Potential and limitations of alum or zeolite addition to improve the performance of a submerged membrane bioreactor

2001 ◽  
Vol 43 (11) ◽  
pp. 59-66 ◽  
Author(s):  
J. C. Lee ◽  
J. S. Kim ◽  
I. J. Kang ◽  
M. H. Cho ◽  
P. K. Park ◽  
...  

In this study, alum and natural zeolite were added to a submerged membrane bioreactor (MBR) not only to reduce membrane fouling but also to increase the removal of nitrogen and phosphorus. Alum addition reduced significantly the rising rate of suction pressure and also resulted in stable and better COD removal. Although phosphorus removal was more than 90% by chemical precipitation, nitrification inhibition was observed. With the addition of natural zeolite, membrane permeability was greatly enhanced by the formation of rigid floc that had lower specific resistance than that of the control activated sludge floc. In particular, the nitrification efficiency was over 95% even at N-shock loading due to the ion-exchange capacity of zeolite. The mechanisms for improved membrane permeability through alum or zeolite addition were discussed in detail.

2013 ◽  
Vol 699 ◽  
pp. 291-297
Author(s):  
Xiao Nan Feng ◽  
Tao Tao ◽  
Hao Xi ◽  
Yong Tao Xu ◽  
Hong Feng Wang ◽  
...  

.Membrane bioreactor (MBR) is considered to be a promising technology for combine biological with filtration and many advantages over conventional activated sludge (CAS) processes. In this study, the submerged membrane bioreactor which was explored by our research group and JDL Environmental Protection Ltd. at condition of aerobic-MBR and SBR-MBR were investigated. Hydraulic characteristics of MBR by the tracer experiments showed the total dead space (Vd, %) in the MBR was 3.2%. Compared with aerobic-MBR situation, the SBR-MBR exhibited better performance of average NH4+-N, total nitrogen, and phosphorus removal efficiency 90%, 86%, 57% respectively. The content of protein was correlated to sludge activity and organic matter. The initial membrane fouling was caused by layer pollution and subsequently the extra-cellular polymeric substances (EPS) contributed.


2004 ◽  
Vol 4 (1) ◽  
pp. 135-142 ◽  
Author(s):  
H. Shin ◽  
S. Kang ◽  
C. Lee ◽  
J. Lim

The submerged membrane bioreactor is one of the recent technologies for domestic wastewater treatment. In this study, the performance of the pilot-scale submerged membrane bioreactor coupled with sequencing batch reactor (SM-SBR) was investigated. The reactor was operated in sequencing batch modes with a 3-hour cycles consisting of anoxic and aerobic conditions to treat organics, nitrogen and phosphorus. Despite large fluctuations in influent conditions, COD removal was found to be higher than 95%. Sufficient nitrification was obtained within a few weeks after start-up and during the stable period. Moreover, complete nitrification occurred despite of short aeration time. Total nitrogen (TN) removal efficiency was up to 85%. The insufficient organic loading caused by the membrane fouling led to the increase of HRT, leading to endogenous respiration and/or deactivation of nitrifying microorganisms. DGGE patterns confirmed the shift in microbial community structure. The ammonia-oxidizers (i.e. Nitrospira) became dominant in the mixed liquor during long-term operations. Nitrification and denitrification processes were greatly affected by the temperature, while organic removal and phosphorus removal efficiencies were relatively stable below 15°C.


2004 ◽  
Vol 31 (4) ◽  
pp. 349-356
Author(s):  
Li Na ◽  
Li Zhidong ◽  
Li Guode ◽  
Wang Yan ◽  
Wu Shiwei ◽  
...  

2017 ◽  
Vol 76 (4) ◽  
pp. 963-975 ◽  
Author(s):  
Shamas Tabraiz ◽  
Sajjad Haydar ◽  
Paul Sallis ◽  
Sadia Nasreen ◽  
Qaisar Mahmood ◽  
...  

Intermittent backwashing and relaxation are mandatory in the membrane bioreactor (MBR) for its effective operation. The objective of the current study was to evaluate the effects of run-relaxation and run-backwash cycle time on fouling rates. Furthermore, comparison of the effects of backwashing and relaxation on the fouling behavior of membrane in high rate submerged MBR. The study was carried out on a laboratory scale MBR at high flux (30 L/m2·h), treating sewage. The MBR was operated at three relaxation operational scenarios by keeping the run time to relaxation time ratio constant. Similarly, the MBR was operated at three backwashing operational scenarios by keeping the run time to backwashing time ratio constant. The results revealed that the provision of relaxation or backwashing at small intervals prolonged the MBR operation by reducing fouling rates. The cake and pores fouling rates in backwashing scenarios were far less as compared to the relaxation scenarios, which proved backwashing a better option as compared to relaxation. The operation time of backwashing scenario (lowest cycle time) was 64.6% and 21.1% more as compared to continuous scenario and relaxation scenario (lowest cycle time), respectively. Increase in cycle time increased removal efficiencies insignificantly, in both scenarios of relaxation and backwashing.


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