• Applied Biological Chemistry
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• v.45 no.2
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• pp.84-91
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• 2002

If contaminated river water is sprayed over the floodplain, organic matter and nitrogen would be removed by microbial processes in the rhizosphere of vegetation during the filtration through soil. In this study we tested the organic matter and nitrogen removal from contaminated river water by the floodplain filtration. Model system of floodplain was constructed using a PVC pipe (15 cm i.d. ${\times}$ 150 cm L) which was packed with a loamy sand soil collected from a floodplain in Nakdong river. The model system was instrumented with soil solution samplers and gas samplers. A river water collected from Omogcheon in Kyongsan was sprayed from top of the model system at three different rates. The concentration of organic matter, DO, $NO_3^-$, $NO_2^-$, $NH_4^+$, $N_2$ and $N_2O$, and redox potential were measured as a function of soil depth for 24 days after the system reached a steady state. When river water was sprayed at the rates of 40.8 and 68.0 $l/m^2/day$, a significant reductive condition for denitrification was developed at below 5-cm depth of the soil. When the water reached at 90-cm depth of the soil, COD and concentration of inorganic nitrogen were lowered, on an average, from 18.7 to 5 mg/l and from 2.7 to 0.4 mg/l, respectively. $N_2$ comprised most of the N gas evolved from denitrification and $N_2O$ concentrations emitted at the surface of soil were less than 1 {\mu}l/l. The effective removal of organic matter and nitrogen by the filtration in the model system of floodplain demonstrates that the native floodplains, which include rhizosphere of vegetation at the top soil, could be more effective in the treatment of contaminated river waters and other industrial waste waters containing high concentration of organic matter and nitrogen.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.162-168
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• 1990

The aims of the present study were to evaluate the effects of culture conditions on the biosynthesis of extra-cellular alkaline protease in Streptomyces sp. The formation of aerial mycelia and spores were compared with the protease production in order to know the relations between the alkaline protease and the cell differentiation. As results, it was found that substrate concentration was very critical to regulate the formation of the protease, aerial mycelia, and spores, which were resulted from the changes of culture pH to acid. When the culture pH was adjusted with phosphate buffer from pH 6 to pH 9, the alkaline protease production was increased as the culture pH increased whereas aerial mycelia and spore formation were reversely related to the culture pH. Therefore, it was thought that the culture pH was an important factor to regulate the alkaline protease synthesis.

• Applied Biological Chemistry
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• v.21 no.1
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• pp.31-34
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• 1978

The stability of active ingredient of BPMC formulation under ultraviolet lights and sunlights was investigated using dust, emulsifiable concentrate and granular. The active ingredient of BPMC dust was more rapidly degraded by irradiation with ultraviolet lights than emulsifiable concentrate or granular tested. In the case of BPMC emulsions, the degree of degradation was increased in the order of granular, emulsifiable concentrate, dust by irradiation with ultraviolet lights. BPMC was unstable in alkaline solution and ultraviolet lights had highly significant relation to the decomposition of its active ingredient.

• The Korean Journal of Mycology
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• v.17 no.3
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• pp.149-153
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• 1989

One strain of Aspergillus niger K-25 producing an acid-stable ${\alpha}-amylase$ was isolated from the soil. The optimum culture conditions were investigated. The production of the acid-stable ${\alpha}-amylase$ was enhanced when the strain was incubated in a medium containing soluble starch 3.5%, peptone 2%, $KH_2PO_4$ 0.5%, $MaSO_4{\cdot}7H_2O$ 0.25% and $FeCI_3$ 1.0% at pH 3 for 7 days. However, higher activity of acid-stable ${\alpha}-amylase$ was demonstrated on wheat bran culture. Amylase production was doubled when A. niger K-25 was incubated on the wheat bran supplemented with fumaric acid buffer (pH 3).

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.40-44
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• 1998

A Penicillium strain which produces $eta$-galactosidase with high transgalactosylation activity, was isolated from soil and registered as Penicillium sp, KFCC 10888. When $eta$-galactosidase from Penicillium sp. KFCC 10855 reacted with 40% lactose, transgalactosylation ratio reached up to 70% at the 73% conversion of initial lactose. The biosynthesis of the enzyme in Penicillium sp. KFCC 10888 was not induced by lactose. The soybean meal was an effective component of the culture medium. The optimum pH and temperature for transgalactosylation were 4.0 and 55$^{\circ}C$, respectively. The production of galactooligosaccharides was in proportion to the initial lactose concentration. When the enzyme reacted with 40% lactose (pH 4.0) at 55$^{\circ}C$, the concentration of galactooligosaccharides increased up to 40% of total solid concentration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.156-159
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• 2002

Ion exchange is the most reliable process to remove the ionic impurities and the economic operation. ion exchange is widely used in water and wastewater treatment, especially softening and demineralization. ion selectivity depends on the hydrated radius, charge of ions and concentration. The objective of this study was to determine the selectivity order of cations with equilibrium and column ion exchanges and to investigate the effect of the background anion on selectivity. Cation selectivity increases with decreasing concentration and increasing charge ( $H^+$ < $K^+$ << $Cu^{2+}$ < $Co^{2+}$ < TEX>$Ca^{2+}$ << $Ce^{3+}$)in equilibrium and column cation adsorptions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3C
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• pp.143-148
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• 2008

This paper demonstrates settling and further consolidation behaviour of dredged clayey soils during landfilling. The effects of initial moisture content, electrolyte type and concentration on settling and consolidation behaviour were examined and evaluated by laboratory column tests. Electrokinetic tests were carried out with modified settling column to compare the soil behaviour under the gravity. From the testing results, the settling velocity increased due to the effects of cations in the electrolyte solution, and electrically induced settlements were found to be greater than those under the gravity.

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.86-93
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• 2007

In recent tests using tracer have been frequently conducted by fluorescent tracers. In this study, granular activated charcoal (GAC) as a detector for the fluorescent tracers (rhodamine WT and uranine) was investigated through laboratory and field tests. In the laboratory tests, tracer concentrations of rhodamine WT and uranine determined by the GAC were slightly different from those of standard solutions but they were excellent in linearity. Results show that GAC is excellent as tracer detector when concentration of the fluorescent tracers is greater than 10 & micro; g/L whileas no obvious differences in mixed solutions of the two tracers due to interferences. Compared to conventional methods of water sampling, field results shows a high potential of GAC as a tracer in the field. Our results also show that wet analysis is better for the lower concentrations of tracers whileas dry analysis is good for high concentrations of tracers. This study demonstrates that fluorescent tracer detection using the GAC is very useful and economical for a hydraulic connection between target areas and very longer period of the tracer test.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.62-69
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• 2008

In this study physicochemical characteristics and stability of various manganese coated sands (MCS) prepared with different methods were evaluated. In addition, removal efficiencies of As(III) by each MCS were compared. Four different MCSs were used; B-MCS prepared by baking method, W&D-MCS prepared by wetting and dry method, NMCS prepared during the water treatment process and Birm which is a commercial MCS widely used for the removal iron and manganese. The manganese content in each MCS was following order: Birm (63,120 mg/kg) > N-MCS (10,400 mg/kg) >W&D-MCS (5,080 mg/kg) > B-MCS (2,220 mg/kg). Birm showed the least solubility (% basis) in acidic conditions. As(III) oxidation efficiency of B-MCS was continuously increased as the solution pH decreased. While As(III) oxidation efficiency of N-MCS and Birm was minimum around neutral pH. The increased As(III) oxidation efficiency above neutral pH for N-MCS and Birm could be due to the competitive adsorption of $Mn^{2+}$, which was produced from reduction of $MnO_2$, onto the surface of aluminum and manganese oxides.

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.61-69
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• 2005

Changes in pyrene binding by dissolved and kaolinite-associated humic substances (HS) due to HS adsorptive fractionation processes were examined using purified Aldrich humic acid (PAHA) at different pH (4, 7 and 9). Irrespective of solution pH, molecular weight (MW) fractionation occurred upon adsorption of PAHA onto kaolinite, resulting in the deviation of residual PAHA MW from the original MW prior to sorption. Variation in $K_{OC}$ by bulk PAHA was observed at different pH due to relative contributions of partitioning and size exclusion effects (i.e., specific interactions). For all pH conditions investigated, carbon-normalized pyrene binding coefficients for nonadsorbed, residual fractions $(K_{OC}(res))$ were different from the original dissolved PAHA $K_{OC}$ value $(K_{OC}(orig))$ prior to contact with the kaolinite suspensions. Positive correlations between pyrene $(K_{OC}(res))$ and weight-average molecular weight $(MW_W)$ for residual PAHA fractions were observed for pH 7 and 9. However, such a positive correlation was not found at pH 4 due to the absence of the dramatic fractionation observed for high pH conditions (i.e., exclusive fractionation with respect to higher MW), suggesting that actual MW distribution pattern is more important for sorption-fractionated HS than the composite MW value. For adsorbed PAHA, conformational changes of PAHA upon adsorption seem to be important for the extent of pyrene binding. At relatively high pH (7 and 9), lower extent of pyrene binding was observed for adsorbed PAHA versus nonadsorbed PAHA. The conformation effects were more pronounced at higher pH.