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.

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.

Application of response surface methodology for investigation of membrane fouling behaviours in microalgal membrane bioreactor: the effect of aeration rate and biomass concentration

RSC Advances ◽  
2016 ◽  
Vol 6 (112) ◽  
pp. 111182-111189 ◽  
Author(s):  
Atefeh Alipourzadeh ◽  
Mohammad Reza Mehrnia ◽  
Ahmad Hallaj Sani ◽  
Azadeh Babaei
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Biomass Concentration ◽  
Aeration Rate ◽  
Submerged Membrane Bioreactor

This study was performed to investigate membrane fouling phenomena and to optimize fouling parameters in a submerged membrane bioreactor.

scholarly journals Effect of Mixed Liquor Volatile Suspended Solids on Membrane Fouling During Short and long-term Operation of Membrane Bioreactor

2015 ◽  
Vol 11 (21) ◽  
pp. 137-155 ◽  
Author(s):  
Edson Baltazar Estrada-Arriaga ◽  
Petia Mijaylova Nacheva ◽  
Liliana García-Sánchez
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Membrane Surface ◽  
Waste Water Treatment ◽  
Critical Flux ◽  
Term Operation ◽  
Mixed Liquor ◽  
Submerged Membrane Bioreactor ◽  
The Impact

The aim of this study was to examine the impact of different Mixed Liquor Volatile Suspended Solids (MLVSS) concentrations on membrane fouling,in a submerged Membrane Bioreactor (MBR) at short and longterm MBRoperation for waste water treatment. Three laboratory-scale in a submerged MBR system were operated under critical flux, subcritical flux,and an intermittent suction time and backwashing conditions. At short-term MBR operation with mixed liquors of 4,200 and 6,150 mg MLVSSL−1, the hydraulic resistance of membranes followed a same trajectory with averages of 5.0E+12m−1, whereas for 7,940 mg MLVSSL−1, a highresistance of up to 1.7E+13m−1was obtained. The result showed thathigh biomass concentrations decreased to permeability due to a bio-layer formed in the membrane surface and high Extracellular Polymeric Substance (EPS).

Effect of Aeration Conditions on the Flow Field in the Submerged Membrane Bioreactor

2014 ◽  
Vol 535 ◽  
pp. 539-546 ◽  
Author(s):  
Shi Lu Xing ◽  
Zhong Lan Tao ◽  
Jian Ming Niu ◽  
Rui Tian ◽  
Chun Li Li
Keyword(s):  
Membrane Bioreactor ◽  
Flow Model ◽  
Liquid Velocity ◽  
Membrane Surface ◽  
Gas Holdup ◽  
Aeration Rate ◽  
Two Phase ◽  
Submerged Membrane Bioreactor ◽  
Aeration Conditions ◽  
Simulation Results

A full size 3D numerical simulation of gas liquid two-phase flow in a submerged membrane bioreactor was carried out. The standard k-ε turbulence model and Euler multiphase flow model of fluent were used. The effect of changed aeration conditions in the reactor on the gas holdup and gas-liquid velocity distribution in the reactor was studied. The simulation results were shown that, at the same aeration rate, the liquid and gas velocities of 1mm hole aerated at the membrane surface increased faster than 2 mm and 3mm aeration holes; At the same aeration hole , with the increase of aeration rate，the liquid and gas velocities at the membrane surface increased; At the 1mm aeration hole and 5.5m3/h aeration rate, the vortex area was larger and gas holdup was higher, so that gas and liquid were contacting well and the membrane surface scouring effect was better; The Simulation also shown that local gas holdup was lower at close to the wall at the bottom of the reactor, this was not conducive to the growth of microorganisms in the activated sludge, the need to further optimize the structure of aeration and reactor.

Effect of Suspended Carriers on Extracellular Polymeric Substances in MBR

2014 ◽  
Vol 955-959 ◽  
pp. 1939-1943
Author(s):  
Chun Hua Zhang ◽  
Xiao Xia Ou ◽  
Feng Jie Zhang
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Aeration Rate ◽  
Woven Fabric ◽  
Membrane Model ◽  
Synthetic Wastewater ◽  
Model Surface ◽  
Submerged Membrane Bioreactor

Suspended carriers were added into a submerged membrane bioreactor (SMBR) using polypropylene non-woven fabric (PP NWF) as membrane model to treat synthetic wastewater. The changes of EPSSEPSB and EPS in activated sludge mixing liquid of MBR and in sludge on membrane model surface were researched at different aeration rate. The results showed that adding suspended carriers in MBR can increase the concentration of EPSS and EPSB in activated sludge mixing liquid, but the effect on EPSS and EPSB in the sludge on membrane model surface is related to aeration rate. Adding suspended carriers can increase the concentration of EPSS and EPSB in the sludge on membrane model surface at 0.10m3/h of aeration rate; the concentration of EPSS and EPSB in the sludge with suspended carriers is reduced when aeration rate is increased to 0.25m3/h. The study on the effect of aeration rate on EPS in sludge mixing liquid of MBR and in sludge on membrane model surface showed that an optimized aeration rate exists if suspended carriers are added to control MBR membrane fouling. At the optimized aeration rate, membrane fouling can be mitigated and controled effectively.

scholarly journals Characterization of the Fouling Layer on the Membrane Surface in a Membrane Bioreactor: Evolution of the Foulants’ Composition and Aggregation Ability

Membranes ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 85 ◽  
Author(s):  
Linlin Yan ◽  
Ruixue Li ◽  
Yu Song ◽  
Yanping Jia ◽  
Zheng Li ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Extracellular Dna ◽  
Transmembrane Pressure ◽  
Average Roughness ◽  
Three Stages ◽  
Fast Rise

In this study, the characteristics of membrane foulants were analyzed with regard to morphology, composition, and aggregation ability during the three stages of transmembrane pressure (TMP) development (fast–slow–fast rise in TMP) in a steady operational membrane bioreactor (MBR). The results obtained show that the fouling layer at the slow TMP-increase stage possessed a higher average roughness (71.27 nm) and increased fractal dimension (2.33), which resulted in a low membrane fouling rate (0.87 kPa/d). A higher extracellular DNA (eDNA) proportion (26.12%) in the extracellular polymeric substances (EPS) resulted in both higher zeta potential (-23.3 mV) and higher hydrophobicity (82.3%) for initial foulants, which induced and increased the protein proportion in the subsequent fouling layer (74.11%). Furthermore, the main composition of the EPS shifted from protein toward polysaccharide dominance in the final fouling layer. The aggregation test confirmed that eDNA was essential for foulant aggregation in the initial fouling layer, whereas ion interaction significantly affected foulant aggregation in the final fouling layer.

scholarly journals Pilot Study on the Combination of Different Pre-Treatments with Nanofiltration for Efficiently Restraining Membrane Fouling While Providing High-Quality Drinking Water

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 380
Author(s):  
Yan Chen ◽  
Huiping Li ◽  
Weihai Pang ◽  
Baiqin Zhou ◽  
Tian Li ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Post Treatment ◽  
Size Exclusion ◽  
Transmembrane Pressure ◽  
Feed Water ◽  
High Quality ◽  
Treated Water

Nanofiltration (NF) is a promising post-treatment technology for providing high-quality drinking water. However, membrane fouling remains a challenge to long-term NF in providing high-quality drinking water. Herein, we found that coupling pre-treatments (sand filtration (SF) and ozone–biological activated carbon (O3-BAC)) and NF is a potent tactic against membrane fouling while achieving high-quality drinking water. The pilot results showed that using SF+O3-BAC pre-treated water as the feed water resulted in a lower but a slowly rising transmembrane pressure (TMP) in NF post-treatment, whereas an opposite observation was found when using SF pre-treated water as the feed water. High-performance size-exclusion chromatography (HPSEC) and three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy determined that the O3-BAC process changed the characteristic of dissolved organic matter (DOM), probably by removing the DOM of lower apparent molecular weight (LMW) and decreasing the biodegradability of water. Moreover, amino acids and tyrosine-like substances which were significantly related to medium and small molecule organics were found as the key foulants to membrane fouling. In addition, the accumulation of powdered activated carbon in O3-BAC pre-treated water on the membrane surface could be the key reason protecting the NF membrane from fouling.

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