduction in toxic effects, suggesting improved potentials for reuse of the treated sediment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.293-300
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• 2005

Ultrasonic decontamination of the type 304 stainless steel specimen loosely contaminated with $Eu_2O_3$ powders was investigated. Decontamination factors (DFs) by the three kinds of ultrasonic media such as water, pure PFC (Pefluorocarbon, $C_7F_{16}$) and a mixed solution of $99.9\;vol\%\;PFC\;and\;0.1\;vol\%$ anionic surfactant were determined. The determined DF values were 20, 50 and 200, respectively. This significant difference in the decontamination factors for the different decontamination solution was well explained by the surface tension of the media as well as the interaction between the positively charged surface of $Eu_2O_3$ powders and the anionic surfactant. Ultrasonic decontamination behavior of the loosely contaminated metal specimens such as plate, pipe, welding specimen and crevice specimen in the mixed solution of PFC and anionic surfactant was also investigated. The contaminants were completely removed for the tested specimens except for the longest specimen. For 6-cm long pipe specimen, however, $98.5\%$ of the contaminants were removed.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.593-596
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• 2006

The environment-friendly building material, photocatalyst/scoria/loess concrete, was prepared using scoria and loess (which have merits as building materials) and photocatalyst (which has the functions to compose the environmental contaminants and of self cleaning). In order to apply this material as a building material, the compressive and flexible strengths, and water absorptivity (which have been set by Korea Industrial Standard) were measured. In order to know the environment-friendly characteristics of this material, several tests, such as, the tests of emissivity and emission power of far infrared ray and acoustic absorptivity, antibacterial test for Escherichia coli and Pseudomonas aeruginosa, antifungal test for mixed fungal strains, and deodorization test of ammonia were carried out. Moreover, the removal characteristics of NOx, and formaldehyde (HCHO) by photocatalyst/scoria/loess concrete were examined as the following different parameters: the removal characteristics of these contaminants with the substitution ratio and the kind of photocatalyst, light source, UV intensity of sunlight, relative humidity, intial NOx concentration.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.89-94
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• 2020

BACKGROUND: Persistent organic contaminants such as dichlorodiphenyltrichloroethane (DDT) are often found in agricultural soils decades after it was banned in Korea. This study uses hemoglobin and hemoglobin-containing blood meal to reduce the residual DDT in soil. METHODS AND RESULTS: Hemoglobin or blood meal with or without hydrogen peroxide (H₂O₂) was mixed with the DDT-spiked soil prepared for this study, and samples were taken over 14 d-degradation period to measure the residual DDT concentrations. With only hemoglobin, DDT was completely removed after 14 d, while with both hemoglobin and H₂O₂, 73%, on average, removal was observed. Similarly, the blood meal removed 73% of DDT, but with H₂O₂, the DDT removal was only 39%. The lower DDT removal in the presence of H₂O₂ can be attributed to the adverse effects of reactive species. Hemoglobin was more effective than blood meal for DDT removal in a given time; however, with additional blood meal injection, complete DDT removal was achieved. CONCLUSION: Overall, this study shows that the blood meal that is used as a fertilizer can potentially be used to remove residual contaminants such as DDT in agricultural soil.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.30-36
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• 2004

Waste papers(MOW and ONP) were deinked with alkaline cellulolytic enzyme from Coprinus cinereus 2249. The effectiveness of alkaline enzyme on sticky contaminant removal and bleaching of recycling pulp was investigated. The conclusions obtained from the results are as follows. The brightness of deinked pulps MOW and ONP was most high in 0.4IU enzyme treatment. \circled2 The removal effect of sticky contaminant was enhanced with alkaline cellulolytic enzyme treatment. Bleaching with sodium hydrosulfite was most effective in one and two stage bleaching after enzyme treatment of mixed wastepaper of MOW and colored paper. \circled4 The brightness of alkaline enzyme deinked ONP was increased 20％ with $H_2O$$_2$ bleaching.