• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.823-826
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• 2008

Statistical methods were used in the analysis of data, which are the SNR and SDNR in describing the various natures, and the methodology relating the results with the operation was developed. Multiple regression analysis based on the results of statistics of data were SNR = 0.0219 + 0.000044BOD lording - 0.00600C/N ratio and SDNR = 0.0226 + 0.000044BOD lording - 0.00602C/N ratio. It were concluded that the variability of the process performance should be reflected to the operation condition procedure through the analysis based on the statistics methods.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.214-221
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• 2009

Denitrification efficiency associated with incorporation of the diffrent carbon substrates with the anaerobic sludge was investigated. For this each kinetic constant such as methane reaction and specific denitrification rate (SDNR) were determined in each treated sludge. In the pure methanogenesis, the specific methanogenesis activity (SMA) value was the highest at $0.76COD/g\;VSS{\cdot}day$ when the acetate was incorporated with the anaerobic sludge which has already been adapted at consistent C/N ratio 5 for reatively higher denitrifier population. The anaerobic dinitrificaition and methanogenesis reaction were dependent on both the types of carbon substrate and sludge showing the higher denitrificaition reaction constant at $1.96hr^{-1}$ with incorporation of acetate with the anaerobic sludge at C/N ratio 5 than any other carbon sources examined. When the glucose was introduced as electron donor for the anaerobic sludge adapted with different carbon substrates the SDNR showed the highest value with the sludge adapted to glucose followed by the sludge adapted to piggery sludge and acetate.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.151-158
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• 2015

The aim of this research is to derive an optimum operating condition for the thermal solubilization equipment that is employed to increase concentration of soluble organic materials and to assess whether it would be possible to use the waste sludge generated by thermal solubilization reaction as an external carbon source in biological denitrification process. For the purpose, we have constituted a laboratory-size thermal solubilization equipment and have assessed thermal hydrolysis efficiency based on various reaction temperature and reaction time. We have also derived SDNR using the waste sludge generated by thermal solubilization reaction through a batch experiment. As a result of research, the highest thermal hydrolysis efficiency of about 42.8% was achieved at $190^{\circ}C$ of reaction temperature and at 90 minutes of reaction time. And when SDNR was derived using the waste sludge, the value obtained was $0.080{\sim}0.094\;g\;NO_3{^-}-N/g\;MLVSS{\cdot}day$, showing SDNR that is higher than that obtained by the results of existing researches that used common wastewater as an external carbon source. Accordingly, in view of the fact that food wastes vary quite a bit in characteristics based on the area they are generated from and seasonal change, it seems that a flexible operation of thermal solubilization equipment is required through on-going monitoring of food wastes that are imported to food wastes recycling facilities.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.79-86
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• 2016

The purpose of this study is to efficiently improve biological sequencing batch reactor (SBR) system of high-concentrated nitrate nitrogen in reverse osmosis (RO) concentrates by total dissolved solids (TDS) regulation. Since a laboratory-scale SBR system had been operated, we had analyzed specific denitrification rate (SDNR) and specific oxygen uptake rate (SOUR) for microbial activity in according to various injection concentration of TDS. As a result, higher injection concentration of TDS decreased SDNR, and delayed denitrification within denitrification process. Moreover, the higher injection concentration of TDS was, the lower microbial activity was during operation of laboratory-scale SBR system. Therefore, the regulation of TDS injection concentration is necessary to improve efficiency of nitrate nitrogen in the biological SBR system, and treatment of calcium ion ($Ca^{2+}$) is also specifically focused to remove nitrate nitrogen. Moreover, analytical data of SDNR and SOUR can be the effective kinetic design parameters to application of biological treatment of RO concentrate by aerobic granular sludge (AGS).

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.739-745
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• 2005

Simultaneous denitrification and methanogenesis at various influent COD/Nitrate-N(below C/N) ratio was investigated with two different anaerobic sludges of which one was inoculated with glucose only and the other was inoculated with glucose and nitrate. Three different C/N ratios of 30, 20, and 10 were applied with each anaerobic sludge in serum bottles agitated in a rotary shaker to monitor the time related changes of amount of gas production and gas composition. Glucose was used as a single carbon source, which was adjusted to 1,000 mg/L as COD and potassium nitrate was used as a nitrogen source to adjust the each C/N ratio. COD removal by methanogenesis was dominant at higher C/N ratios, while COD removal by denitrification was dominant at lower C/N ratios. With the sludges cultured at C/N ratios below 10, SMA and SDNR rising different carbon substrates were investigated. The most efficient carbon substrate was acetate and the highest SMA and SDNR were 0.76 g COD/g VSS day with pure anaerobic sludge and 1.38 g ${NO_3}^--N/g$ VSS day with sludge cultured at C/N ratio of 5, respectively.

• Korean Journal of Microbiology
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• v.54 no.2
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• pp.105-112
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• 2018

To compare the denitrification efficiency, this study used molasses and methanol were used as external carbon sources. Specific experimental conditions were classified according to C/N ratio conditions. The batch test showed that the denitrification efficiency increased as C/N ratios of molasses and methanol rose. The most suitable C/N ratio of molasses turned out 4:1 considering the concentration of the residue chemical oxygen demand (COD) and the denitrification efficiency, which was 91.4%. Specific denitrification rate (SDNR) drawn as a kinetic factor demonstrated that molasses and methanol showed similar SDNR values as C/N ratios of molasses and methanol increased. Under the condition of C/N ratio 4:1, 0.0292 g $NO_3{^-}-N$ removal/g mixed liquor volatile suspended solid (MLVSS)/day (molasses), 0.0299 g $NO_3{^-}-N$ removal/g MLVSS/day (methanol) were found. Sludge adapted to molasses showed that Bacterium Pseudomonas sp. and Bergeylla sp. dominated through an analysis of microbial community. In addition, some bacteria were high convergences than the variety of microbial community. Accordingly, it was assumed that molasses focus on growing microorganisms specialized in denitrification and applied as a replaceable external carbon source that can enhance denitrification performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.143-147
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• 2016

Recently, digital tomosynthesis system (DTS) has been developed to reduce overlap using conventional X-ray and to overcome high patient dose problem using computed tomography (CT). The purpose of this study was to develop image reconstruction algorithm and to evaluate image characteristics and dose with chest digital tomosynthesis (CDT) system. Image reconstruction was used for filtered back-projection (FBP) methods and system geometry was constructed ${\pm}10^{\circ}$, ${\pm}15^{\circ}$, ${\pm}20^{\circ}$, and ${\pm}30^{\circ}$ angular range for acquiring phantom images. Image characteristics carried out root mean square error (RMSE) and signal difference-to-noise ratio (SDNR), and dose is evaluated effective dose with ${\pm}20^{\circ}$ angular range. According to the results, the phantom image with slice thickness filter has superb RMSE and SDNR, and effective dose was 0.166 mSv. In conclusion, we demonstrated usefulness of developed CDT image reconstruction algorithm and we constructed CDT basic output data with measuring effective dose.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.322-328
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• 2011

This study was performed to investigate the characteristics of nutrient removal of municipal wastewater in the membrane bioreactor system with the different types of membrane. Membrane bioreactor consists of three reactors such as two intermittent anaerobic and the submerged membrane aerobic reactor with flat sheet and hollow fiber membrane, respectively. The removal efficiencies of $COD_{cr}$, BOD, SS, TN and TP on the flat sheet membrane bioreactor were 94.3%, 99.0%, 99.9%, 70.3% and 63.1%, respectively. In addition, The removal efficiencies of $COD_{cr}$, BOD, SS, TN and TP on the hollow fiber membrane bioreactor were 94.0%, 99.3%, 99.9%, 69.9% and 66.9%, respectively. The estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR) and phosphorus removal content on the flat sheet membrane bioreactor were $0.33kgVSS/kgBOD{\cdot}d$, $0.043mgNO_3-N/mgVSS{\cdot}d$, $0.031mgNH_4-N/mgVSS{\cdot}d$, and 0.144 kgP/d, respectively. In addition, the estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR) and phosphorus removal content on the hollow fiber membrane bioreactor were $0.30kgVSS/kgBOD{\cdot}d$, $0.067mgNO_3-N/mgVSS{\cdot}d$, $0.028mgNH_4-N/mgVSS{\cdot}d$, and 0.121 kgP/d, respectively. There was little difference between the flat sheet and hollow fiber on the nutrient removal efficiencies except SNR and SDNR. These differences between them were caused by the air demand to prevent the membrane fouling. The flux and oxygen demand for air scouring were $19.0L/m^2/hr$ and $2.28m^3/min$ for the flat sheet membrane, and $20.7L/m^2/hr$ and $1.77m^3/min$ for the hollow fiber membrane on an average.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.5
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• pp.521-529
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• 2007

Nutrient removal from synthetic wastewater was investigated using a MLE (Modified-Ludzack Ettinger) type MBBR (Moving Bed Biofilm Reactor), with different phenol ($C_6H_5OH$) concentrations, in order to determine the inhibition effects of phenol on biological nutrient removal and the biodegradation of phenolic wastewater. The wastewater was prepared by mixing a solution of molasses with known amounts of phenol and nutrients. The experiments were conducted in a lab-scale MLE type MBBR, operated with four different phenol concentrations (0, 67, 100 and 168mg/L) in the synthetic feed. Throughout the experiments, the ratio of the phenolic COD concentration to the total COD was varied from 0 to 1. Throughout batch test, the SNR (Specific Nitrification Rate) and SDNR (Specific Denitrification Rate) were significantly influenced by changes of the phenol concentration. Phenol was inhibitory to the nitrification/denitrification process, and showed greater inhibition with higher initial phenol concentrations. The SNR observed with 0, 67, 100 and 168mg phenol/L were very different like 10.12, 6.95, 1.51 and $0.35mg\;NH_{3^-}N/gMLVSS$ hr, respectively. Similarly, the SDNR observed at 0, 67, 100 and 168mg phenol/L were different like 0.322, 0.143, 0.049and 0.006mgN/gMLVSS day, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.907-915
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• 2011

In this study, the SBR and MLE process was performed for a removal of the RO retentate and the nitrogen removal efficiency was evaluated. The inflow-rate of two processes was set a 10 L/day. The SBR process was operated a two cycle as HRT per one cycle was 12hr and the HRT of the anoxic and aerobic tank was respectively 7.5 hr and 16.5 hr. The methanol was injected for an effective denitrificaion owing to a low C/N ratio of the RO retentate. The two processes were effectively performed for nitrogen removal, but the average removal efficiency of the SBR process was about 94.93% better performance than the MLE process. Therefore, the SBR process demonstrated a good performance more than the MLE process for nitrogen removal of the RO retentate. The kinetic of SNR and SDNR was observed respectively 0.051 kg $NH_{3}-N/kg\;MLVSS{\cdot}dayg$ and 0.287 kg ${NO_3}^--N/kg\;MLVSS{\cdot}day$, which will be useful to design for the wastewater treatment system with a RO retentate.