• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.113-120
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• 2004

The biodegradability of organics has become essential for the design and modeling of a biological nutrient removal process. Respirometry for the batch test just with wastewater has been conducted to estimate active biomass and readily biodegradable organics in municipal wastewater simultaneously. Municipal wastewater contains significant active biomass, which is estimated about 17% of COD. Compared to the batch test seeded with sludge, the batch test just with wastewater represents a little higher readily biodegradable organics. This might be due to the different environment of the logarithmic growth of active biomass. The nitrate uptake rate test has been also performed for the estimation of the readily biodegradable organics. The nitrate uptake rate test results in a little higher readily biodegradable organics compared to the batch test seeded with sludge and similar organics compared to the batch test just with wastewater. This might be caused by the different sludge of a sequencing batch reactor process. Taking the result of the previous research into account, the readily biodegradable, slowly biodegradable, active biomass, soluble inert, and particulate inert organics are estimated about 11%, 49%, 17%, 11%, and 12% of COD, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.5
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• pp.543-550
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• 2015

In this study, using soil brick with combined effective microorganisms and emergent plants was identified which it can increase the effect of conservation and improvement of water. Lab-test was consist of four kind of reactors and each of reactors were A(rawwater), B(soil brick), C(emergent plant) and D(soil brick+emergent plant). Iris pseudoacorus, Phargmites australis, Typha angustifolia and Zizania latifolia were used for emergent plant. Evaluation of application on various environment were performed on agricultural waterway and pond. The pH measurement test of soil brick was performed due to evaluate whether a strong alkaline water flows out of the soil brick. Result of lab-test, removal efficiency of D was better than removal efficiency of A presenting 20.9%, 27.9% 21.5%, 33.8% and 58.4% for $COD_{Cr}$, $BOD_5$, TN, TP and TSS respectively. Removal efficiency of soil brick on agricultural waterway was revealed to be 49.5%, 45.0%, 43.7%, 37.3% and 28.6% for $COD_{Cr}$, $BOD_5$, TN, TP and TSS respectively. And removal efficiency of soil brick on the pond was revealed to be 12.7%, 10.5%, 9.32%, 10.4% and 36.3% for $COD_{Cr}$, $BOD_5$, TN, TP and TSS respectively. Result of pH measurement test of soil brick was neutral which was about 6 to 8.

• Journal of Life Science
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• v.21 no.4
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• pp.554-560
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• 2011

This study was performed to investigate the effects of microbial augmentation on the biological treatment of paper mill wastewater. Three bacteria (KN11, KN13, KN27) capable of degrading aromatic compounds and a bacterial strain (GT21) producing an extracellular cellulase were isolated from soil and wastewater by selective enrichment culture. Through morphological, physiological, and biochemical taxonomies, isolated strains of KN11, KN13, KN27, and GT21 were identified as Acinetobacter sp., Neisseria sp., Bacillus sp., and Pseudomonas sp. and named Acinetobacter sp. KN11, Neisseria sp. KN13, Bacillus sp. KN27, and Pseudomonas sp. GT21, respectively. For analysis of non-biodegradable and chemical oxygen demand (COD)-increasing matter in a paper mill wastewater, we utilized GC/MS to detect aromatic compounds and their derivatives containing several substituted functional groups. The microbial augmentation, J30 formulated with the mixture of bacteria including Acinetobacter sp. KN11, Neisseria sp. KN13, Bacillus sp. KN27, and Pseudomonas sp. GT21, was used for the treatment of paper mill wastewater. The optimum temperature and pH for COD removal of the microbial augmentation, J30, were $30^{\circ}C$ and 7.5, respectively. For evaluation of the industrial applicability of the microbial augmentation, J30 in the pilot test, treatment efficiency was examined using paper mill wastewater. The microbial augmentation, J30, showed a COD removal rate of 87%. On the basis of the above results, we designed the wastewater treatment process of the activated sludge system.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.3
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• pp.27-39
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• 2019

In this study, thermal-alkali pre-treatment (THAP) optimal condition and co-digestion efficiency with THAP of the mixture food waste and sewage sludge were evaluated for improving the performances of co-digestion for mixed food waste and sewage sludge. The optimal condition of THAP was evaluated for solubilization COD, CST(Capillary Suction Time), TTF(Time to Filter), and volatile fatty acids (VFAs) with THAP temperature and NaOH concentration. In addition, the co-digestion of mixed food waste and sewage sludge were evaluated using biochemical methane potential (BMP) test. The optimal THAP reaction temperature and NaOH concentration of food waste and sewage sludge were $140^{\circ}C$ and 60 meq/L to solubilization COD over 20%, CST and TTF under 60sec and VFAs concentration over 12,000 mg-COD/L, respectively. The optimal condition of co-digestion of mixed food waste and sewage sludge equal to THAP condition. Therefore, it was determined that the optimal condition of THAP reaction temperature and NaOH concentration for co-digestion of mixed food waste and sewage sludge were $140^{\circ}C$ and 60 meq/L, respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1568-1575
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• 1990

Fatigue crack growth behavior was investigated in the center cracked plate of KS SB41 steel and the relation between the crack growth rate and various mechanical parameters was studied at small scale yielding, large scale yielding and full scale yielding. The crack opening ratio U was about 0.6-0.8 and had the larger value in the case of load control than that of strain control. Effective stress intensity factor range, .DELTA.K$_{eff}$ and J integral range, .DELTA.J were obtained from the notion of crack opening, and the crack growth rate was expressed with these values. The value of J integral range increased rapidly at stress ratio, R=0 in full scale yielding of load control test. COD value also increased rapidly with the increase of ligament net stress at large scale yielding of load control test.t.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.247-253
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• 2007

Polycyclic aromatic hydrocarbons (PAHs) are a major concern because of their potential mutagenic and carcinogenic risks to human beings. One of these harmful, yet commonly observed PAHs is pyrene. Pyrene is one of the 16 PAHs listed by the United States Environmental Protection Agency as priority pollutants. The purposes of this research are to develop a method of pretreatment for PAH contaminants prior to a typical biological treatment and to demonstrate the biodegradablity of these compounds. Since pyrene is non-polar, hexane was chosen as a solvent to effectively dissolve pyrene. Pyrene solutions were treated with ozone, as it has hish oxidation capacity and electrophilic character. The intermediates and byproducts of pyrene were dissolved in alkaline water at pH 11.4 and neutralized to test for $BOD_5$, COD, and toxicity. These solutions were further ozonated and assessed of biodegradability. The first-order rate constant to was found to be between $0.121day^{-1}$ and $0.081 day^{-1}$, depending on the duration of reozonation. The $BOD_5/COD$ ratio was found to 0.66. The toxicity test showed that after 10 min of reozonation time, the byproducts and intermediates of pyrene were within the lion-toxic range of ${\pm}10%$ inhibition for E-Coli bacteria.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.2
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• pp.35-46
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• 2020

In this paper, a fracture mechanics evaluation system which can be used to assess the leak-before-break (LBB) of nuclear piping is developed. Existing solutions for calculating the fracture mechanics parameters (J-integral and crack opening displacement) required for LBB evaluation were firstly presented. Then a module for calculating J-integral and COD was developed, with an additional module for predicting the critical load based on the crack driving force diagram to finally develop a fracture mechanics evaluation system. To confirm the validity of the proposed evaluation system, finite element (FE) analysis was performed, and the FE J-integral and COD results were compared with prediction results using the J-integral and COD estimations program. Furthermore, the critical load assessment module was verified by comparing the actual pipe test results (Battelle test data) with prediction results using the proposed program.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.1
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• pp.13-21
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• 1996

For treating tannery wastewater containing high sulfate and heavy metals, test was performed to assess their performance, competition between SRB (sulfate reducing bacteria) and MPB (methane producing bacteria), and the activity of MPB according to change of chromium concentrations. COD removal efficiency was above 70% at VLR (volumetric loading rate) of 2.0 gCOD/I.day and HRT (hydraulic retention time) of 18hrs at $35^{\circ}C$. In the competition between SRB and MPB, about 15% of the removed COD was utilized by SRB in the begining, but it became 43% at the end. It indicated that MPB was strongly suppressed by the occurrence of significant sulfate reduction since a large electron flow was uptaken by SRB. For the entire experiment, removal efficiencies of chromium concentration were more than 90%. Despite high removal efficiencies of chromium concentration, performance of reactor did not change significantly during the experimental periods. Expecially, chromium (III) is tannery wastewater is less toxic than chromium (VI).

• Journal of Environmental Science International
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• v.7 no.1
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• pp.81-88
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• 1998

This study was conducted to assess the characteristics of plgment wastewater and the removal rates of appropriate treatment by physical, chemical and biological Process, and the possibility of reuse for effluent. Based on the results, the wastewater qualities of pigment were pH 5.1$\pm$3.4, temperature 43.0$\pm$ 15.$0^{\circ}C$, BOD 1,431.4$\pm$589.6mg/l, COD 2,282.8$\pm$466.5mg/l, turbidity 1,340$\pm$820NTU, color 243.0$\pm$147.0unit, Pb 36.5$\pm$9.5mg/l and $Cr^+6$ 10.3$\pm$ 1.3mg/l, respectively. The removal rates of adsorption by activated carbon and filter process were BOD 40.6% , COD 57.0% , turbidity 89.6%, color 87.2%, Pb 86.0% and $Cr^+6$ 10.6%, respectively. And the removal rates of reduction, neutralization, coagulation and aP floatation process were BOD 18.2%, COD 24.3%, turbidity 74.3%, color 56.7%, Pb 68.6% and $Cr^+6$ 97.8%, respectively. The removal rates of activated sludge process were BOD 95.9%, COD 86.0%, turbidity 27.8%, color 25. 2%. Pb 26.9% and $Cr^+6$ 50.0% , respectively. The total removal rates of treatment by physical, chemical and biological process were BOD 98.0% , COD 95.4%, turbidity 98.1%, color 95.8%, Pb 97.0% and $Cr^+6$ 99.0%, respectively. According to the test results for possibility of reuse with coagulation-adsorption by activated carbon process of effluent, COD was higher than that of raw water and others were similar to that of raw water thus, it Is considered to be reused.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.75-82
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• 2007

Washed wastewater generated from the intermittent cleaning process of the three tunnel sites located in the Seoul area showed high concentrations of SS, $COD_{Cr}$, T-N, $NH_3-N$, $NO_3-N$, Zn, Cu, Cr(+6), Mn, Mg, Phenol, $CN^-$ and E-Coli based on the water quality analysis. These characteristics of the deteriorative wastewater depend on the sampling method, cleaning frequency, released amount of washing water, inner material of tunnel wall, traffic volume, and type of drainage systems. Gravitational separation experiment of SS with collected tunnel wastewater showed considerable removal of pollutants such as 80% of $COD_{Cr}$, 30% of T-N and 90% of T-P simultaneously. GAC isotherm test was conducted to remove dissolved portion of the pollutants, and resulted in high removal efficiencies above 80% of $COD_{Cr}$, T-N, Zn, Cu, Mn, Phenol, CN in the experimental condition of GAC dosage of $50g/1/{\ell}$.