• Journal of Life Science
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• v.15 no.4 s.71
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• pp.590-594
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• 2005

In this study, the wastewater treatment was conducted to evaluate the removal efficiency of total nitrogen from synthetic wastewater in the F-STEP PROCESS $(anaerobic{\rightarrow}\;oxic\;{\rightarrow}\;anoxic)$ with loess ball as support metrics. The average removal efficiencies of total nitrogen and ammonia nitrogen were $83.0\%\;and\;84.4\%$, respectively. The average nitrification efficiency at the oxic area was $60.9\%$ in the pH range of effluent water between 4.8 and 6.0. On the other hand, in the case of pH range of effluent water between 6.5 and 7.5, the denitrification efficiency at the anoxic area was $96.3\%$. The average concentration of COD was 12.8 ppm and the removal efficiency of COD in the F-STEP PROCESS were $96.3\%$. In the case of SS, the average concentration was $7.0\%$ at the effluent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.21-26
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• 2002

The behavior of the biological water treatment process on start-up operation was evaluated in the integrated recirculating aquaculture system consisting of a double drain type rearing tank ($2.5 m^3$), a sedimentation tank, a floating bead filter, a foam separator and a rotating biological contactor. A system was stocked with nile tilapia (Oreochromis niloticus) at an initial rearing density of $2\%$ for 2 weeks for acclimated rotating biological contactor. The total ammonia nitrogen (TAN) level increased to $13.6 g/m^3$ on day 4 after adding feed and was decreased to $0.3 g/m^3$ on day 7. The total suspended solid was completely removed during overall experimental period.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.11-20
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• 1998

Inorganic nitrogens resulting from fertilizers are possible contaminants of bank-filtered ground water, which is an alternative source of safe drinking water. We conducted a laboratory study to determine the fate of inorganic nitrogens in the near field of bank filtration sites and we consequently illustrated the effects of these possible contaminants on the water quailty of bank filtration. Soil properties were found to be well equivalent to those of other cultivated field soils in Korea. Surface soil pH was about 4.3 which is slightly lower than average level. Overall, diverse concentrations of $NO_3$-N and $NH_3$-N were measured, and $NO_2$-N was nearly undetected. $NH_3$-N level in the field decreased, while $NO_3$-N increased along with increasing depth of unsaturated zone. Numbers of viable and nitrifying bacteria ranged from 6.73$\times$$10^{6}$to 10.7$\times$$10^{6}$ and 0.44$\times$$10^{4}$ to 5.21$\times$$10^{4}$ respectively, and both of them were highly correlated ($R^{2}$=0.992). Nitrifying potential assayed by batch test showed relatively lower than other reported results. The oxygen uptake potential of surface and subsurface soil was measured in the presence of ${(NH_4)_2}$$SO_4$. The results demonstrated that surface soil required shorter lag period and uptaked more oxygen than subsurface's.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1085-1089
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• 1998

The well-established nitric acid-sulfuric acid mixed acid process for the nitration of aromatic compounds has serious problems due to the large amount of waste acids and severe reaction conditions. Nitration of toluene can be conducted using nitrogen dioxide and ozone instead of mixed acid. We found that conc. nitric acid increased the reactivity as catalyst and the amount of nitrogen dioxide controlled the extent of nitration. Dinitration proceeded to more than 92 mole % conversion within 2 hr at $0^{\circ}C$ with 6 eq. of nitrogen dioxide and 2 eq./hr of ozone flow. Toluene completed mononitration within 30 min using 3 eq. of nitrogen dioxide, 3 eq. of nitric acid, and 1.5 eq./hr of ozone flow. As a clean process of aromatic nitration, this method is expected to replace the present process which causes the environmental problems.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.4
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• pp.128-135
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• 2005

This study was done to improve the effectiveness of nitrification and denitrification using the aeration-anoxic combination method using CFSTR(continuous-flow stirred-tank reactor) attached with an anoxic reactor filled with a media. In order to calculate the concentration of nitric acid within the aeration tank proportional to the anoxic rate within the reactor, supernatant within the inflow and precipitation tanks were influxed into the anoxic reactor. The rate of nitrogen removal was calculated using the concentration of inflow and flow of returned supernatant. From the results of this experiment, the carbon source needed in the anoxic reactor came from the inflow so that anoxification was achieved completely using the inflow source without the introduction of an external carbon source. However, as the ratio of nitric acid becomes large in inflow and nitric acid flow, the carbon source within the input source decreases so that the concentration of carbon source is important.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.282-287
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• 1996

This study was conducted to identify the parameter better representing the nitrogen supply capacity of soils for the vegetable crops growing in vinylhouse. All the parameters showed significant positive correlation with the yield of chinese cabbage. The correlation coefficients were in the order of $NO{_3}^--N+NH{_4}^+-N(2M\;KCl)$ > $NO{_3}^--N(2M\;KCl)$ > OM > T-N > 0.01M $NaHCO_3$ > 0.01M $CaCl_2$ > $NH{_4}^+-N(2M\;KCl)$ > 6N HCl. Between the soil N and N absorbed by plant, the correlation coefficients were in the order of $NO{_3}^--N+NH{_4}^+-N(2M\;KCl)$ > $NO{_3}^--N(2M\;KCl)$ > 0.01M $NaHCO_3$ > $NH{_4}^+-N(2M\;KCl)$ > 0.01M $CaCl_2$ > OM > T-N > 6N HCl. The results of this study suggest that 2M KCl extractable inorganic N. 2M KCl extractable $NO{_3}^--N$ are recommendable parameters for the estimation of N supply capacity of the vinylhouse soils. The sum of soil $NO{_3}^--N$ and fertilizer nitrogen showed highly significant positive correlation with the yields of chinese cabbage and nitrogen absorbed by the plant, while negative correlation with the nitrogen use efficiency.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.223-224
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• 2000

대하 양식장과 같이 물의 유동이 작고, 폐쇄성이 강한 지역, 더구나 유기물 혹은 질소, 인등의 영양염류 농도가 높은 부영양화 지역에서는 저질 중의 유기물 분해에 따른 산소소비는 저질환경을 산화상태로부터 환원상태로 이동시켜 황산염 환원에 의한 황화수소가 발생한다. 따라서 황화수소의 발생은 용존산소의 저하를 나타냄과 동시에 그 자체가 강한 독성을 가지고 있으며, 질소화합물 중의 암모니아 및 아질산과 같은 형태도 양식장의 생산억제 요인으로 작용한다(Gavis and Grant, 1986; Thompson et al., 1989). 그러나, 지금까지의 이들 오염물질, 특히 황화수소에 대한 연구는 미비하며, 대부분의 연구도 성체를 중심으로 이루어지고 있다. (중략)

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.89-93
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• 2011

This study was conducted to evaluate the effects of bastnasite nitrate fertilizer (BNF) on the growth of creeping bentgrass. Fertilizer treatments were designed as follows; non-fertilizer (NF), control (CF; compound fertilizer), RE-l (CF+0.3 $g{\cdot}m^{-2}$BNF), RE-2 (CF+0.5 $g{\cdot}m^{-2}$BNF), RE-3 (CF+1.0 $g{\cdot}m^{-2}$BNF) and RE-4 (0.5 $g{\cdot}m^{-2}$BNF). Every treatment was arranged in a randomized complete block design with three replications. In creeping bentgrass, turf qualities such as turf color index and chlorophyll index, shoot number, clipping dry weight and nutrients of tissue were measured. It was hardly affected by BNF application in investigation of chemical properties of the soil. By applying BNF, turf color index and chlorophyll index in RE-2 were increased 3.9% and 9.2% more than NF. As applied BNF on creeping bentgrass, shoot number was increased 9% in RE-4 more than NF and 22% in RE~2 more than CF. It was increased in N uptake and clipping dry weight of creeping bentgrass by supplying BNF. These results indicated that the BNF application promoted a turf qualities and a growth of creeping bentgrass by advancing N uptake and shoot number.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.421-427
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• 2015

In ASM model, organic matters are classified according to their characteristics and general classification into COD and BOD cannot satisfy conditions required by ASM. In this study, it was performed to study classification of organic matters required by ASM on the basis of microorganisms' respiration rate subject to wastewater and sludge treatment. As results of analysis of the organic matter's appearance, it was found that there were some differences in composition of organic matters between wastewaters. It is considered that it is an important characteristic of wastewater that should be understood in treating wastewater in each process. Therefore, it is considered that appearance of organic matters in each wastewater identified by this study will be used as important basic data for operation of municipal wastewater treatment plant. It was identified that SS was an important factor affecting nitrification through organic matter and ammonium nitrogen change analysis according to reaction time in the nitrification. It is considered that the nitrification has close relationship with choice of optimal retention time.

• Journal of the Korean GEO-environmental Society
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• v.5 no.2
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• pp.23-31
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• 2004

Trichloroethylene(TCE), Cr(VI), and nitrate removal efficiency of a novel reactive barrier were experimented, and the types of corrosion species that form on the surface of the iron and bentonite as a result of reaction were investigated with Raman spectrophotometer. The reactive barrier is composed of bentonite and zero valent iron(ZVI), and this can substitute conventional geosynthetic clay liners for landfill leachate. Tests were performed in batch reactors for various ZVI content (0, 3, 6, 10, 13, 16, 20, 30, 100 w/w %) and pH. The reduction rates and removal efficiencies of TCE, Cr(VI) and nitrate increase at pH 7 buffered solution. As ZVI content increases, TCE, Cr(VI) and nitrate removal efficiencies increase. From the result of analysis with Raman spectrophotometer, Fe-oxides were observed, which are strong adsorbers of cantaminants. Magnetite can be also beneficial to the long term performance of the iron metal.