Effect of Extracellular Polymeric Substances on Operation of Membrane Bioreactor

2012 ◽  
Vol 549 ◽  
pp. 491-495
Author(s):  
Wan You Zhang ◽  
Xin Yan Wang ◽  
Li Juan Xi
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Membrane Resistance ◽  
Volume Index ◽  
Direct Influence ◽  
Sludge Volume Index ◽  
Simple Method ◽  
Modified Fouling Index ◽  
The Relationship

In order to study the relationship between extracellular polymeric substances (EPS) and membrane fouling, the effect of extracellular polymeric substances (EPS) on the operation of membrane bioreactor (MBR) was investigated in this paper. The operation of membrane was analyzed by evaluating sludge volume index (SVI), modified fouling index (MFI), and membrane resistance (Rt), respectively. The results showed that SVI, MFI, and Rt increased with the accumulation of EPS, and membrane fouling aggravated with the increase of EPS, this illustrated that the content of EPS had a direct influence on SVI, MFI, Rt and membrane fouling. The consequences could offer a simple method to monitor the concentration of EPS by analyzing SVI, MFI, or Rt.

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.

The Effect of Media Fill Ratio on Membrane Fouling in Moving Bed Bioreactors-Membrane Bioreactor

2013 ◽  
Vol 726-731 ◽  
pp. 470-473 ◽  
Author(s):  
Liang Duan ◽  
Yong Hui Song ◽  
Wei Jiang ◽  
Slawomir W. Hermanowicz
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Major Fraction ◽  
Fill Ratio ◽  
Moving Bed ◽  
Large Molecular Weight ◽  
High Fraction ◽  
Microbial Products ◽  
Modified Fouling Index

This research investigated the effect of media fill ratio on membrane fouling in moving bed bioreactors-membrane bioreactor. The results shown the high removal of ammonia and COD, despite the membrane fouling conditions were really different in two bioreactors. The total modified fouling index (MFI) of IFAS 3000 was three times than MFI of IFAS 1500, and the soluble microbial products (SMP) present in the mixed liquor played an important role in the membrane fouling. No more correlation was found between the extracellular polymeric substances (EPS) concentration and fouling, and the average SMP of IFAS 3000 was higher than IFAS 1500. The carbohydrate of SMP occupied high fraction in all reactors. Large molecular weight (MW) components constituted the major fraction of EPS and SMP. The results indicated that higher media fill ratio can decrease membrane fouling effectively.

Effects of Sludge Retention Time on the Characteristics of Mixed Liquor and Membrane Fouling in Membrane Bioreactor

2010 ◽  
Vol 113-116 ◽  
pp. 2057-2061 ◽  
Author(s):  
Zhan Ping Cao ◽  
Jing Li Zhang ◽  
Hong Wei Zhang
Keyword(s):  
Zeta Potential ◽  
Retention Time ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Volume Index ◽  
Bacterial Surface ◽  
Sludge Retention Time ◽  
Dominant Bacteria

In the membrane bioreactor (MBR) treating municipal wastewater, the effect of sludge retention time (SRT) on the contents of the extracellular polymeric substances (EPS), tightly bound EPS (TB) and loosely bound EPS (LB) and the ratios of protein and polysaccharide in TB and LB was studied. With the extension of SRT the EPS increased and the ratios of protein and polysaccharide in TB and LB changed. The above changes influenced the charge distribution of bacterial surface, increased the proportion of hydrophilicity and hydrophobicity on the bacterial surface, changed the bacteria from the instable (R-type) to the stable (S-type), decreased the Zeta potential and increased the values of sludge volume index (SVI). The correlation analysis for the main parameters of fouling resistance was performed by SPSS software, and it was found that the correlation coefficient (rp) was -0.818 for Zeta potential, 0.853 for the content of suspended solids in supernatant and 0.832 for relative hydrophobicity, respectively. SRT of the MBR should be controlled below 120 times of the minimum generation-time of dominant bacteria considering the membrane fouling and sludge characteristics.

Investigation of long-term operation and biomass activity in a membrane bioreactor system

2011 ◽  
Vol 63 (9) ◽  
pp. 1906-1912 ◽  
Author(s):  
Simos Malamis ◽  
Andreas Andreadakis ◽  
Daniel Mamais ◽  
Constantinos Noutsopoulos
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Operating Conditions ◽  
Term Operation ◽  
Solids Retention ◽  
Biomass Activity ◽  
Long Term Performance ◽  
Term Performance

The aim of this work was to evaluate the long-term performance of a Membrane Bioreactor (MBR) that operated continuously for 2.5 years and to assess membrane fouling and biomass activity under various operating conditions. Furthermore, a method for the characterisation of influent wastewater was developed based on its separation into various fractions. The MBR system operated at the solids retention times (SRT) of 10, 15, 20 and 33 days. The increase of SRT resulted in a decrease of the fouling rate associated with the reduction of extracellular polymeric substances. Moreover, the SRT increase resulted in a significant reduction of the Oxygen Uptake Rate (OUR) due to the lower availability of substrate and in a notable decrease of the maximum OUR since high SRT allowed the development of slower growing microorganisms. Biomass consisted of small flocs due to extensive deflocculation caused by intense aeration. Finally, the method developed for wastewater characterisation is straightforward and less time consuming than the usual method that is employed.

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 Swine manure treatment by anaerobic membrane bioreactor with carbon, nitrogen and phosphorus recovery

2017 ◽  
Vol 76 (8) ◽  
pp. 1939-1949 ◽  
Author(s):  
Fan Bu ◽  
Shiyun Du ◽  
Li Xie ◽  
Rong Cao ◽  
Qi Zhou
Keyword(s):  
Relaxation Rate ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Swine Manure ◽  
Phosphorus Recovery ◽  
Methane Yield ◽  
Continuous Stirred Tank Reactor ◽  
Chemical Cleaning ◽  
Anaerobic Membrane Bioreactor

Swine manure wastewater was treated in an anaerobic membrane bioreactor (AnMBR) that combined a continuous stirred tank reactor (CSTR) and a hollow-fiber ultrafiltration membrane, and the feasibility of ammonia and phosphorus recovery in the permeate was investigated. The AnMBR system was operated steadily with a high mixed liquor suspended solids (MLSS) concentration of 32.32 ± 6.24 g/L for 120 days, achieving an average methane yield of 280 mL/gVSadded and total chemical oxygen demand removal efficiency of 96%. The methane yield of the AnMBR is 83% higher than that of the single CSTR. The membrane fouling mechanism was examined, and MLSS and the polysaccharide contents of the extracellular polymeric substances were found to be the direct causes of membrane fouling. The effects of the permeation/relaxation rate and physical, chemical cleaning on membrane fouling were assessed for membrane fouling control, and results showed that a decrease in the permeation/relaxation rate together with chemical cleaning effectively reduced membrane fouling. In addition, a crystallization process was used for ammonia and phosphorus recovery from the permeate, and pH 9 was the optimal condition for struvite formation. The study has an instructive significance to the industrial applications of AnMBRs in treating high strength wastewater with nutrient recovery.

Electrically enhanced MBR system for total nutrient removal in remote northern applications

2012 ◽  
Vol 65 (4) ◽  
pp. 737-742 ◽  
Author(s):  
V. Wei ◽  
M. Elektorowicz ◽  
J. A. Oleszkiewicz
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Climatic Conditions ◽  
Transmembrane Pressure ◽  
Treatment Technology ◽  
Electrically Enhanced ◽  
P Removal

Thousands of sparsely populated communities scatter in the remote areas of northern Canada. It is economically preferable to adopt the decentralized systems to treat the domestic wastewater because of the vast human inhabitant distribution and cold climatic conditions. Electro-technologies such as electrofiltration, elctrofloatation, electrocoagulation and electrokinetic separation have been applied in water and conventional wastewater treatment for decades due to the minimum requirements of chemicals as well as ease of operation. The membrane bioreactor (MBR) is gaining popularity in recent years as an alternative water/wastewater treatment technology. However, few studies have been conducted to hyphenate these two technologies. The purpose of this work is to design a novel electrically enhanced membrane bioreactor (EMBR) as an alternative decentralized wastewater treatment system with improved nutrient removal and reduced membrane fouling. Two identical submerged membranes (GE ZW-1 hollow fiber module) were used for the experiment, with one as a control. The EMBR and control MBR were operated for 4 months at room temperature (20 ± 2 °C) with synthetic feed and 2 months at 10 °C with real sewage. The following results were observed: (1) the transmembrane pressure (TMP) increased significantly more slowly in the EMBR and the interval between the cleaning cycles of the EMBR increased at least twice; (2) the dissolved chemical oxygen demand (COD) or total organic carbon (TOC) in the EMBR biomass was reduced from 30 to 51%, correspondingly, concentrations of the extracellular polymeric substances (EPS), the major suspicious membrane foulants, decreased by 26–46% in the EMBR; (3) both control and EMBR removed >99% of ammonium-N and >95% of dissolved COD, in addition, ortho-P removal in the EMBR was >90%, compared with 47–61% of ortho-P removal in the MBR; and (4) the advantage of the EMBR over the conventional MBR in terms of membrane fouling retardation and phosphorus removal was further demonstrated at an operating temperature of 10 °C when fed with real sewage. The EMBR system has the potential for highly automated control and minimal maintenance, which is particularly suitable for remote northern applications.

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.

scholarly journals Treatment of Septic Tank Effluent by Membrane Bioreactor: A Laboratory–scale Feasibility Study

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
C–Y. Chang ◽  
Roger Ben Aim ◽  
S. Vigneswaran ◽  
J–S. Chang ◽  
S–L. Chen
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Laboratory Scale ◽  
Septic Tank ◽  
Term Operation ◽  
Water Cleaning ◽  
Septic Tank Effluent

A laboratory scale membrane bioreactor (MBR) fed on real septic tank effluent was studied at different levels of alkalinity (0, 250 and 500 mg NaHCO3/L addition) and sludge retention time (SRT, complete sludge retention, 10 and 20 days). A long–term operation of 267 days was divided into 5 stages to examine the SRT and alkalinity influences on parameters related to nitrification, chemical oxygen demand (COD) removal, extracellular polymeric substances (EPS) production and membrane cleaning. The results of the study showed that the removals of TCOD, SCOD and NH4+–N varied between 86–94%, 71–86%, and 70–94%, respectively. Appropriate alkalinity supplement and SRT control can enhance the COD removal and nitrification. Irreversible membrane fouling occurred fast and water cleaning for the improvement of filtration capacity was ineffective. The results also revealed that the rejection of EPS played a major role both in the enhancement of removal efficiency as well as the increase of filtration resistance during the operation.

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