These biofilms grow on support media by feeding off the organic matter and nutrients in the wastewater that flows over them.
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How does biofilm clean up wastewater?
Oct 26, 2015 · Wastewater treatment with biofilm systems has several advantages, including operational flexibility, low space requirements, reduced hydraulic retention time, resilience to changes in the environment, increased biomass residence time, high active biomass concentration, enhanced ability to degrade recalcitrant compounds as well as a slower …
Why is biofilm formation important?
Sep 05, 2017 · What are the biofilm functions in wastewater treatment Biofilms act to increase microbial population density in flow through systems. In attached growth, surface biofilms prevent hydraulic washout and promote more efficient pollution removal than seen in lagoons or ponds. Suspended growth systems with secondary clarification use gravity settling to keep …
Are biofilm-mediated wastewater treatment technologies a viable alternative to conventional methods?
Jul 13, 2016 · Biological wastewater treatment systems play an important role in improving water quality and human health. This chapter thus briefly discusses different biological methods, specially biofilm technologies, the development of biofilms on different filter media, factors affecting their development as well as their structure and function.
How do we maintain pH during biofilm formation?
Biological wastewater treatment systems play an important role in improving water quality and human health. This chapter thus briefly discusses different biological methods, specially biofilm...
What is a biofilm?
A biofilm is a natural colony of microorganisms (such as bacteria, fungi, or protists) that loosely attach to a surface and then bond to it. They grow, layer upon layer, in a slimy, protective matrix of biopolymers called extracellular polymeric substances (EPS).
What is membrane aerated biofilm reactor?
A membrane aerated biofilm reactor (MABR) is a revolutionary wastewater treatment technology that improves nutrient removal and cuts the energy requirements of the aeration cycle by as much as 90% compared to legacy activated sludge systems.
How do microorganisms communicate with each other?
The microorganisms signal one another chemically within the complex , three-dimensional structures of the mature biofilm , which becomes internally latticed with water channels that the microorganisms use to exchange nutrients and waste products. This natural process can clean wastewater.
What is a MABR module?
MABR technology uses a biofilm, with its sophisticated structures and defenses, to treat wastewater efficiently and organically. Fluence’s MABR modules contain a spirally wound, semipermeable membrane submerged in mixed liquor. Spacers allow the two-layer membrane to form an envelope of air that feeds aerobic organisms.
Why are biofilms important?
Biofilms are important in water and wastewater treatment systems. Biofilms are aggregates of microorganisms suspended in a matrix of extracellular polymeric substances attached to a surface. Their resistance to toxic shocks and retention of slow-growing microorganisms make biofilms advantageous wastewater treatment strategies, achieving efficient removal of a variety of contaminants. Conversely, biofilm mass transfer resistance and predation protection allow them to persist in water distribution systems and other treatment infrastructure where they corrode pipes, reduce pressure head, and allow pathogen persistence. This chapter outlines fundamental biofilm processes, highlights the benefits of biofilm treatment processes, and describes strategies for biofilm control.
What is IFAS in wastewater treatment?
In this study, a laboratory-scale continuous-flow, mixed-growth biological treatment process, based on the integrated fixed-film activated sludge (IFAS) process, was configured using granular activated carbon as the attached-growth media. With potential to degrade target organics, the application of this process for treating the petrochemical industry wastewater may provide a flexible, more efficient, and inexpensive replacement for the activated sludge and other biological treatment processes. The laboratory-scale IFAS configuration was experimented to evaluate the process ability to enhance the biodegradation process utilizing both suspended growth and attached growth, to evaluate its ability to remove nitrogen and phosphorous, and to identify conditions of predominance of attached versus suspended growth. Ratios of attached to suspended growth reached 3 at steady-state conditions; the laboratory-scale flow-through column reached a steady-state operation in 1–2 h, promising smaller tank volumes on a large-scale application. The organics’ removal rates were found to be sensitive to higher initial concentrations and higher hydraulic loading within the range tested in this work. However, nitrogen and phosphorous removal rates were low, and it was mainly attributed to the low total phosphorous-to-chemical oxygen demand ratio representing the bottleneck for upscaling this process.
What is biofilm in biology?
Formation of biofilm is a survival strategy for bacteria and fungi to adapt to their living environment, especially in the hostile environment. Under the protection of biofilm, microbial cells in biofilm become tolerant and resistant to antibiotics and the immune responses, which increases the difficulties for the clinical treatment ...
Where is biofilm found?
Bacterial biofilm formation is widely found in natural environments with water, and also in human diseases, especially in the patients with indwelling devices for the purpose of medical treatments.2,7With the progress of medical sciences, more and more medical devices and/or artificial organs are applied in the treatment of human diseases.
What are the amyloids in bacteria?
Beside of the focus on QS and c-di-GMP, bacterial amyloids have become another popular topic. Amyloids has been identified in both bacteria and fungi, since many types of bacterial species relay on amyloids to stick to each other or further to host surfaces resulting in the creation of biofilms.
Can antibiotics eradicate biofilm?
According to the biofilm characters of antibiotic resistance, it is currently difficult to eradicate biofilm infections by conventional antibiotic treatments. Therefore, the removal of a foreign body becomes an important prerequisite for the eradication of such biofilm infections.
Is an abscess a biofilm?
Abscesses are not biofilm, but they have some kinds of connections with biofilm.45When an abscess is formed, it becomes difficult for antibiotic to penetrate through the wall of abscess into the focus. Therefore empty of abscess is necessary. Early and aggressive antibiotic treatments against biofilm infections.
Can infection cause acidosis?
It is well known that infection could lead to inflammation, which results in faster metabolism and significant consumption of oxygen locally or systemically. If oxygen supply could not meet the demand, glycolysis will be activated leading to acidosis, and the effects of antibiotics could be affected by pH values.
Is biofilm a chronic infection?
According to the features of biofilm development, mature biofilms are significantly resistant to antibiotic chemotherapies and they will intermittently disperse planktonic bacterial cells to the environments. Hence, a typical biofilm infection is usually a chronic infection ...
What is biofilm in biology?
Biofilms are structured microbial communities of single or multiple populations in which microbial cells adhere to a surface and get embedded in extracellular polymeric substances (EPS). This review attempts to explain biofilm architecture, development phases, and forces that drive bacteria to promote biofilm mode of growth. Bacterial chemical communication, also known as Quorum sensing (QS), which involves the production, detection, and response to small molecules called autoinducers, is highlighted. The review also provides a brief outline of interspecies and intraspecies cell–cell communication. Additionally, we have performed docking studies using Discovery Studio 4.0, which has enabled our understanding of the prominent interactions between autoinducers and their receptors in different bacterial species while also scoring their interaction energies. Receptors, such as LuxN (Phosphoreceiver domain and RecA domain), LuxP, and LuxR, interacted with their ligands (AI-1, AI-2, and AHL) with a CDocker interaction energy of − 31.6083 kcal/mole; − 34.5821 kcal/mole, − 48.2226 kcal/mole and − 41.5885 kcal/mole, respectively. Since biofilms are ideal for the remediation of contaminants due to their high microbial biomass and their potential to immobilize pollutants, this article also provides an overview of biofilm-mediated bioremediation.
How does biofouling work?
Biofouling in environmental systems employs bacterial quorum sensing signals (autoinducers) and extracellular polymeric substances to onset the event. The present review has highlighted on the fundamental mechanisms behind biofilm formation over broad spectrum environmental niches especially membrane biofouling in water systems and consequent chances of pathogenic contamination leading to global economic loss. It has broadly discussed on bioelectrical signal (via, potassium gradient) and molecular signal (via, AHLs) mediated quorum sensing which help to propagate biofilm formation. The review has illustrated the potential of genomic intervention towards biofouled membrane microbial community and has uncovered possible features of biofilm microenvironment like quorum quenching bacteria, bioelectrical waves capture, siderophores arrest and surface modifications. Based on information, the concept of interception of quorum signals (AHLs) and bioelectrical signals (K+) by employing electro-modified (negative charges) membrane surface have been hypothesized in the present review to favour anti-biofouling.
What are fixed film processes?
Fixed film processes and activated sludge processes are two main families of wastewater treatment systems which all refer to the heterogeneous microbial communities. Meanwhile, biofilms in drinking water distribution systems (DWDS) and biofouling in membrane systems are significant problems in the water and wastewater treatment which reduce the microbial quality of drinking water and limit the development of membrane system respectively. Since biofilms and quorum sensing (QS) as two microbial social behaviors have been inextricably linked, a number of studies have focused on the role of QS signaling and QS inhibition in the processes of water and wastewater treatment, which will help us engineer these biological treatment processes successfully and develop promising approaches for control of microbial adhesion, colonization and biofilm formation. This review gives a summary of recent known QS mechanisms and their role in biofilm formation for different species. Particular attentions are dedicated to the signaling molecules involved in some microbial granulation processes and the potential applications by some of their natural and synthetic analogues in the treatment of membrane biofouling.
What is aerobic granulation?
Aerobic Granules are special type of self-immobilization of microorganisms, without any surface medium for growth of microbial film. They have compact cores and have high diffusional confrontations to external particles and, hence have high acceptance of the toxic compounds to their integral cells. Most aerobic granules are large and have a compact core, and so are recommended for use in the biological treatment of high-strength industrial wastewaters. This technology requires small foot print, 25% of the area of conventional activated sludge setup and this process can reduce up to 50% on energy-costs. This paper reviews on start-ups, advances in aerobic granulation technology from laboratory studies to pilot scale and to its full-scale application for treatment of different types of domestic and industrial wastewater. Gaps in knowledge and new ideas for future work of aerobic granulation technology are also being discussed.
What is quorum sensing in wastewater?
Quorum sensing (QS) and quorum quenching (QQ) are increasingly reported in biological wastewater treatment processes because of their inherent roles in biofilm development, bacterial aggregation, granulation, colonization, and biotransformation of pollutants. As such, the fundamentals and ubiquitous nature of QS bacteria are critical for fully understanding the process of the wastewater treatment system. In this article, the details of QS-based strategies related to community behaviors and phenotypes in wastewater treatment systems were reviewed. The molecular aspects and coexistence of QS and QQ bacteria were also mentioned, which provide evidence that future wastewater treatment will indispensably rely on QS-based strategies. In addition, recent attempts focusing on the use of QQ for biofilm or biofouling control were also summarized. Nevertheless, there are still several challenges and knowledge gaps that warrant future targeted research on the ecological niche, abundance, and community of QS- and QQ-bacteria in environmental settings or engineered systems.
What is indole used for?
Indole is long regarded as a typical N-heterocyclic aromatic pollutant in industrial and agricultural wastewater, and recently it has been identified as a versatile signaling molecule with wide environmental distributions. An exponentially growing number of researches have been reported on indole due to its significant roles in bacterial physiology, pathogenesis, animal behavior and human diseases. From the viewpoint of both environmental bioremediation and biological studies, the researches on metabolism and fates of indole are important to realize environmental treatment and illuminate its biological function. Indole can be produced from tryptophan by tryptophanase in many bacterial species. Meanwhile, various bacterial strains have obtained the ability to transform and degrade indole. The characteristics and pathways for indole degradation have been investigated for a century, and the functional genes for indole aerobic degradation have also been uncovered recently. Interestingly, many oxygenases have proven to be able to oxidize indole to indigo, and this historic and motivating case for biological applications has attracted intensive attention for decades. Herein, the bacteria, enzymes and pathways for indole production, biodegradation and biotransformation are systematically summarized, and the future researches on indole-microbe interactions are also prospected.
What is QS in wastewater?
Quorum sensing (QS) is a communication mode between microorganisms to regulate bacteria ecological relations and physiological behaviors, thus achieve the physiological function that single bacteria can not complete. This phenomenon play important roles in the formation of biofilm and granular sludge, and may be related to enhancement of some functional bacteria activity in wastewater treatment systems. There is a need to better understand bacterial QS in engineered reactors, and to assess how designs and operations might improve the removal efficiency. This article reviewed the recent advances of QS in several environmental systems and mainly analyzed the regulation mechanism of QS-based strategies for biofilm, granular sludge, functional bacteria, and biofouling control. The co-existences of multiple signal molecules in wastewater treatment (WWT) processes were also summarized, which provide basis for the future research on QS mechanism of multiple signal molecules interaction in WWT. This review would present some prospects and suggestions which are of practical significance for further application.
What is the development of biofilms?
The development of a biofilm includes attachment of cells to a surface, multiplication, maturation, and production of a polymeric matrix, and finally microbial detachment and colonization of new surfaces. The heterogeneity of biofilms results in increased tolerance to antimicrobials due to the inherent physical and chemical barriers.
Why is biofilm important?
Biofilm formation is an important survival strategy that bacteria utilize in natural and human-made niches. The detection of adherence of pathogenic bacteria on medical surfaces is necessary to identify and prevent systemic infections related to biofilm-forming bacteria.
What is biofilm?
Biofilm formation is an important biological concept in environmental microbiology, wherein the microbial cells adapt to multicellular lifestyle by formation of biofilm during which the bacterial cells are self-immobilized in extracellular polymeric matrix. This chapter provides an insight into the concept of biofilm formation by microorganisms ...
How does biofilm form?
Biofilm formation begins with the adhesion of bacteria onto the electrode surface, followed by the coadhesion and proliferation of microbial cells by the formation of multilayer cell clusters.
What are the parameters that determine biofilm formation?
Biofilm formation also depend upon different physicochemical parameters, which include pH, temperature, substrate, and ion concentration, etc. This is due to both bacterial and material surfaces being influenced by their surrounding environmental conditions [20].
What is biofilm formation?
Biofilm formation represents a natural process in all planktonic microbes’ native environments. Many researches made an effort to explain factors which influence the transition of microbes from planktonic to biofilm lifestyles and their adhesion to the surface (Davies and Geesey, 1995; Li and Burne, 2001; Svensater and Bergenholtz, 2004 ). If environmental conditions become adverse, oral bacteria may exhibit the capacity to alter their gene expression and express new phenotypes in order to enable different behaviors, which will enhance their survival ( Davies and Geesey, 1995 ).
What is biofouling in biology?
Biofouling is the colonization of submerged surfaces by microorganisms such as bacteria and has destructive effects on artificial devices used in different fields ( Varin et al., 2013; Yoon et al., 2013 ).