• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.243-248
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• 1999

Ultrasonic wave technology was employed to improve filtration performance and ethanol production in a bioreactor equipped with an internal ceramic-membrane filter module. The filtration performance was found to depend on the power and the pattern of ultrasonic wave irradiation. Under the optimized conditions (irradiation time: 25 see, period: 5 min, and ultrasonic power: 60 W), the flux was improved with the periodic-pause method by 200-700％ compared with the control (with no irradiation), while the improvement was only 30 to 90％ without the periodic-pause method. The final ethanol concentration also increased slightly. However, in a more severe condition (irradiation time: 2.5 min, period: 5 min, and ultrasonic power: 110 W), the irradiation of ultrasonic waves was observed to disturb cell integrity and viability, and thus to decrease ethanol production.

• 멤브레인
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• 제11권4호
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• pp.170-178
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• 2001

상전환 방법에 의해 PVC계 MF막을 제조하여 환성슬러지가 포함된 폐수 처리용 MBR (Membrane bioreactor)에 적용하였다. 막 제조시 첨가제의 농도에 따른 막 특성을 확인한 결과 첨가제의 농도가 증가할수록 기공 크기가 증가하였으며 친수화도 역시 향상되었다. MBR의 내부 환경변화에 따른 실험을 통해 제조한 막의 투과 성능 및 막에 발생하는 막 오염 거동을 조사하였다. 사상균의 생성으로 인한 Sludge bulking 시 막 오염 현상이 가속화되었으며, 이 때 각 시료의 Rc을 조사한 결과 CP-0 > CP-1.0 > CP-1.5의 순으로 나타났고, 정상상태와 비교하여 sludge busking시 Rc값은 3.5~7배가지 증가하였다. 표면 특성이나 투과 유속면에서 PVP 1.5 wt% (CP-1.5)를 첨가하였을 때가 가장 적합하였다. 평균 투과 유속은 시료 모두에서 12(${\pm}$2) L/$m^2$hr 정도였으며, 평균 COD 제거율은 98.8% 정도를 나타내었다 MBR 운전에 있어 sludge bulking시 사상균이 차지하는 비율과 미생물의 모양과 크기에 따라 막 오염은 가속화 되었고, 투과 유속 감소를 보였다. 따라서 막 여과 특성은 막의 친수화 정도와 MBR 내부 미생물의 성장 조건과 환경에 의해 결정되는 것을 알 수 있었다.

• 한국물환경학회지
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• 제25권1호
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• pp.120-124
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• 2009

This study was performed to investigate the application of submerged membrane bioreactor (MBR) system for biological nutrient removal of municipal wastewater. MBR bioreactor consists of four reactors such as anaerobic, stabilization, anoxic and submerged membrane aerobic reactors with two internal recycles. The hydraulic retention time (HRT), sludge retention time (SRT) and flux were 6.2 hr, 34.1 days and $19.6L/m^2/hr$ (LMH), respectively. As a result of operation, the removal efficiency of $COD_{Cr}$, SS, TN and TP were 94.3%, 99.9%, 69.4%, and 74.6%, respectively. There was no significant effect of microbial activity after the maintenance cleaning using 200 mg/L of NaOCl. Membrane filtration for the treatment of municipal wastewater was performed for longer than 9 months without chemical recovery cleaning.

• Environmental Engineering Research
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• 제17권2호
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• pp.59-63
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• 2012

This paper proposes a modified Ludzack-Ettinger (MLE) type membrane bioreactor (MBR) as a method of treatment for wastewater from food waste disposer. Micro-membrane filtration allows for an extremely low concentration of suspended solids in the effluent. The effluent of the reactor in question is characterized by a relatively high level of non-biodegradable organics, containing a substantial amount of soluble microbial products and biomass. Results obtained in this paper by measurement of membrane fouling are consistent with biomass concentration in the reactor, as opposed to chemical oxygen demand (COD). The MLE process is shown to be effective for the treatment of wastewater with a high COD/N ratio of 20, resulting in are markedly high total nitrogen removal efficiency. Denitrification could be improved at a higher internal recycle ratio. Despite the low concentration of influent phosphorus, the phosphorus concentration of the outflow is seen to be relatively high. This is because outflow phosphorous concentration is related to COD consumption, and the process operates at along solids retention time.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.338-341
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• 2000

An internal membrane bioreactor system was employed for continuous succinic ac id production from glucose in order to prove its performance and practicality. Succinic acid-producing Anaerobiospirillum succiniciproducens required more $CO_2$ for the proper growth and succinic acid production in cell recycled continuous culture than in batch culture. The maximum productivity obtained in cell recycled continuous culture was about 3.3 g/L-h which was ca. 3.3 times higher than that obtained in batch culture.

• Advances in environmental research
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• 제7권1호
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• pp.39-52
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• 2018

Direct membrane filtration (DMF) of wastewater has many advantages over conventional biological wastewater treatment processes. DMF is not only compact, but potentially energy efficient due to the lack of biological aeration. It also produces more biosolids that can be used to produce methane gas through anaerobic digestion. Most of ammoniacal nitrogen in wastewater is preserved in effluent and is used as fertilizer when effluent is recycled for irrigation. In this study, a technical feasibility of DMF was explored. Organic and nitrogen removal efficiencies were compared between DMF and membrane bioreactor (MBR). Despite the extremely high F/V ratio, e.g., $14.4kg\;COD/m^3/d$, DMF provided very high COD removal efficiencies at ~93%. Soluble microbial products (SMP) and extracellular polymeric substances (EPS) were less in DMF sludge, but membrane fouling rate was far greater than in MBR. The diversity of microbial community in DMF appeared very narrow based on the morphological observation using optical microscope. On the contrary, highly diverse microbial community was observed in the MBR. Microorganisms tended to form jelly globs and attach on reactor wall in DMF. FT-IR study revealed that the biological globs were structurally supported by feather-like materials made of secondary amines. Confocal laser scanning microscopy (CLSM) study showed microorganisms mainly resided on the external surface of microbial globs rather than the internal spaces.