Characteristics of membrane fouling in submerged membrane bioreactor under sub-critical flux operation

2008 ◽  
Vol 57 (4) ◽  
pp. 601-605 ◽  
Author(s):  
Y. C. Su ◽  
C. P. Huang ◽  
H. C. Lee ◽  
Jill R. Pan
Keyword(s):  
Shear Stress ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Permeate Flux ◽  
Membrane Unit ◽  
Widespread Application ◽  
Critical Flux ◽  
Membrane Cleaning ◽  
Close Link ◽  
Novel Technologies

Recently, the membrane bioreactor (MBR) process has become one of the novel technologies to enhance the performance of biological treatment of wastewater. Membrane bioreactor process uses the membrane unit to replace a sediment tank, and this can greatly enhance treatment performance. However, membrane fouling in MBR restricts its widespread application because it leads to permeate flux decline, making more frequent membrane cleaning and replacement necessary, which then increases operating and maintenance costs. This study investigated the sludge characteristics in membrane fouling under sub-critical flux operation and also assessed the effect of shear stress on membrane fouling. Membrane fouling was slow under sub-critical flux operation. However, as filamentous microbes became dominant in the reactor, membrane fouling increased dramatically due to the increased viscosity and polysaccharides. A close link was found between membrane fouling and the amount of polysaccharides in soluble EPS. The predominant resistance was the cake resistance which could be minimized by increasing the shear stress. However, the resistance of colloids and solutes was not apparently reduced by increasing shear stress. Therefore, smaller particles such as macromolecules (e.g. polysaccharides) may play an important role in membrane fouling under sub-critical flux operation.

Pulse shear stress for anaerobic membrane bioreactor fouling control

2011 ◽  
Vol 64 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Jixiang Yang ◽  
Henri Spanjers ◽  
Jules B. van Lier
Keyword(s):  
Shear Stress ◽  
Membrane Fouling ◽  
Slug Flow ◽  
Membrane Bioreactor ◽  
Particle Diameter ◽  
Membrane Unit ◽  
Flux Flow ◽  
Anaerobic Membrane Bioreactor ◽  
Tubular Membrane ◽  
Fouling Control

Increase of shear stress at membrane surfaces is a generally applied strategy to minimize membrane fouling. It has been reported that a two-phase flow, better known as slug flow, is an effective way to increase shear stress. Hence, slug flow was introduced into an anaerobic membrane bioreactor for membrane fouling control. Anaerobic suspended sludge was cultured in an anaerobic membrane bioreactor (AMBR) operated with a side stream inside-out tubular membrane unit applying sustainable flux flow regimes. The averaged particle diameter decreased from 20 to 5 μm during operation of the AMBR. However, the COD removal efficiency did not show any significant deterioration, whereas the specific methanogenic activity (SMA) increased from 0.16 to 0.41 g COD/g VSS/day. Nevertheless, the imposed gas slug appeared to be insufficient for adequate fouling control, resulting in rapidly increasing trans membrane pressures (TMP) operating at a flux exceeding 16 L/m2/h. Addition of powdered activated carbon (PAC) enhanced the effect of slug flow on membrane fouling. However, the combined effect was still considered as not being significant. The tubular membrane was subsequently equipped with inert inserts for creating a locally increased shear stress for enhanced fouling control. Results show an increase in the membrane flux from 16 L/m2/h to 34 L/m2/h after the inserts were mounted in the membrane tube.

Metal Ions on the Membrane Bioreactor in the Slow Progress of Membrane Fouling Studies

2014 ◽  
Vol 926-930 ◽  
pp. 158-161
Author(s):  
Wan You Zhang ◽  
Sheng Chao Ji ◽  
Hai Feng Zhang ◽  
Xi Xin Zhang
Keyword(s):  
Metal Ions ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Future Research ◽  
Widespread Application ◽  
Slow Progress ◽  
Flocculation Process

Membrane bioreactor (MBR) has developed rapidly in recent years; however, the membrane fouling problems are affecting its further widespread application. This paper discusses the role of metal ions in the mixture in the mechanism; also on the high-priced metal ions coexist in the mixture when the effects of biological flocculation process; finally, the direction of future research in this area are summarized.

Evaluation of a hybrid vertical membrane bioreactor (HVMBR) for wastewater treatment

2012 ◽  
Vol 65 (6) ◽  
pp. 1109-1115 ◽  
Author(s):  
L. Rodríguez-Hernández ◽  
A. L. Esteban-García ◽  
A. Lobo ◽  
J. Temprano ◽  
C. Álvaro ◽  
...  
Keyword(s):  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Fixed Bed ◽  
Bulk Liquid ◽  
Membrane Unit ◽  
Membrane Cleaning ◽  
Biofilm Thickness ◽  
Support Medium ◽  
Removal Efficiencies ◽  
Solids Removal

A new hybrid membrane bioreactor (HMBR) has been developed to obtain a compact module, with a small footprint and low requirement for aeration. The aim of this research was to assess its performance. The system consists of a single vertical reactor with a filtration membrane unit and, above this, a sponge fixed bed as support medium. The aeration system is located under the membrane unit, allowing for membrane cleaning, oxygenation, biofilm thickness control and bulk liquid mixing. Operated under continuous aeration, a bench-scale reactor (70 L) was fed with pre-treated, raw (unsettled) municipal wastewater. BOD5 and suspended solids removal efficiencies (96 and 99% respectively) were comparable to those obtained with other membrane bioreactors (MBRs). Total nitrogen removal efficiencies of 80% were achieved, which is better than those obtained in other HMBRs and similar to the values reached using more complex MBRs with extra anoxic tanks, intermittent aeration or internal deflectors.

scholarly journals Effects of tannic acid on membrane fouling and membrane cleaning in forward osmosis

2017 ◽  
Vol 76 (11) ◽  
pp. 3160-3170 ◽  
Author(s):  
Wanzhu Zhang ◽  
Lin Wang ◽  
Bingzhi Dong
Keyword(s):  
Tannic Acid ◽  
Calcium Ions ◽  
Membrane Fouling ◽  
Driving Forces ◽  
Forward Osmosis ◽  
Operating Conditions ◽  
Permeate Flux ◽  
Membrane Cleaning ◽  
Draw Solution ◽  
Cleaning Methods

Abstract The fouling behavior during forward osmosis (FO) was investigated. Tannic acid was used as a model organic foulant for natural organic matter analysis since the main characteristics are similar, and calcium ions were added at different concentrations to explore the anti-pollution capability of FO membranes. The initial permeate flux and calcium ions strength were varied in different operating conditions to describe membrane fouling with membrane cleaning methods. The observed flux decline in FO changed dramatically with the type of foulant and the type of draw solution used to provide the osmotic driving force. Calcium ions aggravated membrane fouling and decreased transmembrane flux. Membrane cleaning methods included physical and physicochemical approaches, and there was no obvious difference among the typical cleaning methods (i.e., membrane flushing with different types of cleaning fluids at various crossflow velocities and backwashing with varying osmotic driving forces) with respect to flux recovery. Ultrasonic cleaning damaged the membrane structure and decreased permeate flux, and reverse diffusion of salt from the draw solution to the feed side accelerated after cleaning.

Monitoring of transparent exopolymer particles (TEP) in a membrane bioreactor (MBR) and correlation with other fouling indicators

2008 ◽  
Vol 58 (10) ◽  
pp. 1903-1909 ◽  
Author(s):  
T. de la Torre ◽  
B. Lesjean ◽  
A. Drews ◽  
M. Kraume
Keyword(s):  
Linear Correlation ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Systems ◽  
Transparent Exopolymer Particles ◽  
Critical Flux ◽  
Capillary Suction ◽  
Acidic Fraction ◽  
The Relationship

The occurrence of Transparent Exopolymer Particles (TEP), an acidic fraction of polysaccharides, was monitored for more than six months in the activated sludge of three MBR units, and the relationship between TEP and other fouling indicators was studied. These compounds consist mainly of exopolysaccharides of a sticky nature, a characteristic which makes them a group of interesting substances in processes like sedimentation, flocculation and membrane fouling. The relationship between capillary suction time (CST) and polysaccharides (PS) was linear for the three tested sludges, although the correlation with TEP concentrations was stronger. A slight linear correlation of both TEP and PS was found with the critical flux (CF) measured with a small filtration test cell, which was submerged in the membrane tank to assess the filterability performance of the sludge in situ. However, the correlation CF-PS was clearer. The relationship between TEP, polysaccharides and sludge filterability highlights the potential of this parameter for the monitoring of membrane systems.

A real trial of a long-term non-fouling membrane bioreactor for saline sewage treatment

2011 ◽  
Vol 63 (7) ◽  
pp. 1519-1523 ◽  
Author(s):  
Peng Bai ◽  
Jin Wang ◽  
Guang-Hao Chen
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Pilot Trial ◽  
Sewage Treatment ◽  
Power Source ◽  
Permeate Flux ◽  
Mixing Condition ◽  
Water Ratio

This paper reports on a pilot trial of a novel MBR developed with coarse-pore membrane module by the authors. The plant was operated for 370 days with up to 7 m3/d raw saline sewage after 3-mm screening. The plant performed successfully without membrane fouling for 270 days except an accidental power source failure for 30 h, during which membrane was fouled under no aeration and mixing condition. EPS increases in both the reactor and the bio-cake on the membrane surface explained this fouling. The average TSS, COD and TKN removal efficiency were 92, 90, and 93%, respectively, under a high effective permeate flux of 4.8 m/d and a low air-to-water ratio of 15.

scholarly journals Design, construction and evaluation OFAN experimental ceramic membrane facility with investigation into fouling control

2021 ◽  
Author(s):  
Sarah Shim
Keyword(s):  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Ceramic Membranes ◽  
Membrane Unit ◽  
Membrane Cleaning ◽  
Fouling Control ◽  
Solids Concentration ◽  
Start Up ◽  
Water And Wastewater ◽  
Design Construction

During the past decade, the growth in membrane research and technology has advanced and multiplied in usage for many industries including water and wastewater. A major limitation of the application is due to membrane fouling. In this work, the construction, start-up calibration and testing of a membrane unit, as well as an examination into the fouling and cleaning aspect of the ceramic membranes are investigated. An aqueous solution containing precipitate is fed to the unit in order to observe fouling behaviour. Effluent wastewater from a bioreactor, CUBEN, is also tested with the unit and membrane cleaning is performed using various chemical agents. For both chemically enhanced backwash (CEB) and membrane soaking, hydrochloric acid cleaning agent «1 %w) produces best flux recoveries of 72.7% and 82%, respectively. All permeate effluent analysis, resulted in a suspended solids concentration <3 mgIL and turbidities. < 1 NTU, which both meet Ontario regulation limits.

scholarly journals Design, construction and evaluation OFAN experimental ceramic membrane facility with investigation into fouling control

2021 ◽  
Author(s):  
Sarah Shim
Keyword(s):  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Ceramic Membranes ◽  
Membrane Unit ◽  
Membrane Cleaning ◽  
Fouling Control ◽  
Solids Concentration ◽  
Start Up ◽  
Water And Wastewater ◽  
Design Construction

During the past decade, the growth in membrane research and technology has advanced and multiplied in usage for many industries including water and wastewater. A major limitation of the application is due to membrane fouling. In this work, the construction, start-up calibration and testing of a membrane unit, as well as an examination into the fouling and cleaning aspect of the ceramic membranes are investigated. An aqueous solution containing precipitate is fed to the unit in order to observe fouling behaviour. Effluent wastewater from a bioreactor, CUBEN, is also tested with the unit and membrane cleaning is performed using various chemical agents. For both chemically enhanced backwash (CEB) and membrane soaking, hydrochloric acid cleaning agent «1 %w) produces best flux recoveries of 72.7% and 82%, respectively. All permeate effluent analysis, resulted in a suspended solids concentration <3 mgIL and turbidities. < 1 NTU, which both meet Ontario regulation limits.

scholarly journals Enhanced Removal of Organic Pollutants and Reactive Dye in Polyethersulfone Submerged Membrane Bioreactor (PES-SMBR) for Textile Wastewater

2021 ◽  
Vol 16 (1) ◽  
pp. 329-341
Author(s):  
Tukaram P. Chavan ◽  
Ganpat B. More ◽  
Sanjaykumar R. Thorat
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Textile Wastewater ◽  
Pilot Scale ◽  
Reactive Dye ◽  
Hollow Fibre ◽  
Flow Mode ◽  
Permeate Flux ◽  
Chemical Cleaning ◽  
Submerged Membrane Bioreactor

The present investigation was carried out to assess the operation of a pilot-scale submerged membrane bioreactor (SMBR) for the treatment of reactive dye and textile wastewater. The operation of SMBR model was conducted by using a polyethersulfone (PES) hollow fibre membrane with continuous flow mode at different HRTs at 8, 6 and 4 h, for 90 days. During the entire operation, the average permeate flux, TMP, F/M ratio and OLR was found to be 19 (L/m²/h), 2.6 (psi), 0.10 (g BOD/(g MLSS•d) and 0.89 (kg BOD/m³.d), respectively. The variations in the permeate flux, TMP, F/M ratio and OLR have not adversely effects on the operation of the SMBR model. Throughout the entire operation, despite the TP, TDS and conductivity, the high amount of COD (82%), BOD (86%), NO3-N (79%), TSS (98%), turbidity (97%) and colour (79%), removal was achieved. The permeate flux was declined by membrane fouling and it was recovered by chemical cleaning as well as regular backwashing during the entire operation. The results obtained from the study concluded that the hollow fibre ultrafiltration polyethersulfone (PES) membrane shows good performance while treating textile wastewater along with reactive dye solution.

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