30 LMH의 정유량 플럭스로 운전하는 MBR에서, 휴지 및 역세정에 따른 한외여과 분리막의 오염을 조사하였다. 또한, 연속적인 공기세정과 비교하여 분리막 여과저항을 최소화하기 위한 간헐적인 공기세정을 평가하였다. 여과 조건은 14.5분 여과와 0.5분의 휴지를 유지하였으며, 역세정 시간은 휴지 시간과 동일하게 운전하였다. 공기세정이 정지하는 동안에 분리막 표면의 겔층 위에 케?이 빠르게 축척되었으며, 역세정으로 겔층과 케?층의 복합층은 쉽게 제거되었다. 역세정 후에 공기세정이 정지하는 동안 분리막 표면에 케?이 형성되어 공경 내부의 오염현상을 억제하였다. Pearson 상관성을 조사한 결과, 간헐적인 공기세정에서 공기 세정이 정지하는 시간과 분리막의 오염은 매우 연관성이 높다는 것을 알았다. 즉, 간헐적인 세정에서 공기세정이 정지하는 시간이 갈수록 오염억제에 효과적이었다.
30 LMH의 정유량 플럭스로 운전하는 MBR에서, 휴지 및 역세정에 따른 한외여과 분리막의 오염을 조사하였다. 또한, 연속적인 공기세정과 비교하여 분리막 여과저항을 최소화하기 위한 간헐적인 공기세정을 평가하였다. 여과 조건은 14.5분 여과와 0.5분의 휴지를 유지하였으며, 역세정 시간은 휴지 시간과 동일하게 운전하였다. 공기세정이 정지하는 동안에 분리막 표면의 겔층 위에 케?이 빠르게 축척되었으며, 역세정으로 겔층과 케?층의 복합층은 쉽게 제거되었다. 역세정 후에 공기세정이 정지하는 동안 분리막 표면에 케?이 형성되어 공경 내부의 오염현상을 억제하였다. Pearson 상관성을 조사한 결과, 간헐적인 공기세정에서 공기 세정이 정지하는 시간과 분리막의 오염은 매우 연관성이 높다는 것을 알았다. 즉, 간헐적인 세정에서 공기세정이 정지하는 시간이 갈수록 오염억제에 효과적이었다.
The effects of relaxation and backwashing on fouling in ultrafiltration were investigated using full-scale membrane bioreactors (MBRs) which operated at a constant flux of 30 LMH. This paper also estimated the feasibility of using intermittent aeration strategies for minimizing the hydraulic resista...
The effects of relaxation and backwashing on fouling in ultrafiltration were investigated using full-scale membrane bioreactors (MBRs) which operated at a constant flux of 30 LMH. This paper also estimated the feasibility of using intermittent aeration strategies for minimizing the hydraulic resistance to filtration in comparison with the continuous aeration for running MBRs. Multiple cycles of filtration (14.5 min each) and relaxation (0.5 min each) were repeated. Similarly, a backwash was conducted by replacing a relaxation after each filtration cycle for the comparative performance test. The attached cake thickness on the membrane rapidly increased, caused by subsequent no aeration leading to easier combining with gel layer and the formation of heterogeneous layer on the membrane surface. During periodic backwashing, it is expected that gel and thin cake layer might sufficiently be removed by heterogeneous layer. After periodic backwashing, subsequent cake layer formation during time of no aeration was rapid than frequent no aeration, acting as a prefilter and preventing further irreversible fouling. Based on the Pearson correlation analysis, overall period fouling (dTMP/min) and average of all cycles (dTMP/min) were strongly correlated with the on-off period of aeration for operating MBRs.
The effects of relaxation and backwashing on fouling in ultrafiltration were investigated using full-scale membrane bioreactors (MBRs) which operated at a constant flux of 30 LMH. This paper also estimated the feasibility of using intermittent aeration strategies for minimizing the hydraulic resistance to filtration in comparison with the continuous aeration for running MBRs. Multiple cycles of filtration (14.5 min each) and relaxation (0.5 min each) were repeated. Similarly, a backwash was conducted by replacing a relaxation after each filtration cycle for the comparative performance test. The attached cake thickness on the membrane rapidly increased, caused by subsequent no aeration leading to easier combining with gel layer and the formation of heterogeneous layer on the membrane surface. During periodic backwashing, it is expected that gel and thin cake layer might sufficiently be removed by heterogeneous layer. After periodic backwashing, subsequent cake layer formation during time of no aeration was rapid than frequent no aeration, acting as a prefilter and preventing further irreversible fouling. Based on the Pearson correlation analysis, overall period fouling (dTMP/min) and average of all cycles (dTMP/min) were strongly correlated with the on-off period of aeration for operating MBRs.
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문제 정의
Finding the importance of optimizing no aeration time, this study aims to identify the effect of no aeration time including backwashing and relaxation conditions on the optimum no aeration time. Additionally, an insight into the effects on the hydraulic resistance is assessed, and Pearson correlation analysis was done to identify the major contributor to membrane fouling.
In this study, the MBRs for the treatment of real wastewater at an existing wastewater plant (WWTP) was operated by directly submerging the pilot scale YEF module into oxic basin in order to investigate the performance and fouling of membrane module. The hydraulic retention time (HRT) as well as biomass (MLSS) of MBRs are shown in Table 2.
In the different concentration of mixed liquid suspended solid (MLSS), superficial liquid velocity of YEF module was investigated to determine dependence on aeration intensity. The one of the main objective of this research is that YEF module presents specific flow pattern as to superficial liquid velocity.
Table 1 shows the characteristics of the membrane used. The present study was carried out to obtain further insight into the characteristics of filtra tion of the submerged YEF module.
가설 설정
313 m3/m2⋅hr of aeration intensity in all the applied MLSS concentration, as shown in Fig. 5. The effect of aeration intensity on superficial liquid velocity improvement is higher lower RLSS concentration. Accordingly, superficial liquid velocity was dependent on MLSS concentration.
With different concentration of MLSS, the superficial liquid velocity of YEF module increased with increasing the aeration intensity as shown in Fig. 5. The superficial liquid velocity depends on the MLSS concentration, decreased with increasing the MLSS concentration. The reduction rate of the superficial liquid velocity was found to be 3 × 10-4 m⋅m2⋅hr/sec⋅m3 per 1,000 mg MLSS/L.
제안 방법
Finding the importance of optimizing no aeration time, this study aims to identify the effect of no aeration time including backwashing and relaxation conditions on the optimum no aeration time. Additionally, an insight into the effects on the hydraulic resistance is assessed, and Pearson correlation analysis was done to identify the major contributor to membrane fouling.
2). This study was run without filtration because the main objective was to characterize the flow induced by the aeration. A further study will be carried out with the filtration in order to determine the impact of the filtration on the flow hydrodynamics.
To evaluate the fouling distribution of the different aeration modes, fouling propensity was monitored by continuous TMP measurement and a detailed analysis of the hydraulic resistances based on Darcy’s law (Eq.
Two different aeration (i.e. continuous and intermittent) and three filtration modes were applied and evaluated in terms of hydraulic performances and its resistances (Table 4). The filtration flux was 30 LMH (L/m2⋅hr).
대상 데이터
3). For this test, the equipment was composed of velocity meter (BFM002, Valeport), signal transmitter and personal computer for the data acquisition. Air holes existed at bottom of YEF module.
3, which was located in Yonsei University Wonju campus, consisted of anoxic and oxic basin. The filtration system consisted of a reactor column a YEF element, permeate pump (gear flex type, DAESUNG Co., Ltd), blower (roots type, JUNGSUN Co., Ltd), pressure gauge (PMC731, Endress Hauser), electronic flowmeter (Promag 30, Endress Hauser) and computer. The pump operated in forward and backward directions for the suction of permeate and the backwashing.
데이터처리
Since Pearson correlation shows the clear relationship than linear correlation to predict the significant effect of operation parameters. Pearson correlation analysis was performed to identify the correlation between overall TMP rate and average of all cycles TMP rate for each experiment under different off-time of intermittent aeration. While analyzing the Pearson correlation in this study, only 20-s with on-time of intermittent aeration was applied, indeed in defined backwashing mode.
11. Relationship between overall period (dTMP/min) and average of cycle (dTMP/min) for different off-time of intermittent aeration by Pearson correlation analysis.
성능/효과
The YEF module of liquid velocity is very uniform at all the measuring points as shown in Fig. 4. It was indicated that configuration of YEF module was profitable rectilinear, therefore, the superficial liquid velocity increased with increasing the aeration intensity. With different concentration of MLSS, the superficial liquid velocity of YEF module increased with increasing the aeration intensity as shown in Fig.
후속연구
This study was run without filtration because the main objective was to characterize the flow induced by the aeration. A further study will be carried out with the filtration in order to determine the impact of the filtration on the flow hydrodynamics.
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