• The Korean Journal of Food And Nutrition
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• v.29 no.2
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• pp.237-245
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• 2016

In this study, the physicochemical and sensory characteristics of low-salt Myungran jeotkal (Alaskan pollock roe) were evaluated after fermentation at $4^{\circ}C$ and $20^{\circ}C$ with or without the addition of deep sea water, salt from deep sea water, and vegetable-origin lactic acid bacteria (Lactobacillus fermentum JS, LBF). When fermented at $20^{\circ}C$, the addition of LBF to Myungran jeotkal resulted in a slow increase in lactic acid content, followed by an abrupt increase after five days of fermentation. However, when fermented at $4^{\circ}C$, the lactic acid content did not change significantly. Further, when Myungran jeotkal fermented at $4^{\circ}C$, the pH decreased as lactic acid production increased. The salinity of Myungran jeotkal fermented at $4^{\circ}C$ and $20^{\circ}C$ was 7% and was not affected by fermentation period. When fermented at $20^{\circ}C$, volatile basic nitrogen and amino nitrogen contents increased with increasing duration of fermentation. Further, volatile acid content decreased, however, the content of amino nitrogen increased after 11 days of fermentation with LBF and no salt effects were observed. When fermented at $20^{\circ}C$ for 13 days, preference (sensory evaluation) was the highest in all experimental groups after 9 days of fermentation, and then decreased as the fermentation period increased. The free amino acid content was highest (1,648.8 mg/100 g) in Myungran jeotkal when sun-dried salt and LBF were added, 2.3 times higher than in the control.

• Journal of Korean Society on Water Environment
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• v.36 no.4
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• pp.275-283
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• 2020

Fecal coliforms are indicator bacteria to evaluate fecal contamination and microbiological safety in environment water. To examine fecal coliforms by membrane filtration, 1% rosolic acid solution dissolved in sodium hydroxide(0.2 M) should be added to m-FC medium according to Korean standard method. To reduce the exposure of researchers to harmful chemicals and expenditure of unnecessary cost, we evaluated if the rosolic acid solution is required to detect fecal coliforms. For 113 samples collected from five intake sources of Seoul, 42 samples of six tributaries, and 11 samples of sewage, the number of fecal coliforms was compared in medium with or without the reagent. As a result, the number was higher in m-FC medium without the reagent, but there was not a statistically significant difference. In the water intake, m-FC medium without the reagent could be used to examine fecal coliforms except in July, August and in case of rainfall. When heterotrophic plate counts exceeded 1,000 CFU/filter, or during rainfall, there was an effect of background bacteria in two types of the medium. However, it was more appropriate to use m-FC medium with the reagent to suppress gram-positive bacteria that can grow on medium without the reagent. In the tributary and sewage samples, the effect of the background bacteria was low, allowing the use of medium without the reagent regardless rainfall. Thus, it is necessary to present in standard method that the addition of rosolic acid solution in m-FC medium can be selected according to the characteristics of samples.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.141-146
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• 2011

Loess, a natural clay, was evaluated as an adsorbent for the decolorization of Acid Orange II, an azo and reactive dye, from aqueous solution. Adsorption studies were performed at $30^{\circ}C$ and the effect of reaction time, loess dosage, initial concentration, loess particle size, pH, agitation rate were investigated to determine the optimum operation conditions. The removal efficiencies of color were measured to evaluate the effectiveness of loess. From this study, it was found that optimal reaction time was 10 min. Color removal efficiencies of Acid Orange II were increased as higher loess dosage, initial concentration and agitation rate. However, color removal efficiencies decreased when pH is high and loess particle becomes large. Adsorption of Acid Orange II fitted to the pseudo-second-order rate kinetics more than first-order rate kinetics. Langmuir and Freundlich adsorption isotherm constants and correlation coefficients were calculated and compared. It was concluded that the adsorption data of Acid Orange II onto loess fitted to the Freundlich model more than Langmuir model.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.182-186
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• 2001

An acid forest surface soil as a land farming medium was treated with a water plant alum sludge at 0 to 18%. Indian mustard was grown in the treated soil in a greenhouse for 5 weeks and watered with pH 4 tap water adjusted with a mixed acid (1HNO$_3$: 2H$_2$SO$_4$) during plant growth. Changes in soil property, leachate chemistry, plant growth, and plant uptake of elements by the sludge treatment were determined. The alum sludge treatment increased buffer capacity to acidity, hydraulic conductivity, water holding capacity, and phosphate adsorption of the soil and decreased bulk density and mobility of small particles. The sludge treatment reduced leaching of Al, Mg, K, Na, and root elongation. Plant did uptake less amount of the cations and P but more Ca with the sludge treatment.

• The Korean Journal of Ceramics
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• v.5 no.3
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• pp.278-283
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• 1999

Formaldehyde has widely been used for the cross-linking of polyvinyl alcohol polyvinyl alcohol polymer. The effects of formaldehyde on the water resistance of MDF cement composites were investigated as a function of types of catalyst, base or acid, and the amount of formaldehyde. The acetalization, reaction of OH group of PVA with aldehyde, was ended incompletely under base atmosphere. However, by addition of citric acid, the cross-linking of PVA polymer could be acheved through acetalization of PVA and formaldehyde. The effects of these different patterne according to the types of catalyst on the water resistance of MDF cement were studied by the preparation of PVA films and MDF composites. Thanks to the cross-linking reaction of PVA polymer chains by formaldehyde, the modified PVA films and MDF composites showed a good water-resistant propety. The modified MDF cement composite to which 3 wt% formaldehyde and 1 wt% cirtic acid were added showed 80% of initial flexural strength and good interfacial state between cement grain and polymer matrix. However, 4 wt% formaldehyde deteriorted the processing conditions, microstructures and eventually the flexural strength, causing sharp increase in the viscosity of sample dough during the mixing process. To study the relatins of flexural strength and interface of cement grain and polymer matrix, SEM and MIP measurement were performed.

• Korean Journal of Clinical Laboratory Science
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• v.40 no.1
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• pp.1-5
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• 2008

Thirty two of bathroom water samples from public bathroom in Seoul areas were examined using acid-fast staining, Lowenstein-Jensen (L-J) medium culture and PCR-restriction fragment length polymorphism (PCR-RFLP). In 6.25% (2/32) bathroom water samples, acid-fast bacilli were detected by AFB stain, and in 21.9% (7/32) bathroom water samples, acid fast bacilli grew on L-J media. Of them, six acid-fast bacilli were identified as Mycobacterium avium, and the other AFB as Mycobacterium szulgai by PCR-RFLP. These results are suggested that accidental nontuberculosis mycobacterial infection to a weakness person will be possible in public area.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.367-374
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• 2012

A flotation process has a shorter processing time and needs less space than a sedimentation process. Dissolved air flotation process (DAF) is an efficient flotation method and used in a conventional wastewater treatment process. However, DAF requires the circulation of water containing compressed air and requires expensive installation and operation cost. Plasma Air Flotation (PAF) process is able to float flocs by micro bubbles generated from underwater plasma without the circulation of bubbly water and additional saturators. Therefore, PAF can be an alternative solution overcoming economic barriers. In this study, Humic acid removal efficiency by PAF process was compared with that of sedimentation process. 44.67% and 87.3% reduction rate based on UV 254 absorbance has been measured in sedimentation and PAF respectively. In particular, PAF in the flocculation zone can dramatically remove humic acid from water. In flocculation zone, PAF can separate organic matters but sedimentation cannot.

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.122-126
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• 2001

Eleven bacterial strains which were able to utilize terephthalic acid as a carbon and an energy source for growth were isolated from the soil of 7 water quality evaluation points in Kyonggi area of Korea. According to the report from the authorities, biochemical oxygen demands of the water at 4 points were reported over 20 ppm but those of 3 points were repOlted less than 2 ppm in 1997. Optimum temperatures of growth and terephthalic acid degrading activity of some isolates were not identical but optimum growth temperature was 30$^{\circ}$C. Most of the isolates utilized one or two of the phthalate isomers as a carbon source for growth and the isolates from the 4 contaminated points showed higher terephthalic acid degrading activity than those from the 3 clean points.

• Analytical Science and Technology
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• v.9 no.1
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• pp.118-121
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• 1996

56.2% of Aldrich HA was recovered from water by XAD-8 and AGMP-50 procedure. With this method, 0.58mg/l of HA was determined in the water collected from irrigation reservoir near Tae Dok Science Town. For the removal of ash from Aldrich HA, centrifugation was simple, but as effective as dialysis. Neither centrifugation nor dialysis removed Na at all. Only with XAD-8 and AGMP-50 procedure, Na and ash were completely removed.

• Journal of Environmental Science International
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• v.21 no.8
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• pp.1015-1021
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• 2012

Formation of disinfection by-products (DBPs) including trihalomethans (THMs), haloacetic acid (HAAs), haloacetonitriles (HANs) and others from chlorination of algogenic organic matter (AOM) of Microcystis sp., a blue-green algae. AOM of Microcystis sp. exhibited a high potential for DBPs formation. HAAs formation potential was higher than THMs and HANs formation potential. The percentages of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) formation potential were 43.4% and 51.4% in the total HAAs formation potential. In the case of HANs formation potential, percentage of dichloroacetonitrile (DCAN) formation potential was 97.7%. Other DBPs were aldehydes and nitriles such as acetaldehyde, methylene chloride, isobutyronitrile, cyclobutanecarbonitrile, pentanenitrile, benzaldehyde, propanal, 2-methyl, benzyl chloride, (2-chloroethyl)-benzene, benzyl nitrile, 2-probenenitrile and hexanal.