• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1001-1009
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• 2000

This study is to find the utilization of intermittent aeration system, around S-COD, T-COD, SS, timewise changes of treatment performance, sludge conversion yield, changes of temperature and pH, etc. In consequence of this study, factors of temperature correction showed 1.052 on continuous aeration, and 1.056 on intermittent aeration which is more sensitive to temperature through a minute degree. Meanwhile, sludge conversion yield on intermittent aeration showed lower and more economical than that on continuous aeration. In case of changing pH, treatment water of both reactors worsened slightly in acid but improved in alkali. In general. considering the quality of effluent water, variation pH of effluent water, etc. the case of intermittent aeration was more favorable than that of continuous aeration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.113-118
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• 2006

Cost estimation of an intermittent aerobic digestion technology was carried out in this study. Aeration ratio is one of the most important design factors and it affects installation and power consumption cost. For the purpose, digestion efficiency was fixed at 35% of SS reduction and the reactor type was assumed a 2-chamber sequencing batch reactor (SBR). Installation cost and power consumption cost were evaluated and converted in terms of present value that could reflect the rate of discount and the rate of economic growth. The lower aeration ratio needs higher installation cost but lower power consumption cost. From the point of only installation cost, conventional aerobic digestion is cheaper than intermittent aerobic digestion. But intermittent aerobic digestion is better economical for more than 10 years of estimated service life. The optimal aeration ratio was dependent on the service life and it was lower as the estimated service life increased. For the 45 years as the service life, the optimal aeration ratio was estimated 0.3 and the total cost was 64% of the conventional aerobic digestion.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.82-87
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• 2000

생물학적 슬러지를 대상으로 간헐포기 소화와 호기성 소화의 회분실험을 실시하였다. 생물학적 슬러지의 간헐포기 및 호기성 소화 초기단계에서 미생물의 감량은 주로 내생 호흡에 의해 이루어졌다. 이 단계에서 질소는 곧바로 용출되지 않고 슬러지내에 잔존함으로서 슬러지의 질소함량은 일시적으로 증가한다. 그러나 소화후반에서는 최초의 질소함량수준으로 다시 감소하였다. 34일간의 회분식 소화에서 호기성 소화의 총질소 제거효율은 0.1%로서 거의 제거가 안된 반면, 포기 비율 0.25, 05 및 0.75인 간헐포기 소화에서는 각각 42.7%, 42.5% 및 17.6%로 나타나 간헐포기 소화가 호기성 소화보다 질소 제거측면에서 우수하였다. VSS의 감소에 따라 슬러지내의 인도 수중으로 용출하였으나, 인 용출율은 VSS 감소율 보다 훨씬 낮았고 그 결과 소화슬러지의 인 함량은 지속적으로 증가하였다. 호기성 소화와 간헐포기 소화는 소화슬러지의 인 함량이 증가하는 공정이므로 반송수의 인 부하는 상대적으로 낮아지게 되고 이는 하수의 영양염류 제거측면에서 긍정적인 효과를 미칠 것으로 기대된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.119-124
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• 2006

The purpose of this study was the comparison of pollutants removal and the track study of the nitrogen and phosphorus, the estimation of the nitrification and denitrification rate, and the investigation of the nitrogen mass balance between intermittently aerated membrane bioreactor(IAMBR) and intermittently aerated bioreactor(IABR), thus it verified the validity of the membrane submergence. As a result, it had no difference of organic matter removal, however, IAMBR showed better efficiency than IABR in the nutrients. Also, $NO_3{^-}$-N concentration at the anoxic state in the reactor was lower in IAMBR, and the denitrified nitrogen of IAMBR was 40.9%, that of IABR was 10.7%, thus it found out that the denitrification capability of IAMBR was higher than IABR above fourfold. Therefore, it seems resonable to conclude that the membrane helps to improve the removal of pollutants, because of the high MLSS concentration and the available method of intermittent inflow/outflow.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11b
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• pp.51-52
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• 2003

질소제거의 경우 포기 60min인 경우 90% 이상의 제거율을 보였으나, 인 제거를 위해 굴곡점 시간 이후 30분 이상의 비포기 상태를 유지하였을 때 낮은 제거율이 나타났다.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.42-48
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• 2014

In this study, variations of the organic and nitrogenous compounds in wastewater were investigated in a single reactor with intermittent aeration. Over 90% of organic and nitrogen removals are accomplished with C/N ratio of 3 : 1 and 20/20 min of aeration/non-aeration period. Longer non-aeration period on the aeration/non-aeration cycle showed more stable nitrogen removal, showing various microbial community in the reactor. From PCR-DGGE analysis, it is conclusive that Dysgonomonas mossii strain Melo40, Eubacterium sp. oral clone JN088, Uncultured bacterium clone SPESB2_718, and Bacterium enrichment culture clone LE are related with the organics and nitrogen oxidation. Uncultured Acidobacteria bacterium clone AKYG487, Lactobacillus harbinensis strain FQ003, Erythrobacter litoralis strain Gi-3, Phytobacter diazotrophicus strain Ls8, and Mycobacterium sp. enrichment culture clone GE10037biofNNA are distinctly appeared under denitrification condition.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.17-24
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• 2005

This study was carried out to investigate the removal efficiency of an intermittently aerated nonwoven fabric filter bioreactor fed continuously with domestic sewage. The hydraulic retention time(HRT) of the reactor was reduced from 12 hrs to 10 hrs to 8 hrs during an experimental period of 17 months. In order to search an optimum aeration/nonaeration time ratio for the nitrogen removal at each HRT, the cycle times of 3, 2 and 1 hr were tested at the aeration/nonaeration time ratio of 1. Then, the aeration/nonaeration time ratio was changed from 50 min/70 min to 40 min/80 min to 30 min/90 min at the cycle time of 2 hr which showed the best nitrogen removal. During the experimental period, the effluent SS concentration was always below 1.2 mg/L with more than 95% of BOD removal efficiency. The highest nitrogen removal of 90.1% was observed at the aeration/nonaeration time ratio of 40 min/80 min at the HRT of 10 hr. Oxidation-reduction potential could represent the degree of the nitrification and denitrification reaction in the reactor.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.488-498
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• 2016

In order to assess the role of aeration in stormwater wetlands, oxygen supply and consumption in a wetland treating runoff from livestock farms were estimated and analyzed. Furthermore, oxygen mass balance was conducted during day time and night time. Internal production by algal photosynthesis dominated the oxygen production particularly in the shallow marsh due to the large amount of algae. Consequently, algal respiration was also the major oxygen depletion element with nitrification and biodegradation estimated as 5.35% and 6.43% of the total oxygen consumption. This excessive portion of oxygen consumption by algae was associated to the highly turbid water caused by the resuspension of sediment particles in the aeration pond, which also affected the subsequent wetland. Moreover, an abundance of oxygen was estimated during the day indicating that oxygen produced by algal activity is sufficient to meet the oxygen demand in the wetland. Thus, supplemental aeration was deemed not necessary at daytime. In contrast, oxygen was greatly depleted at night when algal photosynthesis stopped which induced denitrification. Therefore, it was suggested that supplemental aeration may be operated continuously instead of intermittently to avoid oxygen deficit in the wetland at night or it may be stopped entirely to further enhance denitrification.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.2
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• pp.257-264
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• 2006

In this study, the treatment of domestic wastewater in a field-scale membrane submerged intermittently aerated activated sludge process($210m^3/day$) was investigated under difference aeration methods. Operating temperature was 5.4 to 25.0 and membrane used in this study is a polyethylene hollow fiber membrane(pore size $0.4{\mu}m$). The range of operating flux was $9.7{\sim}24.4l/m^2-h$ and membrane permeates periodically operated for 7min followed idle for 3 min. The results showed that MIA(modified intermittent aeration) was more efficient in nitrogen and phosphorus removal. The removal efficiencies of T-N and T-P were 73.0% and 69.6% for CIA(conventional intermittent aeration) and 57.5%, 58.6% for MIA (modified intermittent aeration). With application of modified intermittent aeration, DO reached nearly Omg/l within 10 minutes after air off. Organics of influent could be entirely consumed to the denitrification and the P-release without the influence by remained DO in intermittent aeration reactor. Therefore, newly developed KSMBR(Kowaco-KMS-Ssangyoung Membrane Bio-Reactor) process with modified intermittent aeration can be one of the useful process for stable nitrogen and phosphorus removal.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.679-685
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• 2002

The objective of this study was investigated for the microbial community structure and treatment performance of domestic wastewater in lab-scale submerged membrane bioreactor operated with anoxic-oxic cycles. Respiratory quinone profiles were applied as tools for identifying different bacterial populations. The cycle time program of bioreactor was control under anoxic/oxic of 60/90 minutes with an hydraulic retention time of 8.4 hrs. The average $COD_{Cr}$ removal efficiency of domestic wastewater was as high as 93%. The results showed complete nitrification of $NH_4^+$-N generated during oxic period and up to 50% of the total nitrogen could be denitrified. The dominant quinone types of suspended microorganisms in bioreactor were ubiquinone (UQ)-8, -10, followed by menaquinone (MK)-6, and MK-7 for anoxic period, but those for oxic period were UQ-8, MK-6, followed by UQ-10 and MK-7. The microbial diversities of bioreactor at anoxic and oxic periods, calculated based on the composition of all quinones were 10.4 and 12.2-11.8, respectively. The experimental results showed that the microbial community structure in the submerged membrane bioreactor treating domestic wastewater was slightly affected by intermittent aeration.