Effect of dead cells on biofouling in the reverse osmosis process

2013 ◽  
Vol 13 (5) ◽  
pp. 1396-1401
Author(s):  
Myung Seop Shin ◽  
Lan Hee Kim ◽  
Sung-Jo Kim ◽  
Chang-Min Kim ◽  
Kyu-Jung Chae ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Live Cells ◽  
Feed Water ◽  
Fouling Control ◽  
Flux Decline ◽  
Low Concentrations ◽  
Plate Counts ◽  
Heterotrophic Plate Counts

Biofilm formation in membrane processes causes a flux decline, pressure drop increase, and other adverse effects. Understanding the mechanisms of fouling, control, and cleaning are important in order to resolve fouling problems. In this paper, the effect of cell viability on biofouling was studied via a feed water analysis and membrane autopsy. Pseudomonas aeruginosa PAO1 was used as the model bacteria. Biofouling tests were divided into two parts: live cells and dead cells (autoclaved cells). The feed water was periodically collected every 3 h to analyze the total direct counts (TDCs), heterotrophic plate counts (HPCs), and extracellular polymeric substances (EPS). A membrane autopsy was performed to characterize the fouled membrane through TDCs and EPS. When dead cells were inoculated into the feed water, low concentrations of TDCs and EPS were measured in both the feed water and fouled membrane. As a result, it was determined that initial flux decline by biofouling can be reduced if feedwater is disinfected before the reverse osmosis process.

scholarly journals Membrane Fouling and Chemical Cleaning in Three Full-Scale Reverse Osmosis Plants Producing Demineralized Water

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Florian Beyer ◽  
Judita Laurinonyte ◽  
Arie Zwijnenburg ◽  
Alfons J. M. Stams ◽  
Caroline M. Plugge
Keyword(s):  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Full Scale ◽  
Feed Water ◽  
Chemical Cleaning ◽  
Laboratory Setup ◽  
Plant Chemical ◽  
Plate Counts ◽  
Cleaning Procedures ◽  
Heterotrophic Plate Counts

Membrane fouling and cleaning were studied in three reverse osmosis (RO) plants. Feed water was secondary wastewater effluent, river water, and surface water. Membrane autopsies were used for fouling characterization. Fouling layer measurements included total organic carbon (TOC), adenosine triphosphate, polysaccharides, proteins, and heterotrophic plate counts. In all locations, membrane and spacer fouling was (bio)organic. Plant chemical cleaning efficiencies were evaluated from full-scale operational data and cleaning trials in a laboratory setup. Standard cleaning procedures were compared to two cleaning procedures specifically adapted to treat (bio)organic fouling using commercial blend cleaners (mixtures of active substances). The three RO plants were impacted by irreversible foulants causing permanently decreased performance in normalized pressure drop and water permeability even after thorough chemical cleaning. The standard plant and adapted cleaning procedures reduced the TOC by 45% on average, with a maximum of ~80%. In general, around 20% higher biomass removal could be achieved with adapted procedure I compared to adapted procedure II. TOC measurements and SEM showed that none of cleaning procedures applied could remove foulants completely from the membrane elements. This study underlines the need for novel cleaning approaches targeting resistant foulants, as none of the procedures applied resulted in highly effective membrane regeneration.

scholarly journals Inhibitory Effect of Vanillin on Biofilm Formation by Multi-Species Wastewater Culture

2020 ◽  
Vol 23 (4) ◽  
pp. 274-279
Author(s):  
Xiurong Si ◽  
Ding Ding ◽  
Jianhua Zhou ◽  
Zhangwei Cao
Keyword(s):  
Membrane Fouling ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Inhibitory Effect ◽  
Inhibition Rate ◽  
Microbial Adhesion ◽  
Fouling Control ◽  
Microfluidic Chamber ◽  
Research Findings ◽  
Static Conditions

This paper mainly investigates the inhibitory effect and mechanism of vanillin on mixed-culture biofilm formation, and discusses the feasibility of controlling membrane fouling with vanillin. The biofilms were cultured under static conditions and a microfluidic chamber, respectively. The results show that vanillin can effectively inhibit the microbial adhesion and biofilm formation; the inhibition rate increases with the vanillin concentration. After 12h treatment with 300mg/L vanillin, the inhibition rate of biofilm formation reached 85.34%. Besides, vanillin can mitigate bacterial adhesion by reducing the microbial secretion of exoprotein and exopolysaccharide, exhibit an inhibitory effect on the expression of N-acyl-l-homoserine lactones (AHLs), but had no effect on environmental deoxyribonucleic acid (eDNA). After being treated with 300mg/L vanillin, exoprotein, exopolysaccharide and AHLs decreased by 28.48%, 17.23% and 46.64%, respectively. Furthermore, there is a positive correlation between the AHLs and the content of extracellular polymeric substances (EPSs); the AHLs-mediated quorum sensing (QS) might be related to microbial adhesion through the regulation of EPS. Finally, vanillin has a great potential in membrane fouling control. The research findings provide a good reference for biofilm control in water purification and wastewater treatment systems.

Biofilm formation in drinking water affected by low concentrations of phosphorus

2002 ◽  
Vol 48 (6) ◽  
pp. 494-499 ◽  
Author(s):  
Markku J Lehtola ◽  
Ilkka T Miettinen ◽  
Pertti J Martikainen
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Microbial Growth ◽  
Available Phosphorus ◽  
Phosphorus Addition ◽  
Drinking Waters ◽  
Low Concentrations ◽  
Geographical Regions ◽  
Plate Counts ◽  
Heterotrophic Plate Counts

There are geographical regions where microbial growth in drinking waters is limited by phosphorus instead of organic carbon. In these drinking waters even a low amount of phosphorus can strongly enhance microbial growth. The formation of biofilm can be limited by low availability of phosphorus in drinking waters with low content of phosphorus. The formation of biofilms on polyvinyl chloride plates was studied in laboratory experiments with water containing 48 μg/L assimilable organic carbon and 0.19 μg/L microbially available phosphorus. We found that low additions of phosphate (1–5 μg/L PO43–-P) to water increased microbial growth in the water and in the biofilm. The effect of phosphorus on microbial growth could be detected by determining either the microbial cell production or the content of ATP in biofilms. Also, in steady-state biofilms, microbial concentrations were higher with phosphorus addition as enumerated by heterotrophic plate counts on R2A-agar and acridine orange direct counting. This work confirms the earlier findings of the importance of phosphorus for microbial growth in humic-rich drinking waters.Key words: biofilm, drinking water, microbes, phosphorus.

scholarly journals Physicochemical Properties of Extracellular Polymeric Substances Produced by Three Bacterial Isolates From Biofouled Reverse Osmosis Membranes

2021 ◽  
Vol 12 ◽  
Author(s):  
Zahid Ur Rehman ◽  
Johannes S. Vrouwenvelder ◽  
Pascal Saikaly
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
Reverse Osmosis ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Nmr Analysis ◽  
Bacterial Strains ◽  
H Nmr ◽  
Ro Membrane ◽  
C Nmr

This work describes the chemical composition of extracellular polymeric substances (EPS) produced by three bacteria (RO1, RO2, and RO3) isolated from a biofouled reverse osmosis (RO) membrane. We isolated pure cultures of three bacterial strains from a 7-year-old biofouled RO module that was used in a full-scale seawater treatment plant. All the bacterial strains showed similar growth rates, biofilm formation, and produced similar quantities of proteins and polysaccharides. The gel permeation chromatography showed that the EPS produced by all the strains has a high molecular weight; however, the EPS produced by strains RO1 and RO3 showed the highest molecular weight. Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance (1H NMR), and Carbon NMR (13C NMR) were used for a detailed characterization of the EPS. These physicochemical analyses allowed us to identify features of EPS that are important for biofilm formation. FTIR analysis indicated the presence of α-1,4 glycosidic linkages (920 cm–1) and amide II (1,550 cm–1) in the EPS, the presence of which has been correlated with the fouling potential of bacteria. The presence of α-glycoside linkages was further confirmed by 13C NMR analysis. The 13C NMR analysis also showed that the EPS produced by these bacteria is chemically similar to foulants obtained from biofouled RO membranes in previous studies. Therefore, our results support the hypothesis that the majority of substances that cause fouling on RO membranes originate from bacteria. Investigation using 1H NMR showed that the EPS contained a high abundance of hydrophobic compounds, and these compounds can lead to flux decline in the membrane processes. Genome sequencing of the isolates showed that they represent novel species of bacteria belonging to the genus Bacillus. Examination of genomes showed that these bacteria carry carbohydrates-active enzymes that play a role in the production of polysaccharides. Further genomic studies allowed us to identify proteins involved in the biosynthesis of EPS and flagella involved in biofilm formation. These analyses provide a glimpse into the physicochemical properties of EPS found on the RO membrane. This knowledge can be useful in the rational design of biofilm control treatments for the RO membrane.

Bacterial colonization of domestic reverse-osmosis water filtration units

1989 ◽  
Vol 35 (11) ◽  
pp. 1065-1067 ◽  
Author(s):  
Pierre Payment
Keyword(s):  
Drinking Water ◽  
Reverse Osmosis ◽  
Heterotrophic Bacteria ◽  
Bacterial Colonization ◽  
Water Filtration ◽  
Water Reservoirs ◽  
Colony Forming Units ◽  
Plate Counts ◽  
Bacterial Content ◽  
Heterotrophic Plate Counts

We have analyzed the bacterial content of water from the reservoirs of 300 reverse-osmosis units installed in households. The heterotrophic plate counts on R2A medium (20 and 35 °C) ranged from 0 to 107 colony forming units per millilitre (cfu/mL). Most reservoirs contained water with bacterial counts between 104 and 105 cfu/mL. The bacteria identified were Pseudomonas (not aeruginosa), Alcaligenes or Moraxella, Acinetobacter, Flavobacterium, and Chromobacterium. This report emphasizes the importance of bacterial colonization by heterotrophic bacteria in water reservoirs from domestic reverse-osmosis units.Key words: drinking water, bacteria, reverse-osmosis filter, regrowth.

Effects of chlorine level on the growth of biofilm in drinking water pipes

2003 ◽  
Vol 3 (1-2) ◽  
pp. 171-177 ◽  
Author(s):  
C. Chu ◽  
C. Lu ◽  
C.M. Lee ◽  
C. Tasi
Keyword(s):  
Biofilm Formation ◽  
Bacterial Species ◽  
Free Water ◽  
Gram Negative Bacteria ◽  
Water Pipe ◽  
Water Pipes ◽  
Plate Counts ◽  
The Difference ◽  
Heterotrophic Plate Counts ◽  
Chlorine Water

Three analogous laboratory-scale water pipe systems were constructed to study the effects of three chlorine levels of finished water on the growth of biofilm. The experimental results indicated that the heterotrophic plate counts (HPCs) of biofilm for chlorine-free water were approximately 2 and 3 orders of magnitude higher than those for low-chlorine water (0.3-0.5 mg/l Cl2) and high-chlorine water (1.2-1.5 mg/l Cl2), respectively. The difference in HPCs between low-chlorine water and high-chlorine water was below 1 order. Average biofilm formation rates are 325 ATP pg/cm2 per day for chlorine-free water, 159 ATP pg/cm2 per day for low-chlorine water and 118 ATP pg/cm2 per day for high-chlorine water. Scanning electron microscope (SEM) observation showed that bacterial species separated from the biofilm were more complex than from the finished water. The Gram-negative bacteria were dominant.

scholarly journals Filtration Performances of Different Polysaccharides in Microfiltration Process

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 897
Author(s):  
Shujuan Meng ◽  
Hongju Liu ◽  
Qian Zhao ◽  
Nan Shen ◽  
Minmin Zhang
Keyword(s):  
Membrane Fouling ◽  
Xanthan Gum ◽  
Membrane Filtration ◽  
Extracellular Polymeric Substances ◽  
Molecular Structures ◽  
Feed Water ◽  
Permeate Flux ◽  
Small Molecular Weight ◽  
Membrane Pores ◽  
Flux Decline

Membrane technology has been widely applied for water treatment, while membrane fouling still remains a big challenge. The polysaccharides in extracellular polymeric substances (EPS) have been known as a significant type of foulant due to their high fouling propensity. However, polysaccharides have many varieties which definitely behave differently in membrane filtration. Therefore, in this study, different polysaccharides alginate sodium and xanthan gum were chosen to study their effects on membrane fouling in a wide concentration range. The results demonstrated that the filtration behaviors of alginate sodium and xanthan gum were completely different, which was due to their different molecular structures. Alginate had a small molecular weight and it was easy for alginate to penetrate membrane pores resulting in pore blocking. A series of concentrations of alginate including 5 mg/L, 10 mg/L, 20 mg/L, 30 mg/L, 40 mg/L, and 50 mg/L were examined and it was found that the permeate flux decline highly depended on the level of alginate in the feed water. While for the filtration of xanthan gum, the same concentration of xanthan gum led to more serious fouling than that observed in alginate, which might be due to its large molecule. In addition, calcium chloride was added in the solutions of both alginate and xanthan gum to examine the influence of a divalent cation on polysaccharide fouling. A “unimodal” peak can be observed in the fouling propensity caused by Ca2+ and alginate with increasing the concentration of alginate. Such a phenomenon was not found in the fouling of xanthan gum and Ca2+ led to more serious fouling for all concentrations of xanthan gum. In light of this, this study gave new insights into the fouling propensities of different polysaccharides.

Culturable bacterial diversity from a feed water of a reverse osmosis system, evaluation of biofilm formation and biocontrol using phages

2014 ◽  
Vol 30 (10) ◽  
pp. 2689-2700 ◽  
Author(s):  
D. R. B. Belgini ◽  
R. S. Dias ◽  
V. M. Siqueira ◽  
L. A. B. Valadares ◽  
J. M. Albanese ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Reverse Osmosis ◽  
Biofilm Formation ◽  
System Evaluation ◽  
Feed Water

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

2019 ◽  
Author(s):  
Yoshihide Furuichi ◽  
Shogo Yoshimoto ◽  
Tomohiro Inaba ◽  
Nobuhiko Nomura ◽  
Katsutoshi Hori
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Waste Treatment ◽  
Large Cell ◽  
Dlvo Theory ◽  
Bacterial Cells ◽  
Chemical Production ◽  
Discontinuous Surface ◽  
Cell Cell

<p></p><p>Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. <i>Acinetobacter </i>sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.</p><p></p>

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

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