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2 edition of Effects of hydrodynamic conditions and biocides on biofilm control found in the catalog.

Effects of hydrodynamic conditions and biocides on biofilm control

Marielle Dominique Pujo

Effects of hydrodynamic conditions and biocides on biofilm control

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  • 31 Currently reading

Published by University of Birmingham in Birmingham .
Written in English


Edition Notes

Thesis (Ph.D) - University of Birmingham, School of Chemical Engineering, 1993.

Statementby Marielle Dominique Pujo.
ID Numbers
Open LibraryOL20916023M

(B) Effect of biocides on an established (h) P. aeruginosa biofilm in the presence and absence of a low-strength electric field with a low current density. Glutaraldehyde (5 ppm) (open and solid squares) or quaternary ammonium compound (10 ppm) (open and solid diamonds) was supplied to both electrified and control devices for 24 h (mean, n = 2). Biofilm cultures of S. aureus were grown under continuous flow of TSB nutrient to determine the impact of hydrodynamic conditions on the growth of bacteria. The cultures were grown at 37°C and exposed to various fluid flow rates under the control of a BioFlux z flow system (Fluxion Biosciences Inc., South San Francisco, CA).


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Effects of hydrodynamic conditions and biocides on biofilm control by Marielle Dominique Pujo Download PDF EPUB FB2

Hydrodynamic conditions control the composition of the growing biofilm in terms of cells and exocellular polymeric substances (EPS). The cell fraction within the biofilm (R cell) was found to be inversely proportional to the gas velocity.

The specific activity expressed in methane production rate or COD removal rate is higher in biofilms formed Cited by: Hydrodynamic conditions control two interlinked parameters; mass transfer and drag, and will, therefore, significantly influence many of the processes involved in biofilm development.

The goal of this research was to determine the effect of flow velocity and nutrients on biofilm structure. Biofilms were grown in square glass capillary flow cells under laminar and turbulent flows.

The effects of biofilm age on its thickness and roughness were determined under no flow conditions. The average biofilm thickness increased with age, from 20 ± 4 µm for a 4-week biofilm to 38 ± 5 µm for a week biofilm.

After 14 weeks, the biofilm thickness by: The effects of nutrient loading under similar hydrodynamic conditions have been studied in the laboratory. The maximum biofilm thickness was reduced. Pseudomonas fluorescens due to biofilm formation – comparison of biofilms formed under different hydrodynamic conditions.

Submitted. Chapters in books: Simões M. Pereira M. Vieira M. () How the hydrodynamic conditions under which the biofilm are formed affect the effectiveness of aldehyde-base biocides. In: Biofilm. Biofilm formation is crucial for subsequent biofouling.

Various factors can affect the biofilm formation. Here we report the influence of hydrodynamic shear force on adhesion morphology and biofilm conformation of Bacillus sp. on stainless steel by a flow cell system.

Static, laminar and turbulent conditions were selected for this study. A novel strategy for control of microbial biofilms through generation of biocide at the biofilm-surface interface.

Applied and Environmental Microbiology, 62, – Google Scholar. Biofilm formation in clinical settings is an increasingly important issue particularly due to the emergence of multidrug-resistant strains, as it resulted in increased mortality, which poses a considerable financial burden on healthcare systems.

The bacterial biofilms are quite resistant to the routine antimicrobial-based therapies; therefore, the novel strategies are desired in addition to. Biofilms are quite resistant to biocides, so increasing the amount of biocide in the water stream is usually not enough to disinfect a cooling tower.

Biofilm contains a range of potentially harmful organisms that include pathogens like Legionella, and sulfite reducing bacteria that can cause significant corrosion in your HVAC system.

Online monitoring strategies should be adopted and biocidal dosing fine-tuned to keep biofilms under control. Literature on biofilm control strategies in technical systems is rich; however, the choice of the control method often depends on cost, time constraints and the cleanliness (threshold levels) required for a technical process.

The biocide will be consumed as it reacts with materials in the water and planktonic bacteria which means that there may not be sufficient biocide available once it reaches the biofilm.

It is therefore important to Effects of hydrodynamic conditions and biocides on biofilm control book the right amount of biocide available throughout the system to ensure there is enough to allow it to penetrate the biofilm. Therefore, hydrodynamics are expected to influence the growth and development of biofilms in biofiltration processes and control the contact time available for MP biotransformations to occur; the consequences of these competing Effects of hydrodynamic conditions and biocides on biofilm control book on MP.

In this study, we evaluated the effects of the hydrodynamic conditions on the ecology of biofilms produced by Pseudomonas aeruginosa (PA14).

In microfluidic channels, we found that the development of biofilms was regulated by hydrodynamic conditions, but the developed biofilms also changed flow velocity by narrowing flow width. Cell density increased with time, greatly limited by hydrodynamic forces, and supposed to delay biofilm maturation.

After 1 year, a significant impact of shear stress on the taxonomic structure of the prokaryotic community developed on each surface type was observed.

When it occurs, this condition can cause a devastating decline in health. In addition, at the beginning of treatment many people already suffer from this condition, thereby adding to the burden of chronic Lyme disease.

The herbs in Biocidin are shown to reduce or eliminate yeast and to remove yeast biofilms in laboratory experiments. Use of biocides and surfactants to control Pseudomonas fluorescens biofilms: role of the hydrodynamic conditions: Autor(es): Simões, M. Orientador(es): Vieira, M. Data: Resumo(s): Biofilms constitute a protected growth modality that allows the.

Hydrodynamic conditions play a primary role in biofilm growth. Biofilm growth is favored by high velocities. Biofilm development is more pronounced at m s −1 than at m s −1. High flow velocities cause high turbulence of fluid bulk which enhances substrate transfer and biofilm growth, as suggested by numerous authors working on.

The Effects of Velocity on Biocide Use for Biofilm Removal in Flowing Systems, in Heat Transfer— Baltimore, ed. S, Et Genk.|7| Taylor, R. Efficacy of Industrial. Diffusion in microbial films produced by Pseudomonas fluorescens under turbulent flow conditions was studied using an inert substance (LiCl).

Mass transfer coefficients in the biofilm were measured during formation of the biological deposits and for biofilms. Biofilms in drinking water distribution systems (DWDS) could exacerbate the persistence and associated risks of pathogenic Legionella pneumophila (L.

pneumophila), thus raising human health concerns. However, mechanisms controlling adhesion and subsequent detachment of L. pneumophila associated with biofilms remain unclear.

We determined the connection between L. pneumophila adhesion and. However, current disinfection practices show often inefficacy in the control of main goals of this work were the development of effective strategies, based on the application of chemical agents, in order to control biofilms formed by Pseudomonas fluorescens, and the evaluation of the impact of the hydrodynamic conditions under Reviews: 1.

The effect of the hydrodynamic conditions on oxygen consumption rate was studied in a fixed-bed nitrifying reactor. For that purpose, the k L a, the overall oxygen consumption rate and the maximum biofilm respiration rate were measured under several mixing powers.

It was observed that the maximum biofilm respiration rate was dependent on the hydrodynamic conditions. control (no biocide present), indicating that the biocide was exerting very little effect.

At the higher water velocity of m/s biofilm growth appeared to be under control. Work with a similar biocide (Pujo ), demonstrated that continuously dosing at a concentration of 15 mg/l, effectively prevented biofilm.

However, in order to be more effective in the control of biofouling, it is also very important to identify the growth conditions that are less favorable for microbial activity and biofilm formation.

Biofilms are subjected to fluid shear effects, including detachment caused by flowing water (Lawrenceet al., ; Vieiraet al., ). Detachment. A phenomenological model of biocide action against microbial biofilms was derived.

Processes incorporated in the model include bulk flow in and out of a well‐mixed reactor, transport of dissolved species into the biofilm, substrate consumption by bacterial metabolism, bacterial growth, advection of cell mass within the biofilm, cell detachment from the biofilm, cell death, and biocide.

In marine settings, biofilms reduce the hydrodynamic efficiency of ships and propellers. Fire protection systems represent a particularly complex challenge for biological fouling prevention and control (Mittelman, ). Fluid flow is nearly always stagnant, and the piping conduits are not designed to facilitate routine cleaning operations.

The activities of biocides on established S. aureus and P. aeruginosa biofilms were studied using the DMMB-resazurin and crystal violet-resazurin assays, respectively.

Both protocols can discriminate between activity on viable microorganisms and that on the biofilm matrix. The variable nature of biofilms can be illustrated from scan-ning electron micrographs of biofilms from an industrial water system and a medical device, respectively (Figures 1 and 2).

*Centers for Disease Control and Prevention, Atlanta, Georgia, USA The water system biofilm is highly complex, containing F. The biocides often target the microorganisms that create the initial biofilm, typically bacteria.

Once dead, they are unable to spread and can detach. Other biocides are toxic to larger organisms in biofouling, such as the fungi and algae. The most commonly used biocide, and anti-fouling agent, is the tributyltin moiety (TBT).

Also, normal biocides application modes cannot fulfil the need for biofilm control. In this study, diesel oil was used as the experimental subject representing leaking petroleum products; the effect of diesel addition on biofilm preponderant bacteria diversity and the bactericidal effect of chlorine dioxide and tetradecyl dimethyl benzyl.

Biofilms are the aggregation of microbial cells, which are associated with the surface in almost an irreversible manner, i.e. cannot be removed by gently rising [].They are attached with a biotic or abiotic surface integrated into the matrix that they have produced [].An accustomed biofilm provides favorable conditions for genetic material mobility between the cells and has a defined architecture.

The study of biofilms has skyrocketed in recent years due to increased awareness of the pervasiveness and impact of biofilms. It costs the USA literally billions of dollars every year in energy losses, equipment damage, product contamination and medical infections.

To raise awareness of the role of environmental biofilm in the emergence and spread of antibiotic resistance and its consideration in antimicrobial stewardship.

Antibiotic resistance is a major threat to public health. Overuse of antibiotics, increased international travel, and genetic promiscuity amongst bacteria have contributed to antibiotic resistance, and global containment efforts have. @article{osti_, title = {Performance of hydrogen peroxide as a cooling water biocide and its compatibility with other cooling water inhibitors}, author = {Coughlin, M F and Steimel, L}, abstractNote = {Hydrogen peroxide has been evaluated in a pilot cooling tower system as an alternative to continuous chlorination and intermittent dosing with non-oxidizing biocides.

dependent on the conditions (presence or absence of an EF-CD)underwhichthe biofilm wasestablished. The final set of experiments was performed to demon-strate the relative contributions of the EF-CD and biocide (glutaraldehyde orquatemaryammoniumcompound)to the overall effect.

Established (h) biofilms were monitored. Microorganisms attach to surfaces and develop biofilms. Biofilm-associated cells can be differentiated from their suspended counterparts by generation of an extracellular polymeric substance (EPS) matrix, reduced growth rates, and the up- and down- regulation of specific genes.

Attachment is a complex process regulated by diverse characteristics of the growth medium, substratum, and cell surface. Biofilms In Medicine Industry And Environmental Biotechnology. Download and Read online Biofilms In Medicine Industry And Environmental Biotechnology ebooks in PDF, epub, Tuebl Mobi, Kindle Book.

Get Free Biofilms In Medicine Industry And Environmental Biotechnology Textbook and unlimited access to our library by created an account. Fast Download speed and ads Free. @article{osti_, title = {A review of the effects of dissolved ozone on the corrosion behavior of metals and alloys}, author = {Brown, B E and Duquette, D J}, abstractNote = {Ozone is currently being considered as a possible replacement for chlorine based compounds as a biocide.

Yet, a review of current literature related to the corrosion behavior of metals and alloys exposed to ozonated. phase the biofilm reaches equilibrium and the growth rate equals the detachment rate.

Physical and environmental factors as well as hydrodynamic forces play critical roles during this phase. Factors known to have an impact on the thickness of the biofilm include temperature, pH, nutrient availability, and flow velocity (O’Toole et al.Tsai. The effective use of both oxidizing and non-oxidizing biocides for control of MIC in cooling water systems was evaluated.

A patented localized corrosion monitor was used to monitor changes in localized corrosion rates within laboratory scale and pilot cooling tower systems under various biocide.

This study aimed to investigate the effect of sub-minimum inhibitory concentrations (sub-MICs) of three food-grade biocides (benzalkonium chloride -BZK- trisodium phosphate -TSP- and sodium hypochlorite -SHY-) on Salmonella biofilms. The structural parameters and bacterial viability of the biofilms formed by a S.

Typhimurium isolate from poultry was investigated by means of confocal .In addition, there exists an optimum hydrodynamic flow across the biofilm that favors growth and perfusion rather than erosion of the outermost layers.

Other factors that control biofilm maturation include internal pH, oxygen perfusion, carbon source, and osmolarity (8, 73). At some point, the biofilm reaches a critical mass, and a dynamic.

The hydrodynamic condition may cause different effects on biofilm accumulation and detachment. Increase in flow velocity initially increases the nutrient transport rates until it reaches maximum and then decreases with the further increase in flow velocity.

Besides, the flow velocity increases the biofilm density and detachment.