• Journal of Soil and Groundwater Environment
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• v.11 no.4
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• pp.10-17
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• 2006

Laboratory-scale two-dimensional aquifer physical model studies were conducted to assess the effect of air injection rate and air injection pattern on the removal of disel contaminated soil and groundwater by air/bio-sparging. The experimental results were represented that the optimal conditions in this experiment were as air injection rate of 1,000 ml/min and pulsed air injection pattern(15 min on/off). The results of the TPH reduction, DO consumption and $CO_2$ production indicate the effective biodegradation evidence of diesel. Based on our results, The minimal $O_2$ supply and pulsed air injection pattern could effectively enhance the diesel removal and the pulsing air injection had effect on oxygenation in this system. Thus, the cost of operating air/bio-sparging system will be reduced if optimal air injection rate and pulsed air injection pattern are applied to remediate contaminants.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.1
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• pp.104-109
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• 2004

In this study, we stabilized the screened soil from landfills by using aerobic bioreactor and evaluated aerobic decomposition of it. Four lab-scale bioreactors (anaerobic and 1 PV/day aeration, 5 PV/day aeration, 10 PV/day aeration) filled with screened soil were operated to investigate the effect of air injection quantity on stabilization of screened soil. In case of aerobic bioreactors, the decomposition of organics in screened soil was higher than anaerobic bioreactor. According to the results of landfill gas and soil respiration test, the air injection quantity of 5 PV/day was most efficient in stabilization of screened soil.

• Resources Recycling
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• v.27 no.1
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• pp.45-54
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• 2018

This study aimed to investigate the effects of mechanical factors such as agitation speed and air rate in fly ash flotation. Specifically, we used thermal power plant fly ash with unburned carbon content of 3.4 to 3.7%. The effect of pH, agitation speed, collector dosage, and frother dosage - the key factors of froth flotation - showed unburned carbon recovery and unburned carbon content of 63% and 34%, respectively, when the dosage of safflower oil used as collector was 800 g/ton, pH was 7, agitation speed was 1,200 rpm, and frother dosage was 400 g/ton. The SEM/EDS analysis of fly ash in that case indicated that the spherical fly ash particles lowered the unburned carbon content as they floated with the air bubbles without being dissolved in the unburned carbon or settled in the ore solution. The other experiment of changing the mechanical factors such as agitation speed and air rate resulted in unburned carbon recovery and unburned carbon content of 74% and 67%, respectively, at air rate of 8 L/min and agitation speed of 900 rpm. The recovery and unburned carbon content increased as the low agitation speed and additional air injection decreased the strength of the eddy current in the ore solution and consequently prevented the floating of fine fly ash particles with unburned carbon. In addition, the recovery rate and unburned carbon increased further to 80% and 70%, respectively, showing the best performance when the agitation speed and air rate were lowered to 800 rpm and 6 L/min, respectively.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.11a
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• pp.42-45
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• 1993

내경 0.1 m 의 draft tube 를 갖는 직경 0.3 m, 높이 2.7 m 인 내부순환유동층 가스화반응기에서 호주산 준 역청탄을 공기와 수증기를 사용하여 가스화 하였다. draft tube에 공기를 주입하여 연소반응, annulus 구역에 수증기를 주입하여 가스화하여 연소반응에서 생성된 열을 annulus 에 공급하였다. 반응기온도와 석탄주입량에 따라 H$_2$, CO 및 발열량이 증가하였으나 공기의 유량증가에 따른 H$_2$, CO는 감소하고 $CO_2$ 는 증가하였으며 발열량은 감소하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.191-194
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• 2002

토양증기추출(Soil Vapor Extraction)법을 이용하여 대표적 휘발성 NAPL (Non-aqueous phase liquid)인 TCE (trichloroethylene)와 toluene을 토양으로부터 제거하는 칼럼 실험을 실시하였다. 토양특성 및 증기추출 조건들이 정화효율에 미치는 영향을 규명하는데, 균질한 Ottawa sand와 실제 오염지역의 토양들을 직경 2.5cm, 길이 30cm인 유리 칼럼이 충진시켰으며, 빨갛게 염색된 TCE 또는 toluene 4 g이 주입되었다 공기 유량계를 설치하여 0.03L/min의 일정한 속도로 공기가 주입되도록 하고, 퍼지장치를 설치하여 주입 공기의 습윤도를 99% 이상으로 유지하였다. 가스크로마토그래피로 유출 가스 농도를 분석하였다. Ottawa sand로 충진된 칼럼실험에서는 매질의 입자크기, 함수율, 토양 내 오염물 체류시간 등을 변화시켜 실험을 반복하였다. TCE로 오염된 세립질 Ottawa sand 칼럼실험에서 유출 공기의 최대 농도는 조립질 Ottawa sand 칼럼의 유출 농도보다 약 20% 정도 감소하였고, 오염지역의 실제토양 칼럼실험에서는 최대유출농도가 조립질 Ottawa sand 칼럼의 농도보다 약 50% 감소하였으나, 20 liter공기 주입 후부터는 모두 비슷한 농도감소 현상을 나타내었으며, 초기 주입량의 90 % 이상이 제거되었다. 함수율증가에 따른 유출공기의 농도 감소는 거의 나타나지 않았으며, TCE 주입 후 7일 동안 방치하였다가 SVE를 실시한 칼럼 실험에서도 잔류하는 TCE의 양이 약간 증가하였지만 20 liter 공기 추출 후에는 초기 주입량의 90% 가, 40 liter공기 추출 후에는 98% 이상이 제거되었다. Toluene으로 오염된 칼럼 실험에서도 TCE와 비슷한 제거 경향을 나타냈으며 200 liter 공기 추출 후에는 오염물 초기 주입량의 98% 이상이 제거되었다. 본 실험 결과로부터 증기추출법을 이용한 TCE, toluene 정화 효율성이 규명되었으며, 휘발성 NAPL로 오염된 실제 토양을 복원하기 위한 SVE법의 적용가능성을 확인할 수 있었다.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.101-101
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• 2003

본 연구는 남은 음식물을 유산균을 이용하여 발효 사료화 하기 위해 실시하였다. 발효를 촉진시키기 위한 균주로는 Lactobacillus acidophilus를 사용하였고 최적의 발효조건을 갖는 공기 주입량을 알아보기 위해 시료의 발효 조건을 각각 달리 하였다. 시료는 교반하지 않고 공기주입 또한 없는 혐기적 조건의 것과 50rpm의 속도로 교반하면서 0.25v.v.m의 공기를 주입한군, 70rpm의 속도로 교반하면서 0.5v.v.m의 공기를 주입한 군으로 나누었다. 시료는 모두 $37^{\circ}C$로 유지하면서 48시간 발효 시키며 12시간 단위로 시료를 채취하였다. p.H와 유기산함량, 환원당함량과 유산균수를 측정하여 남은 음식물을 발효시키기 위한 최적의 공기 주입량을 알아보았다. 실험결과 50rpm 0.25v.v.m에서 가장 낮은 p.H를 보여주었고 유기산 함량과 환원당 함량은 70rpm 0.5v.v.m에서 가장 높은 함량을 보였다. 유산균은 50rpm 0.25v.v.m에서 가장 많은 증식되었음을 보여주어 적절한 공기의 주입이 남은 음식물의 발효를 촉진하는 것으로 보여진다.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.46-53
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• 2018

This study was conducted to determine which greenhouse provided good environmental conditions for strawberry production, and performed better at conserving energy. Temperature, RH, VPD, $CO_2$, solar radiation, yield, and fuel consumption were the parameters analyzed. The temperatures of both greenhouses were well controlled in order to provide optimal day and night temperatures for strawberry production. The air inflated double layer greenhouse had higher RH values (more than 90% at night), which led to higher disease occurrence, in comparison to the conventional double layer greenhouse. Furthermore, the air inflated double layer greenhouse had lower VPD values than the conventional double layer greenhouse. Therefore, better RH and VPD were observed in the conventional double layer greenhouse. Higher $CO_2$ concentration was observed in the air inflated double layer greenhouse while the conventional double layer greenhouse ventilated better than the air inflated greenhouse, because of its side ventilators. Moreover, higher solar radiation in the conventional double layer greenhouse resulted in higher yield, in comparison to the air inflated double layer greenhouse. Thus, we can conclude that the conventional double layer greenhouse provided a better environment for crop growth, in comparison to the air inflated double layer greenhouse. Regarding fuel consumption, the air inflated double layer greenhouse had lower fuel consumption than the conventional double layer greenhouse. Therefore, from an energy consumption point of view, we can conclude that the air inflated double layer greenhouse performed better than the conventional double layer greenhouse.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.338-341
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• 2006

본 연구에서는 지하수내 TCE 농도가 높은 2개 지역을 선정하여 3회에 걸쳐 공기탈기법 시험을 실시하였다. 2개 지역의 지하수내 TCE 배경 농도는 각각 0.360, 0.317 mg/L이며 반응조에 주입된 공기는 각각 17.14, 44.78, 76.51 L/min의 비율로 주입하였다. 또한 반응조에서 배출되는 기체내의 TCE의 농도를 측정하기위해 PID(photo-ionization detector)를 장착하여 측정하였다. PID를 이용하여 배출되는 기체를 측정한 결과, TCE 농도는 $6{\sim}8$분만에 최고 농도로 배출되었고 시간이 지날수록 천천히 감소하는 형태를 나타내었다. 반응조내의 TCE 농도 변화는 공기 유입 속도에 따라 매우 큰 변화를 나타내었다. TCE가 17.14 L/min의 공기유입속도에서 160분 동안 64%, 44.78 L/min에서 135분 동안 93%, 76.51 L/min에서 120분 동안 95.3%가 제거되었다. 따라서 TCE를 제거하기 위한 DAS 기법은 공기의 주입비율에 따라 제거 속도의 큰 변화를 보였다.

• Membrane Journal
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• v.27 no.1
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• pp.43-52
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• 2017

The air injection nozzle tube was inserted inside of the tubular membrane module to reduce membrane fouling and improve the permeate flux. The average pore size of membrane was $0.1\;{\mu}m$ and the yeast was used as a foulant. All of permeate experiments were started without air injection for the module equipped with the nozzle tube, then carried out continuously with air injection. Finally, the nozzle tube was removed from the module and the permeate was measured without air injection. The measured permeate fluxes were compared to examine the effect of air injection. The fluxes for air injection were consistently maintained or increased. The fluxes of no-air injection with the nozzle tube were greater than those of the empty tubular module. As operating pressure decreased to 0.4 bar, the flux enhancement of air injection based on no-nozzle case increased to 21%. Flux enhancements of air injection were above 30% as the gas/liquid two-phase flow was changed from the stratified-smooth to the intermittent pattern due to increase of gas flowrate.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.432-436
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• 2012

This study was conducted to determine the optimal aeration rate for mass propagation of ever-bearing strawberry by bioreactor culture. The aeration rate was treated in four levels: 0.1 vvm (air volume/medium volume/min), 0.2 vvm, 0.3 vvm, and 0.4 vvm. In 0.2 vvm conditions, shoot length was the longest at 9.03 cm in bioreactor culture, leave numbers were 40.4 ea and fresh weight was 6,106 mg. Plant growth rate at 0.2 vvm condition was faster than other treatments. In the aeration condition, 0.2 vvm was most effective to increase aerial part growth and to decrease medium consumption. As the culture periods increased, the fresh weight also increased rapidly. After six weeks of cultivation, shoots were emerged with 10.4 ea per plantlet, resulting in developing a complete plant. As a result, the bioreactor culture system for mass propagation of strawberry is required to continuously supply the air by 0.2 vvm speed and cultivate at least for six weeks.