• Membrane and Water Treatment
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• 제3권3호
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• pp.141-149
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• 2012

The aeration provided in a Submerged Membrane Bioreactor (SMBR) improves membrane filtration by creating turbulence on the membrane surface and reducing membrane resistance. However, conventional hollow fiber membrane modules are generally packed in a vertical orientation which limits membrane scouring efficiency, especially when aeration is provided in the axial direction. In the present research, 3 innovative hollow-fiber membrane modules, each with a different membrane orientation, were developed to improve membrane scouring efficiency and enhance permeate flux. Pilot testing was performed to investigate the permeate flux versus time relationship over a 7-day period under different intermittent modes. The results indicated that the best module experienced an overall permeate flux decline of 3.3% after 7 days; the other two modules declined by 13.3% and 18.3%. The lower percentage of permeate flux decline indicated that permeate productivity could be sustained for a longer period of time. As a result, the operational costs associated with membrane cleaning and membrane replacement could be reduced over the lifespan of the module.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 춘계 총회 및 학술발표회
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• pp.141-144
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• 2003

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 제6회 하계 Workshop (98 한국막학회, 국립환경연구원 국제 Workshop, 수자원 보전과 막분리 공정)
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• pp.113-133
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• 1998

In activated sludge process, sludge settling condition is affected by organic loading rate or operation condition, and if settling condition is getting worse, it is common that overall process fails due to wash-out of biomass causing low concentration in the aeration tank. Also activated sludge process has such several problems as requiring large area, consuming a lot of power and producing large volume of sludge. Increased public concern over health and the environment combined with a strong desire to reduce capital, operating and maintenance costs, have created a need for innovative technologies for building new high quality effluents which vail meet 21st century crkeria. MBR(Membrane Bioreactor) process consists of a biological reactor and ultrafiltration(UF) membrane system that replaces the conventional clarifier of an activated sludge process. The main operating advantages of this system are that the quality of the effluent is independent of the settleability of the mixed liquor and that the effluent is free of suspended solids in any operating condition. It is possible to eliminate clarifier and to reduce the volume of aeration tank because it can afford to accumulate high biomass concentration in the bioreactor(20, 000~30, 000mg/L), which would not be possible in a conventional activated sludge process. Therefore, this process reduces overall treatment plant area. In addition to those advantages, Longer SRT condition enables higher sludge digestion in MBR process so the sludge volume produced is 50 to 70% lower than that of conventional activated sludge process There are two kinds of MBR process according to the allocations of membrane. One is cross flow type MBR of which module is located outside of the bioreactor and mixed liquor is driven into the membrane module. The other is submerged type MBR process of which module is submerged in the bioreactor and mixed liquor is generally sucked from the lumen side. addition to that the cake layer is often removed by the uplifting flow of bubbling air. A submerged MBR process is superior to a crossflow MBR in regard to the power consumption because suction pressure of a submerged MBR is generally lower than that of a crossflow MBR which has recirculation pump. A submerged MBR, therefore, has the potential to be applied to small wastewater treatment plants that need low cost treatment systems.

• Korean Chemical Engineering Research
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• 제53권5호
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• pp.646-652
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• 2015

본 연구에서는 emulsion 및 semi-synthetic 절삭유 수용액에 침지된 평막형 분리막의 막간 압력차(TMP)를 투과유속에 따라서 측정하였다. 사용한 정밀여과막은 유효 막면적이 $0.02m^2$이고 공칭 세공크기가 $0.15{\mu}m$이었다. 저장조 내에 2개의 분리막 모듈을 침지시키고 운전/휴직(R/S) 및 사인파형 투과유속 연속운전(SFCO) 실험을 동시에 실시하였다. Emulsion 수용액의 경우 SFCO에 의한 TMP는 R/S에 비하여 60% 이하로 유지되었으며 투과유속이 증가함에 따라서 TMP 감소효과는 줄어들었다. Semi-synthetic 수용액은 emulsion 수용액보다 탁도가 낮아 막오염이 적게 유발되었으며 장시간 운전할 경우 SFCO에 의한 TMP 효과도 감소하였다.

• 상하수도학회지
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• 제16권6호
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• pp.717-725
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• 2002

A bench-scale submerged-type membrane filtration system (SMFS) was constructed to study a feasibility of membrane filtration for solid-liquid separation in water and wastewater treatment processes. In the case of applying the SMFS to a biological wastewater treatment process, so-called membrane bioreactor, aeration underneath membrane modules is usually employed in order to provide oxygen demand for microbial growth as well as to control membrane fouling. A study was investigated the effects of operation parameters by aeration intensity, feed concentration, foulant type and airlift pore size on critical flux. Critical flux tends to increase with aeration rate. Optimal aeration flow rate was found to be 10 L/min/module. Feed concentration and foulant type has a significant effect on membrane fouling and filtration performance. But downward position and pore size of airlift has no a significant effects on membrane fouling and filtration performance.

• 한국환경과학회지
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• 제9권2호
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• pp.173-176
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• 2000

This study was carried out to investigate the filtration characteristics of membrane modules according to hollow fiber dispersion for direct solid-liquid separation of activated sludge. 2 bundle, 4 bundle, and 10 bundle, and 10 bundle module used in this experiment according to hollow fiber dispersion was manufactured at laboratory and permeate flux and transmembrane pressure(TMP) of each module were observed under a suction pressure of 0.5kgf/c$m^2$. As the hollow fibers were dispersed, permeate flux was increased and TMP was decreased. Permeate flux and TMP of each module was 15.0 $\ell$/$m^2$.h and 31.8 cmHg for 2 bundle, 16.0 $\ell$/$m^2$ .h and 17.4 cmHg for 4 bundle, and 20.4 $\ell$/m2 .h and 31.8 cmHg for 10 bundle. In conclusion, the membrane fouling is expected to be decrease by maintaining lower TMP with hollow fiber dispersion.

• 멤브레인
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• 제25권3호
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• pp.268-275
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• 2015

침지식 분리막 모듈에서 공기강도에 따른 분리막 위치에 대한 오염을 조사하였다. 분리막의 충진밀도가 낮은 곳에서 높은 유체 유속을 나타내었으며, 유체 속도는 기-액 주입률에 비례하였다. 전단응력은 기-액 주입률 및 유체 유속에 비례하였다. 비가역오염($R_{ir}$)은 흡입 압력이 가까운 부분에서 가장 높게 나타났다(position 1). 비가역오염에 대한 저항과 분리막 고유 저항의 비($R_{ir}/R_m$) 및 비가역오염에 대한 저항과 가역오염의 저항의 비($R_{ir}/R_r$)도 position 1에서 가장 높게 조사되었다. 비가역오염($R_{ir}$)은 흡입 압력이 높은 곳인 position 1에 오염물질이 축적되어진 결과이다. 분리막 위치에 따른 오염현상은 모듈 디자인 최적화에 중요한 인자임을 알았다.

• 멤브레인
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• 제16권1호
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• pp.51-58
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• 2006

본 연구는 침지형 분리막 모듈에 자체 설계한 회전원판을 적용하여 운전시간 경과에 따른 막오염 감소효과와 최적의 운전조건을 투과실험으로 알아보았다. 원료용액으로는 kaolin과 bentonite를 농도별로 제조하여 사용하였고, 원판의 회전수를 120 rpm까지 변화시키면서 60분 동안 실험하였다. 회전원판에 의한 막오염 감소 효과로 kaolin 수용액을 대상으로 한 실험에서는 흡입압력이 약 28%까지 감소하였다. 또한 kaolin 농도에 따라서 최적 투과유속이 감소하였으며 0.4wt% 일 경우는 60 내지 70 LMH가 적당하였다. Bentonite 수용액에 대하여 투과유속이 30 LMH 일 경우에 원판의 회전속도가 80 rpm 이상이 되면 흡입압력이 대략 0 mmHg에 접근하였다.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.7-10
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• 2003

Factors affecting filtration performance were investigated in a Sequencing Batch Reactor (SBR) coupled with a submerged microfiltration module. Special bioreactors for aerobic and anoxic phases, respectively, were specifically designed in order to differentiate tile effect of Dissolved oxygen (DO) from that of mixing intensity on membrane filterability. DO concentration as well as mixing intensity proved to have a major influence on the membrane performance regardless of the SBR phase. A higher DO concentration resulted in a slower rise in TMP, corresponding to less membrane fouling.

• 멤브레인
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• 제28권4호
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• pp.279-285
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• 2018

이소프로필알코올/물 혼합물은 가교된 폴리비닐알코올 복합막을 이용하여 투과특성평을 알아보았다. 검화도가 다른 3종 PVA를 이용하여 고분자의 농도와 GA 농도에 따라서 투과특성을 확인하였다. 복합막은 PVA 용액을 PAN 지지체 위에 캐스팅한 후, 열가교를 통해 제조하였다. PVA 농도가 증가할수록 투과도는 감소하지만 선택도는 증가하는 것을 확인하였다. PVA-3이 7 wt% 농도로 코팅된 복합막에서 $209g/m^2h$의 투과도를 가지고, 100 이상의 선택도를 가지는 것을 확인하였다. 침지형 분리막을 제조하여 feed tank 온도와 feed 용액의 IPA 농도에 따라서 투과실험을 확인하였다. 또한 IPA 수용액에 농축실험을 지속적으로 한 결과, 60시간 후에 IPA의 농도가 99%까지 증가하는 것을 확인하였다.