Identification of the effect of extracellular polymeric substances on bacterial adhesion to the membrane surface in a membrane bioreactor using Pseudomonas fluorescens

2007 ◽  
Vol 55 (1-2) ◽  
pp. 35-42 ◽  
Author(s):  
Y. Yeo ◽  
N. Jang ◽  
J. Cho ◽  
K.-S. Kim ◽  
I.S. Kim
Keyword(s):  
Pseudomonas Fluorescens ◽  
Membrane Fouling ◽  
Bacterial Adhesion ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Municipal Wastewater Treatment ◽  
Wastewater Treatment Process ◽  
Specific Cake Resistance

In a membrane bioreactor (MBR) process containing a variety of bacteria, the bacterial adhesion to the membrane surface, prior to cake formation, causes an increased filtration resistance. In this study, Pseudomonas fluorescens, commonly found in the municipal wastewater treatment process with activated sludge, was used to show the effects of extracellular polymeric substances (EPS) on bacterial adhesion to the membrane surface in the MBR. Of the various roles of EPS in promoting membrane fouling, the adhesion of bacteria to the membrane surface was calculated using the specific cake resistance (α, m/kg). Although the amount of EPS binding with bacteria was increased by the addition of Ca2 + , there was no significant effect on the bacterial growth. The results of the particle size distribution showed that the addition of Ca2 +  increased flocculation, allowing the formation of a complex with the bacteria and EPS. In order to identify the effects of the addition of Ca2 +  on the hydrophobicity, the contact angle was also measured. The result showed that the addition of Ca2 +  showed no significant differences in the hydrophobicity, even though there was an increase in flocculation. With the bacteria containing a higher EPS concentration, a higher specific cake resistance was observed. From the results of the adhesion experiment, which was conducted with various EPS levels, displayed as the COD and TOC concentration, an increased EPS concentration was shown to promote bacterial adhesion to the membrane surface.

Performance of membrane bioreactor combined with pre-coagulation/sedimentation

2004 ◽  
Vol 4 (1) ◽  
pp. 143-149 ◽  
Author(s):  
T. Itonaga ◽  
Y. Watanabe
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Term Operation ◽  
Made In

This paper deals with the performance of a hybrid membrane bioreactor (MBR) combined with pre-coagulation/sedimentation. Primary clarifier effluent in a municipal wastewater treatment plant was fed into the hybrid MBR to investigate its performance during long-term operation. Pre-coagulation/sedimentation process efficiently removed the suspended solids including organic matter and phosphorus. Comparison of the hybrid MBR and conventional MBR was made in terms of the permeate quality and membrane fouling. As the organic loading to the MBR was significantly reduced by the pre-coagulation/sedimentation, production and accumulation of extracellular polymeric substances (EPS) may be limited. Therefore, the mixed liquor viscosity in the hybrid MBR was much lower than that in the conventional MBR. These effect caused by pre-coagulation/sedimentation brought a remarkable improvement in both permeate quality and membrane permeability.

scholarly journals Membrane Fouling Monitoring in a Submerged Membrane Bioreactor

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 653
Author(s):  
Konstantinos Azis ◽  
Marianthi Malioka ◽  
Spyridon Ntougias ◽  
Paraschos Melidis
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Cross Flow ◽  
Pilot Scale ◽  
Municipal Wastewater Treatment ◽  
Membrane Performance ◽  
Conventional Activated Sludge ◽  
Major Disadvantage

Use of Membrane Bioreactor (MBR) technology for municipal wastewater treatment has been increased in recent years, as it successfully overcomes the disadvantages of the conventional activated sludge process. Membrane fouling is the major disadvantage of MBRs and leads to decreased membrane performance and expanded operational expenses. In this study, fouling was monitored in a pilot-scale submerged MBR system fed with municipal wastewater. TMP was directly measured on the membrane module during the operation. To control TMP increase owing to biosolids accumulation on membrane surface, successive backwashes and air-cross flow velocity increase were applied. These measures lowered TMP and improved flux.

scholarly journals Effects of electrochemical processes application on the modification of mixed liquor characteristics of an electro-membrane bioreactor (e-MBR)

2018 ◽  
Vol 78 (11) ◽  
pp. 2364-2373 ◽  
Author(s):  
André Aguiar Battistelli ◽  
Rayra Emanuelly da Costa ◽  
Leonardo Dalri-Cecato ◽  
Tiago José Belli ◽  
Flávio Rubens Lapolli
Keyword(s):  
Electric Field ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Municipal Wastewater Treatment ◽  
Floc Size ◽  
Mixed Liquor ◽  
Average Value ◽  
Electrochemical Processes

Abstract This study evaluated the effects of electrochemical processes on the mixed liquor characteristics of an electro-membrane bioreactor (e-MBR) applied to municipal wastewater treatment. A laboratory-scale e-MBR was assessed under two experimental runs: without the electric field (run I) and with electric field, controlled by the application of an electric current set in 10.0 A m−2 under intermittent exposure mode of 6 minutes ON/18 minutes OFF (run II). The electric field caused approximately 55% removal of both soluble microbial products (SMP) and extracellular polymeric substances (EPS), whereas the proteins/carbohydrates ratio in EPS was increased from 1.9 in the run I to 2.9 in run II, leading to an increment of flocs' hydrophobicity. Additionally, the sludge floc size average value was reduced from 42.2 μm in run I to 24.6 μm in run II, which led to a significant enhancement in the sludge settleability. As a result, the membrane fouling rate was always less than 3.80 mbar d−1 in run II, whereas in run I these values reached up to 34.7 mbar d−1. These results demonstrated that the electrochemical processes enhanced the mixed liquor filterability. Therefore, their implementation represents a great alternative to improve the operational stability of membrane bioreactors.

Correlation between membrane fouling and soluble/colloidal organic substances in membrane bioreactors for municipal wastewater treatment

2005 ◽  
Vol 51 (6-7) ◽  
pp. 1-8 ◽  
Author(s):  
B. Lesjean ◽  
S. Rosenberger ◽  
C. Laabs ◽  
M. Jekel ◽  
R. Gnirss ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Membrane Bioreactors ◽  
Size Exclusion ◽  
Water Phase ◽  
Parallel Operation ◽  
Municipal Wastewater Treatment ◽  
Operational Conditions ◽  
The Difference

Two similar membrane bioreactors of 2 m3 each were operated in parallel over two years under the same operational conditions, fed with the same municipal wastewater. The only process and operational difference between both pilot plants was the position of the denitrification zone (pre-denitrification in pilot 1 and post-denitrification in pilot 2). Despite parallel operation, the two MBRs exhibited different fouling rates and decreases in permeability. These differences could not be accounted for by MLSS concentrations, loading rates, or filtration flux. In a one-year investigation, soluble and colloidal organic material in the activated sludge of both MBR was regularly analysed by spectrophotometric and Size Exclusion Chromatography (SEC) methods. The larger organic molecules present in the sludge water phase (i.e. polysaccharides, proteins and organic colloids) originating from microbial activity (extracellular polymeric substances) were found to impact on the fouling and to explain the difference in membrane performance between the two MBR units. In both pilot plants, a linear relationship could be clearly demonstrated between the fouling rate of the membrane and the concentration of polysaccharides in the sludge water phase during a 5 month operational period at an SRT of 8 days.

Comparative study on membrane fouling between membrane-coupled moving bed biofilm reactor and conventional membrane bioreactor for municipal wastewater treatment

2013 ◽  
Vol 69 (5) ◽  
pp. 1021-1027 ◽  
Author(s):  
W. Yang ◽  
W. Syed ◽  
H. Zhou
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Biofilm Reactor ◽  
Municipal Wastewater Treatment ◽  
Moving Bed Biofilm Reactor ◽  
Reactor Unit ◽  
Polyaluminum Chloride ◽  
Moving Bed

This study compared the performance between membrane-coupled moving bed biofilm reactor (M-MBBR) and a conventional membrane bioreactor (MBR) in parallel. Extensive tests were conducted in three pilot-scale experimental units over 6 months. Emphasis was placed on the factors that would affect the performance of membrane filtration. The results showed that the concentrations of soluble microbial product (SMP), colloidal total organic carbon and transparent exopolymer particles in the M-MBBR systems were not significantly different from those in the control MBR system. However, the fouling rates were much higher in the M-MBBR systems as compared to the conventional MBR systems. This indicates membrane fouling potential was related not only to the concentration of SMP, but also to their sources and characteristics. The addition of polyaluminum chloride could reduce the fouling rate of the moving bed biofilm reactor unit by 56.4–84.5% at various membrane fluxes.

scholarly journals Biomass Characteristics and Their Effect on Membrane Bioreactor Fouling

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2867 ◽  
Author(s):  
Petros K. Gkotsis ◽  
Anastasios I. Zouboulis
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Soluble Microbial Products ◽  
Gelling Properties ◽  
Microbial Products ◽  
Soluble Part

Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMPc) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF100, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.

Impact of chemical cleaning and air-sparging on the critical and sustainable flux in a flat sheet membrane bioreactor for municipal wastewater treatment

2008 ◽  
Vol 57 (12) ◽  
pp. 1873-1879 ◽  
Author(s):  
G. Guglielmi ◽  
D. Chiarani ◽  
D. P. Saroj ◽  
G. Andreottola
Keyword(s):  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Municipal Wastewater Treatment ◽  
Chemical Cleaning ◽  
Critical Flux ◽  
Submerged Membrane Bioreactor ◽  
Flat Sheet ◽  
Exponential Trend ◽  
Flat Sheet Membrane

The paper discusses the experimental optimisation of both chemical and mechanical cleaning procedures for a flat-sheet submerged membrane bioreactor fed with municipal wastewater. Fouling was evaluated by means of the critical flux concept, which was experimentally measured by short-term flux-stepping tests. By keeping constant most important parameters of the biological process (MLSS, sludge age), two different chemical cleaning protocols (2,000 mg L−1 NaOCl and 200 mg L−1 NaOCl) were applied with different frequency and, after approximately 9 months of operation, the criticality threshold was determined under different values of SADm (specific aeration demand per unit of membrane surface area). The weaker and more frequent chemical cleaning regime (200 mg L−1, monthly) proved much more effective than the stronger and less frequent strategy (2,000 mg L−1, once every three months). The improvement of performances was quantified by two TMP-based parameters, the fouling rate and the ΔTMP (difference between TMP values during the increasing and decreasing phase of hysteresis). The best performing configuration was then checked over a longer period by running four long-term trials showing an exponential trend of the sub-critical fouling rate with the imposed flux.

scholarly journals Impacts of the specific cake resistance on mbr fouling for wastewater treatment

2021 ◽  
Vol 72 (7) ◽  
pp. 841-849
Author(s):  
Guigui Christelle ◽  
Nga Vu Thi Thu
Keyword(s):  
Wastewater Treatment ◽  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Peak Height ◽  
Transmembrane Pressure ◽  
Strongly Correlated ◽  
Municipal Wastewater Treatment ◽  
Fouling Resistance ◽  
Sustainable Operation ◽  
Specific Cake Resistance

Membrane bioreactor (MBR) has been increasingly used for municipal wastewater treatment and reuse due to its good effluent quality. However, membrane fouling remains the major limitation of MBR. Understanding fouling is still a key issue for a more sustainable operation of MBRs. Thus, this research presents the influence of specific cake resistance (α) on the fouling propensity in the MBR. Correlation between α value with fouling resistance (Rf), fouling rate (dTMP/dt), especially of peak height 100-1000 kDa protein-like SMPs was investigated. The result reported that the α value was strongly correlated with the dTMP/dt in the MBR (R2 value of close to 1). In this study, however, there is an obvious discrepancy between the fouling resistance calculated from the resistance in the series model and the α value in the supernatant filtration. These observations demonstrated that the fouling propensities of the membrane could be monitored by the transmembrane pressure and the fouling characteristics, include fouling resistance and specific cake resistance in the filtration cell.

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