Kinetic estimation of low excess sludge and extracellular polymeric substance accumulation in a vertical submerged membrane bioreactor (VSMBR)

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
S.R. Chae ◽  
H.S. Chin
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substance ◽  
Membrane Bioreactor ◽  
Transmembrane Pressure ◽  
Yield Coefficient ◽  
Excess Sludge ◽  
Glucose Yield ◽  
Submerged Membrane Bioreactor ◽  
Polymeric Substance ◽  
Micro Organisms

The main objective of this study was to investigate reasons of mitigated membrane fouling based on a mathematical prediction of daily excess sludge (DES) and extracellular polymeric substance (EPS) accumulation in a laboratory-scale vertical submerged membrane bioreactor (VSMBR) fed with glucose. Yield coefficient, growth rate, and decay rate of autotrophic and heterotrophic micro-organisms were estimated by measuring oxygen uptake rate (OUR). From kinetic estimation, it was concluded that the DES from the VSMBR was only 4% of the total DES produced by the activated sludge process (ASP). This resulted from the lower yield biomass and the higher decay of heterotrophic biomass in the VSMBR. In part of the experiment, transmembrane pressure (TMP) was affected by a rapid increase in EPS concentration. Later, a second rapid increase of TMP was observed although EPS concentration was stable indicating that the second increase of TMP was caused by interfiber clogging other than EPS accumulation.

Analysis of extracellular polymeric substance (EPS) release in anaerobic sludge holding tank and its effects on membrane fouling in a membrane bioreactor (MBR)

2014 ◽  
Vol 70 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Byeong-Cheol Kim ◽  
Duck-Hyun Nam ◽  
Ji-Hun Na ◽  
Ki-Hoon Kang
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substance ◽  
Membrane Bioreactor ◽  
Batch Reactor ◽  
Pilot Scale ◽  
Anaerobic Sludge ◽  
Sudden Increase ◽  
Sludge Reduction ◽  
Successful Operation ◽  
Polymeric Substance

Amongst sludge reduction strategies, the anaerobic side-stream sludge holding tank (SHT) is of particular interest because it has shown significant sludge reduction efficiency. However, due to the anaerobic and starving environment of the SHT, the release of extracellular polymeric substance (EPS) may be stimulated, and it may hamper the application of the SHT to the membrane bioreactor. In order to investigate the effect of sludge storage on EPS release, sludge samples from a pilot-scale sequencing batch reactor coupled with SHT was incubated in a series of bench-scale SHT reactors for different periods of time (0–24 h). The increase in EPS was not significant until 12 h of incubation (9.3%), while 40.9% of the increase was observed in the sample incubated for 24 h. The rapid increase in EPS concentration after 12 h indicates a greater rate of cell lysis than that with EPS consumption as substrate. Since inducing the initial stage of the endogenous phase within microorganisms is a key factor for the successful operation of the SHT for sludge reduction, the retention time for the SHT should be shorter than the time for the sudden increase in EPS release.

A venturi device reduces membrane fouling in a submerged membrane bioreactor

2016 ◽  
Vol 74 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Necati Kayaalp ◽  
Gokmen Ozturkmen
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Oxygen Transfer Rate ◽  
Surface Cleaning ◽  
Aeration Rate ◽  
Transmembrane Pressure ◽  
Submerged Membrane Bioreactor ◽  
System A ◽  
Do Concentration

In this study, for the first time, a venturi device was integrated into a submerged membrane bioreactor (MBR) to improve membrane surface cleaning and bioreactor oxygenation. The performances of a blower and the venturi device were compared in terms of membrane fouling and bioreactor oxygenation. Upon comparing membrane fouling, the performances were similar for a low operation flux (18 L/m2.h); however, at a medium flux (32 L/m2.h), the venturi system operated 3.4 times longer than the blower system, and the final transmembrane pressure was one-third that of the blower system. At the highest flux studied (50 L/m2.h), the venturi system operated 5.4 times longer than the blower system. The most notable advantage of using a venturi device was that the dissolved oxygen (DO) concentration of the MBR was in the range of 7 to 8 mg/L at a 3 L/min aeration rate, while the DO concentration of the MBR was inadequate (a maximum of 0.29 mg/L) in the blower system. A clean water oxygenation test at a 3 L/min aeration rate indicated that the standard oxygen transfer rate for the venturi system was 9.5 times higher than that of the blower system.

Effect of a suspended carrier on membrane fouling in a submerged membrane bioreactor

2006 ◽  
Vol 53 (6) ◽  
pp. 211-220 ◽  
Author(s):  
Chun-Hai Wei ◽  
Xia Huang ◽  
Cheng-Wen Wang ◽  
Xiang-Hua Wen
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Transmembrane Pressure ◽  
Fouling Control ◽  
Submerged Membrane Bioreactor ◽  
Negative Effect ◽  
Sludge Particle ◽  
Carrier Volume ◽  
Suspended Carrier

In an attempt at membrane fouling control, a kind of cylindrical plastic suspended carrier was added in a submerged membrane bioreactor (SMBR) and its effect was investigated in this study. According to the transmembrane pressure (TMP) profiles and the sludge characteristics in comparative runs with and without suspended carriers, it was found that the suspended carriers added in SMBR had two effects on membrane fouling: one was the positive effect of mechanically scouring the membrane surface and the other was the negative effect of breaking up sludge flocs. Sludge particle size distribution change was mainly responsible. It was suggested to apply the suspended carrier at higher MLSS concentration and lower carrier dose based on the consideration for retarding sludge breakage caused by the carrier. The experiment was conducted under higher MLSS (8 g L−1) and lower carrier dose (carrier volume/total volume = 1%). The TMP increase was effectively retarded by added suspended carriers compared to the system without addition of the carriers. The effect of suspended carriers on membrane fouling at high MLSS concentration was verified.

scholarly journals Effect of cycle run time of backwash and relaxation on membrane fouling removal in submerged membrane bioreactor treating sewage at higher flux

2017 ◽  
Vol 76 (4) ◽  
pp. 963-975 ◽  
Author(s):  
Shamas Tabraiz ◽  
Sajjad Haydar ◽  
Paul Sallis ◽  
Sadia Nasreen ◽  
Qaisar Mahmood ◽  
...  
Keyword(s):  
Cycle Time ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Operation Time ◽  
High Rate ◽  
High Flux ◽  
Submerged Membrane Bioreactor ◽  
Time Ratio ◽  
Effective Operation ◽  
Run Time

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.

Sign in / Sign up

Export Citation Format

Share Document