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 Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

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.

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.

A cost optimization study of flux and fouling rate for UF in the water industry

2008 ◽  
Vol 8 (1) ◽  
pp. 113-120 ◽  
Author(s):  
G. K. Pearce
Keyword(s):  
Membrane Fouling ◽  
Cost Optimization ◽  
Plant Size ◽  
Operating Pressure ◽  
High Flux ◽  
Chemical Cleaning ◽  
Critical Flux ◽  
Membrane Area ◽  
Optimization Study ◽  
The Relationship

Designing a commercial UF/MF system is an exercise in compromise. Selecting a high flux reduces capex by minimizing the membrane area required, but increases operating costs due to the increased chemical cleaning frequency, higher waste disposal volumes, and higher operating pressure. Most commercial systems are designed to run at fluxes significantly above the critical flux, so a degree of fouling and a reliance on chemical cleaning is inherent to the design. This paper examines the relationship between flux and membrane fouling rate through a review of experimental field data. The analysis shows that fouling rate increases exponentially with flux, with a function dependent upon the characteristics of the feed. The paper then presents the results of a cost optimization study in which Total Water Cost (TWC) is evaluated as a function of feed source and plant size for different CIP cleaning frequencies. The minimum TWC occurs in all cases for CIP frequencies of between 1/week and 1/month. Smaller plants with low fouling feeds have an optimum near 1 CIP/week using a relatively high flux design. In contrast, feeds with higher fouling propensity, and medium or large plant sizes have a TWC optimum close to 1 CIP/month, and should use a lower design flux. It is suggested that the flux corresponding to the TWC optimum should be designated the sustainable flux.

The Study of the Fluorescence In Situ Hybridization Applied in the Denitrifying Bacteria on Metal Membrane Bioreactor’s Denitrification Tank

2011 ◽  
Vol 317-319 ◽  
pp. 250-253
Author(s):  
Pan Zhang ◽  
Lei Chen
Keyword(s):  
Membrane Bioreactor ◽  
Removal Rate ◽  
Denitrifying Bacteria ◽  
Ammonia Nitrogen ◽  
Nitrifying Bacteria ◽  
Active Sludge ◽  
Metal Membrane ◽  
The Relationship ◽  
Plate Type

In order to study changes in the quantity of different denitrifying bacteria during the process of the metal membrane bioreactor, and to determine the relationship between different types of bacteria’s quantity and the treating water quality, the fluorescence in situ hybridization (FISH) dominant molecular biological technologies were used in this study to explore different denitrifying bacteria populations in the active sludge in the denitrification tank on the immersed plate-type metal membrane bioreactor. The study result implies that the addition involvement of the denitrification tank is enormous beneficial to the growth of all bacteria and nitrifying bacteria, meanwhile the removal rate of total nitrogen and ammonia nitrogen is improved as well.

Sign in / Sign up

Export Citation Format

Share Document