• Journal of Animal Environmental Science
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• v.16 no.3
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• pp.167-174
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• 2010

This study was performed to evaluate the removal effects of nutritive salts and organic pollutants in experimental aeration reactor for treatment of piggery slurry. In this study, three types of reactors were manufactured and operated. The fibrous media was equipped in one of three reactors. Another reactor was equipped with the siliceous media and the other reactor used as a control was equipped with typical aeration system only. Treatment efficacy of three types of reactors were evaluated according to the pollutants removal rate of the piggery slurry. The results obtained in this study are as follows : 1) In the reactor containing fibrous media, the removal efficiency of BOD, T-N and T-P was 11%, 13.9% and 21.2%, respectively. 2) In the reactor containing siliceous media, the removal efficiency of BOD, T-N and T-P was 6.9%, 25.3% and 47.8%, respectively. 3) In the reactor not containing media, the removal efficiency of BOD. T-N and T-P was 6.1%, 8.1.% and 23.6%, respectively. 4) Sludge accumulation in the reactor equipped with filamentous media was lower than that of other experimental reactors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.251-259
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• 2016

This study examined the DO concentration distribution and ORP distribution using microbubbles on pilot-scale aeration tanks. As a result of MLSS mixing and oxygen transfer phenomenon using microbubbles, different DO concentrations were observed depending on the circulation of the liquid with the microbubble supply location on the lateral of an aeration tank. The simulation results of CFD (computational fluid dynamics) program showed that MLSS mixed with a microbubble supply in the middle the reactor is much better than on the left side of the reactor. A single reactor containing an anaerobic, anoxic, and aerobic zone, was evaluated without partition according to the location of the microbubble supply based on the experiments and CFD analysis. MLSS was separated into solid-liquid by the microbubble supply in the aeration tank. Consequently, selecting the appropriate microbubble size is important for MLSS mixing and was maintained at the proper DO concentration for biological treatment.

• Resources Recycling
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• v.28 no.6
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• pp.73-78
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• 2019

In this investigation, off-gas generated from the activated sludge in wastewater treatment plant was monitored. Through monitoring, the oxygen transfer efficiency in the aeration system and the reliability was evaluated by comparing to clean water. First, the dissolved oxygen, oxygen transfer coefficient, and standard oxygen transfer efficiency were measured based on clean water, and the values were 8.60 mg/L, 9.490/hr and 23.96%, respectively. The off-gas monitoring at the wastewater treatment plant indicated that the standard oxygen transfer efficiency was 22.81%. Little difference in oxygen transfer efficiency this data inferred that the performance was improved through diffuser installation in the field monitoring system.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.301-305
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• 1998

This study was conducted to evaluate the liquid composting efficiency using pig manure in different condition such as simple storage type reactor, continuous aeration reactor, anaerobic reactor and anaerobic agitation reactor. Continuous aeration reactor was the most efficiency method to BOD and malodors removal than other methods. While nitrogen loss in continuous aeration reactor was 47% of initial concentration, which was the higher amount than any other digestion methods. The digestion efficiency between anaerobic reactor and anaerobic agitation reactor were similar, but E. coli and malodor removal efficiency were a little higher in the anaerobic agitation reactor. Simple storage type reactor which was conventional digestion method in rural area gave lower efficiency than aerobic and anaerobic digestion methods in view of BOD, E. coli and malodor removal. The liquid composting efficiency which were evaluated by various indicators like pH, BOD, E, coli, malodor and nitrogen loss was high in the order of anaerobic agitation reactor>continuous aeration reactor>anaerobic reactor>simple storage type reactor.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.1945-1954
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• 2000

This study provides economical installation capacities for wastewater reclamation and reusing system in 7 areas of South Korea applying to contact aeration process using NPV(net present value) model based on cost-benefit. First. considering only private benefits. economical installation capacities for wastewater reclamation and reusing system applying to contact aeration process in household use were more than $500m^3/day$ in Pusan. $1,000m^3/day$ in Taegu. $2,000m^3/day$ in Kwangju. However. installation capacities in Seoul. Inchen, Taejon, and Ulsan were not optimal for $3,000m^3/day$. Therefore, supply ways of wastewater reclamation and reusing system in household use in the latter areas were more optimal local recirculation system than individual recirculation system. Economical installation capacities for wastewater reclamation and reusing system in business use were more than $100m^3/day$ in Seoul. Pusan. and Kwangju and which were $300m^3/day$ in Taegu, Inchen, Taejon, and Ulsan. Economical installation capacities for wastewater reclamation and reusing system in commercial use were more than $100m^3/day$ in Seoul, Pusan, Taegu, Kwangju, Taejon, and Ulsan, and which were $300m^3/day$ in Inchen. Second, considering only social benefits. economical installation capacity for wastewater reclamation and reusing system applying to contact aeration process was more than $100m^3/day$.

• Korean Journal of Optics and Photonics
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• v.20 no.5
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• pp.261-265
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• 2009

Our amplifier using an all optical method and a fixed GFF achieved automatic gain flatness throughput the C-band without any NF degradation, and simultaneously achieved a constant 25 dB gain, while input signals were varied between one channel and forty WDM channels. When thirty nine channels were added and dropped, the transient gain variation of the survival channel was not greater than the steady-state gain variation, and its wavelength dependency was negligible.

• Water for future
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• v.19 no.4
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• pp.321-328
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• 1986

Bottom sediment-river water samples were studied to determine the extent of biodegradable matter and to examine the reduction of COD, TKN and TOC by using of warburg and aerated batch reactor. Warburg studies were conducted to study the Oxygen Uptake Rates, Reaction Rate Constants and CBOD. Bacth reator studies were conducted to determine the reduction of COD, TKN and TOC. Results from the batch recator study indicate high concentration of COD in samples. Less than 10 precent of the Organic Carbon was found to be biodegradable in 48 hours of Warburg experiment. Appreciable Immediate Oxygen Demand of sediments suggests that dredging of the river bottom is likely to deplete dissolved significantly in the river water.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.3
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• pp.5-16
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• 2021

In this study, the applicability of the MBR(Membrane Bio Reactor) process of oxygen dissolve was evaluated through comparison and evaluation of the efficiency of oxygen dissolve device and conventional aeration device in the explosive tank within the MBR process. The organic matter and ammonia oxidation by oxygen dissolve device were evaluated, and the efficiency of persaturation was evaluated by applying real waste water (anaerobic digester effluent treatement from food waste). SCOD and ammonia removal rates for oxygen dissolve device and conventional aeration device methods were similar. However, it was determined that the excess sludge treatment cost could be reduced as the yield of microorganisms by oxygen dissolve device is about 0.03 g MLSS-produced/g SCOD-removed lower than that of microorganisms by conventional aeration device. The removal rates of high concentrations of organic matter (4,000 mg/L) and ammonia (1,400 mg/L) in anaerobic digester effluent treatment from food waste were compared to the conventional aeration device and the oxygen dissolve device organic matter removal rate was approximately 13% higher than that of the conventional aeration device. In addition, for MLSS, the conventional aeration device was 0.3 times higher than for oxygen dissolve device. This is believed to be due to the high progress of sludge autooxidation because the dissolved oxygen is sufficiently maintained and supplied in the explosive tank for oxygen dissolve device. Therefore, it was determined that the use of oxygen dissolve device will be more economical than conventional aeration device as a way to treat wastewater containing high concentrations of organic matter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.190-195
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• 2000

This paper presents the fabrication of the LNA which is operating at 2.13∼2.16 GHz for IMT-2000 lot-end receiver using series feedback and resistive decoupling circuit. Series feedback added to the source lead of a transistor keep the low noise characteristics and drop the input reflection coefficient of amplifier simultaneously. Also, it increases the stability of the LNA. Resistive decoupling circuit is suitable for input stage matching because a signal at low frequency is dissipated by a resistor in the matching network The amplifier consist of GaAs FET ATF-10136 for low noise stage and VNA-25 which is internally matched MMIC for high gain stage. The amplifier is fabricated with both the RF circuits and self bias circuit on the Teflon substrate with 3.5 permittivity. The measured results of the LNA which is fabricated using above design technique are presented more than 30 dB in gain P$\_$ldB/ 17 dB and less than 0.7 dB in noise figure, 1.5 in input$.$output SWR(Standing Wave Ratio).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.8-14
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• 2000

This paper analyzes and accesses the gain of optically pumped surface-normal MQW optical amplifiers. The proposed amplifiers have the advantage of polarization independence, high coupling efficiency to and from optical fibers, and flexibility of operating wavelength. We analyzed the gain characteristics of 100 - 200-period MQWs and verified the dependence of a strained lattice and selective doping. Theoretical analysis of such MQWs showsa single-pass gain of 3 dB with broad operation bandwidth. A single-pass gain of 2.6 dB is obtained experimentally in an InGaAs/InGaAlAs MQW amplifier, which is compared with calculations. The use of Fabry-Perot interferometer (FPI) structure in an optical amplifier is a useful way to increase the gain, but causes a problem of narrow operation bandwidth when the single-pass gain is low. Therefore, a single-pass gain above 2to 3 dB is a prerequisite to achieve both a high gain and moderate operation bandwidth in FPI-structured opticalamplifiers. We have designed an FPI-structured surface-normal optical amplifier both with a high gain of broad operation bandwidth of 4.6mm, when a single-pass gain is 3 dB.