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admin | Get Rid Of Bacterial Infection | 20.07.2015
Simply put, aerobic wastewater treatment refers to the removal of organic pollutants in wastewater by bacteria that require oxygen to work. Watch these short videos and see for yourself just how easy the software is to use and fast to construct. The software simplifies the design while using the most comphrensive formula’s to provide you with tank sizes, clarifier sizes, carbon addition and effluent quality. Anaerobic digestion is a bacterial process that is used to break down sludge in the absence of oxygen. Stabilization of the organic material occurs during methane fermentation (Davis and Masten, 2004). Figure 1A biofilm is composed of attached microbial cells encased within a matrix of extracellular polymeric secretions (EPS), which surround and protect cells.
Overall, the biofilm state provides a more stable microenvironment for bacteria and other microbial cells.
With their steep gradients of pH, temperature, pressure, and metals, deep-sea hydrothermal vents are an excellent example of the extreme natural conditions to whic microorganisms can physiologically adapt..
Figure 2Microbial biofilms associated with active hydrothermal edifices at the Lost City Hydrothermal Field, Mid-Atlantic Ridge. Biofilms and the plethora of organisms that live at deep-sea vent sites are based on the process of chemoautotrophy. Other types of high-temperature microbial biofilm communities occur near the earth's surface at terrestrial hot springs such as those of Yellowstone National Park (Wyoming, USA). Biofilms are also common in engineered systems and may constitute both a problem for and a solution to engineering endeavors. Figure 3Scanning electron microscopy (SEM) micrographs of the biofilm formed on cast iron coupons at (a and b) 37 and 70 days, respectively, without disinfectant; (c and d) 37 and 70 days, respectively with the disinfectant chlorine.
On the other hand, recent studies have shown that biofilms are also capable of suppressing corrosion (Zuo 2007; Stadler et al. Biofilms are widely used in environmental engineering systems as the powerhouse of treatment processes. Biofiltration in drinking water treatment has been gaining increasing interest in recent years as a potential way to reduce the formation of disinfection byproducts (DBPs) (Hozalski et al. In wastewater treatment, nutrient removal is an essential outcome to protect the natural environment from eutrophication and unwanted contamination. In all cases, the advantage of utilizing biofilms in water and wastewater treatments is attributed to the ‘stickiness' of the biofilm matrix. As a product of physiological adjustments made by microorganisms in response to environmental stressors, biofilms are ubiquitous in ecosystems, even under extreme conditions. The support of the US National Science Foundation (Grant numbers BME-1032579 and DMR-1206072) is gratefully acknowledged. Without wastewater treatment plans, pollution due to wastewater can not be handled by the environment. Wastewater treatment is a multi-stage process to renovate wastewater before it reenters an environment. Most bacteria live in a biofilm state to enhance their survival and propagation, and to perform essential tasks for many ecosystems. They often show remarkable organization and can communicate, coordinate, and cooperate with each other.
The EPS matrix is typically composed of polysaccharides, proteins, lipids, and extracellular DNA (eDNA). A biofilm forms when one or several bacterial cells suspended in the water attach to a surface.
This microenvironment can rapidly adapt to stressors and coordinate activities in response to changes imposed by the environment, other organisms, or both. It appears that the formation of biofilms is a crucial strategy that microbes use to withstand this harsh environment (Edwards et al.


Bacterial biofilms are closely associated with such hydrothermal structures where abundant mineral precipitation occurs. These thick biofilms, called microbial mats, are fueled by photosynthetic fixation of carbon into organic molecules, in contrast to the chemoautotrophic-based carbon fixation found at the deep-sea vents.
Nutrient removal is achieved primarily by biological means; the most common is through the use of activated sludge, which is a mixture of flocs.
The complex and heterogeneous EPS matrix often captures and immobilizes organic and inorganic contaminants that need to be removed, such as pathogens, heavy metals, and nanoparticles (Searcy et al. Our daily activities such as taking a shower, flushing the toilet, running the washing machine or dishwasher produce wastewater. The goal is to reduce or remove organic matter, solids, nutrients, disease-causing organisms, and other pollutants from wastewater.
Processes include trickling filtration, activated sludge, and rotating biological contractors. Anaerobic digesters - also known as biodigesters - are made out of concrete, steel, brick, or plastic.
The biofilm begins to dispel the notion that bacteria are simply many single cells out for themselves in favor of the idea that they can act as groups of cooperating cells to enhance their individual fitness and increase the efficiency of the biofilm. The species and metabolic diversity that typically develop within a biofilm afford the community greater adaptability and enhanced ecological persistence. Microbial biomass abundantly associates with vent chimneys of either sulfide or carbonate, and varies with the degree of hydrothermal activity (Schrenk et al. Indeed, researchers believe that studying hydrothermal vents may aid in answering one of biology's most fundamental questions: What is the origin of life? Mitigation of corrosion is estimated to cost 3% of the world's gross domestic product (~$1.9 trillion per year) (Koch et al. Flocs are equivalent to biofilms formed in suspension, rather than attached to surfaces, where cells of various species are glued together by EPS, forming a suspended biofilm having a complex microbial community. The BOD5 measures the amount of oxygen required by microorganism to degrade the organic material in the wastewater in five days. Each receiving body of water has limits to the amount of pollutants it can receive without degradation. Bacteria that thrive in oxygen-rich environments work to break down and digest the wastewater inside the aerobic treatment plant or system. We are able to service your needs for aerobic wastewater treatment plants and anaerobic wastewater treatment plants, anywhere in the continental United States and parts of Canada. They are shaped like silos, troughs, basins or ponds, and may be placed underground or on the surface (Darling, 2008). This is not altruism per se, but rather by exploiting the biofilm, individual fitness is enhanced by the interactions. The bacteria of deep-sea hydrothermal vents can experience toxic metals coupled with temperatures changing from >100 oC to near freezing (0 oC) within minutes. As the biofilm develops, different sets of genes are turned on (up-regulated) or off (down-regulated). These unique characteristics allow biofilms to be present in virtually every corner of natural or engineered environments and, often, to be an integral component of such environments. These contradictory reports suggest that relationships between corrosion and biofilms require better understanding of the diverse biofilm communities and of the factors that induce or inhibit corrosion. In both cases, bacteria are utilized for their ability to rapidly break down and transform complex organic compounds into simple forms that have fewer negative impacts on the receiving environment. DBPs are formed through chemical reactions between disinfectants, such as chlorine, and natural organic matter (NOM) (Hua and Reckhow 2007). This community of cells then breaks down a wide variety of organic compounds as well as nitrogen and phosphorous compounds. The rapid physiological adaptation capabilities of biofilms also adds a major advantage: bacteria recover faster from stress caused by random occurrences of toxic substances in the influent water, thus enabling reliable water and wastewater treatment.


Finally, bacteria experience varying levels of nutrients such as nitrate, phosphate, and sulfates, and the presence or absence of oxygen and water.
Therefore bacteria in biofilms express genes differently when compared with similar bacteria as planktonic cells. Some biofilms are found in extremely toxic environments and others act as the workhorse of man-made systems. Despite the presence of residual disinfectant in treated drinking water, biofilms often develop on the inner surfaces of distribution pipes (Figure 3), possibly because the nutrient-poor nature of treated drinking water flowing through pipes facilitates biofilm formation as a physiological adaptation response.
While some biofilm bacteria are troublemakers, others offer free and hardworking labor for humans. Specifically, biofilm bacteria are much more efficient than planktonic cells in many treatment systems; the immobilized cells in biofilms will not be washed away, thus allowing for continuous treatment of large volumes of water. While DBP formation can be reduced by changing the disinfectant used, another method is to decrease quantities of NOM in water using biofiltration, which occurs prior to disinfectant addition.
Similarly, surface-attached biofilms are used in some wastewater treatment plants in the form of trickling filters. Wherever bacteria live, they are exposed to many different stresses that compromise their ability to grow and even survive. Finally, bacteria release signal molecules for a process of chemical communication called quorum sensing. In such cases, biofilms are traditionally known to be responsible for causing or accelerating corrosion, a process known as biocorrosion or microbiologically-induced corrosion (MIC) (Beech 2004; Little et al.
Granular media filters can be converted to biofilters simply by allowing biofilm growth on media surfaces. These trickling filters are similar to biofilters in drinking water with the same objective of nutrient removal as the activated sludge process. To overcome these stresses, they have developed adaptive strategies that help stabilize their local environment and ecological success.
The EPS matrix affords protection to cells and enhances gathering of nutrients through sorption of organics (Decho 1990). These biofilms then break down NOM during filtration, resulting in much lower organic carbon levels that react with disinfectants to form DBPs.
Another advantage of using biofiltration is that biofilm activity can also minimize taste and odor issues in drinking water by removing related organic compounds (Huck et al. This allows cells to fix their positions relative to one another, much in the same way that people live in different rooms of a high-rise apartment building. The EPS also forms a confining scaffold to slow diffusive loss and localize extracellular enzymes and extracellular DNA, which is actively secreted by cells as plasmids, or released by lysed cells. MIC is typically caused by the presence of biofilm-derived enzymes and acids that facilitate metal dissolution. The proximity of cells to one another facilitates exchange of plasmids and free DNA, a process that can quickly arm bacteria with the necessary genetic machinery to persist through stresses.
Finally, biofilm-forming bacteria use chemical communication, called quorum sensing, to coordinate their metabolism (Camilli and Bassler 2006). Bacteria release chemical signals that are sensed by other nearby cells within the biofilm. Thus, groups of bacteria in spatial proximity can coordinate their activities, a process that increases the efficiency and resilience of the community.



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