• Title, Summary, Keyword: Aeration

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Nutrients removal on Oxic/Anoxic time ratio in 2-stage-intermittent-aeration reactor (2단 간헐 포기조의 포기/비포기 시간비에 따른 영양염류 제거특성)

  • Kim, Hong Tae;Sin, Seok U;O, Sang Hwa;Gwon, Seong Hyeon
    • Journal of Environmental Science International
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    • v.13 no.7
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    • pp.675-680
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    • 2004
  • This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P, and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

Effect of aeration process on changes of prosapogenin content and antioxidant activity of red ginseng powder extract (Aeration 공정 처리가 홍삼분말 추출물의 프로사포게닌의 함량 변화와 항산화 활성에 미치는 영향)

  • Ryu, Hee-Jeong;Jung, Chul-Jong;Seo, Jeong-Gyun;Li, Xian;Yu, Yeong-Eun;Beik, Gyung-Yun
    • Korean Journal of Food Science and Technology
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    • v.51 no.6
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    • pp.576-583
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    • 2019
  • The effect of aeration process in causing changes in the prosapogenin content and the antioxidant activity of red ginseng powder extracts was investigated. With respect to the color change of the extracts, the L-value and b-value decreased significantly with the lapse of extraction time both with and without the aeration process. The a-value increased with the lapse of the extraction time in the non-aeration process but decreased in the aeration process. This result suggests that when the aeration process was performed, the lightness, yellowness, and redness decreased with the lapse of the extraction time, resulting in a darker color. The total polyphenolic and total flavonoid contents were the highest at 0.84 and 0.96 mg Gallic Acid Equivalent (GAE)/mL, 21.77 and 21.93 mg GAE/mL at 24 h and 36 h, respectively for the aerated red ginseng powder extracts. The DPPH, ABTS, H2O2 scavenging activity, and reducing power were measured to confirm the antioxidant effects of red ginseng powder extracts after the aeration process. Thus, the antioxidant activity was increased in the aerated red ginseng powder extracts. In addition, when comparing the contents of Rb1, Rg1, and Rg3, the content of Rg3 was significantly different, and it was confirmed that a large amount was produced in the aerated red ginseng extracts. These results indicate that the red ginseng extracts subjected to the aeration process are superior than the ones processed by the non-aeration process.

Influence of Aeration Cycle on Nitrogen and Phosphorus Removal in Two-Stage Intermittent Aeration System (2단 간헐폭기 시스템에서 aeration cycle이 질소 및 인 제거에 미치는 영향)

  • Jeong, Myoung-Sun;Lee, Jun-Ho;Seo, Kwang-Bum;Kim, Yeong-Kwan
    • Journal of Industrial Technology
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    • v.23 no.A
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    • pp.193-197
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    • 2003
  • This bench-scale research investigated the aeration cycle(on/off) as the controlling factors for nitrogen and phosphorus removal in a 2-stage, intermittent aeration process. At this experiment, the aeration cycle time(air-on/air-off) was 30min/30min, 60min/60min, 90min/90min. Organic matter removal was observed more than 90% regardless of the aeration cycle and phosphorus removal was relatively high when the aeration cycle time was 60min/60min On the other hand. For all of the aeration cycle, TN removal was appeared less than 55%. This result was probably due to the limitation of the external substrate for heterotrophic nitrification and aerobic denitrification.

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A Study on the Aeration Mechanism in the Engine Lubrication System (엔진 윤활 시스템에 있어서 Aeration 발생 Mechanism연구)

  • 윤정의;전문수
    • Tribology and Lubricants
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    • v.17 no.6
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    • pp.447-452
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    • 2001
  • In development process of engine lubrication system, many failure cases are related with aeration problem. Therefore, it is very important to clarify the aeration in the engine oil circuit system. As of today, many factors have been introduced as the major cause in the engine oil aeration. However, still many test data related with those are required to clearly understand it. In this paper the aeration measurement system and calculation method are introduced. And also using this system we measured engine oil aeration for various cases. From these results some conclusions are reduced.

Aeration Control of Thermophilic Aerobic Digestion Using Fluorescence Monitoring

  • Kim, Young-Kee;Oh, Byung-Keun
    • Journal of Microbiology and Biotechnology
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    • v.19 no.1
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    • pp.93-98
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    • 2009
  • The thermophilic aerobic digestion (TAD) process is recognized as an effective method for rapid waste activated sludge (WAS) degradation and the deactivation of pathogenic microorganisms. Yet, high energy costs due to heating and aeration have limited the commercialization of economical TAD processes. Previous research on autothermal thermophilic aerobic digestion (ATAD) has already reduced the heating cost. However, only a few studies have focused on reducing the aeration cost. Therefore, this study applied a two-step aeration control strategy to a fill-and-draw mode semicontinuous TAD process. The NADH-dependent fluorescence was monitored throughout the TAD experiment, and the aeration rate shifted according to the fluorescence intensity. As a result, the simple two-step aeration control operation achieved a 20.3% reduction in the total aeration, while maintaining an effective and stable operation. It is also expected that more savings can be achieved with a further reduction of the lower aeration rate or multisegmentation of the aeration rate.

A Study on the Mechanism of Oil Aeration in Automotive Engines(I) (엔진 오일의 공기 혼입 발생기구에 관한 연구(I))

  • 이두순;김원규;오대윤;최재권
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.7
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    • pp.129-135
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    • 1999
  • We developed a new measuring equipment which makes it possible to perform on-line measurements with the merits of its implicity and the time-saving characteristics. By using the newly developed measurement system, the amount of aeration is directly measured on several parameters, i.e, engine speed, oil quantity, oil deterioration, oil temperature and viscosity, etc. It showed that oil aeration is strongly related to be gas movements in crankcase and the residence time of circulating oil in oil pan. In addition, in order to clarify the mechanism of aeration and to quantify the degree of aeration, a modelling analysis to predict aeration was performed , and as a guiding parameter, Aeration Index was defined. Finally, the parameter was compared with the actual amount of aeration, and it was confirmed that they gave a good correlation with each other.

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Evaluation of Operation Characteristics with Aeration Time in Intermittent Aeration Membrane Bioreactor (간헐포기 MBR공정에서 포기시간에 따른 운전특성 평가)

  • Lim, Bong-Su;Choi, Bong-Cheol
    • Journal of Korean Society on Water Environment
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    • v.21 no.4
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    • pp.353-359
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    • 2005
  • This study was conducted to evaluate the operation characteristics with aeration time in intermittent aeration membrane bioreactor. The BOD removal efficiency rate of this process was over than 97% regardless of aeration on/off time. To get over than 82% of nitrogen removal efficiency rate, aeration off time needs more than 70 minutes in reactor. Specific denitrfication rate was 2.68 mg $NO_3-N/gMv/hr$ in 40/80 min aeration on/off time, was 2.6 times more than 60/60 min, and 1.4 times more than 50/70 min in 6,300 mg/L of MLSS concentration. Specific nitrification rate was 1.96 mg $NH_4-N/gMv/hr$ in 50/70 min, was 1.4 times more than 40/80 min, but it was effectded little upon nitrification. Microbial activity was effected little according to aeration on/off time, oxygen demend was reduced according to aeration off time increased and microbial concentration increased. The longer aeration off time become, the higher Extraceller Pollymeric Substance (EPS), 50/70 min and 40/80 min in aeration on/off time was increased 1.6 times and 2.7 times, respectively more than 60/60 min because of increase of operation pressure.

Effects of Pre-aeration on the Anaerobic Digestion of Sewage Sludge

  • Ahn, Young-Mi;Wi, Jun;Park, Jin-Kyu;Higuchi, Sotaro;Lee, Nam-Hoon
    • Environmental Engineering Research
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    • v.19 no.1
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    • pp.59-66
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    • 2014
  • The aim of this study was to assess the effect of pre-aeration on sludge solubilization and the behaviors of nitrogen, dissolved sulfide, sulfate, and siloxane. The results of this study showed that soluble chemical oxygen demand in sewage sludge could be increased through pre-aeration. The pre-aeration process resulted in a higher methane yield compared to the anaerobic condition (blank). The pre-aeration of sewage sludge, therefore, was shown to be an effective method for enhancing the digestibility of the sewage sludge. In addition, this result confirms that the pre-aeration of sewage sludge prior to its anaerobic digestion accelerates the growth of methanogenic bacteria. Removal rates for $NH_3$-N and T-N increased simultaneously during pre-aeration, indicating simultaneous nitrification and denitrification. The siloxane concentration in sewage sludge decreased by 40% after 96 hr of pre-aeration; in contrast, the sulfide concentration in sewage sludge did not change. Therefore, pre-aeration can be employed as an efficient treatment option to achieve higher methane yield and lower siloxane concentration in sewage sludge. In addition, reduction of nitrogen loading by pre-aeration can reduce operating costs to achieve better effluent water quality in wastewater treatment plant and benefit the anaerobic process by minimizing the toxic effect of ammonia.

A Study on the Engine Friction & Lubrication Characteristics related with Oil Aeration (오일 Aeration에 따른 엔진의 마찰 및 윤활 특성에 대한 연구)

  • 김영직;이창희;윤정의
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.184-189
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    • 1999
  • This Paper presents the friction and lubrication charateristic related with oil aeration. It is well known that oil aeration occurs severe problem on lubrication system, in particular, in the engine bearings and hydraulic lash adjuster. In this study, engine tests were carried out in motoring conditions. In order to investigate oil aeration characteristics, we measured oil aeration with respect to oil temperature, oil viscosity, modified oil drain system. From the results, we concluded that aeration can be reduced by improving oil drain system and FMEP can be reduced by minimising of aeration.

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A Study of Substrate Removal in Wastewater Flow Variations by Submerged Biofilm Reactor (浸漬型 生物膜反應槽에 의한 負荷變動에서의 基質除去에 관한 연구)

  • Nam, Chul-Hyun;Park, Jong-Woong
    • Journal of Environmental Health Sciences
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    • v.13 no.2
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    • pp.83-90
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    • 1987
  • The objective of this study is to review the basic theories related substrate removal in wastewater flow variations using submerged biofilm reactor. An aerated biofilm reactor is that in which influent organic substrates are aerobically oxidized by the microorganisms of biofilm grown on the surface of submerged media. No sludge is returned, and oxygen is supplied by diffusers. Three types of aerated biofilm reactor are one stage-central aeration, one stageup flow aeration and two stage-side aeration. The orders of substrate removal capacity in wastewater flow variations showed two stage-side aeration, one stage-upflow aeration and one stage-central aeration. The phenonmenon of nonclosing volid in upflow aeration type was superior to these in central-side aeration type. Attached biofilm masses in case of upflow, side and central aeration reactor were 1.0mg/cm$^2$, 4.1 mg/cm$^2$ and 0.93 mg/cm$^2$, respectively. Yield coefficient for biofilm was 0.31 to 0.48. Especially, removal efficiency can be increased remarkably according to the number of biofilm reactor and the packed condition of media.

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