• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.622-629
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• 2014

This study induced biological denitrification and nitrification via a biofiltration process with the view of removing nitrogen from land-based fish farm effluent. To achieve this, we operated an aquaculture nitrogen-removal system that includes a denitrification and nitrification reactor [working volume 40 L, flow rate 64.8 L, HRT (hydraulic retention time) 14.8 h, HRT considering recycling of NOx 7.4 h]. In the continuous process, the nitrification rate of ammonium nitrogen exceeded 90% at a steady state and the denitrification efficiency exceeded 80% with recycling to a pre-anoxic reactor. In addition, the pH in the final effluent was lower with a low influent water alkalinity averaging 100 mg/L (as $CaCO_3$). For effective denitrification reactions, carbon must be supplied via particulate organic matter (POM) hydrolysis because of the low C/N (carbon/nitrogen) ratio in the water.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.468-474
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• 2005

SOx and NOx are known major precursors of acid rain and thus the abatement of their emissions is a major target in air pollution control. To obtain basic data on the removal process of simultaneous $SO_2/NO$, the optimal reaction condition and the composition of reaction solution for simultaneous removal of $SO_2/NO$, ware investigated using a bubble column reactor. Pilot scrubber was consisted of scrubber, filter and control box. Dust removal rate was 83, 92, and 97% with catalyst flux of 0.5, 0.8, 1.5 L/min, respectively Average dust removal efficiency with a kind of nozzle was about 94 and 90% in STS FF6.5 (5/8in.) and 14 of P.P W(1.0in.), respectively Dust and $SO_2$ were removed more than 98-96% regardless of reactor number. In the case of NO gas, removal yield of 83.3% was achieved after 48 hours in 1 stage, also removal yield of 95.7% was reached in 2 stages. In tile case of application of STS (5/8 in.) and P.P (1.0 in.) as used fill packing, removal efficiency was reached higher than 98% without related to of kind of fill packing.

• Nuclear Engineering and Technology
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• v.7 no.4
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• pp.277-284
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• 1975

A result of measurement for the relative dose distribution of neutron gamma mixed radiation field in the biological irradiation facility installed at TRIGA Mark-III reactor is described. The relative dose distributions of neutron-gamma mixed radiation field in the biological exposure room have been experimentally determined using a thermoluminescent dosimeter. Presented herein in graphical forms are the experimental results obtained. It as observed that the region commonly having the characteristics of rather homogeneous horizontal and lateral dose distributions is confined to the area bounded by the two planes horizontally parallel to the beam direction with heights of about 40 cm and 130 cm, respectively, at distances beyond 100 cm from the segmentary surface of the aluminum pool liner projected into the the exposure room, while other areas show a steeper gradient in dosage, especially the places adjacent to the segment of the aluminum pool liner and near the inner po${\gamma}$lion of the concrete walls of the exposure room.

• Journal of Environmental Science International
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• v.28 no.7
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• pp.607-615
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• 2019

The purpose of this study is to biological treatment of high salinity wastewater using Aerobic Granular Sludge (AGS). In laboratory scale's experiments research was performed using a sequencing batch reactor, and evaluation of the denitrification reaction in accordance with the injection condition of salinity concentration, surface properties of microorganisms, and sludge precipitability was performed. The results showed that the salinity concentration increased up to 1.5%, and there was no significant difference in the nitrogen removal efficiency; however, it showed a tendency to decrease gradually from 2.0% onward. The specific denitrification rate (SDNR) was 0.052 - 0.134 mg $NO_3{^-}-N/mg$ MLVSS (mixed liquor volatile suspended solid)${\cdot}day$. The MLVSS/MLSS (mixed liquor suspended solid) ratio decreased to 76.2%, and sludge volume index ($SVI_{30}$) was finally lowered to 57 mL/g. Using an optical microscope, it was also observed that the initial size of the sludge was 0.2 mm, and finally it was formed to 0.8-1.0 mm. Therefore, salinity injection provides favorable conditions for the formation of an AGS, and it was possible to maintain stable granular sludge during long-term operation of the biological treatment system.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.337-346
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• 2005

An MSBR using a membrane for not only filtration but also aeration (MA-MSBR) was designed to reduce membrane fouling and to enhance water quality, and compared with an MSBR using a membrane for only filtration (BA-MSBR). COD removal efficiency of the MA-MSBR was similar to that of the BA-MSBR, but membrane performance of the MA-MSBR was better than that of the BA-MSBR. The MA-MSBR had more small particles in mixed liquor, so the specific cake resistance of flocs in the MA-MSBR was higher than that in the BA-MSBR. However, in the aerobic reaction step of the MA-MSBR, air went through membrane pores and out of the membrane surface, so cake layers on the membrane surface and a portion of organics adsorbed on membrane pores could be removed periodically. Therefore, cake resistance, $R_c$, and fouling resistance by adsorption and blocking, $R_f$, for the MA-MSBR increased more slowly than those for the BA-MSBR. Additionally, in order to compare the energy efficiency for two MSBRs, oxygen transfer efficiency and power to supply air into the reactor by a membrane module and a bubble stone diffuser were measured using deionized water. From these measurements, the transferred oxygen amount per unit energy was calculated, resulting that of MA-MSBR was slightly higher than that of BA-MSBR.

• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.1-6
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• 2013

This study was focused on improving nitrification efficiencies of M-dephanox (Modified-Dephanox) process. Rotating biological contactor (RBC) was used instead of floating sponge type media in nitrification reactor. High ammonia removal efficiencies were observed in nitrification reactor, regardless of organic loading from contactor of M-dephanox process. Denitrification efficiencies were also increased to maintain low $NO_3-N$ concentration in effluent. This enhanced phosphate release in anaerobic contactor and resulted in high removal efficiencies of phophorus. Average removal efficiencies of $TCOD_{Cr}$ and $SCOD_{Cr}$ were 93.8% and 81.6%, respectively, while those of TKN and ${NH_4}^+-N$ were 80.9% and 74.4%, respectively. As for phosphorous treatment, the average removal efficiencies of TP and OP were 94.7% and 94.3%, respectively. Also, effect of operating temperature on nitrogen removal was examined. Average removal efficiency of TN was 65.8 % at $15^{\circ}C$ or below (at average temperature of $13.3^{\circ}C$), while that was 82.8% at $15^{\circ}C$ or above (at average temperature of $21.9^{\circ}C$).

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.273-278
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• 1985

A carrier-supported mycelial growth of Penicillium chrysogenum was applied to penicillin fermentation system. Among various materials tested, celite was found to be most effective for both spore adsorption and bioparticle development. Hyphal growth through pore matrices of the material showed strong anchorages and provided highly stable biofilm growths. When 5-10％ celite was employed, both cell growth and penicillin production were observed to increase significantly comparing to the dispersed filamentous growth. Specific productivity of penicillin, however. was found to be kept almost constant at a value of 1,900 unit/g cell/hr. A semicontinuous fermentation in a fluidized-bed reactor. using the tarrier-supported biofilm growth, was conducted successfully although free mycelia appeared in the late phase of the fermentation made the reactor operation difficult. Control of the size of bioparticles was considered as a major operating factor to maintain the reactor productivity at a desired level.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.86-92
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• 1995

This study was performed to evaluate the effect of temperature on operating parameters for reactor in pig wastewater treatment using sequencing batch reactor method which is one of the biological treatment methods. Study was accomplished by experimental apparatus of bench scale, and the degradation rate coefficient and temperature correction factor were derived. The followings are the conclusions that were derived from this study. 1. In the characteristics of pig wastewater, concentrations of TKN and T-P were very high as 590 mg/l and 40 mg/l, respectively. 2. Removal efficiency of BOD and $COD_{Mn}$ as organic compound indicators were the highest mark as 97% at 25$\circ$C. 3. When temperature was incresed from 10$\circ$C to 25$\circ$C, removal efficiencies of TKN and T-P were proportionally increased. Especially, the former was greatly effected by temperature of reactor. 4. In experiment of bench scale, the degradation rate coefficients were increased as temperature increased, but decreased at the temperature range of 25~35$\circ$C. Temperature adjustment coefficients for $COD_{Mn}$, BOD, TKN and T-P were 1.1460, 1.1356, 1.1140 and 1.0565, respectively.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.25-33
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• 1996

This study was conducted to Investigate the biological treatment capability of MMCMAS(Movinig Media Complete Mixing Activated Sludge) reactor for high strength organic wastewater (Average BOD=800mg/l). And this experimental results were compared previous study for low strength organic wastewater (Average HOD=150mg/l) by the same reactor. In this study, we abtained following conclusions ; (1) The laboratory MMCMAS reactor demonstrated that SBOD removal efficiencies of more than 90% can be achieved at organic Bonding rates of 30.9 gBOD/$m^2$/d for high strength organic wastewater and 39.4 gBOD/$m^2$/d for low strength organic wastewater, respectively. (2) The nitrification rates of MMCMAS reactor was found same results of similiar organic loading rates. (3) The ratio of attached biomass to total biomass on the moving media varied in the range of 40 to 63% and 32 to 94% for high and low strength organic wastewater, respectively. And it was varied at the various concentration of influents for the similiar organic loading rates. The sludge production rates was found approximately 0.37 gVSS/$gBOD_{rem}$. in MMCMAS reactor.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2321-2326
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• 2018

We evaluated the optimal conditions for fluidization of nickel oxide (NiO) and its reduction into high-purity Ni during hydrogen reduction in a laboratory-scale fluidized bed reactor. A comparative study was performed through structural shape analysis using scanning electron microscopy (SEM); variance in pressure drop, minimum fluidization velocity, terminal velocity, reduction rate, and mass loss were assessed at temperatures ranging from 400 to $600^{\circ}C$ and at 20, 40, and 60 min in reaction time. We estimated the sample weight with most active fluidization to be 200 g based on the bed diameter of the fluidized bed reactor and height of the stocked material. The optimal conditions for NiO hydrogen reduction were found to be height of sample H to the internal fluidized bed reactor diameter D was H/D=1, reaction temperature of $550^{\circ}C$, reaction time of 60 min, superficial gas velocity of 0.011 m/s, and pressure drop of 77 Pa during fluidization. We determined the best operating conditions for the NiO hydrogen reduction process based on these findings.