• Membrane and Water Treatment
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• v.13 no.4
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• pp.183-189
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• 2022

This study seeks towards an optimal way to control sulfate ions in semiconductor wastewater effluent with potential eco-toxicity. We developed a system based on ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O). The basic idea is that the pH of the water is raised to approximately 12 with Ca(OH)₂. After, aluminium salt is added, leading to the precipitation of ettringite. Lab-scale batch and continuous experiment results with real semiconductor wastewater demonstrated that 1.5 and 1 of stoichiometric quantities for Ca²⁺ and A³⁺ with pH above 12.7 could be considered as the optimal operation condition with 15% of sludge recycle to the influent. A mixed AlCl₃ + Fe reagent was selected as the beneficial Al³⁺ source in ettringite process, which resulted in 80% of sludge volume reduction and improved sludge dewaterability. The results of continuous experiment showed that with precipitation as ettringite, sulfate concentration can be stably reduced to less than 50 mg/L in effluent from the influent 2,050 ± 175 mg/L on average (1,705 ~ 2,633 mg/L).

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.3
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• pp.329-341
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• 2005

The purpose of this study is to study the $PM_{2.5}$ source characteristics affecting the Seoul area using a chemical mass balance (CMB) receptor model. This study was also to evaluate the $PM_{2.5}$ source profiles, which were directly measured and developed. Asian Dust Storm usually occurred in the spring, and very high $PM_{2.5}$ concentrations were observed in the fall among the sampling periods. So the ambient data collected in the spring and fall were evaluated. The CMB model results as well as the $PM_{2.5}$ source profiles were validated using the diagnostic categories, such as: source contribution estimate, t-statistic, R-square, Chi-square, and percent of total mass explained. In the spring months, the magnitude of $PM_{2.5}$ mass contributors was in the following order: Chinese aerosol $(31.7\%)>$ secondary aerosols ($22.3\%$: ammonium sulfate $13.4\%$ and ammonium nitrate $8.9\%)>$ vehicles ($16.1\%$: gasoline vehicle $1.4\%$ and diesel vehicles $14.7\%)>$biomass burning $(15.5\%)>$ geological material $(10.5\%)$. In the fall months, the general trend of the $PM_{2.5}$ mass contributors was the following: biomass burning $(31.1\%)>$ vehicles ($26.9\%$: gasoline vehicle $5.1\%$ and diesel vehicles $21.8\%)>$ secondary aerosols ($23.0\%$: ammonium sulfate $9.1\%$ and ammonium nitrate $13.9\%)>$ Chinese aerosol $(10.7\%)$. The results show that the $PM_{2.5}$ mass in the Seoul area was mainly affected by the Chinese area.

• Economic and Environmental Geology
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• v.42 no.5
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• pp.445-455
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• 2009

Microbiological sulfate reduction is the transformation of sulfate to sulfide catalyzed by the activity of sulfate-reducing bacteria using sulfate as an electron acceptor. Low solubility of metal sulfides leads to precipitation of the sulfides in solution. The effects of microbiological sulfate reduction on in-situ precipitation of arsenic and copper were investigated for the heavy metal-contaminated soil around the Songcheon Au-Ag mine site. Total concentrations of As, Cu, and Pb were 1,311 mg/kg, 146 mg/kg, and 294 mg/kg, respectively, after aqua regia digestion. In batch-type experiments, indigenous sulfate-reducing bacteria rapidly decreased sulfate concentration and redox potential and led to substantial removal of dissolved As and Cu from solution. Optimal concentrations of carbon source and sulfate for effective microbial sulfate reduction were 0.2~0.5% (w/v) and 100~200 mg/L, respectively. More than 98% of injected As and Cu were removed in the effluents from both microbial and chemical columns designed for metal sulfides to be precipitated. However, after the injection of oxygen-rich solution, the microbial column showed the enhanced long-term stability of in-situ precipitated metals when compared with the chemical column which showed immediate increase in dissolved As and Cu due to oxidative dissolution of the sulfides. Black precipitates formed in the microbial column during the experiments and were identified as iron sulfide and copper sulfide. Arsenic was observed to be adsorbed on surface of iron sulfide precipitate.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.508-519
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• 2015

The objective of this study was to quantitatively estimate $PM_{2.5}$ source contribution in Gyeongsan. Ambient $PM_{2.5}$ samples have been collected on zefluor, quartz and nylasorb filter by $PM_{2.5}$ samplers of cyclone method from September 2010 to December 2012. Collected samples were analyzed for determining 17 inorganic elements, 8 ions, and 8 carbon components after pretreatment. Based on these chemical information, the PMF model was applied to estimate the quantitative contribution of air pollution sources. The results of the PMF modeling showed that the sources were apportioned by biomass burning source (15.5%), secondary sulfate source (16.0%), industry source (10.4%), soil source (7.0%), gasoline source (9.1%), incinerator source (10.4%), diesel emission source (11.0%), and secondary nitrate source (20.6%), respectively. To analyze local source impacts from various wind directions, the CPF analysis were performed using source contribution results with the wind direction values measured at the site.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.436-441
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• 2009

The experiment was conducted to investigate the effect of nitrogen and potassium sources on growth and yield of strawberry 'Seolhyang' and 'Maehyang' in fertigation culture. The plant fresh and dry weight were higher in urea + potassium sulfate and ammonium sulfate + potassium sulfate as nitrogen and potassium sources than others in both varieties. But there were no significant difference among nitrogen and potassium sources in other growth characteristics, such as plant height, no. of leaf, crown diameter etc. Also, the marketable yield of fruit were higher in urea + potassium sulfate and ammonium sulfate + potassium sulfate in 'Seolhyang' than other treatments. 'Maehyang' was better in both treatments but there was no significant difference. The fruit qualities, such as total soluble solid, hardness, acidity, vitamin C content were not significant difference among the treatments. The acidity of soil was tended to decrease but EC was tended to increase highly in ammonium sulfate treatments as a nitrogen source. As above results, the urea and potassium sulfate were recommended as nitrogen and potassium sources for the fertigation culture of strawberry 'Seolhyang' and 'Maehyang'.

• Microbiology and Biotechnology Letters
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• v.5 no.4
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• pp.177-184
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• 1977

Arylsulfatase catalyzes the release of SO$\sub$4//sup2/- from sulfate esters of simple phenols. Arylsolfatase occurs widely in animal tissues and in microorganisms including soil bacteria. Its widespread distribution suggests that it has a rather fundamental function and environmental meaning. It has been shown previously that arylsulfatase of Klebsiella was purified and characterized. A condition of arylsulfatase synthesis was tested with several strains of Serratia. Serratia marcescens could not utilize some sugars, such as xylose, rhamnose, glucosamine and arabinose hut glucose and mannitol as a sole carbon source. However, arylsulfatase synthesis was repressed by glucose but not by mannitol. The enzyme synthesis was repressed ob inorganic sulfate and methionine, and this repression was relieved by addition of tyramine. Arylsulfatase of S. marcescen was purified by fractionation with ammonium sulfate and followed by chromatographies on DEAE-Cellulose CM-Cellulose, and DEAE-Sephadex A-25. The molecular weight of arylsulfatase was determined to be 46,000 by SDS-Gel electrophoresis and 49,000 by Sephadex G-100 column chromatography. The enzyme showed some different properties with that of K. aerogenes. The activity was maximum at pH 6.8. The Km and Vmax values for p-nitrophenyl sulfate were 2.5${\times}$10$\^$－4/ M and 20 nmoles/min/mg protein, respectively. The enzyme showed high activities toward phenyl sulfate, ο-and p-nitro phenyl sulfates, and p-nitrocatechol sulfate. The inhibition of enzyme was strongly affected by hydroxylamine, inorganic fluoride, sulfide and phosphate, but by inorganic sulfate. Like Klebsiella arylsulfatase, tyramine, octopamine, and dopamine gave signifcant inhibitory effect.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.58-68
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• 1999

This experiment was to investigate decoloization characteristics of E1 effluents from the bleaching plant of pulp mill with three white-rot fungi(Trametes versicolor, Ganoderma appanatum and Pleurotus ostreatus).In addition, the effect of carbon and nitrogen resources was discussed on its decolorization. The color removal of E1 effluent during shaking and stationary cultures were 72% and 80%, respectively. Stationary culture was more effective on decolorization of E1 effluent compared to the shaking culture. The optimum inoculum weight was 1.0g based on dry weight of mycelia . The decolorization medium I showed 88% of the color removal of E1 effluent with in one day cultivation of T.versicolor and P.ostreatus . Color removal was increased from 87% to 90%. T.versicolor and P.ostreatus by the addition of 0.5% glucose. By addition of nitorgen sources(ammonium sulfate and ammonium choride), medium was much higher than that of carbon source. With 0.1% ammoniumm sulfate, P.ostreatus and T.versicolor showed 94% and 92% of the color removal within one day of cultivation , respectively. On decolorization medium II, T.versicolor and P.ostretus were 94% of oclor removal with addition of carbon source. The addition of nitrogen source was much more efficient than that of carbon source. With 0.1% amminium chloride, T.versicolor and P.ostreatus showed 95% of its color removal . The decolorization medium II was higher color removal than medium I, and also MnP and laccase were produced. However, the decolorization medium I produced a little MnP and laccase activity. It could be suggested that MnP and laccase may play an important role in decolorization of E1 effluent.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.326-336
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• 2016

Saccharomyces cerevisiae is one of the most employed cell factories for the production of bioproducts. Although monomeric hexose sugars constitute the preferential carbon source, this yeast can grow on a wide variety of nitrogen sources that are catabolized through central nitrogen metabolism (CNM). To evaluate the effects of internal perturbations on nitrogen utilization, we characterized strains deleted or overexpressed in GLT1, encoding for one of the key enzymes of the CNM node, the glutamate synthase. These strains, together with the parental strain as control, have been cultivated in minimal medium formulated with ammonium sulfate, glutamate, or glutamine as nitrogen source. Growth kinetics, together with the determination of protein content, viability, and reactive oxygen species (ROS) accumulation at the single cell level, revealed that GLT1 modulations do not significantly influence the cellular physiology, whereas the nitrogen source does. As important exceptions, GLT1 deletion negatively affected the scavenging activity of glutamate against ROS accumulation, when cells were treated with H₂O₂, whereas Glt1p overproduction led to lower viability in glutamine medium. Overall, this confirms the robustness of the CNM node against internal perturbations, but, at the same time, highlights its plasticity in respect to the environment. Considering that side-stream protein-rich waste materials are emerging as substrates to be used in an integrated biorefinery, these results underline the importance of preliminarily evaluating the best nitrogen source not only for media formulation, but also for the overall economics of the process.

• Journal of Radiation Protection and Research
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• v.10 no.1
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• pp.67-73
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• 1985

The manganous sulfate bath method for neutron source calibrations at the K-SRI is described together with the measurement of neutron emission rate of a source and the corrections applied for capture by competing nuclei of neutrons, and thermal neutron leakage, neutron absorption in the source itself. The commercially available neutron sources (Am-Be, $^{252}Cf$) for the calibration checks of neutron radiation instruments in the MeV range are considered in this paper.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.394-397
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• 2000

Lab-scale biofilter was evaluated for the removal of styrene from a waste gas stream. Compost and polyurethane form were used as packing material (50 : 50) and activated sludge from a wastewater treatment plant was innoculated initially. Nitrogen limitation was observed during the biofilter operation and nitrogen source should be properly supplemented. When ammonium sulfate is used as N-source. 200mg carbon was removed for each mg of nitrogen. The effects of the volumetric styrene loading on the styrene elimination capacity (EC) and the removal efficiency (RE) was also tested. The results showed $EC_{max}$ was 4.8kg $C/m^3{\cdot}day$ and above RE 95% was achieved at EBRT 1min.