• Environmental Engineering Research
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• v.10 no.6
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• pp.283-293
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• 2005

Characteristics of sulfur-based autotrophic denitrification in a semi-continuous type reactor and the kinetic parameters were studied. Enriched autotrophic denitrifying culture was used for the reactor operation. Biomass growth on sulfur particles and in the liquid medium was monitored using the DAPI staining method. From the result of ion concentration changes and the biomass growth, maximum specific growth rate, ${\mu}_{max}$, and the half velocity constant, $K_M$, were estimated as $0.61\;d^{-1}$ and 3.66 mg/L, respectively. Growth yield coefficient, Y values for electron acceptor and donor were found as 0.49 gVSS/g N and 0.16 gVSS/g S. The biomass showed specific denitrification rate, ranging 0.86-1.13 gN/g VSS-d. A half-order equation was found to best simulate the denitrification process in the packed bed reactor operated in the semi-continuous mode.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.105-110
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• 2021

Objectives: The purpose of this study was to develop a new sterilization plasma device that would be proficient at sterilizing and removing pathogenic bacteria and viruses, and applicable to air purification systems. Methods: In order to understand the performance characteristics, the discharge characteristics of a packed bed DBD reactor and the ozone reduction characteristics of an ozone filter installed at the outlet of the reactor were investigated. Results: The novel packed-bed DBD reactor was proposed, and it was confirmed that the plasma discharge was uniformly and stably discharged throughout the entire layer, and sufficient ozone was generated for sterilization. The ozone filter was tested for three methods: adsorption, adsorption-decomposition, and catalytic decomposition. When the filter thickness was 30 mm, the ozone concentrations were 0.03 ppm, 0.01 ppm, and 0.21 ppm, respectively. The adsorption and adsorption-decomposition methods satisfied the EPA standard of less than 0.05ppm, but the catalytic decomposition method did not. Conclusions: It was confirmed that the adsorption-decomposition method has relatively excellent ozone filter performance and can provide the best ozone filter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.142-149
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• 2008

This paper proposes an effective decomposition method of trichloroethylene using pellet packed-bed non-thermal plasma reactor and catalyst. For that, two types of reactors filled with manganese dioxide and alumina pellets are designed. When $MnO_2$ packed reactor is used, TCE decomposition rate is high due to the generation of oxygen atom radicals at the surface of catalyst during ozone decomposition. In addition, When $Al_2O_3$ packed reactor is used, TCE is oxidized into DCAC and it did not decomposed into small molecules such as COx and $Cl_2$. However, the plasma processed gas using $Al_2O_3$ packed reactor is passed through the $MnO_2$ catalyst reactor, which is placed at the downstream of plasma reactor, the decomposition rate increased as well due to oxygen atom radicals through ozone decomposition. Therefore, the adequate use of $MnO_2$ catalyst in the plasma process is very promising way to increase the decomposition efficiency.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.343-347
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• 2012

The decomposition behaviors of gaseous cyanides in non-thermal plasma-catalyst hybrid reactor have been investigated with the variation of discharge power, influent concentration of cyanide, humidity of air carrier and packed materials in the reactor. Destruction of cyanides by plasma only process was very difficult compared to that of trichloroethylene. But the destruction efficiencies of cyanides were dramatically improved through packing alumina or Pt/alumina bead in the plasma discharge region. From the results, it could be assumed that thermal catalytic effect is involved simultaneously with plasma in the reaction of cyanides destruction on the alumina or Pt/alumina packed plasma reactor.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.75-81
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• 1992

An experimental investigation has been carried out to evaluate the characteristics in wastewater treatment using an anaerobic packed bed bioreactor with ceramics, rubber sponge, soft stone A, and soft stone B as carrier. The results of the work have shown that soft stone A as a carrier was superior to other carriers in methane production, then the content of methane for soft stone A was about 70%. First of all, soft stone A had higher efficiency of the COD removal than the others in response of passing the operation, as well as it had a low volatile acid in reactor. In addition, the slope of methane production with respect to the removal of COD ($m^{3}CH_{4}$/kgCOD) was 0.58 for soft stone A. In biomass hold-up equation for each carriers, the equation of soft stone A was m$_{p}$=714 ($C_{o}/0.41+C_{o}$) and it was the largest in this experimented carriers. Based upon the results obtained, it is suggested that the major effective carrier in wastewater treatments within the packed bed bioreactor used in this experimental work by soft stone A.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.34-40
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• 2000

In the tungsten industry, molybdenum wire which used as the center supporter for coil shape tungsten wire was removed. Nitric acid dissolution method which used prevalently up to the present, takes nitric acid as major component and use noxious material such as sulfuric acid and hydrochloric acid remove molybdenum wire which used as center supporter by dissolve selectively within the range of no damage on tungsten wire. Mixed acid waste water occurred to the process were difficult to be decomposed by the conventional methords. This mixed acid waste water was treated by ozone, and It was obtained using possible by-product through the treatment waste water. For the three reactors with the same volume ; Blank reactor, Disturbance plate reactor, Packed-bed reactor ; the results were as follows : For the blank reactor COD removal efficiency in the pH = 4 (HRT : 6hr) was 28.5%, COD removal efficiency in the pH = 7 (HRT : 6hr) was 28.6%, and COD removal efficiency in the pH = 10 (HRT : 6hr) was 27.8%. For the disturbance plate reactor COD removal efficiency in the pH = 4 (HRT : 6Min.) was 86.5%, COD removal efficiency in the pH =7 (HRT : 6Min.) was 84.4%, and COD removal efficiency in the pH = 10 (HRT : 60Min.) was 86.8%. For the packed-bed reactor COD removal efficiency in the pH = 4 (HRT : 40Min.) was 76.0%, COD removal efficiency in the pH = 7 (HRT : 40Min.) was 81.3%, and COD removal efficiency in the pH = 10 (HRT : 40Min.) was 84.6%. After O3 treatment using possible by-product(Na2SO4) was 150g/ℓ.

• KSBB Journal
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• v.15 no.1
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• pp.88-95
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• 2000

We have produced new-structured oligosaccharides using immoobilized mixed-enzyme reactor of destransucrase from Leuconostoc mesenteroides B-512FMCM and $\alpha$-amylase from Aspergillus oryzae. The reactors of immobilized mixed-exzyme beads were more efficient for the production of oligosaccharides than that of each immobilized enzyme bead in stirred-tank reactior(STR) or in packed-bed reactor(PCR). In continuous flow reactor, the immobilized mixed-enzyme bead in PBR was more stable than in STR, and 52% of initial yield was maintained for 200 hr. New structured-oligosaccharides (NOS) reduced the change of pH in the culture of Streptococcus mutans. It also showed an inhibitory effect on the growth of Staphylococcus aureus.

• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.1-9
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• 1995

This study was carried to investigate the biodegradability of phenol in the wastewater with the two sludge blanket-packed bed reactor in series. Each reactor had a dimension of 0.09 m i.d. and 1.5 m height and consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed of 1 m height. The packed bed region was charged with ceramic raschig rings of 10 mm i.d., 15 mm o.d. and 20 mm length. The reactors were operated at 35$\circ$C and the hydraulic retention time(HRT) was maintained 24 hours. The synthetic wastewater composed of glucose and phenol as major components was fed into the reactor in a continuous mode with incereasing phenol concentration. In addition, the nutrient trace metals($Na^+, Mg^{2+}, Ca^{2+}, PO_4^{3-}, NH_4^+, Co^{2+}, Fe^{2+}$ etc.) were added for growing anaerobes. The phenol concentration of the effluent, the overall gas production, the composition of product gas, the efficiency of COD reduction and the duration of acclimation period were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 2400 mg//l. Successfully stable biodegradation of phenol could be achieved with the anaerobic treatment system from 600 to 1, 800 mg/l of the influent phenol concentration. The upper level of influent phenol loading was high enough to meet most of the practical requirement. The duration of acclimation increased with the phenol loading. At steady state of the influent phenol concentration of 1800 mg/l, the treatment performance indicated the phenol reduction efficiency of 99%, the COD reduction efficiency of 99% and the gas production rate of 37 l/day. At the influent phenol concentration of 2400 mg/l, however, the operation of the treatment system was noted unstable. While the concentration of methane in biogas decreased with increasing the influent phenol loading, the carbon dioxide was increased. However, the concentration of hydrogen was varied negligibly. The concentration of methane was high enough to be used as a fuel. As a result, it is suggested that anaerobic phenol wastewater treament was economical in the sense of energy recovery and wastewater treatment.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.471-472
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• 1999

각종 산업분야에서 발생되는 NO$_{x}$ 및 VOC$_{s}$ 는 발생원에 따라 농도, 조성 및 가스량, 온도등의 조건이 크게 달라, 이를 경제적이고 효율적으로 제어하기 위해서는 각각의 조건 및 처리목적에 따른 적절한 방지기술의 선정이 필요하다.(중략)

• KSBB Journal
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• v.26 no.4
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• pp.328-332
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• 2011

Ethanol production using glycerol as a carbon source was performed by Enterobacter aerogenes immobilized on calcium alginate beads. To improve the ethanol production, the optimal conditions such as loading amount of immobilized cells and glycerol concentration were investigated. The optimal loading amount of immobilized cells and glycerol concentration were 10 mL of calcium alginate bead and 10 g/L, respectively. Consequently, glycerol consumption rate, ethanol concentration and yield were 0.32 g/$L{\cdot}h$, 3.38 g/L and 0.43 g/g on the batch production, respectively. Continuous production of ethanol was successfully achieved using two types of immobilized cell reactors (continuous stirred tank reactor and packed bed reactor) from 10 g/L of glycerol. In the continuous stirred tank reactor, glycerol consumption, ethanol concentration, specific productivity and yield were 9.8 g, 4.67 g/L, 1.17 g/$L{\cdot}h$, 0.48 g/g, respectively. The concentration of produced ethanol was 38-44% higher comparison to batch fermentation, and continuous stirred tank reactor showed better performance than packed bed reactor.